Organotungsten chemistry

The simplest tungsten carbonyl complex is tungsten hexacarbonyl, most commonly prepared via reductive carbonylation (for instance, reaction of WCl₆ and zinc powder under a CO atmosphere{{Cite journal |last1=Bruno |first1=Sofia M. |last2=Valente |first2=Anabela A. |last3=Gonçalves |first3=Isabel S. |last4=Pillinger |first4=Martyn |date=2023-03-01 |title=Group 6 carbonyl complexes of N,O,P-ligands as precursors of high-valent metal-oxo catalysts for olefin epoxidation |url=https://linkinghub.elsevier.com/retrieve/pii/S0010854522005781 |journal=Coordination Chemistry Reviews |volume=478 |pages=214983 |doi=10.1016/j.ccr.2022.214983 |issn=0010-8545|doi-access=free }}) of tungsten halides and similar compounds. Tungsten hexacarbonyl itself is able to catalyze alkene metathesis.{{Cite book |last1=Greenwood |first1=N. N. |title=Chemistry of the elements |last2=Earnshaw |first2=A. |date=1997 |publisher=Butterworth-Heinemann |isbn=978-0-7506-3365-9 |edition=2nd |location=Oxford ; Boston |pages=1037–1039}} Being volatile and easily decomposed, it is also widely used in the electron beam-induced deposition technique to deposit tungsten atoms.{{Cite journal |last1=Randolph |first1=S. J. |last2=Fowlkes |first2=J. D. |last3=Rack |first3=P. D. |date=2006-09-01 |title=Focused, Nanoscale Electron-Beam-Induced Deposition and Etching |url=https://www.tandfonline.com/doi/full/10.1080/10408430600930438 |journal=Critical Reviews in Solid State and Materials Sciences |volume=31 |issue=3 |pages=55–89 |doi=10.1080/10408430600930438 |bibcode=2006CRSSM..31...55R |issn=1040-8436}} Reduction of the hexacorbonyl (in liquid ammonia with borohydride and sodium metal, respectively) yields the anionic carbonyl complexes [W₂(CO)₁₀]^2- & [W(CO)₄]^4-.{{Cite book |last1=Greenwood |first1=N. N. |title=Chemistry of the elements |last2=Earnshaw |first2=A. |date=1997 |publisher=Butterworth-Heinemann |isbn=978-0-7506-3365-9 |edition=2nd |location=Oxford ; Boston |pages=1037–1039}} Also known are the complexes [W(CO)₅]^2- & [W₃(CO)₁₄]^2-.{{Cite journal |last1=Zavarine |first1=Igor S. |last2=Kubiak |first2=Clifford P. |date=1998-04-01 |title=Organometallic "super reducing agents". Electron transfer chemistry of photogenerated 19e− W(CO)5(L)− radicals |url=https://linkinghub.elsevier.com/retrieve/pii/S0010854598900650 |journal=Coordination Chemistry Reviews |series=Twelfth International Symposium on Photochemistry and Photophysics of Coordination Compounds |volume=171 |pages=419–438 |doi=10.1016/S0010-8545(98)90065-0 |issn=0010-8545}}{{Cite journal |last=Ellis |first=John E. |date=2003-08-01 |title=Metal Carbonyl Anions: from [Fe(CO)4]2- to [Hf(CO)6]2- and Beyond |url=https://pubs.acs.org/doi/10.1021/om030105l |journal=Organometallics |volume=22 |issue=17 |pages=3322–3338 |doi=10.1021/om030105l |issn=0276-7333}}{{Cite journal |last1=Beletskaya |first1=Irina P. |last2=Voskoboynikov |first2=Alexander Z. |last3=Chuklanova |first3=Elena B. |last4=Gusev |first4=Alexey I. |last5=Kisin |first5=Alexander V. |date=1993-07-27 |title=Metalcarbonylates of lanthanides. Unexpected formation of the trinuclear cluster [Na(DME)3]2[W3(CO)14] |url=https://linkinghub.elsevier.com/retrieve/pii/0022328X9383215H |journal=Journal of Organometallic Chemistry |volume=454 |issue=1 |pages=1–3 |doi=10.1016/0022-328X(93)83215-H |issn=0022-328X}}

Substitution of the carbonyl ligand can be facilitated thermally or photochemically, for instance, the reaction with cyclopentadienide to yield [CpW(CO)₃]^-, which can be further derivatized.{{Citation |last1=Chin |first1=Teen T. |title=Dicarbonyl(η5-Cyclopentadienyl)Nitrosyl Complexes of Chromium, Molybdenum, and Tungsten |date=1990 |work=Inorganic Syntheses |pages=196–198 |url=https://onlinelibrary.wiley.com/doi/10.1002/9780470132593.ch50 |access-date=2025-02-11 |publisher=John Wiley & Sons, Ltd |language=en |doi=10.1002/9780470132593.ch50 |isbn=978-0-470-13259-3 |last2=Hoyano |first2=James K. |last3=Legzdins |first3=Peter |last4=Malito |first4=John T. |last5=Arnold |first5=Thomas |last6=Swanson |first6=Basil I.}}{{Cite book |last=Herrmann |first=Wolfgang A. |title=Synthetic methods of organometallic and inorganic chemistry: Herrmann/Brauer |date=1997 |publisher=Georg Thieme Verlag Thieme Medical Pub |isbn=978-3-13-103091-7 |location=Stuttgart |pages=79}} A roundabout substitution method of first using nitriles to displace the carbonyls and then displacing the nitriles is also viable. Alkane complexes of W(CO)₅ can be photochemically produced.{{Cite journal |last1=Paur-Afshari |first1=Riki |last2=Lin |first2=J. |last3=Schultz |first3=Richard H. |date=2000-05-01 |title=An Unusual Solvent Isotope Effect in the Reaction of W(CO)5(solv) (solv = Cyclohexane or Cyclohexane-d12) with THF |url=https://pubs.acs.org/doi/10.1021/om990828y |journal=Organometallics |volume=19 |issue=9 |pages=1682–1691 |doi=10.1021/om990828y |issn=0276-7333}} A niche catalysis reaction utilizes the strong Lewis acidity of the W(CO)₅ fragment, converting thiirane to the sulfur analogs of crown ethers.{{Cite journal |last=Adams |first=Richard D. |date=2000-03-01 |title=Catalytic Macrocyclizations of Thietanes and Thiiranes by Metal Carbonyl Complexes |url=https://pubs.acs.org/doi/10.1021/ar980092l |journal=Accounts of Chemical Research |volume=33 |issue=3 |pages=171–178 |doi=10.1021/ar980092l |pmid=10727206 |issn=0001-4842}} The other common reactivity of alkyl/aryl containing tungsten carbonyl complexes involve carbonyl insertion.

Isocyanide complexes W(CO)_6-n(CNR)_n (n = 1~3) are prepared via ligand substitution of tungsten hexacarbonyl, catalyzed by palladium oxide or cobalt dichloride.{{Cite journal |last1=Albers |first1=Michel O. |last2=Singleton |first2=Eric |last3=Coville |first3=Neil J. |date=1986-05-01 |title=The catalyzed substitution of CO by isonitriles on [M(CO)6](M = Cr, Mo, W): A versatile undergraduate inorganic laboratory experiment. |url=https://pubs.acs.org/doi/abs/10.1021/ed063p444 |journal=Journal of Chemical Education |volume=63 |issue=5 |pages=444 |doi=10.1021/ed063p444 |bibcode=1986JChEd..63..444A |issn=0021-9584}}{{Citation |last1=Albers |first1=Michel O. |title=Zero-Valent Isocyanide Complexes of Chromium, Molybdenum, and Tungsten |date=1990 |work=Inorganic Syntheses |pages=140–145 |url=https://onlinelibrary.wiley.com/doi/10.1002/9780470132593.ch37 |access-date=2025-02-11 |publisher=John Wiley & Sons, Ltd |language=en |doi=10.1002/9780470132593.ch37 |isbn=978-0-470-13259-3 |last2=Coville |first2=Neil J. |last3=Uhm |first3=Haewon L. |last4=Butler |first4=Ian S.}} The reactivity regarding migratory insertion is analogous to that of carbonyl complexes.

Of the cyanide complexes, [W(CN)₈]^n- (n = 3, 4) are notable for their photochemical{{Cite journal |last1=Samotus |first1=A. |last2=Szklarzewicz |first2=J. |date=1993-05-01 |title=Photochemistry of transition metal octacyanides and related compounds. Past, present and future |url=https://linkinghub.elsevier.com/retrieve/pii/001085459385008R |journal=Coordination Chemistry Reviews |volume=125 |issue=1 |pages=63–74 |doi=10.1016/0010-8545(93)85008-R |issn=0010-8545}} and magnetic properties. The face capped cubic cluster compound Mn₉[W(CN)₈]₆•24EtOH, for instance, has the largest known ground state spin value of S = 39/2 (as of 2011).{{Cite journal |last1=Zhong |first1=Zhuang Jin |last2=Seino |first2=Hidetake |last3=Mizobe |first3=Yasushi |last4=Hidai |first4=Masanobu |last5=Fujishima |first5=Akira |last6=Ohkoshi |first6=Shin-ichi |last7=Hashimoto |first7=Kazuhito |date=2000-03-01 |title=A High-Spin Cyanide-Bridged Mn9W6 Cluster (S = 39/2) with a Full-Capped Cubane Structure |url=https://pubs.acs.org/doi/10.1021/ja992622u |journal=Journal of the American Chemical Society |volume=122 |issue=12 |pages=2952–2953 |doi=10.1021/ja992622u |bibcode=2000JAChS.122.2952Z |issn=0002-7863}} Such complexes can also be used in constructing coordination polymers, such as {(Me₃Sn)₄[W(CN)₈]}_n.{{Cite journal |last1=Lu |first1=J. |last2=Harrison |first2=W. T. A. |last3=Jacobson |first3=A. J. |date=1995 |title=Synthesis and Structure of the Three-Dimensional Coordination Polymers [(Me3Sn)4M(CN)8] (M = Mo, W) |url=https://onlinelibrary.wiley.com/doi/10.1002/anie.199525571 |journal=Angewandte Chemie International Edition in English |volume=34 |issue=22 |pages=2557–2559 |doi=10.1002/anie.199525571 |issn=1521-3773}}{{Cite journal |last1=Sieklucka |first1=Barbara |last2=Podgajny |first2=Robert |last3=Korzeniak |first3=Tomasz |last4=Przychodzeń |first4=Paweł |last5=Kania |first5=Rafał |date=2002 |title=Supramolecular networks based on octacyanometallates of Mo and W |url=https://comptes-rendus.academie-sciences.fr/chimie/articles/10.1016/S1631-0748(02)01428-5/ |journal=Comptes Rendus. Chimie |language=fr |volume=5 |issue=10 |pages=639–649 |doi=10.1016/S1631-0748(02)01428-5 |issn=1878-1543}} The coordination polymers are held together via cyanide bridges, with carbon coordinating the tungsten atoms while nitrogen coordinating the other central atoms.

Simple alkyl complexes of tungsten, as those of molybdenum and chromium, are rather unstable. The simplest, hexamethyltungsten, has no molybdenum or chromium analogs. It is extremely reactive, detonating in air or even in vacuum.{{cite journal |author1=Green, J. C. |author2=Lloyd, D. R. |author3=Galyer, L. |author4=Mertis, K. |author5=Wilkinson, G. |year=1978 |title=Photoelectron spectra of some transition metal alkyls and oxoalkyls |journal=J. Chem. Soc., Dalton Trans. |issue=10 |page=1403 |doi=10.1039/DT9780001403}}{{cite journal |author1=Mertis, K. |author2=Galyer, L. |author3=Wilkinson, G. |year=1975 |title=Permethyls of tantalum, tungsten and rhenium: a warning |journal=Journal of Organometallic Chemistry |volume=97 |issue=3 |page=C65 |doi=10.1016/S0022-328X(00)89324-9}} It is prepared with methylating reagents and WCl₆, and further methylation into [WMe₇]^- or [WMe8]^2- is possible when using methyllithium. Heteroatoms like oxygen can insert into the W-C bond, performing oxidation.{{Cite journal |last1=Shortland |first1=Anthony J. |last2=Wilkinson |first2=Geoffrey |date=1973-01-01 |title=Preparation and properties of hexamethyltungsten |url=https://pubs.rsc.org/en/content/articlelanding/1973/dt/dt9730000872 |journal=Journal of the Chemical Society, Dalton Transactions |language=en |issue=8 |pages=872–876 |doi=10.1039/DT9730000872 |issn=1364-5447}} WMe₆ adopts the geometry of distorted trigonal prismatic, which may be attributed to a second-order Jahn-Teller distortion{{cite journal |last1=Seppelt |first1=Konrad |year=2003 |title=Nonoctahedral Structures |journal=Accounts of Chemical Research |volume=36 |issue=2 |pages=147–153 |doi=10.1021/ar020052o |pmid=12589700}}{{cite journal |author=Kaupp, M. |year=1998 |title=The Nonoctahedral Structures of d0, d1, and d2 Hexamethyl Complexes |journal=Chemistry: A European Journal |volume=4 |issue=9 |pages=1678–86 |doi=10.1002/(SICI)1521-3765(19980904)4:9<1678::AID-CHEM1678>3.0.CO;2-N}}{{Cite book |title=Inorganic Chemistry |date=2018 |publisher=Pearson Education, Limited |isbn=978-1-292-13414-7 |edition=5. Auflage |location=Harlow |pages=702}} (for further details, see the article on hexamethyltungsten).

File:Les distortos le Hexa.pngStabilization of these compounds are possible via dimerization, as in the compound (Me₃SiCH₂)₃W≡W(CH₂SiMe₃)₃. Note that lack of beta hydrogen atoms are necessary to prevent beta-elimination.{{Cite book |last1=Greenwood |first1=N. N. |title=Chemistry of the elements |last2=Earnshaw |first2=A. |date=1997 |publisher=Butterworth-Heinemann |isbn=978-0-7506-3365-9 |edition=2nd |location=Oxford ; Boston |pages=1037–1039}} Neutral mononuclear complexes of different alkyl numbers are known, such as tetrabenzyltungsten (W(CH₂Ph)₄).{{Cite journal |last1=Thiele |first1=K.-H. |last2=Russek |first2=A. |last3=Opitz |first3=R. |last4=Mohai |first4=B. |last5=Brüser |first5=W. |date=1975 |title=Beiträge zur Chemie der Alkylverbindungen von Übergangsmetallen. XIV. Untersuchungen über Benzylwolframverbindungen-Darstellung und Charakterisierung des Wolframtetrabenzyls |url=https://onlinelibrary.wiley.com/doi/10.1002/zaac.19754120103 |journal=Zeitschrift für anorganische und allgemeine Chemie |language=de |volume=412 |issue=1 |pages=11–19 |doi=10.1002/zaac.19754120103 |issn=1521-3749}}

For electron deficient alkyl tungsten complexes, one example that demonstrates their bonding interactions and reactivity is shown below:

File:Reaction of electron-deficient alkyl tungsten.png; note that neopentane is lost in this reaction]]

As with the alkyl tungsten complexes and most hydrocarbyl organometallics, aryl tungsten complexes can be prepared from tungsten halides and hydrocarbylating agents via transmetallation.

The thermolysis of the complexes Cp*W(NO)(aryl)₂ results in the loss of an arene and the formation of aryne complexes (similar reactions are observed for other hydrocarbyl ligands).{{Cite journal |last1=Pamplin |first1=Craig B. |last2=Legzdins |first2=Peter |date=2003-04-01 |title=Thermal Activation of Hydrocarbon C−H Bonds by Cp*M(NO) Complexes of Molybdenum and Tungsten |url=https://pubs.acs.org/doi/10.1021/ar0202215 |journal=Accounts of Chemical Research |volume=36 |issue=4 |pages=223–233 |doi=10.1021/ar0202215 |pmid=12693920 |issn=0001-4842}} The aryne complexes are unstable and readily activate other C-H bonds (for instance, in solvent molcules).

File:Vinyl tungsten complexes.png

Vinyl ligands have two different modes of coordination with tungsten atoms, as depicted:

Synthesis is facilitated via transmetallation, the deprotonation of tungsten alkene complexes, nucleophilic addition to tungsten alkyne complexes, or alkyne insertion into W-H bonds. The isomerization of the η¹ vinyl complexes into carbynes are possible via a [1,2]-hydrogen migration reaction from the alpha carbon, usually via η² vinyl intermediates. Isomerization of the η² vinyl complexes into allyl complexes are also known.{{Cite journal |last1=Frohnapfel |first1=David S |last2=Templeton |first2=Joseph L |date=2000-09-01 |title=Transition metal η2-vinyl complexes |url=https://linkinghub.elsevier.com/retrieve/pii/S0010854500002691 |journal=Coordination Chemistry Reviews |volume=206-207 |pages=199–235 |doi=10.1016/S0010-8545(00)00269-1 |issn=0010-8545}}

File:Alkynyl tungsten.png

Alkynyl complexes of tungsten can be prepared via transmetallation or via the deprotonation of alkyne or carbene complexes of tungsten. An exotic method of preparation involves the reaction between [CpW(CO)₃]^- and CH₂I₂, forming the bridged complex [CpW(CO)₃](C≡C)[CpW(CO)₃] (along with side products).{{Cite journal |last1=Yang |first1=Yu-Lee |last2=Wang |first2=Luxti Jun-Jieh |last3=Lin |first3=Ying-Chih |last4=Huang |first4=Shou-Ling |last5=Chen |first5=Ming-Chou |last6=Lee |first6=Gene-Hsiang |last7=Wang |first7=Yu |date=1997-04-01 |title=Chemistry of Bridging Ketene from Facile Carbonylation of a Ditungsten Methylene Complex with No Metal−Metal Bond |url=https://pubs.acs.org/doi/abs/10.1021/om9609980 |journal=Organometallics |volume=16 |issue=8 |pages=1573–1580 |doi=10.1021/om9609980 |issn=0276-7333}} The main reactivity involves electrophilic attack on the beta-carbon (which forms vinylidene complexes), as explained in the resonance forms, and it is enhanced with the increasing electron density of the complex. Less common are electrophilic attack on the alpha carbon, which produces alkyne complexes, or electrophilic attack on the tungsten atom (as in the case when reacting with allylic halides) to produce allyl tungsten complexes.{{Cite journal |last1=Ipaktschi |first1=Junes |last2=Mirzaei |first2=Farzad |last3=Demuth-Eberle |first3=Gabriele J. |last4=Beck |first4=Johannes |last5=Serafin |first5=Michael |date=1997-09-01 |title=η2-Alkynyl and Vinylidene Transition Metal Complexes. 4.1 Reaction of the Metal−Acetylide [(η5-C5H5)(NO)(CO)WC⋮CR]- with Allyl Halides To Give η3-Allyl Complexes. (η1-Alkynyl-η3-allyl)tungsten Complexes: Preparation and Surface-Catalyzed Isomerization |url=https://pubs.acs.org/doi/10.1021/om970070n |journal=Organometallics |volume=16 |issue=18 |pages=3965–3972 |doi=10.1021/om970070n |issn=0276-7333}}

Alkynyl tungsten complexes, along with propargyl tungsten complexes, have applications as templates during synthesis of cyclic compounds like lactones. For instance:

File:Tungsten template synthesis.png

The first tungsten carbene complexes were generated from organolithium reagents and tungsten hexacarbonyl (see the synthesis of Fischer carbenes). Applications include polymerizing alkynes and cyclopropanation of alkenes. Schrock-type tungsten carbene complexes are usually formed via alpha-deprotonation or alpha-elimination of alkyl tungsten complexes. Another synthesis method involves carbene transfer from carbene sources like Wittig's reagent.{{Cite journal |last1=Johnson |first1=Lynda K. |last2=Frey |first2=Marcus |last3=Ulibarri |first3=Tammara A. |last4=Virgil |first4=Scott C. |last5=Grubbs |first5=Robert H. |last6=Ziller |first6=Joseph W. |date=1993-09-01 |title=Alkylidene transfer from phosphoranes to tungsten(IV) imido complexes |url=https://pubs.acs.org/doi/abs/10.1021/ja00071a029 |journal=Journal of the American Chemical Society |volume=115 |issue=18 |pages=8167–8177 |doi=10.1021/ja00071a029 |bibcode=1993JAChS.115.8167J |issn=0002-7863}} Tungsten carbene complexes are active alkene metathesis catalysts.

Tungsten vinylidene complexes (containing the metallaallene unit W=C=CHR) can be generated from alkynyl, carbyne, and alkyne tungsten complexes (see the respective sections of each coumpound). Vinylidene ligands are of strong π acceptor capabilities, therefore enabling catalytic applications of vinylidene complexes in alkyne polymerization reactions.{{Cite journal |last1=Bruneau |first1=Christian |last2=Dixneuf |first2=Pierre H. |date=1999-04-20 |title=Metal Vinylidenes in Catalysis |url=https://pubs.acs.org/doi/10.1021/ar980016i |journal=Accounts of Chemical Research |volume=32 |issue=4 |pages=311–323 |doi=10.1021/ar980016i |issn=0001-4842}}

On a related note, the silylene complexes Cp*W(CO)₂(=SiR₂) can be produced from the photochemical reaction between Cp*W(CO)₃Me and HSiMe₂SiMeR₂, with the exact structure (monomeric/dimeric) dependent on the R group.{{Cite journal |last1=Ueno |first1=Keiji |last2=Asami |first2=Satsuki |last3=Watanabe |first3=Nobuhiko |last4=Ogino |first4=Hiroshi |date=2002-04-01 |title=Synthesis of Self-Stabilized and Donor-Free Silyl(silylene)tungsten Complexes |url=https://pubs.acs.org/doi/abs/10.1021/om020023h |journal=Organometallics |volume=21 |issue=7 |pages=1326–1328 |doi=10.1021/om020023h |issn=0276-7333}}

File:Alpha Hydrogen Exchange.png

Due to electronic effects, tungsten carbyne complexes often adopt slightly bent geometries. Common methods of synthesis involves treating tungsten carbenes of the form W=CXR (X indicates a good leaving group) with Lewis acids or alpha-deprotonation/alpha-dehydrogenation of tungsten carbene complexes. Some primary alkyl tungsten complexes (which may be the product of alkene insertion into W-H bonds) will spontaneously undergo double alpha-dehydrogenation, yielding tungsten carbynes and dihydrogen.{{Cite journal |last1=Shih |first1=Keng-Yu |last2=Totland |first2=Karen |last3=Seidel |first3=Scott W. |last4=Schrock |first4=Richard R. |date=1994-12-01 |title=Spontaneous Loss of Molecular Hydrogen from Tungsten(IV) Alkyl Complexes To Give Alkylidyne Complexes |url=https://pubs.acs.org/doi/abs/10.1021/ja00105a081 |journal=Journal of the American Chemical Society |volume=116 |issue=26 |pages=12103–12104 |doi=10.1021/ja00105a081 |bibcode=1994JAChS.11612103S |issn=0002-7863}}{{Cite journal |last1=Dobbs |first1=Daniel A. |last2=Schrock |first2=Richard R. |last3=Davis |first3=William M. |date=1997-10-15 |title=Reactions of [(Me3SiNCH2CH2)3N]WH with dihydrogen, olefins, acetylenes, carbon monoxide, n-butylisocyanide and azobenzene |url=https://www.sciencedirect.com/science/article/abs/pii/S0020169397056478 |journal=Inorganica Chimica Acta |volume=263 |issue=1 |pages=171–180 |doi=10.1016/S0020-1693(97)05647-8 |issn=0020-1693}} As a result of the reversibility of alpha-dehydrogenation reactions, it's possible to observe the following reaction:

Another preparation method involves the metathesis reaction between the W≡W triple bond (most commonly from W₂(t-BuO)₆) and an alkyne (see the below section on alkyne metathesis). The reaction cannot proceed when the alkyne is diphenylacteylene due to steric hindrance, and instead forming a mixture of W₂(OR)₄(μ-PhC≡CPh)₂ and W₂(OR)₄(μ-CPh)₂. If the C≡C triple bond is replaced with the C≡N of nitriles, then aside form the carbyne product, a nitrido complex containing W≡N shall yield.{{Cite journal |last=Chisholm |first=Malcolm H. |date=1996-01-01 |title=Ditungsten hexaalkoxides: templates for organometallic chemistry and catalysis |url=https://pubs.rsc.org/en/content/articlelanding/1996/dt/dt9960001781 |journal=Journal of the Chemical Society, Dalton Transactions |language=en |issue=9 |pages=1781–1791 |doi=10.1039/DT9960001781 |issn=1364-5447}}{{Cite journal |last1=Listemann |first1=Mark L. |last2=Schrock |first2=Richard R. |date=1985-01-01 |title=Multiple metal carbon bonds. 35. A general route to tri-tert-butoxytungsten alkylidyne complexes. Scission of acetylenes by ditungsten hexa-tert-butoxide |url=https://pubs.acs.org/doi/abs/10.1021/om00120a014 |journal=Organometallics |volume=4 |issue=1 |pages=74–83 |doi=10.1021/om00120a014 |issn=0276-7333}}{{Cite journal |last1=Schrock |first1=Richard R. |last2=Listemann |first2=Mark L. |last3=Sturgeoff |first3=Lynda G. |date=1982-07-01 |title=Metathesis of tungsten-tungsten triple bonds with acetylenes and nitriles to give alkylidyne and nitrido complexes |url=https://pubs.acs.org/doi/abs/10.1021/ja00379a061 |journal=Journal of the American Chemical Society |volume=104 |issue=15 |pages=4291–4293 |doi=10.1021/ja00379a061 |bibcode=1982JAChS.104.4291S |issn=0002-7863}} The exact reaction conditions are detailed in the article on W₂(t-BuO)₆.

Protonation of the carbynes have been documented, yielding an alpha-agostic cationic carbene complex. For W≡C-H complexes, deprotonation is also possible, forming an anion that can react with nucleophiles to form more complex carbyne complexes.{{Cite journal |last1=Enriquez |first1=Alejandro E. |last2=White |first2=Peter S. |last3=Templeton |first3=Joseph L. |date=2001-05-01 |title=Reactions of an Amphoteric Terminal Tungsten Methylidyne Complex |url=https://pubs.acs.org/doi/10.1021/ja0035001 |journal=Journal of the American Chemical Society |volume=123 |issue=21 |pages=4992–5002 |doi=10.1021/ja0035001 |pmid=11457327 |bibcode=2001JAChS.123.4992E |issn=0002-7863}} Due to the electron-deficient nature of the center tungsten atom, it's conceivable that beta-hydrogens of the tungsten carbynes also possess some acidity.

File:Reaction between ethylene and tungsten triple bond.png

The bonding nature of tungsten alkene complexes can be described by the Dewar-Chatt-Duncanson model. Ligand substitution, thermal or photochemical, are most commonly used to prepare such complexes. Norbornadiene complexes (e.g. W(CO)₄(nbd){{Cite journal |last1=Baker |first1=Paul K. |last2=Drew |first2=Michael G. B. |last3=Meehan |first3=Margaret M. |last4=Müller |first4=Jan |date=2002 |title=High Yield Synthesis, Molecular Structure, and Reactions of the 16-Electron Norbornadiene Complex, [WI2(CO)2(nbd)] |url=https://onlinelibrary.wiley.com/doi/10.1002/1521-3749(200208)628:8%3C1727::AID-ZAAC1727%3E3.0.CO;2-A |journal=Zeitschrift für anorganische und allgemeine Chemie |language=en |volume=628 |issue=8 |pages=1727–1729 |doi=10.1002/1521-3749(200208)628:8<1727::AID-ZAAC1727>3.0.CO;2-A |issn=1521-3749}}) have also been reported.

For complexes with double alkene ligands, it's possible to generate a metallacyclopentane complex via reductive coupling, which can be otherwise generated via intramolecular hydrogen transfer between alkyl and vinyl ligands.

File:Orbital interactions of alkyne complexes.png interactions.]]

Alkyne ligands can adopt differing coordination modes with tungsten. Namely, when the tungsten atom is of d₆ configuration (i.e. of low valent), the alkyne ligands are usually 2-electron donors; whereas in d₄ & d₂ configuration tungsten complexes, an additional empty d orbital is available for interaction with the alkyne, therefore the alkyne ligands tend to be 4-electron donors.

Some of tungsten alkyne complexes' reactivity arise from alkynes' role as variable electron donors (i.e. donating between 2 and 4 electrons). This is exemplified in the stepwise oxidation reaction shown below:{{Cite journal |last1=Gunnoe |first1=T. Brent |last2=White |first2=P. S. |last3=Templeton |first3=J. L. |date=1996-01-01 |title=Stepwise Oxidation of Benzylamine Coordinated to the [Tp'W(CO)(PhC2Me)]+ Moiety |url=https://pubs.acs.org/doi/10.1021/ja953944a |journal=Journal of the American Chemical Society |volume=118 |issue=29 |pages=6916–6923 |doi=10.1021/ja953944a |bibcode=1996JAChS.118.6916G |issn=0002-7863}}File:Oxidation tungsten alkyne.pngTungsten complexes can act as templates for the synthesis of chiral alkynes via the reactions of alkyne tungsten complexes followed by alkyne ligand removal.{{Cite journal |last1=Wells |first1=Michael B. |last2=McConathy |first2=Jonathan E. |last3=White |first3=Peter S. |last4=Templeton |first4=Joseph L. |date=2002-11-01 |title=Regioselective and Stereoselective Reactions of 2-Butyne Bound to a Resolved Chiral Tungsten(II) Center |url=https://pubs.acs.org/doi/10.1021/om020416g |journal=Organometallics |volume=21 |issue=23 |pages=5007–5020 |doi=10.1021/om020416g |issn=0276-7333}}

Tungsten alkyne complexes W(CO)_6-n(HC≡CR)_n (n = 1, 2) can be synthesized via photochemical or thermal displacement of carbonyl ligands on tungsten hexacarbonyl (see above). These complexes are unstable and rearrange into vinylidiene complexes of the form W(CO)₅(=C=CHR) via hydrogen migration.{{Cite journal |last1=Szymańska-Buzar |first1=Teresa |last2=Kern |first2=Krystyna |date=2001-03-09 |title=Photosubstitution of carbon monoxide in W(CO)6 by alkyne: NMR detection of thermally unstable alkyne tungsten(0) carbonyl complexes |url=https://www.sciencedirect.com/science/article/abs/pii/S0022328X00008652 |journal=Journal of Organometallic Chemistry |volume=622 |issue=1 |pages=74–83 |doi=10.1016/S0022-328X(00)00865-2 |issn=0022-328X}} This is due to the repulsive interactions between the filled tungsten d orbital and the perpendicular alkyne π orbital. The interaction between the alkyne ligand and the tungsten center is best described in the form of metallacyclopropenes.{{Cite journal |last1=Stegmann |first1=Ralf |last2=Frenking |first2=Gernot |date=1998-05-01 |title=Mechanism of the Acetylene−Vinylidene Rearrangement in the Coordination Sphere of a Transition Metal1 |url=https://pubs.acs.org/doi/10.1021/om980137m |journal=Organometallics |volume=17 |issue=10 |pages=2089–2095 |doi=10.1021/om980137m |issn=0276-7333}}

Electron-withdrawing substituents on alkynes can stabilize alkyne-tungsten complexes (for instance, in the compounds W(CO)₂(L-L)(RC≡CR)₂, where R is an electron-withdrawing group{{Cite journal |last1=Hsiao |first1=Tsung Yu |last2=Kuo |first2=Pei Lung |last3=Lai |first3=Chen Hsing |last4=Cheng |first4=Chien Hong |last5=Cheng |first5=Chih Yi |last6=Wang |first6=Sue Lein |date=1993-04-01 |title=Synthesis, conformational isomerism, and fluxional behavior of octahedral bis(alkyne)tungsten(0) complexes |url=https://pubs.acs.org/doi/abs/10.1021/om00028a026 |journal=Organometallics |volume=12 |issue=4 |pages=1094–1104 |doi=10.1021/om00028a026 |issn=0276-7333}}). This enhances the back-bonding towards the alkyne ligand, while decreasing the electron repulsions (see above paragraph).

One reaction involving tungsten alkyne complexes arises from treating the complex W(L)(PhC≡CPh)₃ with excess diphenylacetylene.{{Cite journal |last1=Yeh |first1=Wen-Yann |last2=Ho |first2=Chi-Lin |last3=Chiang |first3=Michael Y. |last4=Chen |first4=I-Ting |date=1997-06-01 |title=Alkyne−Alkyne Coupling Reactions with W(CO)(PhC⋮CPh)3 and W(NCMe)(PhC⋮CPh)3 |url=https://pubs.acs.org/doi/10.1021/om9702340 |journal=Organometallics |volume=16 |issue=12 |pages=2698–2708 |doi=10.1021/om9702340 |issn=0276-7333}} Reaction products can include tetraphenylcyclobutadiene complexes and pentaphenylcyclopentadienyl complexes as the result of diphenylacetylene coupling:

File:Coupling of diphenylacetylene ligands.png

Related to this is the organotunsgten-catalyzed alkyne trimerization/polymerization, as detailed below in the arene-tungsten complex section.

Tungsten alkyne complexes are susceptible to nucleophilic attack; see the above section on vinyl tungsten complexes.

Tunsgten allyl complexes may be prepared via transmetallation between Grignard reagents. Examples of preparation methods involving the nucleophilic attack on allylic halides can be seen in the above section on alkynyl tungsten. The homoleptic allyl tungsten complex W(C₃H₅)₄ adopts a configuration with S₄ symmetry (see molecular symmetry).{{Cite journal |last1=Landis |first1=Clark |last2=Cleveland |first2=Thomas |last3=Casey |first3=Charles P. |date=1995-03-01 |title=Structures of M(allyl)4 (M = Mo, W, Zr) |url=https://pubs.acs.org/doi/abs/10.1021/ic00109a043 |journal=Inorganic Chemistry |volume=34 |issue=5 |pages=1285–1287 |doi=10.1021/ic00109a043 |issn=0020-1669}}

Some allyl tungsten complexes are synthetically useful, as in:{{Cite web |title=FTO |url=https://chemport-n.cas.org//chemport-n/?APP=ftslink&action=reflink&origin=wiley&version=1.0&coi=1:CAS:528:DyaK2MXis1aitb0%253D&md5=ca3da16b00bacecde7d2b2cd1609529b |access-date=2025-02-19 |website=chemport-n.cas.org}}{{Cite journal |last1=Li |first1=Chien-Le |last2=Liu |first2=Rai-Shung |date=2000-08-01 |title=Synthesis of Heterocyclic and Carbocyclic Compounds via Alkynyl, Allyl, and Propargyl Organometallics of Cyclopentadienyl Iron, Molybdenum, and Tungsten Complexes |url=https://pubs.acs.org/doi/10.1021/cr990283h |journal=Chemical Reviews |volume=100 |issue=8 |pages=3127–3162 |doi=10.1021/cr990283h |pmid=11749315 |issn=0009-2665}}

File:Allyl tungsten synthesis template.png

The other, rather unusual π complexes of tungsten involve the π coordination of the carbonyl group, which almost always coordinate through the lone pair of the carbonyl oxygen atom (σ coordination). One example is TpW(NO)(PMe₃)(η²-DMF), where the nitrogen displays a pyramidal geometry and basicity, indicating loss of conjugation. It can be prepared from the corresponding benzene complex via ligand exchange (see below).

Tungsten cyclobutadiene complexes can be formed via coupling of alkyne ligands, see the above part on tungsten alkyne complexes.

Monomeric tungstenocene is highly unstable and polymerize above 10 kelvin to form a red-brown solid. It's generated via the photolysis of Cp₂WH₂ or the thermolysis of Cp₂W(Me)H and readily inserts into C-H, O-H and B-B bonds.{{Cite journal |last=Green |first=M. L. H. |date=1995-01-01 |title=Recent developments in organometallic chemistry |url=https://www.degruyter.com/document/doi/10.1351/pac199567020249/html |journal=Pure and Applied Chemistry |language=en |volume=67 |issue=2 |pages=249–256 |doi=10.1351/pac199567020249 |issn=1365-3075}}{{Cite journal |last1=Hartwig |first1=John F. |last2=He |first2=Xiaoming |date=1996-02-16 |title=Reactivity of Tungstenocene with BB and BH Bonds versus CH Bonds |url=https://onlinelibrary.wiley.com/doi/10.1002/anie.199603151 |journal=Angewandte Chemie International Edition in English |language=en |volume=35 |issue=3 |pages=315–317 |doi=10.1002/anie.199603151 |issn=0570-0833}} Similarly, the complex [Me₂Si(C₅Me₄)₂]W(Me)H releases methane when heated in benzene, forming the compound [Me₂Si(C₅Me₄)₂]W(Ph)H via a σ-alkane tungsten complex intermediate.{{Cite journal |last1=Chernega |first1=Alexander |last2=Cook |first2=Jessica |last3=Green |first3=Malcolm L. H. |last4=Labella |first4=Luca |last5=Simpson |first5=Stephen J. |last6=Souter |first6=Joanne |last7=Stephens |first7=Adam H. H. |date=1997-01-01 |title=New ansa-2,2-bis(η-cyclopentadienyl)propanemolybdenum and tungsten compounds and intramolecularhydrogen–deuterium exchange in methyl-hydride and ethyl-hydridederivatives |url=https://pubs.rsc.org/en/content/articlelanding/1997/dt/a703725b |journal=Journal of the Chemical Society, Dalton Transactions |language=en |issue=18 |pages=3225–3244 |doi=10.1039/A703725B |issn=1364-5447}} The decaphenyl derivative of tungstenocene, W(C₅Ph₅)₂, can be generated (in its polymeric form) by the coupling of diphenylacteylene ligands, as detailed in the above section on alkyne tungsten complexes. Oxidation into the mono- and di-valent cations are possible.{{Cite journal |last1=Li |first1=Ching-I |last2=Yeh |first2=Wen-Yann |last3=Peng |first3=Shi-Ming |last4=Lee |first4=Gene-Hsiang |date=2001-02-15 |title=Reactivity and electronic property of decaphenylmetallocenes of Mo and W atoms |url=https://www.sciencedirect.com/science/article/abs/pii/S0022328X00008093 |journal=Journal of Organometallic Chemistry |volume=620 |issue=1 |pages=106–112 |doi=10.1016/S0022-328X(00)00809-3 |issn=0022-328X}}

Cp₂WH₂ is a strong Lewis base, forming adducts like [(Cp₂WH₂)₂Ag]BF₄ (which contains hydrogen bridges).{{Cite journal |last1=Brunner |first1=Henri |last2=Muschiol |first2=Manfred |last3=Neuhierl |first3=Thomas |last4=Nuber |first4=Bernhard |date=1998 |title=Silver(I) Complexes with [(C5H5)2MoH2] and [(C5H5)2WH2] Ligands |url=https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/(SICI)1521-3765(199801)4:1%3C168::AID-CHEM168%3E3.0.CO;2-N |journal=Chemistry – A European Journal |language=en |volume=4 |issue=1 |pages=168–171 |doi=10.1002/(SICI)1521-3765(199801)4:1<168::AID-CHEM168>3.0.CO;2-N |issn=1521-3765}} It can be chlorinated with chloroform to form Cp₂WCl₂, and the reverse reaction (which is what is actually used during synthesis) is possible with lithium aluminum hydride. Cp₂WCl₂ itself is made from cyclopentadienide and WCl₄(DME) and can be further oxidized into [Cp₂WCl₂]²⁺.{{Cite journal |last1=Schulz |first1=Axel |last2=Klapötke |first2=Thomas M. |date=1994-10-18 |title=Das perfluortriazinium-kation als oxidationsmittel in der metallorganischen synthese—ein neuer weg zur darstellung von [Cp2MCl2]2+(M = Mo |url=https://www.sciencedirect.com/science/article/abs/pii/0022328X94871183 |journal=Journal of Organometallic Chemistry |volume=480 |issue=1 |pages=195–197 |doi=10.1016/0022-328X(94)87118-3 |issn=0022-328X}} Many other tungstenocene derivatives can be produced from Cp₂WCl₂, like alkyl derivatives using halide metathesis.{{Cite journal |last1=Persson |first1=Christina |last2=Andersson |first2=Carlaxel |date=2002-05-01 |title=WCl4(DME): a facile entry into bis(cyclopentadienyl) complexes of tungsten(IV). Synthesis of bis(cyclopentadienyl)tungsten dihydride |url=https://pubs.acs.org/doi/pdf/10.1021/om00030a055 |access-date=2025-02-19 |journal=Organometallics |volume=12 |issue=6 |pages=2370–2371 |language=EN |doi=10.1021/om00030a055}} Cp₂W(O) can participate in [2+2] cycloaddition reactions.{{Cite journal |last1=Luo |first1=Lubin |last2=Lanza |first2=Giuseppe |last3=Fragalà |first3=Ignazio L. |last4=Stern |first4=Charlotte L. |last5=Marks |first5=Tobin J. |date=1998-04-01 |title=Energetics of Metal−Ligand Multiple Bonds. A Combined Solution Thermochemical and ab Initio Quantum Chemical Study of MO Bonding in Group 6 Metallocene Oxo Complexes |url=https://pubs.acs.org/doi/abs/10.1021/ja971010b |journal=Journal of the American Chemical Society |volume=120 |issue=13 |pages=3111–3122 |doi=10.1021/ja971010b |bibcode=1998JAChS.120.3111L |issn=0002-7863}}

Non-tunsgtenocene derived cyclopentadienyl tunsgeten complexes like Cp*WF₅, Cp*WMe₄, and amide derivatives can be prepared from precursors like Cp*WCl₄.{{Cite journal |last1=Köhler |first1=Katrin |last2=Steiner |first2=Alexander |last3=Roesky |first3=Herbert W. |date=1995-08-01 |title=Die Kristallstrukturen von (η⁵-C₅Me₅)MoMe₄ und (η⁵-C₅Me₅)WMe₄ / The Crystal Structures of (η⁵-C₅Me₅)MoMe₄ and (η⁵-C₅Me₅)WMe₄ |url=https://doi.org/10.1515/znb-1995-0814 |journal=Zeitschrift für Naturforschung B |volume=50 |issue=8 |pages=1207–1209 |doi=10.1515/znb-1995-0814 |issn=1865-7117|doi-access=free }}{{Cite journal |last1=Köhler |first1=Katrin |last2=Herzog |first2=Axel |last3=Steiner |first3=Alexander |last4=Roesky |first4=Herbert W. |date=1996 |title=Synthesis and Structure of the First Cyclopentadienyl(halogeno)metal(VI) Complex of the Chromium Triad [((η5-C5Me5)WF5)] |url=https://onlinelibrary.wiley.com/doi/10.1002/anie.199602951 |journal=Angewandte Chemie International Edition in English |volume=35 |issue=3 |pages=295–297 |doi=10.1002/anie.199602951 |issn=1521-3773}} Trichalcogenide cyclopentadienyl complexes are also known, and notable ones include the chiral complex [Cp*W(O)(S)(Se)]^- (prepared from Cp*W(S)₂Cl){{Cite journal |last1=Kawaguchi |first1=Hiroyuki |last2=Tatsumi |first2=Kazuyuki |date=2001 |title=Synthesis of a Cp* Complex of Tungsten with Three Different Chalcogenido (O2−, S2−, and Se2−) Ligands |url=https://onlinelibrary.wiley.com/doi/10.1002/1521-3757(20010401)113:7%3C1306::AID-ANGE1306%3E3.0.CO;2-4 |journal=Angewandte Chemie |volume=113 |issue=7 |pages=1306–1308 |doi=10.1002/1521-3757(20010401)113:7<1306::AID-ANGE1306>3.0.CO;2-4 |bibcode=2001AngCh.113.1306K |issn=1521-3757}} and the complex [Cp*WS₃]^- (which can be used to synthesize cluster complexes).{{Cite journal |last1=Rau |first1=Melinda S. |last2=Kretz |first2=Christine M. |last3=Geoffroy |first3=Gregory L. |last4=Rheingold |first4=Arnold L. |date=2002-05-01 |title=Reaction of Cp*MoCl4 and Cp*WCl4 with H2O, H2S, amines, and hydrazines. Formation of the trioxo anions [Cp*Mo(O)3]- and [Cp*W(O)3]- and the trisulfido anion [Cp*W(S)3]- |url=https://pubs.acs.org/doi/pdf/10.1021/om00033a015 |access-date=2025-02-20 |journal=Organometallics |volume=12 |issue=9 |pages=3447–3460 |language=EN |doi=10.1021/om00033a015}}{{Cite journal |last1=Rau |first1=Melinda S. |last2=Kretz |first2=Christine M. |last3=Geoffroy |first3=Gregory L. |last4=Rheingold |first4=Arnold L. |last5=Haggerty |first5=Brian S. |date=2002-05-01 |title=New Heterobimetallic .mu.-Oxo Complexes Formed via Halide Displacement Reactions Using the Trioxo Anions [Cp*Mo(O)3]- and [Cp*W(O)3]- |url=https://pubs.acs.org/doi/pdf/10.1021/om00017a020 |access-date=2025-02-20 |journal=Organometallics |volume=13 |issue=5 |pages=1624–1634 |language=EN |doi=10.1021/om00017a020}}{{Cite journal |last1=Lang |first1=Jian-Ping |last2=Ji |first2=Shun-Jun |last3=Xu |first3=Qing-Feng |last4=Shen |first4=Qi |last5=Tatsumi |first5=Kazuyuki |date=2003-06-01 |title=Structural aspects of copper(I) and silver(I) sulfide clusters of pentamethylcyclopentadienyl trisulfido tungsten(VI) and molybdenum(VI) |url=https://linkinghub.elsevier.com/retrieve/pii/S0010854502003090 |journal=Coordination Chemistry Reviews |volume=241 |issue=1 |pages=47–60 |doi=10.1016/S0010-8545(02)00309-0 |issn=0010-8545}}

Of great importance is the applications of cyclopentadienyl tungsten complexes in C-H bond activation.{{Cite journal |last1=Webster |first1=Charles Edwin |last2=Fan |first2=Yubo |last3=Hall |first3=Michael B. |last4=Kunz |first4=Doris |last5=Hartwig |first5=John F. |date=2003-01-01 |title=Experimental and Computational Evidence for a Boron-Assisted, σ-Bond Metathesis Pathway for Alkane Borylation |url=https://pubs.acs.org/doi/abs/10.1021/ja028394c |journal=Journal of the American Chemical Society |volume=125 |issue=4 |pages=858–859 |doi=10.1021/ja028394c |pmid=12537470 |bibcode=2003JAChS.125..858W |issn=0002-7863}} One example is shown below (note that R can stand for both alkyl and aryl groups):

File:Organotungsten C-H activation.png

File:Intramolecular arene tungsten complex.png

The dibenzenechromium analog [W(η⁶-C₆H₆)₂] is a yellow-green substance that has not been extensively studied due to difficult preparation. It is easily oxidized into [W(η⁶-C₆H₆)₂]⁺, and can undergo protonation. Photolysis of tunsgeten hexacarbonyl in acetylene forms benzene and the complex (η⁶-C₆H₆)W(CO)₃ (compare with the diphenylacetylene ligand coupling reaction discussed in the above section on alkyne complexes).{{Cite journal |last1=Szymańska-Buzar |first1=Teresa |last2=Kern |first2=Krystyna |date=2001-03-09 |title=Photosubstitution of carbon monoxide in W(CO)6 by alkyne: NMR detection of thermally unstable alkyne tungsten(0) carbonyl complexes |url=https://www.sciencedirect.com/science/article/abs/pii/S0022328X00008652 |journal=Journal of Organometallic Chemistry |volume=622 |issue=1 |pages=74–83 |doi=10.1016/S0022-328X(00)00865-2 |issn=0022-328X}} Related complexes can catalyze the cyclotrimerization and polymerization of alkynes.{{Cite journal |last1=Vijayaraj |first1=Thorappadi Anantharaj |last2=Sundararajan |first2=Govindarajan |date=1997-10-01 |title=Metathesis Polymerization of Phenylacetylene by Arene Metal Tricarbonyl Complexes Promoted by Chloranil Acceptor |url=https://pubs.acs.org/doi/abs/10.1021/om970192f |journal=Organometallics |volume=16 |issue=22 |pages=4940–4942 |doi=10.1021/om970192f |issn=0276-7333}} Arene complexes deriving from intramolecular ligand interactions are known. For instance, the complex on the right can be generated by reducing the corresponding chloro-complex in the presence of the pyridine ligand.{{Cite journal |last1=Lentz |first1=Margaret R. |last2=Fanwick |first2=Phillip E. |last3=Rothwell |first3=Ian P. |date=2003-05-01 |title=Low-Valent Tungsten Aryloxide Compounds with Pyridine Ancillary Ligation: Intramolecular Reduction of Heterocyclic and Aromatic Rings Including Formation of an η5-Cyclohexadienyl Group |url=https://pubs.acs.org/doi/abs/10.1021/om030054s |journal=Organometallics |volume=22 |issue=11 |pages=2259–2266 |doi=10.1021/om030054s |issn=0276-7333}}

In the unique arene-tungsten complex TpW(NO)(PMe₃)(η²-C₆H₆), the benzene adopts a η² coordination mode.{{Cite journal |last1=Graham |first1=Peter M. |last2=Meiere |first2=Scott H. |last3=Sabat |first3=Michal |last4=Harman |first4=W. Dean |date=2003-10-01 |title=Dearomatization of Benzene, Deamidization of N,N-Dimethylformamide, and a Versatile New Tungsten π Base |url=https://pubs.acs.org/doi/abs/10.1021/om030560h |journal=Organometallics |volume=22 |issue=22 |pages=4364–4366 |doi=10.1021/om030560h |issn=0276-7333}}{{Cite journal |last1=Keane |first1=Joseph M. |last2=Harman |first2=W. Dean |date=2005-04-01 |title=A New Generation of π-Basic Dearomatization Agents |url=https://pubs.acs.org/doi/10.1021/om050029h |journal=Organometallics |volume=24 |issue=8 |pages=1786–1798 |doi=10.1021/om050029h |issn=0276-7333}} Such allows the unusual Diels-Alder reaction of the benzene ligand, which is normally extremely inert in this aspect. The reason behind this activation is related with the strong π backbonding to the arene ligand, localizing the electrons while rendering the bond carbon atoms unreactive (thereby allowing selective reaction of the uncoordinated carbon atoms). Pyridines can be activated in such manners as well, forming isoquinuclidine centers that are biologically significant. The arenes are also activated towards hydrogenation and electrophilic addition. It's worth noting that the tungsten in this case is rather π basic depite the acidic NO⁺ ligand (in fact, without which it would become too basic to be useful), and can form complexes with electron-deficient arenes that are not typically coordinating, such as fluorobenzenes.{{Cite journal |last1=Smith |first1=Jacob A. |last2=Simpson |first2=Spenser R. |last3=Westendorff |first3=Karl S. |last4=Weatherford-Pratt |first4=Justin |last5=Myers |first5=Jeffery T. |last6=Wilde |first6=Justin H. |last7=Dickie |first7=Diane A. |last8=Harman |first8=W. Dean |date=2020-07-13 |title=η2 Coordination of Electron-Deficient Arenes with Group 6 Dearomatization Agents |journal=Organometallics |volume=39 |issue=13 |pages=2493–2510 |doi=10.1021/acs.organomet.0c00277 |issn=0276-7333 |pmc=7810233 |pmid=33456103}}

An synthesis reaction utilizing this type of activation is exemplified below, note that the tungsten can be removed from the substrate oxidatively:

File:Dearomatization synthesis.png

Fullerene can also adopt this curious η² coordination pattern in complexes like W(CO)₃(L-L)(η²-C₆₀), where L-L denotes a bidentate ligand.

The complex [(η⁷-C₇H₃Me₄)W(CO)₃]⁺ can be generated from the corresponding tropylium ion and the complex fac-[W(CO)₃(EtCN)₃]. The CO ligand can be displaced by iodide ions. It is worth noting that the same reaction but with the [C₇Me₇]⁺ cation would yield a η⁵ complex instead (and with an extra EtCN ligand attached) due to repulsion between the methyl groups that hinders planarity of the ligand.{{Cite book |title=Inorganic Chemistry |date=2018 |publisher=Pearson Education, Limited |isbn=978-1-292-13414-7 |edition=5. Auflage |location=Harlow |pages=963–964}}

{{Main|Schrock catalyst}}

File:Tungsten olefin metathesis catalyst.png

The general structure of tungsten-based alkene metathesis catalysts is shown in the image. R₁ is typically methyl or isopropyl, R₂ is usually a bulky group, most commonly -CMe(CF₃)₂, while R₃ is typically a bulky alkyl group, like t-butyl or -CMe₂Ph. They belong to Schrock catalysts, and their activities can be tuned by varying the alkoxide group.{{Cite journal |last1=Schrock |first1=Richard R. |last2=Hoveyda |first2=Amir H. |date=2003 |title=Molybdenum and Tungsten Imido Alkylidene Complexes as Efficient Olefin-Metathesis Catalysts |url=https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.200300576 |journal=Angewandte Chemie International Edition |language=en |volume=42 |issue=38 |pages=4592–4633 |doi=10.1002/anie.200300576 |pmid=14533149 |issn=1521-3773}} It is also possible for the catalysts to act as stoichiometric olefinating reagents on hydroxy ketones (as analogous to Petasis reagent).

Many tungsten-based alkyne metathesis catalysts are of the general type [X₃W≡CR].{{cite journal |last1=Fürstner |first1=Alois |year=2013 |title=Alkyne Metathesis on the Rise |url=https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.201204513 |journal=Angew. Chem. Int. Ed. |volume=52 |issue=10 |pages=2794–3519 |doi=10.1002/anie.201204513 |pmid=23355479}} Activity is manipulated by the ligands. A typical route to such catalysts entails treatment neopentyl Grignard reagent to tungsten(VI) precursor (which involves transmetallation and alpha-deprotonation) followed by net alcoholysis of the alkyl ligands.{{cite journal |last1=Schrock |first1=R. |year=1978 |title=Multiple metal-carbon bonds. 12. Tungsten and molybdenum neopentylidyne and some tungsten neopentylidene complexes |url=https://pubs.acs.org/doi/abs/10.1021/ja00489a049 |journal=J. Am. Chem. Soc. |volume=100 |issue=21 |page=6774 |doi=10.1021/ja00489a049|bibcode=1978JAChS.100.6774C }} Complex 3 can undergo a ligand exchange with lithium salts to generate Schrock type catalysts (complex 4). Another way to make complex 4 is via cleavage of internal alkyne by W(III) complex, such as 5.{{cite book |last1=Chisholm |first1=Malcolm H. |title=Inorganic Syntheses |year=2007 |isbn=9780470132609 |volume=29 |pages=137–140 |chapter=Hexakis(Dimethylamido)Ditungsten and Tungsten(IV) Chloride |doi=10.1002/9780470132609.ch33 |chapter-url=https://onlinelibrary.wiley.com/doi/abs/10.1002/9780470132609.ch33}}{{cite journal |last1=Schrock |first1=R. |year=1982 |title=Metathesis of tungsten-tungsten triple bonds with acetylenes and nitriles to give alkylidyne and nitrido complexes |url=https://pubs.acs.org/doi/abs/10.1021/ja00379a061 |journal=J. Am. Chem. Soc. |volume=104 |issue=15 |page=4291 |doi=10.1021/ja00379a061|bibcode=1982JAChS.104.4291S }} Complex 2, as well as 3, is unable to metathesize internal alkynes, the related pathway is shown right. In detail, compound 6 (when X is not OR) will react with two equivalent alkynes to form complex 7. Complex 7 will undergo an "associative path" to generate a metallabenzene complex 8. It will decompose to polymerized compounds or a cyclopentadienyl complex with a formally reduced tungsten center. Tungstenocenes, or tungsten-containing metallocenes, may be formed from these cyclopentadienyl complexes.

File:Preparation of Schrock catalyst and related transformation.png

The formal 12-electron count of the W(VI) center in Schrock catalyst represents an appreciable Lewis acidity, which seriously limits the scope of these catalysts. For example, Schrock catalyst is unable to metathesize substrates containing donor or basic sites such as amines, thio ethers or crown ether segments. Acid-sensitive groups such as acetals can be destroyed. Replacement of tert-butoxide ligands by fluorinated alkoxides increase the Lewis acidic character. To reach a balance, it is proposed that a heteroleptic push/pull environment around the tungsten center will work.(as shown below){{cite journal |last1=Beer |first1=Stephan |year=2009 |title=Experimental and Theoretical Investigations of Catalytic Alkyne Cross-Metathesis with Imidazolin-2-iminato Tungsten Alkylidyne Complexes |url=https://pubs.acs.org/doi/10.1021/om801119t |journal=Organometallics |volume=28 |issue=5 |page=1534 |doi=10.1021/om801119t}}{{cite journal |last1=Beer |first1=Stephan |year=2007 |title=Efficient Room-Temperature Alkyne Metathesis with Well-Defined Imidazolin-2-iminato Tungsten Alkylidyne Complexes |url=https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.200703184 |journal=Angew. Chem. Int. Ed. |volume=46 |issue=46 |pages=8890–8894 |doi=10.1002/anie.200703184 |pmid=17935104}}{{cite journal |last1=Haberlag |first1=Birte |year=2010 |title=Preparation of Imidazolin-2-iminato Molybdenum and Tungsten Benzylidyne Complexes: A New Pathway to Highly Active Alkyne Metathesis Catalysts |url=https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/chem.201000597 |journal=Chem. Eur. J. |volume=16 |issue=29 |pages=8868–8877 |doi=10.1002/chem.201000597 |pmid=20572182}}{{Cite journal |last1=Wu |first1=Xian |last2=Daniliuc |first2=Constantin G |last3=Hrib |first3=Cristian G |last4=Tamm |first4=Matthias |date=2011 |title=Phosphoraneiminato tungsten alkylidyne complexes as highly efficient alkyne metathesis catalysts |url=https://www.worldcat.org/oclc/4925450605 |journal=Journal of Organometallic Chemistry |language=English |volume=696 |issue=25 |pages=4147–4151 |doi=10.1016/j.jorganchem.2011.06.047 |issn=0022-328X |oclc=4925450605}}{{cite journal |last1=Schrock |first1=R. |year=2007 |title=Facile Synthesis of a Tungsten Alkylidyne Catalyst for Alkyne Metathesis |url=https://pubs.acs.org/doi/abs/10.1021/om0610647 |journal=Organometallics |volume=26 |issue=3 |page=475 |doi=10.1021/om0610647}} For example, complex 13 is highly active (with loading 1-2 mol% being sufficient) and compatible with many functional groups.

{{Gallery|File:Tungsten allene complex.png|A tungsten allene complex, generated from W₂(OCH₂t-Bu)₈ and allenes{{Cite journal |last1=Chisholm |first1=Malcolm H. |last2=Folting |first2=Kirsten |last3=Lynn |first3=Matthew A. |last4=Streib |first4=William E. |last5=Tiedtke |first5=Darin B. |date=1997 |title=Organometallic Chemistry of [W2(OCH2tBu)8] |url=https://onlinelibrary.wiley.com/doi/10.1002/anie.199700521 |journal=Angewandte Chemie International Edition in English |volume=36 |issue=1–2 |pages=52–54 |doi=10.1002/anie.199700521 |issn=1521-3773}}|File:Homoleptic_tungsten_butadiene_complex.png|A homoleptic tungsten butadiene complex of the rare trigonal prismatic geometry|title=|File:Cyclopentadienyl tungsten reaction.png|An unsual reaction involving cyclopentadienyl tunsgten complexes|File:Carbonyl cleavage reaction.png|A reaction that cleaves the carbonyl ligand{{Cite journal |last1=Miller |first1=Rebecca L. |last2=Wolczanski |first2=Peter T. |last3=Rheingold |first3=Arnold L. |date=2002-05-01 |title=Carbide formation via carbon monoxide dissociation across a tungsten-tungsten triple bond |url=https://pubs.acs.org/doi/pdf/10.1021/ja00075a093 |access-date=2025-02-20 |journal=Journal of the American Chemical Society |volume=115 |issue=22 |pages=10422–10423 |language=EN |doi=10.1021/ja00075a093}}}}

• Organochromium chemistry
• Organomolybdenum chemistry

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Category:Organotungsten compounds