:Titanocene pentasulfide
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| verifiedrevid =
| ImageFile = Cp2TiS5imp.png
| ImageSize = 150px
| IUPACName =
| OtherNames = titanocene pentasulfide
|Section1={{Chembox Identifiers
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo = 12116-82-4
| ChemSpiderID = 57542900
| PubChem=92000650
| StdInChI=1S/2C5H5.H2S5.Ti/c2*1-2-4-5-3-1;1-3-5-4-2;/h2*1-5H;1-2H;/q2*-1;;+4/p-2
| StdInChIKey = JDSOAGYVYGEMJJ-UHFFFAOYSA-L
| SMILES = [CH-]1C=CC=C1.[CH-]1C=CC=C1.S1SSSS[Ti2+]1
}}
|Section2={{Chembox Properties
| Formula = C10H10S5Ti
| MolarMass = 338.382
| Appearance = red solid
| Density =
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|Section3={{Chembox Structure
| Coordination = Dist. tetrahedral
| CrystalStruct =
| Dipole =
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|Section7={{Chembox Hazards
| ExternalSDS =
| NFPA-H =
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|Section8={{Chembox Related
| OtherCompounds = Zirconocene pentasulfide
Titanocene dichloride}}
}}
Titanocene pentasulfide is the organotitanium compound with the formula (C5H5)2TiS5, commonly abbreviated as Cp2TiS5. This metallocene exists as a bright red solid that is soluble in organic solvents. It is of academic interest as a precursor to unusual allotropes of elemental sulfur as well as some related inorganic rings.
Preparation and structure
Titanocene pentasulfide is prepared by treating Cp2TiCl2 with polysulfide salts:{{cite book|first1=Alan |last1=Shaver |first2=James M. |last2=McCall |first3=Gabriela |last3=Marmolejo |title=Inorganic Syntheses |chapter=Cyclometallapolysulfanes (And Selanes) of Bis(η 5 -Cyclopentadienyl) Titanium(IV), Zirconium(IV), Molybdenum(IV), and Tungsten(IV) |series=Inorg. Synth. |date=1990 |volume=27 |pages=59–65 |doi=10.1002/9780470132586.ch11|isbn=978-0-470-13258-6 }} It was first produced by the addition of elemental sulfur to titanocene dicarbonyl:{{cite journal|title=π-Complexes of Group IVA metals with cyclopentadiene, indene, and fluorine |journal=Bull. Soc. Chim. France |date=1966 |volume= 11 |pages= 3548–64}}
:(C5H5)2Ti(CO)2 + {{frac|5|8}} S8 → (C5H5)2TiS5 + 2 CO
The complex is viewed as a pseudotetrahedral complex of Ti(IV). The Ti–S distances are 2.420 and 2.446 Å and the S–S bond distances are of a normal range, 2.051–2.059 Å.{{cite journal|first1=E. F. |last1=Epstein |first2=I. |last2=Bernal |title=Pentachalcogenide dianions in transition-metal complexes: crystal structure of bis-(π-cyclopentadienyl)titanium pentasulphide |journal=J. Chem. Soc. D |date=1970| volume=1970|issue=7 |pages=410–411|doi=10.1039/C29700000410}} The molecule exhibits a dynamic NMR spectrum owing to the chair–chair equilibrium of the TiS5 ring which equivalizes the Cp signals at high temperatures.{{cite journal|first1=Alan |last1=Shaver |first2=James M. |last2=McCall |title=Preparation and Variable-Temperature NMR Studies of the Metallacyclosulfanes Cp2MS5 and (MeSCp)MS3, Where M = Ti, Zr, and Hf| journal=Organometallics |date=1984 |volume= 3 |issue=12 |pages= 1823–1829 | doi = 10.1021/om00090a008 }}
Reactions
Cp2TiS5 reacts with sulfur and selenium chlorides, ExCl2, to afford titanocene dichloride and various S5+x and S5Sex rings. Illustrative is the synthesis of S7 from disulfur dichloride:{{cite journal |title = Solid Sulfur Allotropes Sulfur Allotropes| first1 = Ralf |last1 = Steudel|first2 = Bodo|last2 = Eckert|journal = Topics in Current Chemistry |year = 2003 |volume = 230 |pages = 1–80 |doi = 10.1007/b12110}}
:(C5H5)2TiS5 + S2Cl2 → (C5H5)2TiCl2 + S7
It also reacts with alkenes and ketenes to give heterocycles composed of Ti, C and S. With trialkylphosphines, the cycle dimerize into rings of various sizes, depending on the trialkylphosphine used.{{cite book
| title = Advanced Inorganic Chemistry |edition=6th
| first1 = F. Albert |last1=Cotton
| first2 = Geoffrey |last2=Wilkinson
| first3 = Carlos A. |last3=Murillo
| first4 = Manfred |last4=Bochmann
| publisher = Wiley
| year = 1999
| isbn = 978-0-471-19957-1
}}
References
{{reflist}}
{{Titanium compounds}}
{{Cyclopentadienide complexes}}