:Titanium ethoxide

Titanium ethoxide is prepared by treating titanium tetrachloride with ethanol in the presence of an amine:{{cite book|author1=F. Albert Cotton|author-link=F. Albert Cotton|author2 = Geoffrey Wilkinson|author2-link = Geoffrey Wilkinson|last3 = Murillo|first3 = C.|last4 = Bochmann|first4 = M.|title = Advanced Inorganic Chemistry|edition = 6th|publisher = John Wiley & Sons|location = New York|year = 1999|isbn = 978-0-471-19957-1}}

:TiCl₄ + 4 EtOH + 4 Et₃N → Ti(OEt)₄ + 4 Et₃NHCl

The purity of titanium ethoxide is commonly assayed by proton NMR spectroscopy. Ti(OEt)₄ 1H NMR (90 MHz, chloroform-d, ppm): 4.36 (quartet, 8H, CH₂), 1.27 (triplet, 12H, CH₃).Integrated Spectral Database System of Organic Compounds, version 2011. AIST: Japan, 2011 (accessed October 3rd, 2011).

Both Ti(OEt)₄ exist mainly as tetramers with an octahedral coordination environment around the metal centers. There are two types of titanium centers, depending on the number of terminal vs bridging alkoxide ligands. Zr(OEt)₄ is structurally similar.{{cite journal | author = James A. Ibers | author-link = James A. Ibers | title = Crystal and Molecular Structure of Titanium(IV) Ethoxide | journal = Nature | year = 1963 | volume = 197 | doi = 10.1038/197686a0 | issue = 4868 | pages = 686–687 | bibcode = 1963Natur.197..686I| s2cid = 4297907 }} The virtual symmetry of the M₄O₁₆ core structure for the tetramer structures of these compounds is C_2h.

Like the ethoxide, titanium methoxide Ti(OMe)₄ exists as a tetramer with each of the Ti^IV metal centers having an octahedral coordination environment.{{cite journal | title = The Crystal and Molecular Structure of Titanium Tetramethoxide | last1 = Wright | first1 = D. A. | last2 = Williams | first2 = D. A. | journal = Acta Crystallographica B | year = 1968 | volume = 24 | issue = 8 | pages = 1107–1114 | doi=10.1107/S0567740868003766| doi-access = | bibcode = 1968AcCrB..24.1107W }}

{{main|Titanium isopropoxide}}

With bulky alkyl groups, Ti(OⁱPr)₄ in contrast exist as a monomer with a tetrahedral environment around the Ti center. This lower degree of coordination to the metal center is attributed to the steric bulk of the ⁱPr groups versus the n-alkyl groups, this serves to prevent bridging interactions between the metal centers.{{cite journal | doi = 10.1016/j.jorganchem.2004.11.038 | title = Reversible double insertion of aryl isocyanates into the Ti–O bond of titanium(IV) isopropoxide | year = 2005 | last1 = Ghosh | first1 = Rajshekhar | last2 = Nethaji | first2 = Munirathinam | last3 = Samuelson | first3 = Ashoka G. | journal = J. Organomet. Chem. | volume = 690 | issue = 5 | pages = 1282–1293}}

Zirconium ethoxide can be prepared in a manner similar but not identical to the titanium compound:{{cite journal | last1 = Bradley | first1 = D. C. | authorlink1 = Donald Charlton Bradley | last2 = Wardlaw | first2 = W. | journal = J. Chem. Soc. | year = 1951 | pages = 280–285 | doi = 10.1039/jr9510000280 | title = Zirconium alkoxides}}

:ZrCl₄ + 5 NaOEt + EtOH → NaH[Zr(OEt)₆] + 4 NaCl

:NaH[Zr(OEt)₆] + HCl → Zr(OEt)₄ + NaCl + 2 EtOH

A more common synthesis for zirconium ethoxide is to treat zirconium tetrachloride with the desired alcohol and ammonia:

:ZrCl₄ + 4 ROH + 4 NH₃ → Zr(OR)₄ + 4 NH₄Cl

Zirconium ethoxide can also be prepared with zirconocene dichloride:{{cite journal | last1 = Gray | first1 = Donald R. | last2 = Brubaker | first2 = Carl H. | journal = Inorg. Chem. | year = 1971 | volume = 10 | issue = 10 | pages = 2143–2146 | doi = 10.1021/ic50104a010 | title = Preparation and characterization of a series of chloroalkoxobis(cyclopentadienyl)zirconium(IV) and dialkoxobis(cyclopentadienyl)zirconium(IV) compounds}}

:Cp₂ZrCl₂ + 4 EtOH + 2 Et₃N → 2 CpH + 2 Et₃NHCl + Zr(OEt)₄

Zr(OⁿPr)₄ also adopts the titanium ethoxide structure.{{cite journal | doi = 10.1021/ic010776g | title = Isolation and Structural Characterization of Tetra-n-propyl Zirconate in Hydrocarbon Solution and the Solid State | year = 2001 | last1 = Day | first1 = Victor W. | last2 = Klemperer | first2 = Walter G. | last3 = Pafford | first3 = Margaret M. | journal = Inorg. Chem. | volume = 40 | issue = 23 | pages = 5738–5746 | pmid = 11681880}}

Hydrolysis of Ti alkoxides can be used to deposit TiO₂:{{Greenwood&Earnshaw2nd}}

:Ti(OEt)₄ + 2 H₂O → TiO₂ + 4 EtOH

The course of the hydrolysis is affected by the presence of base or acid catalysts for the hydrolysis. Generally acid-catalysis yields a sol where the polymer chains are randomly oriented and linear. In the base-mediated case bushy clusters or crosslinked networks are produced, these structures can trap solvent and reaction byproducts and form a gel coating. This is the sol-gel process. {{cite book|first = U.|last = Schubert|chapter = Sol–Gel Processing of Metal Compounds|editor1-first = J. A.|editor1-last = McCleverty|editor2-first = T. J.|editor2-last = Meyer|title = Comprehensive Coordination Chemistry II|series = Reference Module in Chemistry, Molecular Sciences and Chemical Engineering|year = 2003|pages = 629–656|volume = 7|publisher = Pergamon|doi = 10.1016/B0-08-043748-6/06213-7|isbn = 978-0-12-409547-2}} Intermediates in the hydrolysis have been crystallized. They feature interior oxides in addition to the ethoxide on the exterior of the clusters.{{cite journal |doi=10.1021/cr400724e|title=Crystallography and Properties of Polyoxotitanate Nanoclusters|year=2014|last1=Coppens|first1=Philip|last2=Chen|first2=Yang|last3=Trzop|first3=Elżbieta|journal=Chemical Reviews|volume=114|issue=19|pages=9645–9661|pmid=24820889}}

The high reactivity of titanium ethoxide toward water is exploited in its use in condensation reactions.{{cite journal |doi=10.15227/orgsyn.094.0259 |title=Preparation of anti-1,3-Amino Alcohol Derivatives Through an Asymmetric Aldol-Tishchenko Reaction of Sulfinimines |date=2017 |journal=Organic Syntheses |volume=94 |pages=259–279|first1=Pamela|last1=Mackey|first2=Rafael|last2=Cano|first3=Vera M.|last3=Foley|first4= Gerard P.|last4=McGlacken |doi-access=free}}

{{Reflist}}

{{Titanium compounds}}

Category:Ethoxides

Category:Titanium(IV) compounds