Titanium ethoxide

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Titanium ethoxide
Titanium 4 Ethoxide WIKI.png
Abbreviated structure of titanium(IV) ethoxide tetramer. The ethoxide ligands are represented by O's. The terminal ethoxide ligands are designated by Oa, the doubly bridging ligands by Ob, and the triply bridging ligands by Oc.
Names
IUPAC name
ethanolate; titanium(4+)
Preferred IUPAC name
Titanium(IV) ethoxide
Systematic IUPAC name
titanium(4+) tetraethanolate
Other names
Ethyl titanate, tetraethyl titanate
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.019.464 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 221-410-8
PubChem CID
UNII
  • InChI=1S/4C2H5O.Ti/c4*1-2-3;/h4*2H2,1H3;/q4*-1;+4
    Key: JMXKSZRRTHPKDL-UHFFFAOYSA-N
  • CC[O-].CC[O-].CC[O-].CC[O-].[Ti+4]
Properties
C32H80O16Ti4
Molar mass 228.109 g/mol
Appearancecolorless liquid
Density 1.088
Melting point 54 °C (129 °F; 327 K)[ original research? ]
Boiling point 150–152 °C (302–306 °F; 423–425 K) (@10 mmHg)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Titanium ethoxide is a chemical compound with the formula Ti4(OCH2CH3)16. It is a commercially available colorless liquid that is soluble in organic solvents but hydrolyzes readily. Its structure is more complex than suggested by its empirical formula. Like other alkoxides of titanium(IV) and zirconium(IV), it finds used in organic synthesis and materials science. [1]

Contents

Syntheses

Titanium ethoxide is prepared by treating titanium tetrachloride with ethanol in the presence of an amine: [2]

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). [3]

Structure

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. [2] [4] The virtual symmetry of the M4O16 core structure for the tetramer structures of these compounds is C2h. [5]

Titanium methoxide

Like the ethoxide, titanium methoxide Ti(OMe)4 exists as a tetramer with each of the TiIV metal centers having an octahedral coordination environment. [6]

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. [7]

Zirconium ethoxide

Zirconium ethoxide can be prepared in a manner similar but not identical to the titanium compound: [8]

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: [8]

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

Zirconium ethoxide can also be prepared with zirconocene dichloride: [9]

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

Zirconium propoxide

Zr(OnPr)4 also adopts the titanium ethoxide structure. [4] [5]

Reactions

Hydrolysis of Ti alkoxides can be used to deposit TiO2: [10]

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. [11] Intermediates in the hydrolysis have been crystallized. They feature interior oxides in addition to the ethoxide on the exterior of the clusters. [12]

The high reactivity of titanium ethoxide toward water is exploited in its use in condensation reactions. [13]

Related Research Articles

A Ziegler–Natta catalyst, named after Karl Ziegler and Giulio Natta, is a catalyst used in the synthesis of polymers of 1-alkenes (alpha-olefins). Two broad classes of Ziegler–Natta catalysts are employed, distinguished by their solubility:

<span class="mw-page-title-main">Transition metal alkoxide complex</span> Conjugate base of an alcohol

A transition metal alkoxide complex is a kind of coordination complex containing one or more alkoxide ligands, written as RO−, where R is the organic substituent. Metal alkoxides are used for coatings and as catalysts.

<span class="mw-page-title-main">Titanium tetrachloride</span> Inorganic chemical compound

Titanium tetrachloride is the inorganic compound with the formula TiCl4. It is an important intermediate in the production of titanium metal and the pigment titanium dioxide. TiCl4 is a volatile liquid. Upon contact with humid air, it forms thick clouds of titanium dioxide and hydrochloric acid, a reaction that was formerly exploited for use in smoke machines. It is sometimes referred to as “tickle” or “tickle 4”, as a phonetic representation of the symbols of its molecular formula.

<span class="mw-page-title-main">Hafnium tetrachloride</span> Chemical compound

Hafnium(IV) chloride is the inorganic compound with the formula HfCl4. This colourless solid is the precursor to most hafnium organometallic compounds. It has a variety of highly specialized applications, mainly in materials science and as a catalyst.

<span class="mw-page-title-main">Titanocene dichloride</span> Chemical compound

Titanocene dichloride is the organotitanium compound with the formula (η5-C5H5)2TiCl2, commonly abbreviated as Cp2TiCl2. This metallocene is a common reagent in organometallic and organic synthesis. It exists as a bright red solid that slowly hydrolyzes in air. It shows antitumour activity and was the first non-platinum complex to undergo clinical trials as a chemotherapy drug.

<span class="mw-page-title-main">Zirconium(IV) chloride</span> Chemical compound

Zirconium(IV) chloride, also known as zirconium tetrachloride, is an inorganic compound frequently used as a precursor to other compounds of zirconium. This white high-melting solid hydrolyzes rapidly in humid air.

Titanium(III) chloride is the inorganic compound with the formula TiCl3. At least four distinct species have this formula; additionally hydrated derivatives are known. TiCl3 is one of the most common halides of titanium and is an important catalyst for the manufacture of polyolefins.

<span class="mw-page-title-main">Borohydride</span>

Borohydride refers to the anion [BH4]−, which is also called tetrahydridoborate, and its salts. Borohydride or hydroborate is also the term used for compounds containing [BH4−nXn]−, where n is an integer from 0 to 3, for example cyanoborohydride or cyanotrihydroborate [BH3(CN)]− and triethylborohydride or triethylhydroborate [BH(CH2CH3)3]−. Borohydrides find wide use as reducing agents in organic synthesis. The most important borohydrides are lithium borohydride and sodium borohydride, but other salts are well known. Tetrahydroborates are also of academic and industrial interest in inorganic chemistry.

<span class="mw-page-title-main">Organotitanium chemistry</span>

Organotitanium chemistry is the science of organotitanium compounds describing their physical properties, synthesis, and reactions. Organotitanium compounds in organometallic chemistry contain carbon-titanium chemical bonds. They are reagents in organic chemistry and are involved in major industrial processes.

<span class="mw-page-title-main">Titanium isopropoxide</span> Chemical compound

Titanium isopropoxide, also commonly referred to as titanium tetraisopropoxide or TTIP, is a chemical compound with the formula Ti{OCH(CH3)2}4. This alkoxide of titanium(IV) is used in organic synthesis and materials science. It is a diamagnetic tetrahedral molecule. Titanium isopropoxide is a component of the Sharpless epoxidation, a method for the synthesis of chiral epoxides.

<span class="mw-page-title-main">Tetrakis(dimethylamido)titanium</span> Chemical compound

Tetrakis(dimethylamino)titanium (TDMAT), also known as Titanium(IV) dimethylamide, is a chemical compound. The compound is generally classified as a metalorganic species, meaning that its properties are strongly influenced by the organic ligands but the compound lacks metal-carbon bonds. It is used in chemical vapor deposition to prepare titanium nitride (TiN) surfaces and in atomic layer deposition as a titanium dioxide precursor. The prefix "tetrakis" refers the presence of four of the same ligand, in this case dimethylamides.

<span class="mw-page-title-main">Sodium cyclopentadienide</span> Chemical compound

Sodium cyclopentadienide is an organosodium compound with the formula C5H5Na. The compound is often abbreviated as NaCp, where Cp− is the cyclopentadienide anion. Sodium cyclopentadienide is a colorless solid, although samples often are pink owing to traces of oxidized impurities.

Organovanadium chemistry is the chemistry of organometallic compounds containing a carbon (C) to vanadium (V) chemical bond. Organovanadium compounds find only minor use as reagents in organic synthesis but are significant for polymer chemistry as catalysts.

In organometallic chemistry, bent metallocenes are a subset of metallocenes. In bent metallocenes, the ring systems coordinated to the metal are not parallel, but are tilted at an angle. A common example of a bent metallocene is Cp2TiCl2. Several reagents and much research is based on bent metallocenes.

<span class="mw-page-title-main">Niobium(V) ethoxide</span> Chemical compound

Niobium(V) ethoxide is an metalorganic compound with formula Nb2(OC2H5)10. It is a colorless liquid that dissolves in some organic solvents but hydrolyzes readily. It is mainly used for the sol-gel processing of materials containing niobium oxides.

<span class="mw-page-title-main">Tantalum(V) ethoxide</span> Chemical compound

Tantalum(V) ethoxide is a metalorganic compound with formula Ta2(OC2H5)10, often abbreviated as Ta2(OEt)10. It is a colorless solid that dissolves in some organic solvents but hydrolyzes readily. It is used to prepare films of tantalum(V) oxide.

<span class="mw-page-title-main">(Cyclopentadienyl)titanium trichloride</span> Chemical compound

(Cyclopentadienyl)titanium trichloride is an organotitanium compound with the formula (C5H5)TiCl3. It is a moisture sensitive orange solid. The compound adopts a piano stool geometry.

<span class="mw-page-title-main">Hafnocene dichloride</span> Chemical compound

Hafnocene dichloride is the organohafnium compound with the formula (C5H5)2HfCl2. It is a white solid that is sparingly soluble in some organic solvents. The lighter homologues zirconacene dichloride and titanocene dichloride have received much more attention. While hafnocene is only of academic interest, some more soluble derivatives are precatalysts for olefin polymerization. Moreso than the Zr analogue, this compound is highly resistant to reduction.

The +4 oxidation state dominates titanium chemistry, but compounds in the +3 oxidation state are also numerous. Commonly, titanium adopts an octahedral coordination geometry in its complexes, but tetrahedral TiCl4 is a notable exception. Because of its high oxidation state, titanium(IV) compounds exhibit a high degree of covalent bonding.

References

  1. ↑ Ram C. Mehrotra; Singh, Anirudh (1997). "Recent Trends in Metal Alkoxide Chemistry". In Kenneth D. Karlin (ed.). Progress in Inorganic Chemistry. Vol. 46. John Wiley & Sons. pp. 239–454. doi:10.1002/9780470166475.ch4. ISBN   978-0-470-16704-5.
  2. 1 2 F. Albert Cotton; Geoffrey Wilkinson; Murillo, C.; Bochmann, M. (1999). Advanced Inorganic Chemistry (6th ed.). New York: John Wiley & Sons. ISBN   978-0-471-19957-1.
  3. ↑ Integrated Spectral Database System of Organic Compounds, version 2011. AIST: Japan, 2011 (accessed October 3rd, 2011).
  4. 1 2 James A. Ibers (1963). "Crystal and Molecular Structure of Titanium(IV) Ethoxide". Nature . 197 (4868): 686–687. Bibcode:1963Natur.197..686I. doi:10.1038/197686a0. S2CID   4297907.
  5. 1 2 Day, Victor W.; Klemperer, Walter G.; Pafford, Margaret M. (2001). "Isolation and Structural Characterization of Tetra-n-propyl Zirconate in Hydrocarbon Solution and the Solid State". Inorg. Chem. 40 (23): 5738–5746. doi:10.1021/ic010776g. PMID   11681880.
  6. ↑ Wright, D. A.; Williams, D. A. (1968). "The Crystal and Molecular Structure of Titanium Tetramethoxide". Acta Crystallographica B . 24 (8): 1107–1114. Bibcode:1968AcCrB..24.1107W. doi:10.1107/S0567740868003766.
  7. ↑ Ghosh, Rajshekhar; Nethaji, Munirathinam; Samuelson, Ashoka G. (2005). "Reversible double insertion of aryl isocyanates into the Ti–O bond of titanium(IV) isopropoxide". J. Organomet. Chem. 690 (5): 1282–1293. doi:10.1016/j.jorganchem.2004.11.038.
  8. 1 2 Bradley, D. C.; Wardlaw, W. (1951). "Zirconium alkoxides". J. Chem. Soc. : 280–285. doi:10.1039/jr9510000280.
  9. ↑ Gray, Donald R.; Brubaker, Carl H. (1971). "Preparation and characterization of a series of chloroalkoxobis(cyclopentadienyl)zirconium(IV) and dialkoxobis(cyclopentadienyl)zirconium(IV) compounds". Inorg. Chem. 10 (10): 2143–2146. doi:10.1021/ic50104a010.
  10. ↑ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN   978-0-08-037941-8.
  11. ↑ Schubert, U. (2003). "Sol–Gel Processing of Metal Compounds". In McCleverty, J. A.; Meyer, T. J. (eds.). Comprehensive Coordination Chemistry II. Reference Module in Chemistry, Molecular Sciences and Chemical Engineering. Vol. 7. Pergamon. pp. 629–656. doi:10.1016/B0-08-043748-6/06213-7. ISBN   978-0-12-409547-2.
  12. ↑ Coppens, Philip; Chen, Yang; Trzop, Elżbieta (2014). "Crystallography and Properties of Polyoxotitanate Nanoclusters". Chemical Reviews. 114 (19): 9645–9661. doi:10.1021/cr400724e. PMID   24820889.
  13. ↑ Mackey, Pamela; Cano, Rafael; Foley, Vera M.; McGlacken, Gerard P. (2017). "Preparation of anti-1,3-Amino Alcohol Derivatives Through an Asymmetric Aldol-Tishchenko Reaction of Sulfinimines". Organic Syntheses. 94: 259–279. doi: 10.15227/orgsyn.094.0259 .
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