Gallium, indium, and thallium alkoxides

Studies of the alkoxides of this group started in the middle of 1960s when Funk [602], Mehrotra [1129], and Reinmann [1349] nearly simultaneously reported the synthesis of Ga(OR)j. Indium isopropoxide was first described by Mehrotra in 1972 [1106] (the preparation ofIn(OMe)3 on reaction of InC13 with 50 equivalents of NaOMe reported by Runge et al. [1374] should apparently be questioned). Of the modem studies of primary interest are the preparation of indium (I) phenoxides stabilized by bulky ligands, reported by Roesky etal. [1362,1434], and that of the bimetallic butoxide, In Sn(OBu )3, described byVeith etal. [1685], 

In the molecules of [InOAr]2 and InSn(OBu )j the indium atoms display a /-triangular coordination [ ln 02]. 

Concerning the application of gallium alkoxides, one can mention the selective catalytic activity of Ga(OPh)3in the condensation reactions of isobutene with phenols. In(OR)3 is used for the preparation of solutions for production of ln203 and In2Oj-related conduction films [1618] and also in the synthesis of volatile precursors for MOCVD deposition of In2Oj [830]. 

In contrast to its analogs, thallium forms the homoleptic alkoxides only in a +1 oxidation state (the trivalent derivatives are known only as TlR OR Jj ). The TIOR homologous series is represented by a considerable number of derivatives that has been studied for 140 years. A number of them were first synthesized along with the other main derivatives of thallium in 1860s by Lamy [988], who discovered this element (simultaneously with Crookes). TIOEt was isolated as a viscous oil that separates from solution on dissolution of TlOH in hot EtOH. TIOMe crystallizes on action of MeOH on the ethoxide. The easily accessible ethoxide has become the most useful reactant in the synthesis of other inorganic and organic derivatives of T1(I). 

The heats of these reactions are given in the works of Forcrand [182,1191]. 

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