Some aliphatic and aromatic hydroxy ester derivatives of niobium and tantalum

Reactions of niobium and tantalum pentaethoxides with ethyl-1-hydroxycyclohexylacetate (HECA), ethyl 2-hydroxy-2-arylpropionate (HEAP) and ethyl 2-hydroxy-2-aryl butyrate (HEAB) lead to compounds of the type [M(OEt)5−n(L)n] (where M=Nb or Ta; n=1, 2 or 3; and L=HECA, HEAP or HEAB). These were characterised by elemental analysis, molecular weight determinations and i.r. and n.m.r. spectral studies. Alcoholysis reactions witht-butanol were also carried out.