THE ALKOXIDES OF ZIRCONIUM AND HAFNIUM - DIRECT ELECTROCHEMICAL SYNTHESIS AND MASS-SPECTRAL STUDY - DO M(OR)(4), WHERE M=ZR, HF, SN, REALLYEXIST

The direct electrochemical synthesis of zirconium (la) and hafnium (Ib ) alkoxides, M(OPri)(4) . (PrOH)-O-i, Zr(OBu(i))(4) . Bu(i)OH (4a) and M(OR)(4), where R = Et (2a,b), Bu(n) (3a), Bu(S) (5a), C(2)H(4)OMe (6 a,b) has been carried out by anodic oxidation of metals in anhydrous a lcohols in the presence of LiCl as a conductive additive to give quant itative yields. The solubility polytherms and dissociation pressure of la,b have been investigated. It has been proved by means of chemical analysis, X-ray powder, and IR spectral studies that the desolvation o f 1a,b and Sn(OPri)(4) . (PrOH)-O-i (1c) is accompanied by the formati on of amorphous oxocompounds M(3)O(OPri)(10). On the basis of H-1 NMR data it has been proved that the structure of the latter is analogous to that of known triangular cluster molecules M(3)(mu(3)-O)(mu(3)-OR)( mu-OR)(3)(OR)(6), where M = Mo, W, U. Mass-spectral data and the deter mined physicochemical characteristics of 1-5 permit to conclude that t he samples of composition M(OR)(4), where M = Zr, Hf, and 2, 3, 5 cont ain tri- and tetranuclear oxocomplexes M(3)O(OR)(10) and M(4)O(OR)(14) , respectively, along with Zr(OR)(4) oligomers of different molecular complexity.