X-RAY CRYSTALLOGRAPHIC ANALYSIS OF THE OXYTELLURIUM COMPOUNDS [10-TE-4(C3O)] AND SOLVENT EFFECT ON THE HYPERVALENCY

2,2'-Biphenylylene-2-biphenylylphenoxytellurane derivatives ([10-Te-4( C3O)]) having an o- or p-substituted phenoxy group RPhO- (2a, R = Me; 2b, R = H; 2c, R = Cl; 2d, R = MeOCO; 2e, MeCO; 2f, R = NO2; 2g, R = 2 ,4,6-Cl-3) were synthesized by the reaction of bis(2,2'-biphenylylene) tellurane with the corresponding phenol derivatives. The compounds 2f, g were subjected to X-ray crystallographic analysis which revealed tha t their structures are distorted trigonal bipyramids or typical tellur onium salts. The hypervalency of the tellurium compounds in solution w as estimated by correlating their Te-125 NMR chemical shifts and the G utmann donor number, DN, employed in the experiments.