Synthesis of tris(2,4,6-trimethylphenyl) hydroxoantimony carboxylates. Crystal structure of tris(2,4,6-trimethylphenyl) hydroxoantimony 1-adamantylcarboxylate

The tris(2,4,6-trimethylphenyl)hydroxoantimony carboxylates Mes3Sb(OH)-OOCR · nH2O (n = 1, Mes = 2,4,6-Me3C6H2, R = H, CH2F; n = 0, R = CH3, CHCl2, CF3, C10H15 = 1-adamantyl) have been obtained by neutralization of tris-(2,4,6-trimethylphenyl)antimony dihydroxide with the appropriate carboxylic acid. The crystal structure of tris(2,4,6-trimethylphenyl)hydroxoantimony 1-adamantyl-carboxylate has been determined by single crystal X-ray diffraction. Antimony is in a slightly distorted trigonal bipyramidal environment, with the unidentate carboxylate group and OH being in apical positions. The SbO(H) bond length, 202.6(3) pm, is appreciably shorter than the usual value for SbO(carboxylate) bond, viz. 212.1(3) pm in tris(2,4,6-trimethylphenyl)-hydroxoantimony 1-adamantyl-carboxylate. From IR data analogous molecular structures are inferred for the other compounds Mes3Sb(OH)O2CR · nH2O. The water in Mes3Sb(OH)O2CR · H2O (R = H, CH2F) is assumed to be water of crystallization.