Oxy- and thio-phosphorus acid derivatives of tin(IV). The crystal and molecular structure of O-methylmethylphosphatotriphenyltin(IV)

Article abstract of DOI:10.1016/0022-328X(90)87145-4

O-Methylmethylphosphatotriphenyltin(IV) (II) is synthesized by treating stoichiometric amounts of O,O'-dimethylmonothiophosphatotriphenyltin(IV) (I) with mercury.The negative 119Sn chemical shift in solution relative to tetramethyltin for I corresponds to higher than four coordination (at tin) in solution.The values of the 119Sn Moessbauer isomer shift for I and II confirm the presence of tin as tin(IV).The magnitudes of the quadrupole splitting and the ratios of the QS to the IS of both compounds reveal that tin is higher than four coordinated.The solid state structure of II was determined by X-ray diffraction.The compound crystallized in the trigonal space group R3<*> with a, b 31433(15), c 10.259(3) Angstroem, V 8778.2 Angstroem³, Z = 18, D_x 1.56 g cm^-3 at 138 K.In the solid state compound II exists as a highly symmetric cyclic hexamer in which planar trimethyltin(IV) groups are axially bridged by O-P-O linkages.The geometry about tin is trigonal bipyramidal with an axial O-Sn-O angle of 177.1(2) deg and average C-Sn-C angle of 120.0(2) deg.The structure of the hexameric ring is linear at tin but bent at phosphorus with an O-P-O angle of 117.1(2) deg.