Tin(IV) and organotin(IV) derivatives of novel β-diketones. III Diorgano- and dihalotin(IV) complexes of 1,3-dimethyl-4-R(CO)-pyrazol-5-one (R=CH3, C6H5) and the crystal structure of trans-dicyclohexylbis(1,3-dimethyl-4-acetylpyrazolon-5-ato)tin(IV)

Abstract Several diorgano- and dihalotin(IV) derivatives of new β -diketonate donors, 1,3-dimethyl-4-R(CO)pyrazol-5-ones (R=Me, Q D H; R=Ph, Q M H) have been synthesized and characterized with analytical and spectroscopic methods. They are stable monomeric species, very soluble not only in aromatic and chlorohydrocarbon solvents, but also in alcohols and hydroalcoholic solutions. In the solid state, the diorganotin(IV) derivatives adopt a skewed trapezoidal bipyramidal geometry. The X-ray structure of bis(1,3-dimethyl-4-acetylpyrazolon-5-ato)dicyclohexyltin(IV) shows marked distortion of the organometallic C–Sn–C angle (155°) and two different sets of Sn–O distances. The factors affecting the distortion of this type of complex are discussed. The dihalotin(IV) derivatives (Q) 2 SnX 2 (X=F, Cl, Br and I) are likely cis octahedral in the solid state, whereas in solution they exist as a mixture of cis and trans isomers. 119 Sn-NMR solution data are discussed and related to electronic and steric properties of the β -diketonate donor, and also to the nature of the halo and organic groups bound to tin.