Solvent effects on interaction between Palladium(II) diacetate and electron donors

The state of palladium diacetate in crystals and solutions in dichloroethan e, benzene, dioxane, and tetrahydrofuran is considered based on X-ray struc ture analysis and cryoscopy data, IR spectral studies, and dipole moment me asurements in these media. The enthalpies of formation of its complexes of various compositions with amines and sulfides in dichloroethane and benzene are compared. The special features of the structure and behavior of comple xes with secondary amines are analyzed. Medium effects on the IR spectrum o f the Pd(OAc)(2). 2Pr(2)S complex in benzene, dichloroethane, and acetonitr ile solutions are discussed. It is shown that, as in crystals, palladium di acetate forms trimers in solutions. In benzene solutions, the trimeric pall adium diacetate molecule is solvated; benzene also solvates palladium diace tate complexes with secondary amines because of the presence of Pd-O-C=O . . .H-N rings formed by intramolecular N-H . . .O=C H-bonds. An increase in permittivity in the benzene-dichloroethane-acetonitrile series of solvents causes an increase in the fraction of the polar cis isomer of the Pd(OAc)(2 ). 2Pr(2)S complex.