PREPARATION AND SPECTROSCOPIC STUDIES OF SOME CYCLIC UREA ADDUCTS OF TRIPHENYL-THIN AND -LEAD HALIDES

Article abstract of DOI:10.1016/0022-328X(85)80267-9

1,3-Dimethyl-2-imidazolidinone (dimethylethylene urea, DMEU) and 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone (dimethylpropylene urea, DMPU) adducts of the type Ph3SnX*L (X = Cl, Br and I), Ph3PbX*L (X = Br, I), 3Ph3PbCl*2DMEU and 2Ph3PbCl*DMPU have been prepared and characterized.Assignments are made for ν(CO) and ν(CN) frequencies in the IR, and for skeletal frequencies observed in both IR and Raman spectra in the range 400 to 100 cm^-1.Infrared measurements show that the adducts are bound through the carbonyl oxygen, and are highly dissociated in dichloromethane solution. 1H and 119 Sn or 207Pb NMR measurements reveal that ligand exchange, fast on the NMR time scale, occurs in solution.Coordination of the ligand causes a large upfield shift in the 119Sn or 207Pb resonances, but Ph3MI*L have shifts similar to those for the parent iodides, indicating almost complete dissociation.Thermodynamic parameters are reported for the dissociation of Ph3SnX*DMPU (X = Cl, Br) in Ch2Cl2 solution