TEATRAARYL METHANE ANALOGS IN GROUP-14 .3 . AR4SN PB (AR = PH, PARA-TOL, META-TOL, ORTHO-TOL, 2,4-XYL AND 2,5-XYL) - COMPARISON OF BOND LENGTHS AND ANGLES, OF NMR CHEMICAL-SHIFTS AND COUPLING-CONSTANTS AND OF VIBRATION DATA/

The title compounds have been synthesized by Grignard reactions or pyr olysis of diplumbanes respectively. The crystal structures of m-Tol4Pb and Ph4Pb (redetermination) have been determined. All eight compounds (Ph/Tol)4(Sn/Pb) are S4 symmetric and contracted along this unique ax is. The C-13-NMR chemical shifts and the couplings 1J(Sn-119/Pb-207-C- 13) as well depend additively upon the methyl substituents. The ratios 1K(Pb-207-C-13):1K(Sn-119-C-13) of the reduced coupling constants are all near to 1.61; a comparison with values from the literature for al kyl, alkenyl and alkinyl substituents is given. The ratio delta(Pb-207 ):delta(Sn-119) results in 2.28. IR (700 down to 200 cm-1) and Raman ( 700 down to 50 cm-1) data are given.