CHEMISTRY OF POLYFUNCTIONAL MOLECULES - 129 - SYNTHESIS AND X-RAY STRUCTURES OF NOVEL LEAD(1- DETAILED PB-207 NMR-SPECTRA OF THE PB-207-LABELED DIMERIC LEAD(1+) SPECIES() AND INDIUM(3+) PHOSPHAZENIDE COMPLEXES)

The reaction of PbCl2 with LiN(PPh2)(2) (1) at -78 degrees C affords t he P-P coupled phosphazene Ph2P-N=PPh2-PPh2=N-PPh2 (2) as an oxidation product and, as a reduction equivalent, the novel lead(1+) complex [( Pb1+)(2)(mu-Ph2P - N - PPh2-)(2)](Pb-Pb) (3). The crystal structure de termination of the red compound 3 shows a Pb-Pb bond length of 304.1(1 ) pm. The P-31- and Pb-207-NMR spectra of 3 are complicated due to the presence of a higher order spin system (AA'A '' A'''X for the mono-Pb -207 isotopomer, AA'A '' A'''XX' for the bis-Pb-207 isotopomer). Simul ations of the P-31 and Pb-207 spectra both on material with natural is otope abundance and on the Pb-207-labelled compound (3) reveal a larg e Pb,Pb coupling constant of 7708 Hz, indicative of a covalent Pb-Pb b ond. - Though InCl3 is diagonally related to PbCl2, no significant red ox process is observed in the reaction between InCl3 and 1. The yellow crystals of [In3+(Ph2P - N - PPh2-)(3)] (4) that are obtained were al so investigated by X-ray analysis. These show a propeller-like configu ration of the three four-membered chelate rings with indium(3+) as the centre.