SPIN ADDUCTS BETWEEN THIOKETONES AND PHOSPHORUS CENTERED RADICALS .2. AN ELECTRON-SPIN RESONANCE STUDY OF THE ADDITION OF PHOSPHINYL, PHOSPHONYL AND THIOPHOSPHONYL RADICALS TO DIARYL AND DIALKYL THIOKETONES

The paramagnetic adducts between a variety of phosphinyl, phosphonyl or thiophosphonyl radicals and thiobenzophenone, 9,H-xanthen-9-thione, 9, H-thiaxanthen-9-thione, 9, H-selenaxanthen-9-thione and di-tert-butyl thioketone have been generated and studied by means of ESR spectroscopy. Attention has been focused on the variations ofFull-size image (<1 K)(31P) with the nature of the ligands L in the attacking PLn radicals and with the nature of the thiocarbonylic substrates. In all cases the reactions with the precursors of phosphinyl radicals afforded, beside the expected adducts, additional paramagnetic species, identified as the corresponding phosphonyl and thiophosphonyl adducts: while the formation of the former reflects the high sensitivity of tervalent phosphorus compounds to oxidizing agents, the latter adducts are believed to originate from desulfuration of the thioketones by the starting phosphines.