An equimolar reaction mixture of Ph2PCl and GaCl3 at room temperature results in the formation of a melt. The melt provides a facile and reactive source of the Ph2P+ cation, as demonstrated by P–P bond insertion into (PhP)5 to give the [Ph4P6]2+ dication and reductive coupling with gallium metal to give the diadduct Cl3GaPPh2PPh2GaCl3.

An equimolar reaction mixture of Ph2PCl and GaCl3 at room temperature results in the formation of a melt M consisting of the donor–acceptor complex Ph2PCl→GaCl3 (1a), the chloro(diphenylphosphanyl)diphenylphosphonium cation (2a), and the counteranions [GanCl3n+1]– (n = 1, 2, 3). The melt has been characterized by Raman and NMR spectroscopy and is compared with the reaction mixture of Ph2PCl and GaCl3 observed in solution (CH2Cl2). The melt provides a facile and reactive source of the diphenylphosphenium cation, as demonstrated with use for P–P bond insertion into (PhP)5, to give the 2,3,4,5-tetraphosphanyl-1,4-diphosphonium dication (3), and reductive coupling with gallium metal to give the diadduct Cl3GaPPh2PPh2GaCl3 (5).(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)