Synthesis, characterization, and solution properties of skeletally stabilized triphosphazanes

The new skeletally stabilized dichlorotriphosphazanes C6H4N2(PhPCl)(2)PPh (5) and C6H4N2(MePCl)(2)PMe (6) have been prepared from reactions between PhPCl2 or MePCl2 and 1,2-(NH2)(2)C6H4 or 1,2-(Me3SiNNH)(2)C6H4, respectively. Reaction of PhPCl2 with the phosphadiazole C2H4(Me3SiN)(2)PPh yields triphosphazane C2H4N2(PhPCl)(2)PPh (8). Compounds 5, 6, and 8 form as mixtures of three diastereomers; characterization is based on spectral data and derivatization of 5 and 8 to the amino and thio(amino) triphosphazanes C6H4N2[PhP((NHPr)-Pr-i)](2)PPh (7) and C2H4N2[PhP(S)NEt2](2)PPh (10). The P-31 NMR spectra of 5 and 6 in solution have been measured as a function of temperature and solvent donor and dielectric strength. The solution properties of the dichlorotriphosphazanes and the implications of these on subsequent reaction chemistry are discussed.