CHEMISTRY OF POLYFUNCTIONAL MOLECULES .118. SYNTHESES AND CRYSTAL-STRUCTURES OF BICYCLIC METALLAPHOSPHAZENES WITH 4-MEMBERED AND 6-MEMBERED RINGS

Anhydrous MCl(2) (M = Pt, Fe) react with LiN(PPh(2))(2) (1) in the molar ratio of 1:2 in boiling toluene within 25 hours under partially oxidative scrambling of the PNP chain in 1 yielding the bicyclic metallaphosphazenes 5a,b. While compound 5a can be isolated in substance, the intermediate 5b proves to be highly reactive but can be stabilized in the presence of CO, forming the 18-valence-electron coordination compound [Fe2+(CO)(2)(Ph(2)P<($)triple over dot-N<($)triple over dot-PPh(2)(-))(Ph(2)P-N = PPh(2) = N-Ph(2)(-))] (6) as an isomeric trans(6a)/cis(6b) mixture in the molar ratio of 99:1. Also treatment of anhydrous PtCl4 with four equivalents of 1 in boiling toluene during 60 hours yields 5a. Alkylation of 5a with CH,I leads to the formation of the ionic species [Pt(2+)Ph(2)p-N(CH3)-pph(3))(Ph(2)P-N = PPh(2) = N-PPh(2)(-))]I-(9). The X-ray crystal structures of 5ax1 CH2Cl2 and 6a reveal, that the metal centres have a planar P-coordination polyhedron in the the solid state. In the complex 9x2,5 CH2Cl2 however the torsion angle between the P-Pt-P planes of the four and six membered rings shows to be 15 degrees. The six membered metallacycles in 5ax1 CH2Cl2, 6a and 9x2,5 CH2Cl2 differ in their geometrical arrangement. All the new compounds have also been characterized by their H-1, P-31{H-1}, C-13{H} NMR, IR, Raman and mass spectra.