STUDIES OF PHOSPHAZENES .34. GROUP-6 METAL-CARBONYL-COMPLEXES OF BIS(PYRAZOLYL)CYCLOTRIPHOSPHAZENES

Reactions of the bis(3,5-dimethylpyrazol-1-yl)cyclotriphosphazenes gem -N3P3Ph4(C3HN2Me2)2 (L1) and N3P3(MeNCH2CH2O)2(C3HN2Me2)2 (L2) with [M (CO)6] (M = Mo or W) afford complexes of the type [M(CO)3L] (L = L1 or L2), which have been characterised by IR and NMR spectroscopic data. The structures of [Mo(CO)3L1], [W(CO)3L2] and the ligand L2 have been determined by single-crystal X-ray diffraction. The phosphazenes act a s novel tridentate NNN-donor ligands with two pyrazolyl nitrogen atoms and one phosphazene ring nitrogen atom bonded to the metal atom.