Abstract

The first spiro cyclic phosphazene containing a nitrile pendant coordinating group, N3P3(O2C12H8) 2(OC6H4CH2CN)2 (1), has been synthesized by the reaction of the spiro cyclophosphazene N3P3(O2C12H8) 2Cl2 with HOC6H4CH2CN and K2CO3 in acetone. The spiro nitrile derivative 1 reacted with CpFe(dppe)I and with CpRu(PPh3)2Cl in the presence of NH4PF6 in CH3OH as solvent to give the complexes {[CpFe(dppe)]2(NCCH2C6H4O) 2N3P3(O2C12H 8)2}(PF6)2 (2) and {[CpRu(PPh3)2]2(NCCH2C 6H4O)2N3P3(O 2C12H8)2}(PF6) 2 (3), respectively. The spectroscopic results indicate that the spiro nitrile derivative behaves like their nitrile ligands. These results have been confirmed by extended Hückel molecular orbital calculations which have been carried out on the model complexes [CpFe(PH3)2NCCH3]+ (4) and [CpFe(PH3)2(NC-CH2-C6H 4-O)(HO)5N3P3]+ (5). Two metal-to-ligand charge-transfer bands unprecedented in iron-nitrile complexes were observed in the electronic spectrum, as was predicted by the theoretical calculations. The electronic structures of complexes are discussed. © 1999 Elsevier Science S.A.