Metallic carbonyl complexes containing heterocycles nitrogen ligands Part VI. Re(I), Mn(I), Mo(0), and W(0) compounds with 4 '-phenyl-2,2 ': 6 ',2 ''-terpyridine

The synthesis and spectroscopic characterization of new transition metal co mplexes containing the heterocyclic nitrogen ligand 4'-phenyl-2,2':6',2''-t erpyridine are reported. Complexes of the [XM(CO)(3)(L)] type (M = Re(I), M n(I), Mo(0), or W(0); X = Br or CO; and L = 4'-phenyl-2,2':6',2''-terpyridi ne) were prepared by photosubstitution or by thermolytic reactions. Aspects of the IR, UV-Vis, proton NMR spectra and electrochemistry of the complexe s are discussed. Special attention is given to the fact that the heterocycl ic nitrogen ligand ph-tpy acts as a bidentate or terdentate chelate in comp lexes of this type and shows the fluxionality in the coordination. Correlat ions between redox potentials and spectroscopic measurements indicate the v arious interactions of the ligand and the metal center, and allow the evalu ation of the metal-ligand back-donation. (C) 2001 Elsevier Science B.V. All rights reserved.