Mono- and Dinuclear Complexes of Tricarbonylrhenium(I) with 4-Methyl-2,2′-bipyridine-4′-carbonitrile

J.H. MECCHIA ORTIZ; F.E. MORÁN VIEYRA; C. D. BORSARELLI; I. ROMERO; X. FRONTRODONA; T. PARELLA; N.D. L. DE KATZ; F. FAGALDE; N. KATZ

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY

WILEY-V C H VERLAG GMBH

Año: 2014 vol. 21 p. 3359 - 3369

1434-1948

Novel mono- and dinuclear tricarbonylrhenium(I) complexes of formula [Re(Mebpy-CN)(CO)3Cl] (1), [Re(Mebpy-CN)-(CO)3(CH3CN)](PF6) (2), and [(CH3CN)(CO)3Re(Mebpy-CN)Ru(NH3)5](PF6)3 (3), in which Mebpy-CN = 4-methyl-2,2-bipyridine-4-carbonitrile, were prepared and characterized by spectroscopic, photophysical, and computational techniques. The complete structure of complex 2 was determined by Xray diffraction. The increased conjugation in the bipyridyl ring owing to the nitrile substituent increases the emission quantum yields of the 3MLCT (metal-to-ligand charge-trans-fer) lowest-lying excited states of 1 and 2 with respect to the corresponding bpy complexes (bpy = 2,2-bipyridine). The mixed-valent species of formula [(CH3CN)(CO)3Re(Mebpy-CN)Ru(NH3)5]4+ (4) was prepared in situ and as a mixed salt; the charge recombination from its metal-to-metal chargetransfer (MMCT) excited state is predicted to lie in the Marcus inverted region. The electronic structures and optical properties of all the reported complexes calculated by DFT and TD-DFT methods agree reasonably well with experimental results.3Cl] (1), [Re(Mebpy-CN)-(CO)3(CH3CN)](PF6) (2), and [(CH3CN)(CO)3Re(Mebpy-CN)Ru(NH3)5](PF6)3 (3), in which Mebpy-CN = 4-methyl-2,2-bipyridine-4-carbonitrile, were prepared and characterized by spectroscopic, photophysical, and computational techniques. The complete structure of complex 2 was determined by Xray diffraction. The increased conjugation in the bipyridyl ring owing to the nitrile substituent increases the emission quantum yields of the 3MLCT (metal-to-ligand charge-trans-fer) lowest-lying excited states of 1 and 2 with respect to the corresponding bpy complexes (bpy = 2,2-bipyridine). The mixed-valent species of formula [(CH3CN)(CO)3Re(Mebpy-CN)Ru(NH3)5]4+ (4) was prepared in situ and as a mixed salt; the charge recombination from its metal-to-metal chargetransfer (MMCT) excited state is predicted to lie in the Marcus inverted region. The electronic structures and optical properties of all the reported complexes calculated by DFT and TD-DFT methods agree reasonably well with experimental results.