Preparation, spectroscopic properties, and dynamic behavior of a μ-oxo dirhenium(III) complex [Re2(μ-O)Cl2(tpa)2](PF6)2 (tpa=tris(2-pyridylmethyl)amine)
2002; Elsevier BV; Volume: 337; Linguagem: Inglês
10.1016/s0020-1693(02)01035-6
ISSN1873-3255
AutoresHideki Sugimoto, Takuya Takahira, Takashi Yoshimura, Motoo Shiro, Mikio Yamasaki, Hiroyuki Miyake, Keisuke Umakoshi, Yōichi Sasaki,
Tópico(s)Molecular Junctions and Nanostructures
ResumoAn oxo-bridged dirhenium(III,III) complex of tris(2-pyridylmethyl)amine (tpa) and its one-electron oxidized (III,IV) species, [Re2(μ-O)Cl2(tpa)2]3+,4+ have been prepared. They are new members to a series of rhenium tpa complexes in various oxidation states. X-ray structural determination of the Re2(III,IV) complex revealed practically linear ReORe bridge (178(1)°) with short ReO distances of 1.85(2) Å indicative of some multiple bonded character. The 1H NMR spectrum disclosed the relatively slow rotation around the ReORe axis in CH3CN solution in the timescale of 1H NMR. The complex undergoes two consecutive reversible one electron oxidations Re2(III,III)/(III,IV) and Re2(III,IV)/(IV,IV) at E1/2=0.23 and 0.90 V vs Ag/AgCl, respectively. Strong visible absorption bands are observed for the Re2(III,III) species at 448 (ε=31 160) and 563 nm (19 550) which are tentatively assigned to MLCT transitions. A unique oxidation product, Re2(μ-O)(O)2Cl2(bpaO2)2 (bpaO2H=1,3-bis(2-pyridyl)-2-aza-propanedione) has also been isolated and its crystal structure was determined. The complex is dirhenium(V) species with linear OReOReO moiety. Ligand tpa has been oxidized to ketone with simultaneous dissociation of one of the 2-pyridylmethyl arms.
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