The conjugative bridging of organometallic reaction centers in heterodinuclear complexes (OC)3ClRe(m-L)MCl(C5Me5)+, M = Rh or Ir - Spectroscopic consequences of reductive activation

, , , and . Zeitschrift fuer Anorganische und Allgemeine Chemie, 630 (12): 1883--1893 (2004)
DOI: 10.1002/zaac.200400174


Heterobimetallic rhenium-rhodium and rhenium-iridium organometallic complexes bridged by conjugated bis-chelate nitrogen heterocyclic ligands, were prepd.; their electroredn. gives corresponding radical-anions, which were studied by ESR and IR spectroscopy. Complexes (I-III) as PF6- salts; M = (h5-C5Me5)RhCl, (h5-C5Me5)IrCl were prepd. by complexation of corresponding rhenium complexes Re(CO)3Cl(bpip), Re(CO)3Cl(bptz) and Re(CO)3Cl(bpym) (bpip, bptz, bpym are for 2,5-bis(1-phenyliminoethyl)pyrazine, 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine and 2,2'-bipyrimidine, resp.) with (h5-C5Me5)MCl2. The stepwise reductive activation accompanied by chloride dissocn. was studied by cyclic voltammetry and spectroelectrochem. in the range of CO stretching vibrations (IR), charge transfer absorptions (UV/Vis) and ESR for paramagnetic intermediates of the mono- and heterobinuclear compds. While complexes of bpip and bptz form one-electron reduced radical intermediates (OC)3ClRe(m-L)MCl(C5Me5).bul., the compds. with bpym follow MCl-dissociative two-electron redn. pathway, giving (OC)3ClRe(m-L)M(C5Me5). on SciFinder(R)

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