Electrochemistry of mixed-metal bimetallic complexes containing the pentacyanoferrate(II) or pentaammineruthenium(II) metal center

Journal Article · Wed Mar 30 04:00:00 EST 1983 · Inorg. Chem.; (United States)

DOI:https://doi.org/10.1021/ic00149a021· OSTI ID:5446360

Moore, K J; Lee, L; Mabbott, G A; Petersen, J D

The electrochemistry of a series of mixed-metal bimetallic complexes of the type B/sub 5/MLM'B'/sub 5/, where B/sub 5/M = (CNN)/sub 5/Fe/sup II/ or (NH/sub 3/)/sub 5/Ru/sup II/, L = pyrazine, 4,4'-bipyridine, or 4-cyanopyridine, M'B'/sub 5/ = Rh/sup III/(NH/sub 3/)/sub 5/ or Co/sup III/(CN)/sub 5/, is reported. The bimetallic complexes all have metal-to-ligand charge-transfer (MLCT) bands associated with the M-B unit (d/sub ..pi../M ..-->.. p/sub ..pi../*L). The effect of the remote metal center, M'B'/sub 5/, is to function as a Lewis acid, shifting the MLCT maximum to lower energy and shifting the M/sup III///sup II/ reduction potential more positive with respect to free B/sub 5/ML. The remote metal influence is attenuated by longer bridging ligands and by reduced ..pi..-overlap. A comparison of the electrochemical data of the mixed-valence Fe(II)/Fe(III) and Ru(II)/Ru(III) complexes to the mixed-metal Fe(II)/Co(III) and Ru(II)/Rh(III) complexes has enabled a quantitative measure of the stabilization due to electron delocalization in the mixed-valence complexes. The results show that electron delocalization is greater for the ruthenium complexes than for the iron complexes, is a small contributor to the total stabilization of the mixed-valence state, and even in ruthenium drops off rapidly as the length of the bridge increases.

• Research Organization: Clemson Univ., SC
• DOE Contract Number: AS09-80ER10671
• OSTI ID: 5446360
• Journal Information: Inorg. Chem.; (United States), Journal Name: Inorg. Chem.; (United States) Vol. 22:7; ISSN INOCA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400400* -- Electrochemistry
CHEMISTRY
COBALT COMPLEXES
COMPARATIVE EVALUATIONS
COMPLEXES
ELECTROCHEMISTRY
IRON COMPLEXES
LIGANDS
RHODIUM COMPLEXES
RUTHENIUM COMPLEXES
STABILIZATION
TRANSITION ELEMENT COMPLEXES
VALENCE