Synthesis and Structural and Physicochemical Characterization of {[Rh2(μ-OOCCH3)2(dmbpy)2][BF4]}n Molecular Wire

Dinuclear Rh-II compounds [Rh-2(mu-OOCCH3)(2)(dmbpy)(2)-(H2O)(2)](CH3COO)(2) (1) and [Rh-2(mu-OOCCH3)(2)(dmbpy)(2)(H2O)(2)](BF4)(2)center dot 2.5H(2)O (2) (dmbpy = 4,4'-dimethyl-2,2'-bipyridine) were synthesized and characterized with spectroscopic methods. The structure of complex 2 was determined by using X-ray crystallography. The rhodium atoms in compound 2 have distorted octahedral coordination with O and N atoms in equatorial positions and a Rh atom and a H2O Molecule in axial coordination sites. Reduction of compound 2 with aqueous alcohols leads to the formation of the molecular wire {[Rh-2(mu-OOCCH3)(2)(dmbpy)(2)][BF4]}(n)center dot 2nH(2)O (3) containing a [Rh-2](3+) core. Compound 3 shows strong antiferromagnetic properties, J = -780 cm(-1) and p = 0.128-1.349 B.M. in the range 1.8-300 K. The electrochemistry of compound 2 in acetonitrile was investigated. Complex 2 is irreversibly oxidized to a Rh-III compound at E-pa = 1.5 V and reduced to a wire with a [Rh-4](6+)core at E-1/2 = -0.87 V showing the same properties as those of the product obtained during chemical reduction. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)