Are formal oxidation states above one viable in cyclopentadienylcopper cyanides?
ABSTRACT Recent experiments have led to the discovery of the thermally unstable organocopper compounds (η(3)-C(3)H(5))CuMe(2), [(η(3)-C(3)H(5))CuMe(3)](-), and CuMe (4)(-) in which the copper atom is in the +3 formal oxidation state. In a quest for more stable organocopper compounds with copper in formal oxidation states above one, the binuclear cyclopentadienylcopper cyanides Cp(2)Cu(2)(CN)(n) (Cp = η(5)-C(5)H(5); n = 1, 2, 3) have been studied using density functional theory (DFT). The lowest energy structures are found to have terminal Cp rings and bridging cyanide ligands up to a maximum of two bridges. Higher-energy Cp(2)Cu(2)(CN)(n) (n = 1, 2, 3) structures are found with bridging Cp rings. The Cp(2)Cu(2)(CN)(3) derivatives, with the copper atoms in an average +2.5 oxidation state, are clearly thermodynamically disfavored with respect to cyanogen loss. However, Cp(2)Cu(2)(CN)(2) and Cp(2)Cu(2)(CN), with the copper atoms in the average oxidation states +1.5 and +2, respectively, are predicted to have marginal viability. The prospects for the copper(II) derivative Cp(2)Cu(2)(CN)(2) contrast with that of the "simple" Cu(CN)(2), which is shown both experimentally and theoretically to be unstable with respect to cyanogen loss to give CuCN.
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ABSTRACT: In this review we highlight recent progress in DFT/TDDFT application to copper coordination compounds. Selected most recent applications that best illustrate the promise of DFT in the following active areas of copper coordination chemistry: (i) mechanistic studies of copper-catalyzed reactions, (ii) investigating the nature of bonding in copper coordination compounds, (iii) the bioactivity and biochemistry of copper coordination compounds and (iv) the photophysics (absorption and emission spectra) of copper coordination compounds are reviewed. This review is intended to be of interest to both experimentalists and theorists in the expanded field of copper coordination chemistry.RSC Advances 07/2014; 4(61). DOI:10.1039/C4RA04921G · 3.71 Impact Factor