Copper(I) bis(mercaptoimidazolyl)methane complexes

INOR 611

Tiffany A. Pinder, tapinder@uncc.edu1, Leigh A. Graham, lagraham@uncc.edu1, Kevin A. Kreisel2, Glenn P. A. Yap2, and Daniel Rabinovich, drabinov@email.uncc.edu1. (1) Department of Chemistry, The University of North Carolina at Charlotte, 9201 University City Boulevard, Charlotte, NC 28223, (2) Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716
The bis(mercaptoimidazolyl)methanes (BmmR) are sulfur-donor ligands that can be regarded as neutral analogues of the anionic bis(mercaptoimidazolyl)borates [BmR]-. The methyl-substituted derivative BmmMe, introduced more than 15 years ago (D. J. Williams, 1989), remains the only known member of this family of ligands and its coordination chemistry is limited to a few main group (Pb, Sb, Bi) and transition metal (Re, Rh, Ag) complexes. We describe in this presentation the synthesis and characterization of the first complexes of copper(I) with the BmmMe ligand, including (BmmMe)CuX and (BmmMe)Cu(PPh3)X (X = Cl, Br, I) derivatives. The (BmmMe)CuX compounds cleanly react with bis(pyrazolyl)borates (BpRR') (R = R' = H or Me) to produce the mixed-donor complexes (BmmMe)Cu(BpRR'). These neutral complexes contain unusual [CuS2N2] cores where both sulfur donor groups are heterocyclic thiones and, as such, are excellent structural models for the copper-binding site in methanobactin, a recently-reported protein present in methane-oxidizing bacteria such as pMMO. In addition, we disclose the preparation of the new tert-butyl-substituted analogue BmmtBu and our initial survey of its coordination chemistry towards copper(I) and the group 12 metals.