Inorganic Chemistry, Vol.46, No.7, 2836-2845, 2007
Synthesis, structure, and reactivity of mononuclear Re(I) oximato complexes
Complexes [Re(ONCMe2)(CO)(3)(bipy)] (1) and [Re(ONCMe2)(CO)(3)(phen)] (2), synthesized by reaction of the respective triflato precursors [Re(OTf)(CO)(3)(N-N)] (N-N = bipy, phen) with KONCMe2, feature O-bonded monodentate oximato ligands. Compound [Re(CO)(3)(phen)(HONCMe2)]BAr'(4) (3), with a monodentate N-bonded oxime ligand, was prepared by reaction of [Re(OTf)(CO)(3)(phen)], HONCMe2, and NaBAr'(4). Deprotonation of 3 afforded 2. The oximato complexes reacted with p-tolylisocyanate, p-tolylisothiocyanate, maleic anhydride, and tetracyanoethylene, affording the products of the insertion of the electrophile into the Re-O bond, compounds 4-7. One representative of each type of compound was fully characterized, including single-crystal X-ray diffraction. The reactions of 1 and 2 with dimethylacetylenedicarboxylate were found to involve first an insertion as the ones mentioned above but followed by incorporation of water, loss of acetone, and formation of the charge-separated neutral amido complexes 9 and 10. The structure of 9 and 10 was determined by X-ray diffraction, and key features of their electronic distribution were studied using a topological analysis of the electron density as obtained from the Fourier map.