Three-Coordinate Nickel(II) and Nickel(I) Thiolate Complexes Based on the β-Diketiminate Ligand System

摘要

Mononuclear nickel(II) thiolate complexes [L~(tBu_Ni(SEt)] (1) and [L~(tBu)Ni(aet)] (2, aet = ~-S(CH_2)_2NH_2) (L~(tBu) = [HC(C(~tBu)- NC_6H_3(iPr)_2)_2]~-), supported by a bulky nacnac ligand, were synthesized by treatment of the nickel(II) bromide precursor [L~(tBu_Ni(Br)] (I) with the potassium salts of ethanethiol and cysteamine, respectively. The nickel atom in 1 features a planar T-shaped environment, while the Ni ion within 2 shows a distorted square planar coordination geometry, as the aminoethanethiolate (aet) is coordinated as a chelating ligand. In 2 the β-diketiminate ligand binds in a rarely observed κ~2C,N coordination mode. Reduction of complex 1 or its benzenethiolate analogue [L~(tBu_Ni(SPh)] (II) by KC_8 resulted in the formation of dinuclear NiI thiolates (K?OEt_2)(K)[L~(tBu_Ni(SEt)]_2 (3) and (K?OEt_2)_2[L~(tBu_Ni(SPh)]_2 (4), respectively. In these compounds [LtBuNi- (SR)]~- units are held together by potassium cations produced in the reduction process. All compounds mentioned were structurally characterized by singlecrystal X-ray crystallography.