C. Topf, C. Hirtenlehner, M. Fleck
Dec 1, 2011
Zeitschrift für anorganische und allgemeine Chemie
3-Methyl-1-(2-picolyl)-imidazolium chloride (1) has been synthesized and used as a precursor for the preparation of the (NHC)AgCl complex [NHC = 3-methyl-1-(2-picolyl)imidazol-2-ylidene] (2). Transmetalation of 2 with (tht)AuBr (tht = tetrahydrothiophene) yields the corresponding (NHC)AuBr complex 3, which is further oxidized by Br2 to give the (NHC)AuBr3 compound 4. Treatment of 4 with one equivalent of solid AgBF4 affords the [(NHC)AuBr2][BF4] congener 5 as a pale green, crystalline powder. The structure of 4 and 5 were determined by single-crystal X-ray diffraction, revealing for 5 a κ-N-coordination of the AuIII atom by the picolyl nitrogen atom. Further attempts to exchange all bromides by carboxylates results in the reduction to the dimeric AuI compound [(NHC)2Au2][BF4]2, 6.