Synthesis of tris- and tetrakis(pyrazol-1-yl)borate gold(III) complexes.: Crystal structures of [Au{κ2-N,N′-BH(Pz)3}Cl2] (pz = pyrazol-1-yl) and [Au{κ2-N,N′-B(Pz)4} (κ2-C,N-C6H4CH2NMe2-2)]ClO4•CHCl3

Na[BH(pz)(3)] and Na[AuCl4].2H(2)O react in water (1:1) to give [Au{k(2)-N,N'-BH(pz)(3)}Cl-2] (1) or, in the presence of NaClO4 (2:1:1), the cationic complex [Au{k(2)-N,N'-BH(pz)(3)}(2)]ClO4 (2). The reactions of Na[B(pz)(4)] with the cyclometalated gold complexes [AuRCl2] and NaClO4 (1:1:1) produce [Au{(2)-N,N'-B(pz)(4)}(R)]ClO4 [R = k(2)-C,N-C6H4CH2NMe2-2 (3)] or [Au{k(2)-N,N'-B(pz)(4)}(R)Cl] [R = C6H3(N=NC6H4Me-4')-2-Me-5 (4)], respectively, although 4 is better obtained in the absence of NaClO4, The crystal structures of 1 and 3.CHCl3 are reported. Both complexes display the gold center in square planar environments, two coordination sites being occupied by the chelating poly(pyrazolyl)borate ligands.