Synthesis of Intermediates in the C-H Activation of Acetone with 2-PhenylazophenylgoId(III) Complexes and in the C-C Coupling of Aryl Groups from Diarylgold(III) Complexes. Crystal and Molecular Structures of [Au{c,H,(N=NC,H4Me-4')-2-Me-5}(acac-C)CI] (acac = acetylacetonate), ciS-[Au(C,H4N=NPh-2)CI2( PPh,)], and [AU(C6H,CH2hiMe2-2)(c6F5)CI]

Abstract

The complex [Au(C,H4N=hJPh-2)CI2] reacts with [HgR,] (R = C,H4N02-2 or c$,) and NMe4CI ( 2 1 :2) to give [Au(C6H4N=f'hPh-2)(R)CI] [R = C,H4N0,-2, (1); or c,F, (2)]. Similarly, [-N)CI,] (3) [C-N = C6H,( N=NC6H4Me-4')-2-Me-5], prepared by the reaction of [AuCl,(tht)] (tht = tetrahydrothiophene) with [Hg(C-N)CI] and NMe,CI (1 : 1 : l), reacts with Tl(acac) (Hacac =acetylacetone) (1 :1) to give [ w N ) ( a c a c - C ) C l ] (4). Reaction of (2) with PPh, (1 :1) leads to [Au(C,H4N=6JPh-2) (C,F,)CI(PPh,)] (5), which upon standing in dichloromethane solution decomposes to give a mixture of [AU(C,F,) (PPh,)], C,H,C,F,-l -N=NPh-2, and [Au(C,H4N=NPh-2)CI,( PPh,)] (6). Crystal structures were determined for complexes (4), (6), and [Au(C,H4CH2dlMe,-2)(C,F,)CI] (7) [(4), space group Pi, a = 9.475(4), b = 9.923(4), c = 10.91 3(4) A, a = 63.75(3), f3 = 84.92(3), y = 89.41 (3)", Z = 2, R = 0.020 for 3 057 reflections at -95 "C; (6), space group P2,/n, a = 10.361 (3), b = 28.1 94(8), c = 10.724(4) A, p = 11 6.26(2)", Z = 4, R = 0.038 for 3 734 reflections at 20 "C; (7), space group Pbca, a = 11.996(4), b = 14.484(4), c = 18.31 O(7) A, Z = 8, R = 0.045 for 1 909 reflections at 20 "C]. The three structures reveal neutral molecules with square-planar geometry around the gold atom. In complexes (4) and (7) the aryl groups act as chelating ligands, forming a five-membered ring [(4), Au-C 2.026(4), Au-N 2.1 58(3) A; (7), Au-C 2.022(10), Au-N 2.1 28(1 O), Au-C,F, 2.01 2(11) A] while in complex (6) the aryl group acts as a monodentate ligand [Au-C 2.033(5) A]. The chloro ligand in complex (4) is trans to the carbon atom of the aryl ligand [Au-CI 2.349(2) A], and the acac ligand is C-bonded to the gold atom [Au-C 2.083(4) A]. This is one of the few isolated acetylacetonatogold(iri) complexes and the first structurally characterized. In complex (6), chloro atoms are mutually cis [Au-CI (trans to C) 2.377(2), (trans to N) 2.325(2) A]. The chloro ligand in complex (7) is trans to the aryl group of the chelating ligand [Au-CI 2.347(3) 4. The isolation of complexes (1) and (2) and the observed geometry of (4) support the pathway suggested for the C-H activation of acetone with 2-phenylazophenylgold( 111) complexes.