Synthesis and structure of copper(I), silver(I) and zinc(II) amides [Cu2(mpsa)2], [Cu6X2(mpsa)4](X = Cl or Br), [Ag4(mpsa)4] and [(ZnEt)2(mpsa)2][mpsa = 2-N(SiMe3)C5H3N-6-Me]

Abstract

The copper(I) amide [Cu₂(mpsa)₂]1 and its 1 : 1 adduct with CuX, [Cu₆(mpsa)₄X₂](X = Cl, 2a or Br, 2b){mpsa =[2-(6-methyl)pyridyl]trimethylsilylamido, 2-N(SiMe₃)C₅H₃N-6-Me}, the silver(I) amide [Ag₄(mpsa)₄]3 and the zinc(II) amides [(ZnEt)₂(mpsa)₂]4, [ZnCl(mpsa)]5, and [Zn(mpsa)₂]6, have been prepared from lithium reagents and the appropriate metal halide, and Hmpsa and ZnEt₂(4 and 6). The amides 1–4 have been characterized crystallographically. In 1 the ligands span the two metal centres with Cu–N_amido 1.875(4), 1.887(4), Å, Cu–N_pyridyl 1.902(4), 1.903(4)Å, N–Cu–N 174.6(2), 173.4(2)°, and Cu ⋯ Cu 2.420(1)Å. Complexes 2a and 2b are isomorphous diethyl etherates; mpsa ligands span three metal centres with each N_amido bridging (i) a two-co-ordinate copper, the other co-ordination site being another N_amido, Cu–N 1.893(6)–1.927(7)Å, 2a, 1.884(9)–1.919(8)Å, 2b, and (ii) a three-co-ordinate copper bound by the amido centre, Cu–N, 2.100(6)–2.133(6)Å, 2a, 2.100(8)–2.152(9)Å, 2b, a pyridyl N-centre, 1.993(7)–2.006(7)Å, 2a, 1.983(9)–2.013(8)Å, 2b, and a halide, Cu–X 2.270(3)–2.303(3)Å, 2a, 2.409(3)–2.410(2)Å, 2b. Complex 3 is a hexane solvate; mpsa ligands link four silver atoms in plane; two silver atoms lie on a C₂ axis and are two-co-ordinate, bound by pairs of N_pyridyl groups; Ag–N, 2.140(3), 2.169(6)Å with N–Ag–N, 169.3(2), 171.2(2)°; the other (symmetry-related) pair are two-co-ordinate, bound by pairs of N_amido groups: Ag–N, 2.099(3), 2.097(4), with N–Ag–N, 168.6(2)°. In complex 4 the N_amido groups bridge the metal centres with N_pyridyl forming chelate rings on the same side of a Zn₂N₂ plane; Zn–N_pyridyl 2.125(5), 2.108(5)Å, Zn–N_amido 2.061(5), 2.072(5)Å(chelate ring), 2.245(5), 2.225(5)Å, Zn ⋯ Zn 2.958(2)Å. Compound 1 forms an adduct with trimethylphosphine, [Cu(mpsa)(PMe₃)₂]7.