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]

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.