Crystal and mol-ecular structures of two silver(I) amidinates, including an unexpected co-crystal with a lithium amidinate.

The silver(I) amidinates bis-[μ-N(1),N(2)-bis-(propan-2-yl)benzamidinato-κ(2)N(1):N(2)]disilver(I), [Ag(2)(C(13)H(19)N(2))(2)] or [Ag{PhC(N (i) Pr)(2)}](2) (1), and bis-(μ-N(1),N(2)-di-cyclohexyl-3-cyclo-propyl-propynamidinato-κ(2)N(1):N(2))disilver(I), [Ag(2)(C(18)H(27)N(2))(2)] or [Ag{cyclo-C(3)H(5)-C≡C-C(NCy)(2)}](2) (2a), exist as centrosymmetric dimers with a planar Ag(2)N(4)C(2) ring and a common linear coordination of the metal atoms in the crystalline state. Moiety 2a forms a co-crystal with the related lithium amidinate, namely bis-(μ-N(1),N(2)-di-cyclo-hexyl-3-cyclo-propyl-propynamidinato-κ(2)N(1):N(2))disilver(I) bis-(μ-N(1),N(2)-di-cyclo-hexyl-3-cyclo-propyl-propynamidinato-κ(3)N(1),N(2):N(1))bis-(tetra-hydro-furan-κO)lithium(I) toluene monosolvate, [Ag(2)(C(18)H(27)N(2))(2)][Li(2)(C(18)H(27)N(2))(2)(C(4)H(8)O)(2)]·C(7)H(8) or [Ag{cyclo-C(3)H(5)-C≡C-C(NCy)(2)}](2)[Li{cyclo-C(3)H(5)-C≡C-C(NCy)(2)}(THF)](2)·C(7)H(8), composed as 2a × 2b × toluene. The lithium moiety 2b features a typical ladder-type dimeric structure with a distorted tetra-hedral coordination of the metal atoms. In the silver(I) derivatives 1 and 2a, the amidinate ligand adopts a μ-κN:κN' coordination, while it is a μ-κN:κN:κN'-coordination in the case of lithium derivative 2b.