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

The silver(I) amidinates bis-[μ-N1,N2-bis-(propan-2-yl)benzamidinato-κ2N1:N2]disilver(I), [Ag2(C13H19N2)2] or [Ag{PhC(N i Pr)2}]2 (1), and bis-(μ-N1,N2-di-cyclohexyl-3-cyclo-propyl-propynamidinato-κ2N1:N2)disilver(I), [Ag2(C18H27N2)2] or [Ag{cyclo-C3H5-C≡C-C(NCy)2}]2 (2a), exist as centrosymmetric dimers with a planar Ag2N4C2 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-N1,N2-di-cyclo-hexyl-3-cyclo-propyl-propynamidinato-κ2N1:N2)disilver(I) bis-(μ-N1,N2-di-cyclo-hexyl-3-cyclo-propyl-propynamidinato-κ3N1,N2:N1)bis-(tetra-hydro-furan-κO)lithium(I) toluene monosolvate, [Ag2(C18H27N2)2][Li2(C18H27N2)2(C4H8O)2]·C7H8 or [Ag{cyclo-C3H5-C≡C-C(NCy)2}]2[Li{cyclo-C3H5-C≡C-C(NCy)2}(THF)]2·C7H8, 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.