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

Abstract

The silver(I) amidinates bis[μ-N 1,N 2-bis(propan-2-yl)benzamidinato-κ2 N 1:N 2]disilver(I), [Ag2(C13H19N2)2] or [Ag{PhC(NiPr)2}]2 (1), and bis(μ-N 1,N 2-dicyclohexyl-3-cyclopropylpropynamidinato-κ2 N 1:N 2)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-N 1,N 2-dicyclohexyl-3-cyclopropylpropynamidinato-κ2 N 1:N 2)disilver(I) bis(μ-N 1,N 2-dicyclohexyl-3-cyclopropylpropynamidinato-κ3 N 1,N 2:N 1)bis(tetrahydrofuran-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 tetrahedral 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.