Heteroleptic Silver(I) Complexes of Dithiocarbamate and Phosphine Ligands: Synthesis, Characterization, and Their Application in Multicomponent Organic Reactions

Silver(I) complexes incorporating soft donor ligands such as dithiocarbamates and phosphines have attracted considerable attention owing to their diverse structural features and notable catalytic activities. In this study, a series of heteroleptic Ag(I) complexes with the general formula [Ag(I)(PPh3)2(L1-L3)] (C1–C3) were quantitatively synthesized using designed dithiocarbamate ligand salts (KL1–KL3), where L1 = N,N-dibenzyl dithiocarbamate, L2 = N-ferrocenylmethyl-N-benzyl dithiocarbamate, L3 = N-ferrocenylmethyl-N-3-methylpyridyl dithiocarbamate, in combination with triphenylphosphine as a coligand. All heteroleptic Ag(I) complexes were characterized by Fourier transform infrared (FT–IR), ultraviolet–visible (UV–vis), multinuclear NMR, high-resolution mass spectra (HRMS), and elemental analyses. The solid-state structures of complexes C1 and C3 are confirmed by single-crystal X-ray diffraction (SCXRD). The X-ray structures revealed a distorted tetrahedral AgP2S2 coordination environment with a bidentate dithiocarbamate ligand and two PPh3 ligands. The catalytic potentials of C1–C3 were subsequently investigated in one-pot multicomponent organic transformations, enabling the efficient synthesis of benzopyranopyrimidine and propargylamine derivatives, which are valuable heterocyclic and biologically relevant organic molecules. The optimized conditions afforded the corresponding products in good to excellent yields, demonstrating the ability of the Ag(I) heteroleptic complexes of dithiocarbamate and phosphine ligands to promote multicomponent C–C/C–N bond-forming processes efficiently under mild reaction conditions.