Synthesis and structural study of quinoline(μ1,μ3)-thiocyanate silver(I) complex

Departemen Kimia, FMIPA, Universitas Negeri Malang, Jalan Semarang 5, Malang, Indonesia 65145

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Abstract

A new quinoline(μ1,μ3)-thiocyanatesilver(I) complex, [Ag(Q)(SCN)]ₙ, (Q = quinoline, C₉H₇N) has been successfully synthesized through a direct reaction at room temperature between silver(I) nitrate, quinoline ligand, and potassium thiocyanate in a 1:1:1 molar ratio. Colorless crystals were obtained after nine days of evaporation. FT-IR analysis confirmed the presence of characteristic functional groups from both quinoline and SCN⁻ ligands. Refinement results from SC-XRD indicated that the silver(I) complex crystallizes in a pseudo-tetrahedral structure with an orthorhombic crystal system and space group P 212121(a = 4.0877(2) Å, b = 13.4948(8) Å, c = 18.0710(11) Å; α = β = γ = 90°). The R-factor value of 6.78% demonstrates that the refined structure is in close agreement with the actual molecular arrangement. Hirshfeld surface analysis further revealed intermolecular interactions with distances shorter than 8 Å, in which the dominant contact is H···H, contributing 29.2% of the total interactions. Antibacterial testing against Staphylococcus aureus and Escherichia coli revealed moderate activity, higher than the free ligands but lower than AgNO₃ and chloramphenicol, indicating that Ag(I) coordination enhances antibacterial performance.