Synthesis, Characterization and in Vitro Study of the Cytostatic and Antiviral Activity of New Polymeric Silver( I ) Complexes with Ribbon Structures Derived from the Conjugated Heterocyclic Thioamide 2‐Mercapto‐3,4,5,6‐tetra‐ hydropyrimidine

Silver( I ) bromide reacts with 2‐mercapto‐3,4,5,6‐tetrahydropyrimidine (StpmH 2 , C 4 H 8 N 2 S) in DMSO with an excess of triethylamine to give a water‐insoluble complex of formula [Ag 6 (μ 2 ‐Br) 6 (μ 2 ‐StpmH 2 ) 4 (μ 3 ‐StpmH 2 ) 2 ] n ( 1 ), while the reaction of silver( I ) nitrate with StpmH 2 under the same conditions gives a water‐insoluble complex of formula [{Ag 4 (μ 2 ‐StpmH 2 ) 6 }(NO 3 ) 4 ] n ( 2 ). The products were characterized by elemental analyses, and FT‐IR far‐IR, UV/Vis, 1 H and 13 C NMR spectroscopy. Crystal structures of complexes 1 and 2 were determined by X‐ray diffraction. Complex 1 , C 24 H 48 Ag 6 N 12 S 6 , crystallizes in the triclinic system space group P $\bar 1$ , a = 8.041(1) Å, b = 12.838(4) Å, c = 13.281(2) Å, α = 68.40(1)°, β = 72.97(1)°, γ = 87.80(2), Z = 2, forming a one‐dimensional infinite ribbon structure by strong interatomic interactions of two μ 2 ‐Br bonds with Ag(1). Complex 2 , C 24 H 48 Ag 4 N 16 O 12 S 6 , crystallizes in the orthorhombic system, space group Cmc 2 1 , and a = 32.148(3) Å, b = 9.461(2) Å, c = 7.234(1) Å, α = β = γ = 90°, Z = 8, forming infinite Ag−S−Ag chains which are bridged to each other by a sulfur atom of μ 2 ‐StpmH 2 ligands. Complexes 1 and 2 were studied for their cytostatic activity against murine leukemia (L1210) and human T‐lymphocyte (Molt4/C8 and CEM) cells and for their antiviral activity against a wide variety of viruses. They are markedly cytostatic at 50% inhibitory concentration (IC 50 ) values ranging from 3 to 17 μg/mL. None of the compounds showed appreciable antiviral activity at subtoxic concentrations. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)