Important Counteranion Effect on Adsorption Efficacity of Hydrogen Sulfide by Silver(I)-Dithione Coordination Polymers.

Four new coordination polymers (CPs) have been prepared and evaluated for their efficacy in adsorbing hydrogen sulfide. The reactions of the structurally flexible assembling dithione ligand, L, with different silver(I) salts lead to four new metal-organic coordination architectures (CPs I, III, V, and VIII) exhibiting either one- or two-dimensional networks. CP I, 2D-[(Ag2Cl2)L]n, exhibits a linear series of rhomboid (S)2Ag(µ2-Cl)2Ag(S)2 secondary building units (SBUs) where S is one of the thione functions of L, altogether forming a 2D-network. CP III, 2D-[(AgI)L]n, is built upon parallel staircase-shaped 1D-[Ag2(µ3-I)2]n SBUs bridged by S atoms of L that form a 2D-grid. CP V, 2D-[(AgL)(NO3)]n, presents parallel 1D-folded S-shaped [AgL]n+ chains linked by strong argentophilic Ag···Ag interactions, forming a 2D-scaffolding. CP VIII, 1D-[(Ag2L3)(Cr2O7)]n, shows 1D-zigzag [{Ag(η2-µ2,η-µ,µ-L)}2]n2n+ chains accompanied by Cr2O72- counteranions. The adsorption isotherms of H2S gas by these new CPs were examined and compared to those of related CPs [(Ag2Br2)L]n (II), [(AgCN)4L]n (IV), [(Ag2L)(CF3SO3)2]n (VI), and [(Ag2L)(NO3)(ClO4)]n (VII). Among the tested polymers, the 3D-CP IV featuring cyanide anions exhibits the highest adsorption capacity of the CPs studied in this work. In order to determine the reason for this marked difference, density functional theory (DFT) computations were used. All in all, it turns out that the electrostatic interactions (CN-···H-SH) are significantly stronger than the O-···H-SH ones. This investigation provides a valuable conceptual tool for other designs of CPs and MOFs having the purpose of capturing toxic gases.

Simple synthesis of novel magnetic silver polymer nanocomposites with a good separation capacity and intrinsic antibacterial activities with high performance.

Two new coordination polymers namely, [(AgCN)4LS]n (1) and [(AgCN)3LN]n (2), were successfully synthesized by the reaction of AgNO3 and cyanide as a co-anion with LS[1,1'-(hexane-1,4-diyl)bis(3-methylimidazoline-2-thione] and LN[1,1,3,3-tetrakis(3,5-dimethyl-1-pyrazole)propane] ligands in order to use them for the preparation of magnetic nanocomposites with MnFe2O4 nanoparticles by an efficient and facile method. They were then well characterized via numerous techniques, including elemental analysis, FT-IR spectroscopy, TGA, PXRD, SEM, TEM, EDX, VSM, BET, ICP, and single-crystal X-ray diffraction. The considered polymers and their magnetic nanocomposites with nearly the same antibacterial activity demonstrated a highly inhibitive effect on the growth of Gram-negative (Escherichia coli, Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus, Bacillus subtilis) bacteria. By considering the simple separation and recyclable characters of the magnetic nanocomposites, these materials are suitable to be used in biological applications.