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Selected aspects of the biological activity of a series of six nitrate silver(I) complexes with pyridine and (benz)imidazole derivatives were investigated. The present study evaluated the antibacterial activities of the complexes against three Gram-negative strains: Pseudomonas aeruginosa ATCC 15442, Escherichia coli ATCC 25922 and Proteus hauseri ATCC 13315. The results were compared with those of silver nitrate, a silver sulfadiazine drug and appropriate ligands. The most significant antibacterial properties were exerted by silver(I) complexes containing benzimidazole derivatives. The cytotoxic activity of the complexes was examined against B16 (murine melanoma) and 10T1/2 (murine fibroblasts) cells. All of the tested silver(I) compounds were not toxic to fibroblast cells in concentration inhibited cancer cell (B16) viability by 50%, which ranged between 2.44–28.65 µM. The molecular and crystal structure of silver(I) complex of 2,6-di(hydroxymethyl)pyridine was determined by single-crystal X-ray diffraction analysis. The most important features of the crystal packing and intermolecular non-covalent interactions in the Ag(I) complex were quantified via Hirshfeld surface analysis.

The reactions of silver salts AgX [X = OTf (OTf = CF 3 SO 3 ), ClO 4 and BF 4 ] and bis(diphenylphosphino)methane (dppm) with 4,4′-bipyridine (bipy) and its derivations [1,2-di(4-pyridyl)ethane (dpa), 1,2-di(4-pyridyl)ethylene (dpe), 1,3-bis(4-pyridyl)propane (bpp)] lead to six silver(I) complexes: {[Ag 2 (dppm) 2 (OTf)] 2 (μ-bipy)}(OTf) 2 ·2CH 3 OH ( 1 ), {[Ag 2 (dppm) 2 (μ-bpp)(OTf)](OTf)·CH 3 OH} n ( 2 ), {[Ag 2 (dppm) 2 (CH 3 CN)] 2 (μ-dpa)}(ClO 4 ) 4 ·2CH 3 CN ( 3 ), [Ag 2 (dppm) 3 ](ClO 4 ) 2 ( 4 ), {[Ag 2 (dppm) 2 (μ-bipy)(CH 3 CN)](BF 4 ) 2 } n ( 5 ) and {[Ag 2 (dppm) 2 (μ-dpe)(CH 3 CN)](BF 4 ) 2 } n ( 6 ). Complexes 1 and 3 are tetranuclear complexes with two eight-membered Ag 2 P 4 C 2 rings bridged by bipy and dpa respectively. 2 , 5 and 6 are of infinite chain structures formed by [Ag 2 (dppm) 2 ] units linked by bpp, bipy and dpe respectively. 4 is a binuclear compound with two silver atoms bridged by three dppm ligands. All complexes are characterized by X-ray diffraction, fluorescence, 1 H and 31 P NMR spectroscopy and terahertz time-domain spectroscopy (THz-TDS). [ABSTRACT FROM AUTHOR]

The anion effects on the formation and photoluminescence (PL) of a series of AgX (X − = NO 2 − , NO 3 − , ClO 4 − , and PF 6 − ) compounds with naphthalene-2,3-diyl-diisonicotinate (L) were investigated. According to the single-crystal X-ray structures, the NO 2 − , NO 3 − , and ClO 4 − anions act as anionic ligands rather than as simple counteranions whereas the PF 6 − anion acts as a simple counteranion. Correspondingly, the dinitroargentate anionic species, Ag(NO 2 ) 2 − , was observed in the solid state. The PL intensity of the present compounds, moreover, was proportional to the Ag⋯X distance, namely the metallophilicity of the anions. The weak- or non-coordinating anions, ClO 4 − and PF 6 − , could be smoothly exchanged with the NO 2 − or NO 3 − anion, whereas the reverse exchanges did not occur. The compounds’ physicochemical properties were characterized by means of infrared (IR) spectroscopy, thermogravimetric analysis (TGA)/differential scanning calorimetry (DSC), and PL. [ABSTRACT FROM AUTHOR]

Four different-anion Ag(I) compounds with the ligand norharmane ( 9H -Pyrido[3,4- b ]indole; Hnor) and having the general formula [Ag(Hnor) 2 ](anion) (anion = ClO 4 − , NO 3 − and BF 4 − ) [Ag(Hnor) 2 (MeCN)](PF 6 ) are reported, and studied in detail regarding their coordination mode and in vitro antiproliferative effects. X-ray structural analysis revealed that the complex with the PF 6 − anion has a MeCN solvent molecule weakly coordinated to Ag(I), making the metal coordination T-shaped, while the other compounds present the classical linear Ag(I) coordination. The compounds showed certain cell growth inhibitory effects in two different cancer cell lines, with the perchlorate containing complex being the most toxic and in fact comparable to cisplatin. Notably, the compounds are stable in visible light; and the luminescence in the solid state was found to be extremely weak, whereas in MeOH solution all compounds show a moderate to weak emission band at 375 nm, when excited at 290 nm. [ABSTRACT FROM AUTHOR]

To systematically explore the influence of pyridazine ligands and aromatic polycarboxylate on the existence of argentophilicity, four inorganic–organic hybrid Ag(I) complexes were obtained by one-pot ultrasonic reaction. Four complexes were named [Ag 6 (pdz) 2 (btc) 2 ] n ( 1 ), [Ag 2 (pdz)(npt)] n ( 2 ), [Ag 2 (pdz)(pma) 1/2 ] n ( 3 ), and [Ag 2 (pdz)(npa)·H 2 O] n ( 4 ) (pdz = pyridazine, H 3 btc = 1,3,5-benzene tricarboxylic, H 2 npt = 3-nitrophthalic acid, H 4 pma = pyromellitic acid, H 2 npa = 1,4-naphthalenedicarboxylic acid). Structural analyses reveal that complexes 1 – 4 display diverse 2D or 3D frameworks, which all of the N-donor pdz ligands exhibit the same coordination mode but the distances of the silver atoms which link to the pdz ligands are different to each other. Complex 1 shows Ag 6 clusters and the cluster is comprised by two distorted tetrahedron silver units. And the clusters are shared by two silver ions to form 1D silver chains. Complex 2 features 1D silver chains which are formed by the Ag 4 units and the four Ag(I) ions are in the vertices of parallelogram. Complex 3 is an interpenetrating architecture with the pdz ligands alternately repeating up and down in ac plane. The structure of complex 4 is a 2D layer structure which the pdz and npt ligands alternately repeat along a axis. Moreover, complexes 1 – 4 indicate different photoluminescence behaviors in the solid state. [ABSTRACT FROM AUTHOR]

Ligands of type [R2C(OH)CH2](2-Me2NCH2C6H4)E [R = Me, E = S (1), Se (2), Te (3); R = Ph, E = S (4), Se (5)] were obtained in the reactions of (2-Me2NCH2C6H4)ELi and the corresponding R2C(OH)CH2Cl (R = Me, Ph) reagent. The reactions between the ligands 1-3 and 5 with AgOTf (OTf = OSO2CF3), in a 1:1 M ratio, resulted in the silver(I) complexes [AgOTf{E[CH2C(OH)R2](C6H4CH2NMe2-2)}] [R = Me, E = S (6), Se (7), Te (8); R = Ph, E = Se (9)]. The new compounds 1-9 were investigated by solution NMR spectroscopy (¹H, 19F, 77Se, 125Te, as appropriate). The ligands 1-5 were investigated also by 13C NMR. The IR spectra and the molar conductivity of the silver(I) complexes suggested a covalent nature of the Ag-OTf bond, while their ESI + MS spectra suggest the formation of dimeric species. Single crystal X-ray diffraction studies revealed a monomeric structure with intramolecular N⋯H-O hydrogen bonding for compound 5, while for the complex 6 dimeric associations formed by bridging ligands were found. [ABSTRACT FROM AUTHOR]

Four new coordination complexes with silver(I) ions and nitrogenous aromatic heterocyclic carboxylic ligands, namely [Ag4(pztc)(phen)4]·8H2O (1), {[Ag4(pztc)(bpe)3]·5H2O}n (2), [Ag4(Hmptc)2(4,4′-bpy)3]·4.5H2O (3), and [Ag2(H2mptc)2(2,2′-bpy)2] (4) (H4pztc=pyrazine-2,3,5,6-tetracarboxylic acid, H3mptc=6-methyl-2,3,5-pyridine-tricarboxylic acid, phen=1,10-phenanthroline, bpe=trans-1,2-bis(4-pyridyl)ethylene, 4,4′-bpy=4,4′-bipyridine, 2,2′-bpy=2,2′-bipyridine), have been synthesized by the self-assembly reactions and characterized by X-ray diffraction single crystal structure analysis, elemental analysis, IR, PXRD, fluorescence and thermal analysis. In 1, four crystallographically independent silver(I) atoms are found to coordinate with only one pztc4− ligand. Complex 2 is a 2D grid structure. Complexes 3 and 4 are extended from 0D to 2D or 1D by the Ag⋯O interactions. [ABSTRACT FROM AUTHOR]

Highlights: [•] Two silver(I) CPs of pyd (2,3-pyridinedicarboxylic acid) were synthesized and characterized. [•] The structure of complex 1 exhibits a novel 1D Ag···Ag silver-wire structure in 2D layer structure. [•] Complex 2 presents 3D supramolecular framework with different coordination modes of pyd ligand. [•] The photoluminescence behaviors of the complexes were discussed. [ABSTRACT FROM AUTHOR]

Abstract: The new mixed ligand silver(I) complex of formula [AgI(TPP)2(MBZT)] (1) was obtained by reacting 2-mercapto-benzothiazole (MBZT) with triphenylphosphine (TPP). The complex was characterized by m.p., vibrational spectroscopy (FT-IR), 1H NMR, UV–vis, ESI-MS spectroscopic techniques and its structure was confirmed by X-ray crystallography. Mixed ligand complexes of silver(I) iodide with thiones and phosphines are very rare in the literature and to the best of our knowledge compound 1 is the first of this kind exhibiting significant biological effects. Complex 1 was evaluated for its in vitro cytotoxic activity (cell viability) under irradiation with UV light and without irradiation against human cancer cell lines: MCF-7 (breast, ER positive), MDA-MB-231 (breast, ER negative), Caki-1 (renal), A549 (lung), OAW-42 (ovarian), HeLa (cervical) and additionally against the normal human lung cell line MRC-5 (normal human fetal lung fibroblast cells) and normal immortalized human mammary gland epithelial cell line (MTSV17) with SRB assay. The results showed that 1 mediates a strong cytotoxic response to the tested normal and cancer cell lines. It exhibits equal activity against MDA-MB-231 cells where estrogen receptors (ERs) are devoid with the one against MCF-7 where ERs are present. Molecular docking studies have shown that 1 is docked in the different pocket than that of the ERs modulators. The binding affinity of 1 towards the intracellular molecules DNA and lipoxygenase (LOX) was studied for the evaluation of the mechanism of its cytostasis. The binding constant (K b ) of 1 towards CT-DNA was calculated by UV–Vis and fluorescent spectra suggesting intercalation or electrostatic interactions of 1 into DNA. Docking studies on DNA-complex interactions confirm the binding of 1. Moreover, the influence of complex 1 on the catalytic peroxidation of linoleic acid to hydroperoxylinoleic acid by the enzyme lipoxygenase (LOX) was kinetically and theoretically studied. In addition, since the deactivation of cisplatin caused by glutathione, seems to be an important determinant of its cytotoxic effects, the reaction of 1 with glutathione (GSH) was investigated by UV-absorption spectroscopy. [Copyright &y& Elsevier]

The title compounds, bis{μ- N-[(diphenylphosphanyl)methyl]pyridin-4-amine-κ2 N1: P}disilver bis(perchlorate) acetonitrile monosolvate, [Ag2(C18H17N2P)2](ClO4)2·CH3CN, (1), and bis{μ- N-[(diphenylphosphanyl)methyl]pyridin-4-amine-κ2 N1: P}bis[(nitrato-κ2 O, O)silver], [Ag2(C18H17N2P)2(NO3)2], (2), each contain disilver macrocyclic [Ag2(C18H17N2P)2]2+ cations lying about inversion centres. The cations are constructed by two N-[(diphenylphosphanyl)methyl]pyridin-4-amine (DPP) ligands linking two Ag+ cations in a head-to-tail fashion. In (1), the unique Ag+ cation has a near-linear coordination geometry consisting of one pyridine N atom and one P atom from two different DPP ligands. Two ClO4− anions doubly bridge two metallomacrocycles through Ag...O and N-H...O weak interactions to form a chain extending in the c direction. The half-occupancy acetonitrile molecule lies with its methyl C atom on a twofold axis and makes a weak N...Ag contact. In (2), there are two independent [Ag(C18H17N2P)]+ cations. The nitrate anions weakly chelate to each Ag+ cation, leading to each Ag+ cation having a distorted tetrahedral coordination geometry consisting of one pyridine N atom and one P atom from two different DPP ligands, and two chelating nitrate O atoms. Each dinuclear [Ag2(C18H17N2P)2(NO3)2] molecule acts as a four-node to bridge four adjacent equivalent molecules through N-H...O interactions, forming a two-dimensional sheet parallel to the bc plane. Each sheet contains dinuclear molecules involving just Ag1 or Ag2 and these two types of sheet are stacked in an alternating fashion. The sheets containing Ag1 all lie near x = , , etc, while those containing Ag2 all lie near x = 0, 1, 2 etc. Thus, the two independent sheets are arranged in an alternating sequence at x = 0, , 1, etc. These two different supramolecular structures result from the different geometric conformations of the templating anions which direct the self-assembly of the cations and anions. [ABSTRACT FROM AUTHOR]

Silver(I) pyridinecarboxylates (AgPIC (1), AgNIC (2), [Ag(HDIPIC)]?0.75H2O (3), PIC?=?picolinate, NIC?=?nicotinate, HDIPIC?=?dipicolinate) were prepared by solvothermal syntheses and their characterization were completed by elemental, spectral, and thermal analyses. To assign the pyridinecarboxylate coordination mode in the complexes, detailed mid-infrared spectral data and ?(?as????s) comparisons were accomplished. In addition, silver(I) pyridinecarboxylate antimicrobial activities and stability by1H NMR spectra were determined. Moreover, the spectral, thermal, and antimicrobial properties of silver(I) and previously prepared zinc(II) pyridinecarboxylates were compared and discussed. [ABSTRACT FROM PUBLISHER]

P-coordinated complexes of the type [AgNO3{Ph2P(CH2)nPPh2C(H)C(O)C6H4R}]2 (n = 1 or 2; R=Cl, Br, NO2 or OCH3), have been synthesised by reactions of AgNO3 with the appropriate phosphorus ylides. The antibacterial effects of DMSO-solutions of all compounds have been evaluated by the agar disc diffusion method against six Gram positive and Gram negative bacteria. [ABSTRACT FROM AUTHOR]

Highlights: [•] Two new cyanoxime ligands and their precursors were synthesized. [•] Compounds were characterized using NMR, UV–Vis spectra, X-ray analysis. [•] Two new light-stable silver(I) cyanoximates were obtained and characterized. [•] Acrylate-based polymeric composites containing Ag(I) cyanoximates were prepared. [•] Antimicrobial activity and biofilm inhibition of two silver(I) complexes was established. [ABSTRACT FROM AUTHOR]

Abstract: Three mononuclear silver(I) complexes with 8-hydroxyquinoline, 8-hydroxy-2-methylquinoline and 5-chloro-8-quinolinol were synthesized and characterized by elemental analysis, NMR, ESI-MS as well as single crystal X-ray diffraction analysis. All the structures of complexes 1–3 with the silver center adopting an approximately four-coordinated distorted tetragonal pyramid geometry were found to exhibit selective cytotoxicity against HepG2, NCI-H460, BEL-7404 and HeLa cell lines with IC50 values generally in the micromolar range (1.7–14.6μM), but low cytotoxicity towards normal human liver cell HL-7702. A combination of flow cytometric analysis and molecular probe observation indicated that complexes 1–3 could induce HepG2 cell apoptosis. Molecular mechanism studies suggested that complexes 1–3-induced apoptosis is mediated through the intrinsic apoptotic pathway with changes in mitochondrial membrane potential by finally activating effector caspase-3/9 to trigger cell apoptosis. Further studies revealed that complexes 1 and 2 caused cell cycle arrest at S phase, while complex 3 induced G1 cell cycle arrest in HepG2 cells. Taken together, these results suggest that complexes 1–3 may be potential candidates for cancer therapy. [Copyright &y& Elsevier]

Abstract: Heteronuclear complexes of the type [AgAu(PPh3)2(xspa)] [H2 xspa=3-(aryl)-2-sulfanylpropenoic acids; (x =3-phenyl-; 3-(2-chlorophenyl)-; 3-(o-methoxyphenyl)-; 3-(p-methoxyphenyl)-; 3-(p-hydroxyphenyl)-; 3-(2-furyl)-; 3-(2-thienyl)-; spa=2-sulfanylpropenoate)] were prepared by reacting the appropriate [Au(PPh3)(Hxspa)] precursor with Ag(PPh3)NO3. The compounds were characterized by spectroscopic methods, (IR; 1H, 13C and 31P NMR) and mass spectrometry and the structures of the phenyl and p-methoxyphenyl derivatives were determined by X-ray diffraction. The in vitro antitumor activity against the HeLa-229, A2780 and A2780cis cell lines was determined and compared with that of cisplatin and the equivalent homonuclear gold(I) complexes. [Copyright &y& Elsevier]

A series of new silver(I) saccharinate (sac) complexes, [Ag(sac)(μ-dppm)HO]·HO ( 1), {[Ag(μ-sac)(μ-dppe)]·3HO·CHCl} ( 2), [Ag(μ-sac)(μ-dppp)] ( 3), and [Ag(sac)(μ-dppb)] ( 4) [dppm is 1,1-bis(diphenylphosphino)methane, dppe is 1,2-bis(diphenylphosphino)ethane, dppp is 1,3-bis(diphenylphosphino)propane, and dppb is 1,4-bis(diphenylphosphino)butane], have been synthesized and characterized by C, H, N elemental analysis, IR spectroscopy, H NMR, C NMR, and P NMR spectroscopy, electrospray ionization mass spectrometry, and thermogravimetry-differential thermal analysis. Single-crystal X-ray studies show that the diphosphanes act as bridging ligands to yield a dinuclear complex ( 1) and one-dimensional coordination polymers ( 2 and 4), whereas the sac ligand adopts a μ-N/O bridging mode in 2, and is N-coordinated in 1 and 4. The interaction of the silver(I) complexes with fish sperm DNA was investigated using UV-vis spectroscopy, fluorescence spectroscopy, and agarose gel electrophoresis. The binding studies indicate that the silver(I) complexes can interact with fish sperm DNA through intercalation, and complexes 1 and 3 have the highest binding affinity. The gel electrophoresis assay further confirms the binding of the complexes with the pBR322 plasmid DNA. The minimum inhibitory concentrations of the complexes indicate that complex 1 exhibits very high antibacterial activity against standard bacterial strains of Escherichia coli, Salmonella typhimurium, and Staphylococcus aureus, being much higher than those of AgNO, silver sulfadiazine, ciprofloxacin, and gentamicin. Moreover, complexes 1- 3 exhibit very high cytotoxic activity against A549 and MCF-7 cancer cell lines, compared with AgNO and cisplatin. The bacterial and cell growth inhibitions of the silver(I) complexes are closely related to their DNA binding affinities. [ABSTRACT FROM AUTHOR]

Abstract: Three new silver(I) complexes of 4-(hydroxymethyl)pyridine (4-CH2OHpy), 2,6-di(hydroxymethyl)pyridine (2,6-di(CH2OH)py) and 2-(hydroxymethyl)benzimidazole (2-CH2OHbim) were synthesized. These complexes, with the general formula [Ag(L)2]NO3, were characterized by IR, NMR (1H and 13C) spectroscopy and elemental analysis. ESI-MS spectrometry was used in some cases. The crystal structure of [Ag(4-CH2OHpy)2]NO3 was determined by single crystal X-ray diffraction analysis. The complex demonstrates the slightly bent N1–Ag1–N2 coordination geometry (167.22(4)°) and consists of one nitrate anion and one silver ion coordinated by two 4-(hydroxymethyl)pyridine (4-CH2OHpy) ligands via N atoms. The series of three silver(I) complexes and the corresponding free ligands was tested for their antibacterial and antifungal activities, screened in vitro against Staphylococcus aureus ATCC 6538, Staphylococcus epidermidis ATCC 12228 and Candida albicans ATCC 10231. All the silver(I) complexes demonstrated considerable activity, especially against C. albicans (with MIC values 10–20 mg l−1). [Copyright &y& Elsevier]

Highlights: [•] A unique supra-channel structure was constructed via molecular array of a 1D strand. [•] Weak C–H⋯π interactions result in the formation of square supra-channel structures. [•] Anion exchangeability and thermolysis are strongly affected by the nature of anions. [•] Anion exchange of [Ag(L)](BF4) with NaClO4 occurs smoothly. [•] Calcination of [Ag(L)](ClO4) crystals produce the Ag(0)/AgCl/SiO2 composite. [Copyright &y& Elsevier]

Abstract: The novel N-heterocyclic carbene ligand precursor NaHImPrSO3 (sodium 3,3′-(1H-imidazole-3-ium-1,3-diyl)dipropane-1-sulfonate) and the related silver carbene complex [Na4(ImPrSO3)2]AgCl have been synthesized and characterized. Recrystallization of the analogous [ImAcEt]AgCl complex allowed the development of X-ray analysis which led to achieve relevant structural information concerning this silver(I) derivative. Both sulfonate- and ester-functionalized silver(I) N-heterocyclic carbenes (NHCs) were evaluated for their antiproliferative activities in a wide panel of human cancer cells. Complex [Na4(ImPrSO3)2]AgCl showed a significant in vitro antiproliferative activity that was correlated with its strong ability to inhibit thioredoxin reductase. The inhibition of this selenoenzyme determined an alteration of the cellular redox environment thus leading to the induction of the apoptotic cell death through the activation of the ASK-1 pathway. [Copyright &y& Elsevier]

A series of silver(I) complexes of the general composition {[Ag( μ2- RBap)]· yH 2O} n ( y = 0 or 0.5), involving the deprotonated forms of the 6-(benzylamino)purine derivatives ( RBap), was prepared. The compounds were characterized by elemental analysis (C, H, N), Raman and FT-IR spectroscopy, TG/DTA thermal analyses, and X-ray powder diffraction. On the basis of the fact that we were not able to prepare single crystals suitable for X-ray analysis, although many attempts at different conditions were made, DFT calculations were used for the prediction of structural properties of the complexes. The calculations implied a bridging coordination of the RBap ligands to Ag(I) via the N1 and N9 atoms of the purine moieties and thus the formation of 1D polymeric chain structure involving the Ag(N1)(N9) donor set. The products of thermal decomposition of selected complexes were characterized by scanning electron microscopy combined with energy-dispersive X-ray spectroscopy, and they were determined as silver aggregates with the average size of ~10 μm. Graphical abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

A family of three- and four-coordinated silver(I) complexes of formulas [Ag(PPh 3 ) 2 L], [Ag(PPh 3 )L], and [AgL] n with N-thiophosphorylated thiourea and thioamide ligands of general formula RC(S)NHP(S)(OPri) 2 [R = Ph, PhNH, iPrNH, tBuNH, NH 2 ] have been studied by solid-state 109 Ag and 31 P CPMAS NMR spectroscopy. 109 Ag NMR spectra have provided valuable structural information about Ag coordination, which is in good accordance with the available crystal structure data. The data presented in this work represent a significant addition to the available 109 Ag chemical shifts and chemical shifts anisotropies. The silver chemical shift ranges for different P,S-environments and coordination state were discussed in detail. The 1 J( 31 P- 107/109 Ag) and 2 J( 31 P- 31 P) values were determined and analyzed., (© 2022 John Wiley & Sons Ltd.)

A series of heteroleptic Ag(I) complexes bearing 4,6-dimethyl-2-pyrimidinethiol (dmp2SH), i.e. , [AgCl(dmp2SH)(PPh 3) 2 ] (1), [Ag(dmp2SH)(PPh 3) 2 ]NO 3 (2), [Ag(dmp2SΗ)(xantphos)]NO 3 (3), [Ag(μ-dmp2S)(PPh 3)] 2 (4), [Ag(dmp2S)(xantphos)] (5), [Ag(μ-dmp2S)(DPEphos)] 2 (6) (xantphos = 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene and DPEPhos = bis[(2-diphenylphosphino)phenyl]ether) were synthesized. The complexes display systematic variation of particular structural characteristics which were proved to have a significant impact on their in vitro cytotoxicity and antimicrobial properties. A moderate-to-high potential for bacteria growth inhibition was observed for all complexes, with 2 , 3 and 5 being particularly effective against Gram-(+) bacteria (IC 50 = 1.6–4.5 μM). The three complexes exhibit high in vitro cytotoxicity against HeLa and MCF-7 cancer cells (IC 50 = 0.32–3.00 μΜ), suggesting the importance of coordination unsaturation and cationic charge for effective bioactivity. A very low cytotoxicity against HDFa normal cells was observed, revealing a high degree of selectivity (selectivity index ~10) and, hence, biocompatibility. Fluorescence microscopy using 2 showed effective targeting on the membrane of the HeLa cancer cells, subsequently inducing cell death. Binding of the complexes to serum albumin proteins is reasonably strong for potential uptake and subsequent release to target sites. A moderate in vitro antioxidant capacity for free radicals scavenging was observed and a low potential to destroy the double-strand structure of calf-thymus DNA by intercalation, suggesting likely implication of these properties in the bioactivity mechanisms of these complexes. Further insight into possible mechanisms of bioactivity was obtained by molecular modeling calculations, by exploring their ability to act as potential inhibitors of DNA-gyrase, human estrogen receptor alpha, human cyclin-dependent kinase 6, and human papillomavirus E6 oncoprotein. A series of Ag(I) compounds bearing a heterocyclic thioamide and phosphine ligands were synthesized. Cationic and coordinatively unsaturated compounds exhibit high in vitro antimicrobial potency as well as high and selective to healthy cells in vitro cytotoxicity. In silico investigations shed light on their possible mechanisms of action. [Display omitted] • Ag(I) coordination compounds; heterocyclic thioamides and phosphine ligands • High in vitro antimicrobial potency • High in vitro cytotoxicity; HeLa and MCF-7 cancer cells; selectivity to healthy cells • Interaction with DNA and serum albumins; antioxidant activity • Molecular docking; chemo-informatics analysis and drug-likeness [ABSTRACT FROM AUTHOR]

Abstract: The reactions of triphenylphosphine (PPh3) and 4,4′-bipyridine (bipy), 1,2-di(4-pyridyl)ethane (dpa), 1,3-bis(4-pyridyl)propane (bpp) ligands with AgX (X=BF4 and NO2) lead to five new complexes: {[Ag(PPh3)2(bpp)](BF4)} n (1), [Ag(dpa)(BF4)] n (2), {[Ag(PPh3)2(μ-bipy)]2(BF4)2} n (3) and {[Ag(PPh3)2(CH3CN)]2(μ-bipy)}(BF4)2 (4) and [Ag(dpa)(NO2)] n (5). In 1, 2 and 3, the Ag atoms are bridged by pyridyl-containing ligands (bpp, dpa and bipy, respectively) to form infinite chain structure. In 4, the Ag atoms are bridged by bipyridine to form a dinuclear structure. Complex 5 is of layer structure which is formed by silver atoms, oxygen atoms from NO2 − and dpa. All the complexes are characterized by X-ray diffraction, fluorescence and 1H NMR spectroscopy. [Copyright &y& Elsevier]

Abstract: The biological activity of some new mixed silver–phosphane–thio-ligand complexes, with 1:1:2, 1:1:1 and 1:2:1 (Ag:phospine:ligand) compositions, have been examined. Ten compounds were prepared using a series of silver(I) salts [AgX, where X=NO3, ClO4, PF6 and Br], tertiary phosphines and the ligands thiosemicarbazide, 2-(propan-2-ylidene)hydrazinecarbothioamide, and thiazolidine-2-thione. The syntheses were carried out under ambient conditions, and the ten complexes obtained were found to be light stable. All 10 compounds were characterized by elemental analysis, FTIR, and NMR spectroscopy, whereas nine compounds were characterized by X-ray diffraction analysis. The anti-proliferative activities were evaluated by minimum inhibitory concentration (MIC: μg/mL) in an aqueous suspension system and they all show promising potential activity against selective strains of Gram-positive and Gram-negative bacteria, fungous and Mycrobaterium tuberculosis H37Rv. [Copyright &y& Elsevier]

Highlights: [•] Coordination polymers of Cu(I) and Ag(I) of polydentate imino-pyridyl ligands have been reported. [•] These coordination assemblies are of various dimensionalities. [•] Photophysical properties of these coordination polymers have been presented. [•] Cu2I2 has been used as secondary building unit. [Copyright &y& Elsevier]

Abstract: Six Ag(I) coordination compounds containing pyridyl carboxylates [namely of trans-3-(3′-pyridyl) acrylic acid (3-PAH), trans-3-(4′-pyridyl) acrylic acid (4-PAH), and 4-trans-2-(pyrid-4-yl-vynyl) benzoic acid (Hpvba)] and phosphine ligands [namely triphenylphosphine, 1,1-bis-(diphenylphosphino) methane (dppm), 1,2-bis-(diphenylphosphino) ethane (dppe) and 1,3-bis-(diphenylphosphino) propane (dppp)] are described. By varying the combination of silver salts and bridging ligands, we have synthesized 0D, 1D, 2D and 3D architectures of silver(I) coordination compounds and polymers. The coordination environments and geometries around Ag(I) are highly dependent on the coordination mode of carboxylate ‘O’ (whether monodentate, μ1,1 or μ1,3). On the other hand, the dimensionality of the coordination polymers depends on the bridging diphosphine ligands and shape of the pyridyl carboxylates. [Copyright &y& Elsevier]

Abstract: A chiral coordination polymer of L-argininesilver(1+) nitrate, {{[Ag(L-Harg)](NO3)}2·H2O} n (1) was prepared by vapor diffusion using a water-methanol mixed solution containing AgNO3 and neutral L-arginine (L-Harg) as the inner solution and ether as the external solvent, followed by characterization by CHN analysis, FTIR, TG/DTA, single-crystal X-ray analysis and (1H and 13C) NMR spectroscopy. In the crystal, each silver(I) ion was coordinated by Namino of one L-Harg and Ocarboxy of the other. Linear polymer chains consisting of repeating Namino–Ag–Ocarboxy bonding units were connected by Ag…Ag (3.0440(5)Å) interaction and intermolecular hydrogen bonding to form a grid-like sheet. The sheets were connected by hydrogen bonds and electrostatic interaction between guanidium groups and NO3 −. The antimicrobial activities of 1 against selected bacteria, yeasts and molds were evaluated by minimum inhibitory concentration (MIC). Complex 1 inhibited growth of four bacteria (Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and Staphylococcus aureus) and a yeast (Saccharomyces cerevisiae) moderately, the spectrum of which is different from that of AgNO3. [Copyright &y& Elsevier]

Six silver(I) coordination complexes have been prepared and structurally characterised. Mixed chalcogen-donor acenaphthene ligands L1-L3 [Acenap(EPh)(E'Ph)] (Acenap = acenaphthene-5,6-diyl; E/E' = S, Se, Te) were independently treated with silver(I) salts (AgBF4/AgOTf). In order to keep the number of variables to a minimum, all reactions were carried out using a 1:1 ratio of Ag/L and run in dichloromethane. The nature of the donor atoms, the coordinating ability of the respective counter-anion and the type of solvent used in recrystallisation, all affect the structural architecture of the final silver(I) complex, generating monomeric, silver(I) complexes {[AgBF4(L)2] (1 L = L1; 2 L = L2; 3 L = L3), [AgOTf(L)3] (4 L = L1; 5 L = L3), [AgBF4(L)3] (2a L = L1; 3a L = L3)} and a 1D polymeric chain {[AgOTf(L3)]n 6}. The organic acenaphthene ligands L1-L3 adopt a number of ligation modes (bis-monodentate μ2-η2-bridging, quasi-chelating combining monodentate and η6-E(phenyl)-Ag(I) and classical monodentate coordination) with the central silver atom at the centre of a tetrahedral or trigonal planar coordination geometry in each case. The importance of weak interactions in the formation of metal-organic structures is also highlighted by the number of short non-covalent contacts present within each complex. [ABSTRACT FROM AUTHOR]

Abstract: Six new coordination complexes [Ag2(L)2](NO3)2 (1), [Ag2(L)2](ClO4)2 (2), [Ag3(L)4](SbF6)3 (3), [Ag2(L)2(CH3CN)2](PF6)2 (4), [Ag2(L)2(SO3CH3)2](CH3OH)2 (5) and [Ag2(L)2(SO3CF3)2] (6) were successfully synthesized by reactions of 1,3-bis(2-oxazolinyl)benzene (L) with different Ag(I) salts under the same reaction conditions. Complexes 1 and 2 have the same 16-membered ring structures, which are extended by Ag···O weak interactions and hydrogen bonds to form 3D frameworks. Complex 3 containing two- and four-coordinated Ag(I) atoms has two inter-connected 16-membered rings which are linked together by to form a 3D framework. In complex 4, the Ag(I) is three-coordinated by two N atoms from the L ligands and one N atom from acetonitrile solvent and the structure of 4 is also a 16-membered ring. Complexes 5 and 6 have similar 16-member ring structure, and the anions coordinate with Ag(I) atoms. The results reveal that anions can influence on the structure of the complexes. Furthermore, the complexes were characterized by electrospray mass spectrometry. [Copyright &y& Elsevier]

Abstract: The self-assembly of silver(I) salts (AgAsF6, AgCF3CO2) with the bitopic triazole ligand 4-(2-pyridinyl)-1,2,4-triazole (L1) produced two dinuclear complexes [Ag(L1)2]2(AsF6)2·3H2O (1) and [Ag(L1)(CF3CO2)(H2O)]2 (2). While the reaction of the tritopic ligand 4-(3-pyridinyl)-1,2,4-triazole (L2) with AgCF3SO3 and AgCH3CO2 afforded the two-dimensional meso {[Ag2(L2)2(CF3SO3)2]·0.5H2O} n (3) and, containing alternative left- and right-handed helical chains and an infinite two-dimensional architecture, {[Ag(L2)](CH3CO2)·0.75H2O} n (4) with 4.82 topology. Structural analyses indicate that the increase of coordination number (from 2 to 3) of the ligand is an effective route to obtain high-dimensional structures (from zero- to two-dimensional). Moreover, the anions not only play an important role in the outcome of the resulting supramolecular array, but also greatly influence the configurations of the ligands to tune the coordination network topology. Both in the solid state and in aqueous solution, all four complexes exhibit strong fluorescent emission bands, which may be assigned to intra-ligand fluorescent emissions. [Copyright &y& Elsevier]

Abstract: Silver(I) complexes [Ag2(L)4](NO3)2 were synthesized by the reaction of AgNO3 with 2-hydroxymethyl-N-alkylimidazoles (L) (alkyl=benzyl, methyl, ethyl, propyl, butyl, heptyl, octyl and decyl) in ethanol at room temperature. The X-ray crystal structures of [Ag2(2-hydroxymethyl-N-ethylimidazole)4](NO3)2 (C2) showed a dimeric [Ag(L)4](NO3)2 and a monomeric [Ag(L)2]NO3 complex (L=2-hydroxymethyl-N-ethylimidazole) in its unit cell, while [Ag2(2-hydroxymethyl-N-benzylimidazole)4](NO3)2 (C8) showed only a dimeric complex [Ag2(L)4](NO3)2 (L=2-hydroxymethyl-N-benzylimidazole). Both complexes displayed a slightly distorted linear N–Ag–N arrangement and the presence of Ag–Ag interactions in the dimeric complexes was due to the π stacking of the imidazole moieties. The antimicrobial properties of the Ag(I) complexes were investigated against Escherichia coli, Staphylococcus aureus, Bacillus spizizenii and Candida albicans by the disk diffusion and the broth microdilution methods. The Ag(I) complexes containing 2-hydromethyl-N-alkylimidazole ligands with shorter alkyl chain length were predominantly active against E. coli. The complexes containing ligands with longer alkyl chain length displayed predominant activity against B. spizizenii. The broad spectrum antimicrobial activity displayed by these silver(I) complexes makes them potential alternatives to the commercially available antimicrobial agents. [Copyright &y& Elsevier]

Some new Schiff bases, ( Z)-4-amino-3-(( E)-( R-methoxybenzylidene)hydrazono)-6-methyl-3,4-dihydro-1,2,4-triazin-5( 2H)-one ( R = 2 ( L2), R = 3 ( L3) and R = 4 ( L4)), were synthesized by the condensation reactions of 4-amino-3-hydrazinyl-6-methyl-1,2,4-triazin-5( 4H)-one ( L1) and corresponding methoxybenzaldehyde in a molar ratio 1:1.5 in high yields. The reaction of L2 and L4 with an excess amount of the corresponding aldehydes gave the unsymmetrical bis-Schiff bases ( E)-3-(( E)-( R-methoxybenzylidene)hydrazono)-4-(( E)- R-methoxybenzylideneamino)-6-methyl-3,4-dihydro-1,2,4-triazin-5( 2H)-one ( R = 2 ( L22) and R = 4 ( L44)), respectively. Furthermore, the reaction of L2- L4 with silver(I) nitrate in a molar ratio 2:1 led to the silver(I)-complexes with the general formula [Ag( Lx)]NO ( Lx = L2 ( 2), L3 ( 3) and L4 ( 4)). All synthesized Schiff base compounds and complexes were characterized by a combination of IR-, H-NMR spectroscopy, mass spectrometry and elemental analyses. In addition, the structures of L2, L4·CHCN, L22·CHOH and L44·CHOH and complexes 2 and 4 were determined by X-ray diffraction studies. [ABSTRACT FROM AUTHOR]

Abstract: Reactions of new α-ketostabilized phosphorus ylides of the type Ph3P=CHC(O)R (R=2,4-dichlorophenyl (L1 ) and 4-isopropylphenyl (L2 )) with AgNO3and Hg(NO3)2.H2O, using methanol as a solvent, are reported. The crystal structures of L2 and [Ag(L2)2(NO3)] (2) have been determined. Characterization of the obtained compounds was also performed by elemental analysis, IR, 1H, 31P and 13C NMR. Theoretical studies were carried out on the silver(I) complexes. It was shown that the nitrate ion shows a bonding interaction with the silver ion. [Copyright &y& Elsevier]

Abstract: Direct reaction of copper(I) chloride with 2-mercaptopyrimidine (pmtH) in the presence of the triphenylphosphine (tpp) in 1:1:2M ratio forms the mixed ligand Cu(I) complex with formula [CuCl(tpp)2(pmtH)] (1). The dimeric {[Cu(tpp)(pmt)]2 0.5(MeOH)} (2) complex was derived from the reaction of 1 with twofold molar amount of sodium hydroxide. However, the reaction of copper(II) sulfate or nitrate with pmtH and tpp in 1:2:2M ratio, unexpectedly results in the formation of the [CuSH(tpp)2(pmtH)] (3) complex. Further studies have shown that the [Cu(tpp)2(pmt)] (4) complex is formed by reacting copper(II) acetate with pmtH in the presence of tpp in 1:2:2M ratio, while in the absent of tpp, the Cu(CH3COO)2 or CuSO4 is found to oxidizes pmtH to its corresponding disulfide (pmt)2. For comparison the mixed ligand silver(I) chloride or nitrate complexes with formula [AgCl(tpp)2(pmtH)] (5) or [Ag(NO3)(tpp)2(pmtH)] (6) are also synthesized by reacting of the AgCl or AgNO3 with pmtH and tpp in 1:2:2M ratio. The complexes have been characterized by elemental analyses, m.p., vibrational spectroscopy (mid-, far-FT-IR and Raman), 1H NMR, UV–Vis, ESI-MS, TG–DTA spectroscopic techniques and single crystal X-ray crystallography at ambient conditions. Photolysis of 1–6, was also studied and the results showed formation of triphenylphosphine oxide. The complexes 1–6, were used to study their influence upon the catalytic peroxidation of the linoleic acid by the enzyme lipoxygenase (LOX) experimentally and theoretically. The binding of 1–4 with LOX was also investigated by saturation transfer difference 1H NMR experiments (STD). [Copyright &y& Elsevier]

Abstract: Two new mixed ligand silver(I) complexes of formulae {[Ag(tpp)3(asp)](dmf)} (1) (aspH=o-acetylsalicylic acid and tpp=triphenylphosphine) and [Ag(tpp)2(o-Hbza)] (2) (o-HbzaH=o-hydroxy-benzoic acid) were synthesized and characterized by elemental analyses, spectroscopic techniques and X-ray crystallography at ambient conditions. Three phosphorus and one carboxylic oxygen atoms from a de-protonated aspirin ligand in complex 1 and two phosphorus and two carboxylic oxygen atoms from a chelating o-Hbza anion in complex 2 form a tetrahedral geometry around Ag(I) ions in both complexes. Complexes 1 and 2 and the silver(I) nitrate, tpp, aspNa and o-HbzaH were tested for their in vitro cytotoxic activity against leiomyosarcoma cells (LMS), human breast adenocarcinoma cells (MCF-7) and normal human fetal lung fibroblasts (MRC-5) cells with Thiazolyl Blue Tetrazolium Bromide (MTT) assay. For both cell lines 1 and 2 were found to be more active than cisplatin. Additionally, 1 and 2 exhibit lower activity on cell growth proliferation of MRC-5 cells. The type of LMS cell death caused by 1 and 2 were evaluated in vitro by use of flow cytometry assay. The results show that at concentrations of 1.5 and 1.9μΜ of complex 1, 44.1% and 69.4%, respectively of LMS cells undergo programmed cell death (apoptosis). When LMS cells were treated with 1.6 and 2.3μM of 2, LMS cells death was by 29.6% and 81.3%, respectively apoptotic. Finally, the influence of the complexes 1 and 2, upon the catalytic peroxidation of linoleic acid to hydroperoxylinoleic acid by the enzyme lipoxygenase (LOX) was kinetically and theoretically studied. The binding of 1 and 2 towards LOX was also investigated by Saturation Transfer Difference (STD) 1H NMR experiments. [Copyright &y& Elsevier]

Abstract: The reactions of triphenylphosphine (PPh3) and 2-aminopyrimidine (AMP) ligand with Ag salts in the mixed solvent of methanol (MeOH) and dichloromethane (CH2Cl2) lead to the mono-, di-, and tetranuclear complexes, [Ag(PPh3)(AMP)2](BF4) (1), [Ag2(PPh3)4(AMP)2(SO4)] (2), [Ag4 (PPh3)4(AMP)2(NO3)4]∞ (3) and [Ag4(PPh3)4(AMP)2(Ac)4]∞ (Ac=CH3COO) (4) and [Ag(PPh3)2(HCOO)]·CH2Cl2 (5). Complexes 1 and 2 are of 1D infinite chain structure controlled by intermolecular hydrogen bonds of type (8). In complexes 3 and 4, the 1D infinite chains are formed through the bridging-chelating anions (nitrate for 3 and acetate for 4) and the N,N′-bridging ligand AMP. Five-coordinated modes of Ag(I) are observed in 3 and 4. In the synthesis reaction of complex 5, AMP only acts as catalyst rather than ligand. All the complexes are characterized by X-ray diffraction. Compounds 1–4 are also characterized by fluorescence and 1H, 31P NMR spectroscopy. [Copyright &y& Elsevier]

Abstract: Construction of AgX (X− = and ) with highly flexible N,N,N′,N′-tetrakis(ethylisonicotinoyl)ethylendiamine (L) has been scrutinized for the weak argentophilic, Ag anion, and Ag·solvent interactions. All such complexes afford coordination polymers consisting of 2:1 (Ag(I):L). [Ag2(L)(CH3CN)2](X)2 (X− = and ) and [Ag2(L)(H2O)](BF4)2 are double-stranded 1D, whereas [Ag2(ClO4)2(L)(Me2CO)2] yields a 2D network structure. The molecular construction has been affected by anions, solvents, and the crystallization method. The natures of anion- and solvent-coordination, including the argentophilic interaction play important roles in the formation of skeletal structures. For [Ag2(L)(CH3CN)2](ClO4)2, weakly coordinated solvate acetonitrile reversibly associates and dissociates in the solid state. [Copyright &y& Elsevier]

Abstract: Mixed ligand silver(I) complexes of triphenylphosphine and heterocyclic thiones (imidazolidine-2-thione (Imt), diazinane-2-thione (Diaz) and 2-mercaptopyridine (Mpy)) having the general formulae [(Ph3P)Ag(thione)2]NO3 and [(Ph3P)2Ag(thione)]NO3 were prepared and characterized by elemental analysis, IR and NMR (1H, 13C and 31P) spectroscopic methods. The crystal structure of one of the complexes, [Ag(Ph3P)(Diaz)2]2(NO3)2 (1) was determined by X-ray crystallography. The title complex (1) is dinuclear, having each silver atom coordinated to three thione sulfur atoms of Diaz and to one phosphorus atom of PPh3 in a nearly tetrahedral environment, with an average P–Ag–S bond angle of 108.5°. The spectral data of the complexes are consistent with sulfur coordination of the thiones to silver(I). Antimicrobial activities of the complexes were evaluated by minimum inhibitory concentrations and the results showed that the complexes exhibit a wide range of activity against two gram-negative bacteria (E. coli, P. aeruginosa) and molds (A. niger, P. citrinum), while the activities were poor against yeasts (C. albicans, S. cerevisiae). [Copyright &y& Elsevier]

Abstract: An achiral coordination polymer, [Ag2(D-his)(L-his)] n , DL-1 (Hhis=histidine), was prepared by slow diffusion of two aqueous solutions of chiral complexes, {[Ag(D-his)]2} n (D-2) and {[Ag(L-his)]2} n (L-2). [1] Note: From the viewpoint of pK a, the abbreviation of histidine is changed from H2his to Hhis. Abbreviation of silver histidinates: L-2 and D-2 are water-soluble complexes of L-his and D-his, respectively, L-3 and D-3 are the corresponding water-insoluble complexes, and DL-1 is the water-insoluble meso complex. 1 The crystal structure of DL-1 consists of a linkage of meso-form dimer units through two kinds of Ag⋯Ag contacts. Crystals of the achiral silver(I) histidinate complex DL-1 exhibited different self-assembly from those of chiral helical polymers (D-3 and L-3). The formation of DL-1 from the two aqueous solutions indicated that ligand exchange around silver(I) atoms took place in water. The antimicrobial activities of DL-1 against selected bacteria, yeasts and molds were evaluated by minimum inhibitory concentration (MIC). [Copyright &y& Elsevier]

Abstract: The reaction of tribenzylphosphane (PBn3) with silver(I) halides, AgX (X=Cl, Br and I), afforded the cluster compound, [Ag13I13(PBn3)6 ] (1), a low-yielding ionic salt, [Ag(PBn3)2]8[AgCl3]Cl6·6H2O (2), and a non-stoichiometric compound, Ag∼11.5Br∼11.5(PBn3)16·∼5.5H2O (3). As well, reactions with the appropriate Ag salt and PBn3 in a 1:2M ratio yielded [Ag(PBn3)2]PF6 (4), [Ag(PBn3)2]BF4 (5) and [Ag(PBn3)2Cl]·0.33CHCl3 (6) while [Ag(PBn3)2I] (7) was obtained when the ratio was 4:1. The iodo-cluster 1 has an onion-like structure with an iodide ion at its center surrounded trigonal-prismatically by an inner core of six silver ions. These silver ions are tetrahedrally coordinated to the innermost iodide ion and by six iodides that bridge to an outer layer of six silver ions which themselves are tetrahedrally coordinated by six bridging iodides and capped by the six PBn3 ligands. The top of the onion features a silver ion with three iodo ligands arranged in a near-planar trigonal arrangement around it. Single crystal X-ray crystallography shows the complexes 2 and 3 to contain columns of discrete [Ag(PBn3)2]+ cations with a linear P–Ag–P coordination, as also observed in the simple salts, 4 and 5, where the anion is [PF6]− and [BF4]−. The phenyl groups of PBn3 swing back over the silver to generate a sixfold phenyl embrace. However, in 3, although the PBn3 sites are fully occupied, about a quarter of the sixfold phenyl embraces are devoid of the object of their attention, the encapsulated silver ion. For 2, the [AgCl3]2− anions are trigonal-planar, three-coordinated. For 3, the appear as motifs in an approximately 25% silver-deficient Ag4 cluster. The crystal structures of the three-coordinate halides, 6 and 7, show that the geometry around the silver is close to a T-shape, with the chloride and iodide ions bound. The far-IR and 31P CP MAS NMR spectra of a selection of the new complexes confirm aspects of their symmetry as deduced from the crystallographic studies. [Copyright &y& Elsevier]

polymeric silver(I) complex, bis( N-methylthiourea)silver(I) nitrate, {[Ag(Metu)]NO} is prepared and its crystal structure is determined. The compound crystallizes in the monoclinic C2/ c space group. In the structure, distorted AgS tetrahedra are linked through the sulfur atoms of the Metu ligand to form isolated infinite chains of the type [Ag(SR)]. The cationic chains are separated from each other by nitrate ions that do not coordinate to the metal ion. The chains are bridged via N-H...O hydrogen bonds involving the nitrate ions. The complex exhibits an Ag-Ag separation of ∼3.21 Å indicating the existence of significant argentophilic interactions. An upfield shift in the >C=S resonance of Metu in C NMR and downfield shift in the N-H resonance in H NMR are consistent with sulfur coordination to silver(I). [ABSTRACT FROM AUTHOR]