Anion dependent silver(i) complexes of pyrazine mono-N-oxide

Pyrazine mono-N-oxide reacts with silver salts to form either discrete complexes involving monodentate N-coordination or 1D coordination polymers in which the ligand acts in a N,O-bridging bidentate coordination mode.

Effect of anion on Ag(i)meso-helical chains formed with 4,4′-dipyridyl ketone: solventversusanion bridging and anion effects on the strength of ligand binding

Related coordination polymers with varying Ag : L ratios produced a series (1 : 1) that was not sensitive to anion and another (1 : 2) that displayed sensitivity to the anion showing a transition from 1D chains to 2D nets.

Diverse silver(i) sulfobenzoate coordination polymers and their recycling property as homogeneous catalyst in oxygenation of sulfide

Four silver sulfobenzoate coordination polymers with bpmb ligands were prepared. The variable positions of sulfonate groups on benzene rings gave rise to different coordination polymers and variable chemical properties.

Pyridine N-oxide: a hyperdentate argentophile

Pyridine N-oxide reacts with silver(i) perchlorate monohydrate in three different stoichiometric ratios to produce three very different 1-D coordination polymers.

Synthesis, characterization, crystal structures and thermal and photoluminescence studies of dimethylpyrazine-carboxylate mixed ligand silver(i) coordination polymers with various multinuclear silver units

Seven new silver(i) coordination compounds based on dimethylpyrazine have been synthesized and characterized.

Discrete and polymeric, mono- and dinuclear silver complexes of a macrocyclic tetraoxime ligand with AgI-AgI interactions

Macrocyclic compounds that can bind cationic species efficiently and selectively with their cyclic cavities have great potential as excellent chemosensors for metal ions. Recently, we have developed a tetraoxime-type tetraazamacrocyclic ligand 1 formed through a facile one-pot cyclization reaction. Aiming to explore and bring out the potential of the tetraoxime macrocycle 1 as a chelating sensor, we report herein the preparation of several kinds of silver complexes of 1 and their unique coordination structures determined by single-crystal X-ray diffraction analyses. As a result, the formation of two kinds of discrete structures, monomeric complexes [Ag(1)X] (X = counter anions) and a dimeric complex [Ag₂(1)₂]X₂, and two kinds of polymeric structures from a mononuclear complex, [Ag(1)]_nX_n, and from a dinuclear complex, [Ag₂(1)X₂]_n, was demonstrated. In the resulting complexes, the structurally flexible macrocyclic ligand 1 was found to provide several different coordination modes. Notably, in some silver complexes of 1, Ag^I–Ag^I interactions were observed with different Ag^I–Ag^I distances which depend on the kind of counter anions and the chemical composition.

Modeling the effect of H-bonding interactions and molecular packing on the molecular structure of [Ag(ethylnicotinate)(2)]NO (3) complex

The gas phase molecular structure of a single isolated molecule of [Ag(Etnic)(2)NO(3)];1 where Etnic = Ethylnicotinate was calculated using B3LYP method. The H-bonding interaction between 1 with one (complex 2) and two (complex 3) water molecules together with the dimeric formula [Ag(Etnic)(2)NO(3)](2);4 and the tetrameric formula [Ag(Etnic)(2)NO(3)](4);5 were calculated using the same level of theory to model the effect of intermolecular interactions and molecular packing on the molecular structure of the titled complex. The H-bond dissociation energies of complexes 2 and 3 were calculated to be in the range of 12.220-14.253 and 30.106-31.055 kcal mol(-1), respectively, indicating the formation of relatively strong H-bonds between 1 and water molecules. The calculations predict bidentate nitrate ligand in the case of 1 and 2, leading to distorted tetrahedral geometry around the silver ion with longer Ag-O distances in case of 2 compared to 1, while 3 has a unidentate nitrate ligand leading to a distorted trigonal planar geometry. The packing of two [Ag(Etnic)(2)NO(3)] complex units; 4 does not affect the molecular geometry around Ag(I) ion compared to 1. In the case of 5, the two asymmetric units of the formula [Ag(Etnic)(2)NO(3)] differ in the bonding mode of the nitrate group, where the geometry around the silver ion is distorted tetrahedral in one unit and trigonal planar in the other. The calculations predicted almost no change in the charge densities at the different atomic sites except at the sites involved in the C-H⋯O interactions as well as at the coordinated nitrogen of the pyridine ring.

Antibacterial action of 4,4'-bipyrazolyl-based silver(I) coordination polymers embedded in PE disks

Coupling the rigid spacer 4,4'-bipyrazole (H(2)BPZ), in its anionic or neutral form, to different silver(I) salts allowed isolation of the novel coordination polymers [Ag(2)(BPZ)] (1) and [Ag(H(2)BPZ)(X)] (X = NO(3), 2; ClO(4), 3; BF(4), 4; PF(6), 5; CH(3)SO(3), 6; CF(3)SO(3), 7), which were fully characterized by infrared and emission spectroscopies, thermal analysis, and X-ray powder diffraction. The crystal structure of 1 consists of 2-D layers containing 1-D chains of Ag(I) ions bridged by exo-tetradentate bipyrazolato moieties. The crystal structures of the [Ag(H(2)BPZ)(X)] species 2-7 feature 1-D chains of [Ag(H(2)BPZ)] stoichiometry, along which the metal centers are bridged by exo-bidentate bipyrazolyl spacers. Contacts among adjacent chains are mediated by the counterions through nonbonding interactions involving the Ag(I) ions and the pyrazolyl N-H groups. Thermogravimetric analyses disclosed the good thermal stability of these materials, decomposing in the range 200-300 °C. Under UV irradiation at room temperature, all the species showed a yellow-green emission centered in the range 520-522 nm. When embedded into polyethylene disks, 1, 2, and 4-7 demonstrated their activity as topical antibacterial agents against suspensions of E. coli, P. aeruginosa, and S. aureus: complete reduction of the three bacterial strains was achieved in 24 h, reduction of S. aureus reaching ca. 90% in only 2 h. Biocidal action was expressed also by contact susceptibility tests.