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The electron paramagnetic resonance (EPR) parameters (g factors and hyperfine structure constants) for Cu²⁺ in [Cu(ipt)(dap)H₂O] _n × n H₂O (ipt is isophthalic acid, dap - 1,3-diaminopropane) are theoretically investigated from the high order perturbation formulas of these parameters for a 3 d ⁹ ion in a rhombically elongated octahedron. The ligand orbital and spin-orbit coupling contributions are included from the cluster approach because of strong covalency of the system. The nearly axial anisotropies of the g factors and hyperfine structure constants are correlated to the significant elongation distortion of the five-fold coordinated Cu²⁺ (in a distorted square pyramidal [CuN₂O₃] group). Nevertheless, the perpendicular anisotropies arising from the nonequivalent planar ligands are largely concealed by the experimental uncertainties. The theoretical analysis of the EPR behaviours for [Cu(ipt)(dap)H₂O] _n × n H₂O would be helpful to understand the local structures and properties of this and relevant systems.

[Ni(5,5'-dmbipy)₂Cl₂]×3H₂O (1) complex was obtained from the reaction of NiCl₂×6H₂O with 5,5'-dimethyl-2,2'-bipyridine (5,5'-dmbipy) in a mixture of CH₃OH/CH₃CN. This complex was characterized by elemental analysis, IR, UV-Vis and luminescence spectroscopy, and its structure was determined by the single-crystal diffraction method. The Ni atom has a distorted octahedral coordination by four N atoms from two 5,5'-dmbipy ligands and two Cl^- anions.

The crystal structures of the compounds with the composition [Rh(H₂O)₅Cl](C₇H₇O₃S)₂ (I) and Cs[Rh(H₂O)₅NO₃](C₇H₇O₃S)₃×H₂O (II) are determined. Crystallographic data for I: a = 10.063(10) Å, b = 7.771(8) Å, c = 13.524(15) Å; b = 100.44(3)°, space group P 2₁, Z = 2, d _calc = 1.823 g/cm³; for II: a = 16.221(3) Å, b = 9.646(19) Å, c = 21.307(4) Å, b = 92.06(3)°, space group P 2₁, Z = 8, d _calc = 1.833 g/cm³. The compounds are characterized by IR spectroscopy and powder X-ray diffraction. The rhodium atoms have a distorted octahedral environment consisting of five oxygen atoms of coordinated water molecules and one chloride ion (I)/oxygen atom of the nitrate ion (II) with the following distances: Rh-O_H2O of 1.993-2.075 Å and Rh-Cl of 2.270 Å for I; Rh-O_H2O of 1.996-2.031 Å and Rh-O_NO3 of 1.990 Å for II.

A novel ladder-like polymeric silver(I) complex, [Ag₂L₂] _n ×2 n H₂O, where L is 3-aminopyrazine-2-carboxylate, was obtained by the reaction of 3-aminopyrazine-2-carboxylic acid and silver oxide in aqueous ammonia. The complex was characterized by elemental analysis, IR spectra and single crystal X-ray determination. The smallest repeat unit contains a [Ag₂L₂] moiety and two water molecules. The Ag⋯Ag distance is 3.176(1) mmol. Each Ag atom is in a Y-shaped coordination, with one carboxylate O and two pyrazine N atoms from two ligands. In the crystal structure of the complex, the dinuclear silver moieties are linked through 3-aminopyrazine-2-carboxylate ligands, to form 1D ladder-like chain along the b axis. The water molecules are linked to the silver chain through hydrogen bonds. There are p⋯p interactions between the chains. The complex showed effective cytotoxic property on human lung cancer cell line A549.

Coordination of a pyridine-based bridging ligand, 4-bpmp, with cadmium nitrate afforded an infinite ladder-type complex {[Cd(4-bpmp)₂(H₂O)Cl₂]} _n (A) (4-bpmp = 1,4-bis(4-pyridylmethyl)piperazine) containing T -shaped building blocks. IR spectra, elemental analysis, and X-ray single-crystal diffraction were carried out to determine the composition and crystal structure of complex A. Inclined interpenetration of infinite ladders was observed in the solid structure. The combined work demonstrates the ability of bipyridyl coordination polymer leads to a novel metal complex with impressive structural motif.

For the first time, the fluoridotantalates(V) with the mono- and diprotonated 4-amino-1,2,4-triazolium cation of the heterocyclic base (C₂H₅N₄)₂TaF₇ and (C₂H₆N₄)TaF₇×H₂O, are synthesized and their crystal structures are determined. The orthorhombic crystals of (C₂H₅N₄)₂TaF₇ (space group Cmc 2₁) are formed of complex [TaF₇]^2- anions with the configuration of monocap trigonal prism and the monoprotonated (C₂H₅N₄)⁺ cations, one of which is statistically disordered. The crystal structure of (C₂H₆N₄)TaF₇×H₂O (space group Pna 2₁) consists of the pentagonal bipyramidal complex [TaF₇]^2- anions, the diprotonated (C₂H₆N₄)²⁺ cations, and the molecules of crystallization H₂O. In the structure of I, the (C₂H₅N₄)⁺ cations simultaneously exist as cis- and trans- conformers. The formation of the diprotonated 4-amino-1,2,4-triazolium cation (C₂H₆N₄)²⁺ was revealed for the first time. Via ionic interactions and N-H⋯F, N-H⋯N, and O-H⋯F hydrogen bonds, the units in I and II are arranged in a three-dimensional structure.

Acyclic tetraazametal gold(III) perrhenate complex [Au(C₉H₁₉N₄)](ReO₄)₂ is synthesized. The 3D crystal structure of the complex is stabilized by weak secondary interactions (N-H…O, C-H…O, С-H…Au hydrogen bonds, and Au…O contacts). The translation sublattice method shows that the motif of the mutual arrangement of cations can be considered to be pseudohexagonal. The product of the thermal decomposition of [Au(C₉H₁₉N₄)](ReO₄)₂ in a hydrogen atmosphere is a mixture of nanocrystalline phases (HCP phases based on Re and Au) with the coherent scattering region of 24 nm and 34 nm, respectively.

In this study, a novel phthalonitrile, 4-chloro-5-(2-((2-hydroxyethyl)( p -tolyl)amino)ethoxy)phthalonitrile (3), and its metallophthalocyanine derivatives (4-6) are prepared by cyclotetramerization with appropriate metal salts in dimethylformamide. The newly prepared compounds have been characterized by several spectroscopic techniques. All compounds are evaluated for their antioxidant and antibacterial potential. For the antioxidant studies, three tests are applied; DPPH (2,2-diphenyl-1-picrylhydrazylradical) scavenging, metal chelating and reducing power activity. Compound 4 exhibits the best DPPH scavenging activity as 35.2 % at 100 mg/L concentration. The metal chelating activities of compounds 3 and 4 are 69.7 % and 56.4 %, respectively. Reducing power activities of compounds 3 and 4 are higher than a-tocopherol which is used as positive control. All compounds show moderate antibacterial activity when compared to the standard antibiotics, amikacin and tetracycline.

A new tetranuclear complex [Cu₄(L)₄] (1) (H₂L = N-(2-hydroxyethyl)-3-metoxysalicylaldimine) has been synthesized and characterized by crystal structure analysis and magnetic susceptibility. Single-crystal X-ray diffraction studies reveal that complex 1 contains three independent Cu₄O₄ open-cubane cores of 4+2 type (four short and two long Cu⋯Cu distances), where the copper(II) centers are linked by alkoxo-bridges. Each copper(II) ion have a distorted square-pyramidal geometry. Variable-temperature magnetic susceptibility measurements on the tetranuclear complex 1 in the range 2-300 K indicate dominant antiferromagnetic coupling ( J = -108.46) between copper(II) centers.

A silver(I) complex of arginine (arg), [Ag(arg)]NO₃×0.5H₂O (1) was prepared and characterized by elemental analysis, IR and NMR spectroscopy, and X-ray crystallography. The IR and NMR spectroscopic data confirmed the coordination of the ligand to silver(I). The structure of 1 shows that it is polymeric with each silver atom bound to the carboxyl O atom of one arginine ligand and to the amino N atom of another adopting a linear coordination environment. The two coordinate N-Ag-O units are repeated to form infinite chains. The molecular structure is stabilized by N-H…O and C-H…O hydrogen bonds. Antimicrobial activities of the complex were evaluated by minimum inhibitory concentration against gram-negative bacteria ( E. coli , P. aeruginosa ), molds ( A. niger, P. citrinum ) and yeasts ( C. albicans, S. cerevisiae ).