Syntheses,crystal structures,and magnetic properties of two new manganese(II) complexes based on biphenyl-2,5,2′,5′-tetracarboxylic acid

Two new complexes, [Mn(H₂bptc)(2,2′-bpy)₂]?·?2H₂O (1) and [Mn₃(Hbptc)₂(2,2′-bpy)₃(H₂O)₈]?·?2H₂O (2) (H₄bptc?=?biphenyl-2,5,2′,5′-tetracarboxylic acid, 2,2′-bpy?=?2,2′-bipyridine), have been synthesized under hydrothermal conditions. Their structures have been characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra, powder X-ray diffraction, and thermogravimetric analyses. Complexes 1 and 2 are both linked into 3-D supramolecular networks by non-covalent interactions (O–H?···?O, C–H?···?O, C–H?···?π, and π?···?π). Complexes 1 and 2 exhibit weak antiferromagnetic interactions.     

Linear oxalato- and 4,4′-dipyridyldisulfide-bridged copper(II) coordination polymer involving in situ ligand synthesis

The reaction of 1,3-bis(pyridyl-4-ylthio)propan-2-one with Cu(ClO₄)₂?·?6H₂O gave a new complex {[Cu₂(4PDS)₂(ox)(H₂O)₄](ClO₄)₂} _n (4PDS?=?4,4′-dipyridyldisulfide, ox?=?oxalate), with 4PDS and ox being created by the Cu(II)-assisted oxidation of 1,3-bis(pyridyl-4-ylthio)propan-2-one. The complex determined by X-ray crystallography is a 1D polymer, in which metallacycles formed by two 4PDS and two Cu(II) ions are further bridged through ox anions. It crystallizes in the orthorhombic system, space group Fddd, with lattice parameters a?=?15.106(2), b?=?23.667(4), c?=?27.637(3)?Å and Z?=?8.     

Synthesis and crystal structure of a 2-D yttrium coordination network with propylenediamine-N,N,N′,N′-tetraacetic acid

A 2-D binuclear coordination polymer, {[Y^III(Hpdta)(H₂O)]_2?·?6H₂O} _n (H₄pdta?=?propylenediamine-N,N,N′,N′-tetraacetic acid), has been synthesized through direct hydrothermal reaction and characterized by infrared spectrum and thermal analysis. Single-crystal X-ray diffraction reveals that Y(III) is eight-coordinate of almost standard square antiprismatic polyhedron.     

Crystal structure of a hydroxo-bridged dimeric uranyl complex with a 2,2′:6′,2″-terpyridine ligand

A new dimeric compound [{UO₂(μ-OH)(terpy)}₂](ClO₄)₂·0.67CH₃CN, containing an uranyl cation and a tridentate 2,2′:6′,2″-terpyridine (terpy) ligand, is synthesized from an acetonitrile solution of uranyl perchlorate and terpy. The crystal structure of the compound is determined by single crystal X-ray diffraction. The crystal structure shows the formation of symmetric and asymmetric cationic hydroxo-bridged uranyl dimers. The uranium atoms adopt a distorted pentagonal bipyramidal configuration with a UO₄N₃ coordination environment formed by two uranyl O atoms, three N atoms from the terpy ligand, and two O atoms from the hydroxide anions.     

Three new zinc(II) complexes constructed by biphenyl-2,2′,6,6′-tetracarboxylic acid: Effect of solvents and terminal ligands

Interaction of biphenyl-2,2′,6,6′-tetracarboxylic acid (H₄bta) and Zn(II) ions in DMF led to the formation of a one-dimensional coordination polymer, while in the presence of 1,10-phenanthroline and 1H,1′H-2,2′-biimidazole as terminal ligands in H₂O, analogous interactions induced the generation of two-dimensional layers with (6, 3) topology. The bta ligands in these three coordination polymers adopt η⁴,μ₂-tetradentate, η⁵,μ₄-pentadentate and η⁴,μ₄-tetradentate coordination modes, respectively, and the corresponding angles of two benzene rings of bta ligands are 70.52, 83.81 and 73.35°, in accordance with the coordination modes and steric hindrance effect of the terminal ligands.     

Synthesis,crystal structure,and biological activity of 4′-chloro-2,2′ : 6′,2″-terpyridine (Cltpy) as tridentate ligand in a Cd(II) complex

A new Cd(II) complex with 4′-chloro-2,2′?:?6′,2″-terpyridine (Cltpy), [Cd(Cltpy)(NO₃)₂(H₂O)_0.45(CH₃OH)_0.55], has been synthesized and characterized by CHN elemental analysis, ¹H-NMR, ¹³C-NMR, IR spectroscopy, and structurally analyzed by X-ray single-crystal diffraction. The single-crystal X-ray analyses show that the coordination number is seven with three terpyridine (Cltpy) N-donors, three oxygen atoms of two nitrates and one oxygen atom of methoxy/water. The antibacterial activities of Cltpy and its Cd(II) complex are tested against different bacteria. The free ligand has considerable activity against Staphylococcus aureus, Bacillus anthracis, and Pseudomonas aeruginosa (inhibition zones?≥?20?mm), but has moderate activity against Escherichia coli and Streptococcus pyogenes (inhibition zones?≤?15?mm). In comparison with free Cltpy ligand, its complex has more activity against Klebsiella pneumonia, S. aureus, and B. anthracis (inhibition zones?≥?30?mm), but is inactive against P. aeruginosa and S. pyogenes. The quantitative assays gave minimal inhibitory concentration values in the range 6.25–100?mg?mL^?1 that confirmed the above results. Against K. pneumonia and S. aureus, antibacterial activity of the complex is higher than Cltpy ligand.     

3-D Coordination polymer containing a 1-D tunnel filled with 4,4′-bpy: synthesis,crystal structure,and characterization

A coordination polymer, [Co(2-mpac)₂(4,4′-bpy)·(4,4′-bpy)] _n (2-mpac: 5-methyl-2-pyrazinecarboxylic acid; 4,4′-bpy: 4,4′-bipyridine), has been synthesized through hydrothermal synthesis and structurally characterized by X-ray single crystal diffraction. Single crystal X-ray diffraction analysis reveals a 3-D network featuring a 1-D tunnel filled with 4,4′-bpy molecules. Elemental analysis, IR, thermogravimetric analysis, and magnetic properties are presented.     

Cadmium(II) complex with (1′H-[2,2′]biimidazoly-1-YL)-acetic acid: Synthesis, crystal structure, and luminescence

A new cadmium(II) complex with (1′H-[2,2′]Biimidazoly-1-yl)-acetic acid (HBDAC) [Cd(BDAC)₂(H₂O)₂]·H₂O is synthesized and structurally characterized, which crystallizes in the monoclinic system, space group P2₁/c, a = 8.465(3) Å, b = 14.164(5) Å, c = 11.294(3) Å, α = 90°, β = 127.405(17)°, γ = 90°, Z = 2. The [Cd(BDAC)₂(H₂O)₂]·H₂O units are further bridged by O-H…O, N-H…O, C-H…O hydrogen bonds, π-π stacking and C-O…π interactions, generating a three-dimensional supramolecular structure. In addition, luminescence measurements reveal that complex 1 exhibits strong fluorescent emission in the solid state at room temperature.     

Cadmium(II) complexes containing 2,2′-dimethyl-4,4′-bithiazole ligand: synthesis,characterization, and crystal structure

Mononuclear and coordination polymer compounds of 2,2′-dimethyl-4,4′-bithiazole (dm4bt) ligand have been prepared by metallation of dm4bt with Cd(NO₃)₂ · 4H₂O and CdCl₂ · H₂O. The compounds were characterized by IR, ¹H NMR, UV–Vis spectroscopy, and X-ray crystallography. The structural study of [Cd(dm4bt)₂(NO₃)₂] · H₂O (1) shows that the complex is a monomeric seven-coordinate (CdN₄O₃) cadmium(II)-bithiazole system with two bidentate dm4bt and mono and bidentate nitrates. The structure of [Cd(dm4bt)Cl₂] _n (2) is a distorted octahedral environment around the cadmium(II) (CdN₂Cl₄) forming a 1-D coordination polymer as a result of bridging by two chlorides and 2-D structure from π–π stacking interactions.     

Synthesis,characterization, and crystal structure of one zinc(II) complex with 4-Hydroxypyridine-2,6-Dicarboxylic acid and 4,4′-bipyridine

A new zinc(II) coordination polymer, {[Zn(HCAM)(4,4′-Bipy)_0.5] · H₂O} _n (I) (H₃CAM = 4-hydroxypyridine-2,6-dicarboxylic acid; 4,4′-Bipy = 4,4′-bipyridine), has been synthesized by hydrothermal reaction of Zn(OAc)₂, H₃CAM and 4,4′-Bipy. It has been structurally characterized by element analysis, IR-spectra. X-ray single-crystal analysis was carried out for I (CIF file CCDC no. 974199), which crystallizes in the orthorhombic system, space group Pbca. The single X-ray diffraction studies reveal that I shows a new 2D wave-like plane with 3-connected net. Furthermore, the thermal stability of compound I was studied.     

Synthesis of a C60 complex withN,N,N′,N′-tetramethyl-p-phenylenediamine and its crystal structure

The complex of fullerene C₆₀ withN,N,N,N-tetramethyl-p-phenylenediamine (TMPD) was synthesized and studied by X-ray analysis.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1285–1287, May, 1996. 1996     

A complex based on a decorated Keggin-type cluster from Cu(II) and 4,4′-dimethyl-2,2′-bipyridine: synthesis,structure and proton conductivity

A proton-conductive complex based on decorated Keggin-type cluster, {[Cu(dmbipy)(H₂O)₃]₂[SiW₁₂O₄₀]}·7H₂O (where dmbipy is 4,4′-dimethyl-2,2′-bipyridine) (1), was synthesized by reaction of CuSiW₁₂O₄₀·nH₂O and dmbipy at room temperature. The product was characterized by elemental analysis, infrared spectroscopy, and single-crystal X-ray diffraction analysis. Single-crystal X-ray diffraction analysis at 293 K revealed that 1 crystallized in the monoclinic space group C2/c and has a 3-D supramolecular network with 1-D hydrophilic channels constructed by a decorated Keggin-type cluster, [Cu(dmbipy)(H₂O)₃]₂SiW₁₂O₄₀, and solvent water molecules via hydrogen-bonding interactions. Thermogravimetric analysis suggests that 1 has high-thermal stability and good water binding in 1-D hydrophilic channels from 20 to 100 °C. Compound 1 exhibits good proton conductivities (over 10^?3 S cm^?1) at 100 °C in the relative humidity range 35–98%.     

Synthesis,structure, and DNA-binding studies of a dicopper(II) complex with N-phenolato-N′-[2-(dimethylamino) ethyl]oxamide as ligand

A new µ-oxamido-bridged dicopper(II) complex, [Cu₂(pdmaeox)(bpy)(H₂O)](pic)?·?H₂O [H₃pdmaeox?=?N-phenolato-N′-[2-(dimethylamino)ethyl]oxamide, Hpic?=?2,4,6-trinitrophenol, bpy?=?2,2′-bipyridine], has been synthesized and characterized by elemental analyses, molar conductivity measurement, infrared, and electronic spectra studies, and X-ray single-crystal diffraction. The complex crystallizes in the triclinic system, P 1 space group, with crystallographic data: a?=?10.7815(2)?Å, b?=?11.3598(2)?Å, c?=?14.1389(3)?Å, and z?=?2. In [Cu₂(pdmaeox)(bpy)(H₂O)]⁺, one copper(II) resides in the inner site with a square-planar coordination geometry and the other is chelated by the two exo-oxygen atoms of the cis-pdmaeox^3? ligand in a square-pyramidal environment. The Cu···Cu separation through cis-pdmaeox^3? bridge is 5.1834(4)?Å. The crystal structure is stabilized by hydrogen bonds and π–π stacking interactions. The interaction of the dicopper(II) complex with herring sperm-DNA (HS-DNA) has been investigated by electronic absorption titration, fluorescence titration, electrochemical titration, and viscosity measurements. The results reveal that the interaction of the dicopper(II) complex with HS-DNA might be electrostatic binding. The effects of bridging ligand on the interaction of the dinuclear complex with HS-DNA were preliminarily investigated.     

A 3-D Mn(II) complex containing N-isonicotinyl,N′,N′′-bis(hexamethylenyl) phosphoric triamide ligand: synthesis,structural characterization,and thermal studies

A new phosphoryl-containing ligand, N-isonicotinyl, N′,N′′-bis(hexamethylenyl) phosphoric triamide (1), was synthesized and characterized using IR, ¹H, ¹³C, and ³¹P NMR and UV–vis spectroscopy. Reaction of 1 with MnCl₂·4H₂O led to the formation of Mn(II) complex with the formula {Mn[4-NC₅H₄C(O)NHP(O)(NC₆H₁₂)₂]₂Cl₂}_n (2). Crystal structures of 1 and 2 were determined by X-ray crystallography, which reveals that 2 is centrosymmetric with two phosphoryl oxygens, chloride and nitrogen in trans positions. Coordination of bridged bidentate 1 through oxygen of the phosphoryl and nitrogen of the pyridine afforded a 3-D network extended by coordinative bonds. Compound 2 and its nano-sized particles prepared by sonochemical method were characterized by IR spectroscopy, X-ray powder diffraction, and thermal analysis and exhibited paramagnetic behavior at room temperature. Crystalline mixture of Mn₂P₂O₇ and Mn₂P₄O₁₂ was identified as a thermolysis product of 2.     

A novel copper(II) complex constructed with mixed ligands of biphenyl-4,4′-dicarboxylic acid (H2bpdc) and dipyrido[3,2-d:2′,3′-f]quinoxaline (Dpq): Synthesis,structure, electrochemistry and electrocatalysis

A novel metal–organic framework [Cu₂(bpdc)₂(Dpq)₂(H₂O)]·H₂O (1) has been obtained from hydrothermal reaction of copper chloride with the mixed ligands [biphenyl-4,4′-dicarboxylic acid (H₂bpdc) and dipyrido[3,2-d:2′,3′-f]quinoxaline (Dpq)], and structurally characterized by elemental analysis, IR, TG and single-crystal X-ray diffraction analysis. The unique feature is that there simultaneously exist two kinds of one-dimensional (1-D) zigzag polymeric chains in complex 1. Moreover, the 1-D polymeric chains are ultimately packed into a three-dimensional (3-D) supramolecular framework through two different hydrogen bonding interactions. The adjacent different chains are linked by C–H?O hydrogen bonding interactions, and the same kind chains are further connected through C–H?π stacking interactions. Additionally, the complex 1 was used as solid bulk-modifier to fabricate renewable carbon paste electrode (Cu-CPE) by the direct mixing method. The electrochemical behavior and electrocatalysis of Cu-CPE have been studied in detail. The results indicate that Cu-CPE give one-electron quasi-reversible redox waves in potential range of 400 to ?300 mV due to the metal copper ion Cu(II)/Cu(I). The Cu-CPE showed good electrocatalytic activity toward the reduction of the bromate, nitrite and hydrogen peroxide. The electrocatalytic reduction peak currents of KBrO₃, KNO₂ and H₂O₂ showed a linear dependence on their concentrations. All of the results revealed that the Cu-CPE had a good reproducibility, remarkable long-term stability and especially good surface renewability by simple mechanical polishing in the event of surface fouling, which is important for practical application.     

Synthesis,crystal structure and antibacterial activity of a new binuclear copper(II) complex with N,N ′- bis ( N -hydroxyethylaminopropyl)oxamido as a bridging ligand

A new μ-oxamido-bridged dicopper(II) complex, [Cu₂(heap)](ClO₄)₂?·?2H₂O [H₂heap?=?N,N′-bis(N- hydroxyethylaminopropyl)oxamido], has been synthesized and structurally characterized by elemental analyses, molar conductance, IR and single-crystal X-ray diffraction. The single crystal X-ray analysis reveals that the asymmetric unit of the complex is composed of half a binuclear cation [Cu₂(heap)]²⁺, one perchlorate anion, and one lattice water molecule. Each copper(II) atom is tetracoordinate in a distorted square-planar geometry and the bridging ligand (H₂heap) adopts the trans conformation with an inversion centre at the middle of the C2–C2ⁱ bond. The structure cohesion is ensured by hydrogen bonding interactions, which form a two-dimensional supramolecular framework. The antibacterial assay indicates that the complex showed better activity than the ligand.     

A copper(II) complex with 2-(2′-pyridyl)benzimidazole and l-arginine: synthesis,structure, antibacterial activities,and DNA interaction

A Cu(II) complex with 2-(2′-pyridyl)benzimidazole and l-arginine has been synthesized and investigated by elemental analysis, molar conductivity, IR, UV/vis, and X-ray diffraction. The complex crystallizes in the triclinic space group P1 with six molecules in a unit cell of dimensions a?=?10.6397(5)?Å, b?=?19.2178(8)?Å, c?=?20.0387(9)?Å, α?=?75.3670(10)°, β?=?79.4670(10)°, γ?=?87.4470(10)°, V?=?3897.6(3)?ų, R ₁?=?0.0408, and wR ₂?=?0.0502. The complex contains six crystallographically independent complexes, Cu1, Cu2, Cu3, Cu4, Cu5, and Cu6, which have a distorted square-pyramidal geometry. The complex was screened for its in vitro antibacterial activities against two Gram-positive (Bacillus subtilis and Staphylococcus aureus) and two Gram-negative (Escherichia coli and Salmonella) micro-organisms. The complex exhibited good antibacterial activities against the micro-organisms compared with HPB and Cu(ClO₄)₂. Interaction of the complex with DNA was studied by electronic absorption spectroscopy, fluorescence spectroscopy, circular dichroic spectroscopy, viscosity measurements, and agarose gel electrophoresis. Results suggest that the complex could bind to CT-DNA via partial intercalation, and cleave the plasmid DNA with involvement of hydroxyl radicals, and probably singlet oxygen-like copper-oxo species in the presence of ascorbate.     

Synthesis,crystal structure,and luminescence of a new zinc(II) coordination polymer based on 2-naphthol-5-carboxylate and 4,4′-bipyridine

To further explore the coordination possibilities of naphthalene-based carboxylic acids, a Zn^II coordination polymer, [Zn₃(L)₆(bipy)₂] _n (1), with bulky 2-naphthol-5-carboxylate (L) and bridging 4,4′-bipyridine (bipy), was synthesized and characterized. Structural analysis reveals that 1 is a 1-D polymeric chain with trinuclear units as nodes, which are further extended via interchain secondary interactions, such as O–H ··· O hydrogen-bonding and aromatic π ··· π stacking interactions, to form an overall 3-D framework. Complex 1 exhibits strong solid-state luminescence emission at room temperature, mainly originating from intraligand π→π* transition of L.     

Synthesis, crystal structure, and luminescence properties of the tetranuclear complex of cadmium(II) acetate with 4,4′-(1,4-phenylenediisopropylidene)bis-aniline

The complex compound [CdL_1.25(CH₃CO₂)₂(H₂O)], where L = NH₂-C₆H₄-C(CH₃)₂-C₆H₄-C(CH₃)₂-C₆H₄-NH₂ was synthesized and its crystal structure was determined. The crystals are triclinic, space group P $ \bar 1 $ , a = 10.160(1) ?,b = 17.442(1) ?, c = 20.232(1) ?, ?? = 67.93(1)°, ?? = 87.22(1)°, ?? = 77.65(1)°, V = 3340.2(4) ?³, ??_calc = 1.392 g/cm³, Z = 4. The structure contains two crystallographically non-equivalent Cd²⁺ ions, each coordinating two nitrogen atoms of two ligands L, four oxygen atoms of two bidentate acetate groups, and one water molecule. The coordination polyhedron of Cd²⁺ ions is anirregular sevenvertex polyhedron. The interaction of cadmium with ligands L gives rise to centrosymmetric tetranuclear complexes [Cd₄L₅].     

Synthesis,structure, photophysical properties and biological activity of a cobalt(II) coordination complex with 4,4′-bipyridine and porphyrin chelating ligands

A new bioactive material of cobalt(II) with 5,10,15,20-tetrakis[4 (benzoyloxy)phenyl] porphyrin (TPBP) and bpy ligands ([Co^II(TPBP)(bpy)₂] 1) has been synthesized and characterized by Single-crystal X-ray diffraction (SCXRD), spectroscopic methods and quantum-chemistry calculations. In the crystalline structures of six coordinated Co(II) [Co^II(TPBP)(bpy)₂] 1, linear 1D polymeric chains were observed in which all the porphyrin units are aligned parallel to each other. The crystal packing is stabilized by inter-and intramolecular C–H⋯O and C–H⋯N hydrogen bonds, and by weak C–H⋯Cg π interactions. Interestingly, NBO–Second-order perturbation theory analysis, carried out at the UB3LYP/6-31G(d)/SDD DFT level of theory, demonstrated that a two-center bond between the nitrogen atoms and the cobalt ions (Co) was not found, the Co–N_py/bp interactions are coming from an electronic delocalization between the N_py/N_bp filled orbitals to the anti-bonding LP*(4) and LP*(5) metal NBOs. Mass spectroscopy, and elemental analysis were also investigated to confirm the molecular structure. The downfield shift and the peak broadening of the axial ligand resonances observed in the ¹H NMR indicated the contiguity to the paramagnetic Co(II) center. Additionally, the photophysical properties have been evaluated by UV–visible absorption, and fluorescence emission spectroscopies. Finally, bioactivity investigations revealed that free porphyrin TPBP, Co^IITPBP and complex 1 could be used as potential antioxidant agents.