Uncoordinated Water Mol-ecules Research Articles

Complexation of different transition metals with 4,4′-dimethyl-2,2′-bipyridine: Crystal structure, UV spectra and Hirshfeld surfaces

Four new complexes, [Co(dmbpy)2(dca)2]·CH3OH (1), [Ni(dmbpy)2(dca)2]·CH3OH (2), [Zn(dmbpy)2(dca)2]·(3) and [Cu(dmbpy)2(OH)2]·5H2O (4) (dca=dicyanamide), derived from 4,4′-dimethyl-2,2′-bipyridine (dmbpy) have been synthesized and characterized by elemental analysis, TGA and single-crystal X-ray diffraction. Crystal structures and Hirshfeld surfaces analysis revealed that the complexes 1–3 were mainly supported by OH⋯N, CH⋯N and π⋯π intermolecular interactions, and for complex 4, the uncoordinated water molecules play a key role in the construction of the 3D stacking motif. UV spectrum measurements demonstrate that all of the complexes show typical metal to ligand charge transfer (MLCT) absorption bands between 301 and 306nm. Moreover, after complexation, the absorption maximum bands about intraligand π→π* transitions similarly show slightly red shift compared to dmbpy ligand, consisting with the DFT calculations.

Layered vanadyl (IV) nitroprusside: Magnetic interaction through a network of hydrogen bonds

The hydrogen bond and π-π stacking are two non-covalent interactions able to support cooperative magnetic ordering between paramagnetic centers. This contribution reports the crystal structure and related magnetic properties for VO[Fe(CN)5NO]·2H2O, which has a layered structure. This solid crystallizes with an orthorhombic unit cell, in the Pna21 space group, with cell parameters a=14.1804(2), b=10.4935(1), c=7.1722(8) Å and four molecules per unit cell (Z=4). Its crystal structure was solved and refined from powder X-ray diffraction data. Neighboring layers remain linked through a network of hydrogen bonds involving a water molecule coordinated to the axial position for the V atom and the unbridged axial NO and CN ligands. An uncoordinated water molecule is found forming a triple bridge between these last two ligands and the coordinated water molecule. The magnetic measurements, recorded down to 2K, shows a ferromagnetic interaction between V atoms located at neighboring layers, with a Curie-Weiss constant of 3.14K. Such ferromagnetic behavior was interpreted as resulting from a superexchange interaction through the network of strong OH····OH2O, OH····NCN, and OH····ONO hydrogen bonds that connects neighboring layers. The interaction within the layer must be of antiferromagnetic nature and it was detected close to 2K.

Synthesis, structure and characterization of five new organically templated metal sulfates with 2-aminopyridinium.

The chemistry of organically templated metal sulfates has attracted interest from the materials science community and the development of synthetic strategies for the preparation of organic-inorganic hybrid materials with novel structures and special properties is of current interest. Sulfur-oxygen-metal linkages provide the possibility of using sulfate tetrahedra as building units to form new solid-state materials. A series of novel organically templated metal sulfates of 2-aminopyridinium (2ap) with aluminium(III), cobalt(II), magnesium(II), nickel(II) and zinc(II) were obtained from the respective aqueous solutions and studied by single-crystal X-ray diffraction. The compounds crystallize in centrosymmetric triclinic unit cells in three structure types: type 1 for 2-aminopyridinium hexaaquaaluminium(III) bis(sulfate) tetrahydrate, (C5H7N2)[Al(H2O)6](SO4)2·4H2O, (I); type 2 for bis(2-aminopyridinium) tris[hexaaquacobalt(II)] tetrakis(sulfate) dihydrate, (C5H7N2)2[Co(H2O)6]3(SO4)4·2H2O, (II), and bis(2-aminopyridinium) tris[hexaaquamagnesium(II)] tetrakis(sulfate) dihydrate, (C5H7N2)2[Mg(H2O)6]3(SO4)4·2H2O, (III); and type 3 for bis(2-aminopyridinium) hexaaquanickel(II) bis(sulfate), (C5H7N2)2[Ni(H2O)6](SO4)2, (IV), and bis(2-aminopyridinium) hexaaquazinc(II) bis(sulfate), (C5H7N2)2[Zn(H2O)6](SO4)2, (V). The templating role of the 2ap cation in all of the reported crystalline substances is governed by the formation of characteristic charge-assisted hydrogen-bonded pairs with sulfate anions and the presence of π-π interactions between the cations. Additionally, both coordinated and uncoordinated water molecules are involved in hydrogen-bond formation. As a consequence, extensive three-dimensional hydrogen-bonding patterns are formed in the reported crystal structures.

Supramolecular hydrogen-bonding patterns in the organic-inorganic hybrid compound bis(4-amino-5-chloro-2,6-dimethylpyrimidinium) tetrathiocyanatozinc(II)-4-amino-5-chloro-2,6-dimethylpyrimidine-water (1/2/2).

Zinc thiocyanate complexes have been found to be biologically active compounds. Zinc is also an essential element for the normal function of most organisms and is the main constituent in a number of metalloenzyme proteins. Pyrimidine and aminopyrimidine derivatives are biologically very important as they are components of nucleic acids. Thiocyanate ions can bridge metal ions by employing both their N and S atoms for coordination. They can play an important role in assembling different coordination structures and yield an interesting variety of one-, two- and three-dimensional polymeric metal-thiocyanate supramolecular frameworks. The structure of a new zinc thiocyanate-aminopyrimidine organic-inorganic compound, (C6H9ClN3)2[Zn(NCS)4]·2C6H8ClN3·2H2O, is reported. The asymmetric unit consist of half a tetrathiocyanatozinc(II) dianion, an uncoordinated 4-amino-5-chloro-2,6-dimethylpyrimidinium cation, a 4-amino-5-chloro-2,6-dimethylpyrimidine molecule and a water molecule. The Zn(II) atom adopts a distorted tetrahedral coordination geometry and is coordinated by four N atoms from the thiocyanate anions. The Zn(II) atom is located on a special position (twofold axis of symmetry). The pyrimidinium cation and the pyrimidine molecule are not coordinated to the Zn(II) atom, but are hydrogen bonded to the uncoordinated water molecules and the metal-coordinated thiocyanate ligands. The pyrimidine molecules and pyrimidinium cations also form base-pair-like structures with an R2(2)(8) ring motif via N-H...N hydrogen bonds. The crystal structure is further stabilized by intermolecular N-H...O, O-H...S, N-H...S and O-H...N hydrogen bonds, by intramolecular N-H...Cl and C-H...Cl hydrogen bonds, and also by π-π stacking interactions.

The effect of ligand substituent on crystal packing: Structural and theoretical studies of two Ga(III) supramolecular compounds

A new Ga(III) supramolecular compound (4,4′-bipyH2)[Ga(hpydc)2]2·7H2O (2) (where H2hpydc = 4-hydroxy-pyridine-2,6-dicarboxylic acid and 4,4′-bipy = 4,4′-bipyridine) was synthesized using the proton transfer reaction. Compound 2 was structurally characterized using single crystal X-ray diffraction, and it was shown that its asymmetric unit consists of two independent anionic Ga(III) complexes, one fully protonated 4,4′-bipyridine and seven uncoordinated water molecules. In order to understand the effect of pyridine OH substituent on supramolecular interactions and crystal packing, compound 2 was compared with (bipyH2)[Ga(pydc)2]·(H2pydc)·4H2O (1) (where H2pydc = pyridine-2,6-dicarboxylic acid), that does not have an OH group on the pyridine ligand. The Density Functional Theory (DFT) and Natural Bond Orbital (NBO) calculations and also Atoms in Molecules (AIM) analysis were used to analyze the non-covalent interactions in both complexes. The calculation of non-covalent interactions' energy provides a useful means to investigate their effects in the crystal packing.

Synthesis, Crystal Structures, and Luminescent Properties of Mononuclear Cu(II)/Ni(II) Complexes Containing N-Donor Ligands

The two mononuclear complexes containing N-donor ligands [Cu(phen)2Cl]·(5-SIPH2)·3H2O (1) and [Ni(phen)3]·2(5-SIPH2)·2H2O (2) (5-SIP = 5-sulfoisophthalate anion, phen = 1,10-phenanthroline) were synthesized by the slow solvent evaporation method. For complex 1, the copper ion is five-coordinated, which is coordinated by the two 1,10-phenanthroline molecules and a chloride ion to form a [Cu(phen)2Cl]+ cation. The three uncoordinated water molecules connect the [Cu(phen)2Cl]+ cations and (5-SIPH2)– anions to form three-dimensional network structure through the hydrogen bonds. For complex 2, the nickel ion is six-coordinated, which coordinates with three 1,10-phenanthroline molecules to generate the [Co(phen)3]2+ cation. The two free water molecules connect the (5-SIPH2)– anions to form a three-dimensional network structure through the hydrogen bonds. In the two complexes, the (5-SIPH2)– anions only balance the charges. The complexes exhibit the luminescence properties with emission maximum at 420 and 442 nm at room temperature, respectively. CCDC: 1007213, 1; 1007214, 2.

Synthesis, Crystal Structure, and Luminescent Property of One-Dimensional Chain Coordination Polymer [Cu(1,6-nds)(py)4]n·2.5nH2O

The copper coordination polymer [Cu(1,6-nds)(py)4]n·2.5nH2O (1,6-nds = 1,6-naphthalenedisulfonate anion, py = pyridine) was synthesized in water by the reflux method. The characterization results of X-ray single crystal diffraction show that the coordination polymer has a one-dimensional chain structure, the two sulfonate groups of 1,6-naphthalenedisulfonate anion bridge with two copper ions by coordination bonds. The copper ion also coordinates with four pyridine molecules. The uncoordinated water molecules interconnect with each other, and also connect to the complex molecules via hydrogen bonds. The coordination polymer displays a strong fluorescence emission peak centered at 462 nm.

A two-dimensional cadmium(II) polymer based on nicotinic acid and thiocyanate ligands.

A cadmium-thiocyanate complex, poly[[bis(nicotinic acid-κN)di-μ-thiocyanato-κ(2)N:S;κ(2)S:N-cadmium(II)] monohydrate], {[Cd(NCS)2(C6H5NO2)2]·H2O}n, was synthesized by the reaction of nicotinic acid, cadmium nitrate tetrahydrate and potassium thiocyanide in aqueous solution. In the crystal structure, each Cd(II) cation is in a distorted octahedral coordination environment, coordinated by the N and S atoms of nicotinic acid and thiocyanate ligands. Neighbouring Cd(II) cations are linked together by thiocyanate bridges to form a two-dimensional network. Hydrogen-bond interactions between the uncoordinated solvent water molecules and the organic ligands result in the formation of the three-dimensional supramolecular network.

Synthesis, characterization and biological activities of metal(II) dipicolinate complexes derived from pyridine-2,6-dicarboxylic acid and 2-(piperazin-1-yl)ethanol

The new water-soluble and air stable compounds (H2ppz)[Co(dipic)2]·6H2O (1), (H2ppz)[Ni(dipic)2]·6H2O (2) and (H2ppz)[Zn(dipic)2]·6H2O (3) were prepared by the reaction of corresponding metal(II) acetates and a proton transfer salt, (H2ppz) (Hdipic)2, (4) of pyridine-2,6-dicarboxylic acid (H2dipic) and 2-(piperazin-1-yl)ethanol (ppz). The compounds 1–3 were characterized by elemental, IR, UV–vis. thermal analyses, magnetic measurement and single crystal X-ray diffraction studies. The molecular structures of the title compounds consist of one 1-(2-hydroxyethyl)piperazine-1,4-diium (H2ppz+2) cation, one bis(pyridine-2,6-dicarboxylate)metal(II) [M(dipic)2]2− anion, and six uncoordinated water molecules. In compounds 1–3 the metal ions coordinate to two oxygen and one nitrogen atoms of two pyridine-2,6-dicarboxylate molecules forming an octahedral environment. Antimicrobial activities against Gram (−) wild type (Escherichia coli and Pseudomonas aeruginosa), Gram (+) wild type (Staphylococcus aureus, Staphylococcus epidermidis, Bacillus cereus and Bacillus subtilis) and clinical isolate (Morganella morganii, Proteus vulgaris and Enterobacter aeruginosa) were also studied. The results were reported, discussed and compared with the corresponding starting materials ((H2ppz) (Hdipic)2 (4), H2dipic and ppz). MIC (Minimal Inhibition Concentration) values of the newly synthesized compounds were determined as 4000 μg/ml (except B. subtilis and clinical isolate E. aeruginosa, >4000 μg/ml).

Synthesis, Crystal structure and Characterization of a New Oxalate Chromium (III) Complex

A new hybrid salt (C5H9N2)[Cr(C2O4)2(H2O)2].3H2O, 3,5-dimethylpyrazole Cis diaquadioxalatochromate(III) trihydrate, has been prepared by slow evaporation at room temperature and characterized by single crystal X-ray diffraction, IR, UV–visible spectroscopies, PXRD and thermogravimetric analyses. Furthermore, the observed crystal morphology was compared to the simulated one using the Bravais-Friedel, Donnay-Harker model. The structure of the title compound consists of [Cr(C2O4)2(H2O)2] − mononuclear anions, 3,5-dimethylpyrazole cations and three uncoordinated water molecules. The Cr 3+ ion is six coordinated in a slightly distorted octahedral environment, by two O atoms from two water molecules and four O atoms of two oxalate anions acting as chelating ligands. The cohesion of the structure is established by intermolecular O–H...O, N–H...O hydrogen bonds which connect ionic entities and water molecules and also by π– π stacking interactions between the rings of 3,5-dimethylpyrazole cations. Hence, both coordinated and uncoordinated water molecules play an important role in the hydrogen-bonding system and stabilize the structure. Fragments of the molecular structure of the complex show clearly the intermolecular N–H...O and O–H...O hydrogen bonds between the cation, the complex anion and the lattice water molecules which contribute to the cohesion of the ionic structure, leading to a three dimensional network.

Novel lanthanide complexes constructed from 3, 4-dimethoxybenzoic acid: crystal structures, spectrum and thermochemical properties

Four novel lanthanide complexes [Ln(3,4-DMOBA)3(H2O)2]·H2O·C2H5OH (Ln=Sm(1), Tb(2), Dy(3), Ho(4); 3,4-DMOBA=3, 4-dimethoxybenzoate) have been hydrothermal synthesized and characterized. Structural analyses reveal that adjacent lanthanide ions are connected by 3,4-DMOBA ligands adopting bridging bidentate mode to generate one-dimensional (1-D) structure with the uncoordinated water and ethanol molecules. 1-D structures are linked by hydrogen bonds to form a three-dimensional (3-D) structure, which is rarely observed in lanthanide carboxylic acids complexes. Under the radiation of UV light, complex 2 exhibits the characteristic emission of Tb3+ ion (5D4→7F6-3). The thermal decomposition mechanism is investigated by TG-FTIR technology. IR spectra of the evolved gases show that the uncoordinated water and ethanol molecules lose in the first step. And then 3,4-DMOBA ligand is decomposed into H2O, CO2 and other gaseous molecules as well as the gaseous organic fragments.

Crystal structure, spectroscopic and magnetic properties of a new iron(III) complex

We report herein the synthesis and physicochemical characterization of a new mixed-ligand iron(III) complex of the formula (C5H6ClN2)[Fe(C2O4)2(H2O)2]∙2H2O. This compound is prepared by slow evaporation at room temperature and characterized by single crystal X-ray diffraction. It is characterized by IR and UV-VIS spectra and thermal analysis (TG and DTA). In this compound, the iron ion has a slightly distorted square bipyramidal environment, coordinated by two chelating oxalate ions and two water molecules. Structural cohesion is essentially established by π–π interactions between the rings of pyridine groups and intermolecular hydrogen bonds connecting the ionic entities and uncoordinated water molecules. Magnetic susceptibility measurements exhibit the paramagnetic behavior at high temperatures. However, at low temperatures, the magnetic data show the occurrence of weak antiferromagnetic intermolecular interactions between the local spins.

Synthesis, X-ray structural and thermal analysis of a novel copper compound containing dissymmetric independent 5- and 6-coordinate CuL(H2O)n (n = 2, 3) units and hydrogen bond bridges.

The synthesis, thermogravimetric and X-ray structure analysis of a highly unusual copper compound prepared from a chiral tridentate Schiff base ligand is reported. The title compound [CuL(H(2)O(2)]. CuL(H(2)O(3)].H(2)O crystallizes in the orthorhombic crystal system in space group P2(1)2(1)2(1) with Z = 4. Two independent CuL(H(2)O)(n) complexes are present in the same unit cell, one five- and the other six- coordinate. The five-coordinate copper(II) centre occupies a distorted square-pyramidal geometry whereas the six-coordinate copper(II) centre has a distorted octahedral geometry. The independent copper complexes and the uncoordinated water molecule are joined together with intermolecular hydrogen bonds in a two-dimensional supramolecular network which lies parallel to the ab plane.

Large Tripodal Spacer Ligands for the Construction of Microporous Metal-Organic Frameworks with Diverse Structures and Photocatalytic Activities.

Two microporous complexes, [Zn(TATAB)(OCH3 )]⋅2 H3 O+ (1; TATAB=4,4',4''-[(1,3,5-triazine-2,4,6-triyl)tris(azanediyl)]tribenzoic acid), [Cu1.5 (μ2 -O)TATAB*] (2; TATAB*=4,4'-{[6-(dimethylamino)-1,3,5-triazine-2,4-diyl]bis(azanediyl)}dibenzoic acid) have been synthesized and characterized by elemental analysis, IR spectroscopy, UV absorption spectroscopy, and thermogravimetric analysis, and by powder XRD and single-crystal XRD analysis. Structural analyses revealed that complex 1 possesses a 3D porous framework with uncoordinated water molecules trapped in the pores; the dimensions of the channels are approximately 29.2×12.3 Å2 . Complex 2 has a 3D microporous network structure. In addition, the surface photovoltage and photocatalytic activities were also studied. The photocatalytic properties of the two complexes were investigated by the decomposition of methylene blue under UV and visible-light irradiation. The results revealed that 2 possessea a higher photocatalytic activity than 1 under UV or visible-light irradiation. The potential semiconductor and dye degradation properties of complexes 1 and 2 may be widely applied in the fields of chemical semiconductors and environmental protection in the future.

The Zinc(II) Coordination Polymer with Mixed-Ligand of 4-Hydroxypyridine-2,6-dicarbolic Acid and Benzene-1,2,4,5-tetracarboxylic Acid in the Presence of Piperazine as a Counter Ion: Synthesis, Crystal Structure and Solution Study

Mixed-ligand zinc(II) complex, {(pipzH2)[Zn(hypydc)(btc)0.5]·H2O} n , (1) was prepared with 4-hydroxypyridine-2,6-dicarboxylic acid (hypydcH2), benzene-1,2,4,5-tetracarboxylic acid (btcH4) and piperazine (pipz). This compound is composed of an anionic complex, [Zn(hypydc)(btc)0.5]2−, protonated piperazine as a counter-ion, (pipzH2)2+ and one uncoordinated water molecule. The three donor atoms of the (hypydc)2− and two donor atoms of bridged (btc)4− ligands form a distorted square pyramid arrangement around the ZnII center. In the crystal structure of the title compound, a wide range of non-covalent interactions consisting of hydrogen bonding (of the types of O–H···O, N–H···O and C–H···O with D···A ranging from 2.630(2) to 3.347(3) A, ion pairing and C–O···π stacking interactions connect the various components into a supramolecular structure. The quaternary complex system including of hypydcH2–btcH4–pipz and Zn2+ ion, has been investigated. The stoichiometry and stability constants of binary complexes including each of ligands (hypydcH2, btcH4, pipz) in presence of Zn2+ ion, ternary complexes including each two of three ligands (hypydcH2–btcH4, hypydcH2–pipz, btcH4–pipz) in presence of metal ion and finally quaternary systems including three ligands (hypydcH2–btcH4–pipz) and Zn2+ ion were calculated in aqueous solutions by potentiometric pH titration method. A novel polymeric mixed-ligand zinc(II) complex, {(pipzH2)[Zn(hypydc)(btc)0.5]·H2O} n containing 4-hydroxypyridine-2,6-dicarboxylic acid, benzene-1,2,4,5-tetracarboxylic acid and piperazine was synthesized and characterized.

Hexaaquamanganese(II) bis[hydrotris(3-methyl-2-thioxo-1-imidazolyl) borate] Tetrahydrate: A Non-coordinating Borate Ligand with Manganese(II) Metal Ion

The metallation of a tripodal ligand, hydrotris(3-methyl-2-thioxo-1-imidazolyl)borate with manganese(II) salt gave an unusual title compound, [Mn(H2O)6](C12H16N6BS3)2.4H2O. The presence of soft donor atom in the borate moiety may be the cause of non-coordinating interaction with metal ion. The manganese(II) ion is coordinated with six water molecules leads to distorted octahedral geometry. In the crystal, the cations, anions and uncoordinated water molecules are linked by intermolecular O‒H···O hydrogen bonds and week intermolecular O‒H···S and C‒H···S interaction, generating a three-dimensional network. The thermal behavior of the title compound was also investigated.

A three-dimensional coordination polymer based on the Zn₄(μ₃-OH)₂ unit: poly[[(μ₄-benzene-1,4-dicarboxylato)bis(μ₃-benzene-1,4-dicarboxylato)bis(μ₃-hydroxido)bis(1,10-phenanthroline-5,6-dione)tetrazinc] dihydrate

The title compound, {[Zn4(C8H4O4)3(OH)2(C12H6N2O2)2]·2H2O}n, has been prepared hydrothermally by the reaction of Zn(NO3)2·6H2O with benzene-1,4-dicarboxylic acid (H2bdc) and 1,10-phenanthroline-5,6-dione (pdon) in H2O. In the crystal structure, a tetranuclear Zn4(OH)2 fragment is located on a crystallographic inversion centre which relates two subunits, each containing a [ZnN2O4] octahedron and a [ZnO4] tetrahedron bridged by a μ3-OH group. The pdon ligand chelates to zinc through its two N atoms to form part of the [ZnN2O4] octahedron. The two crystallographically independent bdc(2-) ligands are fully deprotonated and adopt μ3-κO:κO':κO'' and μ4-κO:κO':κO'':κO''' coordination modes, bridging three or four Zn(II) cations, respectively, from two Zn4(OH)2 units. The Zn4(OH)2 fragment connects six neighbouring tetranuclear units through four μ3-bdc(2-) and two μ4-bdc(2-) ligands, forming a three-dimensional framework with uninodal 6-connected α-Po topology, in which the tetranuclear Zn4(OH)2 units are considered as 6-connected nodes and the bdc(2-) ligands act as linkers. The uncoordinated water molecules are located on opposite sides of the Zn4(OH)2 unit and are connected to it through hydrogen-bonding interactions involving hydroxide and carboxylate groups. The structure is further stabilized by extensive π-π interactions between the pdon and μ4-bdc(2-) ligands.

3D Microporous Lanthanide–Organic Frameworks Constructed from Left‐ and Right‐Handed Helical Chains: Synthesis, Crystal Structure, and Tunable Photo­luminescence

AbstractNew lanthanide–organic frameworks, [Ln2(2,6‐NDS)3(IP)(H2O)4]·H2O {Ln = Sm (1), Eu (2), Tb (3); 2,6‐NDS = 2,6‐Anaphthalenedisulfonate, IP = 1H‐imidazo[4,5‐f][1,10]‐phenanthroline}, were synthesized and characterized. These complexes are isostructural and have three‐dimensional structures (3D) composed of a pair of entanglement double helixes. The structure is an open framework with rhombic channels filled with uncoordinated water molecules. The photoluminescence properties of the SmIII complex (1) and EuIII/TbIII‐doped complex were explored by adjusting the excitation wavelengths. Interestingly, SmIII complex 1 generated a white‐light emission, whereas the EuIII/TbIII‐doped complex (Tb0.95Eu0.05) allowed the realization of white‐light emission under broad UV wavelengths. An energy transfer for TbIII 5D4→EuIII 5D0 was observed.

Synthesis and characterization of bis (acetylacetonato κ-O, O') [zinc(ii)/copper(ii)] hybrid organic-inorganic complexes as solid metal organic precursors.

We have synthesized novel metal organic hybrid mixed compounds of bis (acetylacetonato κ-O, O') [zinc(ii)/copper(ii)]. Taking C10H14O4Zn0.7Cu0.3 (Z0.7C0.3AA) as an example, the crystals are composed of Z0.7C0.3AA units and uncoordinated water molecules. Single-crystal X-ray diffraction results show that the complex Z0.7C0.3AA crystallizes in the monoclinic system, space group P21/n. The unit cell dimensions are a = 10.329(4) Å, b = 4.6947(18) Å, and c = 11.369(4) Å; the angles are α = 90°, β = 91.881(6)°, and γ = 90°, the volume is 551.0(4) Å(3), and Z = 2. In this process, the M(ii) ions of Zn and Cu mix and occupy the centers of symmetrical structural units, which are coordinated to two ligands. The measured bond lengths and angles of O-M-O vary with the ratio of metal species over the entire series of the complexes synthesized. The chemistry of the as-synthesized compounds has been characterized using infrared spectroscopy, mass spectroscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy analysis, and the morphology of the products has been characterized using scanning electron microscopy. The thermal decomposition of the Z0.7C0.3AA composites measured by thermogravimetric analysis suggests that these complexes are volatile. The thermal characteristics of these complexes make them attractive precursors for metal organic chemical vapor deposition.

SYNTHESIS, CRYSTAL STRUCTURE, SPECTROSCOPY PROPERTIES AND POTENTIAL ANTIMICROBIAL POTENTIALITIES OF A NEW SYNTHETIC COMPOUND: AMINO- CHLOROPYRIDINIUM DIAQUA DIOXALATO IRON(III)

We report herein the synthesis and the physicochemical characterization of a new mixed-ligand iron(III) complex of formula (C5H6ClN2)[Fe(C2O4)2(H2O)2].2H2O. This compound has been prepared by slow evaporation at room temperature and characterized by single crystal X-ray diffraction. It has been characterized by IR and UV-VIS spectra and thermal analysis (TG and DTA). In this compound, the iron ion has a slightly distorted square bipyramidal environment, coordinated by two chelating oxalate ion and two water molecules. Structural cohesion is established essentially by π-π interactions between the rings of pyridine groups and intermolecular hydrogen bonds connecting the ionic entities and uncoordinated water molecules. In vitro antimicrobial activities of the amino- chloropyridinium diaqua dioxalato iron (III) against pathogenic fungi, yeast and bacteria were studied in this work. On the whole, our new compound has high antibacterial activities against Pseudomonas aeruginosa, Staphylococcus aureus and Listeria innocua. The amino- chloropyridinium diaqua dioxalato iron (III) used at 200µg m-1, can reduce Candida albicans survival of about 45.45%, and destruct hyphe mycelial of Trichophyton rubrum. High lysozyme activities were expressed especially against Listeria innocua with 17 times more than Staphylococcus aureus. The minimal inhibitory concentrations (MIC) are ranging from 16 µg ml-1 for bacteria to 256 µg ml-1 for yeast and IC50 values varying from 1.44 to 10.45 µg ml-1 for bacteria and 45.8 for yeast.