Formation and coordination of a terdentate dithiocarbazatopyrazoline derivative to technetium(V)

The potentially terdentate ligand 1-(S-methyldithio)-3,5-dimethyl-3-(S-methyldithiocarbazato)pyrazoline (H₂mdp) was prepared by the reaction of S-methyldithiocarbazate with acetylacetone in an acidic ethanol solution. The neutral complex [TcOCl(mdp)](1) was formed by the reaction of (n-Bu₄N)[TcOCl₄] with H₂mdp in ethanol at room temperature. Compound 1 has a square-pyramidal geometry with the thiolate, thiocarbonyl and amide donor atoms of the terdentate chelate mdp and chloride forming a square plane, with the oxo oxygen in the apical position.     

Synthesis,characterization and structure of oxorhenium(V) complexes with 2-methylmercaptobenzamide

The neutral, mononuclear complex [ReO(mta)₂Cl] (1) [Hmta?=?2-(methylmercapto)aniline] was prepared by reaction of trans-[ReOCl₃(PPh₃)₂] with a twofold molar excess of Hmta in methanol. The oxo-bridged dimer (μ-O)[ReO(mta)₂]₂ (2) was synthesized by reacting [ReOCl₃(PPh₃)₂] with a twofold excess of Hmta in a 9?:?1 acetone/water mixture. The compounds were characterized by spectroscopy and complex 1 also by X-ray crystallography. Complex 1 has a distorted octahedral geometry with the chloride coordinated trans to the oxo group, and with the chelating ligands in the equatorial plane in a cis-N cis-S configuration.     

A trigonal-bipyramidal oxorhenium(V) complex with a bidentate nitrogen-donor ligand

The oxorhenium(V) complex [ReO(Hapb)(apb)] (1) (H₂apb =?2-(2-aminophenyl)-1-benzimidazole) was prepared by reaction of trans-[ReO₂(py)₄]Cl with a twofold molar amount of H₂apb. The complex was characterized by spectroscopy and X-ray crystallography. The results show that the rhenium atom lies in a distorted trigonal-bipyramidal environment, with the two imidazole nitrogen atoms in apical positions, and the oxo and two amido nitrogens in the trigonal plane.     

Syntheses,crystal structures,and photophysical properties of two 2-D coordination polymers

Two coordination polymers, [Mn(dipt)(m-BDC)₃] _n (1) and [Pb(mip)(1,4-NDC)] _n (2) [dipt?=?2-(2,4-dichlorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline, mip?=?2-(3-methoxyphenyl)-1H-imidazo[4,5-f][1,10]phenanthroline, m-BDC?=?isophthalic acid, 1,4-NDC?=?naphthalene-1,4-dicarboxylic acid], have been synthesized by hydrothermal reactions and characterized by elemental analysis, thermogravimetric analysis, infrared spectrum, and single-crystal X-ray diffraction. Single-crystal X-ray diffraction reveals that 1 and 2 have 1-D chain architecture. Complex 1 has a 2-D-layered structure constructed from C–H···O hydrogen bonds. Complex 2 has a 2-D-layered structure constructed from N–H···O hydrogen bonds and π–π interactions. TG analyses suggest 1 and 2 have excellent thermal stabilities from hydrogen bonds and π–π interactions. Mn(II) in 1 has trigonal bipyramidal geometry surrounded by three carboxylate oxygen atoms from three monodentate bridging m-BDC and two nitrogen atoms from one dipt. Pb(II) has [:PbN2O4] pentagonal bipyramidal geometry in 2. The luminescent properties for dipt, mip, 1, and 2 are also presented.     

Synthesis,crystal structures and toxicity of bicadmium(ii) complexes with macrocyclic,hexaaza-bearing,hydroxyethyl pendants

Three bicadmium(II) complexes with hydroxyethyl pendants were synthesized by [2?+?2] Schiff-base condensation of 2-[bis(2-aminoethyl)amino]ethanol with sodium 2,6-diformyl-4-R-phenolate (for Complex 1, R?=?F; Complex 2, R?=?Cl; Complex 3, R?=?CH₃) in the presence of Cd²⁺. Crystals of 1 were monoclinic, space group P2₁/c, with a?=?16.251(9), b?=?21.424(11), c?=?12.994(7)?Å and β?=?106.622(9)°. Both Cd(II) atoms were heptacoordinated with monocapped-octahedral geometry. Complex 3 crystals were isolated as triclinic, space group P?1 with α?=?15.502(4), b?=?16.060(4), c?=?16.642(5)?Å and α?=?68.813(4), β?=?80.836(4), γ?= 86.551(4)°. The coordination number and coordination geometry of the Cd ion in one cationic unit of 3 are similar to that of 1, while in the other cationic unit, one Cd atom is N₃O₄ heptacoordinated and the other Cd atom has an N₃O₃ coordination environment and possesses a distorted octahedral geometry. The toxicity of these complexes was evaluated by testing antimicrobial activity against bacterial strands.     

Synthesis and crystal structure of a trinuclear titanium(IV) β -diketonate complex with a six-membered [Ti–(μ-O)]3 ring

The trinuclear titanium(IV) β-diketonate complex, [Ti₃(μ-O)₃(dppd)₆]?·?(DMF)(0.5EtOH) (1) (H-dppd?=?1,3-diphenylpropane-1,3-dione) has been synthesized and its crystal structure and spectroscopic properties have been studied. Complex 1 crystallizes in monoclinic system with space group C2/c and a?=?20.954(5)?Å, b?=?18.705(4)?Å, c?=?24.617(6)?Å, β?=?111.957(4)°, Z?=?4. The complex consists of a six-membered [Ti–(μ-O)]₃ ring, of which three titanium(IV) ions are linked together by bridging oxygen atoms. Each titanium(IV) possesses an octahedral geometry, with four oxygen atoms from the two β-diketonate ligands and two bridging oxygen atoms.     

Syntheses and crystal structures of copper(II) complexes derived from 2,4,6-tris(2-pyridyl)-1,3,5-triazine

Treatment of freshly precipitated Cu(OH)₂?·?xH₂O and 2,4,6-tris(2-pyridyl)-1,3,5-triazine (tptz) with oxalic and malonic acids in methanol-water at room temperature gave [Cu(tptz)(C₂O₄)(H₂O)]?·?4H₂O (1) and [Cu(pma)(C₃H₂O₄)(H₂O)]?·?H₂O (2) (pma?=?2-aminocarbonylpyridine), respectively. Reaction in the absence of any acid resulted in [Cu(bpca)(tca)]?·?2H₂O (3) (bpca?=?bis(2-pyridylcarbonyl)amide anion; tca?=?2-pyridinecarboxylate anion). Complex 1 consists of [Cu(tptz)(C₂O₄)(H₂O)] and lattice H₂O molecules; the tridentate tptz ligand, bidentate oxalate dianion and an aqua ligand are bound to Cu with distorted octahedral geometry. Complex 2 is composed of [Cu(pma)(C₃H₂O₄)(H₂O)] and lattice H₂O molecules; the bidentate 2-aminocarbonylpyridine ligand, a bidentate malonate dianion and an aqua ligand are coordinated to Cu with a slightly distorted square pyramidal geometry. Complex 3 consists of [Cu(bpca)(tca)] and lattice H₂O molecules. Square pyramidally coordinated Cu atoms are surrounded by tridentate bpca with nitrogen donor atoms and a bidentate 2-pyridinecarboxylate anion.     

Syntheses, electrochemistry and crystal structure studies of novel cis-configuration biferrocene trinuclear complexes

The syntheses and characterization of novel biferrocene trinuclear complexes for Schiff base ligand, S-methyl-N-(ferrocenyl-1-methyl-methylidene)dithiocarbazate (hereafter abbreviate as HL), are described. X-ray diffraction studies established the structures of the palladium complex, PdL₂2 and the copper complex, CuL₂3. The geometry of Pd(II) in 2 is close to square planar and in novel cis-configuration with two ferrocene moieties in the same side, while that of Cu(II) in 3 is close to tetrahedral configuration. Electrochemical measurements suggest that the distorted square planar configuration of the Ni(II) and Pd(II) moieties, can effectively transmit the redox effects of the ferrocene moieties, while the distorted tetrahedral configuration of Cu(II) complex can not transmit the redox effects.     

Synthesis and structural characterization of two dimensional cadmium(II) coordination polymers

Reactions of Cd(NO₃)₂?·?4H₂O with NH₄SCN, ppz (ppz?=?piperazine) and bpa (bpa?=?bis(4-pyridyl)ethane) in CH₃OH afforded the cavity-containing rectangular grids {Cd(SCN)₂(ppz)} _n (1) and {Cd(NCS)₂(bpa)} _n (2). The ppz ligand in 1 is coordinated to the metal through both nitrogen atoms to form the 1-D zig-zag chain structure and distorted {CdN₄S₂} octahedral coordination geometry at each Cd center is completed by pairs of bidentate thiocyanato ligands. Complex 2 has the 2-D arrangement constructed through 1-D double μ(N,S) end-to-end bridging thiocyanato groups bridging Cd(II) chains interconnected through disordered bpa ligands.     

Syntheses,characterization and X-ray crystal structures of Co(III) and Mn(II) complexes of pyrimidine derived Schiff base ligands

Two pyrimidine based NNS tridentate Schiff base ligands S-methyl-3-((2-S-methyl-6-methyl-4-pyrimidyl)methyl)dithiocarbazate [HL₁] and S-benzyl-3-((2-S-methyl-6-methyl-4-pyrimidyl)methyl)dithiocarbazate [HL₂] have been synthesised by 1:1 condensation of 2-S-methylmercapto-6-methylpyrimidine-4-carbaldehyde and S-methyl/S-benzyl dithiocarbazate. One Co(III) and one Mn(II) complex of HL₁ and one Mn(II) complex of HL₂ have been prepared and characterized by elemental analyses, molar conductivities, magnetic susceptibilities and spectroscopic studies. All the bis-chelate complexes have a distorted octahedral arrangement with an N₄S₂ chromophore around the central metal ion. Each ligand molecule binds the metal ion using pyrimidyl nitrogen, azomethine nitrogen and the thiolato sulfur atoms. In the free ligand moieties, the pyrimidine nitrogen atoms, azomethine nitrogen atoms and thione sulfur atoms are in EEE orientation to each other. During chelation, all the donor sites of the ligands are reoriented to ZEZ configuration in order to facilitate the chelation process. In all the complexes, the respective ligand molecule functions as the monoanionic tridentate one. All complexes were analyzed by single crystal X-ray diffraction and significant differences concerning the distortion from octahedral geometry of the coordination environment were observed.     

Synthesis,structure and antimicrobial study of two new copper(II) complexes derived from N-(3-aminopropyl) benzylamine ligand (apba) and N-salicylidene-apba

Two new copper(II) complexes were synthesized by reaction of N-(3-aminopropyl)benzylamine (L1: apba, for complex 1) and N-salicylidene-apba (L2: for complex 2) with Cu²⁺. Crystals of complex 1 were orthorhombic, space group pccn, with a?=?15.2149(10), b?=?25.0071(16), c?=?7.6280(5)?Å and α?=?β?=?γ?=?90°. Complex 2 crystals were monoclinic, space group P2₁/c, with a?=?8.688(6), b?=?12.812(9), c?=?16.022(11)?Å and β?=?99.241(10)°. Structures of the two complexes were centro-symmetric and both Cu(II) atoms were four coordinate with a distorted square-planar geometry. The toxicity of the complexes was evaluated by testing antimicrobial activity against bacterial strands.     

Synthesis,characterization, and antibacterial activities of two new copper(II) glycinate complexes incorporating 2-(4′-thiazolyl)benzimidazole/2-(2-pyridyl)benzimidazole

Two new complexes, [Cu(TBZ)(Gly)(H₂O)]Cl (1) and [Cu(HPB)(Gly)Cl]?·?2H₂O (2) (TBZ?=?2-(4′-thiazolyl)benzimidazole, HPB?=?2-(2-pyridyl)benzimidazole, and Gly?=?glycinate), have been synthesized and characterized by elemental analysis, molar conductivity, UV-Vis, and IR methods. The complexes, structurally characterized by single-crystal X-ray crystallography, show a slightly distorted square-pyramidal coordination geometry in which two nitrogen atoms of TBZ or HPB and the carboxylate oxygen and amino nitrogen of glycinate bind in the plane and a water or chloride coordinated at the axial site. The complexes, free ligands, and copper(II) chloride were tested for their ability to inhibit growth of Bacillus subtilis, Staphylococcus aureus, and Salmonella. The results show that the complexes have good antibacterial activities against the microorganisms compared with their ligands and copper(II) chloride.     

Syntheses,crystal structures,and catalysis by polymeric dioxomolybdenum(VI) complexes with similar (iso)nicotinohydrazones

Polymeric dioxomolybdenum(VI) complexes, [MoO₂L]_n (L?=?L¹?=?N′-(2-hydroxybenzylidene)nicotinohydrazide for 1, L?=?L²?=?N′-(2-hydroxy-5-methoxybenzylidene)isonicotinohydrazide for 2), were prepared and characterized by physico-chemical, spectroscopic methods, and single-crystal X-ray determination. Complex 1 crystallizes in the orthorhombic space group P2₁2₁2₁ with a?=?7.6568(4), b?=?11.6315(7), c?=?15.2211(9)?Å, V?=?1355.59(13)?ų, Z?=?4, R ₁?=?0.0181, wR ₂?=?0.0464, and S?=?1.097. Complex 2 crystallizes in the monoclinic space group P2 ₁ /n with a?=?11.2516(6), b?=?11.8134(7), c?=?12.4371(6)?Å, β?=?116.2210(10)°, V?=?1483.02(14)?ų, Z?=?4, R ₁?=?0.0399, wR ₂?=?0.0874, and S?=?1.096. X-ray analysis indicates that Mo in each complex is octahedral with two oxo groups and N₂O₂ donor set of the nicotinohydrazone or isonicotinohydrazone. The complexes are efficient catalysts for oxidation of olefins.     

Synthesis and crystal structures of dichlorocyclopentadienyl β-diketonate titanium complexes

Complexes of acetylacetonatodichlorocyclopentadienyltitanium(IV) (1) and dichlorocyclopentadienyl(2,2,6,6-tetramethyl-3,5-heptanedionato)titanium(IV) (2) have been prepared and their crystal structures determined by X-ray diffraction methods. Complex 1 crystallizes in space group P2₁/m with a?=?7.1893(10), b?=?11.7680(17), c?=?7.6129(11) Å, β?=?109.901(12)°; complex 2 crystallizes in space group P2₁/n with a?=?10.065(2), b?=?16.322(3), c?=?12.219(2) Å, β?=?110.99(3)°. The molecular structures of 1 and 2 can be described as square-based pyramidal, with the centroid of the C₅H₅ ring occupying the apical site and the bidentate β-diketonate and two chloride ligands occupying the basal positions. The average distances between titanium and oxygen atoms are 1.991(2) and 1.967(3) Å in compounds 1 and 2, respectively.     

Thiocyanato-copper(II) complexes derived from a tridentate amine ligand and from alanine

Two thiocyanato-Cu(II) complexes including mononuclear dithiocyanato Cu(Me₃dpt)(NCS)₂ (1) and the polymeric 1D [Cu(d,l-Ala)(μ_N,S–NCS)(H₂O)] _n (2) were synthesized and structurally characterized (Me₃dpt = bis(N-methyl-3-propyl)methylamine, Ala = alaninate anion). The IR spectrum of complex 1 confirmed the N-bonding coordination mode of the thiocyanate groups, and its visible spectrum revealed the square pyramidal geometry around the central Cu²⁺ ion. Single X-ray crystallography of 1 showed that the Cu(II) center displays square pyramidal geometry with severe distortion toward trigonal bipyramidal environment. Complex 2 forms a 1-D polymeric chain with the NCS⁻ acting as a μ_N,S-ligand. A distorted SP geometry around the Cu²⁺ centers was achieved by the O and N atoms of alaninato anion, the aqua ligand and by the N and S atoms of the bridging thiocyanate groups. Hydrogen bonds of the type N–H···O, N–H···S and O–H···O are formed in this complex leading to the extension of the 1D chain to a supramolecular network.     

A novel copper(II) complex with 1,10‐phenanthroline and ciprofloxacin

The X‐ray structure analysis of the title compound, chloro[1‐cyclopropyl‐6‐fluoro‐1,4‐dihydro‐4‐oxo‐7‐(piperazin‐4‐ium‐1‐yl)‐3‐quinolinecarboxylate‐κ²O³,O⁴](1,10‐phenanthroline‐κ²N,N′)copper chloride dihydrate, [CuCl(C₁₇H₁₈FN₃O₃)(C₁₂H₈N₂)]Cl·2H₂O or [CuCl(cfH)(phen)]Cl·2H₂O, where cfH is 1‐cyclopropyl‐6‐fluoro‐1,4‐dihydro‐4‐oxo‐7‐(piperazin‐4‐ium‐1‐yl)‐3‐quinolinecarboxylate and phen is 1,10‐phenanthroline, shows that the geometry around the Cu ion is a slightly distorted square pyramid. Two O atoms of the carbonyl and carboxyl groups of ciprofloxacin and two N atoms of 1,10‐phenanthroline are coordinated to the metal centre in the equatorial plane, and a Cl⁻ ion is coordinated at the apical position. Extensive intermolecular hydrogen bonding produces a supramolecular structure that consists of alternating six‐ and 12‐membered rings.     

Different coordination modes of tetradentate Schiff bases in monomeric and dimeric oxorhenium(V) complexes

The reactions of the tetradentate amine-phenol type Schiff bases H₂sal₂en (1,2-ethylenebis(salicylideneimine) and H₂sal₂mp (1,2-benzylenebis(salicylideneimine)) with trans-[ReOCl₃(PPh₃)₂] or (n-Bu₄N)[ReOCl₄] in air gave the products (µ-O)[ReO(sal₂en)]₂ (1) and [ReOCl(sal₂mp)] (2), respectively. X-ray and spectroscopic studies have shown that 1 contains the linear O=Re–O–Re=O grouping, with the four donor atoms of sal₂en^2? coordinating in the square plane cis to the oxo ions. In 2, a cis oxo-chloro arrangement is observed with a phenolic oxygen being coordinated trans to the oxo group. The terminal Re=O bond lengths in 1 and 2 are 1.709(4) and 1.683(3)?Å, respectively.     

Supramolecular complexes constructed with carboxylate Cu(II) and 2-(2-pyridyl)-benzimidazole via hydrogen bonding

Four copper(II) supramolecular complexes, {[Cu(Hpb)(mal)]·H₂O} _n (1), (Hpb?=?2-(2-pyridyl)-benzimidazole, mal?=?maleate), [Cu₄(pb)₄(cro)₄(MeOH)₂]·2MeOH (2) (cro?=?crotonate), [Cu₂(pb)(Hpb)(mac)₃(MeOH)] (3) (mac?=?α-methacrylate) and [Cu(Hpb)(acr)₂(H₂O)] (4) (acr?=?acrylate), based on carboxylate copper(II)-aromatic ligand systems which are assembled by combination of metal coordination, hydrogen-bond and π–π interactions, have been rationally designed and synthesized. Complex 1 forms a 3D supramolecular network with open channels by extending 2D undulating sheets constructed from 1D helical chains. Complex 2 generates a 2D grid-like sheet via unusual finite-chain tetranuclear molecules, with four copper atoms arranged in a line; the unit does not extend further due to the capping effect of the terminal methanol. Complexes 3 and 4 present a 1D sinusoidal structure and a 3D columnar network with 1D ladder-shaped double chains, respectively. Interestingly, coligand Hpb, deprotonated or/and neutral in different supramolecular complexes, provides hydrogen bonding and π–π stacking interactions. In complexes 2, 3 and 4, carboxylate anions show various bridging modes, which are reflected in their magnetic properties. Weak ferromagnetic coupling (syn-anti µ-OCO) exists in 1, antiferromagnetic (syn-syn µ-OCO) and weak ferromagnetic coupling (µ-O of the??COO group) in 2 and antiferromagnetic coupling (syn-syn µ-OCO) in 3.     

Synthesis,structure and properties of a binuclear complex {[Mn(bpy)2(CuL)(H2O)2](ClO4)2} and its CuL precursor (H2L = 2,3-dioxo-5,6 : 14,15-dichlorobenzo-7,13-diphenyl-1,4,8,12-tetraazacyclo-pentadeca-7,12-diene)

A binuclear complex {[Mn(bpy)₂(CuL)(H₂O)₂](ClO₄)₂} (2) and its CuL (1) precursor (H₂L?=?2,3-dioxo-5,6?:?14,15-dichlorobenzo-7,13-diphenyl-1,4,8,12-tetraazacyclo-pentadeca-7,12-diene; bpy?=?2,2′-dipyridyl) have been synthesized and characterized structurally. Complex 1 consists of the neutral [CuL] fragments and methanol molecules. In complex 2, [Mn(bpy)₂(CuL)]²⁺ cation, two water molecules and two perchloric anions make up of the crystal. Mn(II) is coordinated by four nitrogen atoms from two 2,2′-dipyridyl and two oxygen atoms from the Cu(II) precursor. Magnetic characterization of 2 exhibits an antiferromagnetic interaction between Cu(II) and Mn(II) ions, with J?=??74.1?cm^?1.     

Syntheses,characterization, and X-ray crystal structures of two cis-dioxovanadium(V) complexes of pyrazole-derived,Schiff-base ligands

Two mononuclear cis-dioxovanadium(V) complexes of pyrazole-derived, Schiff-base ligands have been synthesized and characterized. Single crystal X-ray analyses were performed with N ′-[(3-methyl-1H-pyrazole-5-yl)carbonyl]pyridine-2-carbohadrazonamido cis-dioxovanadium(V), {[VO₂(PzOAP)] · H₂O} (1), and 5-methyl-N-[(1E)-1-(pyridin-2-yl)ethylidene]-1H-pyrazole-3-carbohydrazonate cis-dioxovanadium(V), {[VO₂(PzCAP)]} (2). Both complexes crystallize in monoclinic crystal systems with different space groups. Complex 1 crystallizes in the space group P21/c, 2 in space group C2/C. In each complex, the vanadium sits within a distorted square pyramidal geometry with an N₂O₃ chromophore. The τ parameters of the complexes (0.33 for 1, 0.22 for 2) support their square pyramidal geometry. The interesting finding in the work is that the alkoxide oxygen, imino nitrogen, and pyridine nitrogen take part in the coordination process leaving the pyrazole rings inactive in coordination.