Complexes of Cu(II) and Co(II) nitrates with 3-Phenyl-5,5-dimethyl-5,6-dihydro-1,2,4-triazolo[3,4-a]isoquinoline

Complexes of Cu(II) and Co(II) nitrates with 3-phenyl-5,5-dimethyl-5,6-dihydro-1,2,4-triazolo[3,4-a]isoquinoline (L⁰) of the composition [CuL ₂ ⁰ (NO₃)₂] (I) and [CoL ₂ ⁰ (NO₃)₂] · CH₃CN (II) are synthesized and their crystal structures are determined by X-ray diffraction. The L⁰ ligand is coordinated to the metal atoms through the N atom in position 2 of triazole fragment. The coordination polyhedron of the Cu(II) atom is a square with two additional axial vertices, while that of the Co(II) atom is a tetrahedron with two additional vertices. The NO ₃ ^? groups in the structures of I and II perform similar anisobidentate function. Complexes I and II are studied by IR and electronic spectroscopy.     

Syntheses, structures, and properties of zinc(II), cadmium(II), cobalt(II), and manganese(II) coordination polymers with tetraiodoterephthalate

The coordination chemistry of a rigid periodinated ligand, 2,3,5,6-tetraiodo-1,4-benzenedicarboxylic acid (H₂BDC-I₄), with a series of transition metal ions has been explored to afford five new coordination polymers {[M(BDC-I₄)(MeOH)₄](H₂BDC-I₄)(MeOH)₂} _n (M?=?Zn^II for 1, Cd^II for 2, Co^II for 3 and Mn^II for 4) and {[Mn(BDC-I₄)(MeOH)₄](DMF)} _n (5). All these complexes have been characterized by elemental analysis, IR spectroscopy, thermogravimetric (TG) analysis, and X-ray crystallography. Single-crystal X-ray diffraction reveals that complexes 1?C4 are isostructural and have a one-dimensional chain structure. Upon the addition of the solvent DMF, the infinite linear chain array in 4 is converted to a 1-D wave-like chain motif in 5 with a different space group ( $ P\overline{1} $ for 4 and P2₁/c for 5). The difference between structures 1?C4 and 5 can be attributed to the coordination mode of carboxylate changing from trans to cis fashion. The Zn^II and Cd^II complexes 1 and 2 display similar emissions in the solid state, which essentially are intraligand transitions.     

Hydrothermal synthesis, crystal structures, and properties of two Co(II) complexes based on 4-bromoisophthalic acid and N-donor ligands

Two new Co(II) complexes, [Co₂(H₂O)(Bipy)₂(Bript)₂] _n (I) and [Co(H₂O)(Phen)(Bript)] · H₂O (II), where H₂Bript = 4-bromoisophthalic acid, Bipy = 2,2??-bipyridine, and Phen = 1,10-phenanthroline, have been synthesized and characterized by elemental analysis, IR, and single-crystal X-ray diffraction. Complex I has binuclear units in which two Co²⁺ ions are bridged by two carboxylate groups and a coordinaiod-water molecule, and the binuclear units are connected by Bript to generate a 1D helical chain. These 1D helical chains are further linked by ????? stacking interactions to form a 3D supramolecular network, while complex II has a 2D layer motif. In I and II, there exists extensive hydrogen bonding interactions. The thermal behavior of the two corresponding complexes have briefly been investigated.     

Synthesis, crystal structures and electrochemical properties of CoIII complexes with hexadentate ligand containing thioether-amidopyridyl donor set

Two new cobalt(III) complexes of the hexadentate ligand [1,4-bis[o-(pyridine-2-carboxamidophenyl)]-1,4-dithiobutane] (H₂bpctb) with N₄S₂ donor set atoms have been synthesized. A reaction of Co(CH₃COO)₂·4H₂O with (H₂bpctb) leads to the formation of [Co^III(bpctb)]PF₆ (1) having a CoN₂(pyridine)N′₂(amide)S₂(thioether) coordination by symmetric bpctb^2? ligand. A similar reaction under slightly different conditions, however, gives [Co^III(L ^a )(L ^b )] (2), resulting from a C–S bond cleavage reaction triggered by an acetate ion as a base, having CoN₂(pyridine)N′₂(amide)S(thioether)S′(thiolate) coordination. These two Co(III) complexes have been characterized by elemental analyses and spectroscopic methods, and the crystal and molecular structures of [Co^III(bpctb)]PF₆ (1) in the form of the solvate (1·MeOH·H₂O) and of [Co^III(L ^a )(L ^b )] (2) have been determined by X-ray crystallography. The Co atoms of both complexes exhibit distorted octahedral geometry. The electrochemical investigation of [Co(bpctb)]PF₆·MeOH·H₂O (1·MeOH·H₂O) and [Co^III(L ^a )(L ^b )] (2) by cyclic voltammetry reveals a reversible Co^III–Co^II redox process at E _1/2 = ?0.32 V (ΔE _p = 80 mV); for 1, and E _1/2 = ?0. 87 V (ΔE _p = 70 mV) for 2.     

Tansition metal complexes with 2-(1-(carboxymethyl)-2-methyl-1H-benzimidazol-3-ium-3-yl)acetate (HL): Synthesis and crystal structure of [Co(L)2(H2O)4] · 6H2O and [Cu(L)2(H2O)2] · 4H2O

Transition metal complexes of 2-(1-(carboxymethyl)-2-methyl-1H-benzimidazol-3-ium-3-yl)acetate (HL), namely [Co(L)₂(H₂O)₄] · 6H₂O (I) and [Cu(L)₂(H₂O)₂] · 4H₂O (II), have been synthesized by a hydrothermal procedure and characterized by X-ray crystallography, CIF files CCDC nos. 1007524 (I), 1007525 (II). Both I and II are mononuclear molecules. In I, the Co²⁺ ion is in octahedral coordiantion environment and surrounded by four O atoms from water molecules and two carboxylate O atoms of two deprotonated ligand (L^?) occupied six culmination. While in II, the Cu²⁺ ion is located in a square-planar geometry, bounded to two aqua O atoms and two carboxylate O atoms from L^?.     

Synthesis, crystal structures, and properties of inorganic-organic hybrid complexes constructed from copper(II) macrocyclic fragment

Reaction of a macrocyclic copper(II) complex [Cu(L)](ClO₄)₂ · 3H₂O (I) (L = 1,3,10,12,16,19-hexaazatetracyclotetracosane) with a hexapod carboxylate ligand H₆TTHA (H₆TTHA = 1,3,5-triazine-2,4,6-triamine hexaacetic acid) and a tripod carboxylate ligand H₃TATB (H₃TATB = 4,4′,4″-S-triazine-2,4,6-triyl-tribenzoic acid) yielded two mononuclear copper(II) complexes [Cu(L)][H₄TTHA] · 4H₂O (II) and [Cu(L)][HTATB] · 4H₂O (III). The complexes I–III have been structurally characterized. The crystal structures of complexes II and III show the copper(II) ion has a distorted pentacoordinate square-pyramidal geometry with two secondary and two tertiary amines from the macrocyclic complex [Cu(L)]²⁺ and one oxygen atom from the carboxylate ligand group at the axial position. The UV-Vis spectra are utilized to discuss the hydrolysis of the complex II.     

Heterometallic complexes of macrocyclic oxamide with polycarboxylates: Syntheses,crystal structures,and magnetic properties

Three complexes with the formula [Co(Ip)(CuL)(H₂O)₂] · H₂O (I), [Co(Ip)(NiL)(H₂O)₂] · H₂O (II), [Co(CuL)₂(Hbtc)(H₂O)] (III), (H₂Ip = m-isophthalic acid; H₂L = 2,3-dioxo-5,6,14,15-dibenzo-1,4,8,12-tetraazacyclo-pentadeca-7,13-dien; H₃Btc = 1,3,5-benzenetricarboxylic acid) were synthesized and structurally characterized by elemental analysis, IR and UV spectroscopy. Single-crystal X-ray analyses reveal that the complexes I and II contain neutral heterometallic binuclear CoM (for I and II, M = Cu, Ni, respectively) moieties, and complex III contains discrete neutral trinuclear CoCu₂ moieties. The structures of I–III consist of two-dimensional supramolecular architecture formed by strong O-H…O intermolecular hydrogen bonds. Furthermore, the magnetic properties of complex I were investigated and discussed in detail.     

Cyanide-bridged one-dimensional bimetallic complexes based on a tridentate copper(II) building block: synthesis,crystal structures and magnetic properties

The reactions of [M^III(CN)₆]^3? (M = Cr or Co) with Cu^II complexes of a tridentate schiff base [Cu(aemp)Cl] or [Cu(aemp)Ac]₂ (Haemp = 2-[(2-amino-ethylimino)-methyl]-phenol) give rise to 1D cyanide-bridged bimetallic coordination polymers [Cu₄(aemp)₄(H₂O)₂][Cr(CN)₆]Cl (1) and [Cu₃(aemp)₃(H₂O)][Co(CN)₆]·2H₂O·MeOH (2). In complex 1, the six cyanide ligands of the [Cr(CN)₆]^3? moiety are involved in bridging, while in complex 2 only five cyanide ligands act as bridges to give a neutral chain. Magnetic studies reveal that complex 1 exhibits intermetallic ferromagnetic coupling, with J = 8.2 cm^?1.     

Di- and tetranuclear heterometallic CuII-LnIII complexes (Ln = Gd and Dy): Synthesis, structure and magnetic properties

Four 3d-4f heterometallic complexes, [CuⅡ LnⅢ (bpt) 2 (NO 3 ) 3 (MeOH)] (Ln = Gd, 1; Dy, 2; bptH = 3,5-bis(pyrid-2-yl)-1,2,4- triazole), [CuⅡ 2 LnⅢ 2 (μ-OH) 2 (bpt) 4 Cl 4 (H 2 O) 2 ]·6H 2 O (Ln = Gd, 3; Dy, 4), have been synthesized under solvothermal conditions. X-ray structural analyses reveal that 1 and 2 are isostructural while 3 and 4 are isostructural. In each complex, the copper and gadolinium or dysprosium ions are linked by two triazolate bridges and form a CuⅡ -LnⅢ dinuclear unit. The intramolecular Cu-Ln distances are 4.542, 4.525, 4.545 and 4.538 for 1, 2, 3 and 4, respectively. Two dinuclear CuLn units are bridged by two OH- groups into the zig-zag tetranuclear {CuⅡ 2 LnⅢ 2 } structures with the Ln(Ⅲ) Ln(Ⅲ) distances of 3.742 and 3.684 for 3 and 4, respectively. Magnetic studies show that the antiferromagnetic CuⅡ-LnⅢ interactions occur in 1 (J CuGd = 0.21 cm-1 ) and 2. The antiferromagnetic interaction occurs in complex 3 with J CuGd = 0.82 cm-1 and J GdGd = 0.065 cm-1 , while dominant ferromagnetic interaction occurs in complex 4.     

Crystal and molecular structures of mixed-valence octanuclear cobalt(ii,iii) propionate and butyrate with an etagere-like core

The new mixed-valence octanuclear cobalt carboxylate complexes [Co^II ₄Co^III ₄(μ₄-O)₄-(μ₃-OMe)₄(μ-O₂CR)₆(O₂CR)₂(H₂O)₆]·4H₂O, where R = Et (3) or n-Pr (4), were investigated by X-ray diffraction analysis. Complexes 3 and 4 have a molecular octanuclear structure, and they are valence trapped, and contain four cobalt atoms Co³⁺ in the central cubane fragment with four cobalt atoms Co²⁺ at the periphery of the molecules. The molecules of the complexes are stabilized by four intramolecular hydrogen bonds and are linked, together with water solvent molecules, by intermolecular hydrogen bonds to form a three-dimensional supramolecular system.     

Synthesis, spectroscopic, and thermal investigation of transition and non-transition complexes of metformin as potential insulin-mimetic agents

Complexes of [Mn(MF)₂(Cl)₂]·2H₂O (1), [Fe(MF)₂(Cl)₂]Cl·4H₂O (2), [Ni(MF·HCl)₂(Cl)₂]·6H₂O (3), [Cu(MF·HCl)₂(Cl)₂] (4), [Zn(MF·HCl)₂](NO₃)₂·6H₂O (5), [Cd₂(MF·HCl)(Cl)₄(H₂O)] (6), [Mg(MF·HCl)₂(Cl)₂]·6H₂O (7), [Sr₂(MF·HCl)(Cl)₄(H₂O)] (8), [Ba(MF·HCl)₂(Cl)₂]·2H₂O (9), [Pt(MF)₄] (10), [Au(MF)₃]Cl₃ (11), and [Pd(MF)₂]Cl₂ (12) were synthesized from Legitional behavior of metformin drug as a diabetic agent. The authenticity of the transition and non-transition metal complexes were characterized by elemental analyses, molar conductivity, (infrared, UV–Vis) spectra, effective magnetic moment in Bohr magnetons, electron spin resonance, thermal analysis, X-ray powder diffraction as well as scanning electron microscopy. Infrared spectral studies as well as elemental analyses revealed the existence of metformin in the base or hydrochloride salt forms in the chelation state acts as a bidentate ligand while the platinum(IV) complex is coordinated through the deprotonation of –NH group. The magnetic and electronic spectra of Mn(II), Fe(III), Ni(II), and Cu(II) complexes suggest an octahedral geometry. Antimicrobial screening of metformin and its complexes were determined against the (G⁺ and G^?) bacteria (Escherichia coli, Staphylococcus aureus, Bacillus subtilis, and Pseudomonas aeruginosa) and fungi (Aspergillus flavus and Candida albicans).     

Synthesis and crystal structure characterization of iron(II), cobalt(II) and nickel(II) complexes with 1,3-bis(2-pyridylmethylthio)propane

Three new mononuclear complexes of nitrogen–sulfur donor sets, formulated as [Fe^II(L)Cl₂] (1), [Co^II(L)Cl₂] (2) and [Ni^II(L)Cl₂] (3) where L = 1,3-bis(2-pyridylmethylthio)propane, were synthesized and isolated in their pure form. All the complexes were characterized by physicochemical and spectroscopic methods. The solid state structures of complexes 1 and 3 have been established by single crystal X-ray crystallography. The structural analysis evidences isomorphous crystals with the metal ion in a distorted octahedral geometry that comprises NSSN ligand donors with trans located pyridine rings and chlorides in cis positions. In dimethylformamide solution, the complexes were found to exhibit Fe^II/Fe^III, Co^II/Co^III and Ni^II/Ni^III quasi-reversible redox couples in cyclic voltammograms with E_1/2 values (versus Ag/AgCl at 298 K) of +0.295, +0.795 and +0.745 V for 1, 2 and 3, respectively.     

Synthesis and structural characterization of binuclear ytterbium(III) complexes with 2-amino and 3-amino benzoic acid

Two novel homobinuclear ytterbium(III) complexes, [Yb₂(2AMB)₆(H₂O)₄] · 2C₂H₆O (I) and Yb₂(3AMB)₆(H₂O)₄] · 3H₂O (II) (2AMB = 2-aminobenzoic acid, 3AMB = 3-aminobenzoic acid) have been synthesized and characterized by elemental analysis, infrared spectroscopy, thermogravimetric analysis and X-ray crystallography (CIF files CCDC nos. 950103 (I), 921652 (II)). Complex I crystallizes in triclinic space group \(P\bar 1\) and complex II crystallizes in monoclinic space group P2₁/n. X-ray analysis shows that both complexes (I, II) have the dinuclear structure. The central Yb³⁺ ions in both complexes are eight-coordinated adopting distorted YbO₈ dodecahedral geometry. Each Yb³⁺ ion is coordinated to two O atoms from bridging carboxylate, four O atoms from the chelating carboxylate ligands and two O atoms of water molecules. The crystal structure of I and II are stabilized by N-H…O, O-H…O, O-H…N, and C-H…O hydrogen bonds, C-H…π interactions and weak π-π stacking interactions.     

Synthesis, structural features and biological activities of three asymmetric pyridazine–triazole coordination polymers

The complexes [CuL₂Cl₂]_n (1), [CoL₂Cl₂(H₂O)₂]·L (2) and [MnL₂Cl₂(H₂O)₂]·L (3) (L = 3-chloro-6-(1H-1,2,4-triazol-1-yl) pyridazine) were synthesized and characterized by physicochemical and spectroscopic methods. X-ray crystallographic analysis reveals that the Cu(II) center of complex 1 is located in a slightly distorted tetragonal pyramidal environment and bridged by chlorine atoms to generate infinite 1D chains, which are further connected into 2D supramolecular structures by C–H…Cl hydrogen bonds. The Co(II) and Mn(II) atoms in complexes 2 and 3 both have a distorted octahedral coordination sphere, and the crystal lattices include hydrogen bonds and π–π stacking interactions to yield 3D supramolecular frameworks. The antioxidant activities (influence on O₂ ^?? and ^?OH) and antibacterial activities of the ligand L and its three complexes were also investigated.     

Supramolecular compounds constructed from Keggin anions and metal–organic complex cations of 3-aminopyrazine-2-carboxylic acid

Three new supramolecular compounds based on Keggin-type polyoxometalate (POM) and transition metal complexes, [M(Hapca)₂(H₂O)₂]₂[SiW₁₂O₄₀]·nH₂O, (M = Ni^II(1), Zn^II(2), n = 12; Co^II (3), n = 15; Hapca = 3-aminopyrazine-2-carboxylic acid), have been synthesized in aqueous solution and characterized by single-crystal X-ray diffraction, elemental analysis, TG analyses, IR and fluorescence spectroscopy. The X-ray structrual analysis reveals that three compounds are isostructural with a P21/c space group. [M(Hapca)₂(H₂O)₂] ₂ ⁴⁺ are linked together via O···N hydrogen-bonding interaction to give birth to 2D layer with rectangle grids. Anions [SiW₁₂O₄₀]^4? are located in the cavities and link the 2D layers into 3D supramolecular architecture via hydrogen bonds. The compounds represent the first examples of self-assembly of 2D metal–Hapca complex supramolecular “host” networks formed by hydrogen bonding interactions and “guest” polyoxoanion species. In addition, solid-state luminescence properties of compounds 2 and 3 have been studied at room temperature.     

A Salt-Like Compound Containing the Cation [Tris(1,10-Phenanthroline)manganese(II)](2+) and the Anion 3,3-Commo-Bis[η5-1,2-Dicarba-(3)-Cobalt(III)-closo-Dodecaborate](1–), [MnII(1,10-C12H8N2)3]2+{CoIII[η5-(3)-1,2-B9C2H11]2}– 2: Synthesis and Study

In this paper, the results of a comparative study of a salt-like paramagnetic Mn(II) (d ⁵) complex [Mn^II(1,10-C₁₂H₈N₂)₃]²⁺[Co^III(B₉C₂H₁₁)₂]^– ₂ (I) against [Mn^II(1,10-C₁₂H₈N₂)₂(NCS)₂]⁰ (II) and [Mn^II(1,10-C₁₂H₈N₂)₃]²⁺[B₉C₂H₁₂]^– ₂ (III) are presented. Complexes I and III were synthesized by precipitating the Mn(II) cations with the corresponding anions in the stoichiometric ratio at a pH of ～ 4.5 and were studied by X-ray diffraction analysis on single crystals; by IR, Raman, and EPR spectroscopy; and using magnetochemical methods. The structures and crystal-chemical parameters of I at 190 and 293 K are identical. The crystals are mono-clinic; space group P2₁/n. Two crystallographic types of the [Co(B₉C₂H₁₁)₂]^– anion in structure I have different conformational combinations (cisoid and transoid) of the –C₂– groups in each pair of the B₉C₂H^2– ₁₁ cluster ligands. The short contacts C–H^δ+···^δ–H–B between different-type hydrogen atoms show themselves in the IR spectra. The apparent magnetic moments of the Mn(II) atom in I, II, and III at 293 K correspond to μ = 5.86 μ_B and do not depend on its ligand or anion environment. The temperature dependences μ = f(T) pass through a maximum at about 20 K, which suggests the occurrence of ferromagnetic exchange interactions in complexes I and III, which both contain cluster carborane derivatives with three-dimensional aromaticity.     

Manganese(III) complexes with tetradentate (N2O2) Schiff bases and dicyanamide

New Mn(III) complexes with Schiff bases and dicyanamide are synthesized: [Mn(Salpn)N(CN)₂] _n (two polymorphous modifications, Ia and Ib), {[Mn(5-BrSalen)N(CN)₂] · CH₃OH} _n (II), and [Mn(3-MeOSalen)N(CN)₂(H₂O)] (III), where SalpnH₂ = N,N′-bis(salicylidene)-1,3-diaminopropane, 5-BrSalenH₂ = N,N′-bis(5-bromosalicylidene)-1,2-diaminoethane, and 3-MeOSalenH₂ = N,N′-bis(3-methoxysalicylidene)-1,2-diaminoethane. Complexes Ia, Ib, and II have the polymer structure in which the dicyanamide anion binds the paramagnetic Mn(III) complexes with the Schiff bases into one-dimensional chains. Unlike them, in complex III the monomer units containing water and the dicyanamide anion as terminal ligands form dimers due to hydrogen bonds. The study of the magnetic properties of complexes Ia and II shows a weak antiferromagnetic interaction between the Mn³⁺ ions through the dicyanamide bridges in these complexes.     

Inclusion of Cl− or Br− anions within host framework formed by second-sphere interactions

In this study, we have deliberately utilized the second-sphere coordination approach into the construction of supramolecular inclusion solids Cl ? [H₂ L1]·[InCl₄] (Crystal I) and Br ? [H₂ L1]·[TeBr₆] (Crystal II). The chloride or bromine anions can be encapsulated inside the host assemblies formed by the diamine molecule (4,6-dimethyl-1,3-phenylene) bis(N,N-dibenzylmethane) (L1) and the metal complexes ([InCl₄]^? and [TeBr₆]^2?) via second-sphere interactions. The inclusion complexes have been structurally characterized by X-ray crystallography, indicating that weak C–H···Cl and C–H···Br hydrogen bonding synthons play a significant role in the construction of host framework. 2-D networks are formed in both complexes by the interconnection of 1-D networks through the multiple weak hydrogen bonding interactions with [InCl₄]^? or [TeBr₆]^2?. The guest Cl^? or Br^? anions are encapsulated inside the host cages through N–H···Cl hydrogen bonds. The inclusion selectively was studied for the two host assemblies.     

Solventothermal syntheses, structures and photoluminescence of two-dimensional lanthanide coordination polymers with adipic acid

Four lanthanide coordination polymers formulated as [Ln₂(Ad)₃(H₂O)₄] · 0.25H₂O ( Ln = Tb (I), Pr (II), Ho (III), Dy (IV); H₂Ad = adipic acid), have been solventothermally synthesized from the self-assembly of the lanthanide ions (Ln³⁺) with the exible adipic dicarboxylate ligand. All of them were characterized by IR spectroscopy and single-crystal X-ray diffraction. Structural analyses revealed that these complexes had intricate two-dimensional interpenetrated metal-organic networks. In addition, the photoluminescent properties of complex I was discussed in detail, which shows strong green emission, corresponds to ⁵ D ₄ → ⁷ F ₅ transition of Tb³⁺ ions.     

Synthesis and study of tetraamminecobalt hydrogen hexamolybdometalates(III)

Tetraamminecobalt hydrogen hexamolybdoferrate [Co(NH₃)₄] · H[FeMo₆O₁₈(OH)₆] · 6H₂O (I) and tetraamminecobalt hydrogen hexamolybdogallate(III) [Co(NH₃)₄] · H[GaMo₆O₁₈(OH)₆] · 6H₂O (II) were synthesized and studied by mass spectrometry, thermogravimetry, IR spectroscopy, and X-ray diffraction. Crystals of I and II are monoclinic; a = 16.21 Å, b = 5.43 Å, c = 12.32 Å, β = 119.63°, V = 1092.11 ų, ρ_calcd = 2.21 g/cm³, and Z = 1 for I; a = 16.24 Å, b = 5.59 Å, c = 12.29 Å, β = 119.79°, V = 1064.05 ų, ρ_calcd = 2.15 g/cm³, and Z = 1 for II. Compounds I and II were used as catalysts for soft oxidation of natural gas.