Search

• A series of mixed-ligand Cu(II) complexes were synthesized and characterized. • The anti-lung cancer activity of these Cu complexes were evaluated in vitro. • We revealed the anticancer mechanism of the Cu(II) complex. • The ability of complex 4 to inhibit the growth of A549 tumor spheroids was assessed. [Display omitted] Here we synthesized five mixed-ligand copper(II) Schiff-base complexes, including [Cu(HL1)(pyridine) NO 3 ] 1 , [Cu(HL2)(pyridine)Cl] 2 , [Cu(HL3)(pyridine)Br] 3 , [Cu(HL4)(pyridine)Br] 4 , and [Cu(L5)(pyridine)] 5 , and performed a series of assays to investigate their anti-lung cancer activities in vitro. The structures of these copper(II) complexes were confirmed by X-ray crystallography and elemental analysis. MTT assay showed that complex 4 exhibited stronger cytotoxicity than other complexes. The wound healing assay showed that complex 4 had the well potential to display anti-metastatic activity. Flow cytometry and fluorescence imaging analysis showed that complex 4 led to cell cycle arrest at the S phase and induced mitochondria-mediated apoptotic. Furthermore, in the 3D A549 spherical model, complex 4 clearly exerts an inhibitory effect. [ABSTRACT FROM AUTHOR]

The self-assembly of Zn(NO 3) 2 ·6H 2 O, benzene-p-dicarboxylic acid (H 2 BDC) and tris(4-(4H-1,2,4-triazol-4-yl)phenyl)amine (L) affords a new Zn(II)-based metal-organic framework (MOF) with the formula of {[Zn 3 (L)(BDC) 3 (H 2 O) 3 ]·3.5H 2 O} n (1). The structural determination results reveal that complex 1 demonstrates a 8-fold interpenetrated three-dimensional network with a 3-connected srs net. The photoluminescent study shows that the interligand-based charge-transfer contributes to the strong emission of 1 ​at room temperature. Furthermore, complex 1 could be applied as an efficient photocatalyst for the elimination of Rhodamine B (RhB), methyl orange (MO) and methylene blue (MB) with the degradation efficiency all above 90% within 70 ​min under UV light irradiation. In connection to this, the detailed degradation mechanism has been probed both experimentally and computationally. A new Zn(II)-based metal-organic framework has been prepared using the dual-ligand approach. The structural determination results reveal that this MOF demonstrates a 8-fold interpenetrated three-dimensional network with a 3-connected srs net. The photoluminescent study shows that the interligand-based charge-transfer contributes to the strong emission of 1 ​at room temperature. Furthermore, this MOF could be applied as an efficient photocatalyst for the elimination of Rhodamine B, methyl orange and methylene blue with the degradation efficiency all above 90% within 70 ​min under UV irradiation. In connection to this, the detailed degradation mechanism has been probed both experimentally and computationally. [Display omitted] • A new Zn(II)-MOF with 8-fold interpenetrated net was prepared. • This Zn(II)-MOF is stable in water for at least three days. • This MOF shows insensitive luminescent emission due to the inter-ligand based charge transfer. • This MOF could be used as a photocatalyst for photodegradation of dyes. [ABSTRACT FROM AUTHOR]

Two new mixed-ligand complexes of formula [Cu(mal)(abpt)(H2O)].3/2H2O (1) and [Cu2(sq)(abpt)2].2H2O (2) [mal = malonate, abpt = 4-amino-3,5-di-2-pyridyl-4H-1,2,4 triazole and sq = squarate], have been prepared and characterized by X-ray crystal structure determination and magnetic studies. Complex 1 crystallizes in the monoclinic system, space group C2/c, with a = 14.0086(2) Å, b = 10.0980(2) Å, c = 25.630(4) Å; β = 97.5900(10) o, and Z = 8. Complex 2 crystallizes in the triclinic system, space group P-1 with a = 7.5696(15) Å, b = 8.4697(17) Å, c = 11.049(2) Å; β = 93.00(3)o, α = 96.98(3), γ = 90.111(3) and Z = 1. Complex 1 consist of a neutral mononuclear [Cu(mal)(abpt)(H2O)] unit and water molecule of crystallization in a distorted square pyramidal coordination sphere, while complex 2 is viewed as being made up of [Cu(sq)(abpt)2] units with the squarato ligand bridging the two copper(II) cations. Variable temperature magnetic behaviour of the complexes reveals the existence of weak antiferromagnetic interaction for complex 1 and weak ferromagnetic intrachain interaction for complex 2.

Three novel coordination polymers, formulated as {[Zn(1,4-bmimb)(PhAA)2]·H2O}n (1), [Cu(1,4-bmimb)0.5(2,6-PyDC)]n (2), and {[Cu(1,4-bmimb)0.5(2-PAC)(HCOO)]·2H2O}n (3) (1,4-bmimb = 1,4-bis((2-methyl-1H-imidazol-1-yl)methyl)benzene; PhAA = phenylacetic acid; 2,6-PyDC = pyridine-2,6-dicarboxylic acid; 2-PAC = 2-pyrazinecarboxylic acid), were synthesized by the self-assembly of mixed ligands with Zn(II) and Cu(II) under solvothermal conditions and characterized by means of single-crystal X-ray diffraction, X-ray powder diffraction, infrared spectra, thermogravimetric analysis, fluorescence spectra and UV-vis absorption spectra. 1 is shown as a Z-shaped chain, which is formed by Zn2+, PhAA ligands, and 1,4-bmimb ligands, and is assembled into a 3D structure by hydrogen bonding and π···π interaction. Similarly, 2 displays a single chain, which is built by Cu2+, 2,6-PyDC ligands, and 1,4-bmimb ligands, and is assembled into a 3D structure by hydrogen bonding and π···π interaction. 3 possesses a 1D ladder structure, which is formed by Cu2+, 2,6-PyDC ligands, and 1,4-bmimb ligands, and is assembled into a 3D structure by hydrogen bonding. The luminescence properties (for 1) and UV-vis spectrum (for 2 and 3) were also studied and discussed.

The linker 2,5-di(4-pyridyl)thiazolo[5,4-d]thiazole (Dptztz), whose synthesis and structure is described here, was utilized together with benzene-1,3-dicarboxylate (isophthalate, 1,3-BDC2−) for the preparation of the two-dimensional coordination network [Zn(1,3-BDC)Dptztz]·DMF (DMF = dimethylformamide) via a solvothermal reaction. Compound [Zn(1,3-BDC)Dptztz]·DMF belongs to the class of coordination polymers with interdigitated structure (CIDs). The incorporated DMF solvent molecules can be removed through solvent exchange and evacuation such that the supramolecular 3D packing of the 2D networks retains porosity for CO2 adsorption in activated [Zn(1,3-BDC)Dptztz]. The first sorption study of a tztz-functionalized porous metal-organic framework material yields a BET surface of 417 m2/g calculated from the CO2 adsorption data. The heat of adsorption for CO2 exhibits a relative maximum with 27.7 kJ/mol at an adsorbed CO2 amount of about 4 cm3/g STP, which is interpreted as a gate-opening effect.

A novel 3D NbO metal-organic framework, [Cd 2 (pam) 2 (bpt) 2 (H 2 O)] n ·0.68nH 2 O ( 1 ) (H 2 pam = pamoic acid and bpt = 2,5- bis (4-pyridyl)-1,3,4-thiadiazole), has been synthesized by the structural cooperation of well-chosen flexible aromatic acid and rigid bipyridyl ligand. The rare severely distorted mixed-ligand mesomeric networks accommodate two individual heterochiral frameworks interpenetrating with each other. The bulk materials of 1 display excellent fluorescent properties. [ABSTRACT FROM AUTHOR]

The hydronium salt (H3O)2[Cu(N7-acv)2(H2O)2(SO4)2]·2H2O (1, acv = acyclovir) has been synthesized and characterized by single-crystal X-ray diffraction and spectral methods. Solvated Cu(OH)2 is a by-product of the synthesis. In the all-trans centrosymmetric complex anion, (a) the Cu(II) atom exhibits an elongated octahedral coordination; (b) the metal-binding pattern of acyclovir (acv) consists of a Cu-N7(acv) bond plus an (aqua)O-H···O6(acv) interligand interaction; and (c) trans-apical/distal sites are occupied by monodentate O-sulfate donor anions. Neutral acyclovir and aqua-proximal ligands occupy the basal positions, stabilizing the metal binding pattern of acv. Each hydronium(1+) ion builds three H-bonds with O-sulfate, O6(acv), and O-alcohol(acv) from three neighboring complex anions. No O atoms of solvent water molecules are involved as acceptors. Theoretical calculations of molecular electrostatic potential surfaces and atomic charges also support that the O-alcohol of the N9(acv) side chain is a better H-acceptor than the N3 or the O-ether atoms of acv. [ABSTRACT FROM AUTHOR]

A new coordination network, namely [Cd(pda)(IP)(H2O)] (1) (H2pda = pyrazine-2,3-dicarboxylic acid and IP= 1-H-imidazo[4,5-f][1,10]-phenanthroline), is explored. A 2D supramolecular net is formed by the hydrogen bonding interactions between IP and coordination water molecule and between carboxylate ligand and water molecule. The luminescence study indicates that the title compound emits bright fluorescence. [ABSTRACT FROM AUTHOR]

The mixed-ligand complexes of Ru(phen)2Cl2.2H2O and Ru(bipy)2Cl2.2H2O with 2,6-diacetylpyridinedihydrazone were prepared and characterized using elemental analyses and spectroscopic techniques. Semi-empirical (PM3) andab initio (HF/3-21G*) methods were used for the calculations of geometries, heat of formation, binding and stabilization energies. The elemental analyses were satisfactory when compared with the calculated values. The infrared and UV-Vis spectra as well as the fragmentation patterns in the mass spectra were consistent with octahedral Ru(II) complex. The conductivity measurements confirmed the 1:2 electrolyte nature of the complexes. The theoretical studies revealed higher stabilization and binding energies for the [Ru(phen)2L]2+species which indicated that it is thermodynamically more stable. [ABSTRACT FROM PUBLISHER]

Solvothermal reaction of pyrazole-3-carboxylic acid (H 2 pac) and different d 10 metal salt with or without auxiliary organic ligand afforded three new coordination compounds: [Cd(Hpac)(H 2 O)Cl] n ( 1 ), [Cd(Hpac)(phen) 2 ]ClO 4 ( 2 , phen = 1,10-phenanthroline) and [Zn(pac)(2,2′-bipy)(H 2 O)] 2 ·2H 2 O ( 3 , 2,2′-bipy = 2,2′-bipyridine). Compounds 1 – 3 all feature mixed-ligand characteristic. 1 consists of a two-dimensional (2-D) layer structure containing (4,4) networks. 2 is composed of a mononuclear [Cd(Hpac)(phen) 2 ] + cation and a perchlorate anion. 3 contains a binuclear [Zn(pac)(2,2′-bipy)(H 2 O)] 2 cluster and water molecules. Through abundant hydrogen bonds and/or offset π⋯π stacking interactions, the molecules of 2 and 3 assemble into 2-D and 3-D supramolecular frameworks, respectively. The Hpac − or pac 2− ligands in 1 – 3 display three different coordination modes. Photoluminescence studies in the solid state reveal that 1 – 3 exhibit interesting luminescent behaviors, and the relevant density of states (DOS) calculation results show that their photoluminescence mainly originates from the Hpac − ligand-centered charge transition mixing with Cl − –Hpac − charge transition for 1 , mixed organic ligand–organic ligand charge transition and ClO 4 − –phen charge transition for 2 , and mixed organic ligand–organic ligand charge transition for 3 . [ABSTRACT FROM AUTHOR]

The structural and magnetic properties of two novel one-dimensional coordination compounds were investigated in the solid crystalline state to support studies of their potential as multifunctional materials. The new compounds are based on Co(II) and are named {[Co 4 (glu) 4 (phen) 4 (H 2 O) 2 ]·H 2 O} n (1) and {[Co 2 (azl) 2 (phen) 2 (H 2 O) 2 ]} n (2) (glu = glutarate, azl = azelate, and phen = 1,10-phenanthroline). Compound (2) is the first crystal structure of a cobalt-based coordination polymer with the mixed ligands azl and phen. The crystal structures of the compounds were determined by single crystal X-ray diffraction; where the influence of the alkyl dicarboxylates on the formation of a 1D looped or a single chain coordination polymer was observed. The FT-IR analysis confirms the coordination modes adopted by the mixed ligands azl and phen and the thermal analysis suggests some thermal stability up to 150-200 °C. Supramolecular analysis suggests an important role of the non-conventional C(sp2)-H···O hydrogen bond patterns in the crystals. Finally, weak antiferromagnetic interactions were observed in both complexes. • Reactions of Co(II) ions with 1,10-phenanthroline and alkyl dicarboxylates (glutaric and azelaic acids) were performed. • Two novel 1-D coordination polymers were obtained, including an unprecedented cobalt-based coordination polymer with mixed ligands azelate and 1,10-phenantroline). • Both coordination compounds exhibit weak antiferromagnetic interactions. Two new coordination polymers {[Co 4 (glu) 4 (phen) 4 (H 2 O) 2 ]·H 2 O} n (1) and {[Co 2 (azl) 2 (fen) 2 (H 2 O) 2 ]} n (2) were synthesized. Magnetic studies revealed weak antiferromagnetic interactions between the Co(II) ions. [Display omitted] [ABSTRACT FROM AUTHOR]

The design and construction of metal organic frameworks (MOFs) or coordination polymers (CPs) with tunable structures is of great interest in recent years, owing to their intriguing structural diversity and potential applications. The mixed-ligand approach is widely used as an effective synthesis method to fabricate CPs. By precise regulation of the structure of N-donor co-ligands, in this work, a series of zinc/cadmium-organic arsonates are successfully synthesized, namely, [Zn 2 (OH)(L-As)(4,4′-Bipy)⋅H 2 O] n (1), [Zn 3 (L-As) 2 (2,2′-Bipy)(H 2 O) 2 ⋅2H 2 O] n (2), [Cd(HL-As)(4,4′-Bipy) 0.5 ] n (3), [Cd(HL-As)(2,2′-Bipy)(H 2 O)⋅H 2 O] n (4) (H 3 L-As ​= ​2-(carboxymethylamino)phenylarsonic acid; 4,4′-Bipy ​= ​4,4′-bipyridine; 2,2′-Bipy ​= ​2,2′-bipyridine). We demonstrate that N-donor co-ligands significantly affect the coordination environment of metal centers and the structure of these compounds. Compound 1 is a three-dimension (3D) hydrogen-bond network via C–H···π interactions between the aromatic rings of L-As ligand, whereas 3 exhibits a 3D framework with 6-connected pcu topological network. By contrast, 2 and 4 are two-dimension (2D) layered structures by adopting chelated 2,2′-Bipy Co-ligand. All compounds display a luminescence from ligand-to-metal charge transfer (LMCT) which depends on the coordination environment of metal centers. The results show that N-donor co-ligands can effectively regulate the structures and luminescent properties of the formed CPs. A series of zinc/cadmium-organic arsonates is successfully synthesized by adopting a mixed-ligand approach with H 3 L-As as the main ligand and 4,4′-bipyridine (4,4′-Bipy) or 2,2′-bipyridine (2,2′-Bipy) as N-Donor co-ligands. The introduction of N-Donor co-ligand affects the coordination modes of H 3 L-As ligand and Zn(II)/Cd(II) ion center and regulates the luminescent properties of the resultant compounds. [Display omitted] • A series of zinc/cadmium-organic arsonates are successfully synthesized by mixed-ligand approach. • N-donor co-ligands significantly affect the coordination environment of metal centers and the structure of these compounds. • Four compounds show different fluorescence properties. [ABSTRACT FROM AUTHOR]

In this study, we report the adsorption removal of indomethacin sodium (IDM) by the mixed-linker Materials of Institute Lavoisier (MIL)-101(Cr)s. The MIL-101(Cr)s were synthesized by controlling the ratios of 1,4-benzene dicarboxylic acid (H 2 BDC) and 2-amino-1,4-benzene dicarboxylic acid (NH 2 –H 2 BDC). Then their adsorption performances toward IDM were investigated. Due to the increase in specific surface area and the contribution of enhanced multiple action mechanisms, MIL-101(20) was proved to have the optimal IDM absorption among all the mixed-ligand MIL-101(Cr)s. The adsorption kinetic data was found to accord with the pseudo-second-order kinetic model, and the rate constant (k 2) was calculated as 0.0059 ​g ​mg−1 ​min−1. The selected MIL-101(20) exhibited the maximum IDM adsorption capacity of approximately 641 ​mg ​g−1 (318 ​K), calculated from the Langmuir linear plots. The simulation results of the thermodynamic model suggest that the adsorption could be a spontaneous, endothermic process with increasing randomness. The adsorption mechanism analysis indicates that the synergistic effects of electrostatic interaction, hydrogen bond interaction, and π-π stacking could be responsible for efficient IDM adsorption. In addition, the adsorbent also presented good reproducibility over six successive adsorption/desorption cycles. Therefore, the mixed-ligand MIL-101(Cr) could be recommended as a promising adsorbent for the preferential removal of IDM from polluted wastewater. IDM removal on mixed-linker MIL-101(Cr). [Display omitted] • The surface area and chemical properties of MIL-101(Cr)s ​were regulated by the ligand ratios. • The rapid removal of indomethacin sodium (IDM) by mixed-linker MIL-101(Cr) was achieved. • MIL-101(20) (introduction of 20% NH 2 –H 2 BDC) exhibited high efficiency in the selective adsorption of IDM. • The electrostatic interaction, H-bond interaction, and π-π stacking were suggested as possible adsorption mechanisms. [ABSTRACT FROM AUTHOR]

Three new mixed-ligand Schiff base complexes with N -donor co-ligands were synthesized and characterized. Molecular docking and pharmacophore modeling were performed on main proteases of SARS-CoV-2 virus. [Display omitted] Three new mixed-ligand copper(II) complexes (1 – 3) with NN'O type unsymmetrical tridentate Schiff base ligands (SB) and N -donor heterocyclic co-ligands, with general formula [Cu(SB)(L)]ClO 4 , were synthesized and characterized using single crystal x-ray diffraction (SCXRD), FT-IR and UV–Vis spectroscopy and elemental analyses. The SB ligand is the half-unit form of the condensation of 1,3-propanediamine with 5-methoxysalicylaldehyde and the co-ligands (L) are pyridine (py in (1)), 2,2′-bipyridine (bpy in (2)) and 1,10-phenanthroline (phen in (3)). Crystal structures of (2) and (3) were obtained by SCXRD. Molecular docking and pharmacophore studies were performed to study the interactions between the synthesized complexes and SARS-CoV-2 virus main proteases (PDB IDs: 6LU7, 6WQF and 6W9C). Results revealed that complex (3) with phen co-ligand showed better docking scores with the three receptors, i.e. 6LU7 (−8.05 kcal.mol−1), 6W9C (−7.70 kcal.mol−1) and 6WQF (−7.75 kcal.mol−1). The order of the binding best energies for (3) was also as follows: 6LU7 > 6WQF > 6W9C. All of the studied complexes showed considerable performance, comparable to the standard drug, Favipiravir. [ABSTRACT FROM AUTHOR]

The hydronium salt (H3O)2[Cu(N7–acv)2(H2O)2(SO4)2]·2H2O (1, acv = acyclovir) has been synthesized and characterized by single-crystal X-ray diffraction and spectral methods. Solvated Cu(OH)2 is a by-product of the synthesis. In the all-trans centrosymmetric complex anion, (a) the Cu(II) atom exhibits an elongated octahedral coordination; (b) the metal-binding pattern of acyclovir (acv) consists of a Cu–N7(acv) bond plus an (aqua)O–H···O6(acv) interligand interaction; and (c) trans-apical/distal sites are occupied by monodentate O-sulfate donor anions. Neutral acyclovir and aqua-proximal ligands occupy the basal positions, stabilizing the metal binding pattern of acv. Each hydronium(1+) ion builds three H-bonds with O–sulfate, O6(acv), and O–alcohol(acv) from three neighboring complex anions. No O atoms of solvent water molecules are involved as acceptors. Theoretical calculations of molecular electrostatic potential surfaces and atomic charges also support that the O-alcohol of the N9(acv) side chain is a better H-acceptor than the N3 or the O-ether atoms of acv.

Five imidazole/benzimidazole-based metal complexes, Cd(bim)2(L1)2 ( 1) [L1 = 2-methyl-2-phenoxypropionate, bim = benzimidazole], Zn(im)2(L2)2 ( 2) [L2 = 3-(4-methoxyphenyl)acrylate, im = imidazole], Zn(im)2(L3)2 ( 3) [L3 = 3,4-(methylenedioxy)benzoate], [Cd(im)2(L3)2]2 ·4H2O ( 4), and Cd(Bim)2(L4) ·CH3CH2OH ·H2O ( 5) (L4 = 1,4-cyclohexanedicarboxylate), were obtained by the introduction of the carboxylates as coligands and are structurally characterized by different techniques including elemental analysis, IR spectra, TG, and single-crystal X-ray diffraction analysis. The X-ray crystal structure analyses reveal that these complexes display mononuclear to dinuclear structures with tetrahedral coordination spheres around each central zinc atom, and octahedral coordination sphere around each central cadmium atom. The imidazole ligands in all compounds are coordinated only in a monodentate fashion with their neutral nitrogen groups. The carboxylates coordinate to the metal in monodentate, chelating bidentate, and bridging bidentate fashions. The N-H ···O hydrogen bonds from the NH donor of the neutral imidazole were found in all compounds. On the basis of X-ray crystallographic study the rich intra- and intermolecular noncovalent interactions (including classical hydrogen bonds, C-H ···O, CH2 ···O, CH3 ···O, CH2-N, C-H ···π, CH3-π, O-H ···π, and π-π interactions) are analyzed. The various nonbonding interactions in these compounds are responsible for different structures such as 3D network, 3D prismatic layer network, and 3D layer network structure. [ABSTRACT FROM AUTHOR]

A new three-dimensional (3D) POMOF based on α-metatungstate and mixed-ligand, [Cu4(pzta)2(bipy)4(H2O)6][H2W12O40]·2H2O (1) (pzta=5-(2-pyrazinyl) tetrazole, bipy=4,4′-bipyridine), has been synthesized and characterized by routine methods. In 1, there is a 2D inorganic layer constructed by W12 clusters and copper cations, which is reinforced by the incorporation of the dinuclear copper complexes to form a poly-pendant layer. Furthermore, the dicoordinated bipy ligands as pillars link parallel neighboring poly-pendant layers to generate a novel 3D framework with a (65 ·81)2(67 ·87 ·121) topology. To the best of our knowledge, it represents the first 3D POMOF constructed by α-metatungstate and mixed-ligand. In addition, the electrochemical studies show that 1 has a good electrocatalytic activity toward reduction of nitrite. [ABSTRACT FROM AUTHOR]

Highlights: [•] A new Cu coordination polymer with mixed-ligands has been synthesized. [•] The 3D framework was proved by single-crystal X-ray diffraction. [•] Title compound is an unprecedented 3,5-connected ‘ fet’ topological network. [ABSTRACT FROM AUTHOR]

Highlights: [•] Structural chemistry of 93 fluoride and 34 mixed-ligand fluoride Zr and Hf complexes are reviewed. [•] The structures show systematic variations with the F(L):Zr(Hf) ratio and CN of the metal ion. [•] Common coordination polyhedra include octahedron, pentagonal bipyramid and dodecahedron. [ABSTRACT FROM AUTHOR]

Abstract: Six trinuclear substituted complexes of the type Ru3(CO)9(arphos)(L) were synthesized by a substitution reaction involving Ru3(CO)10(arphos) (1) with L, where L=PCy3, PPh3, P(C6H4F-m)3, P(C6H4F-p)3, P(C6H4Cl-p)3 and PPh(C6H4OMe-p)2, using a thermal method. The structures of the resulting clusters were elucidated by single crystal X-ray diffraction, complemented by means of elemental analysis and spectroscopic methods, including infrared spectroscopy and 1H, 13C{1H} and 31P{1H} NMR spectroscopy. The longest Ru–Ru bond in Ru3(CO)9(arphos)(L) [L=PCy3 (2), P(C6H4F-m)3 (4), P(C6H4F-p)3 (5), P(C6H4Cl-p)3 (6) and PPh(C6H4OMe-p)2 (7)] is the bond that is cis to the monodentate phosphine ligands, while in Ru3(CO)9(arphos)PPh3 (3), the longest bond is the bond that is bridged by the arphos ligand. [Copyright &y& Elsevier]

Abstract: A new 3D coordination polymer, Mn2(atz)(isonic)(OH)(Cl)]n (1), was synthesized hydrothermally from mixed-ligands of Hatz (Hatz=5-amino-tetrazolate) and Hisonic (Hisonic=isonicotinate) and corresponding metal salts. It was characterized by IR spectra, elemental and thermal analysis, single crystal and powder X-ray diffraction. Variable temperature magnetic investigations indicate that compound 1 exhibits typical antiferromagnetic behaviors. [Copyright &y& Elsevier]

Under similar hydrothermal synthetic conditions using a novel flexible ligand 2-(3-(pyridin-2-yl)-1H-pyrazol-1-yl)acetonitrile (PPAN), benzenedicarboxylate isomers (H2pa=phthalate, H2ip=isophthalate, and H2tp=terephthalate) and Cadmium(II) acetate, three novel mixed-ligand Cd(II) coordination polymers {[Cd2(PPAA)2(μ-pa)(H2O)]·2H2O} n (1), {[Cd4(PPAA)4 (μ4-ip)2]·2H2O} n (2) and {[Cd2(PPAA)2(μ-tp)]·2H2O} n (3) (PPAA− =2-(3-(pyridin-2-yl)-1H-pyrazol-1-yl) acetate) have been isolated, in 1–3 PPAN, and are also hydrolyzed into a novel PPAA− ligand. Complex 1 is a 1D coordination polymer in which the tetra-nuclear [Cd4(PPAA)4]4+ structural units are extended by tri-dentate μ-pa2− ligands. Complex 2 contains binuclear [Cd2(PPAA)2]4+ structural units, which are extended by four tetra-dentate μ4-ip2− ligands to link eight neighboring binuclear [Cd2(PPAA)2]4+ units ultimately forming a 2D layered framework, while complex 3 contains 1D double chain containing [Cd(PPAA)] n cation structural units, which are further extended by tetradentate μ-tp2− ligands to form a new 2D layered framework. All the complexes have been investigated by elemental analysis, FT-IR, thermal analysis and fluorescence characterization. The flexible coordination modes of PPAA− are also briefly analyzed. The flexible coordination modes of PPAA− and benzenedicarboxylate isomers also reveal great potential in the construction of these novel mixed-ligand luminescent frameworks with diverse structural motifs and unique functional properties. [ABSTRACT FROM AUTHOR]

Two novel, mixed ligand complexes of cobalt(III) and nickel(II), [Co(phen)(taptp)] ( 1) and [Ni(phen)(taptp)] ( 2) (phen = 1,10-phenanthroline and taptp = 4,5,9,18-tetraazaphenanthreno [9,10-b]triphenylene), were synthesized and characterized by elemental analyses, UV-visible and NMR spectroscopies. The binding interactions of the two complexes with DNA have been investigated using absorption and emission spectroscopy methods and electrophoresis measurement mode. The intrinsic binding constants for these complexes to DNA are in the order of 10. In Tris buffer, the Co(III) complex shows a moderate luminescence which was enhanced after binding to DNA. However for complex Ni(II), no emission was observed in Tris buffer. The [Co(phen)(taptp)] and [Ni(phen)(taptp)] can cause the photocleavage of DNA supercoiled pBR322 upon irradiation by 360 nm light. Based on the data, an intercalative mode of DNA binding is suggested for the two complexes. [ABSTRACT FROM AUTHOR]

Abstract: Two Zn(II) and Cd(II) compounds with the in-situ generated ligand of 5-amino-tetrazolate (atz−) were prepared from the hydrothermal reactions of the corresponding Cd or Zn(II) salts with phenylcarboxylate, and characterized by elemental analysis, IR spectroscopy, and TGA. The results of X-ray crystallographic analysis reveal that compound [Zn2(BZA)(atz)2(OH)] n (1) (BZA=benzoic acid) presents a two-dimensional (2D) “hcb” topological network constructed from the ZnN2O2 tetrahedra. In compound [Cd6(atz)6(PTA)3] n (2) (PTA=terephthalic acid), the identical [Cd3(atz)3)]3+ n clusters are connected by atz ligands to generate a 2D cationic layer, and the neighboring cationic layers are pillared by PTA giving birth to 3D network. After simplifying, the complicated 3D network of 2 can be presented as an unprecedented (4, 4, 10)-connected trinodal topology. The formations of the structures show a good example that using the combination of the in-situ generated ligand and other coligand synthetic strategy can construct interesting topological structures. The thermal stabilities and fluorescent properties of the complexes have also been studied. [Copyright &y& Elsevier]

Lanthanum(III) and cerium(III) complexes of pyridine-2,6-dicaboxylic acid (HPydc) have been prepared and their crystal structures were determined by X-ray crystallography. The single crystal analysis reveals that the lanthanum(III) complex, 1 is polymeric consisting of {[La(Pydc)(HO)]·4HO} units linked through carboxylate oxygen atoms and exhibiting nine coordination number. Intermolecular O-H···O hydrogen bonds produce R(6), R(16) and R(20) rings, which lead to three-dimensional polymeric chains. The crystal structure of the cerium(III) complex, 2 [{Ce(Pydc)}{Ce(Pydc)(HO-CHCH-OH)(HO)}·6HO)] shows that the complex is a mixed-ligand binuclear system in which one cerium coordinated to three Pydc molecules, while the other cerium is bound to one Pydc, one oxygen atom of the other Pydc, one ethylene glycol and three water molecules. Each of the two Ce(III) ions is nine coordinated. Intermolecular O-H···O hydrogen bonds produce R(8) and R(20) rings, which lead to three-dimensional polymeric chains. The complexes were further investigated using elemental analysis, FTIR spectroscopy and thermogravimetric analysis. [ABSTRACT FROM AUTHOR]

The Cu(II) complexes, [Cu(2,5-pydc)(bmi)(H2O)]n, [Cu2(H2O)2(2,6-pydc)2(btx)]·2H2O and [Cu(btc)2(bmi)2]·1.5H2O, (bmi = 1-[(benzotriazol-yl)methyl)-1H-1,3-imidazole; 2,5-H2pydc = pyridine-2,5-dicarboxylic acid; btx = 1,4-bis(1,2,4-triazol-1ylmethyl)benzene; H3btc = 1,3,5-benzenetricarboxylate) have been synthesised and their X-ray structures show that hydrogen bonds and π···π stacking interactions are employed in their construction. The complexes can effectively catalyse the oxidative coupling reaction of 2,6-di-tert-butylphenol in good yield and unique selectivity. [ABSTRACT FROM AUTHOR]

Some mononuclear mixed-carboxylato β-diketonato oxovanadium(IV) complexes of the general formula [VO(β-dike)(RCOO)] (where Hβ-dike = acetylacetone; benzoylacetone or dibenzoylmethane, R = CH or CH) have been synthesized from VO(acac) by stepwise substitutions of acetylacetonate ion with straight chain fatty acids (RCOOH) and β-diketones in p-xylene under reflux. The substituted acetylacetone could be fractionated out with p-xylene as an azeotrope. These were characterized by elemental analyses, molecular weight determinations, spectral (electronic, infrared, H NMR, EPR and powder XRD) studies, magnetic susceptibility measurements and cyclic voltammetry. Molar conductance values indicated the complexes to be non-electrolytes in nitrobenzene. Bidentate chelating nature of β-diketonate and carboxylate ligands in the complexes was established by infrared and NMR spectra. Molecular weight determinations confirmed mononuclear nature of the complexes. The EPR spectra illustrated coupling of the unpaired electron with V nucleus ( I = 7/2). Cyclic voltammograms of all the complexes displayed one-step oxidation processes. The oxidation peak potential corresponded to the quasireversible one-electron oxidation process of the metal center, yielding V(V) species. Powder XRD and transmission electron microscopy (TEM) studies indicated the particles of these were lying in the nano-size range. The synthesized complexes are a new type of mixed-ligand complexes in which vanadium is having coordination number 5. A square pyramidal geometry around vanadium has been assigned in all the complexes. [ABSTRACT FROM AUTHOR]

Abstract: A new series of luminescent mononuclear Cu(I) heteroleptic complexes of 6-cyano-2,2′-bipyridine (cbpy), [Cu(cbpy)(PPh3)X] (X=I (1); Br (2)) and [Cu(cbpy)(PPh3)2](ClO4) (3), has been synthesized and characterized. It is revealed that phosphine in place of halide results in lengthening of the Cuom 2.21Å of 1 and 2.19Å of 2 to 2.27Å of 3. Complexes 1–3 display the weak low-energy absorption bands in the 350–600nm region in dichloromethane, which are assigned to the Cu(I) to cbpy metal-to-ligand charge-transfer (MLCT) transitions, probably mixed with some halide-to-ligand charge-transfer (XLCT) character for 1 and 2. Complexes 1–3 show the solid-state emissions at ambient temperature, varying with the second auxiliary ligand coordinated to the {Cu(cbpy)(PPh3)} motif, which most likely originate from the MLCT excited states, perhaps involving some XLCT character for 1 and 2. [Copyright &y& Elsevier]

Abstract: Two 2-(2-benzimidazolyl)-6-methylpyridine (Hbmp) copper(I) complexes bearing PPh3 and 1,4-bis(diphenylphosphino)butane (dppb), namely, [Cu(Hbmp)(PPh3)2](ClO4) (1) and [Cu(Hbmp)(dppb)](ClO4) (2), have been synthesized. X-ray diffraction analysis reveals that the most significant influence of the phosphine ligands on the structures is on the P–Cu–P bond angle. Both two Cu(I) complexes exhibit a weak low-energy absorption at 360–450nm, ascribed to the Cu(I) to Hbmp metal-to-ligand charge-transfer (MLCT) transition, perhaps mixed with some ILCT character inside Hbmp. The room-temperature luminescences are observed for 1 and 2, both in solution and in the solid state, which originate from the MLCT excited states and vary markedly with the phosphine ligands. [Copyright &y& Elsevier]

Abstract: A new mixed-ligand copper pentaborate, [Cu(en)2(C5H9NO)][B5O6(OH)4]2·C5H9NO (en is ethylenediamine) (1), with novel framework has been synthesized under mild solvothermal condition and characterized by FT-IR, elemental analyses, powder X-ray diffraction and TG–DTA. The structure consists of isolated polyborate anion [B5O6(OH)4]−, copper complex cation [Cu(en)2(C5H9NO)]+ and one C5H9NO molecule. The [B5O6(OH)4]− units are connected to one another through hydrogen bonds to form an interesting three-dimensional (3D) supramolecular framework with alternate square-like channels and rectangle-like channels along the c-axis as well as ellipse-like channels with 16-membered boron rings along the a-axis which are the largest channels in the pentaborate reported so far. The copper complex cation contains two kinds of ligands, en and C5H9NO, forming a square pyramid with an O atom as the vertex. [Copyright &y& Elsevier]

The title compound (CMe)U(OBu)(SePh) ( 1) was synthesized and characterized by NMR spectroscopy, elemental analysis, and X-ray crystallography. This system represents a unique example of an actinide complex with two different group 16 elements coordinated to the metal center and the first mixed-ligand actinide alkoxide-selenide complex. The complex crystallizes in the orthorhombic space group Pbca with unit cell parameters a = 17.830(7) Å, b = 14.973(6) Å, c = 21.254(8) Å, V = 5674(4) Å, Z = 8, D = 1.727 Mg/m. The uranium(IV) mixed-ligand alkoxide-selenide complex adopts a pseudo-tetrahedral geometry, with the tert-butoxide and phenylselenide ligands occupying the plane bisecting the metallocene unit. Structural comparisons of the complex (CMe)U(OBu)(SePh) ( 1) are made with related selenide and alkoxide uranium(IV) complexes. Graphical Abstract: Reaction of (CMe)U(OBu) with MeSi-SePh affords the unusual alkoxide-selenide uranium(IV) complex (CMe)U(OBu)(SePh), which has been characterized by a combination of NMR spectroscopy, elemental analysis, and X-ray crystallography. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

A new mixed-ligand linear tetranuclear copper(II) complex [Cu4(2,2'-bpy)6(ip)2(H2O)2]·4ClO4·6H2O (1) (2,2'-bpy = 2,2'-bipyridine, H2ip = isophthalic acid) has been obtained, which crystallizes in the monoclinic space group C2/c, with a = 24.130(6)Å, b = 15.344(4) Å, c = 24.923(6) Å, and β = 102.532(5)°. The tetranuclear structure of 1 may be described as one central dimeric [Cu2(2,2'-bpy)2(ip)2(H2O)2] unit and two terminal [Cu(2,2'-bpy)2] units linked by two bridging ip ligands. The tetranuclear entity, perchlorate anions, and lattice water molecules are further linked by extensive hydrogen bonds to form a three-dimensional (3D) supramolecular structure. The magnetic susceptibility of 1 has been investigated at 2-300 K and the fit of the magnetic data indicates that 1 exhibits anti-ferromagnetic exchange with J = -107 and J' = -13 cm-1. [ABSTRACT FROM AUTHOR]

Abstract: Reaction of the trivalent uranium complex (C5Me5)2U(O-2,6- i Pr2C6H3)(THF) (1) with copper(I) chloride affords the corresponding tetravalent mixed-ligand aryloxide–chloride complex (C5Me5)2U(O-2,6- i Pr2C6H3)(Cl) (2). The oxidative functionalization protocol cannot be extended to the synthesis of (C5Me5)2U(O– t Bu)(Cl) (3) since the corresponding trivalent precursor is not stable. Salt metathesis between (C5Me5)2UCl2 and KO t Bu is the method of choice for the preparation of the tetravalent alkoxide–chloride derivative (C5Me5)2U(O– t Bu)(Cl) (3). The X-ray crystal structures of (C5Me5)2U(O-2,6- i Pr2C6H3)(Cl) (2) and (C5Me5)2U(O– t Bu)(Cl) (3) are reported and represent the first structurally characterized uranium(IV) metallocene aryloxide–chloride and alkoxide–chloride complexes, respectively. Both complexes adopt a pseudo-tetrahedral geometry, with a chloride and aryloxide/alkoxide ligand occupying the plane bisecting the metallocene unit. [Copyright &y& Elsevier]

Abstract: A nano-sized mixed-ligand Cd(II) coordination polymer, {[Cd(bpa)(4,4′-bipy)2(H2O)2](ClO4)2} n (1); bpa=trans-1,2-bis(4-pyridyl)ethane and 4,4′-bipy=4,4′-bipyridine, has been synthesized by a sonochemical method and characterized by IR and 1H NMR spectroscopy. Compound 1 grows in one dimension by two different bridging ligands, 4,4′-bipy and bpa. The thermal stability of compound 1 in the bulk form and nano-sized was studied by thermogravimetric (TG) and differential thermal analysis (DTA). The crystallinity of this compound was studied by X-ray powder diffraction and compared with an XRD simulation of the single crystal data. CdO nanoparticles were obtained by direct calcination at 500°C and decomposition in oleic acid at 200°C of the nano-sized compound 1. The obtained cadmium(II) oxide nano-particles were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). [Copyright &y& Elsevier]

Four benzimidazole (bim)-based metal complexes, {[Zn2(bim)4(btec)] · DMF}n (1), {[Zn(bim)(btc)] · Htea}n (2), [Zn(bim)2(bdc)]n (3), and {[Cd3(bim)4(H2O)6(btc)2] ⋅ 2H2O}n (4) (H4btec = 1,2,4,5-benzenetetracarboxylic acid, H3btc = 1,3,5-benzenetricarboxylic acid, H2bdc = 1,4-benzenedicarboxylic acid, and tea = triethylamine), have been obtained by the introduction of benzene-based polycarboxylate as coligand and are structurally characterized by single-crystal X-ray diffraction, elemental analysis, IR spectra, thermogravimetric curves, and luminescence spectra. Controlled by the number and position of the carboxylates attached to the aromatic ring, all the four complexes exhibit polymeric structures from 1-D chain or ribbon for 1, 3, and 4 to 2-D layer for 2. In contrast, the neutral bim is a terminal ligand to complete the metal coordination sphere and it also helps to assemble the low-dimensional coordination skeleton into a high-dimensional ordered supramolecular architecture by N-H ··· O hydrogen-bonding and π-π stacking interactions. Additionally, the complexes exhibit strong emissions originating from the bim-based intraligand as well as photo-induced interligand charge transfer upon cation binding, suggesting potential applications as luminescent materials. [ABSTRACT FROM AUTHOR]

Abstract: A series of binary complexes of iron(III), cobalt(II), nickel(II), copper(II), zinc(II), cerium(III) and uranyl(VI), have been synthesized by using the organic ligand, H3L, formed by the condensation of thiocarbohydrazide with 2-hydroxy-1-naphthaldehyde. Also, ternary complexes were synthesized by using 1,10-phenanthroline or oxalic acid as a secondary ligand. Characterization and structure elucidation of the synthesized compounds were achieved by elemental and thermal analyses, spectral (IR, electronic, ESR and 1H and 13C NMR), molar conductivities as well as magnetic measurements. The spectroscopic data showed that the ligand acts as a neutral, monobasic or dibasic tetradentate ligand. All the metal complexes exhibited octahedral geometry except cerium(III) and uranyl(VI) complexes in which the metal ions are hepta- and octa-coordinated. The ligand and some metal complexes showed antibacterial activity towards Staphylococcus aureus and Escherichia coli bacteria and antifungal activity towards the fungi Candida albicans and Aspergillus flavus. [ABSTRACT FROM AUTHOR]

Abstract: Two novel mixed-ligand dicopper(I) halide complexes, [{Cu(PPh3)X}2(μ-HL)] (HL=3,5-bis{6-(2,2′-dipyridyl)}pyrazole, X=I (1); Br (2)), have been synthesized by a straightforward double-layer diffusion approach and structurally characterized by single-crystal X-ray diffraction. The multi-site HL acts as a bridging bis-bidentate chelate, assembling two Cu(PPh3)X moieties into copper(I) dimers possessing the triple-decker “organic” sandwich structure of phenyl/pyrazolyl/phenyl through π···π interactions. Complexes 1 and 2 exhibit photoluminescence in the solid state at ambient temperature, ascribed to a combination of intraligand charge transfer (ILCT) and metal-to-ligand charge transfer (MLCT) transitions. The emission of 2 is red-shifted 18nm relative to that of 1 due to substitution of the iodides of 1 by the weaker electron-donating bromides. [Copyright &y& Elsevier]

Abstract: A new coordination polymer, [Cd4(atz)6(PTA)] n has been firstly synthesized by employing mixed-ligand of terephthalic acid (PTA) with the in-situ generated ligand of 5-amino-tetrazolate (atz−). Compound 1 represents a 3D microporous framework constructed from Cd-tetrazolate subunits and the subunits are bridged by PTA and atz ligands. When the subunit was collided into node, compound 1 possesses an unprecedented 3, 9-connected topological network. Furthermore, the investigations of thermal stability and luminescent property of complex 1 indicate that compound 1 may be an excellent candidate for potential blue-light emitting material. [Copyright &y& Elsevier]

Abstract: A series of uranium(IV) mixed-ligand amide–halide/pseudohalide complexes (C5Me5)2U[N(SiMe3)2](X) (X=F (1), Cl (2), Br (3), I (4), N3 (5), NCO (6)), (C5Me5)2U(NPh2)(X) (X=Cl (7), N3 (8)), and (C5Me5)2U[N(Ph)(SiMe3)](X) (X=Cl (9), N3 (10)) have been prepared by one electron oxidation of the corresponding uranium(III) amide precursors using either copper halides, silver isocyanate, or triphenylphosphine gold(I)azide. Agostic U⋯H–C interactions and η3-(N,C,C′) coordination are observed for these complexes in both the solid-state and solution. There is a linear correlation between the chemical shift values of the C5Me5 ligand protons in the 1H NMR spectra and the UIV/UIII reduction potentials of the (C5Me5)2U[N(SiMe3)2](X) complexes, suggesting that there is a common origin, that is overall σ-/π-donation from the ancillary (X) ligand to the metal, contributing to both observables. Optical spectroscopy of the series of complexes 1–6 is dominated by the (C5Me5)2U[N(SiMe3)2] core, with small variations derived from the identity of the halide/pseudohalide. The considerable π-donating ability of the fluoride ligand is reflected in both the electrochemistry and UV-visible-NIR spectroscopic behavior of the fluoride complex (C5Me5)2U[N(SiMe3)2](F) (1). The syntheses of the new trivalent uranium amide complex, (C5Me5)2U[N(Ph)(SiMe3)](THF), and the two new weakly-coordinating electrolytes, [Pr4N][B{3,5-(CF3)2C6H3}4] and [Pr4N][B(C6F5)4], are also reported. [Copyright &y& Elsevier]

A 2-D coordination polymer with mixed ligands, [Zn2(BDC)(4,4'-bipy) (HCOO)2] (1) (BDC, 1,4-benzenedicarboxylate; 4,4'-bipy, 4,4'-bipyridine), has been synthesized by solvothermal reaction. Compound 1 provides the first coordination polymer structure constructed by bridging BDC, 4,4'-bipy, and formate. Both BDC and 4,4'-bipy link zincs alternatively, resulting in a zigzag coordination chain; adjacent chains are further linked by formates to form an infinite extended 2-D folding screen layer. The synthesis mechanism and fluorescence property are discussed. [ABSTRACT FROM AUTHOR]

Four 1,3-bis(1,2,4-triazol-1-yl)propane (btp)-based transition metal complexes, {[Zn(btp)3] ⋅(ClO4)2}n (1), [Zn(btp)2(dca)2]n (2), [Zn(btp)(NCS)2] (3), and [Mn(btp)2(NCS)2]n (4), have been obtained by introducing small anionic coligands and structurally characterized by single crystal X-ray diffraction, elemental analysis, IR spectra, thermogravimetric curves, and solid luminescence spectra. Structural determinations reveal that the polymeric triple-stranded chain for 1 without coligand is changed into 1-D double-stranded chains for 2 and 4, and discrete binuclear structure for 3. Compared with 1, the mixed-ligand complexes are moderately destabilized for 2 and 4, and slightly enhanced for 3. Additionally, the four solid complexes exhibit strong emissions, suggesting their potential applications as luminescent materials. [ABSTRACT FROM AUTHOR]

Abstract: In order to deepen our understanding of the versatile behaviour of adenine (Hade) as ligand, we have synthesized four novel ternary copper(II) complexes having two deazaadenine ligands, namely 4-azabenzimidazole (H4abim) or 7-azaindole (H7azain) as N1,N6-dideazaadenine or N1,N6,N7-trideazaadenine, respectively. The related compounds were studied by thermal, spectral and single crystal X-ray diffraction methods. In [Cu(NBzIDA)(H4abim)] n (1) the recognition between H4abim and the (N-benzyliminodiacetate)-copper(II) chelate only displays the formation of the Cu–N7(purine-like) bond, in contrast to Hade behaviour in [Cu(NBzIDA-like)(Hade)(H2O)]·H2O (Cu–N3(Hade) bond reinforced by N9–H···O(IDA-like) interaction). In [Cu(EIDA)(H7azain)(H2O)] (2, EIDA= N-ethyliminodiacetate ligand), [Cu(NBzIDA)(H7azain)(H2O)] (3) and [Cu(μ2-SO4)(H7azain)2(H2O)2] n (4), H7azain binds Cu(II) centre by the Cu–N3(purine-like) bond, reinforced by a N9–H···O(IDA-like or sulfate) intra-molecular interligand interaction. [Copyright &y& Elsevier]

Abstract: A new two-dimensional metal organic framework is synthesized and characterized. The encapsulated chloride anions organize a collection of building units into a novel mixed-ligand metal organic supramolecular assembly, indicating specific host–guest recognition. By contrast, the addition of F−, Br−, I−, anions only give out the coordination complexes with single ligand. Reactions of the Zn2+ ion with 1,2,4-benzenetricarboxylic acid and pyridine-2,5-dicarboxylic acid have been investigated with emphasis on the factors that govern reaction results. And the sample is characterized by the elemental analysis, TGA, XPRD, IR, and luminescent data. [Copyright &y& Elsevier]

Abstract: The synthesis, X-ray structure, electronic structure, bonding, photoluminescence, spectroscopic property and characterization of an indium(III) complex, [In(Hbsac)3(phen)] (1) (H2bsac=5-bromo-salicylic acid, and phen=1,10-phenanthroline) are presented. Complex 1 is octacoordinate and carboxylate chelating, being novel and rarely reported for main group complexes. The electronic structure, bonding and the charge transfer properties of light excitation and light emission are discussed in detail using first-principles theory, including partial density of states (PDOSs), crystal orbital overlap population (COOP), the density functional theory (DFT/TDDFT) analysis schemes. The charge transfer is mainly π→π∗ intraligand charge transfer transition (ILCT) for excitation, and π→π∗ ligand-to-ligand charge transfer transition (LL′CT) for emission in nature. [Copyright &y& Elsevier]