Coordination Mode Of Ligand Research Articles

Magnetic properties and crystal structures of two copper coordination compounds with pentafluorobenzoate ligand

Two copper coordination compounds, [Cu2(OOCC6F5)6](Et3NH)2 (1) and {(Et3NH)[Cu2(OOCC6F5)5]}n (2, [Cu2(OOCC6F5)4] as paddle-wheel secondary building unit, OOCC6F5 = pentafluorobenzoate ligand), have been obtained and characterized. The coordination modes of axial ligands were different in compound 1 and 2, resulting to different crystal structures and magnetic properties. The zero-dimensional molecule compound 1 indicated two magnetic orderings. At low temperature (T < 70 K), a weak ferromagnetic ordering was observed, and an antiferromagnetic behavior took place beyond this temperature (T > 70 K). However, one-dimensional chained compound 2 exhibited intramolecular antiferromagnetic exchange coupling in the range 2–300 K. Moreover, the correlation of magnetism and structure was discussed.

Investigation of the effect of sodium azide on the coordination mode of flexible ONO-donor hydrazone ligand in preparing manganese coordination compounds

Mononuclear Mn(II) coordination compound, [Mn(H2L)Cl2] (1), was synthesized by the reaction of H2L and MnCl2·4H2O in methanol where H2L is tridentate ONO-donor hydrazone ligand [H2L = (E)-N'-(2-hydroxy-5-iodobenzylidene)isonicotinohydrazide]. The reaction of H2L with MnCl2·4H2O in the presence of excess amount of NaN3 in methanol gave an azido bridged dinuclear Mn(III) coordination compound, [Mn2(L)(μ-N3)2(CH3OH)2] (2), whereas in the presence of low amount of NaN3, a phenolate bridged dinuclear Mn(II) coordination compound, [Mn2(HL)2(CH3OH)2Cl2]·CH3OH (3), was obtained. These compounds were characterized by elemental analysis, spectroscopic methods, single crystal X-ray analysis and magnetic measurements. The structural studies indicated that the ligand is coordinated as ONO-donor ligand in 1–3 and behave as a neutral, dianionic and monoanionic ligand in compounds 1, 2 and 3, respectively. There is a good agreement between spectroscopic properties and structures of the compounds. Several synthetic attempts indicated that the azide anion has considerable effect on the formation of phenolate bridged dinuclear Mn(II) coordination compound which attributed to its general basic properties. Magnetic measurements indicate the formation of dinuclear molecules with ferromagnetic intramolecular couplings in the case of 2 and 3 as well as with much weaker and distributed antiferromagnetic interactions among the dinuclear units of these compounds.

Role of Metals and Thiolate Ligands in the Structures and Electronic Properties of Group 5 Bimetallic-Thiolate Complexes.

Syntheses, structures, and electronic properties of group 5 metal-thiolate complexes that exhibit unusual coordination modes of thiolate ligands have been established. Room-temperature reaction of [Cp*VCl2]3 (Cp* = η5-C5Me5) with Na5[B(SCH2S)4] led to the formation of [Cp*VO{(SCH2)2S}] (1). The solid-state X-ray structure of 1 shows the formation of six-membered l,3,5-trithia-2-vanadacyclohexane that adopted a chair conformation. In a similar fashion, reactions of heavier group 5 precursors [Cp*MCl4] (M = Nb or Ta) with Na5[B(SCH2S)4] yielded bimetallic thiolate complexes [(Cp*M)2(μ-S){μ-C(H)S3-κ2S:κ2S',S″}{μ-SC(H)S-κ2C:κ2S‴,S''''}] (3a: M = Nb and 3b: M = Ta). One of the key features of molecules 3a and 3b is the presence of square-pyramidal carbon, which is quite unusual. The reactions also yielded bimetallic methanedithiolate complexes [(Cp*Nb)2(μ-S)(μ-SCH2S-κ2S,S')(μ,η2:η2-BH3S)] (2) and [(Cp*Ta)2(μ-O)(μ-SCH2S-κ2S,S')(μ-H){μ-S2C(H)SCH2S-κ2S″:κ2S‴,S''''}] (4). Complex 2 contains a methanedithiolate ligand that stabilizes the unsaturated niobaborane species. On the other hand, one ((mercaptomethyl)thio)methanedithiolate ligand {C2H4S3} is present in 4, which is coordinated to metal centers and exhibits the {μ-κ2S″:κ2S‴,S''''} bonding mode. Along with the formation of 3b and 4, the reaction of [Cp*TaCl4] with Na5[B(SCH2S)4] yielded [(Cp*Ta)2(μ-S){μ-(SBS)S(CH2S)2(BH2S)-κ2B:κ2S:κ4S',S″,S‴,S''''}] (5) containing a trithiaborate unit (BS3). Complex 5 consists of pentacoordinate boron that resides in a square-pyramidal environment. All the complexes have been characterized by multinuclear NMR, UV-vis spectroscopy, mass spectrometry, and single-crystal X-ray diffraction studies.

Template-directed hierarchical copper(II)-organophosphonate compounds: Syntheses, crystal structures, magnetic and luminescence properties

Three new copper organodiphosphonate compounds, [C4N2H14][Cu(hedph2)2], I, [C4N2H12][Cu3(hedp)2(H2O)4], II and [C6N2H18][Cu3(hedp)2].4H2O, III have been synthesized hydrothermally in the presence of copper nitrate, 1-hydroxyethane-1,1-diphosphonic acid (hedpH4) and various organic aliphatic amines. Molecular structure of compound I is formed in presence of templated 1,4-diaminobutane (DAB). One-dimensional ladder structure of compound II and two-dimensional layer structure of III are observed in the presence of templated piperazine (PIP) and 1,6-diaminohexane (DAH), respectively. The coordination behaviour of the diphosphonate ligand and the organic amines play the crucial role for isolating the different dimensionality amongst the hybrid structures. Although, the compounds II and III display eight-membered rings assembled through vertex-sharing Cu-polyhedra and CPO3 tetrahedra, but the higher coordination mode of diphosphonate ligand can make the 2D layer structure of II instead of 1D ladder of I. The dc-magnetic measurements and theoretical fitting of interacting Cu•••Cu exchange interactions exhibit the antiferromagnetic ordering with weak ferromagnetic coupling in higher-dimensional structures. All the compounds are well characterized by powder XRD, IR, elemental and thermal analysis. The magnetic and luminescence properties of compounds I‒III have also been studied.

Ligand-regulated assemblies of three 1D to 3D Cu(II) coordination polymers: Structural diversities and magnetic properties

Three structurally diverse Cu(II) coordination polymers (CPs) from one-dimension (1D) to three-dimension (3D) upon nicotinate N-oxide (NNO) and isonicotinate N-oxide (INO) ligands have been synthesized solvothermally. CP 1 [Cu3(NNO)4(OH)2(H2O)2]n based on NNO ligand displays a 1D wavy double-chain. CP 2 [Cu(INO)(OH)]n based on INO ligand possesses a 2D wavy double-sheet. CP 3 [Cu(INO)(CH3O)]n based on INO ligand exhibits a 3D framework with 1D wavy channels. Structural comparisons indicate that the position of functional group of ligand, the coordination modes of ligand, the solvent system determine these diversified CPs. And Moreover, the structural diversity of CPs 1–3 further result in their different magnetic behaviors.

Impacts of coordination modes (chelate versus bridge) of PNP-diphosphine ligands on the redox and electrocatalytic properties of diiron oxadithiolate complexes for proton reduction

As diiron subsite models of [FeFe]-hydrogenases with odt bridge, two new series of PNP-chelate or -bridge diiron oxadithiolate complexes Fe2(μ-odt)(CO)4{(Ph2P)2NR} (1–3 and 4–6) were prepared by selective substitutions of diiron hexacarbonyl complex Fe2(μ-odt)(CO)6 (A, odt = SCH2OCH2S) with different PNP ligands (PNP = (Ph2P)2NR, R = (CH2)3Me, (CH2)3NMe2 and (CH2)3Si(OEt)3). All the new model complexes have been fully characterized by elemental analysis, various spectroscopies, and particularly for 1 and 4–6 by X-ray crystallography. In order to investigate the influence of coordination modes (chelate vs. bridge) of PNP ligands on redox and electrocatalytic properties of diiron model complexes for proton reduction, the protonation and electrochemistry of 1 and 4 as a pair of representative counterparts are well studied and compared in the absence and presence of strong acid (CF3CO2H) and weak acid (CH3CO2H) as different proton sources by using in situ IR and NMR spectroscopies as well as cyclic voltammetry (CV). For example, the protonation studies have shown that i) with excess CF3CO2H, protonations of both 1 and 4 are able to form the respective hydride species 1(μH)+ and 4(μH)+, but in which the former is completely protonated whereas the latter is less reactive; and ii) with excess CH3CO2H, complex 1 is unactive yet counterpart 4 is partially protonated to afford species 4(μH)+. The electrochemical investigations have displayed that i) with CF3CO2H as a proton source, complex 1 has a very simliar turnover frequency (TOF) and a much lower overpotential for cataytic proton reduction to H2 in comparison to 4; and ii) with CH3CO2H as a proton source, complex 1 shows a much greater TOF value and a closer overpotential for H2 evolution in contrast to 4.

Solid-state phase transformations toward a metal-organic framework of 7-connected Zn4O secondary building units

In the development of metal-organic frameworks (MOFs), secondary building units (SBUs) have been utilized as molecular modules for the construction of nanoporous materials with robust structures. Under solvothermal synthetic conditions, dynamic changes in the metal coordination environments and ligand coordination modes of SBUs determine the resultant product structures. Alternatively, MOF phases with new topologies can also be achieved by post-synthetic treatment of as-synthesized MOFs via the introduction of acidic or basic moieties that cause the simultaneous cleavage/reformation of coordination bonds in the solid state. In this sense, we studied the solid-state transformation of two ndc-based Zn-MOFs (ndc = 1,4-naphthalene dicarboxylate) with different SBUs but the same pcu topology to another MOF with sev topology. One of the chosen MOFs with pcu nets is [Zn2(ndc)2(bpy)]n (bpy = 4,4′-bipyridine), (6Cbpy-MOF) consisting of a 6-connected pillared-paddlewheel SBU, and the other is IRMOF-7 composed of 6-connected Zn4O(COO)6 SBUs and ndc. Upon post-structural modification, these pcu MOFs were converted into the same MOF with sev topology constructed from the uncommon 7-connected Zn4O(COO)7 SBU (7C-MOF). The appropriate post-synthetic conditions for the transformation of each SBUs were systematically examined. In addition, the effect of the pillar molecules in the pillared-paddlewheel MOFs on the topology conversion was studied in terms of the linker basicity, which determines the inertness during the solid-state phase transformation. This post-synthetic modification approach is expected to expand the available methods for designing and synthesizing MOFs with controlled topologies.

Palladium complexes of chalcogenoethanamine (S/Se) bidentate ligands: Applications in catalytic arylation of C[sbnd]H and O[sbnd]H bonds

This report describes the syntheses of N,E (E = S, Se) coordinated bidentate palladium complexes, by the reaction of N-(2-bromobenzyl)-2-(phenylthio/selanyl)ethanamine (3, 4) with [PdCl2(CH3CN)2]. The new ligands and palladium complexes were characterized by techniques like 1H, 13C{1H} NMR, IR, and elemental analysis. The coordination modes of ligand with palladium precursor in complexes 5 and 6 were authenticated by single crystal X-ray diffraction. The complexes possess distorted square planar geometry around palladium center. Thermally robust and air stable complexes 5 and 6 were used as catalyst for regioselective arylation of imidazole and O-arylation of phenol. In case of regioselective arylation of imidazole, the reaction proceeds smoothly under mild reaction conditions, only 2.0 mol% of catalyst loading is required to achieve high yield (76–92%). This protocol is applicable to a broad substrate scope showing excellent tolerance towards different functional groups. Whereas for O-arylation of phenol also only 2.0 mol% catalyst loading is sufficient to give good yield (71–92%) with excellent tolerance towards a broad range of functional groups. Among sulfur and selenium coordinated ligands, selenium ligand coordinated complex, was found to outperform the catalytic reactions in both cases as compare to sulfur ligand. The mercury and triphenylphosphine poisoning tests suggest homogeneous nature of catalysis.

Antitumor activity of Pd(II) complexes with N,S or O,S coordination modes of acylthiourea ligands

Seven new complexes (1–7) of Pd(II) with N-alkyl- and N,N-dialkyl-N′-acylthioureas were prepared and characterized by elemental analysis and spectroscopic techniques. The crystal structures of the coordination compounds [PdCl(PPh3)(5-cloropiridyl-N′-benzoylthioureato-k2N,S)] (2), cis-[Pd(PPh3)2(N-morpholyn-N′-benzoylthioureato-k2O,S)]PF6 (4) and cis-[Pd(PPh3)2(N,N-diphenyl-N′-thiophenylthioureato-k2O,S)]PF6 (7) were determined by X-ray crystallography. The present study reports on an interesting contribution on the chemistry of Pd(II)/acylthiourea complexes, where the use of monosubstituted acylthiourea conducts to formation of neutral complexes with general formula [Pd(Cl)(PPh3)(acylthiourea)], with a N,S-coordination mode. On the other hand, cationic complexes with formula [Pd(PPh3)2(acylthiourea)]+, with O,S bidentately coordinated to the metal, are obtained by using a disubstituted acylthiourea derivative. The antitumor activity of the N-alkyl- and N,N-dialkyl-N′-acylthiourea ligands and their palladium (II) complexes with synthesized triphenylphosphine were evaluated against the growth of the DU-145 tumor cells (prostate cancer cells), (MDA-MB-231 (breast cancer cells), L929 (healthy mouse cells). The ligands are not cytotoxic, but the complexes showed good cytotoxicity against the tumor cells tested in this work, and were even better, when compared to the IC50 reported for the cisplatin. The complexes showed better activity results in MDA-MB-231 tumor cells, than for the DU-145 tumor cells. Complexes 1 and 6 showed high cytotoxic activity at low micromolar concentrations (IC50 = 1.93 ± 0.45, 0.62 ± 0.08 μM) against MDA-MB-231 (human breast cancer cells). This result indicated that the binding of the ligands to the metal center increases their antitumor activity.

Imidazole Multi-Carboxylate-Based 2D Cd(II) MOF: Preparation, Crystal Structure, and Properties

By adopting one imidazole multi-carboxylate ligand, 2-(3-carboxylphenyl)-1H-imidazole-4,5-dicarboxylic acid (m-CPhH4IDC) and one N-containg ligand, 2,2′-bipyridine (2,2′-Bipy) to react with Cd(NO3)2, under solvothermal condition, a two-dimensional metal-organic framework, {[Cd6(m-CPhHIDC)4(2,2′-Bipy)6] · 4H2O}n (I) has been sucessfully constructed. The structure has been determined by single-crystal X-ray diffraction analysis (CIF files CCDC no. 1480230) and further characterized by elemental analyses, IR spectra, and thermogravimetric analysis. MOF I exhibits a rare (3,4)-connected 2D structure bearing two kinds of organic ligands. According to the crystal data, the coordination ability and mode of the imidazole multi-carboxylate ligand are discussed. Furthermore, the thermal stability and solid-state photoluminescent properties of MOF I have been investigated.

Selective Coordination Mode of Acylthiourea Ligands in Half-Sandwich Ru(II) Complexes and Their Cytotoxic Evaluation.

In this study, half-sandwich Ru(II) complexes containing acylthiourea ligands of the general type [Ru(η6-p-cymene)(PPh3)(S)Cl]PF6 (1m-6m) and [Ru(η6-p-cymene)(PPh3)(S-O)]PF6 (1b-6b) where S/S-O = N',N'-disubstituted acylthiourea were synthesized and characterized (via elemental analyses, IR spectroscopy, 1H NMR spectroscopy, 13C{1H} NMR spectroscopy, and X-ray diffractometry), and their cytotoxic activity was evaluated. The different coordination modes of the acylthiourea ligands, monodentately via S (1m-6m) and bidentately via S,O (1b-6b), to ruthenium were modulated from different synthetic routes. The cytotoxicity of the complexes was evaluated in five human cell lines (DU-145, A549, MDA-MB-231, MRC-5, and MCF-10A) by MTT assay. The IC50 values for prostate cancer cells (2.89-7.47 μM) indicated that the complexes inhibited cell growth, but that they were less cytotoxic than cisplatin (2.00 μM). Unlike for breast cancer cells (IC50 = 0.28-0.74 μM) and lung cancer cells (IC50 = 0.51-1.83 μM), the complexes were notably more active than the reference drug, and a remarkable selectivity index (SI 4.66-19.34) was observed for breast cancer cells. Based on both the activity and selectivity, complexes 5b and 6b, as well as their respective analogous complexes in the monodentate coordination 5m and 6m, were chosen for further investigation in the MDA-MB-231 cell line. These complexes not only induced morphology changes but also were able to inhibit colony formation and migration. In addition, the complexes promoted cell cycle arrest at the sub-G1 phase inducing apoptosis. Interaction studies by viscosity measurements, gel electrophoresis, and fluorescence spectroscopy indicated that the complexes interact with the DNA minor groove and exhibit an HSA binding affinity.

Lanthanide complexes based on the linear bifunctional ligand: Synthesis, structure regulation and magnetic properties

Two kinds of lanthanide(Ш) complexes based on 2-(4-(1H-imidazol-1-yl)phenyl)-1H-benzo[d]imidazole-5-carboxylic acid (H2L) ligand, [Ln(HL)2(H2O)4](Cl)4·2H2O (Ln = Ho, 1; Dy, 2), [Ln(HL)2(H2O)4]OH·3H2O (Ln = Sm, 3; Tb, 4), [Pr(HL)2(NO3)(H2O)3]NO3·4H2O (5), {[Gd7(HL)9(μ3-OH)8(H2O)6](Cl)2(OH)2·4.5H2O}n (6) and {[Ln7(HL)9(μ3-OH)8(H2O)6](OH)4·4.5H2O}n (Ln = Ho, 7; Dy, 8; Er, 9) were solvothermally synthesized by stimulating temperature conditions. The single-crystal structure analysis reveal that 1–5 exhibit distinct mononuclear structure, and the structure of 6–9 can be described directly as 2D coordination polymers constructed from heptanuclear nodes, and the 2D heptanulear cluster layer has a thickness of 10.98 Å along b axis, which can be further stacked together by intermolecular O6–H6B∙∙∙N5 hydrogen bonds to obtain a 3D supramolecular structure with a diameter about 15.23 Å along c axis. Obviously, the change of ligand coordination mode through the subtle change of reaction temperature leads to the transformation of the structure of complexes from zero-dimensional mononuclear to two-dimensional heptanuclear. The magnetic properties of complexes (1, 2, 5, 6, 7 and 8) were studied.

Synthesis and crystal structure of a phenolato, chlorido and end-on azido-cobridged tetranuclear copper(II) complex derived from 2-[(2-dimethylaminoethylimino)methyl]-4-methylphenol

A novel phenolato-, chlorido- and end-on azido-cobridged tetranuclear copper(II) complex, [Cu4(daemp)2Cl2(μ-Cl)2(μ1,1-N3)2(MeOH)2] (Hdaemp = 2-[(2-dimethylaminoethylimino)methyl]-4-methylphenol), was prepared and characterized by elemental analyses, IR and UV-Vis spectra, and single crystal X-ray diffraction study. The Schiff base ligands coordinate to the Cu atoms through phenolate O, imino N and amino N atoms. The adjacent Cu···Cu distances are 3.169(2) and 3.063(2) Å. Each Cu atom is in a square pyramidal coordination. The azido ligands link two Cu atoms with end-on bridging mode. There are two coordination modes for the Cl ligands, viz. terminal and bridging. In the crystal structure, the complex molecules are stack along the b axis.

Rational synthesis, structural characterization, theoretical studies, antibacterial activity and selective dye absorption of new silver coordination polymers generated from a flexible bis (imidazole-2-thione) ligand

Herein, a competition between the different anions with different size, shape and coordination ability was used for the synthesis of three silver(I)-coordination polymers (Ag-CPs) was investigated. In this study, three 3D-supra-molecular coordination compounds namely, [Ag2L(NO3)2]n (1), {[Ag2L][PF6]2}n (2) and [AgLBr]n (3) (L = 1,1′-(1,5-pentadienyl)bis-(1,3-dihydro-3-methyl-1H-imidazole-2-thione)) have been synthesized and fully characterized via a single crystal X-ray diffraction, powder X-ray diffraction (PXRD), elemental analysis (CHN), FT-IR spectra and thermo gravimetric analysis (TGA). Structural analysis revealed that the counter ions have a notable impact in directing the conformation and coordination mode of ligand, but they have no effect on the structural dimension of the polymers. Furthermore, by increasing the coordination ability of the anions, the coordination geometry of the AgI centers change, from a distorted linear (for 2) to a distorted square pyramidal coordination geometry (for 1). The chains are further stabilized by the intermolecular CH⋯O and CH⋯N for 1, P–F…HC for 2, CH⋯Br and CH⋯N interactions for 3 to form a 3D non-covalent lattice network structure. In contrast to the 1 and 3, polymer 2 exhibits a large capacity and selectivity to adsorb dye from aqueous solutions. Sorption kinetic was investigated by three kinetic models. The electronic band structure and the projection densities of states (PDOS) of compounds 1 and 3 were investigated by means of DFT-D3. The results demonstrated that both compounds are non-magnetic and show a semiconducting character with a direct band gap of ~3 eV. All of the synthesized compounds, possess antibacterial activity against the selected strain of Gram- negative (Escherichiacoli, Pseudomonas aeruginosa) and Gram- positive (Staphylococcus aureus, Bacillus subtilis) bacteria.

Designing a colorimetric sensor containing nitrogen and oxygen atoms for uranyl ions identification: Chromatic mechanism, binding feature and on-site application

It is still a challenge for scientists to eliminate interference and improve chromatic aberration in designing colorimetric uranyl ions sensors, and it is also not clear how the species of uranium and sensor synergistically affect the coloration mechanism and coordination mode of ligands containing nitrogen or oxygen atoms at different pH. Herein, we design and synthesize 2-(5′-(p-(diphenylamino)phenyl)-2′-pyridylazo)-5-(diethylamino)phenol (abbr. S-LH) for the colorimetric detection of uranyl ions in mixed solvents. The rational introduced triphenylamine group by density functional theory (DFT) calculation enhances the chromaticity difference of the S-LH toward uranyl ions, making the detection limits of the uranyl ions approximately one order of magnitude lower than that of the present UV–vis and visual method. The species of S-LH and uranium at different pH are clarified and it well explains the reason of different color changes after adding uranyl ions. Stability constant experiments show that S-LH has excellent anti-interference to other metal ions during detecting uranium. The coordination structure of S-LH towards UO22+ is further confirmed by HRMS, 1H NMR titration, and DFT calculation. Finally, colorimetric test strips with S-LH are prepared to detect uranium in Xiang River, providing an on-site and real-time method to detect uranyl ions in the environment.

Tetrazole-based porous metal-organic frameworks for selective CO2 adsorption and isomerization studies.

Tetrazole-based molecules have numerous bridging coordination modes which afford great synthetic possibilities for the preparation of porous metal-tetrazolate architectures for many applications, such as carbon capture. We reported here three tetrazole-based MOFs: 1, {[Cu12(ttz)8/3Cl5(H2O)16]11+·11Cl-}n (H3ttz = N2,N4,N6-tris(4-(1H-tetrazol-5-yl)phenyl)-1,3,5-triazine-2,4,6-triamine), contains highly positively charged Cu12 clusters and the largest mesopores (32 Å) among the reported MOFs based on a tri-topic tetrazole ligand. 2 and 3 are two MOF isomers built by using CuII and 2-(1H-tetrazol-5-yl)pyrimidine. 3 contains nonporous layers, while 2 contains 1D channels and showed high selectivity for adsorbing CO2, which should be attributed to the high density of free nucleophilic tetrazole N atoms on the pore surfaces. We found that the isomerization between 2 and 3 was caused by the diverse coordination modes of tetrazole-based ligands and can be controlled in synthesis processes.

Synthesis and characterization of copper (II) octaazamacrocyclic complexes with glycine derivatives. In vitro antiproliferative and antimicrobial evaluation of Cu(II) and Co(II) analogous

Two new complexes with the general formula [Cu2(L)tpmc] (ClO4)3?nH2O (tpmc = N,N?,N??,N???-tetrakis(2-pyridylmethyl)- -1,4,8,11-tetraazacyclotetradecane, L = N-methylglycine, n = 3; L = N,N- -dimethylglycine, n = 2) were isolated and their composition, some physical and chemical properties and geometries were proposed based on elemental analysis (C, H, N), conductometric and magnetic measurements and spectroscopic data (UV?Vis, FTIR). It is evident that the complexes are binuclear and an exo coordination mode of the macrocyclic ligand in the boat conformation was proposed. The co-ligands are coordinated as a bridge using both oxygen atoms of the OCO- group. The cytotoxic activity of Cu(II) complexes as well as their Co(II) analogs, the starting ligands and the free salts were tested against human cervix adenocarcinoma cell line (HeLa), human chronic myelogenous leukemia cells (K562), human breast cancer cell line (MDA-MB-453), and a non-cancerous cell line, human embryonic lung fibroblast (MRC-5). The IC50 values for the Cu(II) complexes were from 21.6?0.04 to 66.1?0.8, and for the Co(II) analogs were within the range from 8.8?0.74 to 15.40?1.52. All four complexes were tested for their antimicrobial activity against Staphylococcus aureus, Bacillus subtilis, Escherichia coli and the yeast Candida albicans.

Temperature-induced structural transformations accompanied by changes in magnetic properties of two copper coordination polymers

Two ferromagnetic copper compounds have been synthesized under different temperature, which represented the rare example of structural transformations resulting from the coordination modes of organic ligands supported by magnetic results.

Syntheses, structures and magnetism of two Cu(II) coordination polymers of d-camphorate controlled by metal-ligand ratio

By controlling the metal-ligand ratios, two new Cu(II) coordination polymers based on d-camphoric acid (H2DCA) and 1,4-bis(imidazol-1-yl)-butane (bimb), {[Cu2(DCA)2(bimb)2(H2O)]2·7H2O}n (1), and {[Cu2(DCA)2(bimb)]}n (2), have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction, IR and UV–Vis spectra, powder X-ray diffraction. Comparative investigation showed that the different metal-ligand ratios affected the coordination modes of ligand and thus resulted in two distinct structures from 1D chain to 3D network. In 1, the Cu(II) centers are connected by DCA2− and bimb into 1D chains, and (H2O)4 water clusters connect the 1D chains into a 3D supramolecular structure via OH⋯O hydrogen bonds. Differently, the Cu(II) centers in 2 are bridged by four carboxyl of DCA2− to form the binuclear paddle-wheel [Cu2(O2CR)4] units, which are pillared by bimb ligands into a 3D framework showing 6-connected pcu topology. Moreover, thermogravimetric and magnetic properties of the two CPs have also been investigated.

Lanthanide-Based Metal-Organic Frameworks Containing "V-Shaped" Tetracarboxylate Ligands: Synthesis, Crystal Structures, "Naked-Eye" Luminescent Detection, and Catalytic Properties.

Three lanthanide-based metal-organic frameworks, [Tb(HMDIA)(H2O)3]·H2O (Tb-MDIA), [Ho(HMDIA)(H2O)3]·(H2O)2 (Ho-MDIA), and [Nd(HMDIA)(H2O)3]·(H2O)2 (Nd-MDIA) from the same V-shaped ligand 5,5'-methylenediisophthalic acid (H4MDIA), were prepared by mixing Ln3+ and H4MDIA under solvothermal conditions. The crystal structures of the three complexes were determined by single-crystal X-ray diffraction. The different coordination modes of the organic ligands resulted in different framework structures among the three complexes. The luminescent properties of Ln-MDIA in the ultraviolet-visible region were also studied. Interestingly, the bright-green emitter Tb-MDIA showed high selectivity and sensitivity to allow the naked-eye visualization of Fe3+ ions and picric acid (PA) explosive, and both sensing mechanisms were revealed. Finally, Ho-MDIA and Nd-MDIA were shown to work as heterogeneous catalysts for the cyanosilylation reaction of aromatic aldehydes, and the catalysts could be recycled at least three times without any decrease in activity.