Structure and luminescent property of one three-dimensional cadmium(II) polymer derived from mixed flexible and rigid ligands

One new three-dimensional Cd(II) polymer [Cd₃(MMA)₂(INA)₂]_n (1) was synthesized hydrothermally based on mixed flexible methylmalonic acid (H₂MMA) and rigid isonicotinic acid (HINA) ligands. Single-crystal X-ray diffraction analysis reveals that compound 1 has a 3D framework structure consisting of 2D {Cd₃} layer unit and INA⁻ connector, which bears a (3,8)-connected tfz-d topology with Schläfli symbol of {4³}₂{4⁶.6¹⁸.8⁴}. The solid-state luminescent property was studied and 1 exhibits strong emission centered at 429 nm.     

Two novel d frameworks based on a new V-shaped ligand 2,4′-dipyridylamine and a flexible dicarboxylate ligand

Via hydrothermal synthesis, the self-assembly of d¹⁰ metal, 2,4′-dipyridylamine (L) and 1,3-adamantanediacetic acid (H₂ADA) generated two unprecedented coordination polymers [Zn(ADA)(L)]_n (1) and [Cd(ADA)(L)₂]_n (2). Complex 1 possesses a novel 1D looped-chain topology structure decorated with arms. Complex 2 shows an extended threaded framework involving 2D coordination layers of square (4⁴) topology with dangling ligands, which gives the novel (2D → 3D) polythreaded array. To the best of our knowledge, complex 2 is the first example with four dangling arms coordinated in the axial sites of dinuclear nodes. In addition, both of the complexes show strong photoluminescence at room temperature, and may be good candidates for potential luminescence materials.     

Two self-interpenetrating magnetic Mn(II) metal-organic frameworks assembled from rigid or flexible tripodal multicarboxylate ligands

Assembly of two tripodal multicarboxylic ligands, namely rigid 3,4-bis(4-carboxyphenyl)-benzoic acid (H₃L¹) and flexible 3,5-bis(4-carboxyphenoxy)-benzoic acid (H₃L²) with MnCl₂ under hydrothermal conditions afforded two distinct metal-organic frameworks (MOFs), {[Mn₃(L¹)₂(H₂O)₄](H₂O)₂}_n (1) and {[Mn₃(L²)₂(H₂O)₄](H₂O)₄}_n (2), respectively. Interestingly, both complexes possess different 3D networks of novel self-interpenetrating prototype, constructing from different 2D [Mn(COO)₂]_n polymeric motifs. Furthermore, the thermal and magnetic properties of 1 and 2 are studied.     

Graft‐interpenetrating polymer networks of epoxy with polyurethanes derived from poly(ethyleneterephthalate) waste

Polyester polyurethanes derived from poly(ethyleneterephthalate) (PET) glycolysates were blended with epoxy to form graft‐interpenetrating networks (IPNs) with improved mechanical properties. Microwave‐assisted glycolytic depolymerization of PET was performed in the presence of polyethylene glycols of different molecular weights (600–1500). The resultant hydroxyl terminated polyester was used for synthesis of polyurethane prepolymer which was subsequently reacted with epoxy resin to generate grafted structures. The epoxy‐polyurethane blend was cured with triethylene tetramine under ambient conditions to result in graft IPNs. Blending resulted in an improvement in the mechanical properties, the extent of which was found to be dependant both on the amount as well as molecular weight of PET‐based polyurethane employed. Maximum improvement was observed in epoxy blends prepared with polyurethane (PU1000) at a loading of 10% w/w which resulted in 61% increase in tensile strength and 212% increase in impact strength. The extent of toughening was quantified by flexural studies under single edge notch bending (SENB) mode. In comparison to the unmodified epoxy, the Mode I fracture toughness (K_IC) and fracture energy (G_IC) increased by ～45% and ～184%, respectively. The underlying toughening mechanisms were identified by fractographic analysis, which generated evidence of rubber cavitation, microcracking, and crack path deflection. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40490.     

Ru(II) and Zn(II) complexes of multicomponent ligands incorporating triazine-based tridentate ligands

Ru(II) and Zn(II) complexes of multicomponent ligands have been synthesised and characterised incorporating triazine-based coordinating motifs with pendant phenanthryl and phenyl–phenanthryl groups. At room temperature the ligands emit from intra-ligand charge-transfer (ILCT) states, the energy of which may be lowered significantly by metal–ion coordination (e.g. Zn(II)). The ILCT state is efficiently quenched in the Ru(II) complexes by energy transfer to a low-lying metal–ligand charge-transfer ³MLCT state.     

A tubular luminescent Zn(II) coordination polymer with unsymmetrical bridge ligand

A novel 1D tubular coordination polymer [ZnL(dca)₂]_n (dca = dicyanamide, L = 2-(3-pyridylmethylthio)-5-(4-pyridyl)-1,3,4-oxadiazole) constructed by the unsymmetrical bridge ligands L spirally winding around two double-chain pillars Zn(dca)₂ was synthesized and characterized.     

水杨醛缩邻甲苯胺Schiff碱及其Zn(Ⅱ)配合物的合成与表征

由水杨醛和邻甲苯胺缩合形成的不对称Sch iff碱与Zn(Ⅱ)盐反应得到了金属配合物。通过元素分析、红外光谱、紫外-可见光谱、核磁共振氢谱(1H NMR)及13C谱(13C NMR)等分析测试手段对配体及其配合物进行了结构表征,确定了配合物的可能结构,结果表明,配体通过N,O原子与金属离子配位。     

Cadmium(II) chloride complexes of imidazole-based ligands: Solvothermal syntheses,crystal structures and luminescent properties

Presented are the solvothermal syntheses, structures, characterizations, and luminescent properties of four novel organic-modified cadmium chloride complexes constructed from CdCl₂ and imidazole (or its derivatives), namely [CdCl₂(Im)₄] (1, Im = imidazole), [CdCl₄(HAPI)₂] (2, API = N-(3-Aminopropyl)-imidazole), [Cd(μ-Cl)₂(1-Mim)₂]_∞ (3, 1-Mim = 1-methyl imidazole) and [CdCl₃(HAPI)]_∞ (4). 1 and 2 feature a zero dimensional (0D) mononuclear structure with different mole ratios of Cd: Cl: ligand, while compound 3 and 4 bear infinite chains constructed from different subunits and connection modes. Worthy of note is that 4 represents a new structural type in the family of organic modified cadmium halides. The fluorescence spectra showed that compounds 1–4 exhibited emission peaks around 450 nm with the quantum yields of 23.01%, 5.84%, 27.31%, 5.71%, respectively.     

Zn(II) ions removal from aqueous solution by Karachi beach sand, a mixed crystal systems

The aim of this research work is to investigate sorption characteristic of beach sand for the removal of Zn(II) ions from aqueous solutions. The sorption of Zn(II) ions by batch dynamic method is carried out using dilute solutions (10⁻⁴ M) of nitric, hydrochloric and perchloric acids along with deionized water and from buffers of pH 2–10. Maximum sorption is noticed from deionized water (88.3%) using 30 min shaking time. Two equations, i.e. Morris–Weber and Lagergren have been tested to track the kinetics of removal process. The Langmuir, Freundlich and Dubinin–Radushkevich (D–R) model are subjected to sorption data to estimate sorption capacity, intensity and energy. The thermodynamic parameters ΔH, ΔS and ΔG are evaluated. The influence of common ions on the sorption of Zn(II) ions is also examined. Some ions reduce the sorption while most of the ions tested have very little effect. It can be concluded that beach sand has potential to remove Zn(II) ions from aqueous solutions at very low concentrations and for the treatment of industrial effluent carrying Zn(II) ions.     

Synthesis,crystal structures and cytotoxic activity of mononuclear nickel(II) and dinuclear zinc(II) complexes with ligand derived from S-benzyldithiocarbazate

Ni(L)₂ (1) and Zn₂(μ-OL)₂(L)₂ (2), (HL = S-benzyl-β-N-(2-bromobenzylidene) dithiocarbazate), were synthesized and characterized by elemental analysis and X-ray single-crystal diffraction analysis. 1 is a mononuclear neutral nickel(II) complex and the center nickel atom is chelated by donors of N₂S₂ possessing a distorted tetrahedral configuration, while in 2, the adjacent two complex molecules are linked through two O atoms to form a dimer and the center zinc atom is five-coordinate in a distorted trigonal–bipyramidal geometry. The cytotoxic activity study indicated that 2 showed potent cytotoxic activity against the human liver hepatocellular carcinoma (HepG2) cancer cell lines, with IC₅₀ 2.4 ± 0.2 μg·mL^− 1, which is slightly weaker than 5-fluoroacil (5-FU) (0.89 ± 0.21 μg·mL^− 1) as reference. A gel electrophoresis assay demonstrated the ability of the complex to cleave the pBR322 plasmid DNA.     

Bio active mixed ligand complexes of Cu(II), Ni(II) and Zn(II): Synthesis,spectral, XRD,DNA binding and cleavage properties

The paper presents the synthesis of complex combinations of Cu(II), Zn(II) and Ni(II) with Schiff bases obtained by the condensation reaction of diphenylglyoxal with 1-amino-4-nitrobenzene (L¹)/1-amino-4-chlorobenzene (L²)/p-anisidine (L³) as the main ligand and 1,10-phenanthroline as the co-ligand respectively. The characterization of newly formed complexes has been done by spectral and molar conductivity studies. The bioefficacy of the ligands and their complexes have been examined against the growth of bacteria and fungi in vitro to evaluate their antimicrobial potential. The in vitro antibacterial and antifungal assay indicates that these complexes are good antimicrobial agents against various pathogens. X-ray powder diffraction illustrates that the complexes have crystalline nature. The effect of the metal complexes on DNA is carried out by pUC19 DNA agarose gel electrophoresis at 50 V for 2 h. The results indicate that the complexes bind to DNA through intercalation and act as efficient cleaving agents.     

Two birds with one stone: Self-assembly of metal–organic coordination complexes with discrete metallamacrocycle and 1D zigzag chain based on a flexible dicarboxylate ligand

To assemble metal–organic coordination complexes, a flexible dicarboxylate ligand, 2,2′-(4,6-dimethyl-5-nitro-1,3-phenylene)bis(methylene)-bis-(sulfanediyl)dibenzoic acid (H₂L), has been designed and synthesized. Using the flexible ligand to assemble with copper ions, a mixture of two metal–organic complexes, Cu₂(L)₂(py)₄·4dmso (1) and Cu₂(L)₂(py)₆·3dmso·py (2), has been generated by solvothermal technology in one glass tube. Through increasing the mole fraction of pyridine, the pure phase of complex 2 was obtained. Both complexes have been characterized by single-crystal X-ray diffraction, elemental analysis, and thermogravimetric analysis. Complex 1 is a discrete rectangular macrocycle. The guest solvents of dimethyl sulfoxide molecules were trapped in the cavity of rectangular metallmacrocycle, resulting in the formation of an infinite supramolecular metal–organic nanotube through van der Waals interactions between the guests and the host molecules. In complex 2, the flexible ligand adopts a syn conformation to assemble with copper ions to form an infinite one-dimensional zigzag chain.     

Helical metallomacrocyclic nickel(II) complexes of a tetradentate N2S2 ligand derived from N-methyldithiocarbazic acid

The structure of the tetradentate sulphur–nitrogen chelating agent, 1,2-phenylenebis(methylene) bis(1-methylhydrazinecarbodithioate) (NSSN) has been determined by X-ray diffraction. In the solid state, the two arms of the ligand remain in E configurations about the hydrazinic C–N bonds. The ligand reacts with hydrated nickel(II) salts in a 3:2 ligand-to-metal ratio yielding dimeric triple helical complexes of general formula, [Ni₂(NSSN)₃]X₄·nH₂O (X = Cl, Br, I, NCS; n = 5, 6, 9) which contain two nickel(II) ions in distorted octahedral environments. An X-ray crystallographic structure determination of the [Ni₂(NSSN)₃]Cl₄·9H₂O complex shows that it is a metallomacrocycle in which each ligand acts as a bis-bidentate chelating agent providing NS donors of one arm to one nickel(II) ion and NS donors of the second arm to a second nickel(II) ion. Each nickel(II) ion adopts a distorted octahedral geometry with a NiN₃S₃ coordination core as shown by their common electronic spectra.     

Construction of Zn(II)/Cd(II) coordination polymers derived from a tetrazole derivative: Syntheses,structures and luminescent properties

Three new coordination polymers [Zn(Htip)Cl(H₂O)]_n (1), [Zn(Htip)₂]_n (2) and [Cd(Htip)₂]_n·2nH₂O (3) were synthesized by reactions of Zn(II)/Cd(II) salts with a multidentate tetrazole-based ligand 2-(4-(tetrazol-5-yl)phenyl)imidazo(4,5-f)(1,10)phenanthroline (H₂tip). Complex 1 possesses an infinite 1D coordination chain, and further forms the final 3D supramolecule through π⋯π stacking interactions. Complexes 2 and 3 are isomorphous, and both of them feature an 8-fold interpenetrating 4-connected 3D framework with the dia topological net and the Schläfli symbol of {6⁶}. In 1–3, the Htip⁻ ligand links two metal centers through three terminal N-donors. The structural analyses indicate that the anions and solvents can subtly influence the formation of the resulting network. Moreover, the thermal stabilities and photoluminescent properties of 1–3 are investigated in the solid state.     

Two nickel coordination polymers with flexible ligand 1,3,5-tri(1,2,4-triazol-1-ylmethyl)-2,4,6-trimethylbenzene

The reaction of 1,3,5-tri(1,2,4-triazol-1-ylmethyl)-2,4,6-trimethylbenzene (ttmb) with Ni(II) salts yields two coordination polymers [Ni₃(ttmb)₂(H₂O)₆Cl₆](H₂O)₃ (1) and [Ni(ttmb)₂(H₂O)₂](NO₃)₂(H₂O)₄ (2). The flexible ligand ttmb shows the cis,cis,cis-conformation and a tri-monodentate coordination mode in 1. Each ttmb links three Ni(II) atoms to form an undulated (3, 4)-connected two-dimensional network. Each undulated two-dimensional network polycatenates other two identical networks, thus giving a rare (2D → 3D) parallel polycatenation network in 1. The ttmb ligand exhibits the cis,trans,trans-conformation and a two-monodentate coordination mode in 2. Each ttmb connects two Ni(II) atoms to construct a two-dimensional (4, 4) network in 2. The thermal stability of compounds 1 and 2 was studied.     

Synthesis and characterization of Cu(I) and Zn(II) complexes with new sulfur-bearing isoxazole- or pyrazole-based ligands

The synthesis of the new ligands 6-(5-methyl-1,2-oxazol-3-yl)-2,3-dihydro-5H-[1,4] dithiino[2,3-c]pyrrole-5,7(6H)-dione (isox′) and 6-(3-methyl-1H-pyrazol-5-yl)-2,3-dihydro-5H-[1,4]dithiino[2,3-c]pyrrole-5,7(6H)-dione (pyraz′) and their coordination chemistry toward Cu(I) and Zn(II), was studied. The ligands and their complexes were characterized using a combination of either multinuclear NMR (¹H and ¹³C{¹H}), HRMS, FTIR or Uv–Vis spectroscopy. The solid state structures of ligand isox′ and complexes [Cu(pyraz′)₂]OTf and [Zn(OOCCF₃)₂(pyraz′)₂] were determined. Interestingly, isox′ presents a yellow luminescence in its free form. Additionally, the ability of isox′ to coordinate as an N–O bidentate ligand or as an N–S bridge between two copper centers, forming a coordination polymer, is studied. The solid state structure of this Cu(I)-isox′ 1D coordination polymer is also reported.     

Syntheses,characterizations, antitumor activities and cell apoptosis induction of Cu(II), Zn(II) and Cd(II) complexes with hydrazone Schiff base derived from isonicotinohydrazide

Three novel complexes, [Cu₄(L)₄Cl₄]·H₂O (1), Zn(L)₂ (2) and Cd(L)₂ (3), based on HL (where HL = 2-acetylpyridine isonicotinohydrazone) were synthesized and characterized by X-ray diffraction analyses. In the tetranuclear complex 1, each copper(II) ion with a distorted square-planar coordination geometry is five-coordinated by one chloride anion, one ON₂ donor set and one 4-pyridine nitrogen atom from another adjacent actylhydrazone ligand. However, the central ions in complexes 2 and 3 possess distorted octahedral coordination geometry, surrounded by two ON₂ donor sets. In addition, all the complexes have excellent antitumor activity towards human lung cancer (A549) and human gastric cancer (SGC7901 and BGC823) cell lines. Furthermore, cell apoptosis induced by complex 1 was detected through TUNEL and Annexin V/PI staining with flow cytometric analysis and western blotting analysis.