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Abstract Two new complexes, [Zn 2 Cl 4 (Fcdpa) 2 ·CH 2 Cl 2 ] n (1) and [CdI 2 (Fcdpa)] n (2) (Fcdpa = N , N -di(4-pyridyl)animomethylferrocene) have been successfully synthesized. The ligand Fcdpa and their metal complexes are characterized by elemental analysis, IR, 1HNMR, PXRD and electrochemistry. Single crystal X-ray diffraction analysis reveals that the metal ions are bridged by Fcdpa ligands to generate one dimensional chain in both complexes 1 and 2. Electrochemical investigation reveals that the redox peaks of Fcdpa , 1 and 2 are similar. Graphical abstract A new ferrocene-based ligand, and its Zn(II) and Cd(II) complexes were synthesized and characterized. The monosubstituted dipyridine ferrocene derivative is a useful building block for constructing 1D complexes. Their structures and electrochemical properties have been studied in detail. Unlabelled Image Highlights • A new monosubstituted dipyridine ferrocene ligand and its Zn(II) 1 and Cd(II) 2 complexes have been synthesized. • The structure of the ligand and the complexes are determined by X-ray study. • The metal ions in the two complexes are connected by the ligand to generate 1D chain, respectively. • Electrochemical properties of the ligand and the two complexes are investigated. [ABSTRACT FROM AUTHOR]

The isothiocyanato Zn(II) complex (1) and mixed isothiocyanato/thiocyanato Cd(II) complex (2) with the condensation product of 2-acetylpyridine and trimethylammoniumacetohydrazide chloride (Girard’s T reagent) (HLCl) were investigated both experimentally and theoretically. The crystal structures of both complexes showed tridentate N2O coordination of hydrazine ligand. In complex 1 square-pyramidal coordination surrounding of Zn(II) consists of deprotonated hydrazone ligand and two isothiocyanato ligands, while in octahedral Cd(II) complex ligand is coordinated without deprotonation as a positively charged species and coordination geometry is completed with two N-coordinated and one S-coordinated NCS− anions. NMR spectroscopy and molar conductivity results for Cd(II) and Zn(II) complexes indicated their instability in solution. DFT calculations were performed to explain coordination preference and stability of complexes 1 and 2 in solid state and in solution. The obtained Cd(II) complex is the first reported mononuclear pseudohalide/halide Cd(II) complex with quinoline-/pyridine-based hydrazone ligands possessing octahedral geometry in solid state. In this complex, H-bonding has significant impact on coordination number and supramolecular assembly in solid state. [ABSTRACT FROM AUTHOR]

The mixed chloride-azide [Zn L (N 3 ) 1.65 Cl 0.35 ] ( 1 ) and chloride-isocyanate [Cd L (NCO) 1.64 Cl 0.36 ] ( 2 ) complexes with the condensation product of 2-quinolinecarboxaldehyde and trimethylammonium acetohydrazide chloride (Girard's T reagent) ( HL Cl) have been prepared and characterized by X-ray crystallography. In complexes 1 and 2 , Zn1 and Cd1 ions, respectively, are five-coordinated in a distorted square based pyramidal geometry with NNO set of donor atoms of deprotonated hydrazone ligand and two monodentate ligands N 3 − and/or N 3 − and Cl − in the case of 1 and OCN − and/or OCN − and Cl − in the case of 2 . The structural parameters of 1 and 2 have been discussed in relation to those of previously reported M(II) complexes with the same hydrazone ligand. Density functional theory calculations have been employed to study the interaction between the Zn 2+ and Cd 2+ ions and ligands. High affinity of ligands towards the Zn 2+ and Cd 2+ ions are predicted for both complexes. [ABSTRACT FROM AUTHOR]

Complexes ZnLCl ( I) and [CdLCl] ( IV), where L is chiral bis-pyridine containing fragments of natural monoterpenoide (-)-α-pinene are synthesized. Single crystals of [ZnLCl]·CHCl ( II), [ZnLCl]· i-PrOH ( III), and IV compounds are grown. The crystal structures of II and III are composed of mononuclear ZnLCl complex molecules and solvate CHCl and i-PrOH molecules; the coordination polyhedron of the zinc atom ClN is a distorted tetrahedron. According to the single crystal XRD data, complex IV is a 1D coordination polymer; the coordination core CdNCl is a distorted octahedron and Cl atoms are bridging ligands. In the structures of II, III, and IV the L molecule functions as a bidentate chelate ligand. In the solid phase, complexes I and IV exhibit photoluminescence in the visible range (λ 505 nm and 460 nm respectively). The band intensity in the photoluminescence spectra of I and IV complexes considerably exceeds the band intensity in the spectrum of free L. [ABSTRACT FROM AUTHOR]

Isothiocyanate complexes of Zn(II) and Cd(II) with the condensation product of 2,6-diacetylpyridine and trimethylammoniumacetohydrazide (Girard’s T reagent) were synthesized, characterized, and their antimicrobial activities were evaluated. The structures of the complexes were determined by elemental analysis, IR, and NMR spectroscopy. The crystal structure of the Zn(II) complex was also determined. Quantum-chemical calculations of the geometry and total energy of isomers of 2,6-diacetylpyridine-bis(trimethylammoniumacetohydrazone) were performed in vacuum and methanol solution, with the aim to explain conformational behavior andE/Zisomerism of this compound. DFT calculations of the molecular structures and the relative stabilities of linkage isomers of the Cd(II) complex showed that the isomer with N–Cd–N coordination of SCN−is the most stable. Complexes of Zn(II) and Cd(II) exhibited low to moderate activity against the tested microbial strains. [ABSTRACT FROM AUTHOR]

Two new complexes, {[Zn(imb)(SO4)]·H2O}n(1) and {[Cd2(imb)2(SO4)2(H2O)]·CH3OH}n(2) (imb?=?2-(1H-imidazol-1-methyl)-1H-benzimidazole), have been solvothermally synthesized. Single-crystal X-ray diffraction shows that1displays a 2-D (4,4) network, which is further extended to a 3-D supramolecular structure by hydrogen bonding interactions. Complex2exhibits a 3-D framework with (3,5)-connected (42·6)2(42·65·83)2topology. The results indicate that changing metal ions can influence the coordination modes of sulfate, and then affect the structures of the complexes. In addition, IR and UV–vis spectra, powder X-ray diffraction patterns, thermogravimetric analyses, and fluorescent properties of both complexes have been investigated. Two new complexes, {[Zn(imb)(SO4)]·H2O}n(1) and {[Cd2(imb)2(SO4)2(H2O)]·CH3OH}n(2), have been synthesized and characterized by single crystal X-ray diffraction. Additionally, their UV–vis, IR, Thermogravimetric analyses and fluorescent properties are also investigated. [ABSTRACT FROM AUTHOR]

Highlights: [•] Two new Zn (II) and Cd (II) coordination complexes have been synthesized and characterized. [•] Both complexes show interesting 1D linear like coordination polymers. [•] The solid photoluminescence properties for both complexes were also investigated. [•] The fluorescence intensity of Zn derivative was 20 times higher than that of Cd derivative. [ABSTRACT FROM AUTHOR]

Abstract: The new complexes [Co(ecpzdtc)3] (2) [Zn(ecpzdtc)2(py)] (3) and [Cd(ecpzdtc)2(py)]·H2O (4) have been synthesized from sodium 1-ethoxycarbonyl-piperazine-4-carbodithioate [(Na+(ecpzdtc)−]. The ligand and the complexes have been characterized by elemental analyses, IR, magnetic susceptibility and single crystal X-ray data. The [Zn(ecpzdtc)2(py)] and [Cd(ecpzdtc)2(py)]·H2O complexes contain pyridine as the co-ligand. [Co(ecpzdtc)3] (2) crystallizes in the monoclinic system, whereas [Zn(ecpzdtc)2(py)] (3) and [Cd(ecpzdtc)2(py)]·H2O (4) crystallize in the triclinic system. The sulfur donor sites of the bidentate ligand chelate the metal center, forming a four-membered CS2M ring. The cobalt complex has a distorted octahedral geometry, the zinc complex is almost between trigonal bipyramidal and square pyramidal, whereas the cadmium complex is square pyramidal. The crystal structures of all the complexes are stabilized by various types of inter and intramolecular hydrogen bonding. [Copyright &y& Elsevier]

The aqueous reactions of zinc(II) and cadmium(II) nitrate and pyridine-2,6-dicarboxylic acid, (pydcHz), with 9-aminoacridine, (AAcr), resulted in the formation of two new proton transfer compounds, (AAcrH)2[Zn(pydc)2]⋅3H20 (1) and (AAcrH)2[Cd(pydc)2]⋅4H20 (2). The compounds were characterized using IR spectroscopy and single crystal X-ray diffraction. Both compounds crystallized in the triclinic crystal system, space group P1, with two molecules per unit cell. The anions were six-coordinate complexes with distorted octahedral geometries around the Zn(ll) and Cd(II) centers. The dihedral angles indicated that the two (pydc)² ligands were almost perpendicular to each other. The complex anions of [M(pydc)2]² were neutralized wit + (AAcrH) cations. These cations formed extended stacks throughout the structures. The water molecules clustered around cyclic tetramers, bridging the anions and forming a link to the aminoacridiunium stacks. A potentiometric pH titration method was used to investigate the protonation constants of AAcr and pydc, the pydc-AAcr proton transfer equilibrium constants, and the stoichiometries and stabilities of complex formation with Zn2+ and Cd2+ ions in 50% dioxane-50% water. [ABSTRACT FROM AUTHOR]

Abstract: Two new coordination compounds, [Zn2(HL)(L)(H2O)3]n (1), {[Cd3(L)2(H2O)4]∙H2O}n (2) (H3L=2,4,6-tri (3-carboxyphenylthio) -1,3,5-triazine), were synthesized hydrothermally and characterized by single-crystal X-ray diffraction. 1 is a 1D wave-like infinite chain which is further connected by hydrogen-bond and noncovalent S…S interactions to form a 3D supramolecular architecture. 2 features 2D layered structure and further forms a 3D supramolecular network based on hydrogen-bond interactions. In addition, both 1 and 2 show strong blue photoluminescence at room temperature resulting from ILCT. [Copyright &y& Elsevier]

Abstract: Two novel Cd(II) and Zn(II) complexes with the condensation product of 2-formylpyridine and selenosemicarbazide were synthesized. The structure of Cd(II) complex was determined by X-ray crystallography. The ligand is coordinated in a neutral form via pyridine and azomethine nitrogen atoms and the selenium donor. The cadmium ion completes its five-coordination by two chloride ligands, forming a square-pyramidal geometry. The structure of Zn(II) complex was established by analysis of spectroscopic data, which indicated coordination of the ligand as a bidentate via the selenium and the azomethine nitrogen atoms. The cytotoxic activity of the newly synthesized complexes, as well as if five structurally related complexes and the ligand evaluated against eight tumor cell lines. The new Cd(II) complex showed the highest activity similar to cisplatin with IC50 less than 10μM for all cell lines. Cell cycle distribution and apoptosis study showed that Cd(II) complex and cisplatin might have some similarity in anticancer activity, which was not the case for cisplatin and other studied complexes. Effects of the complexes on matrix metalloproteinases (MMPs) MMP-9 and MMP-2 was also studied. Cd(II) and Zn(II) complexes and cisplatin increased MMP-2 activity in supernatants of tested cells, while Ni(II) complex with the same ligand decreased the activity, implying a possible activity in preventing tumor invasion and metastasis processes. [Copyright &y& Elsevier]

New humic acid isolated from forest soil of Yakouren (YHA), Algeria, and purified commercial humic acid (PCHA) were analyzed and characterized. Elemental analyses, electronic microscopy, UV-Vis absorbance E465/E665 ratio and molecular spectroscopy investigation using CP-MAS 13C-NMR of YHA indicated the presence of a high content of aliphatic and carboxylic acid groups. The higher O/C, H/C and N/C ratios of YHA can be assigned to the low aromatization degree. A study of interaction between Ni(II), Zn(II), Cd(II) and humic acids (HAs) at different metal-ligand ratios has been made by conductimetric and fluorescence techniques. The results obtained by the conductimetry method are interpreted using an excess function (Δk), which related the conductivity of the mixture and of the separated components. A positive value of this function is obtained. It indicates the complexation of HAs with metallic ions. The association degree of the heavy metals (M) with both HAs was in the following order: Ni > Zn > Cd and the binding capacity of PCHA is smaller than that of YHA. A fluorescence titration method and a single site model were used for determining metal ion complexing capacities (CCM) and stability constants (log KM) of YHA and PCHA complexes. Titration of HAs with metal ions at pH 7 and ionic strength 0.1 mol/L resulted in a marked decrease of fluorescence intensities of untreated HAs. The quenching constants (KSV) between HAs and M are obtained in terms of Stern-Volmer analysis. KSV show that the YHA binds the higher amount metals than PCHA. CCM of YHA calculated by MATLAB program were higher than those of PCHA and other natural HAs found in the literature at pH 7. Based on these results, YHA may play the role of a biocaptor of polluting metals. [ABSTRACT FROM AUTHOR]