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The use of chiral organic ligands as linkers and metal ion nodes with specific coordination geometry is an effective strategy for creating homochiral structures with potential ferroelectric properties. Natural Cinchona alkaloids, e.g., quinine and cinchonine, as compounds with a polar quinuclidine fragment and aromatic quinoline ring, are suitable candidates for the construction of molecular ferroelectrics. In this work, the compounds [CnZnCl3]·MeOH and [CnZnBr3]·MeOH, which crystallize in the ferroelectric polar space group P21, were prepared by reacting the cinchoninium cation (Cn) with zinc(II) chloride or zinc(II) bromide. The structure of [CnZnBr3]·MeOH was determined from single-crystal X-ray diffraction analysis and was isostructural with the previously reported chloride analog [CnZnCl3]·MeOH. The compounds were characterized by infrared spectroscopy, and their thermal stability was determined by thermogravimetric analysis and temperature-modulated powder X-ray diffraction experiments. The intermolecular interactions of the different cinchoninium halogenometalate complexes were evaluated and compared. [ABSTRACT FROM AUTHOR]

Three bis(imidazo[1,5‐a]pyridine)methane derivatives (bis(1‐methylimidazo[1,5‐a]pyridin‐3‐yl)methane, LH; 3,3'‐(ethane‐1,1‐diyl)bis(1‐methylimidazo[1,5‐a]pyridine) LMe; 3,3'‐(2‐phenylethane‐1,1‐diyl)bis(1‐methylimidazo[1,5‐a]pyridine), LBz) have been synthesized, and fully characterized in solution (1H and 13C NMR spectra) and in the solid state (X‐ray). In particular, LH has been prepared in high yield (75 %) under very mild conditions (water, 60 °C), offering an alternative route to those reported in the literature. LMe and LBz have been obtained from LH by functionalization of the methylene bridge. The bis(imidazo[1,5‐a]pyridine)methane compounds have been coordinated to a zinc(II) center, leading to tetrahedral complexes of general formula [Zn(LR)2](ClO4)2 (R=H, Me, Bz), which showed a bright fluorescent emission with (x,y) color coordinates very close to standard blue. TD‐DFT have been employed to describe the Frontier Molecular Orbitals (FMOs) participating in electronic transitions, highlighting the main transition as 1(π‐π*) transition in the bis(imidazo[1,5‐a]pyridine)methane and a mixed intra‐ligand (1ILT) and ligand‐to‐ligand (1LLT) transition in the complexes. [ABSTRACT FROM AUTHOR]

The hydrophobic reagent 6-hexyl-4-(2-thiazolylazo)resorcinol (HTAR) was investigated as part of a cloud-point extraction (CPE) system for the spectrophotometric determination of Zn(II). In the system, complexes with different stoichiometries, including 1:1 and 2:2 (Zn:HTAR), are formed. Their ground-state equilibrium geometries were optimized at the B3LYP/6-31G level of theory. The obtained structures were then used to calculate vertical excitation energies in order to generate theoretical UV/Vis absorption spectra. The comparison between theoretical and experimental spectra demonstrated that, under optimal conditions, a binuclear complex containing oxygen-bridging atoms is the dominant species. The absorbance was found to be linearly dependent on the concentration of Zn(II) within the range of 15.7 to 209 ng mL−1 (R2 = 0.9996). The fraction extracted (%E), logarithm of the conditional extraction constant (log Kex), and molar absorption coefficient (ε) at λmax = 553 nm were calculated to be 98.3%, 15.9, and 4.47 × 105 L mol−1 cm−1, respectively. The method developed is characterized by simplicity, convenience, profitability, sensitivity, and ecological friendliness. It has been successfully applied to the analysis of pharmaceutical and industrial samples. [ABSTRACT FROM AUTHOR]

Two new coordination compounds of zinc(II) with diethylmalonic acid anions (Et2mal2–) and 4,4'-bipyridine (4,4'-bipy) are synthesized: {[Zn(H2O)(4,4'-bipy)(Et2mal)]·0.5C2H5OH·1.5H2O}n (I) and {[Zn4(H2O)2(4,4'-bipy)3(Et2mal)4]·6H2O}n (II). According to the XRD data (CIF files CCDC nos. 2323336 (I) and 2323337 (II)), both compounds are 2D polymers with the sql and bey topology, respectively. The choice of the initial zinc salt and solvent predetermines the compositions and structures of the polymers under similar synthesis conditions. [ABSTRACT FROM AUTHOR]

The complex, trichlorido(1,4,11-triaza-8-azoniatetracyclo[6.6.2.04,16.011,15]hexadecane 1-oxide-κO)zinc(II) monohydrate, [ZnCl3(C12H23N4O)]·H2O, (I), has monoclinic symmetry (space group P21/n) at 120 K. The zinc(II) center adopts a slightly distorted tetrahedral coordination geometry and is coordinated by three chlorine atoms and the oxygen atom of the oxidized tertiary amine of the tetracycle. The amine nitrogen atom, inside the ligand cleft, is protonated and forms a hydrogen bond to the oxygen of the amine oxide. Additional hydrogen-bonding interactions involve the protonated amine, the water solvate oxygen atom, and one of the chloro ligands.

Reacting trimesic acid (H3TMA, C9H6O6) with CaCl2 and MCl2 at 110 °C under hydrothermal conditions gave the isostructural heterobimetallic coordination polymers (CPs) catena‐poly[[tetraaquazinc(II)]‐μ‐5‐carboxybenzene‐1,3‐dicarboxylato‐[tetraaquacalcium(II)]‐μ‐5‐carboxybenzene‐1,3‐dicarboxylato], [CaZn(HTMA)2(H2O)8]n, 1, and catena‐poly[[tetraaquacobalt(II)]‐μ‐5‐carboxybenzene‐1,3‐dicarboxylato‐[tetraaquacalcium(II)]‐μ‐5‐carboxybenzene‐1,3‐dicarboxylato], [CaCo(HTMA)2(H2O)8]n, 2. Compounds 1 and 2 crystallize in the monoclinic space group C2/c. The solid‐state structures consist of eight‐coordinate CaII ions and six‐coordinate MII ions. These ions are connected by a doubly deprotonated HTMA2− ligand to create a one‐dimensional (1D) zigzag chain. Poly[[decaaquabis(μ3‐benzene‐1,3,5‐tricarboxylato)calcium(II)dizinc(II)] dihydrate], {[CaZn2(TMA)2(H2O)10]·2H2O}n, 3, was found incidentally as a minor by‐product during the synthesis of 1 at a temperature of 140 °C. It forms crystals in the orthorhombic space group Ccce. The structure of 3 consists of a two‐dimensional (2D) layer composed of [Zn(TMA)] chains that are interconnected by CaII ions. The presence of aromatic carboxylic acid ligands and water molecules, which can form numerous hydrogen bonds and π–π interactions, increases the stability of the three‐dimensional (3D) supramolecular architecture of these CPs. Compounds 1 and 2 exhibit thermal stability up to 420 °C, as indicated by the thermogravimetric analysis (TGA) curves. The powder X‐ray diffraction (PXRD) data reveal the formation of unidentified phases in methanol and dimethyl sulfoxide, while 1 exhibits chemical stability in a wide range of solvents. The luminescence properties of 1 dispersed in various low molecular weight organic solvents was also examined. The results demonstrate excellent selectivity, sensitivity and recyclability for detecting acetone molecules in aqueous media. Additionally, a possible sensing mechanism is also outlined. [ABSTRACT FROM AUTHOR]

Novel heterobimetallic complexes of type [Zn(L)2M2(R)4Cl2], where M = Sn(IV) and Si(IV); R = –CH3 and –C6H5, were prepared by reacting the methanolic solution of monometallic complex [Zn(L)2Cl2] with group fourteen organometallic dichloride [(CH3)2SnCl2/(C6H5)2SnCl2/(CH3)2SiCl2/(C6H5)2SiCl2]. The structures of the obtained complexes were identified by various spectrometric methods such as Fourier transformation infra-red (FT-IR), nuclear magnetic resonance (NMR), electrospray ionization mass spectrometry, powder X-ray diffraction, molar conductivity, and UV–Vis. Density functional theory (DFT) calculations were performed to explore the quantum chemical properties of the newly designed Zn(II) complexes. In vitro antimicrobial, anti-inflammatory, and anticancer activities of Schiff base ligand [L], mononuclear complex [Zn(L)2Cl2] and its corresponding heterobimetallic complexes, [Zn(L)2M2(R)4Cl2], were evaluated. The heterobimetallic complexes exhibited higher activities against Gram-positive bacteria (Bacillus Subtilis and Bacillus cereus), Gram-negative bacteria (Xanthomonas Campestris and Pseudomonas aeruginosa), and fungal strains (Aspergillus flavus and Fusarium oxysporum) in comparison with both the Schiff base ligand and the monometallic complex. This enhanced performance of the heterobimetallic complexes can be attributed to the synergistic effect. The heterobimetallic complex [Zn(L)2Sn2(C6H5)4Cl2] showed the highest potential of inflammation inhibition with IC50 = 5.2 µg/mL, very close to standard drug sodium diclofenac (IC50 = 4.59 µg/mL). Furthermore, the synthesized compounds were assessed for their anticancer activity against three cell lines: human colon (HCT-116), human breast (MDA-MB-231), and human lung cancer cells (A549) using the MTT assay. The obtained results showed that the heterobimetallic complex [Zn(L)2Sn2(C6H5)4Cl2] displayed the highest cytotoxic activity (IC50 = 3.12 ± 0.25, 3.72 ± 0.26, and 3.94 ± 0.14 for HCT-116, MDA-MB-231 and A549, respectively). These findings suggest that the newly formulated metal complexes could be explored further in the pursuit of drug development. [ABSTRACT FROM AUTHOR]

Two Zn(II) complexes, referred to as helicate 1 and helicate 2, were synthesized using subcomponent self-assembly of zinc(II) trifluoromethanesulfonate (Zn(CF3SO3)2), 2,4,6-tris(3-aminophenoxy)triazine, and either 2-formylpyridine or 3-methyl-2-pyridinecarboxaldehyde in CH3CN solution. The triangular helicate structure of both complexes was verified by 1H NMR and ESI–MS measurements, and the host–guest interactions between the helicates and a number of guest molecules were investigated. It was discovered that the effect of the host–guest interactions significantly changed when the aldehyde component was replaced by 3-methyl-2-pyridinecarboxaldehyde, which suggested that the guest-binding sites may occur around the peripheral apertures of the complex. Additionally, the binding behaviour between helicate 1 and tetraphenylborate guests was further investigated, which allowed for the quantification of the host–guest stoichiometry in a 1:2 ratio. [ABSTRACT FROM AUTHOR]

The title complex, [ZnCl(C12H15N3O2)2][ZnCl3(CH3CN)], was synthesized and its structure was fully characterized through single-crystal X-ray diffraction analysis. The complex crystallizes in the orthorhombic system, space group Pbca (61), with a central zinc atom coordinating one chlorine atom and two pyrrolidinyl-4-methoxyphenyl azoformamide ligands in a bidentate manner, utilizing both the nitrogen and oxygen atoms in a 1,3-heterodiene (N=N—C=O) motif for coordinative bonding, yielding an overall positively (+1) charged complex. The complex is accompanied by a [(CH3CN)ZnCl3]− counter-ion. The crystal data show that the harder oxygen atoms in the heterodiene zinc chelate form bonding interactions with distances of 2.002 (3) and 2.012 (3) Å, while nitrogen atoms are coordinated by the central zinc cation with bond lengths of 2.207 (3) and 2.211 (3) Å. To gain further insight into the intermolecular interactions within the crystal, Hirshfeld surface analysis was performed, along with the calculation of two-dimensional fingerprint plots. This analysis revealed that H...H (39.9%), Cl...H/H...Cl (28.2%) and C...H/H...C (7.2%) interactions are dominant. This unique crystal structure sheds light on arrangement and bonding interactions with azoformamide ligands, and their unique qualities over similar semicarbazone and azothioformamide structures.

The use of chiral organic ligands as linkers and metal ion nodes with specific coordination geometry is an effective strategy for creating homochiral structures with potential ferroelectric properties. Natural Cinchona alkaloids, e.g., quinine and cinchonine, as compounds with a polar quinuclidine fragment and aromatic quinoline ring, are suitable candidates for the construction of molecular ferroelectrics. In this work, the compounds [CnZnCl3]·MeOH and [CnZnBr3]·MeOH, which crystallize in the ferroelectric polar space group P21, were prepared by reacting the cinchoninium cation (Cn) with zinc(II) chloride or zinc(II) bromide. The structure of [CnZnBr3]·MeOH was determined from single-crystal X-ray diffraction analysis and was isostructural with the previously reported chloride analog [CnZnCl3]·MeOH. The compounds were characterized by infrared spectroscopy, and their thermal stability was determined by thermogravimetric analysis and temperature-modulated powder X-ray diffraction experiments. The intermolecular interactions of the different cinchoninium halogenometalate complexes were evaluated and compared.

The complex, trichlorido(1,4,11-triaza-8-azoniatetracyclo[6.6.2.04,16.011,15]- hexadecane 1-oxide-κO)zinc(II) monohydrate, [ZnCl3(C12H23N4O)]⋅H2O, (I), has monoclinic symmetry (space group P21/n) at 120 K. The zinc(II) center adopts a slightly distorted tetrahedral coordination geometry and is coordinated by three chlorine atoms and the oxygen atom of the oxidized tertiary amine of the tetracycle. The amine nitrogen atom, inside the ligand cleft, is protonated and forms a hydrogen bond to the oxygen of the amine oxide. Additional hydrogen-bonding interactions involve the protonated amine, the water solvate oxygen atom, and one of the chloro ligands. [ABSTRACT FROM AUTHOR]

A new complex formed from the reaction of benzene-1,2,4,5-tetracarboxylic dianhydride with zinc(II) acetate dihydrate was synthesized and characterized by single-crystal X-ray diffraction, thermal analysis (TGA), and density functional theory (DFT). [C10H4O8][Zn(H2O)6] (1), crystallized in a monoclinic system with space group P2/m. Theoretical modeling was performed at the DFT/B3LYP computational level with 6–311 G(d,p) and LanL2DZ basis sets. The Zn(II) is six-coordinate, forming an ideal octahedral geometry. A Hirshfeld surface analysis of the complex indicated that H···O/O···H contacts contribute to 47.8% of the crystal packing. The stability of 1 was investigated by determining the global chemical reactivity descriptors (GCRD). The nonlinear optical (NLO) behavior was investigated by analyzing the dipole moment, polarizability, and first-order hyperpolarizability (μ, α and β) via a theoretical approach, indicating that 1 has important nonlinear optical properties. A molecular docking study shows binding of 1 on the active site of receptors from human cyclooxygenase-2 enzyme (PDB code: 5IKT) and Escherichia coli MenB (PDB code: 3T88). [ABSTRACT FROM AUTHOR]

The two enantiomers of chiral phosphonate 4-phenyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepine 4-oxide, O=PPh(BINOL), were synthesized from the proper 1,1′-bi-2-naphtol (BINOL) enantiomer and characterized. The structure of the (S)-enantiomer was elucidated by means of single-crystal X-ray diffraction. The reaction with anhydrous ZnBr2 afforded complexes having the general formula [ZnBr2{O=PPh(BINOL)}2] that showed intense fluorescence centered in the near-UV region rationalized on the basis of TD-DFT calculations. The corresponding Mn(II) complexes with the general formula [MnX2{O=PPh(BINOL)}2] (X = Cl, Br) exhibited dual emission upon excitation with UV light, with the relative intensity of the bands dependent upon the choice of the halide. The highest energy transition is comparable with that of the Zn(II) complex, while the lowest energy emission falls in the red region of the spectrum and is characterized by lifetimes in the hundreds of microseconds range. Although the emission at lower energy can also be achieved by direct excitation of the metal center, the luminescence decay curves suggest that the band in the red range is possibly derived from BINOL-centered excited states populated by intersystem crossing. [ABSTRACT FROM AUTHOR]

The title complex, [ZnCl(C12H15N3O2)2][ZnCl3(CH3CN)], was synthesized and its structure was fully characterized through single-crystal X-ray diffraction analysis. The complex crystallizes in the orthorhombic system, space group Pbca (61), with a central zinc atom coordinating one chlorine atom and two pyrrolidinyl-4-methoxyphenyl azoformamide ligands in a bidentate manner, utilizing both the nitrogen and oxygen atoms in a 1,3-heterodiene (N N--C O) motif for coordinative bonding, yielding an overall positively (+1) charged complex. The complex is accompanied by a [(CH3CN)ZnCl3]- counter-ion. The crystal data show that the harder oxygen atoms in the heterodiene zinc chelate form bonding interactions with distances of 2.002 (3) and 2.012 (3) A °, while nitrogen atoms are coordinated by the central zinc cation with bond lengths of 2.207 (3) and 2.211 (3) A. To gain further insight into the intermolecular interactions within the crystal, Hirshfeld surface analysis was performed, along with the calculation of two-dimensional fingerprint plots. This analysis revealed that H. . .H (39.9%), Cl. . .H/H. . .Cl (28.2%) and C. . .H/H. . .C (7.2%) interactions are dominant. This unique crystal structure sheds light on arrangement and bonding interactions with azoformamide ligands, and their unique qualities over similar semicarbazone and azothioformamide structures. [ABSTRACT FROM AUTHOR]

The hydrophobic reagent 6-hexyl-4-(2-thiazolylazo)resorcinol (HTAR) was investigated as part of a cloud-point extraction (CPE) system for the spectrophotometric determination of Zn(II). In the system, complexes with different stoichiometries, including 1:1 and 2:2 (Zn:HTAR), are formed. Their ground-state equilibrium geometries were optimized at the B3LYP/6-31G level of theory. The obtained structures were then used to calculate vertical excitation energies in order to generate theoretical UV/Vis absorption spectra. The comparison between theoretical and experimental spectra demonstrated that, under optimal conditions, a binuclear complex containing oxygen-bridging atoms is the dominant species. The absorbance was found to be linearly dependent on the concentration of Zn(II) within the range of 15.7 to 209 ng mL−1 (R2 = 0.9996). The fraction extracted (%E), logarithm of the conditional extraction constant (log Kex), and molar absorption coefficient (ε) at λmax = 553 nm were calculated to be 98.3%, 15.9, and 4.47 × 105 L mol−1 cm−1, respectively. The method developed is characterized by simplicity, convenience, profitability, sensitivity, and ecological friendliness. It has been successfully applied to the analysis of pharmaceutical and industrial samples.

A variety of di- and poly-nuclear zinc(II) complexes with salicylaldehyde-based azine ligands have been synthesized and their structures and properties have been reported. This review represents an overview on properties of these complexes. The synthesis and structures of the complexes are also discussed briefly. Only complexes are considered in this review whose X-ray structures are available. Different methods of synthesizing di- and poly-nuclear complexes are discussed. The structures of the complexes and magnetic properties are compared. The less explored areas of potential applications of these complexes are also highlighted. [ABSTRACT FROM AUTHOR]

In the present study, a zinc(II) complex with 4-ethynyl-2,2'-bipyridine (ebpy), [Zn(ebpy)Cl2], was synthesized and characterized by spectroscopic (¹H-NMR, IR and UV-Vis) methods and molar conductivity measurement. The crystal structure of the [Zn(ebpy)Cl2] complex was determined by single-crystal X-ray diffraction analysis, confirming the bidentate coordination of the ebpy ligand through its two nitrogen atoms, while the remaining two coordination sites are occupied by two chloride ions. With the aim to investigate the reactivity of the synthesized zinc(II) complex toward biologically important molecules, its binding affinity to calf thymus DNA (ct-DNA) and bovine serum albumin (BSA) was studied by fluorescence emission spectroscopy. From the obtained results, it can be concluded that [Zn(ebpy)Cl2] complex binds to bovine serum albumin reversibly, while the combination of ethidium bromide (EthBr) and Hoechst 33258 (2'-(4-hydroxyphenyl)-5-[5-(4-methylpiperazine-1-yl)benzimidazo-2-yl]-benzimidazole) competitive binding study suggests that this complex interacts with ct-DNA through the minor groove binding, which is in agreement with molecular docking study. [ABSTRACT FROM AUTHOR]

A final review of the results of studies of versatile biological activities (in vitro) of chiral metal complexes with benzylamine and ethylenediamine derivatives of terpenes is presented. The cytotoxic profiles of palladacycles containing a Pd–C bond and palladium and zinc chelate complexes were determined. For a number of compounds, the possible mechanisms of potential anticancer action were analyzed, such as modulation of mitochondrial functioning and effect on the parameters of glycolytic function of tumor cells. The antibacterial and antifungal activities of palladium complexes of different types and copper chelate complexes were investigated. A correlation between high antimicrobial activity and antioxidant properties was found for a number of copper complexes. The material is supplemented by an extended analysis of publications in relevant subjects. [ABSTRACT FROM AUTHOR]

A mixed-ligand zinc(II) complex, [Zn(Hpma)(phen)Cl] (where Hpma- = N-(2,6-dimethylphenyl)oxamate and phen = 1,10-phenanthroline), has been prepared by the reaction of zinc chloride, ethyl (2,6-dimethylphenylcarbamoyl)formate (Hdmp) and 1,10-phenanthroline under basic conditions in dimethylformamide. The structure of the complex was characterised by elemental analysis, IR, 1H-NMR, UV-Vis absorption and X-ray crystallography. The metal complex crystallises in the monoclinic system (space group P21/c) and is composed of the five-coordinate zinc ion in a distorted spherical square pyramidal geometry. Stabilisation of single crystals occurs through hydrogen bonds and p-p stacking interactions. [ABSTRACT FROM AUTHOR]

A series of Schiff base derivatives, namely N-(4-methoxyphenyl)-1-(1-methylbenzimidazol-2-yl)methanimine (L1), 4-methoxy-N-[(1-methylbenzimidazol-2-yl)methyl]aniline (L2), and 2-[(E)-(1-propylbenzimidazol-2-yl)iminomethyl]phenol (L3), were synthesized. These compounds feature different linker groups, including –CH=N–, –CH2–NH–, and –N=CH–, respectively. During the process of zinc(II) and cadmium(II) complexation in the presence of the closo-dodecaborate [B12H12]2– anion, it was observed that ligand L3 underwent degradation. Consequently, two compounds were isolated, [Zn(Bz-NH2)2(CH3COO)2] and (HBz-NH2)2[B12H12]∙2CH3CN, both containing 1-propyl-2-aminobenzimidazole (Bz-NH2), which is a degraded fragment of the ligand. Several new zinc(II) and cadmium(II) coordination compounds were synthesized and characterized using various physicochemical analysis methods, including elemental analysis, IR, and UV spectroscopy. Additionally, X-ray diffraction and Hirshfeld surface analysis were performed for compounds [Cd(L2)2(CH3CN)(H2O)][B12H12], [Zn(Bz-NH2)2(CH3COO)2], and (HBz-NH2)2[B12H12]∙2CH3CN, as well as for ligand L2. [ABSTRACT FROM AUTHOR]

The present study reports on a 2D lamellar coordination polymer (CP) of {[Zn(µ3-pmdc)(H2O)]·H2O}n formula (pmdc = pyrimidine-4,6-dicarboxylate). This CP is synthesized under an appropriate acid-base reaction between the gently mortared reagents in the solid state through a solvent-free procedure that avoids the presence of concomitant byproducts. The X-ray crystal structure reveals the occurrence of Zn2 entities connected through carboxylate groups of pmdc, which behave as triconnected nodes, giving rise to six-membered ring-based layers that are piled up through hydrogen bonding interactions. In addition to a routine physico-chemical characterization, the thermal evolution of the compound has been studied by combining thermogravimetric and thermodiffractometric data. The photoluminescence properties are characterized in the solid state and the processes governing the spectra are described using time-dependent density-functional theory (TD-DFT) with two different approaches employing different program packages. The emissive capacity of the material is further analyzed according to the dehydration and decreasing temperature of the polycrystalline sample. [ABSTRACT FROM AUTHOR]

A complex of zinc(II) with 2-hydroxy-5-ethylphenylphosphonic acid (H3L) of the composition [Zn(H2L)2(Н2О)2][Zn(HL)(Н2О)]·H2O (I) was synthesized, the structure of which was established based on data of X-ray diffraction and elemental analysis, quantum chemical calculations, as well as IR and electron absorption spectroscopies. The stability constants of H3L acid complexes with zinc(II) perchlorate in water were determined by potentiometric titration. The cytotoxic properties of H3L acid and complex I were studied for the first time on HeLa cells (human cervical adenocarcinoma). The results on the accumulation of complex I in HeLa cells were obtained by laser confocal microscopy. [ABSTRACT FROM AUTHOR]

Aminopolycarboxylate zinc(II) complexes with 1,10-phenanthroline and 2,2′-bipyridyl {[Zn(IDA)(H2O)2], [Zn(IDA)(bipy)(H2O)]·2H2O and [Zn(IDA)(phen)(H2O)]·2H2O} were synthesized. In order to confirm the composition and purity of the synthesized complex compounds, elemental analysis was used. Next, the kinetics of the substitution reaction of two water molecules in the zinc(II) iminodiacetate complex for 1,10-phenanthroline and 2,2′-bipyridyl in two surfactant solvents: CTAB and Triton X-100 were investigated. The kinetic studies were carried out using the stopped flow method. The kinetic research were carried out at 3 different temperatures: 288.15, 293.15 and 298.15 K and at different molar concentrations of the complex compound [Zn(IDA)(H2O)2]: 1 mM; 0.75 mM, 0.5 mM and 0.25 mM and at a constant molar concentration of ligands: i.e. 1,10-phenanthroline and 2,2′-bipyridyl, were 0.05 mM. Changes in absorbance during the kinetic run of the tested reactions were measured at a wavelength of 260 nm. Thanks to the conducted kinetic studies, the order of the reaction was determined, and the observable rate constants of the reaction rates of the substitution of two aqua molecules into the N-donor ligand were determined by the stopped—flow method using the Glint program. In the next step the thermodynamic parameters of complexes: {[Zn(IDA)(H2O)2], [Zn(IDA)(bipy)(H2O)]·2H2O and [Zn(IDA)(phen)(H2O)]·2H2O} in aqueous solutions by use potentiometric titrations were determined. The Hyperquad2018 program was used for determining of stability constants. In addition, the stoichiometry of complexes of zinc(II) with N-heterocyclic ligands in aqueous solutions was determined using the conductometric titrations. [ABSTRACT FROM AUTHOR]

A combination of 4-styrylpyridine (spy) and 1-adamantanecarboxylic acid (Hadc) was employed in the assembly reactions with Zn(II) and Cu(II) nitrates. The photoreactivity of the products was compared and discussed on the basis of the structure–function relationship. Zinc(II) complex 1 is a trinuclear species of type [Zn3(spy)2(adc)6] in which three zinc(II) atoms are linearly arranged, with two adjacent zinc(II) atoms linked by three bridging carboxylates. Two spy ligands occupy both terminal positions, yielding the overall structure of a six-bladed windmill. Copper(II) complex 2, [Cu(spy)2(adc)2][Cu2(spy)2(adc)4]·2DMF, is an inorganic cocrystal comprising a mononuclear complex with a trans square planar geometry and a dinuclear complex with a paddle-wheel structure. In the photoreaction experiments characterized by 1H NMR spectroscopy, the zinc(II) complex was found to be photoinert, while the copper(II) complex was photoreactive to form a cyclobutene ring via the [2+2] photodimerization between two spy ligands, resulting in the preparation of a one-dimensional chain as a coordination polymer. The separations of the C=C bond pair obtained from the crystal structures for both products also support their photoreactivity. For example, the spy ligands from two adjacent monocopper(II) complexes are aligned in a head-to-tail manner with the separation of 3.899 Å between the C=C bond pair, satisfying the so-called Schmidt criteria (<4.2 Å). However, no other products satisfy this condition. [ABSTRACT FROM AUTHOR]

The equilibria of the complex formation between the anionic chelate of zinc(II) with the tridentate ligand of 4-(2-pyridylazo)-resorcinol (PAR) and the bulky organic tetrazolium cation of 3-(2-naphtyl)-2,5-diphenyl-2Htetrazolium chloride (TV) in the liquid-liquid extraction system Zn(II)-PAR-TV-H2O-2-methyl-1-propanol was studied by spectrophotometric method. The molar ratio of the reagents was determined by independent methods under the optimum condition for ion-association and for extraction. The validity of Beer's law was checked and some analytical characteristics were calculated. The constants, describing the association process in aqueous phase and the extraction equilibria, were calculated. Based on this, a reaction scheme, a general formula and a structural formula of the complex were suggested. The zinc(II) cation is six coordinated with the tridentate ligand through the following atoms: the azo nitrogen, the pyridine nitrogen and the oxygen atom from the phenolic group, which is in ortho position relative to the azo group, each of them forming two five-membered chelate rings. [ABSTRACT FROM AUTHOR]

In recent years, many more chemists have been focused on fluorescent probe research, and significant progresses, which has been made in terms of design and use. This review begins with a brief overview of the most prevalent chemosensor design concepts, followed by a discussion of the photophysical characteristics of the 1,8-naphthalimide structure, such as great photostability, high fluorescence quantum yield and ease of modification which has been used in Zn2+ cation sensing to date. The contributions of the fluorescent probes built on the 1,8-naphthalimide based platform in the field of chemical sensing, biological sensing, pharmaceutical chemistry, environment and food safety in the last 10 years are then systematically introduced by discussing the probe's fluorescence behavior in the corresponding recognition process. Simultaneously, we intend to build an overall review on fluorescent chemical sensor that will be able to play larger and more interesting role in the future. [ABSTRACT FROM AUTHOR]

Bu çalışmada, üç-dişli bis-benzimidazol piridin türevi ligant (L) ve bu ligantın nötr Zn(II) kompleksi [ZnLCl2] sentezlendi. Elde edilen bu yeni koordinasyon bileşiğinin yapısı aydınlatılarak, elektrokimyasal özellikleri araştırıldı. Moleküllerin yapısal karakterizasyonunda çeşitli spektroskopik yöntemler (FT-IR, 1H NMR, 13C NMR, MALDI-TOF-MS, UV-Vis gibi) kullanıldı. Elektrokimyasal özellikleri ise DMF içerisinde dönüşümlü voltametri (CV) tekniği ve kare dalga voltametrisi kullanılarak araştırıldı. Tarama hızı ve pik akımı arasındaki ilişki kullanılarak kompleksin elektrokimyasal mekanizması aydınlatılmış, kompleksin yarı-tersinir ve difüzyon kontrollü bir davranış sergilediği ortaya konulmuştur. Bu nedenle, kompleksin özellikle de redoks akışlı piller, güneş pilleri ve elektrokataliz gibi alanlarda uygulanabileceği düşünülmektedir.

The two enantiomers of chiral phosphonate 4-phenyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepine 4-oxide, O=PPh(BINOL), were synthesized from the proper 1,1′-bi-2-naphtol (BINOL) enantiomer and characterized. The structure of the (S)-enantiomer was elucidated by means of single-crystal X-ray diffraction. The reaction with anhydrous ZnBr2 afforded complexes having the general formula [ZnBr2{O=PPh(BINOL)}2] that showed intense fluorescence centered in the near-UV region rationalized on the basis of TD-DFT calculations. The corresponding Mn(II) complexes with the general formula [MnX2{O=PPh(BINOL)}2] (X = Cl, Br) exhibited dual emission upon excitation with UV light, with the relative intensity of the bands dependent upon the choice of the halide. The highest energy transition is comparable with that of the Zn(II) complex, while the lowest energy emission falls in the red region of the spectrum and is characterized by lifetimes in the hundreds of microseconds range. Although the emission at lower energy can also be achieved by direct excitation of the metal center, the luminescence decay curves suggest that the band in the red range is possibly derived from BINOL-centered excited states populated by intersystem crossing.

Zinc(II) bis(3-aminiumpropylsilsesquioxane)(1-hydroxyethylidene)diphosphonate tetrahydrate and manganese(II) bis(3-aminiumpropylsilsesquioxane)(1-hydroxyethylidene)diphosphonate trihydrate were obtained by the reactions of aqueous solution of 3-aminopropyltriethoxysilane with (1-hydroxyethylidene)diphosphonates of zinc(II) H2ZnL·2H2O and manganese(II) H2MnL·3H2O. The synthesized compounds were studied by the methods of elemental, thermal, and X-ray phase analysis, IR spectroscopy, and scanning electron microscopy. The specific surface areas of the initial xerogels and products of their thermal decomposition were measured. [ABSTRACT FROM AUTHOR]

A complex [Zn(bpy)(acr)2]·H2O (1) was converted in a DMF medium (DMF = N,N′-dimethylformamide) into a coordination polymer [Zn(bpy)(acr)(HCOO)]n (1a) (bpy = 2,2′-bipyridine, and Hacr = acrylic acid), and the species was fully characterized through a single crystal X-ray diffraction. Additional data were obtained by IR and thermogravimetric analysis. Complex (1a) crystalized the coordination polymer in the space group Pca21 of an orthorhombic system. Structural characterization revealed that Zn(II) adopted a square pyramidal stereochemistry generated by bpy molecules, coordinated by chelate, acrylate, and formate ions as unidentate and bridged, respectively. The presence of both the formate and the acrylate with different coordination modes generated two bands in ranges that were characteristic for the carboxylate vibration modes. Thermal decomposition occurs in two complex steps: it first happens via a bpy release, which is followed by an overlapped process that is associated with acrylate and formate decomposition. The obtained complex is of present interest due to the presence of two different carboxylates in its composition and situation, which is rarely reported in the literature. [ABSTRACT FROM AUTHOR]

A polymeric inclusion membrane (PIM) consisting of matrix CTA (cellulose triacetate), ONPPE (o-nitrophenyl pentyl ether) and phosphonium salts (Cyphos 101, Cyphos 104) was used for separation of Cu(II), Zn(II) and Ni(II) ions. Optimum conditions for metal separation were determined, i.e., the optimal concentration of phosphonium salts in the membrane, as well as the optimal concentration of chloride ions in the feeding phase. On the basis of analytical determinations, the values of parameters characterizing transport were calculated. The tested membranes most effectively transported Cu(II) and Zn(II) ions. The highest recovery coefficients (RF) were found for PIMs with Cyphos IL 101. For Cu(II) and Zn(II), they are 92% and 51%, respectively. Ni(II) ions practically remain in the feed phase because they do not form anionic complexes with chloride ions. The obtained results suggest that there is a possibility of using these membranes for separation of Cu(II) over Zn(II) and Ni(II) from acidic chloride solutions. The PIM with Cyphos IL 101 can be used to recover copper and zinc from jewellery waste. The PIMs were characterized by AFM and SEM microscopy. The calculated values of the diffusion coefficient indicate that the boundary stage of the process is the diffusion of the complex salt of the metal ion with the carrier through the membrane. [ABSTRACT FROM AUTHOR]

The cloud point extraction technique has become increasingly popular in recent years for trace metal separation and preconcentration. When heated to a specific temperature, cloud point extraction utilizes the property of nonionic surfactants in aqueous solutions to generate micelles and become turbid (so-called cloud point temperature). For analytical chemists, developing a simple and selective technology for the separation and determination of metals and medicinal drugs is a critical concern. Therefore, a sensitive, accurate, and green cloud point extraction (CPE) procedure was developed for the micro-determination of metal cations like zinc (II) and cadmium (II) in food samples. Triton X–114 and 1-(4-(Phenyldiazenyl) phenyl) azo naphthalene-2-ol (Sudan III) were used as extractants. Sudan III forms an ionpair association complex with metal ions when the pH is 9. In the presence of 5 ppm zinc (II) or 4 ppm cadmium (II) in an aqueous solution, the maximum extraction efficiency should be achieved. In order to create Cloud Point Temperature (CPT) quantitatively, the extraction applications in this approach required heating at 85°C for 20 minutes. In this work, the impacts of different surfactants, pH, stoichiometry, and various organic reagents on interferences as well as spectrophotometric determination were explored. The linearity ranges of zinc (II) and cadmium (II) were 0.25-700 and 0.25-400 ppm, respectively. The results show low detection limits of 0.035 and 0.042 ppm for zinc (II) and cadmium (II), respectively. Also, the quantification limits for zinc (II) and cadmium (II) are 0.116 and 0.140 ppm, respectively. [ABSTRACT FROM AUTHOR]

Three new ZnII complexes with the ligand 4′-chloro-2,2′:6′,2ʺ-terpyridine (4′-Cltpy), [Zn(4′-Cltpy)(N3)2] (1), [Zn(4′-Cltpy)(NCS)2] (2) (two 1:1 metal/ligand complexes) and a 1:2 metal/ligand complex, [Zn(4′-Cltpy)2](NO3)2·2H2O (3), have been synthesized and characterized by elemental analysis, IR, 1H NMR spectroscopy and single-crystal X-ray diffraction. The structures of 1 and 2 contain a ZnN5 coordination sphere, which includes coordination from three nitrogen donors of the 4′-Cltpy ligand and two nitrogen atoms of two terminal azide or two terminal thiocyanate ligands, respectively. Addison's τ value suggests a distorted square pyramidal coordination of ZnII in 1 and intermediate between square pyramidal and trigonal bipyramidal in 2. In the complex cation of 3, the ZnII center is coordinated by six nitrogen atoms from two 4′-Cltpy ligands in a distorted octahedral coordination geometry. In this structure, two non-coordinating nitrate anions serve as counterions, and there are two non-coordinating solvent water molecules. Hirshfeld surface analysis was employed to clarify the nature and extent of intermolecular interactions. In addition, the thermal stabilities of the compounds were evaluated by thermogravimetric analysis (TGA). [ABSTRACT FROM AUTHOR]

Strontium(II)—zinc(II) and strontium(II)—cadmium(II) coordination compounds with dianions of cyclobutane-1,1-dicarboxylic acid (H2cbdc) were synthesized. In the complexes [Sr4Zn4(cbdc)8(H2O)9]n(1) and {[SrCd(cbdc)2(H2O)3] · 3H2O}n(2), the cyclobutane-1,1-dicarboxylate dianions are coordinated to strontium atoms in a chelate fashion to form monomeric mono- and bischelate moieties, which link the d-metal atoms into a polymer structure. An increase in the ion radius of the d-metal in going from zinc(II) to cadmium(II) is accompanied by a decrease in the dimensionality of the coordination polymer from layered to chain. [ABSTRACT FROM AUTHOR]

Synopsis on Cu(II)-M(II) (M = Zn, Cd and Hg) hetero-metallic compounds derived from Cu(II) chelates of N 2 O 2 donor di-Schiff base ligands. [Display omitted] • Hetero-metallic complexes of Cu(II) bound N 2 O 2 donor Schiff bases with Zn(II)/Cd(II)/Hg(II). • Different synthetic approaches (mostly "complex as ligand") for the isolation of hetero-metallic complexes. • Effects of coordination motif of anionic coligands on structural diversities and nuclearities of complexes. • Few novel isomers in coordination chemistry have been described. A good number of heterometallic complexes based on various Cu(II) bound "metalloligands" of N 2 O 2 donor di-Schiff bases and some of their reduced counterpart along with group 12 metal ions have been synthesized and characterized by different research groups in the literature. This review focuses on an overview of the synthetic strategies, X-ray crystallographic structures and a few important properties of these complexes. These have been discussed in three major sub-classes: Cu(II)-Zn(II), Cu(II)-Cd(II) and Cu(II)-Hg(II) heterometallic complexes. Judicious combinations of carbonyls and di-amines in an easy and effective manner gives 14 selected di-Schiff base ligands (symmetrical and unsymmetrical) with particular shape, geometry and denticity that direct the synthesis of these metal complexes totally or preferentially towards di-, tri- or poly-nuclear entities. Moreover, owing to their ability to assemble three metal ions in close proximity, these resulting oxido-bridged flexible coordination clusters adapted to various other ligand functionalities with particular shape and sometimes unusual coordination modes with certain degree of control. Such unique structural aspect of this system is immensely important in inorganic synthesis. The inherent flexibility of the di-oxido bridged trinuclear coordination cluster led to produce isomeric linear and bent structures that usually depend upon various factors e.g. the nature of the Schiff base, anionic co-ligands, temperature, solvent etc. The structural aspects of resulting discrete and polymeric self-assemblies have enriched the coordination library that extended to develop numerous heterometallic systems with significant applications and new scopes [ABSTRACT FROM AUTHOR]

The recognition of nitroexplosives is a pivotal area of research, vital for homeland security and environmental safety. This critical review aims to succinctly outline the key characteristics of luminescent Zn(II) Schiff base complexes, highlighting their design, synthesis, and sensing abilities, with a specific emphasis on their role in nitroexplosives detection. [Display omitted] • Discussion on different luminescent chemosensors for the detection of nitroexplosives. • Brief discussion on the advantages of using zinc(II) Schiff base complexes as chemosensors. • Brief discussion on different synthetic strategies of the zinc(II) Schiff base complexes. • Highlights on their sensing mechanism. In this review, we briefly summarize the key aspects of the synthetic strategies for zinc(II) Schiff base complexes, focusing on their photophysical properties such as the origin of luminescence, intensity, lifetime, and quantum yield. Additionally, we discuss the advantages of using luminescent zinc(II) complex-based sensors, the factors underlying their effectiveness as chemosensors for explosive detection, their mechanisms of action, and future outlooks and concerns. Most of the zinc(II) Schiff base complexes reported to date function as turn-off luminescent chemosensors for nitroexplosives. Some zinc(II) complexes discussed in this review demonstrate very high selectivity and sensitivity, with limits of detection (LOD) in the ppb or nM range for picric acid. Additionally, certain zinc(II) complexes can detect picric acid in the solid state through a visible color change observable to the naked eye under ambient light. [ABSTRACT FROM AUTHOR]

Synthesis and catalytic studies of aryl carboxylate Zn (II) complexes is reported. Reaction of substituted (E)-N-phenyl-1-(pyridin-4-yl)methanimine with a methanolic solution of Zn(CH3COO)2 and substituted aryl carboxylate co-ligands gave heteroleptic Zn(II) complexes; [Zn(C6H5COO)2(L1)]2 (1), [Zn(C7H7COO)2(L1)]2 (2), [Zn (4-F-C6H4COO)2(L1)]2 (3), [Zn(C6H5COO)2(L2)]2 (4), [Zn(C7H7COO)2(L2)]2 (5), [Zn (4-F-C6H4COO)2(L2)]2 (6), [Zn(C6H5COO)2(L3)]2 (7), [Zn(C7H7COO)2(L3)]2 (8), [Zn (4-F-C6H4COO)2(L3)]2 (9). The molecular structures of complexes 1 and 4 are dinuclear with the zinc atom in complex 1 adopting a distorted trigonal bipyramidal geometry in a bi-metallacycle while complex 4 is square pyramidal where all four benzoate ligands bridge the zinc metals in a paddle wheel arrangement. All complexes successfully initiated mass/bulk ring-opening polymerization (ROP) of ϵ-caprolactone (ϵ-CL) and lactides (LAs) monomers with or without alcohol co-initiators at elevated temperatures. Complexes 1, 4 and 6 containing the unsubstituted benzoate co-ligands were the most active in their triad; with complex 4 being the most active (kapp) of 0.3450 h−1. The physicochemical properties of the polymerization products of l-lactide and rac-lactide in toluene revealed melting temperatures (Tm) between 116.58 °C and 188.03 °C, and decomposition temperatures between 278.78 °C and 331.32 °C suggestive of an isotactic PLA with a metal capped end.

The trinuclear [Zn3(PMT)2(Cl4)(N3)2] complex of the N-pincer ligand, 2,4-bis(3,5-dimethyl-1H-pyrazol-1-yl)-6-methoxy-1,3,5-triazine (PMT), was obtained by self-assembly of the polydentate ligand (PMT) with ZnCl2 in the presence of azide ion as an auxiliary bridging ligand. The X-ray structure analysis revealed a monoclinic crystal system and centrosymmetric space group C2/c. There are two crystallographically independent Zn(II) sites where the Zn1 and Zn2 are tetra- and penta-coordinated with ZnN2Cl2 and ZnN4Cl coordination environments, respectively. The distortion τ4 and τ5 parameters for the Zn1 and Zn2 sites are 0.93 and 0.52, respectively. Hence, the Zn(1)N2Cl2 has a distorted tetrahedral configuration, while the Zn(2)N4Cl coordination sphere is intermediate between the square pyramidal and trigonal bipyramidal configurations. In this complex, the PMT is a tridentate N-chelate, while the chloride and azide anions are terminal and μ(1,1) bridged ligands, respectively. The %H...H, N...H, Cl...H, and C...H are 40.8, 17.2, 16.0, and 10.1%, respectively, based on Hirshfeld analysis. The charges at the Zn1 (+0.996 e) and Zn2 (+1.067 e) sites are calculated to be less than the official charge of the isolated Zn(II) ion. The μ(1,1) bridged azide has two asymmetric N–N bonds with clear covalent characters. In contrast, the Zn–N and Zn–Cl bonds have predominant closed-shell characters. [ABSTRACT FROM AUTHOR]

Zinc(II)-niacinamide complexes from various Zn(II) salts were prepared and their antibacterial activities toward the E. coli and S. aureus are reported here. The effect of the M: L molar ratio (1:2, 1:4, 1:6) on the yield was studied and a possible molecular formula of the products was also proposed. Sulfate, nitrate, chloride, and acetate were used as the Zn(II) salts. The solid products were characterized by SEM, FTIR, powder XRD, melting point test, and qualitative anion identification test. Experimental data shows that solid products were only yielded from the chloride and sulfate salts. The larger the molar ratio used, the higher the crystal yield obtained. The colorless crystals obtained from the sulfate and the chloride reactions are predicted to be complexes of [Zn(L)x(SO4)] and [Zn(L)x]Cl2, respectively. Antibacterial test of both metal complexes toward E. coli and S. aureus shows that the complexes have better activity than that of the niacinamide. [ABSTRACT FROM AUTHOR]

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Several metal diimine complexes have been reported to possess anticancer properties. To evaluate the anticancer properties of tetrahedral zinc(II) diimine complexes, six complexes were synthesized with the general formula M(N^N)Cl2 {where M = Zn, Pt and N^N = 2,2’-biquinoline (1), 2,2’-dipyridylketone (2) and 4-((pyridine-2-ylmethylene)amino)phenol (3)}. In general, the intrinsic DNA-binding constants for the different compounds exhibited values within close proximity; the changes in the viscosity of the CT-DNA upon binding to the compounds suggest intercalation-binding mode. Molecular docking study predicted that complexes containing the highly planar ligand 2,2’-biquinoline are capable to establish π–π interactions with nucleobases of the DNA; the other four complexes engaged in donor–acceptor interactions with DNA nucleobases. The six complexes and two reference drugs (cisplatin and sunitinib) were tested against two cancer cell lines (COLO 205 and RCC-PR) and one normal cell line (LLC-MK2), highlighting the better performance of the zinc(II) complexes compared to their platinum(II) analogues. Moreover, zinc(II) complexes have higher selectivity index values than the reference drugs, with promising anticancer properties.

A series of Schiff base derivatives, namely N-(4-methoxyphenyl)-1-(1-methylbenzimidazol-2-yl)methanimine (L1), 4-methoxy-N-[(1-methylbenzimidazol-2-yl)methyl]aniline (L2), and 2-[(E)-(1-propylbenzimidazol-2-yl)iminomethyl]phenol (L3), were synthesized. These compounds feature different linker groups, including –CH=N–, –CH2–NH–, and –N=CH–, respectively. During the process of zinc(II) and cadmium(II) complexation in the presence of the closo-dodecaborate [B12H12]2– anion, it was observed that ligand L3 underwent degradation. Consequently, two compounds were isolated, [Zn(Bz-NH2)2(CH3COO)2] and (HBz-NH2)2[B12H12]∙2CH3CN, both containing 1-propyl-2-aminobenzimidazole (Bz-NH2), which is a degraded fragment of the ligand. Several new zinc(II) and cadmium(II) coordination compounds were synthesized and characterized using various physicochemical analysis methods, including elemental analysis, IR, and UV spectroscopy. Additionally, X-ray diffraction and Hirshfeld surface analysis were performed for compounds [Cd(L2)2(CH3CN)(H2O)][B12H12], [Zn(Bz-NH2)2(CH3COO)2], and (HBz-NH2)2[B12H12]∙2CH3CN, as well as for ligand L2.

A combination of 4-styrylpyridine (spy) and 1-adamantanecarboxylic acid (Hadc) was employed in the assembly reactions with Zn(II) and Cu(II) nitrates. The photoreactivity of the products was compared and discussed on the basis of the structure–function relationship. Zinc(II) complex 1 is a trinuclear species of type [Zn3(spy)2(adc)6] in which three zinc(II) atoms are linearly arranged, with two adjacent zinc(II) atoms linked by three bridging carboxylates. Two spy ligands occupy both terminal positions, yielding the overall structure of a six-bladed windmill. Copper(II) complex 2, [Cu(spy)2(adc)2][Cu2(spy)2(adc)4]·2DMF, is an inorganic cocrystal comprising a mononuclear complex with a trans square planar geometry and a dinuclear complex with a paddle-wheel structure. In the photoreaction experiments characterized by 1H NMR spectroscopy, the zinc(II) complex was found to be photoinert, while the copper(II) complex was photoreactive to form a cyclobutene ring via the [2+2] photodimerization between two spy ligands, resulting in the preparation of a one-dimensional chain as a coordination polymer. The separations of the C=C bond pair obtained from the crystal structures for both products also support their photoreactivity. For example, the spy ligands from two adjacent monocopper(II) complexes are aligned in a head-to-tail manner with the separation of 3.899 Å between the C=C bond pair, satisfying the so-called Schmidt criteria (

The present study reports on a 2D lamellar coordination polymer (CP) of {[Zn(µ3-pmdc)(H2O)]·H2O}n formula (pmdc = pyrimidine-4,6-dicarboxylate). This CP is synthesized under an appropriate acid-base reaction between the gently mortared reagents in the solid state through a solvent-free procedure that avoids the presence of concomitant byproducts. The X-ray crystal structure reveals the occurrence of Zn2 entities connected through carboxylate groups of pmdc, which behave as triconnected nodes, giving rise to six-membered ring-based layers that are piled up through hydrogen bonding interactions. In addition to a routine physico-chemical characterization, the thermal evolution of the compound has been studied by combining thermogravimetric and thermodiffractometric data. The photoluminescence properties are characterized in the solid state and the processes governing the spectra are described using time-dependent density-functional theory (TD-DFT) with two different approaches employing different program packages. The emissive capacity of the material is further analyzed according to the dehydration and decreasing temperature of the polycrystalline sample.

A fluorescence peptide-based sensor (Dansyl-His-Thr-Glu-His-Trp-NH2, D-P5) was synthesized by Fmoc solid phase peptide synthesis, using dansyl group as the fluorophore. The sensor exhibited different fluorescence responses and sensitive detections for copper(II), mercury(II) and zinc(II) ions as a multifunctional sensor. The detailed investigation suggested that the limits of detection were 37.6 nmol⋅L−1, 37.8 nmol⋅L−1 and 59.4 nmol⋅L−1 for copper(II), mercury(II) and zinc(II) ions, respectively, and the highly sensitive sensor was not influenced by other species. The sensor exhibited a strong binding ability to copper(II), mercury(II) and zinc(II) ions with the binding constants of 3.23 × 105 L⋅mol−1, 6.37 × 105 L⋅mol−1 and 6.0 × 104 L⋅mol−1, respectively. The binding stoichiometries of the sensor to copper(II), mercury(II) and zinc(II) ions measured by Job's plot were all 1:1. Furthermore, The sensor has been successfully used for the detections of copper(II), mercury(II) and zinc(II) in actual water samples. [ABSTRACT FROM AUTHOR]

The Zn2+/Ag+-pypo and pysu (pypo = 2-pyridylphosphonate, pysu = 2-pyridylsulfonate) complexes speciation in aqueous solution at I = 0.1 M (KNO3) and 25 °C is described in detail under our experimental synthetic conditions. Protonation and stability constants were determined, and distribution diagrams show protonated and deprotonated complexes formation in the case of Zn2+/Ag+ pypo/pysu binary system, respectively. Moreover, the new complex, {[Zn(H2pypo)2(H2O)2]}n(ClO4)2n·2nH2O, was isolated and its spectral and structural properties were determined. An unusual pypo bidentate coordination mode is described and compared with published ones. [ABSTRACT FROM AUTHOR]