Zinc Coordination Complexes Research Articles

Harnessing Novel Zinc(II) Coordination Complex for Green Synthesis of ZnO Nanoparticles Boasting Remarkable Photocatalytic Degradation and Targeted Detection of Cr(VI) and Hg(II) Ions

Harnessing Novel Zinc(II) Coordination Complex for Green Synthesis of ZnO Nanoparticles Boasting Remarkable Photocatalytic Degradation and Targeted Detection of Cr(VI) and Hg(II) Ions

Structure of Metiram, a Crystalline Zinc Coordination Complex with Amorphous Side Phase

Structure of Metiram, a Crystalline Zinc Coordination Complex with Amorphous Side Phase

An all-rounder aminoguanidine based ligand, its unusual anionic zinc(ii) and cadmium(ii) coordination complexes and their biological implications

The versatility of the ligand by protonating and deprotonating in the same medium yields unparallel complexes, one of which is more potent against E. coli than the standard ciprofloxacin, and opens-up new possibilities in coordination chemistry.

Polymorph driven diversification of photosalient responses in a zinc(II) coordination complex.

A novel crystallographic form of a Zn(II) coordination complex [Zn(4-ohbz)2(4-nvp)2] (1-Form-III) (H4-ohbz = 4-hydroxybenzoic acid and 4-nvp = (E)-4-(1-naphthylvinyl)pyridine), undergoes a solid-state photochemical [2+2] cycloaddition reaction accompanied by a moderate photosalient effect, whereby single-crystals show cracking and splitting. This UV-induced cycloaddition accompanies a single-crystal to single-crystal transformation, allowing for continuous monitoring of the unit cell parameters. The new polymorph represents an intermediate form of the two previously reported crystallographic forms of [Zn(4-ohbz)2(4-nvp)2], and provides novel insight into moderating the magnitude of photosalient responses across polymorphic materials.

Photophysical, thermal, and DFT studies on a tetraaryl-azadipyrromethene ligand and its zinc(II) complex.

An azadipyrromethene ligand (H1) and homoleptic zinc(II) (H1-Zn) complex were synthesized. The resulting structures were elucidated by NMR, FTIR, and HRMS techniques. The photophysical properties and effects of complexing the zinc(II) atom to azadipyrromethene ligands in solution were studied by means of UV-Vis absorption and fluorescence spectroscopy. Experimental findings were elucidated using density functional theory computations and interfragment charge transfer (IFCT) and electron-hole analyses. The fluorescence features were found to be negligible. The ligand molecule decayed at a rate of 3% while the complex decayed at 2% upon photoirradiation based on photostability experiments. The singlet oxygen quantum yields of the ligand and complex were calculated as 0.127 and 0.233, respectively, signifying low photodynamic activity. The charge transfer transitions were determined between reciprocal ligands responsible for the red shift of the main absorption band by IFCT and electron-hole analysis. Compounds in an inert N2 atmosphere demonstrated high thermal stability. Although the thermogravimetric analysis (TGA) and derivative thermogravimetry curves of the complexes were similar, zinc(II) coordination and homoleptic complex formation reduced the degradation temperatures. These findings suggest that azadipyrromethene and the Zn(II) class of chromophores have beneficial features for use in the development of novel photo- and thermostable materials that combine charge transfer with low energy in the visible and near infrared regions.

Two new zinc(ii) coordination complexes constructed by phenanthroline derivate: Synthesis and structure

Abstract Two new Zn(ii) coordination complexes [Zn(L)(dna)(H2O)] (1) and [Zn(L)(glu)]2·H2O (2) (L = 2-(4-fluorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline, H2dna = 3,5-dinitrosalicylic acid, H2glu = glutaric acid) have been hydrothermally synthesized and characterized by single crystal X-ray diffraction, elemental analysis, fluorescence spectrum, and infrared spectroscopy. For complex 1, the dna2− anion adopts μ 1 -η 1 :η 1 chelating bidentate mode to coordinate with one Zn(ii) atom and π–π stacking interactions are formed between the L ligands. For complex 2, glu2− anions connect Zn(ii) atoms to form a wavy two-dimensional layer, and the L ligands are attached on two sides of the two-dimensional layer.

Comparative Analysis of Physical and Chemical Properties of Differently Obtained Zn-Methionine Chelate with Proved Antibiofilm Properties (Part II).

The previously demonstrated activity of aqueous solutions of methionine and zinc salts against biofilms of uropathogenic bacteria prompted us to investigate the structure and properties of zinc methionine complex obtained from such solutions. The paper presents the analysis results of zinc coordination complexes with methionine obtained by synthesis (0.034 mol of L-methionine, 0.034 mol of NaOH, 40 mL of H2O, 0.017 mol ZnSO4, 60 °C) and simple crystallization from water solution (25 mL of a solution containing 134 mmol/L L-methionine, 67 mmol/L ZnSO4, pH = 5.74, I = 0.37 mmol/L, crystallization at room temperature during more than two weeks). IR spectral analysis and X-ray diffraction showed the structural similarity of the substances to each other, in agreement with the data described in the literature. DSC confirmed the formation of a thermally stable (in the range from -30 °C to 180 °C) chelate compound in both cases and indicated the possible retention of the polymorphic two-dimensional structure inherent in L-methionine with the temperature of phase transition 320 K. The crystallized complex had better solubility in water (100 to 1000 mL per 1.0 g) contra the synthesized analog, which was practically insoluble (more than 10 000 mL per 1.0 g). The results of the solubility assessment, supplemented by the results of the dispersion analysis of solutions by the dynamic light scattering method indicated the formation of zinc-containing nanoparticles (80 nm) in a saturated water solution of a crystallized substance, suggesting the crystallized substance may have higher bioavailability. We predicted a possibility of the equivalent existence of optically active cis and trans isomers in methionine-zinc solutions by the close values of formation enthalpy (-655 kJ/mol and -657 kJ/mol for cis and trans forms, respectively) and also illustrated by the polarimetry measurement results (∆α = 0.4°, pH = 5.74, C(Met) = 134 mmol/L; the concentration of metal ion gradually increased from 0 to 134 mmol/L). The obtained results allowed us to conclude that the compound isolated from the solution is a zinc-methionine chelate with the presence of sulfate groups and underline the role of the synthesis route for the biopharmaceutical characteristics of the resulting substance. We provided some quality indicators that it may be possible to include in the pharmacopeia monographs.

Synthesis, structure characterization, spectral properties, DFT calculations, hirshfeld surface analysis, thermal stability and bioactivity of a new sulfamethoxazole zinc(II) complex

This study reports the synthesis of a new sulfamethoxazole zinc(II) coordination complex: bis(5-methyl-3-isoxazol-2-yl sulfanilamido)-diaqua-zinc(II), C20H24N6O8S2Zn, (I). Synthesized compound has been fully characterized by single-crystal and powder X-ray diffraction, FT-IR, UV–visible absorption and NMR (1H and 13C) spectroscopy techniques. In Zn(II) coordination sphere, sulfamethoxazole behaved as monodentate ligand and coordinated via nitrogen of sulfonamide group. Complex (I) was recovered in its crystalline form and was analyzed by single-crystal X-ray diffraction technique which held orthorhombic crystal system with space group (Pnma). The molecules of (I) are linked into chains through intermolecular N–H···O, O–H···O and C–H···π non covalent interactions. The intermolecular contacts were examined using Hirshfeld Surface investigation. Furthermore, computational analysis were performed through Density Functional Theory (DFT) utilizing the mPW1PW91 basis set at the TZVP level of theory and the theoretical results were correlated with experimental data. The antimicrobial and antifungal activities of the free ligand and its synthesized Zn(II) coordination complex were evaluated using the well-diffusion method in DMSO. The microbial strains investigated include one Gram-positive, five Gram-negative and three funguses bacterial strains using the standard antibiotics “Cotrimoxazole” as positive control.

A bowl-shaped phenoxido-bridged binuclear zinc complex: Experimental and theoretical studies

A new dinuclear zinc coordination complex with di(μ-alkoxido) bridge obtained from [[H2L = N,N-(salicyaldene)-1,3-diaminopropan-2-ol] was investigated by IR, 1H- &13C NMR spectroscopy. Single crystal X-ray analysis reveals that the Zn1 atom in the title complex is five coordinated and bound to two alkoxide atoms, two nitrogen atoms, and a chloride ion at apical position in distorted square pyramid geometry, while the second central cation, Zn2, is four coordinated and its O2Cl2 coordination environment is distorted tetrahedral. The single-crystal X-ray crystallographic measurements and DFT calculations reveal that the complex has a bowl-like structure. Hirschfeld surface analysis, energy frameworks QTAIM, NBO, and EDA analyses show clearly that the structure contains a variety of classical and non-classical interactions that help to extend the crystal net dimension. TGA is used to investigate the stability of the structure of the title complex.

Synthesis and Photophysical Properties of Multi‐Functional Bisimidazolyl Phenol Zinc (II) Complex: Application in OLED, Anti‐Counterfeiting and Latent Finger Print Detection

Abstract+An aggregation‐induced emission‐based, luminescent Zinc (II) coordination complex of bisimidazolyl phenol (Zn‐BDI) is prepared. The thermal stability of the complex Zn‐BDI is attributed to the twisted conformation, and the rigid molecular structure of the ligand BDI resulted from the incorporation of the Zn‐metal atom. The maximum emission of the Zn‐BDI appears to be at 475 nm and emits strong cyan fluorescence. The light emission performance of the prepared zinc complex in organic light‐emitting diodes (OLEDs) indicates fairly good electroluminescence properties (max. brightness 13500 cd/m2, max. EQE=3.8 %). Moreover, these Zn‐BDI can emit strong cyan‐blue luminescence with a high quantum efficiency (0.83), and hence, latent fingerprint (LFPs) investigation exhibited permanent, immutable, and unique pores that are distributed on the ridges. Collectively, the prepared Zn complex offers a new avenue for the OLED and LFP applications.

Coordination complexes of zinc and manganese based on pyridine-2,5-dicarboxylic acid N-oxide: DFT studies and antiproliferative activities consideration.

We report here the design, synthesis, and antiproliferative activity of three coordination complexes [Mn2(pydco)2(bpy)2(H2O)2]·2H2O (1), [Zn(bpy)(Hpydco)2] (2), and [Zn(bpy)Cl(Hpydco)]·2H2O (3) (H2pydco = pyridine-2,5-dicarboxylic acid N-oxide, bpy = 2,2′-bipyridine). Molecular structures of these complexes have been characterized by elemental analysis, Fourier transform infrared spectroscopy, thermogravimetric analysis, and powder and single-crystal X-ray diffraction. According to the structural analysis, 1–3 are discrete complexes containing N- and O-donor ligands (bpy and pydco2−) in which pydco2− can be coordinated to the metal centres via the N-oxide oxygen and one carboxylate oxygen to generate a six-membered chelate ring. Also, these structures benefit from extensive intermolecular interactions such as hydrogen bonds and π-interactions which are the major forces to make them more stable in the solid state. The energetic features of the π-stacking interactions observed in compounds 1–3 have been computed and compared to the H-bonds. The interactions in the solid state have been also studied using the independent gradient model approach (IGM plot). The IGM-δg approach uses a new descriptor (δg) that locally represents the difference between a virtual upper limit of the electron density gradient and the true electron density gradient. This newly developed IGM methodology automatically extracts the signature of interactions between two given fragments. Finally, the antiproliferative properties of these complexes were tested on several cancer cell lines by MTT assay and flow cytometry. Also, to compare the antiproliferative activities of these complexes with common chemotherapy drugs, the antiproliferative property of cisplatin was evaluated as a reference and positive control.

Assembly, photocatalytic and fluorescence properties of three new coordination complexes of zinc(II) and nickel(II) with two kinds of flexible bis(pyridyl)-bis(amide) ligands

Abstract Three new coordination complexes [Zn(btec)0.5(L1)0.5(H2O)] n (1), [Ni(H2btec)(L1)(H2O)2] n (2), and {[Ni(btec)0.5(L2)(H2O)3]·2H2O} n (3) [H4btec = 1,2,4,5-benzenetetracarboxylic acid), L1 = N,N′-bis(3-pyridyl)adipamide, L2 = N,N′-bis(3-pyridyl)octanediamide] have been obtained under hydrothermal conditions. Single-crystal X-ray diffraction analysis has revealed that complex 1 has a layer structure based on [Zn(btec)0.5] n ribbons and the μ 2-bridging ligands L 1 . Complex 2 possesses a layered framework constructed by [Ni(H2btec)] n linear chains and [Ni(L1)] n wave-like chains. Complex 3 forms layers based on [Ni(L2)] n helical chains and μ 2-bridging L2 ligands, representing an interesting 4-fold interpenetrating 2D braided framework. The three different 2D frameworks exhibit 3,4-connected {4.62}2{42.62.82} topology for 1, 4-connected {44.62} topology for 2 and 3-connected {63} topology for 3. Their adjacent layers are further linked by hydrogen bonding interactions to generate 3D supramolecular structures. The differences in the nature of both the metal ions and the organic ligands lead to various coordination modes in the final structures. The photocatalytic activities and the fluorescence properties of complexes 1–3 were investigated.

Zinc Complexes with Nitrogen Donor Ligands as Anticancer Agents.

The search for anticancer metal-based drugs alternative to platinum derivatives could not exclude zinc derivatives due to the importance of this metal for the correct functioning of the human body. Zinc, the second most abundant trace element in the human body, is one of the most important micro-elements essential for human physiology. Its ubiquity in thousands of proteins and enzymes is related to its chemical features, in particular its lack of redox activity and its ability to support different coordination geometries and to promote fast ligands exchange. Analogously to other trace elements, the impairment of its homeostasis can lead to various diseases and in some cases can be also related to cancer development. However, in addition to its physiological role, zinc can have beneficial therapeutic and preventive effects on infectious diseases and, compared to other metal-based drugs, Zn(II) complexes generally exert lower toxicity and offer few side effects. Zinc derivatives have been proposed as antitumor agents and, among the great number of zinc coordination complexes which have been described so far, this review focuses on the design, synthesis and biological studies of zinc complexes comprising N-donor ligands and that have been reported within the last five years.

Solvothermal preparation of luminescent zinc(II) and cadmium(II) coordination complexes based on the new bi-functional building block and photo-luminescent sensing for Cu2+, Al3+ and L-lysine

In industry, over usage of Cu2+ and Al3+ will lead to toxic wastewater, which further to give serious pollution for the environment. On the other hand, L-lysine can enhance serotonin release in the amygdala, with subsequent changes in psychobehavioral responses to stress. Therefore it is the urgent problem to design a method for detecting the amount of Cu2+, Al3+, and L-lysine. In this work, through the solvothermal synthesis method, two new coordination complexes based on the new bifunctional building block 4′-(1H-1,2,4-triazole-1-yl)- [1,1′-biphenyl]-4-carboxylic acid (HL) have been synthesized, namely, [Zn(L)2·4H2O] (complex 1) and [Cd(L)2·4H2O] (complex 2). X-ray single-crystal diffractometer was used to analyze its structure, powder X-ray diffraction (PXRD) patterns confirmed that 1 and 2 powder’s purity and 1 can keep stable during the detection process of Cu2+, Al3+, and L-lysine, respectively. Elemental analysis, thermogravimetric analysis, infrared analysis, ultraviolet analysis and fluorescent spectrum have been used to characterize these complexes. The photo-luminescent test showed that 1 can accurately recognize Al3+ and Cu2+ among various cations. On the other hand, 1 can distinguish L-lysine among amino acid molecules. Therefore, 1 can be utilized as a multifunctional fluorescent probe for Al3+(Ksv = 1.5570 × 104 [M]−1), Cu2+(Ksv = 1.4948 × 104 [M]−1) and L-lysine (Ksv = 4.9118 × 104 [M]−1) with low detection limits (17.5 μM, 18.2 μM, 5.6 μM) respectively.

Iron(III), cobalt(II) and zinc(II) coordination compounds with a carboximidamide ligand: Synthesis, structures and properties

Coordination complexes of iron(III), cobalt(II) and zinc(II) with the ligand N′-{[1-(pyridin-2-yl)ethylidene]amino}pyridine-2-carboximidamide (pmhpa) have been synthesised and were structurally characterized by elemental analysis, mass spectrometry, X-ray diffraction and infrared spectroscopy. The mononuclear iron(III) complex, [Fe(pmhap)2][FeCl4], (1), adopts the orthorhombic non-centric space group P212121. The iron is present in an octahedral environment in the ion [Fe(pmhap)2]+. The crystallographically-determined formula of the cobalt(II) complex (2) is [Co2(pmhap)2Cl3]2[CoCl4].4MeOH. The compound crystallizes in the non-centric space group P4̄21c with a single cobalt ion in the asymmetric unit. The complex is dinuclear, with two cobalt ions bridged by chloride and the two nitrogen atoms of N=N of the pmhap ligand. The zinc(II) complex; [Zn2(pmhpa)3](NO3)4.2.75MeOH (3) crystallizes in the cubic space group Pa3̄ with disordered methanol molecules present. This is dinuclear with the two zinc atoms being bridged by three N=N links from the ligand to form a threefold symmetric rotor. Infrared spectroscopy confirms that coordination occurs through the azide bridge. Measurements of magnetic susceptibility for the iron(III) and cobalt(II) complexes show that they are paramagnetic between 5 and 300 K. Mössbauer spectroscopic data supports the structure of the iron(III) complex being composed of an octahedral and a tetrahedral iron atom.

Syntheses, structures and properties of two zinc(II) coordination complexes based on two bis(pyridyl)-bis(amide) ligands and 1,2-phenylenediacetic acid

Two new zinc(II) coordination complexes [Zn(pda)(3-bpcd)0.5] (1) and [Zn(pda)(3-bpoa)]·H2O (2) have been synthesized by self-assembly of 1,2-phenylenediacetic acid (H2pda), semi-rigid/or flexible bis(pyridyl)-bis(amide) ligands [3-bpcd = N,N′-bis(pyridin-3-yl)cyclohexane-1,4-dicarboxamide, 3-bpoa = N,N'-bis(3-pyridyl)octandiamide] and zinc nitrate. Complex 1 is a 2 D layered framework derived from the 1 D [Zn(pda)]2n ribbon-like chain and the bidentate 3-bpcd, which is a (3,4)-connected (42·63·8)(42·6) topology, then the adjacent layers are linked by hydrogen bonds to build a 3 D supramolecular network. Complex 2 displays a 3 D framework based on the 1 D [Zn(pda)]2n ribbon-like chains and the 1 D [Zn(3-bpoa)]n chains, which represents a (3,5)-connected (42.65.83)(42.6) topology. Two bis(pyridyl)-bis(amide) ligands with different flexibilities play an important role in constructing final topological structures for title complexes. Moreover, the fluorescent properties of two zinc(II) complexes and their fluorescent sensing properties toward small solvent molecules have been studied. Additionally, the photocatalytic properties of complexes 1 − 2 toward the degradation of dyes have been investigated.

Synthesis, structure and theoretical simulation of a zinc(II) coordination complex with 2,3-pyridinedicarboxylate

Hydrolytic opening reaction of 2,3-pyridine dicarboxylic anhydride with the zinc dichloride led to form the chelate complex of mono deprotonated 2,3-pyridine dicarboxylic acid, [Zn(2,3-pdcH)2(H2O)2], (2,3-pdcH = 2,3-pyridinedicarboxylic acid). The coordinated compound crystallizes in the monoclinic space group P21/n. The crystal structure of the title compound exhibits a homoleptic complex with distorted octahedral geometry and ligand coordinated via pyridine nitrogen and oxygen atoms from one deprotonated dicarboxylic acid. Intermolecular interactions were analysed by Hirshfeld surfaces. After formation of the metal complex, the crystal packing is stabilized by O–H⋯O and C–H⋯O hydrogen bonds. There are moreover hydrophobic interactions, which consist in stacking between the pyridine cycle and the carboxylic/carboxylate groups. NBO and QTAIM analyses have been performed to evaluate the charge delocalization interactions that occur between the Zn(II) central ion and the surrounding ligand donor atoms. The HOMO and LUMO energies and Molecular Electrostatic Potential surface were derived from DFT theoretical calculations.

Tetrahedral Zinc(II) Complexes with Chiral Diamine Ligands: Synthesis, Characterization, and Photoluminescence

Emission spectra of tetrahedral zinc(II) coordination complexes with chiral ligands. Figure S1 1H NMR spectrum of 1 in DMSO‑d6 (500 MHz). Figure S2. 13C NMR spectrum of 1 in DMSO‑d6 (125 MHz). Figure S3. IR spectrum of 1 in KBr pellet. Figure S4. 1H NMR spectrum of 2 in DMSO‑d6 (500 MHz). Figure S5. 13C NMR spectrum of 2 in DMSO‑d6 (125 MHz). Figure S6. IR spectrum of 2 in KBr pellet. Figure S7. UV–vis spectra of 1 and 2 in the solid state. Figure S8. UV–vis spectra of 1 and 2 in CHCl3 solution. Figure S9. Excitation and emission spectra of 1 and 2 in the solid state. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

A Zinc Coordination Complex Mimicking Carbonic Anhydrase for CO2 Hydrolysis and Sequestration.

Carbonic anhydrase (CA) mimicking is an effective and environmentally friendly strategy for carbon dioxide sequestration. Herein, we developed a nonanuclear CA-mimetic zinc coordination complex (1) which possesses a coordination environment similar to that of CA's catalytically active zinc sites. Complex 1 exhibited excellent reusability, solvent and thermal stability, and gram-scale synthesis, which are essential for practical applications. It was found that complex 1 exhibited outstanding catalytic performance that is much better in comparison to that of the popular CA-mimetic compound Zn-cyclen and comparable to that of the reported metal-organic frameworks (e.g., CFA-1). Moreover, we found that its catalytic activity can be significantly improved via OAc-/OH- exchange and particle size reduction treatment. This study provides important guidance for the design of highly efficient CA-mimetic materials.

Single crystals and nanoparticles of Zn(II) supramolecular compounds via sonochemical method: Synthesis, characterization and structural studies

The zinc coordination complexes [ZnBr2(DTDS)]⋯H2O (1) [DTDS = 1,2-di(1H-1,2,4-triazol-3-yl) disulfane] and [ZnI(2,2′-bipy)(chb)] (2) (2,2′-bipy = 2,2′-bipyridine; Hchb = 5-chloro-2-hydroxybenzophenone) were prepared as single crystals by conventional solution chemistry and as crystalline nanoparticles under ultrasonic irradiation. The structures of 1 and 2 were determined by single crystal X-ray diffraction. PXRD confirmed that the nanoparticles have the same structure. They were additionally characterized by scanning electron microscopy. The structures were analyzed by Hirshfeld surface analyses to provide more information on the supramolecular interactions and crystal packing.