Coordinated Water Research Articles

Synthesis, characterization, theoretical calculation, DNA binding, molecular docking, anticovid-19 and anticancer chelation studies of some transition metal complexes

The globe has recently been consumed by frightening viral pneumonia (COVID-19). The new strain of the virus, called SARS-CoV-2, belongs to the family of coronaviruses, so research is aimed at screening ligands and drugs for multimodal structure-based structure-design and then docking to the main viral protease to examine the active binding sites. The complexes of Cu(II), Ni(II) Zn(II) and Mn(II) with 3-Cyano-6-(p-chlorophenyl) azo-7-hydroxy coumarin (HL) were synthesized and characterized by elemental analyses, IR, UV-Visible, magnetic measurements and thermal analyses. The measurements of molar conductance showed that all the complexes are non-electrolyte. The IR spectra showed that the ligand (HL) acts as a monobasic bidentate ligand by coordinating via the nitrogen atom (-N = N-) and deprotonated -OH group. Analytical data showed that all complexes exhibited a ratio of 1:1 (metal-ligand). The thermal data indicate that some complexes have outside water molecule and some have within the domain of coordination water molecule, and the complexes display identical fragments of thermogravimetric decomposition that are compatible with the proposed structures. Mass spectra were also used to make the large fragments of the ligand and Ni (II) complex, with the main peaks corresponding to molecular weight using quantum chemical equations.

Zinc(II) and copper(II) complexes constructed from new bis(1H-1,2,3-triazole-4-carboxylate)-based ligands

Using triazolyl based ligands bearing carboxylate groups and cationic species [Cu(NN)(acac)(H2O)]+ and [Zn(NN)2(acac)]+ seven new coordination complexes have been synthesized: [Cu2(bipy)2(7a-2H)(H2O)2](7a-2H)⋅2H2O⋅4DMF 8, [Cu(phen)(7a-2H)]⋅7H2O 9, [Zn(bipy)(7a-2H)]⋅6H2O⋅DMF 10, [Zn(phen)(7a-2H)]⋅4H2O⋅2DMF 11, [Cu(phen)(7b-2H)(H2O)]⋅3H2O 12, [Zn(bipy)2(7b-2H)2(H2O)2]⋅4H2O 13 and [Zn(phen)(7b-2H)(H2O)2]⋅2H2O 14, 7a = 1,1′-(sulfonylbis(4,1-phenylene))bis(1H-1,2,3-triazole-4-carboxylic acid), 7b = 1,1′-(1,4-phenylene)bis(1H-1,2,3-triazole-4-carboxylic acid), bipy = 2,2′-bipyridine, phen = 1,10-phenanthroline, acac− = acetylacetonate anion. Compound 8 is a dinuclear complex, where 7a-2H dianions function as bridging and uncoordinated ligand. Compounds 9-11 are 1-D coordination polymers with the angular spacer 7a-2H connecting the metal nodes in zig-zag chain motives. The mono- (12, 14) and dinuclear (13) units are generated by employing 7b as ligand. The supramolecular solid-state architecture is sustained by the presence of π-π stacking interactions (involving the pyridyl and phenyl group of the bis(1H-1,2,3-triazole-4-carboxylate) anions and co-ligand molecules) and hydrogen bonds (established between the aqua ligands, lattice water molecules and carboxylate groups).

Ligand Induced Double-Chair Conformation Ln12 Nanoclusters Showing Multifunctional Magnetic and Proton Conductive Properties.

Many methods have been utilized to adjust the size of superatomic metal nanoclusters, while tuning the geometric conformations of specific nanoclusters is rare. Here, we demonstrate that conformation variation can be realized by slightly modifying the ligand under maintaining the nuclei number of metal atoms. A series of novel "double-chair" conformation Ln12 (Ln = Sm (1), Eu (2), Gd (3), Tb (4), and Dy (5)) clusters were generated by replacing 3-formylsalicylic acid with 2,3-dihydroxybenzoic acid in the Ln12 nanocluster. Intriguingly, Dy12 displays slow magnetic relaxation at low temperatures, while Gd12 shows a large magnetocaloric effect (MCE) of 35.63 J kg-1 K-1 at 2 K for ΔH = 7 T. Additionally, the introduction of numerous coordination water molecules in these clusters enables Dy12 and Gd12 with high proton conductivity, namely, 2.13 × 10-4 and 3.62 × 10-4 S cm-1 under 358 K and 95% RH humidity conditions.

Single‐Crystal‐to‐Single‐Crystal (SCSC) Transformation of a Binuclear Cadmium (II) Complex to a Discrete Mononuclear Cadmium (II) Complex

AbstractA new binuclear complex {[Cd(phen)2(H2O)] ⋅ (TMA)2−}2 has been synthesized through the reaction of o‐phenanthroline (phen), 3‐thiophenemalonic acid (H2TMA), and cadmium acetate in a 1 : 2 (v/v) EtOH‐H2O mixture at room temperature. This complex can undergo single‐crystal‐to‐single‐crystal (SCSC) transformation to a new mononuclear complex [Cd(phen)3] ⋅ 2(HTMA)− ⋅ H2TMA} by a simple in‐situ solvent evaporation method at room temperature without changing the reaction system. In the whole SCSC process, with the solvent water molecules decreasing and the concentration of ligands increasing, the phen ligands replace the coordination water and coordinate with cadmium ions, finally resulting in the crystal structure transformation in the solid state.

Alkali-Induced In Situ Formation of Amorphous NixFe1-x(OH)2 from a Linear [M3(COO)6]-Based MOF Template for Overall Electrochemical Water Splitting.

Amorphous and bifunctional electrocatalysts based on 3d transition metals tend to exhibit better performance than their crystalline counterparts and are a promising choice for efficient overall water splitting yet far from being well explored. A 3,6-net metal-organic framework (MOF) of [Ni3(bpt)2(DMF)2(H2O)2]·1.5DMF (Ni-MOF), based on linear [Ni3(COO)6] as a node and [1,1'-biphenyl]-3,4',5-tricarboxylic acid (H3bpt) as a linker, was conveniently prepared via a hydrothermal reaction. Benefitting from the wide compatibility of the octahedral coordination geometry in Ni-MOF for different 3d metal ions, the molecular level and controllable metal doping facilitates the production of the desired Ni/Fe bimetallic MOF. A high-concentration alkali solution of 1 M KOH induced the in situ transformation of the MOF as a precursor to new amorphous electrocatalysts of [Ni(OH)2(H2O)0.6]·H2O [a-Ni(OH)2] and its metal-doped derivatives of a-Ni0.77Fe0.23(OH)2 and a-Ni0.65Fe0.35(OH)2. In particular, the costly organic ligand H3bpt was fully dissolved in the alkaline solution and can be recovered for cyclic utilization by subsequent acidification. The obtained amorphous hydroxide was deduced to be loose and defective layers containing both coordinated and lattice water based on combined characterizations of TG, IR, Raman, XPS, and sorption analysis. As opposed to the crystalline counterpart of Ni(OH)2 with stacked packing layers and an absent lattice water, the abundant catalytic active sites of the amorphous electrocatalyst endow good performance in both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). The bifunctional a-Ni0.65Fe0.35(OH)2 coated on nickel foam realizes small overpotentials of 247 and 99 mV for OER and HER, respectively, under a current density of 10 mA cm-2, which can work with a cell voltage of merely 1.60 V for overall water splitting. This study provides an efficient strategy for widely screening and preparing new functional amorphous materials for electrocatalytic application.

Achieving transmissive-to-black chromism via engineered dual electro-thermoresponsive single-molecule for full modulation of solar transmittance

Pursuit of complete and null transmissive optical material in smart windows for full control of the intensity and spectrum of incoming solar light has led to the advancement of transmissive-to-black chromism. While most reported transmissive-to-black devices are electrically stimulated, we report here an alternative approach based on dual stimulation of a new dual responsive molecule. By integrating asymmetric viologen onto a newly engineered poly(2-isopropyl-2-oxazoline)-based molecule, one can achieve transmissive-to-black chromism. The synergistic effect of its thermochromic and electrochromic response when stimulated simultaneously shows full absorption of the entire visible solar spectrum resulting to a truly black state that is ideal for building facades requiring absolute privacy. Autonomous chromic switchability function is also possible by independently stimulating the material either electrically or thermally where it displays unique colored state of vibrant magenta and a hazy state, respectively. Tunability of the material’s overall performance in terms of optical contrast, switching kinetics, coloration efficiency and cyclic stability based on the lattice water concentration was elucidated in this work. Furthermore, the fabricated device displays self-bleaching property and has a short-term “memory” effect that may broaden its potential for other applications.

Syntheses, spectroscopic, structural characterization of Co(III) and Co(II) carboxylates and electron transfer reactions with ferrocene derivatives

Herein we report five cobalt compounds; three compounds containing 5-nitroisophthalate viz. Bis{bis(2,2′-bipyridine-ĸ2-N,N')(carbonato-ĸ2-O,O')cobalt(III)}5-nitroisophthalate undeca-hydrate, [Co(bpy)2(CO3)]2(5-nip)·11H2O 1 synthesized by conventional steam bath reaction, while [Co(H2O)3(bpy)(5-nip)]·H2O 2 and polymeric [Co(5-nip)(bpy)(H2O)] 3 prepared under autoclave conditions. The two compounds of 4-nitrobenzoic acid viz. Bis(2,2′-bipyridine-ĸ2-N,N')(carbonato-ĸ2-O,O')cobalt(III)} 4-nitrobenzoate pentahydrate, [Co(bpy)2(CO3)](4-nba)·5H2O 4 and [Co2(4-nba)2(bpy)2(H2O)4](4-nba)25 were also obtained by steam bath and autoclave reactions. These compounds were characterized by single crystal X-ray diffractometry, elemental, spectroscopic, magnetic and thermal methods. Compounds 1 and 4 were studied by XPS, NMR, CV and VSM, revealing +3 oxidation state of Co. 1 showed eleven lattice waters while five waters were observed in 4 due to the change in carboxylate ligand. A large number of O-H···O and C-H···O interactions leading to extended networks were observed in their crystal structures. The thermal behavior of 1–5 was investigated using TG-DTA techniques. Both carbonato Co(III) compounds 1 and 4 were investigated for their oxidizing properties with ferrocene derivatives and the results of these electron transfer reactions are reported.

A novel magnetic CuFeAl-LDO catalyst for efficient degradation of tetrabromobisphenol a in water

• CuFeAl-LDO catalyst showed higher catalytic activity and better stability. • The co-existence of metal species enhanced the synergistic degradation property. • SO 4 •– , •OH and 1 O 2 were the main active species in CuFeAl-LDO/PMS system. • Response surface optimization could predict degradation performance effectively. • The degradation mechanism and toxicity of intermediates was investigated. Layered double hydroxide (LDHs) precursors were successfully prepared by co-precipitation method, and then the magnetic Cu 1 Fe 0.5 Al 0.5 -LDO catalyst was constructed and characterized after high-temperature calcination. In the Cu 1 Fe 0.5 Al 0.5 -LDO catalyst activated peroxymonosulfate (PMS) to degrade tetrabromobisphenol A (TBBPA) system, the effects of different reaction parameters, including catalyst dosage, PMS concentration, initial pH, common anion and natural water organic matter on the degradation of TBBPA were investigated. The results showed that the degradation rate of TBBPA (15 mg/L) by 0.1 g/L Cu 1 Fe 0.5 Al 0.5 -LDO catalyst and 0.5 mM PMS reached 99.91% within 60 min under the conditions of weak alkaline (pH = 8.5), and the reaction conditions were further optimized by response surface methodology. In addition, the magnetic Cu 1 Fe 0.5 Al 0.5 -LDO catalyst showed certain stability and reproducibility after 5 consecutive repeated reactions. The excellent degradation of TBBPA was mainly attributed to the existence of a large amount of SO 4 •– , •OH and 1 O 2 active species in the Cu 1 Fe 0.5 Al 0.5 -LDO/PMS system. The activation mechanism of PMS and the degradation pathway of TBBPA were proposed. Toxicity Assessment Software Tool (TEST) indicated that the Cu 1 Fe 0.5 Al 0.5 -LDO/PMS system can effectively reduce the harm and risk of TBBPA to the overall environment. This work provided a possible novel idea for the application of Cu 1 Fe 0.5 Al 0.5 -LDO/PMS system in the degradation of brominated phenolic organic pollutants in actual water.

Ion solvation and association and water structure in an aqueous cerium (III) chloride solution in the gigapascal pressure range.

X-ray diffraction measurements are performed on a 1m (= mol kg-1) CeCl3 aqueous solution over a temperature range of 300-600K and a pressure range of 0.1MPa to 4 GPa. The experimental interference functions are analyzed by an empirical potential structure refinement (EPSR) modeling. The Ce3+ coordinates water molecules in a tricapped trigonal prism configuration under the ambient condition. The number of water molecules around Ce3+ changes from 8.8 at 0.1MPa/300K to 11.5 at 4 GPa/600K. The number of water molecules around Cl- changes drastically from 10 under the ambient condition to 17 at 4 GPa/600K. The tetrahedral-like network structure of water under the ambient condition is transformed toward a simple liquid-like packing in the GPa pressure range. The corresponding coordination number is increased from 4.3 in the ambient condition to 9.7 at 4 GPa/600K. The Ce3+-Cl- association decreases with increasing pressure.

Syntheses, Polymorphic Transformations, and Functions of Ionic Crystals Based on Mononuclear Bismuth(III) Complexes and Polyoxometalates

AbstractThe controlled assembly of molecules, ions, and ligands as building blocks based on crystal engineering leads to various functional crystalline solids. In particular, polyoxometalates (POMs), which are anionic metal oxide clusters, have been a popular motif in crystal engineering. To revisit simple mononuclear metal complexes as counter cations of POMs, seven ionic crystals based on Keggin‐ or Dawson‐type POMs with mononuclear bismuth(III) complexes as counter cations were synthesized. The bismuth(III) center exhibited triangular dodecahedron, square antiprism, or pseudo‐cubic eight‐coordination geometries, with dimethyl sulfoxide or N,N‐dimethylformamide as ligands. The ionic crystals showed polymorphic transformation depending on the synthetic or recrystallization conditions. As a method for exploring functionality, proton conductivities of the ionic crystals were measured under humidified conditions. The ionic crystals with high porosity, tertiary amine moieties, or coordination water exhibited high proton conductivities, and large activation energies indicate that protons are transferred mainly with water molecules via the vehicle mechanism.

Crystal structure and DNA cleavage properties of a vanadium complex [NH4][VO(O2)2(pm-im)]⋅3H2O containing 2-(1H-imidazol-2-yl)pyrimidine ligand

A new diperoxovanadium compound, [NH4][VO(O2)2(pm-im)]⋅3H2O (1) (pm-im = 2-(1H-imidazol-2-yl)pyrimidine), has been prepared from aqueous solution and its crystal structure has been determined by single-crystal X-ray diffraction. It belongs to the monoclinic P21/n space group with a = 6.798(4) Å, b = 11.468(6) Å, c = 18.073(9) Å, β = 96.020(6)°, V = 1401.3(13) Å3, and Z = 4. The asymmetric unit of 1 consists of a diperoxovanadium [VO(O2)2(pm-im)]− anion, one free NH4 + counterion, and three lattice water molecules, which are further stacked to form a three-dimensional (3D) supramolecular structure through intra- and intermolecular hydrogen bond interactions. The solution stability of the ion ([VO(O2)2(pm-im)]−) was explored using a combination of multinuclear (1H, 13C, and 51V) magnetic resonance and variable temperature NMR in a 0.15 mol L−1 NaCl/D2O solution that mimics physiological conditions. Additionally, the compound exhibits significant DNA cleavage ability under light, and the electrophoretic result shows that the super helix DNA seems to be directly cleaved into single stranded DNA.

Intercalation of Ca into a Highly Defective Manganese Oxide at Room Temperature

The utilization of oxide frameworks as intercalation cathodes for nonaqueous Ca-ion batteries potentially unlocks a new energy-storage system that delivers high energy density. However, the slow kinetics of Ca2+ in oxide electrodes strongly handicaps their activity and reversibility at room temperature. Herein, nanocrystals of layered MnOx containing a high concentration of atomic defects and lattice water are shown to have remarkable electrochemical activity toward Ca2+, amounting to a capacity of ∼130 mAh/g at room temperature. Multimodal characterization revealed the notable degree of intercalation by probing the structural, compositional, and redox changes undertaken by the defective MnOx nanocrystals. The results suggest that the existence of atomic defects and lattice water played a role in improving Ca2+ diffusivity in the oxide. These outcomes reaffirm the prospects for functional Ca-ion batteries using oxide cathodes under moderate conditions.

Improved oxygen balance and effective energy density by coligand and dehydration strategy: Synthesis and characterization of two new energetic coordination polymers

Based on the excellent energetic ligand of N, N-bis(1H-tetrazole-5-yl)-amine (H2bta) and coligand of oxalic acid (oa), Cu(Ⅱ) as the metal center ion, a new energetic coordination polymer (ECP), {[Cu2(bta)2(oa)(H2O)2]∙4H2O}n (1), was synthesized by hydrothermal method. Single crystal X-ray diffraction indicates that 1 possess 3D supramolecular configuration. Due to the existence of a large number of lattice water and coordination water molecules in 1, however, the effective energy density of 1 is limited. To further improve the performance of 1, according to its thermal decomposition behavior, we dehydrated 1 at 280 °C to obtain a new ECP [Cu2(bta)2(oa)]n (2). The thermodynamic parameter of the decomposition process of 1 was discussed by Kissinger's and Ozawa's methods. Sensitivity tests show that 2 is more sensitivity to impact stimuli than 1, reflecting guest-dependent energy and sensitivity of ECPs. The theoretical calculation results show that 1 possess good detonation performances. The promotion effects of two ECPs on the combustion decomposition of ammonium perchlorate were studied using a differential scanning calorimetry method. Experimental results showed that 1 and 2 can be used as high energy density materials in the field of combustion promoter and the insensitive 1 can be regarded as a safe form for mass storge and transportation of sensitive 2.

Synthesis and structural characterization of a new heterometallicmolybdate coordination polymer based on a µ3-bridging amino alcohol

Abstract The reaction of Na2MoO4·2H2O with 2-amino-2-(hydroxymethyl)propane-1,3-diol (LH) in water at room temperature results in the formation of the heterometallic coordination polymer [Mo2O6L2(Na2(H2O)4)]·2H2O 1 (L = 2-amino-3-hydroxy-2-(hydroxymethyl)propan-1-olato). The structure of 1 consists of a neutral (Mo2O6) unit located on an inversion center. The Mo atoms exhibit hexa-coordination and are bonded to two terminal and two bridging oxido ligands, an alkoxide oxygen and the amine N atoms of an anionic ligand L– resulting in the formation of an edge-sharing {Mo2O8N2} bioctahedron. The Na+ cations of a centrosymmetric bis(μ2-aqua)-bridged (Na2(H2O)4)2+ unit are penta-coordinated and bonded to two symmetry related L– ligands via the oxygen atoms of their OH groups. The µ3-bridging tetradentate binding mode of L– results in the formation of a two-dimensional heterometallic coordination polymer. The constituents of 1 viz. (Mo2O6), (L)–, (Na2(H2O)4)2+ and lattice water molecules are interlinked with the aid of three varieties of hydrogen bonding interactions. The corresponding tungstate reported recently has been obtained through a similar synthetic protocol and is isostructural.

Synthesis and structures of copper coordination polymers incorporating a bis-pyridyl-bis-amine ligand

A new bis-pyridyl-bis-amine ligand, namely N,Nʹ-bis(pyridin-3-ylmethyl)-1,2-ethylenediamine (bpmen), has assembled with Cu(II) salts of sulfate and nitrate to yield corresponding Cu coordination polymers {[Cu(H2bpmen)(H2O)4](SO4)2∙2H2O}n (1) and {[Cu(bpmen)](NO3)}n (2). Compound 1 has a cationic simple coordination chain structure, where the Cu(II) center has an octahedral geometry consisting of N2O4 donors and the protonated H2bpmen2+ ligand suits a bis-monodentate coordination mode with the –CH2NHCH2CH2NHCH2- backbone in a GGTGG conformation, where G and T devoted as gauche and trans conformations, respectively. Numerous hydrogen-bonding interactions make 1 to form a three-dimensional neutral supramolecular hydrogen-bonded net. For synthesizing 2, the starting Cu(II) cations are reduced to Cu(I) cations by bpmen ligands during the assembly process. Compound 2 has a cationic double-stranded zigzag chain structure, where the Cu(I) center has a tetrahedral geometry composing of N4 donors and the bpmen ligand adopts a chelating-bridging mode with the –CH2NHCH2CH2NHCH2- backbone in a TGGTT conformation. A variety of framework … nitrate hydrogen-bonding interactions results in a two-dimensional neutral supramolecular hydrogen-bonded layer. Thermogravimetric (TG) analysis showed that the coordination frameworks of 1 and 2 after releasing lattice and coordination water molecules are thermally stable up to approaching 252 and 210 ​°C, respectively. Solid-state emission spectra of 1 and 2 exhibited no and weak luminescence emission bands, respectively, upon irradiation.

Structure directing roles of weak noncovalent interactions and charge-assisted hydrogen bonds in the self-assembly of solvated podands: an example of an anion-assisted dimeric water capsule

A 4-aminopyridinium-functionalized mesitylene-based podand could facilitate the formation of a dimeric capsular assembly due to the complementary hydrogen bonding mediated by bromide counterions and lattice water.

Operando XRD and electrogravimetry coupling to analyze species transfers during redox processes in Ni/Fe-layered double hydroxide

Redox reactions occurring in NiFe-LDH nanoplatelets polarized in LiOH solution lead to anion exchange, cation (electro)sorption and water molecule transfer.

Reversible Crystal−Amorphous Transformation Assisted by Loss and Adsorption of Coordination Water Molecules and Ionic Conduction in Two Isomorphous Decavanadate-Type Polyoxometalates

Reversible Crystal−Amorphous Transformation Assisted by Loss and Adsorption of Coordination Water Molecules and Ionic Conduction in Two Isomorphous Decavanadate-Type Polyoxometalates

Stable terbium metal-organic framework with turn-on and blue-shift fluorescence sensing for acidic amino acids (L-aspartate and L-glutamine) and cations (Al3+ and Ga3+).

A terbium-based metal-organic framework, namely {[Tb2(ADIP)(H2ADIP)(HCOOH)(H2O)2]·2DMF·2H2O}n (Tb-MOF, H4ADIP = 5,5'-(anthracene-9,10-diyl) diisophthalic acid), was synthesized and characterized. The single-crystal structure analysis shows that the Tb-MOF crystallizes in the C2/C space group in the monoclinic system and its asymmetric unit contains two TbIII ions, one ADIP4-, one H2ADIP2-, one coordinating formic acid and two coordination water molecules. Tb-MOF has a three-dimensional porous structure with a porosity of 41.5%. Tb-MOF is a highly selective and sensitive fluorescence turn-on and blue-shift sensor for L-aspartate (Asp), L-glutamine (Glu), Al3+ and Ga3+with detection limits of 0.25, 0.23, 0.069 and 0.079 μM, respectively. Experimental studies and theoretical calculations show that the sensing process is mainly attributed to the energy transfer and the absorbance caused enhancement (ACE) mechanism. Therefore, Tb-MOF is a good multi-response fluorescence sensor for acidic amino acids and Al3+, Ga3+cations.

Electrostatic force-driven lattice water bridging to stabilize a partially charged indium MOF for efficient separation of C2H2/CO2 mixtures

Remaining charge on the indium sites of MOF FJU-118 has an electrostatic force on the –CC− bond of C2H2 molecules for the selective separation of C2H2/CO2 mixtures.