•Copper(II) complexes of 8-quinolinylazo-6-aminouracil and pseudohalides were studied.•Crystal structures were evaluated.•Electronic spectra and TD-DFT computations were performed.•Weak ...antiferromagnetic interactions were evidenced by the study of magnetism.•Anti-plant pathogens activities of the copper(II) complexes were studied.
Two Cu(II)-complexes were synthesized using 1,3-dimethyl-5-(8′-quinolinylazo)-6-aminouracil (H2L) ligand in combination with thiocyanide (SCN−) and azide (N3−) pseudohalides as co-ligands. The thiocyanide (SCN−) co-ligand guided to form monomeric aquo-isothiocyanato-Cu(II) complex, CuII(HL)(NCS)(H2O) (1) of H2L. Under similar reaction condition, the azide (N3−) co-ligand led to form polymeric azido-Cu(II) complex, CuII(L′)(N3)n, (2) of HL′, where HL′ was an in-situ generated new ligand, 1,3-dimethyl-(5-(8′-quinolinylazo)-6-hydroxouracil (HL′) from H2L. Both are tridentate ligands with different uracil-donor sites (H2L: NqNaNu, HL′: NqNaOu). The complexes are monoclinic with space groups C2/c (Z = 8) and P21/n (Z = 4) for 1 and 2, respectively. They possess slightly distorted square-pyramidal coordination around CuII ions with elongation at the axial sites (Cu1-O3 (water) bond is 2.2698(13)Å for 1 and Cu1-Oμ-uracil bond is 2.5525(13)Å for 2). The polymeric nature of 2 is availed through one of the exocyclic-C = O groups of HL′, making Cu…Cu spacing to 7.9973(3)Å. Direct current (dc) variable-temperature magnetic susceptibility measurements on polycrystalline samples of 1 and 2 were carried out in the temperature range 1.8-300 K. The 1 is devoid of any significant interaction between the mononuclear units. Magnetic properties show weak ferromagnetic exchange coupling within the chain (J = 0.61 cm−1) in 2. The TD-DFT study reveals that ILCT, LMCT and d-d types of electronic transitions are involved in both the complexes. The evaluated biological efficacy of the compounds against plant pathogens it is revealed that the complex 1 has an antibacterial and complex 2 has antifungal properties.
6-Aminouracil-azo-8′-quinoline (H2L) ligand in DMF forms two axially-elongated square-pyramidal Cu(II)-complex withthiocyanide (SCN−) and azide (N3−) pseudohalideco-ligands. The thiocyanide-Cu(II) complex is amonomer with paramagnetic and anti-bacterial properties, whereas the azide-Cu(II) complex is a polymer with weak ferromagnetism and anti-fungal properties.
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•1-D Cu(tba)2(H2O)⋅2H2O (abbreviated as 1D-Cu, tba = 3-1,2,4triazol-1-yl-benzoic acid) complex nanoparticles were synthesized using the hydrothermal method.•Photocatalytic degradation ...of methylene blue and indole-3-acetic acid by 1D-Cu nanoparticles were studied.•Synergetic effect of 1D-Cu complex and H2O2 was found in the photocatalytic process.•Kinetic behavior and possible mechanism of photocatalytic processes were investigated.
One-dimensional complex Cu(tba)2(H2O)⋅2H2O (abbreviated as 1D-Cu, tba = 3-1,2,4triazol-1-yl-benzoic acid) micropowders were synthesized using the hydrothermal method, and further characterized by powder X-ray diffraction, elemental analysis, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Fourier-transform infrared (FT-IR) spectroscopy and UV–vis diffuse reflectance spectra. The photodegradation of methylene blue (MB) and indole-3-acetic acid (IAA) were studied under UV irradiation using 1D-Cu as catalysts in the presence of H2O2. The degradation efficiency of MB was up to 84.9 % after irradiating for 90 min under UV light, while the degradation efficiency of IAA was over 60.4 % after irradiating for 4 h. Reaction kinetics studies showed that both MB and IAA were in accordance with the pseudo-first-order reaction kinetics in the photodegradation process, and the t1/2 for MB and IAA was 31.2 and 183.4 min, respectively. FT-IR and powder X-ray diffraction tests suggested that 1D-Cu catalyst exhibited excellent stability toward the photocatalytic reactions. Besides, the mechanism of photocatalytic reaction catalyzed by 1D-Cu was discussed, and the synergistic effect of 1D-Cu and H2O2 was also studied. This study provides a 1D-Cu/H2O2 catalytic system for the photocatalytic degradation of harmful organic dyes and phytohormones in water.
•Redox properties of tetrapyridylalkylamine Cu(II) complexes with diimines.•Oxygen reduction catalysis by tetrapyridylalkylamine Cu(II) complexes with diimines.•Catalytic oxygen reduction mechanism ...by tetrapyridylalkylamine Cu(II) complexes with diimines.
Oxygen reduction reaction (ORR) is important in artificial energy conversion systems such as fuel cells. However, it is kinetically sluggish. It is thereby highly desirable to develop ORR catalysts to improve the efficiency of energy conversion. In this work, three copper(II) complexes based on the hexadentate tetrapyridylalkylamine N,N,N’,N’-tetrakis(2-pyridyl-methyl)-1,4-butanediamine (tpbn), namely Cu2(tpbn)(CH3OH)4(ClO4)2(ClO4)2 (Cu-tpbn), Cu2(tpbn)(bpy)2(ClO4)4.2CH3COCH3 (Cu-tpbn-bpy, bpy = 2,2′-bipyridine), and Cu2(tpbn)(Me2bpy)2(ClO4)4.3CH3CN (Cu-tpbn-Me2bpy, Me2bpy = 4,4′-dimethyl-2,2′-bipyridine), were prepared and their catalytic properties for ORR studied. All three complexes were homogeneous electrocatalysts for ORR in neutral phosphate buffer solutions. The ORR mediated by Cu-tpbn-Me2bpy had the most positive onset potential of 0.461 V vs RHE. In the applied potential window of -0.19 – 0.50 V vs RHE, Cu-tpbn boosted the stepwise four-electron ORR to mainly produce H2O, whereas Cu-tpbn-bpy and Cu-tpbn-Me2bpy mediated the ORR to mainly generate H2O2. The rate constants for the ORR to H2O promoted by Cu-tpbn, Cu-tpbn-bpy and Cu-tpbn-Me2bpy were 1.2 × 103 s−1, 3.2 × 10 s−1 and 7.8 × 10 s−1, respectively. The foot-of-the-wave analysis showed that the turnover frequencies for the reduction of O2 to H2O2 mediated by Cu-tpbn, Cu-tpbn-bpy and Cu-tpbn-Me2bpy were 1.5 × 104 s−1, 7.5 × 10 s−1 and 2.7 × 102 s−1, respectively. Meanwhile, complexes Cu-tpbn-bpy and Cu-tpbn-Me2bpy were more stable than Cu-tpbn. This work unveiled that the catalytic activity and the product selectivity of the ORR were greatly associated with the denticity, the steric effect and the electronic property of the organic ligands.
Three tetrapyridylalkylamine copper(II) complexes were homogeneous catalysts for oxygen reduction reaction (ORR). The main product of ORR mediated by the Cu-tpbn systems was directed from H2O to H2O2 via the incorporation of the diimine ligands. Display omitted
wo unusual Cu(II) complexes {Cu(L1)}2 (1) and Cu2(L2) (2), with an asymmetric salamo-type bisoxime ligand H2L1 were synthesized and characterized by elemental analyses, UV–Vis, fluorescent spectra, ...Hirshfeld surface analyses and single-crystal X-ray diffraction analyses. For the complex 1, two Cu(II) ions are penta-coordinate by N2O2 donor atoms from the (L1)2− unit and one bridged phenol oxygen atom from another (L1)2− unit. Complex 1 does not have intermolecular hydrogen bonds, formed an isolated zero dimensional structure. Meanwhile, for the complex 2, an unexpected ligand H4L2 was synthesized by aldol condensation reaction of H2L1 and acetone upon coordination, then the new ligand and Cu(II) ions combined, formed a highly symmetrical structure, and two Cu(II) ions of the complex 2 have tetra-coordinate environment. With the help of intermolecular hydrogen bonding CH⋯O interactions, a self-assembled infinite 1D supramolecular structure was formed. Meanwhile, the photophysical spectra and Hirshfeld surface analyses of the complexes 1 and 2 were also measured and discussed.
Through the self-assembly of an asymmetric salamo-type bioxime ligand H2L1 with Cu(OAc)2·2H2O, two unusual Cu(II) complexes, {Cu(L1)}2 (1) and Cu2(L2) (2) were obtained and characterized structurally. Meanwhile, the photophysical spectra and Hirshfeld surface analyses of the complexes 1 and 2 were also discussed. Display omitted
•Two unusual Cu(II) salamo-type complexes {Cu(L1)}2 and Cu2(L2) were synthesized and characterized structurally.•The unexpected ligand H4L2 was obtained by aldol condensation reaction of H2L1 and acetone upon coordination.•The intermolecular interactions presented in the total crystal structure were discussed by Hirshfeld surface analysis.
•N-Arylation of sulfonamides with arylboronic acids using PS-tet-Cu(II) in water.•The catalyst was characterized using the powder XRD, SEM, EDS and FT-IR spectroscopy.•The catalyst can be recovered ...and reused several times without significant loss of its catalytic activity.•Operational simplicity, green reaction conditions, short reaction times and high yields.
This paper reports on the synthesis and use of nanopolymer supported copper (II) complex, as separable catalysts for N-arylation of sulfonamides with arylboronic acids in water. This method has the advantages of high yields, elimination of homogeneous catalysts, green reaction conditions, simple methodology and easy work up. The catalyst can be recovered and reused several times without significant loss of its catalytic activity. The catalyst was characterized using the powder XRD, SEM, EDS and FT-IR spectroscopy.
•Synthesis and characterization of complex Cu-tpmen.•Redox properties of complex Cu-tpmen.•Electrocatalytic oxygen reduction by complex Cu-tpmen.•Electrocatalytic water oxidation by complex Cu-tpmen.
...The development of catalysts for oxygen reduction reaction (ORR) and water oxidation reaction (WOR) is important for promoting the utilization of renewable energy sources. Catalysts based on Earth-abundant metals are low-cost and benefit the widespread use. Herein a mononuclear copper complex Cu(tpmen)(ClO4)2 (Cu-tpmen) of the pentadentate pyridylalkylamine ligand N,N,N’-tris(2-pyridylmethyl)-N’-methylethylenediamine (tpmen) was synthesized and characterized. The electrochemical properties and the catalysis for the ORR and the WOR by Cu-tpmen in aqueous solutions were studied. Cu-tpmen in pH 7.0 0.1 M phosphate buffer solution (PBS) can boost the ORR with an onset potential at 0.47 V versus the reversible hydrogen electrode (RHE), generating mainly H2O2. The foot-of-the-wave analysis showed that turnover frequency (TOF) of the reduction of O2 to H2O2 mediated by Cu-tpmen was 6.5 × 104 s−1. Meanwhile, Cu-tpmen exhibited catalytic activities for the WOR with the TOF values of 50.9 s−1 (at pH 7.0) and 8.4 s−1 (at pH 10.5). Cu-tpmen was thus a homogeneous bidirectional ORR/WOR catalyst and the reaction mechanisms were proposed. The synergic effect of the flexibility and the electron-donating ability of tpmen benefited the bidirectional catalytic properties of Cu-tpmen.
The bidirectional catalytic properties of a copper(II) complex benefited from the synergic effect of the flexibility and the electron-donating ability of the polypyridine ligand.
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A new binuclear Cu (II) complex, Cu2L2 (NO3)4 (3) has been synthesized via complexation of Cu(NO3)2·3H2O with coumarin -3- formyl - (3- (aminomethyl) pyridine (L). The crystal structure of L and the ...complex (3) have been determined by single-crystal X-ray diffraction. The molecular units of L are linked into one dimensional parallel to the b direction via N–H⋯O and C–H⋯O hydrogen bonds. The Cu (II) complex (3) has a 2D supramolecular structure because of the C–H⋯O and C–H⋯N hydrogen bonds. The Hirshfeld surface analysis 41 was performed to provide further insight into the packing and intermolecular contacts of 3. DFT calculations are performed to show that the BS singlet state of the complex (3) is the ground state and to investigate the bonding situation of it.
A new coumarin derivate coumarin -3- formyl - (3- (aminomethyl) pyridine) (2) and its dinuclear copper (II) complex Cu2L2(NO3)4 (3) have been synthesized and structurally determined. DFT calculations are performed to show that the BS singlet state of the complex (3) is the ground state and to investigate the bonding situation of it. Display omitted
•A new kind of binuclear Cu (II) complex based on coumarin-amide was synthesized.•The crystal structure of this compound was measured.•DFT calculations show that the BS singlet state of 3 is the ground state and to investigate the bonding situation of it.
A novel mixed ligand Cu(II) complex, Cu2(C8H4O2SF3)2(C9H6NO)2, has been synthesized and characterized by FT-IR, UV–visible, SEM and EDAX techniques. A single crystal X-ray structure determination ...revealed the centrosymmetric dinuclear form of the Cu(II) complex and a distorted square pyramidal geometry around the Cu(II) centre. The Cu(II) complex exhibits various intermolecular interactions, leading to the construction of R22(16), R22(10) and R22(20) supramolecular synthons. The existence of intermolecular interactions is supported by Hirshfeld surface analysis and quantified by 2D fingerprint plots. In addition, the 3D topology of the molecular packing is visualized through energy frameworks, revealing the predominance of dispersion energy over other interaction energies. DFT calculations results well supported the experimental values. Further, the Cu(II) complex was evaluated against MRSA and these results were validated by molecular docking studies for penicillin-binding protein 2, with an excellent binding score of −8.0 kcal/mol.
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As an essential class of heterocyclic derivatives, 8-hydroxyquinoline(HQ) and 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione (TFTB) have a broad range of pharmaceutical applications and they are found to be excellent precursors for metal complexes and crystal engineering. The novel mixed ligand Cu(II) complex Cu2(C8H4O2SF3)2(C9H6NO)2 has been synthesized using a metal salt and the above ligands in a 1:1:1 M ratio and characterized by FT-IR, UV–visible, SEM and EDAX techniques. Single crystal X-ray structure analysis reveals a centrosymmetric dinuclear form of the Cu(II) complex, linked by the obtuse phenolate oxygen atom, and the central Cu(II) ion adopts a distorted square pyramidal coordination geometry. The Cu(II) complex exhibits various intermolecular interactions, leading to the construction of R22(16), R22(10) and R22(20) supramolecular synthons. The existence of intermolecular interactions is supported by Hirshfeld surface analysis and quantified by 2D fingerprint plots. In addition, the 3D topology of the molecular packing is visualized through energy frameworks, which reveal the predominance of dispersion energy over other interaction energies. DFT calculations have been performed for the mixed ligand Cu(II) complex to study the optimal geometry, related reactive parameters and the HOMO-LUMO energy gap (0.8232 eV). Further, the Cu(II) complex was evaluated against MRSA and showed an MIC value of 15 μg/mL. A time-killing assay for the Cu(II) complex was performed to study the antimicrobial effect with respect to time. A molecular docking study revealed the binding affinity of the Cu(II) complex to penicillin-binding protein 2, with an excellent binding score of −8.0 kcal/mol.
•Two copper complexes containing tridentate ligand was synthesized.•The complexes are halochromic, solvatochromic and thermochromic.•Square-pyramid geometry of complex was confirmed by X ray and DFT ...calculation.•Reversible structural change in solution is responsible for observed chromotropism.
Two copper (II) mononuclear complexes with the general formula Cu(HL)X2, which L = N-2-ethanolpicolylamine and X = Cl, Br, were synthesized and characterized by elemental analysis infrared, electronic absorption spectroscopy techniques, and conductivity method. The distorted square pyramidal geometry of Cu(HL)Cl2 was confirmed by the density functional theory level (DFT) calculation and X-ray crystallography. The complexes are soluble in polar solvents and are chromotropic. It was found both complexes have a similar identity in aqueous solution due to dissociation of halides and hydration. Their chromotropism behavior, including solvato-, thermos- and halochromism, was investigated using visible absorption spectroscopy. The original green complex displayed a reversible color change to blue in alkaline and almost colorless in acidic solutions. The pH effect on the visible absorption spectrum of the complex was studied that functions as pH-induced “off–on-off” switches triggered by the deprotonation of ligand in an alkaline aqueous solution and protonation along with loss of the ligand HL in an acidic medium. The complex also exhibited thermochromism and solvatochromism due to solvation and structural change. Further computational analysis of the electronic structure of the complex in different solvents was executed to gain a deeper insight into the properties associated with molecular orbitals. Its electronic spectrum was analyzed, and bands were assigned through the time-dependent density functional theory level (TDDFT) calculation, together with DFT-based molecular modeling
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•The Ag(CN)2−3 trimer was found in Cu(Dach)2-Ag(CN)2-Cu(Dach)2Ag(CN)23 complex.•This entity is stabilized by unsupported argentophilic interaction.•MP2 interaction energy for this ...trimer is equal to −6.95 kcal/mol.•Energy decomposition revealed the prominent role of electrostatics and dispersion.•Normal vibrations of the Ag⋯Ag⋯Ag interaction confirmed its weak character.
Crystal structure study of a copper(II) complex of cis-1,2-diaminocyclohexane (Dach), Cu(Dach)2-Ag(CN)2-Cu(Dach)2Ag(CN)23 (1) reveals the presence of unsupported Ag⋯Ag⋯Ag interactions with the interatomic Ag⋯Ag distance of 3.230 Å. Detailed HF, MP2 and BLYP-D3 theoretical investigations of Ag(CN)2−3 trimer, together with AIM, NCI and EDA analyses verified these interactions as noncovalent AgAg bonds with the magnitude of a weak hydrogen bond, mainly electrostatically and dispersively driven.
