Synthesis, Structural Characterization, Hirschfeld Surface Analysis, Density Functional Theory, and Photocatalytic CO2 Reduction Activity of a New Ca(II) Complex with a Bis-Schiff Base Ligand.

A new bis-Schiff base (L) Ca(II) complex, CaL, was synthesized by the reaction of calcium perchlorate tetrahydrate, 1,3-diamino-2-hydroxypropane, and 2-formyl phenoxyacetic acid in an ethanol-water (v:v = 2:1) solution and characterized by IR, UV-vis, TG-DTA, and X-ray single crystal diffraction analysis. The structural analysis indicates that the Ca(II) complex crystallizes in the monoclinic system, space group P121/n1, and the Ca(II) ions are six-coordinated with four O atoms (O8, O9, O11, O12, or O1, O2, O4, O6) and two N atoms (N1, N2, or N3, N4) of one bis-Schiff base ligand. The Ca(II) complex forms a tetramer by intermolecular O-H…O hydrogen bonds. The tetramer units further form a three-dimensional network structure by π-π stacking interactions of benzene rings. The Hirschfeld surface of the Ca(II) complex shows that the H…H contacts represent the largest contribution (41.6%) to the Hirschfeld surface, followed by O…H/H…O and C…H/H…C contacts with contributions of 35.1% and 18.1%, respectively. To understand the electronic structure of the Ca(II) complex, the DFT calculations were carried out. The photocatalytic CO2 reduction test of the Ca(II) complex exhibited a yield of 47.9 µmol/g (CO) and a CO selectivity of 99.3% after six hours.

Synthesis, Structural Characterization, and Hirschfeld Surface Analysis of a New Cu(II) Complex and Its Role in Photocatalytic CO2 Reduction.

A new Cu(II) complex, [CuL1L2(CH3COO)2(H2O)]·H2O, was synthesized by the reaction of Cu(CH3COO)2·H2O, 6-phenylpyridine-2-carboxylic acid (HL1), and 4-[5-(pyridin-4-yl)-1,3,4-oxadiazol-2-yl]pyridine (L2) in ethanol-water (v:v = 1:1) solution. The Cu(II) complex was characterized using elemental analysis, IR, UV-vis, TG-DTA, and single-crystal X-ray analysis. The fluorescence properties of the copper complex were also evaluated. The structural analysis results show that the Cu(II) complex crystallizes in the triclinic system with space group P-1. The Cu(II) ion in the complex is five-coordinated with one O atom (O2) and one N atom (N1) from one 6-phenylpyridine-2-carboxylate ligand (L1), one N atom (N2) from 4-[5-(pyridin-4-yl)-1,3,4-oxadiazol-2-yl]pyridine ligand (L2), one O atom (O4) from acetate, and one O atom (O5) from a coordinated water molecule, and it adopts a distorted trigonal bipyramidal geometry. Cu(II) complex molecules form a two-dimensional layer structure through intramolecular and intermolecular O-H…O hydrogen bonding. The two-dimensional layer structures further form a three-dimensional network structure by π-π stacking interactions of aromatic rings. The analysis of the Hirschfeld surface of the Cu(II) complex shows that the H…H contacts made the most significant contribution (46.6%) to the Hirschfeld surface, followed by O…H/H…O, N…H/H…N and C…H/H…C contacts with contributions of 14.2%, 13.8%, and 10.2%, respectively. In addition, the photocatalytic CO2 reduction using Cu(II) complex as a catalyst is investigated under UV-vis light irradiation. The findings reveal that the main product is CO, with a yield of 10.34 µmol/g and a selectivity of 89.4% after three hours.

Synthesis, Structural Characterization, Hirschfeld Surface Analysis and Photocatalytic CO2 Reduction Activity of a New Dinuclear Gd(III) Complex with 6-Phenylpyridine-2-Carboxylic Acid and 1,10-Phenanthroline Ligands.

A new dinuclear Gd(III) complex was synthesized and named [Gd2(L)4(Phen)2(H2O)2(DMF)2]·2H2O·2Cl (1). Here, L is the 6-phenylpyridine-2-carboxylate anion, Phen represents 1,10-phenanthroline, DMF is called N,N-dimethylformamide, and Cl- is the chloride anion, which is characterized by IR and single crystal X-ray diffraction analysis. The structural analysis reveals that complex (1) is a cation-anion complex, and each Gd(III) ion is eight-coordinated with four O atoms (O1, O5, O2a, O4a, or O1a, O2, O4, O5a) of four different bidentate L ligands, two O atoms (O6, or O6a) of DMF molecules, two N atoms (N1, N2, or N1a, N2a) of Phen ligands, and two O atoms (O3 or O3a) of coordinated water molecules. Complex (1) forms the three-dimensional π-π stacking network structure with cavities occupied by chloride anions and uncoordinated water molecules. The Hirschfeld surface of the complex (1) shows that the H···H contacts represented the largest contribution (48.5%) to the Hirschfeld surface, followed by C···H/H···C and O···H/H···O contacts with contributions of 27.2% and 6.0%, respectively. To understand the electronic structure of the complex (1), the DFT calculations have been performed. The photocatalytic CO2 reduction activity shows complex (1) has excellent catalytic activity with yields of 22.1 µmol/g (CO) and 6.0 µmol/g (CH4) after three hours. And the selectivity of CO can achieve 78.5%.

A Review on Cu2O-Based Composites in Photocatalysis: Synthesis, Modification, and Applications.

Photocatalysis technology has the advantages of being green, clean, and environmentally friendly, and has been widely used in CO2 reduction, hydrolytic hydrogen production, and the degradation of pollutants in water. Cu2O has the advantages of abundant reserves, a low cost, and environmental friendliness. Based on the narrow bandgap and strong visible light absorption ability of Cu2O, Cu2O-based composite materials show infinite development potential in photocatalysis. However, in practical large-scale applications, Cu2O-based composites still pose some urgent problems that need to be solved, such as the high composite rate of photogenerated carriers, and poor photocatalytic activity. This paper introduces a series of Cu2O-based composites, based on recent reports, including pure Cu2O and Cu2O hybrid materials. The modification strategies of photocatalysts, critical physical and chemical parameters of photocatalytic reactions, and the mechanism for the synergistic improvement of photocatalytic performance are investigated and explored. In addition, the application and photocatalytic performance of Cu2O-based photocatalysts in CO2 photoreduction, hydrogen production, and water pollution treatment are discussed and evaluated. Finally, the current challenges and development prospects are pointed out, to provide guidance in applying Cu2O-based catalysts in renewable energy utilization and environmental protection.

S-Scheme 2D/2D Heterojunction of ZnTiO3 Nanosheets/Bi2WO6 Nanosheets with Enhanced Photoelectrocatalytic Activity for Phenol Wastewater under Visible Light.

The pollution of phenol wastewater is becoming worse. In this paper, a 2D/2D nanosheet-like ZnTiO3/Bi2WO6 S-Scheme heterojunction was synthesized for the first time through a two-step calcination method and a hydrothermal method. In order to improve the separation efficiency of photogenerated carriers, the S-Scheme heterojunction charge-transfer path was designed and constructed, the photoelectrocatalytic effect of the applied electric field was utilized, and the photoelectric coupling catalytic degradation performance was greatly enhanced. When the applied voltage was +0.5 V, the ZnTiO3/Bi2WO6 molar ratio of 1.5:1 had highest degradation rate under visible light: the degradation rate was 93%, and the kinetic rate was 3.6 times higher than that of pure Bi2WO6. Moreover, the stability of the composite photoelectrocatalyst was excellent: the photoelectrocatalytic degradation rate of the photoelectrocatalyst remained above 90% after five cycles. In addition, through electrochemical analysis, XRD, XPS, TEM, radical trapping experiments, and valence band spectroscopy, we found that the S-scheme heterojunction was constructed between the two semiconductors, which effectively retained the redox ability of the two semiconductors. This provides new insights for the construction of a two-component direct S-scheme heterojunction as well as a feasible new solution for the treatment of phenol wastewater pollution.

A Luminescent Cd-MOF Used as a Chemosensor for High-Efficiency Sensing of Fe3+, Cr(IV), Trinitrophenol, and Colchicine.

A Cd-MOF was constructed based on 3,5-bis(4-carboxyphenyl) pyridine under solvothermal conditions. Its structure and phase purity were verified by single-crystal X-ray diffraction. Thereafter, some studies on the morphology, structure, and luminescent properties of the compound were carried out. The compound exhibited a highly sensitive response to Fe3+, Cr(IV), trinitrophenol (TNP), and colchicine based on the fluorescence-quenching mechanism. The possible mechanism of luminescence quenching was discussed in detail.

Boosting electrocatalytic performance via electronic structure regulation for acidic oxygen evolution.

High-purity hydrogen produced by water electrolysis has become a sustainable energy carrier. Due to the corrosive environments and strong oxidizing working conditions, the main challenge faced by acidic water oxidation is the decrease in the activity and stability of anodic electrocatalysts. To address this issue, efficient strategies have been developed to design electrocatalysts toward acidic OER with excellent intrinsic performance. Electronic structure modification achieved through defect engineering, doping, alloying, atomic arrangement, surface reconstruction, and constructing metal-support interactions provides an effective means to boost OER. Based on introducing OER mechanism commonly present in acidic environments, this review comprehensively summarizes the effective strategies for regulating the electronic structure to boost the activity and stability of catalytic materials. Finally, several promising research directions are discussed to inspire the design and synthesis of high-performance acidic OER electrocatalysts.

A novel tetranuclear Cu(ii) complex for DNA-binding and in vitro anticancer activity.

A novel tetranuclear Cu(ii) complex (TNC) was successfully synthesized and characterized by X-ray single crystal diffraction. The interaction of the complex with calf thymus DNA (CT-DNA) has been studied by UV-vis absorption titration, fluorescence technology and molecular docking. The results indicated that TNC could bind to the DNA through an intercalative mode. The agarose gel electrophoresis experiment showed that TNC could cleave supercoiled plasmid DNA into linear DNA. The anticancer activity of TNC was tested on four cancer cell lines: MCF7, A549, 4T1 and HepG2. The results indicated that TNC shown significant activity against all of above cell lines.

Efficient oxidation of benzyl alcohol into benzaldehyde catalyzed by graphene oxide and reduced graphene oxide supported bimetallic Au-Sn catalysts.

A series of bimetallic and monometallic catalysts comprising Au and Sn nanoparticles loaded on graphene oxide (GO) and reduced graphene oxide (rGO) were prepared using three distinct techniques: two-step immobilization, co-immobilization, and immobilization. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), energy dispersive X-ray (EDX), and Inductively-coupled plasma optical emission spectroscopy (ICP-OES) were used to characterize the chemical and physical properties of prepared Au-Sn bimetallic and Au or Sn monometallic nanocatalysts. The catalytic performance of the prepared nanocatalysts was evaluated in the selective oxidation of benzyl alcohol (BzOH) to benzaldehyde (BzH) using O2 as an oxidizing agent under moderate conditions. To obtain the optimal BzH yield, the experimental conditions and parameters, including the effects of the reaction time, temperature, pressure, and solvent type on BzOH oxidation, were optimized. Under optimal reaction conditions, bimetallic Au-Sn nanoparticles supported on GO (AuSn/GO-TS, 49.3%) produced a greater yield of BzH than the AuSn/rGO-TS catalysts (35.5%). The Au-Sn bimetallic catalysts were more active than the monometallic catalysts. AuSn/GO-TS and AuSn/rGO-TS prepared by the two-step immobilization method were more active than AuSn/GO-CoIM and AuSn/rGO-CoIM prepared by co-immobilization. In addition, the AuSn/GO-TS and AuSn/rGO-TS catalysts were easily separated from the mixture by centrifugation and reused at least four times without reducing the yield of BzH. These properties make Au-Sn bimetallic nanoparticles supported on GO and rGO particularly attractive for the environmentally friendly synthesis of benzaldehyde.

Hierarchical Co(OH)2 Dendrite Enriched with Oxygen Vacancies for Promoted Electrocatalytic Oxygen Evolution Reaction.

It is critical to develop efficient oxygen evolution reaction (OER) catalysts with high catalytic properties for overall water splitting. Electrocatalysts with enriched vacancies are crucial for enhancing the catalytic activity of OER through defect engineering. We demonstrated the dealloying method in a reducing alkaline solution using the Co5Al95 alloy foil as a precursor to produce a new oxygen-vacancy-rich cobalt hydroxide (OV-Co(OH)2) hierarchical dendrite. The as-synthesised OV-Co(OH)2 showed superior electrocatalytic activities toward OER when compared to pristine cobalt hydroxide (p-Co(OH)2), which had a low onset overpotential of only 242 mV and a small Tafel slope of 64.9 mV dec-1. Additionally, for the high surface area provided by the hierarchical dendrite, both p-Co(OH)2 and OV-Co(OH)2 showed a superior activity as compared to commercial catalysts. Furthermore, they retained good catalytic properties without remarkably decaying at an overpotential of 350 mV for 12 h. The as-made OV-Co(OH)2 has prospective applications as an anode electrocatalyst in electrochemical water-splitting technologies with the advantages of superior OER performances, large surface area and ease of preparation.

MIL-100(Fe) Supported Pt-Co Nanoparticles as Active and Selective Heterogeneous Catalysts for Hydrogenation of 1,3-Butadiene.

Superior catalytic performance for selective 1,3-butadiene (1,3-BD) hydrogenation can usually be achieved with supported bimetallic catalysts. In this work, Pt-Co nanoparticles and Pt nanoparticles supported on metal-organic framework MIL-100(Fe) catalysts (MIL=Materials of Institut Lavoisier, PtCo/MIL-100(Fe) and Pt/MIL-100(Fe)) were synthesized via a simple impregnation reduction method, and their catalytic performance was investigated for the hydrogenation of 1,3-BD. Pt1Co1/MIL-100(Fe) presented better catalytic performance than Pt/MIL-100(Fe), with significantly enhanced total butene selectivity. Moreover, the secondary hydrogenation of butenes was effectively inhibited after doping with Co. The Pt1Co1/MIL-100(Fe) catalyst displayed good stability in the 1,3-BD hydrogenation reaction. No significant catalyst deactivation was observed during 9 h of hydrogenation, but its catalytic activity gradually reduces for the next 17 h. Carbon deposition on Pt1Co1/MIL-100(Fe) is the reason for its deactivation in 1,3-BD hydrogenation reaction. The spent Pt1Co1/MIL-100(Fe) catalyst could be regenerated at 200 °C, and regenerated catalysts displayed the similar 1,3-BD conversion and butene selectivity with fresh catalysts. Moreover, the rate-determining step of this reaction was hydrogen dissociation. The outstanding activity and total butene selectivity of the Pt1Co1/MIL-100(Fe) catalyst illustrate that Pt-Co bimetallic catalysts are an ideal alternative for replacing mono-noble-metal-based catalysts in selective 1,3-BD hydrogenation reactions.

A Water-Stable Zn-MOF Used as Multiresponsive Luminescent Probe for Sensing Fe3+/Cu2+, Trinitrophenol and Colchicine in Aqueous Medium.

A water-stable Zn-MOF was constructed based on H2PBA and 1, 10-phenanthroline under solvothermal conditions. The compound exhibited a 3D (2,3,8)-connected (43)2(46.66.815.12)(8) topology framework. The crystal structure and phase purity of the compound was verified by single crystal X-ray diffraction. Subsequently, some studies on the morphology, structure, and luminescent properties were carried out. The results showed that this compound could be used as a versatile chemosensor for Fe3+/Cu2+, trinitrophenol and colchicine via a luminescence quenching effect in an aqueous medium.

Comparative Study of Pd-Ni Bimetallic Catalysts Supported on UiO-66 and UiO-66-NH2 in Selective 1,3-Butadiene Hydrogenation.

Selective hydrogenation of 1,3-butadiene (BD) is regarded as the most promising route for removing BD from butene streams. Bimetallic Pd-Ni catalysts with changed Pd/Ni molar ratios and monometallic Pd catalysts were synthesized using two differently structured metal-organic framework supports: UiO-66 and UiO-66-NH2. The effects of the structure of support and the molar ratio of Pd/Ni on the catalytic property of selective BD hydrogenation were studied. The Pd-Ni bimetallic supported catalysts, PdNi/UiO-66 (1:1) and PdNi/UiO-66-NH2 (1:1), exhibited fine catalytic property at low temperature. Compared with UiO-66, UiO-66-NH2 with a certain number of alkaline sites could reduce the catalytic activity for the BD hydrogenation reaction. However, the alkaline environment of UiO-66-NH2 is helpful to improve the butene selectivity. PdNi/UiO-66-NH2 (1:1) catalyst presented better stability than PdNi/UiO-66 (1:1) under the reaction conditions, caused by the strong interaction between the -NH2 groups of UiO-66-NH2 and PdNi NPs. Moreover, the PdNi/UiO-66-NH2 (1:1) catalyst presented good reproducibility in the hydrogenation of BD. These findings afford a beneficial guidance for the design and preparation of efficient catalysts for selective BD hydrogenation.

Hexaaqua-magnesium bis-{4-[(5-bromo-2-hy-droxy-benzyl-idene)amino]-benzene-sulfonate} dihydrate.

In the title hydrated mol-ecular salt, [Mg(H(2)O)(6)](C(13)H(9)BrNO(4)S)(2)·2H(2)O, the Mg(2+) ion (site symmetry ) adopts a near regular MgO(6) octa-hedral coordination geometry. In the anion, the dihedral angle between the aromatic rings is 2.5 (2)° and an intra-molecular O-H⋯N hydrogen bond generates an S(6) ring. In the crystal, the components are linked by O-H⋯O and O-H⋯Br hydrogen bonds.

A Multifunctional 3D Supermolecular Co Coordination Polymer With Potential for CO2 Adsorption, Antibacterial Activity, and Selective Sensing of Fe3+/Cr3+ Ions and TNP.

A 3D supermolecular structure [Co3(L)2 (2,2'-bipy)2](DMF)3(H2O)3 1) (H3L = 4,4',4″-nitrilotribenzoic acid) has been constructed based on H3L, and 2,2'-bipy ligands under solvothermal conditions. Compound 1 can be described as a (3, 6)-connected kgd topology with a Schläfli symbol (43)2(46.66.83) formed by [Co3(CO2)6] secondary building units. The adsorption properties of the activated sample 1a has been studied; the result shows that 1a has a high adsorption ability: the CO2 uptakes were 74 cm3·g-1 at 273 K, 50 cm3·g-1 at 298 K, the isosteric heat of adsorption (Qst) is 25.5 kJ mol-1 at zero loading, and the N2 adsorption at 77 K, 1 bar is 307 cm3 g-1. Magnetic measurements showed the existence of an antiferromagnetic exchange interaction in compound 1, besides compound 1 exhibits effective luminescent performance for Fe3+/Cr3+ and TNP.

Aqua-dipyridine-bis-(N-p-tolysulfonyl-l-leucinato)nickel(II).

In each of the two mol-ecules in the asymmetric unit of the title compound, [Ni(C(13)H(18)NO(4)S)(2)(C(5)H(5)N)(2)(H(2)O)], the geometry of the Ni(2+) ion is an extremely distorted trans-NiN(2)O(4) octa-hedron, arising from its coordination by one water mol-ecule, two pyridine mol-ecules, and one O-monodentate and one O,O'-bidentate deprotonated N-p-tolysulfonyl-l-leucine ligand. In the crystal, mol-ecules are linked by N-H⋯O and O-H⋯O hydrogen bonds, forming chains along the c axis. An intra-molecular O-H⋯O hydrogen bond occurs in one of the mol-ecules.

(4-Amino-3-methyl-benzene-sulfonato)tri-µ-aqua-penta-aqua-disodium 4-amino-3-methyl-benzene-sulfonate.

In the title compound, [Na(2)(C(7)H(8)NO(3)S)(H(2)O)(8)](C(7)H(8)NO(3)S), one Na(+) ion is bonded to six water mol-ecules in a distorted octa-hedral arrangement while the other is bonded to five water mol-ecules and one O atom of a 4-amino-3-methyl-benzene-sulfonate anion, also yielding a distorted NaO(6) octa-hedron. Three of the water molecules bridge the metal ions and an intra-molecular O-H⋯O hydrogen bond helps to establish the conformation. In the crystal, the component species inter-act by way of O-H⋯O, O-H⋯N and N-H⋯O hydrogen bonds.

Hexaaqua-magnesium(II) bis-[4-(3-eth-oxy-2-hydroxy-benzyl-ideneamino)-3-methyl-benzene-sulfonate].

In the title compound, [Mg(H(2)O)(6)](C(16)H(16)NO(5)S)(2), the Mg(2+) ion (site symmetry 2) adopts an almost regular octa-hedral coordination geometry. The anion is stabilized by an intra-molecular O-H⋯N hydrogen bond, generating an S(6) ring, and the dihedral angle between the aromatic rings is 41.02 (7)°. In the crystal, the cations and anions are linked by O-H⋯O hydrogen bonds, generating sheets lying parallel to (100).

Two d10 luminescent metal-organic frameworks as dual functional luminescent sensors for (Fe3+,Cu2+) and 2,4,6-trinitrophenol (TNP) with high selectivity and sensitivity.

Two luminescent 3D supramolecular structures [Cd3(L)2(2,2-bipy)2](DMF)3(CH3CH2OH)2(H2O) (1) and [Zn3(L)2(2,2-bipy)2(DMF)2](DMF)2(CH3CH2OH)2(H2O) (2) (H3L = 4,4',4''-nitrilotribenzoic acid) have been successfully synthesized under solvothermal conditions using Cd(NO3)2·4H2O or Zn(NO3)2·6H2O as the metal sources, and 4,4',4''-nitrilotribenzoic acid (H3L), 2,2-bipy as the ligands in DMF solvent. Compound 1 displays a bi-nodal (2,3,6)-coordinated net with {83}2{86·126·163}{8}6 topology, compound 2 can be described as a (3,6)-connected 2-nodal net with kgd topology. The phase purity of compound 1 and 2 is characterized by X-ray powder diffraction (XRPD), thermogravimetric analysis (TGA) and Fourier transform infrared (FT-IR) spectroscopy. Compound 1 and 2 can serve as effective luminescent sensors for Fe3+, Cu2+ and TNP via luminescent quenching.

Bimetallic Au-Pd alloy nanoparticles supported on MIL-101(Cr) as highly efficient catalysts for selective hydrogenation of 1,3-butadiene.

Gold-palladium (Au-Pd) bimetallic nanoparticle (NP) catalysts supported on MIL-101(Cr) with Au : Pd mole ratios ranging from 1 : 3 to 3 : 1 were prepared through coimpregnation and H2 reduction. Au-Pd NPs were homogeneously distributed on the MIL-101(Cr) with mean particle sizes of 5.6 nm. EDS and XPS analyses showed that bimetallic Au-Pd alloys were formed in the Au(2)Pd(1)/MIL-101(Cr). The catalytic performance of the catalysts was explored in the selective 1,3-butadiene hydrogenation at 30-80 °C on a continuous fixed bed flow quartz reactor. The bimetallic Au-Pd alloy particles stabilized by MIL-101(Cr) presented improved catalytic performance. The as-synthesized bimetallic Au(2)Pd(1)/MIL-101(Cr) with 2 : 1 Au : Pd mole ratio showed the best balance between the activity and butene selectivity in the selective 1,3-butadiene hydrogenation. The Au-Pd bimetallic-supported catalysts can be reused in at least three runs. The work affords a reference on the utilization of a MOF and alloy nanoparticles to develop high-efficiency catalysts.