Enhancement in Sensitivity and Selectivity of Electrochemical Technique with CuO/g-CN Nanocomposite Combined with Molecularly Imprinted Polymer for Melamine Detection.

This study focused on enhancing the sensitivity and selectivity to detect melamine by utilizing a photoelectrochemical method. This was achieved by combining a melamine-imprinted polymer with a CuO/g-CN nanocomposite, which was synthesized through chemical precipitation and calcination. The resulting nanocomposite exhibits improved carrier mobility and photoelectrochemical properties.

Stability improvement of UV-filter between methoxy cinnamic acid derivatives and cyclodextrins inclusion complexes based on DFT and TD-DFT investigations.

Structures and UV-vis absorption spectra of the host-guest interaction of the methoxy cinnamic acid (MCA) derivatives and cyclodextrins (CDs) were performed by using the density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations. All geometries of MCA derivatives (4-MCA, 245-MCA, 246-MCA), three types of CD (αCD, βCD, γCD), and five host-guest inclusion complexes between MCA and CD consisting of 4-MCA/αCD (1), 4-MCA/βCD (2), 245-MCA/βCD (3), 246-MCA/βCD (4), and 246-MCA/γCD (5) were fully optimized by using the M06-2X/6-31G (d,p) levels of theory. Two orientations (A and B) of the MCA guest molecule were considered.

Defect-Engineered Hydroxylated Mesoporous Spinel Oxides as Bifunctional Electrocatalysts for Oxygen Reduction and Evolution Reactions.

In this work, defect-rich ordered mesoporous spinel oxides, including CoCoO, NiCoO, and ZnCoO, were developed as bifunctional electrocatalysts toward oxygen reduction and evolution reactions (ORR and OER, respectively). The materials are synthesized via nanocasting and modified by chemical treatment with 0.1 M NaBH solution to enhance the defect concentration.

Stepwise Access of Emissive Ir(III) Complexes Bearing a Multi-Dentate Heteroaromatic Chelate: Fundamentals and Applications.

Three multi-dentate coordinated chelates LH ( = 1, 2, and 3), comprising a linked 1-(pyridin-2-yl)ethylbenzene and one pyrazolyl pyridine unit and showing either tridentate or tetradentate coordination modes, are successfully designed and synthesized. Dinuclear Ir(III) complexes [Ir(κ-L)(μ-Cl)] bearing tetradentate coordinated κ-L chelate (, = 1; , = 2; , = 3) were next obtained en route from the respective intermediate [Ir(κ-LH)Cl(μ-Cl)] bearing the tridentate coordinated κ-LH chelate (, = 1; , = 2; , = 3). Next, mononuclear Ir(III) complexes Ir(-L)(thd) (, = 1; , = 2; , = 3) with the tetradentate chelate were obtained upon treatment of with 2,2,6,6-tetramethyl-3,5-heptanedione (thd)H in the presence of KCO.

Crystal structure, Hirshfeld surface analysis and computational study of a rhodamine B-salicyl-aldehyde Schiff base derivative.

The mol-ecular structure of the title compound {systematic name: 3',6'-bis(di-ethyl-amino)-2-[(2-hy-droxy-benzyl-idene)amino]-spiro-[isoindoline-1,9'-xan-then]-3-one}, CHNO or RbSa, can be seen as being composed of two parts sharing a central quaternary carbon atom. Both the xanthene and iso-indole moieties are nearly planar: 14 atoms in the former moiety show an r.m.

Crystal structure, Hirshfeld surface analysis and computational study of 2-chloro--[4-(methyl-sulfan-yl)phen-yl]acetamide.

In the title compound, CHClNOS, the amide functional group -C(=O)NH- adopts a conformation with the four atoms nearly coplanar. This conformation promotes the formation of a (4) hydrogen-bonded chain propagating along the [010] direction. The central part of the mol-ecule, including the six-membered ring, the S and N atoms, is fairly planar (r.

5-Methyl-1,3-phenyl-ene bis-[5-(di-methyl-amino)-naphthalene-1-sulfonate]: crystal structure and DFT calculations.

The title compound, CHNSO, possesses crystallographically imposed twofold symmetry with the two C atoms of the central benzene ring and the C atom of its methyl substituent lying on the twofold rotation axis. The two dansyl groups are twisted away from the plane of methyl-phenyl bridging unit in opposite directions. The three-dimensional arrangement in the crystal is mainly stabilized by weak hydrogen bonds between the sulfonyl oxygen atoms and the hydrogen atoms from the -methyl groups.

Photophysical properties for excited-state intramolecular proton transfer (ESIPT) reaction of N-salicylidene-o-aminophenol: Experimental and DFT based approaches.

Photophysical properties for excited-state intramolecular proton transfer (ESIPT) reaction of N-salicylidene-o-aminophenol (SA) Schiff base were comprehensively studied based on experimental methods combined with theoretical calculations. The results revealed that the SA was mainly presented in enol form in acidic solutions while it was predominantly existed in keto form in basic solutions. From UV-vis absorption and fluorescence emission studies, it showed that the ESIPT could effectively take place in non-polar and aprotic polar solvents.

Density functional theory study of adsorption geometries and electronic structures of azo-dye-based molecules on anatase TiO surface for dye-sensitized solar cell applications.

Structural and electronic properties of eight isolated azo dyes (ArNNAr', where Ar and Ar' denote the aryl groups containing benzene and naphthalene skeletons, respectively) were investigated by density functional theory (DFT) based on the B3LYP/6-31G(d,p) and TD-B3LYP/6-311G(d,p) methods The effect of methanol solvent on the structural and electronic properties of the azo dyes was elucidated by employing a polarizable continuum model (PCM). Then, the azo dyes adsorbed onto the anatase TiO (101) slab surface through a carboxyl group. The geometries and electronic structures of the adsorption complexes were determined using periodic DFT based on the PWC/DNP method.

Bis(phenothiazyl-ethynylene)-Based Organic Dyes Containing Di-Anchoring Groups with Efficiency Comparable to N719 for Dye-Sensitized Solar Cells.

A new series of acetylene-bridged phenothiazine-based di-anchoring dyes have been synthesized, fully characterized, and used as the photoactive layer for the fabrication of conventional dye-sensitized solar cells (DSSCs). Tuning of their photophysical and electrochemical properties using different π-conjugated aromatic rings as the central bridges has been demonstrated. This molecular design strategy successfully inhibits the undesirable charge recombination and prolongs the electron lifetime significantly to improve the power conversion efficiency (η), which was proven by the detailed studies of electrochemical impedance spectroscopy (EIS) and open-circuit voltage decay (OCVD).

Elucidation of hydroxyl groups-antioxidant relationship in mono- and dihydroxyflavones based on O-H bond dissociation enthalpies.

Radical scavenging potential is the key to anti-oxidation of hydroxyflavones which generally found in fruits and vegetables. The objective of this work was to investigate the influence of hydroxyl group on the O-H bond dissociation enthalpies (BDE) from a series of mono- and dihydroxyflavones. Calculation at the B3LYP/6-31G(d,p) level reveals the important roles of an additional one hydroxyl group to boost the BDE of hydroxyflavones that were a stabilization of the generated radicals through attractive H-bond interactions, an ortho- and para-dihydroxyl effect, and a presence of the 3-OH in dihydroxyflavones.

Photophysical properties and photochemistry of substituted cinnamates and cinnamic acids for UVB blocking: effect of hydroxy, nitro, and fluoro substitutions at ortho, meta, and para positions.

Photophysical properties and photochemistry of various substituted cinnamates and cinnamic acids for ultraviolet B blocking were investigated experimentally and theoretically. This series includes monohydroxy, -nitro, and -fluoro derivatives. The absorption spectra were satisfactorily reproduced by the direct SAC-CI method with respect to the peak position and intensity.

The effect of alkali and Ce(III) ions on the response properties of benzoxazine supramolecules prepared via molecular assembly.

A series of benzoxazine monomer supramolecules with different substituted groups on their benzene ring was prepared with a Mannich reaction and characterized by FTIR, 1H-NMR and MS. The obtained products were 3,4-dihydro-3-(2'-hydroxyethylene)-6-methyl-2H-benzoxazine (BM1), 3,4-dihydro-3-(2'-hydroxyethylene)-6-ethyl-2H-benz-oxazine (BM2), and 3,4-dihydro-3-(2'-hydroxyethylene)-6-methoxy-2H-benzoxazine (BM3). The efficiency of alkali metal ion extraction from the products was determined with Pedersen's technique, while the complexation of the Ce(III) ion was confirmed by the Job's and the mole ratio methods.

Photophysical properties and photochemistry of EE-, EZ-, and ZZ-1,4-dimethoxy-2,5-bis[2-(thien-2-yl)ethenyl] benzene in solution: theory and experiment.

Photophysical properties and photoisomerization of 1,4-dimethoxy-2,5-bis[2-(thien-2-yl)ethenyl] benzene (DMTB) have been investigated for the EE-, EZ-, and ZZ- stereoisomers. The EE-DMTB was prepared, and the absorption/fluorescence spectra of EE- isomer as well as transient spectra in photoisomerization among three isomers were observed. Absorption and fluorescence spectra of three isomers were analyzed by the symmetry-adapted cluster-configuration interaction (SAC-CI) and time-dependent density functional theory (TDDFT) methods.

Novel recovery of nano-structured ceria (CeO(2)) from Ce(III)-benzoxazine dimer complexes via thermal decomposition.

N,N-bis(2-hydroxybenzyl)alkylamines, benzoxazine dimers, are the major product produced from benzoxazine monomers on mono-functional phenol by the one step ring opening reaction. Due to the metal responsive property of benzoxazine dimers, in this present work, N,N-bis(5-methyl-2-hydroxybenzyl)methylamine (MMD), N,N-bis (5-ethyl-2-hydroxybenzyl)methylamine (EMD), and N,N-bis(5-methoxy-2-hydroxybenzyl) methyl amine (MeMD), are considered as novel ligands for rare earth metal ion, such as cerium(III) ion. The complex formed when the clear and colorless solutions of cerium nitrate and benzoxazine dimers were mixed, results in a brown colored solution.

Absorption and emission spectra of ultraviolet B blocking methoxy substituted cinnamates investigated using the symmetry-adapted cluster configuration interaction method.

The absorption and emission spectra of ultraviolet B (UVB) blocking cinnamate derivatives with five different substituted positions were investigated using the symmetry-adapted cluster configuration interaction (SAC-CI) method. This series included cis- and trans-isomers of ortho-, meta-, and para-monomethoxy substituted compounds and 2,4,5-(ortho-, meta-, para-) and 2,4,6-(ortho-, para-) trimethoxy substituted compounds. The ground and excited state geometries were obtained at the B3LYP/6-311G(d) and CIS/D95(d) levels of theory.