Iron/cobalt/nickel regulation for efficient photocatalytic carbon dioxide reduction over phthalocyanine covalent organic frameworks.

Using solar photocatalytic CO2 reduction to produce high-value-added products is a promising solution to environmental problems caused by greenhouse gases. Metal phthalocyanine COFs possess a suitable band structure and strong light absorption ability, making them a promising candidate for photocatalytic CO2 reduction. However, the relationship between the electronic structure of these materials and photocatalytic properties, as well as the mechanism of photocatalytic CO2 reduction, is still unclear. Herein, the electronic structure of three MPc-TFPN-COFs (M = Ni, Co, Fe) and the reaction process of CO2 reduction to CO, HCOOH, HCHO and CH3OH were studied using DFT calculations. The calculated results demonstrate that these COFs have a good photo response to visible light and are new potential photocatalytic materials. Three COFs show different reaction mechanisms and selectivity in generating CO2 reduction products. NiPc-TFPN-COFs obtain CO through the reaction pathway of CO2 → COOH → CO, and the energy barrier of the rate-determining step is 2.82 eV. NiPc-TFPN-COFs and FePc-TFPN-COFs generate HCHO through CO2 → COOH → CO → CHO → HCHO, and the energy barrier of the rate step is 2.82 eV and 2.37 eV, respectively. Higher energies are required to produce HCOOH and CH3OH. This work is helping in understanding the mechanism of photocatalytic reduction of CO2 in metallophthalocyanine COFs.

A Drug-Drug Cocrystal of Dihydromyricetin and Pentoxifylline.

Drug-drug cocrystals, which can regulate physicochemical properties of individual drugs and might produce synergistic therapeutic effects, have drawn growing interest in the pharmaceutical industry. In this study, a novel drug-drug (1:1) cocrystal hydrate of slightly water-soluble dihydromyricetin (DMY) and highly water-soluble pentoxifylline (PTX), DMY-PTX•H2O (1), was prepared by a slurry method. The single-crystal X-ray diffraction results reveal that the cocrystal is formed through hydrogen-bonding interactions between hydroxyl groups of DMY and four acceptors of PTX. The dynamic vapour sorption results indicate that the cocrystal displays reduced hydrophilicity compared with DMY. It is found that cocrystal formation narrows the solubility difference between two parent drugs. The equilibrium solubility of PTX decreases greatly, while that of DMY increases slightly. As a result, DMY and PTX are synchronously and sustainedly released from the cocrystal. Further, a synergistic anti-cancer effect of the cocrystal DMY-PTX•H2O (1) on HepG2 cells in vitro at a drug concentration of 100 µM was discovered. This study brings evidence of cocrystallization as a successful approach for synchronous sustained-release of two drugs with substantially different aqueous solubility.

Indirect-to-direct band gap transition and optical properties of metal alloys of Cs2Te1-x Ti x I6: a theoretical study.

In recent years, double perovskites have attracted considerable attention as potential candidates for photovoltaic applications. However, most double perovskites are not suitable for single-junction solar cells due to their large band gaps (over 2.0 eV). In the present study, we have investigated the structural, mechanical, electronic and optical properties of the Cs2Te1-x Ti x I6 solid solutions using first-principles calculations based on density functional theory. These compounds exhibit good structural stability compared to CH3NH3PbI3. The results suggest that Cs2TeI6 is an indirect band gap semiconductor, and it can become a direct band gap semiconductor with the value of 1.09 eV when the doping concentration of Ti4+ is 0.50. Moreover, an ideal direct band gap of 1.31 eV is obtained for Cs2Te0.75Ti0.25I6. The calculated results indicate that all the structures are ductile materials except for Cs2Te0.50Ti0.50I6. Our results also show that these materials possess large absorption coefficients in the visible light region. Our work can provide a route to explore stable, environmentally friendly and high-efficiency light absorbers for use in optoelectronic applications.

Enantioselective permeations of amino acids through L-proline-modified gold nanochannel membrane: an experimental and theoretical study.

L-Proline-modified gold nanochannel membrane (L-Pro-GNM) was prepared and applied for the enantioselective permeations of amino acid enantiomers including tyrosine (Tyr), tryptophan (Trp) and phenylalanine (Phe). Experimental results show that L-Pro-GNM has enantioselectivities for Tyr and Phe enantiomers. Furthermore, the chiral recognition mechanism was studied by density functional theory (DFT) and reduced density gradient (RDG). DFT computational results illustrate that the fundamental chiral recognition system contains two chiral selectors and one selectand, which can be used to evaluate the enantioselective efficiencies of other chiral compounds and the enantioselective ability of other potential amino acid-modified GNM. Finally, graphs obtained by RDG using Multiwfn show helpful visual interactions between the chiral selector and selectand. Results indicate that the electrostatic interaction and hydrogen bonding are responsible for the binding of the chiral selector and selectand, and the larger binding energy shows larger van der Waals interactions.

Preparation of Functionalized Magnetic Fe3O4@Au@polydopamine Nanocomposites and Their Application for Copper(II) Removal.

Polydopamine (PDA) displays many striking properties of naturally occurring melanin in optics, electricity, and biocompatibility. Another valuable feature of polydopamine lies in its chemical structure that incorporates many functional groups such as amine, catechol and imine. In this study, a nanocomposite of magnetic Fe3O4@Au@polydopamine nanopaticles (Fe3O4@Au@ PDA MNPs) was synthesized. Carboxyl functionalized Fe3O4@Au nanoparticles (NPs) were successfully embedded in a layer of PDA through dopamine oxypolymerization in alkaline solution. Through the investigation of adsorption behavior to Cu(II), combined with high sensitive electrochemical detection, the as-prepared magnetic nanocomposites (MNPs) have been successfully applied in the separation and analysis of Cu(II). The experimental parameters of temperature, Cu(II) concentration and pH were optimized. Results showed that the as-prepared MNPs can reach saturation adsorption after adsorbing 2 h in neutral environment. Furthermore, the as-prepared MNPs can be easily regenerated by temperature control and exhibits a good selectivity compared to other metal ions. The prepared Fe3O4@Au@PDA MNPs are expected to act as a kind of adsorbent for Cu(II) deep removal from contaminated waters.

Creating BHb-imprinted magnetic nanoparticles with multiple binding sites.

A kind of protein imprinted over magnetic Fe3O4@Au multifunctional nanoparticles (NPs) with multiple binding sites was synthesized and investigated. Magnetic Fe3O4@Au NPs as carrier materials were modified with 4-mercaptophenylboronic acid (MPBA) and mercaptopropionic acid (MPA) to introduce boronic acids and carboxyl groups. Using Bovine Hemoglobin (BHb) as a template, a polydopamine(PDA)-based molecular imprinted film was fabricated to produce a kind of magnetic molecularly imprinted nanoparticle (MMIP), possessing multiple binding sites with benzene-diol, amino groups, boronic acids and carboxyl groups. The MMIPs exhibited an excellent imprinting effect and adsorption capacity (89.65± 0.38 mg g-1) toward the template protein. The results show that the MMIPs reached saturated adsorption at 0.5 mg mL-1 within 90 min. The synthesized MMIPs are suitable for the removal and enrichment of the template protein in proteomics. The strategy of multiple binding sites paves the way for the preparation of functional nanomaterials in molecular imprinting techniques.

Crystal structure of Brinzolamide: a carbonic anhydrase inhibitor.

In crystal structure of the title compound, C12H21N3O5S3 [systematic name: (R)-4-ethyl-amino-2-(3-meth-oxy-prop-yl)-3,4-di-hydro-2H-thieno[3,2-e][1,2]thia-zine-6-sulfonamide 1,1-dioxide], there exist three kinds of hydrogen-bonding inter-actions. The sulfonamide group is involved in hydrogen bonding with the secondary amine and the meth-oxy O atom, resulting in the formation of layers parallel to the bc plane. The layers are linked by an N-H⋯O hydrogen bond involving a sulfonamide O atom as acceptor and the secondary amine H atom as donor, which gives rise to the formation of a unique bilayer structure. The absolute structure of the mol-ecule in the crystal was determined by resonant scattering [Flack parameter = 0.01 (4)].

Crystal structure of 1,3-dihy-droxy-2-(hy-droxy-meth-yl)propan-2-aminium 2-(4-iso-butyl-phen-yl)propano-ate: a simple organic salt of racemic ibuprofen.

In the title organic salt of ibuprofen with trometamol, C4H12NO3 (+)·C13H17O2 (-), the carb-oxy-lic acid group of ibuprofen has transferred its proton to the amino N atom of trometamol. In the crystal, the trometamol cations are linked via N-H⋯O hydrogen bonds, forming chains along [001]. To these chains are attached the ibuprofen anions via O-H⋯O and N-H⋯O hydrogen bonds. The chains are linked via further N-H⋯O and O-H⋯O hydrogen bonds, forming sheets parallel to (100). Two C atoms of the propano-ate substituent in the ibuprofen anion are disordered over two sets of sites and were refined with a fixed occupancy ratio of 0.7:0.3.

Crystal structure of tetra-aquabis(1,3-dimethyl-2,6-dioxo-3,7-di-hydro-1H-purin-9-ido)magnesium.

The title complex, [Mg(C7H7N4O2)2(H2O)4], lies across an inversion centre and the Mg(II) atom is coordinated in a slightly distorted octa-hedral environment by four aqua ligands in the equatorial sites and two 1,3-dimethyl-2,6-dioxo-3,7-di-hydro-1H-purin-9-ide ligands, through imidazole ring N atoms, in the axial sites. An intra-molecular O-H⋯O hydrogen bond forms an S(7) graph-set motif. In the crystal, O-H⋯O and O-H⋯N hydrogen bonds link complex mol-ecules forming a three-dimensional network incorporating R 4 (2)(8) and R 2 (2)(18) graph-set motifs.

Crystal structure of 7-phenyl-7-(2,4,5-trimethyl-3,6-dioxo-cyclo-hexa-1,4-dien-1-yl)hepta-noate 1,3-dihy-droxy-2-(hy-droxy-meth-yl)propan-2-aminium monohydrate: a new solid form of seratrodast.

In the title hydrated salt, C4H12NO3 (+)·C22H25O4 (-)·H2O, seratrodast [systematic name: 7-phenyl-7-(2,4,5-trimethyl-3,6-dioxo-cyclo-hexa-1,4-dien-1-yl)hepta-noic acid] crystallized with trometamol [systematic name: 2-amino-2-(hydroxyméth-yl)propane-1,3-diol] to form a monohydrated salt form of seratrodast. The carb-oxy-lic acid group of seratrodast has transferred its proton to the amino N atom of trometamol. In the crystal, the trometamol cations are linked to the water mol-ecules and to each other by N-H⋯O and O-H⋯O hydrogen bonds forming sheets parallel to (100). The seratrodast anions are linked to both sides of these sheets by O-H⋯O and C-H⋯O hydrogen bonds, forming a three-layer two-dimensional structure. After forming the title salt, the solubility of seratrodast was found to be greatly improved.

Poly[{µ(3)-3-[4-(1H-imidazol-1-yl-methyl)phen-yl]prop-2-enoato-κN:η:κO}copper(I)].

In the coordination polymer, [Cu(I)(C(13)H(11)N(2)O(2))](n), the Cu(I) atom exists in a trigonal-planar geometry that is defined by the C=C unit, the imidazole N atom and carboxyl-ate O atoms from three different ozagrel ligands, resulting in the formation of a three-dimensional framework.

µ-4,4'-Bipyridine-κN:N'-bis-[aqua-(4,4'-bi-pyridine-κN)(l-valinato-κN,O)copper(II)] dinitrate dihydrate.

In the title dinuclear complex, [Cu(2)(C(5)H(10)NO(2))(2)(C(10)H(8)N(2))(3)(H(2)O)(2)](NO(3))(2)·2H(2)O, each of the two l-valinate anions chelates a Cu(II) center through the amino N and carboxyl-ate O atom, forming a five-membered ring. A 4,4'-bipyridine mol-ecule bridges two water-coordinated Cu atoms, each of which is connected to another 4,4'-bipyridine, giving rise to a square-pyramidal coordination geometry for the Cu(II) centers. The dinuclear dications, nitrate anions and uncoord-inated water mol-ecules are linked into a two-dimensional structure.

2-Methoxy-phenyl 2-{2-[1-methyl-5-(4-methyl-benzo-yl)pyrrol-2-yl]acetamido}acetate.

The title compound, amtolmetin guacil, C(24)H(24)N(2)O(5), is a new gastroprotective non-steroidal anti-inflammatory drug. In the crystal structure, the drug mol-ecule is linked into a one-dimensional structure along the c axis by weak N-H⋯O inter-actions between the amide groups. C-H⋯O and C-H⋯π inter-actions influence the packing.

Hydrogen-bonding interactions in the 4-aminobenzoic acid salt of atenolol monohydrate.

Atenolol {or 4-[2-hydroxy-3-(isopropylamino)propoxy]phenylacetamide} crystallizes with 4-aminobenzoic acid to give the salt {3-[4-(aminocarbonylmethyl)phenoxy]-2-hydroxypropyl}isopropylammonium 4-aminobenzoate monohydrate, C14H23N2O3(+) x C7H6NO2(-) x H2O. In the crystal structure, the water molecule, the carboxylate group of 4-aminobenzoate, and the hydroxy and ether O atoms of atenolol form a supramolecular R3(3) (11) heterosynthon. Three other types of supramolecular synthons link the asymmetric unit into a two-dimensional structure.

Monohydrous dihydrogen phosphate salts of norfloxacin and ciprofloxacin.

Norfloxacin and ciprofloxacin crystallize with phosphoric acid in aqueous solution to give the salts 4-(3-carboxy-1-ethyl-6-fluoro-4-oxo-1,4-dihydro-7-quinolyl)piperazinium dihydrogenphosphate monohydrate, C16H19FN3O3(+) x H2PO4(-) x H2O, and 4-(3-carboxy-1-cyclopropyl-6-fluoro-4-oxo-1,4-dihydro-7-quinolyl)piperazinium dihydrogenphosphate monohydrate, C17H19FN3O3(+) x H2PO4(-) x H2O, respectively. In the crystal structures, the phosphate anions and the piperazine rings of norfloxacin or ciprofloxacin form a 12-membered supramolecular synthon, viz. R4(4)(12). The synthons R4(4)(12) and R2(2)(8) formed between adjacent phosphate anions result in the three-dimensional structures.

4,4'-Bipyridyl N,N'-dioxide-3-hydroxy-2-naphthoic acid (1/2).

4,4'-Bipyridyl N,N'-dioxide crystallizes with 3-hydroxy-2-naphthoic acid to give a centrosymmetric three-component adduct, C(10)H(8)N(2)O(2).2C(11)H(8)O(3), which is engineered into a two-dimensional layer structure by two kinds of pi-pi interactions. Weak C-H...O interactions further link the two-dimensional structure into a three-dimensional structure.

The cocrystal of 3-hydroxy-2-naphthoic acid and 4,4'-bipyridine.

4,4'-Bipyridine cocrystallizes with 3-hydroxy-2-naphthoic acid in a 1:2 ratio to give a centrosymmetric three-component supramolecular adduct, namely 3-hydroxy-2-naphthoic acid-4,4'-bipyridine (2/1), C11H8O3.0.5C10H8N2, in which 4,4'-bipyridine is located on an inversion center. The pyridine-carboxylic acid heterosynthon generates an infinite one-dimensional hydrogen-bonded chain via pi-pi interactions between naphthyl and 4,4'-bipyridine groups. The one-dimensional chains are further assembled into a three-dimensional network by weak C-H...pi interactions between pyridyl and naphthyl rings, and C-H...O interactions between 3-hydroxy-2-naphthoic acid molecules.

Dynamic formation of coordination polymers versus tetragonal prisms and unexpected magnetic superexchange coupling mediated by encapsulated anions in the cobalt(II) 1,3-bis(pyrid-4-ylthio)propan-2-one series.

The reactions of cobalt(II) halides and flexible ligand L [L=1,3-bis(pyrid-4-ylthio)propan-2-one] under different conditions generated a series of complexes with various structural motifs ranging from tetragonal-prismatic cages to 1-3D coordination polymers. The layer diffusion of cobalt(II) chloride and L in methanol/acetone at 25 degrees C gave rise to a 3D polymer, [Co(L)2Cl2].Me2CO. At 30 degrees C, the slow diffusion of diethyl ether into the blue dimethylformamide (DMF) solution of complex 1 afforded a 1D polymer, Co(L)Cl2(DMF)2. However, at 10 degrees C, the diffusion of diethyl ether into the DMF solution of complex 1 produced a tetragonal-prismatic cage, [Co2(L)4Cl2]Cl2.Et2O.DMF.2MeOH.4H2O. The reaction of cobalt(II) bromide and L in DMF at 10 degrees C yielded a dimer, [Co2(L)4Br2]Br2.6DMF.2H2O, with a cage structure similar to. The preparation of the series of compounds indicates the subtle relationship between structures and tunable reaction conditions. It is also found that the structural motifs vary according to the ligand conformations and that the formation of tetragonal-prismatic cages and may be templated by anionic guests. Magnetic studies on complexes in a temperature range 4-300 K disclose that L is unfavorable for a long-range magnetic interaction; however, intramolecular spin-coupling constants of -19.6 and -21.5 cm-1 for and indicate rather strong magnetic superexchanges arising from the overlap of the dz2 orbitals of the cobalt(II) and pz orbitals of the encapsulated halide anions. Electron paramagnetic resonance (EPR) spectra of complexes 3 and 4 in solution and solid give information that both complexes are high-spin cobalt(II) compounds with a rhombic distortion of the axial zero-field splitting. Interestingly, the intramolecular magnetic-exchange coupling in 3 and 4 mediated by the encapsulated anion Cl- or Br- is also reflected by the EPR spectra.

Red luminescent polymeric cuprous organosulfide generated by solvothermal redox reaction.

A new polymeric metal organosulfide [Cu(I)3(pymt)3]n(pymt = pyrimidine-2-thiolate) with strong red photoluminescence was synthesized through solvothermal redox reaction, and crystallographically characterized to be a one-dimensional chiral structure containing metal-metal interactions.