Boosting activity of γ-alumina-supported vanadium catalyst for isobutane non-oxidative dehydrogenation via pure V.

The vanadium-based dehydrogenation (DH) catalyst is becoming a promise alternative to the industrial used Pt- and Cr-based catalysts, due to lower cost and less environmental threat. However, the low DH activity hampered the industrial application of vanadium-based catalysts. Herein, for the first time, we introduce a method to prepare high-efficiency vanadium-based catalyst by constructing pure V species on γ-AlO through treatment of as-prepared thiovanadate.

Boryl Radical-Promoted Dehydroxylative Alkylation of 3-Hydroxyoxindole Derivatives.

A boryl radical-promoted dehydroxylative alkylation of 3-hydroxy-oxindole derivatives is achieved. The reaction starts from addition of 4-dimethylaminopyridine (DMAP)-boryl radical to the amide carbonyl oxygen atom, which induces a spin-center shift process to promote the C-O bond cleavage. The elimination of a hydroxide anion from a free hydroxy group is also accomplished.

Lewis Base-Boryl Radicals Enabled Borylation Reactions and Selective Activation of Carbon-Heteroatom Bonds.

ConspectusThe past decades have witnessed tremendous progress on radical reactions. However, in comparison with carbon, nitrogen, oxygen, and other main group element centered radicals, the synthetic chemistry of boron centered radicals was less studied, mainly due to the high electron-deficiency and instability of such 3-center-5-electron species. In the 1980s, Roberts and co-workers found that the coordination of a Lewis base (amines or phosphines) with the boron center could form 4-center-7-electron boryl radicals (Lewis base-boryl radicals, LBRs) that are found to be more stable.

Novel two-photon absorption compounds with different organic cations: facile synthesis, photophysical properties, detection of viscosity, and selective imaging of the endoplasmic reticulum in living cells.

Three novel imidazole-based two-photon absorption compounds bearing different organic cations (1PIPy, 2PIQu, and 3PIIm) were facilely synthesized and fully characterized by H NMR, C NMR, FT-IR, and HRMS. The linear and nonlinear photophysical properties of the target compounds were systematically investigated in various solvents, supplemented with the density functional theory calculations to shed light on their structure-property relationships. The maximum two-photon action cross-sections ( × ) were determined to be 22.

Novel red light-emitting two-photon absorption compounds with large Stokes shifts for living cell imaging.

Three novel donor-π-acceptor two-photon absorption compounds (1PZPy, 2PZIm, 3CZPy) bearing the 10-butyl-10H-phenothiazine (9-butyl-9H-carbazole) donor, the pyridinium (benzimidazolium) acceptor, and the 2,5-divinylthiophene π-bridge were synthesized and fully characterized by H NMR, C NMR, FT-IR, and HRMS. The linear and nonlinear photophysical properties were systematically investigated. Their absorption properties show a strong solvent dependence, while the emission properties are nearly independent of solvent polarity.

Dehydroxylative Alkylation of α-Hydroxy Carboxylic Acid Derivatives via a Spin-Center Shift.

A strategically distinct dehydroxylative alkylation reaction of α-hydroxy carboxylic acid derivatives with alkenes is developed. The reaction starts with the attack of a 4-dimethylaminopyridine (DMAP)-boryl radical to the carbonyl oxygen atom, followed by a spin-center shift (SCS) to trigger the C-O bond scission. The resulting α-carbonyl radicals couple with a wide range of alkenes to furnish various alkylated products.

[Relationship between Blood Glucose and Lipid Levels and Intestinal in Middle-Aged and Older Adults in Chengdu].

Objective: To explore characteristics of the species structure of the genus at different levels of blood glucose and lipid in middle-aged and older adults in Chengdu so as to provide research basis for applying bifidobacteria in the prevention and treatment of hyperglycemia and dyslipidemia.

Methods: A total of 289 middle-aged and older adults of 45 and older were recruited in Chengdu between April and August 2018. They were divided into the healthy group, the dyslipidemia group, the hyperglycemia group, and the combination group (of subjects with both dyslipidemia and hyperglycemia).

Isobutane dehydrogenation over high-performanced sulfide V-K/γ-AlO catalyst: Modulation of vanadium species and intrinsic effect of potassium.

Compared with industrial used Pt- and Cr-based catalyst in dehydrogenation (DH) of light alkanes, the sulfide V-K/γ-AlO catalyst reported in this study shows lower cost and toxicity, and significant DH performance. The yield to isobutene reached as high as 52.9%, which is among the highest reported to date.

Sequential C-F bond functionalizations of trifluoroacetamides and acetates via spin-center shifts.

Defluorinative functionalization of readily accessible trifluoromethyl groups constitutes an economical route to partially fluorinated molecules. However, the controllable replacement of one or two fluorine atoms while maintaining high chemoselectivity remains a formidable challenge. Here we describe a general strategy for sequential carbon-fluorine (C-F) bond functionalizations of trifluoroacetamides and trifluoroacetates.

An "Umpolung Relay" Strategy: One-Pot, Twice Polarity Inversion Cascade Synthesis of Diversified [60]Fulleroindoles.

An "umpolung relay" strategy, which includes an one-pot, twice polarity inversion cascade of C via carbanion and carbocation polarity reversed relay pathway, has been developed for the synthesis of a diverse range of novel [60]fulleroindole derivatives.

A novel flurophore-cyano-carboxylic-Ag microhybrid: Enhanced two photon absorption for two-photon photothermal therapy of HeLa cancer cells by targeting mitochondria.

In this study, a novel two-photon photothermal therapy (TP-PTT) agent based on an organic-metal microhybrid with surface Plasmon resonance (SPR) enhanced two-photon absorption (TPA) characteristic was designed and synthesized using a fluorescent cyano-carboxylic derivative 2-cyano-3-(9-ethyl-9H-carbazol-3-yl) -acrylic acid (abbreviated as CECZA) and silver nanoparticles through self-assembly process induced by the interfacial coordination interactions between the O/N atom of CECZA and Agion at the surface of Ag nanoparticles. The coordination interactions caused electron transfer from the Ag nanoparticles to CECZA molecules at the excited state, resulting in a decreased fluorescence quantum yield. The interfacial coordination interactions also enhanced the nonlinear optical properties, including 13 times increase in the TPA cross-section (δ).

A specific HeLa cell-labelled and lysosome-targeted upconversion fluorescent probe: PEG-modified SrYbF:Tm .

In this study, water-soluble PEG-modified SrYbF:Tm was prepared conveniently by a one-pot solvothermal method, where the molar ratio of Sr to Yb was controlled between 3 : 2 and 1 : 1. The optimum red-light emission at 677-699 nm was modulated via 0.7% Tm doped under irradiation at 980 nm.

Coordination coupling enhanced two-photon absorption of a ZnS-based microhybrid for two-photon microscopy imaging in HepG2.

Coordination coupling induced self-assembly of ZnS microparticles was performed with the help of a π-conjugated sulphur-terminal Zn(ii) complex ZnSL (L = N-hexyl-3-{2-[4-2,2':6',2''-terpyridin-4'-yl-phenyl]ethenyl}-carbazole). The interactions between ZnS and ZnSL components at the interface, which were analyzed by far-IR and XPS, resulted in a tunable single-photon excited fluorescence and an enhanced nonlinear optical response, including a two-photon absorption cross section and a two-photon excited fluorescence. Such an enhancement in nonlinear optical properties was triggered by the coordination coupling effect between terminal S atoms of ZnSL and naked Zn ions at the surface of ZnS particles.

Crystal structure of poly[di-chlorido-(μ-2,5-di-carb-oxy-benzene-1,4-di-carboxyl-ato-κ:)bis-[μ-4'-(pyridin-3-yl)-4,2':6',4''-terpyridine-κ:]dizinc].

In the title polymeric Zn complex, [Zn(CHO)Cl(CHN)] , the Zn cations are bridged by both 2,5-di-carb-oxy-benzene-1,4-di-carboxyl-ate dianions and 4'-(pyridin-3-yl)-4,2':6',4''-terpyridine ligands, forming ladder-like polymeric chains propagating along [1-10]. The Cl anion further coordinates the Zn cation to complete a distorted tetra-hedral environment. In the 4'-(pyridin-3-yl)-4,2':6',4''-terpyridine ligand, the three sideward pyridine rings are twisted with respect to the central pyridine ring by 39.

A new series of two-photon blue/violet fluorescent trans-alkenes: Green synthesis and optical properties.

A new series of trans-alkenes (3a-3e) containing different electron-donating groups were synthesized by the solvent-free Horner-Wadsworth-Emmons reaction, and characterized by infrared, hydrogen nuclear magnetic resonance, mass spectrometry and elemental analysis. Their UV-visible absorption, one-photon excited fluorescence, two-photon absorption, and two-photon excited fluorescence were systematically investigated in different solvents. Experimental results show different trends in linear and nonlinear optical properties with different donor units.

A zinc(II) metal-organic framework with a novel topology formed from 4,4',4''-nitrilotribenzoate and 4,4'-bipyridine ligands.

A metal-organic framework with a novel topology, poly[sesqui(μ2-4,4'-bipyridine)bis(dimethylformamide)bis(μ4-4,4',4''-nitrilotribenzoato)trizinc(II)], [Zn3(C21H12NO6)2(C10H8N2)1.5(C3H7NO)2]n, was obtained by the solvothermal method using 4,4',4''-nitrilotribenzoic acid and 4,4'-bipyridine (bipy). The structure, determined by single-crystal X-ray diffraction analysis, possesses three kinds of crystallographically independent Zn(II) cations, as well as binuclear Zn2(COO)4(bipy)2 paddle-wheel clusters, and can be reduced to a novel topology of a (3,3,6)-connected 3-nodal net, with the Schläfli symbol {5.

2-((E)-{4-[Bis(4-eth-oxy-phen-yl)amino]-phen-yl}imino-meth-yl)phenol.

In the title Schiff base mol-ecule, C29H28N2O3, the three terminal benzene rings are twisted by 73.84 (15), 81.25 (16) and 12.

Poly[tetrachlorido{μ4-tetrakis[(imidazol-1-yl)methyl]methane-κ4N3:N3':N3'':N3'''}dizinc(II)] exhibiting a three-dimensional diamond topology.

The title novel noncentrosymmetric metal-organic framework, [Zn2Cl4(C17H20N8)]n, was prepared solvothermally using the tetradentate tetrakis[(imidazol-1-yl)methyl]methane (tiym) linker in the presence of zinc nitrate under acidic conditions. The asymmetric unit contains one Zn(II) cation, two Cl(-) anions and a quarter of each of two symmetry-independent tiym ligands. Each Zn(II) cation is four-coordinated by two Cl(-) anions and two imidazole N atoms from two tiym ligands, forming a distorted tetrahedral coordination geometry.

A tetranuclear organotin compound consisting of a core of three fused Sn2O2 rings.

The crystal structure of the tetranuclear organotin compound 1,1,3,3,5,5,7,7-octabutyl-7-((E)-2-cyano-3-{9-[2-(2-methoxyethoxy)ethyl]-9H-carbazol-3-yl}prop-2-enoyloxy)-4,8-dimethyl-2,4,6,8-tetroxa-1,3,5,7-tetrastannatricyclo[4.2.0.

Synthesis, characterization, cytotoxicity and antibacterial activity of an anthracenyl-linked bis(pyrazolyl)methane ligand and its zinc(II) complexes.

Three novel Zn(II) complexes (1-3) with 1,1'-(anthracen-9-ylmethylene)bis(1H-pyrazole) (L(2)) have been prepared and structurally characterized by X-ray crystallography. Among them, 1 is a binuclear Zn(II) complex while 2 and 3 are mononuclear. The in vitro cytotoxic and antibacterial activities of these complexes were also evaluated.

A self-assembled nanohybrid composed of fluorophore-phenylamine nanorods and Ag nanocrystals: energy transfer, wavelength shift of fluorescence and TPEF applications for live-cell imaging.

A fluorophore-phenylamine derivative (L) has been coupled with silver nanocrystals (NCs) to construct an L-Ag nanohybrid. Owing to synergic effects of the L and Ag components, the exciton-plasmon interactions between L and Ag increase the strength of the donor-acceptor interaction within the nanohybrid, a fact that results in an energy-transfer process and further brings about a dramatic redshift of single-photon absorption and fluorescence, and a decreased fluorescence FL lifetime. The coupling effect also leads to enhancement of a series of nonlinear optical properties, including two-photon-excited fluorescence (TPEF), two-photon-absorption (TPA) cross section (δ), two-photon-absorption coefficient (β), nonlinear refractive index (γ), and third order nonlinear optical susceptibility (χ((3))).

Silver(I) supramolecular complexes generated from isophorone-based ligands: crystal structures and enhanced nonlinear optical properties through metal complexation.

By self-assembly of (E)-2-(3-(4-(1H-imidazol-1-yl)styryl)-5,5-dimethylcyclohex-2-enylidene)malononitrile (L(1)) and (E)-2-(3-(4-(1H-1,2,4-triazol-1-yl)styryl)-5,5-dimethylcyclohex-2-enylidene)malononitrile (L(2)) with silver(I) salts, eight new complexes, namely AgL(1)2ClO4 (1), AgL(1)2NO3 (2), [AgL(1)2NO3]·C6H6 (3), [AgL(1)2OOCCF3]·C6H6 (4), [AgL(1)2PF6]·C6H6 (5), AgL(2)2NO3 (6), [AgL(2)OOCCF3]2 (7) and AgL(2)2PF6 (8), are presented along with an analysis of their structural features. The structures are built up through the combination of coordination bonds, Ag···π, Ag···F (or O), hydrogen bonding, and π···π stacking interactions to generate new supramolecular architectures. We observed the formation of two-dimensional coordination polymers for complex 7.

N,N-Diethyl-4-[1-phenyl-3-(pyridin-2-yl)-4,5-di-hydro-1H-pyrazol-5-yl]aniline.

In the title mol-ecule, C24H26N4, the pyrazoline ring assumes an envelope conformation with the aniline-bearing C atom at the flap position. The benzene ring and the pyridine ring form with the pyrazoline ring dihedral angles of 4.53 (1) and 6.

{9-Hexyl-2-[2-phenyl-6-(pyridin-2-yl)pyridin-4-yl]-9H-carbazole}di-iodido-zinc.

In the title compound, [ZnI2(C34H31N3)], the Zn(II) atom is four-coordinated by two I atoms and the pyridine N atoms from the bidentate 6'-phenyl-2,2'-bi-pyridine ligand in a distorted tetra-hedral geometry.