Insights into the photocatalysis mechanism of the novel 2D/3D Z-Scheme g-C3N4/SnS2 heterojunction photocatalysts with excellent photocatalytic performances.

A novel 2D/3D Z-scheme g-C3N4/SnS2 photocatalyst was successfully fabricated via self-assembly forming 3D flower-like SnS2 microspheres on the surface of the 2D g-C3N4 nanosheets. The photocatalytic performances of the samples were systematically explored through catalytic reduction of Cr6+ and oxidation of Bisphenol S (BPS) under the illumination of visible light, and the photocatalytic degradation pathway of BPS was also proposed based on the degradation products confirmed by GCMS. Among the as-prepared samples, 0.4-g-C3N4/SnS2 exhibited the most efficient photocatalytic performances, and the apparent quantum efficiency (QE) for the removal of Cr6+ could achieve 30.3 %, which is 2.8 times higher than that of the SnS2. The enhancing photocatalytic activities originated from the efficient interfacial charge migration and separation obtained in g-C3N4/SnS2, which was firstly verified via the photoluminescence spectra, time-resolved photoluminescence spectra and photoelectrochemical characterizations. Importantly, the DFT calculated shows that the band distribution of the g-C3N4/SnS2 sample is staggered near the forbidden, which can facilitate the efficient interfacial charge migration and separation as well as result in the improvement of the catalytic activity. Finally, we put forward a more reasonable Z-scheme charge transfer mechanism, it was verified by analysing the results of free radical scavenging tests, EPR experiments and theoretical calculations.

Influence of pyrolysis temperature on the properties and environmental safety of heavy metals in chicken manure-derived biochars.

Animal manures usually contain high contents of heavy metals (HMs) and thus pose a considerable threat to human health and environment when applied to soil. In this study, the effect of pyrolysis temperature (300 °C, 400 °C, 500 °C, 600 °C, and 700 °C) on the properties of biochar produced from chicken manure was studied. In addition, the response of speciation, bioavailability, leachability, and environmental risk of HMs in biochar to different pyrolysis temperature was investigated. The results showed that biochars pyrolyzed at high temperatures generally had high pH, ash content, surface area, and stability. As the pyrolysis temperature increased, the total concentrations of Cu, Zn, Cr, and Ni continually increased, whereas those of Pb and Cd initially increased and then decreased. Moreover, the transformation of the bioavailable fractions of HMs into stable fractions obviously increased with increasing pyrolysis temperature. Thus, pyrolysis at high temperature led to a further decrease in the bioavailability, leachability, and environmental risk of six HMs, as shown by DTPA, TCLP, and the potential ecological risk index. Overall, it is convincing that that 700 °C is the optimal temperature when considering the quality and environmental safety of biochar derived from chicken manure.

Influence of sodium hydroxide addition on characteristics and environmental risk of heavy metals in biochars derived from swine manure.

In order to improve characteristics of biochar, especially enhance immobilization of heavy metals in biochar, swine manure was pyrolyzed at low pyrolysis temperature (300 °C, 400 °C and 500 °C) with different amounts of sodium hydroxide (NaOH) added (0.5% and 2%, W/W). Results showed that NaOH addition during pyrolysis increased the pH, EC, ash content, yield rate, aromaticity and hydrophily, but did not increase surface area and porosity of resultant biochars. The addition of NaOH promoted the transformation of the mobile fraction of Cu, Zn and Cd into the oxidizable fraction. With respect to Cr and Pb, the oxidizable and residual fractions were increased slightly by the presence of NaOH. Meanwhile, adding NaOH could reduce the leachability and ecological risks of heavy metals in biochars. Our study suggested that NaOH-assisted pyrolysis of swine manure was an effective disposal approach for the immobilization of heavy metals.

Structural, spectral and magnetic studies of two Co(II)-N-heterocyclic diphosphonates based on multinuclear units.

Two examples of Co(II)-N-heterocyclic coordination polymers based on 1-hydroxyethylidenediphosphonic acid (H5L=CH3C(OH)(PO3H2)2), namely 0.5(H3NCH2CH2NH3)·[Co6(Cl2)(H3L)2(H2L)(HL)(2,2'-bipy)6] 1 and 2(NH4)·[Co3(HL)2(H2O)2(phen)2]·2(H2O) 2, have been solvothermally obtained by introducing the second ligands 2,2'-bipyridine/1,10-phenanthroline (2,2'-bipy/phen) and characterized by powder X-ray diffraction (PXRD), elemental analysis, IR, TG-DSC. The single-crystal X-ray diffractions show that compound 1 possesses a 0-D structure with hexa-nuclear cluster [Co6(O-P-O)8] built through single/double O-P-O bridges and compound 2 displays a 1-D ladder-like chain structure with magnetic topology building blocks [Co4(O-P-O)4]n. Then H-bonding and π-π stacking interactions further expand the two low-dimensional structures into three-dimensional supramolecular frameworks. Fluorescent measurements reveal that both the maximum emission peaks of 1-2 are centered at 423nm, mainly deriving from intraligand π*-π transition state of N-heterocyclic ligand 2,2'-bipy/phen, respectively. Magnetism data indicate that 1 exhibits antiferromagnetic behavior within hexa-nuclear Co(II) clusters, while 2 shows weak ferromagnetic interactions in 1-D topology Co(II)-chain, showing promising potential as magnetic materials.

Synthesis, structural characterization and theoretical approach of the tri(2-(2,6-dichlorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline) cobalt(II).

The crystal structure of a new coordination compound tri(2-(2,6-dichlorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline) Co(II) complex ([Co(dcpip)3]Cl2) was measured with X-ray diffraction measurements. The compound is crystallizes triclinic, Pi space group. The ligand, 2-(2,6-dichlorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline(dcpip), binds to Co(II) ions with a bis-dentate mode, and each Co(II) ion with a distorted octahedral coordination geometry. The calculated interaction energies of Co(II) with coordination atoms N are between 101.7-206.5 kJ/mol and 115.3-230.9 kJ/mol for B3LYP/6-31+G(∗) and PBE1PBE/6-31+G(∗) theoretical methods, respectively. The experimental Fourier transform infrared spectrum was assigned. The calculated IR based on B3LYP/6-31+G(∗) and PBE1PBE/6-31+G(∗) methods were performed and compared with experimental results. The UV-Vis experimental spectrum of [Co(dcpip)3]Cl2 was measured in methanol solution. The calculated electronic spectrum was performed with TD/B3LYP and TD/PBE1PBE methods with 6-31+G(∗) basis set. The first and second order hyperpolarizability for the compound was calculated. The calculated values of γtot are -1.5551344 × 10(-33) esu for B3LYP method and -1.3323259 × 10(-33) esu for PBE1PBE method. The nature bond orbital analysis and temperature dependence of the thermodynamic properties were calculated with the same methods.

Experimental and DFT studies on the vibrational and electronic spectra of 9-p-tolyl-9H-carbazole-3-carbaldehyde.

The compound 9-p-tolyl-9H-carbazole-3-carbaldehyde (HCCD) was synthesized and characterized by X-ray diffraction, FT-IR, FT-Raman and UV-Vis spectra. The X-ray diffraction study showed that HCCD has a Z-configuration. The benzene ring including methyl is twisted from the mean plane of the carbazole group by 59.7(3)°, which is comparable with the calculated result 65° for B3LYP/6-311++G(d, p) method. Vibrational spectra and electronic spectra measurements were made for the compound. Optimized geometrical structure and harmonic vibrational frequencies were computed with B-based DFT (BLYP, B3LYP and cam-B3LYP) methods, and WB-based DFT (WB97, WB97X and WB97XD) methods and ab initio RHF method using 6-311++G(d, p) basis set. Assignments of the observed spectra were proposed. The equilibrium geometries computed by all of the methods were compared with X-ray diffraction results. The absorption spectra of the title compound were computed both in gas phase and in DMF solution using TD-(cam)B3LYP/6-311++G(d, p) and PCM-(cam)B3LYP/6-311++G(d, p) approaches, respectively. The calculated results provide good descriptions of the bands maxima in the observed electronic spectrum. Temperature dependence of thermodynamic parameters in the range of 100-1000 K was determined. The natural atomic hybrids were calculated and discussed.

Experimental and DFT studies on the vibrational and electronic spectra and NBO analysis of 2-amino-3-((E)-(9-p-tolyl-9H-carbazol-3-yl) methyleneamino) maleonitrile.

2-Amino-3-((E)-(9-p-tolyl-9H-carbazol-3-yl) methyleneamino) maleonitrile (ACMM) was synthesized and characterized by X-ray diffraction, FT-IR, FT-Raman and UV-Vis spectra. The X-ray diffraction study showed that ACMM has a Z-configuration, due to the intramolecular C18H18A⋯N2, N3H3A⋯N2 and C20H20A⋯N4 hydrogen bonds and intermolecular C10H10A⋯N4, N3H3B⋯N9 (2-x, 2-y, 2-z) and N3H8C⋯N4 (2-x, 1-y, 2-z) hydrogen bonds. The benzene ring including methyl is twisted from the mean plane of the carbazole group by 59.7(3)°. Vibrational spectra and electronic spectra measurements were made for the compound. Optimized geometrical structure and harmonic vibrational frequencies were computed with DFT (B3-based B3P86, B3LYP, B3PW91 and B-based BP86, BLYP, BPW91) methods and ab initio RHF method using 6-311++G(d, p) basis set. Assignments of the observed spectra were proposed. The equilibrium geometries computed by all of the methods were compared with X-ray diffraction results. The absorption spectra of the title compound were computed both in gas phase and in DMF solution using TD-B3LYP/6-311++G(d, p) and PCM-B3LYP/6-311++G(d, p) approaches, respectively. The calculated results provide a good description of positions of the bands maxima in the observed electronic spectrum. Temperature dependence of thermodynamic parameters in the range of 100-1000K were determined. The bond orbital occupancies, contribution from parent natural bond orbital (NBO), the natural atomic hybrids was calculated and discussed.

Experimental and DFT studies on the vibrational, electronic spectra and NBO analysis of thiamethoxam.

Vibrational and electronic spectral measurements were performed for 3-(2-chloro-1,3-thiazol-5-ylmethyl)-5-methyl-1,3,5-oxadiazinan-4-ylidene(nitro) amine (thiamethoxam). Optimized geometrical structure and harmonic vibrational frequencies were calculated with ab initio RHF and DFT (B3LYP, CAMB3LYP, M06 and PBE1PBE) methods with 6-311++G (d, p) basis set. Complete assignments of the observed spectra were proposed. The absorption spectra of the compound were computed in gas-phase using TD-B3LYP/6-311++G (d, p) approach and H2O solution using PCM-TD-B3LYP/6-311++G (d, p) approach. The calculated results matched well with the experimental values. Temperature dependence of thermodynamic parameters in the range of 100-1000 K were determined. The bond orbital occupancies, contribution from parent natural bond orbital (NBO), the natural atomic hybrids was discussed.

Two novel Cu(II) diphosphonates: structural, spectral and magnetic studies.

By introducing the second organic N-heterocyclic ligands 2,2'-bipyridine (2,2'-bipy)/1,10-phenanthroline (phen), two mono-/bi-nuclear examples of Cu(II)-diphosphonate coordination polymers based on 1-hydroxyethylidenediphosphonic acid (H5L=CH3C(OH)(PO3H2)2), [Cu(H4L)2(2,2'-bipy)]·H2O 1 and [Cu(H3L)(phen)]2·(HOCH2CH2OH)0.52, have been solvothermally obtained and characterized by powder X-ray diffraction, elemental analysis, IR, TG-DSC. The single-crystal X-ray diffractions show that both the two compounds possess zero-dimensional structures, built from mononuclear unit [CuO4N2]n for 1 and binuclear unit [-Cu-O-P-O-]2n with a double O-P-O bridge for 2 in syn-anti fashion. Then H-bond or/and π-π interactions further expand the two zero-dimensional structures into the three-dimensional supramolecular frameworks. Fluorescent measurements reveal that the maximum emission peaks of 1-2 centered at 433.5nm for 1 and 434.5nm for 2, respectively, are mainly caused by intraligand π(*)-π emission state of N-heterocyclic ligands (λex=235nm). The further magnetic study shows the two coordination polymers exhibit antiferromagnetic behavior for 1 between the mononuclear units, while ferromagnetic behavior for 2 derived from double O-P-O bridges in syn-anti mode between the metal centers.

Experimental and DFT studies on the vibrational and electronic spectra of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone.

Vibrational and electronic spectral measurements were made for 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). Optimized geometrical structure and harmonic vibrational frequencies were computed by DFT(B3LYP, CAMB3LYP, B3P86, M062X, mPW3PBE and PBE1PBE) using 6-311++G(d,p) basis set. Complete assignments of the observed spectra were proposed. The absorption spectra of the compound were computed both in gas-phase and in CH(2)Cl(2) solution using TDCAMB3LYP/6-311++G(d,p) and PCM-TDCAMB3LYP/6-311++G(d,p) approaches, respectively, the calculated results provide a good description of positions of the bands maxima in the observed electronic spectrum.

Facile synthesis and photo-physical properties of cyano-substituted styryl derivatives based on carbazole/phenothiazine.

Four new cyano-substituted styryl derivatives based on carbazole and phenothiazine were facilely synthesized by conventional Knoevenagel condensation and well characterized. The UV-vis spectra of these dyes showed the lowest-energy absorption bands were mainly caused by the HOMO-LUMO one-electron promotion as conformed by TD-DFT calculations. The thermogravimetric analysis showed these dyes were thermally stable up to 350 °C. The UV-vis absorption and fluorescence emission spectra were also studied in solvents of different polarity, these dyes exhibited unusual large Stokes shift.

catena-[[(nitrato-κO)silver(I)]-µ-1,10-phenanthroline-5,6-dione-κO,O':N,N'].

In the title one-dimensional coordination polymer, [Ag(NO(3))(C(12)H(6)N(2)O(2))](n), the Ag(I) atom is penta-coordinated by two N atoms from a 1,10-phenanthroline-5,6-dione (phen-dione) ligand, one O atom from the nitrate anion and two O atoms from another phen-dione ligand. The coordination environment around silver is slightly distorted square-pyramidal. Inter-estingly, the Ag-O distances to the phen-dione ligand are different [Ag-O = 2.612 (6) and 2.470 (5) Å]. The one-dimensional chains run parallel to [101] and are further inter-connected by weak hydrogen bonds (C-H⋯O) and π-π stacking inter-actions [centroid-centroid distances 3.950 (4) and 3.792 (4) Å], forming a three-dimensional supra-molecular network.

N-heterocyclic amine-directed structures and properties of two Cu(II) diphosphonates.

By introducing the second organic N-heterocyclic ligands 4'-(4-pyridyl)-4,2':6',4''-terpyridine (pyterpy) and 4,4'-bipyridyl (4,4'-bipy), two examples of Cu(II)-diphosphonates, [Cu(3)(HL)(2)(Hpyterpy)(2)]·2H(2)O 1 and [Cu(4)(HL)(2)(4,4'-bipy)(H(2)O)(5)] 2 based on 1-hydroxyethylidenediphosphonic acid (H(5)L = CH(3)C(OH)(PO(3)H(2))(2)), have been hydrothermally obtained and characterized by powder X-ray diffraction, elemental analysis, IR, TG-DSC. The single-crystal X-ray diffractions reveal that compound 1 has a one-dimensional fishbone-like chain constructed by anions [Cu(3)(HL)(2)(2-)](n) while simultaneously organic cations [Hpyterpy(+)](n) suspending both sides, and compound 2 exhibits two-dimensional inorganic-organic alternate arrangement layer built from 1-D ladder-like inorganic chain with tetranuclear cluster [Cu(4)O(10)] via 4,4'-bipy linkage. The results of electrochemical measurements indicate half-wave potential of 1 (E(1/2)(1) = 1.01 V) is less than that of 2 (E(1/2)(2) = 1.20 V), indicating a good D-A system in ICT for 1. Moreover fluorescent measurements reveal that emission intensity of 1 centered at 422 nm is larger than that of 2 emitted at 420 nm, caused by intraligand π*-π emission state of organic N-heterocyclic amine (λ(ex) = 233 nm). Magnetism data indicate that compound 1 exhibits ferrimagnetic interactions between metal centers, while compound 2 has antiferromagnetic property.

[Resolution of the epinephrine enantiomers derivatized with fluorescent chiral reagent by reversed-phase high performance liquid chromatography].

A new method was developed to separate epinephrine enantiomers derivatized with fluorescent chiral reagent, R-(-)/S-(+)-4-(N, N-dimethylaminosulfonyl)-7-(3-iso-thiocyanatopyrrolidino)-2, 1, 3-benzoxadiazole (DBD-PyNCS), by reversed-phase high performance liquid chromatography, on a Diamonsil C18 column(150 mm x 4.6 mm i.d., 5 microns), with a mobile phase of water-acetonitrile(72:28, volume ratio) and a fluorescent detector at the excitation wavelength of 460 nm and the emission wavelength of 550 nm. The column was eluted at 40 degrees C, with a flow rate of 1 mL/min. At first, let the fluorescent chiral reagent(36 mmol/L, 10 microL) react with epinephrine enantiomers(1 mmol/L, 10 microL), and then 10 microL 20% pyridine acetonitrile solution was added. The resulting mixture was stirred for 1 min and kept at 65 degrees C for 35 min and then a 10 microL aqueous of the diastereomeric derivatives was injected directly into the chromatograph. The diastereomeric compounds were efficiently separated. The Rs value was 2.6 with alpha of 1.07. The k's of L-epinephrine and D-epinephrine were 17.11 and 18.13 respectively. The retention times of L-epinephrine and D-epinephrine were 30.24 min and 31.94 min respectively. The linear range was 0.07 g/L -0.50 g/L (r = 0.9995). The RSD was 4.3%(n = 7). The detection limit was 12 g/L(S/N = 3).