Synthesis, characterization and crystal structure of 4-methoxybenzylidene-based zinc(II) complexes

Two novel zinc(II) complexes containing 4-methoxybenzylidene moieties namely, Zn(L)Cl2 (L = N, N′-bis(4-methoxybenzylidene)ethane-1, 2-diamine (1) or N-(4-methoxybenzylidene)-ethane-1, 2-diamine (2)) have been synthesized and characterized by infrared spectroscopy and single-crystal X-ray diffraction. Complex 1 crystallizes in the monoclinic space group P21/c with a = 9.2315(4); b = 12.0449(4); c = 18.2164(7) Å; β = 98.472(4)°, V = 1278.9(4) Å3 and Z = 4. Complex 2 crystallizes in the monoclinic space group P21/n with a = 6.5733 (2), b = 13.6595(5), c = 15.1615(5) Å; β = 101.846(4)°, V = 1332.33(8) Å3 and Z = 4. The environment of each Zn(II) atom is distorted tetrahedral with coordination of two terminal Cl atoms and two N atoms of the N,N′ – bis(4-methoxybenzylidene)ethane-1,2-diamine (1) or N-(4-methoxybenzylidene)ethane-1,2-diamine (2) ligand. The stability of the crystalline structure is ensured by the existence of intra- and intermolecular hydrogen bonds of the type C–H…Cl (1) and N–H…Cl (2) leading to supramolecular topologies.

Atmospheric Chemistry of CF3CN: Kinetics and products of reaction with OH radicals, Cl atoms and O3

Long path length FTIR-smog chamber techniques were used to study the title reactions in 700 Torr of N2, oxygen or air diluent at 296 ± 2 K. Values of k(Cl...

Facilely Prepared Cl-Doped Graphene as an Efficient Anode for the Electrochemical Catalytic Degradation of Acetaminophen

The application of electrochemical catalytic oxidation in wastewater treatment with powerful Cldoped graphene as an anode has been discussed as a novel approach to degrade acetaminophen effectively. The characteristics of Cl-doped graphene that were related to Cl loading content and microscopic morphology were analyzed by using several instruments, and the defects created by Cl doping were identified. Quenching experiments and electron paramagnetic resonance detection were proposed to clarify the mechanism underlying the production of active free radicals by Cldopedgraphene. The degradation results indicated that efficiency increased with the percentage of Cl atoms doped into the graphene. The best degradation efficiency of acetaminophen could reach 98% when Cl-GN-12 was used. In the process of electrocatalytic oxidation, O•−2, and active chlorine, as the main active species, persistently attacked acetaminophen into open-ring intermediates, such as 4-chlororesorcinol, and finally into CO2 and H2O.

BSE49, a diverse, high-quality benchmark dataset of separation energies of chemical bonds

We present an extensive and diverse dataset of bond separation energies associated with the homolytic cleavage of covalently bonded molecules (A-B) into their corresponding radical fragments (A. and B.). Our dataset contains two different classifications of model structures referred to as “Existing” (molecules with associated experimental data) and “Hypothetical” (molecules with no associated experimental data). In total, the dataset consists of 4502 datapoints (1969 datapoints from the Existing and 2533 datapoints from the Hypothetical classes). The dataset covers 49 unique X-Y type single bonds (except H-H, H-F, and H-Cl), where X and Y are H, B, C, N, O, F, Si, P, S, and Cl atoms. All the reference data was calculated at the (RO)CBS-QB3 level of theory. The reference bond separation energies are non-relativistic ground-state energy differences and contain no zero-point energy corrections. This new dataset of bond separation energies (BSE49) is presented as a high-quality reference dataset for assessing and developing computational chemistry methods.

trans-Bis[8-(benzylsulfanyl)quinoline-κ2 N,S]dichloridocobalt(II)

The title dichlorocobalt(II) complex, trans-[CoCl2(1)2] [1 = 8-(benzylsulfanyl)quinoline, C16H13NS], has a central CoII atom (site symmetry \overline1) that exhibits a distorted octahedral coordination geometry and is coordinated by two N and two S atoms from the bidentate N,S-ligand (1) situated in an equatorial plane and two Cl atoms in the axial positions. Complexes are linked by weak intermolecular C—H...π interactions between the 8-(benzylsulfanyl)quinoline ligands, forming a chain extending along the a-axis direction.

Atmospheric oxidation of <i>α</i>,<i>β</i>-unsaturated ketones: kinetics and mechanism of the OH radical reaction

The OH-radical-initiated oxidation of 3-methyl-3-penten-2-one and 4-methyl-3-penten-2-one was investigated in two atmospheric simulation chambers at 298±3 K and 990±15 mbar using long-path FTIR spectroscopy. The rate coefficients of the reactions of 3-methyl-3-penten-2-one and 4-methyl-3-penten-2-one with OH radicals were determined to be (6.5±1.2)×10-11 and (8.1±1.3)×10-11 cm3molecule-1s-1, respectively. To enlarge the kinetics data pool the rate coefficients of the target species with Cl atoms were determined to be (2.8±0.4)×10-10 and (3.1±0.4)×10-10 cm3molecule-1s-1, respectively. The mechanistic investigation of the OH-initiated oxidation focuses on the RO2+NO reaction. The quantified products were acetoin, acetaldehyde, biacetyl, CO2 and peroxyacetyl nitrate (PAN) for the reaction of 3-methyl-3-penten-2-one with OH radicals and acetone, methyl glyoxal, 2-hydroxy-2-methylpropanal, CO2 and peroxyacetyl nitrate (PAN) for the reaction of 4-methyl-3-penten-2-one with OH, respectively. Based on the calculated product yields an upper limit of 0.15 was determined for the yield of RONO2 derived from the OH reaction of 4-methyl-3-penten-2-one. By contrast, no RONO2 formation was observed for the OH reaction of 3-methyl-3-penten-2-one. Additionally, a simple model is presented to correct product yields for secondary processes.

N₂O₅ uptake onto saline mineral dust: a potential missing source of tropospheric ClNO₂ in inland China

Nitryl chloride (ClNO2), an important precursor of Cl atoms, significantly affects atmospheric oxidation capacity and O3 formation. However, sources of ClNO2 in inland China have not been fully elucidated. In this work, laboratory experiments were conducted to investigate heterogeneous reaction of N2O5 with eight saline mineral dust samples collected from different regions in China, and substantial formation of ClNO2 was observed. ClNO2 yields, φ(ClNO2), showed large variations (ranging from < 0.05 to ~0.77) for different saline mineral dust samples, largely depending on mass fractions of particulate chloride. In addition, for different saline mineral dust samples, φ(ClNO2) could increase, decrease or show insignificant change as RH increased from 18 % to 75 %. We further found that current parameterizations significantly overestimated φ(ClNO2) for heterogeneous uptake of N2O5 onto saline mineral dust. Assuming a uniform φ(ClNO2) value of 0.10 for N2O5 uptake onto mineral dust, we used a 3-D chemical transport model to assess the impact of this reaction on tropospheric ClNO2 in China, and found that weekly mean nighttime maximum ClNO2 mixing ratios could be increased by up to 85 pptv during a severe dust event in May 2017. Overall, our work showed that heterogeneous reaction of N2O5 with saline mineral dust could be an important source of tropospheric ClNO2 in inland China.

Room-temperature ferroelasticity and unusual sequence of phase transitions in the crystal of (N2H5)3[CdCl5]

On the basis of thermal analysis (DSC, DTA, DTG), single crystal X-ray diffraction experiments, dielectric studies and optical observation, it is found that the (N2H5)3[CdCl5] crystal exhibits several structural phase transitions. At room temperature, the studied crystal exhibits ferroelastic properties and undergoes phase transition from the monoclinic to the orthorhombic phase on heating above 327 K. Upon subsequent cooling, two structural phase transitions at about 323 and 319 K are observed, where the crystal adopts orthorhombic symmetry. The presented phase transitions are unique due to the fact the first heating run results in different structural changes compared to those observed during cooling and subsequent heating/cooling runs. In the studied crystal, N2H5 + ions and 1D chains built up from {CdCl5}3− units bridged by Cl atoms occur. The phase transitions observed can be associated with reorientation of cations and partial disorder of cations as well as Cl atoms.