Syntheses and Crystal Structures of Two New Binary Cocrystals of 3-Methyl-4-nitro-pyridine-N-oxide with o-Nitrobenzoic Acid and 3,5-Dinitrosalicylic Acid

Two new binary cocrystals formulated as POM·NBA 1 and POM·DNSA 2 （POM = 3-methyl-4-nitro-pyridine-N-oxide, NBA = o-nitrobenzoic acid, DNSA = 3,5-dinitrosalicylic acid） have been successfully synthesized and characterized by elemental analysis, IR and X-ray single- crystal diffraction analysis. The crystal of 1 crystallizes in triclinic, space group P1, with a = 7.621（4）, b = 7.816（4）, c = 11.702（5） , α = 87.957（10）, β = 83.642（10）, γ = 81.535（10）o, C13H11N3O7, Z = 2, Mr = 321.25, V = 685.1（6） 3, Dc = 1.557 g/cm3, F（000） = 332, μ = 0.129 mm-1, the final R = 0.0632 and wR = 0.0831. The crystal of 2 crystallizes in monoclinic, space group P21/c with a = 14.910（9）, b = 5.904（3）, c =19.321（12） , β = 110.583（10）o, C13H10N4O10, Z = 4, Mr = 382.25, V = 1592.1（16） 3, Dc = 1.595 g/cm3, F（000） = 784, μ = 0.140 mm-1, the final R = 0.0598 and wR = 0.1589. Further structure analysis reveals that the POM with NBA and DNSA molecules in 1 and 2 are linked into 3D structures by the combination of strong O-H…O and weak C-H…O hydrogen bonds, π…π stackings and diverse short contacts, in which different C-H…O weak hydrogen bonds may play a key role in constructing the network structures.

Experimental and Theoretical Studies on the Molecular Structure, FT-IR and UV-vis Spectra of 1,8-Dihydroxyanthraquinone

In the present work, both experimental and theoretical studies have been performed on the molecular structure and infrared spectra of 1,8-dihydroxyanthraquinone （1,8- DHAQ）. The FT-IR spectra （400--4000 cm1） of 1,8-DHAQ were recorded, while density functional B3LYP calculations were employed in conjunction with the 6-31G（d） and 6-311G（d,p） basis sets to investigate the corresponding geometrical structure and infrared spectroscopic properties. Besides, the detailed interpretations of fundamental vibrations were performed on the basis of the experimental results and potential energy distribution （PED） of the vibrational modes. Optimized structure of the title compound was interpreted and compared with the earlier reported experimental values, which yielded good agreement. The measured and calculated harmonic vibrational wavenumbers were compared with each other, and they were found to be in good accordance. Furthermore, UV-vis spectra of the compound were recorded in the region of 215-500 nm, and it was found that the five intense electronic transitions predicted by the EOM-B3LYP/6-31G（d） method were largely consistent with the measured experimental data in the ethanol solution. Moreover, the calculated HOMO and LUMO energies show charge transfer within the molecule.

TD-DFT Study on the Electronic Spectrum Properties of 2,7′-(Ethylene)-bis-8-hydroxyquinoline and Its Derivatives

The structures of 2,7＇-（ethylene）-bis-8-hydroxyquinoline and its derivatives were optimized at the ground states using ab initio HF and B3LYP methods. At the same time, the molecular structures of the first singlet excited state for 2,7＇-（ethylene）-bis-8-hydroxyqulnoline and its derivatives were optimized by CIS/6-31G（d）. The absorption and emission spectra based on the above structures were obtained by the time-dependent density functional theory （TD-DFT） by the B3LYP method with the 6-31G（d） basis set. The calculated results of luminescence originate from the electronic transition from the hydroxphenol ring of 8-hydroxyquinoline A to the pyridine ring of 8-hydroxyquinoline B. Their luminescence wave bands can be tuned by different substituents on the ligand of 8-hydroxyquinoline.

Synthesis and Crystal Structure of One New Adduct of Isonicotinamide and 3,5-Dinitrosalicylic Acid

One new organic adduct,isonicotinamide·3,5-dinitrosalicylic acid with isonico-tin-amide（ina） and 3,5-dinitrosalicylic acid（3,5-dnsa） in 1：1 molar ratio,has been synthesized.Its struc-ture（C13H10N4O8,Mr = 350.25） was characterized by elemental analysis,IR and single-crystal X-ray diffraction analysis.The crystal belongs to the triclinic system,space group P1,with a = 8.812（4）,b = 9.487（5）,c = 9.604（6） ,α = 116.54（2）,β = 97.29（5）,γ = 98.35（4）°,V = 693.8（7） 3,Z = 2,Dc = 1.677 g/cm3,λ（MoKα） = 0.71073 ,μ = 0.142 mm-1,F（000） = 360,the final R = 0.0539 and wR = 0.1402 for 2417 unique reflections（Rint = 0.0288） with 1819 observed ones（Ⅰ 〉 2σ（Ⅰ））.Proton transfer reaction occurs between 3,5-dnsa and ina molecules,and the hydrogen bonds（N-H…O and C-H…O） with other interactions（π…π stacking and weak interactions of O…O and C…O） cooperatively construct a three-dimensional（3D） supramolecular structure.

Maximal Coordinator Number of Potassium, Rubidium, Caesium and Francium Ions in Gaseous Water

To understand the molecular and electronic structure of alkali metal ions, we carry out the MP2 calculation and demonstrate that the maximal coordinator numbers for the hydrated K^＋ and Rb^＋ are 8, while those for the hydrated Cs^＋ and Fr^＋ are 10. Furthermore, on the basis of the binding energy, the HOMO-LUMO gap and the electron affinity, the stability of the molecular and electronic structures of M^＋ （H2O）8 （M= K, Rb, Cs, Fr） decreases with the increasing alkali metal atomic number and the stability of the molecular structures of M^＋ （H20）8-10 （M= Cs, Fr） decreases with the increasing cluster size.

Improvement on the Corrosion Resistance of AZ91D Magnesium Alloy by Aluminum Diffusion Coating

By combination of magnetron sputtering deposition and vacuum annealing, an aluminum diffusion coating was prepared on the substrate of AZ91D alloy to improve its corrosion resistance. The microstructure and composition of the diffusion coating was investigated by scanning electron microscopy and X-ray diffraction. The diffusion coating was mainly comprised of β phase-Al12Mg17. The continuous immersion test in 3.5 wt pct neutral NaCl solution indicated that the specimen with diffusion coating had better corrosion resistance compared with the bare AZ91D alloy specimen. The potentiodynamic polarization measurement indicated that the diffusion coating could function as an effectively protective layer to reduce the corrosion rate of AZ91D alloy when exposed to 3.5 wt pct NaCl solution.

Significantly enhanced oxygen reduction activity of Cu/CuN_xC_y co-decorated ketjenblack catalyst for Al–air batteries

Highly efficient and non-precious catalysts are imperative for oxygen reduction reaction（ORR） to replace Pt/C. Anchoring efficient active species to carbon supports is a promising and scalable strategy. Here we synthesize Cu nanoparticles and noncrystalline CuNxCy species co-decorated ketjenblack（KB） carbon catalyst（denoted as Cu-N-KB-acid） by a facile and scalable method using copper sulfate, melamine, and KB as raw materials. An initial one-pot hydrothermal treatment is designed before pyrolysis process to achieve the good distribution of Cu and melamine on KB via a possible chelation effect. Owing to the synergistic effect of Cu and CuNxCy on KB, this composite catalyst displays excellent ORR catalytic activity in alkaline solution, which is comparable to the commercial 20% Pt/C. When used as a catalyst in a home-made Al-air battery, it shows a stable discharge voltage of 1.47 V at a discharge density of 50 mA cm-2, a little higher than that of Pt/C（1.45 V）.

Preparation of NaYF4:Yb^3+,Tm^3+@NaGdF4:Ce^3+,Eu3+double-jacket microtubes for dual-mode fluorescent anti-counterfeiting

Novel hydrophilic NaYF4:Yb^3+,Tm^3+@NaGdF4:Ce^3+,Eu^3+double-jacket microtubes(DJMTs)with upconversion/downconversion dual-mode luminescence were designed and prepared through epitaxial growth of NaGdF4:Ce^3+,Eu^3+shell onto the NaYF4:Yb^3+,Tm^3+microtube via poly(acrylic acid)(PAA)mediated hydrothermal method.It is demonstrated that PAA ligand played an important role in guiding the direct growth of NaGdF4:Ce^3+,Eu^3+shell onto the surface of NaYF4:Yb^3+,Tm^3+parent microtubes.The growth of NaGdF4:Ce^3+,Eu^3+shell experienced a crystal phase transition fromβ-NaGdF4 andβ-NaYF4 mixture toβ-NaYF4@NaGdF4 composite crystal,and morphology evolution from mixture ofβ-NaGdF4:Ce^3+,Eu^3+nanorods andβ-NaYF4:Yb^3+,Tm^3+microtubes to NaYF4:Yb^3+,Tm^3+@NaGdF4:Ce^3+,Eu^3+DJMTs.The formation mechanism of DJMTs was the dissolution−renucleation ofβ-NaGdF4:Ce^3+,Eu^3+nanorods and the growth ofβ-NaGdF4:Ce^3+,Eu^3+shell via the classical Ostwald ripening mechanism.The as-prepared DJMTs could exhibit blue upconversion and red downconversion luminescence,which was further made into environmentally benign luminescent inks for creating highly secured and fluorescent-based anti-counterfeiting patterns via inkjet printing.

Risk of simulated microgravity on testicular injury induced by high-LET carbon-ion beams in mice

This study investigated the impact of simulated microgravity on acute injury induced by low doses of carbon ions in male reproductive organs of mice,and determined alterations in spermatogenic function and expression levels of apoptotic factors in mice following exposure to acute irradiation after 7 days of simulated microgravity.The results demonstrated that significant reductions in spermatozoa,primary spermatocytes and spermatogonia,and increased globular cells in seminiferous tubule and pro-apoptotic proteins were observed in the group exposed to over0.4 Gy irradiation.Collectively,the data suggest that lesions inflicted by simulated microgravity are not markedly modified by lower doses of irradiation(0.2 Gy)in mouse testis compared to the control group.However,testicular impairments were markedly evident in the group exposed to higher doses of carbon ions plus simulated microgravity,which may be due at least in part to elevated apoptosis initiated by the mitochondrial apoptosis pathway in germ cells.

Theoretical Study on the Excited-state Intramolecular Hydrogen Abstraction Reactions of Butanal

The excited-state intramolecular hydrogen abstraction reactions of butanal have been investigated using the CAS-MP2/6-311＋G^＊//CASSCF/6-31G^＊ methods. Calculated results show that the hydrogen transfer induced fluorescence quenching of the n,π^＊-excited state of covalent butanal with three paths： （1） The first path corresponds to direct S0-react reconstitution, which involves the first S1 decay by partial hydrogen atom transfer. （2） The second stepwise mechanism can be viewed as a full hydrogen atom transfer followed by a partial hydrogen atom back transfer, electron transfer （near S1/S0 or S0-TS） and finally a proton transfer to S0-react. （3） On the triplet surface, the surface crossing to the singlet state would be clearly much efficient at the T1/S0 region due to the large SOC value of 8.3 cm^-1. The S0-react decay route from T1/S0 was studied with an intrinsic reaction coordinate （IRC） calculation at the CASSCF level, resulting in the S0-React minimum.

Theoretical Study on the Mechanism of CF_2 Reaction with CH_2O

The insertion reaction mechanism of CF2 with CH2O was investigated at the B3LYP/6-311G（d）//MP2/6-311G（d） level. The geometric conformations at each stationary point in reaction potential surface were fully optimized and the transition states were verified by intrinsic reaction coordinate （IRC） and frequency analysis. The energies of all reactants were calculated with CCSD（T）/6-311G（d）//G2MP2 methods. Results indicated that the P1 reaction route with difuoroaldehyde as product is the dominant reaction pathway, which exhibits nucleophilic character. According to NBO analysis, the starting point of insertion reaction is the interaction between carbene LP（C3） and formaldehyde π（Cl-O2）. Besides, the thermodynamic and dynamic properties of dominated reaction （1） at different temperature were studied with statistic thermodynamic method and Eyring transition state theory adjusted by Wigner means, from which the proper temperature （500- 1200 K） of reaction （1） could be estimated. Finally, the thermo- dynamic and dynamic properties of insertion reaction mechanisms （CF2, CX2 （X = Cl, Br） with CH2O） were compared and discussed.

Density functional study on chirospectra of hydrogen-bonded systems X^-(H_2O)_3(X=F,Cl,Br,I)

This paper calculates the molecular structures, infrared, Raman, circular dichroism spectra and optical rotatory powers of some hydrogen-bonded supramolecular systems as a cyclic water trimer, （H2O）3 and its pyramidal halide complexes, X- （H2O）3 （X= F, Cl, Br, I） with the gradient-corrected density functional theory method at the B3LYP/6- 311＋＋G（2d,2p） and B3LYP/Aug-cc-pVTZ levels. It finds that the complexation of halide anions with the water trimer can efficiently modulate the chirally optical behaviors. The calculated vibrational circular dichroism spectrum illuminates that the vibrational rotational strength of S（＋） （H2O）3 mostly originates from the O-H rocking modes, whereas chirality of S（-）-X-（H2O）3 （X = F, Cl, Br, I） has its important origin in the O-H stretching modes. The calculated optical rotatory power demonstrates that S（＋） （H2O）3 and S（＋）-F-（H2O）3 are positively chiral, whereas S（-）-X-（H2O）3 （X=Cl, Br, I） are negatively chiral. With the polarizable continuum model, calculated bulk solvent effect in the solvents water and carbontetrachloride and argon shows that the positive chirality of S（＋）-（H2O）3 is enhanced and the negative chirality of S（-）-X-（H2O）3 （X=Cl, Br, I） and the positive chirality of S（＋）-F-（H2O）3 are reduced with an augmentation of the solvent dielectric constant.

Deposition of Pd on Co(OH)_(2) nanoplates in stabilizer-free aqueous phase for catalytic reduction of 4-nitrophenol

Palladium-supported cobalt hydroxide(Co(OH)_(2)-Pd) nanoplates were fabricated in an aqueous solution and employed as a catalyst for the reduction of 4-nitrophenol.For the preparation of Co(OH)2-Pd,Pd nanoparticles were anchored on the Co(OH)_(2) nanoplates after the reduction of Na;PdCl;by ascorbic acid in the absence of a stabilizer at room temperature.The observations under transmission and scanning electron microscopy reveal that Pd nanoparticles with a size of 2-5 nm are uniformly dispersed on the surface of the Co(OH)_(2) nanoplates.In catalytic test,the conversion of 4-nitrophenol to 4-aminophenol is completed within 6 min in the presence of Co(OH)_(2)-Pd(1000) nanoplates with2.18 at.% Pd,and the corresponding kinetic constant is 0.0089 s;in the first test.The catalyst retains relatively high activity after several cycles.The results demonstrate that the Co(OH)_(2)-Pd(1000) nanoplates exhibit high catalytic activity toward the reduction of 4-nitrophenol in the presence of NaBH;.

A New ent-Kaurane Diterpenoid from Isodon enanderianus

A new spirosecokaurenoid, enanderinanin F 1 and its C-6 epimer, angustifolin were isolated from the aerial parts of Isodon enanderianus. The structure of 1 was determined on the basis of spectral data, especially by 2D techniques. The C-13 NMR data of angustifolin were revised by 2D NMR.

Robust,self-adhesive,and low-contact impedance polyvinyl alcohol/polyacrylamide dual-network hydrogel semidry electrode for biopotential signal acquisition

Herein,we fabricated a flexible semidry electrode with excellent mechanical performance,satisfactory self-adhesiveness,and low-contact impedance using physical/chemical crosslinked polyvinyl alcohol/polyacrylamide dual-network hydrogels(PVA/PAM DNHs)as an efficient saline reservoir.The resultant PVA/PAM DNHs showed admirable adhesive and compliance to the hairy scalp,facilitating the establishment of a robust electrode/skin interface for biopotential signal transmission.Moreover,the PVA/PAM DNHs steadily released trace saline onto the scalp to achieve the minimized potential drift(1.47±0.39 mV/min)and low electrode–scalp impedance(18.2±8.9 kΩ@10 Hz).More importantly,the application feasibility of real-world brain−computer interfaces(BCIs)was preliminarily validated by 10 participants using two classic BCI paradigms.The mean temporal cross-correlation coefficients between the semidry and wet electrodes in the eyes open/closed and the N200 speller paradigms are 0.919±0.054 and 0.912±0.050,respectively.Both electrodes demonstrate anticipated neuroelectrophysiological responses with similar patterns.This semidry electrode could also effectively capture robust P-QRS-T peaks during electrocardiogram recording.Considering their outstanding advantages of fast setup,user-friendliness,and robust signals,the proposed PVA/PAM DNH-based electrode is a promising alternative to wet electrodes in biopotential signal acquisition.

Crown ether-appended Fe(Ⅲ) porphyrin:Synthesis,characterization and catalytic oxidation of cyclohexene with molecular oxygen

A new crown ether appended Fe（Ⅲ） porphyrin complex was prepared by sulfuryl chloride appended benzo-15-crown-5 to the meso position of meso-5,10,15,20-tetra（4-hydrophenyl）porphyrin,and it was applied to catalytic oxidation of cyclohexene with molecular oxygen without reductant,showing a remarkable catalytic activity（conversion is up to 94%） and selectivity for 2-cyclohexen-1-ol（73%）.

Salicylic acid promotes quiescent center cell division through ROS accumulation and down-regulation of PLT1,PLT2,and WOX5

Salicylic acid(SA)plays a crucial role in plant immunity.However,its function in plant development is poorly understood.The quiescent center(QC),which maintains columella stem cells(CSCs)in the root apical meristem and typically exhibits low levels of cell division,is critical for root growth and development.Here,we show that the Arabidopsis thaliana SA overaccumulation mutant constitutively activated cell death 1(cad1),which exhibits increased cell division in the QC,is rescued by additional mutations in genes encoding the SA biosynthetic enzyme SALICYLIC ACID INDUCTION DEFFICIENT2(SID2)or the SA receptor NONEXPRESSER OF PR GENES1(NPR1),indicating that QC cell division in the cad1 mutant is promoted by the NPR1-dependent SA signaling pathway.The application of exogenous SA also promoted QC cell division in wild-type plants in a dose-dependent manner and largely suppressed the expression of genes involved in QC maintenance,including those encoding the APETALA2(AP2)transcription factors PLETHORA1(PLT1)and PLT2,as well as the homeodomain transcription factor WUSCHEL-RELATED HOMEOBOX5(WOX5).Moreover,we showed that SA promotes reactive oxygen species(ROS)production,which is necessary for the QC cell division phenotype in the cad1 mutant.These results provide insight into the function of SA in QC maintenance.

Two New Iridoid Glucosides from Clerodendrum serratum

Two new iridoid glucosides, serratoside A and serratoside B, were isolated from the aerial parts of Clerodendrum serratum var. amplexifolium Moldenke. Their structures were elucidated by spectral and chemical methods.

Spin-orbit coupling and zero-field splitting of the high-spin ferric enzyme-substrate complex:Protocatechuate 3,4-dioxygenase complexed with 3,4-dihydroxyphenylacetate

We used density functional calculations to investigate the electronic origins of the magnetic properties of the high-spin ferric enzyme-substrate complex protocatechuate 3,4-dioxygenase(3,4-PCD).The calculated g-tensors show that ligand-to-metal charge transfer transitions are from the protocatechuate(PCA) and Tyr408 orbitals to the Fe d orbitals,which lead to x-and y-polarized transitions.These polarized transitions require a spin-orbit coupling(SOC) matrix element in the z-direction,Lz(z=z'),resulting in a g z value of 2.0158,significantly deviating from 2.0023.A large zero-field splitting parameter value of+1.147cm-1 is due to △S =-1 spin-orbit mixing with the quartet states for the sextet ground state,accounting for around 73% of the SOC contribution.The SOC matrix elements indicate that the high-spin d 5 system Fe(Ⅲ),3,4-PCD-PCA is a weak spin-crossover compound with an SOC of 31.56 cm-1.