Ai-Guo Zhong

Taizhou College, T’ai-hsien-ch’eng, Jiangsu, China

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Publications (33)

  • [Show abstract] [Hide abstract] ABSTRACT: An organocatalytic Michael reaction of cycloheptanone and cyclooctanone with nitrodienes and nitroolefins catalyzed by a hydroquinine-based primary amine catalyst has been accomplished. The corresponding Michael adducts were obtained in good yields (up to 88%) with good to excellent diastereoselectivities (up to >100:1) and enantioselectivities (up to >99% ee). The absolute configuration of the Michael product was assigned by TDDFT simulation of the ECD spectrum. And the Michael products can be readily converted into analogs of cycloalkano[b] fused pyrrolidines.
    Article · Oct 2014 · New Journal of Chemistry
  • Ai-Guo Zhong
    [Show abstract] [Hide abstract] ABSTRACT: C20H17N5O5Zn, monoclinic, P2(1)/n (no. 14), a = 9.036(2) angstrom, b = 13.917(4) angstrom, c = 15.964(4) angstrom, beta = 100.265(3)degrees, V = 1975.4 angstrom(3), Z = 4, R-gt(F) = 0.0422, wR(ref)(F-2) = 0.0893, T = 296 K.
    Article · Mar 2013 · Zeitschrift für Kristallographie. New crystal structures
  • Ai-Guo Zhong
    [Show abstract] [Hide abstract] ABSTRACT: C12H13N3O4, orthorhombic, Pna2(1) (no. 33), a = 12.8783(6) angstrom, b = 11.3108(6) angstrom, c = 8.6535(4) angstrom, V = 1260.5 angstrom(3), Z = 4, R-gt(F) = 0.0323, wR(ref)(F-2) = 0.0922, T = 296 K. [GRAPHICS] .
    Article · Dec 2012 · Zeitschrift für Kristallographie. New crystal structures
  • Source
    Ai-Guo Zhong
    [Show abstract] [Hide abstract] ABSTRACT: C8H11NO4S2, orthorhombic, Pbca (no. 61), a = 12.003(1) angstrom, b = 9.149(1) angstrom, c = 19.634(2) angstrom, V = 2156.1 angstrom(3), Z = 8, R-gt(F) = 0.044, wR(ref)(F-2) = 0.115, T = 298 K.
    Full-text Article · Jun 2012 · Zeitschrift für Kristallographie. New crystal structures
  • Yan-Xian Jin · Ai-Guo Zhong · Chang-Hua Ge · [...] · Hai-Wan Feng
    [Show abstract] [Hide abstract] ABSTRACT: In order to explore new functional materials, a novel acylhydrazone with isoxazole and furan heterocycles was synthesized and thoroughly investigated by X-ray crystallography, UV and fluorescence spectroscopy, cyclic voltammetry, thermoanalysis, density functional theory (DFT) and time-dependent density functional theory (TDDFT). The molecule has been demonstrated to crystallize in the monoclinic space group P21/c, with the unit cell parameters of (a = 11.3522(19) Å, b = 8.0700(14) Å, c = 12.872(2) Å; α = 90°, β = 106.969(12)°, γ = 90°). In addition, this compound shows characteristic UV absorption peaks at 205, 222 and 308 nm, and fluorescence emission peak at 486.1 nm, which according to our theoretic calculation can all be attributed to (p, π) → π∗ and π → π∗ intraligand charge-transfer transition (ILCT) respectively. According to our cyclic voltammetry result, an oxidation peak of the compound can be observed with onset oxidation potential (Eox) of 0.44 V. Furthermore, the results of antibacterial activities indicate the compound has broad-spectrum against Bacillus subtilis, Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus, which can be supported by the molecular electrostatic potential (MEP). Therefore, this compound exhibits both antibacterial activity and photoluminescent property, namely difunctionality, suggesting that it has potential applications in many fields such as material science and photodynamic therapy.
    Article · Feb 2012 · Journal of Molecular Structure
  • [Show abstract] [Hide abstract] ABSTRACT: Density functional theory calculations have been performed to explore the potential energy surfaces of CO bond activation in CO2 molecule by gas-phase Nb atom and Nb+ cation for better understanding the reaction mechanism of second-row metal with CO2. The minimum-energy reaction path is found to involve the spin inversion in the different reaction steps. This potential energy curve-crossing dramatically affects the reaction energetic. The present results show that the mechanism is insertion-elimination mechanism along the CO bond activation reaction. All theoretical results not only support the existing conclusions inferred from early experiment but also complement the pathway and mechanism for this reaction. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
    Article · Oct 2011 · International Journal of Quantum Chemistry
  • Yan-Xian Jin · Ai-Guo Zhong · Yu-jian Zhang · Fu-You Pan
    [Show abstract] [Hide abstract] ABSTRACT: A novel difunctional acylhydrazone has been synthesized by the reaction of 5-methylisoxazole-4-carboyl hydrazine with benzaldehyde and characterized by X-ray crystallography and spectroscopy. The obtained results demonstrate the crystal belongs to triclinic, space group . Moreover, the spectroscopic properties were evaluated through density functional theory (DFT) and time-dependent density functional theory (TD DFT) calculations. The results reveal that UV–Vis absorption peaks at 194, 217.5 and 290.5 nm are mainly attributed to (p, π) → π∗, partly (p, π) → π∗ and partly π → π∗, and predominantly π → π∗, respectively, with intraligand charge-transfer transition (ILCT) character. The fluorescence emission peak at 485.96 nm should be assigned to ILCT. In addition, the results of antibacterial activities indicate the title compound has certain modest antibacterial activity as well as the broad-spectrum bacteriostasis, which can be supported by the molecular electrostatic potential (MEP). Therefore, the title compound exhibits both antibacterial activity and photoluminescent property, which has potential applications in many fields such as material science and photodynamic therapy.Highlights► A novel acylhydrazone from 5-methylisoxazole-4-carboyl hydrazine and benzaldehyde. ► In this work, both crystalline and molecular structure is determined. ► Fluorescence emission peak at 485.96 nm was assigned to ILCT by TD DFT/HF CIS. ► UV–Vis absorption peaks at 194, 217.5 and 290.5 nm were attributed to ILCT by DFT. ► The title compound has both antibacterial activity and photoluminescent property.
    Article · Sep 2011 · Journal of Molecular Structure
  • Ai-Guo Zhong · Hua-Jiang Jiang · Hua-Ding Liang
    [Show abstract] [Hide abstract] ABSTRACT: We established two good linear relationships between pKa and acidic atom’s electrostatic potential (MEP) in the gas phase by DFT methods at B3LYP/6-31+G(d,p) level of theory. We studied 13 experimentally well-characterized singly substituted benzoic acids to determine the best level of theory. A good linear relationship between MEP and the experimental pKa data has been revealed (standard deviation (STD)=0.081, R2=0.937 for model 1; STD=0.081, R2=0.934 for model 2), better than the computational results in the literatures. Our models also showed that it is reliable to estimate the pKa values of multiply substituted benzoic acids.
    Article · Aug 2011 · Chemical Physics Letters
  • Guo-Liang Dai · Chuan-Feng Wang · Jun-Yong Wu · Ai-Guo Zhong
    [Show abstract] [Hide abstract] ABSTRACT: The reaction mechanism of the Zr atom with CH3CHO has been investigated with a DFT approach. All the stationary points are determined at the UB3LYP/ECP/6-311++G** level of the theory. Both ground and excited state potential energy surfaces are investigated in detail. The present results show that the title reaction start with the formation of a η2-CH3CHO–metal complex followed by CC, aldehyde CH, methyl CH and CO activation. These reactions can lead to six different products (HZrCH3+CO, ZrCO+CH4, ZrCH2CO+H2, ZrCOCH3+H, ZrCH2CHO+H and ZrO+C2H4). The minimum energy reaction path is found to involve the spin inversion in the initial reaction step. This potential energy curve-crossing dramatically affects reaction exothermic. As the triplet intermediates, transition states and products involved in the reaction lie below the ground reactants (Zr(5F)+CH3CHO), the reaction is expected to occur spontaneously over the triplet potential energy surface. The present results may be helpful in understanding the mechanism of the title reaction and further experimental investigation of the reaction.
    Article · Apr 2011 · Computational and Theoretical Chemistry
  • Ai-Guo ZHONG · Ling HUANG · Hua-Jiang JIANG
    [Show abstract] [Hide abstract] ABSTRACT: We investigated eight divalent metal cations M(II) (M=Ca, Mg, Mn, Zn, Cu, Ni, Fe, Co) for the formation of singly H2S-bonded metalated porphyrin-imidazole complexes (L-MP) and H2S bi-bonding of these metalated porphyrin complexes (L-MP*-L, L=H2S, P=porphyrin-imidazole, P*=porphyrin). We investigated their structures, spectroscopic and reactivity properties using density functional theory (DFT), time dependent (TD) DFT, and conceptual DFT approaches using global and local descriptors. Their bonding properties were also analyzed by natural bond orbital (NBO) analysis and by the frontier-electron theory of chemical reactivities. The calculated results reveal that the structures, spectra and reactivities of the L-MP and L-MP*-L complexes are very different from those of their precursor MP. Mg2+ can form stable complexes with porphyrin-imidazole while Ca2+ can not. The ligand L has little influence on the structure of the porphyrin-imidazole. L-MP is more reactive during electrophilic and nucleophilic reactions. UV-Vis spectra showed shifted peaks because of metalation. The iron complex differs from the other metal ion complexes in bonding and reactivity properties such as charge distribution, stability, and nucleophilicity. The transition from the high-spin (S=3) five-coordinate FeP to the lower-spin (S=1) six-coordinate L-FeP leads to a change in the Fukui index (fFe+) of the iron porphyrin. A few quantitative linear relationships were found for the bonding interactions, the charge distributions, and the DFT chemical reactivity indices. In addition, we note that the spin polarization Fukin function plays an important role in metal specificity and reactivity. These results provide in-depth insights into the vascular disorder from endogenous H2S bonded with metal porphyrin complexes.
    Article · Apr 2011 · ACTA PHYSICO-CHIMICA SINICA
  • [Show abstract] [Hide abstract] ABSTRACT: The mechanism of the title reactions have been studied by using the DFT (B3LYP/ECP/6-311+G*) level of theory. Both ground and excited state potential energy surfaces are discussed. It is found the reaction mechanism is insertion mechanism both along the CS and CO bond activation branches, but the CS bond activation is much more favorable in energy than the CO bond activation. The reaction of Y atom with SCO was shown to occur preferentially on the ground state (doublet) PES throughout the reaction process, and the experimentally observed species, have been explained according to the mechanism revealed in this work. Different from that of Y + SCO system, the reaction between Y+ cation and SCO involves potential energy curve-crossing which dramatically affects reaction mechanism. Due to the intersystem crossing existing in the reaction process of Y+ with SCO, the intermediates SY+(η2CO) and OY+(η2CS) may not form. All our theoretical results not only support the existing conclusions inferred from early experiment, but also complement the pathway and mechanism for this reaction. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
    Article · Mar 2011 · International Journal of Quantum Chemistry
  • Source
    Ying Huang · Ai-Guo Zhong · Qinsong Yang · Shubin Liu
    [Show abstract] [Hide abstract] ABSTRACT: The anomeric effect (the tendency of heteroatomic substituents adjacent to a heteroatom within the cyclohexane ring to prefer the axial orientation instead of the sterically less hindered equatorial position) is traditionally explained through either the dipole moment repulsion or the hyperconjugation effect. In this work, by employing our recent work in density functional steric analysis, we provide a novel two-component explanation, which is consistent with the common belief in chemistry that the effect has a stereoelectronic origin. With α-D-glucopyranose as the prototype, we systematically explore its conformational space and generate 32 isomers, leading to a total of 80 axial-equatorial conformation pairs. The energy difference analysis of these pairs shows that while statistically speaking the tendency is valid, the anomeric effect is not always true and can be violated. Three energy components, exchange-correlation, classical electrostatic, and density functional steric, are found to be directly proportional to the total energy difference between axial and equatorial isomers. We also found that the total dipole moment change, not the hyperconjugation effect, is a reasonable indicator of the total energy difference. However, all these correlations alone are not strong enough to provide a compellingly convincing explanation for the general validity of the effect. With the help of strong correlations between energy components, an explanation with two energy components, steric and electrostatic, was proposed in this work. We show that the axial-equatorial energy difference in general, with the anomeric effect as a special case, is dictated by two factors of the stereoelectronic origin, steric hindrance and classical electrostatic interactions, synchronously working together. Another explanation in terms of exchange-correlation and electrostatic interactions has also been obtained in this work.
    Full-text Article · Feb 2011 · The Journal of Chemical Physics
  • Ling Huang · Ai-Guo Zhong · Ding-Ben Chen · [...] · Hua-Ding Liang
    [Show abstract] [Hide abstract] ABSTRACT: Alkaline earth metal complexes of 1,3-bis(carboxymethyl)benzimidazolium (HL) including [Mg(L)2(H2O)4]·2H2O (1), [Ca(L)2(H2O)4]·2H2O (2) and [Ba(L)2(H2O)2·2H2O]n (3) have been synthesized by a hydrothermal procedure and characterized by X-ray crystallography, spectroscopy and thermoanalysis. The results of X-ray crystallography revealed that complexes 1 and 2 are neutral monomers, while complex 3 is a polymeric species, and the carboxymethyl moiety of the deprotonated ligand (L−) acts as a bridge between metal ions. The spectroscopic properties of the complexes were evaluated through density functional theory (DFT) and time-dependent density functional theory (TD DFT) calculations. The results revealed that the absorption peaks in UV–Vis spectra were derived from ligand to ligand charge-transfer transitions (LLCT) and/or (p, π) → (σ∗, π∗) intraligand charge-transfer (ILCT). HL and HL-based complexes displayed similar emission peaks in the near-UV region due to ligand-based LLCT. The results of the Fukui index of the complexes supported LLCT and ILCT mechanisms. In addition, the calculated value of the luminescence oscillator strength displayed a linear relationship with the charge distribution, and the DFT chemical reactivity index, and correlation coefficients (R2) of 0.999 and 0.996 were obtained, respectively. Thus, the results revealed that the emission strength of the complex can be controlled by coordinating the ligand to different metal ions.
    Article · Dec 2010 · Journal of Molecular Structure
  • Guo-Liang Dai · Cuang-Feng Wang · Hao Chen · [...] · Ai-Guo Zhong
    [Show abstract] [Hide abstract] ABSTRACT: Density functional theory (DFT) calculations have been performed to explore the potential energy surfaces of C-O bond activation in CO2 molecule by gas-phase Zr+ cation and Zr atom, for better understanding the mechanism of second-row transition metal reacting with CO2. The minimum energy reaction path is found to involve the spin inversion in the different reaction steps. This potential energy curvecrossing dramatically affects reaction energetics. The present results show that the reaction mechanism is insertion-elimination mechanism along the C-O bond activation. All theoretical results not only support the existing conclusions inferred from early experiment, but also complement the pathway and mechanism for this reaction.
    Article · Dec 2010 · Russian Journal of Physical Chemistry
  • Ai-Guo ZHONG · Ling HUANG · Bai-Ling LI · [...] · Shu-Bin LIU
    [Show abstract] [Hide abstract] ABSTRACT: The tetradentate coordination of bisdipyrrin ligands from cyclooctapyrroles with single and double metal cation metalations generates helical chirality and brings about recent research interests in supremolecular chemistry. In this study, eight divalent metal cations (M(II), M=Ca, Mg, Mn, Zn, Cu, Ni, Fe, Co) in the formation of the singly metalated complexes (1M) and binuclear metal complexes (2M) are systematically investigated to appreciate their structure, spectroscopy, and reactivity properties by using density functional theory (DFT), time-dependent DFT, and conceptual DFT approaches. Their bonding properties are analyzed by the natural bond orbital (NBO) analysis. The simulation results revealed that structure, spectroscopy, and reactivity features of the 1M and 2M complexes are markedly different from their precursor bisdipyrrin (1H) with a larger electrophilicity index, smaller chemical hardness, and distinctive dual descriptor. UV-Vis spectra show diminished peaks with red shifts due to metalation.A few linear structure-reactivity relationships stemmed from these structure and reactivity properties have been obtained with the correlation coefficient (R2) between 0.858 and 0.986. The results can provide in-depth insights for these complexes from structure and reactivity viewpoints.
    Article · Oct 2010 · ACTA PHYSICO-CHIMICA SINICA
  • [Show abstract] [Hide abstract] ABSTRACT: The first highly enantioselective organocatalytic Michael addition of 4-hydroxycoumarins is reported.
    Article · Aug 2010 · ChemInform
  • [Show abstract] [Hide abstract] ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
    Article · Jun 2010 · ChemInform
  • [Show abstract] [Hide abstract] ABSTRACT: Three new oligostilbenes, trans-suffruticosol D (1), cis-suffruticosol D (2), and cis-gnetin H (7), were isolated along with the eight known stilbenes, trans-resveratrol (3), trans-epsilon-viniferin (4), cis-epsilon-viniferin (5), gnetin H (6), suffruticosol A (8), suffruticosol B (9), suffruticosol C (10), and cis-ampelopsin E (11) from the seeds of Paeonia suffruticosa. Compounds 3-6 were isolated for the first time from this plant species, and compound 11 was isolated for the first time from the genus Paeonia. The structures of the new compounds were elucidated based on spectral analyses, including 1D and 2D NMR experiments. The absolute configuration of compound 1 was determined by quantum chemical calculation of the electronic circular dichroism and comparison with the experimental circular dichroism spectrum.
    Article · Jun 2010 · Chemical & pharmaceutical bulletin
  • [Show abstract] [Hide abstract] ABSTRACT: The potential energy surfaces for the La+SCO and La++ SCO reactions have been theoretically investigated by using the DFT (B3LYP/ECP/6-311+G(2d)) level of theory. Both ground and excited state potential energy surfaces (PES) are discussed. The present results show that the reaction mechanism is insertion mechanism both along the C-S and C-O bond activation branches, but the C-S bond activation is much more favorable in energy than the C-O bond activation. The reaction of La atom with SCO was shown to occur preferentially on the ground state (doublet) PES throughout the reaction process, and the experimentally observed species, have been explained according to the mechanisms revealed in this work. While for the reaction between La+ cation with SCO, it involves potential energy curve-crossing which dramatically affects reaction mechanism, and the crossing points (CPs) have been localized by the approach suggested by Yoshizawa et al. Due to the intersystem crossing existing in the reaction process of La+ with SCO, the products SLa+(η2CO) and OLa+(η2CS) may not form. This mechanism is different from that of La + SCO system. All our theoretical results not only support the existing conclusions inferred from early experiment, but also complement the pathway and mechanism for this reaction.
    Article · Jun 2010 · Russian Journal of Physical Chemistry
  • [Show abstract] [Hide abstract] ABSTRACT: (Figure Presented) Distance brings forth beauty: The first highly enantioselective organocatalytic Michael addition of 4-hydroxycoumarins and the analogous 4-hydroxy-6methyl-2-pyrone to β,γ-unsaturated α-keto esters by using chiral squaramides as the organocatalysts is disclosed. The efficiency of the process is attributed to the hydrogen-bonding activation (see scheme).
    Article · Apr 2010 · Chemistry - A European Journal