2-巯基苯并咪唑及其类似物互变异构的理论研究

采用B3LYP/6-311G**方法, 计算了2-巯基苯并咪唑及其类似物(2-巯基苯并噁唑、2-巯基苯并噻唑、2-羟基苯并咪唑、2-羟基苯并噁唑、2-羟基苯并噻唑以及2-巯基咪唑、2-巯基噁唑、2-巯基噻唑、2-羟基咪唑、2-羟基噁唑、2-羟基噻唑)的(硫)醇式与(硫)酮式结构进行质子迁移的3种可能途径: (a)分子内质子迁移; (b)水助质子迁移; (c)甲醇助质子迁移．结果表明, 途经b和c所需要的活化能较小, 氢键在降低反应活化能方面起重要作用．采用PCM方法研究了反应体系的溶剂化效应．结果表明孤立分子、一水合物和一甲醇合物的最稳定异构体相同, 都为(硫)酮式, 与气相结论一致．溶剂化效应对异构化能垒的影响较小.     

Concise syntheses of 2-aminoindans via indan-2-ol

2-Amino-5,6-dimethoxyindan hydrochloride was synthesized in seven steps and with an overall yield of 48%. Indan-2-ol was converted to 5,6-dibromo-indan-2-ol in three steps by acetylation, electrophilic bromination and deacetylation. Dimethoxylation of 5,6-dibromoindan-2-ol with NaOCH₃ in the presence of CuI gave 5,6-dimethoxy-indan-2-ol, which was converted to 2-amino-5,6-dimethoxyindan hydrochloride by azidation, followed by Pd-C catalyzed hydrogenation. Similarly, 2-amino-5-bromoindan was synthesized in five steps and with an overall yield of 50%. Indan-2-ol was converted to 2-aminoindan by azidation followed by Pd-C catalyzed hydrogenation. The reaction of 2-aminoindan with 2.5 equiv Br₂ afforded 2-amino-5,6-dibromoindan.     

Reaction of Grignard Compounds with 4-Chloro-2-methyl-3-butyn-2-ol in Diethyl Ether Equivalents

Reactions of RMgX·THF complexes with 4-chloro-2-methyl-3-butyn-2-ol in aromatic hydrocarbons were studied. The complexes formed by arylmagnesium halides require the presence of anisole for the reaction to occur. 4-Chloro-2-methyl-3-butyn-2-ol can be synthesized by reaction of 2-methyl-3-butyn-2-ol with sodium hypochloride in the two-phase system water-benzene.     

精氨酸侧链和核酸碱基间离子氢键作用强度分析

采用MP2/6-31+G(d,p)方法优化得到了22个由精氨酸侧链与碱基尿嘧啶、 胸腺嘧啶、 胞嘧啶、 鸟嘌呤及腺嘌呤形成的氢键复合物的气相稳定结构, 使用包含BSSE校正的MP2/aug-cc-pVTZ方法计算得到了复合物的气相结合能, 通过MP2/6-31+G(d,p)方法和PCM模型优化得到了复合物的水相稳定结构, 采用MP2/aug-cc-pVTZ方法和PCM模型计算得到了复合物的水相结合能. 研究发现, 精氨酸侧链与碱基间的离子氢键作用强度与单体间电荷转移量、 氢键临界点电子密度及二阶作用稳定化能密切相关. 与中性氢键相比, 离子氢键作用具有更显著的共价作用成分. 研究还发现, 精氨酸侧链和碱基间形成的氢键复合物的稳定性次序可以通过氢键受体碱基分子上氧原子和氮原子的质子化反应焓变进行预测, 质子化反应焓变越负, 形成的氢键复合物越稳定.     

Theoretical Investigations on the Interaction Nature of Br2 with HF, H2O and NH3

The interactions of HF, H2O and NH3 with Br2 are investigated at the MP2(full)/ aug-cc-pVDZ level. It is found that two kinds of stable complexes, halogen-bonded and hydrogen- bonded complexes, exist between Br2 and HF and between Br2 and H2O. The interaction energy analysis and natural population analysis (NPA) are conducted to these two kinds of complexes, indicating the halogen-bonded complexes are more stable than the corresponding hydrogen-bonded ones, and the binding energies of the former increase in the order HFH2O for the latter.     

Molecular self-assembling of chiral and racemic butan-2-ol in carbon tetrachloride solutions

The self-association of (R)-, (S)- and (RS)-butan-2-ol in their carbon tetrachloride solutions was studied through the mid-infrared (mid-IR) and near-infrared (NIR) spectroscopic observations. The mid-IR and NIR spectra for each chiral butan-2-ol were compared with those for the racemic (RS)-butan-2-ol. Although it has been reported that the hydrogen bonding among the chiral butan-2-ol molecules was stronger than that among the racemic ones, any distinguishable differences between the chiral and the racemic butan-2-ol in CCl₄ solution or even in their pure liquid state were not observed both in their mid-IR and NIR spectra. A superior analytical method, assuming a successive association process for the alcohol molecules, was applied to the analysis of the sharp band at 3630 cm⁻¹ (the OH-stretching vibration mode attributed to free OH-monomer) for the (R)-, (S)- or (RS)-butan-2-ol in CCl₄. The mean association number N for each alcohol increased with increasing in concentration until 0.12 mol dm⁻³ and then becomes constant (about four). On the other hand, Zanker's plotting method, assuming an equilibrium between monomers and only one kind of polymer species, was also applied to the analysis of the above spectroscopic results; the association number n evaluated from the Zanker's method fairly agreed with the N value in the concentration region of 0.12–0.60 mol dm⁻³.     

Robust hydrogen-bonded self-assemblies from biimidazole complexes. Synthesis and structural characterization of [M(biimidazole)2(OH2)2]2+ (M = Co2+, Ni2+) complexes and carboxylate modules

A robust heteromeric hydrogen-bonded synthon [R2(2) (9)-Id] is exploited to drive the modular self-assembly of four coordination complexes [M(H2biim)2(OH2)2]2+ (M = Co2+, Ni2+) and carboxylate counterions. This strategy allowed us to build molecular architectures of 0-, 1-, and 2-dimensions. A hydrogen-bonded 2D-network with cavities has been designed, which maintains its striking integrity after reversible water desorption-resorption processes.     

Hydrogen bond lifetimes and energetics for solute/solvent complexes studied with 2D-IR vibrational echo spectroscopy

Weak pi hydrogen-bonded solute/solvent complexes are studied with ultrafast two-dimensional infrared (2D-IR) vibrational echo chemical exchange spectroscopy, temperature-dependent IR absorption spectroscopy, and density functional theory calculations. Eight solute/solvent complexes composed of a number of phenol derivatives and various benzene derivatives are investigated. The complexes are formed between the phenol derivative (solute) in a mixed solvent of the benzene derivative and CCl4. The time dependence of the 2D-IR vibrational echo spectra of the phenol hydroxyl stretch is used to directly determine the dissociation and formation rates of the hydrogen-bonded complexes. The dissociation rates of the weak hydrogen bonds are found to be strongly correlated with their formation enthalpies. The correlation can be described with an equation similar to the Arrhenius equation. The results are discussed in terms of transition state theory.     

超临界CO2中苯甲酸与乙醇和二甲基亚砜的相互作用

在３５．０℃、１２．ＭＰａ条件下，用红外光谱法研究了超临ＣＯ２中苯甲苯与乙醇和二甲亚砜的相互作用。结果表明，在纯超临界ＣＯ２中，苯甲酸以单体和二了本的形式存在。     

Study of hydrogen-bonded clusters of 2-methoxyphenol–water

Various hydrogen-bonded clusters of 2-methoxyphenol (2MP) with water have been analyzed using ab initio methods and Atoms in Molecules (AIM) theory. The intramolecular hydrogen bond energy (and enthalpy) for 2MP was evaluated from two different methods. The results of rotational barriers method are in better agreement with experimental data. Binding energies, vibrational frequencies and geometrical parameters were examined and compared for these complexes. It was shown that in the most stable complex, water acts both as a donor and an acceptor. The “bifurcated” complex was shown to be relatively stable based on energy values. Atoms in Molecules and Natural Bond Orbital (NBO) analysis were used to confirm the existence of hydrogen bonds and to compare the strengths of them. The results obtained from quantum mechanical, AIM and NBO calculations are in agreement with each other.     

Mechanochemical Mediated Coexistence of B←N Coordination and Hydrogen Bonding

Mechanochemistry afforded a photoactive cocrystal via coexisting (B)O−H⋅⋅⋅N hydrogen bonds and B←N coordination. Specifically, solvent-free mechanochemical ball mill grinding and liquid-assisted grinding of a boronic acid and an alkene resulted in mixtures of hydrogen-bonded and coordinated complexes akin to mixtures of noncovalent complexes that can be obtained in solution in equilibria processes. The alkenes of the hydrogen-bonded assembly undergo an intermolecular [2+2] photodimerization in quantitative conversion, effectively reporting the outcome of the self-assembly processes. Our results suggest that interplay involving noncovalent bonds subjected to mechanochemical conditions can lead to functional solids where, in the current case, the structure composed of the weaker hydrogen bonding interactions predominates.     

具有形状记忆性能的P(MMA-co-HEA)/PDMS-OH氢键复合物的研究

选择低分子量端羟基聚二甲基硅氧烷(PDMS-OH)与聚(甲基丙烯酸甲酯-co-丙烯酸β-羟乙酯)P(MMA-co-HEA)共聚物原位复合形成氢键复合物,该复合物表现出良好的形状记忆效应.通过FTIR,SEM对材料的结构和形貌进行表征,DMA表征材料的动态力学行为,并通过弯曲实验对材料的形状记忆性能进行了表征及比较.FTIR分析证明PDMS-OH与P(MMA-co-HEA)共聚物形成氢键缔合作用;SEM分析显示,随着PDMS-OH含量的升高,氢键复合物由"海-岛"相分离结构向反转相分离结构转变;DMA分析结果表明,氢键的引入有利于复合物获得更高的模量比;形状记忆性能测试结果显示该氢键复合物具有良好的形状记忆性能,形状记忆固定率超过98%、形变恢复率超过99%,并且与聚(甲基丙烯酸甲酯-co-丙烯酸乙酯)/PDMS-OH(P(MMA-co-EA)/PDMS-OH)复合物相比,氢键复合物显示出更快的形变回复速率.     

Photoluminescence of 2-(2′-hydroxy-5′-methylbenzoyl)-1,5-diphenylpyrrole in aqueous and β-cyclodextrin environments: manifestation of open and closed conformers

Steady-state fluorometric studies have been performed on 2-(2′-hydroxy-5′-methylbenzoyl)-1,5-diphenylpyrrole (HMBDPP) in aqueous and aqueous β-cyclodextrin (β-CD) environments at ambient temperature. The fluorophore mostly shows a single emission in aqueous solution. Addition of β-CD to the aqueous solution of the fluorophore results in the development of another emission band at higher energy. The difference in the fluorometric behaviour is assigned to a remarkable change in the polarity of the microenvironment within the supramolecular structural environment compared to that of the bulk aqueous phase. Semi-empirical calculation (AM1-SCI) rules out the possibility of intramolecular proton transfer reaction in any of the S₀, S₁ and T₁ states of the fluorophore. It is proposed that HMBDPP exists mostly in the intermolecularly hydrogen-bonded form (open conformer) in aqueous solution while within β-CD environment, it is the intramolecularly hydrogen-bonded form (closed conformer) that predominates.     

XH-NH3(X=F,Cl,Br)质子传递的溶剂效应:簇模型,连续介质模型和离散-连续组合模型的比较

分别采用分子簇模型、连续介质模型和离散-连续组合模型研究了XH-NH3(X=F,Cl,Br)分子内质子传递的溶剂效应．结果表明,对于弱酸性化合物FH-NH3,其溶剂效应主要为短程作用,3个H2O分子即可使其发生质子传递,而简单的连续介质模型得到的仍为分子化合物形式,需进一步包含溶剂效应短程作用．对于强酸性化合物ClH-NH3和BrH-NH3,较弱的溶剂效应即可促使其发生质子传递,分子簇模型和连续介质模型均可合理描述,且与离散-连续组合模型的结果相近．离散-连续组合模型既在从头算水平考虑了溶质分子和第一溶剂化层中溶剂分子间的短程作用,又包含了溶剂效应的长程静电作用,能更准确地描述溶剂化作用,且对弱酸性化合物和强酸性化合物体系均适用．     

Theoretical Chemistry Study of the Hydrogen-bonded Interaction between Acylamine and Chloromethane Compounds

1 INTRODUCTION The mutual interaction of molecules is related with many properties of the material, such as optics, electricity and magnetism. Moreover, chemical re- action and molecule recognition are related to the mutual interaction among molecules too. So, the weak interactions among molecules have attracted many chemists’ attentions. The law of mutual interaction of molecules has been widely used in many research fields, such as, studying the mechanism of organic reaction and de- si…     

Synthesis, characterisation and molecular structure of Re(III) 2-oxacyclocarbenes stabilised by a benzoyldiazenido ligand

A family of new Fischer-type rhenium(III) benzoyldiazenido-2-oxacyclocarbenes of formula [(ReCl2[eta1-N2C(O)Ph][=C(CH2)nCH(R)O](PPh3)2][n = 2, R = H (2), R = Me (3); n = 3, R = H (4), R = Me (5)] have been prepared by reaction of [ReCl2[eta2-N2C(Ph)O](PPh3)2] (1) with omega-alkynols, such as 3-butyn-1-ol, 4-pentyn-1-ol, 4-pentyn-2-ol, 5-hexyn-2-ol in refluxing THF. The correct formulation of the carbene derivatives 2-5 has been unambiguously determined in solution by NMR analysis and confirmed for compounds 2-4 by X-ray diffraction methods in the solid state. All complexes are octahedral with the benzoyldiazenido ligand, Re[N2C(O)Ph], adopting a "single bent" conformation. The coordination basal plane is completed by an oxacyclocarbene ligand and two chlorine atoms. Two triphenylphosphines in trans positions with respect to each other complete the octahedral geometry around rhenium. The reactivity of 1 towards different alkynes and alkenes including propargyl- and allylamine has been also studied. With propargyl amine, monosubstituted or bisubstituted complexes, [(ReCl2[eta1-N2C(O)Ph][eta1-NH2CH2C triple bond CH]n(PPh3)(3-n)][n= 1 (6); n = 2 (7)], have been isolated depending on the reaction conditions. In contrast, the reaction with allylamine gave only the disubstituted complex [(ReCl2[eta1-N2C(O)Ph][eta1-NH2CH2CH=CH2]2(PPh3)] (8). The molecular structure of the monosubstituted adduct has been confirmed by X-ray analysis in the solid state.     

Theoretical study of binding interactions and vibrational Raman spectra of water in hydrogen-bonded anionic complexes: (H2O)n- (n = 2 and 3), H2O...X- (X = F, Cl, Br, and I), and H2O...M- (M = Cu, Ag, and Au)

Binding interactions and Raman spectra of water in hydrogen-bonded anionic complexes have been studied by using the hybrid density functional theory method (B3LYP) and ab initio (MP2) method. In order to explore the influence of hydrogen bond interactions and the anionic effect on the Raman intensities of water, model complexes, such as the negatively charged water clusters ((H2O)n-, n = 2 and 3), the water...halide anions (H2O...X-, X = F, Cl, Br, and I), and the water-metal atom anionic complexes (H2O...M-, M = Cu, Ag, and Au), have been employed in the present calculations. These model complexes contained different types of hydrogen bonds, such as O-H...X-, O-H...M-, O-H...O, and O-H...e-. In particular, the last one is a dipole-bound electron involved in the anionic water clusters. Our results showed that there exists a large enhancement in the off-resonance Raman intensities of both the H-O-H bending mode and the hydrogen-bonded O-H stretching mode, and the enhancement factor is more significant for the former than for the latter. The reasons for these spectral properties can be attributed to the strong polarization effect of the proton acceptors (X-, M-, O, and e-) in these hydrogen-bonded complexes. We proposed that the strong Raman signal of the H-O-H bending mode may be used as a fingerprint to address the local microstructures of water molecules in the chemical and biological systems.     

Electronic and infrared spectroscopy of jet-cooled (+/-)-cis-1-amino-indan-2-ol hydrates

The role of conformational isomerism in molecular interaction has been studied using the example of jet-cooled complexes of (+/-)-cis-1-amino-indan-2-ol with water. The two formerly evidenced conformers of (+/-)-cis-1-amino-indan-2-ol easily form hydrates and dihydrates, which have been studied by means of laser-induced fluorescence and IR/UV double resonance spectroscopy, as well as ab initio calculations. All the 1 : 1 and 1 : 2 complexes with water evidenced in this work involve "ring" structures, in which the water monomer or dimer acts as an acceptor from the NH(2) and a donor to the OH groups of (+/-)-cis-1-amino-indan-2-ol. However, the water lies externally to the indan frame in the hydrates of conformer I of (+/-)-cis-1-amino-indan-2-ol, which possesses axial NH(2) and equatorial OH groups, and above it for the hydrates with the less stable conformer II, with equatorial NH(2) and axial OH groups. Consequently, the different steric constraints which exist in the two conformers result in different hydrogen bond topologies, with an additional OH[dot dot dot]pi interaction for the hydrates of conformer II.     

The solvation of Cu2+ with gas-phase clusters of water and ammonia

A detailed study has been undertaken of the gas-phase chemistry of [Cu(H2O)N]2+ and [Cu(NH3)N]2+ complexes. Ion intensity distributions and fragmentation pathways (unimolecular and collision-induced) have been recorded for both complexes out as far as N=20. Unimolecular fragmentation is dominated by Coulomb explosion (separation into two single charged units) on the part of the smaller ions, but switches to neutral molecule loss for N>7. In contrast, collisional activation promotes extensive electron capture from the collision gas, with the appearance of particular singly charged fragment ions being sensitive to the size and composition of the precursor. The results show clear evidence of the unit [Cu(X)8]2+ being of special significance, and it is proposed that the hydrogen-bonded structure associated with this ion is responsible for stabilizing the dipositive charge on Cu2+ in aqueous solution.     

Novel aurophilic organic ligands based on 1,3-dibromo-propan-2-ol and 2-aminothiophenol

The nucleophilic substitution reactions in 1,3-dibromo-propan-2-ol and the products of its acylation under the action of 2-aminothiophenol were investigated. It was shown that the resulting derivatives containing nitrogen and sulfur donor atoms form coordination compounds in the reactions with copper(II) salts. The possibility of chemosorption of the obtained ligands and complexes containing additional disulfide fragments on the gold electrode surface with the formation of an Au-S bond was demonstrated.