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Three amino alcohols, 3-amino-1-propanol (abbreviated as 3a1pOH), 2-amino-1-butanol (2a1bOH), and 2-amino-2-methyl-1-propanol (2a2m1pOH), were reacted with quinoline-2-carboxylic acid, known as quinaldinic acid. This combination yielded three salts, (3a1pOHH)quin (1, 3a1pOHH+ = protonated 3-amino-1-propanol, quin− = anion of quinaldinic acid), (2a1bOHH)quin (2, 2a1bOHH+ = protonated 2-amino-1-butanol), and (2a2m1pOHH)quin (3, 2a2m1pOHH+ = protonated 2-amino-2-methyl-1-propanol). The 2-amino-1-butanol and 2-amino-2-methyl-1-propanol systems produced two polymorphs each, labeled 2a/2b and 3a/3b, respectively. The compounds were characterized by X-ray structure analysis on single-crystal. The crystal structures of all consisted of protonated amino alcohols with NH3+ moiety and quinaldinate anions with carboxylate moiety. The used amino alcohols contained one OH and one NH2 functional group, both prone to participate in hydrogen bonding. Therefore, similar connectivity patterns were expected. This proved to be true to some extent as all structures contained the NH3+∙∙∙−OOC heterosynthon. Nevertheless, different hydrogen bonding and π∙∙∙π stacking interactions were observed, leading to distinct connectivity motifs. The largest difference in hydrogen bonding occurred between polymorphs 3a and 3b, as they had only one heterosynton in common. 相似文献
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Hydrothermal synthesis has afforded a pair of divalent copper acetate coordination polymers containing either 4, 4′‐dipyridylamine (dpa) or 4‐pyridylisonicotinamide (4‐pina), both of which hydrogen‐bonding capable central functional groups. X‐ray crystallography revealed that both exhibit a 1D chain dimensionality. Use of the kinked tethering ligand dpa produced [Cu(OAc)2(dpa)]n ( 1 ), which possesses a simple chain based on dpa linkage of isolated copper ions. On the other hand, employing the straighter amide ligand 4‐pina generated {[Cu(OAc)2(4‐pina)] · 0.5H2O}n ( 2 ), which exhibits {Cu2O2} rhomboid dimers formed through bridging acetate ligands. Weak antiferromagnetic coupling [g = 1.984(3), J = –3.2(3) cm–1] was observed within the axial‐equatorial bridged {Cu2O2} dimers in 2 , with possible ferrimagnetism due to spin canting below 11 K. 相似文献
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应用量子化学方法,分别在气相和水溶液中对氨基酸侧链与氧化鸟嘌呤碱基对(8-oxo-G∶C)形成的三体复合物的氢键键能、几何结构、电荷分布及二阶稳定化能进行了研究.结果表明,水溶液的存在削弱了复合物中的氢键强度,电荷分布变化明显,水溶液中形成氢键位点的电荷变化量约为气相中的10倍,而几何结构变化不明显、对于酶与DNA之间的相互作用的研究需在水溶液中进行.水溶液对带电三体复合物中8-oxo-G∶C与氨基酸侧链间的氢键有较大影响,键能平均减小了69.23 k J/mol,不带电复合物仅减小了3.60k J/mol.水溶液中三体复合物中8-oxo-G∶C间的氢键受侧链的影响不大,且与侧链带电与否无关,带电复合物和不带电复合物的氢键强度分别减小了24.57和30.05 k J/mol,且二阶稳定化能越大,其对应的氢键键长越短. 相似文献
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深入理解药物分子和核酸碱基间的相互作用机制对合理设计研发新型高效药物有重要意义. 本文运用密度泛函理论B3LYP方法对核酸碱基尿嘧啶和胸腺嘧啶与药物分子槲皮素间的氢键相互作用位点进行了研究. 使用B3LYP/6-31G(d)方法优化得到了30个稳定的氢键复合物结构, 使用B3LYP/6-311++G(3df,2p)方法计算了这些复合物的结合能. 研究结果表明, 槲皮素可以使用5个不同的结合位点与尿嘧啶或胸腺嘧啶形成氢键复合物, 尿嘧啶或胸腺嘧啶可以使用3个不同的结合位点与槲皮素形成氢键复合物. 当槲皮素的结合位点固定时, 槲皮素与尿嘧啶的位点u1或胸腺嘧啶的位点t1形成的氢键作用最强, 与位点u2或位点t2形成的氢键强度最弱; 当尿嘧啶或胸腺嘧啶的作用位点固定时, 二者与槲皮素的位点qu1 形成的氢键作用最强, 与位点qu5 作用强度次之, 与位点qu3的作用强度最弱. 分子中原子(AIM)和自然键轨道(NBO)分析计算结果表明, 轨道作用在氢键中起重要作用. 相似文献
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Trans-5,10-bis(1-bromodifluoroacetyl-l-ethoxycarbonyl-methylidene)thianthrene (1b) was prepared from the reaction of BrCF2COC(N2)CO2Et with thianthrene. X-ray single crystal diffraction analysis showed that the intermolecular halogen bonding and hydrogen bonding coexisted in this compound. The bromine atom acted as an electron acceptor in the halogen bond and an electron donor in the hydrogen bond. It is the first example that the bromine atom acted as such a dual role in the hydrogen and halogen bond. 相似文献
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1-Methylpiperazine was employed to crystallize with 2,4-dihydroxybenzoic acid and 1,8-naphthalene acid, affording two multi-component hydrogen-bonding salts [(C5H14N2)2+·(C7H5O4)2-·H2O](1) and [(C5H14N2)2+(C12H6O4)2ˉ·2H2O](2). These two forms of salts are both monoclinic systems with space group P21/c(14). The lattice parameters of salts 1 and 2 are a=1.32666(10) nm, b=0.90527(7) nm, c=1.67107(13) nm, β=103.125(1)° and a=1.4950(2) nm, b=0.75242(15) nm, c=1.6563(3) nm, β=92.834(2)°, respectively. Expected classical hydrogen bonds N―H…O and O―H…O appear in the chargetransfer salts, and asymmetric units of these two forms both contain water molecules which play a significant role in building novel supramolecular architectures. Robust hydrogen-bond interactions between 1-methylpiperazine and aromatic acid provide sufficient driving force to direct the two crystals to three-dimensional structures. Weak interactions C―H…O emerging in salts 1 and 2 further enhance their crystal structures. As a consequence, hydrogen-bonding interactions in these compounds afford diverse 3D net supramolecular architectures. Thermal stability of these compounds was investigated by thermogravimetric analysis(TGA). 相似文献
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A model is proposed to rapidly evaluate the individual hydrogen bonding energies in linear water chains. We regarded the two O--H bonds of a water molecule as two dipoles. The magnitude of the O--H bond dipole mo- ment can be varied due to the other water molecules' presence. An analytic potential energy function, which explicitly contains the permanent dipole-dipole interactions, the polarization interactions, the van der Waals interactions and the covalent interactions, was therefore established. The individual hydrogen bonding energies in a series of linear water chains were evaluated via the analytic potential energy function and compared with those obtained from the CP-corrected MP2/aug-cc-pVTZ calculations. The results show that the analytic potential energy function not only can produce the individual hydrogen bonding energies as accurately as the CP-corrected MP2/aug-cc-pVTZ method, but is very efficient as well, demonstrating the model proposed is reasonable and useful. Based on the individual hy- drogen bonding energies obtained, the hydrogen bonding cooperativity in the linear water chains was explored and the natures of the hydrogen bonding in these water chains were discussed. 相似文献
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The synthesis and characterisation of a series of [RuII(bpy)2L] and [Ir(ppy)2L] complexes containing ligands L with the potential to engage in triple hydrogen bonding interactions is described. L1 and L2 comprise pyridyl triazole chelating units with pendant diaminotriazine units, capable of donor‐acceptor‐donor (DAD) hydrogen bonding, while L3 and L4 contain ADA hydrogen bonding units proximal to N^N and N^O cleating sites, respectively. X‐ray crystallography shows the L1 and L2 containing RuII complexes to assemble via hydrogen bonding dimers, while [RuII(bpy)2L 4 ] assembles via extended hydrogen bonding motifs to form one dimensional chains. By contrast, the expected hydrogen bonding patterns are not observed for the RuII and IrIII complexes of L3 . Spectroscopic studies show that the absorption spectra of the complexes result from combinations of MLCT and LLCT transitions. The L1 and L2 complexes of IrIII and RuII complexes are emissive in the solid state and it seems likely that hydrogen bonding to complementary species may facilitate tuning of their 3ILCT emission. Low frequency Raman spectra provide further evidence for ordered interactions in the solid state for the L4 complexes, consistent with the results from X‐ray crystallography. 相似文献
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The synthesis and crystal structures of guanidinium monofluorophosphate and hydrogen monofluorophosphates with the following cations: piperazinium, di‐ and triethylammonium, guanidinium, and dimethyluronium, are described and discussed. The structures of the acid salts consist of hydrogen‐bonded HPO3F tetrahedra, which form infinite chains or cyclic dimers. The organic cations link these units together. All of the hydrogen bond systems observed consist of short O—H···O and longer N—H···O bonds. No O—H···F or N—H···F bonds were found. The F atom avoids hydrogen acceptor positions in the structures. The thermal behavior of [NHEt3]HPO3F was also studied. 相似文献
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分子筛在催化、吸附和离子交换等方面具有广泛的应用 ,一直是重要的工业材料 .自 1 982年Wilsion首次合成磷酸铝以来 [1] ,人们发现磷酸盐具有类似于分子筛的结构特征 [2~ 4 ] ,随着研究的不断深入 ,近来具有空旷结构的磷酸盐分子筛由于在催化、光学、磁学等领域具有潜在的应用前景日益受到人们的关注 .具有微孔结构的过渡金属磷酸盐因可作为分子反应器而使许多新的过渡金属磷酸盐被合成出来[5~ 9] .文献 [1 0 ,1 1 ]报道 Co PO4 具有层状、多孔、高聚合度的结构 ,这些分子多数经过有机模板剂或其它分子的修饰 ,形成混合配体的配合物 .… 相似文献
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The geometric structures, infrared spectra and hydrogen bond binding energies of the various hydrogen‐bonded Res?‐water complexes in states S0 and S1 have been calculated using the density functional theory (DFT) and time‐dependent density functional theory (TD‐DFT) methods, respectively. Based on the changes of the hydrogen bond lengths and binding energies as well as the spectral shifts of the vibrational mode of the hydroxyl groups, it is demonstrated that hydrogen bonds HB‐II, HB‐III and HB‐IV are strengthened while hydrogen bond HB‐I is weakened in the four singly hydrogen‐bonded Res?‐Water complexes upon photoexcitation. When the four hydrogen bonds are formed simultaneously between one resorufin anion and four water molecules in the Res?‐4Water complex, all the hydrogen bonds are weakened in both the ground and excited states compared with those in the corresponding singly hydrogen‐bonded Res?‐Water complexes. Furthermore, in complex Res?‐4Water, hydrogen bonds HB‐II and HB‐IV are strengthened while hydrogen bonds HB‐I and HB‐III are weakened after the electronic excitation. The hydrogen bond strengthening and weakening in the various hydrogen‐bonded Res?‐water complexes should be due to the redistribution of the charges among the four heteroatoms (O1‐3 and N1) within the resorufin molecule upon the optical excitation. 相似文献
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The reaction of phenols and dihydroxybenzenes with epoxide in the presence of nano CaCO3 was studied. Catechol could react with epoxide and gave monochlorohydrin derivative; other dihydroxybenzenes and monomeric phenols had no reaction under the same conditions. The reaction of catechol with epoxide did not occur when nano CaCO3 was replaced by a normal one. These were attributed to the strong interaction between nano CaCO3 and the substrate as catechol possessed intrahydrogen bond and excess active hydrogen, which can induce the intramolecular proton transfer via the intramolecular hydrogen bond and promote the reaction of hydroxyl and epoxide. This is an example revealing the unique role of the hydrogen bond played in chemical reactions. 相似文献
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具有内孔道的层状超分子化合物[(CuI)2(o-phen)2]的水热合成与晶体结构 总被引:4,自引:0,他引:4
固态金属配位超分子的晶体工程是化学和分子科学最活跃的研究领域之一, 它不仅因存在内孔和隧道等新颖网络特殊性而具有理论研究价值, 而且在催化、光学、主-客体化学以及分子电学等领域中具有巨大的潜在应用价值[1~8]. 用于构筑这类功能化合物的方法主要依赖于构筑网络的相互作用, 即利用分子间的氢键, π-π作用及其它的分子间弱的相互作用. 由于Cu-X体系超分子化合物优异的光学和催化性能, 它们的合成与表征近来已引起人们的极大兴趣[9,10]. 相似文献
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在水热条件下(120 ℃), 将醋酸锰、4,4'-联吡啶(4,4'-bpy)与9-蒽酸(9-HAC)反应, 得到了配位聚合物[Mn(9-AC)2(4,4'-bpy)(H2O)2]n, 通过元素分析、红外光谱、X射线单晶衍射对其进行了表征, 并用TGA研究了该配位聚合物的热稳定性. 结构解析结果表明, 该晶体属于正交晶系, Fdd2空间群, a=1.66772(12) nm, b=3.36471(16) nm, c=1.1687(4) nm, V=6.558(2) nm3, Z=8, Mr=689.60, Dc=1.397 Mg/m3, R=0.0356, wR2 = 0.0604. 在该配位聚合物中, 中心锰原子采取略微变形的八面体构型, 与两种配体共同构筑了一维直线形链结构, 链与链之间通过氢键相互作用构筑成三维超分子网络. 相似文献
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本文设计并合成了一个具有共价有机骨架微孔结构的聚三(4-苯基)硅醇化合物。该化合物是利用乌尔曼反应,三(4-溴苯基)硅醇自聚合得到的。通过MAS NMR,FTIR,SEM,PXRD对化合物结构进行了表征。并通过TGA及氮气吸附表征化合物热稳定性及孔性质。该化合物具有高热稳定性(467 ℃失重5%),高化学稳定性,高BET比表面积(739 m2g-1)及很窄的孔径分布(1.27 nm)。 相似文献
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Natalie Schäfer Michael Bühler Lisa Heyer Dr. Merle I. S. Röhr Priv.-Doz. Dr. Florian Beuerle 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(19):6077-6085
A highly strained covalent organic cage compound was synthesized from hexahydroxy tribenzotriquinacene (TBTQ) and a meta-terphenyl-based diboronic acid with an additional benzoic acid substituent in 2’-position. Usually, a 120° bite angle in the unsubstituted ditopic linker favors the formation of a [4+6] cage assembly. Here, the introduction of the benzoic acid group is shown to lead to a perfectly preorganized circular hydrogen-bonding array in the cavity of a trigonal-bipyramidal [2+3] cage, which energetically overcompensates the additional strain energy caused by the larger mismatch in bite angles for the smaller assembly. The strained cage compound was analyzed by mass spectrometry and 1H, 13C and DOSY NMR spectroscopy. DFT calculations revealed the energetic contribution of the hydrogen-bonding template to the cage stability. Furthermore, molecular dynamics simulations on early intermediates indicate an additional kinetic effect, as hydrogen bonding also preorganizes and rigidifies small oligomers to facilitate the exclusive formation of smaller and more strained macrocycles and cages. 相似文献