Assessment of intermolecular N–H…F and N–H…Cl hydrogen bonding in stabilising hetero- and homodimers in solution

This paper describes the first assessment of intermolecular weak N–H…F and N–H…Cl hydrogen bonding in stabilising hetero- and homodimers in solution. Aromatic amide and urea monomers have been designed and synthesised. The association constants of the heterodimers formed by two complementary monomers and the homodimers formed by self-complementary monomers have been determined by using ¹H titration and dilution experiments. The results show that both N–H…F and N–H…Cl hydrogen bonds are able to stabilise the corresponding dimers to a measurable extent, even though the stability of the dimers is generally low.     

Interaction between tetramethylcucurbit[6]uril with α-furaldehyde-isonicotinyl-hydrazone hydrochloride

Interaction between tetramethylcucurbit[6]uril (TMeQ[6], host) and the hydrochloride salt of α-furaldehyde-isonicotinyl-hydrazone hydrochloride (FIHH⁺, guest) was investigated using X-ray crystallography and spectroscopic methods. X-ray crystallography showed that the π–π stacking effect and hydrogen bonding resulted in the formation of a dumbbell-shaped supramolecule which contained two FIHH⁺@TMeQ[6] host–guest inclusion complexes. The host–guest interaction provided identifiable changes in the vibrational frequencies in the IR spectra. ¹H NMR spectral analysis established a similar interaction model and revealed that TMeQ[6] preferred to include the furan moiety over the pyridine moiety of the FIHH⁺ guest molecule. Absorption spectrophotometric analysis suggested that the host and guest interact in a ratio of 1:1 with a stability constant K _s = (3.52 ± 0.74) × 10⁶ l mol^? 1.pH titration confirmed that the host–guest interaction led to a clear change in the protonation constant of the title guest. Quantum chemical calculations were used to determine the possible mechanism of formation of the dumbbell-shaped complex.     

超分子三维氢键网络：{[Cu(phen)3](SO4)(H3PCA)2(8H2O)}的晶体结构

A new complex， {[Cu(phen)₃](SO₄)(H₃PCA)₂(8H₂O)}， was synthesized and structurally characterized by single-crystal X-ray analysis. The complex is composed of copper cations， sulfate anions， 1，10-phenanthroline， protocatechuic acid and lattice water molecules. The structure of H₃PCA， SO₄^2- and waters comprises packing of anionic three-dimensional network by hydrogen bonds with cavities. The complex can be considered as a model of host/guest supramolecule. The three-dimensional hydrogen-bonding network is the host species. The Cu(phen)₃²⁺ cations， guest species， occupied the cavities of the host. And the results demonstrate that the form of protocatechuic acid at pH< 1 should be free ligand. CCDC： 191733.     

C(4) helices,Br⋅<Emphasis Type="Italic">s</Emphasis>Br interaction and <Emphasis Type="Italic">R</Emphasis><Stack><Subscript>4</Subscript><Superscript>2</Superscript></Stack> (10) ring in bromoipriflavone

The title compound, 8-bromo-7-isopropoxyisoflavone (bromoipriflavone), C₁₈H₁₅O₃Br, crystallizes in tetragonal crystal system, space group I4₁/a with cell constants a = 21.396(2) Å, c = 13.588(2) Å, V = 6220.2(14) ų and Z = 16. Bromoipriflavone is composed of a benzopyranone moiety, a phenyl moiety, an isopropoxy group and a bromine atom. The benzopyranone ring is not coplanar with the phenyl ring with a dihedral angle of 55.1. The molecules are stacked into a C(4) helices down [001] via – stacking and hydrogen bonds, the C(4) helices are assembled into three-dimensional network via strong BrsBr interactions and synthons R₄²(10) formed by two tri-centered C–HsO hydrogen bonds, resulting in a distinctive high-symmetry supramolecule. The title compound was also characterized by IR and ¹H NMR.     

β-环糊精与水杨酸包合物的合成与结构

合成了β-环糊精与水杨酸的包合物b-cyclodextrin-salicylic acid (β-CD-sal) [(C₄₂H₇₀O₃₅)₂•(C₇H₆O₃)₂•(H₂O)₂₄], 用X射线单晶衍射、元素分析和核磁共振对其分子结构进行了表征. X射线单晶衍射结果表明: 包合物的晶体属于单斜晶系, 空间群为C₂, a＝1.9269(5) nm, b＝2.4395(7) nm, c＝1.6095(4) nm, β＝107.816(5)°, V＝7.203(3) nm³, Z＝4, D_c＝1.373 g•cm^－3, F(000)＝3176, R[I＞2σ(I)]＝0.0971. 在形成的2∶2包合物中, β-环糊精通过羟基间的氢键形成头对头的二聚体, 两个水杨酸分子以不同的形式与环糊精形成包合物, 其中一个水杨酸分子寄居于环糊精的空腔中, 而另一个水杨酸则位于由两个环糊精形成二聚体的空隙中.     

几个超分子体系中非常规键的AIM分析

对五个含氟分子自组装形成的晶体进行了AIM (Atoms in Molecules)分析, 观察到、并定量地描述了这些晶体中大量存在的氟原子相关的非常规弱相互作用力; 并且找到一个完全由F…O弱相互作用主导的超分子自组装晶体.     

新型异三聚体超分子的密度泛函计算及其晶体结构、热性能研究

运用密度泛函B3LYP方法，在6-31G^*水平上设计优化了丁二酮肟与苯甲酸通过四重氢键构筑的异三聚体超分子、此异三聚体的总能量比三个单体总能量之和低144．0816kJ／mol，四重氢键的平均键能约为36．0204kJ／mol，属中高强度；298．15K时吉布斯自由能变化△GT=-41．70kJ／mol，显示形成三聚体的反应可自发进行．在此设想指导下，实验合成出相关异三聚体，并得到了晶体结构，与预测的结构极为相似．热性能分析显示，此三聚体不是三个单体的简单叠加，而是一个不同于其单体的全新化合物．理论计算数据与实验结果的一致性，证明了理论计算的预见性．     

配合物型非线性光学材料的晶体工程

以分子基材料为目标的功能配合物的设计合成是近年来材料化学研究的重要领域，传统的分子设计尽管在分子水平上获得了很大的成功，但在由分子到晶体，由微观性质到宏观功能的晶体工程研究中遇到了极大的困难。因为宏观功能不仅要求分子本身具有良好的性能，同时还要求分子按照一定的方式堆积和排列犤１～３犦。例如二阶非线性光学材料不但要求分子具备较大的非线性超极化率和非对称中心，而且还要求分子在堆积过程中形成无心空间群的晶体。而自然界中大约超过７０％的手性分子在结晶时都形成有心的空间群，因此，如何实现分子的无心堆积是非…     

A Strategy for Synthesis of Ion‐Bonded Supramolecular Star Polymers by Reversible Addition‐Fragmentation Chain Transfer (RAFT) Polymerization

We have developed a novel strategy for the preparation of ion‐bonded supramolecular star polymers by RAFT polymerization. An ion‐bonded star supramolecule with six functional groups was prepared from a triphenylene derivative containing tertiary amino groups and trithiocarbonate carboxylic acid, and used as the RAFT agent in polymerizations of tert‐butyl acrylate (tBA) and styrene (St). Molecular weights and structures of the polymers were characterized by ¹H NMR and GPC. The results show that the polymerization possesses the character of living free‐radical polymerization and the ion‐bonded supramolecular star polymers PSt, PtBA, and PSt‐b‐PtBA, with six well‐defined arms, were successfully synthesized.