Crystal Structure of 2,6-Dihistidine Dimethyl Ester Pyridine Acylamine Monohydrate

The crystal structure of the title compound,C21H25N7O7,has been determined in the orthorhombic space group C222(1) with a=8.993(10),b=12.149(14),c=22.20(2) and Z=4.There exist intramolecular C-H…O and N-H…N hydrogen bonds in the title crystal structure.The intermolecular N-H…N and C-H…O hydrogen bonds together with π-π stacking interactions(face-to-face) link the molecules into an infinite three-dimensional supramolecular network.     

Syntheses and Structural Characterization of 1-（4-Phenyl-2-thiazolyl）-3-（4-methylphenyl）-5-（2-furyl）-4,5-dihydro-（1H）-pyrazole and 1-（4-（4-Fluoro）phenyl-2-thiazolyl）-3-（4-methyl-phenyl）-5-（2-furyl）-4,5-dihydro-（1H）-pyrazole

The title compounds were synthesized and characterized by IR,1H-NMR,Mass and elementary analysis and single-crystal X-ray diffraction.In 1a,intermolecular C-H…π interactions produce a three-dimensional network.In 1b,intermolecular C-H…O hydrogen bonds generate an R22(22) ring.The hydrogen bonding is supported by C-H…π interactions.     

Hydrogen Bonding Assembled 3D Supramolecular Structures Formed by 5-Amino-2,4,6-triiodoisophthalic Acid and N-Heterocyclic Aromatic Ligands

Three salts constructed by 5-amino-2,4,6-triiodoisophthalic acid(ATIPA) with N-heterocycles aromatic coformers such as pyridine tetrazolium, tetramethylpyraziiie and cyanuric acid were synthesized by slowing evaporation of solvent. X-Ray single crystal analysis shows that hydrogen protons of the carboxyl groups transfer to nitrogen atoms of the N-heterocyclic coformers to form N-H…0 hydrogen bonds in all the three compounds. A huge amount of H-bonds play significant role in tlie construction of these compounds and all of them generate 3D structures through strong O-H…N, O-H…O, N-H…O and weak C-H…O hydrogen bonds. Moreover, solvent water molecules are indispensable in the formation of compounds 1 and 3, which constitutes different supramolecular synthons to bridge individual molecules and chains to form stable structures. In addition, these crystal structures were further characterized by themiogravimetric analysis and infrared spectroscopy.     

Theoretical Studies on the Hydrogen Bonds of Different Position Action Mechanisms of Thymine with Uracil

In this research, the hydrogen bonds Y···H-X(X = C, N; Y = N, O) of thymine and uracil have been theoretically studied. The results show that hydrogen bond leads to bond length elongation and stretches the frequency red-shift of N-H···Y. Meanwhile, the C-H···O bonds shorten and stretch the frequency blue-shift. They all belong to traditional hydrogen bonds. The intermolecular charge transfer caused by the intermolecular hyperconjugation ρ*(N–H) →n(Y) and intramolecular charge redistribution by intramolecular hyperconjugation ρ(C-H)→ρ*(C-N) play important roles in the formation of hydrogen bonds. According to the judgment standards proposed by Bader and Popelier, these hydrogen bonds have typical electron density topological properties. Electrostatic surface potential(ESP) is a useful physicochemical property of a molecule that provides insights into inter- and intramolecular associations, as well as the prediction of likely sites of electrophilic and nucleophilic metabolic attack.     

Syntheses, Crystal Structures and Fluorescence Properties of Two Triazolyl Derivatives with Biphenyl Links

Two novel triazolyl derivatives with biphenyl links, namely 4,4-bis（1,2,4-triazol-1-ylmethyl）biphenylene 1 and 4,4-bis（3,5-dimethyl-1,2,4-triazol-1-ylmethyl）biphenylene 2, have been synthesized and structurally characterized by single-crystal X-ray diffraction. Compounds 1·H2O·HCl and 2·2H2O·2HCl crystallize in the monoclinic system with space group C2/c and P21/c, respectively. The dihedral angles of the two phenyl rings are 30.26（6）° in 1·H2O·HCl, while co-planar （0.00（7）°） in 2·2H2O·2HCl. In 1·H2O·HCl, the N-H…O hydrogen bonds link 1 to form chain-like structures which are further connected by O-H…Cl, C-H…Cl, C-H…O and π-π supramolecular interactions. The hydrogen bonds of O-H…Cl in 2·2H2O·2HCl provide distinguishing P/M helical chains along the b axis, and these chains are further connected by N-H…O hydrogen bonds to generate a 2D structure. Compounds 1 and 2 in methanol solution show much stronger emission bands at 319 nm than biphenyl at 316 nm under excitation at 260 nm.     

Two Cd(Ⅱ) and Cu(Ⅱ) Complexes Based on 1-Butylbenzimidazole: Crystal Structures and Weak Interactions

1-Butylbenzimidazole L reacted with Cd(NO3)2·4H2O to afford complex [CdL(NO3)3H2O]·[HL] 1. The heptacoordinated Cd(Ⅱ) center adopts a distorted pentagongal bipyramidal geometry, and complex [CdL(NO3)3H2O]-entity and the protonated benzimidazium salt [HL]+ are connected via N-H···O hydrogen bond to form a dimeric unit [CdL(NO3)3H2O]·[HL]. A 3-D supramolecular network of 1 is formed through N-H···O and O-H···O hydrogen bonds together with π-π stacking interactions. Reaction of L with CuCl2 afforded a mononuclear complex, [CuL2Cl2] 2, in which the tetracoordinated Cu(II) center adopts a distorted tetrahedral geometry. In contrast, 2-D supramolecular layers of 2 are formed by C-H···Cl hydrogen bonds. The fluorescent emission spectra of L, 1 and 2 are described.     

The open-close mechanism of M2 channel protein in influenza A virus:A computational study on the hydrogen bonds and cation-π interactions among His37 and Trp41

The M2 protein from influenza A virus is a tetrameric ion channel. It was reported that the permeation of the ion channel is correlated with the hydrogen bond network among His37 residues and the cation-π interactions between His37 and Trp41. In the present study,the hydrogen bonding network of 4-methyl-imidazoles was built to mimic the hydrogen bonds between His37 residues,and the cation-π interactions between 4-methyl-imidazolium and indole systems were selected to represent the interac-tions between His37 and Trp41. Then,quantum chemistry calculations at the MP2/6-311G level were carried out to explore the properties of the hydrogen bonds and the cation-π interactions. The calcula-tion results indicate that the binding strength of the N-H···N hydrogen bond between imidazole rings is up to -6.22 kcal·mol-1,and the binding strength of the strongest cation-π interaction is up to -18.8 kcal·mol-1(T-shaped interaction) or -12.3 kcal·mol-1(parallel stacking interaction). Thus,the calcu-lated binding energies indicate that it is possible to control the permeation of the M2 ion channel through the hydrogen bond network and the cation-π interactions by altering the pH values.     

Syntheses,Crystal Structures and Intermolecular Interactions of Cu（II） Complexes with Methyl- benzoic Acid （MBA） and 1,10-Phenanthroline

Two cupric complexes containing methylbenzoic acid have been prepared and crystallized by solvent evaporation method in DMF. The single-crystal X-ray crystallographic analysis reveals that they are dicaryon complexes. Complex I with formula of [Cu2（m- MBA）4DMF2] crystallizes in monoclinic with space group of P21/c and complex 2 with formula of [Cuz（o-MBA）ffo-phen）2]·NO3·H2O crystallizes in triclinic with space group of P I. The weak interactions including C-H...O hydrogen bonds, C-H…π interactions and π-π stacking in the structures of two complexes are observed from the X-ray crystallographic data. In addition, there are still classical hydrogen bonds in 2. The different strength of intermolecular interaction in the structure is reflected on their different thermal stability measured by thermal gravimetric analysis and 2D-1R correlation spectroscopy of two complexes. The study of weak interactions is meaningful to provide supporting data for supramolecular chemistry theory and potential applications in molecular biology.     

Synthesis and Crystal Structure of a Copper(II) Compound Constructed by N-(4,6- Dimethoxylpyrimidin)-N'-(ethoxycarbonyl)thiourea

A copper(Ⅱ) complex Cu(L)2(NO3)2 constructed by the L (L = N-(4,6-dime- thoxylpyrimidin)-N'-(ethoxycarbonyl)thiourea) ligand crystallizes in monoclinic, space group C2/c with a = 16.2416(16), b = 9.1385(7), c = 22.0008(18) (A),β = 108.077(2)°, V ＝ 3104.3(5)(A)3, Dc = 1.627 g/cm3, Z = 4, C20H28CuN10O14S2, Mr = 760.18, μ(MoKα) = 0.920 mm-1, F(000) = 1564, R = 0.0471 and wR = 0.1284 for 2239 observed reflections (I > 2σ(I)). X-ray diffraction shows the existence of weak complementary intramolecular N-H…O (DA) hydrogen bonds which further strengthen the coordination from the two L ligands with the Cu(II) ion, intermolecular C-H…O hydrogen bonds and weak π…π stacking interactions, leading to the formation of a multi-dimen- sional supramolecular network.     

Synthesis and Crystal Structure of Bis{2-bromo- 4-chloro-6-[(2-isopropylammonioethylimino)-methyl]phenolato}bisthiocyanatozinc(Ⅱ)

A Schiff base zinc(Ⅱ) complex [Zn(C12H16BrClN2O)2(NCS)2] was prepared and characterized by elemental analysis, IR and single-crystal X-ray diffraction. The crystal belongs to the triclinic system, space group P with a = 8.414(1), b = 9.124(1), c = 22.212(3) (A), α = 79.177(2), β = 86.296(2), γ = 89.899(2)o, V = 1671.3(4) (A)3, Z = 2, Dc = 1.631 g/cm3, Mr = 820.79, λ(MoKα) = 0.71073 (A), μ = 3.444 mm-1, F(000) = 824, R = 0.0646 and wR = 0.1179. A total of 7371 unique reflections were collected, of which 3904 with I＞2σ(I) were observed. The complex crystallizes with two half-molecules per asymmetric unit and each mononuclear molecule is centrosymmetric. The Zn atom lying at the inversion centre is six-coordinated in a slightly distorted octahedral geometry by two phenolate O atoms and two imine N atoms from two Schiff base ligands, as well as two N atoms from two thiocyanate anions. In the crystal structure, the combination of π-π stacking interactions and intermolecular hydrogen bonds (N-H…Br, N-H…O, N-H…N, C-H…O, C-H…S and C-H…Cl) leads to a three-dimensional network.     

4-Amino-3-（p-chlorophenyl）-5-（p-methoxybenzyl）-4H-1,2,4-triazole：X-ray and DFT-calculated Structures

The title compound, 4-amino-3-(p-chlorophenyl)-5-(p-methoxybenzyl)-4H-1,2,4- triazole I , C16H15ClN4O), has been determined using X-ray diffraction techniques and the molecular structure has also been optimized at the B3LYP/6-31 G(d, p) level using density functional theory (DFT). The triazole ring exhibits dihedral angles of 41.61(15)o and 80.73(11)o with the phenyl rings. The molecules are linked principally by N–H…N hydrogen bonds involving the amino NH2 group and a triazole N atom, forming C(5) chains which are further linked to give a two-dimensional network of molecules. The N–H…N hydrogen bonding is supported by C–H…N hydrogen bond and C–H…π interaction. Intermolecular N–H…N and C–H…N hydrogen bonds produce R22(9), R44(10) and R44(20) rings.     

Synthesis and Crystal Structure of a Novel Three-dimensional Supramolecular Compound [（AgI3）（4-HBPFA）2（H2O）]

1 INTRODUCTION In recent years, the rational design and synthesisof metal-directed supramolecular frameworks throughintermolecular hydrogen bonds, π-π stacking interac-tion or other weak interactions have received muchattention because of their interesting molecular topo-logies and various potential applications in catalysis,superconductor, magnetism, nonlinear optics, sen-sors and molecular recognition[1～4]. On the otherhand, the attachment of mono- or polypyridyl frag-ments to a ferr…     

A novel Zn(II) complex based on 1H-1,2,3-benzotriazol-1-ylacetic acid and 1H-1,2,3-benzotriazole ligands: Synthesis, crystal structure, and photoluminescent property

A novel complex formulated as [Zn(HBTA)₂(L)₂] · 2H₂O (I), where HL = 1H-1,2,3-benzotriazol-l-ylacetic acid, HBTA = 1H-1,2,3-benzotriazole, has been synthesized and structurally characterized by single crystal X-ray diffraction. Complex I shows a mononuclear structure, which is assembled into 1D chain via intermolecular π…π interactions and N-H…O hydrogen bonds. Different chains are linked by C-H…O hydrogen bonds into 2D layer. The photoluminescence property of the complex has been investigated.     

Synthesis and Structure of 1.5Zn（phen）3·L·3NO3 Supramolecule （phen = o-Phenanthroline,L = 4-Aminoacetophenone Thiosemicarbazone）

A supramolecular framework, 1.5Zn（phen）3·L·3NO3 （C63H48Zn1.5N16O9S）, has been synthesized. The ligand L was synthesized by the condensation of p-aminoacetophenone with thiosemicarbazide. The crystal belongs to the monoclinic system, space group C2/c, with a = 31.005（2）, b = 15.114（2）, c = 24.887（3） A, β = 94.260（2）° Z = 8, V = 11630（2）A^3 Dc = 1.489 g/cm^3, Mr = 1303.29,λ（MoKa） = 0.71069 A,μ= 0.735 mm^-1, F（000） = 5368, Rint = 0.0699, R= 0.0505 and wR= 0.0707. Two independent Zn atoms are both coordinated by six N atoms from three phen ligands. π-π and C-H…π interactions among the L ligands and Zn（phen）3 cations, π-π and C-H...π interactions among the Zn（phen）3 cations and N-H...O hydrogen bonds among the L ligands and nitrate anions connect the whole structure into a 3-D supramolecular framework.     

多重氢键自组装联萘酚和含氮化合物

作为相互识别的结果,(±)-2,2′-二羟基-1,1′-联萘酚可与4,4′,6,6′-四甲基-2,2′-联嘧啶、1,2-双(4-吡啶)乙烷、反式-1,2-双(4-吡啶)乙烯、4,4′-联吡啶-N,N′-双氧化物及双-2-吡啶基甲酮等多种含氮化合物分别形成外形良好的共晶化合物1,2,3,4及5.本文对5个共晶化合物的晶体...