Direct Evidence for the Effect of Intermolecular Hydrogen Bonding on Organogels

In order to get direct evidence for the effect of intermolecular hydrogen bonding on the organogels, one arnide group in N-（3, 4, 5-octyloxybenzoyl）-N＇-（4＇-aminobenzoyl）hydrazine（D8） was replaced by a Schiff base group, forming N-（3,4,5-octyloxybenzoyl）-N＇-（4＇-amidobenzoyl） acylhydrazone（T8SchA）. D8 and T8SchA organogels in cyclohexane show the same hexagonal columnar structure. And the hydrogen bonding was demonstrated to be still interacting in the organogels. However, although the molecular geometry of D8 was well retained in T8SchA, the molecular dipole moment of T8SchA is bigger than that of D8 due to the reduction of the number of hydrogen bonds. Thus, the decreased gelling stability of T8SchA compared to that of D8 can only be attributed to the reduction of the number of intermolecular hydrogen bonds, which provides direct evidence that intermolecular hydrogen bonding plays an important role in stabilising organogels.

Theoretical Investigations into the Intermolecular Hydrogen-bonding Interactions between Azacyclopentane-2-one and N-Methylol Ethanone

The structures of the complexes formed between N-methylol ethanone （model molecule of ceramide） and azacyclopentane-2-one （the model molecule of azone） have been fully optimized at the B3LYP/6-311＋＋G＊＊ level. The intermolecular hydrogen bonding interaction energies have been calculated by using the B3LYP/6-311＋＋G＊＊, B3LYP/6-311＋＋G（2df,2p）, MP2（full）/6-311 ＋＋G＊＊ and MP2（full）/6-311 ＋＋G（2df,2p） methods, respectively. The results show that strong O-H…O=C, N-H…O=C and C-H…O=C hydrogen bonds could exist between azacyclopentane-2-one and N-methylol ethanone. The formation of the complexes might change the conformation of ceramide molecule and thus cause better percutaneous permeation for the drugs. This is perhaps the origin of the permeation enhances the activity of azone for medicament, as is in accordance with the experimental results. The hydrogen-bonding interactions follow the order of （a） 〉 （c） 〉 （b） 〉 （d） 〉 （g） ≈ （e） ≈ （i） 〉 （h） 〉 （f）. The analyses of frequency, NBO, AIM and electron density shift are used to further reveal the nature of the complex formation. In the range of 263.0- 328.0 K, the complex is formed via an exothermic reaction, and the solvent with lower temperature and dielectric constant is favorable to this process.

Investigation of inter-molecular hydrogen bonding in the binary mixture (acetone+water) by concentration dependent Raman study and ab initio calculations

This paper reports that vibrational spectroscopic analysis on hYdrogen-bonding between acetone and water comprises both experimental Raman spectra and ab initio calculations on structures of various acetone/water complexes with changing water concentrations. The optimised geometries and wavenumbers of the neat acetone molecule and its complexes are calculated by using ab initio method at the MP2 level with 6-311＋G（d,p） basis set. Changes in wavenumber position and linewidth （fullwidth at half maximum） have been explained for neat as well as binary mixtures with different mole fractions of the reference system, acetone, in terms of intermolecular hydrogen bonding. The combination of experimental Raman data with ab initio calculation leads to a better knowledge of the concentration dependent changes in the spectral features in terms of hydrogen bonding.

Theoretical verification of intermolecular hydrogen bond induced thermally activated delayed fluorescence in SOBF-OMe

Thermally activated delayed fluorescence(TADF)molecules have attracted great attention as high efficient luminescent materials.Most of TADF molecules possess small energy gap between the first singlet excited state(S_(1))and the first triplet excited state(T_(1))to favor the up-conversion from T_(1)to S_(1).In this paper,a new TADF generation mechanism is revealed based on theoretical simulation.By systematic study of the light-emitting properties of SOBF-OMe in both toluene and in aggregation state,we find that the single SOBF-OMe could not realize TADF emission due to large energy gap as well as small up-conversion rates between S_(1)and T_(1).Through analysis of dimers,we find that dimers with intermolecular hydrogen bond(H-bond)are responsible for the generation of TADF,since smaller energy gap between S_(1)and T_(1)is found and the emission wavelength is in good agreement with experimental counterpart.The emission properties of SOBF-H are also studied for comparison,which reflect the important role of H-bond.Our theoretical results agree ith experimental results well and confirm the mechanism of H-bond induced TADF.

Density Functional Theory Studies on the Intermolecular Interactions of Five Aza-calix[6]arene Host with HMX

Five fully optimized structures of complexes between aza-calix[6]arene host monomers（Ma～Me） and complexes（a～e） have been obtained at the B3LYP/6-31G（d） level.Natural bond orbital（NBO） analysis was performed to reveal the origin of the interaction.The intermolecular interaction energy was evaluated with basis set superposition error correction（BSSE） and zero point energy correction（ZPEC）.The B3LYP/6-31G（d） calculations on the five complexes have shown that the greatest interaction（–13.98 kJ/mol） is found in the complex between HMX and hexa-aza-calix[3]-p-tri-arene[3]-2-amido-1,3,5-tri-azine.The results have indicated that intermolecular interaction energies of aza-calix[6]arenes with substituted group are stronger than those without substituted group,and those with amido are greater than with nitryl.Thus,hexa-azacalix[3]-p-tri-arene[3]-2-amido-1,3,5-tri-azine is rather equal to eliminate HMX from explosive waste water.

Synthesis and Crystal Structure of Co(DMSO)_2(H_2O)_2(SCN)_2 with One-dimensional Hydrogen-bonded Structure (DMSO = Dimethylsulfoxide)

The title complex Co（DMSO）2（H2O）2（SCN）2 has been prepared and structurally characterized. It crystallizes in monoclinic, space group P21/n with a= 5.1981（9）, b = 11.944（2）, c = 12.646（2） A,β = 98.686（2）°, V = 776.2（2） A^3, C6H16CoN2O4S4, Mr = 367.38, Z = 2, De = 1.572 g/cm^3, F（000） = 378 and μ（MoKa） = 1.646 mm^-1. The structure was refined to R= 0.0232 and wR = 0.0645 for 1241 observed reflections with I 〉 2σ（I）. In the title complex, each Co（II） atom is octahedrally coordinated by four O atoms from two DMSO ligands and two water molecules as well as two N atoms from SCN^- ions. The title molecules are connected to each other through intermolecular hydrogen bonds to form a 1-D structure extended by eight-membered Co2O4H2 rings.

Hydrogen Bonded 3D Molecular Self Assembly Constructed from [(Ni(nicotinamide)_2(thiocyanate)_2(H_2O)_2] Complex Showing Spin Canted Anti-ferromagnetic Character

A new three-dimensional nickel（Ⅱ） hydrogen-bonded molecular self assembly containing [（Ni（nicotinamide）2（thiocyanate）2（H2O）2] complex has been synthesized and characterized by single-crystal X-ray diffraction,FTIR spectroscopy,thermal analysis and magnetic measurements.Structural analysis reveals that the complex crystallizes in triclinic space group P1（crystal data a = 7.5574,b = 8.2683,c = 9.0056 A,α = 73.010,β = 69.698,γ = 66.51） and exhibits a distorted octahedral coordination sphere.Most interesting point in its structure is the involvement of sulphur atom of thiocyanate moiety in the trifurcated hydrogen bonding to build up the hydrogen-bonded self assembly.The magnetic behavior as determined by squid magnetometer（2~300 K temp.range） reveals dominating antiferromagnetic interaction followed by spin canting behavior below 20 K.

New Synthesis and Molecular Structure of 2-(4'-Methoxyphenyl)-2,4-dithia-1,3,2-diazaphospholidine-5,1'-spirocyclohexane

The novel spirophosphoroheterocycle (C14H19N2OPS2, Mr = 326.40) was synthesized by the treatment of Lawesson磗 reagent with amino cyclohexanenitrile, and its crystal structure was analyzed by X-ray diffraction method. The title compound is of monoclinic, space group P21/n with a = 14.296(4), b = 11.028(3), c = 21.715(6) ? ?= 101.823(6), V = 3351.1(2) 3, Z = 8, Dc = 1.294 g/cm3, ?= 0.71073 ? (MoK? = 0.410 mm―1 and F(000) = 1376. The structure was refined to R = 0.0521 and wR = 0.0744 for 5909 observed reflections with I > 2(I). X-ray diffraction analysis reveals that there are three rings in the molecule. The saturated 6-membered ring presents in chair conformation and the 5-membered phosphoroheterocycle is planar. The molecules are found to exist in couples. The existence of d-p?bonds between P and two N atoms and the intermolecular hydrogen bonds are found as well.

Three New Coordination Polymers Constructed by Adjusting the Angles of Pyridyl or Imidazolyl-based Synthons： Structures and Solid UV-vis Properties

Three new 2D metal-organic frameworks, [M（BIDPE）2（bdc）2]n（M = Co for 1, Ni for 2） and [Ni（PIDPE）2（H2O）2（bdc）]n（3）（BIDPE = 4,4A-bis（imidazol-1-yl） diphenyl ether, PIDPE =4-（pyridyl）-4A-（imidazol-1-yl） diphenyl ether, bdc2- = 1,3-benzenedicarboxylate）, were characterized by single-crystal X-ray diffraction, elemental analysis, PXRD, IR spectroscopy and TGA analysis.Complex 1 crystallizes in monoclinic, space group P21/n, with a = 9.1568（12）, b = 16.943（2）, c =15.441（2） A, β = 104.049（2）°, V = 2323.9（5） A^3, Dc = 1.420 g/cm^3, Mr = 993.83, F（000） = 1026, μ =0.440 mm-（-1） and Z = 2. Complex 2 crystallizes in monoclinic, space group P21/n, with a =9.1395（17）, b = 17.019（3）, c = 15.473（3） A, β = 104.651（2）°, V = 2328.5（7） A^3, Dc = 1.414 g/cm^3,Mr = 991.58, F（000） = 1024, μ = 0.487 mm^-1, Z = 2. Complex 3 also belongs to the monoclinic system, space group P21/n, with a = 11.4365（16）, b = 18.346（3）, c = 11.7068（17） A, β = 91.022（2）°,V = 2455.9（6） A3, Dc = 1.422 g/cm^3, Mr = 1051.66, F（000） = 1092, μ = 0.468 mm^-1, Z = 2. All complexes 1, 2 and 3 are 2D layer structures constructed from intermolecular hydrogen bonds. In addition, the solid UV-vis properties of complexes 1, 2 and 3 were also studied.

Assembly of Highly Ordered 2D Arrays of Silver-PNIPAM Hybrid Microgels

A strategy was developed for the synthesis of highly ordered 2D arrays of Ag-PNIPAM hybrid microgel. The highly ordered 2D arrays of PNIPAM microgel were prepared by dispersing PNIPAM microgel on a charge-reversible substrate. The microgel spheres self-assembled into a 3D colloidal crystal, and the first 111 plane was fixed in situ onto the substrate as a result of spontaneous charge reversal of the substrate, leaving a high-quality 2D array of PNIPAM microgel. Ag nanoparticles were then synthesized in situ inside the microgel spheres by introduction of Ag＋ ions into the microgel spheres and reduction with sodium borohydride. The resulting 2D arrays are highly ordered. The inter-particle distance in the array can be tuned. In addition, the method allows the synthesis of large size arrays and the use of nonplanar substrate.