Molecular Dynamics Simulation Study of CIF in Water： Halogen Bonding Interaction in Liquid

Does the halogen bonding interaction co-exist in liquid when it competes with the hydrogen bonding interaction？ The classical molecular dynamics simulations for the solvation properties of CLF molecule in water are performed with the Lennard-Jones plus Coulomb electrostatic potential parameters that are optimized with ab initio interaction energy calculations for the pre-reactive H2O-CLF complex. We find that the halogen bonding interactions occur between O and CL atoms and have the comparable strength and population with respect to the hydrogen bonding interactions of C1...H.

A New Three-dimensional Supramolecular Polymer Built from Non-covalent Bonding Interactions

A new complex, [Ni2（L）4（H2O）8]（1, L1 = 4-（1H-imidazol-4-yl）benzoic acid）, has been hydrothermally prepared and characterized by single-crystal X-ray diffraction, IR spectroscopy, elemental analysis and PXRD. Complex 1 crystallizes in monoclinic, space group P21/c with α = 22.281（2）, b = 7.3959（7）, c = 24.978（3） ？, β = 90.876（10）, V = 4115.6（7） ？3, Z = 8, C20H22N4O8Ni, Mr = 505.13, Dc = 1.630 g/cm3, μ = 1.001 mm-1, S = 1.080, F（000） = 2096, the final R = 0.452 and wR = 0.1152 for 9380 observed reflections （I 〉 2σ（I））. The result of X-ray diffraction analysis revealed three different kinds of Ni（II） centre mononuclear molecules in the asymmetric unit. The independent mononuclear units are bridged to form a three-dimensional supramolecular polymer by extensive hydrogen bonds and C–H… non-covalent bonding interactions.

Machine learning with active pharmaceutical ingredient/polymer interaction mechanism:Prediction for complex phase behaviors of pharmaceuticals and formulations

The high throughput prediction of the thermodynamic phase behavior of active pharmaceutical ingredients(APIs)with pharmaceutically relevant excipients remains a major scientific challenge in the screening of pharmaceutical formulations.In this work,a developed machine-learning model efficiently predicts the solubility of APIs in polymers by learning the phase equilibrium principle and using a few molecular descriptors.Under the few-shot learning framework,thermodynamic theory(perturbed-chain statistical associating fluid theory)was used for data augmentation,and computational chemistry was applied for molecular descriptors'screening.The results showed that the developed machine-learning model can predict the API-polymer phase diagram accurately,broaden the solubility data of APIs in polymers,and reproduce the relationship between API solubility and the interaction mechanisms between API and polymer successfully,which provided efficient guidance for the development of pharmaceutical formulations.

Quantum-chemical investigation on hydrogen bonding interaction of hydrogen fluoride dimer at various mutual orientations

Hydrogen bonding interaction in hydrogen fluoride dimer has been investigated by quan- tum-chemical calculation with 6-311G^(**) basis set at various mutual orientations.Atomic charges and charge transfer have been calculated by means of potential-derived method,and decomposition of hydro- gen bonding interaction has been executed.The calculation results show that there is a variation range for the energy-stable orientations,the charge transfer in the range presents maximum value,and the charge transfer interaction plays a decisive role in the hydrogen bonding.

Bondings and Interactions in Fe-CO:Pairing versus Unpairing Mechanism

Four micro states of Fe-CO with 3d(sigma)-4s and 3d(delta)-3d(delta) electrons spin-paired or unpaired are examined to investigate the influence of pairing versus unpairing mechanism upon the bondings and interactions in Fe-CO. The calculation results show that the Fe-CO bondings and interactions are determined by a balance between the bonding stabilization and the exchange stabilization with or without 3d(sigma)-4s electron spin-pairing. The 3d(delta)-3d(delta) electron spin-pairing versus unpairing has a surprising large effect on the Fe-CO bonding properties, even though the 3d(delta) orbitals are usually considered as being nonbonding.

Responsive organic room-temperature phosphorescence materials for spatial-time-resolved anti-counterfeiting

Stimulus-responsive room-temperature phosphorescence(RTP)materials have gained significant attention for their important optoelectronic application prospects.However,the fabrication strategy and underlying mechanism of stimulus-responsive RTP materials remain less explored.Herein,we present a reliable strategy for achieving pH-responsive RTP materials by integrating poly(vinyl alcohol)(PVA)with carboxylic acid or amino group functionalized terpyridine(Tpy)derivatives.The resulting Tpy derivativesbased RTP materials displayed reversible changes in emission color,intensity,and lifetime of both prompt and delayed emission.Notably,the RTP emission undergoes a significant diminish upon exposure to acid due to the protonation of Tpy units.Taking advantage of the decent RTP emission and pH-responsiveness of these RTP films,a spatial-time-resolved anti-counterfeiting application is demonstrated as a proof-ofconcept for largely enhancing the security level.This study not only provides new prospects for developing smart RTP materials but also promotes the advancement of optical anti-counterfeiting applications.

Transition metal coordination polymers with flexible dicarboxylate ligand:Synthesis,characterization,and photoluminescence property

Under solvothermal conditions,six new coordination polymers(CPs)[Mn(L)(phen)(H_(2)O)]_(n)(1),[Co(L)(phen)(H_(2)O)]_(n)(2),[Cu(L)(phen)(H_(2)O)]_(n)(3),[Zn_(2)(L)_(2)(phen)2(H_(2)O)]_(n)(4),[Zn(L)(phen)]_(n)(5),and[Cd(L)(phen)2]_(n)(6)were synthesized by reactions of dicarboxylate ligand 2,2'-(1,2-phenylenebis(methylene))bis(sulfanediyl)dinobutyric acid(H_(2)L)and 1,10-phenanthroline(phen)with the corresponding metal salts.Complexes 1-6 have been structurally characterized by single-crystal X-ray diffraction analyses,elemental analysis,IR,thermogravimetric analysis,and powder X-ray diffraction.The structures of 1-6 are 1D chains,which are further connected by hydrogen bonding interac-tions to form 3D supramolecular structures.Among them,1 and 2 are isomorphic with L2-of syn-conformation,while L2-shows anti-conformation in 3-6.In addition,the solid-state photoluminescence property of 4-6 was investigated.

THROUGH—SPACE AND THROUGH—BOND INTERACTIONS IN 1,5-CYCLOOCTADIYNE; THE ASSIGNMENT OF ITS PHOTOELECTRON SPECTRA

The through--space and through--bond interactions in 1, 5 -- Cyclooctadiyne are studied. It is shown, with the assistance of improved MS--X_α method, that the through- space interactions decrease with the distance of the orbitals, and both through--space and through--bond interactions of 1, 5- Cyclooctadiyne are sizable but those two interactions oppose each other causing the net splitting to be small for π_z orbital. The calculated ionization potentials are in good agreement with the experiment of photoelectron spectra.

Study on the Hydrogen Bond Interaction Between Soy Protein Isolate and Glycerol Using Two-Dimensional Correlation Fourier-Transform Infrared Spectroscopy

A series of soy protein isolate(SPI)films plasticized by glycerol(Gly)were studied using attenuated total reflectance-Fourier transform infrared spectroscopy(ATR/FTIR).Perturbation-correlation movingwindow two-dimensional(PCMW2D)and two-dimensional correlation(2DCOS)analyses were applied to the amideⅠband and thus the hydrogen bond interaction between SPI and Gly was systematically investigated.When Gly concentrations were in the range 0~35%,the hydrogen bond amongβ-sheets was replaced by the one between SPI chain and Gly molecule,which caused these protein chains being changed toα-helix.However,the transformation ofβ-sheet toα-helix was saturated and both of them tend to change to random coil when Gly concentrations were in the range 35%~60%.

SYNTHESIS OF MONODISPERSE HOLLOW POLYMER MICROSPHERES WITH FUNCTIONAL GROUPS BY DISTILLATION PRECIPITATION POLYMERIZATION

Monodisperse hollow polymer microspheres having various functional groups on the shell-layer, such as carboxylic acid, pyridyl and amide, were prepared by two-stage distillation precipitation polymerization in neat acetonitrile in the absence of any stabilizer or additive, during which monodisperse poly（methacrylic acid） （PMAA） afforded from the first-stage polymerization was utilized as the seeds for the second-stage polymerization. The shell layer with different functional groups was formed during the second-stage copolymerization of either divinylbenzene （DVB） or ethyleneglycol dimethacrylate （EGDMA） as crosslinker and the functional comonomers, in which the hydrogen-bonding interaction between the carboxylic acid group of PMAA core and the functional groups of the corresponding comonomers, including carboxylic acid, amide and pyridyl, played an essential role for the formation of monodisperse core-shell functional microspheres. The hollow polymer microspheres were then developed after the subsequent removal of PMAA cores by dissolution in ethanol under basic condition. Transmission electron microscopy （TEM） and scanning electron microscopy （SEM） were used to determine the morphology of the resultant PMAA core, functional core-shell microspheres and the corresponding hollow polymer microspheres with different functional groups. FT-IR spectra confirmed the successful incorporation of the various functional groups on the shell layer of the hollow polymer microspheres.

Syntheses and Crystal Structures of Two New Supramolecular Architectures Constructed from the Main Group Metal Chloride and Protonated 2-(3-Pyridyl)benzimidazole

The reactions of SbCl3 and HgCl2 with 2-（3-pyridyl）benzimidazole （PyBIm） in solution acidified with HCl have been investigated. The PyBIm ligands are protonated into 2-（3-pyridinio）benzimidazolium （H2PyBIm） cations and the corresponding metal ions are bonded with chloride atoms into coordination anions, forming two new coordination compounds, namely, （H2PyBIm）（SbCl5） 1 and （H2PyBIm）2（Hg2Cl8） 2. Both compounds were characterized by X-ray crystallography. Crystal data for 1： triclinic, space group P1^- with a = 5.7030（7）, b = 9.0625（11）, c = 16.5929（18） A, α = 91.808（7）°, β = 93.234（6）, γ = 99.216（7）°, C12H11N3SbCl5, Mr = 496.24, V = 844.44（17） A^3, Z = 2, Dc = 1.952 g/cm^3, μ（MoKα） = 2.419 mm^-1, F（000） = 480, the final R = 0.0496 and wR = 0.1382 for 3433 observed reflections （I 〉 2σ（I））. Crystal data for 2： monoclinic, space group P21/c with a = 7.8061（5）, b = 15.8127（9）, c = 12.2435（9） , β = 91.955（4）o, C24H22N6Hg2Cl8, Mr = 1079.26, V = 1510.40（17） 3, Z = 2, Dc = 2.373 g/cm3, μ（MoKα） = 10.889 mm-1, F（000） = 1008, the final R = 0.0293 and wR = 0.0562 for 2854 observed reflections （I 〉 2σ（I））. X-ray diffraction analysis reveals that the antimony（III） is five-coordinated, exhibiting a slightly distorted square-pyramidal coordination geometry; while in 2, a dimeric [Hg2Cl8]^4-anion consists of two trigonal bipyramids sharing two common edges. The organic cations and coordination anions are connected into a one-dimensional belt and a two-dimensional sheet through N-H···Cl hydrogen bonding interactions in compounds 1 and 2, respectively; both are further aggregated into 3D frameworks by strong π-π contacts.

Synthesis and Crystal Structure of a Two-dimensional Cadmium Complex Based on Terephthalate and 1-Methyl-2,2'-bibenzimidazole

The title complex, [Cd（MeHbibzim）（1,4-bdc）]n （1, MelToibzim = 1-methyl-2,2＇- bibenzimidazole, 1,4-bdc = terephthalate）, was synthesized with hydrothermal reactions. The compound crystallizes in monoclinic, space group C2/c with a = 9.822（4）, b = 18.510（7）, c = 22.372（9） A, β = 98.359（6）°, C23H16CdN4O4, Mr = 524.81, V= 4024（3） A3, Z = 8, Dc. = 1.733 g/cm3, μ（MoKa） = 1.126 mm-1, F（000） = 2096, the final R = 0.0597 and wR = 0.1374 for 3906 observed reflections （1 〉 2σ（I））. X-ray diffraction analysis reveals that the Cd atom is coordinated by two nitrogen atoms from the chelating MeHbibzim and three carboxyl oxygen atoms from three terephthalate ligands, thus forming a distorted square pyramidal coordination sphere, [CdN2O3]. Every two Cd atoms are linked together via two carboxyl groups into a dinuclear unit with Cd...Cd separation of 3.806（4） A. The dinuclear building units are linked by terephthalate ligands into two-dimensional layers, which are further aggregated into a 3D framework via hydrogen bonding interactions.

Two Three-dimensional Supramolecular Polymer Built from Mixed N-Donor and Carboxylate Ligands

Two new complexes, [Mn（L）（mmbda）（H_2O）]（1） and [Co（L）（btc）（H_2O）]·H_2O（2）, were synthesized by reacting the corresponding metal（Ⅱ） salts with rigid ligand 1,4-di（1Himidazol-4-yl）benzene（L） and two different carboxylic acids of 5-methylisophthalic acid（H_2mmbda） and 1,2,4-benzenetricarboxylic acid（H_3btc）, respectively. The structures of the complexes were characterized by single-crystal X-ray diffraction, IR spectroscopy, elemental analysis and PXRD. Complex 1 crystallizes in triclinic, space group P1 with a = 6.9436（4）, b = 9.7306（6）, c = 15.5302（10） ？, α = 73.7430（10）, β = 85.1010（10）, γ = 70.0360（10）o, V = 946.75（10） ？~3, Z = 2, C_（21）H_（20）N_4O_5 Mn, M_r = 463.33, D_c = 1.618 g/cm^3, μ = 0.742-1, S = 1.002, F（000） = 474, the final R = 0.0285 and wR = 0.0600 for 4328 observed reflections（I 〉 2σ（I））. Complex 2 crystallizes in monoclinic, space group P2_1/n with a = 12.5216（12）, b = 7.3312（8）, c = 22.510（2） ？, β = 93.104（2）o, V = 2063.3（4） ？~3, Z = 4, C_（21）H_（18）N_4O_8Co, M_r = 513.31, D_c = 1.646 g/cm^3, μ = 0.892^（-1） mm, S = 1.096, F（000） = 1044, the final R = 0.0673 and wR = 0.1780 for 3594 observed reflections（I 〉 2σ（I））. Both of complexes are one-dimensional（1D） chain structures and rich hydrogen bonds extend such 1D chains to form three-dimensional（3D） supramolecular polymers.

Solvent Effects on Spectral Property and Dipole Moment of the Lowest Excited State of Coumarin 343 Dye

Steady-state absorption and fluorescence spectra, and time-resolved fluorescence spectra of coumarin 343 （C343） were measured in different solvents. The effect of the solvent on the spectral properties and dipole moment of the lowest excited state of C343 were investigated. It was found that the absorption and fluorescence spectra red-shifted slightly and strongly with increasing solvent polarity, respectively, because the charge distribution of the excited state leaded to the increasing difference between the absorption and fluorescence spectra with increasing solvent polarity. The dipole moment of the lowest excited state of C343 was determined from solvatochromic measurements and the quantum chemical calculation, and the results obtained from these two methods were fully consistent. Investigations of the time-resolved fluorescence of C343 in different solvents indicated that the fluorescence lifetimes increased nearly linearly with 4.45 ns in water. This can be ascribed between C343 and hydrogen donating increasing solvent polarity from 3.09 ns in toluene to to the intermolecular hydrogen bonding interactions solvents

Synthesis and Crystal Structure of 3-Benzyl-6-trichloromethyl-[1,2,4] triazolo[3,4-b][1,3,4]thiadiazole

The title compound 3-benzyl-6-trichloromethyl-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazole I （C11HTC13N4S, Mr = 333.62） has been synthesized, and its structure was determined by elemental analyses, IR, ^1H NMR, ^13C NMR, and X-ray diffractions. The crystal is of triclinic, space group P1^-, with a = 5.898（3）, b = 10.510（4）, c = 11.580（5） A, α = 74.936（7）, β= 75.476（7）, γ = 79.647（7）°, V= 665.9（5）/A^3, F（000） = 336, Z= 2, Dc = 1.664 g/cm^3, 2 = 0.71073A, p = 0.834 mm^-1, the final R = 0.0605 and wR = 0.0900. The secondary bonding interactions （SBIs） S…N and π-π stacking interactions are found in the crystal structure and they link the molecules into a three-dimensional network.

Synthesis and Crystal Structure of a Cobalt(Ⅱ)Complex Based on 2,2-Bibenzimidazole and N,N-bis(phosphonomethyl)aminoacetic Acid

The title complex, [Co2（bibzim）（H2bibzim）4]·Co2（H2bibzim）2（Hbibzim）（HL）]2- 2H2O （1） （HEbibzim = 2,2＇-bibenzimidazole, H5L = N,N-bis（phosphonomethyl）aminoacetic acid （HO2CCH2N（CH2PO3H2）2））, was synthesized with hydrothermal reactions. The compound crystallizes in triclinic, space group P1 with a = 13.71020（10）, b = 14.9165（5）, c = 20.9924（5） A, a = 86.344（9）, β = 71.214（8）, γ = 73.757（7）°, C162HI24Co6N46O18P4, Mr = 3478.52, V = 3900.55（16） A3, Z = 2, Dc = 1.482 g/cm3,μ（MoKa） = 0.747 mm^-1, F（000） = 1784, the final R = 0.0777 and wR = 0.2091 for 13598 observed reflections （I 〉 2σ（I））. X-ray diffraction analysis reveals that there are three crystallographically independent Co（II） atoms in the complex. The complex consists of binuclear coordination cation, binuclear coordination anion, as well as lattice water molecules, which further aggregate into a 3D framework via hydrogen bonding as well as π-π interactions.

Synthesis and Crystal Structure of an Infinite 1D Zigzag Chain Compound (dimbH^+)(ClO_4^-) and Its Comparison with (dimb)2H_2O (dimb = 1,3-Di(imidazol-1-ylmethyl)-5-methylbenzene)

A new imidazolium compound, C15H17N4ClO4, was prepared from a flexible bidentate ligand of 1,3-di(imidazol-1-ylmethyl)-5-methylbenzene, and characterized by X-ray analysis. It is of orthorhombic, space group Pnma with a = 8.182(2), b = 12.874(3), c = 15.611(4) ? V = 1644.4(7) 3, Dc = 1.425 g/cm3, Z = 4, Mr = 352.78, m(MoKa) = 0.944 mm-1, F(000) = 736, S = 1.036, the final R = 0.0521 and wR = 0.1187 for 1128 observed reflections (I > 2s(I)). An infinite one-dimensional zigzag chain is formed by NH…N hydrogen bonding interactions between the imidazolium salt cations.

Syntheses and Structures of Two Complexes Based on Mixing Carboxylate Ligands and Imidazole-containing Ligands

Two novel complexes, [Zn（L2-1）（L2）]（1） and [Ni（L2-3）（L4）·2H2O]（2）, have been synthesized by solvothermal reactions in different solvents through mixing the carboxylate ligand, imidazole-containing ligand and the metal salt. Compound 1 crystallizes in monoclinic, space group P21/c with a = 9.21400（15）, b = 18.1172（3）, c = 15.7669（2） A, β = 91.1769（13）o, C30H26N4O4 Zn, Mr = 571.92, V = 2631.44（7） A3, Z = 4, Dc = 1.444 g·cm-3, μ = 1.659 mm-1, F（000） = 1184, λ（Cu Kα） = 1.54178 A, the final R = 0.048, w R = 0.1442 and S = 1.139. Compound 2 crystallizes in triclinic, space group P1 with a = 7.0664（3）, b = 9.5265（4）, c = 12.8861（6） A, α = 74.066（4）, β = 87.408（3）, γ = 83.591（3）o, C34H32N6O6S2 Ni, Mr = 743.49, V = 828.83（6） A3, Z = 1, Dc = 1.490 g·cm-3, μ = 2.490 mm-1, F（000） = 386, λ（CuK α） = 1.54178 A, the final R = 0.0315, w R = 0.0861 and S = 1.022. Complex 1 is the 1D chain which is linked by C–H···O hydrogen bonding interactions to form a 2D supramolecular architecture. Meanwhile, complex 2 is a 2D（4,4） network with the ABCABC stacking mode and then generates a 3D supramolecular architecture through C–H···N and O–H···O hydrogen bonding interactions.

Synthesis and Crystal Structure of a New Zn(Ⅱ) Complex Exhibiting Strong Luminescence

The title complex,[Zn（ip）2（H2O）2][ZnCl4]·H2O·2DMF 1（ip=imidazo[4,5-f][1,10] phenanthroline）,has been synthesized via the slow evaporation of concentrated reaction solution at room temperature.It was characterized by single-crystal X-ray diffraction.Crystal data for C32H36Cl4N10O5Zn2：white prism,0.17mm×0.15mm×0.10mm,monoclinic,space group P2/c,a=11.928（8）,b=9.868（6）,c=16.520（11）,β=104.879（12）°,V=1879（2）3,Z=2,Mr=913.25,Dc=1.614 g/cm3,F（000）=932,μ=1.616 mm-1,λ（MoKα）=0.71073,GOOF=1.045,R=0.0710 and wR=0.1755 for 3055 observed reflections with I 〉 2σ（I）. X-ray diffraction study reveals that the title complex has an interesting 3D architecture via hydrogen bonding interactions and π-π interactions. The IR, TGA, XRD and luminescent properties of complex 1 were also studied.

Cellulose Solubility in Deep Eutectic Solvents:Inspecting Quantitative Hydrogen-Bonding Analysis

According to the Kamlet-Abraham-Taft(KAT)polarity parameters(α,β,π*),polymers and solvents can be categorized as hydrogen-bond(H-bond)acidic(α>β)or H-bond basic(α<β).Recently,we proposed a quantitative hydrogen bonding(QHB)analysis to predict the solubility of polymers in ionic liquids(ILs)using the product ofΔαΔβ<0 as an indicator,whereΔαis the difference between the H-bond acidic parameters of the polymer and IL,andΔβis the difference in their basicity,while the prerequisite of the“complementary”principle(i.e.,that one component is H-bond acidic and the other is basic)is satisfied.Here,the applicability of QHB analysis was first confirmed by testing the solubilities of carefully chosen polymer/deep eutectic solvent(DES)pairs,as the DESs were eutectic mixtures dominated by hydrogen bonding interactions.Then,our attention focused on the solubility of cellulose in DESs.Our testing results as well as the typical published results were summarized,which indicate that the potential DESs for cellulose dissolution and regeneration must be of the H-bond basic type because the“complementary”principle should be satisfied as a prerequisite.However,the H-bond basic DESs investigated in this study do not show the superior solubility of cellulose that has been commonly observed for H-bond basic ILs,even if the criterion ofΔαΔβ<0 is satisfied for both DESs and ILs.Possible reasons for this discrepancy are given to understand the varying effectiveness in cellulose dissolution for H-bond basic DESs and ILs.