Three end-capped para-benzoyl calixarene bonded silica gel stationary phases are prepared and characterized by elemental analysis, infrared spectroscopy, and thermal analysis. The comparison and selectivity of these phases are investigated by using PAHs, disubstituted benezene, and naphthalene positional isomers as probes. Possible separation mechanism based on the different interactions betwee...

Large changes in heat capacity (deltaCp) have long been regarded as the characteristic thermodynamic signature of hydrophobic interactions. However, similar effects arise quite generally in order-disorder transitions in homogeneous systems, particularly those comprising hydrogen-bonded networks, and this may have significance for our understanding of protein folding and other biomolecular proce...

The Cl- -C6H5CH3*Ar, Cl- -C6H5NH2*Ar, and Cl- -C6H5OH*Ar anion complexes are investigated using infrared photodissociation spectroscopy and ab initio calculations at the MP2/aug-cc-pVDZ level. The results indicate that for Cl- -C6H5NH2 and Cl- -C6H5OH, the Cl- anion is attached to the substituent group by a single near-linear hydrogen bond. For Cl--C6H5CH3, the Cl- is attached to an ortho-hydro...

To determine the non-bonded interaction energies between Naphthalene and B12N12 Nano ring in different orientations and distances, geometry of molecules with B3LYP method and 6-31g* basis set optimized. Also reactivity and stability of Naphthalene alone and in the presence B12N12 Nano ring checked. Then calculated the NBO, NMR, FREQ, NICS and muliken charge of Naphthalene atoms alone and in the...

To determine the non-bonded interaction energies between Naphthalene and B12N12 Nano ring in different orientations and distances, geometry of molecules with B3LYP method and 6-31g* basis set optimized. Also reactivity and stability of Naphthalene alone and in the presence B12N12 Nano ring checked. Then calculated the NBO, NMR, FREQ, NICS and muliken charge of Naphthalene atoms alone and in the...

THE CRYSTAL OF THE TITLE COMPOUND [SYSTEMATIC NAME: 4-(benzyl-amino)-benzene-sulfonamide], C(13)H(14)N(2)O(2)S, displays a hydrogen-bonded framework structure. Mol-ecules are doubly N-H⋯O hydrogen bonded to one another via their NH(2) groups and sulfonyl O atoms. These inter-actions generate a hydrogen-bonded ladder structure parallel to the a axis, which contains fused R(2) (2)(8) rings. The N...

The crystal structure of the title compound, C(11)H(13)ClF(3)N(3)O(4)S(3) (systematic name: 6-chloro-2-methyl-3-{[(2,2,2-trifluoro-eth-yl)sulfan-yl]meth-yl}-3,4-dihydro-2H-1,2,4-benzothia-diazine-7-sul-f-on-amide 1,1-diox-ide; CRN: 346-18-9), exhibits a two-dimensional network of hydrogen-bonded mol-ecules parallel to (01). The NH and NH(2) groups act as donor sites and the sulfonyl O atoms as ...

objective: attempts to treat class ii malocclusions without extraction in non-compliant patients have led to utilization of intraoral molar distalizing appliances. the purpose of this study was to investigate dental and skeletal effects of bonded molar distalizer (bmd) which is a simple molar distalizing appliance. materials and methods: sixteen patients (12 girls, four boys) with bilateral hal...

Hydrogen bonds are weak, generally intermolecular bonds, which hold much of soft matter together as well as the condensed phases of water, network liquids, and many ferroelectric crystals. The small mass of hydrogen means that they are inherently quantum mechanical in nature, and effects such as zero-point motion and tunneling must be considered, though all too often these effects are not consi...

HO3-(O2)n clusters are formed by the sequential addition of the hydroxyl radical and O2 molecules to superfluid helium nanodroplets. IR laser spectroscopy in the fundamental OH stretching region reveals the presence of several bands assigned to species as large as n=4. Detailed ab initio calculations are carried out for multiple isomers of cis- and trans-HO3-O2, corresponding to either hydrogen...