We utilized UV resonance Raman (UVRR) measurements and density functional theory (DFT) calculations to relate the AmII'p frequency to the psi angle. The AmII'p frequency shifts by approximately 25 cm(-1) as the psi angle is varied over allowed angles of the Pro peptide bond. The AmII'p frequency does not show any significant dependence on the phi dihedral angle. The conformation sensitivity of ...

The Cambridge Structural Database ( CSD ) contains a large amount of molecular structure data ( bond length, bong angle and torsion angle data.) Much of this data has previously been extracted in histogram form and provided in the Mogul program. Histograms however have several disadvantages e.g. they are not smooth, they depend on bin widths and bin end points. Kernel density estimators do not ...

A combination of simulations and Fourier transform infrared spectroscopy was used to examine the effect of three ionic solutes ~KCl, NaCl, and KSCN!, the polar solute urea, and the osmolyte trimethylamine-N-oxide ~TMAO! on a water structure. The ionic solutes increase the mean water– water H-bond angle in their first hydration shell concomitantly shifting the OH stretching mode to higher freque...

We used the lattice Boltzmann method to study the displacement of a two-dimensional immiscible droplet subject to gravitational forces in a channel. The dynamic behavior of the droplet is shown, and the effects of the contact angle, Bond number ~the ratio of gravitational to surface forces!, droplet size, and density and viscosity ratios of the droplet to the displacing fluid are investigated. ...

In the title mol-ecule, C(28)H(28)F(2)N(2)O(2), the ethene bond exhibits an E conformation and the piperazine ring adopts a chair conformation. The amide-N atom of the piperazine ring is almost planar (bond-angle sum = 358.8°) whereas the other N atom is clearly pyramidal (bond-angle sum = 330.5°). The dihedral angle between the fluoro-benzene rings is 76.36 (17)°. In the crystal, inversion dim...

The structure and energetics of the ring isomers of C(4n+2) (n=3-5) carbon clusters were studied by using coupled-cluster singles and doubles excitation theory to overcome the vast differences existing in the literature. The results obtained in the present study clearly indicate that C(14), C(18), and C(22) carbon rings have bond-length and bond-angle alternated acetylenic minimum energy struct...

In the title compound, C(12)H(10)N(2)O(4)S, the conformation of the N-H bond in the -SO(2)-NH- fragment is syn to the ortho-nitro group in the sulfonyl-benzene ring. The mol-ecule is twisted at the S-N bond, the C-N-S-C torsion angle being -72.83 (15)°. The dihedral angle between the benzene rings is 59.55 (7)°. The amide H atom and the nitro group O atom form an intra-molecular hydrogen bond, ...

In the title mol-ecule, C(29)H(32)N(2)O(3), the piperazine ring has a chair conformation. The amide N atom is almost planar (bond angle sum = 359.5°), whereas the other N atom is clearly pyramidal (bond angle sum = 330.4°). The dihedral angle between the meth-oxy-benzene rings is 81.29 (16)°. In the crystal, mol-ecules are linked by C-H⋯O hydrogen bonds.