The 191st MANA Special Seminar
Motohiro Nishio & Prasanth Jose
| Date | Jan 11, Tuesday |
| Time | 15:30-17:00 |
| Place | Seminar Room #431, 4F, MANA Bldg., Namiki, NIMS |
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15:30-16:15
The CH/π hydrogen bond
Implication in supramolecular chemistry, conformation, and biological science
The CH/π hydrogen bond is the weakest extreme of hydrogen bonds that occurs between a soft acid CH and a soft base π-system. The implication in chemistry includes issues of conformation, crystal packing, and specificity in inclusion compounds. The results obtained by analyzing the Cambridge Structural Database will be reviewed. Recent high-level ab initio MO calculations have provided evidence that folded conformations reported for natural organic compounds is explained in terms of CH/π hydrogen bonds. The implications of CH/π hydrogen bonds in structural biology and rational drug design will be presented.
Speaker
Motohiro Nishio, The CHPI Institute, Japan
Chair
Katsuhiko Ariga, Principal Investigator, MANA, NIMS
16:15-17:00
Microscopic origin of anisotropic scattering patterns in semi-dilute polymer solutions under steady shear flow
Shear flow is ubiquitous in nature such as blood flow in veins. Semidilute polymer solutions are complex systems which show large density fluctuations due to competing intra and inter-chain interactions. Interestingly, crucial experiments established semidilute solutions show anisotropic enhancement of density fluctuations and light scattering (butterfly patterns) under shear flow, contrary to perception. To address this conundrum, we investigated such system using Brownian Dynamics simulations. It was found that the comparable contributions to structure factor from intra- and interchain correlations in an equilibrium semidilute solution are entirely modified by the shear flow. Finally to elucidate microscopic origin, we investigated the single-chain dynamics in the solution, showing for the first time, the real-time molecular behavior of polymer chains under shear flow. This would potentially lead to design of novel polymers with controlled flow rates for diverse applications.
Speaker
Prasanth Jose, School of Basic Science, Indian Institute of Technology, Mandi, India
Chair
Yoshio Bando, MANA COO, MANA, NIMS