Potential Energy Surface-Based Automatic Deduction of Conformational Transition Networks and Its Application on Quantum Mechanical Landscapes of d-Glucose Conformers.
This paper describes our approach that is built upon the potential energy surface (PES)-based conformational analysis. This approach automatically deduces a conformational transition network, called a conformational reaction route map (r-map), by using the Scaled Hypersphere Search of the Anharmonic Downward Distortion Following method (SHS-ADDF). The PES-based conformational search has been achieved by using large ADDF, which makes it possible to trace only low transition state (TS) barriers while restraining bond lengths and structures with high free energy. It automatically performs sampling the minima and TS structures by simply taking into account the mathematical feature of PES without requiring any a priori specification of variable internal coordinates. An obtained r-map is composed of equilibrium (EQ) conformers connected by reaction routes via TS conformers, where all of the reaction routes are already confirmed during the process of the deduction using the intrinsic reaction coordinate (IRC) method. The postcalculation analysis of the deduced r-map is interactively carried out using the RMapViewer software we have developed. This paper presents computational details of the PES-based conformational analysis and its application to d-glucose. The calculations have been performed for an isolated glucose molecule in the gas phase at the RHF/6-31G level. The obtained conformational r-map for α-d-glucose is composed of 201 EQ and 435 TS conformers and that for β-d-glucose is composed of 202 EQ and 371 TS conformers. For the postcalculation analysis of the conformational r-maps by using the RMapViewer software program we have found multiple minimum energy paths (MEPs) between global minima of1C4and4C1chair conformations. The analysis using RMapViewer allows us to confirm the thermodynamic and kinetic predominance of4C1conformations; that is, the potential energy of the global minimum of4C1is lower than that of1C4(thermodynamic predominance) and that the highest energy of those of all the TS structures along a route from4C1to1C4is lower than that of1C4to4C1(kinetic predominance).
Research Organization of Information and Systems (ROIS), Tokyo 105-0001, Japan.|Department of Chemistry, University of Zurich , 8057 Zurich, Switzerland.|National Institute of Informatics (NII), Tokyo 101-8430, Japan.|Institute for Quantum Chemical Exploration (IQCE), Tokyo 108-0022, Japan.
Hiroko
H
Satoh
Software Research Associates Inc., Tokyo 171-8513, Japan.
Tomohiro
T
Oda
Center for the Promotion of Interdisciplinary Education and Research, Kyoto University , Kyoto 606-8501, Japan.
Kumiyo
K
Nakakoji
National Institute of Informatics (NII), Tokyo 101-8430, Japan.
Takeaki
T
Uno
Department of Mathematical Informatics, University of Tokyo , Tokyo 113-8654, Japan.
Hiroaki
H
Tanaka
Department of Mathematical Informatics, University of Tokyo , Tokyo 113-8654, Japan.
Satoru
S
Iwata
Institute for Quantum Chemical Exploration (IQCE), Tokyo 108-0022, Japan.|Department of Chemistry, Graduate School of Science, Tohoku University , Sendai 980-8578, Japan.
Koichi
K
Ohno
D005947:Glucose / Q000737:chemistry*; D007700:Kinetics; D008958:Models, Molecular; D008968:Molecular Conformation; D011789:Quantum Theory; D013816:Thermodynamics
D005947:Glucose