The helix surface of sugar ring for tetrahydrofuran

Abstract

The present calculations of three geometry conformation for tetrahydrofuran (THF, C 4 H 8 O) using density functional theory lead to the energy level sequence E (C 1 ) < E (C s ) < E (C 2v ), where, both the geometry symmetry C 2v and C s are probably a transition structure. The C 1 symmetry is the equilibrium conformation, for its energy is the lowest one and it is only possible without the negative harmonic frequency. In C 1 conformation, the 4 of carbon atoms C and oxygen atom O constitute a curved surface or the helix surface. The tetrahydrofuran molecule can be as a simple prototype of deoxyribose and has been reviving a quite deal of interest in radiation damage research. It is well known that the sugar ring of deoxyribose is considered as a plane in most of the references. If the equilibrium conformation of THF is C 1 symmetry with the helix surface, and for the same reason, the sugar ring of deoxyribose would be also the helix surface; this probably causes the double helix of DNA. It is hardly believed that the sugar ring is a plane in deoxyribose.