Spherical conformational landscape shed new lights on fluxional nature of cyclopentane and its derivatives, confirmed by their Raman spectra

Abstract

A detailed conformational analysis of cyclopentane and its derivatives were performed using DFT ωb97xd/6-311+G(d,p) level of theory. Intrinsic Reaction Coordinate (IRC) computations augmented with frequency computations were used to figure out a way to assemble four pseudorotational platforms into a final hyper-surface which can elaborately describe the vibrational pattern in Raman spectra of five membered ring compounds. The spherical conformational landscape represents two concentric ring coordinates for twisting and bending pathways in cyclopentane and its derivatives. The two ring coordinates work hand-in-hand to support the very intrinsic property of this molecule, its fluxional nature, coded intricately into the D/G band region (1100–1600cm−1) of its Raman spectrum. This fluxional nature seems to cope with almost any rigidity imposed by either temperature or structural restrictions. The same rationale was also used to resolve a hyper-surface for the fused five membered rings, octahydropentalenes. Further investigations are needed to shed light on the so called sugar pucker conformational wheels in DNA, B and A helices.