The Movement of Two Parallel Unpaired Electrons in Benzene and Aromatic Compounds

Abstract

Dr. Chun Wang*

This year marks the 200th anniversary of Faraday's discovery of benzene, which is stable compared to other hydrocarbons. As we all know, Faraday made a huge contribution to electromagnetism. Coincidentally, benzene owes its special stability to the ring’s electric current and magnetic field. The oscillating hexagonal structure of benzene proposed by Kekulé 160 years ago is the most reasonable structural formula so far, which can be confirmed by modern infrared spectroscopy of the ring mode. However, the formation of the ring current and magnetic field has not been explained properly up to now. The problem lies in not having a correct understanding of the structure of the double bond.

Nuclear magnetic resonance has long confirmed that a double bond contains two unpaired electrons with parallel spins moving in two π-orbits separated by a covalent σ-bond. Due to thermal vibration, the σ-bonds are constantly stretched and compressed around their equilibrium position. The two π-orbits always revolve the two nearest carbon atoms, causing the π-orbits to shift and create an electric current. The current-induced magnetic field encompasses the benzene ring skeleton, making it stable. This additional magnetic field is a typical hallmark of aromatic stability and can be detected with 1 H-NMR spectroscopy. Various aromatic compounds are precisely associated with π-electrons including lone pairs. This paper will solve an aromatic conundrum that has puzzled the scientific community for more than a hundred years.

HTML PDF