Chirality: The Backbone of Chemistry as a Natural Science

Josep M Ribó

doi:10.3390/sym12121982

Abstract

Chemistry as a natural science occupies the length and temporal scales ranging between the formation of atoms and molecules as quasi-classical objects, and the formation of proto-life systems showing catalytic synthesis, replication, and the capacity for Darwinian evolution. The role of chiral dissymmetry in the chemical evolution toward life is manifested in how the increase of chemical complexity, from atoms and molecules to complex open systems, accompanies the emergence of biological homochirality toward life. Chemistry should express chirality not only as molecular structural dissymmetry that at the present is described in chemical curricula by quite effective pedagogical arguments, but also as a cosmological phenomenon. This relates to a necessarily better understanding of the boundaries of chemistry with physics and biology.

Highlights

IntroductionCosmological evolution toward the actual world of classical objects passes through many hierarchical stages of increasing complexity
Cosmological evolution toward the actual world of classical objects passes through many hierarchical stages of increasing complexity, which implies two symmetry violations (time and charge parity (CP)) and several symmetry breakdowns
As pointed out by Barron [3], “symmetry breaking” is a process leading to a symmetry inferior to that of the initial Hamiltonian but “symmetry violation” defines a process that does not fulfill the physics symmetry conservation theorems [4]

Summary

Introduction

Cosmological evolution toward the actual world of classical objects passes through many hierarchical stages of increasing complexity Dissymmetry of Molecules: Chemists, for example, synthetic chemists working with solutions, use the term “chirality” to refer to the molecular species as defined by a chiral point group [30] This leads to an incomplete description for isotropic sets of a very large number of units: liquids and solutions of achiral compounds, racemates, enantiopure compounds, and scalemic mixtures. Chemistry as a natural science is concerned with the study of classical and quasi-classical objects, chemical methodology is freed of any metaphysical considerations [33] This explains, in our opinion, the general reluctance of chemists to work on topics related to the origin of life that are suspected of being parascientific topics.

Chemical Chirality

Molecules

Emergence of Biological Homochirality

Concluding Remarks