The concept of an entatic or rack-induced state describes how a protein fold can place a transition metal center in a strained geometric environment. This strain can finely tune the active site’s electronic structure and thus its physical and chemical properties. Beyond bioinorganic chemistry, the entatic state concept has relevance to a multitude of processes in chemistry and materials science. However, entatic states and energetics have only been defined and quantified for a few systems. In this work, a combined experimental and computational approach is developed and used to extend the entatic state description to dozens of Cu-based photosensitizers, a set of molecules widely studied for solar energy conversion, organic light emitting diodes, and photoredox catalysis. Entatic energies determined here are the largest yet determined (~20 kcal/mol) and approach typical chemical driving forces and barriers. Furthermore, the approach outlined here provides a method to decouple steric and electronic influences on the excited state potential energy surfaces and dynamics of transition metal complexes. These insights can guide the design of transition metal complexes with tailored excited state lifetimes and properties, as well as inspire the extension of entatic concepts to catalysis and magnetism.

Quantifying entatic states in photophysical processes: Applications to copper photosensitizers

Macromolecular Chemistry: The Second Century

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ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.