Electron-Hole Correlation as Unambiguous and Universal Classification for the Nature of Low-Lying ππ* States of Nitrogen Heterocycles

Marvin Hoffmann; Stefanie A Mewes; Sonja Wieland; Christoph Popp; Andreas Dreuw

doi:10.1021/acs.jpclett.9b02522

Electron-Hole Correlation as Unambiguous and Universal Classification for the Nature of Low-Lying ππ* States of Nitrogen Heterocycles

J Phys Chem Lett. 2019 Oct 17;10(20):6112-6117. doi: 10.1021/acs.jpclett.9b02522. Epub 2019 Oct 1.

Authors

Marvin Hoffmann¹, Stefanie A Mewes², Sonja Wieland¹, Christoph Popp¹, Andreas Dreuw¹

Affiliations

¹ Interdisciplinary Center for Scientific Computing , Ruprecht-Karls University , Im Neuenheimer Feld 205A , D-69120 Heidelberg , Germany.
² Centre for Theoretical Chemistry and Physics, New Zealand Institute for Advanced Studies , Massey University Albany , Private Bag 102904, Auckland 0632 , New Zealand.

PMID: 31573203
DOI: 10.1021/acs.jpclett.9b02522

Abstract

The ¹L_a and ¹L_b classification of electronically excited states of cata-condensed hydrocarbons proposed by Platt in 1949 ( Platt , J. R. J. Chem. Phys. 1949 , 17 , 484 ) is challenged by investigating a series of N-heteronaphthalenes and comparison of their low-lying ππ* excited states to those of naphthalene. The breakdown of Platt's classification scheme for N-heterocycles is highlighted, and a reliable and versatile alternative using exciton analyses is presented. The strength of electron-hole correlation turns out to be the most reliable distinguishing feature, and thus, an alternative nomenclature of ¹L_w (weakly correlated) and ¹L_s (strongly correlated) is proposed. Furthermore, fundamental guidelines for their property modulation through N-atom substitution patterns are discussed.