Permethylated Salts and Radicals Derived from Azo <i>peri‐</i>Naphthalenes

Abstract

Abstract By careful choice of reaction conditions 1‐methylnaphtho[1,8‐ de ]‐1,2,3‐triazine and 1,3‐dimethylnaphtho[1,8‐ de ]‐1,2,3‐triazinium triflate are readily prepared by the alkylation of 1 H ‐naphtho[1,8‐ de ]‐1,2,3‐triazine. The electronic spectra for these bathochromically shifted dyes are reported for a range of solvents as are their vibrational spectra and theoretical structures from density functional theory, B3LYP/6‐311++G**. The 15 N substitution into the middle nitrogen atom allows for the identification of strong azine bands in the IR and Raman spectra as well as in the 15 N NMR spectrum. X‐ray crystallography is used to characterize the solid‐state structures of two of these new triazine derivatives and these structures are used to benchmark the theoretical and spectroscopic discussions. The corresponding 1,3‐dimethyltriazinium radical is prepared and characterized by cyclic voltammetry, spectroelectrochemistry, and EPR spectroscopy. Unlike the related transient 1,2,4‐triazene radicals, the 1,3‐dimethyl‐1,2,3‐naphthotriazyl radical is markedly more stable.