[1,2,5]Selenadiazolo[3,4‐<i>b</i>]pyrazines: Synthesis from 3,4‐Diamino‐1,2,5‐selenadiazole and Generation of Persistent Radical Anions

Abstract

Abstract Previously unknown 3,4‐diamino‐1,2,5‐selenadiazole ( 6 ) was prepared by hydrolysis of [1,2,5]selenadiazolo[3,4‐ c ][1,2,5]selenadiazole ( 7b ) and used in synthesis of novel 1,2,5‐selenadiazolo[3,4‐ b ]pyrazines by the Koerner–Hinsberg reaction covering the parent compound 4 and its substituted derivatives 5a – g . The compounds synthesized were characterized by solution and solid‐state 77 Se NMR, and 6 , 5‐Ph and 5,6‐Me 2 [1,2,5]selenadiazolo[3,4‐ b ]pyrazines ( 5a , g , respectively) by X‐ray diffraction. Electrochemical reduction of 5,6‐R 2 [1,2,5]selenadiazolo[3,4‐ b ]pyrazines 5c , g (R = Ph, Me) into novel persistent radical anions (RAs) was studied by cyclic voltammetry and the RAs [ 5c ] – and [ 5g ] – were characterized by EPR spectroscopy combined with DFT calculations.