Dicyanocarbodiimide and Trinitreno‐s‐triazine Generated by Consecutive Photolysis of Triazido‐s‐triazine in a Low‐Temperature Nitrogen Matrix

Abstract

Carbon nitride molecules: Photolysis (λ=266 nm) of triazido‐s‐triazine (C3N12, 1) in a nitrogen matrix at 20 K yielded a succession of reactive species (see scheme), including, in order, an apparent trinitrene, NCN, and a novel C3N4 isomer, dicyanocarbodiimide NCNCNCN.

Matrix isolation and IR spectroscopic characterization of 3,5‐difluoropyridyl‐2,4,6‐trinitrene

“…Although the EPR spectra of organic septet hexaradicals have been reported previously, this is the first high‐quality FTIR spectrum recorded for such a species. In previous studies, the IR identification of septet trinitrenes was based on careful analysis of very small changes in the IR spectra of a complex mixture of many products formed during the photolysis of triazides . The strong IR spectrum of trinitrene 26 obtained in matrices after UV photolysis of 21 indicates that the trinitrene is formed in good yield.…”

“…In the last decade, much attention has been focused on explorations of high‐spin nitrenes as models of single molecular magnets . A number of quartet nitreno radicals, quintet dinitrenes, and several septet trinitrenes have been characterized by electron paramagnetic resonance (EPR) spectroscopy and some of them have been studied using Fourier transform infrared (FTIR) and UV–Vis spectroscopies. Among these spectroscopic methods, only FTIR studies provide complete information about all paramagnetic and diamagnetic products formed during the photolysis of aromatic polyazides, thus allowing one to estimate the yield of high‐spin nitrenes in such reactions.…”

“…Similarly, the photolysis of triazide 17 in solid nitrogen at 20 K resulted in only extremely weak IR bands of septet trinitrene 20 along with strong bands of quintet dinitrene 19 . Trinitrene 20 is photochemically very unstable and readily decomposes to triplet cyanonitrene, NCN, even after short photolysis times.…”

Six-Membered Aromatic Polyazides: Synthesis and Application

“…The first organic septet hexaradical was prepared by the photolysis of 1,3,5-triazido-2,4,6-tricyanobenzene [10]. Later, a great variety of high-spin nitrenes possessing unusual magnetic characteristics were obtained by the photolysis of various 1,3,5-triazidobenzenes, 2,4,6-triazidopyridines, 2,4,6-triazidopyrimidines and 2,4,6-triazido-1,3,5-triazine [11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33]. These studies of high-spin nitrenes opened up new prospects in design of new organic magnetic materials and provided important information about UV-vis, IR and EPR spectra of organic molecules with the ground quintet and septet spin-state.…”

Six‐Membered Heterocycles: Triazines, Tetrazines and Other Polyaza Systems

“…Photolysis of 2-azido-4,6-dichloro-1,3,5-triazine, in a low temperature argon matrix, yields a cyclic carbodiimide containing four nitrogen atoms in a sevenmembered ring [668]. Consecutive photolysis of triazido-1,3,5-triazine, in a low temperature nitrogen matrix, has been studied [669,670]. 2,2,4,6-Tetraphenyldihydro-1,3,5-triazine undergoes photochemical reactions to yield a mixture of six products, among which 2,4,5-triphenylimidazole and 2,4,6-triphenyl-1,3,5-triazine could be identified [671,672].…”