2,3,5,6-Tetrafluorophenylnitren-4-yl: A Quartet-Ground-State Nitrene Radical

Abstract

Elements of a carbene and a nitrene are linked by a common delocalized π electron in the molecule described here (see picture). The organic high‐spin molecule with a quartet ground state could be photochemically generated and spectroscopically characterized in an argon matrix at 3 K.

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

“…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.…”

EPR spectroscopic and computational characterization of the 2‐dehydro‐m‐xylylene and 4‐dehydro‐m‐xylylene triradicals

“…Triradicals of the σσπ type have been realized as (fluorinated) dehydrophenylnitrenes 10–12 (Chart ) . Phenylnitrene 13 is well known to have a 3 A 2 ground state dominated by the electronic configuration (8b 2 ) 1 (3b 1 ) 1 , whereas the 1 A 2 open‐shell singlet state with the same orbital occupation pattern lies 15–16 kcal/mol higher in energy .…”

“…[51] Triradicals of the ssp type have been realized as (fluorinated) dehydrophenylnitrenes 10-12 (Chart 2). [59][60][61][62][63] Phenylnitrene 13 is well known to have a 3 A 2 ground state dominated by the electronic configuration (8b 2 ) 1 (3b 1 ) 1 , whereas the 1 A 2 open-shell singlet state with the same orbital occupation pattern lies 15-16 kcal/mol higher in energy. [64,65] The 8b 2 orbital is largely localized on the nitrogen atom, whereas the 3b 1 orbital closely resembles the singly occupied molecular orbital of the benzyl radical.…”

Chemistry of phosphorus ylides 31: Reaction of azidocoumarin with active phosphonium ylides, synthesis and antitumour activities of chromenones

“…The present study reports on simple and efficient approaches for the synthesis of new phosphorus derivatives of triazol-, triazepin-, aziridin-, and free phosphorus triazepin chromenone derivatives, especially azepines which rare class of highly strained compounds. 49,50 Many of the new compounds revealed pronounced in vitro antitumour activities when tested against human MCF-7 and HEPG2 carcinoma cell lines. The most promising result against breast carcinoma (MCF-7) was recorded by the phosphanylidene-triazolyl chromenone 3.…”