10275-62-4Relevant academic research and scientific papers
A perimidine-derived non-kekule triplet diradical
Quast, Helmut,Nuedling, Wolfgang,Klemm, Gerhard,Kirschfeld, Andreas,Neuhaus, Patrik,Sander, Wolfram,Hrovat, David A.,Borden, Weston Thatcher
, p. 4956 - 4961 (2008/12/20)
(Chemical Equation Presented) 6,9-Di(tert-butyl)-1-methyltetrazolo[1,5-a] perimidine (1) has been synthesized from naphthalene in seven steps. The EPR spectra, recorded after irradiation of 1 in a butyronitrile matrix at 77 K (λ = 351 nm) and in Ar and Xe matrixes at 4.6 K (λ ≥ 345 nm), showed a six-line, high-field signal (Δms = ± 1), centered at 3350 G in butyronitrile, along with a half-field signal (Δms = ± 2), which is characteristic for triplets. Simulation of the observed EPR spectra gave values for the zero-field splitting parameters of |D/hcl/ cm-1 = 0.0105, |E/hcl/cm-1 = 0.0014 in butyronitrile and |D/hcl/cm-1 = 0.0107, |ER/hcl/cm-1 = 0.0016 in Ar. These EPR parameters are consistent with the diradical 5,8-di(tert-butyl)-2-(N-methylimino)perimidine-1,3-diyl (32) as source of the EPR spectra. Linearity of the Curie-Weiss plot and UB3LYP and (14/14)CASPT2 calculations of the singlet-triplet energy difference (ΔEST ≈ 8-10 kcal/mol) indicate that the triplet is the ground state of 2, as predicted for such a nondisjoint diradical.
