Molecular Structure and Magnetic Parameters of Septet 2,4,6-Trinitrenotoluene

Abstract

Septet 2,4,6-trinitrenotoluene is the major paramagnetic product formed during the photolysis of 2,4,6-triazidotoluene in cryogenic matrices. This trinitrene displays different electron paramagnetic resonance (EPR) spectra in solid argon and in 2-methyltetrahydrofuran (2MTHF) glass, corresponding to septet spin states with the zero-field splitting (ZFS) parameters D(S) = -0.0938 cm(-1), E(S) = -0.0040 cm(-1) and D(S) = -0.0934 cm(-1), E(S) = -0.0015 cm(-1), respectively. Analysis of these parameters shows that the molecular and electronic structure of the septet trinitrene derived from the EPR spectrum in argon is in good agreement with the expectations from DFT calculations. The very small parameter E(S) in 2MTHF glass is explained by significant changes of the spin densities on the three nitrene units due to interactions of the nitrogen atom with surrounding 2MTHF molecules.

EPR Studies on Branched High‐Spin Arylnitrenes

“…Thus, for quintet dinitrene 6, Equations (1) and (2) lead to D Q % 0.207 cm À1 and E Q % 0.033 cm À1 . [7] The latter shows a somewhat larger D S value due to a higher Mulliken spin population on the nitrene units (1 N = 1.566-1.589), and a larger D T value (0.998 cm À1 ) of the corresponding mononitrene. The isomeric dinitrene 7 with D t % 0.91 cm À1 and V = 111.78 should be described by D Q % 0.160 cm À1 and E Q % 0.048 cm À1 .…”

“…Assuming that similar overestimations are also valid for D SS of the quintet dinitrenes 6 and 7 as well as of septet trinitrene 8, these nitrenes are predicted to show D values of~0.202, 0.157, and~0.089 cm À1 , respectively. [4][5][6][7][8]12] According to Equation (4), a decrease from V = 1208 by 18 results in an increase of j E S j by approximately 0.0011 cm À1 . Consequently, it seems that the photolysis of triazide 3 occurs selectively, generating subsequently triplet mononitrene 4, quintet dinitrene 6, and septet trinitrene 8.…”

“…[a] Dr. P. Neuhaus, Prof. Dr. W. Sander Lehrstuhl für Organischen Chemie II, Ruhr-Universität 44780 Bochum (Germany) E S = À0.004 cm À1 ) [7] and septet 2,4,6-trinitreno-3,5-dicyanopyridine (D S = À0.1011 cm À1 , E S = 0.0043 cm À1 ). [8] Aryl polynintrenes with S > 3 can be synthesized by photolysis of the corresponding polycyclic aromatic polyazides in low temperature matrices.…”

Magnetic Field‐Enhanced 4‐Electron Pathway for Well‐Aligned Co3O4/Electrospun Carbon Nanofibers in the Oxygen Reduction Reaction

“…According to transition state theory,m agnetic field-induced degeneracy on unpaired electron spins generates enhanced electron energy states that contribute to the activation energy for electron-transfer reactions. [51] The increase in Zeeman energy, gbHS p , [52] in Co 3 + /2 + in the presence of am agnetic field contributest ot he activation energy by reducingt he net enthalpy of the activation barriera nd thereby facilitating the redox reaction rate. [51] The increase in Zeeman energy, gbHS p , [52] in Co 3 + /2 + in the presence of am agnetic field contributest ot he activation energy by reducingt he net enthalpy of the activation barriera nd thereby facilitating the redox reaction rate.…”

High-spin organic molecules with dominant spin-orbit contribution and unprecedentedly large magnetic anisotropy

“…In principle, the sign of the parameter D can be derived from temperature-dependent ESR spectra, if such spectra display relatively strong lines at H > 600 mT. 3 Because the ESR spectra of Q-1, Q-2, and S-1 do not display strong transitions at H > 600 mT, only absolute values of |D| for these nitrenes were experimentally determined.…”