Development and validation of an integrated computational approach for the modeling of cw-ESR spectra of free radicals in solution: p-(methylthio)phenyl nitronylnitroxide in toluene as a case study.
In this work we address the interpretation, via an ab initio integrated computational approach, of continuous wave electron spin resonance (cw-ESR) spectra of p-(methylthio)phenyl nitronylnitroxide (MTPNN) dissolved in toluene. Our approach is based on the determination of the spin Hamiltonian, averaged with respect to fast vibrational motions, with magnetic tensor parameters (Zeeman and hyperfine tensors) characterized by quantum mechanical density functional calculations. The system is then described by a stochastic Liouville equation, with inclusion of diffusive rotational dynamics. Parametrization of diffusion rotational tensor is provided by a hydrodynamic model. Cw-ESR spectra of MTPNN are simulated for a wide range of temperatures (155-292 K) with minimal resorting to fitting procedures, proving that the combination of sensitive ESR spectroscopy and sophisticated modeling can be highly helpful in providing structural and dynamic information on molecular systems.
Barone
Vincenzo
V
Dipartimento di Chimica and INSTM, Università di Napoli Federico II, Complesso Universitario di Monte Sant'Angelo Via Cintia, I-80126 Napoli, Italy. baronev@unin.it
Brustolon
Marina
M
Cimino
Paola
P
Polimeno
Antonino
A
Zerbetto
Mirco
M
Zoleo
Alfonso
A