EPR spectroscopy of multicomponent, multispin molecular system obtained by the photolysis of 2,4,6-triazido-3-cyano-5-fluoropyridine in solid argon

Abstract

Complex multicomponent, multispin molecular system, consisting of a septet trinitrene, two quintet dinitrenes, and three triplet mononitrenes, was obtained by the photolysis of 2,4,6-triazido-3-cyano-5-fluoropyridine in solid argon. To identify these paramagnetic products, electron paramagnetic resonance spectroscopy in combination with line-shape spectral simulations and density functional theory calculations was used. The products of the photolysis was found to be triplet 2,4-diazido-3-cyano-5-fluoropyridyl-6-nitrene (D_T = 1.000 cm^-1 , E_T = 0), triplet 2,4-diazido-3-cyano-5-fluoropyridyl-2-nitrene (D_T = 1.043 cm^-1 , E_T = 0), triplet 2,6-diazido-3-cyano-5-fluoropyridyl-4-nitrene (D_T = 1.128 cm^-1 , E_T = 0 cm^-1 ), quintet 4-azido-3-cyano-5-fluoropyridyl-2,6-dinitrene (D_Q = 0.211 cm^-1 , E_Q = 0.0532 cm^-1 ), quintet 2-azido-3-cyano-5-fluoropyridyl-4,6-dinitrene (D_Q = 0.208 cm^-1 , E_Q = 0.0386 cm^-1 ), and septet 3-cyano-5-fluoropyridyl-2,4,6-trinitrene (D_S = -0.1017 cm^-1 , E_S = -0.0042 cm^-1 ) in a 38:4:7:22:14:4 ratio, respectively.

Keywords: EPR spectroscopy; azides; high-spin states; matrix isolation; nitrenes; photolysis.