Triplet aryl cation (3Ar+): its photostimulated and thermal conversion into Ar· and role as the primary intermediate in matrix photochemistry of ArN2+ ions

Abstract

Photolysis at 77 K of 2,4,5-trimethoxybenzenediazonium hexafluorophosphate (ArN₂⁺PF₆^–) yields ³Ar⁺ and Ar· in a ratio dependent on (i) irradiation wavelength, (ii) light intensity, (iii) matrix, (iv) photolysis time, and under selected Conditions, i.e.λ_irr >350 nm, low intensity, microcrystalline matrix, short photolysis time, [³Ar⁺]/[Ar·] exceeds 10, implying that ³Ar⁺ is the primary photoproduct; ³Ar⁺ transforms into Ar· in the dark (in any matrix), and this change is accelerated under irradiation.