Spectroscopic identification of the phenyltelluryl radical and its reactivity toward molecular oxygen

Abstract

Phenyltelluryl radical and its primary oxidation products phenyltelluro peroxy and phenyl telluroyl radicals were generated and characterized spectroscopically in solid noble gas matrices for the first time.

Generation and reactivity of vinyltelluryl radical

“…We recently reported the preparation of phenylthiyl, phenylselenyl, and phenyltelluryl radicals by thermal or photochemical decomposition of the corresponding diphenyl dichalcogenides. 35,39,40 In line with previous studies, we first attempted the generation of 5 by photolysis of divinylditelluride (6) and subsequent trapping and isolation in an inert argon matrix at 10 K (Scheme 2). Photolysis of the matrix-isolated 6 produces a large amount of acetylene, evident by the strong absorption bands at 3265 and 738 cm À1 (Fig.…”

“…The spin density in 5 is in the same range as phenylthiyl, phenylselenyl and phenyltelluryl radicals, respectively. 35,39,40 The bond dissociation energy (BDE) of the Te-Te bond in 6 is 40.9 kcal mol À1 at the UB3LYP/def2-QZVPP level (including zero-point vibrational energy correction (ZPVE)). The BDEs in Scheme 2 Vinyltelluryl radical 5 generated through pyrolysis of divinylditelluride 6 trapping in an argon matrix and subsequent (photo)reactivity.…”

“…The C–Te bond distance in 5 is 2.089 Å, which is in the same range as the phenyltelluryl radical (2.102 Å). 35 The CC bond distance is 1.336 Å, in a typical alkene range. The spin density in 5 is mainly localized on the Te atom (0.898) due to the larger atomic orbital (AO) size of tellurium; this is in marked contrast to ally radical 1 , where an unpaired electron is delocalized over a system of the conjugated π bond (Fig.…”

“…The spin density in 5 is in the same range as phenylthiyl, phenylselenyl and phenyltelluryl radicals, respectively. 35,39,40…”

“…32,33 Donovan et al reported the UV/Vis spectrum for Te-H radical and identified the Rydberg series and the first ionization potential. 34 Recently, we reported the generation and matrix isolation of the phenyltelluryl radical and its reaction with oxygen, 35 which is an important reactive intermediate in radical polymerization reactions. [36][37][38] As part of our ongoing studies on heteroatom radicals, we are now able to prepare and isolate in argon matrix the elusive vinyltelluryl radical.…”