1,2,3-Benzodithiazolyl radicals formed by thermolysis and photolysis of 1,3,2,4-benzodithiadiazines

1,2,3-Benzodithiazolyl radicals formed by thermolysis and photolysis of 1,3,2,4-benzodithiadiazines Full article

Journal

Physical Chemistry Chemical Physics
ISSN: 1463-9076 , E-ISSN: 1463-9084

Output data

Year: 2001, Volume: 3, Number: 3, Pages: 409-415 Pages count : 7 DOI: 10.1039/b008408p

Authors

Vlasyuk IV ^1,2 , Bagryansky VA ^1,2 , Gritsan NP ^1,2 , Molin YN ^1,2 , Makarov AY ³ , Gatilov YV ³ , Shcherbukhin VV ⁴ , Zibarev AV ³

Affiliations

1	Institute of Chemical Kinetics and Combustion, Siberian Branch of Russian Academy of Sciences, Noosibirsk, Russia
2	Noosibirsk State University, Noosibirsk, Russia
3	Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences, Noosibirsk, Russia
4	Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia

Mild thermolysis (at 110-150 degreesC) of 1,3,2,4-benzodithiadiazine 1 and its carbocyclic substituted derivatives 2-15 in hydrocarbon solvents quantitatively yields stable 1,2,3-benzodithiazolyl pi -radicals 1(.)-15(.). Kinetics of this reaction can be described as a first-order process. Arrhenius parameters of the effective rate constant are E-a = 80 +/- 8 kJ mol(-1), k(0) = 10(6.4 +/- 1.1) s(-1) for 1(.) in squalane. Room-temperature photolysis of 1(.) in hydrocarbon solvents also affords radical 1(.) in nearly quantitative yield. Quantum yield of photolysis is wavelength dependent and is equal to 0.08 +/- 0.01 at 313 nm in benzene. Experimental hyperfine coupling (hfc) constants in the ESR spectra of 1(.)-15(.) agree fairly well with those calculated at the B3LYP/CC-pVDZ level of theory. Spin density distribution in 1(.)-15(.) is in striking contrast to that of isomeric 1,3,2-benzodithiazolyls but resembles the distribution in correspondingly substituted benzyl radicals. ESR linewidths of radicals 1(.)-15(.) display some features likely related to spin-rotational relaxation.

Vlasyuk I. , Bagryansky V. , Gritsan N. , Molin Y. , Makarov A. , Gatilov Y. , Shcherbukhin V. , Zibarev A.
1,2,3-Benzodithiazolyl radicals formed by thermolysis and photolysis of 1,3,2,4-benzodithiadiazines
Physical Chemistry Chemical Physics. 2001. V.3. N3. P.409-415. DOI: 10.1039/b008408p WOS Scopus

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