Unsymmetrical (1-λ3)-1,2,4,6-thiatriazinyls with aryl and trifluoromethyl substituents: synthesis, crystal structures, EPR spectroscopy and voltammetry

Boeré, René T.; Roemmele, Tracey L.; Yu, Xin

Unsymmetrical (1-λ3)-1,2,4,6-thiatriazinyls with aryl and trifluoromethyl substituents: synthesis, crystal structures, EPR spectroscopy and voltammetry

dc.contributor.author	Boeré, René T.
dc.contributor.author	Roemmele, Tracey L.
dc.contributor.author	Yu, Xin
dc.date.accessioned	2019-03-29T22:20:12Z
dc.date.available	2019-03-29T22:20:12Z
dc.date.issued	2011
dc.description	Sherpa Romeo white journal. This document is the Accepted Manuscript version of a Published Work that appeared in final form in Inorganic Chemistry, copyright © American Chemical Society after peer review and technical editing by the publisher.	en_US
dc.description.abstract	A general synthetic route to 3-trifluoromethyl-5-aryl-1λ3-1,2,4,6-thiatriazinyl radicals was developed. X-ray structures were obtained for all five neutral radicals and show that they exist in the solid state as co-facial dimers linked by S···S contacts. X-ray structures were also obtained for two of the precursor chlorothiatriazines along with several aryl N-imidoylamidines, p-methoxybenzamidine and N-chlorosulfonyl-N,N'-benzamidine. Cyclic voltammetric studies were performed on the [R2C2N3S]• radicals in CH3CN and CH2Cl2 with [nBu4N][PF6] as the supporting electrolyte under vacuum in an all-glass electrochemical cell. The results provide quasi-reversible formal potentials for the [R2C2N3S]−/0 process in the range of −0.61 to −0.47 V, irreversible peak potentials for the [R2C2N3S]0/+ process from 0.59 to 0.91 V at lower concentrations, and the appearance of a second, reversible oxidation process from 0.69 to 0.94 V at higher concentrations (versus the Fc0/+ couple; Fc = Ferrocene). This behavior was indicative of monomer-dimer equilibrium in solution as ascertained from digital models of the voltammograms. There is a small but measurable trend in both the oxidation and reduction potentials with varying remote aryl substituents. EPR spectra were obtained for all five neutral radicals in CH2Cl2 solutions, which confirm concentration of the unpaired electron density on the heterocyclic core. Trends were also seen in the hyperfine splitting constants aN with varying remote aryl substituents. Calculations were performed for all three oxidation states of the [R2C2N3S]-/•/+ monomeric rings; the resulting theoretical redox energies correlate well with solution phase voltammetric data.	en_US
dc.description.peer-review	Yes	en_US
dc.identifier.citation	Boeré, R. T., Roemmele, T. L., & Yu, X. (2011). Unsymmetrical (1λ3)-1,2,4,6-thiatriazinyls with aryl and trifluoromethyl substituents: Synthesis, crystal structures, EPR spectroscopy and voltammetry. Inorganic Chemistry, 50(11), 5123-5135. doi: 10.1021/ic2003996	en_US
dc.identifier.uri	https://hdl.handle.net/10133/5303
dc.language.iso	en_US	en_US
dc.publisher	ACS Publications	en_US
dc.publisher.department	Department of Chemistry and Biochemistry	en_US
dc.publisher.faculty	Arts and Science	en_US
dc.publisher.institution	University of Lethbridge	en_US
dc.publisher.url	https://doi.org/10.1021/ic2003996
dc.subject	Free radical	en_US
dc.subject	Thiatriazinyl	en_US
dc.subject	Electron paramagnetic resonance	en_US
dc.subject	Cyclic voltammetry	en_US
dc.subject	Ionization potential	en_US
dc.subject	Electrochemistry	en_US
dc.subject	DFT calculations	en_US
dc.subject.lcsh	Free radicals (Chemistry)
dc.subject.lcsh	Voltammetry
dc.subject.lcsh	Ionization
dc.subject.lcsh	Electron paramagnetic resonance spectroscopy
dc.title	Unsymmetrical (1-λ3)-1,2,4,6-thiatriazinyls with aryl and trifluoromethyl substituents: synthesis, crystal structures, EPR spectroscopy and voltammetry	en_US
dc.type	Article	en_US