title: The effect of leaving radical on the formation of tetrahydroselenophene by SHi ring closure: an experimental and computational study.
abstract: Competition kinetic studies augmented with laser-flash photolysis and high-level computational techniques [G3(MP2)-RAD], with [COSMO-RS, SMD] and without solvent correction, provide kinetic parameters for the ring closures of a series of 4-(alkylseleno)butyl radicals 1. At 22 °C rate constants (kc) that lie between 10(4)-10(7) s(-1) were determined experimentally and correlate with expectations based on leaving group ability. Activation energies (Eact) were determined to lie between 10.6 (R = Ph2CH) and 28.0 (R = n-Bu) kJ mol(-1), while log(A/s(-1)) values were generally between 9 and 10 in benzene. Computationally determined rate constants were in good-to-excellent agreement with those determined experimentally, with the COSMO-RS solvation model providing values that more closely resemble those from experiment than SMD.
authors.affiliation: ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, Australia. carlhs@unimelb.edu.au.
authors.forename: Amber N
authors.initials: AN
authors.lastname: Hancock
authors.forename: Sofia
authors.initials: S
authors.lastname: Lobachevsky
authors.forename: Naomi L
authors.initials: NL
authors.lastname: Haworth
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Coote
authors.forename: Carl H
authors.initials: CH
authors.lastname: Schiesser
mesh_terms: D005609:Free Radicals / Q000737:chemistry; D007700:Kinetics; D015394:Molecular Structure; D016566:Organoselenium Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D011789:Quantum Theory
chemical_list: D005609:Free Radicals; D016566:Organoselenium Compounds