We use cookies to ensure that we give you the best experience on our website. By continuing to browse this repository, you give consent for essential cookies to be used. You can read more about our Privacy and Cookie Policy.

Durham e-Theses
You are in:

Bis- and Tris-(1,2,3,4-Dithiadiazolium) salts and related radicals

Luke, Anthony W. (1992) Bis- and Tris-(1,2,3,4-Dithiadiazolium) salts and related radicals. Doctoral thesis, Durham University.



Using the cycloaddition of [SNS][AsF(_6)] to nitriles a variety of 5-substituted-1,3,2,4- dithiadiazolium salts (salts containing the -CNSNS cationic ring) were prepared : mono- (1,3,2,4-dithiadiazolium) salts from mononitriles, bis-(l,3,2,4-dithiadiazolium) salts from dinitriles and l,3,5-tris-(l,3,2,4-dithiadiazohum) salts from 1,3,5-tricyanobenzene. salts of these dithiadiazolium cations with other anions were prepared by simple anion metathesis reactions. Bis- and tris-(l,3,2,4-dithiadiazolium) salts were reduced to give stable bis- and tris- (1,3,2,4-dithiadiazolyl) radicals which were studied by electron spin resonance spectroscopy (ESR). These multiradicals were formed as dark, sparingly soluble powders upon reduction of a dithiadiazolium salt. Bis- and tris-(l,3,2,4-dithiadiazolyl)s were shown by ESR to undergo rearrangement in solution to the more stable 1,2,3,5-dithiadiazolyl isomer (containing the -CNSSN ring). Preparation of the l,3,5-rm-(l,3,2,4-dithiadiazolium) iodide [C6H3-1,3,5-(CNSNS)(_3)][I](_3)] in an ESR tube gave a series of ESR spectra similar to those observed for dithiadiazolyl radicals. Reduction of the l,3,5-rm-(l,3,2,4-dithiadiazolium) cation [C(_6)H(_3)-1,3,5-(CNSNS)3](^3+) gave a material identified by elemental analysis as l,3,5-tris-(dithiadiazolyl). Reoxidation of this material with bromine gave a tris-(tribromide) salt [C(_6)H(_3)-1,3,5-(CN(_2)S(_2))(_3)] [Br(_3)](_3). In the same way, reoxidation of the bis-(dithiadiazolyl) [C(_6)H(_4)-1,3-(CN(_2)S(_2))(_2)] gave a bis- (tribromide) [C(_6)H(_4)-l,3-(CN(_2)S)(_2)][Br(_3)]2.1,3,2,4-dithiadiazolium cations were found to initiate the cationic ring-opening polymerization of tetrahydrofuran, and samples of high molecular weight po/y(THF) with low polydispersity initiated by [PhCNSNS][AsF(_6)] and [C(_6)H(_3)-l,3,5-(CNSNS)(_3)][AsF(_6)](_3) were prepared and studied. The reaction of 1,3,2,4-dithiadiazoUum salts with water was studied, and it was shown by infrared and NMR spectroscopy that one dithiadiazolium ring reacts with two equivalents of water, with a 1:1 reaction compound not being formed. The 1,2,3,5-dithiadiazolyl dimer (PhCNSSN)(_2) was found to dechlorinate the activated quinone o-chloranil to give [PhCNSSN]Cl and a quinone coupling product

Item Type:Thesis (Doctoral)
Award:Doctor of Philosophy
Thesis Date:1992
Copyright:Copyright of this thesis is held by the author
Deposited On:16 Nov 2012 10:56

Social bookmarking: del.icio.usConnoteaBibSonomyCiteULikeFacebookTwitter