Spin adducts between thioketones and phosphorus centred radicals : Part II. An electron spin resonance study of the addition of phophinyl, phosphonyl and thiophosphonyl radicals to diaryl and dialkyl thioketones
✍ Scribed by Angelo Alberti; Massimo Benaglia; M.Catherine Depew; W.Grant McGimpsey; Gian Franco Pedulli; Jeffrey K.S. Wan
- Book ID
- 104203631
- Publisher
- Elsevier Science
- Year
- 1988
- Tongue
- French
- Weight
- 616 KB
- Volume
- 44
- Category
- Article
- ISSN
- 0040-4020
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✦ Synopsis
The paramagnetic adducts between a variety of phosphinyl, pbogphonyl or thiophonphonyl radical8 and thiobcnxophenont, 9.Wxanthen-9-thione, 9,H-thiaxanthtn-9-thione, S,H-selenaxanthen-9-thione and di-tert-butyl thioketone have been generated and studied by means of ESFc e ctroscopy. Attention has been focused on the variations of g( IR PI with the nature of the Iigands I. In the attacking -PL, radicals and with the nature of the thiocarbonylic suhstrates-In all cases the reactions with the precursor8 OS phosphinyl radicals afforded, bceide the expected adducts, additional paramagnetic epecfes, identified ae the corresponding phoephonyl and thiophoaphonyl adduces: while the formation of the former reflects the high sensitivity of tervalent phoophorus compounds to oxidiziny agente, the latter adduct are believed to originate from desulfuration of the thioketones by the starting phosphines. ft ie well estabiished that thfoketones , wing to the presence of the readily as8aifable 0% double bond, posseos a pronounced ability to act au spin trap8 for a variety of free radicalzr, and indeed adducts with species centred at elements ranging from Group Iv to Group VI and at transition metal atom8 have been studied by means of Electron Spin Resonance (ESR) epectroscopy. 1-13 Although several different thiocarbonyle have been used in these etudiee a8 eubstrates for radical additkon, a major drawback preventing a general uue of this class of compounds as routine spin traps in represented my tne relatively low stability of it8 members, which must, with few exceptions, be handled at low temperatures and in Inert atmospheres.
As the result of the several aforementioned kSR Investigations, a substantial body of information ib now available concerning the structural and electronic properties of the spin adducts between thioketonee and carbon, l-5,7,9 ellicon,2'5~9 germanium, 6-9 tin z*5-Q lead 7 oxygen e ' ' or aulphur 13 * t ctntred radical8 a6 well aa the adducts with metal carbonyla. ""2 Fewer reports have however dealt with the spin adducta with phosphorus centred radicals, i.e. --that of the diethoxyphosphonyl aoduct of di-tert-autyl thloketone 2 and or three different tri-thiocarbonates ' by Ingold and coworkers, and d previous study by 8ome of us concerning the adducte of