- Studies of organotin(IV)-orthoquinone systems
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The primary process in the reaction of hexaphenylditin with various substituted orthoquinones (Q) is shown to involve attack by the quinone at a phenyl ligand. The intermediate thus formed decomposes to yield Ph3Sn(SQ·), where S(Q·-) is the corresponding semiquinonate. Rearrangement of these species in solution gives rise to biradicals, while intramolecular electron transfer may lead to the formation and precipitation of Ph2Sn(CAT), where CAT2- is the corresponding substituted catecholate. The identification of these processes depends in part on electron paramagnetic resonance spectroscopy. The reaction of Ph3SnCl or Ph2SnCl2 with Na(TBSQ·) (TBSQ·- = 3,5-di-tert-butyl-orthobenzosemiquinonate) results in the formation of Ph2Sn(TBSQ·), which can undergo redistribution and intramolecular electron transfer, so that the solution chemistry of these latter systems is similar to that of the products of the Sn2Ph6 + Q reaction.
- Brown, Martyn A.,McGarvey, Bruce R.,Ozarowski, Andrzej,Tuck, Dennis G.
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p. 165 - 172
(2007/10/03)
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- PARAMAGNETISCHE IONENPAARE ALS VORSTUFEN BEI DER SYNTHESE VON ZINN(IV)-SAUERSTOFFHETEROCYCLEN
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Triorganyltin hydroxides react with catechols in organic solvents in the presence of air oxygen at first to paramagnetic complexes which are investigated by ESR spectroscopy.The reaction has been run using 6 catechols and 5 different organometallic compounds in numerous solvents, so that its general application is proved.The ESR spectra of the solutions show typical hydrogen hyperfine structure and large splittings, which have to be assigned to magnetic coupling of the free electron with 117Sn and 119Sn nuclei.The tin splittings and the g-values significantly depend on the temperature and the solvent.These observations are interpreted in terms of ion pairing effects.A quantitative interpretation is given.The final products of these reactions are diamagnetic compounds which can be isolated in good yields.Based on the elemental analysis, 1H NMR and mass spectroscopy (electron impact, field desorption), the structures are assigned of partly dimerised o-phenylene dioxystannanes.
- Stegmann, H. B.,Schrade, R.,Saur, H.,Schuler, P.,Scheffler, K.
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p. 197 - 214
(2007/10/02)
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