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8715238 
Journal Article 
Compounds of silicon and homologues, 134 supersilyl compounds of boron and homologues, 10. - Tri(supersilyl)dialanyl (tBu3Si)3Al2· and tetra(supersilyl)cyclotrialanyl (tBu3Si)4Al3· - New stable radicals of a group 13 element from thermolysis of (tBu3Si)4Al2 
Wiberg, N; Blank, T; Kaim, W; Schwederski, B; Linti, G 
2000 
Yes 
European Journal of Inorganic Chemistry
ISSN: 1434-1948
EISSN: 1099-0682 
7 
1475-1481 
English 
The thermolysis of tetra(supersilyl)dialane R*2Al-AlR*2 (R*= SitBu3 = Supersilyl) in heptane or cyclohexane at 50 °C leads under Al-Al dissociation reversibly to monoalanyl radicals [R*2Al]*, which could be trapped by hydrogen or iodine (formation of R*2AlH, R*2AlI). Simultaneously, SiAl dissociation and elimination of supersilyl radicals tBu3Si* leads irreversibly and slowly to radicals [R*2Al-AlR*]*, the existence of which could be established by ESR spectroscopy. The structure was clarified by ab initio calculations (nearly planar Si2Al-AlSi and linear Al-Al-Si skeleton; short Al-Al distance). By thermolyzing R*2Al-AlR*2 at 100 °C, the radical [R*4Al3]* (ESR spectroscopically detected) and the tetrahedro-tetraalane R*4Al4 (NMR spectroscopically seen) are formed via radicals [R*3Al2]*; the supersilyl radicals tBu3Si*, formed at the same time, are stabilized by dimerization to superdisilane R*-R* and by taking up hydrogen, giving supersilane R*-H. According to X-ray structure analysis, the Al atoms in [R*4Al3]* are located at the corners of a triangle; one Al atom is connected with two groups R*, the remaining two Al atoms each bind one substituent R* in different ways. 
Ab initio calculations; Aluminum; ESR Spectroscopy; Radicals; Silicon