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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

, , , , und . European Journal of Inorganic Chemistry, (2000)
DOI: 10.1002/1099-0682(200007)2000:7{\textless}1475::AID-EJIC1475{\textgreater}3.0.CO;2-N

Zusammenfassung

The thermolysis of tetra(supersilyl)dialane R2Al-AlR2 (R = SitBu3 = Supersilyl) in heptane or cyclohexane at 50° leads under Al-Al dissocn. reversibly to monoalanyl radicals R2Al.bul., which could be trapped by hydrogen or iodine (formation of R2AlH, R2AlI). Simultaneously, SiAl dissocn. and elimination of supersilyl radicals tBu3Si.bul. leads irreversibly and slowly to radicals R2Al-AlR.bul., the existence of which could be established by ESR spectroscopy. The structure was clarified by ab initio calcns. (nearly planar Si2Al-AlSi and linear Al-Al-Si skeleton; short Al-Al distance). By thermolyzing R2Al-AlR2 at 100°, the radical R4Al3.bul. (ESR spectroscopically detected) and the tetrahedro-tetraalane R4Al4 (NMR spectroscopically seen) are formed via radicals R3Al2.bul.; the supersilyl radicals tBu3Si.bul., 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 anal., the Al atoms in R4Al3.bul. 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. on SciFinder(R)

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