K. Tamao et al., Synthesis, structure, and reactivity of 1,omega-bis(pseudo-pentacoordinated) 1,omega-difluoro-oligosilanes bearing 8-(dimethylamino)-1-naphthyl groups, J ORGMET CH, 574(1), 1999, pp. 193-205
1,omega-Bis[8-(dimethylamino)-1-naphthyl]-1,omega-difluorotrisilane 1 (omeg
a = 3) and tetrasilane 2 (omega = 4) have been prepared. The X-ray crystall
ography of dl-1 and meso-1 shows unsymmetrical structures having different
coordination modes at the two terminal silicons. The unsymmetrical nature o
f the structure of 1 can also be observed by solid state CP/MAS NMR spectro
scopy. Trisilane 1 is thermochemically labile and undergoes facile degradat
ion at 145 degrees C, but is photochemically stable under irradiation of it
s benzene solution with a 6 W-low pressure mercury lamp, making a sharp con
trast to the behavior of their tetracoordinate counterparts containing naph
thyl groups which are thermochemically stable but photochemically active. T
etrasilane 2 undergoes a Pd(0)-catalyzed alpha-elimination of a fluorosilan
e moiety at the two pseudo-pentacoordinated silicon atoms to form the 1,2-d
ifluorodisilane, which is trapped with diphenylacetylene as a double-silyla
tion product. (C) 1999 Elsevier Science S.A. All rights reserved.