Silylindenes and Silylindans¹

The molecular dynamics and reactivity of tris(inden-1-yl)silane: an NMR spectroscopic and X-ray crystallographic study †

“…The 1 H and 13 C NMR spectra of 9 contain four equally intense resonances in each of the C(1)-H(1), C(2)-H(2) and C(3)-H(3) regions; two silicon hydride resonances (1 : 3) are also observed in both the 1 H and 29 Si NMR spectra of 9. The connectivity between the various 1 H, 13 C and 29 Si NMR signals within each of the four individual indenyl ring environments in 9 was ascertained by use of 1 H, 13 C and 29 Si one-and two-dimensional NMR spectroscopic techniques, in a manner directly analogous to that utilised in assigning the NMR spectra of 7. 8 The NMR spectroscopic features observed for compounds 7, 8 and 9 parallel those observed by McMaster and Stobart, who qualitatively examined the dynamic behaviour of poly(η 1indenyl) complexes of germanium and tin (10 to 13).…”

“…Perhaps the most prominent example of this class of molecules is the commercially available compound, bis(inden-1-yl)dimethylsilane, 5. 13 Following a report by Rausch and co-workers 14 in which it is claimed that 5 undergoes symmetry-forbidden [1,3]-silicon shifts, we demonstrated by use of 2D-EXSY (EXchange SpectroscopY) and single selective inversion NMR techniques that the molecular dynamics of this compound can instead be rationalised in terms of [1,5]-silicon shifts, which permute the C s (5-meso) and the C 2 isomers (5-d,l) of this species. 15 Moreover, support for the sequential generation of isoindenes in this process was obtained via treatment of 5 with two equivalents In continuation of our studies pertaining to the dynamics of poly(inden-1-yl)silanes, we have reported on the operation of [1,5]-silicon shifts in tris(inden-1-yl)methylsilane, 7, 8 and tris(inden-1-yl)allylsilane, 8.…”

“…Some 1 H and13 C NMR signal assignments were made by comparison with data obtained for tris(inden-1-yl)methylsilane, 7. Mass spectra: (DEI, m/z (%)): 458(8, [M] ϩ ), 401 (7, [M Ϫ C 4 H 9 ] ϩ ), 343 (74, [M Ϫ C 9 H 7 ] ϩ ), 258 (86, [Si(C 9 H 7 ) 2 ] ϩ ),143 (100, [Si(C 9 H 7 )] ϩ ), 115 (22, [C 9 H 7 ] ϩ ); (high resolution, DEI): calculated for mass 12 C 33 H 34 Si 1 , 458.2430 amu; observed, 458.2426 amu; Anal.…”

Aluminum ansa-Indenyl Compounds. Synthesis, Structures, Dynamic Properties, and Application in the Synthesis of Group 4 ansa-Metallocenes

“…LiNMe 2 and AlMe 2 Cl were purchased from Aldrich and used without further purification. (1-indenyl) 2 SiMe 2 , 3b, {1,2-(3-indenyl) 2 }-C 2 H 4 , 2c,l and (2-Me-1-indenyl) 2 SiMe 2 2p were prepared by literature methods and converted to the corresponding dilithio salts by reaction with n BuLi (2 equiv, 23 °C, overnight in hexanes, followed by filtration, hexane washing, and vacuum drying). (2-Me-4,5-benz-1-indenyl) 2 SiMe 2 2o and (2-Me-4-Ph-1-indenyl) 2 SiMe 2 2p were prepared by literature methods and converted to the corresponding dilithio salts (mono-Et 2 O adducts) by reaction with n BuLi (2 equiv, 23 °C, overnight in Et 2 O, followed by filtration, hexane washing, and vacuum drying).…”

Alkylidenverbrückte, symmetrische, zweikernige Metallocenkomplexe als Katalysatoren für die Propylenpolymerisation

“…Als Lö sungsmittel ist das polare Solvens Diethylether zu bevorzugen. Es hat gegenü ber den unpolareren Lö sungsmitteln Hexan [43,44] oder Xylol [45] den Vorteil, dass die Umsetzungen in kurzer Zeit bei Raumtemperatur ablaufen und die Ausbeuten nahezu quantitativ sind (s. Abb. 2).…”