- Synthesis, spectroscopic investigations, and molecular structures of 1-elementa-5-stannabicyclo[3.3.01,5]octanes, RR′Sn(CH2CH2CH2)2E (E = NMe, O, S)
-
The 1-elementa-5-stannabicyclo[3.3.01,5]octanes Cl2Sn(CH2CH2CH2)2E (E = NMe, O, S), Me(Cl)Sn-(CH2CH2CH2)2E (E = NMe, O), Me2Sn(CH2CH2CH2)2E (E = NMe, O), and t-Bu2Sn(CH2CH2CH2)2NMe and the stannacyclooctane Me2Sn(CH2CH2CH2)2CH 2 have been prepared by the reaction of the Grignard reagents E(CH2CH2CH2MgX)2 (X = Cl, Br) with tin tetrachloride or organotin halides. The molecular structures of Cl2Sn(CH2CH2CH2)2NMe (1), Cl2Sn(CH2CH2CH2)2O (5), and Cl2Sn(CH2CH2CH2)2S (8) were determined by X-ray analysis. 1 crystallizes in the monoclinic space group Cc (Z = 4) with a = 13.987 (5) ?, b = 7.668 (2) ?, c = 11.213 (3) ?, and β = 112.68 (2)°. The structure was refined to R = 0.027. 5 crystallizes in the monoclinic space group C2/c (Z = 8) with a = 23.034 (7) ?, b = 7.153 (2) ?, c = 13.944 (4) ?, and β = 114.09 (2)°. The structure was refined to R = 0.163. 8 crystallizes in the monoclinic space group P21/a (Z = 4) with a = 11.521 (1) ?, b = 13.869 (3) ?, c = 6.894 (1) ?, and β = 109.57 (1)°. The structure was refined to R = 0.072. As a result of the Sn-N (2.441 ?), Sn-O (2.384 ?), and Sn-S (2.851 ?) interaction, respectively, the tin atoms in 1, 5, and 8 exhibit distorted trigonal-bipyramidal configurations with the heteroatom in apical position. 1H, 13C, and 119Sn NMR studies in solution show conformational equilibria with dominating boat-chair (BC) and chair-chain (CC) conformations. The dynamic behavior of the compounds is interpreted in terms of a combined dissociation-inversion (DI) and ring inversion (RI) mechanism.
- Jurkschat, Klaus,Schilling, J?rgen,Mügge, Clemens,Tzschach, Alfred,Meunier-Piret, Jacqueline,Van Meerssche, Maurice,Gielen, Marcel,Willem, Rudolph
-
-