Trapping and Imaging Molecular Dynamics by Combining Scanning Force Microscopy with Topology

✍ Scribed by Prof. Bruno Samori; Dr. Carmelo Nigro; Amalia Gordano; Dr. Innocenzo Muzzalupo; Dr. Carla Quagliariello

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 341 KB
• Volume: 35
• Category: Article
• ISSN: 0044-8249
• DOI: 10.1002/anie.199605291

✦ Synopsis

change can be extended to encompass 1,3-dilithiated compounds of general formula Li-CH,-E-CH,-Li (E = element of group 14-16, possibly with substituents).

Experimental Procedure 2 (froin starting material 1): Bu,SnCH,I (20 mmol) was added to a suspension of Na,S.AI,O, (11 mmol) in THF (30 mL). The mixture was stirred at room temperature for 16 h, after which the solvent was removed under vacuum. The residue was extracted three times with 28 mL portions of hexane. The solvent was removed and, following purification by Kugelrohr distillation (oven temperdture 165 "C/ 0.001 Torr), compound 2 was obtained in 92% yield as a colorless oil. 'H NMR (200.1 MHz, CDCI,, 25°C. TMS). 6 = 0.75-1.1 (m, 12H; CH,. SnCH,C), 1.2-1.4, 1.4-1.7(m,42H;CCH2C,CCH,).2.00(s,4H, 'J(H,Sn) = 40.4Hz;SnCH2S); I3C NMR (80.3 MHz, CDCI,, 25°C. CDCI,): 6 = 9.6 (6C, 'J(C,i'y'117Sn) = 329.6/318.0 Hz; SnCH,C), 13.7 (6C, CCH,), 17.3 (2C, 'J(C,"9"'7Sn) = 233.7/ 223.2 Hz. 'J(C,Sn) = 30.3 Hz; SnCH,S), 27.3 (6C. 3J(C,i'9"'7Sn) = 55.91 83.7 Hz; SnCH,CH,CH,C), 29.1 (6C, 'J(C,Sn) = 20.8 Hz: SnCH,CH,C); IL9Sn NMR (74.6MHz, CDCI,, 28"C, SnMe,): 6 = -18 3; MS (El, 70eV): m/z (70) [HSnBu:], 238 (78) [H,SnBu:], 179 (100) [H,SnBu+]; correct elemental analysis for C,,H,,SSn, 2 and 3 (from 6): Under an inert atmosphere 6 (10 mmol) was dissolved in Et,O (50 mL). and at -30°C d solution of n-BuLi (20 mmol) in hexane was added. The mixture was stirred for 5 mln at this temperature. Upon warming to room temperature 4 precipitated as a colorless solid. After centrifugation, the by-product TeBu, was removed with the supernatant. and the precipitate was washed with diethyl ether. This centrifugation-washing step was repeated four times. To the resulting suspension of 4 in Et,O (approx. 30 mL) was added at -20 "C a solution of Bu,SnCI (or Me,PhSiCI for 3) (20 mmol), in 5 mL Et,O. The mixture was warmed to room temperature, the solvent removed. and the mixture worked up as previously described (vide supra). Yield: 89% 2/74% 3 (purification by Kugelrohr distillation at 188 "C oven temperature/0.001 Torr). Analogously, 3 was obtained from 2 employing THF as solvent. Yield: 84% [14].

6: Under an inert atmosphere a solution of BuTeLi was prepared by combining tellurium powder (12.8g, 0.1 mol) in THF (150mL) with a solution of n-BuLi (0.1 mol) in hexane (42 mL). Next. 5 (0.05 mol) dissolved in THF (8 mL) was added at -78 "C. The solution was allowed to warm to room temperature over 1 h, and volatile components were removed under vacuum. The residue was extracted with four 100 mL portions of hexane and volatile components were again removed under vacuum. Compound 6 was obtained as a colorless oil (traces of ditellurides can render the compound red) in 83 % yield after Kugelrohr distillation at 135 "C oven temperature/0.001 Torr. 'H NMR (200.1 MHz. CDCI,, 2 5 °C TMS): 6 = 0.87 (t. 6H, "(H,H) =7.2 Hz; CCH,), 1.34 (sextet, 4H, 'J(H,H) = 7 3 Hz; CCH,CH,), 1.73 (quin. 4H, 'J(H,H) ~7 . 4

Hz; CH,CH,CH,). 2.72 (t, 4H. 'J(H,H) =7.8 Hz; TeCH,C), 3.69 (s, 4H, 'J(H.Te) = 32.3 Hz; TeCH,S); I3C NMR (50.3 MHz, CDCI,, 2 8 °C CDCI,): 6 = 5.0 (2C. 'J(C,Te) = 201.2 Hz: TeCH,S), 8.4 (2C, 'J(C,Te) =181.4Hz; TeCH'C), 13.3 (2C, CCH,), 24.9 (2C. 3J(C,Te) =10.7 Hz, CCH,CH,), 33.9 (2C. 'J(C,Te) = 9.8 Hz; TeCH,CH,C); '"Te NMR (63.2 MHz, CDCI,. 2 8 °C TeMe,): 6 = 303.4; MS (EI. 70eV)m/z (%) = 430 (2) [M+], 373 (22) [ M i -C,H9], 58 (100) [C,H:,]; correct elemental analysis for C,,H,,STe,.