《Phosphorus》.pdf

Phosphorus, Sulfur, and Silicon , 182:793–813, 2007 Copyright © Taylor Francis Group, LLC ISSN: 1042-6507 print / 1563-5325 online DOI: 10.1080/10426500601059383 Structural and Configurational Properties of Ethene, Silaethene, Germaethene, and Stannaethene: A Density Functional Theory Study and Natural Bond Orbital Analysis Davood Nori-Shargh Chemistry Department, Islamic Azad University, Arak, Iran; and 2 Chemistry Department, Islamic Azad University, Hesarak, Poonak, 1 0 Tehran, Iran 2 e n u Fahimeh Roohi J 0 Jila Farajzadeh 1 7 Chemistry Department, Islamic Azad University, Arak, Iran 4 : 8 1 t Farzad Deyhimi a ] Chemistry Department, Shahid Beheshti University, Evin, Tehran, Iran y t i s r e v i n U i B3LYP/6-31G*-B3LYP/3-21G,* and B3LYP/LANL2DZ**-based density func- a h tional theory (DFT) methods were used to investigate the ground-state struc- g n tural and configurational properties of ethene (1), silaethene (2), germaethene a h (3), and stannaethene (4). All three methods showed that the ground-state S [ structure of compounds 1–4 is planar. The results confirmed that the π bond y b energies (rotational barriers) are decreased from compound 1 to 4. The double- d bond rotation energy profiles show the existence of plane symmetrical interme- e d diates, due to the pyramidalization at the silicon, germanium, and tin center a o l in compounds 2–4, respectively. Ba