Elucidating the Origin of Conformational Energy Differences in Substituted 1,3-Dioxanes: A Combined Theoretical and Experimental Study
作者:Piotr Cieplak、Allison E. Howard、Jay P. Powers、Scott D. Rychnovsky、Peter A. Kollman
DOI:10.1021/jo951918p
日期:1996.1.1
13C NMR spectroscopy, ab initio quantum mechanics, and molecular mechanics have been used to investigate the trans-4-(trifluoromethyl)-2,2,6-trimethyl-1,3-dioxane chair/twist-boat equilibrium. The molecular mechanics calculations were based upon the MM3 and AMBER force fields. A 6-31G basis set was used for the ab initio calculations, and MP2 correlation corrections were applied. Both the ab initio
13 C NMR光谱,从头算量子力学和分子力学已被用来研究反式4-(三氟甲基)-2,2,6-三甲基-1,3-二恶烷椅子/扭转船的平衡。分子力学计算基于MM3和AMBER力场。从头算起使用6-31G基础集,并应用MP2相关校正。从头计算和AMBER分子力学计算均与反式4-(三氟甲基)-2,2,6-三甲基-1,3-二恶烷构象异构体的(13)C NMR化学位移差异一致。MM3计算结果表明,预计的扭曲船平衡椅与实验数据不一致。这些结果支持了霍华德等人的建议。(AE霍华德; P.Cieplak; PAJ Kollman,Comput.Chem。1995,16