A computational investigation of the effect of the double bond on the conformations of seven membered rings

作者：Groenewald Ferdinand; Mateura Milcent; Dillen Jan^*

来源：Structural Chemistry, 2013, 24(1): 243-250.

DOI：10.1007/s11224-012-0073-4

• DFT
• CCSD(T)
• Atoms in molecules

The effect of the presence of an exo- and/or an endo double bond on the geometry of seven membered rings has been investigated by a conformational analysis of methylenecycloheptane, cycloheptamine, borepane, and 4-, 3- and 2-cyclohepten-1-one by the B3LYP/6-311+G(d,p) and CCSD(T)/6-311+G(d,p) levels of theory. The results indicate that both methylenecycloheptane and cycloheptamine have low energy barriers with respect to pseudorotation and a broad potential well centred on the most symmetrical twist-chair conformation. Borepane shows similar characteristics, but with drastically different relative energy values. The introduction of an extra endo double bond in the conformationally flexible cycloheptanone, fixes the family of chair conformations to a single rigid form, but lowers the relative energy of the boat conformations to compete in stability with the former.

• 出版日期2013-2