Effects of hyperconjugative interactions on ¹J CH coupling constant for hexamethyl-enetetramine and adamantane: theoretical and experimental study

Author(s)

Francisco P. dos Santos ^[1] ; Lucas C. Ducati ^[2] ; Cláudio F. Tormena ^[3] ; Roberto Rittner ^[4]

Affiliation

^[1] Universidade Estadual de Campinas. Instituto de Química - Brasil

^[2] Universidade Estadual de Campinas. Instituto de Química - Brasil

^[3] Universidade Estadual de Campinas. Instituto de Química - Brasil

^[4] Universidade Estadual de Campinas. Instituto de Química - Brasil

• Document type: Journal article
• Source: Química Nova; v. 30, n. 7, p. 1681-1685, 2007-00-00.

Abstract

The objective of this work was to determine the influence of hyperconjugative interactions on the ¹J CH coupling constant for hexamethylenetetramine (1) and adamantane (2). For this end, theoretical and experimental ¹J CH were obtained and hyperconjugative interactions were investigated using NBO. It was observed, theoretically and experimentally, that ¹J CH in 1 is 20 Hz larger than in 2, mainly due to the nN<FONT FACE=Symbol>®s</FONT>*C-H hyperconjugative interaction. This interaction occurs only in 1, with an energy of 9.30 kcal mol-1. It increases the s-character of the carbon atom in the C-H bond and the occupancy of the sigma*C-H orbital in (1). (AU)

• FAPESP's process: 06/03980-2 - Interacoes de orbitais e seus efeitos nas constantes de acoplamento escalar em rmn: estudo experimental e teorico.
• Grantee: Claudio Francisco Tormena
• Support Opportunities: Regular Research Grants
• FAPESP's process: 05/59649-0 - Conformational equilibria studies by nuclear magnetic resonance spectroscopy, infrared spectroscopy and theoretical calculations
• Grantee: Roberto Rittner Neto
• Support Opportunities: Research Projects - Thematic Grants