The Nature of Through-Bond Coupling

As another example, let us consider the two lone-pair levels in diazabicyclooc-tane I 1.33. The direct, through-space interaction between the hybrid lone pairs of nitrogen leads to the symmetry-adapted levels and n shown in 11.34. Because 

11 ORBITAL INTERACTIONS THROUGH SPACE AND THROUGH BONDS 

Competition between through-space and through-bond interactions often gives rise to interesting results. For example, let us consider tricyclo-3,7-octadiene which can adopt either the anti or the syn structure shown in I 1.39a and I 1.39b, respectively. In the anti structure the through-space interaction between the 

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