Relative stabilities of two difluorodiazene isomers: density functional and molecular orbital studies

Abstract:

The N-N bond length in the cis isomer of difluorodiazene is shorter than that in the trans isomer, giving the cis isomer higher stability. The energy partitioning approach identifies the necessary and dictating parameters responsible for the higher N-N bond energy and higher non-bonded F-F interaction energy in the cis isomer. Using density functional theory, the cis isomer is found to have higher chemical hardness and lower softness, and hence, it has higher stability than the trans isomer on the basis of the principle of maximum hardness. Localized molecular orbital study shows that the cis isomer has a higher strength of delocalization of the lone pairs of electrons on the F atoms than does the trans isomer, leading to higher stability of the cis isomer.

Keywords::

• cis/trans isomers
• difluorodiazene
• PMH
• energy partitioning
• localized molecular orbital
• chemical hardness
• softness