Vibrational analysis and molecular structure of bipyrazine

✍ Scribed by N. Neto; M. Muniz-Miranda; G. Sbrana

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 820 KB
• Volume: 50
• Category: Article
• ISSN: 1386-1425
• DOI: 10.1016/0584-8539(94)80065-0

✦ Synopsis

A complete vibrational analysis of bipyrazine is presented, based on IR and Raman data and on the predictions of a valence force field initially transferred from 2,2'-bypirimidine. A set of refined force constants, obtained from the experimental data of both molecules, is also proposed to improve the agreement with observed data for the out-of-plane modes. Both experimental data and calculation suggest a centro-symmetric, trans planar conformation for bipyrazine. The vibrational assignment is discussed in terms of the kinetic energy distribution which, unlike the procedure based on the potential energy, is not influenced by numerical values of frequencies and force constants and allows unambiguous identification of normal modes in which each ring moves as a whole. Different frequency shifts for ring vibrations are predicted, for a model related to bipyraxine adsorbed to a metallic substrate through a nitrogen atom, in orrho or meta position relative to the inter-ring