Portal de Periódicos da CAPES

Structural studies of mesogen benzalazine derivatives

1987; Elsevier BV; Volume: 150; Issue: 1-2 Linguagem: Inglês

10.1016/0166-1280(87)80021-0

1872-7999

José Elguero, Carlos Jaime, Mercedes Marcos, Enrique Meléndez, Francisco Sánchez‐Ferrando, José Luís Serrano,

Organic and Molecular Conductors Research

The molecular geometry of benzalazine derivatives was studied by spectroscopic and semiempirical MO (MNDO, CNDO/2) methods. The existence of a strong intramolecular H-bond (7–10 kcal mol−1) was determined by 1H NMR spectroscopy in molecules having a hydroxy group in the ortho position with reference to the diazine central bridge. A study of the H-bonds using the MNDO method proved to be unsatisfactory, whereas the results obtained by the CNDO/2 method were in excellent agreement with experimental values. Both theoretical calculations (CNDO/2) and experimental evidence (UV and 1H NMR) show that the existence of a first H-bond weakened the force of a second in benzalazines.