TY - JOUR
T1 - Steric and electronic situation in the 4-X-4′-[(4′-Y-Phenyl) ethynyl]biphenyl homologous series
T2 - A joint theoretical and spectroscopic study
AU - Ortiz, Pedro D.
AU - Suardíaz, Reynier
AU - De Vega, Laura
AU - Hennrich, Gunnther
AU - Ortiz, Pedro J.
PY - 2010/3/4
Y1 - 2010/3/4
N2 - In this work we have studied the rotational barriers, the polarization of the acetylenic triple bond, and the molecular dipóle moments in the 4-X-4 ′-[(4′-Y-phenyl)ethynyl]biphenyl homologous series using the density functional theory (DFT) and 1D/2D NMR spectroscopy. This series of compounds constitutes an effective base for the acquisition of liquid crystals. The equilibrium, angle (Θeq) and the torsional barriers ΔE(0°) and AE(90°) are not very sensitive to the substituent effects. We have found evidence for the similarity in the π-conjugation of the Y-substituted and X,Y-disubstituted compounds, the latter with mesomorphic properties, by means of the graphic analysis of the relationship between the molecular dipolar moment μ(D) and the difference between the 13C NMR chemical shifts of the acetylenic carbon atoms (Aáci-cn [ppml). The obtained results contribute to a better understanding of the structure-activity relationship for potential, liquid crystalline systems.
AB - In this work we have studied the rotational barriers, the polarization of the acetylenic triple bond, and the molecular dipóle moments in the 4-X-4 ′-[(4′-Y-phenyl)ethynyl]biphenyl homologous series using the density functional theory (DFT) and 1D/2D NMR spectroscopy. This series of compounds constitutes an effective base for the acquisition of liquid crystals. The equilibrium, angle (Θeq) and the torsional barriers ΔE(0°) and AE(90°) are not very sensitive to the substituent effects. We have found evidence for the similarity in the π-conjugation of the Y-substituted and X,Y-disubstituted compounds, the latter with mesomorphic properties, by means of the graphic analysis of the relationship between the molecular dipolar moment μ(D) and the difference between the 13C NMR chemical shifts of the acetylenic carbon atoms (Aáci-cn [ppml). The obtained results contribute to a better understanding of the structure-activity relationship for potential, liquid crystalline systems.
UR - http://www.scopus.com/inward/record.url?scp=77649298092&partnerID=8YFLogxK
U2 - 10.1021/jp911163t
DO - 10.1021/jp911163t
M3 - Article (Academic Journal)
C2 - 20121072
AN - SCOPUS:77649298092
SN - 1089-5639
VL - 114
SP - 2939
EP - 2944
JO - Journal of Physical Chemistry A
JF - Journal of Physical Chemistry A
IS - 8
ER -