TY - JOUR

T1 - Molecular characterization of hexaoctyloxy-rufigallol in the solid and columnar phases

T2 - A local field NMR study

AU - Dvinskikh, Sergey V.

AU - Luz, Zeev

AU - Zimmermann, Herbert

AU - Maliniak, Arnold

AU - Sandström, Dick

PY - 2003/3/6

Y1 - 2003/3/6

N2 - Separated local field NMR spectroscopy was used to obtain 1H-13C dipolar interactions in the solid and columnar phases of the discotic compound 1,2,3,5,6,7-hexaoctyloxy-rufigallol (RufH8O). The couplings were measured and assigned by a variety of advanced NMR techniques performed under both static and magic-angle spinning conditions. The analysis of the dipolar couplings shows that the three nonequivalent aliphatic chains in RufH8O exhibit vastly different structural and dynamical characteristics. It was also found that one of the α methylene signals exhibits two 1H-13C dipolar splittings at low temperatures in the columnar phase. Similar pairs of doublets have previously been observed in a 2H NMR study of RufH8O-2Hα and were there interpreted in terms of dynamic packing fluctuations along the columns. We will present an alternative explanation and show that these two doublets most likely originate from nonequivalent protons (or deuterons) in the α methylene group and not from density modulations.

AB - Separated local field NMR spectroscopy was used to obtain 1H-13C dipolar interactions in the solid and columnar phases of the discotic compound 1,2,3,5,6,7-hexaoctyloxy-rufigallol (RufH8O). The couplings were measured and assigned by a variety of advanced NMR techniques performed under both static and magic-angle spinning conditions. The analysis of the dipolar couplings shows that the three nonequivalent aliphatic chains in RufH8O exhibit vastly different structural and dynamical characteristics. It was also found that one of the α methylene signals exhibits two 1H-13C dipolar splittings at low temperatures in the columnar phase. Similar pairs of doublets have previously been observed in a 2H NMR study of RufH8O-2Hα and were there interpreted in terms of dynamic packing fluctuations along the columns. We will present an alternative explanation and show that these two doublets most likely originate from nonequivalent protons (or deuterons) in the α methylene group and not from density modulations.

UR - http://www.scopus.com/inward/record.url?scp=0344950396&partnerID=8YFLogxK

U2 - 10.1021/jp0274381

DO - 10.1021/jp0274381

M3 - Article

AN - SCOPUS:0344950396

VL - 107

SP - 1969

EP - 1976

JO - Journal of Physical Chemistry B

JF - Journal of Physical Chemistry B

SN - 1520-6106

IS - 9

ER -