Molecular characterization of hexaoctyloxy-rufigallol in the solid and columnar phases: A local field NMR study
2003 (English)In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 107, no 9, 1969-1976 p.Article in journal (Refereed) Published
Separated local field NMR spectroscopy was used to obtain H-1-C-13 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 alpha methylene signals exhibits two H-1-C-13 dipolar splittings at low temperatures in the columnar phase. Similar pairs of doublets have previously been observed in a H-2 NMR study of RufH8O-H-2(alpha) 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 alpha methylene group and not from density modulations.
Place, publisher, year, edition, pages
2003. Vol. 107, no 9, 1969-1976 p.
nuclear-magnetic-resonance, x-ray-diffraction, liquid-crystals, state nmr, rotating solids, pulse sequences, symmetry principles, spin-diffusion, spectroscopy, couplings
IdentifiersURN: urn:nbn:se:kth:diva-22296DOI: 10.1021/jp0274381ISI: 000181366800008OAI: oai:DiVA.org:kth-22296DiVA: diva2:340994
QC 201005252010-08-102010-08-10Bibliographically approved