In this paper, the difficulty in orienting the B-2 phase of the banana mesogen 1,3-Phenylene-bis 4-[4-(10-undecenyloxy)- benzoyloxy] benzoate ( Pbis11BB) in a relatively high magnetic field is reported based on some observations using both C-13 and H-2 NMR. H-2 NMR spectra recorded for the two labeled isotopomers of Pbis11BB in the isotropic and B-2 phases are shown here. Preliminary results on the deuteron spin-spin relaxation (T-2) data are reported at 61 MHz in order to underline the peculiar slow dynamics of banana-shaped liquid crystals (BLC), and these results are discussed in the framework of recent studies on similar BLC. The molecular structure and dynamics in the B-2 and crystalline phases are also studied by C-13 solid-state NMR techniques. The results also point to the slow dynamics in the B-2 phase of Pbis11BB. In particular, two-dimensional MAS exchange experiment has been performed to shed light on the molecular conformation structure of the five-ring banana core in the crystalline phase of Pbis11BB, and to compare with that of quantum mechanical calculations reported in the literature.

C-13 and H-2 NMR study of structure and dynamics in banana B-2 phase of a bent-core mesogen

DOMENICI, VALENTINA;VERACINI, CARLO ALBERTO
2006

Abstract

In this paper, the difficulty in orienting the B-2 phase of the banana mesogen 1,3-Phenylene-bis 4-[4-(10-undecenyloxy)- benzoyloxy] benzoate ( Pbis11BB) in a relatively high magnetic field is reported based on some observations using both C-13 and H-2 NMR. H-2 NMR spectra recorded for the two labeled isotopomers of Pbis11BB in the isotropic and B-2 phases are shown here. Preliminary results on the deuteron spin-spin relaxation (T-2) data are reported at 61 MHz in order to underline the peculiar slow dynamics of banana-shaped liquid crystals (BLC), and these results are discussed in the framework of recent studies on similar BLC. The molecular structure and dynamics in the B-2 and crystalline phases are also studied by C-13 solid-state NMR techniques. The results also point to the slow dynamics in the B-2 phase of Pbis11BB. In particular, two-dimensional MAS exchange experiment has been performed to shed light on the molecular conformation structure of the five-ring banana core in the crystalline phase of Pbis11BB, and to compare with that of quantum mechanical calculations reported in the literature.
Xu, J; DONG Y., R; Domenici, Valentina; FODOR CSORBA, K; Veracini, CARLO ALBERTO
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11568/183712
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 34
  • ???jsp.display-item.citation.isi??? 36
social impact