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A conformational analysis of mono and dialkyl ethers of 2,2′‐dihydroxy‐1,1′‐binaphthalene by circular dichroism spectroscopy and cholesteric induction in nematic liquid crystals
Author(s) -
Rosini Carlo,
Rosati Ivana,
Spada Gian Piero
Publication year - 1995
Publication title -
chirality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.43
H-Index - 77
eISSN - 1520-636X
pISSN - 0899-0042
DOI - 10.1002/chir.530070508
Subject(s) - dihedral angle , chemistry , intramolecular force , circular dichroism , hydrogen bond , crystallography , liquid crystal , stereochemistry , molecule , organic chemistry , physics , optics
Abstract The coupling of the analysis of the absorption and circular dichroism (CD) spectra with that of the cholesteric mesophases induced in nematic liquid crystals indicated some interesting conformational features of bridged and nonbridged mono‐ and dialkylethers of optically active 2,2′‐dihydroxy‐1,1′‐binaphthalene. Bridged derivatives are characterized by relatively small dihedral angles. Simple monoalkyl ethers are characterized by larger dihedral angles but they all assume an s‐ cis conformation, owing to the existence of intramolecular hydrogen bonds. Nonbridged dialkylethers prefer even larger dihedral angles and, depending on the bulkiness of the alkyl groups, the s‐ trans conformation can be found. Interestingly, the conformation of dialkylethers is strongly dependent on the structure of the liquid crystal solvent, because the intramolecular hydrogen bond is not possible there. © 1995 Wiley‐Liss, Inc.