Effect of steric factors on mesomorphic stability I. 4‐(4‐Substituted phenylazo)‐1‐naphthyl 4‐alkoxybenzoates
Four homologous series belonging to the family of 4-(4-substituted phenylazo)-1-naphthyl 4-alkoxybenzoates ( I a–d) (C n H2 n +1O–C6H4–COO–C10H6–N?=?N–C6H4– X ) were prepared in which the 4- substituent ( X ) was varied between CH3O, CH3, Cl and NO2; while, within each homologous series, the number of carbon atoms, n , was varied between 8 and 14. The compounds were characterized by infrared spectroscopy, 1 H NMR spectroscopy and elemental analysis. Their mesophase behaviour was investigated by differential scanning calorimetry and polarizing-optical microscopy. The results are discussed in terms of mesomeric, polarizability, and steric effects. In each group of compounds bearing the same alkoxy group, attempts were made to correlate the mesophase–isotropic transition temperatures ( T c) with the polarizability anisotropy, ?a x , of bonds to the small compact substituent X .
Document Type: Research Article
Affiliations: Department of Chemistry, Faculty of Science, Cairo UniversityP. O. 12613, Giza, Egypt
Publication date: 01 April 2005
- Editorial Board
- Information for Authors
- Subscribe to this Title
- Ingenta Connect is not responsible for the content or availability of external websites
- Access Key
- Free content
- Partial Free content
- New content
- Open access content
- Partial Open access content
- Subscribed content
- Partial Subscribed content
- Free trial content