Liquid crystalline behavior of tetraaryl derivatives of benzo[c]cinnoline, tetraazapyrene, phenanthrene, and pyrene: the effect of heteroatom and substitution pattern on phase stability
Synthesis of 1,3,6,8-Tetrabromophenanthrene via a Stoichiometric Ullmann Reaction
摘要:
1,3,6,8-Tetrabromophenantherene (1) is prepared in four steps from 2,4,6-tribromobenzoic acid (4) in an overall yield of 12%. The key transformation used in the synthesis is a stoichiomteric Ullmann reaction.
Liquid crystalline behavior of tetraaryl derivatives of benzo[c]cinnoline, tetraazapyrene, phenanthrene, and pyrene: the effect of heteroatom and substitution pattern on phase stability
作者:Monika J. Sienkowska、John M. Farrar、Fan Zhang、Sharat Kusuma、Paul A. Heiney、Piotr Kaszynski
DOI:10.1039/b615545f
日期:——
A series of closely related tetrasubstituted derivatives of benzo[c]cinnoline (1), tetraazapyrene (2), phenanthrene (3), and pyrene (4) were investigated for their mesogenic properties using thermal, optical, spectroscopic, and powder XRD analyses. Only three 3,4-dioctyloxyphenyl derivatives exhibited mesogenic properties. Substitution of N for CH (3
→
1 and 4
→
2 pairs) and also increase of the core element size (1
→
2 and 3
→
4 pairs) significantly increases the mesophase stability. The findings and observed trends were rationalized by analysis of conformational properties which included calculation of the planarization energy, and modeling of aliphatic chain density and fill fractions. MO calculations showed that the tetraaza derivative 2c is significantly electron deficient and suitable for electron conductive materials.
Synthesis of 1,3,6,8-Tetrabromophenanthrene via a Stoichiometric Ullmann Reaction
作者:John M. Farrar、Monika Sienkowska、Piotr Kaszynski
DOI:10.1080/00397910008087019
日期:2000.11
1,3,6,8-Tetrabromophenantherene (1) is prepared in four steps from 2,4,6-tribromobenzoic acid (4) in an overall yield of 12%. The key transformation used in the synthesis is a stoichiomteric Ullmann reaction.