21470-43-9Relevant academic research and scientific papers
Liquid crystalline behavior of tetraaryl derivatives of benzo[c]cinnoline, tetraazapyrene, phenanthrene, and pyrene: The effect of heteroatom and substitution pattern on phase stability
Sienkowska, Monika J.,Farrar, John M.,Zhang, Fan,Kusuma, Sharat,Heiney, Paul A.,Kaszynski, Piotr
, p. 1399 - 1411 (2008/02/07)
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. The Royal Society of Chemistry.
Photoconductivity of liquid crystalline derivatives of pyrene and carbazole
Sienkowska, Monika J.,Monobe, Hirosato,Kaszynski, Piotr,Shimizu, Yo
, p. 1392 - 1398 (2008/02/07)
Two structurally related discogens containing either pyrene (1a) or carbazole (2a) were investigated by thermal, XRD, spectroscopic, and time-of-flight (TOF) methods. Experiments demonstrated for 1a a narrow range Colh phase, which easily forms a glass state at ambient temperature. TOF measurements showed an ambipolar charge transport for 1a with the mobilities on the order of 10-3 cm2 V-1 s-1. The carbazole 2a has two enantiotropic phases (Crcol and Col h) and behaves as a p-type semiconductor. The activation energy for positive charge mobility in 1a was found to be 0.10 ± 0.01 eV. The Royal Society of Chemistry.
