Star-shaped oligomers with truxenone centre and triphenylene branches: mesomorphism, optical and electronic properties

Three star-shaped oligomers with an electron-deficient truxenone (TrO) as the central core and three electron-rich triphenylenes (TP) as the peripheral arms were prepared, in which the triphenylenes groups are, respectively, connected to the central truxenone core at 2, 7 and 12 positions through a...

Full description

Saved in:
Bibliographic Details
Published in:Liquid crystals 2020-05, Vol.47 (7), p.1100-1110
Main Authors: Zhang, Wen, Yu, Wen-Hao, Feng, Chun, Xiang, Shi-Kai, Wang, Bi-Qin, Zhao, Ke-Qing, Ni, Hai-Liang, Hu, Ping
Format: Article
Language:English
Subjects:
Columnar phase
Columnar structure
Dichloromethane
Discotic liquid crystals
Emission
Emissions
Excimers
Liquid crystals
Mesophase
Oligomer
Oligomers
Optical properties
Room temperature
Triphenylene
Truxenone
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Three star-shaped oligomers with an electron-deficient truxenone (TrO) as the central core and three electron-rich triphenylenes (TP) as the peripheral arms were prepared, in which the triphenylenes groups are, respectively, connected to the central truxenone core at 2, 7 and 12 positions through a highly flexible O(CH 2 ) n O (n = 6,8,10) polymethylene chain. All these triphenylene-armed oligomers TrO[O(CH 2 ) n OTP] 3 (n = 6,8,10) exhibit liquid crystalline over broad mesophase ranges including room temperature. Oligomer TrO[O(CH 2 ) 6 OTP] 3 exhibit a rectangular columnar mesophase, while others with the linkage longer show a hexagonal columnar mesophase. This modulation of phase behaviours was demonstrated to be generated by steric perturbations introduced between the three decyloxy substituents in central truxenone core and the linkages with different lengths, which cause the disturbance of the intracolumnar structure and influence the degree of ordering in columnar phases. No new electronic absorption except for the usual bands of the individual truxenone or triphenylene part was observed in dichloromethane solution of TrO[O(CH 2 ) 6 OTP] 3 . However, two new emission peaks emerged and the intensity and position of the emission peaks were found to exhibit pronounced changes upon concentration variation, which can be attributed to the formation of intermolecular excimers.
ISSN:0267-8292
1366-5855
DOI:10.1080/02678292.2019.1706106