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Effect of the Bulkiness of the End Functional Amide Groups on the Optical, Gelation, and Morphological Properties of Oligo( p ‐phenylenevinylene) π‐Gelators
Author(s) -
Babu Sukumaran Santhosh,
Praveen Vakayil K.,
Kartha Kalathil K.,
Mahesh Sankarapillai,
Ajayaghosh Ayyappanpillai
Publication year - 2014
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201402235
Subject(s) - amide , stacking , chemistry , polymer chemistry , toluene , hydrogen bond , fluorescence , functional group , self assembly , end group , photochemistry , polymer , organic chemistry , molecule , copolymer , physics , quantum mechanics
Abstract Herein, we describe the role of end functional groups in the self‐assembly of amide‐functionalized oligo( p ‐phenylenevinylene) (OPV) gelators with different end‐groups. The interplay between hydrogen‐bonding and π‐stacking interactions was controlled by the bulkiness of the end functional groups, thereby resulting in aggregates of different types, which led to the gelation of a wide range of solvents. The variable‐temperature UV/Vis absorption and fluorescence spectroscopic features of gelators with small end‐groups revealed the formation of 1D H‐type aggregates in CHCl 3 . However, under fast cooling in toluene, 1D H‐type aggregates were formed, whereas slow cooling resulted in 2D H‐type aggregates. OPV amide with bulky dendritic end‐group formed hydrogen‐bonded random aggregates in toluene and a morphology transition from vesicles into fibrous aggregates was observed in THF. Interestingly, the presence of bulky end‐group enhanced fluorescence in the xerogel state and aggregation in polar solvents. The difference between the aggregation properties of OPV amides with small and bulky end‐groups allowed the preparation of self‐assembled structures with distinct morphological and optical features.