Pyridyl-Amides as a Multimode Self-Assembly Driver for the Design of a Stimuli-Responsive π-Gelator.
An oligo(p-phenylenevinylene) (OPV) derivative connected to pyridyl end groups through an amide linkage (OPV-Py) resulted in a multistimuli-responsive π-gelator. When compared to the corresponding OPV π-gelator terminated by a phenyl-amide (OPV-Ph), the aggregation properties of OPV-Py were found to be significantly different, leading to multistimuli gelation and other morphological properties. The pyridyl moiety in OPV-Py initially interferes with the amide H-bonded assembly and gelation, however, protonation of the pyridyl moiety with trifluoroacetic acid (TFA) facilitated the formation of amide H-bonded assembly leading to gelation, which is reversible by the addition of N,N-diisopropyethylamine (DiPEA). Interestingly, addition of Ag(+) ions to a solution of OPV-Py facilitated the formation of a metallo-supramolecular assembly leading to gelation. Surprisingly, ultrasound-induced gelation was observed when OPV-Py was mixed with a dicarboxylic acid (A1). A detailed study using different spectroscopic and microscopic experimental techniques revealed the difference in the mode of assembly in the two molecules and the multistimuli-responsive nature of the OPV-Py gelation.
Photosciences and Photonics Group, Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (CSIR-NIIST), Trivandrum, 695 019, Kerala, India.
Kalathil K
KK
Kartha
Photosciences and Photonics Group, Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (CSIR-NIIST), Trivandrum, 695 019, Kerala, India.
Vakayil K
VK
Praveen
Photosciences and Photonics Group, Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (CSIR-NIIST), Trivandrum, 695 019, Kerala, India.
Sukumaran Santhosh
SS
Babu
Photosciences and Photonics Group, Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (CSIR-NIIST), Trivandrum, 695 019, Kerala, India.|Academy of Scientific and Innovative Research (AcSIR), CSIR-National Institute for Interdisciplinary Science and Technology (CSIR-NIIST), Trivandrum, 695 019, Kerala, India.
Sandeep
S
Cherumukkil
Photosciences and Photonics Group, Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (CSIR-NIIST), Trivandrum, 695 019, Kerala, India. ajayaghosh@niist.res.in.|Academy of Scientific and Innovative Research (AcSIR), CSIR-National Institute for Interdisciplinary Science and Technology (CSIR-NIIST), Trivandrum, 695 019, Kerala, India. ajayaghosh@niist.res.in.
Ayyappanpillai
A
Ajayaghosh
H-bonding; gels; multistimuli; oligo(p-phenylenevinylene)s; self-assembly