Kartha Kalathil K, Praveen Vakayil K, Babu Sukumaran Santhosh, Cherumukkil Sandeep, Ajayaghosh Ayyappanpillai
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.
Chem Asian J. 2015 Oct;10(10):2250-6. doi: 10.1002/asia.201500331. Epub 2015 Jun 12.
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.
一种通过酰胺键连接吡啶端基的聚对苯撑乙烯撑（OPV）衍生物（OPV-Py）形成了一种多刺激响应性π-凝胶剂。与相应的以苯酰胺封端的OPV π-凝胶剂（OPV-Ph）相比，发现OPV-Py的聚集性质有显著差异，从而导致多刺激凝胶化和其他形态学性质。OPV-Py中的吡啶部分最初会干扰酰胺氢键组装和凝胶化，然而，用三氟乙酸（TFA）使吡啶部分质子化促进了酰胺氢键组装的形成，进而导致凝胶化，通过加入N,N-二异丙基乙胺（DiPEA）可使其逆转。有趣的是，向OPV-Py溶液中加入Ag(+)离子促进了金属超分子组装的形成，进而导致凝胶化。令人惊讶的是，当OPV-Py与二元羧酸（A1）混合时，观察到了超声诱导的凝胶化。使用不同的光谱和显微镜实验技术进行的详细研究揭示了这两种分子组装模式的差异以及OPV-Py凝胶化的多刺激响应性质。
