A monopyrrolotetrathiafulvalene based naphthalimide tailored organogelator with stimuli responsive properties and absorption for rhodamine B

Abstract

A novel 1,8-naphthalimide functionalized monopyrrolotetrathiafulvalene (MPTTF) derivative had been established as a low molecular weight supramolecular gelator. Supramolecular organogels could be obtained in solvents with different polarity through the heating-cooling process. Further addition of 7,7,8,8-tetracyanoquino-dimethane (TCNQ) to the supramolecular gel systems via the electron donor-acceptor interaction between the MPTTF and TCNQ, especially in polar solvents, could fabricate charge-transfer (CT) complex gels at relatively lower critical gelation concentrations. Interestingly, the self-assembly mode of the CT complexes was closely related to the type of solvents. As expected, due to the dynamic and reversible nature of the non-covalent interactions, the resultant gels exhibited external stimuli-responsiveness to different parameters, including temperature, chemical redox reagent and acid-base. However, the redox stimulus response of the gels depended on the polarity of the solvents, and the reversible gel-sol transformation could be achieved in nonpolar solvent, such as benzene. Moreover, the prepared gels showed irreversible gel-sol transitions on successively triggering with trifluoroacetic acid and triethylamine unless washed with water. Importantly, the original and CT complex gels could effectively remove the cationic rhodamine B dye from water.