We report a rapid, sensitive and selective electrochemical sensor based on pillar[5]arene (CP5) reduced graphene (rGO) nanohybrid-modified glassy carbon electrode CP5-rGO/GCE for the trace detection of methyl parathion (MP) by differential pulse voltammetry (DPV) for the first time. Compared to beta-cyclodextrin (β-CD)-functionalized reduced graphene (rGO)-modified GCE β-CD-rGO/GCE, the proposed CP5-rGO/GCE sensor exhibits excellent electrochemical catalytic activity, rapid response, high sensitivity, good reproducibility and anti-interference ability towards MP. The recognition mechanism of β-CD/MP and CP5/MP was studied by ¹H NMR. The results indicate a higher supramolecular recognition capability between CP5 and MP compared to that between β-CD and MP. The β-CD-rGO and CP5-rGO nano-composites were prepared via a wet chemistry approach. The resulting nano-composites have been characterized by thermogravimetric analysis (TGA), fourier transform infrared spectrometry (FTIR), charge transfer resistance (R_ct) and zeta potential. The CP5-rGO/GCE combines the merits of CP5 and rGO, and is used for quantitative detection of MP. It has a low detection limit of 0.0003 μM (S/N = 3) and a linear response range of 0.001–150 μM for MP. This method has been used to detect MP in soil and waste water samples with satisfactory results. This study provides a promising electrochemical sensing platform and is a promising tool for the rapid, facile and sensitive analysis of MP.

The first examples of unsymmetric coumarin polycatenar liquid crystals consisting of a coumarin central core with 1,2,3-triazole dendritic wings on both sides were synthesized via click reaction. Their properties were investigated using POM, DSC, XRD, SEM, IR, UV-vis spectra and photoluminescence measurements. Such polycatenars can self-assemble into different columnar liquid crystalline phases ranging from p4mm via p2mm to p6mm in their bulk states and into organogels with nanobelt or porous morphologies in different solvents. These polycatenars can exhibit highly fluorescent emission with large Stokes shifts (90–118 nm) in solution and as films. Most interestingly, the photodimerization in both LC and non-LC phases led to the formation of absolutely hexagonal columnar LC phases, while photodimerization in gel states led to the formation of flowerlike or 3D porous morphologies. Either columnar phases or gels with flowerlike or ordered porous morphologies were first observed in coumarin based derivatives.