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The intercalation of 2-methyl-4-chlorophenoxyacetic acid (MCPA) herbicide into the interlayer matrix of calcium–aluminium layered double hydroxide (CaAl LDH) host has been successfully done via the co-precipitation method to form CaAl-MCPA nanocomposite, proposing an eco-friendly alternative with an adjusted delivery system for herbicide application. The intercalation process is supported by powder X-ray diffraction analysis with an expanded interlayer spacing from 8.6 to 19.6 Å for nanocomposite pH 13, which is due to the inclusion of larger size anion in the interlayer. Next, the absence of a nitrate peak at 1,326 cm−1 and the presence of a newly formed peak at 1,416 cm−1 in the Fourier transformed infrared spectroscopy analysis also confirmed the process of the intercalation. The significant decrease in nitrogen content to 0.50% indicates the intercalation of MCPA using the carbon, hydrogen, nitrogen, sulphur analyser. The release rate of the MCPA anion in the aqueous solutions is initially rapid, followed by the slow release in the order of phosphate > carbonate > chloride and followed the pseudo-second-order kinetic model. Hence, the conducted studies exhibit the successful intercalation of the MCPA herbicide anion and its controlled release mechanism as a potential hybrid green herbicide.

The conventional herbicide 2-methyl-4-chlorophenoxyacetic acid (MCPA) provide substantial risk to the environment such as contamination of soil and groundwater. The overuse application of conventional herbicide can leave harmful residues in soil and be washed off as runoff, thus causes toxic effect to nontarget organism. For instance, MCPA can cause toxicity to the freshwater organisms such as Daphnia magna and alga Selenastrum capricornutum. Zinc oxide as nanomaterials that are intercalated with 2-methyl-4-chlorophenoxyacetic acid (ZMCPA) herbicide may be useful to resolve the problems associated with MCPA. Nanoherbicide are known to provide a better penetration of active substances hence reduces the amount of herbicide to be applied. The nanostructured herbicide such as ZMCPA could substantially replace the conventional herbicide MCPA if it able to kill the targeted weeds efficiently and have a low risk to the environment. Therefore, it is important to compare the differences of herbicidal activity of MCPA and ZMCPA. The objective of this research is to determine the effects of MCPA and ZMCPA on growth and pigment content of Sphagneticola trilobata. The 2nd objective of this research is to measure the physiological effect and effectiveness of herbicidal activity between the conventional and nanoformulation against Sphagneticola trilobata. The preliminary study was conducted to determine a minimal concentration for MCPA to exert its effect on Sphagneticola trilobata. Then, in the main research, Sphagneticola trilobata was exposed to different concentrations of MCPA and ZMCPA in low, medium and high concentrations. The effect of MCPA and ZMCPA on growth and pigment content of Sphagneticola trilobata was observed at 7, 14 and 21 days, respectively. The results indicated there were no obvious differences in plant growth and pigment content observed between treatment of MCPA and ZMCPA at the same exposure concentration at 7, 14 and 21 days, respectively. MCPA showed higher herbicide efficacy than ZMCPA. [ABSTRACT FROM AUTHOR]

In the title compound, C(14)H(12)ClN(3)S, the dihedral angle between the terminal benzene rings is 56.6 (2)°; the benzene rings lie to the same side of the mol-ecule. The major twist in the mol-ecule occurs around the C(ar)-N bond (ar is aromatic) [C-N-C-C = 49.9 (5)°]. The configuration about the N=C bond [1.271 (4) Å] is E. The amine H atoms lie on opposite sides of the mol-ecule with one forming an intra-molecular N-H⋯N(imine) hydrogen bond and an S(5) ring. In the crystal, centrosymmetric dimers are formed via {⋯HNC=S}(2) synthons.