Synthesis, Characterization of Some Conductive Aromatic Polyamides/Fe3O4 NPs/ITO, and Their Utilization for Methotrexate Sensing

Abstract

Here, we have synthesized four series of polyamide-conductive polymers and used them to modify Fe3O4 NPs/ITO electrodes. The ability of the modified electrodes to detect methotrexate (MTX) anticancer drug electrochemically was investigated. Synthesis of the target-conducting polyamides, P1a–d, P2a–d, P3a, P3b, P3d, and P4c-d, based on different aromatic moieties, such as ethyl 4-(2-(4H-pyrazol-4-ylidene)hydrazinyl)benzoate, diphenyl sulfone, diphenyl ether or phenyl, has been achieved. They were successfully prepared in good yield via solution–polycondensation reaction of the diamino monomers with different dicarboxylic acid chlorides in the presence of N-methyl-2-pyrrolidone (NMP) as a solvent and anhydrous LiCl as a catalyst. A model compound 4 was synthesized from one mole of ethyl-4-(2-(3, 5-diamino-4H-pyrazol-4-ylidene)hydrazinyl) benzoate (diamino monomer) (3) with two moles benzoyl chloride. The structure of the synthesized monomers and polymers was confirmed by elemental and spectral analyses. In addition, thermogravimetric analysis evaluated the thermal stabilities of these polyamides. Furthermore, the morphological properties of selected polyamides were examined using an scanning electron microscope. Polyamide/Fe3O4/ITO electrodes were prepared, and the electrochemical measurements were performed to measure the new polyamides’ conductivity and to detect the MTX anticancer drug in phosphate buffer saline using cyclic voltammetry. The polyamides (P3b and P4b)/Fe3O4/ITO electrodes showed the highest sensitivity and reversibility towards MTX.

Unprecedented ROP of quinazolinones to polyacylamidines using a cesium catalyst

“…The carbonyl (CO) stretching vibration of the monomer 2a appeared at 1662 cm −1 and for the polymer shifted to 1705 cm −1 , indicating the involvement of CO groups in the hydrogen bonding in the polyamide structure. 33 Gel permeation chromatography (GPC) was used to establish the molecular weight of the polymer, and revealed the formation of a polymer with two different chain lengths, having M n values of 12.0 and 5.4 kDa and hence indicating an average degree of polymerization ( D p ) of 78.2 (entry 1, Table 1). Thereafter, experiments were carried out at an elevated temperature of 65 °C and the samples were collected at intervals of two, four, and six hours for analysis.…”