New asymmetric and symmetric 2-((pyridin-4-yl)methylenamino)-3 aminomaleo nitrile and 2,3-bis((pyridin-4-yl)methylenamino)maleonitrile Schiff bases: Synthesis, experimental characterization along with theoretical studies

A new quinoline-based fluorescent-colorimetric chemosensor for sensitive and selective "on-off" detection of Pb2+ ions

For the first time, a novel mono Schiff base of a quinoline-based reversible fluorescent-colorimetric receptor (L) has been designed for the detection of Pb2+ ions in a semi-aqueous medium. The receptor L exhibited a very good selective fluorescent-colorimetric quick on-off response when exposed to Pb2+. The colorimetric assay showed a sensitivity of 1.2 × 10-6 M, while the fluorescent assay exhibited a sensitivity of 9.9 × 10-7 M for Pb2+. A 1 : 1 stoichiometric complexation between L and Pb2+ was determined using ESI-MS spectra and Job's plot measurements. Pb2+ was successfully measured using receptor L in both real samples and in an aqueous solution of the protein bovine serum albumin, as well as in the construction of an INHIBIT-type molecular logic gate.

2,3-Diaminomaleonitrile: A Multifaceted Synthon in Organic Synthesis

2,3-Diaminomaleonitrile (DAMN), a tetramer of hydrogen cyanide, displays weakly basic properties and has reactivity comparable to o-phenylenediamine. It has emerged as a versatile, cheap as well as a readily accessible building block towards the synthesis of a variety of organic compounds. The present review focuses on the applications of 2,3-diaminomaleonitrile for the synthesis of Schiff's base, imidazoles, pyrazines, quinoxolines, benzodiazocines, 1,4-diazepines, purines, pyrimidines, pyrazine-tetrazole hybrids, triazoles, thiadiazole, thiazolidines, porphyrazines, formamidines, 1,3,5-triazepines, pyrrolo[3,4-b][1,4]diazepin-6(3H)-ones, triaza[22]annulenes, pyrrolo[3,4-f][1,3,5]triazepines, spiro compounds, pyrazoles and 2,3-dicyano-5,7-bismethylthieno[3,4-b]pyrazine.

Magnesium porphyrazine with peripheral methyl (3,5-dibromophenylmethyl)amino groups – synthesis and optical properties

Novel magnesium(II) porphyrazine with peripheral methyl(3,5-dibromophenylmethyl)amine groups was synthesized in a multi-step procedure starting from commercially available diaminomaleonitrile. All intermediates and the final macrocycle were characterized using UV–Vis, FT-IR, MS and various NMR techniques. The absorption and emission properties of the macrocycle were evaluated in N,N-dimethylformamide, dimethyl sulfoxide, and dichloromethane. The potential photosensitizing activity was evaluated by assessing the ability of the macrocycle to generate singlet oxygen in dimethyl sulfoxide and N,N-dimethylformamide.