A competent and highly discriminating one-pot method for the synthesis of biologically active novel spiro-indenoquinoxaline pyrrolizines accumulating three pharmocophoric cores, heterocyclic quinoline scaffold, pyrrolizines and indeno-quinoxaline, in a single molecular framework by means of a four-component reaction between ninhydrin, o-phenylenediamine, L-proline and quinolinyl chalcones in methanol via [3+2] cycloaddition was developed. The structures of the compounds were well characterized by FT-IR, NMR, ESI-MS, XRD and elemental analysis. The synthesized compounds were screened for in vitro antioxidant activity using DPPH, nitric oxide, super oxide radical and in vitro cytotoxic activity against MCF-7 and A-549 cancer cell lines and visualized using the fluorescent microscopic technique. The newly synthesized compounds exhibited excellent antioxidant activity compared to the standard molecule, i.e., BHT. In terms of cytotoxic activity, compounds 5c, 5e, 6c and 6e were found to exhibit significant activity, when compared to standard doxorubicin against MCF-7 and A-549 cancer cells using the MTT assay method. The cell morphology analysis clearly indicates cell death was induced by apoptosis and necrosis pathways. Molecular docking studies were performed using an EGFR inhibitor to determine the molecular interactions between the compounds and proteins.

Design and development of multifunctional materials have drawn incredible attraction in recent years. Herein, we report the design and construction of versatile star-shaped intramolecular charge transfer (ICT)-coupled excited-state intramolecular proton transfer (ESIPT)-active mechanoresponsive and aggregation-induced emissive (AIE) luminogen triaminoguanidine-diethylaminophenol (LH₃) conjugate from simple precursors triaminoguanidine hydrochloride and 4-(N,N-diethylamino)salicylaldehyde. Solvent-dependent dual emission in nonpolar to polar protic solvents implies the presence of ICT-coupled ESIPT features in the excited state. Aggregation-enhanced emissive feature of LH₃ was established in the CH₃CN/water mixture. Furthermore, this compound exhibits mechanochromic fluorescence behavior upon external grinding. Fluorescence microscopy images of pristine, crystal, and crushed crystals confirm the naked-eye mechanoresponsive characteristics of LH₃. In addition, LH₃ selectively sensed a Cu²⁺ ion through a colorimetric and fluorescence “turn-off” route, and subsequently, the LH₃-Cu²⁺ ensemble could act as a selective and sensitive sensor for S^2– in a “turn-on” fluorescence manner via a metal displacement approach. Reversible “turn-off–turn-on” features of LH₃ with Cu²⁺/S^2– ions were efficiently demonstrated to construct the IMPLICATION logic gate function. The Cu²⁺/S^2–-responsive sensing behavior of LH₃ was established in the paper strip experiment also, which can easily be characterized by the naked eye under daylight as well as a UV lamp (λ = 365 nm).

3-(7-(Diethylamino)-2-oxo-2H-chromen-3-yl)-1-(4-phenylthiazol-2-yl)-1H-pyrazol-5(4H)-one (COPYR) was competently synthesized from methyl 3-(7-(diethylamino)-2-oxo-2H-chromen-3-yl)-3-oxopropanoate and 2-hydrazino-4-phenyl thiazole. The interactions of receptor COPYR with various ions were investigated through absorption and steady-state fluorescence spectral studies, respectively. The results reveal that the complexation of Cr³⁺ ions with COPYR results in 1:1 stoichiometry, which resulted in a quick color response from fluorescent green to colorless with significant quenching of fluorescence at 506 nm in dimethyl sulfoxide medium. Theoretical calculations (density functional theory) confirm the photophysical changes such as absorbance and emission spectral changes. Furthermore, the confocal imaging of A-549 cells clearly points out that the synthesized probe COPYR could be applied for detecting Cr³⁺ in living cells.