A low molecular weight ESIPT-based probe was synthesized and tested for detecting pH, cations, and anions in aqueous solutions. The probe exhibited a good emission in water due to aggregation induced by π-π* stacking. It gave an “off–on” fluorescent response to higher pHs because of blocking the non-radiative ESIPT after deprotonating phenolic hydroxyl groups. Moreover, the fluorescence emission of the probe (water/ethanol = 3:1, pH 10) was quenched only by Cu²⁺ with limit of detection LOD = 3.2 μM. The stoichiometric ratio of the probe/Cu²⁺ complex was found to be 1:1. Furthermore, changes of the probe’s absorption and emission signals (as outputs) in response to the presence of H⁺ and HO^– or Cu²⁺ and Br⁻ stimuli (as chemical inputs) mimics INHIBIT, IMPLICATION and NOT TRANSFER logic gates.

A new water-soluble poly(propylene imine) dendrimer (PPI) modified with 4-sulfo-1,8-naphthalimid units (SNID) and its related structure monomer analog (SNIM) has been prepared by a simple synthesis. The aqueous solution of the monomer exhibited aggregation-induced emission (AIE) at 395 nm, while the dendrimer emitted at 470 nm due to an excimer formation beside the AIE at 395 nm. Fluorescence emission of the aqueous solution of either SNIM or SNID was significantly affected by traces of different miscible organic solvents, and the limits of detection were found to be less than 0.05% (v/v). Moreover, SNID exhibited the function to execute molecular size-based logic gates where it mimics XNOR and INHIBIT logic gates using water and ethanol as inputs and the AIE/excimer emissions as outputs. Hence, the concomitant execution of both XNOR and INHIBIT enables SNID to mimic digital comparators.

New 2-thioxopyrimidin-4-ones capable of participating in regioselective reactions with functionally diverse hydrazonoyl chlorides towards angular regioisomers, rather than linear ones, were designed and synthesized to form stereoisomeric cis- and trans-hexahydro [1,2,4]triazolo[4,3-a]quinazolin-9-ones to be tested as antitumor candidates. The angular regiochemistry of the products was verified through crystallographic experiments and NMR studies. In addition, the regioselectivity of the reaction was found to be independent of the stereochemistry of the used 2-thioxopyrimidin-4-one. Only compound 4c demonstrated satisfactory growth inhibition against all the cancer cells used among all the produced drugs.

A novel diamino triazine based 1,8-naphthalimide (NI-DAT) has been designed and synthesized. Its photophysical properties have been investigated in different solvents and its sensory capability evaluated. The fluorescence emission of NI-DAT is significantly impacted by the solvent polarity due to its inherent intramolecular charge transfer character. Moreover, the fluorescence emission quenched at higher pH as a result of photo-induced electron transfer (PET) from triazine moiety to 1,8-naphthalimide after cleaving hydrogen bonds in the self-associated dimers. Furthermore, the new chemosensor exhibited a good selectivity and sensitivity towards Hg²⁺ among all the used various cations and anions in the aqueous solution of ethanol (5:1, v/v, pH = 7.2, Tampon buffer). NI-DAT emission at 540 nm was quenched remarkably only by Hg²⁺, even in the presence of other cations or anions as interfering analytes. Job’s plot revealed a 2:1 stoichiometric ratio for NI-DAT/Hg²⁺ complex

Regioselective cyclocondensation of 2,4-diacetyl-5-hydroxy-5-methyl-3-(3-nitrophenyl/4-nitrophenyl)cyclohexanones 1a,b with cyanothioacetamide afforded the corresponding 7-acetyl-4-cyano-1,6-dimethyl-6-hydroxy-8-(3- and -4-nitrophenyl)-5,6,7,8-tetrahydrosoquinoline-3(2H)-thiones 2a,b. Reaction of compounds 2a,b with ethyl iodide, 2-chloroacetamide (4a), or its N-aryl derivatives 4b–e in the presence of sodium acetate trihydrate gave 3-ethylthio-5,6,7,8-tetrahydroisoquinoline 3 and (5,6,7,8-tetrahydroisoquinolin-3-ylthio)acetamides 5a–i, respectively. Cyclization of compounds 5b–d,f,g into their isomeric 1-amino-6,7,8,9-tetrahydrothieno[2,3-c]isoquinoline-2-carboxamides 6b–d,f,g was achieved by heating in ethanol containing a catalytic amount of sodium carbonate. Structures of all synthesized compounds were characterized on the basis of their elemental analyses and spectroscopic data. The crystal structure of 5,6,7,8-tetrahydroisoquinoline 5d was determined by X-ray diffraction analysis. In addition, the biological evaluation of some synthesized compounds as anticancer agents was performed, and only six compounds showed moderate to strong activity against PACA2 (pancreatic cancer cell line) and A549 (lung carcinoma cell line). Moreover, the antioxidant properties of most synthesized compounds were examined. The results revealed high antioxidant activity for the most tested compounds.