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This article discusses a new method for synthesizing spirocyclopentene oxindoles, which are found in natural products and biologically active molecules. The authors describe the synthesis process using lithium bis(trimethylsilyl)amide (LiHMDS) and ring closing metathesis. The yields of the desired compounds ranged from 55% to 88%, with some side products observed in certain cases. The authors provide detailed physical and spectroscopic data for each compound synthesized. The article acknowledges the institutions that provided resources and support for the research. [Extracted from the article]

Multiple emissions have been observed from benzil under different conditions in solutions at room temperature as well as in low temperature glass matrices at 77 K. Low temperature emission has been monitored in rigid matrices frozen under different conditions of illumination. Steady state and time-resolved results together with the ab initio quantum chemical calculations provide, for the first time, the assignments of the different fluorescence bands to the different geometries and/or electronic states of the fluorophore molecule. It is revealed that the skew form of benzil emits from the first (S1) as well as the second excited singlet (S2) states depending on the excitation wavelength, while the relaxed transplanar conformer fluoresces only from the S1 state. The yet unexplored emission band peaking at around 360 nm has been assigned to originate from the S2 state. Ab initio calculations using the density functional theory at B3LYP/6-31G** level corroborate well with the experimental observations. [ABSTRACT FROM AUTHOR]

Multiple emissions of α-naphthil are reported insolution phase at room temperature as well as in ethanol glassymatrix at 77 K, frozen under different conditions of illumination.Steady state and time-resolved fluorometric measurements are undertakento assign the observed emissions to the different species in termsof geometry and electronic states of the fluorophore. The unexploredemission band peaking at ∼423 nm has been ascribed to originatefrom the S2electronic state. Exhaustive experiments revealthat while the trans conformer of α-naphthil gives only theS1emission, the conformation with a geometry close tothe ground state one emits from both S1and S2electronic states depending on the excitation wavelength. [ABSTRACT FROM AUTHOR]

Binding interaction of 3-hydroxyflavone (3HF), a bioactive flavonoid, with calf-thymus DNA (ctDNA) has been explored exploiting various experimental techniques. The dual fluorescence of 3HF resulting from the excited state intramolecular proton transfer (ESIPT) is modified remarkably upon binding with the biomacromolecule. The determined binding constant, fluorescence quenching experiment, circular dichroism (CD) study, comparative binding study with the known intercalative binder ethidium bromide and thermometric experiment relating to the helix melting of ctDNA confirm the groove binding of 3HF with the DNA. This is in contrast to two other members of the flavonoid group, namely, fisetin and quercetin, where the bindings are established to be intercalative. The structural difference of 3HF from the other two probes with respect to the absence/presence of the additional hydroxyl groups is ascribed to be responsible for the difference in the mode of binding.