Development of new
fluorescent molecules, especially pH-sensitive
fluorescent dyes, is always in high demand due to their wide applications
in various fields and the limited number of common chromophores. In
this work, a family of 3-amino-N-phenylfuro[2,3-b]pyridine-2-carboxamides (AFP) was synthesized
as novel fluorescent compounds. Besides fluorescence in an organic
solvent, AFP 1 and AFP 2 exhibit good fluorescence
properties in both acidic and basic aqueous solution, which could
be explained by protonation or different conformations formed in solution.
Density functional theory (DFT) calculations on the highest occupied
molecular orbital–lowest unoccupied molecular orbital (HOMO-LUMO)
of various conformations were performed for further support.
With the advent of big data and the information age, the data magnitude of various complex networks is growing rapidly. Many real-life situations cannot be portrayed by ordinary networks, while hypergraphs have the ability to describe and characterize higher order relationships, which have attracted extensive attention from academia and industry in recent years. Firstly, this paper described the development process, the application areas, and the existing review research of hypergraphs; secondly, introduced the theory of hypergraphs briefly; then, compared the learning methods of ordinary graphs and hypergraphs from three aspects: matrix decomposition, random walk, and deep learning; next, introduced the structural optimization of hypergraphs from three perspectives: dynamic hypergraphs, hyperedge weight optimization, and multimodal hypergraph generation; after that, the applicability of three uncertain hypergraph models were analyzed based on three uncertainty theories: probability theory, fuzzy set, and rough set; finally, the future research directions of hypergraphs and uncertain hypergraphs were prospected.
The
development of efficient methods for the synthesis of substituted
polycyclic arenes with various topologies is in high demand due to
their excellent electrical and optical properties. In this work, a
series of gem-dimethylcyclopentane-fused arenes with
more than ten topologies were synthesized via a 1,5,7-Triazabicyclo[4.4.0]dec-5-ene
(TBD)-mediated dehydro-Diels–Alder reaction with moderate to
good yields. The introduction of the near-planar gem-dimethylcyclopentane moiety not only impacts the molecular conjugative
system but also regulates the intermolecular π–π
interactions and crystal packing, which are critical for the photoelectric
performance of arenes. The photophysical properties, molecular geometry,
molecular packing of these compounds, and electrochemical properties
were investigated by UV–vis absorption, fluorescence emission
spectra, DFT calculations, single-crystal X-ray structure analysis,
and cyclic voltammetry study.
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