Polychlorinated dibenzo-
p
-dioxins (PCDDs), as a class of persistent and highly toxic organic pollutants, have been posing a great threat to human health and the environment. The sensing of these compounds is important but challenging. Here, we report a highly stable zirconium-based metal-organic framework (MOF), Zr
6
O
4
(OH)
8
(HCOO)
2
(CPTTA)
2
(BUT-17) with one-dimensional hexagonal channels and phenyl-rich pore surfaces for the recognition and sensing of two representative PCDDs, 2,3-dichlorodibenzo-
p
-dioxin (BCDD) and 2,3,7,8-tetrachlorodibenzo-
p
-dioxin (TCDD), based on the fluorescence quenching. BUT-17 exhibits high sensing ability with the detection limits as low as 27 and 57 part per billion toward BCDD and TCDD, respectively, and is very selective as well without the interference of similar compounds. The recognition of BUT-17 toward BCDD is demonstrated by single-crystal structure of its guest-loaded phase, in which the fluorescence-quenched complexes form between the adsorbed BCDD molecules and the MOF host through
π-π
stacking and hydrogen bonding interactions.
A highly chemically and thermally stable mesoporous hydrogen-bonded organic framework with a high surface area and a large pore volume has been rationally designed and constructed.
The fluorescence of the two new In(iii)-MOFs is selectively quenched by the fluoroquinolones, including ciprofloxacin, one of the most widely used antibiotics worldwide.
In the present study, a new coamorphous phase (CAP) of bioactive herbal ingredient curcumin (CUR) with high solubilitythe was screened with pharmaceutically acceptable coformers. Besides, to provide basic information for the best practice of physiological and pharmaceutical preparations of CUR-based CAP, the interaction between CUR-based CAP and bovine serum albumin (BSA) was studied at the molecular level in this paper. CAP of CUR and piperazine with molar ratio of 1:2 was prepared by EtOH-assisted grinding. The as-prepared CAP was characterized by powder X-ray diffraction, modulated temperature differential scanning calorimetry, thermogravimetric analysis, Fourier-transform infrared, and solid-state C nuclear magnetic resonance. The 1:2 CAP stoichioimetry was sustained by C═O···H hydrogen bonds between the N-H group of the piperazine and the C═O group of CUR; piperazine stabilized the diketo structure of CUR in CAP. The dissolution rate of CUR-piperazine CAP in 30% ethanol-water was faster than that of CUR; the t values were 243.1 min for CUR and 4.378 min for CAP. Furthermore, interactions of CUR and CUR-piperazine CAP with BSA were investigated by fluorescence spectroscopy and density functional theory (DFT) calculation. The binding constants (K) of CUR and CUR-piperazine CAP with BSA were 10.0 and 9.1 × 10 L mol at 298 K, respectively. Moreover, DFT simulation indicated that the interaction energy values of hydrogen-bonded interaction in the tryptophan-CUR and tryptophan-CUR-piperazine complex were -26.1 and -17.9 kJ mol, respectively. In a conclusion, after formation of CUR-piperazine CAP, the interaction forces between CUR and BSA became weaker.
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