Monday, April 09, 2012

Metal–Organic Frameworks with Phosphotungstate Incorporated for Hydrolytic Cleavage of a DNA-Model Phosphodiester




Five phosphotungstate-incorporated metal–organic frameworks

{[Eu4(dpdo)9(H2O)16PW12O40]}(PW12O40)2·(dpdo)3·Cl3 (1); {ZnNa2(μ-

OH)(dpdo)4(H2O)4[PW12O40]}·3H2O (2); {Zn3(dpdo)7}[PW12O40]2·3H2O (3); and [Ln2H(μ-O)2(dpdo)4(H2O)2][PW12O40]·3H2O (Ln = Ho for 4 and Yb for5) (dpdo = 4,4′-bipyridine-N,N′-dioxide) have been synthesized through a one-step hydrothermal reaction and characterized by elemental analyses, infrared (IR) spectroscopy, photoluminescence, and single-crystal X-ray diffraction (XRD). The structural analyses indicate that 15 display diversity structure from one-dimensional (1D) to three-dimensional (3D) series of hybrids. Kinetic experiments for the hydrolytic cleavage of DNA-model phosphodiester BNPP (bis(p-nitrophenyl)phosphate) were followed spectrophotometrically for the absorbance increase at 400 nm in EPPS (4-(2-hydroxyethyl)piperazine-1-propane sulfonic acid) buffer solution, because of the formation of p-nitrophenoxide with 15 under conditions of pH 4.0 and 50 °C. Ultraviolet (UV) spectroscopy indicate that the cleavage of the phosphodiester bond proceeds with the pseudo-first-order rate constant in the range of 10–7–10–6 s–1, giving an inorganic phosphate and p-nitrophenol as the final products of hydrolysis. The results demonstrate that 15 have good catalytic activity and reusability for hydrolytic cleavage of BNPP.

Qiuxia Han (et al.). Metal–Organic Frameworks with Phosphotungstate Incorporated for Hydrolytic Cleavage of a DNA-Model Phosphodieste. American Chemical Society. Apr 1, 2012. http://pubs.acs.org/doi/full/10.1021/ic202685e

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