Coordinated aqua molecules mediated phosphoester cleavage activity of a dimeric gadolinium(III)-acetate Article Swipe
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· 2017
· Open Access
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· DOI: https://doi.org/10.5281/zenodo.5636439
· OA: W4300908370
Department of Chemistry, Raghunathpur College, Purulia-723 133, West Bengal, India <em>E-mail</em> : [email protected], [email protected] Department of Physics, Midnapore College (Autonomous), Midnapore-721 101, West Bengal, India <em>Manuscript received 10 July 2017, accepted 26 August 2017</em> In this present wok, we report the synthesis and X-ray crystallographic characterization of a dimeric gadolinium(III)-acetate, [Gd(OAc)<sub>3</sub> (H<sub>2</sub>O)<sub>2</sub> ]<sub>2</sub> .2H<sub>2</sub>O (1) (OAc = acetate). Single crystal X-ray diffraction study reveals that this gadolinium acetate dimer crystallises in triclinic system with P1 <sup>–</sup> space group and each of the Gd<sup>III</sup> centres in 1 adopts tricapped trigonal prism geometry. The lattice aqua molecules in this dimer form a 8-membered cyclic tetrameric water cluster mediated by 3D crystalline architecture of Gd<sup>III</sup> complex through strong O…H hydrogen bonding interaction along a axis in its crystalline phase and signify its supramolecular aspects in biology. On the other hand, presence of coordinated aqua molecules create considerable interest to investigate the cleavage efficacy of 1 towards phosphoester bond using (p-nitrophenyl)phosphate (pNPP) in aqueous DMF medium. Kinetic experiments for the hydrolytic cleavage of DNA-model pNPP were followed spectrophotometrically following the incremental absorbance at 415 nm under normal conditions at 25 ºC. The hydrolytic cleavage of the phosphodiester bond proceeds with the pseudo-first order initial rate, <em>k</em><sub>obs</sub> = 5.43×10<sup>–4</sup> and 5.38×10<sup>–4</sup> min–1 for 48 h and 24 h respectively, and produces an inorganic phosphate and pnitrophenolate as the final products of hydrolysis. So both types of aqua molecules (lattice and coordinated) have considerable significance on the perspective of material science and biological chemistry.
