Polymeric Copper(Ii) Diethylenetriaminepentaacetates For Gas Adsorptions

A series of copper(II) diethylenetriaminepentaacetates [Cu(H(4)dtpa)Cl]center dot KCl center dot 3.5H(2)O (1), K-n[Cu (H(2)dtpa)](n)center dot 2nH(2)O (2), K-3[Cu(dtpa)]center dot 3H(2)O (3) and K-n[Cu-2(dtpa)](n)center dot 4nH(2)O (4) (H(5)dtpa = N,N,N',N '',N ''-diethylenetriamine-pentaacetic acid) have been obtained from the direct reactions of copper(II) chloride with diethylenetriaminepentaacetic acid in acidic or weak acidic solutions. pH values show obvious impacts for the coordination modes of DTPA with the formations of monomer, one dimensional (1D) and three dimensional (3D) structures respectively. The four complexes are well characterized by elemental analysis, IR, X-ray structural analyses and theoretical bond valence calculations. There exist free carboxy and amino groups in 1, which indicates that strong acidity can weaken the coordination of DTPA. Complex 4 is a 3D metal organic framework with small holes of diameter 3.3 angstrom, which can adsorb oxygen for 12.83 mg/g under 29.9 bar. It is thermal stable up to 150 degrees C based on simulated and experimental XRD patterns. (C) 2020 Elsevier Ltd. All rights reserved.