Comparative structure activity relationship for heterogeneous phosphatase-like catalytic activities of one-dimensional Cu(ii) coordination polymers

Abstract

3) with different coordination environments, was chosen to investigate their potential in heterogeneous catalytic studies for the cleavage of phosphate ester bond. In complexes 1, 2 and 3 the trinuclear copper units are connected by m 2 -O À , m 2 -Cl and m-[O-N-O] bridging modes that leads to the formation of sheet like or stacking layer arrangement of coordination polymers with different metal-metal distance. Moreover these complexes have different donor sites of ligands and exogenous ligands in their coordination environment. Therefore the role of different coordination environments of these complexes was explored for transesterification of DNA model substrate, 2-hydroxypropyl-p-nitrophenylphosphate (HPNP). The reaction between the copper(II)complexes and HPNP was investigated spectrophotometrically to understand mechanistic aspects of phosphate ester bond cleavage in HPNP. Kinetic experiments were performed to determine initial rate of reactions and the activity order follows: 1 > 3 >2. Various structural factors of complexes such as coordinating solvents, mode of bridging and metal-metal distance play a significant role in the catalytic activities. The maximum phosphatase like activity of complex 1 (k cat ¼ 9.6 Â 10 À3 s À1 ) can be attributed to coordinated water molecules, shorter metal-metal distance and exposed metal centers.

Recent Advances in Heterogeneous Catalytic Systems Containing Metal Ions for Phosphate Ester Hydrolysis

“…Hussain et al. used ligands with Schiff bases incorporated in their structure; [92] their strategy was based on the use of homogeneous nickel(II) complexes with phosphatase activity [93] . Coordination polymers ( 21 – 23 ) were synthesised with different copper(II) salts, which allowed the study of different bridge possibilities (μ‐OR, μ‐Cl, and μ‐[NO 3 ]) in catalysts 21 – 23 (Figure 4), resulting in the formation of a layer or stacked layers of coordination polymers with different metal–metal distances.…”

“…[81][82][83][84] Firstly,w ediscuss some coordination polymers, an ew class of heterogeneousc atalysts with various applications, including cyanosilylation reactions, ring-opening catalysis, Knoevenagel condensationr eactions, arylation of nitroarenes,c arbon dioxide conversion, biomimetic catalysis, and cellulose hydrolysis. [85][86][87][88][89][90][91] Hussain et al used ligands with Schiff bases incorporated in their structure; [92] their strategyw as based on the use of homogeneous nickel(II) complexes with phosphatase activity. [93] Coordination polymers (21-23)w ere synthesised with different copper(II) salts, which allowed the study of different bridge possibilities (m-OR, m-Cl, and m-[NO 3 ]) in catalysts 21-23 ( Figure 4), resulting in the formation of al ayer or stacked layers of coordination polymers with different metal-metal distances.…”