Synthesis and phosphatase activity of a Cobalt(II) phenanthroline complex

Abstract

A mononuclear cobalt(II) complex, [Co(phen) 2 Cl 2 ], (phen = 1,10-phenanthroline) has been synthesized and structurally characterized by different spectroscopic methods including single crystal X-ray structural study. X-ray crystal structural analysis revealed that the cobalt(II) complex crystallizes in a monoclinic system with C2/c space group and exists in cis-configuration in its crystalline state. Room temperature magnetic measurement accounts for 3e paramagnetism and indicates high spin cobalt(II) in the solid state. The cobalt(II) complex has been evaluated as a functional model for phosphatase enzyme by using 4-nitrophenylphosphate (PNPP) as a standard substrate in aqueous DMF medium. This mononuclear cobalt(II) complex exhibits good hydrolytic phosphoester cleavage efficiency with k cat value of 3.78 × 10 2 h −1 .

A Water‐Rich Cobalt(II) Compound: Hydrothermal Synthesis, Spectroscopic, Thermal, Crystal Structure Characterization and Antimicrobial Properties

“…UV‐Vis spectrum of 1 in methanol showedthree characteristic bands at 205, 227 and 265 nm which were assigned to the ligand‐ centered (LC) π→π* or n→π* transitions originating from the metal‐bound phen and (ppda) 2− chromophores (Figure S2). [36,38–40] . A weak intensity band appearing as a shoulder at 315 nm could be assigned to the metal‐ligand or ligand‐ligand charge transfer.…”

“…. [36,[38][39][40] A weak intensity band appearing as a shoulder at 315 nm could be assigned to the metal-ligand or ligandligand charge transfer. The origin of visible spectra for cobalt(II) compounds may be due to spin-orbit coupling, vibrational or low symmetry components, and contribution of these parameters lead to difficulties in the total spectral analyses of cobalt(II) complexes.…”

“…4 T 1g (P) transition arising from the 3d 7 cobalt(II) center (vide infra). [35,38,[41][42][43] The solid-state fluorescence emission spectrum of 1 obtained by both methods were recorded to understand emission properties of 1 at an excitation of 300 nm and were compared with the constituting free co-ligands H 2 ppda and phen. The emission bands for H 2 ppda appear at 407 and 430 nm were attributed to the intra-ligand π*!n or π*!π energy transitions (Figure S3).…”

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

“…For example, the half‐life for the hydrolysis of dimethylphosphate is estimated to be 130 000 years [15] . Approaches that use photolytic degradation by sunlight [16] and biological pathways, [17] as well as their hydrolysis by biomimetic compounds, have been employed to solve the problem of the natural persistence of such compounds [18–30] . The use of biomimetic compounds offers a number of advantages, including the possibility to immobilise these compounds on the surface of insoluble solid matrices for easier handling and reuse [31] …”

“…[15] Approaches that use photolytic degradationb ys unlight [16] and biological pathways, [17] as well as their hydrolysis by biomimetic compounds, have been employed to solve the problem of the natural persistence of such compounds. [18][19][20][21][22][23][24][25][26][27][28][29][30] The use of biomimetic compounds offers a number of advantages, including the possibility to immobilise these compounds on the surface of insoluble solid matrices for easier handling and reuse. [31] Compared with extensivelys tudied homogeneousc atalysts that hydrolyse diverse phosphoester bonds, [28,[32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50] far fewer heterogeneous systemst hat catalyse the cleavage of such bonds have been developed.…”