Phenoxazinone synthase and antimicrobial activity by a bis(1,3-diamino-2-propanolate) cobalt(III) complex

Abstract

In this work, we have synthesised and structurally characterized a mononuclear cobalt(III) complex, [Co(2-O-pn) 2 ]Cl. 2H 2 O (1), (2-O-pn = 1,3-diamino-2-propanolate). From the X-ray structure of the cobalt complex, it is revealed that Co(III) ion in 1 adopts an octahedral geometry and crystallizes in the monoclinic system with C2/c space group. The lattice aqua molecule in combination with chloride ion in 1 forms a waterchloride cluster, (H 2 O) 2 ••• (Cl) 2 through strong H-bonding interaction mediated via cobalt(III) complex in a unique binding motif. This cobalt(III) complex has been tested as an effective catalytic system towards the oxidative coupling of 2-aminophenol (2-AP) in the MeCN medium. In situ mass spectral analysis confirms that 2-AP forms an adduct with cobalt ion and the course of catalysis proceeds through catalyst-substrate binding followed by oxidative coupling of 2-AP with iminobenzoquinone. This cobalt(III) catalyst affords exclusively aminophenoxazinone species with a significant turnover number, k cat : 6.37 × 10 2 h −1 in the MeCN medium. This cobalt(III) complex is able to screen out the growth of some bacteria and fungi species. Quantum chemical calculations employing density functional theory is used to model structural parameters and spectroscopic behaviour. The theoretical findings corroborate well with the experimental results.

Synthesis, supramolecular architecture and fluorescence property of a mixed ligand 1D Pb(II) coordination polymer

“…The emission wavelength of Pb(II) polymer at solid state was found as 370 nm (Figure 4). Ligand-to-metal charge transfer (LMCT) may account on this nature of emission [30][31][32][33][34][35]. Previous scientific literature on the Pb(II) polymers also agree with our observation [13].…”

Ligand directed synthesis of a unprecedented tetragonalbipyramidal copper (II) complex and its antibacterial activity and catalytic role in oxidative dimerisation of 2‐aminophenol

“…Switching of the electronic band from 400 nm to 407 nm is a definite signature for the oxidation of 2‐AP in MeCN. [ 13,15,44 ] This spectrophotometric evidence may correspond to the development of aminophenoxazinone species in solution.…”

“…Switching of the electronic band from 400 nm to 407 nm is a definite signature for the oxidation of 2-AP in MeCN. [13,15,44] This spectrophotometric evidence may correspond to the development of aminophenoxazinone species in solution. The kinetics for the oxidative coupling of 2-AP was also carried out to understand the catalytic efficacy of the copper (II) catalyst.…”

“…The growth of oxidation product was monitored at 407 nm as a function of time ( Figure S7). [13,15,37,38,44] The rate constants vs. substrate concentration displayed the nature of kinetics ( Figure S7). The first order saturation kinetics reveals that Michaelis-Menten model seems to be applicable in this case and may be presented according to the following equation 3:…”

Two cobalt metal-organic frameworks constructed from mixed ligands and their magnetic properties

“…Co-based metal-organic frameworks (MOFs) have attracted much attention because of their fascinating architectures, special chemical and physical properties, and potential applications in many fields, such as catalysis, adsorption and separation of gas, magnetic, luminescence and so on. [1][2][3][4][5][6] The judicious choice of the organic ligands are very important for the design and synthesis of MOFs. [7][8][9][10][11] Polycarboxylic acids and polyazo bridged ligands have been extensively employed for constructing MOFs in previous studies.…”