Catecholase activity, DNA cleavage and cytotoxicity of six Zn(II) complexes synthesized from designed Mannich ligands: higher reactivity of mononuclear over dinuclear

Sanyal, Ria; Dash, Sandeep Kumar; Das, Swapan K; Chattopadhyay, Sourav; Roy, Somenath; Das, Debasis

doi:10.1007/s00775-014-1148-z

Cited by 32 publications

(9 citation statements)

References 66 publications

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“…Moreover, Das et al proposed that the conversion of 3,5-DTBC to 3,5-DTBQ can be promoted by the redox-innocent Zn(II) ion via a radical pathway. 25 In this case, the coordinated ligand undergoes reduction with the concomitant oxidation of catechol to form semibenzoquinone.…”

Section: Catechol Oxidase Studies and Kineticsmentioning

confidence: 99%

“…22 Recent investigations have also shown that some manganese(II/III), nickel(II), zinc(II) and cobalt(II/III) species can also mediate such catechol oxidation. [23][24][25][26] It becomes evident that in the case of Ni(II) and Mn(III) metal-centered redox participation is most probably responsible for the catecholase activity of these model compounds whereas in the case of redox innocent Zn(II) this activity can be promoted through the generation of a ligand-centered radical. However, to the best of our knowledge, no mechanistic studies have yet been conducted on the catecholase-like activity of cobalt complexes.…”

Section: Introductionmentioning

confidence: 99%

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Unprecedented structural variations in trinuclear mixed valence Co(ii/iii) complexes: theoretical studies, pnicogen bonding interactions and catecholase-like activities

et al. 2015

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Three new mixed valence trinuclear Co(II/III) compounds cis-[Co3L2(MeOH)2(N3)2(μ1,1-N3)2] (1), trans-[Co3L2(H2O)2(N3)2(μ1,1-N3)2]·(H2O)2 (2) and [Co3L(R)2(N3)3(μ1,3-N3)] (3) have been synthesized by reacting a di-Schiff base ligand (H2L) or its reduced form [H2LR] (where H2L= N,N'-bis(salicylidene)-1,3-propanediamine and H2LR= N,N'-bis(2-hydroxybenzyl)-1,3-propanediamine) with cobalt perchlorate hexahydrate and sodium azide. All three products have been characterized by IR, UV-Vis and EPR spectroscopies, ESI-MS, elemental, powder and single crystal X-ray diffraction analyses. Complex 2 is an angular trinuclear species in which two terminal octahedral Co(III)N2O4 centers coordinate to the central octahedral cobalt(II) ion through μ2-phenoxido oxygen and μ1,1-azido nitrogen atoms along with two mutually cis-oxygen atoms of methanol molecules. On the other hand, in linear trinuclear complex , in addition to the μ2-phenoxido and μ1,1-azido bridges with terminal octahedral Co(III) centres, the central Co(II) is bonded with two mutually trans-oxygen atoms of water molecules. Thus the cis-trans configuration of the central Co(II) is solvent dependent. In complex 3, the two terminal octahedral Co(III)N2O4 centers coordinate to the central penta-coordinated Co(II) ion through double phenoxido bridges along with the nitrogen atom of a terminal azido ligand. In addition, the two terminal Co(III) are connected through a μ1,3-azido bridge that participates in pnicogen bonding interactions (intermolecular N-N interaction) as an acceptor. Both the cis and trans isomeric forms of 1 and 2 have been optimized using density functional theory (DFT) calculations and it is found that the cis configuration is energetically more favorable than the trans one. However, the trans configuration of 2 is stabilized by the hydrogen bonding network involving a water dimer. The pnicogen bonding interactions have been demonstrated using MEP surfaces and CSD search which support the counter intuitive electron acceptor ability of the μ1,3-azido ligand. Complexes 1-3 exhibit catecholase-like activities in the aerial oxidation of 3,5-di-tert-butylcatechol to the corresponding o-quinone. Kinetic data analyses of this oxidation reaction in acetonitrile reveal that the catecholase-like activity follows the order: 1 (kcat = 142 h(-1)) > 3 (kcat = 99 h(-1)) > 2 (kcat = 85 h(-1)). Mechanistic investigations of the catalytic behaviors by X-band EPR spectroscopy and estimation of hydrogen peroxide formation indicate that the oxidation reaction proceeds through the reduction of Co(III) to Co(II).

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Section: Catechol Oxidase Studies and Kineticsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Unprecedented structural variations in trinuclear mixed valence Co(ii/iii) complexes: theoretical studies, pnicogen bonding interactions and catecholase-like activities

et al. 2015

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“…In this case g || is greater than g ⊥ which indicated that in solution the coordination geometry around the metal centre was probably square pyramidal . Addition of 3,5‐DTBC to the solution of complex 1 , an extra peak in EPR spectrum (near g ∼2) was observed which was probably due to the generation of ligand centred radical (shown in Figure S30).…”

Section: Resultsmentioning

confidence: 99%

Water‐Soluble Copper Complex Derived from Ligand TETA^TA Having NNN Donors: Studies on Rapid Degradation of Organic Dyes, Catecholase and Phenoxazinone Synthase Activities

2018

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Water-soluble copper complex [Cu(TETA TA )(Cl 2 )] (1) derived from tridentate ligand (TETA TA ) (L= 2-(2-((2-((2-aminoethyl)amino) ethyl)-amino)ethyl)isoindoline-1,3-dione) having NNN donor, was synthesized, characterized and its molecular structure was determined using X-ray crystallography. This water soluble copper complex was found to be an efficient catalyst for rapid degradation of organic dyes like orange II, rhodamine B and methylene blue dyes were investigated. This catalyst was also utilised for the oxidation of catechol, giving rise to catecholase activity as well as oxidative coupling of 2-aminophenol providing phenoxazinone synthase activity. DFT and TD-DFT calculations were performed to understand the electronic properties of this molecule using B3LYP/LANL2DZ basis set. Results and discussion Synthesis and characterizationMetal complex [Cu(TETA TA )(Cl 2 )](1) was synthesized via template synthesis utilizing CuCl 2 .2H 2 O, N,N'-Bis(2-aminoethyl)ethane-1,2-diamine and phthalic anhydride in methanol (shown in [a] O.

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“…[62][63][64][65][66] Now to rationalize the exact pathway for our complexes we have performed DFT calculation (vide infra). [62][63][64][65][66] Now to rationalize the exact pathway for our complexes we have performed DFT calculation (vide infra).…”

Section: Structural Characterization Reveals Thatmentioning

confidence: 99%

Unique mononuclear Mn^IIcomplexes of an end-off compartmental Schiff base ligand: experimental and theoretical studies on their bio-relevant catalytic promiscuity

et al. 2016

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Three new mononuclear manganese(ii) complexes, namely [Mn(HL)2]·2ClO4 (1), [Mn(HL)(N(CN)2)(H2O)2]·ClO4 (2) and [Mn(HL)(SCN)2] (3) [LH = 4-tert-butyl-2,6-bis-[(2-pyridin-2-yl-ethylimino)-methyl]-phenol], have been synthesized and structurally characterized. An "end-off" compartmental ligand (LH) possesses two symmetrical compartments with N2O binding sites but accommodates only one manganese atom instead of two due to the protonation of the imine nitrogen of one compartment. Although all three complexes are mononuclear, complex 1 is unique as it has a 1 : 2 metal to ligand stoichiometry. The catalytic promiscuity of complexes 1-3 in terms of two different bio-relevant catalytic activities namely catecholase and phenoxazinone synthase has been thoroughly investigated. EPR and cyclic voltametric studies reveal that radical formation rather than metal centered redox participation is responsible for their catecholase-like and phenoxazinone synthase-like catalytic activity. A computational approach suggests that imine bond bound radical generation rather than phenoxo radical formation is most likely responsible for the oxidizing properties of the complexes.

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Catecholase activity, DNA cleavage and cytotoxicity of six Zn(II) complexes synthesized from designed Mannich ligands: higher reactivity of mononuclear over dinuclear

Cited by 32 publications

References 66 publications

Unprecedented structural variations in trinuclear mixed valence Co(ii/iii) complexes: theoretical studies, pnicogen bonding interactions and catecholase-like activities

Unprecedented structural variations in trinuclear mixed valence Co(ii/iii) complexes: theoretical studies, pnicogen bonding interactions and catecholase-like activities

Water‐Soluble Copper Complex Derived from Ligand TETA^TA Having NNN Donors: Studies on Rapid Degradation of Organic Dyes, Catecholase and Phenoxazinone Synthase Activities

Unique mononuclear Mn^IIcomplexes of an end-off compartmental Schiff base ligand: experimental and theoretical studies on their bio-relevant catalytic promiscuity

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Catecholase activity, DNA cleavage and cytotoxicity of six Zn(II) complexes synthesized from designed Mannich ligands: higher reactivity of mononuclear over dinuclear

Cited by 32 publications

References 66 publications

Unprecedented structural variations in trinuclear mixed valence Co(ii/iii) complexes: theoretical studies, pnicogen bonding interactions and catecholase-like activities

Unprecedented structural variations in trinuclear mixed valence Co(ii/iii) complexes: theoretical studies, pnicogen bonding interactions and catecholase-like activities

Water‐Soluble Copper Complex Derived from Ligand TETATA Having NNN Donors: Studies on Rapid Degradation of Organic Dyes, Catecholase and Phenoxazinone Synthase Activities

Unique mononuclear MnIIcomplexes of an end-off compartmental Schiff base ligand: experimental and theoretical studies on their bio-relevant catalytic promiscuity

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Water‐Soluble Copper Complex Derived from Ligand TETA^TA Having NNN Donors: Studies on Rapid Degradation of Organic Dyes, Catecholase and Phenoxazinone Synthase Activities

Unique mononuclear Mn^IIcomplexes of an end-off compartmental Schiff base ligand: experimental and theoretical studies on their bio-relevant catalytic promiscuity