Cubane-like tetranuclear Cu(<scp>ii</scp>) complexes bearing a Cu<sub>4</sub>O<sub>4</sub> core: crystal structure, magnetic properties, DFT calculations and phenoxazinone synthase like activity

Sagar, S.; Sengupta, Swaraj; Mota, Antonio J.; Chattopadhyay, Shyamal Kumar; Ferao, Arturo Espinosa; Rivière, Éric; Lewis, William; Naskar, Subhendu

doi:10.1039/c6dt03754b

Cited by 73 publications

(26 citation statements)

References 65 publications

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“…The activity of 1 as a phenoxazinone synthase mimic was examined by UV/Vis spectrophotometry with o ‐aminophenol (OAP) as the substrate . Firstly, it was important to check whether the present complex could catalyze the oxidation of OAP under aerobic conditions.…”

Section: Resultsmentioning

confidence: 99%

Valence‐Tautomerism‐Driven Aromatic Nucleophilic Substitution in Cobalt‐Bound Tetrabromocatecholate Ligands – Influence of Positive Charge at the Ligand Backbone on Phenoxazinone Synthase Activity

Panja¹,

Frontera

2018

Eur J Inorg Chem

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The mononuclear Co III complex [Co(Br 3 Cat-py) 2 (py) 2 ]-Cl·8H 2 O (1, py = pyridine, Br 3 pyCatH 2 = 3,5,6-tribromo-4-pyridiniumcatechol) was synthesized through the reaction of CoCl 2 ·6H 2 O with tetrabromocatechol in the presence of an excess of pyridine at elevated temperature. The solid-state structure was determined by X-ray crystallography, which disclosed the valence-tautomerism-induced aromatic nucleophilic substitution of the tetrabromocatecholate ligands by pyridine. A cyclic voltammetry study revealed the redox flexibility of both the transition-metal centre and the coordinated redox-active ligand in this complex. Moreover, 1 exhibits moderately strong catalytic activity and mimics the function of phenoxazinone [a] Postgraduate

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Section: Resultsmentioning

confidence: 99%

Valence‐Tautomerism‐Driven Aromatic Nucleophilic Substitution in Cobalt‐Bound Tetrabromocatecholate Ligands – Influence of Positive Charge at the Ligand Backbone on Phenoxazinone Synthase Activity

Panja¹,

Frontera

2018

Eur J Inorg Chem

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“…An attempt was also made to examine the reactivity of the synthesized copper complexes with a comparison of the kinetic parameter for other reported copper complexes. [5,47,56,59,[62][63][64] The kinetics parameter are furnished in Table 2.…”

Section: Catalytic Oxidation Studies Of 2-aminophenol and Mechanistic Inferencesmentioning

confidence: 99%

Copper(II) complexes with a benzimidazole functionalized Schiff base: Synthesis, crystal structures, and role of ancillary ions in phenoxazinone synthase activity

Mudi

Mahato

Joshi

et al. 2021

Applied Organom Chemis

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This research study reports the synthesis, structural characterization and phenoxazinone synthase-like activity of two structurally similar copper(II) complexes developed with a benzimidazole functionalized Schiff base (L). The ligand, L, was designed and synthesized in high yield by the reaction of p-methoxy benzaldehyde with o-phenylenediamine. The reaction of L with CuCl 2 and Cu(NO 3 ) 2 leads to the formation of two isostructural complexes, [Cu(L) 2 Cl 2 ] 2 (1) and [Cu(L) 2 (NO 3 ) 2 ] 2 (2). Single crystal X-ray structural study reveals that both the Cu(II) centre in 1 and 2 adopts a square planar geometry. An attempt has also been made to understand the role of coordinated coligands on the catalytic oxidation of 2-aminophenol (2-AP) to 2-amino-3Hphenoxazine-3-one (2-APX) in methanol. The presence of coordinated nitrate to Cu(II) ions imparts a more labile character to complex 2, and the catalytic efficiency (k cat /K M ) for complex 2 (1.50 × 10 7 ) was determined almost double compared with that of complex 1 (8.78 × 10 6 ). Electro-chemical and electrospray ionization mass spectrometry studies of 1 and 2 with 2-AP suggests that the square planar geometries of the Cu(II) centres remain the driving force to develop enzyme-substrate adducts and excellent catalytic performance of the complexes. Electrochemical and EPR spectral analysis of the reaction mixture confirm the presence of active 2-AP − /2-AP •− redox species in the course of catalytic oxidation and suggest the radical driven oxidative coupling of 2-AP in an aerobic environment. Temperature-dependent kinetic measurements were carried out to evaluate the activation parameters (E a , ΔH ‡ , ΔS ‡ ), which favours the higher rate of catalytic oxidation of 2-AP for complex 2 than complex 1.

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“…Due to simple preparation and diverse structural, they are extensively used in the synthesis of various metal complexes. [ 1 ] They have huge application potential in many fields, for example, excellent property of luminescence, [ 2,3 ] magnetic properties, [ 4 ] clinical trials, [ 5 ] industrial potentials for catalysis, [ 6 ] and green multifunctional lubricating oil additive. [ 7 ] There are numerous reports on the biological activities of Schiff base metal complexes, including their use for anticancer, antibacterial, antifungal, and antioxidant.…”

Section: Introductionmentioning

confidence: 99%

Two dinuclear copper (II) and nickel (II) complexes based on 4‐(diethylamino)salicylaldehyde: X‐ray structures, spectroscopic, electrochemical, antibacterial, Hirshfeld surfaces analyses, and time‐dependent density functional theory calculations

Chai

Zhang

et al. 2020

Applied Organom Chemis

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The quinazoline-type ligand 2-(4-diethylamino-2-hydroxyphenyl)-4-methyl-1,-2-dihydroquinazoline 3-oxide (HL 1 ; H is the deprotonatable hydrogen) was prepared. Two 2-D supramolecular complexes [Cu 2 (L 2) 2 (NO 3) 2 ] (1) and [Ni 2 (L 2) 2 (CH 3 COO) 2 ] (2) (L 2 = 1-(2-{[(E)-(4-diethylamino-2-hydroxybenzylidene] amino} phenyl)ethanone oxime) were synthesized using HL 1 and characterized by elemental analysis, spectroscopic methods, and single-crystal X-ray diffraction studies. It revealed that 1 had coordinated two nitrate ions whereas 2 had acetate ions. In the crystal structures, six-coordinated Cu (II) complex 1 formed an infinite 2-D and X-shaped 3-D supramolecular frameworks. Simultaneously, Ni (II) complex 2 assembled into wavy 2-D networks. Furthermore, electrochemical properties and antimicrobial activities of all compounds were as well investigated. Afterwards, the electrophilic and nucleophilic attack sites identified by electrostatic potential (ESP) calculations confirmed that hydrogen bonds were observed in the optimized structure of the crystal, and the closest contact between the active atoms of both complexes was confirmed through Hirshfeld surface analysis and time-dependent density functional theory (TD-DFT) calculations.

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Cubane-like tetranuclear Cu(ii) complexes bearing a Cu₄O₄ core: crystal structure, magnetic properties, DFT calculations and phenoxazinone synthase like activity

Cited by 73 publications

References 65 publications

Valence‐Tautomerism‐Driven Aromatic Nucleophilic Substitution in Cobalt‐Bound Tetrabromocatecholate Ligands – Influence of Positive Charge at the Ligand Backbone on Phenoxazinone Synthase Activity

Valence‐Tautomerism‐Driven Aromatic Nucleophilic Substitution in Cobalt‐Bound Tetrabromocatecholate Ligands – Influence of Positive Charge at the Ligand Backbone on Phenoxazinone Synthase Activity

Copper(II) complexes with a benzimidazole functionalized Schiff base: Synthesis, crystal structures, and role of ancillary ions in phenoxazinone synthase activity

Two dinuclear copper (II) and nickel (II) complexes based on 4‐(diethylamino)salicylaldehyde: X‐ray structures, spectroscopic, electrochemical, antibacterial, Hirshfeld surfaces analyses, and time‐dependent density functional theory calculations

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Cubane-like tetranuclear Cu(ii) complexes bearing a Cu4O4 core: crystal structure, magnetic properties, DFT calculations and phenoxazinone synthase like activity

Cited by 73 publications

References 65 publications

Valence‐Tautomerism‐Driven Aromatic Nucleophilic Substitution in Cobalt‐Bound Tetrabromocatecholate Ligands – Influence of Positive Charge at the Ligand Backbone on Phenoxazinone Synthase Activity

Valence‐Tautomerism‐Driven Aromatic Nucleophilic Substitution in Cobalt‐Bound Tetrabromocatecholate Ligands – Influence of Positive Charge at the Ligand Backbone on Phenoxazinone Synthase Activity

Copper(II) complexes with a benzimidazole functionalized Schiff base: Synthesis, crystal structures, and role of ancillary ions in phenoxazinone synthase activity

Two dinuclear copper (II) and nickel (II) complexes based on 4‐(diethylamino)salicylaldehyde: X‐ray structures, spectroscopic, electrochemical, antibacterial, Hirshfeld surfaces analyses, and time‐dependent density functional theory calculations

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Cubane-like tetranuclear Cu(ii) complexes bearing a Cu₄O₄ core: crystal structure, magnetic properties, DFT calculations and phenoxazinone synthase like activity