Articles written in Journal of Chemical Sciences
Volume 127 Issue 4 April 2015 pp 649-661 Regular Articles
Synthesis and bio-catalytic activity of isostructural cobalt(III)-phenanthroline complexes
Dhananjay Dey Arnab Basu Roy Anandan Ranjani Loganathan Gayathri Saravanan Chandraleka Dharumadurai Dhanasekaran Mohammad Abdulkader Akbarsha Chung-Yu Shen Hui-Lien Tsai Milan Maji Niranjan Kole Bhaskar Biswas
We have synthesized two isostructural mononuclear cobalt(III) complexes [
Volume 128 Issue 11 November 2016 pp 1755-1764 Regular Article
Recognition of self-assembled water-nitrate cluster in a Co(III)-2,2'-bipyridine host: Synthesis, X-ray structure, DNA cleavage, molecular docking and anticancer activity
SUBRATA DAS ANANDAN RANJANI LOGANATHAN GAYATHRI SUBHASISH SAHA JORGE PASAN DHARUMADURAI DHANASEKARAN MOHAMMAD ABDULKADER AKBARSHA MILAN MAJI BHASKAR BISWAS
A mononuclear cobalt(III) complex [Co(bpy)₂Cl₂]NO₃·2H₂O (1) (bpy = 2,2'-bipyridine) has been synthesized and crystallographically characterized. Self-assembly of the lattice water molecules from rectangular tetrameric water cluster interacts with nitrate anion along the c-axis forming a six membered hexagonal water-nitrate cluster. It presents a new mode of association of water molecules with nitrate molecules which is not predicted theoretically or found experimentally. The molecule effectively cleaves bacterial genomic DNA and shows important cytotoxicity against human hepatocarcinoma cell (HepG2).
Volume 128 Issue 11 November 2016 pp 1775-1782 Regular Article
Unprecedented hetero-geometric discrete copper(II) complexes: Crystal structure and bio-mimicking of Catecholase activity
ABHRANIL DE DHANANJAY DEY HARE RAM YADAV MILAN MAJI VINAYAK RANE R M KADAM ANGSHUMAN ROY CHOUDHURY BHASKAR BISWAS
An unprecedented solid of coper(II) complexes [Cu(dpa)₂NCS]₂[Cu(dpa)₂(NCS)₂](ClO₄)₂ (1) [dpa = 2,2'-dipyridylamine; SCN = thiocyanate], has been synthesized and crystallographically characterized with the aim to study the catecholase activity. The Cu(II) complex mimics the full catalytic cycle of the active site of catechol oxidase enzyme in acetonitrile medium with a turnover number of 4.788 × 10³ h⁻¹ along with the production of semiquinone radical and hydrogen peroxide. In situ generation of Cu(I) species in the catalytic pathway of catechol oxidation was established by electrochemical study and further confirmed by electron paramagnetic resonance (EPR) spectroscopy.
Volume 129 Issue 10 October 2017 pp 1513-1520 REGULAR ARTICLE
Synthesis and phosphatase activity of a Cobalt(II) phenanthroline complex
MAMONI GARAI DHANANJAY DEY HARE RAM YADAV MILAN MAJI ANGSHUMAN ROY CHOUDHURY BHASKAR BISWAS
A mononuclear cobalt(II) complex, [Co(phen) ₂Cl 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 amonoclinicsystem 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 kcat value of 3.78 × 10 ²h ⁻¹.
Volume 129 Issue 10 October 2017 pp 1627-1637 REGULAR ARTICLE
Catalytic aspects of a copper(II) complex: biological oxidase to oxygenase activity
BISWAJIT CHOWDHURY MILAN MAJI BHASKAR BISWAS
A coper(II) complex, [Cu(dpa)2(OAc)](ClO4) (1) [dpa =2, 2'-dipyridylamine; OAc = acetate], has been synthesized and crystallographically characterized. X-ray structure analysis revealed that this mononuclear Cu(II) complex crystallizes as a rare class of hexa coordination geometry named bicapped square pyramidalgeometry with P2₁/c space group. This copper complex displays excellent catalytic efficiency, kcat /KM (h⁻¹) = 6.17 × 10⁵ towards the oxidative coupling of 2-aminophenol (2-AP) to aminophenoxazin-3-one. Further, upon stoichiometric addition of copper(II) complex to 3,5-DTBC in presence of molecular oxygen in ethanol medium, the copper complex affords predominantly extradiol cleavage products along with a small amount of benzoquinone and a trace amount of intradiol cleavage products at a rate, kobs = 1.09 × 10⁻³ min ⁻¹, which provide substantial evidence for the oxygen activation mechanism. This paper presents a novel addition of a copper(II) complex having the potential to mimic the active site of phenoxazinone synthase and catechol dioxygenase enzymes with significant catalytic efficiency.
Volume 135, 2023
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