Browsing by Author "Shaikh M. Mobin"

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AIE active piperazine appended naphthalimide-BODIPYs: photophysical properties and applications in live cell lysosomal tracking
(Royal Society of Chemistry, 2019) Bhupendra Kumar Dwivedi; Roop Shikha Singh; Afsar Ali; Vinay Sharma; Shaikh M. Mobin; Daya Shankar Pandey
Piperazine appended naphthalimide-BODIPYs (NPB1-NPB4) exhibiting solvatochromism and aggregation-induced emission with a large Stokes shift (up to 146 nm) have been described. Separation of naphthalimide and BODIPY fluorophores by piperazine in these conjugates creates a donor-acceptor system and induces twisted intramolecular charge transfer, in addition to photoinduced electron transfer. The crucial role of naphthalimide, the alkyl chain length, the piperazine ring, and the solid-state packing on AIE has been extensively investigated by various studies. Superior cell permeability coupled with bio-compatibility of these conjugates offers a unique opportunity for their potential applications in live cell lysosomal tracking. © The Royal Society of Chemistry.
Anticancer Activity of Iridium(III) Complexes Based on a Pyrazole-Appended Quinoline-Based BODIPY
(American Chemical Society, 2017) Rajendra Prasad Paitandi; Sujay Mukhopadhyay; Roop Shikha Singh; Vinay Sharma; Shaikh M. Mobin; Daya Shankar Pandey
A pyrazole-appended quinoline-based 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (L1, BODIPY) has been synthesized and used as a ligand for the preparation of iridium(III) complexes [Ir(phpy)2(L1)]PF6 (1; phpy = 2-phenylpyridine) and [(η5-C5Me5)Ir(L1)Cl]PF6 (2). The ligand L1 and complexes 1 and 2 have been meticulously characterized by elemental analyses and spectral studies (IR, electrospray ionization mass spectrometry, 1H and 13C NMR, UV/vis, fluorescence) and their structures explicitly authenticated by single-crystal X-ray analyses. UV/vis, fluorescence, and circular dichroism studies showed that complexes strongly bind with calf-thymus DNA and bovine serum albumin. Molecular docking studies clearly illustrated binding through DNA minor grooves via van der Waals forces and their electrostatic interaction and occurrence in the hydrophobic cavity of protein (subdomain IIA). Cytotoxicity, morphological changes, and apoptosis have been explored by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and Hoechst 33342 staining. IC50 values for complexes (1, 30 μM; 2, 50 μM) at 24 h toward the human cervical cancer cell line (HeLa) are as good as that of cisplatin (21.6 μM) under analogous conditions, and their ability to kill cancer cells lies in the order 1 > 2. Because of the inherent emissive nature of the BODIPY moiety, these are apt for intracellular visualization at low concentration and may find potential applications in cellular imaging and behave as a theranostic agent. © 2017 American Chemical Society.
Pyrazole appended quinoline-BODIPY based arene ruthenium complexes: their anticancer activity and potential applications in cellular imaging
(Royal Society of Chemistry, 2018) Rajendra Prasad Paitandi; Vinay Sharma; Vishwa Deepak Singh; Bhupendra Kumar Dwivedi; Shaikh M. Mobin; Daya Shankar Pandey
Synthesis of an entirely new series of arene ruthenium complexes [Ru(η6-C6H6)(L1)Cl]PF6, (1), [Ru(η6-C10H14)(L1)Cl]PF6 (2), [Ru(η6-C6H6)(L2)Cl]PF6 (3) and [Ru(η6-C10H14)(L2)Cl]PF6 (4) involving 5-[2-(1H-pyrazol-1-yl)quinoline]-BODIPY (L1) and 5-[6-methoxy-2-(1H-pyrazol-1-yl)quinoline]-BODIPY (L2) was described. The ligands and complexes were thoroughly characterized by various physicochemical techniques and the structures of L1, 1 and 4 were determined by X-ray single crystal analyses. Photo-/ and electrochemical property, DNA binding, cytotoxicity, cellular uptake and apoptotic studies on 1-4 were performed by various methods, while singlet oxygen-mediated cytotoxicity via photo-irradiation by visible light was supported by 1,3-diphenylisobenzofuran titration studies. Binding of the complexes in the minor groove of CT-DNA via van der Waals forces and electrostatic interactions was affirmed by molecular docking studies. In vitro antiproliferative activity and photocytotoxicity of 1-4 were examined against the human cervical cancer cell line (HeLa) which clearly showed that these are extremely photocytotoxic under visible light (400-700 nm, 10 J cm−2; IC50 49.15, 1; 25.18, 2; 15.85, 3; 12.87, 4), less toxic in the dark (IC50 > 100 μM) and preferentially accumulate in the lysosome of the HeLa cells. Further, these complexes behave as a potential theranostic agent and their ability to kill cancer cells under visible light lies in the order 4 > 3 > 2 > 1. © The Royal Society of Chemistry.
Self-assembled copper(II) metallacycles derived from asymmetric Schiff base ligands: Efficient hosts for ADP/ATP in phosphate buffer
(Royal Society of Chemistry, 2015) Amit Kumar; Rampal Pandey; Ashish Kumar; Rakesh Kumar Gupta; Mrigendra Dubey; Akbar Mohammed; Shaikh M. Mobin; Daya Shankar Pandey
Novel asymmetric Schiff base ligands 2-{[3-(3-hydroxy-1-methyl-but-2-enylideneamino)-2,4,6-trimethylphenylimino]-methyl}-phenol (H2L1) and 1-{[3-(3-hydroxy-1-methyl-but-2-enylideneamino)-2,4,6-trimethylphenylimino]-methyl}-naphthalen-2-ol (H2L2) possessing dissimilar N,O-chelating sites and copper(ii) metallacycles (CuL1)4 (1) and (CuL2)4 (2) based on these ligands have been described. The ligands and complexes have been thoroughly characterized by satisfactory elemental analyses, and spectral (IR, 1H, 13C NMR, ESI-MS, UV/vis) and electrochemical studies. Structures of H2L2 and 1 have been unambiguously determined by X-ray single crystal analyses. The crystal structure of H2L2 revealed the presence of two distinct N,O-chelating sites on dissimilar cores (naphthalene and β-ketoaminato groups) offering a diverse coordination environment. Metallacycles 1 and 2 having a cavity created by four Cu(ii) centres coordinated in a homo- and heteroleptic fashion with respective ligands act as efficient hosts for adenosine-5′-diphosphate (ADP) and adenosine-5′-triphosphate (ATP) respectively, over other nucleoside polyphosphates (NPPs). The disparate sensitivity of these metallacycles toward ADP and ATP has been attributed to the size of the ligands assuming diverse dimensions and spatial orientations. These are attuned for π-π stacking and electrostatic interactions suitable for different guest molecules under analogous conditions, metallacycle 1 offers better orientation for ADP, while 2 for ATP. The mechanism of the host-guest interaction has been investigated by spectral and electrochemical studies and supported by molecular docking studies. © The Royal Society of Chemistry 2015.
Swift photoswitching in a binuclear Zn(ii) metallacycle relative to a salen-type ligand
(Royal Society of Chemistry, 2014) Amit Kumar; Rampal Pandey; Rakesh Kumar Gupta; Veenu Mishra; Shaikh M. Mobin; Daya Shankar Pandey
The synthesis, characterization and photoswitching behavior of a new salen type Schiff base N,N′-bis(2-hydroxy-5-phenylazobenzilidene)-2,4,6- trimethylbenzene-1,3-diamine (H2L) and a binuclear zinc(ii) metallacycle [{Zn(L)}2·2H2O] (1) have been described. Both H2L and 1 have been characterized by satisfactory elemental analyses, spectral (FT-IR, 1H, 13C NMR, ESI-MS, electronic absorption, emission) and electrochemical studies. Crystal structures of both H2L and 1 have been authenticated by single crystal X-ray diffraction analyses. These exhibit trans-cis photoisomerization upon exposure to UV light (365 nm) and get back to a more stable trans-form after withdrawal of the light. Electronic absorption, emission, 1H NMR and cyclic voltammetric studies revealed that trans-cis isomerization in metallacycle 1 is rather rapid (∼5.0 s) relative to H2L (∼25 s) which has been supported by theoretical studies (DFT). Relatively fast photoisomerization in 1 compared to H2L is facilitated by a small energy gap between HOMO levels of the trans- and cis-isomers. The percentage trans-cis conversion ratio for both H2L and 1 has been evaluated (55-45, H2L; 60-40%, 1) by 1H NMR studies. This journal is © the Partner Organisations 2014.
Synthesis of mono- and bi-metallic dithiocarboxylate-alkyne complexes from sunlight driven insertion reaction and their antibacterial activity
(2014) Sumanta K. Patel; Vijaylakshmi Tirkey; Sasmita Mishra; Hirak R. Dash; Surajit Das; Madhulata Shukla; Satyen Saha; Shaikh M. Mobin; Saurav Chatterjee
Sunlight driven synthesis, characterization and antibacterial evaluation of cyclopentadienyl based metal-dithiocarboxylate alkyne complexes, [LM(CO) n(η2-S2C)CCR], [{L = η5- C5H5, M = W, R = (η5-C5H 4)Fe(η5-C5H5), n = 2}; {L = η5-C5H5, M = W, R = -C(CH 3)CH2, n = 2}; {L = η5-C5H 5, M = Mo, R = -C(CH3)CH2, n = 2}; {L = η5-C5Me5, M = Fe, R = Ph, n = 1}] (5-8) have been carried out. Reactivity of metal-dithiocarboxylate alkyne complexes towards dicobaltoctacarbonyl were studied to obtain a trimetallic dithiocarboxylate complex (9-11). Structural characterizations of 7 and 8 have been carried out crystallographically and DFT calculation was performed on compound 8 to understand the electronic properties of the complex. © 2013 Elsevier B.V. All rights reserved.