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Paciotti R, Chiavarino B, Coletti C, Scuderi D, Re N, Corinti D, Rotari L, Fornarini S, Crestoni ME. IRMPD Spectroscopy of Bare Monodeprotonated Genistein, an Antioxidant Flavonoid. ACS OMEGA 2022; 7:19535-19544. [PMID: 35721943 PMCID: PMC9202291 DOI: 10.1021/acsomega.2c01236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 05/17/2022] [Indexed: 05/11/2023]
Abstract
Genistein is a naturally occurring polyphenol belonging to the family of flavonoids with estrogenic properties and proven antioxidant, anti-inflammatory, and hormonal effects. Genistein and its derivatives are involved in radical scavenging activity by way of mechanisms based on sequential proton-loss electron transfer. In view of this role, a detailed structural characterization of its bare deprotonated form, [geni-H]-, generated by electrospray ionization, has been performed by tandem mass spectrometry and infrared multiple photon dissociation (IRMPD) spectroscopy in the 800-1800 cm-1 spectral range. Quantum chemical calculations at the B3LYP/6-311+G(d,p) level of theory were carried out to determine geometries, thermochemical data, and anharmonic vibrational properties of low-lying isomers, enabling to interpret the experimental spectrum. Evidence is gathered that the conjugate base of genistein exists as a single isomeric form, which is deprotonated at the most acidic site (7-OH) and benefits from a strong intramolecular H-bond interaction between 5-OH and the adjacent carbonyl oxygen in the most stable arrangement.
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Affiliation(s)
- Roberto Paciotti
- Dipartimento
di Farmacia, Università G. D’Annunzio
Chieti-Pescara, Via dei Vestini 31, Chieti I-66100, Italy
| | - Barbara Chiavarino
- Dipartimento
di Chimica e Tecnologie del Farmaco, Università
di Roma “La Sapienza”, Piazzale Aldo Moro, 5, I-00185 Roma, Italy
| | - Cecilia Coletti
- Dipartimento
di Farmacia, Università G. D’Annunzio
Chieti-Pescara, Via dei Vestini 31, Chieti I-66100, Italy
| | - Debora Scuderi
- Institut
de Chimie Physique (UMR8000), CNRS, Université Paris-Saclay, 91405 Orsay, France
| | - Nazzareno Re
- Dipartimento
di Farmacia, Università G. D’Annunzio
Chieti-Pescara, Via dei Vestini 31, Chieti I-66100, Italy
| | - Davide Corinti
- Dipartimento
di Chimica e Tecnologie del Farmaco, Università
di Roma “La Sapienza”, Piazzale Aldo Moro, 5, I-00185 Roma, Italy
| | - Lucretia Rotari
- Dipartimento
di Chimica e Tecnologie del Farmaco, Università
di Roma “La Sapienza”, Piazzale Aldo Moro, 5, I-00185 Roma, Italy
| | - Simonetta Fornarini
- Dipartimento
di Chimica e Tecnologie del Farmaco, Università
di Roma “La Sapienza”, Piazzale Aldo Moro, 5, I-00185 Roma, Italy
| | - Maria Elisa Crestoni
- Dipartimento
di Chimica e Tecnologie del Farmaco, Università
di Roma “La Sapienza”, Piazzale Aldo Moro, 5, I-00185 Roma, Italy
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Li B, Geoghegan BL, Wölper C, Cutsail GE, Schulz S. Redox Activity of Noninnocent 2,2'-Bipyridine in Zinc Complexes: An Experimental and Theoretical Study. ACS OMEGA 2021; 6:18325-18332. [PMID: 34308063 PMCID: PMC8296587 DOI: 10.1021/acsomega.1c02201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 05/18/2021] [Indexed: 06/13/2023]
Abstract
We report on a systematical reactivity study of β-diketiminate zinc complexes with redox-active 2,2'-bipyridine (bpy). The reaction of LZnI (L = HC[C(Me)N(2,6-iPr2C6H3)]2) with NaB(C6F5)4 in the presence of bpy yielded [LZn(bpy)][B(C6F5)4] (1), with bpy serving as a neutral ligand, whereas reduction reactions of LZnI with 1 or 2 equiv of KC8 in the presence of bpy gave the radical complex LZn(bpy) (2) and [2.2.2-Cryptand-K][LZn(bpy)] (3), in which bpy either acts as a π-radical anion or a diamagnetic dianion, respectively. The paramagnetic nature of 2 was confirmed via solution magnetic susceptibility measurements, and UV-vis spectroscopy shows that 2 exhibits absorption bands typical for bpy radical species. The EPR spectra of 2 and its deuterated analog 2-d 8 demonstrate that the spin density is localized to the bpy ligand. Density functional theoretical calculations and natural bond orbital analysis were employed to elucidate the electronic structure of complexes 1-3 and accurately reproduced the structural experimental data. It is shown that reduction of the bpy moiety results in a decrease in the β-diketiminate co-ligand bite angle and elongation of the Zn-N(β-diketiminate) bonds, which act cooperatively and in synergy with the bpy ligand by decreasing Zn-N(bpy) bond lengths to stabilize the energy of the LUMO.
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Affiliation(s)
- Bin Li
- Institute
for Inorganic Chemistry and Center for Nanointegration Duisburg-Essen
(CENIDE), University of Duisburg-Essen, Universitätsstraße 5−7, 45117 Essen, Germany
| | - Blaise L. Geoghegan
- Institute
for Inorganic Chemistry and Center for Nanointegration Duisburg-Essen
(CENIDE), University of Duisburg-Essen, Universitätsstraße 5−7, 45117 Essen, Germany
- Max
Planck Institute for Chemical Energy Conversion (CEC), Stiftstraße 34−36, 45470 Mülheim an der Ruhr, Germany
| | - Christoph Wölper
- Institute
for Inorganic Chemistry and Center for Nanointegration Duisburg-Essen
(CENIDE), University of Duisburg-Essen, Universitätsstraße 5−7, 45117 Essen, Germany
| | - George E. Cutsail
- Institute
for Inorganic Chemistry and Center for Nanointegration Duisburg-Essen
(CENIDE), University of Duisburg-Essen, Universitätsstraße 5−7, 45117 Essen, Germany
- Max
Planck Institute for Chemical Energy Conversion (CEC), Stiftstraße 34−36, 45470 Mülheim an der Ruhr, Germany
| | - Stephan Schulz
- Institute
for Inorganic Chemistry and Center for Nanointegration Duisburg-Essen
(CENIDE), University of Duisburg-Essen, Universitätsstraße 5−7, 45117 Essen, Germany
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Mohapatra RK, Saikishore VP, Azam M, Biswal SK. Synthesis and physicochemical studies of a series of mixed-ligand transition metal complexes and their molecular docking investigations against Coronavirus main protease. OPEN CHEM 2020. [DOI: 10.1515/chem-2020-0190] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
AbstractA novel series of mixed-ligand complexes of the type, [M(L1)(L2)Cl]·2H2O [L1 = 2-(α-methyl salicylidene hydrazine) benzimidazole (primary ligand), L2 = 2,2′-bipyridine (bipy; secondary ligand), M = Co(ii), Ni(ii), Cu(ii) and Zn(ii)], were based on the physicoanalytical studies. The spectroscopic findings revealed tridentate nature of the Schiff base ligand (L1) and its coordination to the metal ions via azomethine nitrogen, ring nitrogen and the deprotonated phenolic oxygen atoms. Furthermore, the synthesized compounds were evaluated for antimicrobial activity against Bacillus subtilis, Escherichia coli and Salmonella typhi microorganisms. In addition, molecular docking studies were carried out against Middle East respiratory syndrome coronavirus (PDB ID: 4ZS6) and severe acute respiratory syndrome coronavirus 2 main protease (PDB ID: 6W63).
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Affiliation(s)
- Ranjan K. Mohapatra
- Department of Chemistry, Government College of Engineering, Keonjhar, Odisha, India
| | - V. P. Saikishore
- Department of Chemistry, Centurion University of Technology and Management, Odisha, India
| | - Mohammad Azam
- Department of Chemistry, College of Science, King Saud University, Riyadh PO BOX 2455, Riyadh 11451, Saudi Arabia
| | - Susanta K. Biswal
- Department of Chemistry, Centurion University of Technology and Management, Odisha, India
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Saha A, Rajput A, Gupta P, Mukherjee R. Probing the electronic structure of [Ru(L 1) 2] Z ( z = 0, 1+ and 2+) (H 2L 1: a tridentate 2-aminophenol derivative) complexes in three ligand redox levels. Dalton Trans 2020; 49:15355-15375. [PMID: 33135029 DOI: 10.1039/d0dt03074k] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Aerobic reaction between [RuII(DMSO)4Cl2], a redox-active 2-aminophenol-based ligand (H2L1: 2-[2-(benzylthio)phenylamino]-4,6-di-tert-butylphenol) and Et3N in MeOH under refluxing conditions afforded a purple complex [Ru(L1)2] (S = 0). Structural analysis reveals that the tridentate ligand coordinates in a mer conformation providing a distorted octahedral RuN2O2S2 coordination. Cyclic voltammetry on 1 in CH2Cl2 reveals the accessability of the monocation, dication and monoanion forms. Reddish purple monocation [Ru(L1)2](PF6)·CH2Cl2 ([1OX1](PF6)·CH2Cl2; S = 1/2) and green dication [Ru(L1)2](BF4)2·H2O ([1OX2](BF4)2·H2O; S = 0) have been isolated through the chemical oxidation of 1 in CH2Cl2 by [FeIII(η5-C5H5)2](PF6) and AgBF4, respectively. A structural analysis of the single crystals of the monocation and the dication with the compositions [1OX1](PF6)·CH2Cl2·H2O (2) and [1OX2](BF4)2·1.7H2O (3), respectively, has been done. Metrical (metal-ligand and ligand backbone) parameters, values of metrical oxidation states of coordinated ligands, 1H NMR spectra of 1 and [1OX2](BF4)2·H2O, EPR spectra of [1OX1](PF6)·CH2Cl2, X-ray photoelectron and UV-VIS-NIR spectra of 1-3, spin population analysis from broken-symmetry (BS) density functional theory (DFT) calculations and quasi-restricted orbital (QRO) analysis have allowed us to assign the electronic structure of the complexes. The complexes exhibit highly covalent metal-ligand interactions. The electronic states of 1, [1OX1]1+ and [1OX2]2+ are best described as [RuII{(LISQ)˙-}2] ↔ [RuIII{(LAP)2-}{(LISQ)˙-}] (S = 0), [RuIII{(LISQ)˙-}2]1+ (S = 1/2) and [RuII{(LIBQ)0}2]2+ ↔ [RuIII{(LISQ)˙-}{(LIBQ)0}]2+ (S = 0), respectively. Notably, all redox processes are ligand-centred. Absorption spectral properties have been rationalized based on time-dependent (TD)-DFT calculations. For 1, the appearance of an IVCT band at 1100 nm supports its Class II-III (borderline) ligand-based mixed-valence character.
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Affiliation(s)
- Anannya Saha
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741 246, India
| | - Amit Rajput
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208 016, India. and Department of Chemistry, School of Basic and Applied Sciences, G. D. Goenka University, Sohna Road, Gurugram 122 103, Haryana, India
| | - Puneet Gupta
- Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247 667, India
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Synthesis, structural, spectral studies, and DFT calculations of a series of mixed ligand complexes of a tridentate N, N, S pyrazole based aldimine and 2,2′-bipyridine. The first example of structurally characterized dimeric cadmium(II) adduct with unusual μ2-Osulfonamido bridges. Polyhedron 2020. [DOI: 10.1016/j.poly.2020.114763] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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