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In Silico Investigation of the Mechanism of Disulfide Bond Dissociation by New Frustrated Lewis Pairs. J Phys Chem A 2024; 128:97-106. [PMID: 38149919 DOI: 10.1021/acs.jpca.3c06351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2023]
Abstract
Understanding the mechanism of disulfide bond cleavage is important in various scientific disciplines including organic synthesis, catalysis, and biochemistry. In this study, an in silico investigation has been carried out for the dissociation of disulfide bonds using newly designed frustrated Lewis pairs (FLPs). The study revealed that the cleavage of the disulfide bond by the FLP P(tBu)3/B(C2NBSHF2)3 can also be used like the conventional FLP (tBu)3P/B(C6F5)3. It has been observed that the reaction is almost thermoneutral in the gas phase but exothermic in nonpolar solvents, such as toluene, heptane, and hexane. Furthermore, the natural bond orbital (NBO) describes insights into the role of FLPs in facilitating this reaction. Additionally, reaction force and force constant studies shed light on the energy requirements for completing the reaction and the synchronous nature of the dissociation process, respectively. Reaction electronic flux (REF) and its separations give the pattern of electronic activity during the chemical reaction. Extended transition state-natural orbitals for chemical valence (ETS-NOCV) and principal interacting orbital (PIO) analysis provide valuable information about the orbital interactions during the chemical reaction.
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Comparative outcome of single versus two double-pigtail stents for endoscopic drainage of pancreatic fluid collections with minimal necrosis: a retrospective analysis. Acta Gastroenterol Belg 2024; 87:1-5. [PMID: 38431784 DOI: 10.51821/87.1.12118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/05/2024]
Abstract
Background Endoscopic ultrasound (EUS)-guided cystogastrostomy is the treatment of choice for managing symptomatic pancreatic fluid collections (PFC). However, studies on the number of stents for optimal drainage of PFCs are limited. Hence, the present study was conducted to compare the outcome of single versus two double-pigtail stents for endoscopic drainage of PFCs. Methods This is a single-center, retrospective analysis of patients undergoing endoscopic drainage of PFCs with minimal necrosis (pseudocyst or walled-off necrosis with <30% solid content) at a tertiary center in South India from October 2020 to October 2022. Post-procedure, patients were followed up for clinical improvement, and stents were removed after documentation of cyst size reduction on imaging. Results Sixty-three patients (82.5% males, median age: 34 years) fulfilling the selection criteria were included. For single stent placement (n = 47), stents of size 8.5 Fr or 10 Fr were used, while for placement of two stents (n = 16), 7 Fr stents were used. The technical success rate was 100%. Intraprocedural and early postprocedural adverse events (all mild to moderate) were comparable between the groups (17.0% with single stent vs. 25.0% with two stents, p = NS). Clinical success was achieved in 93.6% of patients, with no difference between both groups. Three patients in the single stent group required additional procedures. All patients underwent successful stent removal after a median follow-up of 14 weeks. Conclusion A single pigtail stent of 8.5 Fr or 10 Fr size for EUSguided cystogastrostomy provides efficacy and safety similar to that of two stents.
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Reply: Portal vein thrombosis in cirrhosis: exploring the uncharted waters. J Gastroenterol Hepatol 2023; 38:2254. [PMID: 37804045 DOI: 10.1111/jgh.16378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 09/25/2023] [Indexed: 10/08/2023]
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Insights into the catalytic activity of boron-doped thiazoles in the Diels-Alder reaction. Phys Chem Chem Phys 2023; 25:23708-23716. [PMID: 37614158 DOI: 10.1039/d3cp02441e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Abstract
The role of boron-doped thiazoles as a Lewis acid catalyst in [4+2] cycloaddition reaction between 1,3-butadiene and acrolein has been addressed. Three different organic heterocycles were designed to study their catalytic activity. It has been observed that these heterocycles efficiently work as catalysts than the well-known Lewis acid BF3. All the reactions follow the normal electron demand process and are exothermic. Different conceptual DFT-based reactivity descriptors and electronic structure principles such as maximum hardness and minimum electrophilicity lend additional support to the feasibility of the reaction mechanism. The reaction force (RF), reaction electronic flux (REF), and its different components exhibit a detailed electronic activity throughout the reaction.
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Concept-Driven Chemoselective O/N-Derivatization of Prolinol: A Bee-Line Approach to Access Organocatalysts. J Org Chem 2023. [PMID: 37402179 DOI: 10.1021/acs.joc.3c00992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/06/2023]
Abstract
An investigation into the sensitivity of reaction conditions to a highly utilized protocol has been reported, wherein the mono-Boc functionalization of prolinol could be controlled for the exclusive synthesis of either N-Boc, O-Boc, or oxazolidinone derivatives. Mechanistic investigation revealed that the elementary steps could possibly be controlled by (a) a requisite base to recognize the differently acidic sites (NH and OH) for the formation of the conjugate base, which reacts with the electrophile, and (b) the difference in nucleophilicity of the conjugate basic sites. Herein, a successful chemoselective functionalization of the nucleophilic sites of prolinol by employing a suitable base is reported. This has been achieved by exploiting the relative acidity difference of NH and OH along with the reversed nucleophilicity of the corresponding conjugate bases N- and O-. This protocol has also been used for the synthesis of several O-functionalized prolinol derived organocatalysts, few of which have been newly reported.
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Does the wire diameter really determine the outcomes in cold snare polypectomy? J Gastroenterol Hepatol 2023; 38:665. [PMID: 36866450 DOI: 10.1111/jgh.16160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Accepted: 02/27/2023] [Indexed: 03/04/2023]
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Exploring an intermolecular Ge/B frustrated Lewis pair from a multicentre Zintl Lewis base. Theor Chem Acc 2023. [DOI: 10.1007/s00214-023-02961-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Impact of baseline frailty on Early Mortality among older adults with Gastrointestinal Malignancies: A nested Case Control Study. J Geriatr Oncol 2022. [DOI: 10.1016/s1879-4068(22)00409-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Implementation of the Web-Enabled Cancer & Aging Resilience Evaluation (WeCARE) in an Outpatient Oncology Setting. J Geriatr Oncol 2022. [DOI: 10.1016/s1879-4068(22)00351-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Functionalized nona-silicide [Si 9R 3] Zintl clusters: a new class of superhalogens. Phys Chem Chem Phys 2022; 24:21105-21111. [PMID: 36018293 DOI: 10.1039/d2cp02619h] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Superatoms, due to their various applications in redox and materials chemistry, have been a major topic of study in cluster science. Superhalogens constitute a special class of superatoms that mimic the chemistry of halogens and serve as building blocks of novel materials such as super and hyper salts, perovskite-based solar cells, solid-state electrolytes, and ferroelectric materials. These applications have led to a constant search for new class of superhalogens. In this study, using density functional theory, we show that recently synthesized [Si9{Si (tBu)2H}3] and [Si9{Si (TMS)3}3] Zintl clusters not only behave like halogens but also when functionalized with suitable ligands exhibit superhalogen characteristics. Frontier molecular orbital (FMO) analyses give insights into the electron-accepting nature of the Zintl clusters. Additional bonding techniques such as energy density at the bond critical point (BCP) and adaptive natural density partitioning (AdNDP) gives complementary information about the nature of bonding in Si9-based Zintl clusters. The potential of these Zintl clusters in the synthesis of new electrolytes in Li-ion batteries is also investigated.
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Dioxidomolybdenum(VI) complexes of azo-hydrazones: Structural investigation, DNA binding and cytotoxicity studies. Polyhedron 2022. [DOI: 10.1016/j.poly.2022.116093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Coexisting ferromagnetic component and negative magnetoresistance at low temperature in single crystals of the VdW material GaGeTe. J SOLID STATE CHEM 2022. [DOI: 10.1016/j.jssc.2022.123106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Stopping rules for 5-ASA in UC need to be redefined. J Gastroenterol Hepatol 2022; 37:1404. [PMID: 35514184 DOI: 10.1111/jgh.15884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 05/02/2022] [Indexed: 12/09/2022]
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GGT dynamic for advanced fibrosis in NAFLD: Novel but not convincing. J Gastroenterol Hepatol 2022; 37:1406. [PMID: 35639554 DOI: 10.1111/jgh.15908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Revised: 05/19/2022] [Accepted: 05/29/2022] [Indexed: 12/09/2022]
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CHESS-ALARM Score: Can it raise the ALARM accurately? J Gastroenterol Hepatol 2022; 37:955. [PMID: 35352409 DOI: 10.1111/jgh.15840] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 03/28/2022] [Indexed: 12/09/2022]
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Improving the outcome of gastrointestinal bleeding in ESRD patients: The need of the hour. J Gastroenterol Hepatol 2022; 37:773. [PMID: 35132698 DOI: 10.1111/jgh.15794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 01/30/2022] [Indexed: 12/09/2022]
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Triazole-linked pyrene appended xylofuranose derivatives for selective detection of Au3+ ions in aqueous medium and DFT calculations. J Photochem Photobiol A Chem 2022. [DOI: 10.1016/j.jphotochem.2021.113723] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Structural correlation to ferroelectric order, non-Griffiths like phase and magnetocaloric effect in YbCrO 4. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:155402. [PMID: 35073536 DOI: 10.1088/1361-648x/ac4e46] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 01/24/2022] [Indexed: 06/14/2023]
Abstract
We report a ferroelectric order around ∼99 K (TFE), which is considerably above the long range ferrimagnetic order at 25 K (TN). The value of saturation electric polarization is considerable as ∼570μC m-2for a poling field of 5 kV cm-1. The ferroelectric order is associated with a significant magnetoelectric coupling below ∼90 K. A weak signature ofTFEis observed in the dielectric constant, which is associated with a linear magnetodielectric response at 18 K(<TN). A transition to a polar structure has been correlated with the occurrence of ferroelectric order. A non-Griffiths like phase is observed around ∼48 K, which is also linked with the structural distortion. A reasonable value of the magnetic entropy change of 5.07 J Kg-1 K-1is noted atTNfor a change in field of 50 kOe, which involves a strong magnetoelastic coupling. The results indicate considerable structural instabilities, which is linked with the observed multifunctional properties of YbCrO4.
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Ligand effect on the stability, reactivity, and acidity of imidazolium systems. J PHYS ORG CHEM 2022. [DOI: 10.1002/poc.4331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Increasing the recommended colon withdrawal time to improve colonoscopy quality: Is it high time? J Gastroenterol Hepatol 2022; 37:406. [PMID: 34859502 DOI: 10.1111/jgh.15747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Accepted: 11/18/2021] [Indexed: 12/09/2022]
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Pyridine and pyrimidine functionalized half-sandwich Ru(II)-N heterocyclic carbene complexes: Synthesis, structures, spectra, electrochemistry and biological studies. J Mol Struct 2021. [DOI: 10.1016/j.molstruc.2021.130939] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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23
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The impact of sarcopenia on survival among adults with hematologic malignancies: A systematic review and meta-analysis. J Geriatr Oncol 2021. [DOI: 10.1016/s1879-4068(21)00359-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Discordance between simplified Frailty Score and the IMWG frailty score among newly diagnosed older adults with Multiple Myeloma: Findings from the CARE-HEME registry. J Geriatr Oncol 2021. [DOI: 10.1016/s1879-4068(21)00453-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Effect of confinement on the behavior of superhalogen and superalkali. COMPUT THEOR CHEM 2021. [DOI: 10.1016/j.comptc.2021.113491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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180 NURSING HOMES DURING THE COVID-19 PANDEMIC: A NARRATIVE REVIEW OF CHALLENGES AND RESPONSES. Age Ageing 2021. [PMCID: PMC8690028 DOI: 10.1093/ageing/afab219.180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Background COVID-19 has caused unprecedented challenges in nursing homes. In this narrative review, we aimed to describe factors that contributed to the spread and mortality of COVID-19 in nursing homes and provide an overview of responses that were implemented to try to overcome such challenges. Methods The MeSH terms ‘Nursing homes’ and ‘COVID-19’ were searched in MEDLINE Ovid, and English language articles were retrieved that were published between 1 March 2020 and 31 January 2021. Article titles and abstracts were screened by two reviewers, and the results of included articles were grouped by themes. Results The search retrieved 348 articles, of which 76 were included in the thematic review. 8 articles related to COVID-19 disease characteristics (e.g. asymptomatic transmission), 24 to resident-related factors (e.g. comorbidities, nutrition, cognition), 13 to facility characteristics (e.g. physical space, occupancy, for-profit status), 21 to staffing (e.g. staffing levels, staff-to-resident ratio, staff multi-employment), and 10 to external factors (e.g. availability of personal protective equipment, prevailing health and social care policies). In terms of responses, identified themes included widespread testing, isolation and cohorting of residents, staff protection and support, promotion of residents’ well-being, and technological innovations. Conclusion COVID-19 exerted severe challenges on the nursing home population and its staff. Both internal and external factors predisposed nursing homes to an increased propensity of spread. Numerous strategies were employed to attempt to mitigate the negative impacts. Substantial learning occurred that may not only aid future pandemic preparedness but improve quality of care for nursing home residents at all times.
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Use of personal protective equipment among waste workers of Sisdol landfill site of Nepal. INTERNATIONAL JOURNAL OF OCCUPATIONAL SAFETY AND HEALTH 2021. [DOI: 10.3126/ijosh.v11i3.39768] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Introduction: Solid waste management is a major issue in Nepal with Kathmandu valley generating the highest amount of solid waste. After recovery, the solid waste generated in Kathmandu valley is transferred to the Sisdol landfill site. There are waste workers in Sisdol landfill site who sustain their livelihood by collecting recyclables from those wastes. Personal protective equipment (PPE) is necessary to protect the frontline waste workers against infection. In addition, the waste workers need to know the proper usage of PPE in order to protect themselves from contamination. This study aimed to assess the awareness and proper usage of PPE along with the challenges faced by the waste workers at Sisdol landfill site.
Methods: A descriptive cross-sectional study was conducted to collect data from landfill waste workers of Sisdol located at Kakani Rural Municipality in Nuwakot district of Nepal. A convenience sampling method was used based on the availability of landfill waste workers on that day and their willingness to participate. The data was collected using the structured questionnaire and personal interview of available waste workers.
Results: The study comprised of 65% female and 35% male waste workers. The highest percentage of waste workers belong to 27-37 age group occupying 43% of total respondents. Around 92% waste workers had participated in any orientation/training or session related to PPE and its usage. About 60% landfill waste workers were found only using mask and gloves.
Conclusion: There is small number of waste workers who wish to wear full set of PPE. Most of them only like to wear mask and gloves. The gender, age group and the education level of waste workers had no association with the usage of PPE during the work.
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Incidence of iatrogenic urethral catheterisation injuries: A prospective multicentre audit. EUR UROL SUPPL 2021. [DOI: 10.1016/s2666-1683(21)00196-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Abstract
Superalkalis and superhalogens are atomic clusters that mimic the chemistry of alkali and halogen atoms, respectively; the ionization energies of the superalkalis are less than those of alkali atoms, while the electron affinities of superhalogens are larger than those of the halogen atoms. These superions can serve as the building blocks of a new class of supersalts with applications in solar cells, metal-ion batteries, multiferroic materials, and so on. While considerable progress has been made in the design and synthesis of superhalogens, a similar understanding of superalkalis is lacking. Using density functional theory with hybrid exchange-correlation functional and Gaussian basis sets, we have systematically studied the role of size and composition on the properties of two different classes of clusters whose stabilities are governed by the Wade-Mingos polyhedral skeletal electron pair theory. One class belongs to the closo-borane family LimBnXn (m = 1, 2, 3; n = 6, 12; X = H, F, CN), while the other to the Zintl ions Lim[Be@Ge9]. We show that Li3BnXn and Li3[Be@Ge9] clusters are superalkalis with ionization energies as low as 2.84 eV in Li3B6H6. However, contrary to expectation, the ionization energies do not decrease with increasing cluster volume. Instead, ionization energies are linked to the X ligands' electron affinities; the larger the electron affinity, the higher is the ionization energy. The understanding gained here will help in the discovery of superalkalis and, hence, enrich the library of supersalts.
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Pyridine and pyrimidine functionalized half-sandwich Ru(II)-N heterocyclic carbene complexes: Synthesis, structures, spectra, electrochemistry and biological studies. J Mol Struct 2021. [DOI: 10.1016/j.molstruc.2020.129822] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Significant magneto-elastic coupling at Griffiths-like phase boundaries in low dimensional oxides, ASb 2O 6( A=Ni and Mn). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:195701. [PMID: 33542167 DOI: 10.1088/1361-648x/abe350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 02/04/2021] [Indexed: 06/12/2023]
Abstract
The compounds, NiSb2O6(NSO) and MnSb2O6(MSO) attract the community for the quasi one-dimensional and layered structure composed of Ni2+and Mn2+, which orders antiferromagnetically atTN= 6.7 and 12 K, respectively. Here, we report the Griffiths-like phase much aboveTNin the range of 37-85 K and 25-80 K for NSO and MSO, respectively. The dc magnetization results indicate the Griffiths-like phase, following the modified Curie-Weiss law. The magneto-capacitive responses for both the compounds show anomalies at the onset of the Griffiths-like phase. Intriguingly, the low temperature synchrotron diffraction results are conclusive for determining the singularities for both the compounds. Interplay between the low-dimensionality, magnetic frustration, and magneto-elastic coupling correlates the observed short range ordered state, which is suggested as a Griffiths-like phase, aboveTNfor both the compounds.
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Abstract
In quest of a Zintl ion-based Lewis superacids, Al(Ge9L3)3 {L= H, CH3, CHO and CN} compounds have been designed and their properties have been studied within the framework of conceptual density functional theory-based reactivity descriptors. Superacid property has been identified for these complexes as per the fluoride ion affinity (FIA) values. Studies reveal that Al[Ge9(CN)3]3 and Al[Ge9(CH3)3]3 behave like superacids as their FIA exceeds the value of SbF5, which is considered as the strongest Lewis acid. It has been observed that the ligand plays an important role in reactivity as well as in Lewis acidic property.
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Active Bromoaniline-Aldehyde Conjugate Systems and Their Complexes as Versatile Sensors of Multiple Cations with Logic Formulation and Efficient DNA/HSA-Binding Efficacy: Combined Experimental and Theoretical Approach. ACS OMEGA 2021; 6:3659-3674. [PMID: 33585746 PMCID: PMC7876678 DOI: 10.1021/acsomega.0c05189] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Accepted: 01/11/2021] [Indexed: 05/12/2023]
Abstract
Two fluorescence active bromoaniline-based Schiff base chemosensors, namely, (E)-4-bromo-2-(((4-bromophenyl)imino)methyl)phenol (HL1 ) and (E)-2-(((4-bromophenyl)imino)methyl)phenol (HL2 ), have been employed for the selective and notable detection of Cu2+ and Zn2+ ions, respectively, with the simultaneous formation of two new metal complexes [Cu(L1)2] (1) and [Zn(L2)2] (2). X-ray single crystal analyses indicate that complexes 1 and 2 are tetra-coordinated systems with substantial CH...π/π...π stacking interactions in the solid-state crystal structures. These two complexes are exploited for the next step detection of Al3+ and Hg2+ where complex 2 exhibits impressive results via turn-off fluorescence quenching in (DMSO/H2O) HEPES buffer medium. The sensing phenomena are optimized by UV-vis spectral analyses as well as theoretical calculations (density functional theory and time-dependent density functional theory). The combined detection phenomena of the ligand (HL2 ) and complex 2 are exclusively utilized for the first time to construct a molecular memory device, intensifying their multisensoric properties. Furthermore, the DNA- and human serum albumin (HSA)-binding efficacies of these two complexes are examined by adopting electronic and fluorometric titration methods. Complex 2 shows a higher DNA-binding ability in comparison with complex 1, whereas in the case of HSA, the reverse situation is observed. Finally, the binding modes of both the complexes with DNA and HSA have been investigated through molecular docking studies, suggesting good agreement with the experimental results.
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Unraveling the origin of interactions of hydroxychloroquine with the receptor-binding domain of SARS-CoV-2 in aqueous medium. Chem Phys Lett 2021; 764:138280. [PMID: 33362291 PMCID: PMC7748971 DOI: 10.1016/j.cplett.2020.138280] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 12/13/2020] [Accepted: 12/14/2020] [Indexed: 12/23/2022]
Abstract
Interactions of hydroxychloroquin (HCQ) with the receptor binding domain (RBD) of SARS-CoV-2 were studied from atomistic simulation and ONIOM techniques. The key-residues of RBD responsible for the human transmission are recognized to be blocked in a heterogeneous manner with the favorable formation of key-residue:HCQ (1:1) complex. Such heterogeneity in binding was identified to be governed by the differential life-time of the hydrogen bonded water network anchoring HCQ and the key-residues. The intermolecular proton transfer facilitates the most favorable Lys417:HCQ complexation. The study demonstrates that off-target bindings of HCQ need to be minimized to efficiently prevent the transmission of SARS-CoV-2.
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Circulation of GII.4 norovirus strains in children <5 years hospitalized at a tertiary care teaching hospital in south India: 2005–2018. Int J Infect Dis 2020. [DOI: 10.1016/j.ijid.2020.09.1305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Enteric virus detection from acute gastroenteritis cases in a tertiary care hospital before and after rotavirus vaccine introduction, India: 2012–2019. Int J Infect Dis 2020. [DOI: 10.1016/j.ijid.2020.09.1316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Stool shedding of Salmonella Typhi in children with blood culture-confirmed typhoid fever. Int J Infect Dis 2020. [DOI: 10.1016/j.ijid.2020.09.337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Norovirus and rotavirus gastroenteritis in children <5 years in the inpatient and outpatient settings of a tertiary care hospital in south India. Int J Infect Dis 2020. [DOI: 10.1016/j.ijid.2020.09.1354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Correction to Oxidation-Induced Differentially Selective Turn-On Fluorescence via Photoinduced Electron Transfer Based on a Ferrocene-Appended Coumarin–Quinoline Platform: Application in Cascaded Molecular Logic. Inorg Chem 2020; 59:16091-16094. [DOI: 10.1021/acs.inorgchem.0c02921] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Omega-3 lipid metabolites as mediators of metformin’s anti-proliferative effect in ovarian cancer. Gynecol Oncol 2020. [DOI: 10.1016/j.ygyno.2020.05.148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Calorie restriction for ovarian cancer reduction. Gynecol Oncol 2020. [DOI: 10.1016/j.ygyno.2020.05.137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Density Functional Treatment on Alkylation of a Functionalized Deltahedral Zintl Cluster. J Phys Chem A 2020; 124:7248-7258. [PMID: 32786962 DOI: 10.1021/acs.jpca.0c03254] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Density functional theory (DFT) is one of the popular methods to understand the electronic structure of molecular systems based on electronic density. On the basis of this theory, several conceptual DFT descriptors have been developed which can deal with the stability, reactivity, and several other physicochemical properties of molecules. Here, we have taken a nine-atom-functionalized deltahedral Zintl cluster of germanium (Ge) to examine the alkylation reaction mechanism. The study showed that the Zintl cluster having a methyl group as a ligand, [Ge9(CH3)3-], acts as a better nucleophile than the cyanide (-CN)-substituted cluster [Ge9(CN)3-] in terms of different thermodynamic parameters like free energy, enthalpy of activation, reaction energy, etc. A detailed reaction electronic flux analysis reveals the nature of the electronic activity throughout the reaction pathway. The reaction force, Wiberg bond indices, and dual descriptor lend additional support to the reaction mechanism. It has been found that the alkylation reaction between the Zintl ion and the alkyl halide follows a SN2-like mechanism.
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Interplay between positive magnetoresistance and thermoelectric properties by tuning carrier concentration in Sb 2-xSn xTe 3( x⩽ 0.05) crystals. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:435601. [PMID: 32634794 DOI: 10.1088/1361-648x/aba386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 07/07/2020] [Indexed: 06/11/2023]
Abstract
We report transport properties of Sb2-xSnxTe3(x⩽ 0.05) single crystals, where the tuning of the charge carrier densities via Sn doping significantly improves the magnetoresistance (MR) and the thermoelectric (TE) properties. The MR increases significantly at 2 K forx= 0.01, which reduces considerably with further Sn doping atx= 0.05. The MR results below 90 K forx= 0.01 satisfy the semi-classical two-band approach of Kohler's rule, which does not satisfy the MR results forx= 0.05. At 300 K, the Seebeck coefficient (S) is positive and small forx= 0.01 and it changes the sign with the further increase in Sn doping atx= 0.05 at 300 K. The value of |S| is considerable with an enhancement of the thermoelectric power factor compared to the value forx= 0.01 at 300 K. Analysis of the Hall conductivity indicates the interplay between carrier mobilities and densities, leading to the tuning of MR and TE properties with Sn doping. These results demonstrate that the p-type Sb2Te3becomes n-type with a suitable doping engineering.
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Cycloaddition Reactions between H2C = CHR (R = H, CN, CH3) and a Cyclic P/B Frustrated Lewis Pair: A DFT Study. J Phys Chem A 2020; 124:4455-4462. [DOI: 10.1021/acs.jpca.0c02799] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Single pot reaction of Co(III) and Ni(II) hydrogen-bonded organic frameworks and multidisciplinary application in dye adsorption, separation and DNA binding. J Mol Struct 2020. [DOI: 10.1016/j.molstruc.2020.127727] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Oxidation-Induced Differentially Selective Turn-On Fluorescence via Photoinduced Electron Transfer Based on a Ferrocene-Appended Coumarin-Quinoline Platform: Application in Cascaded Molecular Logic. Inorg Chem 2020; 59:4493-4507. [PMID: 32159340 DOI: 10.1021/acs.inorgchem.9b03650] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Differentially selective molecular sensors that exhibit differential response toward multiple analytes are cost-effective and in high demand for various practical applications. A novel, highly differentially selective electrochemical and fluorescent chemosensor, 5, based on a ferrocene-appended coumarin-quinoline platform has been designed and synthesized. Our designed probe is very specific toward Fe3+ via a reversible redox process, whereas it detects Cu2+ via irreversible oxidation. Interestingly, it exhibits differential affinity toward the Cu+ ion via complexation. High-resolution mass spectrometry, 1H NMR titration, and IR spectral studies revealed the formation of a bidentate Cu+ complex involving an O atom of the amide group attached to the quinoline ring and a N atom of imine unit, and this observation was further supported by quantum-chemical calculations. The metal binding responses were further investigated by UV-vis, fluorescence spectroscopy, and electrochemical analysis. Upon the addition of Fe3+ and Cu2+ ions, the fluorescence emission of probe 5 shows a "turn-on" signal due to inhibition of the photoinduced electron transfer (PET) process from a donor ferrocene unit to an excited-state fluorophore. The addition of sodium l-ascorbate (LAS) as a reducing agent causes fluorescence "turn off" for the Fe3+ ion because of reemergence of the PET process but not for the Cu2+ ion because it oxidizes the ferrocene unit to a ferrocenium ion with its concomitant reduction to Cu+, which further complexes with 5. Thermodynamic calculations using the Weller equation along with density functional theory calculations validate the feasibility of the PET process. A unique combination of Fe3+, LAS, and Cu2+ ions has been used to produce a molecular system demonstrating combinational "AND-OR" logic operation.
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