Nitrene Transfer Reactions Mediated by Transition Metal Scorpionate Complexes
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Heavier Group 2 Metal Complexes with a Flexible Scorpionate
RSC Advances View Article Online PAPER View Journal | View Issue Heavier group 2 metal complexes with a flexible scorpionate ligand based on 2-mercaptopyridine† Cite this: RSC Adv.,2015,5,51413 Kishor Naktode,a Th. Dhileep N. Reddy,a Hari Pada Nayek,b Bhabani S. Mallik*a and Tarun K. Panda*a 2 We report the synthesis of novel alkaline earth metal complexes [k -SS-(Bmp)2M(THF)n][M¼ Ca (2), Sr (3) n ¼ 2; M ¼ Ba (4), n ¼ 3] of a flexible dihydrobis(2-thiopyridone)borate (Bmp) ligand based on 2- mercaptopyridine. Complexes 2–4 were isolated in good yield by the reaction between sodium dihydrobis(2-thiopyridone)borate, [{(Bmp)Na(THF)}2]n (1) and the corresponding alkaline earth metal diiodides in toluene at ambient temperature. The solid-state structures of the strontium and barium complexes, complexes 3 and 4 respectively, were established using single-crystal X-ray diffraction analysis. The solid-state structure of sodium complex 1 was also confirmed using X-ray techniques. The solid-state structures of complexes 3 and 4 revealed that the Bmp ligand coordinates through sulphur atoms to the metal ions in k2 fashion. The strontium ion is attached symmetrically and the barium ion is Creative Commons Attribution 3.0 Unported Licence. asymmetrically linked with the Bmp ligand, manifesting the 2-thiopyridone and pyridine-2-thiolate tautomeric form of the Bmp ligand. The strontium ion in complex 3 adopts a distorted octahedral geometry whereas the geometry around the barium ion can best be described as a distorted pentagonal Received 17th March 2015 bipyramidal. -
Complexes Of
www.nature.com/scientificreports OPEN Heteroleptic Copper(I) Complexes of “Scorpionate” Bis-pyrazolyl Carboxylate Ligand with Auxiliary Received: 13 December 2016 Accepted: 21 February 2017 Phosphine as Potential Anticancer Published: 24 March 2017 Agents: An Insight into Cytotoxic Mode Rais Ahmad Khan1, Mohammad Usman2, Rajakumar Dhivya3, Perumalsamy Balaji3, Ali Alsalme1, Hamad AlLohedan1,4, Farukh Arjmand2, Khalid AlFarhan1, Mohammad Abdulkader Akbarsha3, Fabio Marchetti5, Claudio Pettinari5 & Sartaj Tabassum1,2,4 New copper(I) complexes [CuCl(PPh3)(L)] (1: L = LA = 4-carboxyphenyl)bis(3,5-dimethylpyrazolyl) methane; (2: L = LB = 3-carboxyphenyl)bis(3,5-dimethylpyrazolyl)methane) were prepared and characterised by elemental analysis and various spectroscopic techniques such as FT-IR, NMR, UV–Vis, and ESI-MS. The molecular structures of complexes 1 and 2 were analyzed by theoretical B3LYP/DFT method. Furthermore, in vitro DNA binding studies were carried out to check the ability of complexes 1 and 2 to interact with native calf thymus DNA (CT-DNA) using absorption titration, fluorescence quenching and circular dichroism, which is indicative of more avid binding of the complex 1. Moreover, DNA mobility assay was also conducted to study the concentration-dependent cleavage pattern of pBR322 DNA by complex 1, and the role of ROS species to have a mechanistic insight on the cleavage pattern, which ascertained substantial roles by both hydrolytic and oxidative pathways. Additionally, we analyzed the potential of the interaction of complex 1 with DNA and enzyme (Topo I and II) with the aid of molecular modeling. Furthermore, cytotoxic activity of complex 1 was tested against HepG2 cancer cell lines. -
Reversible Metalation and Catalysis with a Scorpionate-Like Metallo- Ligand in a Metal−Organic Framework Chenyue Sun, Grigorii Skorupskii, Jin-Hu Dou, Ashley M
Communication Cite This: J. Am. Chem. Soc. 2018, 140, 17394−17398 pubs.acs.org/JACS Reversible Metalation and Catalysis with a Scorpionate-like Metallo- ligand in a Metal−Organic Framework Chenyue Sun, Grigorii Skorupskii, Jin-Hu Dou, Ashley M. Wright, and Mircea Dinca*̆ Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States *S Supporting Information these supports makes any attempts to understand and control − ABSTRACT: The installation of metallo-ligands in the active site difficult.12 16 metal−organic frameworks (MOFs) is an effective One class of hybrid solids that provide exceptional structural means to create site-isolated metal centers toward uniformity are metal−organic frameworks (MOFs).17 These single-site heterogeneous catalysis. Although trispyrazoly- materials’ ability to preserve a molecule-like coordination borate (Tp) and tripyrazolylmethane (Tpm) form one of environment in a rigid and well-defined solid is highlighted by the most iconic classes of homogeneous catalysts, neither their utility as single-site heterogeneous catalysts18,19 and as has been used as a metallo-ligand for the generation of catalyst promoters.20 The anionic Tp itself is mimicked by the MOFs thus far. Here, we show that upon in situ coordination environment of secondary building units (SBUs) I metalation with Cu , a tricarboxylated Tpm ligand reacts of a series of azolate-based MOFs.21,22 Metal substitution at 23,24 with ZrOCl2 to generate a new MOF exhibiting neutral these SBUs provided heterogeneous catalysts for a range of scorpionate-like chelating sites. These sites undergo for processes including ethylene oligomerization, polymerization, − facile demetalation and remetalation with retention of and C−H amination.25 27 It is harder, however, to devise or I crystallinity and porosity. -
New Methods for the Synthesis of Heterocyclic Compounds*
Pure Appl. Chem., Vol. 76, No. 3, pp. 603–613, 2004. © 2004 IUPAC New methods for the synthesis of heterocyclic compounds* Aldo Caiazzo1, Shadi Dalili1, Christine Picard2, Mikio Sasaki1, Tung Siu2, and Andrei K. Yudin1,‡ 1Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada; 2Ylektra, Inc., 100 University Ave., 10th Floor, South Tower, Toronto, Ontario M5J 1V6, Canada Abstract: Due to frequent occurrence of nitrogen-containing groups among the biologically active compounds, chemoselective functionalization of organic molecules with nitrogen-con- taining functional groups is an important area of organic synthesis. We have proposed and implemented a new strategy toward design of nitrogen-transfer reactions on inert electrode surfaces with a particular focus on the generation and trapping of highly reactive nitrogen- transfer agents. A wide range of structurally dissimilar olefins can be readily transformed into the corresponding aziridines. The resulting aziridines are precursors to a range of cata- lysts via nucleophilic ring-opening with diaryl- and dialkyl phosphines. Another strategy ex- plored in the context of oxidative nitrogen transfer is cycloamination of olefins using NH aziridines. INTRODUCTION The transformations of organic compounds belong to one of the following two broad categories: car- bon–carbon bond-forming reactions and redox processes. Over the years, remarkable progress has been achieved in design and applications of novel metal-based complexes in oxidation chemistry. The metal center of such a catalyst is surrounded by a ligand, which resembles and emulates the function of the enzyme active site. This strategy is known to adequately address the issues of regio-, chemo-, and stereoselectivity in a number of synthetic transformations. -
Recent Advances in Titanium Radical Redox Catalysis
JOCSynopsis Cite This: J. Org. Chem. 2019, 84, 14369−14380 pubs.acs.org/joc Recent Advances in Titanium Radical Redox Catalysis Terry McCallum, Xiangyu Wu, and Song Lin* Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States ABSTRACT: New catalytic strategies that leverage single-electron redox events have provided chemists with useful tools for solving synthetic problems. In this context, Ti offers opportunities that are complementary to late transition metals for reaction discovery. Following foundational work on epoxide reductive functionalization, recent methodological advances have significantly expanded the repertoire of Ti radical chemistry. This Synopsis summarizes recent developments in the burgeoning area of Ti radical catalysis with a focus on innovative catalytic strategies such as radical redox-relay and dual catalysis. 1. INTRODUCTION a green chemistry perspective, the abundance and low toxicity of Ti make its complexes highly attractive as reagents and Radical-based chemistry has long been a cornerstone of 5 1 catalysts in organic synthesis. synthetic organic chemistry. The high reactivity of organic IV/III radicals has made possible myriad new reactions that cannot be A classic example of Ti -mediated reactivity is the reductive ring opening of epoxides. This process preferentially readily achieved using two-electron chemistry. However, the − high reactivity of organic radicals is a double-edged sword, as cleaves and functionalizes the more substituted C O bond, the selectivity of these fleeting intermediates can be difficult to providing complementary regioselectivity to Lewis acid control in the presence of multiple chemotypes. In addition, promoted epoxide reactions. The synthetic value of Ti redox catalysis has been highlighted by their many uses in total catalyst-controlled regio- and stereoselective reactions involv- 6−10 ing free-radical intermediates remain limited,2 and the synthesis (Scheme 1). -
The Synthesis and Applications of N-Alkenyl Aziridines
The Synthesis and Applications of N-Alkenyl Aziridines by Nicholas A. Afagh A thesis submitted in conformity with the requirements for the degree of Master of Science Department of Chemistry University of Toronto © Copyright by Nicholas A. Afagh 2010 The Synthesis and Applications of N-Alkenyl Aziridines Nicholas A. Afagh Master of Science Department of Chemistry University of Toronto 2010 Abstract N-alkenyl aziridines are a unique class of molecules that do not behave as typical enamines as a result of the inability of the nitrogen atom lone-pair of electrons to delocalize. The attenuated nucleophilicity of these enamines presents opportunities for the selective functionalization and reactivity not available to classical enamines. An operationally simple and mild copper-mediated coupling has been developed that facilitates the preparation of a broad range of N-alkenyl aziridines not available through existing methods. The preparation and reactivity of highly- functionalized N-alkenyl aziridines are reported. Also reported is the application of the chemoselective amine/aldehyde/alkyne (A 3) multicomponent coupling involving amphoteric aziridine aldehydes as the aldehyde component. This coupling allows access to propargyl amines with pendent aziridine functionality. ii Acknowledgments First and foremost, I would like to thank my supervisor, Professor Andrei K. Yudin for his continuous support and encouragement over the past two years. His wealth of knowledge and profound insight into all matters chemistry made for many interesting discussions. In addition, I would like to thank all the members of the Yudin group past and present with whom I have had the distinct pleasure of working alongside and shared many late evenings. -
Carbene and Nitrene Transfer Reactions Joseph B
University of South Florida Scholar Commons Graduate Theses and Dissertations Graduate School 11-19-2014 Co(II) Based Metalloradical Catalysis: Carbene and Nitrene Transfer Reactions Joseph B. Gill University of South Florida, [email protected] Follow this and additional works at: https://scholarcommons.usf.edu/etd Part of the Organic Chemistry Commons Scholar Commons Citation Gill, Joseph B., "Co(II) Based Metalloradical Catalysis: Carbene and Nitrene Transfer Reactions" (2014). Graduate Theses and Dissertations. https://scholarcommons.usf.edu/etd/5484 This Dissertation is brought to you for free and open access by the Graduate School at Scholar Commons. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Scholar Commons. For more information, please contact [email protected]. Co(II) Based Metalloradical Catalysis: Carbene and Nitrene Transfer Reactions by Joseph B. Gill A dissertation in partial fulfillment of the requirements for the degree of Doctor of Philosophy Department of Chemistry College of Arts and Sciences University of South Florida Major Professor: X. Peter Zhang, Ph.D. Jon Antilla, Ph.D Jianfeng Cai, Ph.D. Edward Turos, Ph.D. Date of Approval: November 19, 2014 Keywords: cyclopropanation, diazoacetate, azide, porphyrin, cobalt. Copyright © 2014, Joseph B. Gill Dedication I dedicate this work to my parents: Larry and Karen, siblings: Jason and Jessica, and my partner: Darnell, for their constant support. Without all of you I would never have made it through this journey. Thank you. Acknowledgments I would like to thank my advisor, Professor X. Peter Zhang, for his support and guidance throughout my time working with him. -
Aziridination of Alkenes Promoted by Iron Or Ruthenium Complexes
Aziridination of Alkenes Promoted by Iron or Ruthenium Complexes Caterina Damiano, Daniela Intrieri and Emma Gallo* Department of Chemistry, University of Milan, Via C. Golgi 19, 20133 Milan (Italy). E-mail address: [email protected]. Keywords: Aziridines, Nitrene reagents, Alkenes, Homogenous catalysis, Iron, Ruthenium. Abstract Molecules containing an aziridine functional group are a versatile class of organic synthons due to the presence of a strained three member, which can be easily involved in ring-opening reactions and the aziridine functionality often show interesting pharmaceutical and/or biological behaviours. For these reasons, the scientific community is constantly interested in developing efficient procedures to introduce an aziridine moiety into organic skeletons and the one-pot reaction of an alkene double bond with a nitrene [NR] source is a powerful synthetic strategy. Herein we describe the catalytic activity of iron or ruthenium complexes in promoting the reaction stated above by stressing the potential and limits of each synthetic protocol. 1. Introduction Aziridines, the smallest N-heterocycle compounds, have attracted considerable attention in the last few decades due to their many applications in biological and synthetic chemistry [1]. The aziridine functionality is often responsible for the activity of biologically active species (such as antitumor compounds, antibiotics and enzyme inhibitors) and aziridine containing molecules [2] are also useful building blocks in the synthesis of fine chemicals and pharmaceuticals [3-6]. The striking chemical properties of aziridines are due to the energy associated to the strained three- membered ring [7], which renders them very active and versatile starting materials for the synthesis of several useful molecules such as amines, amino acids, β-lactams, polymers and α-amido ketones [8, 9]. -
Steven Kealey
Synthesis and Coordination Chemistry of Scorpionate Ligands and their Applications in 11C—Positron Emission Tomography Steven Kealey Submitted in Partial Fulfilment of the Requirements for the Degree of Doctor of Philosophy Supervisor: Prof. N. J. Long Department of Chemistry Imperial College London April 2008 STATEMENT OF COPYRIGHT The copyright of this thesis rests with the author. No quotation from it should be published without the prior written consent of the author and information derived from it should be acknowledged appropriately. DECLARATION The work described in this thesis was carried out in the Department of Chemistry, Imperial College London, between October 2004 and December 2007. The entire body of work is my own unless otherwise stated to the contrary and has not been submitted previously for a degree at this or any other university. i ABSTRACT This thesis is concerned with the synthesis and coordination chemistry of a range of poly(pyrazolyl)borate scorpionate' ligands and examines their suitability in facilitating rapid [11C]carbonylation reactions to form radiotracers for application in positron emission tomography (PET). The synthesis of a series of tris(pyrazolyl)borate (Tp) ligands and their corresponding copper(I) carbonyl complexes is described. The copper(I) carbonyls were formed by reaction of potassium Tp salts with copper chloride in the presence of carbon monoxide. The second part of this thesis concerns the use of a copper(I)-Tp system for selectively solubilising "CO from nitrogen-rich gas streams for subsequent use in palladium-catalysed carbonylation reactions between amines and aryl-halides to form amides. These reactions were performed on a microfluidic device and in Schlenk apparatus using unlabelled carbon monoxide. -
Kinetic and Mechanistic Study of the Reaction Between Methane Sulfonamide (CH3S(O)2NH2) and OH
Atmos. Chem. Phys., 20, 2695–2707, 2020 https://doi.org/10.5194/acp-20-2695-2020 © Author(s) 2020. This work is distributed under the Creative Commons Attribution 4.0 License. Kinetic and mechanistic study of the reaction between methane sulfonamide (CH3S.O/2NH2) and OH Matias Berasategui, Damien Amedro, Achim Edtbauer, Jonathan Williams, Jos Lelieveld, and John N. Crowley Division of Atmospheric Chemistry, Max-Planck-Institut für Chemie, 55128 Mainz, Germany Correspondence: John N. Crowley ([email protected]) Received: 8 November 2019 – Discussion started: 28 November 2019 Revised: 30 January 2020 – Accepted: 3 February 2020 – Published: 4 March 2020 Abstract. Methane sulfonamide (MSAM), CH3S.O/2NH2, The main organosulfur trace gases in the marine boundary was recently detected for the first time in ambient air over the layer are dimethyl sulfide (CH3SCH3, DMS) and its oxi- Red Sea and the Gulf of Aden where peak mixing ratios of dation products dimethyl sulfoxide (DMSO), dimethyl sul- ≈ 60 pptv were recorded. Prior to this study the rate constant fone (DMSO2), methyl sulfonic acid (MSA), and methyl for its reaction with the OH radical and the products thereby sulfinic acid (MSI) for which atmospheric lifetimes with re- formed were unknown, precluding assessment of its role in spect to their degradation by the OH radical vary between the atmosphere. We have studied the OH-initiated photo- hours (DMS) and several weeks (DMSO2). oxidation of MSAM in air (298 K, 700 Torr total pressure) Recently, the first detection of methane sulfonamide in a photochemical reactor using in situ detection of MSAM (CH3S.O/2NH2, MSAM) in ambient air was made during and its products by Fourier transform infrared (FTIR) absorp- the Air Quality and Climate Change in the Arabian Basin tion spectroscopy. -
Spectroscopy on Photografted Polyethylene Surfaces Using a Perfluorophenyl Azide: Evidence for Covalent Attachment
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by ZHAW digitalcollection Received: 30 June 2017 Revised: 30 October 2017 Accepted: 30 October 2017 DOI: 10.1002/sia.6359 RESEARCH ARTICLE Spectroscopy on photografted polyethylene surfaces using a perfluorophenyl azide: Evidence for covalent attachment Konstantin Siegmann | Jan Inauen | Robert Sterchi | Martin Winkler Institute of Materials and Process Engineering (IMPE), School of Engineering (SoE), Zurich The present study was conducted in order to confirm C―H insertion of a perfluorophenyl nitrene, University of Applied Sciences (ZHAW), produced by UV‐irradiation of a perfluorophenyl azide, to polyethylene surfaces. ‐ Technikumstrasse 9, CH 8401 Winterthur, It was shown previously that water‐repelling, oil‐repelling, and dirt‐repelling polyethylene sur- Switzerland faces can be created by “grafting to” of perfluoroalkanes using a photoreactive surface modifier Correspondence Martin Winkler, Institute of Materials and based on azide/nitrene chemistry. The abrasion resistance of the new surfaces was enhanced Process Engineering (IMPE), School of compared with a coating using a simple, long‐chain perfluoroalkane. However, covalent binding Engineering (SoE), Zurich University of Applied of the surface modifier was not unequivocally demonstrated. Sciences (ZHAW), Technikumstrasse 9, CH‐ Here, spectroscopic information is presented suggesting that, indeed, a monomolecular, cova- 8401 Winterthur, Switzerland. Email: [email protected] lently bound grafted layer is formed from the photodecomposition of a perfluorophenyl azide Funding information on polyethylene surfaces. Kommission für Technologie und Innovation, Infrared spectroscopy showed that the peak from the azide moiety disappeared upon UV‐irradi- ‐ Grant/Award Number: 17132.1 PFNM NM ation, and the light dose for completion of the photo decomposition was determined to be approximately 322 mJ/cm2. -
Strong Agostic-Type Interactions in Ruthenium Benzylidene Complexes Containing 7-Azaindole Based Scorpionate Ligands
Strong agostic-type interactions in ruthenium benzylidene complexes containing 7-azaindole based scorpionate ligands TSOUREAS, Nikolaos, NUNN, Joshua, BEVIS, Thomas, HADDOW, Mairi F., HAMILTON, Alex and OWEN, Gareth R. Available from Sheffield Hallam University Research Archive (SHURA) at: http://shura.shu.ac.uk/9925/ This document is the author deposited version. You are advised to consult the publisher's version if you wish to cite from it. Published version TSOUREAS, Nikolaos, NUNN, Joshua, BEVIS, Thomas, HADDOW, Mairi F., HAMILTON, Alex and OWEN, Gareth R. (2011). Strong agostic-type interactions in ruthenium benzylidene complexes containing 7-azaindole based scorpionate ligands. Dalton Transactions, 40 (4), 951-958. Copyright and re-use policy See http://shura.shu.ac.uk/information.html Sheffield Hallam University Research Archive http://shura.shu.ac.uk View Article Online / Journal Homepage / Table of Contents for this issue Dalton Dynamic Article Links Transactions Cite this: Dalton Trans., 2011, 40, 951 www.rsc.org/dalton PAPER Strong agostic-type interactions in ruthenium benzylidene complexes containing 7-azaindole based scorpionate ligands† Nikolaos Tsoureas, Joshua Nunn, Thomas Bevis, Mairi F. Haddow, Alex Hamilton and Gareth R. Owen*‡ Received 1st September 2010, Accepted 5th November 2010 DOI: 10.1039/c0dt01148g Ph The complexes [Ru(Tai)Cl{=C(H)Ph}(PCy3)] (4) and [Ru( Bai)Cl{=C(H)Ph}(PCy3)] (5)[whereTai = Ph HB(7-azaindolyl)3 and Bai = Ph(H)B(7-azaindolyl)2] have been prepared and structurally characterised. The borohydride unit is located in the coordination site trans to the chloride ligand in both complexes. The degree of interaction between the borohydride group and the metal centre was found to be significantly large in both cases.