1
|
Rodriguez J, Lam K, Anwar TB, Bardeen CJ. Robust Supercooled Liquid Formation Enables All-Optical Switching Between Liquid and Solid Phases of TEMPO. ACS OMEGA 2024; 9:11266-11272. [PMID: 38497006 PMCID: PMC10938447 DOI: 10.1021/acsomega.3c06717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 01/17/2024] [Accepted: 01/25/2024] [Indexed: 03/19/2024]
Abstract
Organic molecules that undergo supercooling can provide the basis for novel stimuli-responsive materials, but the number of such compounds is limited. Results in this paper show that the stable organic radical 2,2,6,6-tetramethyl-1-piperidine-1-oxyl (TEMPO) can form a stable supercooled liquid (SCL). Upon melting and cooling back to room temperature, the TEMPO SCL can persist for months, even after mild physical agitation. Its high vapor pressure can enable crystal growth at remote locations within the sample container over the course of days. Optical, electron paramagnetic resonance, and birefringence measurements show no evidence of new chemical species or partially ordered phases in the supercooled liquid. TEMPO's free radical character permits absorption of visible light that can drive photothermal melting to form the SCL, while a single nanosecond light pulse can initiate recrystallization of the SCL at some later time. This capability enables all-optical switching between the solid and the SCL phases. The physical origin of TEMPO's remarkable stability as an SCL remains an open question, but these results suggest that organic radicals comprise a new class of molecules that can form SCLs with potentially useful properties.
Collapse
Affiliation(s)
- Jacob
B. Rodriguez
- Materials
Science and Engineering, University of California,
Riverside, Riverside, California 92521, United States
| | - Kevin Lam
- Department
of Chemistry University of California, Riverside, Riverside, California 92521, United States
| | - Touhid Bin Anwar
- Department
of Chemical and Environmental Engineering University of California, Riverside, Riverside, California 92521, United States
| | - Christopher J. Bardeen
- Materials
Science and Engineering, University of California,
Riverside, Riverside, California 92521, United States
- Department
of Chemistry University of California, Riverside, Riverside, California 92521, United States
- Department
of Chemical and Environmental Engineering University of California, Riverside, Riverside, California 92521, United States
| |
Collapse
|
2
|
Wenckebach WT. Spectral diffusion of electron spin polarization in glasses doped with radicals for DNP. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2024; 360:107651. [PMID: 38430621 DOI: 10.1016/j.jmr.2024.107651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 02/24/2024] [Accepted: 02/24/2024] [Indexed: 03/05/2024]
Abstract
Spectral diffusion of electron spin polarization plays a key part in dynamic nuclear polarization (DNP). It determines the distribution of polarization across the electron spin resonance (ESR) line and consequently the polarization that is available for transfer to the nuclear spins. Various authors have studied it experimentally by means of electron-electron double resonance (ELDOR) and proposed and used macroscopic models to interpret these experiments. However, microscopic models predicting the rate of spectral diffusion are scarce. The present article is an attempt to fill this gap. It derives a spectral diffusion equation from first principles and uses Monte Carlo simulations to determine the parameters in this equation. The derivation given here builds on an observation made in a previous article on nuclear dipolar relaxation: spectral diffusion is also spatial diffusion and the random distribution of spins in space limits the former. This can be modelled assuming that rapid flip-flop transitions between a spin and its nearest neighbour do not contribute to diffusion of polarization across the ESR spectrum. The present article presents predictions of the spectral diffusion constant and shows that this limitation may lower the spectral diffusion constant by several orders of magnitude. As a check the constant is determined from first principles for a sample containing 40 mM TEMPOL. Including the limitation then results in a value that is close to that obtained from an analysis of previously reported ELDOR experiments.
Collapse
Affiliation(s)
- W Th Wenckebach
- National High Magnetic Field Laboratory, University of Florida, Gainesville, FL, USA; Paul Scherrer Institute, CH-5232, Villigen, Switzerland.
| |
Collapse
|
3
|
Abstract
Nitroxides, also known as nitroxyl radicals, are long-lived or stable radicals with the general structure R1R2N-O•. The spin distribution over the nitroxide N and O atoms contributes to the thermodynamic stability of these radicals. The presence of bulky N-substituents R1 and R2 prevents nitroxide radical dimerization, ensuring their kinetic stability. Despite their reactivity toward various transient C radicals, some nitroxides can be easily stored under air at room temperature. Furthermore, nitroxides can be oxidized to oxoammonium salts (R1R2N═O+) or reduced to anions (R1R2N-O-), enabling them to act as valuable oxidants or reductants depending on their oxidation state. Therefore, they exhibit interesting reactivity across all three oxidation states. Due to these fascinating properties, nitroxides find extensive applications in diverse fields such as biochemistry, medicinal chemistry, materials science, and organic synthesis. This review focuses on the versatile applications of nitroxides in organic synthesis. For their use in other important fields, we will refer to several review articles. The introductory part provides a brief overview of the history of nitroxide chemistry. Subsequently, the key methods for preparing nitroxides are discussed, followed by an examination of their structural diversity and physical properties. The main portion of this review is dedicated to oxidation reactions, wherein parent nitroxides or their corresponding oxoammonium salts serve as active species. It will be demonstrated that various functional groups (such as alcohols, amines, enolates, and alkanes among others) can be efficiently oxidized. These oxidations can be carried out using nitroxides as catalysts in combination with various stoichiometric terminal oxidants. By reducing nitroxides to their corresponding anions, they become effective reducing reagents with intriguing applications in organic synthesis. Nitroxides possess the ability to selectively react with transient radicals, making them useful for terminating radical cascade reactions by forming alkoxyamines. Depending on their structure, alkoxyamines exhibit weak C-O bonds, allowing for the thermal generation of C radicals through reversible C-O bond cleavage. Such thermally generated C radicals can participate in various radical transformations, as discussed toward the end of this review. Furthermore, the application of this strategy in natural product synthesis will be presented.
Collapse
Affiliation(s)
- Dirk Leifert
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, 48149 Münster, Germany
| | - Armido Studer
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, 48149 Münster, Germany
| |
Collapse
|
4
|
ANFEROV SOPHIEW, ANDERSON JOHNS. A cobalt adduct of an N-hydroxy-piperidinium cation. J COORD CHEM 2022; 75:1853-1864. [PMID: 37139469 PMCID: PMC10153568 DOI: 10.1080/00958972.2022.2119557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 08/01/2022] [Accepted: 08/10/2022] [Indexed: 10/14/2022]
Abstract
Cooperativity between organic ligands and transition metals in H-atom (proton/electron) transfer catalysis has been an important recent area of investigation. Tetramethylpiperidine-N-oxyl (TEMPO) radicals feature prominently in this area, prompting us to examine cooperativity between its hydrogenated congener, TEMPOH, and Co centers ligated by dihydrazonopyrrole ligands which have previously been shown to also store H-atom equivalents. Addition of TEMPOH to ( tBu,TolDHP)CoOTf results in formation of an unusual Co-adduct of 1-hydroxy-2,2,6,6-tetramethylpiperidin-1-ium (TEMPOH2 +) which has been characterized with IR spectroscopy and single crystal X-ray diffraction. This adduct is thermally unstable, and decomposes, putatively via N-O homolysis, to generate 2,2,6,6-tetramethylpiperidine and the Co-hydroxide complex [( tBu,TolDHP)CoOH][OTf]. Computational investigations suggest a proton-coupled electron transfer step to generate the TEMPOH2 + adduct where the Co center serves as an electron acceptor. Despite the prevalence of aminoxyl reagents in catalysis, particularly in aerobic transformations, metal complexes of differently hydrogenated congeners of TEMPO are rare. The isolation of a TEMPOH2 + adduct and investigations into its formation shed light on related transformations that may occur during metal-aminoxyl cooperative catalysis.
Collapse
Affiliation(s)
- SOPHIE W. ANFEROV
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60627, United States
| | - JOHN S. ANDERSON
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60627, United States
| |
Collapse
|
5
|
Beck AD, Haufe S, Tillmann J, Waldvogel SR. Challenges in the Electrochemical Synthesis of Si
2
Cl
6
Starting from Tetrachlorosilane and Trichlorosilane. ChemElectroChem 2022. [DOI: 10.1002/celc.202101374] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Alexander D. Beck
- Consortium für elektrochemische Industrie Wacker Chemie AG Zielstattstraße 20 81379 München Germany
- Department Chemie Johannes Gutenberg-Universität Mainz Duesbergweg 10–14 55128 Mainz Germany
| | - Stefan Haufe
- Consortium für elektrochemische Industrie Wacker Chemie AG Zielstattstraße 20 81379 München Germany
| | - Jan Tillmann
- Consortium für elektrochemische Industrie Wacker Chemie AG Zielstattstraße 20 81379 München Germany
| | - Siegfried R. Waldvogel
- Department Chemie Johannes Gutenberg-Universität Mainz Duesbergweg 10–14 55128 Mainz Germany
| |
Collapse
|
6
|
Golovanov I, Leonov A, Lesnikov V, Pospelov E, Frolov KV, Korlyukov A, Nelyubina YV, Novikov VV, Sukhorukov AY. Iron(IV) Complexes with Tetraazaadamantane-based Ligands: Synthesis, Structure, Application in Dioxygen Activation and Labeling of Biomolecules. Dalton Trans 2022; 51:4284-4296. [DOI: 10.1039/d1dt04104e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
4,6,10-Trihydroxy-1,4,6,10-tetraazaadamantane (TAAD) has been shown to form a stable Fe(IV) complex having a diamantane cage structure, in which the metal center is coordinated by three oxygen atoms of the deprotonated...
Collapse
|
7
|
Sahana T, Mondal A, Anju BS, Kundu S. Metal-free Transformations of Nitrogen-Oxyanions to Ammonia via Oxoammonium Salt. Angew Chem Int Ed Engl 2021; 60:20661-20665. [PMID: 34057773 DOI: 10.1002/anie.202105723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Indexed: 11/09/2022]
Abstract
Transformations of nitrogen-oxyanions (NOx - ) to ammonia impart pivotal roles in sustainable biogeochemical processes. While metal-mediated reductions of NOx - are relatively well known, this report illustrates proton-assisted transformations of NOx - anions in the presence of electron-rich aromatics such as 1,3,5-trimethoxybenzene (TMB-H, 1 a) leading to the formation of diaryl oxoammonium salt [(TMB)2 N+ =O][NO3 - ] (2 a) via the intermediacy of nitrosonium cation (NO+ ). Detailed characterizations including UV/Vis, multinuclear NMR, FT-IR, HRMS, X-ray analyses on a set of closely related metastable diaryl oxoammonium [Ar2 N+ =O] species disclose unambiguous structural and spectroscopic signatures. Oxoammonium salt 2 a exhibits 2 e- oxidative reactivity in the presence of oxidizable substrates such as benzylamine, thiol, and ferrocene. Intriguingly, reaction of 2 a with water affords ammonia. Perhaps of broader significance, this work reveals a new metal-free route germane to the conversion of NOx to NH3 .
Collapse
Affiliation(s)
- Tuhin Sahana
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER-TVM), Thiruvananthapuram, 695551, India
| | - Aditesh Mondal
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER-TVM), Thiruvananthapuram, 695551, India
| | - Balakrishnan S Anju
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER-TVM), Thiruvananthapuram, 695551, India
| | - Subrata Kundu
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER-TVM), Thiruvananthapuram, 695551, India
| |
Collapse
|
8
|
Sahana T, Mondal A, Anju BS, Kundu S. Metal‐free Transformations of Nitrogen‐Oxyanions to Ammonia via Oxoammonium Salt. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202105723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Tuhin Sahana
- School of Chemistry Indian Institute of Science Education and Research Thiruvananthapuram (IISER-TVM) Thiruvananthapuram 695551 India
| | - Aditesh Mondal
- School of Chemistry Indian Institute of Science Education and Research Thiruvananthapuram (IISER-TVM) Thiruvananthapuram 695551 India
| | - Balakrishnan S. Anju
- School of Chemistry Indian Institute of Science Education and Research Thiruvananthapuram (IISER-TVM) Thiruvananthapuram 695551 India
| | - Subrata Kundu
- School of Chemistry Indian Institute of Science Education and Research Thiruvananthapuram (IISER-TVM) Thiruvananthapuram 695551 India
| |
Collapse
|
9
|
Carlet F, Bertarini G, Broggini G, Pradal A, Poli G. Oxoammonium‐Mediated Allylsilane–Ether Coupling Reaction. European J Org Chem 2021. [DOI: 10.1002/ejoc.202100026] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Federica Carlet
- Faculté des Sciences et Ingénierie CNRS Institut Parisien de Chimie Moléculaire IPCM Sorbonne Université 4 place Jussieu 75005 Paris France
- Dipartimento di Scienza e Alta Tecnologia Università dell'Insubria Via Valleggio 11 22100 Como Italy
| | - Greta Bertarini
- Faculté des Sciences et Ingénierie CNRS Institut Parisien de Chimie Moléculaire IPCM Sorbonne Université 4 place Jussieu 75005 Paris France
- Dipartimento di Scienza e Alta Tecnologia Università dell'Insubria Via Valleggio 11 22100 Como Italy
| | - Gianluigi Broggini
- Dipartimento di Scienza e Alta Tecnologia Università dell'Insubria Via Valleggio 11 22100 Como Italy
| | - Alexandre Pradal
- Faculté des Sciences et Ingénierie CNRS Institut Parisien de Chimie Moléculaire IPCM Sorbonne Université 4 place Jussieu 75005 Paris France
| | - Giovanni Poli
- Faculté des Sciences et Ingénierie CNRS Institut Parisien de Chimie Moléculaire IPCM Sorbonne Université 4 place Jussieu 75005 Paris France
| |
Collapse
|
10
|
Rybkin VV, VandeVondele J. Spin-Unrestricted Second-Order Møller–Plesset (MP2) Forces for the Condensed Phase: From Molecular Radicals to F-Centers in Solids. J Chem Theory Comput 2016; 12:2214-23. [DOI: 10.1021/acs.jctc.6b00015] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Vladimir V. Rybkin
- Nanoscale Simulations, Department
of Materials, ETH Zürich, Wolfgang-Pauli-Str. 27, CH-8093 Zürich, Switzerland
| | - Joost VandeVondele
- Nanoscale Simulations, Department
of Materials, ETH Zürich, Wolfgang-Pauli-Str. 27, CH-8093 Zürich, Switzerland
| |
Collapse
|
11
|
Judith Percino M, Cerón M, Soriano-Moro G, Pacheco JA, Eugenia Castro M, Chapela VM, Bonilla-Cruz J, Saldivar-Guerra E. 2,2,6,6-Tetramethyl-1-oxopiperidinetribromide and two forms of 1-hydroxy-2,2,6,6-tetramethylpiperidinium bromide salt: Syntheses, crystal structures and theoretical calculations. J Mol Struct 2016. [DOI: 10.1016/j.molstruc.2015.09.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
12
|
Yao W, Kelley SP, Rogers RD, Vaid TP. Electrical conductivity in two mixed-valence liquids. Phys Chem Chem Phys 2015; 17:14107-14. [PMID: 25960288 DOI: 10.1039/c5cp01172h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Two different room-temperature liquid systems were investigated, both of which conduct a DC electrical current without decomposition or net chemical transformation. DC electrical conductivity is possible in both cases because of the presence of two different oxidation states of a redox-active species. One system is a 1 : 1 molar mixture of n-butylferrocene (BuFc) and its cation bis(trifluoromethane)sulfonimide salt, [BuFc(+)][NTf2(-)], while the other is a 1 : 1 molar mixture of TEMPO and its cation bis(trifluoromethane)sulfonimide salt, [TEMPO(+)][NTf2(-)]. The TEMPO-[TEMPO(+)][NTf2(-)] system is notable in that it is an electrically conducting liquid in which the conductivity originates from an organic molecule in two different oxidation states, with no metals present. Single-crystal X-ray diffraction of [TEMPO(+)][NTf2(-)] revealed a complex structure with structurally different cation-anion interactions for cis- and trans [NTf2(-)] conformers. The electron transfer self-exchange rate constant for BuFc/BuFc(+) in CD3CN was determined by (1)H NMR spectroscopy to be 5.4 × 10(6) M(-1) s(-1). The rate constant allowed calculation of an estimated electrical conductivity of 7.6 × 10(-5)Ω(-1) cm(-1) for BuFc-[BuFc(+)][NTf2(-)], twice the measured value of 3.8 × 10(-5)Ω(-1) cm(-1). Similarly, a previously reported self-exchange rate constant for TEMPO/TEMPO(+) in CH3CN led to an estimated conductivity of 1.3 × 10(-4)Ω(-1) cm(-1) for TEMPO-[TEMPO(+)][NTf2(-)], a factor of about 3 higher than the measured value of 4.3 × 10(-5)Ω(-1) cm(-1).
Collapse
Affiliation(s)
- Wenzhi Yao
- Department of Chemistry, The University of Alabama, Tuscaloosa, Alabama 35487, USA.
| | | | | | | |
Collapse
|
13
|
Budnyak TM, Pylypchuk IV, Tertykh VA, Yanovska ES, Kolodynska D. Synthesis and adsorption properties of chitosan-silica nanocomposite prepared by sol-gel method. NANOSCALE RESEARCH LETTERS 2015; 10:87. [PMID: 25852383 PMCID: PMC4385279 DOI: 10.1186/s11671-014-0722-1] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 12/29/2014] [Indexed: 05/25/2023]
Abstract
A hybrid nanocomposite material has been obtained by in situ formation of an inorganic network in the presence of a preformed organic polymer. Chitosan biopolymer and tetraethoxysilane (TEOS), which is the most common silica precursor, were used for the sol-gel reaction. The obtained composite chitosan-silica material has been characterized by physicochemical methods such as differential thermal analyses (DTA); carbon, hydrogen, and nitrogen (CHN) elemental analysis; nitrogen adsorption/desorption isotherms, scanning electron microscopy (SEM); and Fourier transform infrared (FTIR) spectroscopy to determine possible interactions between silica and chitosan macromolecules. Adsorption of microquantities of V(V), Mo(VI), and Cr(VI) oxoanions from the aqueous solutions by the obtained composite has been studied in comparison with the chitosan beads, previously crosslinked with glutaraldehyde. The adsorption capacity and kinetic sorption characteristics of the composite material were estimated.
Collapse
Affiliation(s)
- Tetyana M Budnyak
- />Chuiko Institute of Surface Chemistry of National Academy of Sciences of Ukraine, 17 General Naumov Str., 03164 Kyiv, Ukraine
| | - Ievgen V Pylypchuk
- />Chuiko Institute of Surface Chemistry of National Academy of Sciences of Ukraine, 17 General Naumov Str., 03164 Kyiv, Ukraine
| | - Valentin A Tertykh
- />Chuiko Institute of Surface Chemistry of National Academy of Sciences of Ukraine, 17 General Naumov Str., 03164 Kyiv, Ukraine
| | - Elina S Yanovska
- />Faculty of Chemistry, Taras Shevchenko National University of Kyiv, 64 Volodymyrska Str., 01033 Kyiv, Ukraine
| | - Dorota Kolodynska
- />Faculty of Chemistry, Maria Curie Skłodowska University, M. Curie Skłodowska Sq. 2, 20-031 Lublin, Poland
| |
Collapse
|
14
|
Percino J, Pacheco JA, Soriano-Moro G, Cerón M, Castro ME, Chapela VM, Bonilla-Cruz J, Lara-Ceniceros TE, Flores-Guerrero M, Saldivar-Guerra E. Synthesis, characterization and theoretical calculations of model compounds of silanols catalyzed by TEMPO to elucidate the presence of Si–O–Si and Si–O–N bonds. RSC Adv 2015. [DOI: 10.1039/c5ra10056a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We report the results from the reactions of 1-phenylethanol, 2-methylpropanol, trimethylsilanol and triphenylsilanol with TEMPO, OH-TEMPO and Br-TEMPO salt at different reaction conditions to obtain model functionalized compounds.
Collapse
Affiliation(s)
- Judith Percino
- Lab. de Polímeros
- Centro de Química
- Instituto de Ciencias
- Benemérita Universidad Autónoma de Puebla
- C.P. 72570 Puebla
| | - José A. Pacheco
- Lab. de Polímeros
- Centro de Química
- Instituto de Ciencias
- Benemérita Universidad Autónoma de Puebla
- C.P. 72570 Puebla
| | - Guillermo Soriano-Moro
- Lab. de Polímeros
- Centro de Química
- Instituto de Ciencias
- Benemérita Universidad Autónoma de Puebla
- C.P. 72570 Puebla
| | - Margarita Cerón
- Lab. de Polímeros
- Centro de Química
- Instituto de Ciencias
- Benemérita Universidad Autónoma de Puebla
- C.P. 72570 Puebla
| | - M. Eugenia Castro
- Lab. de Polímeros
- Centro de Química
- Instituto de Ciencias
- Benemérita Universidad Autónoma de Puebla
- C.P. 72570 Puebla
| | - Víctor M. Chapela
- Lab. de Polímeros
- Centro de Química
- Instituto de Ciencias
- Benemérita Universidad Autónoma de Puebla
- C.P. 72570 Puebla
| | - José Bonilla-Cruz
- Cento de Investigación en Materiales Avanzados S.C. (CIMAV-Unidad Monterrey)
- C.P. 66600 Apodaca
- Mexico
| | - Tania E. Lara-Ceniceros
- Cento de Investigación en Materiales Avanzados S.C. (CIMAV-Unidad Monterrey)
- C.P. 66600 Apodaca
- Mexico
| | - Mildred Flores-Guerrero
- Cento de Investigación en Materiales Avanzados S.C. (CIMAV-Unidad Monterrey)
- C.P. 66600 Apodaca
- Mexico
| | | |
Collapse
|
15
|
Nguyen TAD, Wright AM, Page JS, Wu G, Hayton TW. Oxidation of Alcohols and Activated Alkanes with Lewis Acid-Activated TEMPO. Inorg Chem 2014; 53:11377-87. [DOI: 10.1021/ic5018888] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Thuy-Ai D. Nguyen
- Department of Chemistry and
Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Ashley M. Wright
- Department of Chemistry and
Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Joshua S. Page
- Department of Chemistry and
Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Guang Wu
- Department of Chemistry and
Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Trevor W. Hayton
- Department of Chemistry and
Biochemistry, University of California, Santa Barbara, California 93106, United States
| |
Collapse
|
16
|
Jochmann P, Stephan DW. The synthesis and structure of [Zn(TEMPO)2]2 and [Zn(μ-H)(μ2-η1:η1-TEMPO)]6. Chem Commun (Camb) 2014; 50:8395-7. [DOI: 10.1039/c4cc03256j] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The commercially available radical TEMPO (2,2,6,6-tetramethylpiperidin-1-yloxy) reacts with [ZnCp*2] (1) to yield the homoleptic compound [Zn(TEMPO)2]2 (2) through coupling of two Cp* radicals. Compound 1 reacts with H2 to afford the hydride complex [Zn(μ-H)(μ2-η1-η1-TEMPO)]6 (3) featuring a planar Zn6H6 ring in the solid state.
Collapse
|
17
|
Fang H, Ling Z, Lang K, Brothers PJ, de Bruin B, Fu X. Germanium(iii) corrole complex: reactivity and mechanistic studies of visible-light promoted N–H bond activations. Chem Sci 2014. [DOI: 10.1039/c3sc52326h] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
|
18
|
Mondal KC, Roesky HW, Stückl AC, Ehret F, Kaim W, Dittrich B, Maity B, Koley D. Formation of Trichlorosilyl-Substituted Carbon-Centered Stable Radicals through the Use of π-Accepting Carbenes. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201300668] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
19
|
Mondal KC, Roesky HW, Stückl AC, Ehret F, Kaim W, Dittrich B, Maity B, Koley D. Formation of Trichlorosilyl-Substituted Carbon-Centered Stable Radicals through the Use of π-Accepting Carbenes. Angew Chem Int Ed Engl 2013; 52:11804-7. [DOI: 10.1002/anie.201300668] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 07/24/2013] [Indexed: 11/09/2022]
|
20
|
Wright AM, Page JS, Scepaniak JJ, Wu G, Hayton TW. Divergent Reactivity of TEMPO with MBr3(M = B, Al). Eur J Inorg Chem 2013. [DOI: 10.1002/ejic.201300163] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
21
|
Levason W, Pugh D, Reid G. Phosphine and Diphosphine Complexes of Silicon(IV) Halides. Inorg Chem 2013; 52:5185-93. [DOI: 10.1021/ic400077z] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- William Levason
- School of Chemistry, University of Southampton, Southampton, SO17 1BJ, U.K
| | - David Pugh
- School of Chemistry, University of Southampton, Southampton, SO17 1BJ, U.K
| | - Gillian Reid
- School of Chemistry, University of Southampton, Southampton, SO17 1BJ, U.K
| |
Collapse
|
22
|
Tuning the reactivity of TEMPO by coordination to a Lewis acid: isolation and reactivity of MCl3(η1-TEMPO) (M = Fe, Al). J Am Chem Soc 2012; 134:19350-3. [PMID: 23134421 DOI: 10.1021/ja309499h] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Addition of 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) to MCl(3) (M = Fe, Al) results in the formation of MCl(3)(η(1)-TEMPO) [M = Fe (1), Al (2)]. Both 1 and 2 oxidize alcohols to generate ketones or aldehydes along with the reduced complexes MCl(3)(η(1)-TEMPOH) [M = Fe (3), Al (4)]. Complexes 1-4 were fully characterized, including analysis by X-ray crystallography. Additionally, control experiments indicated that neither MCl(3) (M = Al, Fe) nor TEMPO are capable of effecting the oxidation of alcohols independently.
Collapse
|
23
|
Sonobe T, Oisaki K, Kanai M. Catalytic aerobic production of imines en route to mild, green, and concise derivatizations of amines. Chem Sci 2012. [DOI: 10.1039/c2sc20699d] [Citation(s) in RCA: 174] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
|
24
|
George K, Hector AL, Levason W, Reid G, Sanderson G, Webster M, Zhang W. Hypervalent neutral O-donor ligand complexes of silicon tetrafluoride, comparisons with other group 14 tetrafluorides and a search for soft donor ligand complexes. Dalton Trans 2011; 40:1584-93. [DOI: 10.1039/c0dt01115k] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|