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Tejeda G, Belov DS, Fenoll DA, Rue KL, Tsay C, Solans-Monfort X, Bukhryakov KV. Vanadium Imido NHC Complexes for Ring-Closing Olefin Metathesis Reactions. Organometallics 2022. [DOI: 10.1021/acs.organomet.2c00013] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Gabriela Tejeda
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
| | - Dmitry S. Belov
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
| | - Didac A. Fenoll
- Departament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Kelly L. Rue
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
| | - Charlene Tsay
- Department of Chemistry, University of California, Riverside, California 92591, United States
| | | | - Konstantin V. Bukhryakov
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
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2
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Liu S, Boudjelel M, Schrock RR, Conley MP, Tsay C. Interconversion of Molybdenum or Tungsten d 2 Styrene Complexes with d 0 1-Phenethylidene Analogues. J Am Chem Soc 2021; 143:17209-17218. [PMID: 34633807 DOI: 10.1021/jacs.1c08086] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Upon addition of 5-15% PhNMe2H+X- (X = B(3,5-(CF3)2C6H3)4 or B(C6F5)4) to Mo(NAr)(styrene)(OSiPh3)2 (Ar = N-2,6-i-Pr2C6H3) in C6D6 an equilibrium mixture of Mo(NAr)(styrene)(OSiPh3)2 and Mo(NAr)(CMePh)(OSiPh3)2 is formed over 36 h at 45 °C (Keq = 0.36). A plausible intermediate in the interconversion of the styrene and 1-phenethylidene complexes is the 1-phenethyl cation, [Mo(NAr)(CHMePh)(OSiPh3)2]+, which can be generated using [(Et2O)2H][B(C6F5)4] as the acid. The interconversion can be modeled as two equilibria involving protonation of Mo(NAr)(styrene)(OSiPh3)2 or Mo(NAr)(CMePh)(OSiPh3)2 and deprotonation of the α or β phenethyl carbon atom in [Mo(NAr)(CHMePh)(OSiPh3)2]+. The ratio of the rate of deprotonation of [Mo(NAr)(CHMePh)(OSiPh3)2]+ by PhNMe2 in the α position versus the β position is ∼10, or ∼30 per Hβ. The slow step is protonation of Mo(NAr)(styrene)(OSiPh3)2 (k1 = 0.158(4) L/(mol·min)). Proton sources such as (CF3)3COH or Ph3SiOH do not catalyze the interconversion of Mo(NAr)(styrene)(OSiPh3)2 and Mo(NAr)(CMePh)(OSiPh3)2, while the reaction of Mo(NAr)(styrene)(OSiPh3)2 with pyridinium salts generates only a trace (∼2%) of Mo(NAr)(CMePh)(OSiPh3)2 and forms a monopyridine adduct, [Mo(NAr)(CHMePh)(OSiPh3)2(py)]+ (two diastereomers). The structure of [Mo(NAr)(CHMePh)(OSiPh3)2]+ has been confirmed in an X-ray study; there is no structural indication that a β proton is activated through a CHβ interaction with the metal. W(NAr)(CMePh)(OSiPh3)2 is also converted into a mixture of W(NAr)(CMePh)(OSiPh3)2 and W(NAr)(styrene)(OSiPh3)2 (Keq = 0.47 at 45 °C in favor of the styrene complex) with 10% [PhNMe2H][B(C6F5)4] as the catalyst; the time required to reach equilibrium is approximately the same as in the Mo system.
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Affiliation(s)
- Sumeng Liu
- Department of Chemistry, University of California at Riverside, Riverside, California 92521, United States
| | - Maxime Boudjelel
- Department of Chemistry, University of California at Riverside, Riverside, California 92521, United States
| | - Richard R Schrock
- Department of Chemistry, University of California at Riverside, Riverside, California 92521, United States
| | - Matthew P Conley
- Department of Chemistry, University of California at Riverside, Riverside, California 92521, United States
| | - Charlene Tsay
- Department of Chemistry, University of California at Riverside, Riverside, California 92521, United States
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Paul B, Schrock RR, Tsay C. Synthesis of Cationic Molybdenum Imido 2-Adamantylidene Complexes from Bispyrrolides via Cationic Pyrrolenine Complexes. Organometallics 2021. [DOI: 10.1021/acs.organomet.1c00415] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Bhaskar Paul
- Department of Chemistry, University of California at Riverside, Riverside, California 92521, United States
| | - Richard R. Schrock
- Department of Chemistry, University of California at Riverside, Riverside, California 92521, United States
| | - Charlene Tsay
- Department of Chemistry, University of California at Riverside, Riverside, California 92521, United States
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4
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Wen X, Zhang J, Luo H, Shi J, Tsay C, Jiang H, Lin YH, Schroeder MA, Xu K, Guo J. Synthesis and Electrochemical Properties of Aluminum Hexafluorophosphate. J Phys Chem Lett 2021; 12:5903-5908. [PMID: 34152154 DOI: 10.1021/acs.jpclett.1c01236] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We report the first synthesis of aluminum hexafluorophosphate (Al(PF6)3) and its electrochemical properties in dimethyl sulfoxide (DMSO). The single crystal structure of the synthesized Al(PF6)3 is revealed as [Al(DMSO)6](PF6)3, and 0.25 M Al(PF6)3 in DMSO with high ionic conductivity is obtained. The purity of this electrolyte was further confirmed with nuclear magnetic resonance spectroscopy and electrospray ionization mass spectrometry. We then demonstrated the reversibility of Al deposition-stripping in this electrolyte using scanning electron microscopy and an X-ray photoelectron spectroscopy depth profiling study. The parasitic reaction involving DMSO decomposition during Al deposition is also identified via gas chromatography/electron ionization mass spectrometry.
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Affiliation(s)
| | | | - Hewei Luo
- School of Material and Chemical Engineering, Zhengzhou University of Light Industry, Zhengzhou 450002, China
| | | | | | | | | | - Marshall A Schroeder
- Energy Sciences Division, US Army Research Laboratory, Adelphi, Maryland 20783, United States
| | - Kang Xu
- Energy Sciences Division, US Army Research Laboratory, Adelphi, Maryland 20783, United States
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Affiliation(s)
- Maxime Boudjelel
- Department of Chemistry, University of California at Riverside, Riverside, California 92521, United States
| | - Feng Zhai
- Department of Chemistry 6-331, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Richard R. Schrock
- Department of Chemistry 6-331, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Department of Chemistry, University of California at Riverside, Riverside, California 92521, United States
| | - Amir H. Hoveyda
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Charlene Tsay
- Department of Chemistry, University of California at Riverside, Riverside, California 92521, United States
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Affiliation(s)
- Bhaskar Paul
- Department of Chemistry, University of California at Riverside, Riverside, California 92521, United States
| | - Richard R. Schrock
- Department of Chemistry, University of California at Riverside, Riverside, California 92521, United States
| | - Charlene Tsay
- Department of Chemistry, University of California at Riverside, Riverside, California 92521, United States
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7
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Belov DS, Tejeda G, Tsay C, Bukhryakov KV. Ring‐Closing Olefin Metathesis Catalyzed by Well‐Defined Vanadium Alkylidene Complexes. Chemistry 2021; 27:4578-4582. [DOI: 10.1002/chem.202005438] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Indexed: 02/03/2023]
Affiliation(s)
- Dmitry S. Belov
- Department of Chemistry and Biochemistry Florida International University 11200 SW 8th St. Miami FL 33199 USA
| | - Gabriela Tejeda
- Department of Chemistry and Biochemistry Florida International University 11200 SW 8th St. Miami FL 33199 USA
| | - Charlene Tsay
- Department of Chemistry University of California Riverside CA 92521 USA
| | - Konstantin V. Bukhryakov
- Department of Chemistry and Biochemistry Florida International University 11200 SW 8th St. Miami FL 33199 USA
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8
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Affiliation(s)
- Jordan W. Taylor
- Department of Chemistry, University of California at Riverside, Riverside, California 92521, United States
| | - Richard R. Schrock
- Department of Chemistry, University of California at Riverside, Riverside, California 92521, United States
| | - Charlene Tsay
- Department of Chemistry, University of California at Riverside, Riverside, California 92521, United States
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Tafazolian H, VenkatRamani S, Tsay C, Schrock RR, Müller P. Syntheses of Molybdenum and Tungsten Imido Alkylidene Complexes that Contain a Bidentate Oxo/Thiolato Ligand. Helv Chim Acta 2020. [DOI: 10.1002/hlca.202000068] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Hosein Tafazolian
- Department of Chemistry Massachusetts Institute of Technology Cambridge, Massachusetts 02139 USA
- Department of Chemistry University of California at Riverside Riverside, California 92507 USA
| | - Sudarsan VenkatRamani
- Department of Chemistry Massachusetts Institute of Technology Cambridge, Massachusetts 02139 USA
| | - Charlene Tsay
- Department of Chemistry University of California at Riverside Riverside, California 92507 USA
| | - Richard R. Schrock
- Department of Chemistry Massachusetts Institute of Technology Cambridge, Massachusetts 02139 USA
- Department of Chemistry University of California at Riverside Riverside, California 92507 USA
| | - Peter Müller
- Department of Chemistry Massachusetts Institute of Technology Cambridge, Massachusetts 02139 USA
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10
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Dresselhaus-Cooper LE, Martynowych DJ, Zhang F, Tsay C, Ilavsky J, Wang SG, Chen YS, Nelson KA. Pressure-Thresholded Response in Cylindrically Shocked Cyclotrimethylene Trinitramine (RDX). J Phys Chem A 2020; 124:3301-3313. [PMID: 32009390 DOI: 10.1021/acs.jpca.9b07637] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We demonstrate a strongly thresholded response in cyclotrimethylene trinitramine (RDX) when it is cylindrically shocked using a novel waveguide geometry. Using ultrafast single-shot multi-frame imaging, we demonstrate that <100 μm diameter single crystals of RDX embedded in a polymer host deform along preferential planes for >100 ns after the shock first arrives in the crystal. We use in situ imaging and time-resolved photoemission to demonstrate that short-lived chemistry occurs with complex deformation pathways. Using scanning electron microscopy and ultra-small-angle X-ray scattering, we demonstrate that the shock-induced dynamics leave behind porous crystals, with pore shapes and sizes that change significantly with shock pressure. A threshold pressure of ∼12 GPa at the center of convergence separated the single-mode planar crystal deformations from the chemistry-coupled multi-plane dynamics at higher pressures. Our observations indicate preferential directions for deformation in our cylindrically shocked system, despite the applied stress along many different crystallographic planes.
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Affiliation(s)
- Leora E Dresselhaus-Cooper
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States.,Institute for Soldier Nanotechnology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Dmitro J Martynowych
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States.,Institute for Soldier Nanotechnology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Fan Zhang
- Materials Measurement Science Division, National Institute of Standards and Technology, 100 Bureau Dr., Gaithersburg, Maryland 20899, United States
| | - Charlene Tsay
- Department of Chemistry, University of California Riverside, 501 Big Springs Rd., Riverside, California 92521, United States
| | - Jan Ilavsky
- X-ray Science Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439, United States
| | - SuYin Grass Wang
- ChemMatCARS, Center for Advanced Radiation Sources, The University of Chicago, 9700 S. Cass Avenue, Argonne, Illinois 60439, United States
| | - Yu-Sheng Chen
- ChemMatCARS, Center for Advanced Radiation Sources, The University of Chicago, 9700 S. Cass Avenue, Argonne, Illinois 60439, United States
| | - Keith A Nelson
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States.,Institute for Soldier Nanotechnology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
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Affiliation(s)
- Jordan W. Taylor
- Department of Chemistry, University of California at Riverside, Riverside, California 92521, United States
| | - Richard R. Schrock
- Department of Chemistry, University of California at Riverside, Riverside, California 92521, United States
| | - Charlene Tsay
- Department of Chemistry, University of California at Riverside, Riverside, California 92521, United States
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12
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Fisher SP, McArthur SG, Tej V, Lee SE, Chan AL, Banda I, Gregory A, Berkley K, Tsay C, Rheingold AL, Guisado-Barrios G, Lavallo V. Strongly Coordinating Ligands To Form Weakly Coordinating Yet Functional Organometallic Anions. J Am Chem Soc 2019; 142:251-256. [PMID: 31804820 DOI: 10.1021/jacs.9b10234] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Weakly coordinating anions (WCAs) are generally tailored to act as spectators with little or no function. Here we describe the implementation of strongly coordinating dianionic carboranyl N-heterocyclic carbenes (NHCs) to create organometallic -ate complexes of Au(I) that serve both as WCAs and functional catalysts. These organometallic WCAs can be utilized to form both heterobimetallic (Au(I)-/Ag(I)+; Au(I)-/Ir(I)+) and organometallic/main group ion pairs (Au(I)-/(CPh3+ or SiEt3+). Because parent unfunctionalized dianionic carboranyl NHC complex 3 is unstable in most solvents when paired with CPh3+, novel synthesis methodology was devised to create polyhalogenated carboranyl NHCs, which show superior stability toward electrophilic substitution and cyclometalation chemistry. Additionally, the WCAs containing polyhalogenated carboranyl NHCs are among the most active catalysts reported for the hydroamination of alkynes. This investigation has also produced the first examples of a low-coordinate Au(III) center with two cis accessible coordination sites and the first true dianionic carbene. These studies pave the way for the design of functional ion pairs that have the potential to participate in tandem or cooperative small-molecule activation and catalysis.
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Affiliation(s)
- Steven P Fisher
- Department of Chemistry and Center for Catalysis , University of California-Riverside , Riverside , California 92521 , United States
| | - Scott G McArthur
- Department of Chemistry and Center for Catalysis , University of California-Riverside , Riverside , California 92521 , United States
| | - Varun Tej
- Department of Chemistry and Center for Catalysis , University of California-Riverside , Riverside , California 92521 , United States
| | - Sarah E Lee
- Department of Chemistry and Center for Catalysis , University of California-Riverside , Riverside , California 92521 , United States
| | - Allen L Chan
- Department of Chemistry and Center for Catalysis , University of California-Riverside , Riverside , California 92521 , United States
| | - Isaac Banda
- Department of Chemistry and Center for Catalysis , University of California-Riverside , Riverside , California 92521 , United States
| | - Aaron Gregory
- Department of Chemistry and Center for Catalysis , University of California-Riverside , Riverside , California 92521 , United States
| | - Kevin Berkley
- Department of Chemistry and Center for Catalysis , University of California-Riverside , Riverside , California 92521 , United States
| | - Charlene Tsay
- Department of Chemistry and Center for Catalysis , University of California-Riverside , Riverside , California 92521 , United States
| | - Arnold L Rheingold
- Department of Chemistry and Biochemistry , University of California-San Diego , La Jolla , California 92093 , United States
| | - Gregorio Guisado-Barrios
- Institute of Advanced Materials (INAM) , Universitat Jaume I , Avda. Vicente Sos Baynat s/n , Castellón E-12071 , Spain
| | - Vincent Lavallo
- Department of Chemistry and Center for Catalysis , University of California-Riverside , Riverside , California 92521 , United States
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Hickey AK, Wickramasinghe LA, Schrock RR, Tsay C, Müller P. Protonation Studies of Molybdenum(VI) Nitride Complexes That Contain the [2,6-(ArNCH 2) 2NC 5H 3] 2- Ligand (Ar = 2,6-Diisopropylphenyl). Inorg Chem 2019; 58:3724-3731. [PMID: 30807124 DOI: 10.1021/acs.inorgchem.8b03346] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[Ar2N3]Mo(N)(O- t-Bu) (1), which contains the conformationally rigid pyridine-based diamido ligand [2,6-(ArNCH2)2NC5H3]2- (Ar = 2,6-diisopropylphenyl), is a catalyst for the reduction of dinitrogen with protons and electrons. Various acids have been added in order to explore where and how the first proton adds to the complex. The addition of adamantol to 1 produces a five-coordinate bis(adamantoxide), [HAr2N3]Mo(N)(OAd)2 (2a), in which one of the amido nitrogens in the ligand has been protonated and the resulting aniline nitrogen in the [HAr2N3]- ligand is not bound to the metal. The addition of [Ph2NH2][OTf] to 1 produces {[HAr2N3]Mo(N)(O- t-Bu)}(OTf) (3), in which an amido nitrogen has been protonated, but the aniline in the [HAr2N3]- ligand remains bound to the metal. Last, the addition of (2,6-lutidinium)BArF4 (BArF4 = {B(3,5-(CF3)2C6H3)4}-) to 1 yields {[Ar2N3]Mo(N)(LutH)(O- t-Bu)}BArF4, in which LutH+ is hydrogen-bonded to the nitride in the solid state and in dichloromethane with Keq = 412 ± 94 and Δ G = -3.6 ± 0.8 kcal at 22 °C. A similar hydrogen-bonded adduct was formed through the addition of (2-methylpyridinium)BArF4 to 1, but the addition of (pyridinium)BArF4 to 1 leads to the formation of (inter alia) {[HAr2N3]Mo(N)(O- t-Bu)}(BArF4), in which the amide nitrogen has been protonated. The addition of cobaltocene to 3 or {[Ar2N3]Mo(N)(LutH)(O- t-Bu)}(BArF4) leads only to the re-formation of 1. X-ray structural studies were carried out on 2a, 3, and {[Ar2N3]Mo(N)(LutH)(O- t-Bu)}(BArF4).
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Affiliation(s)
- Anne K Hickey
- Department of Chemistry , Massachusetts Institute of Technology , 77 Massachusetts Avenue , Cambridge , Massachusetts 02139 , United States
| | - Lasantha A Wickramasinghe
- Department of Chemistry , Massachusetts Institute of Technology , 77 Massachusetts Avenue , Cambridge , Massachusetts 02139 , United States
| | - Richard R Schrock
- Department of Chemistry , Massachusetts Institute of Technology , 77 Massachusetts Avenue , Cambridge , Massachusetts 02139 , United States
| | - Charlene Tsay
- Department of Chemistry , Massachusetts Institute of Technology , 77 Massachusetts Avenue , Cambridge , Massachusetts 02139 , United States
| | - Peter Müller
- Department of Chemistry , Massachusetts Institute of Technology , 77 Massachusetts Avenue , Cambridge , Massachusetts 02139 , United States
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Wickramasinghe LA, Schrock RR, Tsay C, Müller P. Molybdenum Complexes that Contain a Calix[6]azacryptand Ligand as Catalysts for Reduction of N 2 to Ammonia. Inorg Chem 2018; 57:15566-15574. [PMID: 30516366 DOI: 10.1021/acs.inorgchem.8b02903] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
[CAC(OMe)6]Mo(N) (3, where [CAC]3- is a calix[6]azacryptand ligand derived from a [6]calixarene) has been prepared in a reaction between Li3[CAC(OMe)6] and ( t-BuO)3Mo(N). An X-ray structural study showed 3 to have a structure similar to that of [HIPTN3N]Mo(N) (where [HIPTN3N]3- is [(3,5-(2,4,6-triisopropylphenyl)2C6H3NCH2CH2)3N]3-). The relatively rigid [CAC(OMe)6]3- ligand in 3 forms a bowl-shaped cavity defined by a 24-atom macrocyclic ring. The Mo-Namido-Cipso angles are ∼8° smaller in 3 than they are in [HIPTN3N]Mo(N). Methoxides on the three linking units point into the cavity above the nitride in 3, whereas the three methoxides on phenyl rings attached to the amido nitrogen atoms point away from the cavity. An analogous [CAC(OMe)3(H)3]Mo(N) complex (9) was prepared in which the three methoxides pointing into the cavity in 3 have been replaced by protons. Its structure differs little from that of 3. The nitride could be protonated in 3 to give {[CAC(OMe)6]Mo(NH)}+, which could be reduced (reversibly) to [CAC(OMe)6]Mo(NH). Catalytic reduction of molecular nitrogen under a variety of conditions with either Ph2NH2OTf or HBArf (BArf- = {B[3,5(CF3)2C5H3]4}-) as the acid and a Co metallocene or KC8 as the reducing agent between -78 and 22 °C in diethyl ether shows that 1.20-1.34 equivalents of ammonia are formed starting with either [CAC(OMe)6]Mo(N) (50% 15N) or [CAC(OMe)3(H)3]Mo(N) (50% 15N).
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Affiliation(s)
- Lasantha A Wickramasinghe
- Department of Chemistry 6-331 , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
| | - Richard R Schrock
- Department of Chemistry 6-331 , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
| | - Charlene Tsay
- Department of Chemistry 6-331 , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
| | - Peter Müller
- Department of Chemistry 6-331 , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
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Affiliation(s)
- Hosein Tafazolian
- Department of Chemistry 6-331, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Charlene Tsay
- Department of Chemistry 6-331, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Richard R. Schrock
- Department of Chemistry 6-331, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Peter Müller
- Department of Chemistry 6-331, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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Abstract
The reaction between Mo(O)(CHAro)(ORF6)2(PMe3) (Aro = ortho-methoxyphenyl, ORF6 = OCMe(CF3)2) and 2 equiv of LiOHMT (OHMT = O-2,6-(2,4,6-Me3C6H2)2C6H3) leads to Mo(O)(CHAro)(OHMT)2, an X-ray structure of which shows it to be a trigonal bipyramidal anti benzylidene complex in which the o-methoxy oxygen is coordinated to the metal trans to the apical oxo ligand. Addition of 1 equiv of water (in THF) to the benzylidyne complex, Mo(CArp)(OR)3(THF)2 (Arp = para-methoxyphenyl, OR = ORF6 or OC(CF3)3 (ORF9)) leads to formation of {Mo(CArp)(OR)2(μ-OH)(THF)}2(μ-THF) complexes. Addition of 1 equiv of a phosphine (L) to Mo(CArp)(ORF9)3(THF)2 in THF, followed by addition of 1 equiv of water, all at room temperature, yields Mo(O)(CHArp)(ORF9)2(L) complexes in good yields for several phosphines (e.g., PMe2Ph (69% by NMR), PMePh2 (59%), PEt3 (69%), or P( i-Pr)3 (65%)). The reaction between Mo(O)(CHArp)(ORF9)2(PEt3) and 2 equiv of LiOHMT proceeds smoothly at 90 °C in toluene to give Mo(O)(CHArp)(OHMT)2, a four-coordinate syn alkylidene complex. Mo(O)(CHArp)(OHMT)2 reacts with ethylene (1 atm in C6D6) to give (in solution) a mixture of Mo(O)(CHArp)(OHMT)2, Mo(O)(CH2)(OHMT)2, and an unsubstituted square pyramidal metallacyclobutane complex, Mo(O)(CH2CH2CH2)(OHMT)2, along with ethylene and ArpCH═CH2. Mo(O)(CHArp)(OHMT)2 also reacts with 2,3-dicarbomethoxynorbornadiene to yield syn and anti isomers of the "first-insertion" products that contain a cis C═C bond.
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Affiliation(s)
- Feng Zhai
- Department of Chemistry 6-331 , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
| | - Konstantin V Bukhryakov
- Department of Chemistry 6-331 , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
| | - Richard R Schrock
- Department of Chemistry 6-331 , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
| | - Amir H Hoveyda
- Department of Chemistry, Merkert Chemistry Center , Boston College , Chestnut Hill , Massachusetts 02467 , United States
| | - Charlene Tsay
- Department of Chemistry 6-331 , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
| | - Peter Müller
- Department of Chemistry 6-331 , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
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Tsay C, Ceballos BM, Yang JY. pH-Dependent Reactivity of a Water-Soluble Nickel Complex: Hydrogen Evolution vs Selective Electrochemical Hydride Generation. Organometallics 2018. [DOI: 10.1021/acs.organomet.8b00558] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Charlene Tsay
- Department of Chemistry, University of California, Irvine, California 92697, United States
| | - Bianca M. Ceballos
- Department of Chemistry, University of California, Irvine, California 92697, United States
| | - Jenny Y. Yang
- Department of Chemistry, University of California, Irvine, California 92697, United States
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VenkatRamami S, Schrock RR, Hoveyda A, Müller P, Tsay C. Synthesis of High-Oxidation-State Mo═CHX Complexes, Where X = Cl, CF 3, Phosphonium, CN. Organometallics 2018; 37:1641-1644. [PMID: 30655653 PMCID: PMC6332497 DOI: 10.1021/acs.organomet.8b00168] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Reactions between Z-XCH=CHX where X = Cl, CF3, or CN and Mo(N-t-Bu)(CH-t-Bu)(OHIPT)Cl(PPh2Me) (OHIPT = O-2,6-(2,4,6-i-Pr3C6H2)2C6H3) produce Mo(N-t-Bu)(CHX)(OHIPT)Cl(PPh2Me) complexes. Addition of 2,2'-bipyridyl (Bipy) yields Mo(N-t-Bu)(CHX)(OHIPT)Cl(Bipy) complexes, which could be isolated and structurally characterized. The reaction between Mo(N-t-Bu)(CH-t-Bu)(OHMT)Cl(PPh2Me) (OHMT = O-2,6-(2,4,6-Me3C6H2)2C6H3) and Z-ClCH=CHCl in the presence of Bipy produces a mixture that contains both Mo(N-t-Bu)(CHCl)(OHMT)Cl(PPh2Me) and Mo(N-t-Bu)(CHCl)(OHMT)Cl(Bipy), but the relatively insoluble product that crystallizes from toluene-d 8 is the phosphoniomethylidene complex, [Mo(N-t-Bu)(CHPPh2Me)(OHMT)(Cl)(Bipy)]Cl. The Mo(N-t-Bu)(CHX)(OHIPT)Cl(PPh2Me) complexes (X = Cl or CF3) were confirmed to initiate the stereoselective cross-metathesis between Z-5-decene and Z-XCH=CHX.
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Affiliation(s)
- Sudarsan VenkatRamami
- Department of Chemistry 6-331, Massachusetts
Institute of Technology, Cambridge, Massachusetts 02139
| | - Richard R. Schrock
- Department of Chemistry 6-331, Massachusetts
Institute of Technology, Cambridge, Massachusetts 02139
| | - Amir Hoveyda
- Department of Chemistry, Merkert Chemistry Center,
Boston College, Chestnut Hill, Massachusetts 02467
| | - Peter Müller
- Department of Chemistry 6-331, Massachusetts
Institute of Technology, Cambridge, Massachusetts 02139
| | - Charlene Tsay
- Department of Chemistry 6-331, Massachusetts
Institute of Technology, Cambridge, Massachusetts 02139
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19
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Bukhryakov KV, Schrock RR, Hoveyda AH, Tsay C, Müller P. Syntheses of Molybdenum Oxo Alkylidene Complexes through Addition of Water to an Alkylidyne Complex. J Am Chem Soc 2018; 140:2797-2800. [PMID: 29432003 PMCID: PMC6293189 DOI: 10.1021/jacs.8b00499] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Addition of one equiv of water to Mo(CAr)[OCMe(CF3)2]3(1,2-dimethoxyethane) (2, Ar = o-(OMe)C6H4) in the presence of PPhMe2 leads to formation of Mo(O)(CHAr)[OCMe(CF3)2]2(PPhMe2) (3(PPhMe2)) in 34% yield. Addition of one equiv of water alone to 2 produces the dimeric alkylidyne hydroxide complex, {Mo(CAr)[OCMe(CF3)2]2(μ-OH)}2(dme) (4(dme)) in which each bridging hydroxide proton points toward an oxygen atom in an arylmethoxy group. Addition of PMe3 to 4(dme) gives the alkylidene oxo complex, (3(PMe3)), an analogue of 3(PPhMe2) (95% conversion, 66% isolated). Treatment of 3(PMe3) with two equiv of HCl gave Mo(O)(CHAr)Cl2(PMe3) (5), which upon addition of LiO-2,6-(2,4,6-i-Pr3C6H2)2C6H3 (LiOHIPT) gave Mo(O)(CHAr)(OHIPT)Cl(PMe3) (6). Compound 6 in the presence of B(C6F5)3 will initiate the ring-opening metathesis polymerization of cyclooctene, 5,6-dicarbomethoxynorbornadiene (DCMNBD), and rac-5,6-dicarbomethoxynorbornene (DCMNBE), and the homocoupling of 1-decene to 9-octadecene. The poly(DCMNBD) has a cis,syndiotactic structure, whereas poly(DCMNBE) has a cis,syndiotactic,alt structure. X-ray structures were obtained for 3(PPhMe2), 4(dme), and 6.
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Affiliation(s)
- Konstantin V Bukhryakov
- Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
| | - Richard R Schrock
- Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
| | - Amir H Hoveyda
- Department of Chemistry, Merkert Chemistry Center, Boston College , Chestnut Hill, Massachusetts 02467, United States
| | - Charlene Tsay
- Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
| | - Peter Müller
- Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
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20
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Reath AH, Ziller JW, Tsay C, Ryan AJ, Yang JY. Redox Potential and Electronic Structure Effects of Proximal Nonredox Active Cations in Cobalt Schiff Base Complexes. Inorg Chem 2017; 56:3713-3718. [DOI: 10.1021/acs.inorgchem.6b03098] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Alexander H. Reath
- Department of Chemistry, University of California, Irvine, California 92697, United States
| | - Joseph W. Ziller
- Department of Chemistry, University of California, Irvine, California 92697, United States
| | - Charlene Tsay
- Department of Chemistry, University of California, Irvine, California 92697, United States
| | - Austin J. Ryan
- Department of Chemistry, University of California, Irvine, California 92697, United States
| | - Jenny Y. Yang
- Department of Chemistry, University of California, Irvine, California 92697, United States
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21
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Bukhryakov KV, VenkatRamani S, Tsay C, Hoveyda A, Schrock RR. Syntheses of Molybdenum Adamantylimido and t-Butylimido Alkylidene Chloride Complexes Using HCI and Diphenylmethylphosphine. Organometallics 2017; 36:4208-4214. [PMID: 31659999 DOI: 10.1021/acs.organomet.7b00647] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Reactions between Mo(N-t-Bu)2(CH2-t-Bu)2 or Mo(NAdamantyl)2(CH2CMe2Ph)2 and 3 equiv of HCl in the presence of 1 equiv of PPh2Me yield Mo(NR)(CHR')(PPh2Me)Cl2 complexes, from which Mo(NR)(CHR')(PPh2Me)(OAr)Cl complexes (OAr = a 2,6-terphenoxide) can be prepared. The Mo(NR)(CHR')(PPh2Me)(OAr)Cl complexes were evaluated as cross-metathesis catalysts between cyclooctene and Z-1,2-dichloroethylene. The efficiencies of the test reaction for complexes in which OAr = OTPP, OHMT, OHIPT, or OHTBT (where OTPP is 2,3,5,6-tetraphenylphenoxide, OHMT is hexamethylterphenoxide, OHIPT is hexaisopropylterphenoxide, and OHTBT is hexa-t-butylterphenoxide) maximize when OAr is OHMT or OHIPT. Mo(N-t-Bu)(CH-t-Bu)(PPh2Me)Cl2 is essentially inactive for the reaction between cyclooctene and Z-1,2-dichloroethylene. X-ray structural studies were carried out on Mo(NAd)(CHCMe2Ph)(PPh2Me)Cl2, Mo(N-t-Bu)(CH-t-Bu)(PPh2Me)(OHMT)Cl, Mo(NAd)(CHCMe2Ph)(Cl)(OHTBT)(PMe3), and [Mo(NAd)(CHCMe2Ph)(PMe3)(Cl)]2(μ-O), the product of the reaction between Mo(NAd)(CHCMe2Ph)(Cl)(OHTBT)(PMe3) and 0.5 equiv of water.
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Affiliation(s)
- Konstantin V Bukhryakov
- Department of Chemistry 6-331, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Sudarsan VenkatRamani
- Department of Chemistry 6-331, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Charlene Tsay
- Department of Chemistry 6-331, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Amir Hoveyda
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Richard R Schrock
- Department of Chemistry 6-331, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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22
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Abstract
The hydricity (ΔGH−) of a newly synthesized nickel hydride was experimentally determined in acetonitrile (50.6 kcal mol−1), dimethyl sulfoxide (47.1 kcal mol−1), and water (22.8 kcal mol−1).
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Affiliation(s)
| | - Charlene Tsay
- Department of Chemistry
- University of California
- Irvine
- USA
| | - Jenny Y. Yang
- Department of Chemistry
- University of California
- Irvine
- USA
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23
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Tsay C, Yang JY. Electrocatalytic Hydrogen Evolution under Acidic Aqueous Conditions and Mechanistic Studies of a Highly Stable Molecular Catalyst. J Am Chem Soc 2016; 138:14174-14177. [PMID: 27416063 DOI: 10.1021/jacs.6b05851] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Electrocatalytic activity of a water-soluble nickel complex, [Ni(DHMPE)2]2+ (DHMPE = 2-bis(di(hydroxymethyl)phosphino)ethane), for the hydrogen evolution reaction (HER) at pH 1 is reported. The catalyst functions at a rate of ∼103 s-1 (kobs) with high Faradaic efficiency. Quantification of the complex before and after 18+ hours of electrolysis reveals negligible decomposition under catalytic conditions. Although highly acidic conditions are common in electrolytic cells, this is a rare example of a homogeneous catalyst for HER that functions with high stability at low pH. The stability of the compound and proposed catalytic intermediates enabled detailed mechanistic studies. The thermodynamic parameters governing electron and proton transfer were used to determine the appropriate reductants and acids to access the catalytic cycle in a stepwise fashion, permitting direct spectroscopic identification of intermediates. These studies support a mechanism for proton reduction that proceeds through two-electron reduction of the nickel(II) complex, protonation to generate [HNi(DHMPE)2]+, and further protonation to initiate hydrogen bond formation.
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Affiliation(s)
- Charlene Tsay
- Department of Chemistry, University of California , Irvine, California 92697, United States
| | - Jenny Y Yang
- Department of Chemistry, University of California , Irvine, California 92697, United States
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24
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Abstract
Illegal migration to Taiwan is a recent phenomenon but with a rapid rate of increase. Most illegal foreign workers enter on visitor's visas and overstay. This paper's detailed analysis of official data reveals that Malaysia, Philippines, Indonesia and Thailand are the major sources, providing a stock of mostly male workers numbering around 40,000. Sociodemographic and attitudinal changes among Taiwanese workers coupled with labor shortages in low-skilled jobs are pressuring the Taiwanese government to formulate plans for a systematic importation of foreign labor.
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25
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Shaffer DW, Bhowmick I, Rheingold AL, Tsay C, Livesay BN, Shores MP, Yang JY. Spin-state diversity in a series of Co(ii) PNP pincer bromide complexes. Dalton Trans 2016; 45:17910-17917. [DOI: 10.1039/c6dt03461f] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We describe the structural and electronic impacts of modifying the bridging atom in a family of Co(ii) pincer complexes with the formula Co(t-Bu)2PEPyEP(t-Bu)2Br2 (Py = pyridine, E = CH2, NH, and O for compounds 1–3, respectively).
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Affiliation(s)
| | | | | | - Charlene Tsay
- Department of Chemistry
- University of California
- Irvine
- USA
| | - Brooke N. Livesay
- Department of Chemistry
- Colorado State University
- Fort Collins
- USA
- Department of Chemistry
| | | | - Jenny Y. Yang
- Department of Chemistry
- University of California
- Irvine
- USA
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26
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Thammavongsy Z, Khosrowabadi Kotyk JF, Tsay C, Yang JY. Flexibility is Key: Synthesis of a Tripyridylamine (TPA) Congener with a Phosphorus Apical Donor and Coordination to Cobalt(II). Inorg Chem 2015; 54:11505-10. [DOI: 10.1021/acs.inorgchem.5b02133] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Zachary Thammavongsy
- Department
of Chemistry, University of California, Irvine, California 92697, United States
| | | | - Charlene Tsay
- Department
of Chemistry, University of California, Irvine, California 92697, United States
| | - Jenny Y. Yang
- Department
of Chemistry, University of California, Irvine, California 92697, United States
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27
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Affiliation(s)
- Charlene Tsay
- Department of Chemistry, University of California, Irvine, California 92697, United States
| | - Brooke N. Livesay
- Department of Chemistry, University of California, Irvine, California 92697, United States
| | - Samantha Ruelas
- Department of Chemistry, University of California, Irvine, California 92697, United States
| | - Jenny Y. Yang
- Department of Chemistry, University of California, Irvine, California 92697, United States
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28
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Affiliation(s)
- Daniel L. M. Suess
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California
91125, United States
| | - Charlene Tsay
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California
91125, United States
| | - Jonas C. Peters
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California
91125, United States
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29
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30
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Affiliation(s)
- Charlene Tsay
- California Institute of Technology, Division of Chemistry and Chemical Engineering, Pasadena, California 91125, and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Neal P. Mankad
- California Institute of Technology, Division of Chemistry and Chemical Engineering, Pasadena, California 91125, and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Jonas C. Peters
- California Institute of Technology, Division of Chemistry and Chemical Engineering, Pasadena, California 91125, and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
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31
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Dincǎ M, Dailly A, Tsay C, Long JR. Expanded Sodalite-Type Metal−Organic Frameworks: Increased Stability and H2 Adsorption through Ligand-Directed Catenation. Inorg Chem 2007; 47:11-3. [DOI: 10.1021/ic701917w] [Citation(s) in RCA: 176] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mircea Dincǎ
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, and Chemical and Environmental Sciences Laboratory, General Motors Corporation, Warren, Michigan 48090
| | - Anne Dailly
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, and Chemical and Environmental Sciences Laboratory, General Motors Corporation, Warren, Michigan 48090
| | - Charlene Tsay
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, and Chemical and Environmental Sciences Laboratory, General Motors Corporation, Warren, Michigan 48090
| | - Jeffrey R. Long
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, and Chemical and Environmental Sciences Laboratory, General Motors Corporation, Warren, Michigan 48090
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32
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Wu MF, Huang WT, Tsay C, Hsu HF, Liu BT, Chiou CM, Yen SC, Cheng SP, Ju JC. The stage-dependent inhibitory effect of porcine follicular cells on the development of preantral follicles. Anim Reprod Sci 2002; 73:73-88. [PMID: 12220820 DOI: 10.1016/s0378-4320(02)00119-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The objective of this study was to examine the effects of follicular cells on the in vitro development of porcine preantral follicles. In Experiment 1, one preantral follicle alone (Trt 1) was cocultured with a follicle of the same size with oocytes (Trt 2) or without oocytes (Trt 3). Preantral follicles cultured alone in vitro for 12 days had greater follicle diameters (1017 +/- 96 microm versus 706 +/- 69 or 793 +/- 72 microm, P < 0.05), growth rates (201 +/- 0.3 versus 103 +/- 0.2 or 128 +/- 0.2, P < 0.05) and oocyte survival rates (73% versus 48, or 25%, P < 0.05) than other groups. The inhibitory effects of follicle cells on the growth of preantral follicles and oocyte survival rates were not enhanced by the addition of oocytectomized preantral follicles (Experiment 2). Follicles were cocultured with different sources of follicular cells in other experiments. Coculture with cumulus cells enhanced oocyte survival compared to the control (without coculture) and mural follicular cell groups (Experiment 3). The growth and survival rates of oocytes collected from the group of follicles cocultured with cumulus cells from large antral follicles (>3 mm) were greater (P < 0.05) than those from small antral follicles (<3 mm), or than the control group (without cumulus cells, experiment 4). No significant differences in the follicular diameters (674 +/- 30 microm versus 638 +/- 33 and 655 +/- 28 microm) and growth rate (105% versus 94 and 105%) were observed among the preantral follicles of the different treatments (P > 0.05). Taken together, coculture with the cells from large antral follicles (>3 mm) exerted a significant positive effect on oocyte survival. The growth and oocyte survival of preantral follicle cocultured with the same size of follicles (with or without oocyte) were inhibited. Growth and survival rates of preantral follicles and oocytes are improved by coculturing them with the cumulus cells derived from larger antral follicles.
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Affiliation(s)
- M F Wu
- Graduate Institute of Animal Science, National Chung-Hsing University, Taichung 402, Taiwan, ROC
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33
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Ju JC, Chen TH, Tseng JK, Tsay C, Yeh SP, Chou PC, Chen CH, Liu CT. Cytoskeletal Patterns, In Vitro Maturation and Parthenogenetic Development of Rabbit GV Oocytes. Asian Australas J Anim Sci 2002. [DOI: 10.5713/ajas.2002.1695] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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34
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Lin J, Liaw K, Tsay C. Determinants of fast repeat migrations of the labor force: evidence from the linked national survey data of Taiwan. Environ Plan A 1999; 31:925-945. [PMID: 12322173 DOI: 10.1068/a310925] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
"The main objectives of this paper are (1) to identify the determinants of job-related fast repeat migrations of individuals in the civilian labor force of Taiwan, and (2) to examine whether the effects of these determinants are largely consistent with the existing theories and with the findings of other empirical studies. Our study is based on the linked microdata of the annual national migration surveys of Taiwan from 1980 through 1989.... We review the main theories of repeat migrations and formulate a set of hypotheses that can be tested against the Taiwanese data."
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35
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Miller CW, Aslo A, Tsay C, Slamon D, Ishizaki K, Toguchida J, Yamamuro T, Lampkin B, Koeffler HP. Frequency and structure of p53 rearrangements in human osteosarcoma. Cancer Res 1990; 50:7950-4. [PMID: 2253237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Osteosarcoma is the most frequent childhood bone cancer (Tebbi, C. K., and Gaeta, J. Pediatr. Ann., 17:285-300, 1988). Using Southern blot mapping, we found that 11 of 60 (18%) osteosarcomas had altered restriction patterns of the p53 gene and that six of these had loss of the other p53 allele. In contrast, no alteration of the p53 gene was detected in 50 samples from other types of sarcomas. Fifty % of osteosarcoma cell lines (4 of 8) also had gross rearrangements of one p53 allele with loss of the second allele, and these had no detectable p53 mRNA. Osteosarcoma cell lines with no detectable alteration of the p53 gene contained abundant p53 transcripts. Taken together, data show that human osteosarcomas can have rearrangements of the p53 gene; these rearrangements may cause loss of normal constraints on cellular growth.
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Affiliation(s)
- C W Miller
- Division of Hematology/Oncology, Cedars-Sinai Medical Center, Los Angeles, California
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36
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Tsay C. Possible effects of transportation on mortality differentials in central Taiwan. Jing Ji Lun Wen 1985; 13:145-66. [PMID: 12178379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
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37
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Tsay C. [Trends of phase-specific life expectancy in postwar Taiwan]. Jing Ji Lun Wen 1983; 11:31-59. [PMID: 12178384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
Abstract
The decline in mortality in Taiwan since World War II is analyzed using life tables. "Special features of the research include (1) a phase-of-life-specific, rather than an age-specific, analysis of mortality, and (2) the use of measures based upon person-years of life in phase intervals, rather than survival rates or expectation of life at given ages. The empirical results suggest that the mortality decline can be described as a two-stage process: an initial stage of substantial improvement in life expectancy between 1950 and 1965, and a final stage of slow gain in life expectancy since 1965." Age and sex variations in mortality and differing rates of mortality decline are noted. Implications of increased longevity for economic and social programs are also considered. (summary in ENG)
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