1
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Abstract
Ruthenium-based olefin metathesis catalysts, known for their functional group tolerance and broad applicability in organic synthesis and polymer science, continue to evolve as an enabling technology in these areas. A discussion of recent mechanistic investigations is followed by an overview of selected applications.
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Affiliation(s)
- O M Ogba
- Department of Chemistry, Pomona College, 645 North College Avenue, Claremont, California 91775, USA.
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2
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Rosebrugh LE, Ahmed TS, Marx VM, Hartung J, Liu P, López JG, Houk KN, Grubbs RH. Probing Stereoselectivity in Ring-Opening Metathesis Polymerization Mediated by Cyclometalated Ruthenium-Based Catalysts: A Combined Experimental and Computational Study. J Am Chem Soc 2016; 138:1394-405. [PMID: 26726835 DOI: 10.1021/jacs.5b12277] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The microstructures of polymers produced by ring-opening metathesis polymerization (ROMP) with cyclometalated Ru-carbene metathesis catalysts were investigated. A strong bias for a cis,syndiotactic microstructure with minimal head-to-tail bias was observed. In instances where trans errors were introduced, it was determined that these regions were also syndiotactic. Furthermore, hypothetical reaction intermediates and transition structures were analyzed computationally. Combined experimental and computational data support a reaction mechanism in which cis,syndio-selectivity is a result of stereogenic metal control, while microstructural errors are predominantly due to alkylidene isomerization via rotation about the Ru═C double bond.
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Affiliation(s)
- L E Rosebrugh
- Arnold and Mabel Beckman Laboratory of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology , Pasadena, California 91125, United States
| | - T S Ahmed
- Arnold and Mabel Beckman Laboratory of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology , Pasadena, California 91125, United States
| | - V M Marx
- Arnold and Mabel Beckman Laboratory of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology , Pasadena, California 91125, United States
| | - J Hartung
- Arnold and Mabel Beckman Laboratory of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology , Pasadena, California 91125, United States
| | - P Liu
- Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States
| | - J G López
- Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States
| | - K N Houk
- Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States
| | - R H Grubbs
- Arnold and Mabel Beckman Laboratory of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology , Pasadena, California 91125, United States
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3
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Aluculesei A, Pipertzis A, Piunova VA, Miyake GM, Floudas G, Fytas G, Grubbs RH. Thermomechanical Behavior and Local Dynamics of Dendronized Block Copolymers and Constituent Homopolymers. Macromolecules 2015. [DOI: 10.1021/acs.macromol.5b00779] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- A. Aluculesei
- Department
of Materials Science, FORTH-IESL, P.O. Box 1527, 71110 Heraklion, Greece
| | - A. Pipertzis
- Department
of Physics, University of Ioannina, 45110 Ioannina, Greece
| | - V. A. Piunova
- Arnold
and Mabel Beckmam Laboratories for Chemical Synthesis, Division of
Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - G. M. Miyake
- Arnold
and Mabel Beckmam Laboratories for Chemical Synthesis, Division of
Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - G. Floudas
- Department
of Physics, University of Ioannina, 45110 Ioannina, Greece
| | - G. Fytas
- Department
of Materials Science, FORTH-IESL, P.O. Box 1527, 71110 Heraklion, Greece
- Max Planck Institute
for Polymer Research, D-55128 Mainz, Germany
| | - R. H. Grubbs
- Arnold
and Mabel Beckmam Laboratories for Chemical Synthesis, Division of
Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
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4
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Dong G, Teo P, Wickens ZK, Grubbs RH. Primary Alcohols from Terminal Olefins: Formal Anti-Markovnikov Hydration via Triple Relay Catalysis. Science 2011; 333:1609-12. [DOI: 10.1126/science.1208685] [Citation(s) in RCA: 175] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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5
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Marder SR, Perry JW, Schaefer WP, Ginsburg EJ, Gorman CB, Grubbs RH. Organic, Organometallic and Polymeric Materials with Nonlinear Optical Properties. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-175-101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractNew approaches to both second-order and third-order nonlinear optical materials are presented. A series of organometallic and organic salts, in which the cation has been designed to have a large molecular hyperpolarizability, has been prepared and the SHG efficiencies were measured. Partially substituted derivatives of polyacetylene are synthesized via the ring-opening metathesis polymerization (ROMP) of cyclooctatetraene (COT) and its derivatives. Certain poly-COT derivatives afford soluble, highly conjugated polyacetylenes. These materials exhibit large third-order optical nonlinearities and low scattering losses.
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6
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Gajda GJ, Grubbs RH, Weinberg WH. An inelastic electron tunneling spectroscopic investigation of the interaction of molybdenum hexacarbonyl with an aluminum oxide surface. J Am Chem Soc 2002. [DOI: 10.1021/ja00235a011] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Schrock RR, Feldman J, Cannizzo LF, Grubbs RH. Ring-opening polymerization of norbornene by a living tungsten alkylidene complex. Macromolecules 2002. [DOI: 10.1021/ma00171a053] [Citation(s) in RCA: 186] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Pine SH, Zahler R, Evans DA, Grubbs RH. Titanium-mediated methylene-transfer reactions. Direct conversion of esters into vinyl ethers. J Am Chem Soc 2002. [DOI: 10.1021/ja00529a076] [Citation(s) in RCA: 234] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Ho SCH, Straus DA, Armantrout J, Schaefer WP, Grubbs RH. Structure and reactivity of the zirconaenolate anion [Cp2Zr(C,O-.eta.2-OCCH2)CH3]Na.2THF. Synthesis of homo- and heterobinuclear ketene complexes. J Am Chem Soc 2002. [DOI: 10.1021/ja00319a051] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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14
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Bonds WD, Brubaker CH, Chandrasekaran ES, Gibbons C, Grubbs RH, Kroll LC. Polystyrene attached titanocene species. Preparation and reactions. J Am Chem Soc 2002. [DOI: 10.1021/ja00841a022] [Citation(s) in RCA: 124] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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15
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Louie J, Bielawski CW, Grubbs RH. Tandem catalysis: the sequential mediation of olefin metathesis, hydrogenation, and hydrogen transfer with single-component Ru complexes. J Am Chem Soc 2001; 123:11312-3. [PMID: 11697983 DOI: 10.1021/ja016431e] [Citation(s) in RCA: 372] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- J Louie
- Arnold and Mabel Beckman Laboratories of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
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16
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Affiliation(s)
- T L Choi
- Arnold and Mabel Beckman Laboratories of Chemical Synthesis Division of Chemistry and Chemical Engineering California Institute of Technology Pasadena, California 91125, USA
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17
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Abstract
The enhanced metathesis activity of 1,3-dimesityl-4,5-dihydroimidazole-2-ylidene ruthenium carbene catalyst 3 significantly increases the feasibility of synthesizing macrocyclic compounds. Catalyst 3 exhibits sufficient activity in RCM to dimerize alpha,beta-unsaturated ester substrates and afford the corresponding head-to-tail (E,E)-dimeric (and trimeric) macrocycles. The dimerization appears to be under thermodynamic control with the product mixture dependent not only on the electronic and steric nature of the substrate but also on concentration.
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Affiliation(s)
- C W Lee
- Arnold and Mabel Beckman Laboratories of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
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18
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Abstract
[reaction: see text] The first enantioselective ruthenium olefin metathesis catalysts have been prepared, and high enantiomeric excesses (up to 90%) are observed in the desymmetrization of achiral trienes. A model consistent with the stereochemical outcome of the reactions is described and suggests side-on olefin binding and reorganization of the halide ligands.
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Affiliation(s)
- T J Seiders
- Arnold and Mabel Beckman Laboratory of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
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19
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Blackwell HE, Sadowsky JD, Howard RJ, Sampson JN, Chao JA, Steinmetz WE, O'Leary DJ, Grubbs RH. Ring-closing metathesis of olefinic peptides: design, synthesis, and structural characterization of macrocyclic helical peptides. J Org Chem 2001; 66:5291-302. [PMID: 11485448 DOI: 10.1021/jo015533k] [Citation(s) in RCA: 194] [Impact Index Per Article: 8.4] [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: 11/30/2022]
Abstract
Heptapeptides containing residues with terminal olefin-derivatized side chains (3 and 4) have been treated with ruthenium alkylidene 1 and undergone facile ring-closing olefin metathesis (RCM) to give 21- and 23-membered macrocyclic peptides (5 and 6). The primary structures of peptides 3 and 4 were based upon a previously studied heptapeptide (2), which was shown to adopt a predominantly 3(10)-helical conformation in CDCl(3) solution and an alpha-helical conformation in the solid state. Circular dichroism, IR, and solution-phase (1)H NMR studies strongly suggested that acyclic precursors 3 and 4 and the fully saturated macrocyclic products 7 and 8 also adopted helical conformations in apolar organic solvents. Single-crystal X-ray diffraction of cyclic peptide 8 showed it to exist as a right-handed 3(10)-helix up to the fifth residue. Solution-phase NMR structures of both acyclic peptide 4 and cyclic peptide 8 in CD(2)Cl(2) indicated that the acyclic diene assumes a loosely 3(10)-helical conformation, which is considerably rigidified upon macrocyclization. The relative ease of introducing carbon-carbon bonds into peptide secondary structures by RCM and the predicted metabolic stability of these bonds renders olefin metathesis an exceptional methodology for the synthesis of rigidified peptide architectures.
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Affiliation(s)
- H E Blackwell
- The Arnold and Mabel Beckman Laboratory of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
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20
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Abstract
This report details the effects of ligand variation on the mechanism and activity of ruthenium-based olefin metathesis catalysts. A series of ruthenium complexes of the general formula L(PR(3))(X)(2)Ru=CHR(1) have been prepared, and the influence of the substituents L, X, R, and R(1) on the rates of phosphine dissociation and initiation as well as overall activity for olefin metathesis reactions was examined. In all cases, initiation proceeds by dissociative substitution of a phosphine ligand (PR(3)) with an olefinic substrate. All of the ligands L, X, R, and R(1) have a significant impact on initiation rates and on catalyst activity. The origins of the observed substituent effects as well as the implications of these studies for the design and implementation of new olefin metathesis catalysts and substrates are discussed in detail.
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Affiliation(s)
- M S Sanford
- Arnold and Mabel Beckman Laboratories for Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
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21
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Schwartz DM, Jethmalani JM, Sandstedt CA, Kornfield JA, Grubbs RH. Post implantation adjustable intraocular lenses. Ophthalmol Clin North Am 2001; 14:339-45, viii. [PMID: 11406429] [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] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
To eliminate persistent refractive errors after cataract and phakic IOL surgery, photosensitive silicone IOLs have been developed. These IOL formulations enable precise laser adjustment of IOL power to correct spherical and toric errors post-operatively, after wound and IOL stabilization. Initial experience with these laser adjustable IOLs indicate excellent biocompatability and adjustability of more than five diopters.
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Affiliation(s)
- D M Schwartz
- Department of Ophthalmology, University of California San Francisco, San Francisco, California, USA.
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22
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Abstract
A novel organometallic transformation is reported in which the alkylidene protons of water-soluble ruthenium alkylidenes 1 and 2 undergo nondestructive, degenerate exchange with solvent-derived deuterons in perdeuterated protic solvents such as D(2)O and CD(3)OD. Deuterated alkylidene complex (1-D) was isolated from a solution of alkylidene 1 in D(2)O, and the new alkylidene was fully characterized by (1)H, (2)H, (13)C, and (31)P NMR spectroscopy and fast-atom bombardment mass spectroscopy (FAB-MS). The rate of alkylidene proton exchange for this transformation was found to correlate with the bulk dielectric constant of the solvent or solvent mixtures employed. The data support a mechanism for proton exchange involving the dissociation of a chloride ion from the ruthenium metal center. The rate of alkylidene H/D exchange for alkylidene 2 was faster than the rate of exchange for alkylidene 1, demonstrating that relative rates of exchange are influenced by the electron densities at the metal centers of these complexes. Several additional ruthenium alkylidenes were found to undergo analogous alkylidene H/D exchange reactions, including parent alkylidene (Cy(3)P)(2)Cl(2)Ru=CHPh (3) in CD(2)Cl(2)/CD(3)OD mixtures. These data suggest that this novel reactivity may be general for an entire class of ruthenium alkylidenes provided that protic species are available in solution and that the dielectric constant of the reaction medium is sufficiently high to ionize the halide ligands.
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Affiliation(s)
- D M Lynn
- Arnold and Mabel Beckman Laboratories of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
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23
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Abstract
Polynorbornenes substituted with two different peptide sequences from the RGD-containing integrin cell-binding domain of fibronectin are potent inhibitors of human foreskin fibroblast cell adhesion to fibronectin-coated surfaces. Ring-opening metathesis polymerization (ROMP) using Ru==CHPh(Cl)(2)(PCy(3))(DHIMes) (1) as an initiator produced polymers substituted with GRGDS and PHSRN peptide sequences. The inhibitory activity was quantified for these polymers and compared to the free peptides and GRGES-containing controls. A homopolymer substituted with GRGDS peptides was significantly more active than the free GRGDS peptide (IC(50) of 0.18 +/- 0.03 and 1.33 +/- 0.20 mM respectively), and the copolymer containing both GRGDS and PHSRN is the most potent inhibitor (IC(50) of 0.04 +/- 0.01 mM). These results demonstrate that significant enhancements of observed biological activity can be obtained from polymeric materials containing more than one type of multivalent ligand and that ROMP is a useful method to synthesize such well-defined copolymers.
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Affiliation(s)
- H D Maynard
- Arnold and Mabel Beckman Laboratories of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
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24
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Affiliation(s)
- M S Sanford
- Arnold and Mabel Beckman Laboratories of Chemical Synthesis, California Institute of Technology Pasadena, California 91125, USA
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25
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Abstract
In recent years, the olefin metathesis reaction has attracted widespread attention as a versatile carbon-carbon bond-forming method. Many new applications have become possible because of major advances in catalyst design. State-of-the-art ruthenium catalysts are not only highly active but also compatible with most functional groups and easy to use. This Account traces the ideas and discoveries that were instrumental in the development of these catalysts, with particular emphasis on (PCy3)2Cl2Ru=CHPh and its derivatives. The discussion includes an analysis of trends in catalyst activity, a description of catalysts coordinated with N-heterocyclic carbene ligands, and an overview of ongoing work to improve the activity, stability, and selectivity of this family of L2X2Ru=CHR complexes.
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Affiliation(s)
- T M Trnka
- Arnold and Mabel Beckman Laboratory of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
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26
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Abstract
Highly active N-heterocyclic carbene-coordinated catalysts may be synthesized and used in situ, without requiring prior isolation of the catalyst. Activation of this in situ catalyst with ethereal HCl dramatically reduces the reaction times required for high conversions. A variety of alpha,beta-unsaturated carbonyl-containing substrates participate readily in cross and ring-closing metathesis reactions using this preparation.
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Affiliation(s)
- J P Morgan
- The Arnold and Mabel Beckman Laboratories for Chemical Synthesis, California Institute of Technology, Pasadena, California 91125, USA
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27
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Sanford MS, Henling LM, Day MW, Grubbs RH. Ruthenium-Based Four-Coordinate Olefin Metathesis Catalysts The authors thank the NSF for generous support of this research. Angew Chem Int Ed Engl 2000; 39:3451-3453. [PMID: 11091386 DOI: 10.1002/1521-3773(20001002)39:19<3451::aid-anie3451>3.0.co;2-u] [Citation(s) in RCA: 132] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- MS Sanford
- Arnold and Mabel Laboratories of Chemical Synthesis California Institute of Technology Division of Chemistry and Chemical Engineering Mail Code 164-30, Pasadena, CA 91125 (USA)
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28
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Abstract
We describe here a new compound, B-NOD, which, in vitro and in situ, releases nitric oxide (NO). Its activity in situ persists for more than 7 h, it does not cause a fall in blood pressure or an increase in heart rate and can be orally administered. It increases cyclic guanosine monophosphate (cGMP) and prevents platelet aggregation. In vitro, its release of NO is augmented by the presence of living cells (blood platelets). B-NOD may be useful in a number of clinical conditions in which prolonged release of NO without hemodynamic effects are desirable. A combination of aspirin with B-NOD could be formulated in which the individual concentrations of aspirin and B-NOD may be useful in the long-term treatment of coronary artery disease and in clinical situations in which long-term release of NO may be beneficial.
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Affiliation(s)
- R J Bing
- Department of Experimental Cardiology, Huntington Medical Research Institutes, 99 North El Molino Avenue, Pasadena, California 91101, USA.
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Bielawski CW, Grubbs RH. Highly Efficient Ring-Opening Metathesis Polymerization (ROMP) Using New Ruthenium Catalysts Containing N-Heterocyclic Carbene Ligands C.B. is grateful to the National Science Foundation for a pre-doctoral fellowship. The authors thank Dr. Matthias Scholl for providing catalysts 4 a and 4 c. Angew Chem Int Ed Engl 2000; 39:2903-2906. [PMID: 11028004 DOI: 10.1002/1521-3773(20000818)39:16<2903::aid-anie2903>3.0.co;2-q] [Citation(s) in RCA: 488] [Impact Index Per Article: 20.3] [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)
- CW Bielawski
- Division of Chemistry and Chemical Engineering California Institute of Technology Pasadena, CA 91125 (USA)
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30
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Abstract
[reaction: see text] Macrocyclic ring-closing olefin metathesis using ruthenium catalyst 3 was performed to produce a 14-membered lactone. The E/Z ratio of lactone was high regardless of the R group (auxiliary) or the initial alkene stereochemistry. A kinetic study demonstrates that the high E/Z ratio is due to secondary metathesis reactions that isomerize the product to the thermodynamic E/Z ratio.
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Affiliation(s)
- C W Lee
- The Arnold and Mabel Beckman Laboratory of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
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Matzger AJ, Lawrence CE, Grubbs RH, Lewis NS. Combinatorial approaches to the synthesis of vapor detector arrays for use in an electronic nose. J Comb Chem 2000; 2:301-4. [PMID: 10891095 DOI: 10.1021/cc990056t] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- A J Matzger
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
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Ostoja Starzewski KA, Younkin TR, Connor EF, Henderson JI, Friedrich SK, Grubbs RH, Bansleben DA. Scope of Olefin Polymerization Nickel Catalysts. Science 2000; 288:1749-51. [PMID: 17836688 DOI: 10.1126/science.288.5472.1749] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Younkin TR, Connor EF, Henderson JI, Friedrich SK, Grubbs RH, Bansleben DA. Neutral, single-component nickel (II) polyolefin catalysts that tolerate heteroatoms. Science 2000; 287:460-2. [PMID: 10642541 DOI: 10.1126/science.287.5452.460] [Citation(s) in RCA: 878] [Impact Index Per Article: 36.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
More than half of the 170 million metric tons of polymers produced each year are polyolefins. Current technology uses highly active cationic catalysts, which suffer from an inability to tolerate heteroatoms such as oxygen, nitrogen, and sulfur. These systems require scrupulously clean starting materials and activating cocatalysts. A family of catalysts has been developed whose members are tolerant of both heteroatoms and less pure starting materials. These heteroatom-tolerant neutral late transition metal complexes are in fact highly active systems that produce high-molecular-weight polyethylene, polymerize functionalized olefins, and require no cocatalyst.
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Affiliation(s)
- TR Younkin
- Arnold and Mabel Beckman Laboratories for Chemical Synthesis, California Institute of Technology, Pasadena, CA 91125, USA
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34
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Abstract
[formula: see text] Trisubstituted alkenes have been prepared for the first time via intermolecular olefin cross-metathesis, using 1,3-dimesityl-4,5-dihydroimidazol-2-ylidene ruthenium alkylidene complexes 3a,b in good yields with moderate E selectivity. In addition, protected alcohols near the geminal disubstituted olefin improve reactivity for cross-metathesis.
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Affiliation(s)
- A K Chatterjee
- Arnold and Mabel Beckman Laboratory of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena 91125, USA
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35
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Scholl M, Ding S, Lee CW, Grubbs RH. Synthesis and activity of a new generation of ruthenium-based olefin metathesis catalysts coordinated with 1,3-dimesityl-4,5-dihydroimidazol-2-ylidene ligands. Org Lett 1999; 1:953-6. [PMID: 10823227 DOI: 10.1021/ol990909q] [Citation(s) in RCA: 2829] [Impact Index Per Article: 113.2] [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: 11/30/2022]
Abstract
[formula: see text] A new family of 1,3-dimesityl-4,5-dihydroimidazol-2-ylidene-substituted ruthenium-based complexes 9a-c has been prepared starting from RuCl2(=CHPh)(PCy3)2 2. These air- and water-tolerant complexes were shown to exhibit an increased ring-closing metathesis activity at elevated temperature when compared to that of the parent complex 2 and the previously developed complex 3. In many instances the activity of these complexes also rivaled or exceeded that of the alkoxy-imido molybdenum complex 1. Catalyst loadings of as low as 0.05 mol% could be used.
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Affiliation(s)
- M Scholl
- Arnold and Mabel Beckman Laboratory of Chemical Synthesis, California Institute of Technology, Pasadena 91125, USA
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36
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Weck M, Dunn AR, Matsumoto K, Coates GW, Lobkovsky EB, Grubbs RH. Influence of Perfluoroarene-Arene Interactions on the Phase Behavior of Liquid Crystalline and Polymeric Materials. Angew Chem Int Ed Engl 1999; 38:2741-2745. [PMID: 10508367 DOI: 10.1002/(sici)1521-3773(19990917)38:18<2741::aid-anie2741>3.0.co;2-1] [Citation(s) in RCA: 192] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A stabilization of the liquid-crystalline mesophase and thus an enlarged temperature range of the mesogenic phase is achieved by adding perfluorotriphenylene to a chiral liquid-crystalline triphenylene. This mesophase is based on 1:1 perfluoroarene-arene interactions (see picture). In a polymer with triphenylenes as mesogens in the side chains, the addition of perfluorotriphenylene led to crystallization.
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Affiliation(s)
- M Weck
- Arnold and Mabel Beckman Laboratories of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125 (USA)
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Doleman BJ, Sanner RD, Severin EJ, Grubbs RH, Lewis NS. Use of compatible polymer blends to fabricate arrays of carbon black-polymer composite vapor detectors. Anal Chem 1998; 70:2560-4. [PMID: 9666726 DOI: 10.1021/ac971238h] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.4] [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: 02/08/2023]
Abstract
Compatible blends of poly(vinyl acetate) and poly(methyl methacrylate) have been used to produce a series of electrically conducting carbon black composites whose resistance is sensitive to the nature and concentration of an analyte in the vapor phase. The dc electrical resistance response of the composites was found to be a nonlinear function of the mole fraction of poly(vinyl acetate) in the blend. These compatible blend composite detectors provided additional analyte discrimination information relative to a reference detector array that only contained composites formed using the pure polymer phases. The added discrimination power provided by the compatible blend detectors, and thus the added diversity of the enhanced detector array, was quantified through use of a statistical metric to assess the performance of detector arrays in various vapor classification tasks.
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Affiliation(s)
- B J Doleman
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena 91125, USA
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Fujiwara M, Grubbs RH, Baldeschwieler JD. Characterization of pH-Dependent Poly(acrylic Acid) Complexation with Phospholipid Vesicles. J Colloid Interface Sci 1997; 185:210-6. [PMID: 9056334 DOI: 10.1006/jcis.1996.4608] [Citation(s) in RCA: 58] [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: 02/03/2023]
Abstract
The pH-dependent complexation of poly(acrylic acid) (PAA) with phospholipid (phosphatidylcholine) vesicles was characterized by fluorescence polarization, differential scanning calorimetry (DSC), and surface pressure measurements of phospholipid monolayers. The complexation was pronounced below pH 4, when the polymer carboxyl groups are protonated, as shown by the binding of PAA to vesicles and the decrease in polymer mobility. The complexation was strong at low polymer concentrations and was weaker at higher polymer concentrations. PAA complexation increased the gel to liquid crystalline (LC) phase transition temperature (Tm) and enthalpy (DeltaH) of the vesicles accompanied by a decrease in the transition cooperativity. This is most likely due to perturbations in the phospholipid headgroup upon PAA interaction. The effect of polymer adsorption on the phospholipid surface was investigated at the phospholipid/water interface. The ability of PAA to penetrate between the phospholipid molecules as a function of pH was determined by the lateral expansion of the monolayer at a constant surface pressure. The ability of the polymer to penetrate into the monolayer increased with decreasing pH. These results suggest that PAA complexation leads to expansion of the phospholipid packing of the vesicles by altering the phospholipid headgroup conformation.
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Affiliation(s)
- M Fujiwara
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, 91125
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Day MW, Mohr B, Grubbs RH. (Dicyclohexylphosphino)borane, BH3PH(C6H11)2, a Precursor to Water-Soluble Phosphine Ligands. Acta Crystallogr C 1996. [DOI: 10.1107/s0108270196010050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Day MW, Wilhelm TE, Grubbs RH. A Diphenylcyclopropene Complex of Tungsten, [WCl2O(PMePh2)2(η2-3,3-diphenylcyclopropene)], Precursor to a Tungsten–Oxo–Olefin Metathesis Catalyst. Acta Crystallogr C 1996. [DOI: 10.1107/s0108270196006464] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Fujiwara M, Baldeschwieler JD, Grubbs RH. Receptor-mediated endocytosis of poly(acrylic acid)-conjugated liposomes by macrophages. Biochim Biophys Acta 1996; 1278:59-67. [PMID: 8611608 DOI: 10.1016/0005-2736(95)00183-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The uptake characteristics of negatively-charged liposomes made by conjugation of poly(acrylic acid) (PAA) were studied with respect to cultured RAW macrophages. The PAA-conjugated liposomes were internalized and digested in an acidic compartment at a much faster rate than the unmodified phosphatidylcholine (PC) liposomes. After incubation for 18 h, an over 5-fold increase in the uptake of PC liposomes was obtained by PAA conjugation. Subsequently, part of the aqueous phase of the internalized liposomes was exocytosed. Recognition of PAA by the macrophages seems to be responsible for the enhanced uptake of PAA-conjugated liposomes. Cross-competition experiments showed that PAA-conjugated liposomes inhibited the uptake of acetylated-low density lipoprotein (acetyl-LDL) by the macrophages and vice versa. The uptake of PAA-conjugated liposomes was also inhibited by dextran sulfate and maleylated-bovine serum albumin (maleyl-BSA), which are also known to bind to scavenger receptors. Poly(C) and BSA, which are not ligands for the scavenger receptor, competed poorly with the uptake of PAA-conjugated liposomes. Enhanced uptake of PAA-conjugated liposomes by CHO cells with low scavenger receptor expression was not observed. Unexpectedly, LDL, which is not a ligand for scavenger receptor, also partially inhibited the uptake of PAA-conjugated liposomes. The interaction of PAA-conjugated liposomes with macrophages is complex, and the endocytosis of PAA-conjugated liposomes most likely involves multiple receptors and/or pathways. The data obtained suggest that the high affinity binding of PAA-conjugated liposomes to macrophages may be due to recognition of the negative charges of PAA by cell surface receptors, including the scavenger receptor.
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Affiliation(s)
- M Fujiwara
- Division of Chemistry and Chemical Engineering, California Institute of Technology (Caltech 127-72), Pasadena 91125, USA
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Sailor MJ, Ginsburg EJ, Gorman CB, Kumar A, Grubbs RH, Lewis NS. Thin Films of
n
-Si/Poly-(CH
3
)
3
Si-Cyclooctatetraene: Conducting-Polymer Solar Cells and Layered Structures. Science 1990; 249:1146-9. [PMID: 17831984 DOI: 10.1126/science.249.4973.1146] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The optical and electronic properties of thin films of the solution-processible polymer poly-(CH(3))(3)Si-cyclooctatetraene are presented. This conjugated polymer is based on a polyacetylene backbone with (CH(3))(3)Si side groups. Thin transparent films have been cast onto n-doped silicon (n-Si) substrates and doped with iodine to form surfacebarrier solar cells. The devices produce photovoltages that are at the theoretical limit and that are much greater than can be obtained from n-Si contacts with conventional metals. Two methods for forming layered polymeric materials, one involving the spincoating of preformed polymers and the other comprising the sequential polymerization of different monomers, are also described. An organic polymer analog of a metal/insulator/metal capacitor has been constructed with the latter method.
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Abstract
Mechanistic and synthetic studies in organometallic chemistry have provided considerable insight into olefin metathesis and Ziegler-Natta polymerization. New homogeneous olefin metathesis catalysts based on high oxidation state transition metals have opened new opportunities in polymer synthesis by providing unprecedented control in ring-opening polymerization of cyclic alkenes. The recent development of living coordinative polymerization systems has led to the preparation of a number of new, interesting materials, including block copolymers, conducting polymers or precursors, and ionophoric polymeric substrates.
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Affiliation(s)
- R H Grubbs
- California Institute of Technology, Pasadena 91125
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Gajda GJ, Grubbs RH, Weinberg WH. An inelastic electron-tunneling spectroscopic investigation of the reaction of molybdenum oxychlorides with a hydroxylated aluminum oxide surface. J Am Chem Soc 1987. [DOI: 10.1021/ja00253a011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Grubbs RH, Kroll LC, Sweet EM. Die Darstellung und Selektivit�t eines Olefinhydrierungskatalysators, der Rh(I) an Polymeres gebunden enth�lt. Colloid Polym Sci 1975. [DOI: 10.1007/bf01470282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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