1
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Probst P, Groos J, Wang D, Beck A, Gugeler K, Kästner J, Frey W, Buchmeiser MR. Stereoselective Ring Expansion Metathesis Polymerization with Cationic Molybdenum Alkylidyne N-Heterocyclic Carbene Complexes. J Am Chem Soc 2024; 146:8435-8446. [PMID: 38482664 DOI: 10.1021/jacs.3c14457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/28/2024]
Abstract
Molybdenum alkylidyne N-heterocyclic carbene (NHC) complexes of the type [Mo(C-p-C6H4Y)(OC(R)(CF3)2)2 (L)(NHC)][B(ArF)4] (Y = OMe, NO2; R = CH3, CF3; L = none, pivalonitrile, tetrahydrofuran; NHC = 1,3-dimesitylimidazol-2-ylidene (IMes), 1,3-dimesityl-3,4-dihydroimidazol-2-ylidene (IMesH2), 1,3-dimesityl-3,4-dichloroimidazol-2-ylidene (IMesCl2), 1,3-diisopropylimidazol-2-ylidene (IiPr); B(ArF)4- = tetrakis(3,5-bis(trifluoromethyl)phen-1-yl)borate) were used in the ring expansion metathesis polymerization (REMP) of cyclic olefins. With cis-cyclooctene (cCOE) cyclic, low molecular weight oligomers were obtained at low monomer concentrations and the cyclic nature of the polymer was confirmed by MALDI-TOF measurements. High-molecular weight cyclic poly(cCOE) became available at high monomer concentrations. Also, post-REMP allowed for converting low-molecular-weight cyclic poly(cCOE) into high-molecular-weight cyclic poly(cCOE). Tailored catalysts together with suitable additives offered access to the stereoselective REMP of functional norbornenes providing functional cis-isotactic (cis-it), cis-syndiotactic (cis-st) and trans-it poly(norbornene)s with up to 99% stereoselectivity. Mechanistic details supported by density functional theory (DFT) calculations are outlined.
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Affiliation(s)
- Patrick Probst
- Institute of Polymer Chemistry, Pfaffenwaldring 55, D-70569 Stuttgart, Germany
| | - Jonas Groos
- Institute of Polymer Chemistry, Pfaffenwaldring 55, D-70569 Stuttgart, Germany
| | - Dongren Wang
- Institute of Polymer Chemistry, Pfaffenwaldring 55, D-70569 Stuttgart, Germany
| | - Alexander Beck
- Institute for Theoretical Chemistry, Pfaffenwaldring 55, D-70569 Stuttgart, Germany
| | - Katrin Gugeler
- Institute for Theoretical Chemistry, Pfaffenwaldring 55, D-70569 Stuttgart, Germany
| | - Johannes Kästner
- Institute for Theoretical Chemistry, Pfaffenwaldring 55, D-70569 Stuttgart, Germany
| | - Wolfgang Frey
- Institute of Organic Chemistry, Pfaffenwaldring 55, D-70569 Stuttgart, Germany
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2
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Kly S, Huang Y, Moffitt MG. Enhancement of cellular uptake by increasing the number of encapsulated gold nanoparticles in polymeric micelles. J Colloid Interface Sci 2023; 652:142-154. [PMID: 37591076 DOI: 10.1016/j.jcis.2023.08.060] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 08/07/2023] [Accepted: 08/09/2023] [Indexed: 08/19/2023]
Abstract
We apply a combination of polycaprolactone (PCL)-thiol ligand functionalization with flow-controlled microfluidic block copolymer self-assembly to produce biocompatible gold nanoparticle (GNP)-loaded micellar polymer nanoparticles (GNP-PNPs) in which GNPs are encapsulated within PCL cores surrounded by an external layer of poly(ethylene glycol) (PEG). By varying both the relative amount of block copolymer and the microfluidic flow rate, a series of GNP-PNPs are produced in which the mean number of GNPs per PNP in the < 50-nm fraction (Zave,d< 50 nm) varies between 0.1 and 1.9 while the external PEG surface is constant. Zave,d< 50 nm values are determined by statistical analysis of TEM images and compared with the results of cell uptake experiments on MDA-MB-231 cancer cells. For Zave,d< 50 nm ≤ 1 (including a control sample of individual GNPs also with a PEG surface layer), cell uptake is relatively constant, but increases sharply for Zave,d< 50 nm > 1, with a factor of 7 enhancement as Zave,d< 50 nm increases from 1 to ∼2. Enabled by the shear processing control provided by the microfluidic chip, these results provide the first evidence that cellular uptake can be enhanced specifically by increasing the number of GNPs per vector, with other parameters, including polymeric material, internal structure, and external surface chemistry, held constant. They also demonstrate a versatile platform for packaging GNPs in biocompatible polymeric carriers with flow-controlled formulation optimization for various therapeutic and diagnostic applications.
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Affiliation(s)
- Sundiata Kly
- Department of Chemistry, University of Victoria, PO Box 1700 Stn CSC, Victoria, BC V8W 2Y2, Canada
| | - Yuhang Huang
- Department of Chemistry, University of Victoria, PO Box 1700 Stn CSC, Victoria, BC V8W 2Y2, Canada
| | - Matthew G Moffitt
- Department of Chemistry, University of Victoria, PO Box 1700 Stn CSC, Victoria, BC V8W 2Y2, Canada.
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3
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Duan BH, Yu JX, Gao RT, Li SY, Liu N, Wu ZQ. Controlled synthesis of cyclic helical polyisocyanides and bottlebrush polymers using a cyclic alkyne-Pd(II) catalyst. Chem Commun (Camb) 2023; 59:13002-13005. [PMID: 37830293 DOI: 10.1039/d3cc04095j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2023]
Abstract
Cyclic polymers have very unique structure and properties, and thus have drawn intense research attention. However, controlled synthesis of cyclic polymers with predictable molar mass and narrow distribution is still a challenging task. In this study, we developed a novel cyclic catalyst that initiates the ring-expansion polymerisation of isocyanides, producing a series of cyclic helical polymers with predictable molecular weight and low dispersity. Interestingly, the ring-expansion polymerization of the isocyanide macromonomers gives well-defined cyclic bottlebrush polymers. The cyclic topology was demonstrated using transmission electron microscopy.
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Affiliation(s)
- Bing-Hui Duan
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, China.
| | - Jia-Xin Yu
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, China.
| | - Run-Tan Gao
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, China.
| | - Shi-Yi Li
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, China.
| | - Na Liu
- The School of Pharmaceutical Sciences, Jilin University, 1266 Fujin Road, Changchun, Jilin 130021, P. R. China.
| | - Zong-Quan Wu
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, China.
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4
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Levenson AM, Morrison CM, Huang PR, Wang TW, Carter-Schwendler Z, Golder MR. Ancillary Ligand Lability Improves Control in Cyclic Ruthenium Benzylidene Initiated Ring-Expansion Metathesis Polymerizations. ACS Macro Lett 2023; 12:1286-1292. [PMID: 37695322 DOI: 10.1021/acsmacrolett.3c00520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
The synthesis of well-defined cyclic polymers is crucial to exploring applications spanning engineering, energy, and biomedicine. These materials lack chain-ends and are therefore imbued with unique bulk properties. Despite recent advancements, the general methodology for controlled cyclic polymer synthesis via ring-expansion metathesis polymerization (REMP) remains challenging. Low initiator activity leads to high molar mass polymers at short reaction times that subsequently "evolve" to smaller polymeric products. In this work, we demonstrate that in situ addition of pyridine to the tethered ruthenium-benzylidene REMP initiator CB6 increases ancillary ligand lability to synthesize controlled and low dispersity cyclic poly(norbornene) on a short time scale without relying on molar mass evolution events.
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Affiliation(s)
- Adelaide M Levenson
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Christine M Morrison
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Pin-Ruei Huang
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Teng-Wei Wang
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Zak Carter-Schwendler
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Matthew R Golder
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
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5
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Miyairi M, Taniguchi T, Nishimura T, Maeda K. Facile Synthesis of Linear and Cyclic Poly(diphenylacetylene)s by Molybdenum and Tungsten Catalysis. Angew Chem Int Ed Engl 2023; 62:e202302332. [PMID: 37376740 DOI: 10.1002/anie.202302332] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 06/11/2023] [Accepted: 06/27/2023] [Indexed: 06/29/2023]
Abstract
Improved methods for the synthesis of linear and cyclic poly(diphenylacetylene)s by polymerization of the corresponding diphenylacetylenes using MoCl5 - and WCl4 -based catalytic systems have been developed. MoCl5 induces migratory insertion polymerization of diphenylacetylenes in the presence of arylation reagents such as Ph4 Sn and ArSnn Bu3 to produce cis-stereoregular linear poly(diphenylacetyelene)s with high molecular weights (number-average molar mass (Mn )=30,000-3,200,000) in good yields (up to 98 %). On the other hand, WCl4 induces ring expansion polymerization of diphenylacetylenes in the presence of Ph4 Sn or reducing reagents to produce cis-stereoregular cyclic poly(diphenylacetylene)s with high molecular weights (Mn =20,000-250,000) in moderate to good yields (up to 90 %). Both catalytic systems are applicable to the polymerization of various diphenylacetylenes having polar functional groups such as esters that are not efficiently polymerized by conventional methods using WCl6 -Ph4 Sn and TaCl5 -n Bu4 Sn systems.
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Affiliation(s)
- Mami Miyairi
- Graduate School of Natural Science and Technology, Kanazawa University Kakuma-machi, Kanazawa, 920-1192, Japan
| | - Tsuyoshi Taniguchi
- Graduate School of Natural Science and Technology, Kanazawa University Kakuma-machi, Kanazawa, 920-1192, Japan
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University Kakuma-machi, Kanazawa, 920-1192, Japan
| | - Tatsuya Nishimura
- Graduate School of Natural Science and Technology, Kanazawa University Kakuma-machi, Kanazawa, 920-1192, Japan
| | - Katsuhiro Maeda
- Graduate School of Natural Science and Technology, Kanazawa University Kakuma-machi, Kanazawa, 920-1192, Japan
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University Kakuma-machi, Kanazawa, 920-1192, Japan
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6
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Jakhar VK, Shen YH, Hyun SM, Esper AM, Ghiviriga I, Abboud KA, Lester DW, Veige AS. Improved Trianionic Pincer Ligand Synthesis for Cyclic Polymer Catalysts. Organometallics 2023. [DOI: 10.1021/acs.organomet.3c00060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
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7
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Zhang H, Zha H, Liu C, Hong C. Scalable preparation and direct visualization of cyclic polymers via self-folding cyclization technique. Sci China Chem 2022. [DOI: 10.1007/s11426-022-1344-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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8
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Ochs J, Pagnacco CA, Barroso-Bujans F. Macrocyclic polymers: Synthesis, purification, properties and applications. Prog Polym Sci 2022. [DOI: 10.1016/j.progpolymsci.2022.101606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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9
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Chen C, Weil T. Cyclic polymers: synthesis, characteristics, and emerging applications. NANOSCALE HORIZONS 2022; 7:1121-1135. [PMID: 35938292 DOI: 10.1039/d2nh00242f] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Cyclic polymers with a ring-like topology and no chain ends are a unique class of macromolecules. In the past several decades, significant advances have been made to prepare these fascinating polymers, which allow for the exploration of their topological effects and potential applications in various fields. In this Review, we first describe representative synthetic strategies for making cyclic polymers and their derivative topological polymers with more complex structures. Second, the unique physical properties and self-assembly behavior of cyclic polymers are discussed by comparing them with their linear analogues. Special attention is paid to highlight how polymeric rings can assemble into hierarchical macromolecular architectures. Subsequently, representative applications of cyclic polymers in different fields such as drug and gene delivery and surface functionalization are presented. Last, we envision the following key challenges and opportunities for cyclic polymers that may attract future attention: large-scale synthesis, efficient purification, programmable folding and assembly, and expansion of applications.
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Affiliation(s)
- Chaojian Chen
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
- Department of Chemistry and International Institute for Nanotechnology, Northwestern University, Evanston, Illinois 60208, USA
| | - Tanja Weil
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
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10
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Pal D, Garrison JB, Miao Z, Diodati LE, Veige AS, Sumerlin BS. Nanobowls from Amphiphilic Core–Shell Cyclic Bottlebrush Polymers. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c01232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Digvijayee Pal
- George & Josephine Butler Polymer Research Laboratory, Center for Macromolecular Science & Engineering, Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611, United States
| | - John B. Garrison
- George & Josephine Butler Polymer Research Laboratory, Center for Macromolecular Science & Engineering, Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611, United States
| | - Zhihui Miao
- George & Josephine Butler Polymer Research Laboratory, Center for Macromolecular Science & Engineering, Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611, United States
- Center for Catalysis, Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611, United States
| | - Lily E. Diodati
- George & Josephine Butler Polymer Research Laboratory, Center for Macromolecular Science & Engineering, Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611, United States
| | - Adam S. Veige
- George & Josephine Butler Polymer Research Laboratory, Center for Macromolecular Science & Engineering, Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611, United States
- Center for Catalysis, Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611, United States
| | - Brent S. Sumerlin
- George & Josephine Butler Polymer Research Laboratory, Center for Macromolecular Science & Engineering, Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611, United States
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11
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Jakhar VK, Esper AM, Ghiviriga I, Abboud KA, Ehm C, Veige AS. Isolation of an Elusive Phosphametallacyclobutadiene and Its Role in Reversible Carbon−Carbon Bond Cleavage. Angew Chem Int Ed Engl 2022; 61:e202203073. [PMID: 35536109 PMCID: PMC9296546 DOI: 10.1002/anie.202203073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Indexed: 11/11/2022]
Abstract
The reactivity of phosphaalkynes, the isolobal and isoelectronic congeners to alkynes, with metal alkylidyne complexes is explored in this work. Treating the tungsten alkylidyne [t BuOCO]W≡Ct Bu(THF)2 (1) with phosphaalkyne (10) results in the formation of [O2 C(t BuC=)W{η2 -(P,C)-P≡C-Ad}(THF)] (13-t BuTHF ) and [O2 C(AdC=)W{η2 -(P,C)-P≡C-t Bu}(THF)] (13-AdTHF ); derived from the formal reductive migratory insertion of the alkylidyne moiety into a W-Carene bond. Analogous to alkyne metathesis, a stable phosphametallacyclobutadiene complex [t BuOCO]W[κ2 -C(t Bu)PC(Ad)] (14) forms upon loss of THF from the coordination sphere of either 13-t BuTHF or 13-AdTHF . Remarkably, the C-C bonds reversibly form/cleave with the addition or removal of THF from the coordination sphere of the formal tungsten(VI) metal center, permitting unprecedented control over the transformation of a tetraanionic pincer to a trianionic pincer and back. Computational analysis offers thermodynamic and electronic reasoning for the reversible equilibrium between 13-t Bu/AdTHF and 14.
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Affiliation(s)
- Vineet K. Jakhar
- Department of Chemistry University of Florida Center for Catalysis P.O. Box 117200 Gainesville FL 32611 USA
| | - Alec M. Esper
- Department of Chemistry University of Florida Center for Catalysis P.O. Box 117200 Gainesville FL 32611 USA
| | - Ion Ghiviriga
- Department of Chemistry University of Florida Center for Catalysis P.O. Box 117200 Gainesville FL 32611 USA
| | - Khalil A. Abboud
- Department of Chemistry University of Florida Center for Catalysis P.O. Box 117200 Gainesville FL 32611 USA
| | - Christian Ehm
- Dipartimento di Scienze Chimiche Università di Napoli Federico II Via Cintia 80126 Napoli Italy
| | - Adam S. Veige
- Department of Chemistry University of Florida Center for Catalysis P.O. Box 117200 Gainesville FL 32611 USA
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12
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Jakhar VK, Esper AM, Ghiviriga I, Abboud KA, Ehm C, Veige AS. Isolation of an Elusive Phosphametallacyclobutadiene and Its Role in Reversible Carbon−Carbon Bond Cleavage. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202203073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Vineet K. Jakhar
- Department of Chemistry University of Florida Center for Catalysis P.O. Box 117200 Gainesville FL 32611 USA
| | - Alec M. Esper
- Department of Chemistry University of Florida Center for Catalysis P.O. Box 117200 Gainesville FL 32611 USA
| | - Ion Ghiviriga
- Department of Chemistry University of Florida Center for Catalysis P.O. Box 117200 Gainesville FL 32611 USA
| | - Khalil A. Abboud
- Department of Chemistry University of Florida Center for Catalysis P.O. Box 117200 Gainesville FL 32611 USA
| | - Christian Ehm
- Dipartimento di Scienze Chimiche Università di Napoli Federico II Via Cintia 80126 Napoli Italy
| | - Adam S. Veige
- Department of Chemistry University of Florida Center for Catalysis P.O. Box 117200 Gainesville FL 32611 USA
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13
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Garrison JB, Hughes RW, Sumerlin BS. Backbone Degradation of Polymethacrylates via Metal-Free Ambient-Temperature Photoinduced Single-Electron Transfer. ACS Macro Lett 2022; 11:441-446. [PMID: 35575327 DOI: 10.1021/acsmacrolett.2c00091] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Polymeric materials comprised of all-carbon backbones are ubiquitous to modern society due to their low cost, impressive robustness, and unparalleled physical properties. It is well-known that these materials often persist long beyond their intended usage lifetime, resulting in environmental accumulation of plastic waste. A substantial barrier to the breakdown of these polymers is the relative chemical inertness of carbon-carbon bonds within their backbone. Herein, we describe a photocatalytic strategy for cleaving carbon-based polymer backbones. Inclusion of a low mole percent of a redox-active comonomer allows for a dramatic reduction in polymer molecular weight upon exposure to light. The N-(acyloxy)phthalimide comonomer, upon reception of an electron from a single-electron transfer (SET) donor, undergoes decarboxylation to yield a backbone-centered radical. Depending on the nature of this backbone radical, as well as the substitution on neighboring monomer repeat units, a β-scission pathway is thermodynamically favored, resulting in backbone cleavage. In this way, polymers with an all-carbon backbone may be degraded at ambient temperature under metal-free conditions.
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Affiliation(s)
- John B. Garrison
- George & Josephine Butler Polymer Research Laboratory, Center for Macromolecular Science & Engineering, Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States
| | - Rhys W. Hughes
- George & Josephine Butler Polymer Research Laboratory, Center for Macromolecular Science & Engineering, Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States
| | - Brent S. Sumerlin
- George & Josephine Butler Polymer Research Laboratory, Center for Macromolecular Science & Engineering, Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States
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14
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Ferreira RMM, Ambrosi A, Conceição TF. Post‐polymerization modification of polyetherimide by
Friedel‐Crafts
acylation:
Physical–chemical
characterization and performance as gas separation membrane. J Appl Polym Sci 2022. [DOI: 10.1002/app.52330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
| | - Alan Ambrosi
- Laboratory of Membrane Processes, Department of Chemical and Food Engineering Federal University of Santa, Catarina University Campus Florianópolis Brazil
| | - Thiago Ferreira Conceição
- Department of Chemistry Federal University of Santa Catarina, University Campus Florianópolis Brazil
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15
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Golder MR, Morrison CM. Ring-Expansion Metathesis Polymerization Initiator Design for the Synthesis of Cyclic Polymers. Synlett 2022. [DOI: 10.1055/s-0041-1737802] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
AbstractCyclic polymers are of increasing interest to the synthetic and physical polymer communities due to their unique structures that lack chain ends. This topological distinction results in decreased chain entanglement, lower intrinsic viscosity, and smaller hydrodynamic radii. Many methods for the production of cyclic polymers exist, however, large-scale production of architecturally pure cyclic polymers is challenging. Ring-expansion metathesis polymerization (REMP) is an increasingly promising method to produce cyclic polymers because of the mild and scalable reaction conditions. Herein, a brief history of REMP for the synthesis of cyclic polymers with both ruthenium and non-ruthenium initiators is discussed. Even though REMP is a promising method for synthesizing cyclic polymers, state-of-the-art methods still struggle with poor molar mass control, slow polymerization rates, low conversion, and poor initiator stability. To combat these challenges, our group has developed a tethered ruthenium-benzylidene initiator, CB6, which utilizes design features from ubiquitous Grubbs-type initiators used in linear polymerizations. These structural modifications are shown to improve initiator kinetics, enhance initiator stability, and increase control over the molar mass of the resulting cyclic polymers.1 Introduction2 Ring-Expansion Metathesis Polymerization (REMP) with Ruthenium Initiators3 New Developments in Ruthenium Ring-Expansion Metathesis (REMP) Initiator Design4 Ring-Expansion Metathesis Polymerization (REMP) with Non-Ruthenium Initiators5 Conclusions
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16
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Zhang M, Wu J, Li Z, Hou W, Li Y, Shi Y, Chen Y. Synthesis and Visualization of bottlebrush-shaped segmented hyperbranched polymers. Polym Chem 2022. [DOI: 10.1039/d2py00898j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Visualization of single molecular morphology provides an intuitive evidence to understand the relationships of molecular structure-synthetic method. Herein, by combining the architectural features of molecular bottlebrush (MBB) and segmented hyperbranched...
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17
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18
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Mandal U, Ghiviriga I, Abboud KA, Lester DW, Veige AS. Double Tethered Metallacyclobutane Catalyst for Cyclic Polymer Synthesis. J Am Chem Soc 2021; 143:17276-17283. [PMID: 34618432 DOI: 10.1021/jacs.1c08806] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This work outlines an approach to creating a catalyst for cyclic polymer synthesis using readily available materials in only one or two steps. Combining commercially available molybdenum-alkylidene 1 with two equivalents of ene-ol proligand 2 rapidly produces, in quantitative yield (1H NMR spectroscopy), the double tethered metallacyclobutane complex 3. Characterized by variable temperature NMR studies and nuclear Overhauser effect spectroscopy (NOESY) experiments, complex 3 exhibits fluxional behavior in solution. Determined by single crystal X-ray diffraction, the solid-state structure of complex 3 reveals metrical parameters indicating that the metallacyclobutane is not predicted to undergo rapid retro-cycloaddition. However, complex 3 is a precatalyst for the polymerization of norbornene to produce cyclic polynorbornene. An NMR spectrum of a test polymerization indicates that only a small fraction of the precatalyst is activated upon exposure to monomer. Quantifying the active catalyst is possible by measuring vinyl resonances that appear in the 1H NMR spectrum. The vinyl resonances are attributable to the release of one of the tethers upon norbornene addition. Confirmation of the polymer cyclic topology comes from gel permeation chromatography (GPC), dynamic light scattering (DLS), and intrinsic viscosity (η) measurements. The double tethered metallacyclobutane complex is a novel design for catalytic cyclic polymer synthesis. The synthetic approach suggests that catalyst tuning is possible by a choice of the commercial alkylidene and alteration of the ene-ol proligand.
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Affiliation(s)
- Ushnish Mandal
- Department of Chemistry, Center for Catalysis, University of Florida, P.O. Box 117200, Gainesville, Florida 32611, United States
| | - Ion Ghiviriga
- Department of Chemistry, Center for NMR Spectroscopy, University of Florida, P.O. Box 117200, Gainesville, Florida 32611, United States
| | - Khalil A Abboud
- Department of Chemistry, Center for Catalysis, University of Florida, P.O. Box 117200, Gainesville, Florida 32611, United States
| | - Daniel W Lester
- Polymer Characterization Research Technology Platform, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Adam S Veige
- Department of Chemistry, Center for Catalysis, University of Florida, P.O. Box 117200, Gainesville, Florida 32611, United States
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19
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Sueyoshi S, Taniguchi T, Tanaka S, Asakawa H, Nishimura T, Maeda K. Understanding the Polymerization of Diphenylacetylenes with Tantalum(V) Chloride and Cocatalysts: Production of Cyclic Poly(diphenylacetylene)s by Low-Valent Tantalum Species Generated in Situ. J Am Chem Soc 2021; 143:16136-16146. [PMID: 34499837 DOI: 10.1021/jacs.1c06811] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A systematic investigation of the polymerization of representative diphenylacetylenes with TaCl5 and cocatalysts suggested that low-valent Ta species, which are formed by in situ reduction of TaCl5 by the cocatalysts, are involved in the polymerization and that the polymerization reaction proceeds by an insertion ring expansion mechanism via the formation of tantalacyclopentadiene intermediates, rather than the previously considered metathesis mechanism. This polymerization mechanism indicates the production of unprecedented cis-stereoregular cyclic poly(diphenylacetylene)s. Indeed, the possibilities of a cyclic structure and high cis-stereoregularity of the resulting polymers were reasonably supported by the results of their detailed atomic force microscopy (AFM) and NMR analyses, respectively.
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Affiliation(s)
- Shingyo Sueyoshi
- Graduate School of Frontier Science Initiative, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Tsuyoshi Taniguchi
- Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Saki Tanaka
- Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Hitoshi Asakawa
- Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan.,Nanomaterials Research Institute (NanoMaRi), Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan.,Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Tatsuya Nishimura
- Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Katsuhiro Maeda
- Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan.,Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
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20
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Miao Z, Konar D, Sumerlin BS, Veige AS. Soluble Polymer Precursors via Ring-Expansion Metathesis Polymerization for the Synthesis of Cyclic Polyacetylene. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c00938] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Zhihui Miao
- Center for Catalysis, Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611, United States
- George & Josephine Butler Polymer Research Laboratory, Center for Macromolecular Science & Engineering, Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611, United States
| | - Debabrata Konar
- George & Josephine Butler Polymer Research Laboratory, Center for Macromolecular Science & Engineering, Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611, United States
| | - Brent S. Sumerlin
- George & Josephine Butler Polymer Research Laboratory, Center for Macromolecular Science & Engineering, Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611, United States
| | - Adam S. Veige
- Center for Catalysis, Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611, United States
- George & Josephine Butler Polymer Research Laboratory, Center for Macromolecular Science & Engineering, Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611, United States
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21
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Tan Y, Song J. Independent and Synergistic Modulations of Viscoelasticity and Stiffness of Dynamically Cross-Linked Cell-Encapsulating ClickGels by Covalently Tethered Polymer Brushes. Biomacromolecules 2021; 22:3408-3415. [PMID: 34292720 DOI: 10.1021/acs.biomac.1c00477] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report independent and synergistic modulations of the stiffness and viscoelasticity of ClickGels, formed by a combination of the bio-orthogonal covalent and dynamic noncovalent cross-linking, by covalently incorporating nonionic, zwitterionic, or anionic polymer brushes. Tethering nonionic and zwitterionic brushes at the cost of noncovalent cross-linking increased stiffness and slowed stress relaxation, respectively, without altering the other properties. Meanwhile, tethering anionic brushes significantly increased ClickGel stiffness, while also slowing its stress relaxation. ClickGels with faster stress relaxation, not reduced stiffness, promoted short-term (24 h) viability and YAP/TAZ nuclear localization of encapsulated bone marrow-derived stromal cells (BMSCs). In contrast, ClickGel stiffness, not viscoelasticity, inversely correlated to the short-term dehydrogenase activity of encapsulated BMSCs. This work highlights the role of the ionic state of polymer brushes in modulating the hydrogel elastic modulus and viscoelasticity and establishes the brush-modified ClickGel as a facile and reproducible tool for manipulating mechanical cues of the synthetic cellular niche.
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Affiliation(s)
- Yu Tan
- Department of Orthopedics & Physical Rehabilitation, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, Massachusetts 01655, United States
| | - Jie Song
- Department of Orthopedics & Physical Rehabilitation, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, Massachusetts 01655, United States
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22
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Miao Z, Gonsales SA, Ehm C, Mentink-Vigier F, Bowers CR, Sumerlin BS, Veige AS. Cyclic polyacetylene. Nat Chem 2021; 13:792-799. [PMID: 34083779 DOI: 10.1038/s41557-021-00713-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 04/26/2021] [Indexed: 02/06/2023]
Abstract
Here we demonstrate the synthesis of cyclic polyacetylene (c-PA), or [∞]annulene, via homogeneous tungsten-catalysed polymerization of acetylene. Unique to the cyclic structure and evidence for its topology, the c-PA contains >99% trans double bonds, even when synthesized at -94 °C. High activity with low catalyst loadings allows for the synthesis of temporarily soluble c-PA, thus opening the opportunity to derivatize the polymer in solution. Absolute evidence for the cyclic topology comes from atomic force microscopy images of bottlebrush derivatives generated from soluble c-PA. Now available in its cyclic form, initial characterization studies are presented to elucidate the topological differences compared with traditionally synthesized linear polyacetylene. One advantage to the synthesis of c-PA is the direct synthesis of the trans-transoid isomer. Low defect concentrations, low soliton concentration, and relatively high conjugation lengths are characteristics of c-PA. Efficient catalysis permits the rapid synthesis of lustrous flexible thin films of c-PA, and when doped with I2, they are highly conductive (398 (±76) Ω-1 cm-1).
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Affiliation(s)
- Zhihui Miao
- Department of Chemistry, University of Florida, Center for Catalysis, Gainesville, FL, USA.,Department of Chemistry, George and Josephine Butler Polymer Research Laboratory, Center for Macromolecular Science and Engineering, University of Florida, Gainesville, FL, USA
| | - Stella A Gonsales
- Department of Chemistry, University of Florida, Center for Catalysis, Gainesville, FL, USA
| | - Christian Ehm
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Naples, Italy
| | | | - Clifford R Bowers
- Department of Chemistry, University of Florida, Center for Catalysis, Gainesville, FL, USA
| | - Brent S Sumerlin
- Department of Chemistry, George and Josephine Butler Polymer Research Laboratory, Center for Macromolecular Science and Engineering, University of Florida, Gainesville, FL, USA.
| | - Adam S Veige
- Department of Chemistry, University of Florida, Center for Catalysis, Gainesville, FL, USA. .,Department of Chemistry, George and Josephine Butler Polymer Research Laboratory, Center for Macromolecular Science and Engineering, University of Florida, Gainesville, FL, USA.
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23
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Wang TW, Huang PR, Chow JL, Kaminsky W, Golder MR. A Cyclic Ruthenium Benzylidene Initiator Platform Enhances Reactivity for Ring-Expansion Metathesis Polymerization. J Am Chem Soc 2021; 143:7314-7319. [PMID: 33960766 DOI: 10.1021/jacs.1c03491] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Ring-expansion metathesis polymerization (REMP) has shown potential as an efficient strategy to access cyclic macromolecules. Current approaches that utilize cyclic olefin feedstocks suffer from poor functional group tolerance, low initiator stability, and slow reaction kinetics. Improvements to current initiators will address these issues in order to develop more versatile and user-friendly technologies. Herein, we report a reinvigorated tethered ruthenium-benzylidene initiator, CB6, that utilizes design features from ubiquitous Grubbs-type initiators that are regularly applied in linear polymerizations. We report the controlled synthesis of functionalized cyclic poly(norbornene)s and demonstrate that judicious ligand modifications not only greatly improve kinetics but also lead to enhanced initiator stability. Overall, CB6 is an adaptable platform for the study and application of cyclic macromolecules via REMP.
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24
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Jakhar V, Pal D, Ghiviriga I, Abboud KA, Lester DW, Sumerlin BS, Veige AS. Tethered Tungsten-Alkylidenes for the Synthesis of Cyclic Polynorbornene via Ring Expansion Metathesis: Unprecedented Stereoselectivity and Trapping of Key Catalytic Intermediates. J Am Chem Soc 2021; 143:1235-1246. [PMID: 33417768 DOI: 10.1021/jacs.0c12248] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
This report describes an approach for preparing tethered tungsten-imido alkylidene complexes featuring a tetra-anionic pincer ligand. Treating the tungsten alkylidyne [tBuOCO]W≡CtBu(THF)2 (1) with isocyanates (RNCO; R = tBu, Cy, and Ph) leads to cycloaddition occurring exclusively at the C═N bond to generate the tethered tungsten-imido alkylidenes (6-NR). Unanticipated intermediates reveal themselves, including the discovery of [(O2CtBuC═)W(η2-(N,C)-RNCO)(THF)] (11-R) and an unprecedented decarbonylation product [(tBuOCO)W(≡NR)(tBuCCO)] (14-R), on the pathway to the formation of 6-NR. Complex 11-R is kinetically stable for sterically bulky isocyanate R = tBu (11-tBu) and is isolated and characterized by single-crystal X-ray diffraction. Finally, adding to the short list of catalysts capable of ring expansion metathesis polymerization (REMP), complexes 6-NR and 11-tBu are active for the stereoselective synthesis of cyclic polynorbornene.
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Affiliation(s)
- Vineet Jakhar
- Department of Chemistry, Center for Catalysis, University of Florida, P.O. Box 117200, Gainesville, Florida 32611, United States
| | - Digvijayee Pal
- George and Josephine Butler Polymer Research Laboratory, Center for Macromolecular Science and Engineering, University of Florida, P.O. Box 117200, Gainesville, Florida 32611, United States
| | - Ion Ghiviriga
- Department of Chemistry, Center for Catalysis, University of Florida, P.O. Box 117200, Gainesville, Florida 32611, United States
| | - Khalil A Abboud
- Department of Chemistry, Center for Catalysis, University of Florida, P.O. Box 117200, Gainesville, Florida 32611, United States
| | - Daniel W Lester
- Polymer Characterization Research Technology Platform, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Brent S Sumerlin
- George and Josephine Butler Polymer Research Laboratory, Center for Macromolecular Science and Engineering, University of Florida, P.O. Box 117200, Gainesville, Florida 32611, United States
| | - Adam S Veige
- Department of Chemistry, Center for Catalysis, University of Florida, P.O. Box 117200, Gainesville, Florida 32611, United States
- George and Josephine Butler Polymer Research Laboratory, Center for Macromolecular Science and Engineering, University of Florida, P.O. Box 117200, Gainesville, Florida 32611, United States
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25
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Wang TW, Golder MR. Advancing macromolecular hoop construction: recent developments in synthetic cyclic polymer chemistry. Polym Chem 2021. [DOI: 10.1039/d0py01655a] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Synthetic methodology to access cyclic macromolecules continues to develop via two distinct mechanistic classes: ring-expansion of macrocyclic initiators and ring-closure of functionalized linear polymers.
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Affiliation(s)
- Teng-Wei Wang
- Department of Chemistry
- University of Washington
- Seattle
- USA
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