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Mandal D, Qu ZW, Grimme S, Stephan DW. Electron-deficient cyclopropenium cations as Lewis acids in FLP chemistry. Chem Commun (Camb) 2023; 59:10508-10511. [PMID: 37564033 DOI: 10.1039/d3cc02684a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
Cyclopropenium cations incorporating electron deficient substituents are Lewis acidic despite the presence of π-electrons. The chloride and electron affinities are examined computationally and experimentally, respectively. These cations form classic Lewis acid-base adducts with PPh3, while sterically demanding phosphines yield frustrated Lewis pairs (FLPs) which participate in FLP additions. Depending on the basicity of the phosphine used, addition to alkynes or alkyne deprotonation is observed. In either case, new C-C bonds are formed, thus extending the utility of the concept of FLP chemistry to these delocalized π-cations.
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Affiliation(s)
- Dipendu Mandal
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, Zhejiang, China
- Department of Chemistry, University of Toronto, Toronto, 80 St. George Street, Ontario M5S 3H6, Canada.
| | - Zheng-Wang Qu
- Mulliken Center for Theoretical Chemistry, Clausius Institut für Physikalische und Theoretische Chemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Beringstrasse 4, Bonn 53115, Germany.
| | - Stefan Grimme
- Mulliken Center for Theoretical Chemistry, Clausius Institut für Physikalische und Theoretische Chemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Beringstrasse 4, Bonn 53115, Germany.
| | - Douglas W Stephan
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, Zhejiang, China
- Department of Chemistry, University of Toronto, Toronto, 80 St. George Street, Ontario M5S 3H6, Canada.
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2
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Smajlagic I, White B, Azeez O, Pilkington M, Dudding T. Organocatalysis Linked to Charge-Enhanced Acidity with Superelectrophilic Traits. ACS Catal 2022. [DOI: 10.1021/acscatal.1c05296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ivor Smajlagic
- Department of Chemistry, Brock University, St. Catharines L2S 3A1, Canada
| | - Brandon White
- Department of Chemistry, Brock University, St. Catharines L2S 3A1, Canada
| | - Oyindamola Azeez
- Department of Chemistry, Brock University, St. Catharines L2S 3A1, Canada
| | - Melanie Pilkington
- Department of Chemistry, Brock University, St. Catharines L2S 3A1, Canada
| | - Travis Dudding
- Department of Chemistry, Brock University, St. Catharines L2S 3A1, Canada
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3
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Ranga PK, Ahmad F, Singh G, Tyagi A, Vijaya Anand R. Recent advances in the organocatalytic applications of cyclopropene- and cyclopropenium-based small molecules. Org Biomol Chem 2021; 19:9541-9564. [PMID: 34704583 DOI: 10.1039/d1ob01549d] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The development of novel small molecule-based catalysts for organic transformations has increased noticeably in the last two decades. A very recent addition to this particular research area is cyclopropene- and cyclopropenium-based catalysts. At one point in time, particularly in the mid-20th century, much attention was focused on the structural aspects and physical properties of cyclopropene-based compounds. However, a paradigm shift was observed in the late 20th century, and the focus shifted to the synthetic utility of these compounds. In fact, a wide range of cyclopropene derivatives have been found serving as valuable synthons for the construction of carbocycles, heterocycles and other useful organic compounds. In the last few years, the catalytic applications of cyclopropene/cyclopropenium-based compounds have been uncovered and many synthetic protocols have been developed using cyclopropene-based compounds as organocatalysts. Therefore, the main objective of this review is to highlight recent developments in the catalytic applications of cyclopropene-based small molecules in different areas of organocatalysis such as phase-transfer catalysis (PTC), Brønsted base catalysis, hydrogen-bond donor catalysis, nucleophilic carbene catalysis, and electrophotocatalysis developed within the past two decades.
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Affiliation(s)
- Pavit K Ranga
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, Knowledge City, S.A.S Nagar, Manauli (PO), Punjab - 140306, India.
| | - Feroz Ahmad
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, Knowledge City, S.A.S Nagar, Manauli (PO), Punjab - 140306, India.
| | - Gurdeep Singh
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, Knowledge City, S.A.S Nagar, Manauli (PO), Punjab - 140306, India.
| | - Akshi Tyagi
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, Knowledge City, S.A.S Nagar, Manauli (PO), Punjab - 140306, India.
| | - Ramasamy Vijaya Anand
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, Knowledge City, S.A.S Nagar, Manauli (PO), Punjab - 140306, India.
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4
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Vemulapalli S, Guest M, Smajlagic I, Dudding T. p Ka Scale for Cyclopropenium Ions with Applications in CO 2 Capture. J Org Chem 2021; 86:11835-11844. [PMID: 34369775 DOI: 10.1021/acs.joc.1c01255] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Molecular acid-base properties are core to understanding chemical systems and the prediction of reactivity. This axiom holds for cyclopropenium ions in terms of their broad use as (organo)catalysts, ligands, redox-flow batteries, and applications in materials sciences. In view of this significant status, and with it, the critical importance of acidity, we disclose in this report the first comprehensive computational study of the pKa values of cyclopropenium ions employing a subset of 70 structurally diverse cyclopropenium derivatives, density functional computations, and Hammett linear free-energy relationships. Capitalizing upon these computed findings, and with an eye toward greenhouse gas trapping, we further document the timely use of a cyclopropenium-cyclopropenylidene coupled platform for CO2 capture and light-triggered release.
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Affiliation(s)
- Srini Vemulapalli
- Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario L2S 3A1, Canada
| | - Matt Guest
- Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario L2S 3A1, Canada
| | - Ivor Smajlagic
- Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario L2S 3A1, Canada
| | - Travis Dudding
- Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario L2S 3A1, Canada
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5
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Belding L, Root SE, Li Y, Park J, Baghbanzadeh M, Rojas E, Pieters PF, Yoon HJ, Whitesides GM. Conformation, and Charge Tunneling through Molecules in SAMs. J Am Chem Soc 2021; 143:3481-3493. [DOI: 10.1021/jacs.0c12571] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Lee Belding
- Department of Chemistry and Chemical Biology, Harvard University 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Samuel E. Root
- Department of Chemistry and Chemical Biology, Harvard University 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Yuan Li
- Department of Chemistry and Chemical Biology, Harvard University 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Junwoo Park
- Department of Chemistry and Chemical Biology, Harvard University 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Mostafa Baghbanzadeh
- Department of Chemistry and Chemical Biology, Harvard University 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Edwin Rojas
- Department of Chemistry and Chemical Biology, Harvard University 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Priscilla F. Pieters
- Department of Chemistry and Chemical Biology, Harvard University 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Hyo Jae Yoon
- Department of Chemistry, Korea University, Seoul 02841, Korea
| | - George M. Whitesides
- Department of Chemistry and Chemical Biology, Harvard University 12 Oxford Street, Cambridge, Massachusetts 02138, United States
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6
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Guest M, Mir R, Foran G, Hickson B, Necakov A, Dudding T. Trisaminocyclopropenium Cations as Small-Molecule Organic Fluorophores: Design Guidelines and Bioimaging Applications. J Org Chem 2020; 85:13997-14011. [PMID: 32930593 DOI: 10.1021/acs.joc.0c02026] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The discovery of fluorescence two centuries ago ushered in, what is today, an illuminating field of science rooted in the rational design of photochromic molecules for task-specific bio-, material-, and medical-driven applications. Today, this includes applications in bioimaging and diagnosis, photodynamic therapy regimes, in addition to photovoltaic devices and solar cells, among a vast multitude of other usages. In furthering this indispensable area of daily life and modern-day scientific research, we report herein the synthesis of a class of trisaminocyclopropenium fluorophores along with a systematic investigation of their unique molecular and electronic dependent photophysical properties. Among these fluorophores, tris[N(naphthalen-2-ylmethyl)phenylamino] cyclopropenium chloride (TNTPC) displayed a strong photophysical profile including a 0.92 quantum yield ascribed to intramolecular charge transfer and intramolecular through-space conjugation. Moreover, this cyclopropenium-based fluorophore functions as a competent imaging agent for DNA visualization and nuclear counterstaining in cell culture. To facilitate the broader use of these compounds, design principles supported by density functional theory calculations for engineering analogs of this class of fluorophores are offered. Collectively, this study adds to the burgeoning interest in cyclopropenium compounds and their unique properties as fluorophores with uses in bioimaging applications.
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Affiliation(s)
- Matt Guest
- Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario L2S 3A1, Canada
| | - Roya Mir
- Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario L2S 3A1, Canada
| | - Gregory Foran
- Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario L2S 3A1, Canada
| | - Brianne Hickson
- Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario L2S 3A1, Canada
| | - Aleksandar Necakov
- Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario L2S 3A1, Canada
| | - Travis Dudding
- Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario L2S 3A1, Canada
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8
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Litterscheidt J, Bandar JS, Ebert M, Forschner R, Bader K, Lambert TH, Frey W, Bühlmeyer A, Brändle M, Schulz F, Laschat S. Self-Assembly of Aminocyclopropenium Salts: En Route to Deltic Ionic Liquid Crystals. Angew Chem Int Ed Engl 2020; 59:10557-10565. [PMID: 32119178 PMCID: PMC7317216 DOI: 10.1002/anie.202000824] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 02/25/2020] [Indexed: 01/27/2023]
Abstract
Aminocyclopropenium ions have raised much attention as organocatalysts and redox active polymers. However, the self-assembly of amphiphilic aminocyclopropenium ions remains challenging. The first deltic ionic liquid crystals based on aminocyclopropenium ions have been developed. Differential scanning calorimetry, polarizing optical microscopy and X-ray diffraction provided insight into the unique self-assembly and nanosegregation of these liquid crystals. While the combination of small headgroups with linear p-alkoxyphenyl units led to bilayer-type smectic mesophases, wedge-shaped units resulted in columnar mesophases. Upon increasing the size and polyphilicity of the aminocyclopropenium headgroup, a lamellar phase was formed.
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Affiliation(s)
- Juri Litterscheidt
- Institute of Organic ChemistryUniversity of StuttgartPfaffenwaldring 5570569StuttgartGermany
| | - Jeffrey S. Bandar
- Department of ChemistryColorado State UniversityFort CollinsCO80523USA
| | - Max Ebert
- Institute of Organic ChemistryUniversity of StuttgartPfaffenwaldring 5570569StuttgartGermany
| | - Robert Forschner
- Institute of Organic ChemistryUniversity of StuttgartPfaffenwaldring 5570569StuttgartGermany
| | - Korinna Bader
- Institute of Organic ChemistryUniversity of StuttgartPfaffenwaldring 5570569StuttgartGermany
| | - Tristan H. Lambert
- Department of Chemistry & Chemical BiologyCornell University122 Baker LaboratoryIttacaNY14853USA
- Department of ChemistryColumbia UniversityNew YorkNY10027USA
| | - Wolfgang Frey
- Institute of Organic ChemistryUniversity of StuttgartPfaffenwaldring 5570569StuttgartGermany
| | - Andrea Bühlmeyer
- Institute of Organic ChemistryUniversity of StuttgartPfaffenwaldring 5570569StuttgartGermany
| | - Marcus Brändle
- Institute of Organic ChemistryUniversity of StuttgartPfaffenwaldring 5570569StuttgartGermany
| | - Finn Schulz
- Institute of Organic ChemistryUniversity of StuttgartPfaffenwaldring 5570569StuttgartGermany
| | - Sabine Laschat
- Institute of Organic ChemistryUniversity of StuttgartPfaffenwaldring 5570569StuttgartGermany
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9
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Litterscheidt J, Bandar JS, Ebert M, Forschner R, Bader K, Lambert TH, Frey W, Bühlmeyer A, Brändle M, Schulz F, Laschat S. Self‐Assembly of Aminocyclopropenium Salts: En Route to Deltic Ionic Liquid Crystals. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202000824] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Juri Litterscheidt
- Institute of Organic Chemistry University of Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Jeffrey S. Bandar
- Department of Chemistry Colorado State University Fort Collins CO 80523 USA
| | - Max Ebert
- Institute of Organic Chemistry University of Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Robert Forschner
- Institute of Organic Chemistry University of Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Korinna Bader
- Institute of Organic Chemistry University of Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Tristan H. Lambert
- Department of Chemistry & Chemical Biology Cornell University 122 Baker Laboratory Ittaca NY 14853 USA
- Department of Chemistry Columbia University New York NY 10027 USA
| | - Wolfgang Frey
- Institute of Organic Chemistry University of Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Andrea Bühlmeyer
- Institute of Organic Chemistry University of Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Marcus Brändle
- Institute of Organic Chemistry University of Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Finn Schulz
- Institute of Organic Chemistry University of Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Sabine Laschat
- Institute of Organic Chemistry University of Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
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10
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Guest M, Le Sueur R, Pilkington M, Dudding T. Development of an Unsymmetrical Cyclopropenimine-Guanidine Platform for Accessing Strongly Basic Proton Sponges and Boron-Difluoride Diaminonaphthalene Fluorophores. Chemistry 2020; 26:8608-8620. [PMID: 32319110 DOI: 10.1002/chem.202001227] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 04/18/2020] [Indexed: 01/06/2023]
Abstract
An unsymmetrical guanidine-cyclopropenimine proton sponge DAGUN and the related BF2 -chelate DAGBO are reported. Insight into the structural, electronic, bonding and photophysical properties of these two molecules are presented. Joint experimental and theoretical studies reveal the protonated form of DAGUN possesses an intramolecular N⋅⋅⋅H-N hydrogen bond which affords a high experimental pKBH+ of 26.6 (computed=26.3). Photophysical studies show that in solution DAGUN displays a green emission at 534 nm, with a large Stokes shift of 235 nm (14,718 cm-1 ). In contrast, the conjugate acid DAGUN-H+ is only weakly emissive due to attenuated intramolecular charge transfer. X-ray diffraction studies reveal that DAGBO contains a stable tetracoordinate boronium cation, reminiscent of the well-established BODIPY family of dyes. In solution, DAGBO exhibits a strong blue emission at 450 nm coupled with a large Stokes shift (Δλ=158 nm, Δν=11,957 cm-1 ) and quantum yield of 62 %, upon excitation at 293 nm. DAGBO sets the stage as the first entry into a new class of boron-difluoride diaminonaphthalenes (BOFDANs) that represent highly fluorescent and tunable next-generation dyes with future promise for biosensing and bioimaging applications.
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Affiliation(s)
- Matt Guest
- Department of Chemistry, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, ON, L2S 3A1, Canada
| | - Richard Le Sueur
- Department of Chemistry, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, ON, L2S 3A1, Canada
| | - Melanie Pilkington
- Department of Chemistry, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, ON, L2S 3A1, Canada
| | - Travis Dudding
- Department of Chemistry, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, ON, L2S 3A1, Canada
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Mir R, Rowshanpour R, Dempsey K, Pilkington M, Dudding T. Selective Aerobic Oxidation of Benzylic Alcohols Catalyzed by a Dicyclopropenylidene-Ag(I) Complex. J Org Chem 2019; 84:5726-5731. [PMID: 30896944 DOI: 10.1021/acs.joc.9b00624] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The unprecedented synthesis, single-crystal X-ray structure, and first catalytic application of a dicarbene-Ag(I) complex [Ag(BAC)2][CO2CF3] (BAC = bis(diisopropyl)aminocyclopropenylidene) is reported. This novel complex provides a versatile catalytic platform for selective aerobic oxidation of benzylic alcohols to aldehyde or ketone products in high yields. Ease of experimental execution coupled with the use of abundant atmospheric molecular oxygen as an oxidant and low catalyst loading are inherit strengths of these oxidations.
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Affiliation(s)
- Roya Mir
- Department of Chemistry , Brock University , 1812 Sir Isaac Brock Way , St. Catharines , Ontario , Canada L2S 3A1
| | - Rozhin Rowshanpour
- Department of Chemistry , Brock University , 1812 Sir Isaac Brock Way , St. Catharines , Ontario , Canada L2S 3A1
| | - Katie Dempsey
- Department of Chemistry , Brock University , 1812 Sir Isaac Brock Way , St. Catharines , Ontario , Canada L2S 3A1
| | - Melanie Pilkington
- Department of Chemistry , Brock University , 1812 Sir Isaac Brock Way , St. Catharines , Ontario , Canada L2S 3A1
| | - Travis Dudding
- Department of Chemistry , Brock University , 1812 Sir Isaac Brock Way , St. Catharines , Ontario , Canada L2S 3A1
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