1
|
Freudenberg J, Bunz UHF. How to Stabilize Large Soluble (Hetero-)Acenes. J Am Chem Soc 2024; 146:16937-16949. [PMID: 38862130 PMCID: PMC11212629 DOI: 10.1021/jacs.4c03484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 05/16/2024] [Accepted: 05/16/2024] [Indexed: 06/13/2024]
Abstract
The higher acenes and azaacenes (>(aza)heptacenes) are fascinating, yet elusive materials. Their reactivity and sensitivity increases concomitantly with their size. In recent years, confinement techniques, that is isolation of acenes in matrices and on surfaces, has surpassed solution-based chemistry with respect to accessing the larger (hetero)acenes at the price of the accessibility of no more than a couple thousands of molecules. Isolating acenes in bulk quantities and in processable form is vital for applications in organic electronics as well as from a viewpoint from basic research. In this Perspective, we will discuss after a short historical outline their degradation pathways, and then will selectively highlight recent efforts in stabilizing soluble (aza)acenes.
Collapse
Affiliation(s)
- Jan Freudenberg
- Ruprecht-Karls-Universität
Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
| | - Uwe H. F. Bunz
- Ruprecht-Karls-Universität
Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
| |
Collapse
|
2
|
Stroia I, Moisă ME, Pop A, Legrand B, Hanganu A, Hădade ND, Grosu I. Planar Chiral p,p'-Terphenyl-Based Cyclophanes with Remarkable Enantiomer Stability: Synthesis, Theoretical Investigations, and Complexation Studies. J Org Chem 2023; 88:15647-15657. [PMID: 37910657 DOI: 10.1021/acs.joc.3c01631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2023]
Abstract
Design of conformationally stable compounds with planar chirality is a topic of great interest mainly because of their potential applications as enantioselective ligands or other functional materials. Herein, we present the design and synthesis of novel planar chiral cyclophanes, obtained by ortho, ortho″ anchoring of the p,p'-terphenyl unit, with bridges of different lengths and rigidities, along with their nuclear magnetic resonance, mass spectrometry, and X-ray characterizations. We investigated the influence of the structural particularities of the bridges over the stability of the enantiomers, by means of nuclear magnetic resonance and chiral high-performance liquid chromatography as well as by density functional theory calculations. We also demonstrated the ability of one of the cyclophanes to preferentially bind arginine with Ka > 110 M-1 (ΔG > -11 kJ mol-1) in acetonitrile solutions containig 10 % water, in the presence of other amino acids.
Collapse
Affiliation(s)
- Ioan Stroia
- Faculty of Chemistry and Chemical Engineering, Department of Chemistry, Babeş-Bolyai University, 11 Arany Janos Street, 400028 Cluj-Napoca, Romania
- Supramolecular Organic and Organometallic Chemistry Centre (SOOMCC), 11 Arany Janos Street, 400028 Cluj-Napoca, Romania
| | - Mădălina Elena Moisă
- Faculty of Chemistry and Chemical Engineering, Department of Chemistry, Babeş-Bolyai University, 11 Arany Janos Street, 400028 Cluj-Napoca, Romania
| | - Alexandra Pop
- Faculty of Chemistry and Chemical Engineering, Department of Chemistry, Babeş-Bolyai University, 11 Arany Janos Street, 400028 Cluj-Napoca, Romania
- Supramolecular Organic and Organometallic Chemistry Centre (SOOMCC), 11 Arany Janos Street, 400028 Cluj-Napoca, Romania
| | - Baptiste Legrand
- Institut des Biomolécules Max Mousseron, IBMM, University of Montpellier, ENSCM, CNRS, 15 Avenue Charles Flahault BP 14 491, 34093 Montpellier Cedex 5, France
| | - Anamaria Hanganu
- Research Centre of Applied Organic Chemistry, Department of Organic Chemistry, Biochemistry and Catalysis, Faculty of Chemistry, University of Bucharest, 050663 Bucharest, Romania
- "C. D. Nenitzescu" Institute of Organic and Supramolecular Chemistry of the Romanian Academy, 060023 Bucharest, Romania
| | - Niculina Daniela Hădade
- Faculty of Chemistry and Chemical Engineering, Department of Chemistry, Babeş-Bolyai University, 11 Arany Janos Street, 400028 Cluj-Napoca, Romania
- Supramolecular Organic and Organometallic Chemistry Centre (SOOMCC), 11 Arany Janos Street, 400028 Cluj-Napoca, Romania
| | - Ion Grosu
- Faculty of Chemistry and Chemical Engineering, Department of Chemistry, Babeş-Bolyai University, 11 Arany Janos Street, 400028 Cluj-Napoca, Romania
- Supramolecular Organic and Organometallic Chemistry Centre (SOOMCC), 11 Arany Janos Street, 400028 Cluj-Napoca, Romania
| |
Collapse
|
3
|
Stroia I, Moraru IT, Miclăuş M, Grosu I, Lar C, Grosu IG, Terec A. Solid-State and Theoretical Investigations of Some Banister-Type Macrocycles with 2,2'-Aldoxime-1,1'-Biphenyl Units. Front Chem 2021; 9:750418. [PMID: 34692645 PMCID: PMC8527037 DOI: 10.3389/fchem.2021.750418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 09/20/2021] [Indexed: 11/17/2022] Open
Abstract
In the context of helical chirality, bridging of biphenyl units leads to banister-type compounds and the stability of the resulted atropisomers may increase dramatically if suitable changes are performed in the linker unit that coils around the biphenyl moiety. A rigorous density functional theory (DFT) study was conducted for macrocycles containing rigid oxime ether segments connected to the biphenyl backbone in order to determine how the rotation barriers are influenced by the presence of either a flexible oligoethyleneoxide or a more rigid m–xylylene component in the macrocycle. The calculated values for the racemization barrier were in good agreement with those obtained experimentally and confirm the benefit of introducing a more rigid unit in the macrocycle on the stability of atropisomers. Solid-state data were obtained and computed data were used to assess the contribution brought by supramolecular associations observed in the lattice to the stabilization of the crystal structure. Beside introducing rigidity in the linker, complexation of flexible macrocycles with alkali metal ions is also contributing to the stability of atropisomers, leading to values for the racemization barrier matching that of the rigid macrocycle. Using diethylammonium cation as guest for the macrocycle, a spectacular increase in the barrier to rotation was observed for the resulted pseudo[2]rotaxane.
Collapse
Affiliation(s)
- Ioan Stroia
- Department of Chemistry and SOOMCC, Faculty of Chemistry and Chemical Engineering, Babes-Bolyai University, Cluj-Napoca, Romania
| | - Ionuţ-Tudor Moraru
- Faculty of Chemistry and Chemical Engineering, Metalomica Research Centre, Babes-Bolyai University, Cluj-Napoca, Romania
| | - Maria Miclăuş
- National Institute for Research and Development of Isotopic and Molecular Technologies, Cluj-Napoca, Romania
| | - Ion Grosu
- Department of Chemistry and SOOMCC, Faculty of Chemistry and Chemical Engineering, Babes-Bolyai University, Cluj-Napoca, Romania
| | - Claudia Lar
- National Institute for Research and Development of Isotopic and Molecular Technologies, Cluj-Napoca, Romania
| | - Ioana Georgeta Grosu
- National Institute for Research and Development of Isotopic and Molecular Technologies, Cluj-Napoca, Romania
| | - Anamaria Terec
- Department of Chemistry and SOOMCC, Faculty of Chemistry and Chemical Engineering, Babes-Bolyai University, Cluj-Napoca, Romania
| |
Collapse
|