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Hollstein S, von Delius M. The Dynamic Chemistry of Orthoesters and Trialkoxysilanes: Making Supramolecular Hosts Adaptive, Fluxional, and Degradable. Acc Chem Res 2024. [PMID: 38286767 PMCID: PMC10882968 DOI: 10.1021/acs.accounts.3c00738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2024]
Abstract
ConspectusThe encapsulation of ions into macro(bi)cyclic hosts lies at the core of supramolecular chemistry. While chemically inert hosts such as crown ethers (synthesis) and cyclodextrins (Febreze) have enabled real-world applications, there is a wider and accelerating trend toward functional molecules and materials that are stimuli-responsive, degradable, or recyclable. To endow supramolecular hosts with these properties, a deviation from ether C-O bonds is required, and functional groups that engage in equilibrium reactions under relatively mild conditions are needed.In this Account, we describe our group's work on supramolecular hosts that comprise orthoester and trialkoxysilane bridgeheads. In their simplest structural realization, these compounds resemble both Cram's crown ethers (macrocycles with oxygen donor atoms) and Lehn's cryptands (macrobicycles with 3-fold symmetry). It is therefore not surprising that these new hosts were found to have a natural propensity to bind cations relatively strongly. In recent work, we were also able to create anion-binding hosts by placing disubstituted urea motifs at the center of the tripodal architecture. Structural modifications of either the terminal substituents (e.g., H vs CH3 on the bridgehead), the diol (e.g., chiral), or the bridgehead atom itself (Si vs C) were found to have profound implications on the guest-binding properties.What makes orthoester/trialkoxysilane hosts truly unique is their dynamic covalent chemistry. The ability to conduct exchange reactions with alcohols at the bridgehead carbon or silicon atom is first and foremost an opportunity to develop highly efficient syntheses. Indeed, all hosts presented in this Account were prepared via templated self-assembly in yields of up to 90%. This efficiency is remarkable because the macrobicyclic architecture is established in one single step from at least five components. A second opportunity presented by dynamic bridgeheads is that suitable mixtures of orthoester hosts or their subcomponents can be adaptive, i.e. they respond to the presence of guests such that the addition of a certain guest can dictate the formation of a preferred host. In an extreme example of dynamic adaptivity, we found that ammonium ions can fulfill the dual role of catalyst for orthoester exchange and cationic template for efficient host formation, representing an unprecedented example of a fluxional supramolecular complex. The third implication of dynamic bridgeheads is due to the reaction of orthoesters and trialkoxysilanes with water instead of alcohols. We describe in detail how the hydrolysis rate differs strongly between O,O,O-orthoesters, S,S,S-trithioorthoesters, and trialkoxysilanes and how it is tunable by the choice of substituents and pH.We expect that the fundamental insights into exchange and degradation kinetics described in this Account will be useful far beyond supramolecular chemistry.
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Affiliation(s)
- Selina Hollstein
- Institute of Organic Chemistry, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Max von Delius
- Institute of Organic Chemistry, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
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Hollstein S, Shyshov O, Hanževački M, Zhao J, Rudolf T, Jäger CM, von Delius M. Dynamic Covalent Self-Assembly of Chloride- and Ion-Pair-Templated Cryptates. Angew Chem Int Ed Engl 2022; 61:e202201831. [PMID: 35384202 PMCID: PMC9400851 DOI: 10.1002/anie.202201831] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Indexed: 12/17/2022]
Abstract
While supramolecular hosts capable of binding and transporting anions and ion pairs are now widely available, self-assembled architectures are still rare, even though they offer an inherent mechanism for the release of the guest ion(s). In this work, we report the dynamic covalent self-assembly of tripodal, urea-based anion cryptates that are held together by two orthoester bridgeheads. These hosts exhibit affinity for anions such as Cl- , Br- or I- in the moderate range that is typically advantageous for applications in membrane transport. In unprecedented experiments, we were able to dissociate the Cs⋅Cl ion pair by simultaneously assembling suitably sized orthoester hosts around the Cs+ and the Cl- ion.
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Affiliation(s)
- Selina Hollstein
- Institute of Organic ChemistryUlm UniversityAlbert-Einstein-Allee 1189081UlmGermany
| | - Oleksandr Shyshov
- Institute of Organic ChemistryUlm UniversityAlbert-Einstein-Allee 1189081UlmGermany
| | - Marko Hanževački
- Department of Chemical and Environmental EngineeringUniversity of Nottingham University ParkNottinghamNG7 2RDUK
| | - Jie Zhao
- Institute of Organic ChemistryUlm UniversityAlbert-Einstein-Allee 1189081UlmGermany
| | - Tamara Rudolf
- Institute of Organic ChemistryUlm UniversityAlbert-Einstein-Allee 1189081UlmGermany
| | - Christof M. Jäger
- Department of Chemical and Environmental EngineeringUniversity of Nottingham University ParkNottinghamNG7 2RDUK
| | - Max von Delius
- Institute of Organic ChemistryUlm UniversityAlbert-Einstein-Allee 1189081UlmGermany
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3
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Hollstein S, Shyshov O, Hanževački M, Zhao J, Rudolf T, Jäger CM, Delius M. Dynamisch kovalente Selbstassemblierung von Chlorid‐ und Ionenpaar‐templierten Kryptaten. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202201831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Selina Hollstein
- Institut für Organische Chemie Universität Ulm Albert-Einstein-Allee 11 89081 Ulm Deutschland
| | - Oleksandr Shyshov
- Institut für Organische Chemie Universität Ulm Albert-Einstein-Allee 11 89081 Ulm Deutschland
| | - Marko Hanževački
- Department of Chemical and Environmental Engineering University of Nottingham University Park Nottingham NG7 2RD Großbritannien
| | - Jie Zhao
- Institut für Organische Chemie Universität Ulm Albert-Einstein-Allee 11 89081 Ulm Deutschland
| | - Tamara Rudolf
- Institut für Organische Chemie Universität Ulm Albert-Einstein-Allee 11 89081 Ulm Deutschland
| | - Christof M. Jäger
- Department of Chemical and Environmental Engineering University of Nottingham University Park Nottingham NG7 2RD Großbritannien
| | - Max Delius
- Institut für Organische Chemie Universität Ulm Albert-Einstein-Allee 11 89081 Ulm Deutschland
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4
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Parks FC, Sheetz EG, Stutsman SR, Lutolli A, Debnath S, Raghavachari K, Flood AH. Revealing the Hidden Costs of Organization in Host-Guest Chemistry Using Chloride-Binding Foldamers and Their Solvent Dependence. J Am Chem Soc 2022; 144:1274-1287. [PMID: 35015538 DOI: 10.1021/jacs.1c10758] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Preorganization is a key concept in supramolecular chemistry. Preorganized receptors enhance binding by minimizing the organization costs associated with adopting the conformation needed to orient the binding sites toward the guest. Conversely, poorly organized receptors show affinities below what is possible based on the potential of their specific binding interactions. Despite the fact that the organization energy is paid each time like a tax, its value has never been measured directly, though many compounds have been developed to measure its effects. We present a method to quantify the hidden costs of receptor organization by independently measuring the contribution it makes to chloride complexation by a flexible foldameric receptor. This method uses folding energy to approximate organization energy and relies on measurement of the coil-helix equilibrium as a function of solvent. We also rely on the finding, established with rigid receptors, that affinity is inversely related to the solvent dielectric and expect the same for the foldamer's helically organized state. Increasing solvent polarity across nine dichloromethane-acetonitrile mixtures we see an unusual V-shape in affinity (decrease then increase). Quantitatively, this shape arises from weakened hydrogen-bonding interactions with solvent polarity followed by solvent-driven folding into an organized helix. We confirm that dielectric screening impacts the stability of host-guest complexes of flexible foldamers just like rigid receptors. These results experimentally verify the canonical model of binding (affinity depends on the sum of organization and noncovalent interactions). The picture of how solvent impacts complex stability and conformational organization thereby helps lay the groundwork for de novo receptor design.
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Affiliation(s)
- Fred C Parks
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Edward G Sheetz
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Sydney R Stutsman
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Alketa Lutolli
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Sibali Debnath
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Krishnan Raghavachari
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Amar H Flood
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
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5
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Chen Q, Lei Y, Wu G, Li Q, Pan Y, Li H. Ultramacrocyclization in water via external templation. Chem Sci 2022; 13:798-803. [PMID: 35173945 PMCID: PMC8768864 DOI: 10.1039/d1sc06236k] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 12/19/2021] [Indexed: 12/04/2022] Open
Abstract
Condensing a dihydrazide and each of a series of cationic bisaldehyde compounds bearing polymethylene chains in weakly acidic water produces either a macrocycle in a [1 + 1] manner or its dimer namely a [2]catenane, or their mixture. The product distribution is determined by the length of the bisaldehydes. Addition of cucurbit[8]uril (CB[8]) drives the catenane/macrocycle equilibria to the side of macrocycles, by forming ring-in-ring complexes with the latter. When the polymethylene unit of the bisaldehyde is replaced with a more rigid p-xylene linker, its self-assembly with the dihydrazide leads to quantitative formation of a [2]catenane. Upon addition of CB[8], the [2]catenane is transformed into an ultra-large macrocycle condensed in a [2 + 2] manner, which is encircled by two CB[8] rings. The framework of this macrocycle contains one hundred and two atoms, whose synthesis would be a formidable task without the external template CB[8]. Removal of CB[8] with a competitive guest leads to recovery of the [2]catenane.
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Affiliation(s)
- Qiong Chen
- Department of Chemistry Institution, Zhejiang University Hangzhou 310027 China
| | - Ye Lei
- Department of Chemistry Institution, Zhejiang University Hangzhou 310027 China
| | - Guangcheng Wu
- Department of Chemistry Institution, Zhejiang University Hangzhou 310027 China
| | - Qing Li
- Key Laboratory of Macrocyclic and Supramolecular Chemistry, Guizhou University Guiyang 550025 China
| | - Yuanjiang Pan
- Department of Chemistry Institution, Zhejiang University Hangzhou 310027 China
| | - Hao Li
- Department of Chemistry Institution, Zhejiang University Hangzhou 310027 China
- ZJU-Hangzhou Global Scientific and Technological Innovation Center Hangzhou 310027 China
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Alabugin IV, Kuhn L, Medvedev MG, Krivoshchapov NV, Vil' VA, Yaremenko IA, Mehaffy P, Yarie M, Terent'ev AO, Zolfigol MA. Stereoelectronic power of oxygen in control of chemical reactivity: the anomeric effect is not alone. Chem Soc Rev 2021; 50:10253-10345. [PMID: 34263287 DOI: 10.1039/d1cs00386k] [Citation(s) in RCA: 70] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Although carbon is the central element of organic chemistry, oxygen is the central element of stereoelectronic control in organic chemistry. Generally, a molecule with a C-O bond has both a strong donor (a lone pair) and a strong acceptor (e.g., a σ*C-O orbital), a combination that provides opportunities to influence chemical transformations at both ends of the electron demand spectrum. Oxygen is a stereoelectronic chameleon that adapts to the varying situations in radical, cationic, anionic, and metal-mediated transformations. Arguably, the most historically important stereoelectronic effect is the anomeric effect (AE), i.e., the axial preference of acceptor groups at the anomeric position of sugars. Although AE is generally attributed to hyperconjugative interactions of σ-acceptors with a lone pair at oxygen (negative hyperconjugation), recent literature reports suggested alternative explanations. In this context, it is timely to evaluate the fundamental connections between the AE and a broad variety of O-functional groups. Such connections illustrate the general role of hyperconjugation with oxygen lone pairs in reactivity. Lessons from the AE can be used as the conceptual framework for organizing disjointed observations into a logical body of knowledge. In contrast, neglect of hyperconjugation can be deeply misleading as it removes the stereoelectronic cornerstone on which, as we show in this review, the chemistry of organic oxygen functionalities is largely based. As negative hyperconjugation releases the "underutilized" stereoelectronic power of unshared electrons (the lone pairs) for the stabilization of a developing positive charge, the role of orbital interactions increases when the electronic demand is high and molecules distort from their equilibrium geometries. From this perspective, hyperconjugative anomeric interactions play a unique role in guiding reaction design. In this manuscript, we discuss the reactivity of organic O-functionalities, outline variations in the possible hyperconjugative patterns, and showcase the vast implications of AE for the structure and reactivity. On our journey through a variety of O-containing organic functional groups, from textbook to exotic, we will illustrate how this knowledge can predict chemical reactivity and unlock new useful synthetic transformations.
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Affiliation(s)
- Igor V Alabugin
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306, USA.
| | - Leah Kuhn
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306, USA.
| | - Michael G Medvedev
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky prosp., 119991 Moscow, Russian Federation.,A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 Vavilova St., 119991 Moscow, Russian Federation
| | - Nikolai V Krivoshchapov
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky prosp., 119991 Moscow, Russian Federation.,Lomonosov Moscow State University, Leninskie Gory 1 (3), Moscow, 119991, Russian Federation
| | - Vera A Vil'
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky prosp., 119991 Moscow, Russian Federation
| | - Ivan A Yaremenko
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky prosp., 119991 Moscow, Russian Federation
| | - Patricia Mehaffy
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306, USA.
| | - Meysam Yarie
- Department of Organic Chemistry, Faculty of Chemistry, Bu-Ali Sina University, Hamedan 65167, Iran
| | - Alexander O Terent'ev
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky prosp., 119991 Moscow, Russian Federation
| | - Mohammad Ali Zolfigol
- Department of Organic Chemistry, Faculty of Chemistry, Bu-Ali Sina University, Hamedan 65167, Iran
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Chen Y, Wu G, Chen B, Qu H, Jiao T, Li Y, Ge C, Zhang C, Liang L, Zeng X, Cao X, Wang Q, Li H. Self‐Assembly of a Purely Covalent Cage with Homochirality by Imine Formation in Water. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202106428] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Yixin Chen
- Department of Chemistry Zhejiang University Hangzhou 310027 China
| | - Guangcheng Wu
- Department of Chemistry Zhejiang University Hangzhou 310027 China
| | - Binbin Chen
- Department of Chemistry Zhejiang University Hangzhou 310027 China
| | - Hang Qu
- State Key Laboratory of Physical Chemistry of Solid Surfaces iChEM and College of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 China
| | - Tianyu Jiao
- Department of Chemistry Zhejiang University Hangzhou 310027 China
| | - Yintao Li
- Department of Chemistry Zhejiang University Hangzhou 310027 China
| | - Chenqi Ge
- Department of Chemistry Zhejiang University Hangzhou 310027 China
| | - Chi Zhang
- Department of Chemistry Zhejiang University Hangzhou 310027 China
| | - Lixin Liang
- Department of Chemistry Zhejiang University Hangzhou 310027 China
| | - Xiuqiong Zeng
- Department of Chemistry Zhejiang University Hangzhou 310027 China
| | - Xiaoyu Cao
- State Key Laboratory of Physical Chemistry of Solid Surfaces iChEM and College of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 China
| | - Qi Wang
- Department of Chemistry Zhejiang University Hangzhou 310027 China
| | - Hao Li
- Department of Chemistry Zhejiang University Hangzhou 310027 China
- ZJU-Hangzhou Global Scientific and Technological Innovation Center Hangzhou 311215 China
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8
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Chen Y, Wu G, Chen B, Qu H, Jiao T, Li Y, Ge C, Zhang C, Liang L, Zeng X, Cao X, Wang Q, Li H. Self-Assembly of a Purely Covalent Cage with Homochirality by Imine Formation in Water. Angew Chem Int Ed Engl 2021; 60:18815-18820. [PMID: 34129262 DOI: 10.1002/anie.202106428] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 06/04/2021] [Indexed: 11/11/2022]
Abstract
Self-assembly of host molecules in aqueous media via metal-ligand coordination is well developed. However, the preparation of purely covalent counterparts in water has remained a formidable task. An anionic tetrahedron cage was successfully self-assembled in a [4+4] manner by condensing a trisamine and a trisformyl in water. Even although each individual imine bond is rather labile and apt to hydrolyze in water, the tetrahedron is remarkably stable or inert due to multivalence. The tetrahedral cages, as well as its neutral counterparts dissolved in organic solvent, have homochirality, namely that their four propeller-shaped trisformyl residues adopt the same rotational conformation. The cage is able to take advantage of hydrophobic effect to accommodate a variety of guest molecules in water. When a chiral guest was recognized, the formation of one enantiomer of the cage became more favored relative to the other. As a consequence, the cage could be produced in an enantioselective manner. The tetrahedron is able to maintain its chirality after removal of the chiral guest-probably on account of the cooperative occurrence of intramolecular forces that restrict the intramolecular flipping of phenyl units in the cage framework.
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Affiliation(s)
- Yixin Chen
- Department of Chemistry, Zhejiang University, Hangzhou, 310027, China
| | - Guangcheng Wu
- Department of Chemistry, Zhejiang University, Hangzhou, 310027, China
| | - Binbin Chen
- Department of Chemistry, Zhejiang University, Hangzhou, 310027, China
| | - Hang Qu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM and College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Tianyu Jiao
- Department of Chemistry, Zhejiang University, Hangzhou, 310027, China
| | - Yintao Li
- Department of Chemistry, Zhejiang University, Hangzhou, 310027, China
| | - Chenqi Ge
- Department of Chemistry, Zhejiang University, Hangzhou, 310027, China
| | - Chi Zhang
- Department of Chemistry, Zhejiang University, Hangzhou, 310027, China
| | - Lixin Liang
- Department of Chemistry, Zhejiang University, Hangzhou, 310027, China
| | - Xiuqiong Zeng
- Department of Chemistry, Zhejiang University, Hangzhou, 310027, China
| | - Xiaoyu Cao
- State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM and College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Qi Wang
- Department of Chemistry, Zhejiang University, Hangzhou, 310027, China
| | - Hao Li
- Department of Chemistry, Zhejiang University, Hangzhou, 310027, China.,ZJU-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou, 311215, China
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9
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Shang J, Gong H, Zhang Q, Cui Z, Li S, Lv P, Pan T, Ge Y, Qi Z. The dynamic covalent reaction based on diselenide-containing crown ether irradiated by visible light. CHINESE CHEM LETT 2021. [DOI: 10.1016/j.cclet.2020.11.043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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10
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Löw H, Mena-Osteritz E, Mullen KM, Jäger CM, von Delius M. Self-Assembly, Adaptive Response, and in,out-Stereoisomerism of Large Orthoformate Cryptands. Chempluschem 2020; 85:1008-1012. [PMID: 32347636 DOI: 10.1002/cplu.202000254] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 04/16/2020] [Indexed: 12/19/2022]
Abstract
We report on triethylene glycol-based orthoformate cryptands, which adapt their bridgehead configurations in response to metal templates and intramolecular hydrogen bonding in a complex manner. In contrast to smaller 1.1.1-orthoformate cryptands, the inversion from out,out-2.2.2 to in,in-2.2.2 occurs spontaneously by thermal homeomorphic isomerization, i. e., without bond breakage. The global thermodynamic minimum of the entire network, which includes an unprecedented third isomer (in,out-2.2.2), could only be reached under conditions that facilitate dynamic covalent exchange. Both inversion processes were studied in detail, including DFT calculations and MD simulations, which were particularly helpful for explaining differences between equilibrium compositions in solvents chloroform and acetonitrile. Unexpectedly, the system could be driven to the in,out-2.2.2 state by using a metal template with a size mismatch with respect to the out,out-2.2.2 cage.
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Affiliation(s)
- Henrik Löw
- Institute of Organic Chemistry, University of Ulm, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Elena Mena-Osteritz
- Institute of Organic Chemistry, University of Ulm, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Kathleen M Mullen
- School of Chemistry and Physics, Queensland University of Technology, Brisbane, Queensland, 4001, Australia
| | - Christof M Jäger
- Department of Chemical and Environmental Engineering, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
| | - Max von Delius
- Institute of Organic Chemistry, University of Ulm, Albert-Einstein-Allee 11, 89081, Ulm, Germany
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Lauer JC, Pang Z, Janßen P, Rominger F, Kirschbaum T, Elstner M, Mastalerz M. Host-Guest Chemistry of Truncated Tetrahedral Imine Cages with Ammonium Ions. ChemistryOpen 2020; 9:183-190. [PMID: 32025463 PMCID: PMC6996569 DOI: 10.1002/open.201900357] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 01/10/2020] [Indexed: 01/29/2023] Open
Abstract
Three shape-persistent [4+4] imine cages with truncated tetrahedral geometry with different window sizes were studied as hosts for the encapsulation of tetra-n-alkylammonium salts of various bulkiness. In various solvents the cages behave differently. For instance, in dichloromethane the cage with smallest window size takes up NEt4+ but not NMe4+, which is in contrast to the two cages with larger windows hosting both ions. To find out the reason for this, kinetic experiments were carried out to determine the velocity of uptake but also to deduce the activation barriers for these processes. To support the experimental results, calculations for the guest uptakes have been performed by molecular mechanics' simulations. Finally, the complexation of pharmaceutical interested compounds, such as acetylcholine, muscarine or denatonium have been determined by NMR experiments.
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Affiliation(s)
- Jochen C. Lauer
- Organisch-Chemisches InstitutRuprecht-Karls-Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Ziwei Pang
- Institut für Physikalische Chemie Theoretische Chemische BiologieUniversität Karlsruhe Geb. 30.44Kaiserstr. 1276131KarlsruheGermany
| | - Paul Janßen
- Organisch-Chemisches InstitutRuprecht-Karls-Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Frank Rominger
- Organisch-Chemisches InstitutRuprecht-Karls-Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Tobias Kirschbaum
- Organisch-Chemisches InstitutRuprecht-Karls-Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Marcus Elstner
- Institut für Physikalische Chemie Theoretische Chemische BiologieUniversität Karlsruhe Geb. 30.44Kaiserstr. 1276131KarlsruheGermany
| | - Michael Mastalerz
- Organisch-Chemisches InstitutRuprecht-Karls-Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
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