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Krückel T, Schauerte S, Ke J, Schlottmann M, Bausch S, Chen X, Räuber C, Almeida Silva ID, Wiegand T, Albrecht M. 7Li NMR Spectroscopy: A Tool for Determining Dimerization Constants and Averaged Dimerization Constants of the Monomer/Dimer Equilibrium of Hierarchical Helicates. Chemistry 2024; 30:e202400387. [PMID: 38451207 DOI: 10.1002/chem.202400387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 03/07/2024] [Accepted: 03/25/2024] [Indexed: 03/08/2024]
Abstract
7Li nuclear magnetic resonance (NMR) spectroscopy is an ideal tool to study hierarchically assembled helicates of the form Li[Li3L6Ti2]. Internally bound and external lithium ions can be well distinguished by solution- or solid-state NMR spectroscopy and dimerization constants of the monomer/dimer equilibrium can be easily determined in solution. Averaged dimerization constants can be estimated in case of statistical mixtures of helicates formed from mixtures of ligands.
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Affiliation(s)
- Tobias Krückel
- Institut für Organische Chemie, RWTH Aachen University, Landoltweg 1, D-52074, Aachen, Germany
| | - Steffen Schauerte
- Institut für Organische Chemie, RWTH Aachen University, Landoltweg 1, D-52074, Aachen, Germany
| | - Jinbo Ke
- Institut für Organische Chemie, RWTH Aachen University, Landoltweg 1, D-52074, Aachen, Germany
| | - Marcel Schlottmann
- Institut für Organische Chemie, RWTH Aachen University, Landoltweg 1, D-52074, Aachen, Germany
| | - Sandra Bausch
- Institut für Organische Chemie, RWTH Aachen University, Landoltweg 1, D-52074, Aachen, Germany
| | - Xiaofei Chen
- Institut für Organische Chemie, RWTH Aachen University, Landoltweg 1, D-52074, Aachen, Germany
| | - Christoph Räuber
- Institut für Organische Chemie, RWTH Aachen University, Landoltweg 1, D-52074, Aachen, Germany
| | | | - Thomas Wiegand
- Max-Planck Institut für chemische Energiekonversion, Stiftstr. 34-36, D-45470, Mülheim/Ruhr, Germany
- Institut für Technische und Makromolekulare Chemie, RWTH Aachen University, Worringerweg 2, D-52074, Aachen, Germany
| | - Markus Albrecht
- Institut für Organische Chemie, RWTH Aachen University, Landoltweg 1, D-52074, Aachen, Germany
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Albrecht M. The Monomer-Dimer Equilibrium of Triscatechol Titanium(IV)-Based Hierarchical Helicates as a Tool for the Development of Molecular Balances and Molecular Switches. Acc Chem Res 2023; 56:3271-3281. [PMID: 37955356 DOI: 10.1021/acs.accounts.3c00525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2023]
Abstract
ConspectusHierarchical helicates are formed by noncovalent connection of two or more monomeric metal complex units, e.g., by bridging metal cations. A unique kind of hierarchical helicate is obtained from 3-carbonyl substituted catechol ligands with titanium(IV) ions in the presence of lithium cations. This kind of supramolecular complex shows in solution a "monomer-dimer" equilibrium. There are different possibilities (solvent, countercation, substituents at carbonyl unit, etc.) to shift this equilibrium to either the monomer or the dimer side. Thus, the lithium-bridged catecholate-based hierarchical helicates resemble a molecular switch. In this Account, different aspects are discussed of how this unique behavior of the dimeric titanium catecholates can be used for application.Thorough investigation of the energetics of the monomer-dimer equilibrium leads to a deeper understanding of the thermodynamic and kinetic effects of the dimerization (or dissociation) process. In this context, even weak interaction of substituents in the periphery of the complexes can be observed. Hereby on the one hand, solvent effects have an important influence and can be easily evaluated. The thorough understanding of the behavior of the monomer-dimer equilibrium allows one to develop some novel applications. In this respect, the use of the hierarchical helicate-based switch as a platform for reaction control and catalysis is described. Decent enantioselectivities up to ee = 58% can be found in Diels-Alder reactions in the periphery of the dimers, while switching to the monomer as a reaction platform still allows the cycloaddition reaction but turns the selectivity off. Additionally, it is described that catalytically important units can be introduced and hydrogenation reactions as well as Michael-type reactions are catalyzed at the helicates.Covalent connection of two catechol ester units leads to classical helicates. Depending on the alkaline metal cation, those can be switched from a compressed to an expanded form or vice versa. Hereby the monomer-dimer equilibrium is transformed into a structural switch. The switching process can be initiated by removal or addition of lithium cations (e.g., by addition of [2.1.1]cryptand). Alternative switching possibilities are based in the case of glycol bridged helicates on cation translocation isomerism and with thioester derivatives it occurs spontaneously in DMSO. Introduction of chiral tethers results in a three state switch allowing expansion/compression as well as switching of the helicity.
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Affiliation(s)
- Markus Albrecht
- Institut für Organische Chemie, RWTH Aachen University, Landoltweg 1, D-52074 Aachen, Germany
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3
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Ahmadi M, Sprenger C, Pareras G, Poater A, Seiffert S. Self-organization of metallo-supramolecular polymer networks by free formation of pyridine-phenanthroline heteroleptic complexes. SOFT MATTER 2023; 19:8112-8123. [PMID: 37846598 DOI: 10.1039/d3sm01136d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2023]
Abstract
Nature employs spontaneous self-organization of supramolecular bonds to create complex matter capable of adaptation and self-healing. Accordingly, the self-sorting of unlike ligands towards a cooperative heteroleptic complex or narcistic homoleptic association in a mixed ligand system is frequently employed to form interchangeable stimuli-responsive complex geometries with a wide range of applications. This notion is however just rarely employed in the organization of polymer networks. In this paper, we report the free-formation of heteroleptic complexes between tetra-am poly(ethylene glycol) (tetraPEG) precursors functionalized either with pyridine (tetraPy) or phenanthroline (tetraEPhen). Among a wide range of studied metal ions, tetraPy could form a network only in combination with Pd2+, presumably with a square-planar geometry, highlighting the importance of complex strength and stability in forming gels with monodentate ligands. Also, mixed networks with tetraEPhen form only in combination with Pd2+ and Fe2+, with strengths surpassing those of individual components and stabilities incomparable to those of parent networks, indicative of heteroleptic complexation. Extensive rheological, UV-vis, and DFT simulation studies revealed the coexistence of different coordination geometries, with an octahedral arrangement prevailing in the presence of Fe2+ and a square-planar geometry in the presence of Pd2+. Therefore, this study offers new opportunities for the development of stimuli-responsive topology-switching polymer networks.
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Affiliation(s)
- Mostafa Ahmadi
- Department of Chemistry, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, D-55128 Mainz, Germany.
| | - Cora Sprenger
- Department of Chemistry, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, D-55128 Mainz, Germany.
| | - Gerard Pareras
- Institut de Química Computacional i Catàlisi, Departament de Química, Universitat de Girona, c/Ma Aurèlia Capmany 69, 17003 Girona, Catalonia, Spain
- Departament de Química, Universitat Autònoma de Barcelona, Bellaterra, Catalonia 08193, Spain
| | - Albert Poater
- Institut de Química Computacional i Catàlisi, Departament de Química, Universitat de Girona, c/Ma Aurèlia Capmany 69, 17003 Girona, Catalonia, Spain
| | - Sebastian Seiffert
- Department of Chemistry, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, D-55128 Mainz, Germany.
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Yin F, Liu Z, Yang J, Zhou LP, Tian CB, Sun QF. Self-Assembly of Triple-Stranded Lanthanide Molecular Quasi-Lantern Containing 2,2'-Bipyridine Receptor: Luminescence Sensing and Magnetic Property. ACS OMEGA 2023; 8:24477-24484. [PMID: 37457487 PMCID: PMC10339439 DOI: 10.1021/acsomega.3c02419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 06/13/2023] [Indexed: 07/18/2023]
Abstract
Ln2L3-type supramolecular architectures have received significant attention recently due to their unique magnetism and optical properties. Herein, we report the triple-stranded Ln2L3-type lanthanide molecular quasi-lanterns, which are fabricated by the deprotonation self-assembly of a linear ligand featuring a β-diketone chelating claw and 2,2'-bipyridine (bpy) moiety with lanthanide ions (Ln = Eu3+ and Dy3+). The crystal structure analysis indicates that Eu3+ and Dy3+ ions are all coordinated by eight oxygen donors but in different coordination geometries. The eight oxygen donors in Eu2L3 and Dy2L3 are arranged in a square antiprism and triangular dodecahedron geometry, respectively. Taking into account the fact that the bpy moiety has a strong coordination affinity for transition metal ions, luminescence sensing toward Cu2+ ions has been demonstrated with Eu2L3, bearing a detection of limit as low as 2.84 ppb. The luminescence sensing behavior of Eu2L3 is ascribed to the formation host-guest complex between Eu2L3 and Cu2+ ions with a 1:2 binding ratio. Dynamic AC susceptibility measurements for Dy2L3 reveal the relaxation of magnetization in it. This work provides a potential way for design and fabrication of lanthanide-based molecular materials with functions endowed by the ligands.
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Affiliation(s)
- Fan Yin
- College
of Chemistry, Fuzhou University, Fuzhou 350108, People’s Republic of China
- Fujian
College, University of Chinese Academy of
Sciences, Fuzhou 350002, People’s Republic
of China
| | - Zhi Liu
- College
of Chemistry, Fuzhou University, Fuzhou 350108, People’s Republic of China
- Fujian
College, University of Chinese Academy of
Sciences, Fuzhou 350002, People’s Republic
of China
| | - Jian Yang
- Fujian
College, University of Chinese Academy of
Sciences, Fuzhou 350002, People’s Republic
of China
| | - Li-Peng Zhou
- Fujian
College, University of Chinese Academy of
Sciences, Fuzhou 350002, People’s Republic
of China
| | - Chong-Bin Tian
- College
of Chemistry, Fuzhou University, Fuzhou 350108, People’s Republic of China
- Fujian
College, University of Chinese Academy of
Sciences, Fuzhou 350002, People’s Republic
of China
| | - Qing-Fu Sun
- College
of Chemistry, Fuzhou University, Fuzhou 350108, People’s Republic of China
- Fujian
College, University of Chinese Academy of
Sciences, Fuzhou 350002, People’s Republic
of China
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Nguyen T, Tran NM, Park IH, Yoo H. Heteroleptic Triple-Stranded Metallosupramolecules with Hydrophobic Inner Voids. ACS OMEGA 2022; 7:13067-13074. [PMID: 35474782 PMCID: PMC9026104 DOI: 10.1021/acsomega.2c00447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 03/25/2022] [Indexed: 06/14/2023]
Abstract
The systematic combination of well-defined coordination spheres and multiple types of ligands (heteroleptic) can lead to the generation of hierarchical metallosupramolecules with a high level of complexity and functionality. In particular, a specific multilevel coordination-driven assembly through the initiate generation of multinuclear clusters can form unique heteroleptic multiple-stranded supramolecular complexes. Herein, we report novel triple-stranded nickel-based supramolecules constructed from two different ditopic ligands ([1,1':3',1''-terphenyl]-4,4''-dicarboxylate (TP) and 2,6-pyridinedicarboxylate (PDA)) and a nickel precursor. The solid-state structures of the as-synthesized supramolecules revealed that three PDA ligands are employed to fabricate a tetranuclear ({Ni4}) cluster, and two {Ni4} clusters are assembled to form the final triple-stranded metallosupramolecules by three TP ligands. The bridging TP ligands also provide large inner voids with highly hydrophobic environments. Structural investigation of the generated complexes provided a deeper understanding of the aspects driving the formation of heteroleptic supramolecules, which is crucial for the design of multiple-strands with desired morphologies and functionalities.
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Affiliation(s)
- Thanh
Nhan Nguyen
- Department
of Materials Science and Chemical Engineering, Hanyang University, Ansan, Gyeonggi-do 15588, Republic of Korea
| | - Ngoc Minh Tran
- Department
of Materials Science and Chemical Engineering, Hanyang University, Ansan, Gyeonggi-do 15588, Republic of Korea
| | - In-Hyeok Park
- Graduate
School of Analytical Science and Technology (GRAST), Chungnam National University, Daejeon 34134, Republic of Korea
| | - Hyojong Yoo
- Department
of Materials Science and Chemical Engineering, Hanyang University, Ansan, Gyeonggi-do 15588, Republic of Korea
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Lisboa LS, Riisom M, Vasdev RAS, Jamieson SMF, Wright LJ, Hartinger CG, Crowley JD. Cavity-Containing [Fe 2L 3] 4+ Helicates: An Examination of Host-Guest Chemistry and Cytotoxicity. Front Chem 2021; 9:697684. [PMID: 34307299 PMCID: PMC8292671 DOI: 10.3389/fchem.2021.697684] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 06/16/2021] [Indexed: 02/04/2023] Open
Abstract
Two new di(2,2′-bipyridine) ligands, 2,6-bis([2,2′-bipyridin]-5-ylethynyl)pyridine (L1) and bis(4-([2,2′-bipyridin]-5-ylethynyl)phenyl)methane (L2) were synthesized and used to generate two metallosupramolecular [Fe2(L)3](BF4)4 cylinders. The ligands and cylinders were characterized using elemental analysis, electrospray ionization mass spectrometry, UV-vis, 1H-, 13C and DOSY nuclear magnetic resonance (NMR) spectroscopies. The molecular structures of the [Fe2(L)3](BF4)4 cylinders were confirmed using X-ray crystallography. Both the [Fe2(L1)3](BF4)4 and [Fe2(L2)3](BF4)4 complexes crystallized as racemic (rac) mixtures of the ΔΔ (P) and ΛΛ (M) helicates. However, 1H NMR spectra showed that in solution the larger [Fe2(L2)3](BF4)4 was a mixture of the rac-ΔΔ/ΛΛ and meso-ΔΛ isomers. The host-guest chemistry of the helicates, which both feature a central cavity, was examined with several small drug molecules. However, none of the potential guests were found to bind within the helicates. In vitro cytotoxicity assays demonstrated that both helicates were active against four cancer cell lines. The smaller [Fe2(L1)3](BF4)4 system displayed low μM activity against the HCT116 (IC50 = 7.1 ± 0.5 μM) and NCI-H460 (IC50 = 4.9 ± 0.4 μM) cancer cells. While the antiproliferative effects against all the cell lines examined were less than the well-known anticancer drug cisplatin, their modes of action would be expected to be very different.
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Affiliation(s)
- Lynn S Lisboa
- Department of Chemistry, University of Otago, Dunedin, New Zealand
| | - Mie Riisom
- School of Chemical Sciences, University of Auckland, Auckland, New Zealand.,Auckland Cancer Society Research Centre, University of Auckland, Auckland, New Zealand
| | - Roan A S Vasdev
- Department of Chemistry, University of Otago, Dunedin, New Zealand
| | - Stephen M F Jamieson
- Auckland Cancer Society Research Centre, University of Auckland, Auckland, New Zealand
| | - L James Wright
- School of Chemical Sciences, University of Auckland, Auckland, New Zealand
| | | | - James D Crowley
- Department of Chemistry, University of Otago, Dunedin, New Zealand
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Ahmadi M, Seiffert S. Direct Evidence of Heteroleptic Complexation in the Macroscopic Dynamics of Metallo-supramolecular Polymer Networks. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c00551] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mostafa Ahmadi
- Department of Chemistry, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, D-55128 Mainz, Germany
| | - Sebastian Seiffert
- Department of Chemistry, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, D-55128 Mainz, Germany
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