1
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Song H, Kostrhunova H, Cervinka J, Macpherson J, Malina J, Rajan T, Phillips R, Postings M, Shepherd S, Zhang X, Brabec V, Rogers NJ, Scott P. Dicobalt(ii) helices kill colon cancer cells via enantiomer-specific mechanisms; DNA damage or microtubule disruption. Chem Sci 2024; 15:11029-11037. [PMID: 39027295 PMCID: PMC11253168 DOI: 10.1039/d4sc02541e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Accepted: 06/14/2024] [Indexed: 07/20/2024] Open
Abstract
Highly diastereoselective self-assembly reactions give both enantiomers (Λ and Δ) of anti-parallel triple-stranded bimetallic Co(ii) and Co(iii) cationic helices, without the need for resolution; the first such reaction for Co. The complexes are water soluble and stable, even in the case of Co(ii). Studies in a range of cancer and healthy cell lines indicate high activity and selectivity, and substantial differences between enantiomers. The oxidation state has little effect, and correspondingly, Co(iii) compounds are reduced to Co(ii) e.g. by glutathione. In HCT116 colon cancer cells the Λ enantiomer induces dose-dependent G2-M arrest in the cell cycle and disrupts microtubule architectures. This Co(ii) Λ enantiomer is ca. five times more potent than the isostructural Fe(ii) compound. Since the measured cellular uptakes are similar this implies a higher affinity of the Co system for the intracellular target(s); while the two systems are isostructural they have substantially different charge distributions as shown by calculated hydrophobicity maps. In contrast to the Λ enantiomer, Δ-Co(ii) induces G1 arrest in HCT116 cells, efficiently inhibits the topoisomerase I-catalyzed relaxation of supercoiled plasmid DNA, and, unlike the isostructural Fe(ii) system, causes DNA damage. It thus seems very likely that redox chemistry plays a role in the latter.
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Affiliation(s)
- Hualong Song
- Beijing Area Major Laboratory of Peptide and Small Molecular Drugs, Engineering Research Centre of Endogenous Prophylactic of Ministry of Education of China, School of Pharmaceutical Sciences, Capital Medical University Beijing 100069 China
- Department of Chemistry, University of Warwick Coventry CV4 7AL UK
| | - Hana Kostrhunova
- Czech Academy of Sciences, Institute of Biophysics Brno Czech Republic
| | - Jakub Cervinka
- Czech Academy of Sciences, Institute of Biophysics Brno Czech Republic
- Faculty of Science, Department of Biochemistry, Masaryk University Brno Czech Republic
| | - Julie Macpherson
- Department of Chemistry, University of Warwick Coventry CV4 7AL UK
| | - Jaroslav Malina
- Czech Academy of Sciences, Institute of Biophysics Brno Czech Republic
| | - Teena Rajan
- Department of Chemistry, University of Warwick Coventry CV4 7AL UK
| | - Roger Phillips
- Department of Pharmacy, University of Huddersfield Huddersfield HD1 3DH UK
| | - Miles Postings
- Department of Chemistry, University of Warwick Coventry CV4 7AL UK
| | - Samantha Shepherd
- Department of Pharmacy, University of Huddersfield Huddersfield HD1 3DH UK
| | - Xuejian Zhang
- College of Chemistry, State Key Laboratory of Elemento-Organic Chemistry, Nankai University Tianjin 300071 China
| | - Viktor Brabec
- Czech Academy of Sciences, Institute of Biophysics Brno Czech Republic
- Department of Biophysics, Palacky University Olomouc Czech Republic
| | - Nicola J Rogers
- Department of Chemistry, Hong Kong Baptist University Kowloon Tong Hong Kong SAR China
| | - Peter Scott
- Department of Chemistry, University of Warwick Coventry CV4 7AL UK
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2
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Gaynor RB, McIntyre BN, Lindsey SL, Clavo KA, Shy WE, Mees DE, Mu G, Donnadieu B, Creutz SE. Steric Effects on the Chelation of Mn 2+ and Zn 2+ by Hexadentate Polyimidazole Ligands: Modeling Metal Binding by Calprotectin Site 2. Chemistry 2023; 29:e202300447. [PMID: 37067464 PMCID: PMC10640917 DOI: 10.1002/chem.202300447] [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: 02/10/2023] [Revised: 04/14/2023] [Accepted: 04/17/2023] [Indexed: 04/18/2023]
Abstract
Recently, there has been increasing interest in the design of ligands that bind Mn2+ with high affinity and selectivity, but this remains a difficult challenge. It has been proposed that the cavity size of the binding pocket is a critical factor in most synthetic and biological examples of selective Mn2+ binding. Here, we use a bioinspired approach adapted from the hexahistidine binding site of the manganese-sequestering protein calprotectin to systematically study the effect of cavity size on Mn2+ and Zn2+ binding. We have designed a hexadentate, trisimidazole ligand whose cavity size can be tuned through peripheral modification of the steric bulk of the imidazole substituents. Conformational dynamics and redox potentials of the complexes are dependent on ligand steric bulk. Stability constants are consistent with the hypothesis that larger ligand cavities are relatively favorable for Mn2+ over Zn2+ , but this effect alone may not be sufficient to achieve Mn2+ selectivity.
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Affiliation(s)
- Ryan B Gaynor
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi, 39762, USA
| | - Baylee N McIntyre
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi, 39762, USA
| | - Shelby L Lindsey
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi, 39762, USA
| | - Kaylee A Clavo
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi, 39762, USA
| | - William E Shy
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi, 39762, USA
| | - David E Mees
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi, 39762, USA
| | - Ge Mu
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi, 39762, USA
| | - Bruno Donnadieu
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi, 39762, USA
| | - Sidney E Creutz
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi, 39762, USA
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3
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Coverdale JPC, Kostrhunova H, Markova L, Song H, Postings M, Bridgewater HE, Brabec V, Rogers NJ, Scott P. Triplex metallohelices have enantiomer-dependent mechanisms of action in colon cancer cells. Dalton Trans 2023; 52:6656-6667. [PMID: 37114730 DOI: 10.1039/d3dt00948c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
Self-assembled enantiomers of an asymmetric di-iron metallohelix differ in their antiproliferative activities against HCT116 colon cancer cells such that the compound with Λ-helicity at the metals becomes more potent than the Δ compound with increasing exposure time. From concentration- and temperature-dependent 57Fe isotopic labelling studies of cellular accumulation we postulate that while the more potent Λ enantiomer undergoes carrier-mediated efflux, for Δ the process is principally equilibrative. Cell fractionation studies demonstrate that both enantiomers localise in a similar fashion; compound is observed mostly within the cytoskeleton and/or genomic DNA, with significant amounts also found in the nucleus and membrane, but with negligible concentration in the cytosol. Cell cycle analyses using flow cytometry reveal that the Δ enantiomer induces mild arrest in the G1 phase, while Λ causes a very large dose-dependent increase in the G2/M population at a concentration significantly below the relevant IC50. Correspondingly, G2-M checkpoint failure as a result of Λ-metallohelix binding to DNA is shown to be feasible by linear dichroism studies, which indicate, in contrast to the Δ compound, a quite specific mode of binding, probably in the major groove. Further, spindle assembly checkpoint (SAC) failure, which could also be responsible for the observed G2/M arrest, is established as a feasible mechanism for the Λ helix via drug combination (synergy) studies and the discovery of tubulin and actin inhibition. Here, while the Λ compound stabilizes F-actin and induces a distinct change in tubulin architecture of HCT116 cells, Δ promotes depolymerization and more subtle changes in microtubule and actin networks.
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Affiliation(s)
- J P C Coverdale
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK
- School of Pharmacy, Institute of Clinical Sciences, University of Birmingham, Edgbaston, B15 2TT, UK
| | - H Kostrhunova
- The Czech Academy of Sciences, Institute of Biophysics, Kralovopolska 135, CZ-61265 Brno, Czech Republic
| | - L Markova
- The Czech Academy of Sciences, Institute of Biophysics, Kralovopolska 135, CZ-61265 Brno, Czech Republic
| | - H Song
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK
- Beijing Area Major Laboratory of Peptide and Small Molecular Drugs, School of Pharmaceutical Sciences, Capital Medical University, Beijing, 100069, China
| | - M Postings
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK
| | - H E Bridgewater
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK
- Centre of Exercise, Sport and Life Science, Faculty of Health and Life Sciences, Coventry University, Coventry, CV1 5FB, UK
| | - V Brabec
- The Czech Academy of Sciences, Institute of Biophysics, Kralovopolska 135, CZ-61265 Brno, Czech Republic
| | - N J Rogers
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK
| | - P Scott
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK
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4
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Xue W, Wu K, Ouyang N, Brotin T, Nitschke JR. Allosterically Regulated Guest Binding Determines Framework Symmetry for an Fe II 4 L 4 Cage. Angew Chem Int Ed Engl 2023; 62:e202301319. [PMID: 36866857 PMCID: PMC10947561 DOI: 10.1002/anie.202301319] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Indexed: 03/04/2023]
Abstract
Self-assembly of a flexible tritopic aniline and 3-substituted 2-formylpyridine subcomponents around iron(II) templates gave rise to a low-spin FeII 4 L4 capsule, whereas a high-spin FeII 3 L2 sandwich species formed when a sterically hindered 6-methyl-2-formylpyridine was used. The FeII 4 L4 cage adopted a new structure type with S4 symmetry, having two mer-Δ and two mer-Ʌ metal vertices, as confirmed by NMR and X-ray crystallographic analysis. The flexibility of the face-capping ligand endows the resulting FeII 4 L4 framework with conformational plasticity, enabling it to adapt structurally from S4 to T or C3 symmetry upon guest binding. The cage also displayed negative allosteric cooperativity in simultaneously binding different guests within its cavity and at the apertures between its faces.
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Affiliation(s)
- Weichao Xue
- Yusuf Hamied Department of ChemistryUniversity of CambridgeCambridgeCB2 1EWUK
| | - Kai Wu
- Yusuf Hamied Department of ChemistryUniversity of CambridgeCambridgeCB2 1EWUK
| | - Nianfeng Ouyang
- Yusuf Hamied Department of ChemistryUniversity of CambridgeCambridgeCB2 1EWUK
| | - Thierry Brotin
- Laboratoire de chimieUniversité LyonEns de Lyon, CNRS UMR 518269342LyonFrance
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5
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Gaynor RB, McIntyre BN, Creutz SE. (4-(Adamantan-1-yl)-1-(isopropyl)-1 H-imidazol-2-yl)methanol. MOLBANK 2023; 2023:M1566. [PMID: 37982079 PMCID: PMC10655578 DOI: 10.3390/m1566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2023] Open
Abstract
(4-(Adamantan-1-yl)-1-(isopropyl)-1H-imidazol-2-yl)methanol was prepared through a five-step process starting from commercially available 1-acetyladamantane. Each step proceeded in moderate-to-excellent yields and the overall yield across five steps was 28%. The compound was identified and characterized by 1H and 13C{1H} NMR, high-resolution mass spectroscopy, and elemental analysis. This compound and its derivatives have the potential to be used as precursors to the synthesis of biomimetic chelating ligands.
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Affiliation(s)
- Ryan B. Gaynor
- Department of Chemistry, Mississippi State University, Mississippi State, MS 39762, USA
| | - Baylee N. McIntyre
- Department of Chemistry, Mississippi State University, Mississippi State, MS 39762, USA
| | - Sidney E. Creutz
- Department of Chemistry, Mississippi State University, Mississippi State, MS 39762, USA
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6
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Sun B, Meeus EJ, de Zwart FJ, Bobylev EO, Mooibroek TJ, Mathew S, Reek JNH. Chirality-Driven Self-Assembly of Discrete, Homochiral Fe II 2 L 3 Cages. Chemistry 2023; 29:e202203900. [PMID: 36645137 DOI: 10.1002/chem.202203900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 01/13/2023] [Accepted: 01/16/2023] [Indexed: 01/17/2023]
Abstract
Coordination chemistry is a powerful method to synthesize supramolecular cages with distinct features that suit specific applications. This work demonstrates the synthesis of discrete, homochiral FeII 2 L3 cages via chirality-driven self-assembly. Specifically, the installation of chirality - at both the vertices and ligand backbones - allows the formation of discrete, homochiral FeII 2 L3 cages of different sizes via stereochemical control of the iron(II) centers. We observed that larger cages require multiple chiral centra (chiral ligands and vertices). In contrast, the formation of smaller cages is stereoselective with solely chiral ligands. The latter cages can also be formed from two chiral subcomponents, but only when they have matching chirality. Single-crystal X-ray diffraction of these smaller FeII 2 L3 cages revealed several non-covalent interactions as a driving force for narcissistic chiral self-sorting. This expected behavior was confirmed utilizing the shorter ligands in racemic form, yielding discrete, homochiral FeII 2 L3 cages formed in enantiomeric pairs.
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Affiliation(s)
- Bin Sun
- Homogeneous, Supramolecular and Bio-Inspired Catalysis group, van 't Hoff Institute for Molecular Sciences, University of Amsterdam (UvA), Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Eva J Meeus
- Homogeneous, Supramolecular and Bio-Inspired Catalysis group, van 't Hoff Institute for Molecular Sciences, University of Amsterdam (UvA), Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Felix J de Zwart
- Homogeneous, Supramolecular and Bio-Inspired Catalysis group, van 't Hoff Institute for Molecular Sciences, University of Amsterdam (UvA), Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Eduard O Bobylev
- Homogeneous, Supramolecular and Bio-Inspired Catalysis group, van 't Hoff Institute for Molecular Sciences, University of Amsterdam (UvA), Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Tiddo J Mooibroek
- Homogeneous, Supramolecular and Bio-Inspired Catalysis group, van 't Hoff Institute for Molecular Sciences, University of Amsterdam (UvA), Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Simon Mathew
- Homogeneous, Supramolecular and Bio-Inspired Catalysis group, van 't Hoff Institute for Molecular Sciences, University of Amsterdam (UvA), Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Joost N H Reek
- Homogeneous, Supramolecular and Bio-Inspired Catalysis group, van 't Hoff Institute for Molecular Sciences, University of Amsterdam (UvA), Science Park 904, 1098 XH, Amsterdam, The Netherlands
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7
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Carrillo U, Francés-Monerris A, Marri AR, Cebrián C, Gros PC. Substituent-Induced Control of fac/ mer Isomerism in Azine-NHC Fe(II) Complexes. ACS ORGANIC & INORGANIC AU 2022; 2:525-536. [PMID: 36855530 PMCID: PMC9955161 DOI: 10.1021/acsorginorgau.2c00038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 09/12/2022] [Accepted: 09/13/2022] [Indexed: 11/29/2022]
Abstract
The stereoselective synthesis of geometrical iron(II) complexes bearing azine-NHC ligands is described. Facial and meridional selectivity is achieved as a function of the steric demand of the azine unit, with no remarkable influence of the carbene nature. More specifically, meridional complexes are obtained upon selecting bulky 5-mesityl-substituted pyridyl coordinating units. Unexpectedly, increase of the steric hindrance in the α position with respect to the N coordinating atom results in an exclusive facial configuration, which is in stark contrast to the meridional selectivity induced by other reported α-substituted bidentate ligands. Investigation of the structure and the optical and electrochemical properties of the here-described complexes has revealed the non-negligible effect of the fac/mer ligand configuration around the metal center.
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8
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Xue W, Ronson TK, Lu Z, Nitschke JR. Solvent Drives Switching between Λ and Δ Metal Center Stereochemistry of M 8L 6 Cubic Cages. J Am Chem Soc 2022; 144:6136-6142. [PMID: 35364808 PMCID: PMC9098163 DOI: 10.1021/jacs.2c00245] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
![]()
An
enantiopure ligand with four bidentate metal-binding sites and
four (S)-carbon stereocenters self-assembles with
octahedral ZnII or CoII to produce O-symmetric M8L6 coordination cages. The Λ-
or Δ-handedness of the metal centers forming the corners of
these cages is determined by the solvent environment: the same (S)-ligand produces one diastereomer, (S)24-Λ8-M8L6, in
acetonitrile but another with opposite metal-center handedness, (S)24-Δ8-M8L6, in nitromethane. Van ’t Hoff analysis revealed the Δ
stereochemical configuration to be entropically favored but enthalpically
disfavored, consistent with a loosening of the coordination sphere
and an increase in conformational freedom following Λ-to-Δ
transition. The binding of 4,4′-dipyridyl naphthalenediimide
and tetrapyridyl Zn-porphyrin guests did not interfere with the solvent-driven
stereoselectivity of self-assembly, suggesting applications where
either a Λ- or Δ-handed framework may enable chiral separations
or catalysis.
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Affiliation(s)
- Weichao Xue
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Tanya K Ronson
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Zifei Lu
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Jonathan R Nitschke
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
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9
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Duan YH, Zhu XZ, Zhang Q, Yang Y. Molecular Enantiopure Homometallic Zn14L24 Cubic Cages with Luminescence Properties. INORG CHEM COMMUN 2022. [DOI: 10.1016/j.inoche.2022.109479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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10
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Basu Baul TS, Chaurasiya A, Vasquez-Ríos MG, Höpfl H. Zinc(II) complexes constructed from an adamantane-functionalized pyridine Schiff base - Influence of the counterion on the supramolecular organization by means of C-H⋅⋅⋅O, C-H⋅⋅⋅N, C-H⋅⋅⋅π and π⋅⋅⋅π interactions. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2021.131241] [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]
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11
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A curved host and second guest cooperatively inhibit the dynamic motion of corannulene. Nat Commun 2021; 12:4079. [PMID: 34215736 PMCID: PMC8253762 DOI: 10.1038/s41467-021-24344-w] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 06/10/2021] [Indexed: 11/08/2022] Open
Abstract
Biomolecular systems show how host-guest binding can induce changes in molecular behavior, which in turn impact the functions of the system. Here we report an artificial host-guest system where dynamic adaptation during guest binding alters both host conformation and guest dynamics. The self-assembled cage host employed here possesses concave walls and a chirotopic cavity. Complementarity between the curved surfaces of fullerenes and the inner surface of the host cavity leads the host to reconfigure stereochemically in order to bind these guests optimally. The curved molecule corannulene undergoes rapid bowl-to-bowl inversion at room temperature. Its inversion barrier is increased upon binding, however, and increased further upon formation of a ternary complex, where corannulene and a cycloalkane are both bound together. The chiral nature of the host also leads to clear differences in the NMR spectra of ternary complexes involving corannulene and one or the other enantiomer of a chiral guest, which enables the determination of enantiomeric excess by NMR.
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12
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Carpenter JP, McTernan CT, Greenfield JL, Lavendomme R, Ronson TK, Nitschke JR. Controlling the shape and chirality of an eight-crossing molecular knot. Chem 2021. [DOI: 10.1016/j.chempr.2021.03.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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13
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Thomas F, Oster M, Schön F, Göbgen KC, Amarouch B, Steden D, Hoffmann A, Herres-Pawlis S. A new generation of terminal copper nitrenes and their application in aromatic C-H amination reactions. Dalton Trans 2021; 50:6444-6462. [PMID: 33908532 DOI: 10.1039/d1dt00832c] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Copper nitrene complexes are highly reactive species and are known as intermediates in the copper catalyzed C-H amination. In this study, three novel copper tosyl nitrene complexes were synthesized at low temperatures, stabilized with heteroscorpionate ligands of the bis(pyrazolyl)methane family. The copper nitrenes were obtained by the reaction of a copper(i) acetonitrile complex with SPhINTs in dichloromethane. We show that the ligand design has a major influence on the catalytic activity and the thermal stability of the copper nitrene complex. Not only the choice of the third N donor, but also the substituent in the 5-position of the pyrazolyl moiety, have an impact on the stability. Furthermore, the novel copper nitrene complexes were used for catalytic aziridination of styrenes and C-H amination reactions of aromatic and aliphatic substrates under mild reaction conditions. Even challenging substrates like benzene and cyclohexane were aminated with good yields. The copper nitrene complexes were characterized using UV/Vis spectroscopy, low temperature Evans NMR spectroscopy, density functional theory, domain-based local pair natural orbital coupled cluster calculations (DLPNO-CCSD(T)) and cryo-UHR mass spectrometry.
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Affiliation(s)
- Fabian Thomas
- Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1a, 52074 Aachen, Germany.
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14
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Morozumi T, Matsuoka R, Nakamura T, Nabeshima T. Solvent-dependent fac/ mer-isomerization and self-assembly of triply helical complexes bearing a pivot part. Chem Sci 2021; 12:7720-7726. [PMID: 34168824 PMCID: PMC8188510 DOI: 10.1039/d1sc01529j] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Tris-chelate metal complexes of unsymmetrical bidentate ligands can form two geometric stereoisomers, facial (fac) and meridional (mer) isomers. Due to the small difference in their properties, the highly-selective synthesis of one of the isomers is challenging. We now designed a series of tripodal ligands with a tris(3-(2-(methyleneoxy)ethoxy)phenyl)methane pivot. Surprisingly, the ratio of the fac/mer isomers of the triply helical FeII complexes significantly changed depending on the solvents. To the best of our knowledge, this is the first example of fac/mer isomerism of a labile tris(2,2'-bipyridine) FeII complex governed by the solvent. Furthermore, well-defined self-assemblies were quantitatively produced by imine bond formation with a suitable diamine. The supramolecular assemblies contained only the fac isomer even though a mixture of the two isomers existed in solution before the condensation reaction. Namely, the self-assembly formation effectively adjusted the geometries of the building unit that results in the suitable supramolecular structure.
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Affiliation(s)
- Takuma Morozumi
- Faculty of Pure and Applied Sciences and Tsukuba Research Center for Energy Materials Science (TREMS), University of Tsukuba 1-1-1 Tennodai, Tsukuba Ibaraki 305-8571 Japan
| | - Ryota Matsuoka
- Faculty of Pure and Applied Sciences and Tsukuba Research Center for Energy Materials Science (TREMS), University of Tsukuba 1-1-1 Tennodai, Tsukuba Ibaraki 305-8571 Japan
| | - Takashi Nakamura
- Faculty of Pure and Applied Sciences and Tsukuba Research Center for Energy Materials Science (TREMS), University of Tsukuba 1-1-1 Tennodai, Tsukuba Ibaraki 305-8571 Japan
| | - Tatsuya Nabeshima
- Faculty of Pure and Applied Sciences and Tsukuba Research Center for Energy Materials Science (TREMS), University of Tsukuba 1-1-1 Tennodai, Tsukuba Ibaraki 305-8571 Japan
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15
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Song H, Postings M, Scott P, Rogers NJ. Metallohelices emulate the properties of short cationic α-helical peptides. Chem Sci 2021; 12:1620-1631. [PMID: 34163922 PMCID: PMC8179244 DOI: 10.1039/d0sc06412b] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Accepted: 12/24/2020] [Indexed: 12/15/2022] Open
Abstract
Naturally occurring peptides in many living systems perform antimicrobial and anticancer host defence roles, but their potential for clinical application is limited by low metabolic stability and relatively high costs of goods. Self-assembled helical metal complexes provide an attractive synthetic platform for non-peptidic architectures that can emulate some of the properties of short cationic α-helical peptides, with tuneable charge, shape, size and amphipathicity. Correspondingly there is a growing body of evidence demonstrating that these supramolecular architectures exhibit bioactivity that emulates that of the natural systems. We review that evidence in the context of synthetic advances in the area, driven by the potential for biomedical applications. We note some design considerations for new biologically-relevant metallohelices, and give our outlook on the future of these compounds as therapeutic peptidomimetics.
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16
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Pajuelo-Corral O, Zabala-Lekuona A, San Sebastian E, Rodríguez-Diéguez A, García JA, Lezama L, Colacio E, Seco JM, Cepeda J. Modulating Magnetic and Photoluminescence Properties in 2-Aminonicotinate-Based Bifunctional Coordination Polymers by Merging 3d Metal Ions. Chemistry 2020; 26:13484-13498. [PMID: 32668065 DOI: 10.1002/chem.202002755] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 07/13/2020] [Indexed: 12/23/2022]
Abstract
Herein, the synthesis and study of bifunctional coordination polymers (CPs) with both magnetic and photoluminescence properties, derived from a heterometallic environment, are reported. As a starting point, three isostructural monometallic CPs with the formula [M(μ-2ani)2 ]n (MII =Mn (1Mn ), Co (3Co ) and Ni (4Ni ); 2ani=2-aminonicotinate), crystallise as chiral 2D-layered structures stacked by means of supramolecular interactions. These compounds show high thermal stability in the solid state (above 350 °C), despite which, in aqueous solution, compound 1Mn is shown to partially transform into a novel 1D chain CP with the formula [Mn(2ani)2 (μ-H2 O)2 ]n (2Mn ). A study of the direct current (dc) magnetic properties of 1Mn , 3Co and 4Ni reveals a spin-canted structure derived from antisymmetric antiferromagnetic weak exchanges along the chiral network (as confirmed by DFT calculations) and magnetic anisotropy of the ions, in such a way that long-range ordering is observed with variable magnitude for the spin carriers. Moreover, compounds 3Co and 4Ni show no frequency-dependent alternating current (ac) susceptibility curves under zero dc field; this is characteristic behaviour of a glassy state that may be partially supressed for 3Co by applying an external dc field. To overcome long-range magnetic ordering, CoII ions are diluted in a diamagnetic ZnII -based matrix, which enables single-molecule magnet behaviour. Interestingly, this strategy allows a bifunctional Cox Zn1-x 2ani material, which is imbued with a strong photoluminescent emitting capacity, as characterised by an intense blue light followed by a green afterglow, to be obtained.
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Affiliation(s)
- Oier Pajuelo-Corral
- Departamento de Química Aplicada, Facultad de Química, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), 20018, Donostia, Spain
| | - Andoni Zabala-Lekuona
- Departamento de Química Aplicada, Facultad de Química, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), 20018, Donostia, Spain
| | - Eider San Sebastian
- Departamento de Química Aplicada, Facultad de Química, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), 20018, Donostia, Spain
| | - Antonio Rodríguez-Diéguez
- Departamento de Química Inorgánica, Facultad de Ciencias, Universidad de Granada, 18071, Granada, Spain
| | - Jose Angel García
- Departamento de Física Aplicada II, Facultad de Ciencia y Tecnología, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), 48940, Leioa, Spain
| | - Luis Lezama
- Departamento de Química Inorgánica, Facultad de Ciencia y Tecnología, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), 48940, Leioa, Spain
| | - Enrique Colacio
- Departamento de Química Inorgánica, Facultad de Ciencias, Universidad de Granada, 18071, Granada, Spain
| | - Jose M Seco
- Departamento de Química Aplicada, Facultad de Química, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), 20018, Donostia, Spain
| | - Javier Cepeda
- Departamento de Química Aplicada, Facultad de Química, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), 20018, Donostia, Spain
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Mandal A, Nath B, Patel BK. Unraveling the role of non-covalent interactions to determine chiral selectivity in coordination compounds of racemic 1,2-dihydroquinazolinone ligands. Polyhedron 2020. [DOI: 10.1016/j.poly.2020.114730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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18
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Plajer AJ, Rizzuto FJ, von Krbek LKS, Gisbert Y, Martínez-Agramunt V, Nitschke JR. Oxidation triggers guest dissociation during reorganization of an Fe II 4L 6 twisted parallelogram. Chem Sci 2020; 11:10399-10404. [PMID: 34123180 PMCID: PMC8162311 DOI: 10.1039/d0sc04352d] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Accepted: 09/09/2020] [Indexed: 12/12/2022] Open
Abstract
A three-dimensional FeII 4L6 parallelogram was prepared from ferrocene-containing ditopic ligands. The steric preference of the bulky ferrocene cores towards meridional vertex coordination brought about this new structure type, in which the ferrocene units adopt three distinct conformations. The structure possesses two distinct, bowl-like cavities that host anionic guests. Oxidation of the ferrocene FeII to ferrocenium FeIII causes rotation of the ferrocene hinges, converting the structure to an FeII 1L1 + species with release of anionic guests, even though the average charge per iron increases in a way that would ordinarily increase guest binding strength. The degrees of freedom exhibited by these new structures - derived from the different configurations of the three ligands surrounding a meridional FeII center and the rotation of ferrocene cores - thus underpin their ability to reconfigure and eject guests upon oxidation.
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Affiliation(s)
- Alex J Plajer
- Department of Chemistry, University of Cambridge Lensfield Rd Cambridge CB2 1EW UK
| | - Felix J Rizzuto
- Department of Chemistry, University of Cambridge Lensfield Rd Cambridge CB2 1EW UK
| | | | - Yohan Gisbert
- Department of Chemistry, University of Cambridge Lensfield Rd Cambridge CB2 1EW UK
| | | | - Jonathan R Nitschke
- Department of Chemistry, University of Cambridge Lensfield Rd Cambridge CB2 1EW UK
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Structural Evidence of Spin State Selection and Spin Crossover Behavior of Tripodal Schiff Base Complexes of tris(2-aminoethyl)amine and Related Tripodal Amines. MAGNETOCHEMISTRY 2020. [DOI: 10.3390/magnetochemistry6020028] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A review of the tripodal Schiff base (SB) complexes of tris(2-aminoethyl)amine, Nap(CH2CH 2NH2)3 (tren), and a few closely related tripodal amines with Cr(II), Mn(III) (d4), Mn(II), Fe(III) (d5), Fe(II) (d6), and Co(II) (d7) is provided. Attention is focused on examination of key structural features, the M-Nimine, M-Namine, or M-O and M-Nap bond distances and Nimine-M-N(O) bite and C-Nap-C angles and how these values correlate with spin state selection and spin crossover (SCO) behavior. A comparison of these experimental values with density functional theory calculated values is also given. The greatest number, 132, of complexes is observed with cationic mononuclear iron(II) in a N6 donor set, Fe(II)N6. The dominance of two spin states, high spin (HS) and low spin (LS), in these systems is indicated by the bimodal distribution of histogram plots of Fe(II)-Nimine and Fe(II)-Nazole/pyridine bond distances and of Nimine–Fe(II)-Nazole/pyridine and C-Nap-C bond angles. The values of the two maxima, corresponding to LS and HS states, in each of these histograms agree closely with the theoretical values. The iron(II)-Nimine and iron(II)-Nazole/pyridine bond distances correlate well for these complexes. Examples of SCO complexes of this type are tabulated and a few of the 20 examples are discussed that exhibit interesting features. There are only a few mononuclear iron(III) cationic complexes and one is SCO. In addition, a significant number of supramolecular complexes of these ligands that exhibit SCO, intervalence, and chiral recognition are discussed. A summary is made regarding the current state of this area of research and possible new avenues to explore based on analysis of the present data.
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20
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Mandal A, Ghosh S, Nath B, Patel BK. Role of non-covalent interactions to dictate chiral selective self-assembly in Ni(II), Cu(II) and Cd(II) complexes of a racemic 1,2-dihydroquinazolinone ligand. Inorganica Chim Acta 2020. [DOI: 10.1016/j.ica.2019.119399] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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21
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Chiral resolution of 1-phenylethylamine in Schiff base form within a mixed ligand complex of Ni(II). Inorganica Chim Acta 2020. [DOI: 10.1016/j.ica.2019.119338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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22
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Barry KL, Grimmer CD, Munro OQ, Akerman MP. Self-assembled supramolecular structures of O, N, N' tridentate imidazole-phenol Schiff base compounds. RSC Adv 2020; 10:7867-7878. [PMID: 35492155 PMCID: PMC9049879 DOI: 10.1039/c9ra10488g] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 02/16/2020] [Indexed: 01/25/2023] Open
Abstract
Three imidazole-derived Schiff base compounds comprising an N-methyl imidazole group coupled to a phenol ring through an imine bond were synthesised. The structures differ by the substituent on the phenol ring at the 4-position: methyl (1), tert-butyl (2) and hydrogen (3). The compounds were synthesised using both a traditional reflux in solvent as well as an environmentally friendly solid-state reaction. Compounds (1)–(3) as well as the hemihydrate of (3) were all studied by single crystal X-ray diffraction. The asymmetric unit of compound (1) consists of two nominally planar molecules linked by hydrogen bonds to form a dimeric supramolecular structure. This dimeric structure was ubiquitous for the anhydrous forms of (1)–(3). The complementary hydrogen bonding motif between the imidazole N atoms and the phenol OH results in a stable 16-membered hydrogen-bonded ring. The asymmetric unit of (3) comprises two symmetry-independent molecules one of which has co-planar imidazole and phenol rings while the other shows a significantly oblique orientation. The hemihydrate of (3) similarly forms extensive hydrogen bonds, though in the form of a water-bridged dimeric structure. The hydrogen bond lengths (D⋯A) for compounds (1)–(3) are relatively short, ranging from 2.662(1) to 2.688(1) Å. DFT was used to understand the relative stability of the monomeric and dimeric species. These showed the hydrogen-bonded supramolecular structures were ca. 101 kJ mol−1 lower in energy than the non-interacting monomers. Scan simulations were used to calculate the total energy of the molecule as a function of phenyl ring rotation and showed why the expected planar configuration for a conjugated π-system was not observed experimentally. The barrier to rotation was found to be relatively low, 7.97(6) kJ mol−1, with the lowest energy conformations subtending dihedral angles of 22.319, 24.265 and 25.319° for molecules (1), (2) and (3), respectively. The electrostatic potential maps are able to succinctly explain the stability of the hydrogen bonds through the partial charges of the interacting atoms. TD-DFT simulations and analysis of the simulated and experimental UV/visible spectra suggest that the dimeric supramolecular structure is a stable species in solution. This was confirmed through 1H NMR titrations and an equilibrium constant of 0.16(5) M−1 was estimated. Three imidazole-derived Schiff base compounds comprising an N-methyl imidazole group coupled to a phenol ring through an imine bond were synthesised. The solid state and solution state supramolecular structures as well as energetics are explored.![]()
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Affiliation(s)
- Kristy-Lyn Barry
- School of Chemistry and Physics, University of KwaZulu-Natal Private Bag X01, Scottsville Pietermaritzburg 3209 South Africa
| | - Craig D Grimmer
- School of Chemistry and Physics, University of KwaZulu-Natal Private Bag X01, Scottsville Pietermaritzburg 3209 South Africa
| | - Orde Q Munro
- Molecular Sciences Institute, School of Chemistry, WITS University Johannesburg South Africa
| | - Matthew P Akerman
- School of Chemistry and Physics, University of KwaZulu-Natal Private Bag X01, Scottsville Pietermaritzburg 3209 South Africa
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23
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Simpson DH, Hapeshi A, Rogers NJ, Brabec V, Clarkson GJ, Fox DJ, Hrabina O, Kay GL, King AK, Malina J, Millard AD, Moat J, Roper DI, Song H, Waterfield NR, Scott P. Metallohelices that kill Gram-negative pathogens using intracellular antimicrobial peptide pathways. Chem Sci 2019; 10:9708-9720. [PMID: 32015803 PMCID: PMC6977464 DOI: 10.1039/c9sc03532j] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 09/04/2019] [Indexed: 12/24/2022] Open
Abstract
A range of new water-compatible optically pure metallohelices - made by self-assembly of simple non-peptidic organic components around Fe ions - exhibit similar architecture to some natural cationic antimicrobial peptides (CAMPs) and are found to have high, structure-dependent activity against bacteria, including clinically problematic Gram-negative pathogens. A key compound is shown to freely enter rapidly dividing E. coli cells without significant membrane disruption, and localise in distinct foci near the poles. Several related observations of CAMP-like mechanisms are made via biophysical measurements, whole genome sequencing of tolerance mutants and transcriptomic analysis. These include: high selectivity for binding of G-quadruplex DNA over double stranded DNA; inhibition of both DNA gyrase and topoisomerase I in vitro; curing of a plasmid that contributes to the very high virulence of the E. coli strain used; activation of various two-component sensor/regulator and acid response pathways; and subsequent attempts by the cell to lower the net negative charge of the surface. This impact of the compound on multiple structures and pathways corresponds with our inability to isolate fully resistant mutant strains, and supports the idea that CAMP-inspired chemical scaffolds are a realistic approach for antimicrobial drug discovery, without the practical barriers to development that are associated with natural CAMPS.
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Affiliation(s)
- Daniel H Simpson
- Department of Chemistry , University of Warwick , Gibbet Hill Road , Coventry , CV4 7AL , UK .
| | - Alexia Hapeshi
- Warwick Medical School , University of Warwick , Coventry , CV4 7AL , UK
| | - Nicola J Rogers
- Department of Chemistry , University of Warwick , Gibbet Hill Road , Coventry , CV4 7AL , UK .
| | - Viktor Brabec
- The Czech Academy of Sciences , Institute of Biophysics , Kralovopolska 135 , CZ-61265 Brno , Czech Republic
| | - Guy J Clarkson
- Department of Chemistry , University of Warwick , Gibbet Hill Road , Coventry , CV4 7AL , UK .
| | - David J Fox
- Department of Chemistry , University of Warwick , Gibbet Hill Road , Coventry , CV4 7AL , UK .
| | - Ondrej Hrabina
- The Czech Academy of Sciences , Institute of Biophysics , Kralovopolska 135 , CZ-61265 Brno , Czech Republic
- Department of Biophysics , Palacky University , Slechtitelu 27 , 783 71 Olomouc , Czech Republic
| | - Gemma L Kay
- Warwick Medical School , University of Warwick , Coventry , CV4 7AL , UK
| | - Andrew K King
- Department of Chemistry , University of Warwick , Gibbet Hill Road , Coventry , CV4 7AL , UK .
| | - Jaroslav Malina
- The Czech Academy of Sciences , Institute of Biophysics , Kralovopolska 135 , CZ-61265 Brno , Czech Republic
| | - Andrew D Millard
- Warwick Medical School , University of Warwick , Coventry , CV4 7AL , UK
| | - John Moat
- School of Life Sciences , University of Warwick , Gibbet Hill Campus , Coventry , CV4 7AL , UK
| | - David I Roper
- School of Life Sciences , University of Warwick , Gibbet Hill Campus , Coventry , CV4 7AL , UK
| | - Hualong Song
- Department of Chemistry , University of Warwick , Gibbet Hill Road , Coventry , CV4 7AL , UK .
| | | | - Peter Scott
- Department of Chemistry , University of Warwick , Gibbet Hill Road , Coventry , CV4 7AL , UK .
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24
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Dumitru F, van der Lee A, Barboiu M. Chiral superstructures from homochiral Zn 2+ , Co 2+ , Fe 2+ -2,6-bis (aryl ethylimine)pyridine complexes. Chirality 2019; 31:763-775. [PMID: 31392782 DOI: 10.1002/chir.23115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 06/15/2019] [Accepted: 07/06/2019] [Indexed: 11/07/2022]
Abstract
We report the hierarchical supramolecular organization of metallosupramolecular homochiral complexes 1-Λ-(S,S,S,S)-M2+ /1-∆-(R,R,R,R)-M2+ and 2- Λ-(S,S,S,S)-M2+ /2-∆- (R,R,R,R)-M2+ of M2+ = Co2+ , Fe2+ , Zn2+ metal ions with chiral pseudo-terpyridine-type ligands: 1-(S,S) or 1-(R,R) = 2,6-bis (naphthyl ethylimine)pyridine and 2-(S,S) or 2-(R,R) = 2,6-bis (phenyl-ethylimine)pyridine. Circular dichroism measurements in solution were used to confirm the enantiomeric nature of all twelve complexes. For crystal structures of 1- Λ- (S,S,S,S)-M2+ or 1-∆- (R,R,R,R)-M2+ complexes, absolute configurations {∆ (or P), Λ (or M)} were confirmed by refinement of the Flack parameter x: -0.007 ≤ x ≤ 0.11 for the single crystals of 1-Λ-(S,S,S,S)-M2+ /1-∆- (R,R,R,R)-M2+ , 2- Λ- (S,S,S,S)-Fe2+ , and 2-∆- (R,R,R,R)-Co2+ .
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Affiliation(s)
- Florina Dumitru
- Institut Européen des Membranes, UMR-CNRS 5635, Université Montpellier, ENSCM Place eugene Bataillon CC047, Montpellier, France.,Faculty of Applied Chemistry and Materials Science, Department of Inorganic Chemistry, Physical Chemistry and Electrochemistry, University Politehnica of Bucharest, Bucharest, Romania
| | - Arie van der Lee
- Institut Européen des Membranes, UMR-CNRS 5635, Université Montpellier, ENSCM Place eugene Bataillon CC047, Montpellier, France
| | - Mihail Barboiu
- Institut Européen des Membranes, UMR-CNRS 5635, Université Montpellier, ENSCM Place eugene Bataillon CC047, Montpellier, France
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25
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Sun B, Nurttila SS, Reek JNH. Synthesis and Characterization of Self-Assembled Chiral Fe II 2 L 3 Cages. Chemistry 2018; 24:14693-14700. [PMID: 30025184 PMCID: PMC6175241 DOI: 10.1002/chem.201801077] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 07/16/2018] [Indexed: 11/23/2022]
Abstract
We present here the synthesis of chiral BINOL-derived (BINOL=1,1'-bi-2-naphthol) bisamine and bispyridine-aldehyde building blocks that can be used for the self-assembly of novel chiral FeII 2 L3 cages when mixed with an iron(II) precursor. The properties of a series of chiral cages were studied by NMR and circular dichroism (CD) spectroscopy, cold-spray ionization MS, and molecular modeling. Upon formation of the M2 L3 cages, the iron corners can adopt various isomeric forms: mer, fac-Δ, or fac-Λ. We found that the coordination geometry around the metal centers in R-Cages 1 and 2 were influenced by the chiral BINOL backbone only to a limited extent, as a mixture of cages was formed with fac and mer configurations at the iron corners. However, single cage species (fac-RR-Cage and fac-RS-Cage) that are enantiopure and highly symmetric were obtained by generating these chiral M2 L3 cages by using the bispyridine-aldehyde building blocks in combination with chiral amine moieties to form pyridylimine ligands for coordination to iron. Next to consistent NMR spectra, the CD spectra confirm the configurations fac-(Λ,Λ) and fac-(Δ,Δ) corresponding to RR- and RS-Cage, respectively.
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Affiliation(s)
- Bin Sun
- Homogeneous, Bioinspired and Supramolecular Catalysis, van 't Hoff Institute for Molecular SciencesUniversity of AmsterdamScience Park 9041098XHAmsterdamThe Netherlands
| | - Sandra S. Nurttila
- Homogeneous, Bioinspired and Supramolecular Catalysis, van 't Hoff Institute for Molecular SciencesUniversity of AmsterdamScience Park 9041098XHAmsterdamThe Netherlands
| | - Joost N. H. Reek
- Homogeneous, Bioinspired and Supramolecular Catalysis, van 't Hoff Institute for Molecular SciencesUniversity of AmsterdamScience Park 9041098XHAmsterdamThe Netherlands
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26
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Scott HS, Staniland RW, Kruger PE. Spin crossover in homoleptic Fe(II) imidazolylimine complexes. Coord Chem Rev 2018. [DOI: 10.1016/j.ccr.2018.02.001] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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27
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García F, Pelss J, Zuilhof H, Smulders MMJ. Multi-responsive coordination polymers utilising metal-stabilised, dynamic covalent imine bonds. Chem Commun (Camb) 2018; 52:9059-62. [PMID: 26879208 DOI: 10.1039/c6cc00500d] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report how the combination of dynamic covalent imine bonds and coordination bonds in a single polymer material not only imparts enhanced stability to the final polymer, but also allows the material to be sensitive to a range of stimuli, offering more fine-grained control over its properties.
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Affiliation(s)
- Fátima García
- Laboratory of Organic Chemistry, Wageningen University, Dreijenplein 8, 6703 HB Wageningen, The Netherlands.
| | - Janis Pelss
- Laboratory of Organic Chemistry, Wageningen University, Dreijenplein 8, 6703 HB Wageningen, The Netherlands.
| | - Han Zuilhof
- Laboratory of Organic Chemistry, Wageningen University, Dreijenplein 8, 6703 HB Wageningen, The Netherlands. and Department of Chemical and Materials Engineering, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Maarten M J Smulders
- Laboratory of Organic Chemistry, Wageningen University, Dreijenplein 8, 6703 HB Wageningen, The Netherlands.
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28
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Marais L, Burés J, Jordaan JHL, Mapolie S, Swarts AJ. A bis(pyridyl)-N-alkylamine/Cu(i) catalyst system for aerobic alcohol oxidation. Org Biomol Chem 2017; 15:6926-6933. [PMID: 28776055 DOI: 10.1039/c7ob01383c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Herein a bis(pyridyl)-N-alkylamine/CuI/TEMPO/NMI catalyst system is reported for aerobic oxidation of a variety of primary alcohols to the corresponding aldehydes using readily available reagents, at room temperature and ambient air as the oxidant. ESI-MS analysis of the reaction showed the formation of a [(L1)(NMI)CuII-OOH]+ species, which is a key intermediate in the alcohol oxidation reaction. Evaluation of the effect of reaction parameters on the initial rate of the reaction allowed us to obtain the optimum conditions for catalytic activity. The careful choice of reaction solvent allowed for the oxidation of 4-hydroxybenzyl alcohol, a substrate which proved problematic in previous studies. In the case of 2-pyridinemethanol as substrate, experimental evidence shows that catalytic activity is diminished due to competitive inhibition of the catalyst by the alcohol substrate.
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Affiliation(s)
- Lindie Marais
- Catalysis and Synthesis Research Group, Focus Area for Chemical Resource Beneficiation, North-West University, 11 Hoffman Street, Potchefstroom 2520, South Africa.
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29
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Burrows KE, McGrath SE, Kulmaczewski R, Cespedes O, Barrett SA, Halcrow MA. Spin States of Homochiral and Heterochiral Isomers of [Fe(PyBox) 2 ] 2+ Derivatives. Chemistry 2017; 23:9067-9075. [PMID: 28387453 DOI: 10.1002/chem.201700820] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Indexed: 11/08/2022]
Abstract
The following iron(II) complexes of 2,6-bis(oxazolinyl)pyridine (PyBox; LH ) derivatives are reported: [Fe(LH )2 ][ClO4 ]2 (1); [Fe((R)-LMe )2 ][ClO4 ]2 ((R)-2; LMe =2,6-bis{4-methyloxazolinyl}pyridine); [Fe((R)-LPh )2 ][ClO4 ]2 ((R)-3) and [Fe((R)-LPh )((S)-LPh )][ClO4 ]2 ((RS)-3; LPh =2,6-bis{4-phenyloxazolinyl}pyridine); and [Fe((R)-LiPr )2 ][ClO4 ]2 ((R)-4) and [Fe((R)-LiPr )((S)-LiPr )][ClO4 ]2 ((RS)-4; LiPr =2,6-bis{4-isopropyloxazolinyl}pyridine). Solid (R)-3⋅MeNO2 exhibits an unusual very gradual, but discontinuous thermal spin-crossover with an approximate T1/2 of 350 K. The discontinuity around 240 K lies well below T1/2 , and is unconnected to a crystallographic phase change occurring at 170 K. Rather, it can be correlated with a gradual ordering of the ligand conformation as the temperature is raised. The other solid compounds either exhibit spin-crossover above room temperature (1 and (RS)-3), or remain high-spin between 5-300 K [(R)-2, (R)-4 and (RS)-4]. Homochiral (R)-3 and (R)-4 exhibit more twisted ligand conformations and coordination geometries than their heterochiral isomers, which can be attributed to steric clashes between ligand substituents [(R)-3]; or, between the isopropyl substituents of one ligand and the backbone of the other ((R)-4). In solution, (RS)-3 retains its structural integrity but (RS)-4 undergoes significant racemization through ligand redistribution by 1 H NMR. (R)-4 and (RS)-4 remain high-spin in solution, whereas the other compounds all undergo spin-crossover equilibria. Importantly, T1/2 for (R)-3 (244 K) is 34 K lower than for (RS)-3 (278 K) in CD3 CN, which is the first demonstration of chiral discrimination between metal ion spin states in a molecular complex.
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Affiliation(s)
- Kay E Burrows
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
| | - Sarah E McGrath
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
| | - Rafal Kulmaczewski
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
| | - Oscar Cespedes
- School of Physics and Astronomy, University of Leeds, E. C. Stoner Building, Leeds, LS2 9JT, UK
| | - Simon A Barrett
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
| | - Malcolm A Halcrow
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
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30
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Fujii A, Choi JC, Fujita KI. Synthesis of magnetically recoverable imidazolium hydrogen carbonate and its application as an N-heterocyclic carbene catalyst to cyanosilylation of aldehydes and ketones. Tetrahedron Lett 2017. [DOI: 10.1016/j.tetlet.2017.03.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Wang XR, Ma JP, Dong YB. Syntheses and structures of two new coordination polymers generated from a 4-aminotriazole-bridged organic ligand and Co II salts. Acta Crystallogr C 2017; 73:247-253. [PMID: 28257020 DOI: 10.1107/s2053229617001437] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 01/27/2017] [Indexed: 11/11/2022] Open
Abstract
Organic ligands and counter-anions influence the coordination spheres of metal cations and hence the construction of coordination polymers (CPs). The specific bent geometries of five-membered heterocyclic triazole bridging organic ligands are capable of generating CPs with novel patterns not easily obtained using rigid linear ligands. A multidentate 4-aminotriazole-bridged organic ligand, namely 4-amino-3,5-bis(4,3'-bipyridyl-5'-yl)-4H-1,2,4-triazole (L) has been prepared and used to synthesize two CoII coordination polymers, namely poly[[[μ2-4-amino-3,5-bis(4,3'-bipyridyl-5'-yl)-4H-1,2,4-triazole-κ2N:N']bis(methanol-κO)cobalt(II)] bis(perchlorate)], {[Co(C22H16N8)2(CH3OH)2](ClO4)2}n, (I), and poly[[μ3-4-amino-3,5-bis(4,3'-bipyridyl-5'-yl)-4H-1,2,4-triazole-κ3N:N':N'']dichloridocobalt(II)], [CoCl2(C22H16N8)]n, (II), using CoX2 salts [X = ClO4 for (I) and Cl for (II)] under solvothermal conditions. Single-crystal X-ray structure analysis revealed that they both feature two-dimensional networks. Cobalt is located on an inversion centre in (I) and in a general position in (II). In (I), L functions as a bidentate cis-conformation ligand linking CoII ions, while it functions as a tridentate trans-conformation linker binding CoII ions in (II). In addition, O-H...N and N-H...O hydrogen bonds and C-H...π interactions exist in (I), while N-H...Cl and π-π interactions exist in (II), and these weak interactions play an important role in aligning the two-dimensional nets of (I) and (II) in the solid state. As the compounds were synthesized under the same conditions, the significant structural variations between (I) and (II) are believed to be determined by the different sizes and coordination abilities of the counter-anions. IR spectroscopy and diffuse reflectance UV-Vis spectra were also used to investigate the title compounds.
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Affiliation(s)
- Xue Ru Wang
- College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan 250014, People's Republic of China
| | - Jian Ping Ma
- College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan 250014, People's Republic of China
| | - Yu Bin Dong
- College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan 250014, People's Republic of China
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Martir DR, Momblona C, Pertegás A, Cordes DB, Slawin AMZ, Bolink HJ, Zysman-Colman E. Chiral Iridium(III) Complexes in Light-Emitting Electrochemical Cells: Exploring the Impact of Stereochemistry on the Photophysical Properties and Device Performances. ACS APPLIED MATERIALS & INTERFACES 2016; 8:33907-33915. [PMID: 27960443 DOI: 10.1021/acsami.6b14050] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Despite hundreds of cationic bis-cyclometalated iridium(III) complexes having been explored as emitters for light-emitting electrochemical cells (LEECs), uniformly their composition has been in the form of a racemic mixture of Λ and Δ enantiomers. The investigation of LEECs using enantiopure iridium(III) emitters, however, remains unprecedented. Herein, we report the preparation, the crystal structures, and the optoelectronic properties of two families of cyclometalated iridium(III) complexes of the form of [(C^N)2Ir(dtBubpy)]PF6 (where dtBubpy is 4,4'-di-tert-butyl-2,2'-bipyridine) in both their racemic and enantiopure configurations. LEEC devices using Λ and Δ enantiomers as well as the racemic mixture of both families have been prepared, and the device performances were tested. Importantly, different solid-state photophysical properties exist between enantiopure and racemic emitters, which are also reflected in the device performances.
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Affiliation(s)
- Diego Rota Martir
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews , St Andrews, Fife KY16 9ST, United Kingdom
| | - Cristina Momblona
- Instituto de Ciencia Molecular, Universidad de Valencia , c/Catedrático J. Beltrán, 2, Paterna 46980, Spain
| | - Antonio Pertegás
- Instituto de Ciencia Molecular, Universidad de Valencia , c/Catedrático J. Beltrán, 2, Paterna 46980, Spain
| | - David B Cordes
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews , St Andrews, Fife KY16 9ST, United Kingdom
| | - Alexandra M Z Slawin
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews , St Andrews, Fife KY16 9ST, United Kingdom
| | - Henk J Bolink
- Instituto de Ciencia Molecular, Universidad de Valencia , c/Catedrático J. Beltrán, 2, Paterna 46980, Spain
| | - Eli Zysman-Colman
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews , St Andrews, Fife KY16 9ST, United Kingdom
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Castilla AM, Miller MA, Nitschke JR, Smulders MMJ. Quantification of Stereochemical Communication in Metal-Organic Assemblies. Angew Chem Int Ed Engl 2016; 55:10616-20. [PMID: 27253388 PMCID: PMC5006869 DOI: 10.1002/anie.201602968] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 04/29/2016] [Indexed: 12/24/2022]
Abstract
The derivation and application of a statistical mechanical model to quantify stereochemical communication in metal-organic assemblies is reported. The factors affecting the stereochemical communication within and between the metal stereocenters of the assemblies were experimentally studied by optical spectroscopy and analyzed in terms of a free energy penalty per "incorrect" amine enantiomer incorporated, and a free energy of coupling between stereocenters. These intra- and inter-vertex coupling constants are used to track the degree of stereochemical communication across a range of metal-organic assemblies (employing different ligands, peripheral amines, and metals); temperature-dependent equilibria between diastereomeric cages are also quantified. The model thus provides a unified understanding of the factors that shape the chirotopic void spaces enclosed by metal-organic container molecules.
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Affiliation(s)
- Ana M Castilla
- Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Mark A Miller
- Department of Chemistry, Durham University, South Road, Durham, DH1 3LE, UK
| | | | - Maarten M J Smulders
- Laboratory of Organic Chemistry, Wageningen University, Stippeneng 4, 6708 WE, Wageningen, The Netherlands.
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Castilla AM, Miller MA, Nitschke JR, Smulders MMJ. Quantification of Stereochemical Communication in Metal-Organic Assemblies. ANGEWANDTE CHEMIE (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2016; 128:10774-10778. [PMID: 27656004 PMCID: PMC5012202 DOI: 10.1002/ange.201602968] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 04/29/2016] [Indexed: 11/22/2022]
Abstract
The derivation and application of a statistical mechanical model to quantify stereochemical communication in metal-organic assemblies is reported. The factors affecting the stereochemical communication within and between the metal stereocenters of the assemblies were experimentally studied by optical spectroscopy and analyzed in terms of a free energy penalty per "incorrect" amine enantiomer incorporated, and a free energy of coupling between stereocenters. These intra- and inter-vertex coupling constants are used to track the degree of stereochemical communication across a range of metal-organic assemblies (employing different ligands, peripheral amines, and metals); temperature-dependent equilibria between diastereomeric cages are also quantified. The model thus provides a unified understanding of the factors that shape the chirotopic void spaces enclosed by metal-organic container molecules.
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Affiliation(s)
- Ana M. Castilla
- Department of ChemistryUniversity of CambridgeCambridgeCB2 1EWUK
| | - Mark A. Miller
- Department of ChemistryDurham UniversitySouth RoadDurhamDH1 3LEUK
| | | | - Maarten M. J. Smulders
- Laboratory of Organic ChemistryWageningen UniversityStippeneng 46708 WEWageningenThe Netherlands
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35
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Malina J, Scott P, Brabec V. Recognition of DNA/RNA bulges by antimicrobial and antitumor metallohelices. Dalton Trans 2016. [PMID: 26212708 DOI: 10.1039/c5dt02018b] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Bulged structures have been identified in nucleic acids and have been shown to be linked to biomolecular processes involved in numerous diseases. Thus, chemical agents with affinity for bulged nucleic acids are of general biological significance. Herein, the mechanism of specific recognition and stabilization of bulged DNA and RNA by helical bimetallic species was established through detailed molecular biophysics and biochemistry assays. These agents, known as 'flexicates', are potential mimetics of α-helical peptides in cancer treatment, exhibiting antimicrobial and antitumor effects. The flexicates have positive impacts on the thermal stability of DNA duplexes containing bulges, which means that the flexicates interact with the duplexes containing bulges, and that these interactions stabilize the secondary structures of these duplexes. Notably, the stabilising effect of the flexicates increases with the size of the bulge, the maximal stabilization is observed for the duplexes containing a bulge composed of at least three bases. The flexicates bind most preferentially to the bulges composed of pyrimidines flanked on both sides also by pyrimidines. It is suggested that it is so because these bulges exhibit greatest conformational variability in comparison with other combinations of bases in the bulge loop and bases flanking the bulge. Finally, the results indicate that there is only one dominant binding site for the flexicates on the DNA and RNA bulges and that the flexicates bind directly to the bulge or in its close proximity. It is also shown that the flexicates effectively bind to RNA duplexes containing the bulged region of HIV-1 TAR RNA.
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Affiliation(s)
- Jaroslav Malina
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Kralovopolska 135, CZ-61265 Brno, Czech Republic.
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Stock P, Deck E, Hohnstein S, Korzekwa J, Meyer K, Heinemann FW, Breher F, Hörner G. Molecular Spin Crossover in Slow Motion: Light-Induced Spin-State Transitions in Trigonal Prismatic Iron(II) Complexes. Inorg Chem 2016; 55:5254-65. [PMID: 27159332 DOI: 10.1021/acs.inorgchem.6b00238] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A straightforward access is provided to iron(II) complexes showing exceedingly slow spin-state interconversion by utilizing trigonal-prismatic directing ligands (L(n)) of the extended-tripod type. A detailed analysis of the interrelations between complex structure (X-ray diffraction, density functional theory) and electronic character (SQUID magnetometry, Mössbauer spectroscopy, UV/vis spectroscopy) of the iron(II) center in mononuclear complexes [FeL(n)] reveals spin crossover to occur along a coupled breathing/torsion reaction coordinate, shuttling the complex between the octahedral low-spin state and the trigonal-prismatic high-spin state along Bailar's trigonal twist pathway. We associate both the long spin-state lifetimes in the millisecond domain close to room temperature and the substantial barriers against thermal scrambling (Ea ≈ 33 kJ mol(-1), from Arrhenius analysis) with stereochemical constraints. In particular, the topology of the κ(6)N ligands controls the temporary and structural dynamics during spin crossover.
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Affiliation(s)
- Philipp Stock
- Institut für Chemie, Technische Universität Berlin , Strasse des 17. Juni 135, 10623 Berlin, Germany
| | - Eva Deck
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT) , Engesserstrasse 15, 76131 Karlsruhe, Germany
| | - Silvia Hohnstein
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT) , Engesserstrasse 15, 76131 Karlsruhe, Germany
| | - Jana Korzekwa
- Department Chemie und Pharmazie, Anorganische Chemie, Friedrich-Alexander-Universität Erlangen-Nürnberg , Egerlandstraße 1, 91058 Erlangen, Germany
| | - Karsten Meyer
- Department Chemie und Pharmazie, Anorganische Chemie, Friedrich-Alexander-Universität Erlangen-Nürnberg , Egerlandstraße 1, 91058 Erlangen, Germany
| | - Frank W Heinemann
- Department Chemie und Pharmazie, Anorganische Chemie, Friedrich-Alexander-Universität Erlangen-Nürnberg , Egerlandstraße 1, 91058 Erlangen, Germany
| | - Frank Breher
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT) , Engesserstrasse 15, 76131 Karlsruhe, Germany
| | - Gerald Hörner
- Institut für Chemie, Technische Universität Berlin , Strasse des 17. Juni 135, 10623 Berlin, Germany
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Synthesis and biological evaluation of heterocyclic privileged medicinal structures containing (benz)imidazole unit. MONATSHEFTE FUR CHEMIE 2016. [DOI: 10.1007/s00706-016-1733-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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38
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39
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Hernández G, Bernès S, Portillo O, Ruíz A, Moreno GE, Gutiérrez R. Crystal structures of three mercury(II) complexes [HgCl2 L] where L is a bidentate chiral imine ligand. Acta Crystallogr E Crystallogr Commun 2015; 71:1462-6. [PMID: 26870405 PMCID: PMC4719814 DOI: 10.1107/s2056989015020368] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 10/28/2015] [Indexed: 11/30/2022]
Abstract
The crystal structures of three complexes [HgCl2 L] were determined, namely, (S)-(+)-di-chlorido-[1-phenyl-N-(pyridin-2-yl-methyl-idene)ethyl-amine-κ(2) N,N']mercury(II), [HgCl2(C14H14N2)], (S)-(+)-di-chlorido-[1-(4-methyl-phen-yl)-N-(pyridin-2-yl-methyl-idene)ethyl-amine-κ(2) N,N']mercury(II), [HgCl2(C15H16N2)], and (1S,2S,3S,5R)-(+)-di-chlorido-[N-(pyridin-2-yl-methyl-idene)isopino-camph-eyl-amine-κ(2) N,N']mercury(II), [HgCl2(C16H22N2)]. The complexes consist of a bidentate chiral imine ligand coordinating to HgCl2 and crystallize with four independent mol-ecules in the first complex and two independent mol-ecules in the other two. The coordination geometry of mercury is tetra-hedral, with strong distortion towards a disphenoidal geometry, as a consequence of the imine bite angle being close to 70°. The Cl-Hg-Cl angles span a large range, 116.0 (2)-138.3 (3)°, which is related to the aggregation state in the crystals. For small Cl-Hg-Cl angles, complexes have a tendency to form dimers, via inter-molecular Hg⋯Cl contacts. These contacts become less significant in the third complex, which features the largest intra-molecular Cl-Hg-Cl angles.
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Affiliation(s)
- Guadalupe Hernández
- Laboratorio de Síntesis de Complejos, Facultad de Ciencias Químicas, Universidad Autónoma de Puebla, A.P. 1067, 72001 Puebla, Pue., Mexico
| | - Sylvain Bernès
- Instituto de Física, Universidad Autónoma de Puebla, Av. San Claudio y 18 Sur, 72570 Puebla, Pue., Mexico
| | - Oscar Portillo
- Laboratorio de Síntesis de Complejos, Facultad de Ciencias Químicas, Universidad Autónoma de Puebla, A.P. 1067, 72001 Puebla, Pue., Mexico
| | - Alejandro Ruíz
- Departamento de Microbiología, Facultad de Ciencias Químicas, Universidad Autónoma de Puebla, Puebla, Pue., Mexico
| | - Gloria E. Moreno
- Laboratorio de Síntesis de Complejos, Facultad de Ciencias Químicas, Universidad Autónoma de Puebla, A.P. 1067, 72001 Puebla, Pue., Mexico
| | - René Gutiérrez
- Laboratorio de Síntesis de Complejos, Facultad de Ciencias Químicas, Universidad Autónoma de Puebla, A.P. 1067, 72001 Puebla, Pue., Mexico
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40
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Dabb SL, Fletcher NC. mer and fac isomerism in tris chelate diimine metal complexes. Dalton Trans 2015; 44:4406-22. [PMID: 25600485 DOI: 10.1039/c4dt03535f] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this perspective, we highlight the issue of meridional (mer) and facial (fac) orientation of asymmetrical diimines in tris-chelate transition metal complexes. Diimine ligands have long been the workhorse of coordination chemistry, and whilst there are now good strategies to isolate materials where the inherent metal centered chirality is under almost complete control, and systematic methodologies to isolate heteroleptic complexes, the conceptually simple geometrical isomerism has not been widely investigated. In systems where the two donor atoms are significantly different in terms of the σ-donor and π-accepting ability, the fac isomer is likely to be the thermodynamic product. For the diimine complexes with two trigonal planar nitrogen atoms there is much more subtlety to the system, and external factors such as the solvent, lattice packing and the various steric considerations play a delicate role in determining the observed and isolable product. In this article we discuss the possibilities to control the isomeric ratio in labile systems, consider the opportunities to separate inert complexes and discuss the observed differences in their spectroscopic properties. Finally we report on the ligand orientation in supramolecular systems where facial coordination leads to simple regular structures such as helicates and tetrahedra, but the ability of the ligand system to adopt a mer orientation enables self-assembled structures of considerable beauty and complexity.
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Affiliation(s)
- Serin L Dabb
- School of Chemistry and Chemical Engineering, Queen's University of Belfast, David Keir Building, Belfast, Northern Ireland BT9 5AG, UK.
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41
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Moegling J, Benischke AD, Hammann JM, Vepřek NA, Zoller F, Rendenbach B, Hoffmann A, Sievers H, Schuster M, Knochel P, Herres-Pawlis S. Bis(pyrazolyl)methane Copper Complexes as Robust and Efficient Catalysts for Sonogashira Couplings. European J Org Chem 2015. [DOI: 10.1002/ejoc.201501117] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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42
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Kaner RA, Allison SJ, Faulkner AD, Phillips RM, Roper DI, Shepherd SL, Simpson DH, Waterfield NR, Scott P. Anticancer metallohelices: nanomolar potency and high selectivity. Chem Sci 2015; 7:951-958. [PMID: 28808525 PMCID: PMC5530816 DOI: 10.1039/c5sc03677a] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 10/26/2015] [Indexed: 12/17/2022] Open
Abstract
New optically pure helicate-like architectures are extremely active against cancer cell lines, with IC50 values as low as 40 nM, but nearly three orders of magnitude less active against healthy cells. There is also low toxicity to microbes and amoeba.
A range of new helicate-like architectures have been prepared via highly diastereoselective self-assembly using readily accessible starting materials. Six pairs of enantiomers [Fe2L3]Cl4·nH2O (L = various bidentate ditopic ligands NN–NN) show very good water solubility and stability. Their activity against a range of cancer cell lines in vitro is structure-dependent and gives IC50 values as low as 40 nM. In an isogenic pair of HCT116 colorectal cancer cells, preferential activity was observed against cell lines that lack functional p53. Selectivity is also excellent, and against healthy human retinal pigment epithelial (ARPE19) and lung fibroblast (WI38) cells IC50 values are nearly three orders of magnitude higher. Cisplatin is unselective in the same tests. The compounds also appear to have low general toxicity in a number of models: there is little if any antimicrobial activity against methicillin-resistant Staphylococcus aureus and Escherichia coli; Acanthamoeba polyphaga is unaffected at 25 μg mL–1 (12.5 μM); Manduca sexta larvae showed clear evidence of systemic distribution of the drug, and rather than any observation of adverse effects they exhibited a significant mean weight gain vs. controls. Investigation of the mode of action revealed no significant interaction of the molecules with DNA, and stimulation of substantial cell death by apoptosis.
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Affiliation(s)
- Rebecca A Kaner
- Department of Chemistry , University of Warwick , Coventry , CV4 7AL , UK . .,Institute of Advanced Study , University of Warwick , CV4 7HS , UK
| | - Simon J Allison
- School of Applied Sciences , University of Huddersfield , Huddersfield , HD1 3DH , UK
| | - Alan D Faulkner
- Department of Chemistry , University of Warwick , Coventry , CV4 7AL , UK .
| | - Roger M Phillips
- School of Applied Sciences , University of Huddersfield , Huddersfield , HD1 3DH , UK
| | - David I Roper
- School of Life Sciences , University of Warwick , Coventry , CV4 7AL , UK
| | - Samantha L Shepherd
- School of Applied Sciences , University of Huddersfield , Huddersfield , HD1 3DH , UK
| | - Daniel H Simpson
- Department of Chemistry , University of Warwick , Coventry , CV4 7AL , UK . .,School of Life Sciences , University of Warwick , Coventry , CV4 7AL , UK
| | | | - Peter Scott
- Department of Chemistry , University of Warwick , Coventry , CV4 7AL , UK .
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43
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Wilfer C, Liebhäuser P, Hoffmann A, Erdmann H, Grossmann O, Runtsch L, Paffenholz E, Schepper R, Dick R, Bauer M, Dürr M, Ivanović-Burmazović I, Herres-Pawlis S. Efficient Biomimetic Hydroxylation Catalysis with a Bis(pyrazolyl)imidazolylmethane Copper Peroxide Complex. Chemistry 2015; 21:17639-49. [PMID: 26458073 DOI: 10.1002/chem.201501685] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Indexed: 11/08/2022]
Abstract
Bis(pyrazolyl)methane ligands are excellent components of model complexes used to investigate the activity of the enzyme tyrosinase. Combining the N donors 3-tert-butylpyrazole and 1-methylimidazole results in a ligand that is capable of stabilising a (μ-η(2) :η(2) )-dicopper(II) core that resembles the active centre of tyrosinase. UV/Vis spectroscopy shows blueshifted UV bands in comparison to other known peroxo complexes, due to donor competition from different ligand substituents. This effect was investigated with the help of theoretical calculations, including DFT and natural transition orbital analysis. The peroxo complex acts as a catalyst capable of hydroxylating a variety of phenols by using oxygen. Catalytic conversion with the non-biological phenolic substrate 8-hydroxyquinoline resulted in remarkable turnover numbers. In stoichiometric reactions, substrate-binding kinetics was observed and the intrinsic hydroxylation constant, kox , was determined for five phenolates. It was found to be the fastest hydroxylation model system determined so far, reaching almost biological activity. Furthermore, Hammett analysis proved the electrophilic character of the reaction. This sheds light on the subtle role of donor strength and its influence on hydroxylation activity.
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Affiliation(s)
- Claudia Wilfer
- Department für Chemie und Pharmazie, Ludwig-Maximilians-Universität München, Butenandtstraße 5-13, 81377 München (Germany).,Institut für Anorganische Chemie, Rheinisch-Westfälische Technische Hochschule Aachen, Landoltweg 1, 52074 Aachen (Germany)
| | - Patricia Liebhäuser
- Institut für Anorganische Chemie, Rheinisch-Westfälische Technische Hochschule Aachen, Landoltweg 1, 52074 Aachen (Germany)
| | - Alexander Hoffmann
- Institut für Anorganische Chemie, Rheinisch-Westfälische Technische Hochschule Aachen, Landoltweg 1, 52074 Aachen (Germany)
| | - Hannes Erdmann
- Department für Chemie und Pharmazie, Ludwig-Maximilians-Universität München, Butenandtstraße 5-13, 81377 München (Germany)
| | - Oleg Grossmann
- Department für Chemie und Pharmazie, Ludwig-Maximilians-Universität München, Butenandtstraße 5-13, 81377 München (Germany)
| | - Leander Runtsch
- Department für Chemie und Pharmazie, Ludwig-Maximilians-Universität München, Butenandtstraße 5-13, 81377 München (Germany)
| | - Eva Paffenholz
- Institut für Anorganische Chemie, Rheinisch-Westfälische Technische Hochschule Aachen, Landoltweg 1, 52074 Aachen (Germany)
| | - Rahel Schepper
- Department Chemie, Universität Paderborn, Warburger Straße 100, 33098 Paderborn (Germany)
| | - Regina Dick
- Department Chemie, Universität Paderborn, Warburger Straße 100, 33098 Paderborn (Germany)
| | - Matthias Bauer
- Department Chemie, Universität Paderborn, Warburger Straße 100, 33098 Paderborn (Germany)
| | - Maximilian Dürr
- Department Chemie und Pharmazie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 1, 91058 Erlangen (Germany)
| | - Ivana Ivanović-Burmazović
- Department Chemie und Pharmazie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 1, 91058 Erlangen (Germany)
| | - Sonja Herres-Pawlis
- Department für Chemie und Pharmazie, Ludwig-Maximilians-Universität München, Butenandtstraße 5-13, 81377 München (Germany). .,Institut für Anorganische Chemie, Rheinisch-Westfälische Technische Hochschule Aachen, Landoltweg 1, 52074 Aachen (Germany).
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Verevkin SP, Zaitseva KV, Stanton AD, Hindman MS, Irvin AC, Bara JE. Building Blocks for Ionic Liquids: Vapor Pressures and Vaporization Enthalpies of N-Functionalized Imidazoles with Branched and Cycloalkyl Substituents. Ind Eng Chem Res 2015. [DOI: 10.1021/acs.iecr.5b01599] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sergey P. Verevkin
- Department of Physical Chemistry and Department
“Science and Technology of Life, Light and Matter”, University of Rostock, D-18059 Rostock, Mecklenburg-Vorpommern, Germany
- Department
of Physical Chemistry, Kazan Federal University, 420008 Kazan, Russia
| | - Ksenia V. Zaitseva
- Department
of Physical Chemistry, Kazan Federal University, 420008 Kazan, Russia
| | - Alexander D. Stanton
- Department of Chemical & Biological Engineering, University of Alabama, Tuscaloosa, Alabama 35487-0203, United States
| | - Michelle S. Hindman
- Department of Chemical & Biological Engineering, University of Alabama, Tuscaloosa, Alabama 35487-0203, United States
| | - A. Christopher Irvin
- Department of Chemical & Biological Engineering, University of Alabama, Tuscaloosa, Alabama 35487-0203, United States
| | - Jason E. Bara
- Department of Chemical & Biological Engineering, University of Alabama, Tuscaloosa, Alabama 35487-0203, United States
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Malina J, Scott P, Brabec V. Shape-selective recognition of DNA abasic sites by metallohelices: inhibition of human AP endonuclease 1. Nucleic Acids Res 2015; 43:5297-306. [PMID: 25940617 PMCID: PMC4477665 DOI: 10.1093/nar/gkv438] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 04/23/2015] [Indexed: 02/07/2023] Open
Abstract
Loss of a base in DNA leading to creation of an abasic (AP) site leaving a deoxyribose residue in the strand, is a frequent lesion that may occur spontaneously or under the action of various physical and chemical agents. Progress in the understanding of the chemistry and enzymology of abasic DNA largely relies upon the study of AP sites in synthetic duplexes. We report here on interactions of diastereomerically pure metallo-helical 'flexicate' complexes, bimetallic triple-stranded ferro-helicates [Fe2(NN-NN)3](4+) incorporating the common NN-NN bis(bidentate) helicand, with short DNA duplexes containing AP sites in different sequence contexts. The results show that the flexicates bind to AP sites in DNA duplexes in a shape-selective manner. They preferentially bind to AP sites flanked by purines on both sides and their binding is enhanced when a pyrimidine is placed in opposite orientation to the lesion. Notably, the Λ-enantiomer binds to all tested AP sites with higher affinity than the Δ-enantiomer. In addition, the binding of the flexicates to AP sites inhibits the activity of human AP endonuclease 1, which is as a valid anticancer drug target. Hence, this finding indicates the potential of utilizing well-defined metallo-helical complexes for cancer chemotherapy.
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Affiliation(s)
- Jaroslav Malina
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Kralovopolska 135, CZ-61265 Brno, Czech Republic
| | - Peter Scott
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK
| | - Viktor Brabec
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Kralovopolska 135, CZ-61265 Brno, Czech Republic
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Qin LF, Pang CY, Han WK, Zhang FL, Tian L, Gu ZG, Ren X, Li Z. Optical recognition of alkyl nitrile by a homochiral iron(ii) spin crossover host. CrystEngComm 2015. [DOI: 10.1039/c5ce01617g] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this work, a chiral mononuclear spin crossover host1·MeCN was found to have the ability to optically recognize lactonitrile (LN) and methylglutaronitrile (MGN).
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Affiliation(s)
- Long-Fang Qin
- The Key Laboratory of Food Colloids and Biotechnology Ministry of Education
- School of Chemical and Material Engineering
- Jiangnan University
- Wuxi 214122, China
| | - Chun-Yan Pang
- The Key Laboratory of Food Colloids and Biotechnology Ministry of Education
- School of Chemical and Material Engineering
- Jiangnan University
- Wuxi 214122, China
| | - Wang-Kang Han
- The Key Laboratory of Food Colloids and Biotechnology Ministry of Education
- School of Chemical and Material Engineering
- Jiangnan University
- Wuxi 214122, China
| | - Feng-Li Zhang
- The Key Laboratory of Food Colloids and Biotechnology Ministry of Education
- School of Chemical and Material Engineering
- Jiangnan University
- Wuxi 214122, China
| | - Lei Tian
- The Key Laboratory of Food Colloids and Biotechnology Ministry of Education
- School of Chemical and Material Engineering
- Jiangnan University
- Wuxi 214122, China
| | - Zhi-Guo Gu
- The Key Laboratory of Food Colloids and Biotechnology Ministry of Education
- School of Chemical and Material Engineering
- Jiangnan University
- Wuxi 214122, China
| | - Xuehong Ren
- The Key Laboratory of Eco-textiles of Ministry of Education
- College of Textiles and Clothing
- Jiangnan University
- Wuxi 214122, China
| | - Zaijun Li
- The Key Laboratory of Food Colloids and Biotechnology Ministry of Education
- School of Chemical and Material Engineering
- Jiangnan University
- Wuxi 214122, China
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Yang Y, Jia JH, Pei XL, Zheng H, Nan ZA, Wang QM. Diastereoselective synthesis of O symmetric heterometallic cubic cages. Chem Commun (Camb) 2015; 51:3804-7. [DOI: 10.1039/c5cc00087d] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Enantiopure chiral cubic cages have been diastereoselectively synthesized, showing CD enhancement as a result of configuration rigidity.
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Affiliation(s)
- Yang Yang
- State Key Lab of Physical Chemistry of Solid Surfaces
- Collaborative Innovation Center of Chemistry for Energy Materials (iChEM)
- Department of Chemistry
- College of Chemistry and Chemical Engineering
- Xiamen University
| | - Jian-Hua Jia
- School of Chemistry & Chemical Engineering
- Sun Yat-Sen University
- Guangzhou
- People's Republic of China
| | - Xiao-Li Pei
- State Key Lab of Physical Chemistry of Solid Surfaces
- Collaborative Innovation Center of Chemistry for Energy Materials (iChEM)
- Department of Chemistry
- College of Chemistry and Chemical Engineering
- Xiamen University
| | - Hao Zheng
- State Key Lab of Physical Chemistry of Solid Surfaces
- Collaborative Innovation Center of Chemistry for Energy Materials (iChEM)
- Department of Chemistry
- College of Chemistry and Chemical Engineering
- Xiamen University
| | - Zi-Ang Nan
- State Key Lab of Physical Chemistry of Solid Surfaces
- Collaborative Innovation Center of Chemistry for Energy Materials (iChEM)
- Department of Chemistry
- College of Chemistry and Chemical Engineering
- Xiamen University
| | - Quan-Ming Wang
- State Key Lab of Physical Chemistry of Solid Surfaces
- Collaborative Innovation Center of Chemistry for Energy Materials (iChEM)
- Department of Chemistry
- College of Chemistry and Chemical Engineering
- Xiamen University
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Jena HS. Effect of steric congestion and non-covalent interaction on the self-organization of two isostructural 1D chiral coordination polymers. Inorganica Chim Acta 2014. [DOI: 10.1016/j.ica.2014.05.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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