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De Rosa DF, Starck M, Parker D, Pal R. Unlocking same-sign CPL: solvent effects on spectral form and racemisation kinetics in nine-coordinate chiral europium(III) complexes. Chemistry 2023:e202303227. [PMID: 38078726 DOI: 10.1002/chem.202303227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Indexed: 12/22/2023]
Abstract
Understanding the factors that shape the circularly polarised luminescence (CPL) emission profiles of europium(III)-based CPL emitters to have specific sign properties, e. g. monosignate individual CPL transitions, is key to design novel complexes for applications ranging from advanced security inks to bio-probes for live cell imaging. In order to correlate structure and spectral characteristics, a photophysical and kinetic investigation has been conducted on a series of coordinatively saturated nine-coordinate europium(III) systems based on 1,4,7-triazacyclononane. We highlight that lanthanide emission is sensitive to changes in the ligand field by showing the linear dependence of total emission intensity ratios as a function of solvent polarity, for europium(III) complexes displaying an internal charge transfer (ICT) excited state. This sensitivity increases by a factor of 20 when studying changes in CPL spectra, rendering these complexes accurate probes of local polarity. Solvent polarity, solvent-specific effects, and the nature of the chromophores' coordinating donor atoms strongly influence the kinetic stability of europium(III) complexes with respect to enantiomer interconversion. Notably, we show that the choice of donor groups to coordinating to europium(III) and the nature and polarity of the solvent affects the rate of racemisation, leading to systems with very long half-lives at room temperature in non-polar media.
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Affiliation(s)
- Davide F De Rosa
- Department of Chemistry, Durham University, South Road, Durham, DH1 3LE, UK
| | - Matthieu Starck
- Department of Chemistry, Durham University, South Road, Durham, DH1 3LE, UK
| | - David Parker
- Department of Chemistry, Durham University, South Road, Durham, DH1 3LE, UK
- Current address: Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong
| | - Robert Pal
- Department of Chemistry, Durham University, South Road, Durham, DH1 3LE, UK
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Marcinkowski D, Kubicki M, Patroniak V, Muzioł T, Chorazy S, Shi L, Zychowicz M, Majcher-Fitas AM, Podgajny R, Gorczyński A. Trityl-Based Lanthanide-Supramolecular Assemblies Exhibiting Slow Magnetic Relaxation. Chemistry 2023; 29:e202300695. [PMID: 37408381 DOI: 10.1002/chem.202300695] [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: 03/03/2023] [Revised: 06/26/2023] [Accepted: 07/03/2023] [Indexed: 07/07/2023]
Abstract
The triphenylmethane (trityl) group has been recognized as a supramolecular synthon in crystal engineering, molecular machine rotors and stereochemical chirality inductors in materials science. Herein we demonstrate for the first time how it can be utilized in the domain of molecular magnetic materials through shaping of single molecule magnet (SMM) properties within the lanthanide complexes in tandem with other non-covalent interactions. Trityl-appended mono- (HL1 ) and bis-compartmental (HL2 ) hydrazone ligands were synthesized and complexated with Dy(III) and Er(III) triflate and nitrate salts to generate four monometallic (1-4) and two bimetallic (5, 6) complexes. The static and dynamic magnetic properties of 1-6 were investigated, revealing that only ligand HL1 induces assemblies (1-4) capable of showing SMM behaviour, with Dy(III) congeners (1, 2) able to exhibit the phenomenon also under zero field conditions. Theoretical ab initio studies helped in determination of Dy(III) energetic levels, magnetic anisotropic axes and corroborated magnetic relaxation mechanisms to be a combination of Raman and quantum tunnelling in zero dc field, the latter being cancelled in the optimum non-zero dc field. Our work represents the first study of magneto-structural correlations within the trityl Ln-SMMs, leading to generation of slowly relaxing zero-field dysprosium complexes within the hydrogen-bonded assemblies.
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Affiliation(s)
- Dawid Marcinkowski
- Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61-614, Poznań, Poland
| | - Maciej Kubicki
- Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61-614, Poznań, Poland
| | - Violetta Patroniak
- Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61-614, Poznań, Poland
| | - Tadeusz Muzioł
- Nicolaus Copernicus University in Torun, Faculty of Chemistry, Jurija Gagarina 11, 87-100, Toruń, Poland
| | - Szymon Chorazy
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387, Kraków, Poland
| | - Le Shi
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387, Kraków, Poland
| | - Mikołaj Zychowicz
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387, Kraków, Poland
| | - Anna M Majcher-Fitas
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, Łojasiewicza 11, 30-348, Kraków, Poland
| | - Robert Podgajny
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387, Kraków, Poland
| | - Adam Gorczyński
- Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61-614, Poznań, Poland
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New N4-Donor Ligands as Supramolecular Guests for DNA and RNA: Synthesis, Structural Characterization, In Silico, Spectrophotometric and Antimicrobial Studies. MOLECULES (BASEL, SWITZERLAND) 2023; 28:molecules28010400. [PMID: 36615615 PMCID: PMC9823393 DOI: 10.3390/molecules28010400] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 12/22/2022] [Accepted: 12/26/2022] [Indexed: 01/05/2023]
Abstract
The present work reports the synthesis of new N4-donor compounds carrying p-xylyl spacers in their structure. Different Schiff base aliphatic N-donors were obtained synthetically and subsequently evaluated for their ability to interact with two models of nucleic acids: calf-thymus DNA (CT-DNA) and the RNA from yeast Saccharomyces cerevisiae (herein simply indicated as RNA). In more detail, by condensing p-xylylenediamine and a series of aldehydes, we obtained the following Schiff base ligands: 2-thiazolecarboxaldehyde (L1), pyridine-2-carboxaldehyde (L2), 5-methylisoxazole-3-carboxaldehyde (L3), 1-methyl-2-imidazolecarboxaldehyde (L4), and quinoline-2-carboxaldehyde (L5). The structural characterisation of the ligands L1-L5 (X-ray, 1H NMR, 13C NMR, elemental analysis) and of the coordination polymers {[CuL1]PF6}n (herein referred to as Polymer1) and {[AgL1]BF4}n, (herein referred to as Polymer2, X-ray, 1H NMR, ESI-MS) is herein described in detail. The single crystal X-ray structures of complexes Polymer1 and Polymer2 were also investigated, leading to the description of one-dimensional coordination polymers. The spectroscopic and in silico evaluation of the most promising compounds as DNA and RNA binders, as well as the study of the influence of the 1D supramolecular polymers Polymer1 and Polymer2 on the proliferation of Escherichia coli bacteria, were performed in view of their nucleic acid-modulating and antimicrobial applications. Spectroscopic measurements (UV-Vis) combined with molecular docking calculations suggest that the thiazolecarboxaldehyde derivative L1 is able to bind CT-DNA with a mechanism different from intercalation involving the thiazole ring in the molecular recognition and shows a binding affinity with DNA higher than RNA. Finally, Polymer2 was shown to slow down the proliferation of bacteria much more effectively than the free Ag(I) salt.
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