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Eastham K, Kennedy ADW, Scottwell SØ, Bramham JE, Hardman S, Golovanov AP, Scattergood PA, Crowley JD, Elliott PIP. Photochemistry of Ru(II) Triazole Complexes with 6-Membered Chelate Ligands: Detection and Reactivity of Ligand-Loss Intermediates. Inorg Chem 2024; 63:9084-9097. [PMID: 38701516 PMCID: PMC11110011 DOI: 10.1021/acs.inorgchem.4c00251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 04/19/2024] [Accepted: 04/23/2024] [Indexed: 05/05/2024]
Abstract
Photochemical ligand release from metal complexes may be exploited in the development of novel photoactivated chemotherapy agents for the treatment of cancer and other diseases. Highly intriguing photochemical behavior is reported for two ruthenium(II) complexes bearing conformationally flexible 1,2,3-triazole-based ligands incorporating a methylene spacer to form 6-membered chelate rings. [Ru(bpy)2(pictz)]2+ (1) and [Ru(bpy)2(btzm)]2+ (2) (bpy = 2,2'-bipyridyl; pictz = 1-(picolyl)-4-phenyl-1,2,3-triazole; btzm = bis(4-phenyl-1,2,3-triazol-4-yl)methane) exhibit coordination by the triazole ring through the less basic N2 atom as a consequence of chelation and readily undergo photochemical release of the pictz and btzm ligands (ϕ = 0.079 and 0.091, respectively) in acetonitrile solution to form cis-[Ru(bpy)2(NCMe)2]2+ (3) in both cases. Ligand-loss intermediates of the form [Ru(bpy)2(κ1-pictz or κ1-btzm)(NCCD3)]2+ are detected by 1H NMR spectroscopy and mass spectrometry. Photolysis of 1 yields three ligand-loss intermediates with monodentate pictz ligands, two of which form through simple decoordination of either the pyridine or triazole donor with subsequent solvent coordination (4-tz(N2) and 4-py, respectively). The third intermediate, shown to be able to form photochemically directly from 1, arises through linkage isomerism in which the monodentate pictz ligand is coordinated by the triazole N3 atom (4-tz(N3)) with a comparable ligand-loss intermediate with an N3-bound κ1-btzm ligand also observed for 2.
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Affiliation(s)
- Katie Eastham
- Department
of Chemical Sciences and Centre for Functional Materials, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K.
| | - Aaron D. W. Kennedy
- Department
of Chemistry, University of Otago, PO Box 56, Dunedin 9054, New Zealand
- MacDiarmid
Institute for Advanced Materials and Nanotechnology, Wellington 6140, New Zealand
| | - Synøve Ø. Scottwell
- Department
of Chemistry, University of Otago, PO Box 56, Dunedin 9054, New Zealand
- MacDiarmid
Institute for Advanced Materials and Nanotechnology, Wellington 6140, New Zealand
| | - Jack E. Bramham
- Department
of Chemistry, School of Natural Sciences, Faculty of Science and Engineering, The University of Manchester, Manchester M13 9PL, U.K.
| | - Samantha Hardman
- Manchester
Institute of Biotechnology, The University
of Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
| | - Alexander P. Golovanov
- Department
of Chemistry, School of Natural Sciences, Faculty of Science and Engineering, The University of Manchester, Manchester M13 9PL, U.K.
| | - Paul A. Scattergood
- Department
of Chemical Sciences and Centre for Functional Materials, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K.
| | - James D. Crowley
- Department
of Chemistry, University of Otago, PO Box 56, Dunedin 9054, New Zealand
- MacDiarmid
Institute for Advanced Materials and Nanotechnology, Wellington 6140, New Zealand
| | - Paul I. P. Elliott
- Department
of Chemical Sciences and Centre for Functional Materials, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K.
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Margaret McCutcheon M, Freindorf M, Kraka E. Bonding in Nitrile Photo-dissociating Ruthenium Drug Candidates --A Local Vibrational Mode Study. J Chem Phys 2022; 157:014301. [DOI: 10.1063/5.0094567] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In this work, we investigated bonding features 15 ruthenium complexes of the type [Ru(tpy)(L)-(CH3CN)]n+, containing the tridentate tpy ligand (tpy = 2,2':6',2'--terpyridine) and various bidentate ancillary ligands, 12 compounds originally synthesized by Loftus et al. (J. Phys. Chem. C 123, 10291-10299 (2019)) complemented with three additional complexes. The main focus of our work was to relate these local features to the experimental data of Loftus et al. which assess the efficiency of nitrile release in an indirect way via observed quantum yields for ruthenium water association after nitrile release. As a tool to quantitatively assess Ru-NC and Ru-L bonding we utilized the local vibrational mode analysis complemented by the topological analysis of the electron density and the natural bond orbital analysis. Interestingly, the stronger Ru-NC bonds have the greater observed quantum yields, leading to the conclusion that the observed quantum yields are a result of a complex interplay of several processes excluding a direct relationship between QY and Ru-NC or Ru-L bond strengths. We identified the ST splitting as one of the key players and not the Ru-NC bond strength, as one may have thought. In summary, this work has presented a modern computational tool set for the investigation of bonding features applied to nitrile photo-dissociating ruthenium drug candidates forming a valuable basis for future design and fine tuning of nitrile releasing ruthenium compounds, as well as for the understanding of how local properties affect overall experimental outcomes.
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Affiliation(s)
| | | | - Elfi Kraka
- Chemistry, Southern Methodist University, United States of America
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Benniston AC, Zeng L. Recent Advances in Photorelease Complexes for Therapeutic Applications”. Dalton Trans 2022; 51:4202-4212. [DOI: 10.1039/d2dt00254j] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Photorelease complexes represent a class of agents for which UV-visible light triggers the expulsion of a specfic molecule that is intrinsically part of the inner coordination sphere or held in...
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