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Synthesis and Characterization of Iridium(III) Cyclometalated Complexes with Oligonucleotides: Insights into Redox Reactions with DNA

Shao, Fangwei and Elias, Benjamin and Lu, Wei and Barton, Jacqueline K. (2007) Synthesis and Characterization of Iridium(III) Cyclometalated Complexes with Oligonucleotides: Insights into Redox Reactions with DNA. Inorganic Chemistry, 46 (24). pp. 10187-10199. ISSN 0020-1669. doi:10.1021/ic7014012.

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Heteroleptic cyclometalated complexes of Ir(III) containing the dipyridophenazine ligand are synthesized through the direct introduction of a functionalized dipyridophenazine ligand onto a bis(dichloro)-bridged Ir(III) precusor and characterized by ^1H NMR, mass spectrometry, as well as spectroscopic and electrochemical properties. The excited state of the Ir(III) complexes have sufficient driving force to oxidize purines and to reduce pyrimidine nucleobases. Luminescence and EPR measurements of the Ir(III) complex with an unmodified dppz bound to DNA show the formation of a guanine radical upon irradiation, resulting from an oxidative photoinduced electron-transfer process. Evidence is also obtained indirectly for reductive photoinduced electron transfer from the excited complex to the thymine base in DNA. We have also utilized cyclopropylamine-substituted nucleosides as ultrafast kinetic traps to report transient charge occupancy in oligonucleotides when DNA is irradiated in the presence of noncovalently bound complexes. These experiments establish that the derivatized Ir(III) complexes, with photoactivation, can trigger the oxidation of guanine and the reduction of cytosine.

Item Type:Article
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URLURL TypeDescription ItemSupporting Information
Shao, Fangwei0000-0003-2007-3920
Elias, Benjamin0000-0001-5037-3313
Barton, Jacqueline K.0000-0001-9883-1600
Additional Information:© 2007 American Chemical Society. Received July 13, 2007. Publication Date (Web): October 31, 2007. We are grateful to the NIH for their financial support. B.E. also thanks the Département des Relations Internationales de l’Université Libre de Bruxelles (Prix Rayonnement International) and the Fondation L. de Bay for postdoctoral fellowships.
Funding AgencyGrant Number
Université Libre de BruxellesUNSPECIFIED
Fondation L. de BayUNSPECIFIED
Issue or Number:24
Record Number:CaltechAUTHORS:20160229-073228331
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Official Citation:Synthesis and Characterization of Iridium(III) Cyclometalated Complexes with Oligonucleotides:  Insights into Redox Reactions with DNA Fangwei Shao, Benjamin Elias, Wei Lu, and Jacqueline K. Barton Inorganic Chemistry 2007 46 (24), 10187-10199 DOI: 10.1021/ic7014012
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:64831
Deposited By: Ruth Sustaita
Deposited On:29 Feb 2016 18:02
Last Modified:10 Nov 2021 23:35

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