Adenine Radical Cation Formation by a Ligand-Centered Excited State of an Intercalated Chromium Polypyridyl Complex Leads to Enhanced DNA Photo-oxidation (65 views)
J Am Chem Soc (ISSN: 0002-7863linking, 0002-7863print), 2021 Sep 15; 143(36): 14766-14779.
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Paper type: Journal Article,
Impact factor: 15.419, 5-year impact factor: 8.981
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Affiliations:
*** IBB - CNR ***
School of Chemistry, University College Dublin, Dublin 4, Ireland.
STFC Central Laser Facility, Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Campus, Didcot, OX11 0QX, U.K.
The School of Chemical Sciences, Dublin City University, Dublin 9, Ireland.
Departamento de Química, Facultad de Ciencias and Institute for Advanced Research in Chemistry(IADCHEM) Universidad Autónoma de Madrid, Campus de Excelencia UAM-CSIC, Cantoblanco, 28049 Madrid, Spain.
Consiglio Nazionale delle Ricerche, Istituto di Biostrutture e Bioimmagini, 80136 Naples, Italy.
Department of Chemistry, Furman University, 3300 Poinsett Highway, Greenville, South Carolina 29613-1120, United States.
References:
Not available.
J Am Chem Soc (ISSN: 0002-7863linking, 0002-7863print), 2021 Sep 15; 143(36): 14766-14779.
Export to BibTeX Export to EndNote
Paper type: Journal Article,
Impact factor: 15.419, 5-year impact factor: 8.981
Url: Not available.
Keywords: Not available.
Affiliations:
*** IBB - CNR ***
School of Chemistry, University College Dublin, Dublin 4, Ireland.
STFC Central Laser Facility, Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Campus, Didcot, OX11 0QX, U.K.
The School of Chemical Sciences, Dublin City University, Dublin 9, Ireland.
Departamento de Química, Facultad de Ciencias and Institute for Advanced Research in Chemistry(IADCHEM) Universidad Autónoma de Madrid, Campus de Excelencia UAM-CSIC, Cantoblanco, 28049 Madrid, Spain.
Consiglio Nazionale delle Ricerche, Istituto di Biostrutture e Bioimmagini, 80136 Naples, Italy.
Department of Chemistry, Furman University, 3300 Poinsett Highway, Greenville, South Carolina 29613-1120, United States.
References:
Not available.
Adenine Radical Cation Formation by a Ligand-Centered Excited State of an Intercalated Chromium Polypyridyl Complex Leads to Enhanced DNA Photo-oxidation
Assessment of the DNA photo-oxidation and synthetic photocatalytic activity of chromium polypyridyl complexes is dominated by consideration of their long-lived metal-centered excited states. Here we report the participation of the excited states of [Cr(TMP)(2)dppz](3+) (1) (TMP = 3,4,7,8-tetramethyl-1,10-phenanthroline; dppz = dipyrido[3,2-a:2',3'-c]phenazine) in DNA photoreactions. The interactions of enantiomers of 1 with natural DNA or with oligodeoxynucleotides with varying AT content (0-100%) have been studied by steady state UV/visible absorption and luminescence spectroscopic methods, and the emission of 1 is found to be quenched in all systems. The time-resolved infrared (TRIR) and visible absorption spectra (TA) of 1 following excitation in the region between 350 to 400 nm reveal the presence of relatively long-lived dppz-centered states which eventually yield the emissive metal-centered state. The dppz-localized states are fully quenched when bound by GC base pairs and partially so in the presence of an AT base-pair system to generate purine radical cations. The sensitized formation of the adenine radical cation species (A(•+)T) is identified by assigning the TRIR spectra with help of DFT calculations. In natural DNA and oligodeoxynucleotides containing a mixture of AT and GC of base pairs, the observed time-resolved spectra are consistent with eventual photo-oxidation occurring predominantly at guanine through hole migration between base pairs. The combined targeting of purines leads to enhanced photo-oxidation of guanine. These results show that DNA photo-oxidation by the intercalated 1, which locates the dppz in contact with the target purines, is dominated by the LC centered excited state. This work has implications for future phototherapeutics and photocatalysis.
Assessment of the DNA photo-oxidation and synthetic photocatalytic activity of chromium polypyridyl complexes is dominated by consideration of their long-lived metal-centered excited states. Here we report the participation of the excited states of [Cr(TMP)(2)dppz](3+) (1) (TMP = 3,4,7,8-tetramethyl-1,10-phenanthroline; dppz = dipyrido[3,2-a:2',3'-c]phenazine) in DNA photoreactions. The interactions of enantiomers of 1 with natural DNA or with oligodeoxynucleotides with varying AT content (0-100%) have been studied by steady state UV/visible absorption and luminescence spectroscopic methods, and the emission of 1 is found to be quenched in all systems. The time-resolved infrared (TRIR) and visible absorption spectra (TA) of 1 following excitation in the region between 350 to 400 nm reveal the presence of relatively long-lived dppz-centered states which eventually yield the emissive metal-centered state. The dppz-localized states are fully quenched when bound by GC base pairs and partially so in the presence of an AT base-pair system to generate purine radical cations. The sensitized formation of the adenine radical cation species (A(•+)T) is identified by assigning the TRIR spectra with help of DFT calculations. In natural DNA and oligodeoxynucleotides containing a mixture of AT and GC of base pairs, the observed time-resolved spectra are consistent with eventual photo-oxidation occurring predominantly at guanine through hole migration between base pairs. The combined targeting of purines leads to enhanced photo-oxidation of guanine. These results show that DNA photo-oxidation by the intercalated 1, which locates the dppz in contact with the target purines, is dominated by the LC centered excited state. This work has implications for future phototherapeutics and photocatalysis.
Adenine Radical Cation Formation by a Ligand-Centered Excited State of an Intercalated Chromium Polypyridyl Complex Leads to Enhanced DNA Photo-oxidation
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