Mechanistic Aspects of the Photosubstitution and Photoisomerization Reactions of
            <i>d</i>
            <sup>6</sup>
            Metal Complexes

Ford, Peter C.; Wink, David A.; DiBenedetto, John

doi:10.1002/9780470166314.ch5

Cited by 84 publications

(57 citation statements)

References 153 publications

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“…However, all show broad, structureless emission when examined at 77 K in rigid water–methanol glass. It is known that the initially generated singlet‐excited states of these complexes rapidly intersystem cross and internally convert into a lowest‐lying 3 (d‐d) state (34–36) and the emission we observe is characteristic of 3 (d‐d) states (37). Both the room temperature photosubstitution chemistry and the low temperature phosphorescence arise from these states (38–41).…”

Section: Resultsmentioning

confidence: 76%

Effect of Ring Methylation on the Photophysical, Photochemical and Photobiological Properties of cis-Dichlorobis(1,10-Phenanthroline)Rhodium(III)Chloride†

Loganathan

Morrison

2006

Photochem Photobiol

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Methylated analogues of cis-dichlorobis(1,10-phenanthroline)rhodium(III)chloride (BISPHEN) have been prepared in order to increase the hydrophobicity of the parent compound, and thus create octahedral rhodium (III) complexes suitable for use as anticancer and antiviral agents that can be photoactivated. The parent complex has been shown in earlier work to be unable to cross through cell membranes. Octamethylation, as in the case of cis-dichlorobis(3,4,7,8-tetramethyl-1,10-phenanthroline)rhodium(III)chloride (OCTBP), provides enough hydrophobicity to be taken up by KB tumor cells. It also provides a higher level of ground-state association with double-stranded DNA and increases the quantum efficiency of photoaquation by greater than 10-fold, relative to BISPHEN. OCTBP forms covalent bonds to deoxyguanosine when irradiated with the nucleoside, as has been seen with the parent complex. Irradiation of OCTBP in the presence of the KB or M109 tumor cell lines using narrow-band UVB (lambda = 311 nm) irradiation initiates a considerable amount of phototoxicity. There is evidence that OCTBP acts as a prodrug (i.e. after passing through the cell membrane the metal complex is photolyzed to cis-chloro aquo OCTBP, which may be the active phototoxic agent). OCTBP and the tetramethyl analogue cis-dichlorobis(4,7-dimethyl-1,10-phenanthroline)rhodium(III)chloride (47TMBP) also show photoaquation upon excitation with visible light (lambda > 500 nm), and indeed, some phototoxicity of KB cells is observed at these wavelengths as well. This is attributed to direct population of photoactive triplet-excited states. These results, together with our earlier studies of cis-dichloro[dipyrido(3,2-a: 2',3'-c)phenazine (1,10-phenanthroline)rhodium(III)chloride (DPPZPHEN) demonstrate that such octahedral rhodium complexes are viable "photo-cisplatin" reagents.

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Section: Resultsmentioning

confidence: 76%

Effect of Ring Methylation on the Photophysical, Photochemical and Photobiological Properties of cis-Dichlorobis(1,10-Phenanthroline)Rhodium(III)Chloride†

Loganathan

Morrison

2006

Photochem Photobiol

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“…However, CO photolability occurs primarily from metal-centered ligand field states. 151 Substituents can be used to tune the MLCT absorptions of the Re( i ) complexes to the red, but excitation at those longer wavelength bands does not lead to significant CO release, since this does not populate the higher-energy MC states necessary for CO labilization. In fact, the story is quite analogous to the photoreactivity of the Ru(NH 3 ) 5 (L) 2+ complexes discussed above.…”

Section: Applying What We Know and Learning New Tricks: Photochemicalmentioning

confidence: 99%

From curiosity to applications. A personal perspective on inorganic photochemistry

Ford

2016

Chem. Sci.

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“…Ru(II) polypyridyl complexes are attractive systems for the development of light-mediated biologically active compounds. Their photophysical and photochemical properties have been studied extensively over the years (7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22), and they have proven success as light-responsive prodrugs for PDT (23,24) and photochemotherapy (PCT) (25)(26)(27)(28)(29)(30)(31)(32). The premise behind these phototherapies is that the initial metal complex serves as a relatively nontoxic compound that can be activated by light to become a powerful cytotoxin with high spatiotemporal selectivity for tumors.…”

Section: Introductionmentioning

confidence: 99%

Strained, Photoejecting Ru(II) Complexes that are Cytotoxic Under Hypoxic Conditions

Roque

Havrylyuk

Barrett

et al. 2019

Photochem & Photobiology

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A series of strained Ru(II) complexes were studied for potential anticancer activity in hypoxic tissues. The complexes were constructed with methylated ligands that were photolabile and an imidizo[4,5‐f][1,10]phenanthroline ligand that contained an appended aromatic group to potentially allow for contributions of ligand‐centered excited states. A systematic variation of the size and energy of the aromatic group was performed using systems containing 1–4 fused rings, and the photochemical and photobiological behaviors of all complexes were assessed. The structure and nature of the aromatic group had a subtle impact on photochemistry, altering environmental sensitivity, and had a significant impact on cellular cytotoxicity and photobiology. Up to 5‐fold differences in cytotoxicity were observed in the absence of light activation; this rose to 50‐fold differences upon exposure to 453 nm light. Most significantly, one complex retained activity under conditions with 1% O2, which is used to induce hypoxic changes. This system exhibited a photocytotoxicity index (PI) of 15, which is in marked contrast to most other Ru(II) complexes, including those designed for O2‐independent mechanisms of action.

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Mechanistic Aspects of the Photosubstitution and Photoisomerization Reactions of d ⁶ Metal Complexes

Cited by 84 publications

References 153 publications

Effect of Ring Methylation on the Photophysical, Photochemical and Photobiological Properties of cis-Dichlorobis(1,10-Phenanthroline)Rhodium(III)Chloride†

Effect of Ring Methylation on the Photophysical, Photochemical and Photobiological Properties of cis-Dichlorobis(1,10-Phenanthroline)Rhodium(III)Chloride†

From curiosity to applications. A personal perspective on inorganic photochemistry

Strained, Photoejecting Ru(II) Complexes that are Cytotoxic Under Hypoxic Conditions

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Mechanistic Aspects of the Photosubstitution and Photoisomerization Reactions of d 6 Metal Complexes

Cited by 84 publications

References 153 publications

Effect of Ring Methylation on the Photophysical, Photochemical and Photobiological Properties of cis-Dichlorobis(1,10-Phenanthroline)Rhodium(III)Chloride†

Effect of Ring Methylation on the Photophysical, Photochemical and Photobiological Properties of cis-Dichlorobis(1,10-Phenanthroline)Rhodium(III)Chloride†

From curiosity to applications. A personal perspective on inorganic photochemistry

Strained, Photoejecting Ru(II) Complexes that are Cytotoxic Under Hypoxic Conditions

Contact Info

Product

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Mechanistic Aspects of the Photosubstitution and Photoisomerization Reactions of d ⁶ Metal Complexes