Solvent dependent photophysics of fac-[Re(CO)3(11,12-X2dppz)(py)]+ (X = H, F or Me)

Dyer, Joanne; Creely, Caitriona M.; Penedo, J. Carlos; Grills, David C.; Hudson, Sarah A.; Matousek, Pavel; Parker, Anthony W.; Towrie, Michael; Kelly, John M.; George, Michael W.

doi:10.1039/b618651c

Cited by 30 publications

(37 citation statements)

References 33 publications

(25 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Variation of the N,N and L ligands affords fine control over the excited-state characters and energetics. 16,18–20,22–27 These complexes have also proven useful as biochemical probes for fluorescence imaging, 28 for monitoring the dynamics of structural fluctuations, 29,30 and especially, for triggering photoinduced electron transfer (ET). 31 Information on ET kinetics and intermediates provided by TRIR is more direct than that obtained using UV/visible time-resolved spectroscopic methods due to their low specificity.…”

Section: Introductionmentioning

confidence: 99%

Charge Photoinjection in Intercalated and Covalently Bound [Re(CO)₃(dppz)(py)]⁺–DNA Constructs Monitored by Time-Resolved Visible and Infrared Spectroscopy

et al. 2011

Self Cite

View full text Add to dashboard Cite

The complex [Re(CO)3(dppz)(py′-OR)]+ (dppz = dipyrido[3,2-a:2′,3′-c]phenazine; py′-OR = 4-functionalized pyridine) offers IR sensitivity and can oxidize DNA directly from the excited state, making it a promising probe for the study of DNA-mediated charge transport (CT). The behavior of several covalent and noncovalent Re-DNA constructs was monitored by time-resolved IR (TRIR) and UV/visible spectroscopies, as well as biochemical methods, confirming the long-range oxidation of DNA by the excited complex. Optical excitation of the complex leads to population of MLCT and at least two distinct intraligand states. Experimental observations that are consistent with charge injection from these excited states include similarity between long-time TRIR spectra and the reduced state spectrum observed by spectroelectrochemistry, the appearance of a guanine radical signal in TRIR spectra, and the eventual formation of permanent guanine oxidation products. The majority of reactivity occurs on the ultrafast timescale, although processes dependent on slower conformational motions of DNA, such as the accumulation of oxidative damage at guanine, are also observed. The ability to measure events on such disparate timescales, its superior selectivity in comparison to other spectroscopic techniques, and the ability to simultaneously monitor carbonyl ligand and DNA IR absorption bands makes TRIR a valuable tool for the study of CT in DNA.

show abstract

Section: Introductionmentioning

confidence: 99%

Charge Photoinjection in Intercalated and Covalently Bound [Re(CO)₃(dppz)(py)]⁺–DNA Constructs Monitored by Time-Resolved Visible and Infrared Spectroscopy

et al. 2011

Self Cite

View full text Add to dashboard Cite

show abstract

“…This behaviour contrasts with their counterparts [Ru(phen) 2 (dppz)] 2+ 12,18 and [Re(CO) 3 (F 2 dppz)(py)]+. 10 The radiative transitions occur from the two lowest-lying doublet 2E g and 2T 1g excited states to 4A 2g ground state (Oh symmetry) [34][35] giving well-resolved phosphorescence bands centred at about 730 nm and 698 nm, respectively (see Fig. 2).…”

Section: Absorption and Emission Spectramentioning

confidence: 99%

“…For instance it is often possible to select a complex with an excited state having an appropriate redox potential or one which shows exquisite sensitivity to its environment. [10][11][12][13][14][15][16][17][18] These properties are particularly valuable for potential therapeutic and diagnostic applications involving the interaction of such complexes with nucleic acids or proteins. [19][20] For example, directed photooxidative damage of nucleic acids opens the possibility of designing a new class of selective antitumour drugs.…”

Section: Introductionmentioning

confidence: 99%

Excited state behaviour of substituted dipyridophenazine Cr(iii) complexes in the presence of nucleic acids

Wojdyła

Smith

Vasudevan

et al. 2010

Photochem Photobiol Sci

Self Cite

View full text Add to dashboard Cite

The photophysics and photochemistry of [Cr(phen) 2 (dppz)] 3+ and its 11,12-substituted derivatives [Cr(phen) 2 (X 2 dppz)] 3+ {X = Me or F} have been studied in the presence of purine nucleotides or DNA using steady state and time-resolved absorption and luminescence spectroscopy. 5′-Adenosine monophosphate (5′-AMP) shows only a weak interaction with the excited states of each complex. By contrast they are efficiently quenched by 5′-guanosine monophosphate (5′-GMP), consistent with photo-induced electron transfer. Laser flash photolysis spectroscopy in the presence of 5′-GMP suggests that both forward and back electron-transfers are rapid. All complexes also display a strong affinity for DNA and evidence for both static and dynamic quenching mechanisms is provided.Graphical Abstract:

show abstract

“…All ligands showed μs lifetimes of the transient absorbing states, see 10,20,34 Lifetimes can vary considerably with solvent and temperature, due to the environmental sensitivity of dppz, 8 and also depend on the nature of the probed state. 15 For example, Kuimova et al measured a 10 μs lifetime for [Re(CO) 3 ( py)(dppz-(CO 2 Et) 2 )] + in MeCN, while Dyer et al measured 3.5 μs for [Re(CO) 3 ( py)(dppz)] + in MeCN; in both cases this state is assigned as π,π* in nature.…”

Section: Transient Absorption Spectroscopymentioning

confidence: 99%

Stretching the phenazine MO in dppz: the effect of phenyl and phenyl–ethynyl groups on the photophysics of Re(i) dppz complexes

et al. 2014

View full text Add to dashboard Cite

A series of dipyrido[3,2-a:2',3'-c]phenazine (dppz)-based ligands have been synthesised in which phenyl or phenyl-ethynyl linkers are terminated by (t)Bu or CN units. The corresponding [ReCl(CO)3(L)] complexes are also prepared. Electrochemistry shows the ligand which contains a phenyl-ethynyl linker and CN substituent is most easily reduced (by 15 mV relative to the other ligands). All complexes are reduced and oxidised at similar potentials. Electronic absorption spectra are consistent with stabilisation of the LUMO by the binding of the metal centre, as complex spectra are red-shifted relative to their ligand. In addition, those containing phenyl-ethynyl linkers show spectra red-shifted (by 650 cm(-1)) relative to their phenyl-linked analogues. Raman and resonance Raman spectroscopy combined with DFT and TD-DFT calculations are consistent with ligands showing π,π* transitions, and complexes showing metal-to-ligand charge-transfer (MLCT) transitions as the lowest energy absorption. Ligands emit from the π,π* excited state (λem ranging from 450 to 470 nm in CH2Cl2). The complexes show emission from both π,π* and MLCT states; the λem(MLCT) lies at 650-666 nm. Transient lifetimes in CH2Cl2 are decreased by the CN substituent, as this increases knr. Transient resonance Raman spectra (TR(2)) of ligands show spectral features associated with the LC state, and the strong similarities between these and complex spectra support an LC excited state at 355 nm for the complexes. Two-colour TR(3) spectra show only small differences to ground state spectra, the most obvious being a decrease in intensity of C[triple bond, length as m-dash]C bands. For [ReCl(CO)3()] and [ReCl(CO)3()] an increase in intensity of a 1575 cm(-1) band attributed to the dppz˙(-) species suggests that these complexes have significant MLCT state population between 20-60 ns after photoexcitation.

show abstract

Solvent dependent photophysics of fac-[Re(CO)3(11,12-X2dppz)(py)]+ (X = H, F or Me)

Cited by 30 publications

References 33 publications

Charge Photoinjection in Intercalated and Covalently Bound [Re(CO)₃(dppz)(py)]⁺–DNA Constructs Monitored by Time-Resolved Visible and Infrared Spectroscopy

Charge Photoinjection in Intercalated and Covalently Bound [Re(CO)₃(dppz)(py)]⁺–DNA Constructs Monitored by Time-Resolved Visible and Infrared Spectroscopy

Excited state behaviour of substituted dipyridophenazine Cr(iii) complexes in the presence of nucleic acids

Stretching the phenazine MO in dppz: the effect of phenyl and phenyl–ethynyl groups on the photophysics of Re(i) dppz complexes

Contact Info

Product

Resources

About

Solvent dependent photophysics of fac-[Re(CO)3(11,12-X2dppz)(py)]+ (X = H, F or Me)

Cited by 30 publications

References 33 publications

Charge Photoinjection in Intercalated and Covalently Bound [Re(CO)3(dppz)(py)]+–DNA Constructs Monitored by Time-Resolved Visible and Infrared Spectroscopy

Charge Photoinjection in Intercalated and Covalently Bound [Re(CO)3(dppz)(py)]+–DNA Constructs Monitored by Time-Resolved Visible and Infrared Spectroscopy

Excited state behaviour of substituted dipyridophenazine Cr(iii) complexes in the presence of nucleic acids

Stretching the phenazine MO in dppz: the effect of phenyl and phenyl–ethynyl groups on the photophysics of Re(i) dppz complexes

Contact Info

Product

Resources

About

Charge Photoinjection in Intercalated and Covalently Bound [Re(CO)₃(dppz)(py)]⁺–DNA Constructs Monitored by Time-Resolved Visible and Infrared Spectroscopy

Charge Photoinjection in Intercalated and Covalently Bound [Re(CO)₃(dppz)(py)]⁺–DNA Constructs Monitored by Time-Resolved Visible and Infrared Spectroscopy