Characterisation of the lowest singlet and triplet excited states of S-flurbiprofen

Jiménez, M. Consuelo; Miranda, Miguel A.; Tormos, Rosa; Vayá, Ignacio

doi:10.1039/b408530b

Cited by 42 publications

(80 citation statements)

References 27 publications

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“…Jimenez reported that irradiation of naproxen in the presence of β-CDs leads to more rapid disappearance of the drug naproxen. 24 It appears that photohaemolytic activity of diclofenac is reduced in the presence of β-CDs. This can be attributed to the different behavior of the complexed radical intermediates, rather than to greater drug photostability.…”

Section: Photodegradation Of Diclofenac With Cdsmentioning

confidence: 99%

Photochemical characteristics of diclofenac and its photodegradation of inclusion complexes with β-cyclodextrins

Qin¹,

Yang²,

Chen³

et al. 2012

Quím. Nova

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Recebido em 3/7/11; aceito em 29/9/11; publicado na web em 6/12/11 Diclofenac is one of most frequently detected compounds in the water cycle. In this work, the effect of initial concentration, liquid inclusion complexes with β-Cyclodextrins (β-CDs) on the photodegradation of diclofenac were studied. Six phototransformation products were detected by HPLC chromatograms. UV-absorption spectra of diclofenac and phototransformation products were determined. One of the phototransformation products was identified. The degradation followed pseudo-first-order kinetics. The experiment showed that irradiation of diclofenac in the presence of β-CDs increase photodegradation rate and determined the optimal molar ratio of diclofenac to β-CDs as 1:2. The reduced photohaemolytic activity of diclofenac in the presence of β-CDs may be attributed to the sequestering and stabilizing of the radical intermediates and /or photoproducts by complexation.

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Section: Photodegradation Of Diclofenac With Cdsmentioning

confidence: 99%

Photochemical characteristics of diclofenac and its photodegradation of inclusion complexes with β-cyclodextrins

Qin¹,

Yang²,

Chen³

et al. 2012

Quím. Nova

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“…From the photophysical point of view, FBP contains a biphenyl chromophore with well-known properties. 14 It exhibits a non-negligible intersystem crossing yield, so both the singlet and 55 triplet states can in principle serve to monitor its binding to a protein. Indeed, previous laser flash photolysis studies on FBP/HSA complexes showed that FBP binds to both sites I and II, but with higher affinity to site II.…”

Section: Introductionmentioning

confidence: 99%

Excited state interactions between flurbiprofen and tryptophan in drug–protein complexes and in model dyads. Fluorescence studies from the femtosecond to the nanosecond time domains

Vayá

Bonancía

Jiménez

et al. 2013

Phys. Chem. Chem. Phys.

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We report here on the interaction dynamics between flurbiprofen (FBP) and tryptophan (Trp) covalently linked in model dyads and in a complex of FBP with human serum albumin (HSA) probed by time-10 resolved fluorescence spectroscopy from the femto-to the nano-second timescales. In the dyads, a rapid (k > 10 10 s -1 ) dynamic quenching of the 1 FBP* fluorescence is followed by a slower (k > 10 9 s -1 ) quenching of the remaining 1 Trp* fluorescence. Both processes display a clear stereoselectivity; the rates are 2-3 times higher for the (R,S)-dyad. In addition, a red-shifted exciplex emission is observed, rising in 100-200 ps. A similar two-step dynamic fluorescence quenching is also observed in the FBP/HSA 15 complex, although the kinetics of the involved processes are slower. The characteristic reorientational times determined for the two enantiomeric forms of FBP in the protein show that the interaction is stronger for the (R)-form. This is, to our knowledge, the first observation of stereo-selective flurbiprofentryptophan interaction dynamics with femtosecond time resolution.

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“…2, 52.1, 114.9, 119.4, 127.0, 127.9, 129.0, 129.3, 130.8, 136.8, 141.8, 152.5, 174.7 1H, J = 8.0Hz), 6.28 (s,1H),6.50 (d,1H,J = 2.4 Hz),6.80 (m,2H),4H),10H),8.11 (bs,1H). 13 C-NMR (CDCl3) (, ppm) 18. 3, 27.5, 46.8, 52.6, 52.8, 109.5, 111.4, 115.1, 118.6, 119.7, 120.2, 122.2, 123.2, 127.5, 127.9, 129.0, 5 129.2, 130.9, 136.1, 137.5, 142.2, 153.3, 172.5, 173.9 N-[2-(S)-(2-Hydroxy-1,1'-biphenyl-4-yl) 4, 46.7, 52.4, 52.9, 109.9, 111.2, 115.1, 118.6, 119.7, 120.0, 15 122.2, 122.3, 127.2, 127.6, 127.7, 129.1, 130.7, 136.0, 137.1, 141.7, 152.9, 172.3, 173.3 …”

Section: Characterisation Of the New Compoundsmentioning

confidence: 99%

Stereodifferentiation in the intramolecular singlet excited state quenching of hydroxybiphenyl–tryptophan dyads

et al. 2013

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The photochemical processes occurring in diastereomeric dyads (S,S)-1 and (S,R)-1, prepared by conjugation of (S)-2-(2-hydroxy-1,1'-biphenyl-4-yl)propanoic acid ((S)-BPOH) with (S)-and (R)-Trp, have been investigated. In acetonitrile, the fluorescence spectra of (S,S)-1 and (S,R)-1 were coincident in 10 shape and position with that of (S)-BPOH, although they revealed a markedly stereoselective quenching.Since singlet energy transfer from BPOH to Trp is forbidden (5 kcal mol -1 uphill), the quenching was attributed to thermodynamically favoured (according to Rehm-Weller) electron transfer or exciplex formation. Upon addition of 20% water, the fluorescence quantum yield of (S)-BPOH decreased, while only minor changes were observed for the dyads. This can be explained by an enhancement of the excited 15 state acidity of (S)-BPOH, associated with bridging of the carboxy and hydroxy groups by water, in agreement with the presence of water molecules in the X-ray structure of (S)-BPOH. When the carboxy group was not available for coordination with water, as in the methyl ester (S)-BPOHMe or in the dyads, this effect was prevented; accordingly, the fluorescence quantum yields did not depend on the presence or absence of water. The fluorescence lifetimes in dry acetonitrile were 1.67, 0.95 and 0.46 ns for (S)-20 BPOH, (S,S)-1 and (S,R)-1, respectively, indicating that the observed quenching is indeed dynamic. In line with the steady-state and time-resolved observations, molecular modelling pointed to a more favourable geometric arrangement of the two interacting chromophores in (S,R)-1. Interestingly, this dyad exhibited a folded conformation in the solid state.

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Characterisation of the lowest singlet and triplet excited states of S-flurbiprofen

Cited by 42 publications

References 27 publications

Photochemical characteristics of diclofenac and its photodegradation of inclusion complexes with β-cyclodextrins

Photochemical characteristics of diclofenac and its photodegradation of inclusion complexes with β-cyclodextrins

Excited state interactions between flurbiprofen and tryptophan in drug–protein complexes and in model dyads. Fluorescence studies from the femtosecond to the nanosecond time domains

Stereodifferentiation in the intramolecular singlet excited state quenching of hydroxybiphenyl–tryptophan dyads

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