Intramolecular excimer study of rates of conformational transitions. Dependence on molecular structure and the viscosity of the medium

Goldenberg, Merrill; Emert, Jack; Morawetz, Herbert

doi:10.1021/ja00491a008

Cited by 108 publications

(65 citation statements)

References 6 publications

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“…According to Birks (25), at low temperatures (below Tmax), kiD is independent of temperature. The existence of an isoemissive point when temperature is varied indicates that kiD is independent of temperature (22,24,26).…”

Section: Od Idmentioning

confidence: 99%

“….X PI kfM kiM Py kfD kiD where Py represents pyrene in the ground state, Py* is pyrene in the excited state, and kfm, kjM, kfD, kiD, ka, and kd are rate constants for monomer fluorescence, monomer internal quenching, excimer fluorescence, excimer internal quenching, excimer formation, and excimer dissociation, respectively. The ratio of quantum yields of excimer fluorescence, D, to monomer fluorescence, OM, is related to these rate constants (24) by 'Abbreviations used in this paper: PC3P, 1,3-dipyrenylpropane; DPH, 1,6-diphenyl-1,3,5-hexatriene; BSA, bovine serum albumin; THF, tetrahydrofuran; DMPC, 1,2-dimyristoyl phosphatidylcholine; DPDL, 1,2-bis[w-(1-pyreno) decanoyl]-sn-glycero-3-phosphorylcholine; IM, corrected intensity of monomer emission; ID, corrected intensity of excimer emission.…”

Section: Introductionmentioning

confidence: 99%

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Use of fluorescent probes that form intramolecular excimers to monitor structural changes in model and biological membranes

Melnick¹,

Haspel²,

Goldenberg³

et al. 1981

Biophysical Journal

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1,3-dipyrenylpropane (PC3P) and bis(4-biphenylmethyl)ether, two molecules that form intramolecular excimers, were embedded in phospholipid vesicles and biological membranes to monitor dynamic properties of membrane lipids. Excimer formation was evaluated from determinations of excimer to monomer emission intensity ratios (ID/IM). ID/IM values of PC3P and bis(4-biphenylmethyl)ether were reduced when cholesterol was added to egg lecithin vesicles. PC3P was sensitive to the temperature-induced crystalline to liquid-crystalline phase transition in dimyristoyl phosphatidylcholine vesicles. For studies of cellular membranes, membranes, PC3P was used exclusively, because of the fluorescence of tryptophan residues of membrane proteins interferes with the responses bis(4-biphenylmethyl)ether. Microviscosities of membrane interiors were calculated from standard curves of IM/ID plotted against solvent viscosity. Microviscosity values of egg lecithin vesicles and biological membranes, especially those obtained with PC3P, were more than an order of magnitude lower than values obtained by other techniques. We concluded that the intramolecular process leading to the formation of the excimer is influenced differently in isotropic solvents than in anisotropic environments, such as lipid bilayers. Although distinguishable ID/IM ratios can be obtained for different biological membranes (mitochondrial, microsomal, and plasma membranes were studied), this parameter may be phenomenological and not simply related to membrane microviscosity. As such, fluorescent probes that form intramolecular excimers are of value in making qualitative comparisons of different membranes and in studying the relative effects of physical changes and chemical agents on membrane structure. These probes may also be valuable for studying structural anisotropy of biological membranes.

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Section: Od Idmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Use of fluorescent probes that form intramolecular excimers to monitor structural changes in model and biological membranes

Melnick¹,

Haspel²,

Goldenberg³

et al. 1981

Biophysical Journal

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“…47,48,53,54 It is clear from these investigations that the excimer emission depends most importantly on the solvent property/composition. 47,48,[53][54][55]58,59 The chain length, chain structure, actual fluorophore chemistry, exact labeling site on the fluorophore and the chain, tether length and its chemistry, temperature, and pressure also play a part. Among the dipyrenylalkanes, 1,3-bis-(1-pyrenyl)propane, [1Py (3)1Py], is perhaps the most investigated as the intramolecular excimer formation dynamics of 1Py (3)1Py is shown to be highly sensitive to the temperature and the solubilizing milieu.…”

Section: ■ Introductionmentioning

confidence: 99%

Intramolecular Excimer Formation Dynamics of 1,3-Bis-(1-pyrenyl)propane within 1-Butyl-3-methylimidazolium Hexafluorophosphate and Its Polyethylene Glycol Mixtures

2015

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Mixtures of ionic liquid with polyethylene glycol (PEG) have shown interesting features as solubilizing media. Intramolecular excimer formation dynamics of 1,3-bis-(1-pyrenyl)propane [1Py(3)1Py] is investigated within mixtures of a common and popular ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) with PEGs of average molecular weight (MW) 200 (PEG200), average MW 400 (PEG400), number-average MW Mn 570-630 (PEG600), and number-average MW Mn 950-1050 (PEG1000) over the complete composition range at a 10° interval in the temperature range 10-90 °C. Irrespective of the composition of the medium and the temperature, excited-state intensity decay of the excimer fluorescence best fits to a three-exponential decay function, suggesting the presence of one excited-state monomer and two kinetically distinguishable excimers where both excimers are populated simultaneously by the excited monomer with no interconversion between the two excimers. In neat PEGs for temperatures ≤ 50 °C, intensity decay data of monomer fluorescence best fits to a single-exponential decay function, which implies the dissociation of both excimers back to the monomer to be insignificant. As the temperature is increased, the fits become closer to a double-exponential decay function, implying dissociation of one of the excimers to become significant. In neat [bmim][PF6], while a double-exponential decay function is required to fit the monomer excited-state intensity decay data at lower temperatures, three exponentials are required to satisfactorily fit the data at higher temperatures, suggesting both excimers significantly dissociate back to the monomer at higher temperatures within the ionic liquid. Within long-chain PEG-containing ([bmim][PF6] + PEG) mixtures, PEG as opposed to [bmim][PF6] controls the excimer formation dynamics by supposedly wrapping around the excimer, thus hindering dissociation back to the monomer. The overall rate constant of the excimer formation within ([bmim][PF6] + PEG) mixtures is found to scale better with the microviscosity rather than the bulk viscosity of the mixtures.

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“…The exponential factors γ i are related to the decay times in the same way as for a bicompartmental system [43][44][45]47 and are explicitly given for the model depicted in Scheme 2 by γ 1 ) -k 03 and γ 2,3 given by with In eqs 10, a 21 and a 31 equal k 21 [M] and k 31 [M], respectively, for intermolecular processes and k 21 and k 31 , respectively, for intramolecular processes.…”

Section: Tricompartmental Systems Without Added Quenchermentioning

confidence: 99%

“…In other words, for each value of k 32 , one can compute values of k 21 and k 31 . Hence, the model depicted in Scheme 3 is identifiable if k 01 , k 02 , k 12 , and k 32 are assumed to be known.…”

Section: Tricompartmental Systems Without Added Quenchermentioning

confidence: 99%

Intramolecular Excited-State Processes of a Halato-Telechelic Polymer, Evaluated by Global Compartmental Analysis of the Fluorescence Decay Surface with the Use of Model Compounds

et al. 1997

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The excited-state processes of the halato-telechelic polymer bis [(N,N-dimethyl-N-[3-(1-pyrenyl)propyl]ammonio)trifluoromethanesulfonate]-end-capped poly(tetrahydrofuran) at low concentrations are investigated by time-resolved fluorescence. The photophysical processes can be described by an intramolecular three-state excited-state model. Such a system is not identifiable in the absence of a priori information. It is possible to perform a global compartmental analysis of the fluorescence decay surface using the scanning technique, based on model compound data previously obtained [Hermans et al., J. Phys. Chem. 1994, 98, 13583 and Hermans et al. Macromolecules 1995, 28, 3380]. The value boundaries on the rate constant for ring closure of the chain ends show that this process is close to diffusion-controlled.

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Intramolecular excimer study of rates of conformational transitions. Dependence on molecular structure and the viscosity of the medium

Cited by 108 publications

References 6 publications

Use of fluorescent probes that form intramolecular excimers to monitor structural changes in model and biological membranes

Use of fluorescent probes that form intramolecular excimers to monitor structural changes in model and biological membranes

Intramolecular Excimer Formation Dynamics of 1,3-Bis-(1-pyrenyl)propane within 1-Butyl-3-methylimidazolium Hexafluorophosphate and Its Polyethylene Glycol Mixtures

Intramolecular Excited-State Processes of a Halato-Telechelic Polymer, Evaluated by Global Compartmental Analysis of the Fluorescence Decay Surface with the Use of Model Compounds

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