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Fluorescence spectroscopy provides an excellent technique for investigating heterogeneous systems, due to its high sensitivity and the large effect of the local environment on molecular emission. In addition, the use of polarity-sensitive fluorescent probes as guests in supramolecular host-guest inclusion complexes can be exploited in fluorescent sensors. This paper identifies, tabulates, and quantifies a series of useful polarity-sensitive fluorescent probes, with a wide range of polarity-dependent fluorescence responses. The degree of polarity sensitivity is quantified using the polarity sensitivity factor (PSF), developed in our laboratory. In most cases, such polarity-sensitive probes show increased emission as the local polarity is decreased (PSF > 1); 10 such probes are described. However, less commonly, 'reverse polarity dependence' can occur in which probe emission decreases with decreasing polarity (PSF < 1); four such probes are described. The mechanism for the observed polarity-induced fluorescence changes will also be discussed in selected representative cases. The purpose of this paper is to present details on a broad arsenal of polarity-sensitive fluorescence probes with varying properties, with potentially useful applications in the study of heterogeneous systems, including inclusion phenomena, and in practical applications such as fluorescent sensors, which will be useful to researchers studying supramolecular and other heterogeneous systems using fluorescence spectroscopy. Key words: fluorescence, fluorescent probes, polarity sensitivity, solvent effects, sensors. La spectroscopie de fluorescence constitue une excellente technique pour l'etude des systemes heterogenes grâce a sa sensibilite elevee et a l'ampleur de l'effet d'environnement local sur l'emission moleculaire. De plus, l'utilisation de sondes fluorescentes sensibles a la polarite comme invite dans des complexes d'inclusion de type hôte-invite supramoleculaires peut etre exploitee dans des capteurs fluorescents. Dans le present article, nous decrivons, compilons et quantifions une serie de sondes fluorescentes sensibles a la polarite dont la grande etendue des reponses fluorescentes en fonction de la polarite offre une possibilite d'application pratique. Nous avons quantifie le degre de sensibilite a la polarite au moyen du facteur de sensibilite a la polarite (FSP), une mesure developpee dans notre laboratoire. Dans la plupart des cas, de telles sondes sensibles a la polarite presentent un accroissement de l'emission a mesure que la polarite locale augmente (FSP > 1); dix de ces sondes sont decrites. Or, il arrive, moins souvent toutefois, qu'une << dependance inverse a la polarite >> se produise, où l'emission de la sonde decroit a mesure que la polarite diminue (FSP < 1); quatre de ces sondes sont decrites. Nous commentons egalement, dans certains cas representatifs, le mecanisme a l'origine des variations de fluorescence induites par la polarite que nous observons. Cet article vise a presenter des informations detaillees sur une vaste panoplie de sondes sensibles a la fluorescence aux proprietes variables et qui pourraient se reveler utiles dans l'etude de systemes heterogenes, dont l'etude des phenomenes d'inclusion, et dans des applications pratiques comme les capteurs fluorescents. Ces informations pourraient etre utiles aux chercheurs qui etudient les systemes supramoleculaires et d'autres systemes heterogenes a l'aide de la spectroscopie de fluorescence. [Traduit par la Redaction] Mots-cles : fluorescence, sondes fluorescentes, sensibilite a la polarite, effets de solvant, capteurs., Introduction Fluorescence spectroscopy (1) has been extensively and effectively applied to the study of heterogeneous environments (2,3) such as proteins, (4) membranes (5) and other biological structures, (6) supra-molecular inclusion [...]

The host properties of a bistren cage compound, previously reported to be an efficient anion sensor, are shown to include encapsulation of small aromatic guest molecules. It is also shown that the intrinsic fluorescence of this cage compound, arising from the anthracenyl moiety in its structure, is sensitive to the encapsulation of aromatic guests in aqueous solution and can be used to measure the binding constants for any such guest. This makes this bistren cage a rare example of a fluorescent host for aromatic guests, and suggests potential applications of this compound as a versatile fluorescent sensor for a variety of guests of interest. The binding of a number of benzene derivatives was studied; these were all found to form 1:2 host-guest inclusion complexes with a wide range in total binding constants ([K.sub.1][K.sub.2]), from 6.4 x [10.sup.3] to 3.5 x [10.sup.7] [(mol/L).sup.-2], indicating a significant degree of selectivity for different benzene derivatives. The binding strength was found to depend on both the guest polarity and aqueous solubility. Key words: bistren cage, host-guest inclusion, fluorescent host, binding constants. Pour un compose bistrene en forme de cage qui, selon des etudes anterieures, serait un senseur anionique efficace, on demontre que ses proprietes hotes incluent l'encapsulation de petites molecules aromatiques invitees. On demontre aussi que la fluorescence intrinseque de ce compose en cage, qui tire son origine dans la portion anthracenyle de sa structure, est sensible a l'encapsulation de molecules aromatiques hotes dans la solution aqueuse et qu'elle peut etre utilisee pour mesurer les constantes de fixation de telles molecules invitees. Cette propriete fait que bistrene en forme de cage est un rare exemple d'un hote pour invites aromatiques et suggere des applications potentielles de ce compose comme senseur fluorescent versatile pour une variete de molecules invitees presentant des interets divers. On a etudie la fixation d'un certain nombre de derives aromatiques qui forment tous des complexes d'inclusion hote:invite 1:2 pour lesquels les constantes de fixation totale ([K.sub.1][K.sub.2]) s'etalent de 6,4 x [10.sup.3] a 3,5 x [10.sup.7] [(mol/L).sup.-2], ce qui suggere un degre significatif de selectivite pour les differents derives du benzene. On a note que la force de la fixation depend a la fois de la polarite de la molecule invitee et de la solubilite dans l'eau. Mots-cles : cage bistrene, inclusion hote-invite, hote fluorescent, constantes de fixation. [Traduit par la Redaction], Introduction Supramolecular host-guest inclusion complexes, in which a small guest molecule becomes encapsulated within the internal cavity of a larger cage-like host molecule, have shown tremendous utility for molecular recognition, [...]