Fluorescent Sensing of IP₃ with a Trifurcate Zn(II)-Containing Chemosensing Ensemble System

Abstract

A trifurcate receptor containing Zn(II)-dipicolylamine ligands is developed for the fluorescent sensing of IP 3, myo-inositol 1,4,5-tris(phosphate), through an indicator displacement approach. The chemosensing ensemble containing the Zn(II) complex and eosin Y as indicator shows the maximum fluorescence restoration for IP 3 among various other anions including phosphate derivatives in water buffered at pH = 7.

Anion recognition and sensing with Zn(ii)–dipicolylamine complexes

“…A similar strategy to increasing binding affinity has been employed by Gunning and co-workers who have developed a systematic synthetic route to orthogonally functionalized bis[Zn(II)-DPA] receptors based on the m-xylylene scaffold 53, providing a library of asymmetrically functionalized bis[Zn(II)-DPA] complexes 70-77. 87 Anion binding studies by isothermal titration calorimetry in 50 mM HEPES buffer (pH 7.4) at 25 1C showed that of those receptors examined (53,(70)(71)(72)(73)(74), receptor 71 has the highest affinity for NaH 2 PO 4 (K ass = 1.5 Â 10 6 M À1 ), which represents B10-fold enhancement over the unsubstituted receptor 53. However, the introduction of hydrogen bonding groups did not increase binding affinity in all cases, with 73 and 74 having similar and slightly lower affinity, respectively, for NaH 2 PO 4 to that exhibited by the parent 53.…”

“…14). 74,75 In HEPES buffer solution (10 mM, pH 7.0), receptor 60 binds to eosin Y with a 1 : 2 stoichiometry as determined by fluorescence and UV-vis titrations. 74 The association constants were found to be K 1 = 1.2 Â 10 6 M À1 and K 2 = 8.2 Â 10 4 M À1 by UV-vis titrations.…”

“…74,75 In HEPES buffer solution (10 mM, pH 7.0), receptor 60 binds to eosin Y with a 1 : 2 stoichiometry as determined by fluorescence and UV-vis titrations. 74 The association constants were found to be K 1 = 1.2 Â 10 6 M À1 and K 2 = 8.2 Â 10 4 M À1 by UV-vis titrations. Upon the addition of IP 3 (2.0 mM) the fluorescence of the ensemble containing 2.0 mM of 60 and 3.0 mM of eosin Y was enhanced by B3-fold, with lower enhancement observed for other phosphate oxoanions in the order PPi 4 ATP > ADP.…”

Controlling dynamic stereoisomerism in transition-metal folded baskets

“…1A) have been scrutinized for understanding the activation of C-H bonds [25][26][27] and obtaining stimuli-responsive switches/ sensors. 19,28,29 In TPA coordination systems, the propeller-like chirality was controlled with an alkyl substituent: the alkyl group would, as a relay auxiliary, 30 promote the formation of predominantly one twisted diastereomer (Fig. 1A).…”

Design, synthesis and evaluation of a tripodal receptor for phosphatidylinositol phosphates

“…Anslyn 9 , 10 , Ahn 11 , Yoon 12 , 13 , Aoki 14 , 15 and Best 16 have previously reported receptors for inositol phosphates such as IP 3 based on scaffolds substituted with phosphate-recognition moieties such as guanidinium, alkyl ammonium or imidazolium groups as well as zinc(II) complexes. While these receptors have shown high affinity and, in some cases, good selectivity for specific IPs (mainly IP 3 ), their binding to PIPs (i.e.…”