Highly selective recognition and fluorescence imaging of adenosine polyphosphates in aqueous solution

The design and synthesis of chemosensors for the recognition of a certain nucleoside polyphosphate among various structurally similar nucleoside polyphosphates remain a fundamental challenge. Herein, we report the new fluorescent chemosensor [Zn2L](ClO4)4 (1; L = (3,6,10,13,17,20,24,27-octaaza-1,15(2,6)-dipyridina-8,22(9,10)-dianthracenacyclooctacosaphane), which can selectively recognize adenosine polyphosphates (ATP and ADP) among various nucleoside polyphosphates, with a large fluorescence enhancement (Fmax/F0 = 70 and 80 for ATP and ADP, respectively) and strong binding affinity (K = 3.1 × 10(11) M(-1) for [Zn2HL(H-1ATP)2](-), 2.8 × 10(11) M(-1) for [Zn2L(H-1ATP)2](2-), and 1.5 × 10(13) M(-1) for [Zn2L(H-1ADP)2](2-)) in aqueous solution at physiological pH 7.40. The structure of [Zn2L](P2O7) (2) was investigated, which shows that μ2-pyrophosphate anions alternately link [Zn2L](4+) cations to generate a 1D coordination polymer. The results of (31)P NMR studies and DFT calculations reveal that the two Zn(II) ions in 1 can interact with ATP/ADP anions through coordination interactions between Zn(II) and the polyphosphate groups, and two anthracene moieties in 1 can interact with adenine groups from two ATP or ADP anions through stacking interactions to form a sandwichlike structure. These multiple recognition interactions between 1 and ATP/ADP enhance the affinity and selectivity of 1 toward ATP/ADP. Due to its highly selective and sensitive ability to detect adenosine polyphosphates, 1 was successfully applied to fluorescence imaging for ATP and ADP in living cells, demonstrating the potential utility of 1 as a fluorescent chemosensor for detecting ATP and ADP.