| Abstract: | The assembly sequence of the coordination cluster Zn5(H2Ln)6](NO3)4]⋅8 H2O⋅2 CH3OH ( Zn5 , H3Ln=(1,2‐bis(benzod]imidazol‐2‐yl)‐ethenol) involves in situ dehydration of 1,2‐bis(benzod]imidazol‐2‐yl)‐1,2‐ethanediol (H4L) through the formation of the Zn(H3L)2]+ monomer, dimerization to Zn2(H3L)2]+, dehydration of the ligand to Zn2(H2Ln)2]+, and the final formation of the pentanuclear cluster. The cluster has the following special characteristics: 1) high stability in both refluxing 37 % HCl and 27 % NH3, 2) low cytotoxicity, and 3) pH‐sensitive fluorescence in the visible‐to‐near‐infrared (Vis/NIR) region in the solid state and in solution. We have applied it as a fluorescent probe both in vivo and in vitro. Its H‐bonding ability is the key to its affinity and selectivity for imaging lysosomes in HeLa cells and tumors in male BALB/C mice. It provides a new type of sensitive and biocompatible fluorescent probe for detecting small tumors (13.5 mm3). |
