Assembly, Two-Photon Absorption, and Bioimaging of Living Cells of A Cuprous Cluster Xuchun Wang Xiaohe Tian Qiong Zhang Pingping Sun Jieying Wu Hongping Zhou Baokang Jin Jiaxiang Yang Shengyi Zhang Chuankui Wang Xutang Tao Minhua Jiang Yupeng Tian 10.1021/cm2029855.s001 https://acs.figshare.com/articles/journal_contribution/Assembly_Two_Photon_Absorption_and_Bioimaging_of_Living_Cells_of_A_Cuprous_Cluster/2541082 A novel cuprous­(I) cluster Cu<sub>4</sub>I<sub>4</sub>L<sub>4</sub> (L = (<i>E</i>)-(4-diethylanilino-styryl)­pyridine) bearing strong two-photon absorption (TPA) was obtained using a facile assembly method, and the crystal structure has been determined. Quantum chemical calculations using time-dependent density functional theory (TD-DFT) reveals that the combination of the organic ligands with the three-dimensional Cu<sub>4</sub>I<sub>4</sub> core extends the electronic delocalization in the cluster, leading to strong two-photon absorption action. The TPA cross sections (Φσ<sub>2</sub>) of Cu<sub>4</sub>I<sub>4</sub>L<sub>4</sub> were enhanced with increasing polarity of solvents, which is quite different from the solvent effects on TPA in the literature. Compared to its free ligand, the cluster Cu<sub>4</sub>I<sub>4</sub>L<sub>4</sub> exhibits larger peak TPA cross sections in the near-infrared region, longer fluorescence lifetimes, higher quantum yield and photostability, lower cytotoxicity, and brighter two-photon fluorescent (TPF) bioimaging. These integrated advantages make it desirable to be applied as a two-photon fluorescent probe for labeling the nucleic acids in live cells. 2012-03-13 00:00:00 crystal structure Cu 4I Cu 4I core absorption section quantum chemical calculations fluorescence lifetimes assembly method peak TPA Living Cells ligand cluster Cu 4I exhibits TPF