AUTOFLUORESCENCE BLEACHING W/ CELL DAMAGE: MICROSCOPY OF NAD(P)H IN RBL CELLS

（1998年5月11日提交《科学》杂志出版） 用于设计具有大双光子吸收的分子 横截面，（，已开发。 战略基于 对称电荷转移的概念，从一个 共轭系统的中间，或反之亦然，在激发时， 与（.我们发现新合成的 具有给体-（-给体， 供体-受体-供体和受体-供体-受体结构基序 显示出异常大的值（，高达150倍 反式芪 量子化学计算对这些新的 分子表明， 在激励时发生，并提供（与 实验 大（和高荧光量子点的组合 这里开发的分子所表现出的三重态产率提供了 在双光子荧光中获得前所未有的亮度的潜力 成像或增强双光子敏化中的光敏性， 分别。

(submitted for publication to Science, May 11, 1998) A strategy for the design of molecules with large two-photon absorption cross-sections, (, has been developed. The strategy is based on the concept that symmetrical charge transfer, from the ends of a conjugated system to the middle, or vice versa, upon excitation is correlated to enhanced values of (. We show that newly synthesized bis-styrylbenzene derivatives with donor-(-donor, donor-acceptor-donor, and acceptor-donor-acceptor structural motifs exhibit exceptionally large values of (, up to 150 times that of trans-stilbene. Quantum chemical calculations performed on these new molecules indicate that substantial symmetric charge redistribution occurs upon excitation, and provide ( values in good agreement with experiment. The combination of large ( and high fluorescence quantum yield of triplet yield exhibited by molecules developed here offers potential for unprecedented brightness in two-photon fluorescent imaging or enhanced photosensitivity in two-photon sensitization, respe ctively.