A theoretical study on magnesium ion-selective two-photon fluorescent probe based on benzo [h] chromene derivatives.

The geometrical structure, electronic structure, and one-photon absorption (OPA) properties of a series of magnesium ion (Mg)-selective fluorescent probes based on benzo [h] chromene derivatives have been theoretically studied by using density functional theory (DFT) method and Zerner's intermediate neglect of differential overlap (ZINDO) methods. Their two-photon absorption (TPA) properties are also calculated by using the method of ZINDO/sum-over-states. Results show that all studied probe molecules exhibit large TPA cross-section (δ) in response to Mg in 700- to 1,200-nm range. Furthermore, the δ can be greatly enhanced by introducing acceptor groups to the lateral side of benzo [h] chromene. And that probes with stronger acceptor group show larger δ and result in 70-fold enhancing when coordinate with Mg. Significantly, probe molecules with good cell permeability were also studied by replacing the hydrogen group with acetoxymethyl ester, but δ changed slightly. These results shed light into the design strategy of efficient TP fluorescent probes with large δ and good cell permeability for Mg sensing in living systems. [ABSTRACT FROM AUTHOR]