Influence of Donor on the Sensing Performance of a Series of Through‐Bond Energy Transfer‐Based Two‐photon Fluorescent Cu²⁺ Probes

Abstract

Optical properties of a series of molecular two-photon fluorescent Cu(2+) probes containing the same acceptor (rhodamine group) are analyzed using time-dependent density functional theory in combination with analytical response theory. Special emphasis is placed on evolution of the probes' optical properties in the presence of Cu(2+) . In this study, the compound with naphthalene as the donor is shown to be excellent ratiometric fluorescent chemosensor, whereas the compound with quinoline derivative as the donor shows off/on-typed colorimetric fluorescent response. For the compound with naphthalimide derivative as the donor, changing the connection between the donor and acceptor can efficiently prevent the fluorescent quenching of the probe both in the absence and presence of Cu(2+) . The donor moiety and the connection between donor and acceptor are thus found to play dominant roles on sensing performance of these probes. Moreover, distributions of molecular orbitals involved in the excitation and emission of the probes are analyzed to explore responsive mechanism of the probes. The through-bond energy transfer process is theoretically demonstrated. Our results are used to elucidate the available experimental measurements. This work is helpful to understand the relationships of structure with optical properties for the studied probes.

A General Strategy for Through‐Bond Energy Transfer Fluorescence Probes Combining Intramolecular Charge Transfer: A Silyl Ether System for Endogenous Peroxynitrite Sensing

“…[1] Thus, there is no requirement for substantial spectral overlap between the donor emission and acceptora bsorbance, [2] leading to al arge pseudo-Stokes shifts (PSS) and emission shift, which is favorable to avoid self-quenching andf luorescence detectione rrors becauseo fe xcitation back-scattering effects. Althoughn umerousr atiometric fluorescence probes have been implemented with TBET mechanism, thesep robes are predominantly based on spirolactam ring-opening to sensing ions or molecules (Figure 1a), such as Hg 2 + ions, [4][5][6][7][8][9][10][11][12][13] Cu 2 + , [14][15][16] Pd 2 + , [17] Sn 2 + , [18] Ce 4 + , [19] À OCl, [20][21][22][23] picric acid [24] and so on. Althoughn umerousr atiometric fluorescence probes have been implemented with TBET mechanism, thesep robes are predominantly based on spirolactam ring-opening to sensing ions or molecules (Figure 1a), such as Hg 2 + ions, [4][5][6][7][8][9][10][11][12][13] Cu 2 + , [14][15][16] Pd 2 + , [17] Sn 2 + , [18] Ce 4 + , [19] À OCl, [20][21]…”

“…Thus, there is no requirement for substantial spectral overlap between the donor emission and acceptor absorbance, leading to a large pseudo‐Stokes shifts (PSS) and emission shift, which is favorable to avoid self‐quenching and fluorescence detection errors because of excitation back‐scattering effects . Therefore, TBET has been widely reported as a strategy for creating ratiometric fluorescence probes with large PSS and emission shifts . Although numerous ratiometric fluorescence probes have been implemented with TBET mechanism, these probes are predominantly based on spirolactam ring‐opening to sensing ions or molecules (Figure a), such as Hg 2+ ions, Cu 2+ , Pd 2+ , Sn 2+ , Ce 4+ , − OCl, picric acid and so on.…”

“…Therefore, TBET has been widely reported as a strategy for creating ratiometric fluorescence probes with large PSS and emission shifts . Although numerous ratiometric fluorescence probes have been implemented with TBET mechanism, these probes are predominantly based on spirolactam ring‐opening to sensing ions or molecules (Figure a), such as Hg 2+ ions, Cu 2+ , Pd 2+ , Sn 2+ , Ce 4+ , − OCl, picric acid and so on. To our knowledge, only two TBET probes were recently reported based on non‐spirolactam for Fe 3+ and Al 3+ .…”

Sensing Performance and Efficiency of Two Energy Transfer-Based Two-Photon Fluorescent Probes for pH

“…However, most of the reported pH probes are based on one-photon excitation, in which the light penetration and imaging resolution are limited [10,11,12,13]. In this context, two-photon fluorescence microscopy, using two photons with lower energy as the excitation source, has attracted much attention for its evident advantages, such as localized excitation, increased penetration depth, and low tissue autofluorescence and self-absorption [14,15,16].…”