The donor–acceptor biphenyl platform: A versatile chromophore for the engineering of highly efficient two-photon sensitive photoremovable protecting groups

Abstract

Different photoremovable protecting groups in the o-nitrobenzyl, phenacyl, and 2-(o-nitrophenyl)propyl series with a donor-acceptor biphenyl backbone, known to display excellent two-photon absorption cross-sections, were investigated in order to develop efficient two-photon sensitive photoremovable protecting groups. The 2-(o-nitrophenyl)propyl series was a more versatile platform to increase the two-photon sensitivity of photoremovable protecting groups, leading to the p-alkoxy and p-bisalkylamino-4-nitro-[1,1'-biphenyl]-3-yl)propyl derivatives: PENB and EANBP respectively. Those two photoremovable protecting groups are to date the best caging groups for two-photon excitation at 800 and 740 nm respectively, offering attracting perspectives in chemical biology.

Development of Anionically Decorated Caged Neurotransmitters: In Vitro Comparison of 7‐Nitroindolinyl‐ and 2‐(p‐Phenyl‐o‐nitrophenyl)propyl‐Based Photochemical Probes

“…HPLC analysis showed no hydrolysis by the end of the second day of experiments. These data are consistent with previous reports of similar caged compounds [24, 36] . Finally, at 37°C we found that 2 showed 2.7% hydrolysis after 4 h and 15% after 24 hours (Supplemental Figure 1).…”

“…Taken together these data suggest that about 30% of the uncaging leads to a product that “hijacks” glutamate release. Goeldner and co-workers have reported similar results with some of their NPP-caged Glu compounds [24, 36] .…”

“…Since cuvette 2P photolysis of a PNPP-caged Glu has been reported to be at least 50× better than MNI-Glu [24] , or perhaps even 500× better for different acids in another related report [47] , thus we would expect such large differences to be detected by the biology very easily. For example, the 5-fold difference in photochemical properties between CDNI-Glu and MNI-Glu is readily apparent in the biology [31] .…”

Photoremovable Protecting Groups in Chemistry and Biology: Reaction Mechanisms and Efficacy

“…237 This has also been recently demonstrated by Goeldner and co-workers, who studied the photochemical properties of biphenyl-containing photoremovable protecting groups possessing the o -nitrobenzyl, phenacyl, and 2-( o -nitrophenyl)propyl functionalities. 238 …”

Optical control and study of biological processes at the single-cell level in a live organism

“…This large number of engineering constraints has led to the introduction of new types of photolabile protecting groups. Present challenges in the field of caging groups concern: improving the uncaging action cross sections with one- and two-photon absorption[129, 130];driving the uncaging reaction with absorption in the visible range[129, 131–135]quantifying the amount of uncaging (e.g. by means of fluorescence reporting)[136–141];…”