The donor–acceptor biphenyl platform: A versatile chromophore for the engineering of highly efficient two-photon sensitive photoremovable protecting groups
in the o-nitrobenzyl, phenacyl, and 2-(o-nitrophenyl)propylseries with a donor–acceptorbiphenyl backbone, known to display excellent two-photon absorption cross-sections, were investigated in order to develop efficienttwo-photon sensitive photoremovable protecting groups. The 2-(o-nitrophenyl)propylseries was a more versatile platform to increase the two-photon sensitivity of photoremovable protecting