From UV to NIR light, photo-triggered 1,3 dipolar cycloadditions as a modern ligation method in solution and on surface

Abstract

angefertigt.Ich erkläre hiermit, dass ich die vorliegende Arbeit im Rahmen der Betreuung durch Prof. tracking. In addition, the trigger wavelength of the pyrene functionalized tetrazole was extended deep into the NIR range via the combination of the NITEC with upconversion nanoparticles (UCNPs). Assisted by the UCNPs, photoinduced ligation of both, small and macromolecules was obtained with irradiation at 974 nm. Full conversion and rapid formation of the desired pyrazoline cycloadducts were observed. In addition, a block copolymer featuring the biological relevant biotin moiety was prepared via NITEC at 974 nm, demonstrating the suitability of the approach for applications in the field of biology. Biotin was found to retain bioactivity after being exposed to the NITEC reaction conditions. The efficient penetration ability of the NIR irradiation applied was verified by 'through tissue' conjugation experiments. After the NITEC reaction was demonstrated to be a powerful ligation tool in solution, the concept was employed for the modification of surfaces in a λ-orthogonal approach. The selective ability of the pyrene tetrazole and an UV-active diaryl tetrazole to undergo independent NITEC reactions at 410 -420 nm, and 320 nm respectively, was demonstrated in solution. Importantly, the UV-active tetrazole remains unreacted if exposed to visible light, even for prolonged irradiation times. Subsequently, a surface grafted with pyrene functional tetrazole and UV-active tetrazole was prepared and utilized for formation of advanced patterned surfaces.