Abstract

The photochemical cleavage of covalent bonds is an important strategy in protection group chemistry, as well as for the triggering of chemical events posterior to the application of the physicochemical stimulus. Photocages allow the arresting and traceless liberation of a chemical entity, which can be broadly applied as a functional control element in materials chemistry and the life sciences in general. Among the best studied and most versatile light-sensitive protecting groups known to date rank the o-nitrobenzyl derivatives, entities which are easily introduced to amines, thiols, and alcohols. Their photolability relies on a phototautomerisation-induced cleavage mechanism, a phenomenon largely dependent on the substitution pattern of the aromatic ring in the o-nitrophenyl-moiety. Although well described and studied in detail for the protection of amino groups of different nature, the photocaging of aliphatic diamines has not been described in detail to date. Because of their interesting properties as synthons in supramolecular and polymer chemistry alike, we wish to describe the efficient photocaging of diamines with o-nitrobenzyl derivatives, their photocleavage behavior over time, as well as their application in a photoinduced templated self-assembly reaction towards cyclic imines.