Exploiting chemoselectivity for discrete oligomer synthesis through sequential IrAAC and CuAAC reactions

Abstract

In this study, we introduce the pioneering use of two distinct metal-catalyzed azide–alkyne cycloaddition reactions, CuAAC and IrAAC, for the synthesis of discrete oligomers without requiring protection–deprotection manipulations. The key to this methodology lies in the exceptional chemoselectivity of these reactions towards different alkyne substrates, which ensures their orthogonality. Additionally, the differential reactivity of azido groups in the IrAAC process addresses the common challenge of using excess difunctional monomers within a symmetrical architecture. Remarkably, the discrete oligomer demonstrates facile interpretation in MS/MS analysis due to its two effective fragmentation patterns. This feature not only highlights the potential of this novel synthetic approach for the development of high-density digital polymers but also suggests the broader applicability of triazole-enriched architectures. Further enhancements through side chain modifications with various luminophores and subsequent photophysical studies underscore the potential of this strategy for practical applications.