Designing artificial macromolecules with absolute sequence order represents a considerable challenge. Here we report an advanced light-induced avenue to monodisperse sequence-defined functional linear macromolecules up to decamers via a unique photochemical approach. The versatility of the synthetic strategy—combining sequential and modular concepts—enables the synthesis of perfect macromolecules varying in chemical constitution and topology. Specific functions are placed at arbitrary positions along the chain via the successive addition of monomer units and blocks, leading to a library of functional homopolymers, alternating copolymers and block copolymers. The in-depth characterization of each sequence-defined chain confirms the precision nature of the macromolecules. Decoding of the functional information contained in the molecular structure is achieved via tandem mass spectrometry without recourse to their synthetic history, showing that the sequence information can be read. We submit that the presented photochemical strategy is a viable and advanced concept for coding individual monomer units along a macromolecular chain.

Without previous modification, single-walled carbon nanotubes (SWCNTs) react as dienophiles in a single-step Diels−Alder [4 + 2] cycloaddition with diene terminal polymer strands. Cyclopentadienyl-capped poly(methyl methacrylate) (M n = 2900 g mol−1, PDI = 1.2) was grafted onto SWCNTs under mild conditions at ambient temperature as well as at 80 °C in the absence of any catalyst. Thermogravimetric analysis, elemental analysis, and X-ray photoelectron spectroscopy confirm the success of the reaction and allow to estimate the grafting density of the polymer chains on the SWCNTs via the above three independent methods (average grafting density of 0.064 mmol g−1 (0.029 chains nm−2) for samples reacted at ambient temperature and 0.086 mmol g−1 (0.039 chains nm−2) for samples reacted at 80 °C). In addition, high-resolution transmission electron microscopy images confirmed the presence of an amorphous polymer layer (∼3 nm) around the SWCNTs after functionalization.

We report the first photochemical protocol for the generation of sequence defined macromolecules employing two hetero bifunctional photoreactive synthons, exploiting the orthogonal nature of photochemical - via the use of caged dienes - and thermally driven ligation protocols. We demonstrate that the iterative alternating synthon addition to an initial bifunctional core under irradiation at ambient temperature enables the generation of a macromolecule with up to 10 units (M = 3231.58 g mol(-1), Đ = 1.00). The resulting macromolecules are monodisperse and feature absolute chain end fidelity. The unit-by-unit construction of the macromolecule is evidenced by Nuclear Magnetic Resonance Spectroscopy, Electrospray Ionization Mass Spectrometry and Size Exclusion Chromatography. The fundamental principle demonstrated herein paves the way for employing photochemical strategies for the design of sequence defined polymers.