September 2024

We describe effective development of the highly diastereoselective synthesis of double helical tetraamine 2-H2-C2 and propose a mechanism for its formation. The resolution of 2-H2-C2 is facilitated by a high racemization barrier of 43 kcal mol–1 and it is implemented via either a chiral auxiliary or preparative supercritical fluid chromatography. This enables preparation of the first high-spin neutral diradical, with spin density delocalized within an enantiomeric double helical π-system. The presence of two effective 3-electron C–N bonds in the diradical leads to: (1) the triplet (S = 1) high-spin ground state with a singlet-triplet energy gap of 0.4 kcal mol–1 and (2) the long half-life of up to 6 days in 2-MeTHF at room temperature. The diradical possesses a racemization barrier of at least 26 kcal mol–1 in 2-MeTHF at 293 K and chiroptical properties, with an absorption anisotropy factor |g| ≈ 0.005 at 548 nm. These unique magnetic and optical properties of our diradical form the basis for the development of next-generation spintronic devices.1 Introduction2 Synthesis and Resolution of the C
2-Symmetric Double Helical Tetraamine 2-H2-C
2
3 Synthesis and Characterization of Neutral High-Spin Aminyl Diradical 22•
-C
2
4 Conclusion

The development of an effective catalytic system for the dehydrogenative coupling of hydrosilanes with alcohols remains an ongoing challenge, particularly for alcohol protection applications. In this study, we report the development and optimization of a highly efficient gold catalyst supported on fibrillated cellulose modified with citric acid. The catalyst exhibited remarkable catalytic activity under mild conditions with 0.01–0.05 mol% of Au loading, facilitating the formation of silyl ethers with excellent yield. Notably, our catalytic system overcomes the need for excess alcohol, typically required in such reactions, making it highly practical for alcohol protection applications. This work represents a significant advancement in the field of dehydrosilylation catalysis, offering a sustainable, efficient, and environmentally friendly approach for the synthesis of functional silanol-based materials and alcohol protection applications. The scope of substrates and the utility of the catalyst have been thoroughly studied.