A hybrid molecular peapod of sp- and sp-nanocarbons enabling ultrafast terahertz rotations.

The internal hollow space of carbon nanotubes provides a unique nanometre-sized space to capture various molecular entities. The inner space circumfused by sp-carbon networks can also encapsulate diamondoid molecules to afford sp/sp-hybrid nanocarbon peapods that have recently emerged as unique nanostructures. In this study, the sp/sp-hybrid peapods have been mimicked by adopting a cylindrical molecule and the smallest diamondoid, i.

Narrowing Segments of Helical Carbon Nanotubes with Curved Aromatic Panels.

Rigid molecular cylinders with a 1 nm diameter were synthesized by assembling arylene panels with Pt-mediated macrocylization. Chrysenylene panels that previously participated in tetrameric macrocyclization were contorted by the addition of two benzo groups on the sides to form dibenzochrysenylene, which allowed for a reduction in the numbers of participating panels to three. Consequently, narrowed cyclochrysenylene congeners were obtained.

Enhanced yet Inverted Effects of π-Extension in Self-Assembly of Curved π-Systems with Helicity.

A sextuple helix molecule possessing four cove regions of helicene and two axes of biaryls was synthesized. The entropy-driven self-assembly in solution was determined by concentration- and temperature-dependent NMR spectra, which also revealed unique dynamics of isomerization involving structural changes at the cove regions. Unexpectedly, the assembly retarded the isomerization in solution, and the sextuple helix structure was rigidified.

Chimeric RNA Oligonucleotides Incorporating Triazole-Linked Trinucleotides: Synthesis and Function as mRNA in Cell-Free Translation Reactions.

A method for the synthesis of chimeric oligonucleotides was developed to incorporate purine nucleobases and multiple triazole linkers in natural, phosphate-linked structures of RNA. A solution-phase synthesis method for triazole-linked RNA oligomers via copper-catalyzed azide-alkyne cycloaddition reaction was optimized and tolerated purine nucleobases and protecting groups for further transformations. Three RNA trinucleotides with 5'-protected hydroxy and 3'-phosphoramidite groups were prepared, and one congener with a representative sequence was subjected to automated, solid-phase phosphoramidite synthesis.

Chimeric RNA Oligonucleotides with Triazole and Phosphate Linkages: Synthesis and RNA Interference.

Chimeric RNA oligonucleotides with an artificial triazole linker were synthesized using solution-phase click chemistry and solid-phase automated synthesis. Scalable synthesis methods for jointing units for the chimeric structure have been developed, and after click-coupling of the jointing units with triazole linkers, a series of chimeric oligonucleotides was prepared by utilizing the well-established phosphoramidite method for the elongation. The series of chimeric 21-mer oligonucleotides that possessed the triazole linker at different strands and positions allowed for a screening study of the RNA interference to clarify the preference of the triazole modifications in small-interfering RNA molecules.