1469-55-2Relevant academic research and scientific papers
Molecular spur gears comprising triptycene rotators and bibenzimidazole-based stators
Frantz, Derik K.,Linden, Anthony,Baldridge, Kim K.,Siegel, Jay S.
supporting information; experimental part, p. 1528 - 1535 (2012/03/10)
Dynamic gearing of molecular spur gears, the most common type of mechanical gear, is elucidated. Molecular design and conformational analysis show that derivatives of 4,4-bis(triptycen-9-ylethynyl)bibenzimidazole represent suitable constructs to investigate gearing behavior of collateral triptycene (Tp) groups. To test this design, DFT calculations (B97-D/Def2-TZVP) were employed and the results suggest that these molecules undergo geared rotation preferentially to gear slippage. Synthesis of derivatives was carried out, providing a series of molecular spur gears, including the first desymmetrized spur gear molecules, which were subsequently subjected to stereochemical analysis.
New Molecular Devices: In Search of a Molecular Ratchet
Ross Kelly,Sestelo, José Pérez,Tellitu, Imanol
, p. 3655 - 3665 (2007/10/03)
The triptycene-substituted [3]- and [4]helicenes 1 and 2 were examined as possible molecular versions of mechanical ratchets, where the triptycene serves as the ratchet wheel and the hehcenes as pawl and spring. The syntheses of 1 and 2b are described. 1H NMR was employed to examine rotation around the triptycene/helicene single bond; at 20 °C rotation is frozen for both 1 and 2b but the NMR of 1 revealed a plane of symmetry, indicating that 1 cannot function as a unidirectional ratchet In contrast, NMR revealed that, like a ratchet, triptycvl[4]helicene 2b lacks the symmetry of 1 and has a barrier to rotation of 24.5 kcal/mol, but spin polarization transfer NMR expenments indicated the triptycene in 2b nonetheless rotates equally in both directions. That outcome is rationalized from the standpoint of thermodynamics.
