Light-driven motors, ultra-fast rotors and light emitting ligands engineered in 3D porous architectures

Rotors, motors and switches in the solid state find a favorable playground in porous materials, such as Metal Organic Frameworks (MOFs) and Porous Aromatic Frameworks (PAFs), thanks to their large free volume, which allows for fast dynamics. We have realized a fast molecular rotor in the solid state whose rotation speed approaches that of unhindered rotations in organic moieties even at very low temperatures (2 K). Continuos, unidirectional hyperfast rotation with an energy barrier of 6.2 cal/mol and a high frequency persistent for several turns are achieved (10 GHz below 2 K).[1] Responsive porous switchable framework materials endowed with light-responsive overcrowded olefins, took advantage of both the quantitative photoisomerization in the solid state and the porosity of the framework to reversibly modulate the gas adsorption in response to light. [2] Motors were inserted into metal-organic frameworks wherein two linkers with complementary absorption-emission properties were integrated into the same materials. Unidirectional motion was achieved by simple exposure to sun-light of the solid particles, which thus behave as autonomous nanodevices.[3] MOF nanocrystals comprising high-Z linking nodes interacting with the ionizing radiation, arranged in an orderly fashion at a nanometric distance from diphenylanthracene ligand emitters showed ultrafast sensitization of the ligand fluorescence, thus supporting the development of new engineered scintillators.[4,5] References 1. A. Comotti, P. Sozzani et al Nature Chem. 2020, 12, 845. 2. A. Comotti, B. L. Feringa et al Nature Chem. 2020, 12, 595. 3. A. Comotti, B. L. Feringa et al J. Am. Chem. Soc. 2020, 142, 9048. 4.P. E. Sozzani, A. Comotti, A. Monguzzi et al Adv. Mater. 2019, 31, 1903309. 5. A. Comotti, A. Monguzzi et al Nature Photonics 2021, doi 10.1038/s41566-021-00769-z.