New insights in the photochromic spiro-dihydroindolizine/betaine-system.

Photoinduced ring-opening of a photochromic dihydroindolizine derivative monitored with femtosecond visible and infrared spectroscopy.

We present results of a femtosecond spectroscopy study of the ring-opening dynamics of the photochromic compound trimethyl-1'H-spiro[fluorene-9,1'-pyrrolo[1,2-b]pyridazines]-2',3',6'-tricarboxylate (also known as dihydroindolizine and abbreviated as DHI) in solvents of different polarities. We follow the ring-opening dynamics of photoexcited DHI by probing the transient response in the visible ...

A light-induced photochromic nanoswitch capable of non-destructive readout via fluorescence emission: cluster vs. single-molecule excitation of dihydroindolizines.

We have synthesized a prototype of a photochromic styrylquinolyl-dihydroindolizine (DHI), which forms a highly coloured and fluorescent betaine upon irradiation with lambda<400 nm. Embedding this photochromic DHI in a thin polymethyl methacrylate (PMMA) film permits the non-destructive readout via fluorescence at low temperature (77 K). Thus, either a non-destructive photoswitch or an informati...

Molecular AND logic gate based on electric dichroism of a photochromic dihydroindolizine.

Molecular AND and INHIBIT gates based on control of porphyrin fluorescence by photochromes.

A molecular triad consisting of a porphyrin (P) covalently linked to two photochromes-one from the dihydroindolizine family (DHI) and one from the dihydropyrene family (DHP)-has been synthesized and found to act as either a molecular AND logic gate or an INHIBIT gate, depending on the inputs and initial state of the photochromes. The basis of these functions is quenching of porphyrin fluorescen...

Allosteric Inhibitory Molecular Recognition of a Photochromic Dye by a Digestive Enzyme: Dihydroindolizine makes α-chymotrypsin Photo-responsive

The structural-functional regulation of enzymes by the administration of an external stimulus such as light could create photo-switches that exhibit unique biotechnological applications. However, molecular recognition of small ligands is a central phenomenon involved in all biological processes. We demonstrate herein that the molecular recognition of a photochromic ligand, dihydroindolizine (DH...