Synthesis and Photochromic Properties of Molecules Containing [e]-Annelated Dihydropyrenes. Two and Three Way π-Switches Based on the Dimethyldihydropyrene−Metacyclophanediene Valence Isomerization

Abstract

The syntheses of several new simple negative, a simple positive, and multiple negative photochromes containing the dihydropyrene-cyclophanediene photochromic system are described. The photo-openings of the negative photochromes, the [e]-annelated benzo (7), naphtho (9), anthro (11), furano (19), and triphenyleno (15) derivatives of the parent 2,7-di-tert-butyl-trans-10b,10c-dimethyl-dihydropyrene (5), as well as its 4,5-dibromo derivative (13), are described to give the corresponding cyclophanedienes, as well as their photoclosures and thermal closures back to the dihydropyrenes. These are compared to the results obtained for the positive photochrome dibenzo[e,l]dihydropyrene (21) and to the bis(dihydropyreno)chrysene (44) and the (dihydropyrenobenzo)(benzo)metacyclophanediene (47) photochromes, which have more than one photochromic switch present and thus have more than a simple "on-off" state. Thermodynamic data are obtained for the thermal closing reactions. The anthrodihydropyrene (12) has the fastest thermal closing (tau(1/2) = 20 min), while the furanodihydropyrene (19') has the slowest (tau(1/2) = 63 h) at 46 degrees C. An electrochemical readout of the state of the switch is demonstrated for the benzodihydropyrene (7).

Reactivity of a pyridinium-substituted dimethyldihydropyrene switch under aerobic conditions: self-sensitized photo-oxygenation and thermal release of singlet oxygen

“…The DHP-CPD photochromic couple belongs to the family of diarylethenes. [31][32][33][34][35][36] The colored DHP ("closed" form) unit features a planar aromatic skeleton having 14 delocalized π electrons and two methyl groups pointing in opposite directions on either side of the plane. Under visible-light irradiation, the colorless CPD isomer ("open" state) is formed through the cleavage of the central carbon-carbon bond.…”

Charge-Transfer Interactions in Organic Functional Materials

“…Recently, bichromophoric and multichromophoric cyclophanes have been studied for organic solids [113,114,115], biosensors [116,117], eletrocyclic reactions [118,119,120,121], two-photon absorptions [122,123,124], mixed-valence systems [125,126], and nonlinear optical materials [16,17,18]. Particularly, Bazan et al have exploited the advantage of well-defined three-dimensional structures in cyclophanes that contains [2.2]paracyclophane core and found their potential applications in designing organic nonlinear optical materials [16,17].…”

All‐Photonic Molecular XOR and NOR Logic Gates Based on Photochemical Control of Fluorescence in a Fulgimide–Porphyrin–Dithienylethene Triad

“…Logic gates using chemical and/or optical inputs and optical outputs are by far the most common. [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] Typically, in these systems, addition of acid, base, or a metal ion leads to a large change in the emission or absorption properties of the molecule, although switching by light has also been realized.…”