Dinuclear Metal–Organic Material for Binary Optical Recording

Abstract

A diimine ligand tethered to anthracene in the 9‐position, 4′‐(9‐anthrylethyl)‐4‐methyl‐2,2′‐bipyridine (bpy‐An), was dimerized through cycloaddition photochemistry. The resultant head‐to‐tail photodimer (bpy‐PD) was used as a bridging ligand in the preparation of a new dinuclear RuII complex, [Ru(dmb)2(bpy‐PD)Ru(dmb)2]4+ (dmb = 4,4′dimethyl‐2,2′‐bipyridine). The corresponding mononuclear species containing anthracene ([Ru(dmb)2(bpy‐An)]2+ was also synthesized and serves as a model compound in this study. UV photolysis (λ < 300 nm) of the strongly luminescent RuII dinuclear complex results in cycloreversion, generating two anthracene‐containing mononuclear species, [Ru(dmb)2(bpy‐An)]2+, whose emission is largely quenched as a result of nonradiative triplet–triplet energy transfer. The photophysical and photochemical properties of the dinuclear system have been studied in CH3CN solutions and in solid polyvinyl alcohol (PVA) thin films. The “on”–“off” luminescence switching characteristics and concomitant non‐destructive readout properties suggested that these molecules could be useful in read‐only memory (ROM) applications. In the solid state, micrometer‐sized objects were imaged using visible light, taking advantage of the luminescence contrast generated from the UV photochemical reaction. These written images were stable for at least 6 months, indicating that long‐term binary data storage is indeed feasible in these ROM metal–organic materials.

Spectroscopy and Photophysics in Cyclometalated RuII–Bis(bipyridyl) Complexes

“…The widespread investigation of Ru II -polypyridyl complexes over the past 30 years largely has roots in their impressive photophysical and redox properties, which make them amenable for adaptation to a myriad of technologies including dye-sensitized solar cells (DSSCs), [1][2][3][4][5][6][7] solar fuels photochemistry, [8] light-emitting electrochemical cells, [9] photoluminescence sensors, [10] biophotonics, [11,12] photochromics, [13][14][15][16][17][18] water-oxidation catalysis, [19] low-power photon upconversion, [20][21][22][23] as well as fundamental studies in photoinduced electron and energy transfer. [24][25][26][27][28][29] Interestingly, the related class of Ru II molecules that incorporate one or more cyclometalating ligands into their structure were only sparingly investigated over the same time frame.…”

Fabrication of Reversibly Crosslinkable, 3‐Dimensionally Conformal Polymeric Microstructures

“…[19,20] The dimer can be reversed to the original monomers (photoscission) upon exposure to short-wave UV light (<300 nm). This versatile reaction has been demonstrated in diverse areas such as optical memory, [21][22][23] langmuir-blodgett monolayers, [24] biosensors, [25,26] and hydrogels. [27,28] Herein, we report the preparation of an anthracene functional poly(methyl acrylate) CCS polymer by the ''arm first'' approach, utilizing atom transfer radical polymerization (ATRP).…”

Stereo- and regioselective photocycloaddition of extended alkenes using γ-cyclodextrin

“…Photocycloaddition [2+2] is one of the most studied and practically useful chemical reactions. 1 Its utility in applied fields such as photopolymerization, 2, 3 material sciences, 4–6 photolithography, 7, 8 organic synthesis, 9, 10 and medicinal chemistry 11, 12 is immense. Product of [2+2] photocycloaddition (PCA), the tetrasubstituted cyclobutene core, is part of several natural compounds.…”