Photoisomerization of bis(9-anthryl)methane and other linked anthracenes. The role of excimers and biradicals in photodimerization

Bergmark, William R.; Jones, Guilford; Reinhardt, T. E.; Halpern, Arthur M.

doi:10.1021/ja00489a018

Cited by 76 publications

(19 citation statements)

References 8 publications

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“…Photocyclomers of 1 and 2 ,55 3 56 and 4 57 have been identified. These isomers possess two interannular σ bonds between C(9)C(9′) and C(10)C(10′), respectively, incorporating the oligomethylene bridges into fused cycloalkyl groups.…”

Section: Resultsmentioning

confidence: 99%

Gaseous cation chemistry and chain‐length effects in electron ionization and collision‐induced dissociation mass spectraof symmetric 1,n‐bis(9‐anthracenyl)alkanes

Schildcrout

Masnovi

2011

J. Mass Spectrom.

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The behavior of the gaseous cations resulting from EI (30 and 70 eV) of the bichromophoric title compounds 1-5 (for n = 1-5, respectively) is examined by ion-trap mass spectrometry, including collision-induced dissociation (CID) with variation in collision energy. These results are compared with those from anthracene and 9-methylanthracene and with previously reported mass spectrometric results for 3 and dicarbazolylalkanes. Rather than using the kinetic method to obtain ion energetics where the fragmentation mechanism is clear, as commonly done, the method is used here with relative complementary-ion abundances from CID to test the proposed fragmentation mechanisms using B3LYP calculations of relative ionization energies and optimized geometries of ionic and neutral fragments. Hydrogen migrations are common, and skeletal rearrangements including formation of expanded, fused and spiro rings are proposed in several cases. Of the chain cleavages, α-homolysis giving C(15) H(11) (+) , likely as dibenzotropylium, is most important for each of 1-5 except 3, where β-cleavage to C(16) H(13) (+) dominates with a proposed methyldibenzotropylium structure. α-Cleavage was important also in the dicarbazolylalkanes. A previous inference of a McLafferty rearrangement to explain C(15) H(12) (+•) from 3 is not supported by the present results. The fragmentation behavior of 1-5 depends strongly on n and implies significant interchromophoric interaction between anthracenyl groups.

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Section: Resultsmentioning

confidence: 99%

Gaseous cation chemistry and chain‐length effects in electron ionization and collision‐induced dissociation mass spectraof symmetric 1,n‐bis(9‐anthracenyl)alkanes

Schildcrout

Masnovi

2011

J. Mass Spectrom.

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“…Emission lifetimes, excited state absorption spectra, and decay kinetics were measured as described previously [23]. Direct excitation cycloreversion quantum yields were determined using the cycloreversion of the photodimer of 1,2-di(9-anthryl)ethane [25] (U CR = 0.55 in benzene) [22] as actinometer. In these experiments the 450 W Xe lamp/monochromator available in our fluorimeter, from which 285 nm excitation was selected, served as the excitation source.…”

Section: Methodsmentioning

confidence: 99%

“…1). [21,22] The UV-vis spectra of 1 and 2 are superimposed in Figure 3a. The d±p* MLCT visible absorption bands of 2 possess quantitatively FULL PAPER similar features (shape and k max ) to [Ru(dmb) 3 ] 2+ .…”

Section: Spectroscopic Characterizationmentioning

confidence: 99%

“…The MLCT-based emission in 1 can be shunted through deep UV photolysis (k < 300 nm), where the anthracene photodimer undergoes cycloreversion, [21,22] forming two molecules of compound 2 with significantly quenched emission, Figure 4. The re-aromatization of anthracene accompanies the cycloreversion photochemistry, generating several absorption bands in vibronic progression just below 400 nm, Figure 4.…”

Section: Photochemical Switchingmentioning

confidence: 99%

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Dinuclear Metal–Organic Material for Binary Optical Recording

Trouts

Tyson

Pohl

et al. 2003

Adv Funct Materials

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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.

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“…Owing to the growing interest on thermal properties of anthracene and anthracene derivative photodimers [1][2][3][4], we re-examined some of our previously published [5][6][7] and unpublished results on this topic. In particular the study of thermal behaviour of such crystalline photodimers allows a division of these compounds into two classes [6]: a) dimers which monomerize at temperatures lower than those of m.p.…”

Section: Introductionmentioning

confidence: 99%