Stereochemistry of selenium- and tellurium-bridged heteromerous bistricyclic aromatic enes. The fluorenylidenechalcoxanthene series

Levy, Amalia; Biedermann, P. Ulrich; Cohen, Shmuel; Agranat, Israel

doi:10.1039/b104858a

Cited by 35 publications

(23 citation statements)

References 26 publications

(72 reference statements)

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“…The syntheses of the BAE-1s 9-(di-1-naphthalenylmethylene)-9H-fluorene (11) and 9-(di-1-naphthalenylmethylene)-9H-xanthene (12) were described [20]. The starting compounds for the syntheses of 11-15 were 1,1 0 -(diazomethylene)bisnaphthylene (26) and 9H-chalcogenoxanthene-9-thiones (27) [42].…”

Section: Methodsmentioning

confidence: 99%

“…The BAEs are attractive substrates for the study of the ground-state properties and dynamic stereochemistry of overcrowded polycyclic aromatic enes (PAEs) and for their thermochromic, photochromic, electrochromic, and piezochromic behavior [2]. The homomerous BAEs dithioxanthylene (4) [10], diselenoxanthylene (5) [11], and ditelluroxanthylene (6) [12] are not thermochromic. Heteromerous derivatives of 2 and 4 and related overcrowded enes serve as candidates for chiroptical molecular switches and molecular motors [13].…”

Section: Introductionmentioning

confidence: 99%

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Variations of bistricyclic aromatic enes: mono-bridged tetraarylethene naphthologs

et al. 2014

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The syntheses, molecular and crystal structures, NMR spectroscopic study, and DFT computational study of naphthologs of mono-bridged (X = -, O, S, Se, and Te) tetraarylethene (BAE-1s) 11-25 with a,a-, b,b-, and a,b-dinaphthalenyl substituents have been reported. The BAE-1s have been prepared by Barton-Kellog twofold extrusion from the respective chalcogenothiones and diazomethylenebisnaphthylenes. Complete assignments of 1 Hand 13 C-NMR spectra of 11-25 have been made through 2-dimensional correlation spectroscopy (DQF-COSY, HSQC, HMBC, and NOESY). The corresponding intermediates, thiiranes 33-47, have been also isolated (except 38), and their molecular and crystal structures have been determined. The molecular structures of BAE-1s 12-15, 20, and 22-25 adopted folded-twisted conformations with considerably folded (u = 30°-57°) tricyclic moieties. The a,a-and a,b-dinaphthalenyl derivatives are more overcrowded than b,b-dinaphthalenyl derivatives. The relief of the steric strain due to the overcrowding around C 9 = C 9 0 caused by the presence of naphthalenyl substituents was achieved by their twisting around the single bonds that connect the a-naphthalenyl and b-naphthalenyl moieties to C 9 0 . The 1 H-NMR spectra have shown shielding of H 2 , H 7 of 11-25 and the pronounced deshielding of H 8 0 , H 8 00 of a,a-dinaphthalenyl-substituted BAE-1s 13-15 in contrast to b,b-dinaphthalenyl-substituted BAE-1s 16-20. The upfield shifts of H 2 , H 7 suggested conformations in which these hydrogens are located above the planes of the opposing naphthalene rings. DFT calculations of 11-20 have been performed at B3LYP/6-31G(d) and B3LYP/ SDD. The results have shown that the global minima of BAE-1s without a chalcogen bridge 11 and 16 are twisted (-sc,-sc)-C 2 -t conformations. The global minima of BAE1s with a chalcogen bridge are folded-twisted (-sc,-ac)-C 1 -ft conformations for a,a-dinaphthalenyl-substituted BAE1s 12-15 and either anti-or syn-(-sc,ac)-C 1 -ft conformations for b,b-dinaphthalenyl-substituted BAE-1s 17-20. The pronounced differences between the a,a-dinaphthalenyl and the b,b-dinaphthalenyl derivatives are noted. Dispersion-corrected B3LYP calculations stabilize significantly the a,a-dinaphthalenyl derivatives versus the b,b-dinaphthalenyl derivatives. The geometrical parameters of BAEs-1 11-15 and 20, derived from their molecular X-ray structures and from their B3LYP-optimized geometries are in a good agreement.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Variations of bistricyclic aromatic enes: mono-bridged tetraarylethene naphthologs

et al. 2014

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“…However the inverse switching occurs only via a thermal pathway. [12] Although the stereochemistry of overcrowded bistricyclic aromatic enylidenes has been extensively studied in the past, [13][14][15] a detailed understanding of their photochemical behavior has not yet been achieved. In particular, it remains unclear why the syn-folded conformer is non-fluorescent whereas the anti-folded conformer emits blue light.…”

Section: Introductionmentioning

confidence: 99%

“…[25] Because this species is separated from the syn-folded 3 B conformer by a low potential energy barrier, about 3 kcal mol À1 , 3 C may be stable only at a sufficiently low temperature. If, however, it were possible to stabilize the twisted conformation, [13,14] this species should be able to emit radiation in the near IR region, at about 740-760 nm [DE S1 ! S0…”

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Theoretical Study of the Photochemistry of a Reversible Three‐State Bis‐Thiaxanthylidene Molecular Switch

Filatov

2011

ChemPhysChem

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The ground- and the lowest singlet excited-state potential energy surfaces of the bis-thiaxanthylidene (3) molecular switch are investigated using a density functional method specifically designed to treat molecular systems typified by strong non-dynamic electron correlation. The results of the theoretical calculations suggest that the unique ability of substituted bis-thiaxanthylidenes to switch between three states of luminescence-non-fluorescent state, blue fluorescent state, and red fluorescent state-can be explained by specific features on the excited state potential energy surface: the potential barrier around the Franck-Condon point of the anti-folded conformer and the existence of conical intersection in the vicinity of the syn-folded conformer. It is suggested that the twisted conformer, if made more stable via chemical modification, should fluoresce in the near-infrared region (λ≈740-760 nm), thus offering a possibility for a four-state switching of luminescence in a single-component molecular system.

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“…This type of structure with a short Te À Te interaction and a polar space group has also been seen for the structure of 9-(9'-H-fluoren-9'-ylidene)-9H-telluroxanthene and could be a more general property of organotellurium compounds. [24] Figure 1. Asymmetric unit cell of the X-ray structure of 9 at 100 K. The fact that all the benzo[c]tellurophene molecules point in the same direction in space introduces a permanent polarization into the crystal, thus prompting us to investigate the pyroelectric properties.…”

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Synthesis, Structure, and Properties of 4,7‐Dimethoxybenzo[c]tellurophene: A Molecular Pyroelectric Material

et al. 2006

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Stereochemistry of selenium- and tellurium-bridged heteromerous bistricyclic aromatic enes. The fluorenylidenechalcoxanthene series

Cited by 35 publications

References 26 publications

Variations of bistricyclic aromatic enes: mono-bridged tetraarylethene naphthologs

Variations of bistricyclic aromatic enes: mono-bridged tetraarylethene naphthologs

Theoretical Study of the Photochemistry of a Reversible Three‐State Bis‐Thiaxanthylidene Molecular Switch

Synthesis, Structure, and Properties of 4,7‐Dimethoxybenzo[c]tellurophene: A Molecular Pyroelectric Material

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