Molecular Saddles. 4. 1 Redox-Active Cyclophanes by Bridging the 9,10-Bis(1,3-dithiol-2-ylidene)-9,10-dihydroanthracene System: Synthesis, Electrochemistry, and X-ray Crystal Structures of Neutral Species and a Dication Salt (original) (raw)
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Chemische Berichte, 1990
The syntheses of 2,11-dithia[3.3]orthometacyclophane (5) and 2,l l-dithia[3.3]orthoparacyclophane (6) by dithiol-dibromide coupling are described. Whereas the yield of 5 is not significantly affected by the substrate pairing, that of 6 is. Both cornpounds exhibit a temperature-dependent 'H-NMR spectrum. An energy barrier of 11.0 f 0.2 kcal/mol (45.7 f 0.8 kJ/mol) has been calculated for 5, but that of 6 was too low to be determined. Slightly contrasting results were obtained from two different molecular mechanics programs for the relative energies of the six limiting conformations of 5. Crystal structure determinations of 5 and 6 have been carried out, and the conformational behavior of 5 and 6 in solution and in the solid state is discussed.
Tetrahedron, 2008
Oxa-bridged cyclophanes 4/6 and 8/10 featuring thieno[2,3-b]thiophene ring and binol or bis-naphthol have been synthesized. The structures are assigned by 2D NMR data and the identity of 4 is also independently established by a single X-ray crystallography. From dynamic NMR analysis, the Arrhenius energy of activation DG # for bridge inversions in 4 and 6 was calculated to be 15.3 and 12.9 kcal/mol, respectively. A higher DG # for 4, relative to the ester free 6 is attributable to the steric compression stemming from C2/C5 ester substituents to the bridge inversion processes. While the methylene bridges undergo inversion in 4 and 6, the naphthyl-naphthyl pseudo-rotation appears to be restricted even at higher temperatures. This is supported by retention of the optical purity of the chiral (À) 4 under thermal condition. For the case of bis-naphthol cyclophane 8, we observed the flipping of both the -OCH 2 -and the naphthyl-CH 2 -naphthyl bridges with DG # of ca. 11.4 kcal/mol. However, the ester free cyclophane 10 remained conformationally mobile even at À55 C and its DG # was assumed to be <11.4 kcal/mol. The presence of an extra -CH 2 -linker in bis-naphthol cyclophanes 8/10 renders them relatively more conformationally mobile compared to binol cyclophanes 4/6, possessing a rigid naphthyl-naphthyl geometry.
Beilstein Journal of Organic Chemistry, 2009
The synthesis of [3.3]dithia-bridged cyclophanes 7, 9 and 11 incorporating a fused heterocycle, thieno[2,3-b]thiophene is described. The structures are established by 1H NMR analysis and, in the case of 11, also by single crystal X-ray crystallography. Conformational analysis by variable temperature NMR suggests that cyclophanes 7, 9 and 11 exhibit conformationally rigid bridges and rings at least up to 130 °C. Energy minimization of 11 revealed anti -11 to be the most stable conformation. Although, the computed energy difference between the most stable conformation anti -11 and the next higher energy conformation syn-anti -11 is only 2.98 kJ/mol, it is intriguing that 11 does not exhibit thia-bridge inversion even at elevated temperatures.
New [4.4]Cyclophane Diketals, Monoketones, and Diketones: Design, Synthesis, and Structural Analysis
European Journal of Organic Chemistry, 2007
The synthesis of some new [4.4]cyclophane diketals, monoketones, and diketones in good yields is reported along with the unusually low reactivity towards hydrolysis of the spiro-1,3-dioxane rings connected to the cyclophane bridges. The structural analysis carried out by X-ray diffraction, NMR spectroscopy, and mass spectrometry shows significant intra-
Tetrahedron Letters, 1981
The synthesis of syn-and anti-9-methyl-18-phenyl-and anti-g, 18-diphenyl2,11dithia[3,3]metacyclophanes is described, together with their variable temperature 'Hmr spectra. Only partial rotation of the phenyl substituents (ACT -50 k.J. mol-') is believed to occur. The synthesis and stereochemical aspects of cyclophanes have been of particular interest over the last two decades. 2 More recently, the size of internal substituents X, Y, in [2,2] metacyclophanes 1 and 2,ll lithia [3,3]metacyclophanes
Synthesis and conformational studies of 9-methoxy- and 9-methyl-2,11-dithia[3.3]metacyclophanes
Journal of Chemical Research, 2009
A series of 9-methoxy- and 9-methyl-2,11-dithia[3.3]metacyclophanes are obtained by the coupling reaction of the corresponding 1,3-bis(bromomethyl)benzenes and bis(sulfanylmethyl)benzenes in ethanol under the high dilution conditions. The conformational studies of 2,11-dithia[3.3]metacyclophanes as well as the ring current interactions derived from benzene ring are also described.
Chemistry, 2001
Flash photolysis of bis [4,5di(methylsulfanyl)1,3-dithiol-2-ylidene]-9,10-dihydroanthracene (1) in chloroform leads to formation of the transient radical cation species 1 . which has a diagnostic broad absorption band at l max % 650 nm. This band decays to half its original intensity over a period of about 80 ms. Species 1 . has also been characterised by resonance Raman spectroscopy. In degassed solution 1 . dis-proportionates to give the dication 1 2 , whereas in aerated solutions the photodegradation product is the 10-[4,5-di-(methylsulfanyl)1,3-dithiol-2-ylidene]anthracene-9(10 H)one (2). The dication 1 2 has been characterised by a spec-troelectrochemical study [l max (CH 2 Cl 2 ) 377, 392, 419, 479 nm] and by an X-ray crystal structure of the salt 1 2 (ClO 4 À ) 2 , which was obtained by electrocrystallisation. The planar anthracene and 1,3-dithiolium rings in the dication form a dihedral angle of 77.28; this conformation is strikingly different from the saddle-shaped structure of neutral 1 reported previously.
A novel dithioferrocenophane with a vic-dioxine moiety in the bridging chain
Journal of Organometallic Chemistry, 1987
The amphi and anti isomers of 1,4-dithia-2,3-bis(hydroxyimino)[4](l,l')ferrocenophane were prepared by the reaction of disodium l,l'-ferrocenedithiolate with anti-dichloroglyoxime. The Ni" complex of the amphi isomer was also isolated and characterized. * Dedicated to Prof. H.A. Staab on the occasion of his 60th birthday. 0022-328X/87/$03.50 0 1987 Elsevier Sequoia S.A.
Synthesis and Structural Study of Thiacyclophanes Utilizing Dibromides and Methane Dithiolate
Journal of Organic Chemistry, 2005
The synthesis of a series of thiacyclophanes and optically active binaphthol-based chiral thiacyclophanes is reported with XRD structure. Two diastereomeric tetrathiacyclophanes are designed and synthesized. The two diastereomers are evidenced by crystal structure; the single-crystal X-ray studies reveal that one of the isomers possesses an inherent property of self-assembling into a vertical stack of tunnellike structures.
The Journal of Organic Chemistry, 2008
The fair or good yield synthesis of new [(4.4) n ]cyclophanes (n ) 1-5), starting from 1,4-bis(2hydroxymethyl-5,5-dimethyl-1,3-dioxan-2-yl)benzene and several diacid-dichlorides, based on monomer and oligomer formation reactions (from 1 + 1 to 5 + 5), is reported. The structure and the complex architectures of the lattices for these cyclophanes are revealed by the X-ray molecular structure for five compounds, NMR investigations, and mass spectrometry measurements. Intramolecular and intermolecular CH-π, p-π, and π-π interactions are observed, both in solid state and solution. (1) In the nomenclature of [m. n]cyclophanes m and n represent the numbers of atoms in the bridges; for the nomenclature of cyclophanes, see: Vögtle, F. Yun, S.; Hong, B. H.; Kim, Y.-O.; Kim, D.; Ihm, H.; Lee, J. W.; Lee, E. C.; Tarakeshwar, P.; Park, S.-M.; Kim, K. S. Org.