Diastereoselective reaction of (MP)-pentahelicene-7,8-dione with trans-cyclohexane-1,2-diamine. Thermal and photochemical transformations of its product

Putala, Martin; Kastner-Pustet, Nikola; Mannschreck, Albrecht

doi:10.1016/s0957-4166(02)00014-9

Cited by 13 publications

(5 citation statements)

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“…In the same trend, the synthesis of [5]helicene-7,8-quinone was reported along with a diastereoselective reaction with 247 Accordingly, this oxidation could lead to a variety of helicene derivatives. A simpler reaction with cyclohexane-1,2dione afforded the corresponding pyrazine ring in the final product, as shown in Scheme 76.…”

Section: Post-functionalization Of Carbohelicenes: Selected Examplesmentioning

confidence: 73%

“…A simpler reaction with cyclohexane-1,2dione afforded the corresponding pyrazine ring in the final product, as shown in Scheme 76. 247 Among those methods, the Gingras' group enlightened the uses of ''benzylic couplings'' for producing an important amount (several grams) of mono-and dibrominated [5]helicene precursors. 128,129,130 A list of reactions with 7-bromo- [5]helicene is presented in Scheme 77.…”

Section: Post-functionalization Of Carbohelicenes: Selected Examplesmentioning

confidence: 99%

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One hundred years of helicene chemistry. Part 1: non-stereoselective syntheses of carbohelicenes

2013

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Carbohelicenes belong to a class of fascinating, chiral, and helicoidal molecules, which have a rich history in chemistry since the very beginning of the 20th century. A renewed interest in polyaromatic chemistry and new synthetic challenges toward the search for innovative physical, biological, chemical and opto-electronic properties have brought high motivation in this field of studies. Theoretical insights gained from polyaromatic, chiral, conjugated and distorted π-systems are also responsible for this development. Several synthetic avenues were originally reported for making lower helicenes, but for many years, photochemical synthesis has remained a major method for producing small amount of helicenes. High-dilution conditions is still a limiting factor in their synthesis. The fulgurous impact of organometallic chemistry, novel synthetic methods, and recent catalytic systems has promoted the development of helicene chemistry, toward a library of tailor-made and highly functionalized helicene molecules. Helicene chemistry is being considered as an expanding and modern field, leading to several applications in supramolecular chemistry, in nanosciences, in chemical-biology, in polymers and materials science. This first part of a series of three reviews on carbohelicenes will be devoted to a comprehensive report on non-stereoselective reactions and methods for producing helicenes, along with their functionalization.

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Section: Post-functionalization Of Carbohelicenes: Selected Examplesmentioning

confidence: 73%

Section: Post-functionalization Of Carbohelicenes: Selected Examplesmentioning

confidence: 99%

One hundred years of helicene chemistry. Part 1: non-stereoselective syntheses of carbohelicenes

2013

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“…All manipulations were performed under aerobic conditions using materials (reagent grade) and solvents as received unless otherwise noted. The organic ligands phenoxH and phendoxH 2 were prepared and characterized according to modified literature methods described elsewhere. , Infrared spectra were recorded in the solid state on a Bruker’s FT-IR spectrometer (ALPHA’s Platinum ATR single reflection) in the 4000–400 cm –1 range. Elemental analyses (C, H, and N) were performed on a PerkinElmer 2400 Series II Analyzer.…”

Section: Experimental Sectionmentioning

confidence: 99%

Oximato-Based Ligands in 3d/4f-Metal Cluster Chemistry: A Family of {Cu₃Ln} Complexes with a “Propeller”-like Topology and Single-Molecule Magnetic Behavior

et al. 2018

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The organic chelating and bridging ligands 9,10-phenanthrenedione-9-oxime (phenoxH) and 9,10-phenanthrenedione-9,10-dioxime (phendoxH2) were synthesized and subsequently employed for the first time in heterometallic 3d/4f-metal cluster chemistry. The general reaction between CuCl2·2H2O, LnCl3·6H2O, phenoxH, and NEt3 in a 1:2:2:4 molar ratio, in a solvent mixture comprising MeCN and MeOH, afforded brown crystals of a new family of [Cu3LnCl3(phenox)6(MeOH)3] clusters (Ln = Gd (1), Tb (2), Dy (3)) that possess an unprecedented [Cu3Ln(μ-NO)6]3+ “propeller”-like core. Complexes 1–3 are the first {Cu3Ln} clusters in which the outer CuII and the central LnIII atoms are solely bridged by diatomic oximato bridges. The {Cu-N-O-Ln} bridging units are very distorted with torsion angles spanning the range 35.5–48.9° and 25.2–55.6° in 1 and 2, respectively. As a result, complexes 1–3 are antiferromagnetically coupled, in agreement with previously reported magnetostructural criteria for oximato-bridged Cu/Ln complexes. The magnetic susceptibility data for all complexes were nicely fit to an isotropic spin Hamiltonian (for 1) or a Hamiltonian that accounts for the spin of the CuII atoms, the spin component of the LnIII, the spin–orbit coupling (λ), an axial ligand-field component around the LnIII atoms (Δ), and the Zeeman effect (for the anisotropic 2 and 3). The resulting fit parameters were J = −1.34 cm–1 and g = 2.10 (1), J = −1.42 cm–1, g Cu = 2.10, and Δ = −26.3 cm–1 (2), and J = −1.70 cm–1, g Cu = 2.05, and Δ = −38.1 cm–1 (3). The reported fitting procedure, implemented in the PHI program, is here used for the first time. Even if this method is only valid in high-symmetry Ln environments, when it is properly used allows a very simple and efficient method to obtain the exchange parameters. In light of the negative anisotropy, compounds 2 and 3 were found to exhibit frequency-dependent tails of out-of-phase signals in the presence of a small external dc field, characteristic of the slow magnetization relaxation of a single-molecule magnet. By using the Kramers–Kronig equations, the effective energy barriers (U eff) were derived and reported as U eff = 10.1 and 5.4 cm–1 for 2 and 3, respectively.

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“…2, 4, 5, and 6) are good indications of high peak purities as far as impurities are concerned that absorb at the wavelengths applied. It turned out in our laboratory that double detection and eventual deconvolution may serve for qualitative routine analysis of synthetic mixtures, e.g., from condensation reactions 35 or cycloadditions, 1 particularly with reference to the distinction between chiral and achiral species.…”

Section: Purities Of Chromatographic Peaksmentioning

confidence: 99%

Chiroptical detection during liquid chromatography: Deconvolution of overlapping peaks of enantiomers and its applications

et al. 2003

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The peaks of enantiomers in liquid chromatography (LC) frequently overlap for different reasons. The experimental curve can be deconvolved, i.e., transformed into the two curves of the enantiomers, without any assumption concerning their peak shapes. Besides the usual photometric UV detection, resulting in absorbance A, polarimetric or circular dichroic detection is required, providing the rotation 90 degree angle alpha or the differential absorbance DeltaA, respectively. The accuracy of the ratio alpha/A or DeltaA/A for the pure enantiomers is essential for the quality of the deconvolution. The determination of these ratios, using the overlapping peaks, and the subsequent computer deconvolution of the latter are discussed in more detail than in the earlier publications, e.g. Ref. 1 concerning this particular method. The computer program developed for this purpose is characterized. A condition is given which limits the availability of ratios and, therefore, the possibility of deconvolution. Several novel examples are described which stem from the following fields of application of deconvolved peaks: actual optical purities during LC (on-line analysis), overall optical purity of a sample, purities of chromatographic peaks, and, finally, enantiomerization during LC.

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Diastereoselective reaction of (MP)-pentahelicene-7,8-dione with trans-cyclohexane-1,2-diamine. Thermal and photochemical transformations of its product

Cited by 13 publications

References 17 publications

One hundred years of helicene chemistry. Part 1: non-stereoselective syntheses of carbohelicenes

One hundred years of helicene chemistry. Part 1: non-stereoselective syntheses of carbohelicenes

Oximato-Based Ligands in 3d/4f-Metal Cluster Chemistry: A Family of {Cu₃Ln} Complexes with a “Propeller”-like Topology and Single-Molecule Magnetic Behavior

Chiroptical detection during liquid chromatography: Deconvolution of overlapping peaks of enantiomers and its applications

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Diastereoselective reaction of (MP)-pentahelicene-7,8-dione with trans-cyclohexane-1,2-diamine. Thermal and photochemical transformations of its product

Cited by 13 publications

References 17 publications

One hundred years of helicene chemistry. Part 1: non-stereoselective syntheses of carbohelicenes

One hundred years of helicene chemistry. Part 1: non-stereoselective syntheses of carbohelicenes

Oximato-Based Ligands in 3d/4f-Metal Cluster Chemistry: A Family of {Cu3Ln} Complexes with a “Propeller”-like Topology and Single-Molecule Magnetic Behavior

Chiroptical detection during liquid chromatography: Deconvolution of overlapping peaks of enantiomers and its applications

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Oximato-Based Ligands in 3d/4f-Metal Cluster Chemistry: A Family of {Cu₃Ln} Complexes with a “Propeller”-like Topology and Single-Molecule Magnetic Behavior