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Hiroshi Sano - One of the best experts on this subject based on the ideXlab platform.
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proline catalyzed asymmetric diels alder reactions of an o Quinodimethane
ChemInform, 2014Co-Authors: Hidenori Shirakawa, Hiroshi SanoAbstract:A highly diastereo- and enantioselective Diels—Alder reaction of the new precursor α-amino-o-Quinodimethane with α,β-unsaturated aldehydes is achieved in the presence of L-proline.
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proline catalyzed asymmetric diels alder reactions of an o Quinodimethane
Tetrahedron Letters, 2014Co-Authors: Hidenori Shirakawa, Hiroshi SanoAbstract:Catalytic asymmetric Diels–Alder reaction of α-amino-o-Quinodimethane with α,β-unsaturated aldehydes was achieved with high diastereo- and enantioselectivities in the presence of l-proline, which acts as a promoter to generate the Quinodimethane from the corresponding precursor as well as a chiral catalyst for the enantioselective Diels–Alder reaction.
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2 trimethylsilyl methyl benzyl methanesulfonates useful precursors for the generation of o Quinodimethanes
Synthesis, 2014Co-Authors: Hidenori Shirakawa, Hiroshi SanoAbstract:2-[(Trimethylsilyl)methyl]benzyl methanesulfonates react with potassium fluoride in the presence of a catalytic amount of 18-crown-6 at room temperature to give o-Quinodimethanes, which are trapped with electron-deficient olefins to afford [4+2] cycloadducts in good yields.
Paolo Melchiorre - One of the best experts on this subject based on the ideXlab platform.
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asymmetric catalysis of diels alder reactions with in situ generated heterocyclic ortho Quinodimethanes
ChemInform, 2012Co-Authors: Manuel Nappi, Elena Arceo, Silvia Vera, Paolo MelchiorreAbstract:Under catalysis of a chiral amine, the title Quinodimethanes are generated in situ to further undergo Diels—Alder reactions with nitroolefins or methyleneindolinones to give carbazole-, pyrrole-, or furan-based cycloadducts with excellent stereoselectivities.
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Multicatalytic Asymmetric Synthesis of Complex Tetrahydrocarbazoles via a Diels–Alder/Benzoin Reaction Sequence
Organic letters, 2012Co-Authors: Yankai Liu, Manuel Nappi, Eduardo C. Escudero-adán, Paolo MelchiorreAbstract:Expanding upon the recently developed aminocatalytic asymmetric indole-2,3-Quinodimethane strategy, a straightforward synthesis of structurally and stereochemically complex tetrahydrocarbazoles has been devised. The chemistry’s complexity-generating power was further harnessed by designing a multicatalytic, one-pot Diels–Alder/benzoin reaction sequence to stereoselectively access trans-fused tetracyclic indole-based compounds having four stereogenic centers with very high fidelity.
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multicatalytic asymmetric synthesis of complex tetrahydrocarbazoles via a diels alder benzoin reaction sequence
Organic Letters, 2012Co-Authors: Yankai Liu, Manuel Nappi, Eduardo C Escuderoadan, Paolo MelchiorreAbstract:Expanding upon the recently developed aminocatalytic asymmetric indole-2,3-Quinodimethane strategy, a straightforward synthesis of structurally and stereochemically complex tetrahydrocarbazoles has been devised. The chemistry’s complexity-generating power was further harnessed by designing a multicatalytic, one-pot Diels–Alder/benzoin reaction sequence to stereoselectively access trans-fused tetracyclic indole-based compounds having four stereogenic centers with very high fidelity.
Chunyan Chi - One of the best experts on this subject based on the ideXlab platform.
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a tetraindeno fused bis anthraoxa Quinodimethane with nine consecutively fused six membered rings
Organic Letters, 2021Co-Authors: Johnathan Joo Cheng Lee, Yi Han, Shaoqiang Dong, Albert Ong, Chunyan ChiAbstract:A tetraindeno-fused bis(anthraoxa)Quinodimethane RBR with nine consecutively fused six-membered rings in a row was synthesized. Its structure was confirmed by X-ray crystallographic analysis and NMR measurement. Compared with an unfused analogue ABA, the indeno fusion onto the zigzag edges not only enhanced the photostability but also dramatically tuned the electronic properties. Due to the existence of two rubicene units, RBR can also be readily reduced to form a radical anion and dianion.
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sulfur containing Quinodimethane embedded acene analogue with nine consecutively fused six membered rings
Organic Letters, 2019Co-Authors: Yang Chen, Huilin Kueh, Tullimilli Y Gopalakrishna, Shaoqiang Dong, Yi Han, Chunyan ChiAbstract:Linear Quinodimethane-embedded acene analogue 9L was synthesized, and its quinoidal structure was confirmed by X-ray crystallographic analysis. The multiple oxidation states of 9L could be achieved. Its dication is a triplet diradical, and its tetracation can be regarded as the isoelectronic structure of the nonacene, which was validated by experiments and theoretical calculations.
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Sulfur-Containing, Quinodimethane-Embedded Acene Analogue with Nine Consecutively Fused Six-Membered Rings
2019Co-Authors: Yang Chen, Huilin Kueh, Tullimilli Y Gopalakrishna, Shaoqiang Dong, Yi Han, Chunyan ChiAbstract:Linear Quinodimethane-embedded acene analogue 9L was synthesized, and its quinoidal structure was confirmed by X-ray crystallographic analysis. The multiple oxidation states of 9L could be achieved. Its dication is a triplet diradical, and its tetracation can be regarded as the isoelectronic structure of the nonacene, which was validated by experiments and theoretical calculations
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a p Quinodimethane bridged porphyrin dimer
Chemistry: A European Journal, 2013Co-Authors: Wangdong Zeng, Zebing Zeng, Masatoshi Ishida, Young Mo Sung, Chunyan Chi, Sangsu Lee, Dongho KimAbstract:A p-Quinodimethane (p-QDM)-bridged porphyrin dimer 1 has been prepared for the first time. An unexpected Michael addition reaction took place when we attempted to synthesize compound 1 by reaction of the cross-conjugated keto-linked porphyrin dimers 8 a and 8 b with alkynyl/aryl Grignard reagents. Alternatively, compound 1 could be successfully prepared by intramolecular Friedel–Crafts alkylation of the diol-linked porphyrin dimer 14 with concomitant oxidation in air. Compound 1 shows intense one-photon absorption (OPA, λmax=955 nm, e=45400 M−1 cm−1) and a large two-photon absorption (TPA) cross-section (σ(2)max=2080 GM at 1800 nm) in the near-infrared (NIR) region due to its extended π-conjugation and quinoidal character. It also exhibits a short singlet excited-state lifetime of 25 ps. The cyclic voltammogram of 1 displays multiple redox waves with a small electrochemical energy gap of 0.86 eV. The ground-state geometry, electronic structure, and optical properties of 1 have been further studied by density functional theory (DFT) calculations and compared with those of the keto-linked dimer 8 b. This research has revealed that incorporation of a p-QDM unit into the porphyrin framework had a significant impact on its optical and electronic properties, leading to a novel NIR OPA and TPA chromophore.
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pushing extended p Quinodimethanes to the limit stable tetracyano oligo n annulated perylene Quinodimethanes with tunable ground states
Journal of the American Chemical Society, 2013Co-Authors: Zebing Zeng, Masatoshi Ishida, Jose L Zafra, Xiaojian Zhu, Young Mo Sung, Nina Bao, Richard D Webster, Byung Sun Lee, Wangdong Zeng, Chunyan ChiAbstract:p-Quinodimethane (p-QDM) is a fundamental building block for the design of π-conjugated systems with low band gap and open-shell biradical character. However, synthesis of extended p-QDMs has usually suffered from their intrinsic high reactivity and poor solubility. In this work, benzannulation together with terminal cyano-substitution was demonstrated to be an efficient approach for the synthesis of a series of soluble and stable tetracyano-oligo(N-annulated perylene)Quinodimethanes nPer-CN (n = 1–6), with the longest molecule having 12 para-linked benzenoid rings! The geometry and electronic structures of these oligomers were investigated by steady-state and transient absorption spectroscopy, nuclear magnetic resonance, electron spin resonance, superconducting quantum interference device, and FT Raman spectroscopy assisted by density functional theory calculations. They showed tunable ground states, varying from a closed-shell quinoidal structure for monomer, to a singlet biradical for dimer, trimer, an...
Mohamed R Saber - One of the best experts on this subject based on the ideXlab platform.
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magnetic coupling between metal spins through the 7 7 8 8 tetracyanoQuinodimethane tcnq dianion
Chemistry: A European Journal, 2014Co-Authors: Mohamed R Saber, Andrey V Prosvirin, Brendan F Abrahams, Robert W Elliott, Richard Robson, Kim R DunbarAbstract:A family of magnetic metal-organic frameworks, (Ph3PMe)2� (M2(TCNQ)3 ){ M= Fe 2 + ,C o 2 + ,N i 2 + and Zn 2 + } have been prepared and structurally characterized. The honeycomb-like "layers" consist of M II ions doubly bridged with dinitrilomethane moieties of two 7,7,8,8-tetracyano- Quinodimethane (TCNQ) dianion and further extend through phenyl rings to form 3D dianionic framework (M2TCNQ3) 2� with Ph3PMe + cations filling cavities that run
Joel S Miller - One of the best experts on this subject based on the ideXlab platform.
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theoretical study of the electronic structure of tcnq 2 2 tcnq 7 7 8 8 tetracyano p Quinodimethane dimers and their intradimer long multicenter bond in solution and the solid state
Journal of Physical Chemistry A, 2009Co-Authors: Inigo Garciayoldi, Joel S Miller, Juan J NovoaAbstract:The long, multicenter bonding in 7,7,8,8-tetracyano-p-Quinodimethane anion radical dimers, [TCNQ]22−, observed in both the solid state and in solution, was computationally investigated via B3LYP, C...
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iron pentacarbonyl as a precursor for molecule based magnets formation of fe tcne 2 tc 100 k and fe tcnq 2 tc 35 k magnets
Inorganic Chemistry, 2002Co-Authors: Konstantyn I Pokhodnya, Nate Petersen, Joel S MillerAbstract:The reaction of tetracyanoethylene (TCNE) and 7,7,8,8-tetracyano-p-Quinodimethane (TCNQ) with Fe(CO)5 leads to formation of magnetically ordered materials of Fe[TCNE]2 (Tc = 100 K) and Fe[TCNQ]2 (T...
