.sigma.-Naphthoquinodimethanes and .sigma.-phenanthroquinodimethanes. Isoindene-related species

Dulcere, Jean Pierre; Sellers, Simon F.; Koroniak, Henryk; Shatkin, Blane T.; Clark, Thomas L.

doi:10.1021/jo00133a013

Cited by 12 publications

(3 citation statements)

References 5 publications

(10 reference statements)

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“…Its reaction with tribromophosphane furnished the bromo derivative 7 in 81% yield. 19 8 was finally afforded in 62% yield after lithiation of CPDT 16b,20 at position 4, followed by a reaction with 7.…”

Section: Resultsmentioning

confidence: 99%

Electropolymerisable ruthenium(ii) phenanthrolines carrying azacrown ether receptors: metal ion recognition in thin film redox sensors

Schmittel

Lin

2008

J. Mater. Chem.

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The tris(1,10-phenanthroline)ruthenium(II) complexes 1-3 (with 0, 4 and 2 appended azacrown ether units, respectively) linked via alkyl chains to 4H-cyclopenta[2,1-b:3,4-b9]dithiophene (CPDT) were synthesised, characterised and immobilised on Pt and ITO electrodes through electropolymerisation. The electrochemical, UV-vis absorption and metal ion recognition properties of the thus modified electrodes were investigated in detail. Immobilisation of 2 on electrodes was only feasible in a copolymerisation with the parent CPDT. The copolymer film poly(2 + CPDT) exhibited sensitivity for Ba 2+ and Pb 2+ in cyclic voltammetry investigations. At milli-and micromolar concentrations of Ba 2+ and Pb 2+ , respectively, a redox potential shift of more than 200 mV was found in MeCN. 3 was electropolymerised on electrodes directly and the resulting thin film of poly(3) showed similar redox potential shifts for Ba 2+ and Pb 2+ (around 150 mV) with a higher sensitivity for Pb 2+ than Ba 2+ .

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Section: Resultsmentioning

confidence: 99%

Electropolymerisable ruthenium(ii) phenanthrolines carrying azacrown ether receptors: metal ion recognition in thin film redox sensors

Schmittel

Lin

2008

J. Mater. Chem.

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“…Formation of less-strained six-membered ring isomer 15 over the other possible five-membered ring isomers 16 and 17 in the Friedel−Crafts (FC) reaction is expected to be thermodynamically more favorable. However, Dolbier et al have shown that the solvent has a dramatic effect on the product distribution in FC reaction of this type of substrates . The compound 15 was characterized by its symmetrical 1 H and 13 C NMR spectral data.…”

Section: Resultsmentioning

confidence: 99%

“…However, Dolbier et al have shown that the solvent has a dramatic effect on the product distribution in FC reaction of this type of substrates. 14 The compound 15 was characterized by its symmetrical 1 H and 13 C NMR spectral data. The other two isomers were also identified on the basis of 1 H NMR spectral data.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Indan-Based Unusual α-Amino Acid Derivatives under Phase-Transfer Catalysis Conditions

Kotha

Brahmachary

2000

J. Org. Chem.

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Conformationally constrained cyclic alpha-amino acid derivatives were synthesized under solid-liquid phase-transfer catalysis conditions. This methodology involves the bis-alkylation of ethyl isocyanoacetate with various alpha,alpha'-dibromo-o-xylene derivatives [alpha,alpha'-dibromo-o-xylene 5, 2,3-bis(bromomethyl)-1, 4-dimethoxybenzene 6, 1,2-bis(bromomethyl)-4,5-dibromobenzene 7, 2, 3-bis(bromomethyl)naphthalene 8, 1,8-bis(bromomethyl)-naphthalene 9, 6,7-bis(bromomethyl)-2,2-dimethyl-1H-phenalene-1,3(2H)-dione 10, 2, 3-bis(bromomethyl)-1,4-anthraquinone 11, 6, 7-bis(bromomethyl)quinoxaline 12, 3,4-bis(bromomethyl)furan 13, 1,2, 4,5-tetrakis(bromomethyl)benzene 28, and hexakis(bromomethyl)benzene 30] using potassium carbonate as a base and tetrabutylammonium hydrogensulfate as a phase-transfer catalyst to give corresponding isonitrile derivatives, which upon hydrolysis with HCl in ethanol gave amino esters. Using this method electron-deficient as well as electron-rich and halogen-substituted indan-based alpha-amino acids were prepared. The preparation of bis-indan as well as tris-indan alpha-amino esters is also described.

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Electron‐Transfer Reactions Triggered by Uncharged or Cationic Photosensitizer: Methodology for Generation of o‐Quinodimethane and Analysis of Back Electron‐Transfer Process

et al. 2017

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Photoinduced electron transfer (PET) followed by back electron transfer (BET) reactions of 1,2-bis(a-styryl)benzenes 1,g enerates o-quinodimethane derivative 2 via the corresponding radical cation 2 · + .T his process serves as af acile methodt of orm o-quinodimethane intermediates. The intermediacy of 2 · + and 2 werec onfirmed by using various spectroscopicm ethods and trapping reactions with 3 O 2 and dienophiles. Kinetic analysisu sing nanosecond time-re-solved absorption showed that 2 · + was transformed to 2 via aB ET process, in which the decay of 2 · + and rise of 2 have almostt he same rate constants of k DECAY = 5.6 10 5 s À1 and k RISE = 5.9 10 5 s À1 ,r espectively.T he net BET rate constant evaluated by using Marcus theory is much faster than these experimental values, owing to the reduction based on diffusion.[a] Prof.form (M · + + +A · )a nd thes econdE Ti n( D + +M · + )f orms (D · + + +M). Ther esulting long distance betweenD · + andA · effectivelyp reventsf ormationo f[ D · + //A · ], thereforet he lifetime of D · + is substantially extended.I nt erms of analyzingt he BETp rocess, the most importanti nt hise fforti sB ET between( D · + + +A · ), whichi s formed in theP ET reactionss hown in Scheme 1b and1 c. As showni nS cheme1d, ther atec onstant (k BET )i sd efined fort he BETreactioni nt he encounterc omplex [D · + //A · ] EC that relatest o theassociation anddissociationof(D · + + A · ).Uncharged organic sensitizers, such as 9,10-dicyanoanthracene (DCA, Figure 1) and 1,4-dicyanonaphthalene (DCN), are conventional. Typical cationic sensitizers such as N-methylquinoliniumt etrafluoroborate (NMQ + BF 4 À ), [6] 2,4,6-triphenylpyrylium tetrafluoroborate( TPP + BF 4 À ), and N-methyl-9-mesitylacridinium perchlorate (Mes-Acr + ClO 4 À ,F ukuzumip hotocatalyst 7 ) can promote reactions of free D · + .R ecently,o rganometallic complexes,s uch as Ru(bpy) 3 2 + (Cl À ) 2 and fac-Ir(ppy) 3 ,h ave also been used in organic synthesis. [8] Upon excitation by visible light, these complexes undergo intersystem crossing to form long-lived triplet excited states.T he long lifetime induces ah igh possibility of collision with D, while the triplet state at alow energy level results in relatively low oxidation ability. g-Irradiationi naspecific solvent can also induce ET without any sensitizer and is often used forspectroscopic measurements.Kinetic analysiss uch as Stern-Volmer analysis is ap owerful tool to examine the synthetics tudy on aP ET reaction. When using an on-fluorescents ensitizer,l aser flash photolysis (LFP) provides informationa bout the formation and decay of D · + (Figure 2a). However, information on the recovery of Db yB ET,

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.sigma.-Naphthoquinodimethanes and .sigma.-phenanthroquinodimethanes. Isoindene-related species

Cited by 12 publications

References 5 publications

Electropolymerisable ruthenium(ii) phenanthrolines carrying azacrown ether receptors: metal ion recognition in thin film redox sensors

Electropolymerisable ruthenium(ii) phenanthrolines carrying azacrown ether receptors: metal ion recognition in thin film redox sensors

Synthesis of Indan-Based Unusual α-Amino Acid Derivatives under Phase-Transfer Catalysis Conditions

Electron‐Transfer Reactions Triggered by Uncharged or Cationic Photosensitizer: Methodology for Generation of o‐Quinodimethane and Analysis of Back Electron‐Transfer Process

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