Advancements in the mechanistic understanding of the copper-catalyzed azide–alkyne cycloaddition

• Regina Berg and
• Bernd F. Straub

Beilstein J. Org. Chem. 2013, 9, 2715–2750, doi:10.3762/bjoc.9.308

• (1 mol %) and TBTA (1 mol %) under aerobic conditions [64]. Cyclic voltammetry measurements have supported the hypothesis of TBTA influencing the redox activity of copper(I), as the redox potential of the Cu(I)/Cu(II) pair was shown to rise by approximately 300 mV when the water-soluble derivative

Stability of SG1 nitroxide towards unprotected sugar and lithium salts: a preamble to cellulose modification by nitroxide-mediated graft polymerization

• Guillaume Moreira,
• Laurence Charles,
• Mohamed Major,
• Florence Vacandio,
• Yohann Guillaneuf,
• Catherine Lefay and
• Didier Gigmes

Beilstein J. Org. Chem. 2013, 9, 1589–1600, doi:10.3762/bjoc.9.181

• and are listed in Table 1. The cyclic voltammograms of SG1 and LiCl in DMF and MeOH are presented in Figure 10. The redox potential of the reduction of Li+/Li in DMF is around −2.1 V as already reported [31]. Initially only the SG1 nitroxide, Li+ and Cl− were present in the media. The only possible

• of the solvent (DMF or DMA) with the lithium salt (LiCl or LiBr). The first hypothesis to explain the SG1 consumption in DMA/LiCl was based on the SG1 oxidation by Cl2 (or Br2 in the case of LiBr lithium salt). However, the study by cyclic voltammetry of the redox potential of SG1 and LiCl could not

• reactive, but all regioisomers are possible. (Reversible) redox system of nitroxide. Hydrolysis of DMA in the presence of LiCl. Disproportionation of nitroxide 1 by acid treatment. Experimental redox potential of the oxidation (Eox) and of the reduction (Ered) in DMF and MeOH.a Acknowledgements The

Metal-free aerobic oxidations mediated by N-hydroxyphthalimide. A concise review

• Lucio Melone and
• Carlo Punta

Beilstein J. Org. Chem. 2013, 9, 1296–1310, doi:10.3762/bjoc.9.146

• yields. Enzyme laccase Enzyme laccase is a family of “blue-copper” oxidase proteins, containing four copper ions in the active site, which cooperates in the degradation of the biopolymer lignin in woody tissues. With respect to other powerful oxidant enzymes, laccase has a lower redox potential. For this

Simple and rapid hydrogenation of p-nitrophenol with aqueous formic acid in catalytic flow reactors

• Rahat Javaid,
• Shin-ichiro Kawasaki,
• Akira Suzuki and
• Toshishige M. Suzuki

Beilstein J. Org. Chem. 2013, 9, 1156–1163, doi:10.3762/bjoc.9.129

• stabilized against precipitation by complex formation with EDTA and NH3, which also controls the deposition rate of the individual metal by modifying the redox potential [33]. SEM and EDX analysis of the plated layer indicated the mixed distribution of Pd and Ag over the inner surface (Figure 1b). It has

Spectroscopic characterization of photoaccumulated radical anions: a litmus test to evaluate the efficiency of photoinduced electron transfer (PET) processes

• Maurizio Fagnoni,
• Stefano Protti,
• Davide Ravelli and
• Angelo Albini

Beilstein J. Org. Chem. 2013, 9, 800–808, doi:10.3762/bjoc.9.91

• intermediates. Keywords: aromatic nitriles; persistent radical anion; photochemical activation; photoinduced electron transfer (PET); photooxidant; reactive intermediates; Introduction Redox reactions between organic molecules have a limited scope because of the rarely matched redox potential. On the other

• electrochemical measurements were carried out by a BASi computer-controlled electrochemical analyzer. The potentials measured were then referred to SCE, applying the equation E (versus SCE) = E (versus Ag/AgCl; 3 M NaCl) − 35 mV. The redox potential of the excited state of compounds TCB [8][9], DCN [8][9], DCA [8

Modulating the activity of short arginine-tryptophan containing antibacterial peptides with N-terminal metallocenoyl groups

• H. Bauke Albada,
• Alina-Iulia Chiriac,
• Michaela Wenzel,
• Maya Penkova,
• Julia E. Bandow,
• Hans-Georg Sahl and
• Nils Metzler-Nolte

Beilstein J. Org. Chem. 2012, 8, 1753–1764, doi:10.3762/bjoc.8.200

• of the redox potential on the activity. We assume that the application of model systems will help us to determine the extent in which differences in chirality of the amino acids used to construct the peptides result in more or less favorable interactions. Conclusion We have shown that the replacement

Recent advances towards azobenzene-based light-driven real-time information-transmitting materials

• Jaume García-Amorós and
• Dolores Velasco

Beilstein J. Org. Chem. 2012, 8, 1003–1017, doi:10.3762/bjoc.8.113

• reversibly interconverted, with at least one of the reactions being induced by light excitation, between two forms with different absorption spectra [15]. These two forms differ also in many other physical properties, such as their redox potential, fluorescent intensity, acid/base strength, dielectric

Hybrid super electron donors – preparation and reactivity

• Jean Garnier,
• Douglas W. Thomson,
• Shengze Zhou,
• Phillip I. Jolly,
• Leonard E. A. Berlouis and
• John A. Murphy

Beilstein J. Org. Chem. 2012, 8, 994–1002, doi:10.3762/bjoc.8.112

• ) = −1.09 V, E2½ (DMF) = −0.97 V versus SCE]. The cyclic voltammetry studies on oxidised disalt 22 show two reversible one-electron transitions on its reduction to donor 9. The redox potential in the oxidation trace for the removal of the first electron from 9 shows that the molecule is not as strong a

Sexithiophenes as efficient luminescence quenchers of quantum dots

• Christopher R. Mason,
• Yang Li,
• Paul O’Brien,
• Neil J. Findlay and
• Peter J. Skabara

Beilstein J. Org. Chem. 2011, 7, 1722–1731, doi:10.3762/bjoc.7.202

• concentrations of ca. 10−3 M, together with n-Bu4NPF6 (0.1 M) as the supporting electrolyte. Under these conditions, the redox potential for the FcH/FcH+ couple was +0.48 V (CH2Cl2, versus Ag/AgCl). The photoluminescence properties of the oligothiophene and CdSe(ZnS) quantum dot blends were measured on a Spex

Coupled chemo(enzymatic) reactions in continuous flow

• Ruslan Yuryev,
• Simon Strompen and
• Andreas Liese

Beilstein J. Org. Chem. 2011, 7, 1449–1467, doi:10.3762/bjoc.7.169

• acetobutylicum strains, which convert glucose (7) to hydrogen (Scheme 20) [46]. The reactor was initially operated in batch mode until the redox potential went below −200 mV. Afterwards, the reactor was continuously fed with a solution of 7. During one week of continuous operation at 30 °C and retention time of

Photoinduced electron-transfer chemistry of the bielectrophoric N-phthaloyl derivatives of the amino acids tyrosine, histidine and tryptophan

• Axel G. Griesbeck,
• Jörg Neudörfl and
• Alan de Kiff

Beilstein J. Org. Chem. 2011, 7, 518–524, doi:10.3762/bjoc.7.60

• to −0.3 V for all cases: The redox potentials of the three amino acids tryptophan, histidine and tyrosine are reported to be 1.02 V [14], 1.17 V [15] and 0.93 V [16]. Due to this narrow redox potential window, similar electron-transfer properties can be expected. Among the amino acids investigated

Structure and reactivity in neutral organic electron donors derived from 4-dimethylaminopyridine

• Jean Garnier,
• Alan R. Kennedy,
• Leonard E. A. Berlouis,
• Andrew T. Turner and
• John A. Murphy

Beilstein J. Org. Chem. 2010, 6, No. 73, doi:10.3762/bjoc.6.73

• dication 16, and hence make formation of 16 more difficult. To determine the effect of bridge-length on redox potential, the analogous donors 14 and 15 were prepared in situ and converted to their respective oxidized salts 16 and 18, as shown in Figure 2, by reaction with iodine. Anion exchange to afford

Effect of transannular interaction on the redox- potentials in a series of bicyclic quinones

• Grigoriy Sereda,
• Jesse Van Heukelom,
• Miles Koppang,
• Sudha Ramreddy and
• Nicole Collins

Beilstein J. Org. Chem. 2006, 2, No. 26, doi:10.1186/1860-5397-2-26

• alternative conformations are marked with asterisk in the Table 1 and in the following text and Figures. The Figure 4 shows correlation between the first redox-potentials and calculated LUMO energies for compounds 1–5. The experimental redox-potential of the quinone 2 is 50 mV higher, than expected, based on

• this correlation and the calculated LUMO energy for its conformation A. This unexpectedly high redox-potential of 2 is consistent with the LUMO energy, calculated for the conformation B with two methyl groups, turned toward the quinone ring. This conformation is stabilized by weak H-bonds with the

• difference may fall below the threshold that would warrant sufficient concentrations of the conformation B to account for the experimental redox-potential of 2. Yamamura and co-authors [3] also noticed that the reduction potential of the quinone 2 was higher than expected from the electronic effects of the

The Elbs and Boyland- Sims peroxydisulfate oxidations

• E. J. Behrman

Beilstein J. Org. Chem. 2006, 2, No. 22, doi:10.1186/1860-5397-2-22

• - and p-benzoquinone where the difference in the redox potential is 0.07 V [11] corresponding to 3 kcal mol-1. It may also be relevant that quinones are subject to attack by the hydroxyl ion to form (eventually) humic acids and that o-quinones are more reactive than p-quinones. [12][13] An analogous