New core-pyrene π structure organophotocatalysts usable as highly efficient photoinitiators

• Sofia Telitel,
• Frédéric Dumur,
• Thomas Faury,
• Bernadette Graff,
• Mohamad-Ali Tehfe,
• Didier Gigmes,
• Jean-Pierre Fouassier and
• Jacques Lalevée

Beilstein J. Org. Chem. 2013, 9, 877–890, doi:10.3762/bjoc.9.101

• saturated calomel electrode-SCE). Ferrocene was used as a standard and the potentials were determined from half-peak potentials. The free energy change ΔGet for an electron-transfer reaction is calculated from the classical Rehm–Weller equation (Equation 1) [60] where Eox, Ered, ES and C are the oxidation

• potential of the donor, the reduction potential of the acceptor, the excited state energy and the coulombic term for the initially formed ion pair, respectively. C is neglected as usually done in polar solvents. Fluorescence experiments The fluorescence properties of the different Co_Pys were studied by

Synthesis, photophysical and electrochemical characterization of terpyridine-functionalized dendritic oligothiophenes and their Ru(II) complexes

• Amaresh Mishra,
• Elena Mena-Osteritz and
• Peter Bäuerle

Beilstein J. Org. Chem. 2013, 9, 866–876, doi:10.3762/bjoc.9.100

• a more positive value (ΔE ≈ 40 mV) compared to the terthiophene dendron [42]. The oxidation potential of the second-generation ligand 9 was also positively shifted by 30–60 mV compared to the corresponding dendron. This positive potential shift is the consequence of a stabilization of the tpy ligand

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

• from 2,6,9,10-tetracyanoanthracene with amines [38]). As for the donors, these were chosen on the basis of their oxidation potential (see Table 1 and Figure 1), to allow for an overall exergonic electron transfer from the donor to the excited acceptor in all of the cases considered below [39]. The

• oxidation potential of the ground-state donors examined in this work. aValue measured in the present work (see Experimental). UV-monitoring of: (a) a 2 × 10−4 M solution of TCB in the presence of Bu4Sn (10−2 M) and (b) a 1.5 × 10−4 M solution of TCB in the presence of OXA (5 × 10−2 M) in freeze–pump–thaw

Efficient electroorganic synthesis of 2,3,6,7,10,11-hexahydroxytriphenylene derivatives

• Carolin Regenbrecht and
• Siegfried R. Waldvogel

Beilstein J. Org. Chem. 2012, 8, 1721–1724, doi:10.3762/bjoc.8.196

• trimerization protocol [14][15][16]. Usually, yields are in a moderate range (≤35%) [15] when the electrolysis is performed on platinum or graphite anodes in anhydrous and non-nucleophilic electrolytes [14]. Poor yields are caused by the low oxidation potential of the products and the preference for over

The effect of the formyl group position upon asymmetric isomeric diarylethenes bearing a naphthalene moiety

• Renjie Wang,
• Shouzhi Pu,
• Gang Liu and
• Shiqiang Cui

Beilstein J. Org. Chem. 2012, 8, 1018–1026, doi:10.3762/bjoc.8.114

• molecular orbital (LUMO) energy level, the band gap Eg (Eg = LUMO–HOMO) of 1o and 1c can be determined to be +2.50 and +2.67 eV. Similarly, the oxidation potential of 2o and 3o is initiated at +1.76 and +1.83 V, and that of 2c and 3c is initiated at +1.74 and +1.79 V. The results indicate that the oxidation

Thiophene-based donor–acceptor co-oligomers by copper-catalyzed 1,3-dipolar cycloaddition

• Stefanie Potratz,
• Amaresh Mishra and
• Peter Bäuerle

Beilstein J. Org. Chem. 2012, 8, 683–692, doi:10.3762/bjoc.8.76

• the 2-vinylthiophene subunit at 1.15 V and 1.13 V vs Fc/Fc+, respectively. For co-oligomer 11, the oxidation potential was significantly higher (1.23 V) and indicates formation of a radical cation localized on the thiophene subunits. In the negative regime, no reduction wave for the 1,2,3-triazole

A ferrocene redox-active triazolium macrocycle that binds and senses chloride

• Nicholas G. White and
• Paul D. Beer

Beilstein J. Org. Chem. 2012, 8, 246–252, doi:10.3762/bjoc.8.25

• caused a cathodic shift of the oxidation potential of 25 mV and a loss of reversibility, which may be indicative of an EC mechanism [14] (Figure 4). Further addition of TBA·Cl led to increasing cathodic perturbations of the Epa oxidation wave of up to 40 mV after five equiv. As noted with other ferrocene

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

• . The corresponding reduction process is also shifted from +0.56 V to +0.41 V. The second oxidation potential for 1b experiences a shift to lower values (1.04 V compared to 0.89 V), but the reversibility is diminished somewhat; ΔE2a–c (mV) 2b, 170 mV; 1b, 270 mV. The decrease in oxidation potentials of

Conjugated polymers containing diketopyrrolopyrrole units in the main chain

• Bernd Tieke,
• A. Raman Rabindranath,
• Kai Zhang and
• Yu Zhu

Beilstein J. Org. Chem. 2010, 6, 830–845, doi:10.3762/bjoc.6.92

• give rise to a lower oxidation potential of the polymer. Relevant polymers P-16 - P-20 (Table 3) were synthesized using Pd-catalyzed aryl amination reactions as reported by Hartwig [38][39], Buchwald [40][41][42], and Kanbara [43][44][45][46][47]. As shown in Scheme 2, DPP monomers such as M-1 were

• , respectively. The absorption and emission colours are shown in Figure 4. Stille coupling of M-1 and 2-(tributylstannyl)-3,4-ethylenedioxythiophene gave the corresponding bis(thienyl)-substituted monomer [49]. Due to presence of the EDOT units, the monomer exhibited a rather low oxidation potential and could be

• reversible electrochromic properties whereas the polymer with EDOT-phenyl groups in the 2- and 5- positions (structure II in Table 4) is non-conjugated, possesses a high oxidation potential and is not electrochromic (Figure 5). Our activities have stimulated several other groups to synthesize diphenylDPP

Synthetic incorporation of Nile Blue into DNA using 2′-deoxyriboside substitutes: Representative comparison of (R)- and (S)-aminopropanediol as an acyclic linker

• Daniel Lachmann,
• Sina Berndl,
• Otto S. Wolfbeis and
• Hans-Achim Wagenknecht

Beilstein J. Org. Chem. 2010, 6, No. 13, doi:10.3762/bjoc.6.13

• Ered −0.3 V (vs. NHE), the excited state potential is estimated to be E*red = 2.2 eV [17]. Hence, a photooxidation of guanine is highly favorable because the oxidation potential of guanine is only ~1.3–1.4 V [44]. Hence sequence-dependent fluorescence quenching of the Nile Blue dye in DNA was expected

Prediction of reduction potentials from calculated electron affinities for metal-salen compounds

• Sarah B. Bateni,
• Kellie R. England,
• Anthony T. Galatti,
• Handeep Kaur,
• Victor A. Mendiola,
• Alexander R. Mitchell,
• Michael H. Vu,
• Benjamin F. Gherman and
• James A. Miranda

Beilstein J. Org. Chem. 2009, 5, No. 82, doi:10.3762/bjoc.5.82

• whether a potential substituted triphenylamine was likely to have a high enough oxidation potential to be useful as an electrocatalyst for a difficultly oxidized organic substrate before embarking upon a proposed synthesis of the substituted triphenylamine. By using Fry’s method of calculating EAs to

Synthesis and redox behavior of new ferrocene- π-extended- dithiafulvalenes: An approach for anticipated organic conductors

• Abdelwareth A. O. Sarhan,
• Omar F. Mohammed and
• Taeko Izumi

Beilstein J. Org. Chem. 2009, 5, No. 6, doi:10.3762/bjoc.5.6

• cyclic voltammetry at ambient temperature on a Pt working electrode, using TBAP as the supporting electrolyte. The CV exhibited good donor properties, showing a one-electron quasireversible oxidation potential. The oxidation potential values, and to a larger extent the reduction potential values, are

• strongly influenced by the scan rate. Increasing the scan rate from 20 to 600 mV s−1 leads to an increase of the oxidation potential values. The Fc-DTF derivatives 9 and 12 were prepared as side products during the synthesis of the targeted compounds as 1,1′-bis(1,3-DTF)Fc’s 8, 10 and 11 in variable yields

Generation of pyridyl coordinated organosilicon cation pool by oxidative Si-Si bond dissociation

• Toshiki Nokami,
• Ryoji Soma,
• Yoshimasa Yamamoto,
• Toshiyuki Kamei,
• Kenichiro Itami and
• Jun-ichi Yoshida

Beilstein J. Org. Chem. 2007, 3, No. 7, doi:10.1186/1860-5397-3-7

• was found that the introduction of a coordinating group such as a pyridyl group decreased the oxidation potential of tetraalkylstannanes, although there is no indication of the coordination in the neutral molecule. Dynamic intramolecular coordination to tin seems to facilitate electron transfer [22

• pyridyl group as a donor ligand. First, we prepared disilanes having pyridyl groups in appropriate positions and measured their oxidation potentials [24][25]. The oxidation potential of 2-pyridylethyl substituted disilane 1b was slightly less positive than hexamethyldisilane 1a. On the other hand, the

• oxidation potential of 2-pyridylphenyl substituted disilane 1d was much less positive than the corresponding disilane 1c having phenyl groups (Figure 1). 29Si NMR chemical shifts of 1b and 1d were similar to those of 1a and 1c, indicating that no coordination of the pyridyl groups on silicon existed in the

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

• correlation illustrates that similarly to the first redox-potentials, prediction of second redox-potentials should be performed with consideration of the conformation with the highest oxidation potential, which is conformation B for quinones 2 and 3. The correlation on Figure 5 and Figure 6 demonstrate that

• formal redox-potential Eo'1, second reduction potential Epr2, second oxidation potential Epox2 and second redox-potential Eo'2) for compounds 1–5 are presented in Table 1. The computed parameters for compounds 1–5 and for their reduced species 1·−–5·− are presented in Table 2. Bicyclic quinones explored