Synthesis and Electronic Properties of 3‐Acceptor‐Substituted and 3,7‐Bisacceptor‐Substituted Phenothiazines

Abstract

Keywords: Catalysis / Cyclic voltammetry / Fluorescence / Heterocycles / Substituent effects 3-Acceptor-substituted and 3,7-bisacceptor-substituted phenothiazines can be synthesized in moderate to excellent yields through Suzuki cross-coupling reactions between phenothiazin-3-yl pinacolyl boronates or phenothiazin-3,7-diyl bis(pinacolyl boronates) and electron-deficient (hetero)aryl halides. The electronic properties of (hetero)aryl-substituted N-methyl phenothiazines (UV/Vis absorption, fluorescence, redox potentials) can be correlated with the computed energies of the frontier molecular orbitals. Nitro-substituted de-

Harvesting solar energy using conjugated metallopolyyne donors containing electron-rich phenothiazine–oligothiophene moieties

“…The relevant data are collected in Table 2. From the onset values of oxidation potential (E onset, ox ) and reduction potential (E onset, red ), the HOMO and LUMO levels of the polymers were calculated according to the following equations E HOMO = À(E onset, ox + 4.72) eV and E LUMO = À(E onset, red + 4.72) eV (where the unit of potential is V versus Ag/AgCl) [ the oxidation (p-doping) process of the polymer [66,67,70]. Each of P1ÀP2 shows a quasi-reversible phenothiazinyl oxidation at 0.84 and 0.79 V, respectively, and the oxidation potential is reduced with increasing thienyl chain length m, consistent with the phenomenon that delocalization of the generated phenothiazine radical cations is apparently more favored and stabilized by increased conjugation length [98][99][100][101][102][103][104][105] For P2, two additional anodic waves due to the bithienyl cores also appeared at the more positive potentials peaking at ca.…”

“…Following this line, we report here the synthesis, characterization and photovoltaic behavior of some bandgap-tunable metallopolyynes containing the bis(oligothienyl)-phenothiazine spacer. Phenothiazine (PTZ) belongs to an important class of tricyclic nitrogen-sulfur heterocycles [56], with a broad spectrum of pharmacological activity [57][58][59][60][61][62][63] Phenothiazine has low and highly reversible first oxidation potentials [64][65][66][67] with pronounced propensities to form stable radical cations. Also, phenothiazine and its derivatives serve as good intramolecular reductive quenchers because they show a facile one electron oxidation, and the PTZ radical cation (PTZ Å+ ) is known to have a strong absorption in the visible region [68][69] This makes the identification of the charge-separated intermediate formed upon electron transfer from PTZ to the 3 MLCT excited state of the chromophore unambiguous [70][71][72][73].…”

Synthesis and structure of new 3,7,10-substituted-phenothiazine derivatives

“…The yields varied in this case from fair to good. In order to elaborate procedures for the synthesis of other intermediates we transformed compound 6 into its diboronic ester 14 (by a procedure taken from the literature [19]) and then by a palladium catalyzed Suzuki coupling reaction [20][21][22][23][24][25] of macrocycles, which after similar modifications with those shown for 2-4 could be transformed into the mercapto derivatives and then deposited on gold 1.1.1 surface.…”

Macrocycles embedding phenothiazine or similar nitrogen and/or sulphur containing heterocycles

“…Due to these interesting properties phenothiazine derivatives are widely used for the obtaining of new materials such as: electroactive polymers [28][29][30], dyads and triads [31][32][33][34], cruciform fluorophores [35], molecular wires [36] or ligands for surface modifications [37][38][39]. Innovative redox-active materials were obtained with compounds showing two or more (up to seven) phenothiazines directly connected to each other [40][41][42][43] or via ethynyl or aryl units [44][45][46][47].…”