Driving Forces for the Mutual Conversions between Phenothiazines and Their Various Reaction Intermediates in Acetonitrile

Abstract

The thermodynamic driving forces (defined as the enthalpy changes or redox potentials in this work) of the 18 phenothiazines and their analogues, phenoxazine, N-methyl-dihydrophenazine, 9H-thioxanthene, 9H-xanthene and 9,10-dihydro- N-methylacridine, to release hydride, hydrogen atom, proton, and electron in acetonitrile, the thermodynamic driving forces of the radical cations of the phenothiazines and the analogues to release hydrogen atom, proton, and electron in acetonitrile, and the thermodynamic driving forces of the cations of the phenothiazines with two positive charges and their analogues to release proton in acetonitrile were estimated by using experimental methods. The effect of the remote substituents on the 11 determined thermodynamic driving forces were examined according to Brown's substituent parameters; the results show that the values of the 11 thermodynamic driving forces all are linearly dependent on the sum of Brown substituent parameters (sigma +) with very good correlation coefficients, which indicates that for any one- or multisubstituted at para- and/or meta-position phenothiazines and their various reaction intermediates, the 11 thermodynamic driving forces all can be easily and safely estimated from the corresponding Brown substituent parameters (sigma +). The relative effective charges on the center nitrogen atom in phenothiazines and their various reaction intermediates were estimated from the related Hammett-type linear free-energy relationships, which can be used to efficiently measure the electrophilicity, nucleophilicity, and dimerizing ability of the corresponding reaction intermediates of phenothiazines and their analogues. All the information disclosed in this work could not only supply a gap of the chemical thermodynamics on the mutual conversions between phenothiazines and their various reaction intermediates in solution but also strongly promote the fast development of the chemistry and application of phenothiazines and their analogues.

Pyridomethene–BF2 complex/phenothiazine hybrid sensitizer with high molar extinction coefficient for efficient, sensitized solar cells

“…7 and S3). [51][52][53] The second oxidation of dyes K1-K8 occurred upon the removal of an electron from the pyridomethene-BF 2 complex and it is consistent with the oxidation potential of P3. 8.…”

Phenoxazine Dyes for Dye‐Sensitized Solar Cells: Relationship Between Molecular Structure and Electron Lifetime

“…[24] This is because the PTZ unit displayed a stronger electron-donating ability than the TPA unit (0.848 and 1.04 V vs. the normal hydrogen electrode (NHE), respectively). [28] Phenoxazine (POZ) shows similar structural and electrochemical properties to PTZ (0.880 V vs. NHE), [28] which implies that POZ could also be incorporated as a dye sensitizer. Despite this, most of the previous work has focused on PTZ as the donor.…”

Phenothiazine‐Capped Gold Nanoparticles: Photochemically Assisted Synthesis and Application in Electrosensing of Phosphate Ions

“…Few amines and amino acids have the capability to reduce Au (III) as well as the ability to stabilize the nanoparticles through weak covalent and weak electrostatic interaction between gold and nitrogen atoms. [8,24] In the present work, HAuCl 4 was reduced photochemically by PTZH. [3] Although PTZH and its products do not have long chain structures, they can stabilize AuNPs through coordination with the nitrogen and sulfur site present within their structures.…”