Electron spin resonance study of the copper(II) and cobalt(II) chelates of 2,3; 7,8; 12,13; 17,18-tetrakis-(9,10-dihydroanthracene-9,10-diyl)porphyrazine

Oliver, Stuart W.; Smith, Thomas D.; Hanson, Graeme R.; Lahy, Neil; Pilbrow, John R.; Sinclair, Geoffrey R.

doi:10.1039/f19888401475

Cited by 7 publications

(2 citation statements)

References 1 publication

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“…signal in (3) is indicative of the formation of the Mn 2þ complex, since the Mn 3þ complexes are e.s.r. silent [53,54]. The ground (3) is not well resolved.…”

Section: Electrocatalysis Studiesmentioning

confidence: 91%

Synthesis of new octakis(benzylthio)tetraazaporphyrin complexes with bivalent transition metal ions and an investigation of their spectral, redox and catalytic properties

Prasad

Kumar

2004

Transition Metal Chemistry

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Transition metals in the þ2 oxidation state form complexes with octakis(benzylthio)tetraazaporphyrin [M{TAP(SBn) 8 }] (M ¼ Mn 2þ , Co 2þ , Ni 2þ , Cu 2þ , Zn 2þ and 2H þ ; Bn ¼ ACH 2 Ph; TAP ¼ tetraazaporphyrin) and were prepared via demetallation of the template-synthesized complex [Mg{TAP(SBn) 8 }] in ClCH 2 COOH, followed by insertion of the metal ions in a PhCl-DMF mixture. All compounds were characterized by u.v-vis, 1 H-n.m.r., e.s.r. and mass spectra, microanalyses and magnetic susceptibility data. PM3 geometry optimization showed near coplanar arrangement of five phenyl rings vis-a`-vis the TAP ring plane, while the remaining three phenyl rings lie bent over it. The Mn 2þ , Co 2þ and Cu 2þ complexes exhibited reversible one electron oxidation waves, that were observed at E 1/2 À0.33, À0.29 and 0.58 V versus Ag/AgCl respectively. They all exhibited an irreversible reduction wave at E p À1.1 V versus Ag/AgCl followed by appearance of an irreversible oxidation wave at E p 1.1-1.2 V versus Ag/AgCl. This has been interpreted in terms of reductive dissociation, leading to removal of the benzyl substituents, and subsequent oxidation of thiolate products. The Mn 2þ , Co 2þ and Cu 2þ complexes exhibited metal ion-based e.s.r. signals. The [Co{TAP(SBn) 8 }] complex in a homogeneous DMF solution was found to catalyze electroreduction/oxidation of nitrite ions. In the presence of a 1/5 molar quantity of the complex [Co{TAP(SBn) 8 }], the nitrite reduction peak was observed to be shifted by 0.1 V towards the positive potential side and the peak current rose by a factor of 1.33. Similarly a sharp rise in the anodic current, corresponding to oxidation of nitrite ions, was observed in the presence of the complex.

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“…signal in (3) is indicative of the formation of the Mn 2þ complex, since the Mn 3þ complexes are e.s.r. silent [53,54]. The ground (3) is not well resolved.…”

Section: Electrocatalysis Studiesmentioning

confidence: 91%

Synthesis of new octakis(benzylthio)tetraazaporphyrin complexes with bivalent transition metal ions and an investigation of their spectral, redox and catalytic properties

Prasad

Kumar

2004

Transition Metal Chemistry

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“…There is additional splitting on the lines to high field from superhyperfine coupling of all four nitrogen ( 14 N, I = 1, 99.7% abundant) donor atoms of the Mabiq ligand. Such a profile is very familiar in macrocyclic CuN 4 complexes. , The spectrum was simulated, yielding spin-Hamiltonian parameters: g iso = 2.0782; A Cu = 87 × 10 –4 cm –1 ; A N = 14.5 × 10 –4 cm –1 (Figure ). The addition of THF to this sample of 1 afforded a homogeneous frozen glass at 140 K. The spectrum is quintessentially that of a Cu II species with an unpaired electron in the d x 2 – y 2 orbital ( 2 B 2 ground state) with anisotropic spin-Hamiltonian parameters for Cu: g = (2.037, 2.040, 2.153); A Cu = (25, 22, 218) × 10 –4 cm –1 .…”

Section: Solution-state Characterizationmentioning

confidence: 99%

Structural Characterization and Photochemical Properties of Mono- and Bimetallic Cu-Mabiq Complexes

et al. 2018

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We present a series of monometallic ([Cu(Mabiq)OTf] (1) and [Cu(Mabiq)] (2)) and bimetallic copper-Mabiq complexes ([Cu(Mabiq)(PPh)(OTf)] (3) and [Cu(Mabiq)(PPh)]PF (4)). The latter compounds contain an additional Cu center that binds in a tetrahedral fashion to the external bipyrimidine nitrogens of the macrocyclic ligand. Compounds 3 and 4 represent the first examples of bimetallic transition metal Mabiq complexes, stable both in solution and in the solid state. The structural and electronic properties of compounds 1-4 were analyzed by means of X-ray crystallography, cyclic voltammetry, and spectroscopic methods. One-electron reduced 2 and 4 consist of a Cu ion coordinated by a Mabiq ligand radical, [Cu(Mabiq)]. Thus, both bimetallic compounds are mixed-valent with respect to the copper oxidation states. Complexes 2 and 4 can be generated photochemically, upon irradiation of 1 or 3 with visible light in the presence of a sacrificial electron donor.

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Influence of solvents and substituents on the EPR spectra and stability of copper porphyrazinates with an axial ligand

et al. 1990

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Electron spin resonance study of the copper(II) and cobalt(II) chelates of 2,3; 7,8; 12,13; 17,18-tetrakis-(9,10-dihydroanthracene-9,10-diyl)porphyrazine

Cited by 7 publications

References 1 publication

Synthesis of new octakis(benzylthio)tetraazaporphyrin complexes with bivalent transition metal ions and an investigation of their spectral, redox and catalytic properties

Synthesis of new octakis(benzylthio)tetraazaporphyrin complexes with bivalent transition metal ions and an investigation of their spectral, redox and catalytic properties

Structural Characterization and Photochemical Properties of Mono- and Bimetallic Cu-Mabiq Complexes

Influence of solvents and substituents on the EPR spectra and stability of copper porphyrazinates with an axial ligand

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