A series of metal complexes of tetrakis-2,3-[5,6-di(2-pyridyl)pyrazino]porphyrazine, [Py8TPyzPzH2], having the general formula [Py8TPyzPzM]âxH2O (M ) MgII(H2O), MnII, CoII, CuII, ZnII; x ) 3-8) were synthesized by reaction of the free-base macrocycle with the appropriate metal acetate in pyridine or dimethyl sulfoxide under mild conditions. Clathrated water and retained pyridine molecules for the MnII and CoII species are easily eliminated by heating under vacuum, the water molecules being recovered by exposure of the unsolvated macrocycles to air. Magnetic susceptibility measurements and EPR spectra of the materials in the solid state provide basic information on the spin state of the CuII, CoII, and MnII species. Colloidal solutions caused by molecular aggregation are formed in nondonor solvents (CH2Cl2, CHCl3), a moderately basic solvent (pyridine), and an acidic solvent (CH3COOH), with the extent of aggregation depending on the specific solvent and the central metal ion. UV-vis spectral monitoring of the solutions after preparation indicates that disaggregation systematically occurs as a function of time leading ultimately to the formation of clear solutions containing the monomeric form of the porphyrazine. Cyclic voltammetry and thin-layer spectroelectrochemistry show that each compound with an electroinactive metal ion undergoes four reversible one-electron reductions, leading to formation of the negatively charged species [Py8TPyzPzM]n- (n ) 1 - 4). The stepwise uptake of four electrons is consistent with a ring-centered reduction, but in the case of the cobalt complex a metal-centered (CoII f CoI) reduction occurs in the first process and only three additional reductions are observed. No oxidations are observed in pyridine or CH2Cl2 containing 0.1 M tetrabuthylammonium perchlorate (TBAP). The nonlinear optical properties (NLO) of the species [Py8TPyzPzM] (M ) 2HI, CuII, ZnII, MgII(H2O)) have also been examined with nanosecond pulses at 532 nm in dimethyl sulfoxide solution. Reverse saturable absorption is shown by all of the [Py8TPyzPzM] species, which exhibit distinct behavior depending on the nature of M and extent of aggregation.

Tetra-2,3-pyrazinoporphyrazines with Externally Appended Pyridine Rings. 2. Metal Complexes of Tetrakis-2,3-[5,6-di(2-piridyl)pyrazino]porphyrazine: Linear and Nonlinear Optical Properties and Electrochemical Behavior / Donzello, Maria Pia; Zoungping, Ou; Dini, Danilo; Moreno, Meneghetti; Ercolani, Claudio; Karl M., Kadish. - In: INORGANIC CHEMISTRY. - ISSN 0020-1669. - STAMPA. - 43:(2004), pp. 8637-8648. [10.1021/ic0489084]

Tetra-2,3-pyrazinoporphyrazines with Externally Appended Pyridine Rings. 2. Metal Complexes of Tetrakis-2,3-[5,6-di(2-piridyl)pyrazino]porphyrazine: Linear and Nonlinear Optical Properties and Electrochemical Behavior

DONZELLO, Maria Pia;DINI, DANILO;ERCOLANI, Claudio;
2004

Abstract

A series of metal complexes of tetrakis-2,3-[5,6-di(2-pyridyl)pyrazino]porphyrazine, [Py8TPyzPzH2], having the general formula [Py8TPyzPzM]âxH2O (M ) MgII(H2O), MnII, CoII, CuII, ZnII; x ) 3-8) were synthesized by reaction of the free-base macrocycle with the appropriate metal acetate in pyridine or dimethyl sulfoxide under mild conditions. Clathrated water and retained pyridine molecules for the MnII and CoII species are easily eliminated by heating under vacuum, the water molecules being recovered by exposure of the unsolvated macrocycles to air. Magnetic susceptibility measurements and EPR spectra of the materials in the solid state provide basic information on the spin state of the CuII, CoII, and MnII species. Colloidal solutions caused by molecular aggregation are formed in nondonor solvents (CH2Cl2, CHCl3), a moderately basic solvent (pyridine), and an acidic solvent (CH3COOH), with the extent of aggregation depending on the specific solvent and the central metal ion. UV-vis spectral monitoring of the solutions after preparation indicates that disaggregation systematically occurs as a function of time leading ultimately to the formation of clear solutions containing the monomeric form of the porphyrazine. Cyclic voltammetry and thin-layer spectroelectrochemistry show that each compound with an electroinactive metal ion undergoes four reversible one-electron reductions, leading to formation of the negatively charged species [Py8TPyzPzM]n- (n ) 1 - 4). The stepwise uptake of four electrons is consistent with a ring-centered reduction, but in the case of the cobalt complex a metal-centered (CoII f CoI) reduction occurs in the first process and only three additional reductions are observed. No oxidations are observed in pyridine or CH2Cl2 containing 0.1 M tetrabuthylammonium perchlorate (TBAP). The nonlinear optical properties (NLO) of the species [Py8TPyzPzM] (M ) 2HI, CuII, ZnII, MgII(H2O)) have also been examined with nanosecond pulses at 532 nm in dimethyl sulfoxide solution. Reverse saturable absorption is shown by all of the [Py8TPyzPzM] species, which exhibit distinct behavior depending on the nature of M and extent of aggregation.
2004
01 Pubblicazione su rivista::01a Articolo in rivista
Tetra-2,3-pyrazinoporphyrazines with Externally Appended Pyridine Rings. 2. Metal Complexes of Tetrakis-2,3-[5,6-di(2-piridyl)pyrazino]porphyrazine: Linear and Nonlinear Optical Properties and Electrochemical Behavior / Donzello, Maria Pia; Zoungping, Ou; Dini, Danilo; Moreno, Meneghetti; Ercolani, Claudio; Karl M., Kadish. - In: INORGANIC CHEMISTRY. - ISSN 0020-1669. - STAMPA. - 43:(2004), pp. 8637-8648. [10.1021/ic0489084]
File allegati a questo prodotto
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/240389
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? 1
  • Scopus 85
  • ???jsp.display-item.citation.isi??? 84
social impact