Manganese Phthalocyanine Coordination Chemistry: Recent Results and Present Status

Abstract

<jats:p> A number of substituted manganese phthalocyanines ( PcMn ), which are easily soluble in organic solvents, have been synthesized with good yields (up to 76%) and high purity. PcMn with manganese +2 oxidation state without axial ligands was obtained for the first time and thoroughly characterized. It was shown that PcMn forms, PcMn <jats:sup>III</jats:sup> X , PcMn <jats:sup>II</jats:sup> or [ LPcMn <jats:sup>III</jats:sup>]<jats:sub>2</jats:sub> O , depending on substituents nature, can be stable in usual conditions. It was found that some PcMn <jats:sup>II</jats:sup> derivatives can be oxidized by water to PcMn <jats:sup>III</jats:sup> OH . The stages of substituted PcMn electrochemical reduction and oxidation have been studied and the correlation of redox potentials with electronic properties of substituents has been established. For the first time, the idea has been proposed and confirmed that PcMn <jats:sup>II</jats:sup>, when treated by organic bases in solution forms an equilibrium mixture of three electronic isomers — Pc <jats:sup>+·</jats:sup> Mn <jats:sup>I</jats:sup>, PcMn <jats:sup>II</jats:sup> and Pc <jats:sup>−·</jats:sup> Mn <jats:sup>III</jats:sup>. A new scheme of PcMn photoreactions has been proposed and the possibility of using PcMn as a model of a photosystem component has been discussed. All the data are summarized in the complete scheme of photo and dark transformations between valence and coordination PcMn derivatives in solution. </jats:p>

Tuning the visible colour of octahedral manganese( iii ) phthalocyanines via axial ligand exchange

“…Upon the addition of water, and vigorous stirring of the biphasic mixture, this peak at 620 nm grew in intensity to represent the dominant species in solution, which was previously reported to be (PcMnPy) 2 O . 26,32 Thus, in the presence of water and a sufficiently strong base, the μ-oxo dimer is generated. As a result, if these species are not desired, reactions with N-bound strong donors must be kept anhydrous in order to retard their formation.…”

Tuning the visible colour of octahedral manganese( iii ) phthalocyanines via axial ligand exchange

“…Upon the addition of water, and vigorous stirring of the biphasic mixture, this peak at 620 nm grew in intensity to represent the dominant species in solution, which was previously reported to be (PcMnPy) 2 O . 26,32 Thus, in the presence of water and a sufficiently strong base, the μ-oxo dimer is generated. As a result, if these species are not desired, reactions with N-bound strong donors must be kept anhydrous in order to retard their formation.…”

Metallophthalocyanines as Catalysts in Aerobic Oxidation

“…MnPc and its substituted derivatives [25] can contain either Mn(II) and Mn(III); the very complex redox equilibria between the two oxidation states are highly sensitive to the presence of even traces of water. Additionally, reactions of Mn(II) derivatives with dioxygen (O 2 ) are very sensitive to the experimental conditions.…”

“…Figure25. Schematic representation of the hybrid catalyst Fe(II)Pc(NO 2 ) 3 S@GO obtained from the iron phthalocyanine FePc(NO 2 ) 4 and graphene oxide (GO) nanosheets (adapted from[74]).…”

Electropolymerization and Electrochemical Pesticide Sensor Application of Metallophthalocyanines Bearing Polymerizable Morpholin Groups

“…It is well documented that Mn(III) center of MnClPc can axially coordinate with different electron donating groups. 54,55 Axial ligand could be easily changed with different groups during electron transfer reactions. Therefore, it can be easily proposed that the voltammetric responses of GCE/MnClPc electrode during titration with diazinon was resulted from the coordination of diazinon to Mn(III) center of MnClPc with phosphorus group of diazinon.…”

Tuning the visible colour of octahedral manganese( iii ) phthalocyanines via axial ligand exchange

“…Upon the addition of water, and vigorous stirring of the biphasic mixture, this peak at 620 nm grew in intensity to represent the dominant species in solution, which was previously reported to be (PcMnPy) 2 O . 26,32 Thus, in the presence of water and a sufficiently strong base, the μ-oxo dimer is generated. As a result, if these species are not desired, reactions with N-bound strong donors must be kept anhydrous in order to retard their formation.…”

Metallophthalocyanines as Catalysts in Aerobic Oxidation

“…MnPc and its substituted derivatives [25] can contain either Mn(II) and Mn(III); the very complex redox equilibria between the two oxidation states are highly sensitive to the presence of even traces of water. Additionally, reactions of Mn(II) derivatives with dioxygen (O 2 ) are very sensitive to the experimental conditions.…”

“…Figure25. Schematic representation of the hybrid catalyst Fe(II)Pc(NO 2 ) 3 S@GO obtained from the iron phthalocyanine FePc(NO 2 ) 4 and graphene oxide (GO) nanosheets (adapted from[74]).…”

Electropolymerization and Electrochemical Pesticide Sensor Application of Metallophthalocyanines Bearing Polymerizable Morpholin Groups

“…It is well documented that Mn(III) center of MnClPc can axially coordinate with different electron donating groups. 54,55 Axial ligand could be easily changed with different groups during electron transfer reactions. Therefore, it can be easily proposed that the voltammetric responses of GCE/MnClPc electrode during titration with diazinon was resulted from the coordination of diazinon to Mn(III) center of MnClPc with phosphorus group of diazinon.…”

Tuning the visible colour of octahedral manganese( iii ) phthalocyanines via axial ligand exchange

“…Upon the addition of water, and vigorous stirring of the biphasic mixture, this peak at 620 nm grew in intensity to represent the dominant species in solution, which was previously reported to be (PcMnPy) 2 O . 26,32 Thus, in the presence of water and a sufficiently strong base, the μ-oxo dimer is generated. As a result, if these species are not desired, reactions with N-bound strong donors must be kept anhydrous in order to retard their formation.…”

Metallophthalocyanines as Catalysts in Aerobic Oxidation

“…MnPc and its substituted derivatives [25] can contain either Mn(II) and Mn(III); the very complex redox equilibria between the two oxidation states are highly sensitive to the presence of even traces of water. Additionally, reactions of Mn(II) derivatives with dioxygen (O 2 ) are very sensitive to the experimental conditions.…”

“…Figure25. Schematic representation of the hybrid catalyst Fe(II)Pc(NO 2 ) 3 S@GO obtained from the iron phthalocyanine FePc(NO 2 ) 4 and graphene oxide (GO) nanosheets (adapted from[74]).…”

Electropolymerization and Electrochemical Pesticide Sensor Application of Metallophthalocyanines Bearing Polymerizable Morpholin Groups

“…It is well documented that Mn(III) center of MnClPc can axially coordinate with different electron donating groups. 54,55 Axial ligand could be easily changed with different groups during electron transfer reactions. Therefore, it can be easily proposed that the voltammetric responses of GCE/MnClPc electrode during titration with diazinon was resulted from the coordination of diazinon to Mn(III) center of MnClPc with phosphorus group of diazinon.…”