Solvothermal modification of magnesium phthalocyanine

Iodine Doping Implementation Effect on the Electrical Response in Metallophthalocyanines (M = Cu, Co, Zn), for Electronic and Photovoltaic Applications

We report the structural organization and its effect on the current response of the conducting domains in MPcs (M = Cu, Co, Zn) films, deposited by vacuum thermal evaporation and doped by the presence of iodine vapors. Structural and surface features of the doped metallophthalocyanines (MPcs) were studied by using IR spectroscopy, X-ray diffraction, atomic force microscope (AFM) and scanning electron microscope (SEM). DFT calculations were carried to study the interaction between iodine and MPcs molecules and establish the influence of iodine on the electronic behavior of these species and the changes on the frontier molecular orbitals. This interaction is thermodynamically favored, and the mechanism of electronic transit involving the iodine atoms providing electrons to the transfer. The I-MPc films have a mainly amorphous structure, some crystallinity in the MPcs α and β forms. A roughness between 18.41 and 99.02 nm and particle size between 1.35 and 15 μm. By evaluating the electrical behavior of the flexible PET/ITO/I-MPc/Ag devices, it was found that J-V curves under illuminated conditions show an increase of curves values upon the I-MPc, indicating that the flexible films are photosensible. Jsc between 1.59 × 10−5 and 2.41 × 10−7 A/cm2, conductivities between 6.17 × 10−8–2.54 × 10−7 Scm−1 and photosensibility values of up to 133%.

Magnesium Phthalocyanines and Tetrapyrazinoporphyrazines: The Influence of a Solvent and a Delivery System on a Dissociation of Central Metal in Acidic Media

Magnesium complexes of phthalocyanines (Pcs) and their aza-analogues have a great potential in medical applications or fluorescence detection. They are known to demetallate to metal-free ligands in acidic environments, however, detailed investigation of this process and its possible prevention is lacking. In this work, a conversion of lipophilic and water-soluble magnesium complexes of Pcs and tetrapyrazinoporphyrazines (TPyzPzs) to metal-free ligands was studied in relation to the acidity of the environment (organic solvent, water) including the investigation of the role of delivery systems (microemulsion or liposomes) in improvement in their acido-stability. The mechanism of the demetallation in organic solvents was based on an acidoprotolytic mechanism with the protonation of the azomethine nitrogen as the first step and a subsequent conversion to non-protonated metal-free ligands. In water, the mechanism seemed to be solvoprotolytic without any protonated intermediate. The water-soluble magnesium complexes were stable in a buffer with a physiological pH 7.4 while a time-dependent demetallation was observed in acidic pH. The demetallation was immediate at pH < 2 while the full conversion to metal-free ligand was done within 10 min and 45 min for TPyzPzs at pH 3 and pH 4, respectively. Incorporation of lipophilic magnesium complexes into microemulsion or liposomes substantially decreased the rate of the demetallation with the latter delivery system being much more efficient in the protection from the acidic environment. A comparison of two different macrocyclic cores revealed significantly higher kinetic inertness of magnesium TPyzPz complexes than their Pc analogues.

Water-Involved Hydrogen Bonds in Dimeric Supramolecular Structures of Magnesium and Zinc Phthalocyaninato Complexes

Two dimeric supramolecular structures {MgPc(H2O)·4-methylmorpholine}2-(1) and {ZnPc(H2O)·4-methylmorpholine}2-(2) formed from two molecules of magnesium and zinc aquaphthalocyanines in 4-methylmorpholine solution were revealed by single-crystal X-ray diffraction. Coordinated H2O molecules to the metal center of respective Mg or Zn phthalocyanines oriented face-to-face to form two hydrogen bonds, one of them connecting via O-H···N-azamethine atom to form a dimeric structure in the crystals with ring-to-ring distances of 3.412(3) Å in 1 and 3.403(5) Å in 2, whereas the second hydrogen bonds link the solvent 4-methylpholine molecules to form supramolecular dimeric {MgPc(H2O)·4-methylmorpholine}2-(1) and {ZnPc(H2O)·4-methylmorpholine}2-(2) structures. The interaction of the metal center of MgPc or ZnPc with O atom of the water molecule results its displacement of ∼0.5 Å from the N4-isonodole plane of the phthalocyaninate(2-) macrocycle that adopts a saucer-shape form. To better understand the interactions leading to the existence of the dimeric structures in the crystals, theoretical calculations of dimer stabilization energy composed of two monomers (MgPcH2O and ZnPcH2O), as well as three-dimensional molecular electrostatic potentials, have been performed using the density functional theoretical method. The calculated absorption spectra of both supramolecular monomers and dimers were compared with the experimental ones in 4-methylmorpholine solution. The water axial ligation of MgPc and ZnPc and the formation of the monomeric and dimeric supramolecular structures only slightly change the energy gap between highest occupied molecular orbital and lowest unoccupied molecular orbital levels that is compared with those of the parent MgPc and ZnPc pigments.