Electrochemistry of Aluminum Phthalocyanine:  Solvent and Anion Effects on UV−Visible Spectra and Reduction Mechanisms

Abstract

The electrochemistry and UV-vis spectral properties of neutral and electroreduced Al(III) phthalocyanine, (Pc)AlCl, were characterized in four different nonaqueous solvents (THF, DMSO, DMF, and pyridine) containing tetra-n-butylammonium perchlorate, as well as in THF containing 0.4 M TBAP and the more strongly coordinating Cl-, F-, OH-, or CN- anions added to solution in the form of a tetra-n-butylammonium salt. The initial phthalocyanine added to solution is represented as (Pc)AlCl, but the actual electroactive form of the compound varied as a function of both the solvent and type or number of bound anionic axial ligands. An uncharged (Pc)AlCl(THF) or (Pc)Al(CN)(THF) complex is present in THF solutions containing 0.4 M TBAP and excess Cl- or CN-, while transient mu-oxo dimers are spectroscopically observed upon addition of OH- or F- to (Pc)AlCl(THF) in THF followed by the ultimate formation of stable six-coordinate anionic species represented as [(Pc)Al(OH)2]- or [(Pc)AlF2]-. Each phthalocyanine undergoes three reversible one-electron additions at the conjugated Pc macrocycle within the negative potential limit of the solvent, and the UV-vis spectral changes obtained during the first two reductions were recorded in a thin-layer cell to evaluate the prevailing electron-transfer mechanisms.

Optical Spectra of Phthalocyanines and Related Compounds

“…When two molecules form a cofacial dimer, both the x-and y-polarized dipoles are parallel (or antiparallel) as mentioned above (Fig. A similar blue shift of the Q-band has also been reported for Al III [47,139], Ge IV [34], Fe III [140], Mn III [49], and Cr III [141] derivatives. This has been exemplified by Gasyna et al [137] on the basis of the The optical absorption spectra of μ-oxo dimers of the Si IV complex of phthalocyanine derivatives in cyclohexane (Fig.…”

Study of the sensor response of spun metal phthalocyanine films to volatile organic vapors using surface plasmon resonance

“…The deposition of some MPcs using their solutions in TFA has already been described in the literature [36,37]. [39]. The UV-vis absorption spectrum of the spun ClAlPc film ( Fig.…”

Block Copolymer Micelles with Near Infrared Metal Phthalocyanine Dyes for Laser Induced Writing

“…[31] In order to dissolve Co II -Pc in toluene, we employed amphiphilic block copolymer micelles in which polar cores are preferentially coordinated with the dye molecules and at the same time non-polar coronas guarantee the stability in solution. The absorption spectra of a well dispersed Co II -Pc dye in a 0.5 wt.-% PS-b-P4VP1 solution show the appearance of two peaks in the NIR to visible region in Figure 2a.…”