Copper(II) phthalocyanine tetrasulfonate sensitized nanocrystalline titania photocatalyst: Synthesis in situ and photocatalysis under visible light

Solvent effects on molecular aggregation of highly water-soluble phthalocyanines

“…Phthalocyanines and related compounds are known as versatile dyestuffs and enjoy various applications in industrial and medical fields [4,5], e.g. non-linear optics [6], optical data storage [7], solar cells [8], charge-generating materials for photocopiers and laserprinters [9], elecrochromic displays [10,11], photosensitizers for solar cells (DSC) [12] and photocatalysts [13], those for photodynamic therapy (PDT) [14] of tumors and photodynamic antimicrobial therapy (PACT) [15], chemical probes for bio-imaging (photodynamic diagnosis (PDD) of cancer) [16], semiconductors [17] and synthetic metals [18], and are also well-known to undergo this kind of phenomenon [14,[19][20][21][22][23][24][25][26][27]. Aggregation of dye molecules is quite an interesting subject from a viewpoint of supramolecular chemistry [28] because this gives rise to significant changes in their physical properties.…”

“…Eventually aggregation of phthalocyanines produces dramatic spectral changes according to the manner of alignment of macrocycles due to exciton coupling between the chromophores [29][30][31]. However, this also may cause a serious problem in some of the aforementioned applications, in particular when their excited states are involved [12][13][14][15][16], because photo-excited dye molecules in aggregates are rapidly relaxed to their ground state and lifetimes of their excited states are significantly shortened and consequently their photochemical activities are considerably reduced [32,33]. This problem can be fatal for phthalocyanines in aqueous media.…”

Introduction

“…12 For example, the first step in photosynthesis in plants involves this phenomenon, where chlorophyll, or other similar macrocyclic compounds, plays the role as the dye. This phenomenon is applicable to water-splitting for fuel cells (artificial photosynthesis) [30] or degradation of pollutants in industrial wastewater (photocatalysis: The hole and excited electron can be used to oxidize and reduce another molecule in the vicinity of the dye, respectively) [21].…”

“…2 and 3). In recent decades, phthalocyanines enjoy a variety of industrial and medical applications [6][7][8], such as nonlinear optics [9], optical data storage [10,11], solar cells [12][13][14], charge-generating materials for photocopiers and laser printers [15], electrochromic displays [16,17], photosensitizers for solar cells [18], water splitting for fuel cells [19,20], photocatalysts [21], photodynamic therapy (PDT) of tumors [22][23][24][25], photodynamic antimicrobial therapy 11 When a metal ion is trivalent, the complex is represented as [M(Pc)X], where X denotes a monoanionic axial ligand. Likewise, [M(Pc)X 2 ] is for a complex of tetravalent cations.…”

Isonicotinic acid-ligated cobalt (II) phthalocyanine-modified titania as photocatalyst for benzene degradation via fluorescent lamp

“…Aside from the change in the central atom, addition of substituents on the phthalocyanine periphery can be done, which would influence the light absorption capabilities of the complex, thereby further enhancing TiO2 photosensitization. 10 Moreover, the substituents can be functionalized to serve as bridging ligands to TiO2 producing an efficient electron transfer from the phthalocyanine photosensitizer. This paper reports on axial ligation as a modification option on enhancing the electronic structure of phthalocyanines as photosensitizer to TiO2.…”