Applications of Photoinduced Phenomena in Supramolecularly Arranged Phthalocyanine Derivatives: A Perspective

Abstract

This review focuses on the description of several examples of supramolecular assemblies of phthalocyanine derivatives differently functionalized and interfaced with diverse kinds of chemical species for photo-induced phenomena applications. In fact, the role of different substituents was investigated in order to tune peculiar aggregates formation as well as, with the same aim, the possibility to interface these derivatives with other molecular species, as electron donor and acceptor, carbon allotropes, cyclodextrins, protein cages, drugs. Phthalocyanine photo-physical features are indeed really interesting and appealing but need to be preserved and optimized. Here, we highlight that the supramolecular approach is a versatile method to build up very complex and functional architectures. Further, the possibility to minimize the organization energy and to facilitate the spontaneous assembly of the molecules, in numerous examples, has been demonstrated to be more useful and performing than the covalent approach.

Keywords: Charge-transfer; PDI; UV-Vis; carbon allotropes; cyclodextrins; energy-transfer; fluorescence; fullerene; hydrogen bonds; micelles; photocatalysis; photodynamic therapy; sensors; solar cells; supramolecular assembly; time-resolved spectroscopy; π-π interaction.

Scheme 1

General structure of the phthalocyanine macroring, where M is the central metal ion or H₂ in the case of the free base. R is the potential functionalization on the phthalocyanine periphery.

Figure 1

(A) Chemical structure of the tetrasubstituted 15-crown-5 ethers phthalocyanine derivative and the two biomolecules. (B) Schematic representation of the formation of Pc/poly(l-lysine) assemblies. Reprinted with permission from ref. [52]. Copyright 2017 American Chemical Society.

Figure 2

Scheme of the CN⁻ sensing mechanism by supramolecular assembly GQDs-CoPc proposed in the Ref [57].

Figure 3

Energy levels of electron donor and electron acceptor during the electron-hole couple formation and separation.

Figure 4

Chemical structure of Pc and PDI reported in the reference [69].

Figure 5

Melanine substituted Pc used to form the supramolecular assembly with functionalized PDI derivative [71]. In (A,B) the two possible supramolecular configurations are reported according to the authors’ rationale [71].

Figure 6

Chemical structures of the bis-(A) and mono (B) substituted PDIs used to form the supramolecular adducts with the ZnPc reported in the reference [72].

Figure 7

(A) Double charged PDI derivative used to form the photoactive dyad with ZnPc. (B) Asymmetrically substituted perylene imide linked to TiO₂ to build up a dye sensitized solar cell [76].

Figure 8

Chemical structure of (2,3,9,10,16,17,23,24-octakis(octyloxy))-29H,31H-phthalocyanine used in [81].

Figure 9

Chemical structures of the three carboxylated phthalocyanines used to form the electrostatically bounded supramolecular dyads with Li⁺@C₆₀ [84]. (A–C) are the three phthalocyanine derivatives used to form complexes with fullerenes.

Figure 10

(A) 18-crown tetra functionalized ZnPc and (B) C₆₀ derivative chemical structures [85].

Figure 11

RuPc/squaraine derivative/RuPc photoactive supramolecular assembly reported in [86].

Figure 12

C₆₀ fulleropyrrolidine chemical structure.

Figure 13

(A) Pyridine functionalized fulleropyrrolidine and (B) BODIPY-substituted ZnPc proposed in [92].

Figure 14

(A) ZnPcs derivative sandwich formed by the action of K⁺. (B) C60 derivative used to form the triad with (A) according to [97].

Figure 15

(A) Star-shaped zinc phthalocyanines and (B) fulleropyrrolidine derivative chemical structures used in [99].

Figure 16

Structures of (A) phthalocyanine directly linked to four pyrene entities and (B) porphyrin linked to four entities of pyrene [101].

Figure 17

Silicon(IV) phthalocyanines axially substituted with permethylated β-cyclodextrin used in [104].

Figure 18

Molecular structures of the oligothiophene ligands used in [108].

Figure 19

Interaction between CNT and pyrene functionalized with the imidazole entity according to the mechanism proposed in [113].

Figure 20

Six different ZnPcs chemical structures used to interact and to improve CNTs solubilization. ZnPc derivative (A) and ZnPc with X = O-(CH₂)₆-O and n = 27, reported in (B), appear particularly efficient in the SWCNTs solubilization [114].

Figure 21

Cationic zinc phthalocyanines used to improve SWCNTs solubilization in water [7].

Figure 22

Schematization of the photo-induced formation of the radical O₂^•− and the formation of the hydroxyl radical (OH^•).

Figure 23

Chemical structures of the perylene derivative PDI used in [124].

Figure 24

Chemical structure of ZnPc with three 15-crown-5 ether functional groups and one carboxyl group [134].

Figure 25

Schematized Jablonski’s diagram for a typical PS.

Figure 26

Octahoxosubstituted ZnPc bearing two adamantane groups [140].

Figure 27

Chemical structure of Si(IV)Pc derivative modified with an axial pyridinium and an axial adamantane moiety used in ref [146].

Figure 28

Chemical structures of poly-β-cyclodextrin (A), zinc phthalocyaninetetrasulfonate (B) and adamantylnitroaniline (C) derivatives [151].

Figure 29

Curdlan chemical structure [161].

Figure 30

(A) Octacationic ZnPc derivative (octakis(1-methyl-3-pyridiniumoxy)-ZnPc) [51] and (B) tetra-anionic pyrene derivative (1,3,6,8-pyrenetetrasulfonic acid) [170].

Figure 31

(A) dendrimeric ZnPc; (B) PEG–PLL used in [171].

Figure 32

(A) crown-ether and (B) phosphoryl-containing derivatives [177].

Figure 33

Schematic structure of compound Azo 1 [178].

Figure 34

Biotin chemical structure [185].

Figure 35

Chemical structure of the free base 4-((5-(trifluoromethyl)pyridin-2-yl)oxy)phthalocyanine utilized to assemble the hybrid structures with GQDs in the ref. [191].