Azides and Porphyrinoids: Synthetic Approaches and Applications. Part 2-Azides, Phthalocyanines, Subphthalocyanines and Porphyrazines

Abstract

The reaction between organic azides and alkyne derivatives via the Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) is an efficient strategy to combine phthalocyanines and analogues with different materials. As examples of such materials, it can be considered the following ones: graphene oxide, carbon nanotubes, silica nanoparticles, gold nanoparticles, and quantum dots. This approach is also being relevant to conjugate phthalocyanines with carbohydrates and to obtain new sophisticated molecules; in such way, new systems with significant potential applications become available. This review highlights recent developments on the synthesis of phthalocyanine, subphthalocyanine, and porphyrazine derivatives where CuAAC reactions are the key synthetic step.

Keywords: azides; click chemistry; photodynamic therapy; photoinactivation; phthalocyanines; porphyrazines; subphthalocyanines.

Figure 1

General structures of phthalocyanine (Pc), subphthalocyanine (SubPc) and porphyrazine (Pz).

Scheme 1

Synthetic strategy used to immobilize ZnPc1 on single-walled carbon nanotubes (SWCNTs) and on reduced graphene oxide (rGO).

Scheme 2

Synthetic strategy used to obtain the hybrid ZnPc-MWCNT.

Scheme 3

Synthetic methodology used to prepare CoPc2-GONS and CoPc3-GONS assemblies.

Scheme 4

Synthesis and conjugation of ZnPc4a–c with azide-functionalized silica nanoparticles.

Scheme 5

Synthetic strategy used to prepare the triazole ZnPc5c@MSN, the precursors ZnPc5a–c and the alkyne-silica nanoparticles.

Scheme 6

Preparation of nanocomposites AuNPs-ZnPc6 and AuNPs-InPc6.

Scheme 7

Synthetic strategy used for the preparation of npAu-N₃ and npAu-ZnPc7.

Scheme 8

Schematic representation of the synthesis of FePc7-CdSe/ZnS quantum dots (QDs).

Scheme 9

Synthesis of the glycosylated CuPc9.

Scheme 10

Synthetic strategy used in the preparation of ZnPc10a/10b and ZnPc11a/11b.

Scheme 11

Synthesis of glycosylated azaphthalocyanines ZnPc14a,b.

Scheme 12

Synthetic strategy used to prepare the glycosylated phthalocyanines ZnPc16 and ZnPc17.

Scheme 13

Synthetic strategy used to prepare axial carbohydrates ZnPc20.

Figure 2

Structures of the galactoconjugated ZnPc21–24.

Scheme 14

Synthetic strategy used to prepare ZnPc27.

Scheme 15

Synthetic strategy used for the immobilization of ZnPc28 in l,l-PIAAPE.

Scheme 16

Synthesis of CuPc30 with different chain lengths of monomethyl ether polyethylene glycol (mPEG).

Scheme 17

Synthesis of polymers PS-ZnPc31 and PtBA-ZnPc31 and of the required precursors ZnPc31, PS-N₃, and PtBA-N₃.

Scheme 18

Synthesis of PMMEM-ZnPc31-EDMA.

Scheme 19

Synthesis of polymers PMMA-ZnPc33 and BCP-ZnPc33 and of their precursors.

Figure 3

Structures of the dendritic zinc(II) Pcs ZnPc34a and ZnPc34b, and of the azide 10 used in their preparation.

Figure 4

Structures ZnPc35 and ZnPc36 and of the azide mPEG-N₃ used in their preparation.

Scheme 20

Synthesis of the azide-functionalized silicon phthalocyanine SiPc39 used to graft polymer brushes containing acetylene pendant groups.

Scheme 21

Synthetic strategy used to immobilize ZnPc40 in the azido polystyrene PS-N₃.

Scheme 22

Schematic representation of the grafting of the azidobenzene diazonium salt in GCE (A) and of the click reactions with MPc41 (B).

Figure 5

Structures of Pc42, MPc42, CoPc43, and CoPc44.

Scheme 23

Synthetic procedures used in the preparation of ZnPc45.

Figure 6

Structure of C₆₀-ZnP-ZnPc46 triad.

Scheme 24

Synthetic strategy used for the preparation of the C₆₀-(ZnPc46)₂ triad.

Figure 7

Structures of the compounds used in the preparation of the Pc derivatives ZnPc48a,b.

Scheme 25

Synthetic access to ZnPc50 from ZnPc49.

Scheme 26

The synthetic strategy used in the preparation of subphthalocyanine SubPc4.

Scheme 27

The synthesis of porphyrazines MPz.