Investigating the Photochemical Properties of a Clickable Silicon (IV) Phthalocyanine Core

Abstract

In this study, a new azido-functionalized silicon(IV) phthalocyanine (SiPcN3) was synthesized and comprehensively characterized, revealing its promising photochemical characteristics. Despite the common challenges associated with crystallizing phthalocyanine-based compounds, SiPcN3 was successfully obtained as single crystals in the monoclinic P21/c space group. The incorporation of -N3 groups not only enhanced the compound's solubility and thermal stability but also introduced a reactive site suitable for future functionalization via copper-catalyzed azide-alkyne click chemistry. The molecular design enables straightforward integration into extended macromolecular systems, such as covalent organic frameworks (COFs) or cross-linked polymers. UV-Vis and photoluminescence analyses demonstrated intense Q-band absorption in the red region and tunable emission characteristics. The measured singlet oxygen quantum yield (Phi Delta = 0.14) indicates moderate photosensitizing activity, but this performance can potentially be enhanced through appropriate derivatization, improving its applicability in photodynamic therapy (PDT). Overall, these findings position SiPcN3 as a structurally versatile and functionally adaptable molecular platform, with promising potential for future development of PDT agents, photocatalytic/photooxidative materials, and optoelectronic devices, especially when embedded into porous or cross-linked polymeric networks.