Photodynamic activity attained through the ruptured π-conjugation of pyridyl groups with a porphyrin macrocycle: synthesis and the photophysical and photobiological evaluation of 5-mono-(4-nitrophenyl)-10,15,20-tris-[4-(phenoxymethyl)pyridine]-porphyrin and its Zn(ii) complex

Abstract

This article compares a hydrophobic and photobiologically inert porphyrin synthon, (NPh)TPyPz, bearing a single meso-4-nitrophenyl group and three meso-pyridyl groups with a new photobiologically active metal-free porphyrin, P3N, and its zinc-complex, P3NZn.

Porphyrins in Photodynamic Therapy: A Review

“…Apart from CPs and APs, porphyrin PSs having no net charge have been explored as possible PDT agents under in vitro conditions (Figure 1.6.3.1). 97,[244][245][246][247][248][249][250][251][252][253] The most commonly used neutral porphyrins are 5,10,15,20-(tetraphenyl) porphyrin (H2TPP), [244][245][246][247][248][249][250] and 5,10,15,20tetra-(4-hydroxyphenyl) porphyrin (THPP). [254][255][256][257][258][259][260] The tetra-symmetric chlorin 5,10,…”

“…138,[254][255][256][257][258][259][260][261] Several publications have reported alternatives to the synthesis of the popular compounds with interesting physiochemical, spectroscopic and/or photobiological outcomes. 90,97,234,252,[262][263] Sengupta et al 252 reported synthetic alternatives to photobiologically inert (NPh)TPyP 264 which bears three meso-(4-pyridyl) substituents attached directly to the porphyrin ring along with a lone meso-(4-nitrophenyl) substituents. In contrast, the new synthons P3N and P3NZn had the pyridyl groups placed at a distal position through ester linkages.…”

“…Several studies have reported that ZnPPSs have shown higher ROS generation and/or 1 O2 generation capability than their free-base counterparts. 252 A preference for ZnPPSs for 1 O2 generation has been established through photophysical experiments. 278,287 These factors make ZnPPSs an attractive drug target in cPDT, aPDT and the inactivation of viruses.…”