Tin(IV) Porphyrins Containing β‐Substituted Bromines: Synthesis, Conformations, Electrochemistry and Photophysical Evaluation

Abstract

Tin(IV) porphyrins containing bromine atoms at 2,3,12,13 -pyrrole positions are synthesised using four different bisaxial ligands; namely, chloro 2, hydroxo 3, phenolato 4 and 4-nitrophenolato 5. The compounds are characterised using 1 H NMR spectroscopy, ESI-MS and elemental analysis. Despite steric loading at the -pyrrole positions, the X-ray diffraction crystal structure analysis of 4 reveals a planar macrocyclic conformation. However, the structure of 5 shows a nonplanar conformation, with a predominant out-of-plane wave distortion mode. Normal-coordinate structural decomposition (NSD) analysis, as well as analysis of the Sn-N distances, shows that the relief of steric strain in 4 is through in-plane core elongation, [a] 3869 Scheme 1. Synthesis of tin(IV) porphyrins containing -bromine atoms. Figure 2. (a) ORTEP diagram of 4 with 50 % probability ellipsoids. (b) Side view of the macrocycle. (c) Crystal packing diagram.

DNA Targeting Long-Chain Alkoxy Appended Tin(IV) Porphyrin Scaffolds: Photophysical and Antimicrobial PDT Investigations

“…The λ max values are very similar to those of SnTPP­(Cl) 2 and SnTPP­(OH) 2 but the molar absorption coefficients (ε) are higher (for example, for SnTPP­(OH) 2 ε = 1.17 × 10 5 M –1 cm –1 ). Particularly, the ε values are higher for axial chloro substituted porphyrins than hydroxo compounds suggesting effective electronic perturbations by chloro axial ligands in these porphyrins . Usually, tin­(IV) porphyrins exhibit red fluorescence with quantum yield (ϕ) around 0.02 .…”

“…Particularly, the ε values are higher for axial chloro substituted porphyrins than hydroxo compounds suggesting effective electronic perturbations by chloro axial ligands in these porphyrins. 37 Usually, tin(IV) porphyrins exhibit red fluorescence with quantum yield (ϕ) around 0.02. 15 The fluorescence spectra of long-chain alkoxy tin(IV) porphyrins showed typical two banded emission maxima which are 10 nm hypsochromically shifted when compared to SnTPP(OH) 2 .…”

Sn(iv)-porphyrinoids for photodynamic anticancer and antimicrobial chemotherapy

“…18) and their photophysical properties were evaluated. 99 12a–d have intense B bands at ca. 435 nm in THF with different intensities and varying full width at half maximum (FWHM) values due to enhanced electronic communication between the axial ligands and the porphyrin ring.…”

Redox-active ligands – a viable route to reactive main group metal compounds

“…106 CV studies of the complexes of (Br 4 TPP) SnX (X = Cl, OH, OPh, p-(NO 2 )C 6 H 4 O) show two reversible reduction peaks, which are shifted to lower potentials versus non-brominated analogues due to the electron withdrawing effect of the β-bromine atoms. 107 Tin porphyrin complexes were found to promote the oxidative cleavage of vicinal diols (Fig. 8a).…”