[38]Octaphyrin bis-Sn(IV) complexes with unique coordination geometries

Abstract

Metal complexation of octaphyrin(1.1.1.1.1.1.1.1) triggers unique ring-fixation aptitudes or unexpected rearrangement (cleavage) reactions. In this paper, a unique complexation behavior of [38]octaphyrin upon tin(IV) metalation is showcased. Two new [38]octaphyrin bis-Sn(IV) complexes 2Sn and 3Sn were isolated and characterized as weakly aromatic molecules. While 2Sn with the [Formula: see text] molecular symmetry displayed a similar characteristic to octaphyrin bis-Si(IV) and bis-Ge(IV) complexes reported previously, 3Sn showed a different coordination mode that is fixed by intramolecular hydrogen bondings between pyrrolic NH and axially ligated OH on the tin ion as revealed by X-ray diffraction analysis. An unexpected dimeric structure was also observed during an attempt to grow crystals of 2Sn. These characteristic behaviors indicate that the ring-fixation aptitude of octaphyrin is quite sensitive to the nature of metal ions even for the same group 14 elements.

The p-Metal Porphyrins: from Specificity of Properties to Application in Medicine, Catalysis, and Optoelectronics

“…Most notably, they combine interesting spectroscopic and chemical properties as the luminescent properties and particular oxophilicity with the 14 group porphyrin complexes [26] or the coordination with two and three porphyrin N atoms only with the boron and tellurium complexes, respectively. [47] Many works [48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65] can be cited, in which using the maingroup porphyrin/phthalocyanine complexes as aluminumsubstituted heme, anticancer/phototeranoctic agents, prophotosensitizers/singlet oxygen sensitizers, template agents in the tetrapyrrole macrocycle synthesis, electron acceptor materials for organic electronics, and chemosensors were studied. Generalizations in the area under consideration have been undertaken in three reviews [27,48,66] where the earlier ones was mentioned and, in part, in two more reviews.…”