Heterocorrole Conformations: Little Saddling, Much Ruffling

Abstract

10-Heterocorrole complexes with oxygen, sulfur, and selenium at position 10 of the macrocycle and with the divalent ions of nickel, copper, and palladium were prepared and investigated. The focus was set on the size adaptation and matching mechanisms of cavity size versus ionic radius in corrole-type macrocycles. A full set of single-crystal X-ray analytical data revealed that in all but one case the N binding site of the ring-contracted tetrapyrrole was larger than necessary to bind the metal ion without deformation. In-plane size adaptation through M-N bond-length elongation by 2.5-3.2 % was effective, as well as pronounced out-of-plane ruffling of the macrocycle for those compounds with a more severe size mismatch. Such ruffling had been excluded for corroles previously, but is apparently the most efficient mechanism to adapt to small central ions.

Magnetic Diversity in Heteroisocorroles: Aromatic Pathways in 10-Heteroatom-Substituted Isocorroles

“…The unsubstituted isocorroles H 2 [10-IsoCor] and Ni­[10-IsoCor] sustain moderate diatropic currents of 5.6–9.8 nA/T along the C α –C meso bonds and the direct pyrrole–pyrrole bond (Figure ). Substituting the 10-CH 2 group with divalent groups with a π lone pair (i.e., X = NH, ,− O, ,, PH, and S ,− ) dramatically boosts the global diatropic ring current, clearly signifying global aromaticity. The results presented in Figure allow for several interesting observations.…”

Bioinspired Selenium‐Nitrogen Exchange (SeNEx) Click Chemistry Suitable for Nanomole‐Scale Medicinal Chemistry and Bioconjugation

“…Seleno-macrocycles (SeMCs) play a critical role in multidisciplinary fields spanning from metal ligand, [44] selfassembly [45] to functional materials. [46] However, the efficient preparation of SeMCs remains a severe challenge because of the limited selenylation methods, [47] especially for the underexplored selenylalkyne containing macrocycles because the intramolecular C(sp)-Se bond formation reaction suitable for constructing macrocycles has not been reported yet. Generally, the synthesis of selenylalkyne containing macrocycles is more challenging than ordinary macrocyclization as there are four consecutive atoms (SeÀ C�CÀ C) arranged in a linear geometry [48] (verified by the crystal structure of SeMC-13, Figure 3), which resulted in stronger ring tension and higher entropic penalty [49] involved in the ring-closing process.…”

Heterocorroles: corrole analogues containing heteroatom(s) in the core or at a meso-position

“…Bröring and co-workers 23 further studied Ni( ii ), Cu( ii ) and Pd( ii ) complexes of 10-heterocorrole ligands containing O, S, Se at 10-position (35–37) to understand macrocycle's adaptability towards metal ions of different sizes while forming complexes. The synthesis of Ni, Cu, and Pd derivatives of these corroles is shown in Scheme 15 .…”