Coordination self-assembly through weak interactions in meso-dialkoxyphosphoryl-substituted zinc porphyrinates

Sergey E Nefedov (1) , Kirill P Birin (2) , Alla Bessmertnykh-Lemeune (3) , Yulia y Enakieva (2) , Anna A. Sinelshchikova (2) , Yulia G. Gorbunova (1, 2) , Aslan Tsivadze (1, 2) , Christine Stern (3) , Yuanyuan Fang (4) , Karl Kadish (4)

1 IGIC - N. S. Kurnakov Institute of General and Inorganic Chemistry
2 A.N. Frumkin Institute of Physical Chemistry and Electrochemistry
3 ICMUB - Institut de Chimie Moléculaire de l'Université de Bourgogne [Dijon]
4 Department of Chemistry [University of Houston]

The self-assembly of seven zinc 10-(dialkoxyphosphoryl)-5,15-diarylporphyrinates Zn5-Zn11 containing different substituents at the phosphonate and aryl groups was investigated. Single crystals of Zn5-Zn9 complexes were grown under the same conditions and analyzed by X-ray structural analysis. A supramolecular self-assembly is observed in all crystals through weak coordinative bonding of the phosphoryl group of one porphyrin molecule to the zinc(II) ion of a second porphyrin molecule. The geometry of the porphyrin macrocycle is similar in all of the studied crystals and the central zinc atom in each case adopts a distorted tetragonal pyramidal environment. However, the Zn5-Zn7 porphyrins display a 1D polymeric structure while the Zn8 and Zn9 complexes exist as discrete cyclotetramers in the crystals. This data demonstrates that the non-coordinating meso-aryl substituents of meso-(dialkoxyphosphoryl)porphyrins influence their crystalline organization. A self-assembly of the Zn5-Zn11 complexes is also observed in toluene and chloroform solutions over a large temperature range (223-323K). According to NMR studies, the associates exhibit dynamic behavior. A well-defined supramolecular aggregate of complex Zn10 at 10-3 M in toluene and chloroform solutions was unambiguously characterized as a cyclotetramer [Zn10]4 by 1 H NMR spectroscopy at 223K. The structure of the Zn10 association in toluene and chloroform shows a concentration dependence. When a solution of Zn10 in toluene was diluted from 10-3 M to 10-5 M, the average number of molecules in the associated unit decreased to about two.

Domaines: Chimie de coordination; Chimie organique

Sergey E Nefedov, Kirill P Birin, Alla Bessmertnykh-Lemeune, Yulia y Enakieva, Anna A. Sinelshchikova, et al.. Coordination self-assembly through weak interactions in meso-dialkoxyphosphoryl-substituted zinc porphyrinates. Dalton Transactions, 2019, 48 (16), pp.5372-5383. ⟨10.1039/C9DT00706G⟩. ⟨hal-02379937⟩