Exploitation of knowledge databases in the synthesis of zinc(II) malonates with photo-sensitive and photo-insensitive N,N'-containing linkers.

Ekaterina N Zorina-Tikhonova,Ivan A Godovikov,Aleksandr S Chistyakov,Alexander A Korlyukov,Aleksei A Sidorov,Igor L Eremenko,Yan V Zubavichus,Eugenia D Voronova,Anna V Vologzhanina,Mikhail A Kiskin,Pavel V Dorovatovskii

doi:10.1107/s2052252518001641

Abstract

Photoinitiated solid-state reactions are known to affect the physical properties of coordination polymers, such as fluorescence and sorption behaviour, and also afford extraordinary architectures (e.g. three-periodic structures with polyorganic ligands). However, the construction of novel photo-sensitive coordination polymers requires an understanding of the factors which govern the mutual disposition of reactive fragments. A series of zinc(II) malonate complexes with 1,2-bis(pyridin-4-yl)ethylene and its photo-insensitive analogues has been synthesized for the purpose of systematic analysis of their underlying nets and mutual disposition of N-donor ligands. The application of a big data-set analysis for the prediction of a variety of possible complex compositions, coordination environments and networks for a four-component system has been demonstrated for the first time. Seven of the nine compounds possess one of the highly probable topologies for their underlying nets; in addition, two novel closely related four-coordinated networks were obtained. Complexes containing 1,2-bis(pyridin-4-yl)ethylene and 1,2-bis(pyridin-4-yl)ethane form isoreticular compounds more readily than those with 4,4'-bipyridine and 1,2-bis(pyridin-4-yl)ethylene. The effects of the precursor, either zinc(II) nitrate or zinc(II) acetate, on the composition and dimensionality of the resulting architecture are discussed. For three of the four novel complexes containing 1,2-bis(pyridin-4-yl)ethylene, the single-crystal-to-single-crystal [2 + 2] cycloaddition reactions were carried out. UV irradiation of these crystals afforded either the 0D→1D or the 3D→3D transformations, with and without network changes. One of the two 3D→3D transformations was accompanied by solvent (H2O) cleavage.

Highlights

Topotactic reactions in the crystals of coordination compounds may proceed keeping (e.g. 1D!1D, 2D!2D or 3D!3D) or changing (e.g. 0D!1D, 0D!2D, 1D!2D or 2D!3D, including transformations from interpenetrated to non-interpenetrated architectures) the periodicity of the complexes (Vittal, 2007; Vittal & Quah, 2017; Huang et al, 2017)
We consider the insufficient investigation of photoinitiated reactions a result of the factors that govern the mutual disposition of reactive fragments, which are not well understood
Solid-state photodimerization in zinc(II) carboxylates containing 1,2-bis(pyridin-4-yl)ethylene was carried out (Toh et al, 2005; Papaefstathiou et al, 2005); the bridging carboxylate groups make the distance between Zn centers as short as 3.82–3.85 A

Summary

Introduction

Topotactic reactions in the crystals of coordination compounds may proceed keeping (e.g. 1D!1D, 2D!2D or 3D!3D) or changing (e.g. 0D!1D, 0D!2D, 1D!2D or 2D!3D, including transformations from interpenetrated to non-interpenetrated architectures) the periodicity of the complexes (Vittal, 2007; Vittal & Quah, 2017; Huang et al, 2017). The reticular chemistry approach (Yaghi et al, 2003; Furukawa et al, 2013) to photoactive materials can be based on the replacement of a photo-insensitive ligand with its photosensitive analogue in architectures with desired disposition of reactive fragments. In this case, a chemist should determine which ligands form an isoreticular series. Dimethylmalonate (Me2mal) and diethylmalonate (Et2mal) anions (An) were used, as these fix the Zn:An ratio to 1:1 (to decrease the number of symmetrically independent anions in the unit cell) and have less coordination modes than the malonate anion (Gogoleva et al, 2017)

Results and discussion

Synthesis

Crystallography

Conclusions

Funding information