A series of new Co II -Ln III complexes with polynuclear {Co 2 Ln(NO 3 )(Piv) 6 } (Ln = La, Gd, Dy; Piv = pivalate) cores were prepared by self-assembly reactions or step-by-step assembly.[Co 2 Dy(NO 3 )(Piv) 6 (MeCN) 2 ] was used as the starting compound for the synthesis of the trinuclear analogue [Co 2 Dy(NO 3 )(Piv) 6 -(py) 2 ] (py = pyridine) and the pentanuclear complex [{Co 2 Dy-(NO 3 )(Piv) 6 }{CoL(Piv)(H 2 O)} 2 ][NO 3 ] 2 [L = 2,6-bis(2-pyridyl)-4-(4pyridyl)pyridine]. The effects of the coordination environment and temperature on the distortion of the Ln III coordination polyhedra were analyzed for a series of coordination compounds with M II 2 Ln III cores and close analogues. The distortion of the Ln III polyhedron depends on both the composition of [a] N.

The tetranuclear heterometallic complex [LiZn(piv)(py)] (1, where piv = pivalate and py = pyridine) has been successfully employed as a presynthesized node for the construction of four porous metal-organic frameworks (MOFs) [LiZn(R-bdc)(bpy)]·solv (2-R, R-bdc; R = H, Br, NH, NO) by reaction with 4,4'-bipyridine (bpy) and terephthalate anionic linkers. The [LiZn] node is retained in the products, representing a rare example of the rational step-by-step design of isoreticular MOFs based on complex heterometallic building units. The permanent porosity of the activated frameworks was confirmed by gas adsorption isotherm measurements (N, CO, CH). Three compounds, 2-H, 2-Br, and 2-NH (but not 2-NO), feature extensive hysteresis between the adsorption and desorption curves in the N isotherms at low pressures. The substituents R decorate the inner surface and also control the aperture of the channels, the volume of the micropores, and the overall surface area, thus affecting both the gas uptake and adsorption selectivity. The highest CO absorption at ambient conditions (105 cm·g or 21 wt % at 273 K and 1 bar for 2-NO) is above the average values for microporous MOFs. The photoluminescent properties of the prototypic 2-H as well as the corresponding host-guest compounds with various aromatic molecules (benzene, toluene, anisole, and nitrobenzene) were systematically investigated. We discovered a rather complex pattern in the emission response of this material depending on the wavelength of excitation as well as the nature of the guest molecules. On the basis of the crystal structure of 2-H, a mechanism for these luminescent properties is proposed and discussed.

1,2-Bis(pyrid-4-yl)ethylene (red) and 2-allylmalonate (blue) undergo a photoinitiated [2+2] crossed cycloaddition reaction in a 3D coordination polymer, accompanied with significant atomic movement and crystal decomposition.

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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 0 -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 (H 2 O) cleavage.