Assemblies based on the directing effect of non-classical W18 anionic clusters and the rod-like trans-1,2-di-(4-pyridyl)-ethylen (bpe)

Two polyoxometalate (POM) supramolecular assemblies based on W18 clusters and the rigid organic trans-1,2-di-(4-pyridyl)-ethylen (bpe) have been synthesized and fully characterized, namely (H2bpe)3.5H2[SbW18O60]·5H2O (1), and (H2bpe)5[Ni4(AsW9O34)2(H2O)2]·3H2O (2). Compounds 1–2 are formed from organic bpe cations and different polytungstate anions: pseudo-Dawson-type [SbW18O60]9− in 1 and sandwich-type [Ni4(H2O)2(AsW9O34)2]10− in 2. Both of compounds 1–2 crystallize in a low-symmetrical space group of P-1 and consist of a complicated supramolecular network based on non-covalent intermolecular weak interactions, including hydrogen bonding and π···π stacking. The multipoint hydrogen bonding interactions constitute the structural feature in two supramolecular frameworks. The UV–vis, fluorescence and electrochemistry properties are also studied.

Graphical abstractTwo polyoxometalate-based supramolecular assemblies built upon W18 clusters and the rigid organic trans-1,2-di-(4-pyridyl)-ethylen (bpe) have been synthesized and characterized.Figure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights► Sb3+ has a larger ionic radius to prevent the formation of the sandwich-type polyoxometalate cluster. ► Non-covalent interactions play important roles in the self-organization process. ► Polyanion can structure the conjugated organic molecule into a parallel and ordered arrangement. ► Polyanion-based hybrid is a potential candidate in the modified material for electrode.