Thiacalixarene-Supported Irregular Co26 and Ni28 High-Nuclearity Clusters with Pyridyl-Diphosphonates: Strategies to Create Active Metal Sites and Fabricate Multicomponent Materials.

Two new irregularity high-nuclearity clusters [Co26(TC4A)6(HL)4Cl4(HCOO)4(CH3O)2(OH)2(DMF)10(H2O)5] (+ solvent) (Co26) and [Ni28(TC4A)6(HL)6(PO4)2(μ3-O)2Cl2(CH3OH)14(H2O)2(DMF)8][(CH3NH2CH3)4] (+ solvent) (Ni28) have been solvothermally synthesized by p- tert-butylthiacalix[4]arene (H4TC4A), transition metals (CoCl2·6H2O/NiCl2·6H2O), and 1-hydroxy-2-(3-pyridinyl)ethylidene-1,1-diphosphonic acid (H5L). The clusters were structurally characterized by single crystal X-ray diffraction, PXRD, TGA, and FT-IR spectrum and Raman spectrum. Co26 features a rodlike Co26 core constructed by six Co4-TC4A secondary building units (SBUs) and four HL4- with two extra cobalt ions. Ni28 cluster represents a flowerlike Ni28 core built from six Ni4-TC4A SBUs, six HL4-, and four additional nickel ions. The multidentate risedronic acid displaying various new coordination mode bonds with SBUs to assemble two nanoclusters that enable high density possible coordinatively unsaturated metal sites (PCUMSs). Co26 and Ni28 clusters can be directly dispersed on carbon paper (CP) and showed extraordinary oxygen evolution reaction (OER) activity due to the larger exposed liable coordination active metal sites. The thermodecomposition of both nanoclusters at different temperatures afforded serial multicomponent complexes.