Exploring The Coordination Modes Of A Keggin-Type [Znw12o40]6(-) Anionic Cluster: Bonding Patterns, Crystal Structure, And Semiconducting Properties

Polyoxometalate-based organic-inorganic hybrid compounds (POIHCs) have been greatly developed due to their wide application prospects, but the pursuit of their directed synthesis via molecular design still remains a challenge. Herein, we demonstrate that the coordination modes of the Keggin-type [ZnW12O40](6-) anion can be tuned, which leads to different semiconductor characteristics. Using the same building block, ligand, and metal ion (ZnW12, phen, Cu2+), we synthesized three new POIHCs with different bonding patterns by means of different coordination modes of ZnW12. The three POIHCs (H(2)phen){ZnW12O40[Cu(phen)(2)](2)} center dot 3H(2)O (1), {ZnW12O40[Cu(phen)(H2O)(2)] 2[Cu(phen)(H2O)]} n center dot 3H(2)O ( 2), and (Me4N)(2){ZnW12O40[Cu(phen)(H2O)](2)} n center dot 5H(2)O (3) (phen = 1,10-phenanthroline) have been structurally characterized by single-crystal X-ray diffraction. Compound 1 appears as a zero-dimensional coordination complex cluster, while compounds 2 and 3 are both 1D chain structures with different Cu2+ bridge linkages. Although these three POIHCs possess the same chemical components, their semiconductor properties are different, which is demonstrated by measurements of transient photocurrent and band gap (E-g) values. Furthermore, we carried out comparative experiments on the photoconductivity performance of compounds 1-3 and their photocatalytic reduction from O-2 to H2O2, indicating the significant influence of the energy level matching on the photocatalytic activity.