A Heterometallic MOC Assembled from Cobalt-bisupported Keggin Subunits

The design and assembly of metal-organic complexes (MOCs) have attracted considerable attention, because of their diverse topologies and potential applications in areas such as catalysis and materials science [1 – 6]. Polyoxometalates (POMs), as a unique class of inorganic metal oxide clusters, have been regarded as excellent candidates to obtain MOCs due to their controllable shapes and sizes, and their high negative charges [7 – 18]. As important members of the POM family, the classical Keggin polyanions have been extensively studied [19 – 22]. Many Keggin polyanions have been modified by cationic metal complexes to obtain novel MOCs. The cationic metal complexes can play several roles: (i) charge compensation, (ii) covalent binding to subunits of the POM framework, and (iii) linking of polyanions into infinite extended networks. The bisupporting Keggin subunits are the most common examples [23 – 28], which can be roughly divided into three types regarding the coordinating oxygen atoms that connect the cationic metal complexes as shown in Scheme 1. As reported herein, we synthesized and characterized a new one-dimensional (1D) heterometallic MOC that Scheme 1. View of the three types of bisupported Keggin subunits.