Organic Functionalization of Polyoxovanadates: Sb—N Bonds and Charge Control

摘要

Numerous approaches towards the utilization of polyoxo-metalates (POMs) require their direct covalent attachment to organic groups. This ranges from immobilization of POM catalysts on polymer matrices and integration of POMs into porous metal-organic frameworks (MOFs) to electrochromic hybrid systems. The synthesis strategies developed to date are predominantly not based on the formation of metal-organic bonds, but utilize other main-group elements as bonding mediators to link the organic functions to the POMs. These coupling reactions formally correspond to condensation of the POM cluster with alcohols or carboxylates (M—O— R), or amines (M=N—R), but also with organodiazenido, organophosphato, organosilyl, or organotin groups. However, these strategies primarily target polyoxomolybdates and -tungstates. Various types of subsequent reactions of the organic functions attached to the POM (for example, 1,3-dipolar cycloadditions ("click" chemistry), Sonogashira and Heck coupling reactions, or Diels-Alder reactions) emphasize the potential for the integration of such hybrid systems as building blocks into other structures. Polyoxovanadates, such as decavanadate, also exhibit interesting reactivities towards biomolecules, as exemplified by hydrolytic DNA cleavage, inhibition of oxygen consumption in membranes, or the inhibition of 6-phosphogluconate hydrogenase by tetravana-date.