Electronic Structures of CO-Releasing Zero-Valent Metal-Organic Frameworks

We have developed a novel gas-phase approach to unique, low-valent metal-organic frameworks, exemplified by [Mo(CO)3(bipy)3/2]n (bipy = 4,4′-bipyridine) and [W(CO)3(bipy)3/2]n. The metal nodes are stabilised by carbonyl ligands (CO), which can be liberated upon visible light irradiation. CO ligands can be replaced with paramagnetic NO, and the magnetic moment distribution of these M–NO complexes will provide key insights into the electronic structures of the materials. We aim to use ID12 to directly probe the electronic structure of the metal atoms in the bulk product and as nanocrystalline coatings, using XANES at the Mo and W L2,3 edges, w/o in situ laser photolysis. Furthermore, analysis of the magnetic moment transfer from coordinated NO to the metal sites will be unravelled using XMCD will yield insights into the nature of the bonding that we expect to be fundamentally different to what is currently known for conventional, higher-valent MOFs.