Photomagnetic octacyanotungstates

X-ray can be used as a tool to induce modifications in molecular materials.1 Interestingly, some recent studies have shown that X-ray can also induce reversible switching, for instance low spin to high spin conversion on Fe(II) metal centers in spin crossover (SCO) complexes,2,3 or an electron transfer (ET) between Fe and Co ions through the CN bridge.4 In this proposal, we would like to study an other class of switchable compounds based on [W(CN)8]4- units using X-ray as the source of excitation. X-ray Absorption Near Edge Structure (XANES) and X-ray Magnetic Circular Dichroism (XMCD) will be exploited to determine (a) the switching mechanism and (b) the spin and orbital moments of the metastable state. These studies will be completed by high resolution X-ray diffraction at BM01 to elucidate the structure of the metastable states.