2-DIMENSIONAL SPATIAL-SPECTRAL ESR IMAGING OF DIFFUSION-BASED ON MOLYBDENUM(V)

The diffusion coefficients of Mo-V (as MoCl5) at 300 K in solutions of poly(acrylic acid) in dimethylformamide (DMF) have been measured by t wo-dimensional spatial-spectral electron spin resonance imaging (2D ES RI), at polymer contents of 5%, 10%, and 15% w/w in the solvent. The c oncentration dependence of the diffusion coefficients is consistent wi th the free volume theory. The central position of molybdenum complexe s in redox and acid-base catalysis, together with the possibilities op ened by this study, suggest that the method of ESRI based on Mo-V coul d become important for measuring transport properties and spatial char acteristics of reactions in heterogeneous catalysis. Further developme nts of the approach taken in this study are discussed.