EXAFS data analysis of vitamin B-12 model compounds - A methodological study

In view of several controversial EXAFS results on cobalamins and B-12 model compounds published in the last ten years, a methodological study is prese nted to explain the origin of these controversial results and to propose ho w to improve EXAFS structural-parameter refinement. The advantages and limi tations of first-shell filtering, constrained refinement, and the importanc e of the mapping technique are described in order to suggest and encourage improvement of data-analysis codes. The conclusions can be generalized and applied to the EXAFS analysis of the majority of metal complexes.