Structural characterization of the trans-equatorial isomer of (aqua)(ethylenediamine-N,N,N '-tripropionato)chromium(III) trihydrate, [Cr(edtrp)(H2O)]center dot 3H(2)O

Abstract

The structure of trans-equatorial [Cr(edtrp)(H2O)]. 3H(2)O (edtrp(3-) is the anion of ethylenediamine-N,N,N'-tripropionic acid) was determined by single crystal X-ray diffraction. The chromium(III) ion is surrounded octahedrally by the two nitrogen and three oxygen atoms of the quinquedentate edtrp(3-), forming a five-membered diamine ring and the three six-membered beta-propionato chelate rings. The remaining coordination position is occupied by the H2O ligand. The crystal structure conformation is compared to the result of recent molecular mechanics analysis. The ring strain of R and G chelate rings was found to be in agreement with the previously proposed mechanisms for the C-N bond cleavage and recombination.