Structural insights into ligand dynamics: correlated oxygen and picket motion in oxycobalt picket fence porphyrins.

ABSTRACT: Two different oxygen-ligated cobalt porphyrins have been synthesized and the solid-state structures have been determined at several temperatures. The solid-state structures provide insight into the dynamics of Co-O(2) rotation and correlation with protecting group disorder. [Co(TpivPP)(1-EtIm)(O(2))] (TpivPP = picket fence porphyrin) is prepared by oxygenation of [Co(TpivPP)(1-EtIm)(2)] in benzene solution. The structure at room temperature has the oxygen ligand within the ligand binding pocket and disordered over four sites and the trans imidazole is disordered over two sites. The structure at 100 K, after the crystal has been carefully annealed to yield a reversible phase change, is almost completely ordered. The phase change is reversed upon warming the crystal to 200 K, whereupon the o

SUBMITTER: Li J 

PROVIDER: S-EPMC3384769 | biostudies-literature | 2012 Jun

REPOSITORIES: biostudies-literature