Modeling of End-On (&mgr;-Peroxo)dicopper(II) Complexes.
A force field for (&mgr;-peroxo)dicopper(II) complexes was developed, based on a well-established parameter set for copper(II) complexes, the structural and spectroscopic data of a (&mgr;-peroxo)dicopper(II) complex with tris(2-pyridylmethylamine) donors and a series of (&mgr;-peroxo)dicobalt(III) compounds. This force field is shown to well reproduce the structural properties of the available structures of (&mgr;-peroxo)dicopper(II) and (&mgr;-peroxo)dicobalt(III) complexes, and it was used to compute a series of (&mgr;-peroxo)dicopper(II) compounds with two tris(2-pyridylmethylamin) units linked by different organic spacers at a 5-pyridyl position at each tetradentate moiety. The computed structures and strain energies indicate that (i) in the compound with an ethyl spacer group the ligand induces a considerable strain and distortion in the &mgr;-peroxo product, and these effects compensate the favorable entropy effects due to the ligand preorganization, in agreement with the published experimental results; (ii) the (&mgr;-peroxo)dicopper(II) compound with the propyl-linked ligand is relatively unstrained and structurally very similar to the parent compound; and (iii) larger spacer groups lead to rather distorted (&mgr;-peroxo)dicopper(II) products.
Comba
Peter
P
Anorganisch-Chemisches Institut der Universität, Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany, and Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218.
Hilfenhaus
Peter
P
Karlin
Kenneth D.
KD