title: Conformational Stability and Spin States of Cobalt(II) Acetylacetonate: CASPT2 and DFT Study.
abstract: Electronic structure and conformation of bis(acetylacetonate) cobalt(II), Co(acac)2, a prototypical mediator in controlled radical polymerization of olefins, is reinvestigated. The ab initio multiconfigurational CASSCF/CASPT2 method is used to resolve the doubts stemming from density functional theory results. We assign the quartet ground state for a single molecule and point at tetrahedral conformation as the preferred one. Several density functionals are tested against the ab initio calculations, and their performance is assessed. The strength of intermolecular interactions in the crystal structure composed of square-planar Co(acac)2 molecules ( Burgess , J. ; et al. Acta Crystallogr. 2000 , C56 , 649 - 650 ) is estimated to be sufficient for their planarization (suggested by Matyjaszewski , K. ; et al. Chem.-Eur. J. 2007 , 13 , 2480 - 2492 ).
authors.affiliation: Department of Theoretical Chemistry, Jagiellonian University, ul. Ingardena 3, 30-060 Kraków, Poland, and Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, ul. Niezapominajek 8, 30-239 Kraków, Poland.
authors.forename: Mariusz
authors.initials: M
authors.lastname: Radoń
authors.affiliation: Department of Theoretical Chemistry, Jagiellonian University, ul. Ingardena 3, 30-060 Kraków, Poland, and Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, ul. Niezapominajek 8, 30-239 Kraków, Poland.
authors.forename: Monika
authors.initials: M
authors.lastname: Srebro
authors.affiliation: Department of Theoretical Chemistry, Jagiellonian University, ul. Ingardena 3, 30-060 Kraków, Poland, and Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, ul. Niezapominajek 8, 30-239 Kraków, Poland.
authors.forename: Ewa
authors.initials: E
authors.lastname: Broclawik