Spectroscopic and Theoretical Study of a Mononuclear Manganese(III) Complex Exhibiting a Tetragonally Compressed Geometry

• Published in: Inorganic chemistry Vol. 47; no. 2; pp. 439 - 447
• Main Authors: Scheifele, Quirin, Riplinger, Christoph, Neese, Frank, Weihe, Høgni, Barra, Anne-Laure, Juranyi, Fanni, Podlesnyak, Andrei, Tregenna-Piggott, Philip L. W
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 21.01.2008
• Subjects: Biochemistry; Compressed; Density functional theory; Distortion; Ligands; Mathematical models; Neutron scattering; Spectroscopy
• DOI: 10.1021/ic701665u
• ISSN: 0020-1669

Inelastic neutron scattering and high-field electron paramagnetic resonance data are presented for [Mn(bpia)(OAc)(OCH3)](PF6), where bpia is bis(picolyl)(N-methylimidazole-2-yl)amine. Modeling of the data to the conventional fourth-order spin-Hamiltonian yielded the following parameters:  D = 3.526(3) cm-1, E = 0.588(6) cm-1,= −0.00084(7) cm-1,= −0.002(2) cm-1,= −0.0082(5) cm-1, g x = 1.98(1), g y = 1.952(6), and g z = 1.978(5). The complex is of particular interest given the biochemical activity and the unusual stereochemistry distinguished by a rare example of a tetragonally compressed octahedron and a pronounced angular distortion imposed by the tetradentate tripodal bpia ligand. Ligand field, density functional theory, and complete active space self-consistent field ab initio calculations are presented that aim to relate the spectroscopic data to the molecular geometry.