title: Inelastic and elastic neutron scattering studies of the vibrational and reorientational dynamics, crystal structure and solid-solid phase transition in [Mn(OS(CH₃)₂)₆](ClO₄)₂ supported by theoretical (DFT) calculations.
abstract: The vibrational and reorientational dynamics of CH3 groups from (CH3)2SO ligands in the high- and low-temperature phases of [Mn(OS(CH3)2)6](ClO4)2 were investigated by quasielastic and inelastic incoherent neutron scattering (QENS and IINS) methods. The results show that above the phase transition temperature (detected earlier by differential scanning calorimetry (DSC) at TC5(c)=222.9K on cooling and at TC5(h)=225.4K on heating) the CH3 groups perform fast (τR≈10(-12)-10(-13)s) reorientational motions. These motions start to slow down below TC5(c) Neutron powder diffraction (NPD) measurements, performed simultaneously with QENS and IINS, indicated that this phase transition is associated with a change of the crystal structure, too. Theoretical infrared absorption, Raman and inelastic incoherent neutron scattering spectra were calculated using DFT method (B3LYP functional, LANL2DZ ECP basis set (on Mn atom) and 6-311+G(d,p) basis set (on C, H, S, O atoms) for the isolated equilibrium model (isolated [Mn(DMSO)6](2+) cation and ClO4(-) anion). Calculated spectra show a good agreement with the experimental spectra (FT-IR, RS and IINS). The comparison of the results obtained by these complementary methods was made.
authors: Faculty of Chemistry, Jagiellonian University, ul. Ingardena 3, 30-060 Kraków, Poland. Electronic address: szostak@chemia.uj.edu.pl.
authors: Elżbieta
authors: E
authors: Szostak
authors: Faculty of Chemistry, Jagiellonian University, ul. Ingardena 3, 30-060 Kraków, Poland; Frank Laboratory of Neutron Physics, JINR, 141980 Dubna, Russia.
authors: Joanna
authors: J
authors: Hetmańczyk
authors: Faculty of Chemistry, Jagiellonian University, ul. Ingardena 3, 30-060 Kraków, Poland.
authors: Anna
authors: A
authors: Migdał-Mikuli
mesh_terms: D056831:Coordination Complexes / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004548:Elasticity; D008958:Models, Molecular; D008968:Molecular Conformation; D033363:Neutron Diffraction; D010472:Perchlorates / Q000737:chemistry*; D044367:Phase Transition; D011789:Quantum Theory; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D013696:Temperature; D014732:Vibration
chemical_list: D056831:Coordination Complexes; D010472:Perchlorates
keywords: Crystal structure and molecular reorientations; Density functional theory (DFT); Hexadimethylsulfoxidemanganese(II) chlorate(VII); Inelastic and quasielastic incoherent neutron scattering (IINS and QENS); Neutron powder diffraction (NPD)