Transcript Slajd 1
Rafał Topolnicki, University of Wrocław, Elwira Borawska, University of Białystok Dynamic properties of molecules study using inelastic incoherent neutron spectroscopy and computational quantum chemistry methods Frank Laboratory of Neutron Physics JINR Supervisor: Dorota Nowak, Ph.D. July 2011 Pentabromophenol Molecular Formula C6HBr5O Melting point 223-228 ºC Boiling point 352 ºC Water solubility Insoluble Appearance Light brown powder LD50 (rat) 200mg/kg Uses:Chemical intermediate Acta Crystallographica, Sec. E. Struct. Rep. Online 64 (2008) 1921 Pentachlorophenol Molecular Formula C6HCl5O Melting point 190-191 ºC Boiling point 309-310 ºC Water solubility 0.020 g/L at 30 °C Appearance White crystalline solid Pentachlorophenol is an organochlorine compound used as a pesticide and a disinfectant. Acta Crystallographica 15 (1962) 1164 Time of flight t – time of flight t0 – time when neutrons leave moderator L1 – path from reactor to sample L2 – path from sample to detector w – factor (scaling neutrons' energy to velocity) E0 – initial energy E1 – final energy Application of IINS and QC calculations in studies of properties of selected lutidines, Sylwia Dobkowska, Katarzyna Kilan, Adam Kowalczyk, Kamil Kuźma Types of internal vibration modes In general for any molecule containing N atoms we have 3N-6 possible vibration modes (or 3N-5 for linear molecule like CO2) For each mode we can assign characteristic frequency. Our goal is to connect frequencies visible on experimental spectrum with certain types of internal vibration in molecule C-Br Bending C-ring Torsion C-Br Stretching Calculated Intensiv 43.4 0.006 48.6 0.002 91.7 0.001 141.6 0.092 146.0 0.170 150.1 0.125 158.5 0.015 169.5 0.459 210.8 0.049 222.5 0.038 237.3 0.000 322.5 6.032 332.6 2.198 365.6 0.030 387.2 1.042 459.7 90.984 557.4 25.326 ATOMS Br-C Br-C OH-C Br-C Br-C Br-C Br-C ring Br-C Br-C Br-C O-C ring ring C-O O-H ring MODE Out of plane Out of plane Out of plane bending bending bending bending Out of plane stretching stretching stretching bending Out of plane Out of plane stretching Out of plane torsion Calculations Obtain CIF file which contain informations about loactions of all atoms in molecule and molecules in Wigner–Seitz cell, Build izolated molecule (or dimmer) and write positions of atoms in Z-matrix form, Execute DFT calculation using Gaussian09 programme Choose B3LYP correlation-exchange potential, Select proper functional base - 6-31G* Optimalize atoms placements, Calculate vibrations Analysis and visualization of results All calculations were preformed in ICM in Warsaw 318,78 cm-1 O-H Out of Plane 474,01 cm-1 CC ring deformation 316,26 cm-1 O-H Out of Plane in both molecues 365,94 cm-1 Pentabromophenol 318,78 cm -1 1088,11 cm -1 33,26 cm -1 275,41 cm -1 References Dynamika molekularna kryształów z rodziny polifenyli, J. W. Wąsicki, Wydawnictwa UAM, 1991 Molecular dynamics of eithisterone studied by 1H NMR, IINS and quantum mechanical calculations, Chemical Physics 317 (2005) 178-187 Fizyka chemiczna, J. M. Janik, PWN 1989 Thank you for your attention!