Infrared spectroscopy of oxygen bond systems

Electronic structures of hydroxylated low index surfaces of rutile and anatase-type titanium dioxide

“…24 Despite that there were endless debates about the characteristic vibrational peaks of different types of hydroxyl groups, experimental and theoretical studies on the vibrational spectra confirmed the stable existence of surface hydroxyl groups. [24][25][26][27][28] material being rich of surface hydroxyl groups, which showed good catalytic activity and photo-electron performances. 20 Mahdavi-Shakib et al evaluated the thermal stability of partial anatase and the rutile crystal face using experiments and DFT calculations, and redistributed the vibration frequency peaks of the pyrolytic hydroxyl groups.…”

Synthesis and Characterization of Rhenium(V) Oxo Complexes Bearing PNP-Pincer Ligands

“…ESI-MS measurements showed a [ Ph PNP-ReO 2 (PPh 3 )] + fragment ( m / z 956.1893) for 1 , while for 2 predominantly a [ t Bu PNP-ReO 2 ] + fragment ( m / z 614.2302) was observed. Finally, IR measurements showed strong vibrations at 792 and 790 cm –1 for 1 and 2 , respectively, which falls within the typical region for ν asym (ReO) of trans -dioxorhenium complexes (775–825 cm –1 ). − These combined spectroscopic features indicate that the PNP-pincer ligand is in a meridional position for both complex 1 and 2 and that the rhenium metal bears two oxo groups trans to each other, while the third ligand is trans to the pyridyl nitrogen. The third ligand is a coordinated PPh 3 trans to the pyridine nitrogen in the case of complex 1 , while 2 bears an iodide ligand on that position.…”

“…ESI-MS showed a [PNP-ReCl 2 O] + fragment for both 3 and 4 ( m / z 748.0396 and 772.2371, respectively) and an additional [ Ph PNP-ReCl 2 O-PPh 3 ] + fragment for 3 ( m / z 1010.1475), likely due to residual PPh 3 in the reaction mixture, which coordinates to the complex in the mass spectrometer. IR spectroscopy shows strong vibrations at 988 and 990 cm –1 for 3 and 4 , respectively, which can be assigned to the ReO vibration, typically found in the 955–995 cm –1 region . From these spectroscopic features it can be concluded that 3 and 4 also have an overall C 2 molecular symmetry bearing a meridional PNP-pincer ligand.…”

“…IR spectroscopy shows strong vibrations at 988 and 990 cm −1 for 3 and 4, respectively, which can be assigned to the ReO vibration, typically found in the 955−995 cm −1 region. 20 From these spectroscopic features it can be concluded that 3 and 4 also have an overall C 2 molecular symmetry bearing a meridional PNP-pincer ligand. As C 2 symmetry is not possible with a heptacoordinated rhenium complex bearing an oxo and three chlorides, it can be concluded that one chloride is expelled as a counterion and the two remaining chlorides are coordinated trans to each other, with the oxo ligand trans to the pyridine nitrogen.…”