Pressure-dependent luminescence spectroscopy of molybdenum(IV) oxo complexes

TY - JOUR

T1 - Pressure-dependent luminescence spectroscopy of molybdenum(IV) oxo complexes

AU - Lanthier, E.

AU - Bendix, Jesper

AU - Reber, C.

PY - 2010

Y1 - 2010

N2 - Luminescence spectra are reported for trans-[MoOCl(CN-t-Bu) 4]BPh4 and trans-[MoOF(pyridine)4]BPh 4. The maxima of the broad luminescence bands are at energies of 12000 and 13000 cm-1, respectively. Resolved vibronic structure involves the metal-oxo stretching mode with a vibrational frequency of approximately 950 cm-1 (Raman) in both compounds. The pressure behavior of the luminescence bands shows a distinct difference: a blue shift of +12 cm-1 kbar-1 is observed for [MoOCl(CN-t-Bu) 4]BPh4, and a red-shift of -8 cm-1 kbar -1 is obtained for [MoOF(pyridine)4]BPh4. At pressures above 25 kbar, the luminescence maximum of [MoOCl(CN-t-Bu) 4]BPh4 shows a change from a blue-shift to a red-shift and the Raman peak corresponding to the metal-oxo stretching mode at 954 cm -1 becomes broad and its maximum decreases with increasing pressure, leading to a strong deviation from the linear increase of +0.24 cm-1 kbar-1 observed at pressures below 25 kbar. These unusual pressure effects are rationalized in terms of the influence of pressure on the metal-ligand bonds and oxo-metal-ligand angles using DFT calculations.

AB - Luminescence spectra are reported for trans-[MoOCl(CN-t-Bu) 4]BPh4 and trans-[MoOF(pyridine)4]BPh 4. The maxima of the broad luminescence bands are at energies of 12000 and 13000 cm-1, respectively. Resolved vibronic structure involves the metal-oxo stretching mode with a vibrational frequency of approximately 950 cm-1 (Raman) in both compounds. The pressure behavior of the luminescence bands shows a distinct difference: a blue shift of +12 cm-1 kbar-1 is observed for [MoOCl(CN-t-Bu) 4]BPh4, and a red-shift of -8 cm-1 kbar -1 is obtained for [MoOF(pyridine)4]BPh4. At pressures above 25 kbar, the luminescence maximum of [MoOCl(CN-t-Bu) 4]BPh4 shows a change from a blue-shift to a red-shift and the Raman peak corresponding to the metal-oxo stretching mode at 954 cm -1 becomes broad and its maximum decreases with increasing pressure, leading to a strong deviation from the linear increase of +0.24 cm-1 kbar-1 observed at pressures below 25 kbar. These unusual pressure effects are rationalized in terms of the influence of pressure on the metal-ligand bonds and oxo-metal-ligand angles using DFT calculations.

M3 - Journal article

SN - 1477-9226

VL - 39

SP - 3695

EP - 3705

JO - Acta chemica Scandinavica. Series A: Physical and inorganic chemistry

JF - Acta chemica Scandinavica. Series A: Physical and inorganic chemistry

ER -