124561-77-9Relevant academic research and scientific papers
The polarized single-crystal visible spectrum of Mo2(O2CCPh3)4
Cotton, F. Albert,Zhong, Bianxiao
, p. 2256 - 2260 (2007/10/02)
The title compound crystallizes from CH2Cl2 as large yellow tetragonal crystals (P4/ncc) in which all Mo-Mo bonds are parallel to the crystal c axis and intermolecular interactions are only of the weak van der Waals type. The ideal formula of the substance is Mo2(O2CCPh3)4·3CH 2Cl2, but real crystals are incompletely solvated to varying degrees depending on thermal history. From polarized spectra at 6 K of such single crystals having different degrees of partial solvation, as well as from the study of several hot bands, it has been shown that the electronic absorption band with its origin at about 450 nm should be assigned to the 1A1g → 1A2u (δ → δ*) electronic transition. In axial polarization the principal progression-building vibration is the Mo-Mo stretch in the 1A2u state (ca. 370 cm-1), and hot-band studies give a ground-state frequency of ca. 410 cm-1, in good agreement with Raman spectra of other Mo2(O2CR)4 compounds. In the perpendicularly polarized spectra, there are progressions built on origins 239, 267, 495, and 546 cm-1 above the axial origin, and these can be attributed to vibronic transitions based on Eg vibrational modes.
