Molecular and Crystal Structures of Some Fluorocymantrenes

The crystal and molecular structures of the fluorocymantrenes [(C5H4F)Mn(CO)3] and [(C5H5−nFn)Mn (CO)2(PPh3)] (n = 1–3) have been studied. The influence of the phosphine for carbonyl substitution on the bond parameters is larger than the influence of the increasing fluorine content. In most cases the Mn → P vector is in a transoid position relative to the fluorine substituents, and therefore the conformational parameters of the PPh3 propeller are in these cases very similar. The crystal structures show many intermolecular C–H⋯O hydrogen bonds and only very few C–H⋯F hydrogen bonds. Graphic Abstract The influence of the phosphine for carbonyl substitution on the bond parameters of the fluorocymantrenes [(C5H4F)Mn(CO)3] and [(C5H5−nFn)Mn (CO)2(PPh3)] (n = 1–3) is larger than the influence of the increasing fluorine content.

Vibrational relaxation dynamics of β-carotene and its derivatives with substituents on terminal rings in electronically excited states as studied by femtosecond time-resolved stimulated Raman spectroscopy in the near-IR region

Time-resolved near-IR stimulated Raman spectroscopy indicates acceleration of vibrational relaxation in carotenoids by carbonyl substitution on their peripheral rings.