Knowledge Bank

A hindered internal rotation in the molecules of organometallic compounds of transition metals in organic and liquified noble gas solutions was studied using FTIR and Raman spectroscopy in a wide temperature range. It was demonstrated that rotational exist due to the internal rotation about single bonds between the transition metal and carbon atoms (in ``staircase” carbonyl pi-complexes of Fe, Mn, Cr, Mo, W), transition metal and non-transition element (in the complexes Cp(Co)2Fe$M\prime$ X2R and [Cp(Co)2Fe]2$M\prime$X2, $M\prime$ = Ge, Sn Cp = cyclopentadienyl), and between two transition metals (in binuclear complexes [Cp(CO)2M]2), M = Fe, Ru). The rotation of the M[CO)3- fragment was found in the ferrol type clusters of Ru and Re, where this group is pi-coordinated to the double bonds of metallacyclopentadienyl ring. The influence of different factors on the energy difference between rotational and on the rotational barriers is discussed.