VIBRATIONAL STRUCTURE OF C-84 AND SC-2-AT-C-84 ANALYZED BY IR SPECTROSCOPY

The isomer III of Sc-2@C-84 was Separated by multi-cycle HPLC purifica tion. We present temperature dependent IR absorption measurements of S c-2@C-84 which have been performed between 50 and 300 K and between 40 0 and 5000 cm (-1), respectively. The vibrational structure of the end ohedral compound is compared to the structure of unfilled Css We find a strong overall broadening of the vibrational modes in Sc-2@C-84 Also some of the vibrational absorption lines are strongly enhanced if com pared to the spectrum for the empty cage. With decreasing temperature, a dramatic narrowing of the lines in the spectral range between 700 a nd 800 cm(-1) is observed. (C) 1997 Elsevier Science B.V.