Original scientific paper

The Motion of the Benzene Molecules in the Host Lattices of M(NH₃)₂M’(CN)₄·2C₆H₆ Clathrates

L. Andreeva ; Institut za hemija, PMF, Univerzitet »Kiril i Metodij«, POB 162, Arhimedova 5, 91000 Skopje, Makedonija
B. Minčeva-Šukarova ; Institut za hemija, PMF, Univerzitet »Kiril i Metodij«, POB 162, Arhimedova 5, 91000 Skopje, Makedonija
V. Petruševski ; Institut za hemija, PMF, Univerzitet »Kiril i Metodij«, POB 162, Arhimedova 5, 91000 Skopje, Makedonija

Abstract

In our previous report1 we discussed host-guest interactions in a series of Hofmann-type clathrates of the general formula: M(NH3)2M’(CN)4-2C6H6, where M is Ni, Fe, Co, Zn, Mn and Cd and M’ is Ni. It was found that the splitting of the band due to CH out-of-plane vibration in benzene, at liquid nitrogen temperature, (at around 985 cm-1), increases as the volume of the tetragonal unit cell decreases. A similar behaviour we recorded in a series of benzene clathrate compounds (isostructural with Hofmann-type clathrates) in which the M’ metal was replaced by Pt or Pd, and it was interpreted as a consequence of a »free« rotation in the benzene molecules at room temperature but hindered at low temperatures. The magnitude of the splitting of this band, at liquid nitrogen temperatures, for all the clathrates studied was correlated with the volume of the tetragonal unit cell and with the effective ionic radii of the octahedrally coordinated metal M and the square- planar coordinated metal M’. The slope of Ai< vs, V(Unitcell) is =-100 cm"1 nm-3.

Keywords

Hrčak ID:

137279

URI

https://hrcak.srce.hr/137279

Publication date:

15.6.1992.

Visits: 921 *