A THERMOCHEMICAL INVESTIGATION OF GUEST-HOST INTERACTIONS IN LABILE WERNER-CLATHRATES OF THE [NI(4-ETPY)(4)(NCS)(2)].G TYPE (G=METHYL DERIVATIVES OF BENZENE)

The stoichiometry of thermal decomposition has been studied for (I): [ Ni(4-EtPy)(4)(NCS)(2)] as a host complex as well as for its clathrates [Ni(4-EtPy)(4)(NCS)(2)].G where guest molecule G - toluene, (II): T, (III): o-xylene (o-X) and (IV): p-xylene (p-X). The loss of volatile c omponents proceeds in three steps (-2L, -1L, -1L) for I and in four st eps (-G, -2L, -1L, -1L) for II, III and IV. DSC and X-ray powder measu rements indicated a phase transition in all compounds under study. How ever, this process is overlapped by the escape of G in II and III. The differences in enthalpy changes are associated with different guest-h ost interactions in the particular clathrates. (C) 1997 Elsevier Scien ce B.V.