W0279

Structural Studies of the Effects of Doping the Cluster Compound Ti₂Nb₆Cl₁₄O₄ with In⁺ or Tl⁺ Ions. Michael Essig, Ekaterina Anokhina, Cynthia Day, and Abdessadek Lachgar, Department of Chemistry, Wake Forest University, Winston-Salem, NC, 27109 USA

Our research focuses on investigation of structural and physical properties of a new family of compounds: niobium oxochlorides based on octahedral Nb₆ clusters and containing Ti³⁺ as a counterion. If the niobium cluster is paramagnetic, these compounds have the potential for interesting magnetic interactions between the cluster and titanium ions due to short Nb-Ti distances.

We have recently reported the synthesis and crystal structure of Ti₂Nb₆Cl₁₄O₄ (I).^[1] We have investigated the possibility of altering the electronic configuration of the diamagnetic cluster in (I) by doping this material with monovalent cations that can fit into cavities present in the cluster framework.

The doping of (I) with indium and thallium resulted in the formation of M_0.2Ti₂Nb₆Cl_13.8O_4.2 (M = In, Tl) in which the M⁺ ions partially occupy these cavities. The crystal structure analysis indicated that the additional charge provided by M⁺ ions is compensated by substitution of some chlorine by oxygen which leads to the cluster electronic configuration being intact. We will present a model of this disorder and discuss the possibility of In-In interactions in these phases.

^[1] E.V. Anokhina, M.W. Essig, A. Lachgar, Angew. Chem. Int. Ed. 1998, 37, 522-525.