title: Mixed copper-lanthanide metallomesogens.
abstract: This paper describes the first examples of heteropolynuclear metallomesogens that contain both a transition metal ion and a trivalent lanthanide ion. Adducts were formed between a mesomorphic [Cu(salen)] complex (salen=2,2'-N,N'-bis(salicylidene)ethylenediamine) with six terminal tetradecyloxy chains and a lanthanide nitrate (Ln=La, Gd). Different stoichiometries were found, depending on the lanthanide ion: a trinuclear copper-lanthanum-copper complex [La(NO(3))(3)(Cu(salen))(2)] and a binuclear copper-gadolinium complex [Gd(NO(3))(3)Cu(salen)]. The compounds exhibit a hexagonal columnar mesophase (Col(H)) over a wide temperature-range with rather low melting temperatures. Although the clearing point could be observed for the parent [Cu(salen)] complex, the mixed f-d complexes decomposed in the high-temperature part of the mesomorphic domain before clearing. On the basis of X-ray diffraction measurements and molecular modelling, a structural model for the mesophase of the metal complexes is proposed.
authors.affiliation: Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Leuven, Belgium. koen.binnemans@chem.kuleuven.ac.be
authors.forename: Koen
authors.initials: K
authors.lastname: Binnemans
authors.forename: Katleen
authors.initials: K
authors.lastname: Lodewyckx
authors.forename: Bertrand
authors.initials: B
authors.lastname: Donnio
authors.forename: Daniel
authors.initials: D
authors.lastname: Guillon