Reduction of the bulky 8-annulene thorium complex [Th{COT(TBS)2}2] (COT(TBS)2 = η-C8H6(tBuMe2Si)2-1,4) by potassium yields the anionic compound {Th[COT(TBS)2]2}K·(DME)2, which was crystallographically characterized and is the first sandwich complex of Th(III). EPR spectroscopy indicates that the molecule possesses a 6d1 ground state. A structural comparison is made with the isostructural uranium(III) complex and the thorium(IV) parent compound.

A series of acyclic thiourea derivatives, designed to create a cleft with four hydrogen bond donors suitable for carboxylate recognition, have been prepared, and their ability to bind to N-protected amino acid carboxylate salts has been investigated. The crystal structure of one of the thioureas has been determined showing that it forms a hydrogen bonded centrosymmetric dimer in the solid-state, in a conformation appropriate for the desired binding of carboxylates. The thioureas show good discrimination between different amino acids and those thioureas incorporating chiral moieties show moderate enantioselectivity for a range of amino acid derivatives.

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