The crystal and molecular structures of the blood cell labelling agents tris(2-hydroxy-2,4,6-cycloheptatrien-1-onato-O,O′)indium(III) and trans-{tris(4- iso-propyl-2-hydroxy-2,4,6-cycloheptatrien-1-onato-O,O′)indium(III)}

Abstract

X-ray crystal structure analyses of tris chelate complexes of In(III) with tropolone [InT 3] and 4- iso-propyltropoloe [In(4iT) 3] show them to be monomeric with, in each case, three bidentate ligands bonded to a central metal atom. The coordination polyhedra are intermediate between trigonal prismatic and trigonal antiprismatic; mean twist angles: InT 3, 36.4°; In(4iT) 3, 36.6°. The structural features of InT 3 (which is routinely used as a blood cell labelling agent) and In(4iT) 3 (which has been investigated for labelling properties) are discussed in terms of their solution chemistry.