Design of complex–ligand systems based on thiouracil. A novel cyclic tetramer of cobalt( III ) with 1-(2-thiouracil-4-methylene)-3,6-diazahexane

A Schiff base derived from 2-thiouracil-4-aldehyde and dien reacts with CoII(CF3SO3)2 to afford a novel cyclic tetramer of cobalt(III) by self-assembly; the complex has a columnar cavity at its centre with an effective diameter of ca. 1.8 Å.