Metal complexes of cyclic hydroxamates. Synthesis and crystal structures of 3-hydroxy-2-methyl-3H-quinazolin-4-one (ChaH) and of its Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) complexes

► The most detailed investigation to date of cyclic hydroxamate complexes. ► Important in view of the physiological relevance of cyclic hydroxamic acids. ►Crystal structures of 5 metal complexes of a cyclic hydroxamate reported. ► Structures rationalised in terms of the metal ion coordination requirements. ► Lower pKa and lower stability constants compared to acyclic hydroxamates.