Formation of a narrow chiral cavity in bis-copper(ii) complexes of ferrocenylmethyl-l-tyrosine and its interaction with achiral guests.

Earlier we reported the tendency of ferrocenylmethyl substituted amino acids to organize around Cu(ii) in a C(2) symmetry. In this paper we have utilized this property to form a chiral cavity using a l-tyrosine derivative. Structural characterization of [Cu(II)(S-fTyr)(2)(MeCN)(2)] (), where S-fTyr(1-) is ferrocenylmethyl-l-tyrosinate, showed that the alignment of two tyrosine aromatic rings around the fifth coordination site generates a narrow cavity. Structural characterization of [Cu(S-fTyr)(2)(pyrazine)] (), [Cu(S-fTyr)(2)(pyridine)] (), [Cu(S-fTyr)(2)(bpy)] () and [Cu(S-fTyr)(2)(H(2)O)] () revealed that planar heterocyclic N-donors as guests stabilized the cavity, while polar water molecules destroyed it. Electrochemical properties of the complexes showed a shift of Cu(II)/Cu(I) potentials depending on the strength of the guest binding inside the cavity.