Metal Complexes of Cyanoethyl Derivative of a Macrocyclic Chelator: Synthesis, Characterization and Antimicrobial Investigation

Interaction of tet-a (an isomeric ligand of Me₆[14]ane) with an excess of acrylonitrile yielded an N-pendent derivative, tet-ax in which two cyanoethyl groups were attached on less crowded two trans-N atoms. Reactions of nickel(II) acetate tetrahydrate followed by subsequent addition of NaClO₄·6H₂O, copper(II) perchlorate hexahydrate and cobalt(II) acetate tetrahydrate followed by the addition of HCl [in case of cobalt(III) complex] with tet-ax produced four coordinated square planar orange [Ni(tet-ax)](ClO₄)₂, six coordinated octahedral red [Cu(tet-ax)(ClO₄)₂] and six coordinated green trans-[Co(tet-ax)Cl₂]Cl complex, respectively. The axial substitution reactions on [Cu(tet-ax)(ClO₄)₂] with MX (M = K/Na, X = NCS, NO₃, NO₂, Cl, Br, or I) resulted in six coordinated octahedral axial substitution products, blue [Cu(tet-ax)(NCS)(ClO₄)], [Cu(tet-ax)(NO₃)(H₂O)]ClO₄, and [Cu(tet-ax)(NO₂)(H₂O)]ClO₄, violet [Cu(tet-ax)Cl(H₂O)]ClO₄ and [Cu(tet-ax)Br(H₂O)]ClO₄ and green [Cu(tet-ax)I(H₂O)]ClO₄ respectively. All the newly formed compounds have been characterized by using different modern techniques. The antimicrobial activities of this new N-pendent derivative tet-ax and its metal complexes have been investigated against different bacteria and fungi.