Synthesis of Six New Transition Metal Complexes: Structural Characterization and in vitro α‐Glucosidase Inhibitions Studies

Abstract Three one‐pot reactions leading to six new transition metal complexes are presented. The one‐pot reactions involved transformations of 2‐(N’‐dicyanomethylene‐hydrazino)‐benzoic acid ( DHB ) into three new ligands (Lig‐I) 2− , (Lig‐II) 2− , and (Lig‐III) 2− . The complex [Ni 2 ( Lig‐I ) 2 ] ⋅ 3H 2 O ( 1 ) was prepared in a one‐pot synthesis in which ligand, (Lig‐I) 2− was formed by the amination of DHB resulting from the nucleophilic attack of an amino group of ethylenediamine ( en ). The complex [Cu( Lig‐II )( en )(H 2 O)] ( 2 ) was prepared in a one‐pot synthesis in which ligand, ( Lig‐II ) 2− was formed by the nucleophilic attack of an amino group of en resulting in an imidazole ring formation. The dinunclear complexes [Zn 2 ( Lig‐III ) 2 (CH 3 OH) 2 ] ( 3 ) and [Cu 2 ( Lig‐III ) 2 (CH 3 OH) 2 ] ( 4 ), a linear trinuclear complex [Ni 3 ( Lig‐III )( en ) 2 (CH 3 OH)] ( 5 ), and a mononuclear complex [Mn( Lig‐III )(CH 3 OH) 4 ] ( 6 ) were synthesized using a preparation involving conversion of one of the nitriles on DHB into an imino‐ester. The resulting complexes were characterized using a variety of analytical techniques including infra‐red and UV‐vis spectroscopy, elemental analysis, and single‐crystal X‐ray diffraction analysis. The complexes displayed α‐glucosidase enzyme inhibition with IC 50 values in the range of 1.57–207 μ M.