Schiff Base Heterometallic Complexes and Their Potential Applications

High Resolution Image Download MS PowerPoint Slide A Schiff base ligand, H 2 L, with two distinct compartments to accommodate a transition and an alkaline earth metal ion was used to synthesize two monometallic, [CuL(H 2 O)(CH 3 OH)] ( 1 ) and [NiL(H 2 O)] ( 2 ), and six heterometallic complexes, [CuCaL(NO 3 ) 2 ] ( 3 ), [CuSrL(NO 3 ) 2 ] ( 4 ), [CuBaL(NO 3 ) 2 ](H 2 O) ( 5 ), [NiCaL(NO 3 ) 2 ] ( 6 ), [NiSrL(NO 3 ) 2 ] ( 7 ), and [NiBaL(NO 3 ) 2 ] ( 8 ), which were characterized by single crystal X-ray diffraction. Their potential as single-source precursors (SSPs) and their antibacterial properties were investigated. After annealing at 1000 °C in air for 1 h, the complexes ( 3 ), ( 4 ), ( 7 ), and ( 8 ) formed the following mixed metal oxides (MMOs): Ca 2 CuO 3 for ( 3 ), CuSrO 2 and CuSr 2 O 3 for ( 4 ), Ni 6.64 Sr 9 O 21 and Ni 2 Sr 4 O 9 for ( 7 ), and Ni 5 Ba 6 O 15 for ( 8 ). The mixture of two heterobimetallic complexes ( 3 ) and ( 4 ), ( 3 ) and ( 7 ), and ( 4 ) and ( 6 ) allowed the formation of MMOs containing three different metal ions, such as CuCa 1.50 Sr 0.50 O 3, CuCa 0.38 Sr 0.62 O 2, and CaCuSrO 3 . The scanning electron microscopy (SEM) study revealed a sponge-like structure for all the obtained MMOs. The six heterobimetallic complexes showed good solubility in MeOH, DMF, and DMSO. With regard to the antibacterial properties, the protonated ligand and monometallic complex of copper(II) showed a zone of inhibition (ZOI) that was twice the size of the tested heterobimetallic complexes.