Heterobimetallic complexes of Mo–μ-O–M (M = Ca, Sr, Ba) with alkaline earth metals based on a flexible dentate (Me3tacn)MoO3 unit as a metalloligand

Abstract

In this paper, we discussed the connection characteristics of the neutral weak donor metalloligand (Me3tacn)MoO3∙H2O (1) (Me3tacn = 1,4,7-trimethyl-1,4,7-triazaocynonane) and the formation of Lewis acid base adducts on the nitrates of alkaline-earth metals. Five heterobimetallic complexes {η1-(Me3tacn)MoO3}Ca(η2-NO3)2(H2O)3 (2), [{η1-(Me3tacn)MoO3}Ca(η2-NO3)2{η2,μ2-(Me3tacn)MoO3}]2 (3), {η1-(Me3tacn)MoO3}4Ca(η2-NO3)2∙12H2O (4), [{η2,μ2-(Me3tacn)MoO3}Sr(H2O)6]2Cl4∙2H2O (5), and {η2-(Me3tacn)MoO3}4Ba(η2-NO3)2∙8H2O (6) were synthesized and the crystal structures of the complexes were determined by X-ray crystallography. It is found that the (Me3tacn)MoO3 metalloligand was of good connectivity and rich coordination modes. Moreover, the complexes were characterized by infrared, fluorescence and UV-vis spectroscopies. The stability of complexes 2−6 at different temperatures was analyzed by thermogravimetry, and the antibacterial activity of the complexes was explored by disk diffusion method.