Synthesis, crystal structures, and magnetic properties of two heterobinuclear complexes with a dissymmetrical oxamidate ligand

Two heterobimetallic compounds {[CuLMn(H2O)3 · 1.75H2O]2}n (I) and {[CuLCo(H2O)3 · 2H2O]2}n (II) (H4L = N-(2,5-dicarboxyl phenyl)-N′-(2-amino propyl)oxamide) have been synthesized and characterized by IR, elemental analysis, single-crystal X-ray diffraction, and magnetic properties. They crystallize in the triclinic system with space group \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$P\bar 1$\end{document}. The structures of the complexes consist of neutral tetranuclear units formed through syn-anti carboxylate bridges in ladder-like chains. The magnetic properties of complexes I and II indicated antiferromagnetic interaction between the metal ions.