New Metal-Organic Systems With A Functionalized Oxamate-Type Ligand And Mn-Ii, Fe-Ii, Cu-Ii And Zn-Ii (Vol 30, Pg 2413, 2019)

Four new complexes of formula [Fe(H(2)pcpa)(2)(H2O)(2)] (1), {[Mn(Hpcpa)(H2O)(3)]center dot 1/2H(2)O}(n) (2), {[Zn(Hpcpa)(H2O)(3)]center dot 1/2H(2)O}(n) (3) and [Cu-2(Hpcpa)(2)(bipy)(2)]center dot 8H(2)O (4) [H(3)pcpa = N-(4-carboxyphenyl)oxamic acid; bipy = 2,2'-bipyridine] have been synthesized and their structures determined by X-ray diffraction. The structure of 1 consists of mononuclear iron(II) units where each iron(II) ion is six-coordinate by two trans-positioned water molecules and two bidentate H(2)pcpa(-) ligands building a distorted octahedral environment. 2 and 3 consist of neutral zigzag chains of Mn-II and Zn-II ions respectively, the Hpcpa(2-) groups acting as linkers in a bidentate/monodentate coordination mode with three mer-positioned water molecules achieving the six-coordination around the metal centers. Compound 4 is a neutral centrosymmetric dicopper(II) complex where two Hpcpa(2-) groups adopting the bidentate/monodentate coordination mode and act as bridges and bidentate bipy molecules act as end-cap ligands, describing a square pyramidal surrounding around each copper atom. Cryomagnetic measurements for 1, 2 and 4 in the temperature range 1.9-300 K reveal the occurrence of a field-induced single-ion magnet (SIM) behavior (1) and weak interchain (J = -0.22 cm(-1) , 2) and intradimer (J = -0.39 cm(-1) , 4) antiferromagnetic interactions, the Hamiltonian being defined as H =-J S-a.S-b.