Bimetallic Metal‐Organic Frameworks Containing the ${\rm [M(2,}x-{\rm pdc)^{2-}_{2}}]$ (M = Cu, Pd, Pt; x = 4, 5) Building Block – Synthesis, Structure, and Magnetic Properties

Abstract

AbstractNew bimetallic coordination polymers containing the ${\rm [Cu(2,}x-{\rm pdc)^{2-}_{2}}]$ (pdc = pyridine dicarboxylate, NC5H3(CO2)2; x = 4,5) ‘metalloligand’ unit, linked by MnII or CoII cations, have been obtained by hydrothermal synthesis. The metalloligand species K2[Cu(2,x−pdc)2(OH2)n]·mH2O (1, 2) were reacted under basic conditions with MnCl2 at 200 °C to form the compounds [CuMn(2,x−pdc)2] (3, x = 4; 4, x = 5), which are unexpectedly isostructural. Similar reaction with CoCl2 gave [Co3Cu2(2,4–pdc)4(μ4−OH)2(OH2)]2 (5), which has a ladder‐like framework based on Co‐hydroxide chains, and the 2‐dimensional sheet polymer [CoCu(2,4‐pdc)2(OH2)4] (6). A related CuII‐only chain compound, [Cu2(2,5−pdc)2(OH2)2]·4H2O (7) is also reported. The compounds 1–7 have been structurally characterized by single crystal X‐ray diffraction. The DC magnetic susceptibilites of 3–6 and [M3M′2(2,4−pdc)4(μ4−OH)2(OH2)] (8: M = Co, M′ = Pd; 9: M = Co, M′ = Pt; 10: M = Ni, M′ = Pd; 11: M = Ni, M′ = Pt) have been studied by SQUID magnetometry; 3 and 4 undergo antiferromagnetic ordering at low temperature, 5, 8 and 9 are metamagnets, 6 exhibits weak ferromagnetic exchange, while 10 and 11 show canted antiferromagnetism.