Synthesis, Structure and Magnetic Properties of a Series of Novel Isophthalate‐Bridged Manganese(II) Polymers with Double‐Layer or Double‐Chain Structures

Abstract

AbstractFour isophthalate‐bridged manganese(II) coordination polymers, [Mn4(ip)4(H2O)2(Him)4]n (1), [Mn(ip)(Him)2]n (2), [Mn(ip)(dpe)]n·0.5ndpe·nH2O (3) and [Mn2(ip)2(bpy)2]n (4) [ip = isophthalate, Him = imidazole, bpy = 2,2′‐bipyridine and dpe = (E)‐1,2‐bis(4‐pyridyl)ethene], have been rationally synthesized and characterized by single‐crystal X‐ray structure determinations and magnetic studies. Both 1 and 3 are two‐dimensional (2D) double‐layer polymers. In 1, novel Mn4 entities are linked by ip ligands, while 3 is made of [Mn(ip)]n parallel double chains cross‐linked by the μ‐dpe ligands. Both 2 and 4 are one‐dimensional (1D) double‐chain polymers, where 2 is composed of [Mn(ip)]n parallel double chains capped by the Him ligands, while 4 is made of [Mn2(ip)2]n helical double chains capped by the chelating bpy ligands. Variable‐temperature magnetic susceptibility measurements revealed weak antiferromagnetic exchange interactions between the adjacent MnII ions of the four coordination polymers. The data of 2−4 were fitted to the homonuclear alternating chain model to give magnetic coupling parameters of J1 = −0.71(4) to −1.01(3) cm−1 and J2 = −0.02(2) to −0.46(2) cm−1. In the case of 1, the fitting of magnetic data considering only the interactions within the Mn4 moiety led to J = −2.17(1) cm−1 and zJ′ = −0.01(5) cm−1, using a combination of a dimeric model and a mean molecular field approximation model. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)