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The occurrence of a slow relaxation of the magnetization in a one-dimensional (1D) system was recently reported by one of us.[1] The system was claimed to illustrate, for the first time, a theoretical model designed by Glauber in 1963 for anisotropic Ising systems [2] and opened the perspective of a potential use of 1D magnetic molecular nanowires for information storage. Even though 1D magnetism is a very active area of research, such dynamic behavior was never detected before since it is not clear how to fulfill experimentally the requirements of a perfect 1D Ising-type chain. This finding prompted us to look carefully at 1D systems containing anisotropic elements, such as cobalt(ii) and low-spin iron(iii) centers that we synthesized recently, [3] to investigate their anisotropic magnetic properties and to study the dynamics of their magnetization.The stable low-spin cyanide-containing iron(iii) precur-À (L = bidentate nitrogen donor) react with hydrated metal ions in aqueous solution [4,5] and afford single crystals of the bimetallic double zigzag chains [{Fe(1 with L = 2,2'-bipyridine (bpy) and 2 with L = 1,10-phenanthroline (phen)). We found that 1 and 2 show intrachain ferromagnetic coupling, 1D Ising-type behavior, slow relaxation of the magnetization, and hysteresis effects and thus are the second examples of anisotropic molecular magnetic nanowires and the first with an intrachain ferromagnetic coupling. Their preparation, Xray crystal structure, [6] and preliminary static and dynamic magnetism are reported herein.Compounds 1 and 2 are isostructural (monoclinic system, space group P2 1 /n). They are made up of neutral cyanidebridged Co II

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A novel isoreticular oxamato-based manganese(II)-copper(II) open metal-organic framework H(2)O@iso1 featuring a pillared square/octagonal layer structure with alternating open and closed octagonal pores has been rationally prepared. The open-framework topology is responsible for a large selectivity in the separation of small gas (CO(2) over CH(4)) and vapor molecules (CH(3)OH over CH(3)CN and CH(3)CH(2)OH). H(2)O@iso1 displays a long-range three-dimensional ferromagnetic ordering with a drastic variation of the critical temperature as a function of the guest molecule [T(C) < 2.0 K (CO(2)@iso1 and CH(4)@iso1) and T(C) = 6.5 (CH(3)OH@iso1) and 21.0 K (H(2)O@iso1)].

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The preparation, X-ray crystallography and magnetic investigation of the compounds PPh4[Cr(bipy)(CN)4].2 CH3CN.H2O (1) (mononuclear), [[Cr(bipy)(CN)4]2Mn-(H2O)4].4H2O (2) (trinuclear), [[Cr(bipy)(CN)4]2Mn(H2O)2] (3) (chain) and [[Cr(bipy)(CN)4]2Mn(H2O)].H2O.CH3CN (4) (double chain) [bipy=2,2'-bipyridine; PPh4 (+)=tetraphenylphosphonium] are described herein. The [Cr(bipy)(CN)4]- unit act either as a monodentate (2) or bis-monodentate (3) ligand toward the manganese atom through one (2) or two (3) of its four cyanide groups. The manganese atom is six-coordinate with two (2) or four (3) cyanide nitrogens and four (2) or two (3) water molecules building a distorted octahedral environment. In 4, two chains of 3 are pillared through interchain Mn-N-C-Cr links which replace one of the two trans-coordinated water molecules at the manganese atom to afford a double chain structure where bis- and tris-monodenate coordination modes of [Cr(bipy)(CN)4]- coexist. The magnetic properties of 1-4 were investigated in the temperature range 1.9-300 K. A Curie law behaviour for a magnetically isolated spin quartet is observed for 1. A significant antiferromagnetic interaction between CrIII and MnII through the single cyanide bridge [J=-6.2 cm(-1), the Hamiltonian being defined as H=-J(SCr1.SMn+SCr2.SMn] occurs in 2 leading to a low-lying spin doublet which is fully populated at T <5 K. A metamagnetic behaviour is observed for 3 and 4 [the values of the critical field Hc being ca. 3000 (3) and 1500 Oe (4)] which is associated to the occurrence of weak interchain antiferromagnetic interactions between ferrimagnetic Cr2III MnII chains. The analysis of the exchange pathways in 2-4 through DFT type calculations together with the magnetic bevaviour simulation using the quantum Monte Carlo methodology provided a good understanding of their magnetic properties.

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