Design of metal-complex magnets. Syntheses and magnetic properties of mixed-metal assemblies {NBu4[MCr(ox)3]}x (NBu4+ = tetra(n-butyl)ammonium ion; ox2- = oxalate ion; M = Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+)
01 Dec 1992-Journal of the American Chemical Society (American Chemical Society)-Vol. 114, Iss: 18, pp 6974-6979
TL;DR: The reaction of K 3 [Cr(ox) 3 ].3H 2 O, a metal(II) salt, and tetra(n-butyl)ammonium bromide in the molar ratio of 1:1:1.5 in water at room temperature afforded a series of mixed-metal assemblies with the formula {NBu 4 [MCr(ox), 3 ]} x (M=Mn 2+, Fe 2+, Co 2+
Abstract: The reaction of K 3 [Cr(ox) 3 ].3H 2 O, a metal(II) salt, and tetra(n-butyl)ammonium bromide in the molar ratio of 1:1:1.5 in water at room temperature afforded a series of mixed-metal assemblies with the formula {NBu 4 [MCr(ox) 3 ]} x (M=Mn 2+ , Fe 2+ , Co 2+ , Ni 2+ , Cu 2+ , Zn 2+ ).
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TL;DR: In this paper, the development in the field of coordination polymers or metal-organic coordination networks, MOCNs (metal-organic frameworks, MOFs) is assessed in terms of property investigations in the areas of catalysis, chirality, conductivity, luminescence, magnetism, spin-transition (spin-crossover), nonlinear optics (NLO) and porosity or zeolitic behavior upon which potential applications could be based.
Abstract: The development in the field of coordination polymers or metal-organic coordination networks, MOCNs (metal-organic frameworks, MOFs) is assessed in terms of property investigations in the areas of catalysis, chirality, conductivity, luminescence, magnetism, spin-transition (spin-crossover), non-linear optics (NLO) and porosity or zeolitic behavior upon which potential applications could be based.
3,117 citations
TL;DR: Delamination of LDHs is an interesting route for producing positively charged thin platelets with a thickness of a few atomic layers, which can be used as nanocomposites for polymers or as building units for making new designed organic- inorganic or inorganic-inorganic nanomaterials.
Abstract: Layered double hydroxides (LDHs) are a class of ionic lamellar compounds made up of positively charged brucite-like layers with an interlayer region containing charge compensating anions and solvation molecules. Delamination of LDHs is an interesting route for producing positively charged thin platelets with a thickness of a few atomic layers, which can be used as nanocomposites for polymers or as building units for making new designed organic-inorganic or inorganic-inorganic nanomaterials. The synthesis of nanosized LDH platelets can be generally classified into two approaches, bottom-up and top-down. It requires modification of the LDH interlamellar environment and then selection of an appropriate solvent system. In DDS intercalated LDHs, the aliphatic tails of the DDS- anions exhibit a high degree of interdigitation in order to maximize guest-guest dispersive interactions. Bellezza reported that the LDH colloids can also been obtained by employing a reverse microemulsion approach.
2,616 citations
TL;DR: The diversity of magnetic exchange interactions between nearest-neighbour moment carriers is examined, covering from dimers to oligomers and their implications in infinite chains, layers and networks, having a variety of topologies.
Abstract: The purpose of this critical review is to give a representative and comprehensive overview of the arising developments in the field of magnetic metal–organic frameworks, in particular those containing cobalt(II). We examine the diversity of magnetic exchange interactions between nearest-neighbour moment carriers, covering from dimers to oligomers and discuss their implications in infinite chains, layers and networks, having a variety of topologies. We progress to the different forms of short-range magnetic ordering, giving rise to single-molecule-magnets and single-chain-magnets, to long-range ordering of two- and three-dimensional networks (323 references).
2,238 citations
TL;DR: In this paper, a room-temperature organometallic magnet was synthesized by combining a hexa-cyanometalate [M(CN)6]q− with a Lewis acid Lp+.
Abstract: THE rational design of molecular compounds that exhibit spontaneous magnetic ordering might enable one to tailor magnetic properties for specific applications in magnetic memory devices1–4. In such materials synthesized previously5–17, however, the underlying weak magnetic interactions are incapable of maintaining ordering at ambient temperatures. One remarkable exception is a compound derived from vanadium and tetracyanoethylene18, but the material is amorphous and fragile, and consequently the molecular interactions responsible for its striking properties are not understood. Here we demonstrate another route to the synthesis of a room-temperature organometallic magnet, in which we combine a hexa-cyanometalate [M(CN)6]q− with a Lewis acid Lp+ If L and M are transition-metal ions, then the orbital interactions in the resulting compound can be described by well understood principles21–24, and it is therefore possible to choose the metals to tune the compound's magnetic properties–in particular, the magnetic ordering (Curie) temperature Tc (refs 21–26). We have synthesized a room-temperature magnetic material (TC = 315 K) that belongs to the Prussian blue family of compounds27 (where M is chromium and L is vanadium), demonstrating that transition-metal hexacyano complexes are promising components for the construction of molecule-based high-Tc magnets.
1,389 citations
TL;DR: The synthesis of single crystals formed by infinite sheets of this magnetic coordination polymer interleaved with layers of conducting BEDT-TTF cations are reported, and it is shown that this molecule-based compound displays ferromagnetism and metallic conductivity.
Abstract: Crystal engineering--the planning and construction of crystalline supramolecular architectures from modular building blocks--permits the rational design of functional molecular materials that exhibit technologically useful behaviour such as conductivity and superconductivity, ferromagnetism and nonlinear optical properties. Because the presence of two cooperative properties in the same crystal lattice might result in new physical phenomena and novel applications, a particularly attractive goal is the design of molecular materials with two properties that are difficult or impossible to combine in a conventional inorganic solid with a continuous lattice. A promising strategy for creating this type of 'bi-functionality' targets hybrid organic/inorganic crystals comprising two functional sub-lattices exhibiting distinct properties. In this way, the organic pi-electron donor bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) and its derivatives, which form the basis of most known molecular conductors and superconductors, have been combined with molecular magnetic anions, yielding predominantly materials with conventional semiconducting or conducting properties, but also systems that are both superconducting and paramagnetic. But interesting bulk magnetic properties fail to develop, owing to the discrete nature of the inorganic anions. Another strategy for achieving cooperative magnetism involves insertion of functional bulky cations into a polymeric magnetic anion, such as the bimetallic oxalato complex [MnIICrIII(C2O4)3]-, but only insoluble powders have been obtained in most cases. Here we report the synthesis of single crystals formed by infinite sheets of this magnetic coordination polymer interleaved with layers of conducting BEDT-TTF cations, and show that this molecule-based compound displays ferromagnetism and metallic conductivity.
1,198 citations