Metal-anion framework

Bochkarev et al. 16 prepared hyperbranched dendrimers via polymerization of tris(pentafluorophenyl)germanium anions resulting in branched macromolecules with Ge-branching centers. Building block propagation was attributed to metal anion, aromatic substitution of a phenyl, para-fluoro-moiety. Thus, treatment of Ge-monomer 8 with excess Ge-anion afforded hyperbranched macromolecules with an internal framework resembling tetrakisGedendrimer 9 (Scheme 8.4). Subsequently, Sn and Si were employed for hyperbranched dendrimer construction. 

Magnetite (FC3O4) is a component of the water-gas shift reaction that crystallizes to the inverse spinel structure. The general formula of the oxides known as spinel is AB204. In the normal spinel-type structure, A is an A2+ metal, and B is a B3+ metal. O2- forms a CCP anionic framework, where the A atoms occupy 1/8 of the tetrahedral sites and the B atoms occupy 1/2 of the octahedral sites (see Figures 1.6 and 1.7). An example of a normal spinel is Mg A1204. 

Organically templated 3d-4f mixed metal sulfates of the formula [C2N2H10][La2M(H2O)2(SO4)6] (M = Co, Ni), have been recently synthesized by Clearfield et alP The three-dimensional anionic framework is formed by the bridging of La(lli) and divalent transition metal ions by the sulfate anions. 8-Membered ring tunnels run along the c-axis, which are occupied by the protonated organic cations. 

Custelcean R, Moyer BA, Bryantsev VS et al (2006) Anion coordination in metal-organic frameworks functionalized with urea hydrogen-bonding groups. Cryst Growth Des 6 555-563... 

Custelcean R, Haverlock TJ, Moyer BA (2006) Anion separation by selective crystallization of metal-organic frameworks. Inorg Chem 45 6446-6452... 

Custelcean R, Moyer BA (2007) Anion separation with metal-organic frameworks. Eur J Inorg Chem 1321-1340... 

Rottgers and Sheldrick have recently reported that l,10-dithia-18-crown-6 1 formed lamellar coordination polymer with Cul and ion-ligating iodocuprate(i) based on two-dimensional coordination networks with Cul and alkali metal cations <2000MI271>. Both anionic frameworks contain characteristic iodocuprate(l) chains that are bridged in a /r-Sl,S10 manner by 1. However, the structure-directing influence of the alkali metal cation manifests itself in both the connectivity pattern and the stoichiometry of the resulting Cul-based network. 

The transition metal trichalcogenides MX3 (M = Ti, Zr, Hf, Nb, Ta X = S, Se) have been studied in some detail. All the trichalcogenides contain anion-anion bonding and consequently a redox competition exists between electron transfer to the metal center and electron transfer to the anions. The situation is the converse of the deintercalation of the thallium vanadium sulfides, where the competition is between oxidation of T1+ cations and that of the metal sulfur framework. 

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