New Titanium and Nickel Gallophosphates with Layered Structures

Molecular gallosilicates and their group 4 multimetallic derivatives

Reaction between the silanediol (HO)(2)Si(OtBu)(2) and gallium amides, LGaCl(NHtBu) and LGa(NHEt)(2) (L = [HC{C(Me)N(Ar)}(2)](-), Ar = 2,6-iPr(2)C(6)H(3)), respectively, resulted in the facile isolation of molecular gallosilicates LGaCl(μ-O)Si(OH)(OtBu)(2) (1) and LGa(NHEt)(μ-O)Si(OH)(OtBu)(2) (2). Compound 2 easily reacts with 1 equiv of water to form the unique gallosilicate-hydroxide LGa(OH·THF)(μ-O)Si(OH)(OtBu)(2) (3). Compounds 1-3 contain the simple Ga-O-SiO(3) framework and are the first structurally authenticated molecular gallosilicates. These compounds may be used not only as models for gallosilicate-based materials but also as further reagents because of the presence of reactive functional groups attached to both gallium and silicon atoms. Accordingly, seven molecular heterometallic compounds were obtained from the reactions between compound 3 and group 4 amides M(NMe(2))(4) (M = Ti, Zr) or M(NEt(2))(4) (M = Ti, Zr, Hf). Hence, by tuning the reactions conditions and stoichiometries, it was possible to isolate and structurally characterize the complete 1:1 and 2:1 series (4-10). Completely inorganic cores of types M-O-Ga-O-Si-O and spiro M[O-Ga-O-Si-O](2) were obtained and characterized by common spectroscopic techniques.

Potassium nickel(II) gallium phosphate hydrate, K[NiGa(2)(PO(4))(3)(H(2)O)(2)]

The title compound, potassium nickel(II) digallium tris­(phosphate) dihydrate, K[NiGa₂(PO₄)₃(H₂O)₂], was synthesized hydro­thermally. The structure is constructed from distorted trans-NiO₄(H₂O)₂ octa­hedra linked through vertices and edges to GaO₅ trigonal bipyramids and PO₄ tetra­hedra, forming a three-dimensional framework of formula [NiGa₂(PO₄)₃(H₂O)₂]⁻. The K, Ni and one P atom lie on special positions (Wyckoff position 4e, site symmetry 2). There are two sets of channels within the framework, one running parallel to the [10] direction and the other parallel to [001]. These inter­sect, forming a three-dimensional pore network in which the water mol­ecules coordinated to the Ni atoms and the K⁺ ions required to charge balance the framework reside. The K⁺ ions lie in a highly distorted environment surrounded by ten O atoms, six of which are closer than 3.1Å. The coordinated water mol­ecules are within hydrogen-bonding distance to O atoms of bridging Ga—O—P groups.

Old materials with new tricks: multifunctional open-framework materials

The literature on open-framework materials has shown numerous examples of porous solids with additional structural, chemical, or physical properties. These materials show promise for applications ranging from sensing, catalysis and separation to multifunctional materials. This critical review provides an up-to-date survey to this new generation of multifunctional open-framework solids. For this, a detailed revision of the different examples so far reported will be presented, classified into five different sections: magnetic, chiral, conducting, optical, and labile open-frameworks for sensing applications. (413 references.)

Topotactic Oxidation of TiGaPO-1, a Pyridine-Templated Titanium Gallophosphate with a New Octahedral-Tetrahedral 3-D Framework Structure Containing TiIII/TiIV

The first 3-D open-framework TiGaPO complex, constructed from Ti(III)O(6), Ti(IV)O(6), GaO(4), and PO(4) polyhedra, contains pyridinium cations in a 1-D pore network and can be oxidized in air at 543 K with retention of the original framework structure.