Synthesis, crystal structure and thermal properties of Ca6(C12H14O4)4(CO3)(OH)2(H2O)x--a 3D inorganic hybrid material.

The inorganic-organic compound Ca(6)(1,3-adamantanedicarboxylate)(4)(CO(3))(OH)(2)(H(2)O)(x) with 0 < x < 15.2 was synthesized by hydrothermal methods. The crystal structure was determined on the basis of high resolution synchrotron powder diffraction data and poly-crystal measurements. The crystal structure of Ca(6)(C(12)H(14)O(4))(4)(CO(3))(OH)(2)(H(2)O)(14) is tetragonal, space group I4(1)/amd (141) with a = 29.12 Å, c = 15.85 Å, V = 13,440 Å(3) and Z = 8. The compound is classified as a 3D inorganic hybrid material with a 3-dimensional inorganic framework consisting of Ca and O, connected to 1,3-adamantanedicarboxylate anions. The structure shows hydrophilic channels in a diamond-like network. In between the channels there exist hydrophobic pores with surfaces defined by adamantane cages. The shortest distance between hydrogen atoms from different molecules in these pores is 3.6 Å. The largest hydrophilic cavity has a diameter of 10 Å and the pores connecting the channels have a diameter of 5 Å. In the as-synthesised state these channels are filled with water molecules. Reversible dehydration-rehydration occurs. The dehydrated compound easily takes up water from ambient air.

Design, synthesis and characterization of a Pt-Gd metal-organic framework containing potentially catalytically active sites.

The heterobimetallic metal-organic framework {[(BPDC)PtCl(2)](3)(Gd(H(2)O)(3))(2)}.5H(2)O (BPDC = 2,2'-bipyridine-5,5'-dicarboxylate) has been designed and synthesized by hydrothermal methods. The new coordination polymer contains subunits of (BPDC)PtCl(2) (1) where both N atoms of the BPDC ligand are attached to a square-planar Pt(II) center. The two remaining cis coordination sites at Pt(II) are occupied by chloride ions. The final structure (2) of the polymeric network is obtained when Gd(III) ions link together the (BPDC)PtCl(2) units, which are organized in sheets, into larger blocks. These blocks are stacked along the crystallographic [010] direction and are held together by a hydrogen bonding scheme that involves carboxylate oxygen atoms and water molecules in the coordination sphere of Gd. The coordination polymer 2 can be obtained in a single-step reaction or in a two-step synthesis where the corresponding Pt complex (1) was first synthesized followed by reacting 1 with Gd(NO(3))(3).6H(2)O. In situ high temperature powder X-ray diffraction shows that the crystalline coordination polymer transforms into an anhydrous modification at 100 degrees C. This modification is stable to 350 degrees C, at which temperature the structure starts to decompose. The coordination sphere around platinum in the polymer closely resembles organometallic Pt complexes that have been previously found to catalytically or stoichiometrically activate and functionalize hydrocarbon C-H bonds in homogeneous systems.

Design of novel bilayer compounds of the CPO-8 type containing 1D channels.

The reaction between Zn(NO3)2.6H2O and 5-aminoisophthalic acid (aip) in a mixture of diethylformamide (DEF) and ethanol resulted in [Zn(C8H5NO4)(C5H11NO)]n (CPO-8-DEF). This compound is composed of infinite 2D layers with tetrahedral Zn atoms and aip ligands in a triangular topology. The DEF molecules are bonded to Zn, and within each layer, the DEF molecules are oriented in the same direction, while in the subsequent layer, the DEF molecules are oriented in the opposite direction. By introduction of the pillaring ligands 4,4-bipyridine (BPY), 1,2-di-4-pyridylethylene (DPE), 1,2-di-4-pyridylethane (DPA), and 1,3-di-4-pyridylpropane (DPP) into mixtures of N,N'-dimethylformamide and water with Zn(NO3)2 and aip, we have successfully synthesized a series of related pillared bilayer compounds with the same common triangular Zn(aip) layer structural motif as that observed in CPO-8-DEF. The compounds are denoted as CPO-8-BPY ([Zn(C8H5NO4)(C10H8N2)(0.5)]n.3nH2O), CPO-8-DPE ([Zn(C8H5NO4)(C12H10N2)(0.5)]n.2.5nH2O), CPO-8-DPA ([Zn(C8H5NO4)(C12H12N2)(0.5)]n.2.5nH2O), and CPO-8-DPP ([Zn(C8H5NO4)(C13H14N2)(0.5)]n.3nH2O). In all cases, the pillars create spaces inside the bilayers that result in 1D channels running along the [010] directions with dimensions of 3.5 x 6.7 A(2). These channels contain water molecules that can be removed on heating to 150 degrees C, resulting in porous structures. The crystal structures of these porous high-temperature variants have been determined on the basis of powder X-ray diffraction data. All of the compounds show preferential adsorption of H2 over N2 at 77 K.