Where zeolites and oxides merge: semi-condensed tetrahedral frameworks

Syntheses and Structures of Acetyl‐Acetonato‐Alumo‐Diphenylsilanolates with Magnesium(II), Iron(II), Iron(III), Cobalt(II), and Nickel(II)

“…The course of the reaction turns out to be completely different when in the place of the bis(acetyl-acetonate) dihydrate, Ni(acac) 2 (H 2 O) 2 , the water free compound is used, as may be deduced from Equation (2 4 (OH) 2 O-(OH 2 )·OEt 2 are obtained after concentration of the solution and addition of diethyl ether. As may be deduced from the atom count in the product compared to the starting materials, not considering the solvent molecules in the crystals, the starting materials recombine without any loss of molecular entities.…”

“…The product from the reaction of water-free Ni(acac) 2 2 and is a 2:1 mixture of the two starting materials. As may be deduced from Figure 3 and Figure 4 the acetylacetonate (acac) ligands were redistributed over the metal atoms: three acac groups form chelating ligands at atoms Al1, Al2, and Al3, 4 macrocycle and the two OH groups at Al1 and Al2 have survived in the reaction, whereas the OH groups at Al3 and Al4 have condensed to an oxygen atom O3 liberating a water molecule (O4), which is coordinated at nickel atom Ni2.…”

“…The four compounds [(acac) 2 2 (M = Mg, Fe, Co and Ni) crystallize in the centro-symmetric monoclinic space group C2/c with four molecules per unit cell and are isotypic. [21] They all have a crystallographic twofold axis running through the center of the molecule with the divalent metal atoms and the two oxygen atoms of the water molecules sitting on these axes.…”

“…The tetrameric alumosiloxane [1] [O-Ph 2 Si-O-SiPh 2 -O] 4 Al 4 -(OH) 4 , which we first described in 1997, can be considered as a molecular counterpart of alumosilicates, [2] which have found a wide range of applications. [3][4][5][6] In contrast to the naturally occurring zeolites, in which each AlO 4 tetrahedron is separated by SiO 4 tetrahedra, in [O-Ph 2 Si-O-SiPh 2 -O] 4 Al 4 (OH) 4 , the four AlO 4 tetrahedra are connected through oxygen corners, thus hurting the Loewenstein rule.…”

Caracterização e análise estrutural da hidroxisodalita sintetizada a partir de amostras de solo amazônico

“…Material de partida como rejeito industrial do processo de benefi ciamento de caulim, de indústrias da região [7]. A e B são espécies capazes de formar tetraedros (Al e Si) e X pode ser uma variedade de ânions mono e divalentes.…”