Two-Dimensional Hybrid Germanium Zeotype Formed by Selective Coordination of the <i>trans</i>-1,2-Diaminocyclohexane Isomer to the Ge Atom: Heterogeneous Acid−Base Bifunctional Catalyst

[C6H10(NH2)2Ge3O6] ICMM9 is a two-dimensional germanate in which the metallic atoms are covalently bonded to chelating diamines. Its layered structure having some similitude with that of the pyroxene mineral, presents a totally new topology with two 4-c nodes. The solvothermal synthesis reaction allows the separation in situ of the two 1,2-diaminocyclohexane isomers by selective coordination of the trans isomer to octahedral Ge atoms of the ICMM9 framework. This material behaves as an active and selective heterogeneous acid−base bifunctional catalyst.