Heterostructures patterned on aluminosilicate microporous substrates: Crystallization of cobalt(III) tris(N,N-diethyldithiocarbamato) on the surface of a HEU-type zeolite

Abstract The treatment of a NaHEU zeolite with concentrated Co(CH 3 COO) 2 solutions at 100 °C, results in the corresponding CoHEU zeolite (7.5 wt.% Co) which is pale-rose to brown in color. This Co-loaded microporous material is characterized by the presence of an amorphous surface-supported “layer”, consisting most probably of hydrated Co(III)-hydroxides and/or -oxyhydroxides. The interaction of CoHEU with aqueous solution of NaS 2 CN(C 2 H 5 ) 2 , results in the crystallization of Co[S 2 CN(C 2 H 5 ) 2 ] 3 onto the zeolite surface. The characterization of CoHEU-Et 2 dtc was performed using a combination of microscopic (SEM–EDS, TMAFM), spectroscopic (DR(UV–Vis)S, FT-IR, XPS, 29 Si & 27 Al MAS–NMR), and diffraction (PXRD) techniques. The stability of the material in different solvents was examined using 60 Co labeled samples and γ-ray spectrometry. The submicron deep-green to black crystals of the complex compound, could be topotactically developed within the precursor “layer” through nucleophilic substitution by Et 2 dtc − ligands. Thus the Co(III)(Et 2 dtc) 3 heterostructure may be anchored on the zeolitic substrate by unlocalized intermolecular forces (e.g. electrostatic interactions, hydrogen bonds or van der Waals forces). Moreover, the (0 0 1) surface of the tabular monoclinic Co[S 2 CN(C 2 H 5 ) 2 ] 3 crystals could possibly be involved in lattice-mismatched heteroepitaxial phenomena, on the (0 1 0) surface of the platy monoclinic HEU-type zeolite crystals, without affecting the aluminosilicate framework.