Layered Double Hydroxides of the Hydrocalumite-type Intercalated by the Anionic Forms Transition Metal Ion-Amino Acid Complexes – Syntheses, Characterization and Catalytic Applications
2Department of Applied and Environmental Chemistry Chemistry, University of Szeged, Szeged
3Department of Inorganic and Analytical Chemistry Chemistry, Pal Sipos, Szeged
Our recent activities in the synthesis and catalytic applications of pristine CaAl- and transition metal ion-amino acid complex intercalated CaAl-layered double hydroxides (LDHs) are described.
LDHs, because of their relative ease of synthesis, represent inexpensive, versatile, and potentially recyclable source of a variety of catalyst supports, catalyst precursors or actual catalysts. Hydrocalumite is a subgroup of LDHs. The name giving mineral has brucite-like main layers, which contain ordered arrangements of Ca2+ and Al3+ or other trivalent ions, seven- and six-coordinated, respectively, in a fixed ratio of 2:1. The layers are positively charged, which is compensated by interlayer anions, exchangeable with more or less difficulties.
During our experimental work, host-guest composites were made, where the host was Ca(II)Al(III)-LDH. The guests were Mn(II)- Cu(II)-, Ni(II)- Fe(III)-amino acid (L-cysteine, L-histidine and L-tyrosine) complex anions. They were intercalated into the CaAl-LDH.
The obtained materials were characterized by a range of methods including scanning and transmission electron microscopies, energy-dispersive X-ray analysis, X-ray diffractometry, mid- and far-range infrared, EPR and X-ray absorption spectroscopies, thermal analysis and classical analytical methods.
The intercalated metal-amino acid complexes proved to be active and selective in the epoxidation reaction with peracetic acid, and cis-diol formation when the oxidant was the in situ formed iodosyl benzene. Each complex anion-containing composite exhibited excellent recycling abilities.
Powered by Eventact EMS