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Abstract The construction of Co(II)-amino acid complexes (l -histidine, l -cysteine, l -tyrosine) among the layers of CaAl-layered double hydroxide was attempted. The stepwise intercalation (introducing the anionic form of the amino acid first, then constructing the Co(II) complex) proved to be unsuccessful, while the direct ion exchange of the anionic form of the separately prepared complex provided with the Co(II) complex intercalated substances. The success of the intercalation was verified by X-ray diffractometry. The resulting composite materials were structurally characterized by a range of instrumental methods like UV–vis, inductively coupled plasma–optical emission, mid-range as well as far infrared spectroscopies and scanning electron microscopy. Highlights • Attempted intercalation of Co(II)-amino acid complexes among the layers of CaAl-LDH. • Successful intercalation was achieved using the anionic forms of the separately prepared complexes. • Verification by powder X-ray diffractometry. • Mapping the possible coordination sites with classical and instrumental methods. [ABSTRACT FROM AUTHOR]

Host-guest composite materials were prepared applying the anionic forms of Ni(II)-amino acid ( l-histidine, l-cysteine, and l-tyrosine) as the guests and CaAl-layered double hydroxide (CaAl-LDH) as the host. The syntheses were performed either by introducing the amino acid anions first and then constructing the metal ion-amino acid complexes or intercalating the pre-prepared complexes in anionic forms. The pristine as well as the composite LDH samples were structurally characterized by X-ray diffractometry, mid IR spectroscopy and scanning electron microscopy. The structural features of the interlayer complexes were studied by UV-Vis, inductively coupled plasma optical emission, mid and far IR and X-ray absorption spectroscopies as well as energy-dispersed X-ray analysis. On the basis of the acquired data, structural models were constructed. The composites were applied as catalysts in the liquid-phase oxidation of cyclohexene applying peracetic acid and the in situ formed iodosyl benzene as oxidants. Using peracetic acid afforded epoxide, while applying iodosyl benzene provided cis diol as the major or exclusive oxidation product. The catalysts displayed good recycling properties. [ABSTRACT FROM AUTHOR]

Intercalated composite materials were prepared with CaAl-layered double hydroxide as host and Cu(II)-amino acid ( l -cysteine, l -histidine and l -tyrosine) complex anions as guests. Two methods (intercalation of the ligand first followed by constructing the complex; preforming the complex first, then introducing it among the layers of the host) and optimization of the synthesis conditions were performed to obtain composites having the complex exclusively among the layers. The composite materials were structurally characterized by powder X-ray diffractometry, mid infrared (IR) spectroscopy with ATR (attenuated total reflectance) or photoacoustic detections, transmission and scanning electron microscopies and X-ray photoelectron spectroscopy. Structural features of the intercalant (coordination number, coordination sites) were elucidated by classical chemical and energy dispersive X-ray analyses, EPR (electron paramagnetic spectroscopy), X-ray absorption and far IR spectroscopies. Structural models based on these methods are also given. Catalytic activities, selectivities and recycling abilities of the substances were studied in the oxidation reactions of cyclohexene with peracetic acid and in situ formed iodosylbenzene as oxidants in the liquid phase. The catalysts were active in the Ullmann coupling reaction as well. The intercalated substances were found to be efficient and highly selective catalysts with very good recycling abilities. [ABSTRACT FROM AUTHOR]

Intercalated composite materials were prepared with CaAl-layered double hydroxide as the host and Mn(II)–amino acid ( l -cysteine, l -histidine and l -tyrosine) complex anions as the guest. Two methods (intercalation of the ligand first followed by constructing the complex; preforming the complex first, then introducing it among the layers of the host) and optimization of the auxiliary conditions were performed to arrive at composites having the complex exclusively among the layers. The obtained substances were structurally characterized by powder X-ray diffractometry, mid IR spectroscopy in diffuse reflectance mode and with ATR or photoacoustic detections, and scanning electron microscopy. The structural features of the intercalant (coordination number, coordination sites) were elucidated by classical chemical and energy dispersive X-ray analyses, EPR, X-ray absorption and far IR spectroscopies. Structural models are also given. The catalytic activities, selectivities and recycling abilities of the substances were studied in the oxidation reactions of cyclohexene with peracetic acid and in situ formed iodosylbenzene as oxidants and allylic alcohol with peracetic acid, in the liquid phase. The intercalated substances proved to be efficient and highly selective (with peracetic acid: outstanding epoxide, with iodosylbenzene superior diol selectivities) catalysts with very good recycling abilities. [ABSTRACT FROM AUTHOR]

Covalently anchored Ni(II)–C-protected amino acid ( l -histidine, l -cysteine, and l -cystine) complexes inspired by the active site of the Ni-superoxide dismutase enzyme were synthesised using chloropropylated silica gel as support. The structural features of the surface complexes were studied by the Kjeldahl method and ICP-MS, mid/far IR, UV–vis diffuse reflectance, and X-ray absorption spectroscopies. The enzyme-like activities of the materials were determined in a biochemical test reaction. Covalent grafting and building the complex onto the surface of the support were successful in all cases. It was found that in many instances the structures obtained and the coordinating groups substantially varied upon changing the conditions of the syntheses. All the covalently immobilised Ni(II)-complexes displayed enzyme-like activity. They also were active in the liquid-phase oxidation of cyclohexene, providing the epoxide with high selectivity. [ABSTRACT FROM AUTHOR]

Highlights: [•] Registering the far IR spectra of metal ion-monofunctional ligand complexes. [•] Assigning metal ion–Nimidazole(amino) or metal ion–O(carboxylate) vibrations. [•] Transferring the data to the far IR spectra of grafted Ni(II)–amino acid complexes. [ABSTRACT FROM AUTHOR]