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Miranda R.-A.,Rovira i Virgili University | Miranda R.-A.,Emas Research Center En Ingenieria Of Materiales cro Nanosistemas | Llorca J.,Polytechnic University of Catalonia | Medina F.,Rovira i Virgili University | And 5 more authors.
Journal of Catalysis | Year: 2011

Nanohybrid materials based on polyamino acids immobilized onto inorganic materials are of interest for their potential applications in protein engineering, biomedicine and catalysis. We developed an efficient and eco-friendly new protocol for the immobilization of synthesized poly-l-leucine (PLL) onto rehydrated hydrotalcite (HTr). To do this, we synthesized different PLLs containing both C-terminal and N-terminal groups and compared them with a commercial PLLc. These synthetic polypeptides were immobilized onto HTr in water as the liquid medium with less than 30 min of ultrasound treatment. The obtained PLLs/HTr synzyme showed excellent activity and enantioselectivity when used as a catalyst in the asymmetric Juli-Colonna epoxidation reaction of chalcone. Moreover, these nanohybrid materials based on PLLS did not require any pre-activation time, which were easily separated from the reaction media and, unlike the commercial PLLc-supported catalyst, were reusable, exhibiting high stability after five consecutive runs without any apparent deactivation. © 2011 Elsevier Inc. All rights reserved.


Crivoi D.-G.,Rovira i Virgili University | Crivoi D.-G.,Emas Research Center En Ingenieria Of Materiales cro Nanosistemas | Segarra A.M.,Rovira i Virgili University | Segarra A.M.,Emas Research Center En Ingenieria Of Materiales cro Nanosistemas | And 2 more authors.
Journal of Catalysis | Year: 2016

An efficient one-pot heterogeneous process for producing chiral α,β-epoxy-chalcones from the corresponding aldehydes and ketones has been described. The nanohybrid materials based on poly-l-leucine immobilised into rehydrated hydrotalcites did not require any pre-activation and were easily recovered and recycled for four consecutive runs without losing their catalytic efficiency in terms of conversion, total selectivity towards the corresponding epoxy-chalcones and excellent enantioselectivity. © 2015 Elsevier Inc. All rights reserved.


Crivoi D.-G.,Rovira i Virgili University | Crivoi D.-G.,Emas Research Center En Ingenieria Of Materiales cro Nanosistemas | Miranda R.-A.,Rovira i Virgili University | Miranda R.-A.,Emas Research Center En Ingenieria Of Materiales cro Nanosistemas | And 9 more authors.
Applied Catalysis A: General | Year: 2016

Nanohybrid materials based on l-leucine (l-Leu) and hydrotalcites (HT) were prepared by the ion-exchange and reconstruction method, under mild synthesis conditions. The location, amount and the form of the immobilized l-Leu are affected not only by the time of synthesis, but also by temperature and ultrasound treatment. The XRD results demonstrate that the immobilization occurs in either a vertical or oblique orientation with respect to the HT layers. The catalytic activity of these materials was tested in the aldol addition reaction of cyclohexanone with different aromatic aldehydes, affording mainly the syn-diastereomer. Furthermore, the present study demonstrates that both diastereo- and enantioselectivity can be easily modulated by the appropriate combination of nanohybrid catalyst, solvent and reaction time. © 2016 Elsevier B.V. All rights reserved.

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