Encapsulation of Copper(II) Complexes with Pentadentate N3O2 Schiff Base Ligands in a Pillared Layered Clay

Abstract

Two copper(II) complexes with five-coordinate Schiff-base ligands derived from acetylacetone and with a N 3 O 2 coordination sphere, namely bis(acetylacetonate)-3-amino-bis(propyldiimine) and bis(acetylacetonate)-3-methylamino-bis(propyldiimine), were entrapped in the interlayers of a pillared layered clay (PILC). A two-step process in the liquid phase was used: (i) adsorption of copper(II) acetylacetonate in the porous structure of the PILC, and (ii) in situ Schiff condensation of the copper(II) precursor complex with the corresponding triamine. The new materials were characterised by

Simultaneous aluminium oxide pillaring and copper(ii) Schiff base complexes encapsulation in a montmorillonite

“…As a consequence, in this region there is a significant PILC background absorption that hinders the observation of well-defined metal complex absorptions, as can be inferred by comparing these spectra with those of the materials prepared by in-situ synthesis of the complexes into pre-formed Al-BEN (calcined at 350 uC). 5 Nevertheless, in the spectra of [Cu(acac) 2 trien]@Al-BEN and [Cu(acac) 2 Metrien]@Al-BEN it is possible to observe bands due to the complexes at 1540, 1475, 1438 and 1400 cm 21 . All bands are slightly shifted relative to those of the free complexes, as found in our previous work on encapsulation of the same complexes in Al-BEN by the method of in-situ complex synthesis, 5 and suggests that copper(II) complexes are distorted as a consequence of physical constraints imposed by the matrix.…”

“…5 Nevertheless, in the spectra of [Cu(acac) 2 trien]@Al-BEN and [Cu(acac) 2 Metrien]@Al-BEN it is possible to observe bands due to the complexes at 1540, 1475, 1438 and 1400 cm 21 . All bands are slightly shifted relative to those of the free complexes, as found in our previous work on encapsulation of the same complexes in Al-BEN by the method of in-situ complex synthesis, 5 and suggests that copper(II) complexes are distorted as a consequence of physical constraints imposed by the matrix. The IR spectrum of [Cu(acac) 2 ]@Al-BEN_b is much less informative than those previously discussed, as only a very broad band centred at 1450 cm 21 was observed, which can be assigned to the bending of methyl groups of the complex.…”

“…5 In this work we report the preparation of novel pillared clays based on the same original clay, Benavila (BEN), and into which the same three complexes (Scheme 1) have been incorporated using the simultaneous oligomer pillaring/ complex encapsulation method; the pillaring oligomer was [Al 13 O 4 (OH) 241x (H 2 O) 122x ] (72x)1 , usually denoted as Al 13 71 . All the materials were characterised by X-ray photoelectron spectroscopy, powder X-ray diffraction, low temperature nitrogen adsorption, and infrared spectroscopy and, for copper-based materials, the copper content was determined.…”

CoFe2O4@SiO2@Co(III) Salen Complex: A Magnetically Recyclable Heterogeneous Catalyst for the Synthesis of Quinoline Derivatives in Water

“…Because of the intrinsic advantages of heterogeneous systems including easy catalyst separation/recycling and products separation, an important challenge in catalysis is to transform a successful homogeneous catalyst into a heterogeneous one ,. Supports including zeolite, clays, siliceous materials, and activated carbon has been used for heterogenization of metal complexes . Nanoscience is increasingly advancing.…”

Synthesis and characterization of Co (III) salen complex immobilized on cobalt ferrite‐silica nanoparticle and their application in the synthesis of spirooxindoles

“…One of the most important challenges in catalysis is to transform a successful homogeneous catalyst into a heterogeneous one, due to the intrinsic advantages of heterogeneous systems, namely easy catalyst separation/recycling and products separation . Heterogenization of metal complexes has been carried out using supports, such as zeolite, clays, silicious materials and activated carbon . With the advancement of nanoscience, magnetic nano‐sized particles are becoming increasingly interesting due to their unique applications, such as their uses for cell separation, magnetic resonance imaging, drug delivery systems, protein separation and cancer treatments through hyperthermia .…”