Isocationic substitution of copper(II) complexes in anisotropic materials based on benzenetricarboxylate

Abstract

A phase transfer isocationic substitution of lattice constituent macrocyclic complexes by copper(II) aqua complexes occurs upon the interaction of crystalline mono-and bis(macrocyclic) copper carboxylate complexes with acetonitrile solutions of copper(II) ammine complex. On the other hand, these materials do not react with cupric bis(ethylenediamine).Interest has recently increased in a new class of crystalline materials, namely, organometallic frameworks (OMF). These materials are coordination compounds, in which metal ions are bound to organic ligands [1]. Crystal hydrates are a particular class of OMF consisting of copper(II) and nickel(II) azamacrocyclic complexes and aromatic carboxylates and form a broad range of lattices with cavities and/or channels or laminar structure [2]. As a consequence of these features, such OMF are capable of adsorbing some organic and inorganic molecules either from the gas phase or liquids [2].Alcohols are the most common adsorbates in these studies [3][4][5][6][7]. This activity may be attributed to the hydrophilic nature of the cavity surfaces in the lattices of these OMF and the possibility of forming hydrogen bonds between the interacting components. The similarity of the volume of OMF cavities and the total volume of the adsorbed alcohol molecules such as methanol and ethanol indicates binding of the guests in the adsorbent channels. On the other hand, in the case of phenol, this parameter is not always related to the cavity volume due to the possibility of intercalation of the adsorbate between the adsorbent layers [3,4]. The structural factor, i.e., agreement of the pore size and geometrical parameters of the adsorbate is not a principal requirement in the adsorption of small monohydric alcohols but becomes predominant in interaction with large molecules. Thus, OMF derived from the macrocyclic nickel complex [Ni(cl)(H 2 O) 2 ] 3 (BTC) 2 ·24H 2 O (cl = 1,4,8,11-tetraazacyclotetradecane, cyclam, BTC 3-is the 1,3,5-benzenetricarboxylate anion) efficiently bind D-glucose but do not interact with maltose (glucose dimer) [8].The interaction of such framework materials with metal complex species has been studied much less extensively although we might expect high selectivity in systems of OMF adsorbents and metal complex adsorbates in light of the fit of the geometrical dimensions of the adsorbate and adsorbent pores and the complementary spatial nature of the reagents from the viewpoint of a chemical reaction between them. Furthermore, since the adsorbed metal complexes are in a molecularly dispersed state within the matrix, their subsequent transformations may lead to the formation of hybrid materials containing new types of nanoparticles or clusters in the OMF cavities.0040-5760/07/4302-0131

Effect of the type of crystal lattice in nickel(II) and copper(II) macrocyclic carboxylates on absorption of copper amine complexes from solutions

“…2, curves 3 and 4). We observed a similar pattern earlier for analogous processes with participation of MOFs based on copper(II) macrocyclic complexes [11]. At the same time, the reaction product of the 1D CP [2ÌCu] mainly retains the original crystal lattice, although changes in the intensity of the signals and broadening of the reflections in the low-angle range may suggest certain changes in its structure (Fig.…”

“…At the same time, the kinetic curves for reactions with participation of the nickel complex 6 and the copper complex 7 suggest slower occurrence of the processes, and they do not saturate even after 21 days. In this case, even in the initial stage we observe that the corresponding macrocyclic components of the MOF go into solution, which may indicate their substitution by adsorbate, as we observed earlier for crystalline sorbents based on copper(II) macrocyclic complexes [11].…”

“…As in cases described earlier [9][10][11], the MOFs studied in this work were crystal hydrates (Table 1). As the solvent, we used anhydrous acetonitrile because the crystal compounds are insoluble in it and hydrolysis of dissolved copper(II) amine complexes is inhibited under such conditions.…”

“…Such an approach made it possible to obtain new composite catalysts containing nanoclusters of metals, dispersed in a sorbent matrix [7]. Several papers have also been published that are devoted to the study of sorption processes in (crystalline sorbent (MOF))/(solution containing nonvolatile metal-containing compounds) systems, where the nonvolatile compounds include in particular HgCl 2 [8] or [Cu(NH 3 ) 4 ](ClO 4 ) 2 [9][10][11]. For the latter adsorbate, it has been shown that reactions with participation of nickel-containing MOFs occur with retention of the crystal lattice of the sorbent [9, 10], while in 58 0040-5760/10/4601-0058…”

“…the case of copper-containing MOFs, in the initial chemisorption step already isocharge substitution of the component MOFs occurs to form copper (aqua)(amino) complexes, with a change in the crystal lattice [11].…”