Bimetallic Salen-Based Compounds and Their Potential Applications

Abstract

The new bimetallic coordination compounds [LNiAg­(NO3)], [LCuMn­(NO3)2], [LCuCu­(NO3)2], [LCuZn­(NO3)2], and [{LCuBi­(NO3)3}­(ACN)] have been synthesized from a salen-type ligand L containing two distinct coordination sites to accommodate (different) metal ions M1 and M2. In the solid state, the formation of 1:1 compounds (LCu:M2) is always observed, but interactions between the compounds lead to differences in packing. For example, a head-to-tail arrangement along the crystallographic b-axis is observed in the case of the LCuBi compound, and the LNiAg compound is polymeric, while its Cu homologue LCuAg forms a discrete dimer. Given the inherent potential of the preorganizing, two metal ions using L could be used to synthesize nanoscale copper–bismuth and −manganese mixed metal oxides as a function of the temperature. The combination of different bioactive metal ions within one ligand system was furthermore explored for antimicrobial efficiency.

New Antimicrobial Strategies Based on Metal Complexes

“…Another reason could be the strength of the salen ligand, drastically limiting the progressive release of its metal ion, while the second one is less strongly coordinated. This is confirmed by the biological analysis: the antimicrobial activities of the bimetallic compounds are similar to those of the second metal ion, suggesting that the coordination hides the first one to its environment, reducing its biodisponibility [184].…”

Enhancement of Alkali Metal Ion Recognition by Metalation of a Tris(saloph) Cryptand Having Benzene Rings at the Bridgeheads

“…The geometry of the LNi 3 host moiety in the LNi 3 ·Ag complex was quite similar to that of the guest-free LNi 3 (Table ); the pivot–pivot distances of these structures are very similar (LNi 3 , d piv = 5.523 Å; LNi 3 ·Ag, d piv = 5.594 Å). Two oxygen atoms in one of the three [Ni­(saloph)] arms coordinate to the Ag + ion with the distances d GO ≈ 2.43 Å, which are similar to those found in the related dinuclear [Ni­(salen)·Ag] structures . In addition, the distances between the Ag + ion and pivotal benzene rings are found to be d GP = 2.70 and 2.76 Å, which are within the range of the reported Ag−π distances .…”