New heterometallic coordination polymers based on zinc(II) complexes with Schiff-base ligands and dicyanometallates: synthesis, crystal structures, and luminescent properties

Abstract

AbstractFour new d10 heterometallic coordination polymers have been obtained using three Schiff-base ligands, zinc(II) nitrate, and dicyanometallates: 1∞[{Zn3(Salen)2}{μ-Au(CN)2}2] (1); 1∞[Zn(Saldmen){μ-Ag(CN)2}]·2H2O (2); 1∞[Zn(Salampy){μ-Ag(CN)2}] (3); 1∞[Zn(Salampy){μ-Au(CN)2}] (4). The Schiff bases are obtained from condensation of salicylaldehyde with ethylenediamine (H2Salen); N,N-dimethyl-ethylenediamine (HSaldmen) and, respectively, 2-aminomethyl-pyridine (HSalampy). The dicyanometallates are K[Ag(CN)2] and K[Au(CN)2]. The compounds were characterized by X-ray single-crystal diffraction, infrared spectroscopy, UV–vis spectroscopy, and elemental analysis. In compound 1, the homotrimetallic units, {Zn3(salen)2}2+, are connected by two [Au(CN)2]− bridges, forming a 1-D double chain. In compounds 2–4, the crystal structures show polymeric zigzag chains generated by the mononuclear zinc(II) nodes and [M(CN)2]− spacers. The luminescence properties of the new heterometallic polymers have also been investigated.The self-assembly processes between homotrimetallic, {Zn3(salen)2}2+, and mononuclear, {Zn(Saldmen)}+, {Zn(Salampy)}+, units and dicyanometallates, generate new polymeric 1-D chains. In compound 1 the homotrimetallic units, {Zn3(salen)2}2+, are connected by two [Au(CN)2]− bridges, forming 1-D double chain. In compounds 2–4 the crystal structures show polymeric 1-D chains generated by the mononuclear zinc(II) nodes and [M(CN)2]− spacers.Keywords: Zinc–silver heterometallic complexesZinc–gold heterometallic complexesSchiff-base ligandsLuminescence AcknowledgementsFinancial support from the UEFISCDI (Project PN-II-ID-PCCE-2011-2-0050) is gratefully acknowledged. This work was carried out within the research program Coordinative and Supramolecular Chemistry of the ''Ilie Murgulescu'' Institute of Physical Chemistry, Romanian Academy.