Synthesis, Characterization, and DFT Investigation of a Zinc(II)–Silver(I) Bimetallic Complex, [Zn(Dmen)2{Ag(CN)2}2][Zn(Dmen)2(H2O)2]{Ag(CN)2}2 (Dmen = N,N′-Dimethylethylenediamine)

Abstract

A cyanido bridged Zn(II)-Ag(I) bimetallic complex (I) has been prepared and characterized by IR spectroscopy, thermal analysis, X-ray crystallography (CIF file CCDC no. 884016) and DFT calculations. Thermal analysis shows that the composition of the compound is consistent with the proposed stoichiometry, i.e., [Zn(diamine)₂{Ag(CN)₂}₂] · H₂O. The crystal structure of complex I consists of two independent molecules; a trinuclear molecule, [Zn(Dmen)₂{Ag(CN)₂}₂] and an ionic species, [Zn(Dmen)₂-(H₂O)₂]{Ag(CN)₂}₂; the overall formula being [Zn(Dmen)₂{Ag(CN)₂}₂][Zn(Dmen)₂(H₂O)₂]{Ag(CN)₂}₂ (I) (Dmen = N,N′-dimethylethylenediamine). The structures of I and two of its analogues, [Zn(Dmen)₂{Ag(CN)₂}₂]₂ · 2H₂O (II) and {[Zn(Dmen)₂{Ag(CN)₂}][Ag(CN)₂]}₂ · 2H₂O (III) were predicted by DFT calculations. The DFT results reveal that the structure I is more stable in comparison to the calculated structures, II and III. The X-ray structure of I shows that the complex is also stabilized by the argentophilic interactions. The Ag···Ag interaction energy calculated at the MP2 level of theory is –4.02 kcal mol^–1.