New type of 1D coordination polymeric anions [(MCl3M1Cl3)2−]n (M = Rh, Ru; M1 = Na, K). Crystal structure and IR characterization of Rh(III) and Ru(III) hexachlorometallates with 2-amino-6-methylpyridinium cations

Crystals of sodium bis(2-amino-6-methyl-pyridinium) hexachlororhodium(III) (1) and potassium bis(2-amino-6-methyl-pyridinium) hexachlororuthenium(III) (2) have been prepared in the reaction of MCl3 · xH2O (M = Rh, Ru) with 2-amino-6-methyl pyridine in the presence of M1Cl (M1 = Na or K) in the water solution of HCl. They crystallize in the triclinic space group P1¯, and are isostructural. The cations of metals form infinite chains of [MCl6]–[M1Cl6] octahedra which are achieved by means of six bridging chloride atoms. The chains are interconnected through bifurcated hydrogen bonds established between the NH+ and NH2 groups of the 2-amino-6-methyl-pyridinium cations as well as via C–H⋯Cl type contacts. The aromatic rings of the organic cations form stacks involving π–π interactions, parallel to the infinite [(MCl3M1Cl3)2−]n chains.

Graphical abstractNew type of 1D coordination polymeric anions [(MCl3M1Cl3)2−]n (M = Rh, Ru and M1 = Na, K) has been obtained in the reaction of MCl3 · xH2O and M1Cl with 2-amino-6-methyl-pyridine in hydrochloric acid solution. Their X-ray structures and IR spectra are presented and discussed. Weak hydrogen bonds occur between the organic cations and inorganic polymeric anions to form layers. Organic anions form stacks because of weak π–π interactions between aromatic rings. All metals in 1D coordination polymeric anions are linked together by bridging chloride anions.Figure optionsDownload full-size imageDownload as PowerPoint slide