Alkali Metal/Lanthanoid Heterobimetallic Complexes of 8‐Hydroxyquinolines Accessed by Pseudo‐Solid‐State Reactions

Abstract

Abstract The heterobimetallic 1D‐polymeric alkali metal/lanthanoid [AMLn(Q) 4 ] n [Q = OQ (8‐quinolinolate): AM = Li, Ln = Tb, Ho, Er; AM = K, Ln = Er; Q = MQ (2‐methyl‐8‐quinolinolate): AM = Rb; Ln = Tb, Er] complexes were obtained after rearrangement reactions between AM(Q) and Ln(Q) 3 in a 1,2,4,5‐tetramethylbenzene flux at elevated temperatures. In these compounds, the eight‐coordinate lanthanoid ion is surrounded by four (O, N) chelating Q ligands, which bridge to the adjacent alkali metal through their oxygen atoms to form the linear polymers. Dimeric [Cs 2 (MQ) 2 (HMQ) 2 ] was obtained from an attempt to prepare [CsEr(MQ) 4 ] n , and the caesium atoms are each ligated by one terminal HMQ and one chelating‐bridging MQ ligand. In addition, the chelating‐bridging ligands in [Cs 2 (MQ) 2 (HMQ) 2 ] and in the rubidium derivatives [RbLn(MQ) 4 ] n (Ln = Tb, Er) exhibit bonding of the π‐electron system to coordination saturate the large ionic alkali metal ion. The reaction of Yb(MQ) 3 in the presence of K 2 C 2 O 4 · H 2 O afforded the monomeric heterobimetallic [KYb 2 (MQ) 7 ] complex in which the three metal atoms are arranged in a triangular fashion. They are surrounded by seven MQ ligands, which display the previously encountered chelating (O, N) and the chelating‐bridging μ‐κ 2 (N,O):κ 1 (O) and μ 3 ‐κ 2 (N,O):κ 1 (O):κ 1 (O) ligation modes. Heating K(OQ) in 1,2,3,4‐tetrachlorobenzene gave crystals of 8‐hydroxyquinolinium chloride. The structure of [Na 4 (OQ) 4 (H 2 O) 8 ] n , obtained by neutralisation, has sodium ions coordinated by one chelating OQ and four aqua ligands, the latter bridge to adjacent sodium ions to give a double stranded 2D‐polymer.