Alkali metal complexes of 6‐methyl‐2‐pyridone: simple formulae, but not so simple structures. Issue 6 (31st October 2013)

• Record Type: Journal Article
• Authors: Clegg, William; Tooke, Duncan M.
• Is Part Of: Acta crystallographica. Volume 69:Issue 6(2013:Dec.)
• Page Start: 603
• Page End: 612
• Publication Date: 2013-10-31
• DOI: 10.1107/S2052519213025980
• Languages: English
• ISSNs: 2052-5206

Abstract

<abstract abstract-type="main" xml:lang="en"> <title> <x xml:space="preserve">Abstract</x> </title> <p>Reaction of 6‐methyl‐2‐pyridone (Hmhp) with Na or K metal, or with Rb or Cs 2‐ethylhexoxide, in an appropriate single or mixed solvent, yields a series of solvated polymeric complexes with the empirical formulae <italic>M</italic>(mhp)(H<sub>2</sub>O)<sub>2</sub> [(1), <italic>M</italic> = Na; (2), <italic>M</italic> = K], <italic>M</italic>(mhp)(H<sub>2</sub>O) [(3), <italic>M</italic> = Rb; (4), <italic>M</italic> = Cs] and Cs(mhp)(<italic>R</italic>OH) [(5), <italic>R</italic> = Me; (6), <italic>R</italic> = Et]. All of the products have been crystallographically characterized and show sheet polymeric structures, except for a double‐chain structure for (2). In all of the structures, mhp<sup>−</sup> and solvent molecules function as bridging ligands; two metal ions are bridged (μ<sub>2</sub>) by each solvent molecule in (1), (5) and (6), while (2) contains both μ<sub>2</sub> and μ<sub>3</sub> triple bridges, and (3) and (4) display highly unusual μ<sub>4</sub> quadruple bridging of metal ions by water molecules. The pyridonate O atom bridges two or three metal ions in each case. Nitrogen is also involved in coordination to the heavier metals; it bonds to a single ion in (3) and (4), but has an almost unprecedented bridging role in (5) and (6). As a result of the extensive bridging by ligands, coordination numbers between 6 and 8 are achieved for the metal ions. In each structure, all solvent OH groups form hydrogen bonds to pyridonate O and, in some cases, N atoms. With one exception, these are the first reported pyridonate complexes of the alkali metals Na–Cs that do not also include transition metals.</p> </abstract>