The remarkable structural diversity of alkali metal pyridine-2-thiolates with mismatched crown ethers

Scott Chadwick, Karin Ruhlandt-Senge

Research output: Contribution to journalArticle

47 Scopus citations

Abstract

The metathesis reaction of butyllithium or sodium or potassium hydride with pyridine-2-thiol is effected in ethereal or hydrocarbon media, where the addition of crown ether (which is essential in the case of sodium hydride) facilitates the metalation step. The reaction is driven forward irreversibly by the evolution of a volatile component (C4H10 or H2). It is shown that the choice of crown ether is of paramount importance in determining the solid-state structural outcome. When the cavity size of the crown ether is matched with the alkali metal ionic radius, simple monomeric formulations are identified in [Li(12C4)(NC5H4S-2)] (1) (12C4=[12]crown-4), [Na(15C5)- (NC5H4S-2)] (2) (15C5=[15]crown-5), and [K(18C6)(NC5H4S-2)] (3) (18C6= [18]crown-6), although the geometrical relationship between cation and anion in this series has proven to be more complex than was anticipated. The complexes resulting from the pairing of crown ethers that are either too small or too large relative to the alkali metal exhibit a rich structural diversity that is a direct function of the macrocyclic donor: dimeric [{Li(NC5H4S-2)}2{18C6}] (4) and monomeric [Na(18C6)(NC5H4S-2)] (5) are formed in the presence of 18C6; the unprecedented metalloanionic [{Na(12C4)2}2{Na(NC5 H4S-2)2(thf)}{Na(NC5H4μ-S-2) (NC5H4S-2)}]2 (6), with two hitherto unknown metallates, is obtained when 12C4 is employed; and the unusual polymeric [{K(μ-NC5H4-μ-S-2)}2{15C5}]∞ (7) results from the templating ability of 15C5. All complexes reported have been identified primarily through single-crystal X-ray structural analysis together with 1H and 13C NMR (solubility permitting), IR spectroscopy, and melting point determination.

Original languageEnglish (US)
Pages (from-to)1768-1780
Number of pages13
JournalChemistry - A European Journal
Volume4
Issue number9
DOIs
StatePublished - Sep 1 1998

Keywords

  • Alkali metals
  • Coordination modes
  • Crown compounds
  • Metallacycles
  • Solid-state structures
  • Thiolates

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry

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