A NOVEL ROUTE FOR THE PREPARATION OF HYDROTALCITE AND SYNTHESIS OF INTERCALATED REVERSIBLE DIOXYGEN-CARRYING COBALT(II) COMPLEXES

Reacting a solid MgCO3 . 3H(2)O or Mg-5(CO3)(4)(OH)(2) . 5H(2)O (nesqu ehonite, hydromagnesite, dypingite) with an aqueous solution of sodium aluminate and sodium hydroxide is a novel procedure to synthesize sol id solutions with desired stoichiometric Mg/Al ratios in the hydrotalc ite series [Mg3-xAl(OH)(8-2x)](2)[(CO3)(H2O)(4-x)] (0 less than or equ al to x less than or equal to 1). By mixing of an intermediate solid s olution of magnesium aluminium oxide obtained by thermal decomposition of hydrotalcite with an aqueous solution of mono- or alpha,omega-dica rboxylates which contain N-donor atom in the presence of ethylene glyc ol as a swelling agent pillared aminocarboxylate derivatives of hydrot alcite are produced. Nitrogen donor atoms of aminocarboxylate pillars may react with cobalt(II) complexes to form coordinatively unsaturated cobalt(II) chelates. The synthesized model Co(salen) and Co(salophen) complexes immobilized in the interlayer region of anionic clays rever sibly bind dioxygen and enjoy high stability in the course of oxygenat ion-deoxygenation cycles.