Diiron(III) and polymeric iron(III)-sodium complexes with bridging and terminal pyridonate ligands: Structures and magnetic properties

The reaction of anhydrous iron(III) chloride or [NEt(4)](2)[Fe2Cl6O] with equimolar quantities of 6-chloro-2-pyridone (Hchp) and NaOMe in MeOH afforded, after recrystallisation from tetrahydrofuran (thf), the one-dimensional polymer [{Fe(mu-chp)(6)Na-3(mu-MeOH)(6) . 2thf}(n)]1. When the reaction of FeCl3 with NaOMe and Hchp was performed in the presence of 4,4'-dimethyl-2,2'-bipyridine (dmbipy) or 1,10-phenanthroline (phen) the dinuclear complexes [Fe-2(mu-OMe)(2)(chp)(4)(dmbipy)(2)]. 2MeOH 2 or [Fe-2(mu-OMe)(2)(chp)(4)(phen)(2)]. 2MeOH3 resulted. The molecular structures at 150 K and magnetic properties between 1.8 and 280 K of 1-3 have been investigated. Complex 1 displays magnetic behaviour consistent with a paramagnet while 2 and 3 exhibit antiferromagnetic exchange interactions between the spins of the iron(III) ions through OMe bridges (J = -26.8 to -28.6 cm(-1)).