Isopolyoxometalates Derived From Arylstibonic Acids With "Reverse-Keggin Ion" Structures Based On [M(Rsb)(12)O-28] Cores, M = Co(Ii) Or Zn(Ii)

The preparations and structures are described of four new polyoxostibonates, [Co(p-MeC6H4Sb)(12)O-28-{Co(H2O)(3)}(4)]Cl-2 center dot 6H(2)O, [Co(p-ClC6H4Sb)(12)O-28{Co(H2O)(3)}(4)]Cl-2 center dot 22H(2)O, (PhCH2NMe3)(2)-[Zn(p-ClC6H4Sb)(12)O28Zn4Cl2.54Br1.46]center dot 8MeCN.H2O and [BaCoH4(p-MeC6H4Sb)O-28]center dot 5H(2)O. Each of these has a framework of 12 (RSb) groups linked by 28 O atoms, with one transition metal ion in a tetrahedral site in the centre. Other metal ions are coordinated to the polyhedral faces. Three of the complexes have the e Keggin ion geometry, while the fourth is a delta isomer.