Synthesis and characterisation of cobalt(ii) phosphonate cage complexes utilizing carboxylates and pyridonates as co-ligands

The synthesis and structures of fifteen new cobalt complexes containing phosphonate ligands are reported. The compounds also utilize carboxylates and 6-chloro-2-pyridonate (chp) as co-ligands. The majority of the compounds are decametallic: [Co 10(chp) 12(O 3PPh) 2(O 2CPh) 4(H 2O) 4], [Co 10(chp) 12(O 3PPh) 2(O 2C tBu) 4(H 2O) 4], [Co 10(chp) 12(O 3PPh) 2(O 2CPh tBu) 4(H 2O) 4], [Co 10(chp) 6(O 3PCH 2Ph) 2(O 2CPh) 8(F) 2 (H 2O) 2(EtOAc) 2], [Co 10(chp) 8(O 3PCH 2Ph) 2(O 2CPh) 8(F) 2(MeCN) 2](HNEt 3) 2, [Co 10(chp) 6(O 3PCH 2Ph) 2(O 2C tBu) 8(F) 2(H 2O) 2(MeCOMe) 2], [Co 10(chp) 6(O 3PMe) 2 (O 2C tBu) 8(F) 2(MeCN) 4], [Co 10(chp) 6(O 3PEt) 2(O 2CPh) 8(F) 2(MeCN) 4], [Co 10(chp) 6(O 3POct) 2(O 2CPh) 8(F) 2(MeCN) 4], [Co 10(chp) 8(Hchp) 2(O 3PCH 2Nap) (O 2CPh) 7(OH) 3(H 2O)], [Co 10(chp) 12(O 3PPh) 2(O 2CPh-2-Ph) 4(H 2O) 4] and [Co 10(chp) 12(O 3PMe) 2(O 2CPh-2-Ph) 4(H 2O) 4]. Two nine-metal cages and one hexametallic cage are also reported: [Co 9(chp) 9(O 3P tBu)(O 2C tBu) 6(OH)], [Co 9(chp) 7(O 3PCH 2Ph) 2(O 3PCH 2Ph)(O 2CCPh 3) 5(OH)(H 2O) 2(MeCN)] and [Co 6(chp) 6(Hchp) 2(O 3P tBu)(O 2CPh-2-Ph) 3(F)(H 2O)](HNEt 3)(Cl). Magnetic studies show predominantly anti-ferromagnetic exchange interactions between the cobalt(ii) sites, with diamagnetic ground states for most of the compounds studied. © 2012 The Royal Society of Chemistry.