2-Pyridyl aldoxime in cobalt carboxylate chemistry: Synthesis and characterization of trinuclear complexes

摘要

The use of 2-pyridyl aldoxime (pyCHNOH) in cobalt carboxylate chemistry has yielded compounds 2[Co_3~(III)O(O2CPh)3(pyCHNO)3][Co_3~(II)(O2CPh)8] · 7.67MeCN (1 · 7.67MeCN) and [Co_3~(II)O(O2CPh)3(pyCHNO)3] (PhCO2) ·0.5PhCO2H · 2MeCN (2 · 0.5PhCO2H · 2MeCN) in mixture, as well as compounds 2[Co_3~(III)O (O2CPh)3(pyCHNO)3](PhCO2)(NO3) · (PhCO2H) · H2O (3 · PhCO2H · H2O) and [Co_2~(III)Co~(II)(OH)Cl3(pyCHNO)4]· 0 · 5MeCN · 0.5H2O (4 · 0.5MeCN · 0.5H2O). Complexes 1-3 have been isolated from the 1:1:2 CoX2(X = Cl~-,NO_3~-)/pyCHNOH/PhCO2Na molar ratio reactions in MeCN, whereas the 1:1:1 CoX2(X = Cl~-)/pyCHNOH/PhCO2Na molar ratio reaction in MeCN afforded complex 4. Compounds 1-3 contain the cation [Co_3~(III)O(O2CPh)3(pyCHNO)3]~+ representing the first triangular oxo-centred Co~(III) cluster with pyCHNO~-, whereas compound 4 displays an unusual structural motif consisting of dinuclear [Co_2~(III)(μ2-OH)(pyCHNO)4]~+ and tetrahedral [Co~(II)Cl3]~- units bridged by an oximato oxygen atom of the ligand.