Reactivity in polynuclear transition metal chemistry as a means to obtain high-spin molecules: substitution of µ4-OH– by η1,µ4-N3– increases nine times the ground-state S value of a nonanuclear nickel(ii) cage

The reaction of di-2-pyridyl ketone, (2-py)2CO, with Ni(O2CMe)(2).4H2O yields the cage [Ni9(OH)2(O2CMe)8((2-py)2CO2)4], which reacts further with N3- ions to give the structurally similar cluster [Ni9(N3)2(O2CMe)8((2-py)2CO2)4] containing extremely rare eta 1,mu 4-N3- groups; magnetic studies reveal that the spin ground state of the latter is nine times the ground state of the former.