A doughnut-like (Mn(III))12 metallocycle formed by a rigid angular bis-catecholate with a nanometer-sized central hole.
Reaction of the rigid angular ligand tetrahydroxy-9,10-dimethyl-9,10-dihydro-9,10-ethanoanthracene, hereafter LH(4), with Mn(CH(3)CO(2))(2) x 2 H(2)O in a basic aqueous medium, in air, affords a crystalline product of composition Na(12){[Mn(H(2)O)](12)L(12)} x xH(2)O. Single-crystal X-ray diffraction reveals the presence of large [Mn(III)(12)L(12)](12-) metallocycles of roughly hexagonal appearance, somewhat resembling a doughnut in which the central hole (van der Waals surface to surface) is roughly a nanometer across. This is the first example of a metal derivative of the fully deprotonated form, L(4-). Associations with aquated Na(+) counterions lead to a pleasingly symmetrical packing arrangement resembling honeycomb, with the central holes of individual metallocycles lined up one above the other. The ligand L(4-), on account of its rigid angularity and its strong metal binding properties, promises to provide a rich source of unusual metal-containing structures, in particular cages, in future studies.
School of Chemistry, University of Melbourne, Victoria 3010, Australia. bfa@unimelb.edu.au
Brendan F
BF
Abrahams
Nicholas J
NJ
FitzGerald
Richard
R
Robson