Synthesis and crystal structure of unprecedented oxo/hydroxo-bridged polynuclear gallium(III) aqua complexes

Two new polynuclear oxo/hydroxo-bridged polynuclear gallium(III) aqua complexes are obtained upon treatment of Ga3+(aq) with pyridine: the supramolecular compound of macrocyclic cavitand cucurbit[6]uril with gallium complex containing 32 metal atoms [Ga-32-(mu(4)-O)(12)(mu(3)-O)(8)(mu(2)-O)(7)(mu(2)-OH)(39)(H2O)(20)](PyH subset of C36H36N24O12)(3)(NO3)(6)center dot 53H(2)O (1) and the tridecanuclear complex [Ga-13(mu(3)-OH)(6)(mu 2OH)(18)(H2O)(24)](NO3)(15)center dot 12H(2)O (2). It follows that two modes of nucleation exist when Ga3+(aq) is hydrolyzed: one around the tetrahedral GaO4 units (complex 1) and the other around the octahedral GaO6 units (complex 2). This is the first time that polynuclear oxo/hyd roxo-b ridged aqua complexes of Ga(III) have been isolated without the use of other ligands to control or block olygomerization.