Structural re-arrangement in two hexanuclear CuII complexes: from a spin frustrated trigonal prism to a strongly coupled antiferromagnetic soluble ring complex with a porous tubular structure

The addition of water to a chloroform solution of the Cu-6 trigonal prism complex [Cu-6(mu F-6)(mu 2OH)(mu 3OCH3)(2)(mu 2OCH3)(2)(3,5-Me(2)pz)(6)] (1) (3,5-Me(2)pz(-) = 3,5-dimethylpyrazolate) results in the formation of the Cu6 planar hexagonal ring complex [Cu-6(mu 2OH)(6)(3,5-Me(2)pz)(6)]center dot CH3CN center dot CHCl3 (2). A simple mechanism for this structural re-arrangement is proposed, in which 2 can be viewed as a hydrolysis product of 1. This process is clearly noticeable in the magnetic properties, which change from spin frustrated with a weak antiferromagnetic coupling in 1, to strongly antiferromagnetic in 2. Interestingly, the hexagonal ring complex 2 self-assembles in the solid state to form a porous hexagonal tubular structure containing guest solvent molecules that can be removed and CO2-exchanged without loss of crystallinity.