Reversible single crystal to single crystal transformation with anion exchange-induced weak Cu2+⋯I− interactions and modification of the structures and properties of MOFs

{[Cu(6)(TTTMB)(8)(OH)(4)(H(2)O)(6)]·8(NO(3))·34.5H(2)O}(n) can reversibly transform to {[Cu(6)(TTTMB)(8)I(3)]·9I·26H(2)O}(n) upon a single crystal to single crystal process. The transformation is accompanied by the formation of weak Cu(2+)I(-) interactions and changes in the coordination numbers, as well as modulation in their properties.