3D coordination framework with uncommon two-fold interpenetrated {3(3)5(9)6(3)}-lcy net and coordinated anion exchange.

Unusual {3(3)5(9)6(3)}-lcy topology has been found in an uncommon 3D six-connected, two-fold interpenetrated {3(3)5(9)6(3)}-lcy net (illustrated). The coordinated SO(4) (2-) anions in this framework can undergo a full exchange with Cl(-) anions, in the course of which the crystals change color as shown. The process has a solvent-mediated rather than a solid-state mechanism.Reaction of tetrazole-1-acetic acid with CuSO(4)5H(2)O produces two novel 3D coordination frameworks: ([Cu(3)(mu(3)-OH)(eta(1):eta(1):eta(1):mu(3)-SO(4))(tza)(3)]3 CH(3)OHH(2)O}(n) (1; Htza=tetrazole-1-acetic acid) and {[Cu(4)(mu(2)-OH)(eta(2):eta(2):mu(4)-SO(4))(tta)(5)]3 H(2)O}(n) (2; Htta=tetrazole). Framework 1 is constructed from a trinuclear copper cluster [Cu(3)(mu(3)-OH)(eta(1):eta(1):eta(1):mu(3)-SO(4))] and displays a six-connected framework with uncommon {3(3)5(9)6(3)}-lcy topology. Framework 2 presents a complicated five-nodal (3,4,6)-connected net with (4(2)6)(34(2)5(2)7)(4(3)6(2)8)(3(2)4(8)5(3)6(2))(4(6)8(6)10(3)) topology. The eta(2):eta(2):mu(4)-SO(4) bridging mode in 2 has not been found in the reported coordination polymers. The coordinated SO(4) (2-) anions in 1 can be replaced completely when the solid polymer is treated with an aqueous methanolic solution containing Cl(-) anions. Detailed atomic force microscopy studies indicate a solvent-mediated rather than a solid-state mechanism for the exchange process.