3D Coordination Framework with Uncommon Two-Fold Interpenetrated {33⋅59⋅63}-lcy Net and Coordinated Anion Exchange



Unusual {33⋅59⋅63}-lcy topology has been found in an uncommon 3D six-connected, two-fold interpenetrated {335963}-lcy net (illustrated). The coordinated SO42− 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.

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Reaction of tetrazole-1-acetic acid with CuSO45H2O produces two novel 3D coordination frameworks: ([Cu33-OH)(η1113-SO4)(tza)3]3 CH3OHH2O}n (1; Htza=tetrazole-1-acetic acid) and {[Cu42-OH)(η224-SO4)(tta)5]3 H2O}n (2; Htta=tetrazole). Framework 1 is constructed from a trinuclear copper cluster [Cu33-OH)(η1113-SO4)] and displays a six-connected framework with uncommon {335963}-lcy topology. Framework 2 presents a complicated five-nodal (3,4,6)-connected net with (426)(342527)(43628)(32485362)(4686103) topology. The η224-SO4 bridging mode in 2 has not been found in the reported coordination polymers. The coordinated SO42− 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.