Cu^II Coordination Polymers Capable of Gelation and Selective SO₄^–2 Separation

A crystal engineering rationale has been exploited to generate a series of CuII coordination polymers namely [{Cu­(μ-L1)­(SO4)­(H2O)3}·H2O]∝ CP1, [{Cu­(μ-L1)2(H2O)2}­F·2H2O]∝ CP2 [{Cu­(μ-L1)2(H2O)2}­Cl·H2O]∝ CP3 and [{Cu­(μ-L1)2(H2O)2}­Br·H2O]∝ CP4 derived from N, Ń-(3-pyridyl) m-phenyleneurea (L1) capable of gelling aqueous solvents (DMF/water); in situ crystallization of CP1 has been exploited to separate SO42‑ anion selectively from a complex mixture of oxo anions (SO42–, NO3–, ClO4–, CF3SO3–). While the gels are characterized by optical-, scanning electron microscopy and rheology, structure–property (gelation, as well as anion separation) correlation has been attempted by using single crystal- and powder-X-ray diffraction data.