CuI/CuII Complexes with Dipicolinoylbis(N,N‐diethylthiourea): Structures, Magnetism, and Guest Ion Exchange

Abstract

Potassium cations play a vital role in directing reactions of 2,6‐dipicolinoylbis(N,N‐diethylthiourea) (H2L) with Cu(OAc)2. In the absence of K+, a redox reaction occurred, leading to the formation of a polymeric complex [CuIICuI2(L)2]∞ (1). On the other hand, adding a K+ source (i.e KPF6) directs the reaction to a self‐assembly process, forming the {2}‐metallacoronate [CuII2K(L)2](PF6) (2) complexes. The polymeric structure of 1 is built by bridging neighboring [CuIICuI2(L)2] units via Cu2S2 linkages. The supramolecular structure of 2 is constructed by weak interactions between planar [CuII2K(L)2]+ substructures. Cryomagnetic measurements reveal antiferromagnetic interactions between two CuII centers in the same sub‐unit and ferromagnetic interactions between CuII centers of the neighboring sub‐units. The guest K+ cation exchange study for 2 suggests the formation of the [CuII2M(L)2](PF6) series in CH2Cl2 (M = Li, Na, K, Rb and Cs). The stability of the complexes decreases in the order [CuII2K(L)2]+ > [CuII2Na(L)2]+ > [CuII2Rb(L)2]+ > [CuII2Cs(L)2]+ > [CuII2Li(L)2]+.