Halocadmium Clusters with Different Linkage Modes Templated by Methyl Viologen: Structure, Photoluminescence, and Thermochromism

A new halocadmium/methyl viologen hybrid (MV)4(Cd2I6)(Cd2I7)2 (1) (MV2+ = methyl viologen) has been structurally determined. In 1, two kinds of dimeric halocadmium clusters constructed from edge/vertex-sharing CdI4 tetrahedra respectively, i.e., Cd2I6 2− and Cd2I7 − dimmers were observed, which were templated by methyl viologen cation (MV2+). A highly interesting feature of 1 is the presence of mixed type dimeric halocadmium clusters in one crystal lattice templated by one kind of cation. 1 displays photoluminescences, and its thermochromism behavior is observed, whose mechanism was verified by theoretical calculations.