Two New Methyl Viologen Halocadmium Charge-Transfer Salts with Isostructures: Visible-Light Excited Photoluminescences, Thermochromisms and Theoretical Studies

摘要

Two new methyl viologen halocadmium charge-transfer salts with isostructures, [(MV)(CdI4)](2)center dot 3H(2)O (1) and (MV)(CdI4)center dot H2O (2) (MV = methyl viologen, i.e., 1,1'-dimethyl-4,4'-bipyridinium), have been structurally determined. 1 and 2 consist of CdI4 (2-) clusters, MV2+ dications, lattice waters with isostructures, and C-H center dot center dot center dot I hydrogen bonds are presented in 1 but absent in 2, furthermore, their relative stabilities based on were investigated by DFT calculations. Both compounds display photoluminescences in the visible region under visible-light excitations, and their thermochromism effects are observed. But their photoluminescence and thermochromic behaviors differ greatly with the presence or absence of hydrogen bonds. Moreover, their absorption spectra have also been discussed.