摘要
Diruthenium ethynyl complexes 1--3 （1： 1,5-dithia-s-indacene-4,8-dione; 2： 4,8-diethoxybenzo[1,2-b：4,5- b＇]dithiophene; 3： 4,8-didodecyloxybenzo[1,2-b：4,5-b＇]dithiophene） have been synthesized by incorporating the re- spective conjugated heterocyclic spacer and characterized by NMR and elemental analysis. The effects of bridge ligands＇ properties on electronic coupling between redox-active ruthenium terminal groups were investigated by electrochemistry, UV/vis/near-IR and IR spectroelectrochemistry combined with density functional theory （DFT） and time-dependent DFT calculations. Electrochemistry results indicated that complexes 1--3 exhibit two fully re- versible oxidation waves, and complexes 2 and 3 with electron-rich and π-conjuagted bridge ligands are character- ized by excellent electrochemical properties. Furthermore, the larger v（C≡C） separation from the IR spectroelec- trochemical results of 2 and 3 and the intense NIR absorption features of singly oxidized species 2＋ and 3＋ re- vealed that their molecular skeletons have superior abilities to delocalize the positive charge. The spin density dis- tribution from DFT calculations proved the conclusions of this study.
Diruthenium ethynyl complexes 1--3 （1： 1,5-dithia-s-indacene-4,8-dione; 2： 4,8-diethoxybenzo[1,2-b：4,5- b＇]dithiophene; 3： 4,8-didodecyloxybenzo[1,2-b：4,5-b＇]dithiophene） have been synthesized by incorporating the re- spective conjugated heterocyclic spacer and characterized by NMR and elemental analysis. The effects of bridge ligands＇ properties on electronic coupling between redox-active ruthenium terminal groups were investigated by electrochemistry, UV/vis/near-IR and IR spectroelectrochemistry combined with density functional theory （DFT） and time-dependent DFT calculations. Electrochemistry results indicated that complexes 1--3 exhibit two fully re- versible oxidation waves, and complexes 2 and 3 with electron-rich and π-conjuagted bridge ligands are character- ized by excellent electrochemical properties. Furthermore, the larger v（C≡C） separation from the IR spectroelec- trochemical results of 2 and 3 and the intense NIR absorption features of singly oxidized species 2＋ and 3＋ re- vealed that their molecular skeletons have superior abilities to delocalize the positive charge. The spin density dis- tribution from DFT calculations proved the conclusions of this study.
基金
The authors acknowledge financial support from Na- tional Natural Science Foundation of China （No. 21602049） and the Natural Science Foundation of Hu- nan Province, China （No. 2017JJ3004）.
