Chen, Ting Huo, Peng Hou, Jin-Le Xu, Jing Zhu, Qin-Yu Dai, Jie Confinement Effects of Metal–Organic Framework on the Formation of Charge-Transfer Tetrathiafulvalene Dimers Three transition metal coordination polymers (CPs) based on the redox-active dimethyl­thio-tetra­thia­fulvalene-bicarbox­ylate (L) and 1,3-bi­(4-pyridyl)­propane (bpp) ligands, formulated as [MnL­(bpp)]<sub><i>n</i></sub> (<b>1</b>), [CdL­(bpp)]<sub><i>n</i></sub> (<b>2</b>), and [Cd<sub>2</sub>L­(bpp)<sub>2</sub>­(H<sub>2</sub>O)­(C<sub>2</sub>O<sub>4</sub>)<sub>0.5</sub>]<sub><i>n</i></sub>·<i>n</i>(ClO<sub>4</sub>)·<i>n</i>(H<sub>2</sub>O) (<b>3</b>), are crystallographically characterized. Complexes <b>1</b> and <b>2</b> are isostructural 2-D polymers, and <b>3</b> features an unusual 3-D metal–organic framework (MOF). The 3-D MOF is constructed from tetranuclear cluster nodes built through the μ<sub>2</sub>-O bridge of the TTF ligand, which is first found for TTF coordination polymers. It is found that the channel generated by the 3-D MOF exerts a confinement effect on the formation of TTF dimers. The TTF dimers show strong intradimer interaction with partial electron transfer or charge transfer, and hence, the Cd compound <b>3</b> has relatively good photocurrent response property in comparison with that of 2-D Cd compound <b>2</b>. confinement effect;isostructural 2- D polymers;Complexes 1;Charge-Transfer Tetrathiafulvalene Dimers;O bridge;TTF dimers;Confinement Effects;Cd compound 3;μ 2;electron transfer;3- D MOF;H 2 O;TTF ligand;CP;TTF coordination polymers;tetranuclear cluster nodes;charge transfer;intradimer interaction;transition metal coordination polymers;photocurrent response property;3 features;2- D Cd compound 2;TTF dimers show 2016-12-01