Two primitive metal-organic frameworks (MOFs), NiL1 and NiL2, based on Ni8O6-cluster and ditopic pyrazolate linkers, L1 (with rigid alkyne arms) and L2 (with flexible alkyne chains), were prepared. The proton conductivities of these MOFs in pristine form and imidazole-encapsulated forms, Im@NiL1 and Im@NiL2, were measured and compared. Upon introduction of imidazole molecules, the proton conductivity could be increased by 3 to 5 orders of magnitude and reached as high as 1.72 × 10−2 S/cm (at 98% RH and 80 ℃). Also, whether imidazole molecules were introduced or not, Ni8O6-based MOFs with L2 in general gave better proton conductivity than those with L1 signifying that flexible side arms indeed assist proton conduction probably via establishment of efficient proton-conducting channels along with formation of highly ordered domains of water/imidazole molecules within the network cavities. Beyond the active Ni8O6-cluster, tuning flexibility of linker pendants serves as an alternative approach to regulate/modulate the proton conductivity of MOFs.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |