2018 Fiscal Year Annual Research Report
Development of metallic conduction and molecular insertion in one-dimensional metal complexes
| Project/Area Number |
18J13022
|
|---|
| Research Institution | Tohoku University |
|---|
Principal Investigator |
Mian Mohammad Rasel 東北大学, 材料科学高等研究所, 特別研究員(PD)
|
|---|
| Project Period (FY) |
2018-04-25 – 2020-03-31
|
| Keywords | One-dimension sysmetm / Pd chain / Pt chain / halogen-bridged / conductivity / infinite structure / optical gap / Raman spectrocopy |
|---|
| Outline of Annual Research Achievements |
Halogen-bridged one-dimension metal (Ni, Pd and Pt) complexes have attracted much attention in the field of pure and applied science due to their excellent physical properties. I have worked on preparation of halogen-bridged 1D Pd/Pt chain complexes. Pd and Pt-based MX-chain complexes usually show M(II)/M(IV) mixed-valance (MV) state. Development of the strategy to achieve M(III) AV state in Pd and Pt-based MX-chain complexes has been important challenge because it definitely provides greater or unprecedented physical properties. Recently, I have reported a new strategy to realize uncommon Pd(III) AV state in bromide-bridged Pd chain complex, [Pd(dabdOH)2Br]Br2 (dabdOH =(2S,3S)-2,3-diaminobutane-1,4-diol), so-called multiple-hydogen-bond” approach (M.R. Mian et al.J. Am. Chem. Soc. 2017, 39, 6562). I introduced hydroxy group to the in-plate ligand and create additional hydrogen bond between hydroxy group and counter anion. When Pd was replaced by Pt, electronic state changes from AV to MV state (M.R. Mian et al. Inorg. Chem. 2019, 58, 114). Conductivity decreases 6 order magnitudes (38 S/cm for Pd and 10-5 S/cm for Pt). However, Br bridged Pd and Pt complexes show smallest optical gap (0.45 eV for Pd and 1.20 eV for Pt) with shortest metal-metal distance. When bridging Br was replaced to Cl, Pd chain exit in AV state, on the other hand, Pt chain exit in MV state. And conductivity decreases from 3 S/cm to insulator.
|
| Current Status of Research Progress |
Current Status of Research Progress
1: Research has progressed more than it was originally planned.
Reason
I was able to control the electronic state of one-dimensional halogen-bridged Pt/Pt chain complexes. Shortest band gap were obtained with highest electronic conductivity. For example, bromo-bridged Pd chain complexes show world's highest conductivity (38 S/cm) in the field of halogen-bridged metal complexes. Shorted metal-metal distance were obtained for Pd and Pt chain complexes.
|
| Strategy for Future Research Activity |
The field of electrically conductive 3D metal organic frameworks (MOFs) has seen tremendous growth in the past several years and has yielded a variety of 2D or 3D MOFs with high electrical conductivity. I will prepare conductive MOFs. It has good advantage to use MOFs: 1) guest molecule can inset to tune their conductivities, 2) large surface area good for gas absorption, etc.In order to obtain the accurate conductivity and to clarify the structural change by guest insertion, single-crystalline electrically conductive MOFs have been anticipated. I believe that MX chains are excellent candidate to be used as pillar of the conductive MOFs. Moreover, they are not just conductive moieties but also have variety of electronic states and physical properties. The electronic states of MX chains are sensitive to d(M-X-M), thus the MX-Chain-based MOFs can change the electronic states by the interaction toward the guest molecules. It also means that guest insertion can be used as the new external stimuli to control the electronic states of MX chains. Although light, pressure and temperature have been used as the external stimuli, nobody has incorporated guest molecules in the MX chains for controlling the electronic states and physical properties.
|
Research Products
(4 results)
