Design of Conducting Metal-Organic Framework: Orbital- Level Matching in MIL-140A Derivatives

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1 Supporting Information Design of Conducting Metal-Organic Framework: Orbital- Level Matching in MIL-140A Derivatives Tokutaro Komatsu,*, Jared M. Taylor,,, and Hiroshi Kitagawa,,,# Division of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto , Japan CREST, Japan Science and Technology Agency (JST), 7 Goban-cho, Chiyoda-ku, Tokyo , Japan Institute for Integrated Cell-Material Sciences (icems), Kyoto University, Yoshida, Sakyo-ku, Kyoto , Japan # INAMORI Frontier Research Center, Kyushu University, Motooka 744, Nishi-ku, Fukuoka , Japan. 1. Calculation Methods Structural optimization based on band calculations were carried out using density functional theory (PBE functional S1 ) implemented in CASTEP S2 in Materials Studio (Accelrys Software Inc.). Plane-wave basis functions were used with ultrasoft pseudopotentials. S3 Cutoff energies of the basis set and the k-mesh sizes are summarized in Table S1. Prior to the optimization, the hydrogen and/or the fluorine atoms were attached to the phenyl rings assuming an sp 2 hybridization. The initial structure of Ni(BHT) (BHT = benzenehexathiol) is deduced from the lattice parameter and the space group given in the reference. S4 The crystal structures for [Cd(3-bpd)(SCN) 2] S5, Mn 2(DSBDC) S6, monoclinic ZrO 2 (baddeleyite) S7 and TiO 2 (rutile) S8 are taken from the papers, and used without optimization. The parameters used for the band dispersions and the partial density of states are summarized in Table S2. Due to a limitation of computational resources, ultrasot pseudopotentials were used for Ni(BHT) and Mn 2(DSBDC). Table S1. Calculation conditions used for the geometry optimization. Compound Cutoff energy (ev) k-mesh MIL-140A x 1 x 2 MIL-140A(Ti) x 2 x 3 MIL-140A(Ti)F x 2 x 3 Ni(BHT) x 1 x 3 Table S2. Calculation conditions used for band-structure calculations Compound Potential Cutoff energy (ev) k-mesh for PDOS calculation U (ev) MIL-140A norm-conserving x 2 x (Zr) MIL-140A(Ti) norm-conserving x 2 x (Ti) MIL-140A(Ti)F4 norm-conserving x 2 x (Ti) Ni(BHT) ultrasoft x 3 x 7 Mn2(DSBDC)* ultrasoft x 3 x (Mn) [Cd(3-bpd)(SCN)2] norm-conserving x 5 x 5 ZrO2 (baddeleyite) norm-conserving x 9 x (Zr) TiO2 (rutile) norm-conserving x 11 x (Ti) *Antiferromagnetic spin configuration was assumed, assigning the neighboring Mn ions, which are crystallographically unique, have opposite spin to each other. 1

2 2. Crystal Orbitals for MIL-140A Figure S1. (a) Next highest-occupied crystal orbital and (b) highest occupied crystal orbital of MIL-140A. The grey, orange, red and light blue nodes represent carbon, hydrogen, oxygen and zirconium atoms, respectively. 2

3 Figure S2. (a) Lowest unoccupied crystal orbital (LUCO), (b) 5 th LUCO, and (c) 9 th LUCO of MIL-140A. The grey, orange, red and light blue nodes represent carbon, hydrogen, oxygen and zirconium atoms, respectively. 3

4 3. Band Structure and PDOS of [Cd(3-bpd)(SCN) 2] Figure S3. Band structure (leftmost) and partial density of states (DOS) of [Cd(3-bpd)(SCN) 2] S5. Fermi level is taken as zero energy. The red lines in the band structure indicate the lowest CB and highest VB. 4

5 4. Band Structure and PDOS of Mn 2(DSBDC) (a) (b) Figure S4. Band structure (leftmost) and partial density of states (DOS) of Mn 2(DSBDC) S6 for (a) - and (b) spins. Fermi level is taken as zero energy. The red lines in the band structure indicate the three lowest CBs and highest VBs. The band width for spin is larger than that for spin. 5

6 5. Band Structure and PDOS of Ni(BHT) Figure S5. Band structure (leftmost) and partial density of states (DOS) of Ni(BHT) S4. Fermi level is taken as zero energy. The red lines in the band structure indicate the bands that intersect the Fermi level. 6

7 6. PDOS of Partially Ti-substituted MIL-140A Figure S6 shows the PDOS of MIL-140A of which 1/4 of Zr is substituted with Ti. The d-orbitals of Ti form localize in-gap states. Therefore, majority of the Zr 4+ must be exchanged with Ti 4+ to achieve a wide-spread conduction band. Figure S6. PDOS of partially Ti-substituted MIL-140A. Fermi level of pure MIL-140A is taken as zero energy. 7. Band Structure and PDOS of ZrO 2 (baddeleyite) and TiO 2 (rutile) Figure S7. Band structure (leftmost) and partial density of states (PDOS) of monoclinic phase of ZrO 2 (baddeleyite) S7. Fermi level is taken as zero energy. The red lines in the band structure indicate the three lowest CBs and highest VBs. 7

8 Figure S8. Band structure (leftmost) and partial density of states (PDOS) of rutile S8. Fermi level is taken as zero energy. The red lines in the band structure indicate the three lowest CBs and highest VBs. 8

9 8. Effect of Fluorine Substitution of Terephthalate on the HOMO Level and Stability The highest VB of MIL-140A(Ti)F4 is formed by an isolated orbital of L[110]. It may seem to be counter-intuitive that the highest VB become shallower (i.e., the HOMO level of the ligand is raised) by the substitution by F, which is highly electronegative. Actually, the increased electronegativity of the benzene ring attracts extra electrons, which induce a quinoid-type deformation. The deformed system reduces the aromaticity, and thus raise the HOMO level of the perfluorinated terephthalate. The narrow HOMO-LUMO gap and high HOMO level correspond to an increased reactivity of the ligand. So this kind of modification may undermine the stability of the framework. Same kind of destabilization effect by halogen substitution has been reported for MIL-125, S9 in which Cl is predicted to act as a weak electron donor. In contrast with our case, the introduction of -CF 3 to the terephthalate in MIL-125 has devastating effect that breaks up the Ti-O bond. S9 9

10 References (S1) Perdew, J.P.; Burke, K.; Ernzerhof, M. Phys. Rev. Lett. 1996, 77, (S2) Clark, S. J.; Segall, M. D.; Pickard, C. J.; Hasnip, P. J.; Probert, M. J.; Refson, K.; Payne, M. C. Zeitschrift fur Kristallographie 2005, 220, (S3) Vanderbilt, D. Phys Rev B 1990, 41, (S4) Kambe, T.; Sakamoto, R.; Hoshiko, K.; Takada, K.; Miyachi, M.; Ryu, J. H.; Sasaki, S.; Kim, J.; Nakazato, K.; Takata, M.; Nishihara, H., J Am Chem Soc 2013, 135, (S5) Halder, S.; Layek, A.; Ghosh, K.; Rizzoli, C.; Ray, P. P.; Roy, P., Dalton Trans 2015, 44, (S6) Sun, L.; Miyakai, T.; Seki, S.; Dincă, M., J Am Chem Soc 2013, 135, (S7) Sabine, T. M.; Howard, C. J., Acta Cryst 1982, B38, (S8) McCullough, J. D.; Trueblood, K. N., Acta Cryst 1959, 12, (S9) Hendon, C. H.; Tiana, D.; Fontecave, M.; Sanchez, C.; D'Arras, L.; Sassoye, C.; Rozes, L.; Mellot-Draznieks, C.; Walsh, A., J Am Chem Soc 2013, 135,