TY - JOUR

T1 - Diffusion of benzene in the breathing metal-organic framework MIL-53(Cr)

T2 - A joint experimental-computational investigation

AU - Kolokolov, D. I.

AU - Jobic, H.

AU - Rives, S.

AU - Yot, P. G.

AU - Ollivier, J.

AU - Trens, P.

AU - Stepanov, A. G.

AU - Maurin, G.

PY - 2015/4/16

Y1 - 2015/4/16

N2 - A combination of experimental (quasi-elastic neutron scattering and 2H NMR) and computational (molecular dynamics) tools was used to uncover the molecular mobility of benzene trapped inside the flexible channel-type MIL-53 (Cr3+) MOF. This material was shown to undergo a contraction of the structure upon benzene adsorption with the formation of a narrow pore phase with a smaller aperture. This confinement was found to strongly influence the dynamics of the guest: benzene diffuses in a region centered in the middle of the pore by a 1D-jump translational mechanism along the tunnel ruled by the presence of the μ2-OH groups present at the MOF pore wall. This translational diffusion is combined with a fast uniaxial rotational motion around the C6-axis. Any other rotational motion that involves the tumbling of the phenyl rings about the channel axis is much less probable due to a high activation energy barrier (49 kJ mol-1). In this way benzene can be pictured as a rotating disc that diffuses rapidly through the central part of the channel by short jumps between neighboring low energy basins located in the vicinity of the μ2-OH groups of the MIL-53 channels.

AB - A combination of experimental (quasi-elastic neutron scattering and 2H NMR) and computational (molecular dynamics) tools was used to uncover the molecular mobility of benzene trapped inside the flexible channel-type MIL-53 (Cr3+) MOF. This material was shown to undergo a contraction of the structure upon benzene adsorption with the formation of a narrow pore phase with a smaller aperture. This confinement was found to strongly influence the dynamics of the guest: benzene diffuses in a region centered in the middle of the pore by a 1D-jump translational mechanism along the tunnel ruled by the presence of the μ2-OH groups present at the MOF pore wall. This translational diffusion is combined with a fast uniaxial rotational motion around the C6-axis. Any other rotational motion that involves the tumbling of the phenyl rings about the channel axis is much less probable due to a high activation energy barrier (49 kJ mol-1). In this way benzene can be pictured as a rotating disc that diffuses rapidly through the central part of the channel by short jumps between neighboring low energy basins located in the vicinity of the μ2-OH groups of the MIL-53 channels.

UR - http://www.scopus.com/inward/record.url?scp=84928041179&partnerID=8YFLogxK

U2 - 10.1021/acs.jpcc.5b01465

DO - 10.1021/acs.jpcc.5b01465

M3 - Article

AN - SCOPUS:84928041179

VL - 119

SP - 8217

EP - 8225

JO - Journal of Physical Chemistry C

JF - Journal of Physical Chemistry C

SN - 1932-7447

IS - 15

ER -