TY - JOUR

T1 - Guests Like Gear Levers

T2 - Donor Binding to Coordinatively Unsaturated Metal Sites in MIL-101 Controls the Linker′s Rotation

AU - Khudozhitkov, Alexander E.

AU - Arzumanov, Sergey S.

AU - Kolokolov, Daniil I.

AU - Kholdeeva, Oxana A.

AU - Freude, Dieter

AU - Stepanov, Alexander G.

N1 - © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

PY - 2019/4/5

Y1 - 2019/4/5

N2 - We present investigation of the effect of electron-donor guests on framework mobility in the metal–organic framework (MOF) MIL-101(Cr) monitored by solid state 2 H NMR spectroscopy. In a guest-free material, the mobile phenylene fragments of the terephthalate (TP) linkers populate two fractions with notably different kinetic parameters for torsional motion. Two fractions of rotational motion are indicative of non-equivalence of TP linker binding to the Cr 3 O trimer, the primary building unit of the MIL-101 framework. It is established that the interaction of the guest molecules with coordinatively unsaturated metal sites (CUS) of the MOF dramatically decreases torsional barriers for the linker motions, enhancing the rotation rate. This result is opposite to a more conventional slowing down effect on the linker rotation of the guests not selectively interacting with the adsorption sites inside the framework of the MOFs. The effect of coordination on both the torsional barrier and the rotation rate depends notably on the particular guest interacting with the CUS. The found effects of the guest on the rotational motion represent a basis for developing the strategy for ruling and controlling the linker rotation in MOFs with CUS. It is shown that if water occupies CUS, another guest (tert-butanol, cyclohexanone) fails to competitively coordinate to the site.

AB - We present investigation of the effect of electron-donor guests on framework mobility in the metal–organic framework (MOF) MIL-101(Cr) monitored by solid state 2 H NMR spectroscopy. In a guest-free material, the mobile phenylene fragments of the terephthalate (TP) linkers populate two fractions with notably different kinetic parameters for torsional motion. Two fractions of rotational motion are indicative of non-equivalence of TP linker binding to the Cr 3 O trimer, the primary building unit of the MIL-101 framework. It is established that the interaction of the guest molecules with coordinatively unsaturated metal sites (CUS) of the MOF dramatically decreases torsional barriers for the linker motions, enhancing the rotation rate. This result is opposite to a more conventional slowing down effect on the linker rotation of the guests not selectively interacting with the adsorption sites inside the framework of the MOFs. The effect of coordination on both the torsional barrier and the rotation rate depends notably on the particular guest interacting with the CUS. The found effects of the guest on the rotational motion represent a basis for developing the strategy for ruling and controlling the linker rotation in MOFs with CUS. It is shown that if water occupies CUS, another guest (tert-butanol, cyclohexanone) fails to competitively coordinate to the site.

KW - materials science

KW - metal–organic frameworks

KW - rotation control

KW - solid state NMR spectroscopy

KW - structural mobility

KW - SELECTIVE OXIDATION

KW - MOLECULAR ROTORS

KW - CO2

KW - DYNAMICS

KW - ORGANIC FRAMEWORKS

KW - metal-organic frameworks

KW - FAMILY

UR - http://www.scopus.com/inward/record.url?scp=85063268286&partnerID=8YFLogxK

U2 - 10.1002/chem.201900585

DO - 10.1002/chem.201900585

M3 - Article

C2 - 30811710

AN - SCOPUS:85063268286

VL - 25

SP - 5163

EP - 5168

JO - Chemistry - A European Journal

JF - Chemistry - A European Journal

SN - 0947-6539

IS - 20

ER -