scholarly journals Geometric switching of linear to area negative thermal expansion in uniaxial metal–organic frameworks

CrystEngComm ◽  
2014 ◽  
Vol 16 (17) ◽  
pp. 3498-3506 ◽  
Author(s):  
Ines E. Collings ◽  
Matthew G. Tucker ◽  
David A. Keen ◽  
Andrew L. Goodwin

The direction of anisotropic negative thermal expansion switches for the two quartzlike metal–organic frameworks deuterium indium terephthalate and zinc isonicotinate; we show this inversion to be geometric, rather than chemical, in origin.

2019 ◽  
Author(s):  
Jack D. Evans ◽  
Johannes P. Dürholt ◽  
Stefan Kaskel ◽  
Rochus Schmid

Most conventional materials display expansion upon heating, so there is considerable interest in identifying materials that display the opposite behavior, negative thermal expansion (NTE). In the current study, seven mesoporous metal-organic frameworks (MOFs) of varying topology and composition, which exhibit outstanding porosity, were investigated using molecular simulation for temperature-induced contraction. We find exceptional NTE for the most porous MOFs and a correlation between the coefficient of NTE and porosity. The large molecular subunits of the MOFs were further studied to find they intrinsically display NTE, corresponding to terahertz vibrational modes. As a result, NTE has a considerable effect on the mechanical properties of these MOFs and is an important consideration for understanding the mechanical stability of new extremely porous materials.


2007 ◽  
Vol 119 (24) ◽  
pp. 4580-4583 ◽  
Author(s):  
David Dubbeldam ◽  
Krista S. Walton ◽  
Donald E. Ellis ◽  
Randall Q. Snurr

2019 ◽  
Vol 29 (48) ◽  
pp. 1904669 ◽  
Author(s):  
Nicholas C. Burtch ◽  
Samuel J. Baxter ◽  
Jurn Heinen ◽  
Ashley Bird ◽  
Andreas Schneemann ◽  
...  

2018 ◽  
Author(s):  
Adam Sapnik ◽  
Harry Geddes ◽  
Emily Reynolds ◽  
Hamish Yeung ◽  
Andrew Goodwin

<div>We study the structural and thermomechanical effects</div><div>of cation substitution in the compositional family of</div><div>metal–organic frameworks Zn1􀀀xCdx(mIm)2 (HmIm = 2-</div><div>methylimidazole). We find complete miscibility for all</div><div>compositions x, with evidence of inhomogeneous distributions of Cd and Zn that in turn affect framework aperture characteristics. Using variable-temperature X-ray powder diffraction measurements, we show that Cd substitution drives a threefold reduction in the magnitude of thermal expansion behaviour. We interpret this effect in terms of an increased density of negative thermal expansion modes in the more flexible Cd-rich frameworks.</div>


2019 ◽  
Author(s):  
Jack D. Evans ◽  
Johannes P. Dürholt ◽  
Stefan Kaskel ◽  
Rochus Schmid

Most conventional materials display expansion upon heating, so there is considerable interest in identifying materials that display the opposite behavior, negative thermal expansion (NTE). In the current study, seven mesoporous metal-organic frameworks (MOFs) of varying topology and composition, which exhibit outstanding porosity, were investigated using molecular simulation for temperature-induced contraction. We find exceptional NTE for the most porous MOFs and a correlation between the coefficient of NTE and porosity. The large molecular subunits of the MOFs were further studied to find they intrinsically display NTE, corresponding to terahertz vibrational modes. As a result, NTE has a considerable effect on the mechanical properties of these MOFs and is an important consideration for understanding the mechanical stability of new extremely porous materials.


2018 ◽  
Author(s):  
Adam Sapnik ◽  
Harry Geddes ◽  
Emily Reynolds ◽  
Hamish Yeung ◽  
Andrew Goodwin

<div>We study the structural and thermomechanical effects</div><div>of cation substitution in the compositional family of</div><div>metal–organic frameworks Zn1􀀀xCdx(mIm)2 (HmIm = 2-</div><div>methylimidazole). We find complete miscibility for all</div><div>compositions x, with evidence of inhomogeneous distributions of Cd and Zn that in turn affect framework aperture characteristics. Using variable-temperature X-ray powder diffraction measurements, we show that Cd substitution drives a threefold reduction in the magnitude of thermal expansion behaviour. We interpret this effect in terms of an increased density of negative thermal expansion modes in the more flexible Cd-rich frameworks.</div>


2007 ◽  
Vol 46 (24) ◽  
pp. 4496-4499 ◽  
Author(s):  
David Dubbeldam ◽  
Krista S. Walton ◽  
Donald E. Ellis ◽  
Randall Q. Snurr

2008 ◽  
Vol 64 (a1) ◽  
pp. C125-C126
Author(s):  
N. Lock ◽  
Y. Wu ◽  
M. Christensen ◽  
B.B. Iversen ◽  
C.J. Kepert

2019 ◽  
Vol 7 (41) ◽  
pp. 24019-24026 ◽  
Author(s):  
Jack D. Evans ◽  
Johannes P. Dürholt ◽  
Stefan Kaskel ◽  
Rochus Schmid

Molecular simulations reveal that mesoporous metal–organic frameworks display large volumetric negative thermal expansion, which has a considerable effect on mechanical stability, outlining an alternative application for these ultra-porous materials.


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