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51.
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Gemma F. Turner Scott C. McKellar David R. Allan Anthony K. Cheetham Sebastian Henke Stephen A. Moggach 《Chemical science》2021,12(41):13793
The guest-dependent flexibility of the pillared-layered metal–organic framework (MOF), Zn2bdc2dabco·X(guest), where guest = EtOH, DMF or benzene, has been examined by high-pressure single crystal X-ray diffraction. A pressure-induced structural phase transition is found for the EtOH- and DMF-included frameworks during compression in a hydrostatic medium of the guest species, which is dependent upon the nature and quantity of the guest in the channels. The EtOH-included material undergoes a phase transition from P4/mmm to C2/m at 0.69 GPa, which is accompanied by a change in the pore shape from square to rhombus via super-filling of the pores. The DMF-included material undergoes a guest-mediated phase transition from I4/mcm to P4/mmm at 0.33 GPa via disordering of the DMF guest. In contrast, the benzene-included framework features a structure with rhombus-shaped channels at ambient pressure and shows direct compression under hydrostatic pressure. These results demonstrate the large influence of guest molecules on the high-pressure phase behavior of flexible MOFs. Guest-mediated framework flexibility is useful for engineering MOFs with bespoke pore shapes and compressibility.The guest-dependent flexibility of the pillared-layered metal–organic framework (MOF), Zn2bdc2dabco·X(guest), where guest = EtOH, DMF or benzene, has been examined by high-pressure single crystal X-ray diffraction. 相似文献
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Rodriguez EE Poineau F Llobet A Kennedy BJ Avdeev M Thorogood GJ Carter ML Seshadri R Singh DJ Cheetham AK 《Physical review letters》2011,106(6):067201
We present evidence for possibly the highest magnetic ordering temperature in any compound without 3d transition elements. Neutron powder diffraction measurements, at both time-of-flight and constant wavelength sources, were performed on two independently prepared SrTcO3 powders. SrTcO3 adopts a distorted perovskite structure with G-type antiferromagnetic ordering and has a moment of 1.87(4)μB per Tc cation at room temperature with an extraordinarily high Néel point close to 750 °C. Electronic structure calculations reveal extensive mixing between the technetium 4d states and oxygen states proximal to the Fermi level. This hybridization leads to a close relationship between magnetic ordering temperature and moment formation in SrTcO3. 相似文献
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Thierry Loiseau Sharma Neeraj Anthony K. Cheetham 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(7):m379-m381
Crystals of gallium fluorophenylphosphonate were synthesized hydrothermally at 453 K under autogenous pressure. The solid crystallizes in the monoclinic system and its structure is built up by the connection of zigzag chains of edge‐sharing GaO4F2 octahedra to phenylphosphonate groups. This results in the formation of a layered structure, in which the phenyl groups point upward and downward from the inorganic sheet. The Ga atoms occupy the special positions 4a (inversion center) and 4e (twofold axis). 相似文献
59.
M Pattabiraman G Rangarajan Kwang-Yong Choi P Lemmens G Guentherodt G Balakrishnan DMcK Paul MR Lees 《Pramana》2002,58(5-6):1013-1017
We report polarized Raman scattering in single crystals of Nd0.7Sr0.3MnO3. The temperature dependence of the MnO6 octahedral bending and stretching modes observed in the XX spectra points to the existence of local lattice distortions,
possibly polarons. The XY spectra have been analyzed using a collision-dominated model, which allows the extraction of the
carrier scattering rate. 相似文献
60.
Experimental observations are reported of the nonlinear interaction of two torsional hydromagnetic waves propagating in opposite directions in a cylindrical plasma waveguide. 相似文献