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This study successfully implemented microcrystal electron diffraction (microED) and X-ray powder diffraction (XRPD) for the crystal structure determination of a new phase, TAF-CNU-1, Ni(C8H4O4)·3H2O, solved by microED from single microcrystals in the powder and refined at the kinematic and dynamic electron diffraction theory levels. This nickel metal–organic framework (MOF), together with its cobalt and manganese analogues with formula M(C8H4O4)·2H2O with M = MnII or CoII, were synthesized in aqueous media as one-pot preparations from the corresponding hydrated metal chlorides and sodium terephthalate, as a promising ‘green’ synthetic route to moisture stable MOFs. The crystal structures of the two latter materials have been previously determined ab initio from X-ray powder diffraction. The advantages and disadvantages of both structural characterization techniques are briefly summarized. Additional solid-state property characterization was carried out using thermogravimetric analysis, scanning electron microscopy and Fourier transform infrared spectroscopy.
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True molecular conformation and structure determination by three-dimensional electron diffraction of PAH by-products potentially useful for electronic applications
The true molecular conformation and the crystal structure of benzo[ e ]dinaphtho[2,3- a ;1′,2′,3′,4′- ghi ]fluoranthene, 7,14-diphenylnaphtho[1,2,3,4- cde ]bisanthene and 7,16-diphenylnaphtho[1,2,3,4- cde ]helianthrene were determined ab initio by 3D electron diffraction. All three molecules are remarkable polycyclic aromatic hydrocarbons. The molecular conformation of two of these compounds could not be determined via classical spectroscopic methods due to the large size of the molecule and the occurrence of multiple and reciprocally connected aromatic rings. The molecular structure of the third molecule was previously considered provisional. These compounds were isolated as by-products in the synthesis of similar products and were at the same time nanocrystalline and available only in very limited amounts. 3D electron diffraction data, taken from submicrometric single crystals, allowed for direct ab initio structure solution and the unbiased determination of the internal molecular conformation. Detailed synthetic routes and spectroscopic analyses are also discussed. Based on many-body perturbation theory simulations, benzo[ e ]dinaphtho[2,3- a ;1′,2′,3′,4′- ghi ]fluoranthene may be a promising candidate for triplet–triplet annihilation and 7,14-diphenylnaphtho[1,2,3,4- cde ]bisanthene may be a promising candidate for intermolecular singlet fission in the solid state.
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- Award ID(s):
- 2021803
- PAR ID:
- 10402593
- Date Published:
- Journal Name:
- IUCrJ
- Volume:
- 10
- Issue:
- 1
- ISSN:
- 2052-2525
- Page Range / eLocation ID:
- 131 to 142
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1107/S205225252201154X
