Structural changes of thiourea in connection with its phase transitions: reappraisal of rigidity and libration of the molecule

Takahashi, Isao; Onodera, Akira; Shiozaki, Y.

doi:10.1107/s0108768190006012

Cited by 25 publications

(13 citation statements)

References 5 publications

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“…Perhaps in some cases pseudosymmetry went unrecognized, but it is certainly possible for a modulation to occur without a change in the space group. Consider the structures of thiourea at room temperature (Tanisaki et al, 1988) and at 170 K (Takahashi et al, 1990): the space group is Pbnm (#62) at both temperatures, but with cooling there is a ninefold expansion of the c axis. Another example is XOJYEC (McKellar et al, 2014), which undergoes a threefold modulation with cooling from 273 to 218 K while remaining in space group P1.…”

Section: Tablementioning

confidence: 99%

High-Z′ structures of organic molecules: their diversity and organizing principles

Brock

2016

Acta Crystallogr B Struct Sci Cryst Eng Mater

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Synopsis: (text) 1. Re: Structures found in the Z'  4 searches (1 pg.; pg. 3). 2. Re: The rejected structures (6 pp.; starts on pg. 4). 3. Re: XY, X = I, Br, Cl; Y = N, O interactions (3 pp.; starts on pg. 10). 4. Re: Complications (4 pp.; starts on pg. 13). 5. Re: Molecular conformations vary little (2 pp.; starts on pg. 17). 6. Re: Two or more H-bonding patterns (3 pp.; starts on pg. 19). 7. Re: Distortions from higher symmetry without an accompanying modulation are uncommon (4 pp.; starts on pg. 22). 8. Re: Sohncke groups are more frequent (1 pg.; pg. 26). 9. Re: There are usually several structural features that each double or triple Z' (2 pp.; starts on pg. 27). 10. Re: Packing units (2 pp.; starts on pg. 29). 11. Re: Ordered faults (5 pp.; starts on pg. 31). 12. Re: Phase sequences (5 pp.; starts on pg. 36). 13. Illustration of an intermediate, hybrid, phase (1 pg.; pg. 41). 14. Re: Polymorphs (7 pp.; starts on pg. 42). 15. Literature citations for the 284 structures in the final list (15 pp.; starts on pg. 49).

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Section: Tablementioning

confidence: 99%

High-Z′ structures of organic molecules: their diversity and organizing principles

Brock

2016

Acta Crystallogr B Struct Sci Cryst Eng Mater

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“…0. The pertinent data for individual planes at E pzc are as follows: 5.8 · 10 14 , 5.2 · 10 14 and 3.2 · 10 14 mol cm À2 for Cu(1 1 1), Cu(1 0 0) and Cu(1 1 0) planes and are different than that estimated from the cross-sectional areas of TU molecule calculated using crystallographic data on the distances and angles of TU molecules [45]. Assuming closed-packed monolayer and the rigid structure of the TU molecule, the C lim are equal to 4.3 · 10 14 and 6.1 · 10 14 mol cm À2 for parallel and perpendicular orientation of the adsorbate on the electrode surface, respectively [25].…”

Section: Radiometric Measurementsmentioning

confidence: 99%

Influence of the copper electrode structure on adsorption of thiourea in neutral solution

Łukomska

Sobkowski

2006

Journal of Electroanalytical Chemistry

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“…It appears that both the solid-state synthesis of thiuronium salts and their cyclization to give various 2-aminothiazoles Iminium Salts in Solid-State Syntheses Giving 100% Yield ___________________________________________________________________________ FULL PAPER Fig. 1 9 µm AFM topographies on (001) of thiourea (Pbnm) [9] with tiny (150 µg) crystallites of phenacylbromide on top at 0.5 mm distance from the contact edge; a) fresh; b) after 4 min; c) after 11 min; d) after 53 min reaction; the molecules 1a moved from right to left; tip and crystallite were aligned in the a-direction of the crystal. hexanedione or dimedone and dehydracetic acid 15 can be reacted in the solid-state with aniline derivatives.…”

Section: Enamine Ketonesmentioning

confidence: 99%

Iminium Salts in Solid-State Syntheses Giving 100% Yield

Kaupp¹,

Schmeyers

Boy

2000

J. prakt. Chem.

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269Organic reactions that give 100% yield and do not require workup are environmentally benign and particularly versatile. Their use should also be considered if highly sensitive reagents and products are involved. Indeed, waste-free reactions occur frequently in solidstate iminium salt chemistry [1]. Mechanistic knowledge from supermicroscopic investigations (AFM and SNOM) verify three-step mechanisms that consist of phase rebuilding, phase transformation and crystal disintegration in solid-state reactions without liquid phase and far-reaching anisotropic molecular movements. It is thus comprehensible that gas-solid and solid-solid reactions tend to be complete and selective with the aid of crystal packing effects. It is essential that mechanical treatment (grinding, milling, ultrasound) reestablish fresh contacts of reacting crystals over and over again for the completion of solid-solid reactions to occur [2]. Anyhow, solid-state reactions have not yet been included in organic textbooks despite repeated reports on their environmental benefits and their superior practicability due to the avoidance of work-up and wastes [3,4,5]. Anyhow, many published examples using commonly available reagents in stoichiometric quantities would deserve such inclusion, because they are particularly easy, save work and energy and are just better, if they give 100% yield without workup. Even liquids can be solidified in various instances by cooling or complexa-Abstract. Numerous reaction types in the field of iminium salts are performed in the gas-solid and solid-solid techniques in order to reach 100% yield. The stoichiometric runs are waste-free and do not require costly workup. Frequently, iminium salts were avoided, as acid catalysis was dispensable. Thioureas and α-halogenated ketones give a variety of 2-aminothiazoles via thiuronium salts in quantitative yield. A new intramolecular solid-state thermal condensation is reported. Enaminoketones are synthesized quantitatively from anilines and 1,3-diketones without catalysis and those can be used for quantitative solid-state 4-cascade reactions. Solid paraformaldehyde is used to produce methylene imines and internally trapped methylene iminium salts. Benzoylhydrazones are produced again without catalysis in the solid state. Vacuum and ball-mill techniques are particularly useful in the production

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Structural changes of thiourea in connection with its phase transitions: reappraisal of rigidity and libration of the molecule

Cited by 25 publications

References 5 publications

High-Z′ structures of organic molecules: their diversity and organizing principles

High-Z′ structures of organic molecules: their diversity and organizing principles

Influence of the copper electrode structure on adsorption of thiourea in neutral solution

Iminium Salts in Solid-State Syntheses Giving 100% Yield

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