Kristallstrukturen von Chlordifluor- und Dichlorfluoressigsäure. Assoziation zu einem cyclischen Dimeren und einer stark gefalteten Kette

Schilling, Michaela; Mootz, D.

doi:10.1016/0022-1139(95)03278-l

Cited by 6 publications

(6 citation statements)

References 7 publications

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“…The molecules of CF 2 ClC(O)SH form hydrogen‐bonded cyclic dimers just as in solid CF 2 ClC(O)OH, the oxygen analogue 38. The crystal packing, as viewed along the ac plane, is shown in Figure 7.…”

Section: Resultsmentioning

confidence: 99%

Chlorodifluorothioacetic Acid, CF₂ClC(O)SH: Synthesis, Characterization, X‐ray Structure and Conformational Properties

et al. 2007

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Chlorodifluoroacetic anhydride, [CF2ClC(O)]2O, and chlorodifluoroacetyl chloride, CF2ClC(O)Cl, react with hydrogen sulfide to yield chlorodifluorothioacetic acid, CF2ClC(O)SH. This novel thiocarboxylic acid has been obtained in pure form and characterized by NMR, IR and Raman spectroscopy. By extrapolation of the vapour pressure curve, log p = 6.102–2068/T (p [bar], T [K]), the boiling point was determined to be 66(1) °C. The melting point of the pure substance is –83(2) °C. The conformational properties of the gas‐phase molecule have been studied by vibrational spectroscopy [IR (vapour), Raman (liquid)] and quantum chemical calculations [B3LYP and MP2 methods with 6‐311++G(d,p) and 6‐311++G(3df,2p) basis sets]. The most stable form has C1 symmetry with a synperiplanar (syn) orientation of the C=O double bond with respect to the S–H single bond whereas in the chlorodifluoroacetyl group the gauche orientation of the ClC–C=O moiety is preferred (gauche‐syn form). The analysis of the IR spectrum of gaseous CF2ClC(O)SH suggests the presence of two other conformations in equilibrium at room temperature. These forms have been fully characterized by high‐level quantum chemical calculations. The structure of a single crystal, grown by a miniature zone‐melting procedure using focused infrared laser radiation, was determined by X‐ray diffraction analysis at low temperature. The crystalline solid [monoclinic, space group C2/c, a = 17.6165(14), b = 5.8848(5), c = 11.0877(9) Å, β = 113.5330(11)°] consists exclusively of molecules adopting the gauche‐syn conformation. These molecules associate, forming pairs of cyclic dimers in the crystal through S–H···O=C hydrogen bonds.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

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Section: Resultsmentioning

confidence: 99%

Chlorodifluorothioacetic Acid, CF₂ClC(O)SH: Synthesis, Characterization, X‐ray Structure and Conformational Properties

et al. 2007

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“…Of two carboxylic acids with similar residuals, CClF 2 COOH forms dimers in crystals, and CCl 2 FCOOH molecules aggregate into strongly folded chains [syn-syn] H-bonded with the s angles equal alternately 72, 171, À72 and À171 . 15 Of another analogous carboxylic acid, CHCl 2 COOH, only the crystal built of [syn-syn, 0 ] H-bonded dimers was obtained. 16 Some of the crystal structures of halogenated analogues of acetic acid have already been predicted using computational methods.…”

Section: Introductionmentioning

confidence: 99%

Pressure-controlled aggregation in carboxylic acids. A case study on the polymorphism of bromochlorofluoroacetic acid

2009

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Pressure induces different hydrogen-bonding patterns in the polymorphs of bromochlorofluoroacetic acid, CBrClFCOOH, by affecting the balance between secondary intermolecular interactions involving halogen and oxygen atoms. In polymorph a a pattern of the molecules syn-syn H-bonded into catemers is strongly corrugated, up to the limit imposed by steric hindrances between the neighboring chain members, whereas in polymorph b the molecules are H-bonded into dimers. No phase transition between the catemeric and dimeric CBrClFCOOH polymorphs, despite the over-pressurizing phase a by over 1.3 GPa into the stability region of phase b, demonstrates that the preference for dimeric and catemeric forms of carboxylic acids may be impossible for detection as classical solid-state phase transitions, without completely dissolving or melting these compounds and avoiding their nucleation. The smaller volume of the b phase, and hence its high-pressure stability, has been rationalized by more freedom of the 0-D dimers to adjust their positions in the crystal structure, compared to the 1-D catemers. The conformational limitations of the carboxylic-acid aggregates are consistent with the survey of all carboxylic-acid structures determined so far.

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“…Pressure was already applied to study simple carboxylic acids: in formic acid at 0.8 GPa and acetic acid at 0.2 GPa the molecules are arranged in infinite hydrogenbonded chains (Allan & Clark, 1999a,b). It was also established that relatively small substitution changes in the molecules of carboxylic acids CClF 2 COOH and CCl 2 FCOOH can lead to significant changes in the molecular association into dimers and tetramers, respectively (Schilling & Mootz, 1995).…”

Section: Introductionmentioning

confidence: 99%

Compressed hydrogen-bond effects in the pressure-frozen chloroacetic acid

Gajda¹,

Katrusiak²

2007

Acta Crystallogr Sect B

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The competing effects of squeezed OH...O bonds, destabilizing the H-atom position, and of displaced hydrogen donor and acceptor groups, favouring the ordered H-atom sites, have been tuned by pressure in the pressure-frozen dichloroacetic acid. Its structure has been determined at 0.1, 0.7, 0.9 and 1.4 GPa: in this pressure range the crystals are stable in the monoclinic space group P2(1)/n. The molecules are O-H...O hydrogen bonded into dimers, which in turn interact via a unique pattern of halogen...halogen contacts. Between 0.1 and 1.4 GPa the OH...O bond is squeezed from 2.674 (13) to 2.632 (9) A. Within the pressure range investigated the hydrogen bonds are squeezed and the shear displacement of the molecules compensate, and the H atoms remain ordered.

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Kristallstrukturen von Chlordifluor- und Dichlorfluoressigsäure. Assoziation zu einem cyclischen Dimeren und einer stark gefalteten Kette

Cited by 6 publications

References 7 publications

Chlorodifluorothioacetic Acid, CF₂ClC(O)SH: Synthesis, Characterization, X‐ray Structure and Conformational Properties

Chlorodifluorothioacetic Acid, CF₂ClC(O)SH: Synthesis, Characterization, X‐ray Structure and Conformational Properties

Pressure-controlled aggregation in carboxylic acids. A case study on the polymorphism of bromochlorofluoroacetic acid

Compressed hydrogen-bond effects in the pressure-frozen chloroacetic acid

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Kristallstrukturen von Chlordifluor- und Dichlorfluoressigsäure. Assoziation zu einem cyclischen Dimeren und einer stark gefalteten Kette

Cited by 6 publications

References 7 publications

Chlorodifluorothioacetic Acid, CF2ClC(O)SH: Synthesis, Characterization, X‐ray Structure and Conformational Properties

Chlorodifluorothioacetic Acid, CF2ClC(O)SH: Synthesis, Characterization, X‐ray Structure and Conformational Properties

Pressure-controlled aggregation in carboxylic acids. A case study on the polymorphism of bromochlorofluoroacetic acid

Compressed hydrogen-bond effects in the pressure-frozen chloroacetic acid

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Product

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Chlorodifluorothioacetic Acid, CF₂ClC(O)SH: Synthesis, Characterization, X‐ray Structure and Conformational Properties

Chlorodifluorothioacetic Acid, CF₂ClC(O)SH: Synthesis, Characterization, X‐ray Structure and Conformational Properties