Direct chlorocarbon.cntdot..cntdot..cntdot.calcium(2+) binding: crystal structure of calcium chloroacetate hydrate

Karipides, A.; Peiffer, K.

doi:10.1021/ic00291a048

Cited by 6 publications

(5 citation statements)

References 4 publications

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“…The chloroacetates of silver, lead, thallium(I), mercury(II), and copper(II) 41 were synthesized by acid−base reactions in water or ethanol. Calcium chloroacetate monohydrate was synthesized both from ethanol and water and gave the NQR spectrum reported earlier by Guibé; TGA analysis confirmed that the product obtained was actually the monohydrate, the crystal structure of which has been determined . Silver chloroacetate was also prepared by precipitation and homogeneous precipitation; although the largest crystals were produced by the latter method, there was little difference in NQR signal strength.…”

Section: Resultsmentioning

confidence: 54%

“…Large splittings are also found in a few salts and complexes of the hard acids Li + , Na + , H + , Ba 2+ , (C 5 H 5 ) 2 Zr 2+ , and (C 5 H 5 ) 2 Hf 2+ . Such hard acid-soft base interactions are found in calcium chloroacetate monohydrate 22 and in two recently reported complexes of dihaloalkanes with [Cs(tetrabenzo-24-crown-8)] + . 60 But the large splittings could alternately be due to some other chemical difference: for example, the presence of both free and coordinated anions in the same structure.…”

Section: Weakly Coordinating Trichloromethanesulfonate Anionmentioning

confidence: 66%

“…Calcium chloroacetate monohydrate was synthesized both from ethanol and water and gave the NQR spectrum reported earlier by Guibe ´; TGA analysis confirmed that the product obtained was actually the monohydrate, the crystal structure of which has been determined. 22 Silver chloroacetate was also prepared by precipitation 42 and homogeneous precipitation; 22 although the largest crystals were produced by the latter method, there was little difference in NQR signal strength. Cu 2 (ClCH 2 CO 2 ) 4 ‚ 5H 2 O dissolved in methanol was reacted with the chemical dehydrating reagent 2,2-dimethoxypropane for 2 days: the crystals that were obtained still showed the IR bands of water and analyze approximately to be the known dihydrate.…”

Section: Resultsmentioning

confidence: 99%

“…Silver chloroacetate has a typical type III dimeric structure, but there are also interdimer contacts between each chlorine in one dimer and a silver atom in another; such a feature is absent in silver fluoroacetate . In calcium chloroacetate monohydrate conformational changes result in halogen−metal ion contact and a nonlayer overall structure. We have previously shown that organohalogen coordination to metals such as silver profoundly affects their 35 Cl NQR frequencies. ,, Hence NQR data for soft-acid metal ion salts of chlorinated anions (and calcium chloroacetate) must be analyzed separately; these will be the focus of a separate study.…”

Section: Introductionmentioning

confidence: 99%

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The Weakly Coordinating Trichloromethanesulfonate Anion: NQR Comparison of Its Coordinating Abilities via Oxygen with Those of the Chloroacetate Ions

et al. 2004

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Ionic and covalent derivatives of the chlorine analogue of the nonbasic, weakly coordinating triflate ion, Cl3CSO3(-) or "trichlate" ion, have been prepared and compared with the corresponding more strongly coordinated chloroacetates, Cl(x)CH(3-x)CO(2)M (x = 1-3), using 35Cl NQR (nuclear quadrupole resonance) spectroscopy. The (35)Cl NQR frequencies of all types of derivatives are sensitive to the nature of the metal ion or Lewis acid and are most sensitive in the case of monochloroacetates. In covalent (including zirconocene) derivatives, the average NQR frequencies fall as the Pauling electronegativity of M falls. The results for ionic derivatives contrast with previous results for ionic hexachlorometalates: the average (35)Cl NQR frequencies drop sharply as the ionic radius of the group 1 cation increases. Ab initio Gaussian 98 computations at the B3LYP/6-311++G(3df,3pd) level on isolated XCH2CO2M (M = Li, Na, K; X = F, Cl) molecules duplicate this trend, showing increasing polarization of the C-Cl bond and smaller electric field gradients for larger group 1 ions; the relevance of this to the solid state polymerization of chloroacetates (Herzberg, O.; Epple, M. Eur. J. Inorg. Chem. 2001, 1395-1406) is discussed. We have prepared the dihydrate and monohydrate of trichlic acid, Cl3CSO3H. Although trichlates have the highest average NQR frequencies of any of these salts, the NQR frequencies of trichlic acid dihydrate are anomalously lower than those of trichloroacetic acid, which suggests that it is a strong acid, ionized in the solid state to H5O2+ and Cl3CSO3(-) ions.

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Section: Resultsmentioning

confidence: 54%

Section: Weakly Coordinating Trichloromethanesulfonate Anionmentioning

confidence: 66%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Weakly Coordinating Trichloromethanesulfonate Anion: NQR Comparison of Its Coordinating Abilities via Oxygen with Those of the Chloroacetate Ions

et al. 2004

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“…Possibly Group 1 cation-ort/io-organochlorine interactions [4] may be involved in directing elimination of ortho-rather than para-chlorines when dioxins are formed. Using NQR spectroscopy, we can study the degree to which various +1 cations influence the solid-state electronic distribution in chlorophenolate ions.…”

Section: Introductionmentioning

confidence: 99%

Dioxin Precursors: NQR Studies of Group 1 and Related 2,6-Dichlorophenolate and 2,4,6-Trichlorophenolate Salts

Wulfsberg

Shadid

Farris

et al. 1992

Zeitschrift Für Naturforschung A

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The 81 Br and 35 C1 NQR spectra of anhydrous Group 1, tetraalkylammonium, and thallium(I) 2,6-dichlorophenolates, 2,4,6-trichlorophenolates, and 4-bromo-2,6-dichlorophenolates were searched for evidence of solid-state cation-organochlorine interactions that might, for example, be (in part) responsible for the difference in the thermal decomposition reactions of these salts (to give the supertoxic environmental pollutants, the polychlorinated dibenzodioxins) versus those of the corresponding Group 11 chlorophenolate complexes, which do not decompose to dioxins.For cations ranging in size from tetraethylammonium to potassium, the total range of 35 C1 NQR frequencies in 2,6-dichlorophenolate and 2,4,6-trichlorophenolate salts is only 1.401 MHz, which, although larger than the 0.7 MHz range likely in molecular chlorocarbons, is smaller than in individual chlorophenolates of copper(I) and silver(I) (up to 2.0 MHz). In sodium and thallium(I) 2,4,6-trichlorophenolates substantially large frequency shifts (ca. 2.0 MHz) occur, to higher frequencies for the para-chlorines and lower frequencies for the ortho-chlorines (Na only). These disappear even in closely related compounds and show a pattern that seems unrelated to the decomposition products of the chlorophenolates.

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Nuclear Quadrupole Resonance (NQR) Spectroscopy

Wulfsberg

2005

Encyclopedia of Inorganic Chemistry

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The article concerns the usefulness of nuclear quadrupole resonance (NQR) spectroscopy in inorganic and organometallic chemistry. NQR‐active nuclei have spin I ≥ 1; those of high enough abundance to be commonly useful are found in the odd‐numbered groups of the periodic table. These are tabulated and examples given for each. The number of NQR frequencies observed in a solid‐state compound reflects the number of chemically different quadrupolar atoms in the compound and also the number of crystallographically inequivalent atoms; changes in the latter may indicate phase transitions or different polymorphs of a given compound. More commonly, one uses average NQR frequencies for chemically different atoms, and from these average frequencies, derives atomic parameters such as populations of valence orbitals, partial ionic charges, π‐bond orders, and covalent bond orders of the quadrupolar atom. The article mainly reviews selected applications of halogen ( 35 Cl, 79, 81 Br, 127 I) NQR to specific bonding questions in inorganic chemistry, and divides these according to whether the halogen or other atoms are (a) single bonded, (b) single bonded but with secondary bonds with other atoms, or (c) bonded to several atoms. For singly bonded atoms, the applications reviewed include (a1) relativistic effects, (a2) effects of nearby ionic charges on haloacetate ions, (a3) the contrasting effects of nearby ionic charges on halometallate ions, (a4) effects of intramolecular partial charges on chlorines in organosilicon compounds, (a5) cis‐and trans‐ ligand effects in substituted halometallate complexes, and (a6) interpretations of multicentered bonding in trihalide ions. Secondary bonding of single‐bonded halogen atoms are reviewed particularly in the cases of (b1) halocarbons as ligands, (b2) chloroacetates and chlorophenolates as chlorine‐donor ligands, and (b3) in salts of weakly coordinated halogenated anions. Finally, some illustrations are given of NQR studies of central multicoordinated atoms (for example, transition‐metal atoms in complexes).

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Direct chlorocarbon.cntdot..cntdot..cntdot.calcium(2+) binding: crystal structure of calcium chloroacetate hydrate

Cited by 6 publications

References 4 publications

The Weakly Coordinating Trichloromethanesulfonate Anion: NQR Comparison of Its Coordinating Abilities via Oxygen with Those of the Chloroacetate Ions

The Weakly Coordinating Trichloromethanesulfonate Anion: NQR Comparison of Its Coordinating Abilities via Oxygen with Those of the Chloroacetate Ions

Dioxin Precursors: NQR Studies of Group 1 and Related 2,6-Dichlorophenolate and 2,4,6-Trichlorophenolate Salts

Nuclear Quadrupole Resonance (NQR) Spectroscopy

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