Nuclear Shielding of the Transition Metals

Kidd, R. G.

doi:10.1016/s0066-4103(08)60392-0

Cited by 68 publications

(17 citation statements)

References 130 publications

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“…This is due to the formation of silver complexes with electron donating solvents [23,45], which results in significant shifts of the 109 Ag and, to some extent, the 14 N NMR resonances. Similar large shielding variations have been observed in 109 Ag NMR spectra of silver halides in S/N/O-bonded ligands, but not, as in this case, to a complex anion, such as the trinitromethanide anion [46].…”

Section: Synthesis and Spectroscopic Characterizationssupporting

confidence: 82%

Structures of Energetic Acetylene Derivatives HC≡CCH₂ONO₂, (NO₂)₃CCH₂C≡CCH₂C(NO₂)₃ and Trinitroethane, (NO₂)₃CCH₃

Klapötke

Krumm

Moll

et al. 2013

Zeitschrift Für Naturforschung B

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The molecular structures and relative ratios of the two conformers (anti and gauche) of HCCCH 2 ONO 2 detected in the gas phase at room temperature have been determined by electron diffraction. The results are discussed on the basis of quantum chemical calculations. The molecular structures of (NO 2 ) 3 CCH 2 C≡CCH 2 C(NO 2 ) 3 and (NO 2 ) 3 CCH 3 have been determined by X-ray diffraction. A 109 Ag NMR study was performed for silver trinitromethanide Ag[C(NO 2 ) 3 ] in various polar solvents.

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Section: Synthesis and Spectroscopic Characterizationssupporting

confidence: 82%

Structures of Energetic Acetylene Derivatives HC≡CCH₂ONO₂, (NO₂)₃CCH₂C≡CCH₂C(NO₂)₃ and Trinitroethane, (NO₂)₃CCH₃

Klapötke

Krumm

Moll

et al. 2013

Zeitschrift Für Naturforschung B

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“…Such effects are known to overcompensate for the trends caused by decreasing electronegativity for the heavier halogen substituents. 38 Indeed, employing the two-component relativistic zeroth-order regular approximation (ZORA) method within the ADF code, in order to account for the SO corrections to the 11 B shifts in the B(9) and B(12) positions for 2, improves the fit between theory and experiment for these atoms considerably (SO contributions amounts to ca. 21 ppm for all three geometries considered), as Table 2 also shows.…”

Section: Resultsmentioning

confidence: 99%

Influence of Antipodally Coupled Iodine and Carbon Atoms on the Cage Structure of 9,12-I₂-closo-1,2-C₂B₁₀H₁₀: An Electron Diffraction and Computational Study

et al. 2015

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Because of the comparable electron scattering abilities of carbon and boron, the electron diffraction structure of the C2v-symmetric molecule closo-1,2-C2B10H12 (1), one of the building blocks of boron cluster chemistry, is not as accurate as it could be. On that basis, we have prepared the known diiodo derivative of 1, 9,12-I2-closo-1,2-C2B10H10 (2), which has the same point-group symmetry as 1 but in which the presence of iodine atoms, with their much stronger ability to scatter electrons, ensures much better structural characterization of the C2B10 icosahedral core. Furthermore, the influence on the C2B10 geometry in 2 of the antipodally positioned iodine substituents with respect to both carbon atoms has been examined using the concerted application of gas electron diffraction and quantum chemical calculations at the MP2 and density functional theory (DFT) levels. The experimental and computed molecular geometries are in good overall agreement. Molecular dynamics simulations used to obtain vibrational parameters, which are needed for analyzing the electron diffraction data, have been performed for the first time for this class of compound. According to DFT calculations at the ZORA-SO/BP86 level, the (11)B chemical shifts of the boron atoms to which the iodine substituents are bonded are dominated by spin-orbit coupling. Magnetically induced currents within 2 have been calculated and compared to those for [B12H12](2-), the latter adopting a regular icosahedral structure with Ih point-group symmetry. Similar total current strengths are found but with a certain anisotropy, suggesting that spherical aromaticity is present; electron delocalization in the plane of the hetero atoms in 2 is slightly hindered compared to that for [B12H12](2-), presumably because of the departure from ideal icosahedral symmetry.

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“…The computed 71 Ga chemical shifts forc hlorogallium complexes[ Ga(NH 3 ) n Cl 6Àn ] (nÀ3) + (n = 3-5) are quite similaro r-in case of trans-[Ga(NH 3 ) 4 Cl 2 ] + and fac/mer-[Ga(NH 3 ) 3 Cl 3 ]-slightly larger than that of the "naked" hexaamminec omplex, whereas the chemical shifts of the homologous bromo-and iodo-complexes are substantially lower and tend to become increasingly more negative with growing atomics ize (thus showing a normalh alogen dependence and number of halide ligands). [27] An inspectiono fi ndividual shielding contributions reveals that the differentialc hanges in d 71 Ga calcd for complexes containing exclusively amine-/amide-and chloride-basedl igands depend mainly on variations in the paramagnetic shielding term, [28] whereas the trends in complexes with metal-bound bromide and iodide ions are dominated by spin-orbit effects. [23] Quite surprising, incorporation of halide ligands into the first coordination sphere induces in most cases no sharp increasei nt he magnitude of q zz 2 ,w hichi mplies that the effective local elec-tron density distribution around the metal ion remains quite symmetrical.…”

Section: Resultsmentioning

confidence: 99%

Approaching Dissolved Species in Ammonoacidic GaN Crystal Growth: A Combined Solution NMR and Computational Study

Becker

Wonglakhon

Zahn

et al. 2020

Chemistry A European J

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Solutionso fg allium trihalidesG a X 3 (X = F, Cl, Br,I ) and their ammoniatesi nl iquid ammonia were studied at ambient temperature under autogenousp ressure by multinuclear ( 71 Ga, 35 Cl, 81 Br) NMR spectroscopy.T ou nravel the role of pH, the analysesw ere done both in absence and in presence of ammonium halides, which are employed as mineralizers during ammonoacidic gallium nitride crystal growth. While gallium trifluoride and its ammoniate were found to be too sparingly soluble to give rise to aN MR signal, the spectra of solutions of the heavier halides reveal the presence of as ingle gallium-containing species in all cases. DFT calculations and molecular dynamics simulations suggest the identification of this species as consisting of a [Ga(NH 3 ) 6 ] 3 + cation and up to six surrounding halide anions, resultingi na no verall trend towards negative complex charge. Quantitative 71 Ga NMR studies on saturated solutions of GaCl 3 containing variousa mountso fa dditional NH 4 Cl revealed an ear linear increase of GaCl 3 solubility with mineralizer concentrationo fa bout 0.023 mol GaCl 3 per mol NH 4 Cl at room temperature. These findings reflect the importance of Coulombic shielding fort he inhibition of oligomerization and precipitation processes and help to rationalize both the low solubility of gallium halides in neutral ammonia solution and, in turn, the proliferating effect of the mineralizer during ammonoacidic gallium nitride formation.

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Nuclear Shielding of the Transition Metals

Cited by 68 publications

References 130 publications

Structures of Energetic Acetylene Derivatives HC≡CCH₂ONO₂, (NO₂)₃CCH₂C≡CCH₂C(NO₂)₃ and Trinitroethane, (NO₂)₃CCH₃

Structures of Energetic Acetylene Derivatives HC≡CCH₂ONO₂, (NO₂)₃CCH₂C≡CCH₂C(NO₂)₃ and Trinitroethane, (NO₂)₃CCH₃

Influence of Antipodally Coupled Iodine and Carbon Atoms on the Cage Structure of 9,12-I₂-closo-1,2-C₂B₁₀H₁₀: An Electron Diffraction and Computational Study

Approaching Dissolved Species in Ammonoacidic GaN Crystal Growth: A Combined Solution NMR and Computational Study

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Nuclear Shielding of the Transition Metals

Cited by 68 publications

References 130 publications

Structures of Energetic Acetylene Derivatives HC≡CCH2ONO2, (NO2)3CCH2C≡CCH2C(NO2)3 and Trinitroethane, (NO2)3CCH3

Structures of Energetic Acetylene Derivatives HC≡CCH2ONO2, (NO2)3CCH2C≡CCH2C(NO2)3 and Trinitroethane, (NO2)3CCH3

Influence of Antipodally Coupled Iodine and Carbon Atoms on the Cage Structure of 9,12-I2-closo-1,2-C2B10H10: An Electron Diffraction and Computational Study

Approaching Dissolved Species in Ammonoacidic GaN Crystal Growth: A Combined Solution NMR and Computational Study

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Structures of Energetic Acetylene Derivatives HC≡CCH₂ONO₂, (NO₂)₃CCH₂C≡CCH₂C(NO₂)₃ and Trinitroethane, (NO₂)₃CCH₃

Structures of Energetic Acetylene Derivatives HC≡CCH₂ONO₂, (NO₂)₃CCH₂C≡CCH₂C(NO₂)₃ and Trinitroethane, (NO₂)₃CCH₃

Influence of Antipodally Coupled Iodine and Carbon Atoms on the Cage Structure of 9,12-I₂-closo-1,2-C₂B₁₀H₁₀: An Electron Diffraction and Computational Study