380. The crystal and molecular structure of tetraethylammonium iodide

Wait, E.; Powell, H. M.

doi:10.1039/jr9580001872

Cited by 43 publications

(22 citation statements)

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“…The crystal structure of the Et 4 N + iodide salt shows the S 4 conformation, 2,5 while in the crystallographic study of the Et 4 N + bromide salt the D 2d conformation is observed. 9 The recent database analysis 1 had shown that the S 4 and D 2d conformers of Et 4 N + are observed in the ratio of 45 : 163 (0.28) in 208 different molecular complexes.…”

Section: Discussionmentioning

confidence: 94%

“…Considerable efforts have been devoted to studies of the structure, thermodynamics and solution properties of these compounds. [1][2][3][4][5][6][7][8][9][10] A general postulate is that conformations of hydrocarbon chains in tetra n-alkylammonium ions are controlled by quaternary centre. The observed conformational pattern is thus explained by steric intramolecular interactions between the carbon atoms in the second and more distant positions from the central nitrogen atom, in which case the avoidance of unfavourable g + g À interactions is important.…”

Section: Introductionmentioning

confidence: 99%

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Computational and NMR study of quaternary ammonium ion conformations in solution

Luzhkov

Österberg

Acharya

et al. 2002

Phys. Chem. Chem. Phys.

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Conformations around C-N bonds at the quaternary centre in tetraalkylammonium ions in water solution are investigated. Structures of Me 4 N + , Et 4 N + , n-Pr 4 N + , n-Bu 4 N + , and n-Pe 4 N + are calculated using quantum mechanical HF and DFT methods together with the PCM solvent model. Relative solvation free energies of tetraalkylammonium ions are further estimated from microscopic molecular dynamics free energy perturbation simulations using the Gromos-87 and Amber-95 force fields. The predicted free energy difference in solution between two stable conformations of Et 4 N + , D 2d and S 4 , is 0.6-1.0 kcal mol À1 (in favour of D 2d ), which is in quantitative agreement with the recent Raman spectroscopy results. The energies of the g + g À conformations of Et 4 N + are 3.6-4.0 kcal mol À1 higher. The ions with longer hydrocarbon chains show quite similar energy gap between D 2d and S 4 . The torsion barrier for a two-step interconversion between the D 2d and S 4 structures is 9.5 kcal mol À1 (HF/6-31G(d) calculations). The computational results are augmented by NMR measurements of the Et 4 N + -I À salt in aqueous solution, which predict a symmetric structure of Et 4 N + in water. However, the D 2d and S 4 conformers are not discernible due to presumably high similarity of chemical shifts. The calculated conformational energetics in solution together with previously observed D 2d , S 4 and high-energy g + g À -type structures of Et 4 N + , n-Pr 4 N + , and n-Bu 4 N + in the solid state indicate that the carbon chain conformations at the quaternary ammonium centre sensitively depend on the actual microenvironment.

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Section: Discussionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Computational and NMR study of quaternary ammonium ion conformations in solution

Luzhkov

Österberg

Acharya

et al. 2002

Phys. Chem. Chem. Phys.

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“…This value can be ascribed to tumbling or diffusion of the bulky liquid-like species. The crystal structures of tetraalkylammonium halides have been determined for tetraethylammonium iodide [10], tetrapropylammonium bromide [11] and iodide [12] and tetrabutylammonium bromide and iodide [13]. The structures of the respective cations due to their static packing disorder and the lack of the proton location cannot be used for theoretical calculation of the interproton interactions and thus respective second moments values.…”

Section: Discussionmentioning

confidence: 99%

Molecular Motion in Solid Tetradecylammonium Bromide

Szafrańska

̧k

1998

phys. stat. sol. (a)

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“…2. However, the coordinates of C (2) given there appear to correspond to C (2) attachedtoC(l)(i + y , i -x , i -z)andnottoC(l)withx,y,z of Table 2.…”

Section: E T Amentioning

confidence: 99%

Crystal chemistry of tetraradial species. Part 2. Crystal structures of Et₄NI, Ph₄PBr•H₂O, and Ph₄PBr•2H₂O

Vincent¹,

Knop²,

Linden³

et al. 1988

Can. J. Chem.

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The crystal structure of Et4NI (14,a = 8,860(2) A, c = 6.932() A, Z = 2) has been redetermined and those of Ph4PBr.H20 ( p i , n = 10.005(3) A, b = 10.659(2) A, c = 10.697(4) A, % = 102.61(2)", P = 83.39(3)", y = 108.09(3)", Z = 2) and Ph4PBr.2H20 (Pnma, a = 16.255(4) A, b = 10.810(4) A, c = 12.667(9) A, Z = 4) have been determined for the first time. In the Et4NI structure Et4Nt cations in an extended S4 conformation and I-anions are arranged in a zincblende-type packing. The two hydrate structures are ionic and very similar. The anion in the monohydrate is a centrosymmetric cyclic dimer [Br2(0~2)2]2-; in the dihydrate the anion, which is an almost planar infinite 412]z chain Ilb, appears to be of a novel type. If the H20 molecules are not considered, the ion packing in both hydrates may be regarded as of the anti-NiAs type. The ion packing in R4EX structures and the conformation of the Et4N+ ion in crystals are discussed in some detail. In this series of investigations we are interested in discovering how the idealized symmetry (Td or subgroup) of tetraradial" XL: ' species is reflected in the crystallographic symmetry when XL2' is incorporated in a crystal, on its own (n = 0) or in combination with another, not necessarily tetraradial species, and in particular how the packing type is affected by the size and complexity of XLI;' in simple chemical combinations. In the present contribution to the systematic crystal chemistry of such species we report the results of a redetermination of the structure of Et4NI and of determinations of the structures of Ph4PBr.H20 and Ph4PBr.2H20. Although Ph4PBr rather than its hydrates was originally the compound to be investigated, we were unsuccessful in our attempts to obtain crystals of the anhydrous bromide (see ~xperimental) .5

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380. The crystal and molecular structure of tetraethylammonium iodide

Cited by 43 publications

References 0 publications

Computational and NMR study of quaternary ammonium ion conformations in solution

Computational and NMR study of quaternary ammonium ion conformations in solution

Molecular Motion in Solid Tetradecylammonium Bromide

Crystal chemistry of tetraradial species. Part 2. Crystal structures of Et₄NI, Ph₄PBr•H₂O, and Ph₄PBr•2H₂O

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380. The crystal and molecular structure of tetraethylammonium iodide

Cited by 43 publications

References 0 publications

Computational and NMR study of quaternary ammonium ion conformations in solution

Computational and NMR study of quaternary ammonium ion conformations in solution

Molecular Motion in Solid Tetradecylammonium Bromide

Crystal chemistry of tetraradial species. Part 2. Crystal structures of Et4NI, Ph4PBr•H2O, and Ph4PBr•2H2O

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Crystal chemistry of tetraradial species. Part 2. Crystal structures of Et₄NI, Ph₄PBr•H₂O, and Ph₄PBr•2H₂O