Manifestation of Stereoelectronic Effects on the Calculated Carbon−Hydrogen Bond Lengths and One-Bond1JC-HNMR Coupling Constants. Relative Acceptor Ability of the Carbonyl (CO), Thiocarbonyl (CS), and Methylidene (CCH2) Groups toward C−H Donor Bonds

The conformational preferences in CCl4 solution at 32 °C of the hydroxyl groups in bromine derivatives of 1,3-dihydroxybenzene are deduced from the long-range spin–spin coupling constants between hydroxyl protons and ring protons over five bonds. Two hydroxyl groups hydrogen bond to the same bromine substituent in 2-bromo-1,3-dihydroxybenzene but prefer to hydrogen bond to different bromine substituents when available, as in 2,4-dibromo-1,3-dihydroxybenzene. When the OH groups can each choose between two ortho bromine atoms, as in 2,4,6-tribromoresorcinol, they apparently do so in a very nearly statistical manner except that they avoid hydrogen bonding to the common bromine atom.

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Intramolecular hydrogen bond investigations in some Schiff bases using C–C and N–C coupling constants

Journal of Molecular Structure ◽

10.1016/j.molstruc.2003.10.043 ◽

2004 ◽

Vol 689 (3) ◽

pp. 245-249 ◽

Cited By ~ 20

Author(s):

Wojciech Schilf

Keyword(s):

Hydrogen Bond ◽

Schiff Bases ◽

Intramolecular Hydrogen Bond ◽

Coupling Constants ◽

C And N ◽

Intramolecular Hydrogen

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Hydrogen Bond Studies. 125. A Deuteron Magnetic Resonance Study of Strontium Formate Dihydrate, Sr(HCOO)2 · 2D2O

Zeitschrift für Naturforschung A ◽

10.1515/zna-1977-0918 ◽

1977 ◽

Vol 32 (9) ◽

pp. 1025-1029 ◽

Cited By ~ 5

Author(s):

Bo Berglund ◽

Jörgen Tegenfeldt

Keyword(s):

Crystal Structure ◽

Hydrogen Bond ◽

Magnetic Resonance ◽

Electric Field Gradient ◽

Room Temperature ◽

Coupling Constants ◽

Water Molecules ◽

Magnetic Resonance Study ◽

Quadrupole Coupling ◽

Asymmetry Parameters

AbstractA room temperature (25 °C) deuteron magnetic resonance (DMR) study of a single crystal of Sr (HCOO)2 · 2 D2O is reported. Signals from all water molecules in the unit cell have been detected, and all four independent electric field gradient (EFG) tensors at the water deuterons have been determined from 409 quadrupole splittings. All spectra were recorded by rotating the crystal about one arbitrarily selected axis. The following quadrupole coupling constants and asymmetry parameters for the deuterons were obtained: 213.5(4), 189.3(4), 195.7(4) and 200.7(5) kHz and 0.117(3), 0.110(4), 0.116(4) and 0.098(3). The directions of the eigenvalues are qualitatively consistent with the crystal structure refined by Galigné 1; the result is in disagreement, however, with the earlier DMR study of Sr (DCOO)2 · 2 D2O (Reference 2).

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Polysulfonylamine, CLXXXIX [1]. Weitere Beispiele für die O-Protonierung von Harnstoffen mit Di(organosulfonyl)aminen: Bildung und Kristallstrukturen von 1,1-Dimethyluroniumdi( 4-fluorbenzolsulfonyl)amid und Di(1-methylharnstoff)- hydrogen(I)-di(4-fluorbenzolsulfonyl)amid/ Polysulfonylamines, CLXXXIX. Additional Examples of the O-Protonation of Ureas by Di(organosulfonyl)amines: Formation and Crystal Structures of 1,1-Dimethyluronium Di(4-fluorobenzenesulfonyl)amide and Di(1-methylurea)hydrogen(I)Di(4-fluorobenzenesulfonyl) amide

Zeitschrift für Naturforschung B ◽

10.1515/znb-2010-1112 ◽

2010 ◽

Vol 65 (11) ◽

pp. 1363-1371 ◽

Cited By ~ 2

Author(s):

Christoph Wölper ◽

Alejandra Rodríguez-Gimeno ◽

Katherine Chulvi Iborra ◽

Peter G. Jones ◽

Armand Blaschette

Keyword(s):

Hydrogen Bond ◽

Hydrogen Bonds ◽

Proton Transfer ◽

Petroleum Ether ◽

Crystal Structures ◽

Monoclinic Space Group ◽

One Dimensional ◽

Bond Lengths ◽

Ionic Compounds ◽

Specific Elongation

Co-crystallization of N-methyl-substituted ureas with di(organosulfonyl)amines, (RSO2)2NH, leads unpredictably to either molecular co-crystals or, via proton transfer, to uronium salts. As a sequel to former reports, this communication describes the formation and the crystal structures of the new ionic compounds 1,1-dimethyluronium di(4-fluorobenzenesulfonyl)amide (1, monoclinic, space group P21/c, Z´ = 1) and di(1-methylurea)hydrogen(I) di(4-fluorobenzenesulfonyl)amide (2, triclinic, P1̄, Z´ = 1); both salts were obtained from dichloromethane/petroleum ether. In the structure of 2, the urea moieties of the cationic homoconjugate are connected by a very short [O-H· · ·O]+ hydrogen bond [d(O· · ·O) = 244.6(2) pm, θ (O-H· · ·O)≈170°, bridging H atom asymmetrically disordered over two positions]. The O-protonation induces a specific elongation of the C-O bond lengths to 131.2(2) pm in 1 or 129.5(2) and 127.4(2) pm in 2, as compared to literature data of ca. 126 pm for the unprotonated ureas. Both crystal structures are dominated by conventional two- and threecentre hydrogen bonds, which involve the OH and all NH donors and give rise to one-dimensional cation-anion arrays. In particular, the ionic entities of 1 are alternatingly associated into simple chains propagated by glide-plane operations parallel to the c axis, whereas the donor-richer structure of 2 displays inversion symmetric dimers of formula units, which are further hydrogen-bonded into strands propagated by translation parallel to the a axis.

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