Correspondence: Hydrogen Bond to Gold? 1H NMR is Not a Proof of Hydrogen Bonds in Transition Metal Complexes

2018 ◽  
Author(s):  
Jan Vícha ◽  
Cina Foroutan-Nejad ◽  
Michal Straka
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Chemical Shifts ◽  
X Ray ◽  
Structure And Dynamics ◽  
Hydrogen Bonding Interactions ◽  
Overall Stability ◽  
Gold Compounds ◽  
C Nmr

Illusive Au<sup>I/III</sup>···H hydrogen bonds and their effect on structure and dynamics of molecules have been a matter of debate. While a number of X-ray studies reported gold compounds with short Au<sup>I/III</sup>···H contacts, a solid spectroscopic evidence for Au<sup>I/III</sup>···H bonding has been missing. Recently<a></a><a>, Bakar <i>et al.</i></a> (NATURE COMMUNICATIONS 8:576) reported compound with four short Au···H contacts (2.61­–2.66 Å; X-ray determined). Assuming the central cluster be [Au<sub>6</sub>]<sup>2+</sup>and observing the <sup>1</sup>H (<sup>13</sup>C) NMR resonances at relevant H(C) nuclei deshielded with respect to precursor compound, the authors concluded with reservations that <i>“the present Au···H–C interaction is a kind of “hydrogen bond”, where the [Au<sub>6</sub>]<sup>2+</sup>serves as an acceptor”</i>. Here, we show that the Au<sub>6</sub>cluster in their compound bears negative charge and the Au···H contacts lead to a weak (~1 kcal/mol) auride···hydrogen bonding interactions, though unimportant for the overall stability of<b></b>the molecule. Additionally, computational analysis of NMR chemical shifts reveals that the deshielding effects at respective hydrogen nuclei are not directly related to Au···H–C hydrogen bonding .

Correspondence: Hydrogen Bond to Gold? 1H NMR is Not a Proof of Hydrogen Bonds in Transition Metal Complexes

2018 ◽  
Author(s):  
Jan Vícha ◽  
Cina Foroutan-Nejad ◽  
Michal Straka
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Chemical Shifts ◽  
X Ray ◽  
Structure And Dynamics ◽  
Hydrogen Bonding Interactions ◽  
Overall Stability ◽  
Gold Compounds ◽  
C Nmr

Illusive Au<sup>I/III</sup>···H hydrogen bonds and their effect on structure and dynamics of molecules have been a matter of debate. While a number of X-ray studies reported gold compounds with short Au<sup>I/III</sup>···H contacts, a solid spectroscopic evidence for Au<sup>I/III</sup>···H bonding has been missing. Recently<a></a><a>, Bakar <i>et al.</i></a> (NATURE COMMUNICATIONS 8:576) reported compound with four short Au···H contacts (2.61­–2.66 Å; X-ray determined). Assuming the central cluster be [Au<sub>6</sub>]<sup>2+</sup>and observing the <sup>1</sup>H (<sup>13</sup>C) NMR resonances at relevant H(C) nuclei deshielded with respect to precursor compound, the authors concluded with reservations that <i>“the present Au···H–C interaction is a kind of “hydrogen bond”, where the [Au<sub>6</sub>]<sup>2+</sup>serves as an acceptor”</i>. Here, we show that the Au<sub>6</sub>cluster in their compound bears negative charge and the Au···H contacts lead to a weak (~1 kcal/mol) auride···hydrogen bonding interactions, though unimportant for the overall stability of<b></b>the molecule. Additionally, computational analysis of NMR chemical shifts reveals that the deshielding effects at respective hydrogen nuclei are not directly related to Au···H–C hydrogen bonding .

Polysulfonylamine, CXVII Wasserstoffbrücken in kristallinen Onium-dimesylamiden: Sechs systematisch variierte sek.-Ammonium-dimesylamide mit sechs verschiedenen null-, ein-oder zweidimensionalen Wasserstoffbrückenmustern/ Polysulfonylamines, CXVII Hydrogen Bonding in Crystalline Onium Dimesylamides: Six Systematically Varied sec. - Ammonium Dimesylamides Exhibiting Six Different Zero-, One-, or Two-Dimensional Hydrogen Bonding Patterns

1999 ◽  
Vol 54 (11) ◽  
pp. 1420-1430 ◽  
Author(s):  
Oliver Moers ◽  
Karna Wijaya ◽  
Dagmar Henschel ◽  
Armand Blaschette ◽  
Peter G. Jones
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Ionic Crystals ◽  
Molecular Fragments ◽  
Triclinic Space Group ◽  
X Ray ◽  
Rigid Conformation ◽  
Morpholinium Salt ◽  
Crystal Packings

In order to examine packing preferences and hydrogen bond patterns in secondary ammonium salts, low-temperature X-ray analyses were conducted for six compounds of general formula R2NH2+MeSO2)2 N-, where R2NH2+ = Me2NH2+ (1, triclinic, space group P1̄̄), MeEtNH2+,(2, monoclinic, P21/c), Et2NH2+ (3. triclinic, P1), pyrrolidinium (4, triclinic, P1), piperidinium (5, monoclinic, C2/c) or morpholinium (6, monoclinic, P21/c). Throughout the series, the constant anion retains a rigid conformation approximating to C2 symmetry and thus provides a geometrically reliable set of five potential hydrogen bond acceptors. Nevertheless, the six compounds exhibit a variety of unpredictable packing patterns, showing that, in unfavourable cases, the steric demands of molecular fragments not involved in hydrogen bonding can substantially alter the structure of a family of ionic crystals. In the present structures, the NH2+ donor groups form hydrogen bonds N+-H···N-/O to two (3-6) or three (1,2) adjacent anions. The occurrence of various two-, three- and four-centre hydrogen bonds leads to six different patterns, resulting in cation-anion layers (1, 2), discrete formula unit dimers (3, 4) or cation-anion chains (5, 6); in the morpholinium salt 6, these chains are associated into layers by a weak N+ - H ··· O(cation) interaction. In each of the crystal packings, short C-H···O contacts with H···O ≤ 270 pm and C-H ···O ≥ 130° are observed.

scholarly journals The role of nitro groups in the binding of nitroaromatics to protein MOPC 315

1978 ◽  
Vol 173 (3) ◽  
pp. 713-722 ◽  
Author(s):  
P Gettins ◽  
D Givol ◽  
R A Dwek
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
High Resolution ◽  
Hydrogen Bonds ◽  
Fluorescence Quenching ◽  
Nitro Group ◽  
Protein Interactions ◽  
Chemical Shifts ◽  
Binding Constants

Two series of dinitrophenyl haptens, in which chlorine replaces one or both nitro groups, were used to investigate, by a combination of high-resolution 1H n.m.r. and fluorescence quenching, the presence of groups in the combining site of protein MOPC 315, which form hydrogen bonds to the aromatic-ring substituents of the hapten. The large differences in binding constants on successive replacement of nitro groups were shown to be due to specific hapten-substituent-protein interactions by (a) showing that there was little difference in the interaction between these haptens and 3-methylindole (a model for the residue tryptophan-93L with which the hapten stacks in protein MOPC 315), (b) proving by 1H n.m.r. that the mode of hapten binding is constant and (c) showing that the differences in Kd were consistent with the relative hydrogen-bonding capacities of chlorine and the nitro moiety. In this way it was established that each nitro group forms a hydrogen bond. Furthermore, from consideration of the 1H n.m.r. chemical shifts of several dinitrophenyl haptens and their trinitrophenyl analogues, it was shown that there is no distortion of the o-nitro group on binding to the variable fragment of protein MOPC 315.

Unusual hydrogen bonding inL-cysteine hydrogen fluoride

2015 ◽  
Vol 71 (8) ◽  
pp. 733-741
Author(s):  
V. S. Minkov ◽  
V. V. Ghazaryan ◽  
E. V. Boldyreva ◽  
A. M. Petrosyan
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Hydrogen Fluoride ◽  
Fluoride Ion ◽  
X Ray Diffraction ◽  
Monoclinic System ◽  
X Ray ◽  
Short Hydrogen Bond ◽  
Doubly Charged

L-Cysteine hydrogen fluoride, or bis(L-cysteinium) difluoride–L-cysteine–hydrogen fluoride (1/1/1), 2C3H8NO2S+·2F−·C3H7NO2S·HF or L-Cys+(L-Cys...L-Cys+)F−(F−...H—F), provides the first example of a structure with cations of the `triglycine sulfate' type,i.e.A+(A...A+) (whereAandA+are the zwitterionic and cationic states of an amino acid, respectively), without a doubly charged counter-ion. The salt crystallizes in the monoclinic system with the space groupP21. The dimeric (L-Cys...L-Cys+) cation and the dimeric (F−...H—F) anion are formedviastrong O—H...O or F—H...F hydrogen bonds, respectively, with very short O...O [2.4438 (19) Å] and F...F distances [2.2676 (17) Å]. The F...F distance is significantly shorter than in solid hydrogen fluoride. Additionally, there is another very short hydrogen bond, of O—H...F type, formed by a L-cysteinium cation and a fluoride ion. The corresponding O...F distance of 2.3412 (19) Å seems to be the shortest among O—H...F and F—H...O hydrogen bonds known to date. The single-crystal X-ray diffraction study was complemented by IR spectroscopy. Of special interest was the spectral region of vibrations related to the above-mentioned hydrogen bonds.

scholarly journals 2,2′-Bipyridin-1′-ium 1-oxide bromide monohydrate

2018 ◽  
Vol 74 (3) ◽  
pp. 341-344 ◽  
Author(s):  
Katharina Heintz ◽  
Helmar Görls ◽  
Wolfgang Imhof
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Water Molecule ◽  
Title Compound ◽  
Structural Disorder ◽  
Occupancy Rate ◽  
Hydrogen Bonding Interactions ◽  
Bromide Ions

The title compound 2,2′-bipyridin-1′-ium 1-oxide bromide crystallizes as a monohydrate, C10H9N2+·Br−·H2O. Structural disorder is observed due to the fact that protonation, as well as oxidation, of the N atoms of 2,2′-bipyridine occurs at either of the N atoms. The disorder extends to the remainder of the cation, with a refined occupancy rate of 0.717 (4) for the major moiety. An intramolecular N—H...O hydrogen bond forces the bipyridine unit into ans-cisconformation. Each pair of neighbouring 2,2′-bipyridin-1′-ium ions forms a dimeric aggregate by hydrogen bonds between their respective N—O and the N—H functions. These dimers and hydrogen-bonding interactions with bromide ions and the water molecule give rise to a complex supramolecular arrangement.

Structure in “Amorphous Regions”, Accessible Segments of Fibrils, of the Cotton Fiber

1988 ◽  
Vol 58 (2) ◽  
pp. 96-101 ◽  
Author(s):  
Stanley P. Rowland ◽  
Phyllis S. Howley
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Cotton Fiber ◽  
Cotton Fibers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Chemical Studies

The extent of hydrogen bonding of O(3)H and O(6)H in “amorphous” regions, more specifically in accessible segments of fibrils, of the cotton fiber varied from near perfection to almost complete disorder in samples under examination. Perfection of hydrogen bonding in various samples and segments of cotton fibers decreased with decreasing crystallinity of the cellulose within the fibrils. For the most part, extents of O(3)H hydrogen bonding and O(6)H hydrogen bonding followed similar patterns with substantial differences in degrees of perfection, the O(3)H ranging from about 95% hydrogen bonding down to 8% and the O(6)H) from 92% down to 41%. Details of hydrogen bonds assessed in these chemical studies are discussed relative to crystallinities and assignments of hydrogen bond structures from x-ray diffraction studies.

scholarly journals On hydrogen bonding in 1,6-anhydro-β-D-glucopyranose (levoglucosan): X-ray and neutron diffraction and DFT study

2006 ◽  
Vol 62 (5) ◽  
pp. 912-918 ◽  
Author(s):  
Ľubomír Smrčok ◽  
Mariana Sládkovičová ◽  
Vratislav Langer ◽  
Chick C. Wilson ◽  
Miroslav Koóš
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Solid State ◽  
Hydrogen Bonds ◽  
Neutron Diffraction ◽  
Dft Calculations ◽  
Diffraction Data ◽  
Neutron Diffraction Study ◽  
Single Crystal Diffraction ◽  
X Ray

The geometry of hydrogen bonds in 1,6-anhydro-β-D-glucopyranose (levoglucosan) is accurately determined by refinement of time-of-flight neutron single-crystal diffraction data. Molecules of levoglucosan are held together by a hydrogen-bond array formed by a combination of strong O—H...O and supporting weaker C—H...O bonds. These are fully and accurately detailed by the neutron diffraction study. The strong hydrogen bonds link molecules in finite chains, with hydroxyl O atoms acting as both donors and acceptors of hydroxyl H atoms. A comparison of molecular and solid-state DFT calculations predicts red shifts of O—H and associated blue shifts of C—H stretching frequencies due to the formation of hydrogen bonds in this system.

Polysulfonylamine, CLIII [1]. Schwache Wasserstoffbrücken mit aktivierten Methyldonoren: Kristallstrukturen von Cholinium-, Betainium- und Dimethyl[2-(dimethylamino)ethyl]ammonium-dimesylamid Polysulfonylamines, CLIII [1]. Weak Hydrogen Bonding with Activated Methyl Donors: Crystal Structures of Cholinium, Betainium and Dimethyl[2-(dimethylamino)ethyl]ammonium-dimesylamide

2002 ◽  
Vol 57 (5) ◽  
pp. 534-546 ◽  
Author(s):  
Dagmar Henschel ◽  
Oliver Moers ◽  
Karna Wijaya ◽  
Andreas Wirth ◽  
Armand Blaschette ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Orthorhombic Space Group ◽  
Methyl Donors ◽  
X Ray ◽  
Onium Salts ◽  
Weak Hydrogen Bonds ◽  
Weak Hydrogen Bonding ◽  
Normalized Parameters

In order to study weak hydrogen bonds originating from inductively activated C(sp3)-H donor groups, low-temperature X-ray structures are reported for three onium salts of general formula BH+(MeSO2)2N-, where BH+ is Me3N+CH2CH2OH (1; orthorhombic, space group P212121, Z′ = 1), Me3N+CH2C(O)OH (2; orthorhombic, P212121, Z′ = 1), or Me2HN+CH2CH2NMe2 (3; monoclinic, P21/c, Z′ = 1). The asymmetric units consist of cationanion pairs assembled by an O-H···O=S hydrogen bond in 1, an O-H···N- bond in 2, and an N+-H ··· N- bond in 3. The packings display a plethora of short interionic C(sp3)-H···O/N contacts that are geometrically consistent with weak hydrogen bonding; those taken into consideration have normalized parameters d(H ··· O) ≤ 269 pm, d(H···N) ≤ 257 pm and θ(C-H···O/N) ≥ 127°. The roles of the weak hydrogen bonds are as follows: In structures 1 and 3, the anions are associated into corrugated layers, which intercalate catemers of cations (1) or stacks of discrete cations (3), whereas structure 2 involves cation catemers surrounded by four anion catemers and vice versa; moreover, all cations are linked to adjacent anions by several weak hydrogen bonds (and to one anion in particular by the strong H bond). Among the cation-anion interactions, the N+(CH2-H···)3O tripod pattern arising in 1 and 2 is of special interest.

Diethyl 2-Benzimidazol-1-ylsuccinate–Picric Acid (1/1) – An Inclusion Molecular Complex

1997 ◽  
Vol 53 (6) ◽  
pp. 961-967 ◽  
Author(s):  
P. Zaderenko ◽  
M. S. Gil ◽  
P. López ◽  
P. Ballesteros ◽  
I. Fonseca ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Molecular Complex ◽  
Picric Acid ◽  
X Ray Diffraction ◽  
Nmr Studies ◽  
X Ray ◽  
H Nmr ◽  
Intramolecular Hydrogen ◽  
C Nmr

The crystal structure of the diethyl 2-benzimidazol-1-ylsuccinate–picric acid (1/1) molecular complex has been determined by X-ray diffraction analysis. Diethyl 2-benzimidazol-l-ylsuccinate molecules form channels along the a axis, in which the picric acid molecules are located. The benzimidazole moiety and the phenol group are held together by hydrogen bonding between the hydrogen of the phenol and the N3 atom of benzimidazole. Additionally, this hydrogen forms an intramolecular hydrogen bond with one O atom of the ortho-nitro group, thus producing a bifurcated hydrogen bond. 1H NMR spectra in DMSO-d 6 solution and CP/MAS solid 13 C NMR studies of this 2-benzimidazol-1-ylsuccinate–picric acid (1/1) molecular complex, as well as those of dimethyl, diethyl, di-n-butyl and 1-n-butyl-4-ethyl 2-imidazol-1-ylsuccinates, diethyl 2-pyrazol-1-ylsuccinate, ethyl imidazol-1-ylacetate, ethyl pyrazol-1-ylacetate and ethyl pyrazol-l-ylsuccinate, suggest that the picric acid linkage depends on the nature of the azole. Actual proton transfer is deduced for the imidazole derivatives, but only weak hydrogen bonding could be inferred for pyrazole derivatives.

scholarly journals Crystal structure of bis(4-benzoylpyridine-κN)bis(methanol-κO)bis(thiocyanato-κN)nickel(II) methanol monosolvate

2019 ◽  
Vol 75 (2) ◽  
pp. 299-303 ◽  
Author(s):  
Carsten Wellm ◽  
Christian Näther
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Powder Diffraction ◽  
Three Dimensional ◽  
Asymmetric Unit ◽  
X Ray ◽  
Hydrogen Bonding Interactions ◽  
Dimensional Network ◽  
Pure Phase

The asymmetric unit of the title compound, [Ni(NCS)2(C12H9NO)2(CH3OH)2]·CH3OH, comprises one NiII cation, two thiocyanate anions, two 4-benzoylpyridine coligands, two coordinating, as well as one non-coordinating methanol molecule. The NiII cation is coordinated by two terminally N-bonded thiocyanate anions, the N atoms of two 4-benzoylpyridine coligands and the O atoms of two methanol ligands within a slightly distorted octahedron. Individual complexes are linked by intermolecular O—H...S hydrogen bonding into chains parallel to [010] that are further connected into layers parallel to (10\overline{1}) by C—H...S hydrogen bonds. Additional C—H...O hydrogen-bonding interactions lead to the formation of a three-dimensional network that limits channels extending parallel to [010] in which the non-coordinating methanol molecules are located. They are hydrogen-bonded to the coordinating methanol molecules. X-ray powder diffraction revealed that the compound could not be prepared as a pure phase.

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