N-Heterocyclic Carbenes: Exotic Molecules as Precursors to Unusual Hydrogen Bonds

ChemInform ◽  
2004 ◽  
Vol 35 (45) ◽  
Author(s):  
Jonathan K. W. Chui ◽  
Taramatee Ramnial ◽  
Jason A. C. Clyburne
Keyword(s):  
Hydrogen Bonds ◽  
Heterocyclic Carbenes ◽  
Exotic Molecules

N-HETEROCYCLIC CARBENES: EXOTIC MOLECULES AS PRECURSORS TO UNUSUAL HYDROGEN BONDS

2003 ◽  
Vol 24 (5-6) ◽  
pp. 165-187 ◽  
Author(s):  
JONATHAN K. W. CHUI ◽  
TARAMATEE RAMNIAL ◽  
JASON A. C. CLYBURNE
Keyword(s):  
Hydrogen Bonds ◽  
Heterocyclic Carbenes ◽  
Exotic Molecules

Two Fe3(μ3-S)2(CO)8clusters with terminal N-heterocyclic carbenes

2014 ◽  
Vol 70 (6) ◽  
pp. 528-532 ◽  
Author(s):  
Wei Yang ◽  
Qiang Fu ◽  
Jing Zhao ◽  
Huan-Ren Cheng ◽  
Yao-Cheng Shi
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Heterocyclic Carbenes ◽  
Carbonyl Ligands

The title compounds with terminal N-heterocyclic carbenes, namely octacarbonyl(imidazolidinylidene-κC2)di-μ3-sulfido-triiron(II)(2Fe—Fe), [Fe3(C3H6N2)(μ3-S)2(CO)8], (I), and octacarbonyl(1-methylimidazo[1,5-a]pyridin-3-ylidene-κC3)di-μ3-sulfido-triiron(II)(2Fe—Fe), [Fe3(C8H8N2)(μ3-S)2(CO)8], (II), have been synthesized. Each compound contains two Fe—Fe bonds and two S atoms above and below a triiron triangle. One of the eight carbonyl ligands deviates significantly from linearity. In (I), dimers generated by an N—H...S hydrogen bond are linked into [001] double chains by a second N—H...S hydrogen bond. These chains are packed by a C—H...O hydrogen bond to yield [101] sheets. In (II), dimers generated by an N—H...S hydrogen bond are linked by C—H...O hydrogen bonds to form [111] double chains.

scholarly journals Dissolving Cellulose in 1,2,3-Triazolium- and Imidazolium-Based Ionic Liquids with Aromatic Anions

Molecules ◽  
2020 ◽  
Vol 25 (15) ◽  
pp. 3539 ◽  
Author(s):  
Martin Brehm ◽  
Julian Radicke ◽  
Martin Pulst ◽  
Farzaneh Shaabani ◽  
Daniel Sebastiani ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Ionic Liquids ◽  
Hydrogen Bonds ◽  
Md Simulations ◽  
Heterocyclic Carbenes ◽  
Quantitative Prediction ◽  
Lower Amount ◽  
New Class ◽  
Aromatic Anions ◽  
Lower Basicity

We present 1,2,3-triazolium- and imidazolium-based ionic liquids (ILs) with aromatic anions as a new class of cellulose solvents. The two anions in our study, benzoate and salicylate, possess a lower basicity when compared to acetate and therefore should lead to a lower amount of N-heterocyclic carbenes (NHCs) in the ILs. We characterize their physicochemical properties and find that all of them are liquids at room temperature. By applying force field molecular dynamics (MD) simulations, we investigate the structure and dynamics of the liquids and find strong and long-lived hydrogen bonds, as well as significant π–π stacking between the aromatic anion and cation. Our ILs dissolve up to 8.5 wt.-% cellulose. Via NMR spectroscopy of the solution, we rule out chain degradation or derivatization, even after several weeks at elevated temperature. Based on our MD simulations, we estimate the enthalpy of solvation and derive a simple model for semi-quantitative prediction of cellulose solubility in ILs. With the help of Sankey diagrams, we illustrate the hydrogen bond network topology of the solutions, which is characterized by competing hydrogen bond donors and acceptors. The hydrogen bonds between cellulose and the anions possess average lifetimes in the nanosecond range, which is longer than found in common pure ILs.

scholarly journals Preferential N–H⋯:C hydrogen bonding involving ditopic NH-containing systems and N-heterocyclic carbenes

RSC Advances ◽  
2020 ◽  
Vol 10 (69) ◽  
pp. 42164-42171
Author(s):  
Zacharias J. Kinney ◽  
Arnold L. Rheingold ◽  
John D. Protasiewicz
Keyword(s):  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Heterocyclic Carbenes ◽  
Secondary Amines ◽  
Solution State

Non-traditional hydrogen bonds between a singlet carbene and a series of ditopic secondary amines is detailed. Both the solid- and solution-state metrics reveal the strength of these associations are dependent on the pKa of the NH-containing molecule.

Unveiling the peculiar hydrogen bonding behavior of solvated N-heterocyclic carbenes

2016 ◽  
Vol 18 (1) ◽  
pp. 126-140 ◽  
Author(s):  
Oldamur Hollóczki
Keyword(s):  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Force Field ◽  
Practical Importance ◽  
Md Simulations ◽  
Heterocyclic Carbenes ◽  
Mechanical Force

After fitting a molecular mechanical force field for imidazol-2-ylidenes, MD simulations revealed carbene–carbene and three-center hydrogen bonds of carbenes. The practical importance of these structures is also highlighted.

Use of molecular overlap to predict intermolecular repulsion in N... H-O hydrogen bonds

1998 ◽  
Vol 95 (3) ◽  
pp. 525-537 ◽  
Author(s):  
I. NOBELI S. L. PRICE R. J. WHEATLEY
Keyword(s):  
Hydrogen Bonds

On symmetrical O-H-O hydrogen bonds

1964 ◽  
Vol 25 (5) ◽  
pp. 487-492 ◽  
Author(s):  
R.E. Rundle
Keyword(s):  
Hydrogen Bonds

A Crystallographic Study of Bis[S-benzyl-5-bromo-2-oxoindolin-3-ylidenemethanehydrazonthioate] Disulfide Solvated with Dimethylsulfoxide

2012 ◽  
Vol 9 (2) ◽  
pp. 87
Author(s):  
Mohd Abdul Fatah Abdul Manan ◽  
M. Ibrahim M. Tahir ◽  
Karen A. Crouse ◽  
Fiona N.-F. How ◽  
David J. Watkin
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Solvent Molecule ◽  
Site Occupancy ◽  
Unit Cell Parameters ◽  
Intermolecular Hydrogen Bonds ◽  
Triclinic Space Group ◽  
Cell Parameters ◽  
Crystallographic Study ◽  
Thiol Form

The crystal structure of the title compound has been determined. The compound crystallized in the triclinic space group P -1, Z = 2, V = 1839 .42( 18) A3 and unit cell parameters a= 11. 0460( 6) A, b = 13 .3180(7) A, c=13. 7321 (8) A, a = 80.659(3 )0, b = 69 .800(3 )0 and g = 77 .007 (2)0 with one disordered dimethylsulfoxide solvent molecule with the sulfur and oxygen atoms are distributed over two sites; S101/S102 [site occupancy factors: 0.6035/0.3965] and 0130/0131 [site occupancy factor 0.3965/0.6035]. The C22-S2 l and C 19-S20 bond distances of 1. 779(7) A and 1. 788(8) A indicate that both of the molecules are connected by the disulfide bond [S20-S21 2.055(2) A] in its thiol form. The crystal structure reveals that both of the 5-bromoisatin moieties are trans with respect to the [S21-S20 and CI 9-Nl 8] and [S20-S21 and C22-N23] bonds whereas the benzyl group from the dithiocarbazate are in the cis configuration with respect to [S21-S20 and C19-S44] and [S20-S21 and C22-S36] bonds. The crystal structure is further stabilized by intermolecular hydrogen bonds of N9-H35···O16 formed between the two molecules and N28-H281 ···O130, N28-H281 ···O131 and C4 l-H4 l l ···O 131 with the solvent molecule.

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