Theoretical and Experimental Study of Monofunctional Vinyl Cyclopropanes Bearing Hydrogen Bond Enabling Side Chains

2021 ◽  
Author(s):  
Sören Schumacher ◽  
Sanwardhini Pantawane ◽  
Stephan Gekle ◽  
Seema Agarwal
Keyword(s):  
Experimental Study ◽  
Hydrogen Bond ◽  
Side Chains

Influence of the geometry of a hydrogen bond on conformational stability: a theoretical and experimental study of ethyl carbamate

2009 ◽  
Vol 11 (11) ◽  
pp. 1719 ◽  
Author(s):  
M. Goubet ◽  
R. A. Motiyenko ◽  
F. Réal ◽  
L. Margulès ◽  
T. R. Huet ◽  
...  
Keyword(s):  
Experimental Study ◽  
Hydrogen Bond ◽  
Conformational Stability ◽  
Ethyl Carbamate

scholarly journals 4-{[Bis(2-hydroxyethyl)amino]methyl}-6-methoxy-2H-chromen-2-one

2012 ◽  
Vol 68 (8) ◽  
pp. o2413-o2414
Author(s):  
Reshma Naik ◽  
Ravish Sankolli ◽  
G. N. Anil Kumar ◽  
T. N. Guru Row ◽  
Manohar V. Kulkarni
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Membered Ring ◽  
Side Chains ◽  
Stacking Interactions ◽  
Compound C ◽  
Π Stacking ◽  
Centroid Distance

In the title compound, C15H19NO5, an intramolecular O—H...O hydrogen bond links the hydroxyethyl side chains, forming a seven-membered ring. In the crystal, molecules are linked into chainsviaO—H...O hydrogen bonds along thebaxis. Further, molecules are linked by weak intermolecular C—H...O and π–π stacking interactions [centroid–centroid distance = 3.707 (4) Å].

scholarly journals Implication of Ile-69 and Thr-182 residues in kinetic characteristics of IRT-3 (TEM-32) beta-lactamase.

1996 ◽  
Vol 40 (10) ◽  
pp. 2434-2436 ◽  
Author(s):  
S Farzaneh ◽  
E B Chaibi ◽  
J Peduzzi ◽  
M Barthelemy ◽  
R Labia ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Catalytic Activity ◽  
Water Molecule ◽  
Side Chains ◽  
Beta Lactamase ◽  
Kinetic Characteristics ◽  
Beta Lactamases ◽  
Inhibitor Resistance

The substitution of a methionine for an isoleucine at position 69 (Met69Ile), which causes inhibitor resistance to TEM-type beta-lactamases (IRT-3 and IRT-I69), altered the positions of the Asn-170 and Glu-166 side chains as well as the position of the catalytic water molecule. A novel hydrogen bond between the hydroxyl of Thr-182 and the carbonyl of Glu-64 was expected to be responsible for the increase in the catalytic activity of the IST-T182 and IRT-3 enzymes compared with those of TEM-1 and IRT-169, respectively.

Hydration and Proton Transfer in 3M™ PEM Ionomers: An Ab Initio Study

2012 ◽  
Vol 1384 ◽  
Author(s):  
Jeffrey K. Clark ◽  
Stephen J. Paddison
Keyword(s):  
Hydrogen Bond ◽  
Proton Transfer ◽  
The State ◽  
Side Chain ◽  
Water Molecules ◽  
Side Chains ◽  
Hydrogen Bond Network ◽  
Group Separation ◽  
Proton Dissociation ◽  
Bond Network

ABSTRACTElectronic structure calculations were performed to study the effects local hydration, neighboring side chain connectivity, and protogenic group separation have in facilitating proton dissociation and transfer in fragments of 3M ionomers under conditions of low hydration. Two different types of ionomers, each consisting of a poly(tetrafluoroethylene) (PTFE) backbone, were considered: (1) perfluorosulfonic acid (PFSA) ionomeric fragments containing two pendant side chains (–O(CF2)4SO3H) of distinct separation along the PTFE backbone to model different equivalent weight ionomers and (2) single side chain fragments of three bis(sulfonyl imide)- based fragments with multiple and distinct acid groups per side chain having structural and chemical differences mediating protogenic group separation (side chains: –O(CF2)4SO2(NH)- SO2C6H4SO3H) with the sulfonic acid group located in either the meta or the ortho position on the phenyl ring and –O(CF2)4SO2(NH)SO2(CF2)3SO3H). Fully optimized structures of these fragments with and without the addition of water molecules at the B3LYP/6-311G** level revealed that both side chain connectivity and protogenic group separation, along with local hydration, are key contributors to proton dissociation and the energetics of proton transfer in these materials. Specifically, cooperative interaction between protogenic groups through hydrogen bonding and electron withdrawing –CF2– groups are critical for first proton dissociation and the state of the dissociated proton at low levels of hydration. However, the close proximity of protogenic groups in the ortho bis acid precluded second proton dissociation at low hydration as the relatively fixed protogenic group separation promoted interactions between water molecules, while the labile side chains in the PFSA ionomers allowed for greater freedom in the hydrogen bond network formed. Potential energy profiles for proton transfer were determined at the B3LYP/6-31G** level. The energetic penalty associated with proton transfer was found to be strongly dependent on the surrounding hydrogen bond network and the state of the dissociated proton(s), as well as, the separation between protogenic groups.

β Turns, water cage formation and hydrogen bonding in the structures of L-valyl-L-phenylalanine

2002 ◽  
Vol 58 (3) ◽  
pp. 512-518 ◽  
Author(s):  
Carl Henrik Görbitz
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Crystal Packing ◽  
Protein Structures ◽  
Thin Plates ◽  
Water Molecules ◽  
Side Chains ◽  
Type I ◽  
Type Ii ◽  
Model Pair

L-Valyl-L-phenylalanine has been crystallized as an orthorhombic dihydrate (1) in the shape of needles and as a monoclinic trihydrate (2) with Z = 16 (P21, Z′ = 8) in the shape of thin plates. Peptide molecules in these two structures occur in three basic conformations, termed c 1, c 2A and c 2B. c 2B has not been observed previously for dipeptides. Together with c 1 it forms a model pair for Type I and Type II β-turns in protein structures. The crystal packing of (2) is remarkable in that some of the L-Val side chains are exposed to the solvent region of the crystal rather than being located in a hydrophobic layer. The crystal packing thus offers a unique and detailed view of hydrogen-bond cage formation around the hydrophobic groups by the 24 cocrystallized water molecules. The eight —NH_3^+...−OOC— contacts in the structure are unusually short and the minimum N...O distance of 2.649 (5) Å represents a new extreme limit for this type of hydrogen bond in peptide structures.

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