scholarly journals Main Chain Noncentrosymmetric Hydrogen Bonded Macromolecules Incorporating Aniline, Alkanol, and Alkanoic Acid Hydrogen Bond Donors

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Jeremy R. Wolf
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Main Chain ◽  
Attenuated Total Reflectance ◽  
Intermolecular Hydrogen Bonding ◽  
Hydrogen Bond Donor ◽  
Alkanoic Acid ◽  
Total Reflectance ◽  
Hydrogen Bonded

The syntheses and characterization of three noncentrosymmetric main chain hydrogen bonded macromolecules which incorporate aniline, alkanoic acid, and alkanol hydrogen bond donor units are reported. These macromolecules participate in weak intermolecular hydrogen bonding as demonstrated using attenuated total reflectance (ATR) FTIR. The phase transitions of these macromolecules depend on the identity of the hydrogen bond donor.

Rage Against Conformity: Ruthenium(ɪɪ) Bisterpyridine Complexes Respond to Crystal Engineering Instructions with Whelming Results

2017 ◽  
Vol 70 (5) ◽  
pp. 529 ◽  
Author(s):  
Hasti Iranmanesh ◽  
Kasun S. A. Arachchige ◽  
William A. Donald ◽  
Niamh Kyriacou ◽  
Chao Shen ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Solid State ◽  
Single Crystal ◽  
Crystal Engineering ◽  
Intermolecular Hydrogen Bonding ◽  
Hydrogen Bond Donor ◽  
One Dimensional ◽  
X Ray ◽  
Hydrogen Bonded

Four heteroleptic ruthenium(ii) complexes of 4′-functionalised 2,2′:6′,2′′-terpyridine are reported, along with their solid-state single-crystal X-ray structures. The complexes feature complementary hydrogen-bond donor (phenol) and acceptor (pyridyl) groups designed to assemble into one-dimensional polymers. In one example, the system obeys the programmed instructions to form a one-dimensional, self-complementary hydrogen-bonded polymer. In one other example, a water-bridged hydrogen-bonded polymer is formed. In the remaining two structures, aryl–aryl interactions dominate the intermolecular interactions, and outweigh the contribution of intermolecular hydrogen bonding.

New supramolecular architectures using hydrogen bonding

1993 ◽  
Vol 345 (1674) ◽  
pp. 49-56 ◽  
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Hydrogen Bond Donor ◽  
Binding Strength ◽  
Supramolecular Architectures ◽  
Self Assembling ◽  
Donor And Acceptor ◽  
The Stability ◽  
Bonded Complexes ◽  
Hydrogen Bonded

Several new multiply hydrogen bonded complexes have been studied to determine their strength and the specificity with which they form. While many factors contribute to the stability of multiply hydrogen bonded complexes, it appears that the arrangement of the hydrogen bond donor and acceptor groups is a particularly good predictor of binding strength. The results are consistent with W. L. Jorgensen’s secondary electrostatic hypothesis. The heterocyclic recognition units that have been synthesized may serve as the basis for constructing new synthetic hosts or new self-assembling systems.

scholarly journals Protonation sites and hydrogen bonding in mono-hydrobromide salts of two N,4-diheteroaryl 2-aminothiazoles

2021 ◽  
Author(s):  
Denise Böck ◽  
Andreas Beuchel ◽  
Richard Goddard ◽  
Adrian Richter ◽  
Peter Imming ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Three Dimensional ◽  
Water Molecules ◽  
Monoclinic Space Group ◽  
Intermolecular Hydrogen Bonding ◽  
Molecular Conformations ◽  
Space Group ◽  
Hydrogen Bonded

AbstractThe synthesis and structural characterization of N-(6-methoxypyridin-3-yl)-4-(pyridin-2-yl)thiazol-2-amine mono-hydrobromide monohydrate (3) and N-(6-methoxypyridin-3-yl)-4-(pyrazin-2-yl)thiazol-2-amine mono-hydrobromide 0.35 methanol solvate (4) are reported. The crystal structures of 3 (monoclinic, space group P21/n, Z = 4) and 4 (monoclinic, space group, C2/c, Z = 8) feature N,4-diheteroaryl 2-aminothiazoles showing similar molecular conformations but different sites of protonation and thus distinctly different intermolecular hydrogen bonding patterns. In 3, Namine–H⋯Br−, N+pyridine–H⋯Owater, and Owater–H⋯Br− hydrogen bonds link protonated N-(6-methoxypyridin-3-yl)-4-(pyridin-2-yl)thiazol-2-amine and water molecules and bromide anions into a three-dimensional hydrogen-bonded network, whereas intermolecular N+methoxypyridine–H⋯Npyrazine hydrogen bonds result in hydrogen-bonded zigzag chains of protonated N-(6-methoxypyridin-3-yl)-4-(pyrazin-2-yl)thiazol-2-amine molecules in 4.

scholarly journals Electrospun Membranes Based on Polycaprolactone, Nano-Hydroxyapatite and Metronidazole

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 931
Author(s):  
Ioana-Codruţa Mirică ◽  
Gabriel Furtos ◽  
Ondine Lucaciu ◽  
Petru Pascuta ◽  
Mihaela Vlassa ◽  
...  
Keyword(s):  
Fiber Diameter ◽  
Maximum Load ◽  
Guided Bone Regeneration ◽  
Attenuated Total Reflectance ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Total Reflectance ◽  
X Ray ◽  
Electrospun Membranes

The aim of this research was to develop new electrospun membranes (EMs) based on polycaprolactone (PCL) with or without metronidazole (MET)/nano-hydroxyapatite (nHAP) content. New nHAP with a mean diameter of 34 nm in length was synthesized. X-ray diffraction (XRD) and attenuated total reflectance Fourier transform infrared spectroscopy (FTIR-ATR) were used for structural characterization of precursors and EMs. The highest mechanical properties (the force at maximum load, Young’s modulus and tensile strength) were found for the PCL membranes, and these properties decreased for the other samples in the following order: 95% PCL + 5% nHAP > 80% PCL + 20% MET > 75% PCL + 5% nHAP + 20% MET. The stiffness increased with the addition of 5 wt.% nHAP. The SEM images of EMs showed randomly oriented bead-free fibers that generated a porous structure with interconnected macropores. The fiber diameter showed values between 2 and 16 µm. The fiber diameter increased with the addition of nHAP filler and decreased when MET was added. New EMs with nHAP and MET could be promising materials for guided bone regeneration or tissue engineering.

Investigation of Hydrogen Bonding Interaction between Bolaform Schiff Bases with Barbituric Acid by HPLC

2011 ◽  
Vol 356-360 ◽  
pp. 48-51
Author(s):  
Qi Tong ◽  
Ti Feng Jiao
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Liquid Chromatography ◽  
Schiff Bases ◽  
Barbituric Acid ◽  
Flexible Structure ◽  
Intermolecular Hydrogen Bonding ◽  
Acid Molecule ◽  
Hydrogen Bonding Interaction ◽  
Bonding Interaction

In order to investigate the intermolecular hydrogen bonding of special amphiphiles, two bolaform amphiphilic Schiff bases (GN1 and GN2) with different hydrophilic spacers were designed, and their interaction with barbituric acid were tested by liquid chromatography. The chromatographic properties showed that both the Schiff bases showed hydrogen bonding interaction with barbituric acid. In addition, the influence of various detectors was also studied on both cases. Experimental results show that the test with FLD showed better determination than other detectors. It is proposed that due to the directionality and strong matching of hydrogen bond, one barbituric acid molecule can be encapsulated into the intramolecular area of GN1, while two barbituric acid molecules were trapped into the GN2 molecule through intermolecular H-bonds for GN2 due to the long spacer and flexible structure. A rational complex mode was proposed.

scholarly journals Machine learning models for hydrogen bond donor and acceptor strengths using large and diverse training data generated by first-principles interaction free energies

2019 ◽  
Vol 11 (1) ◽  
Author(s):  
Christoph A. Bauer ◽  
Gisbert Schneider ◽  
Andreas H. Göller
Keyword(s):  
Machine Learning ◽  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Training Data ◽  
Free Energies ◽  
Hydrogen Bond Donor ◽  
Chemical Application ◽  
Hydrogen Bond Acceptor ◽  
Donor And Acceptor ◽  
Target Values

Abstract We present machine learning (ML) models for hydrogen bond acceptor (HBA) and hydrogen bond donor (HBD) strengths. Quantum chemical (QC) free energies in solution for 1:1 hydrogen-bonded complex formation to the reference molecules 4-fluorophenol and acetone serve as our target values. Our acceptor and donor databases are the largest on record with 4426 and 1036 data points, respectively. After scanning over radial atomic descriptors and ML methods, our final trained HBA and HBD ML models achieve RMSEs of 3.8 kJ mol−1 (acceptors), and 2.3 kJ mol−1 (donors) on experimental test sets, respectively. This performance is comparable with previous models that are trained on experimental hydrogen bonding free energies, indicating that molecular QC data can serve as substitute for experiment. The potential ramifications thereof could lead to a full replacement of wetlab chemistry for HBA/HBD strength determination by QC. As a possible chemical application of our ML models, we highlight our predicted HBA and HBD strengths as possible descriptors in two case studies on trends in intramolecular hydrogen bonding.

ATR-Spin: An open-source 3D printed device for direct cytocentrifugation onto Attenuated Total Reflectance crystals.

Lab on a Chip ◽  
2021 ◽  
Author(s):  
David Perez-Guaita ◽  
Zack Richardson ◽  
G. Quintas ◽  
Julia Kuligowski ◽  
Diana Eva Bedolla ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Molecular Level ◽  
Point Of Care ◽  
Attenuated Total Reflectance ◽  
Cell Preparation ◽  
Total Reflectance ◽  
Point Of Care Diagnostics ◽  
3D Printed ◽  
Rapid Characterization

Infrared Spectroscopy (IR) enables the direct and rapid characterization of cells at the molecular level. Achieving a rapid and consistent cell preparation is critical for the development of Point-of-Care diagnostics...

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