Contrasting anion recognition behaviour exhibited by halogen and hydrogen bonding rotaxane hosts

2015 ◽  
Vol 13 (9) ◽  
pp. 2582-2587 ◽  
Author(s):  
Stuart P. Cornes ◽  
Charles H. Davies ◽  
David Blyghton ◽  
Mark R. Sambrook ◽  
Paul D. Beer
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Halogen Bond ◽  
Anion Recognition ◽  
Dihydrogen Phosphate ◽  
Donor Group ◽  
Hydrogen Bond Donor

A [2]rotaxane anion host that switches selectivity from dihydrogen phosphate to the halides upon substituting a hydrogen bond donor group for a halogen bond donor group within the axle component is described.

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.

scholarly journals Crystal structures of three 3,4,5-trimethoxybenzamide-based derivatives

2016 ◽  
Vol 72 (5) ◽  
pp. 675-682 ◽  
Author(s):  
Ligia R. Gomes ◽  
John Nicolson Low ◽  
Catarina Oliveira ◽  
Fernando Cagide ◽  
Fernanda Borges
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Crystal Structures ◽  
Methoxy Group ◽  
Combined Effect ◽  
Donor Group ◽  
Methoxy Substituent ◽  
A Chain ◽  
Benzamide Derivatives

The crystal structures of three benzamide derivatives,viz. N-(6-hydroxyhexyl)-3,4,5-trimethoxybenzamide, C16H25NO5, (1),N-(6-anilinohexyl)-3,4,5-trimethoxybenzamide, C22H30N2O4, (2), andN-(6,6-diethoxyhexyl)-3,4,5-trimethoxybenzamide, C20H33NO6, (3), are described. These compounds differ only in the substituent at the end of the hexyl chain and the nature of these substituents determines the differences in hydrogen bonding between the molecules. In each molecule, them-methoxy substituents are virtually coplanar with the benzyl ring, while thep-methoxy substituent is almost perpendicular. The carbonyl O atom of the amide rotamer istransrelated with the amidic H atom. In each structure, the benzamide N—H donor group and O acceptor atoms link the molecules intoC(4) chains. In1, a terminal –OH group links the molecules into aC(3) chain and the combined effect of theC(4) andC(3) chains is a ribbon made up of screw relatedR22(17) rings in which the ...O—H... chain lies in the centre of the ribbon and the trimethoxybenzyl groups forms the edges. In2, the combination of the benzamideC(4) chain and the hydrogen bond formed by the terminal N—H group to an O atom of the 4-methoxy group link the molecules into a chain ofR22(17) rings. In3, the molecules are linked only byC(4) chains.

Selective encapsulation and extraction of hydrogenphosphate by a hydrogen bond donor tripodal receptor

CrystEngComm ◽  
2020 ◽  
Vol 22 (37) ◽  
pp. 6152-6160
Author(s):  
Sandeep Kumar Dey ◽  
Archana ◽  
Sybil Pereira ◽  
Sarvesh S. Harmalkar ◽  
Shashank N. Mhaldar ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Hydrogen Bond Donor ◽  
Tripodal Receptor ◽  
Multiple Hydrogen Bonds

Intramolecular N–H⋯OC hydrogen bonding between the inner amide groups dictates the receptor–anion complementarity in a tripodal receptor towards selective encapsulation of hydrogenphosphate in the outer urea cavity by multiple hydrogen bonds.

Polysulfonylamine, CXXVI [1] Wasserstoffbrücken in kristallinen Onium-dimesylamiden: Ein robustes Achtring-Synthon in Koexistenz mit einem dritten Wasserstoffbrückenmotiv - Cyclodimere, Ketten, supramolekulare Bindungsisomere und ein fünffach verwobenes dreidimensionales (C-H ∙∙∙ O - Netzwerk / Polysulfonylamines, CXXVI [1] Hydrogen Bonding in Crystalline Onium Dimesylamides: A Robust Eight- Membered Ring Synthon in Coexistence with a Third Hydrogen Bonding Motif - Cyclodimers, Chains, Supramolecular Linkage Isomers, and a Quintuply Interwoven Three-Dimensional C - H ∙∙∙ O Network

2000 ◽  
Vol 55 (8) ◽  
pp. 738-752 ◽  
Author(s):  
Oliver Moers ◽  
Karna Wijaya ◽  
Ilona Lange ◽  
Armand Blaschette ◽  
Peter G. Jones
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Crystal Engineering ◽  
Ion Pairs ◽  
Three Dimensional ◽  
Membered Ring ◽  
Monoclinic Space Group ◽  
Hydrogen Bond Donor ◽  
Linkage Isomers ◽  
Ionic Solids

As an exercise in crystal engineering, low-temperature X-ray structures were determined for six rationally designed ionic solids of general formula BH+(MeSO2)2N−, where BH+ is 2-aminopyridinium (2, monoclinic, space group P21/c, Z = 4), 2-aminopyrimidinium (3, orthorhombic, Pbca, Z = 8), 2-aminothiazolium (4, orthorhombic, Pbcn, Z = 8), 2-amino-6-methylpyridinium (5, solvated with 0.5 H20, monoclinic, C2/c, Z = 8), 2-amino-1,3,4-thiadiazolium (6, triclinic, P1̄, Z = 2), or 2-amino-4,6-dimethylpyrimidinium (7, orthorhombic. Fdd2, Z = 16). The onium cations in question exhibit a trifunctional hydrogen-bond donor sequence H − N (H*)-C (sp2) − N − H , which is complementary to an O − S (sp3)−N fragment of the anion and simultaneously expected to form a third hydrogen bond via the exocyclic N − H* donor. Consequently, all the crystal packings contain cation-anion pairs assembled by an N − H ∙∙∙ N and an N −H ∙∙∙ O hydrogen bond, these substructures being mutually associated through an N − H* ∙∙∙ O bond. For the robust eight-membered ring synthon within the ion pairs [graph set N2 = R22(8), antidromic], two supramolecular isomers were observed: In 2 and 3, N − H ∙∙∙ N originates from the ring NH donor and N − H ∙∙∙ O from the exocyclic amino group, whereas in 4-7 these connectivities are reversed. The third hydrogen bond, N − H*∙∙∙ O , leads either to chains of ion pairs (generated by a 21 transformation in 2-4 or by a glide plane in 5) or to cyclic dimers of ion pairs (Ci symmetric in 6, C2-symmetric in 7). The overall variety of motifs observed in a small number of structures reflects the limits imposed on the prediction of hydrogen bonding patterns. Owing to the excess of potential acceptors over traditional hydrogen-bond donors, several of the structures display prominent non-classical secondary bonding. Thus, the cyclodimeric units of 6 are associated into strands through short antiparallel O ∙∙∙ S(cation) interactions. In the hemihydrate 5, two independent C-H(cation) ∙∙∙ O bonds generate a second antidromic R22(8) pattern, leading to sheets composed of N − H ∙∙∙ N/O connected catemers; the water molecules are alternately sandwiched between and O - H ∙∙∙ O bonded to the sheets to form bilayers, which are cross-linked by a third C − H (cation ) ∙∙∙ O contact. The roof-shaped cyclodimers occurring in 7 occupy the polar C2 axes parallel to z and build up hollow Car− H ∙∙∙ O bonded tetrahedral lattices; in order to fill their large empty cavities, five translationally equivalent lattices mutually interpenetrate.

scholarly journals CF2H as a hydrogen bond donor group for the fine tuning of peptide bond geometry with difluoromethylated pseudoprolines

2019 ◽  
Vol 55 (83) ◽  
pp. 12487-12490 ◽  
Author(s):  
N. Malquin ◽  
K. Rahgoshay ◽  
N. Lensen ◽  
G. Chaume ◽  
E. Miclet ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Peptide Bond ◽  
Fine Tuning ◽  
Amide Bond ◽  
Donor Group ◽  
Hydrogen Bond Donor

CF2H-Pseudoprolines obtained from difluoroacetaldehyde hemiacetal and serine are stable proline surrogates. An intramolecular H-bond due to the CF2H group is promoting an exceptionally high content of cis-amide bond conformation.

Croconamides: a new dual hydrogen bond donating motif for anion recognition and organocatalysis

2017 ◽  
Vol 15 (13) ◽  
pp. 2784-2790 ◽  
Author(s):  
Anne Jeppesen ◽  
Bjarne E. Nielsen ◽  
Dennis Larsen ◽  
Olivia M. Akselsen ◽  
Theis I. Sølling ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Anion Recognition ◽  
Anion Receptors ◽  
The Family

We introduce bis-aryl croconamides as a new member in the family of dual hydrogen bonding anion receptors.

scholarly journals Superior anion induced shuttling behaviour exhibited by a halogen bonding two station rotaxane

2016 ◽  
Vol 7 (8) ◽  
pp. 5171-5180 ◽  
Author(s):  
Timothy A. Barendt ◽  
Sean W. Robinson ◽  
Paul D. Beer
Keyword(s):  
Hydrogen Bonding ◽  
Halogen Bond ◽  
Translational Motion ◽  
Anion Recognition ◽  
Halogen Bonding ◽  
Recognition Site ◽  
Naphthalene Diimide

Two bistable halogen and hydrogen bonding-naphthalene diimide [2]rotaxanes have been prepared and the system incorporating a halogen bond donor anion recognition site is demonstrated to exhibit superior anion induced translational motion of the macrocyclic wheel component relative to the hydrogen bonding analogue.

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