scholarly journals Low-dimensional hydrogen-bonded structures in the 1:1 and 1:2 proton-transfer compounds of 4,5-dichlorophthalic acid with the aliphatic Lewis bases triethylamine, diethylamine,n-butylamine and piperidine

2010 ◽  
Vol 66 (7) ◽  
pp. o374-o380 ◽  
Author(s):  
Graham Smith ◽  
Urs D. Wermuth
Keyword(s):  
Proton Transfer ◽  
Lewis Bases ◽  
Low Dimensional ◽  
Proton Transfer Compounds ◽  
Hydrogen Bonded

scholarly journals Zero-, one- and two-dimensional hydrogen-bonded structures in the 1:1 proton-transfer compounds of 4,5-dichlorophthalic acid with the monocyclic heteroaromatic Lewis bases 2-aminopyrimidine, nicotinamide and isonicotinamide

2009 ◽  
Vol 65 (3) ◽  
pp. o103-o107 ◽  
Author(s):  
Graham Smith ◽  
Urs D. Wermuth ◽  
Jonathan M. White
Keyword(s):  
Proton Transfer ◽  
Lewis Base ◽  
Two Dimensional ◽  
Compound I ◽  
Lewis Bases ◽  
Amide Carbonyl ◽  
Low Dimensionality ◽  
Low Dimensional ◽  
Proton Transfer Compounds ◽  
Hydrogen Bonded

The structures of the anhydrous 1:1 proton-transfer compounds of 4,5-dichlorophthalic acid (DCPA) with the monocyclic heteroaromatic Lewis bases 2-aminopyrimidine, 3-(aminocarbonyl)pyridine (nicotinamide) and 4-(aminocarbonyl)pyridine (isonicotinamide), namely 2-aminopyrimidinium 2-carboxy-4,5-dichlorobenzoate, C4H6N3+·C8H3Cl2O4−, (I), 3-(aminocarbonyl)pyridinium 2-carboxy-4,5-dichlorobenzoate, C6H7N2O+·C8H3Cl2O4−, (II), and the unusual salt adduct 4-(aminocarbonyl)pyridinium 2-carboxy-4,5-dichlorobenzoate–methyl 2-carboxy-4,5-dichlorobenzoate (1/1), C6H7N2O+·C8H3Cl2O4−·C9H6Cl2O4, (III), have been determined at 130 K. Compound (I) forms discrete centrosymmetric hydrogen-bonded cyclic bis(cation–anion) units having bothR22(8) andR12(4) N—H...O interactions. In (II), the primary N—H...O-linked cation–anion units are extended into a two-dimensional sheet structureviaamide–carboxyl and amide–carbonyl N—H...O interactions. The structure of (III) reveals the presence of an unusual and unexpected self-synthesized methyl monoester of the acid as an adduct molecule, giving one-dimensional hydrogen-bonded chains. In all three structures, the hydrogen phthalate anions are essentially planar with short intramolecular carboxyl–carboxylate O—H...O hydrogen bonds [O...O = 2.393 (8)–2.410 (2) Å]. This work provides examples of low-dimensional 1:1 hydrogen-bonded DCPA structure types, and includes the first example of a discrete cyclic `heterotetramer.' This low dimensionality in the structures of the 1:1 aromatic Lewis base salts of the parent acid is generally associated with the planar DCPA anion species.

scholarly journals 5-Nitrosalicylic Acid and its Proton-Transfer Compounds with Aliphatic Lewis Bases

2005 ◽  
Vol 58 (1) ◽  
pp. 47 ◽  
Author(s):  
Graham Smith ◽  
Andy W. Hartono ◽  
Urs D. Wermuth ◽  
Peter C. Healy ◽  
Jonathan M. White ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Proton Transfer ◽  
Lewis Base ◽  
Unusual Structure ◽  
Lewis Bases ◽  
Carboxylate Oxygen ◽  
Hydrogen Bonding Interactions ◽  
Polymer Compound ◽  
Proton Transfer Compounds ◽  
Centrosymmetric Dimers

The crystal structures of the proton-transfer compounds of 5-nitrosalicylic acid (5-nsa) with morpholine (morph), hexamethylenetetramine (hmt), and ethylenediamine (en) have been determined and their solid-state packing structures described. The compounds are [(morph)+(5-nsa)–] 1, [(hmt)+(5-nsa)–·H2O] 2, and [(en)2+2(5-nsa)–·H2O] 3. In all compounds, protonation of the hetero-nitrogen of the Lewis base occurs. With 1, the 5-nsa anions and the morpholine cations lie, respectively, in or across crystallographic mirror planes and are linked within the planes by hydrogen-bonding interactions through the aminium group and the carboxylic and phenolic oxygens of the anionic 5-nsa species giving a two-dimensional sheet polymer. Compound 2 is an unusual structure with the planar 5-nsa anions lying within pseudo mirror planes and cyclically linked by duplex water bridges through a single carboxylate oxygen into centrosymmetric dimers. The hmt cation molecules are disordered across the pseudo mirror and are strongly linked by N+–H···O hydrogen bonds only to the water molecules with peripheral weak hmt C–H···O hydrogen bonds extending the dimer within and between the dimer planes. Compound 3 is a network polymer comprised of the 5-nsa anions, the en dianions, and the water molecule in an extensive hydrogen-bonded structure.

scholarly journals Molecular Recognition in Proton-Transfer Compounds of Brucine with Achiral Substituted Salicylic Acid Analogues

2006 ◽  
Vol 59 (5) ◽  
pp. 320 ◽  
Author(s):  
Graham Smith ◽  
Urs D. Wermuth ◽  
Peter C. Healy ◽  
Jonathan M. White
Keyword(s):  
Proton Transfer ◽  
Three Dimensional ◽  
Water Molecules ◽  
Sulfosalicylic Acid ◽  
X Ray ◽  
X Ray Crystallography ◽  
Guest Species ◽  
Substituted Benzoic Acids ◽  
Proton Transfer Compounds ◽  
Hydrogen Bonded

The 1:1 proton-transfer brucinium compounds from the reaction of the alkaloid brucine with 5-nitrosalicylic acid, 3,5-dinitrosalicylic acid, and 5-sulfosalicylic acid, namely anhydrous brucinium 5-nitrosalicylate (1), brucinium 3,5-dinitrosalicylate monohydrate (2), and brucinium 5-sulfosalicylate trihydrate (3) have been prepared and their crystal structures determined by X-ray crystallography. All structures further demonstrate the selectivity of brucine for meta-substituted benzoic acids and comprise three-dimensional hydrogen-bonded framework polymers. Two of the compounds (1 and 3) have the previously described undulating brucine sheet host-substructures which incorporate interstitially hydrogen-bonded salicylate anion guest species and additionally in 3 the water molecules of solvation. The structure of 2 differs in having a three-centre brucinium–salicylate anion bidentate N+–H···O(carboxyl) hydrogen-bonding association linking the species through interstitial associations involving also the water molecules of solvation. A review of the crystallographic structural literature on strychnine and brucine is also given.

scholarly journals Significance of nuclear quantum effects in hydrogen bonded molecular chains

2021 ◽  
Author(s):  
Ales Cahlik ◽  
Jack Hellerstedt ◽  
Jesus Mendieta-Moreno ◽  
Martin Švec ◽  
Vijai Santhini ◽  
...  
Keyword(s):  
Proton Transfer ◽  
Mechanical Stability ◽  
Dominant Role ◽  
Zero Point ◽  
Quantum Effects ◽  
Molecular Networks ◽  
Hydrogen Bonded Systems ◽  
Low Dimensional ◽  
Nuclear Quantum Effects ◽  
Hydrogen Bonded

Abstract In hydrogen bonded systems, nuclear quantum effects such as zero-point motion and tunneling can significantly affect their material properties through underlying physical and chemical processes. Presently, direct observation of the influence of nuclear quantum effects on the strength of hydrogen bonds with resulting structural and electronic implications remains elusive, leaving opportunities for deeper understanding to harness their fascinating properties. We studied hydrogen-bonded one-dimensional quinonediimine molecular networks which may adopt two isomeric electronic configurations via proton transfer. Herein, we demonstrate that concerted proton transfer promotes a delocalization of π-electrons along the molecular chain, which enhances the cohesive energy between molecular units, increasing the mechanical stability of the chain and giving rise to new electronic in-gap states localized at the ends. These findings demonstrate the identification of a new class of isomeric hydrogen bonded molecular systems where nuclear quantum effects play a dominant role in establishing their chemical and physical properties. We anticipate that this work will open new research directions towards the control of mechanical and electronic properties of low-dimensional molecular materials via concerted proton tunneling.

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