THE STUDY OF HYDROGEN BONDING AND RELATED PHENOMENA BY ULTRAVIOLET LIGHT ABSORPTION: PART I. INTRODUCTION

1958 ◽  
Vol 36 (1) ◽  
pp. 180-188 ◽  
Author(s):  
W. F. Forbes ◽  
J. F. Templeton
Keyword(s):  
Hydrogen Bonding ◽  
Environmental Factors ◽  
Environmental Effects ◽  
Light Absorption ◽  
Bond Formation ◽  
Benzoic Acids ◽  
Intermolecular Hydrogen Bonding ◽  
Dimer Formation ◽  
Factors Affecting ◽  
Solvent Molecules

Hydrogen bonding, which is known to give rise to dimer formation in benzoic acids and similar compounds, may affect solution spectra by intermolecular and by intramolecular bond formation. Generally environmental factors affecting absorption spectra can be conveniently divided into three types: intermolecular hydrogen bonding between solute molecules only; intermolecular hydrogen bonding between solute and solvent molecules; and environmental effects not involving the formation of hydrogen bonds.Distinct evidence for these types of interaction is deduced from ultraviolet spectra, and various implications of the spectral analyses are discussed.

THE STUDY OF HYDROGEN BONDING AND RELATED PHENOMENA BY ULTRAVIOLET LIGHT ABSORPTION: PART IV. INTERMOLECULAR HYDROGEN BONDING IN ANILINES AND PHENOLS

1960 ◽  
Vol 38 (6) ◽  
pp. 896-910 ◽  
Author(s):  
J. C. Dearden ◽  
W. F. Forbes
Keyword(s):  
Hydrogen Bonding ◽  
Ultraviolet Light ◽  
Light Absorption ◽  
Intermolecular Hydrogen Bonding ◽  
Solvent Molecules

Intermolecular hydrogen bonding in anilines and phenols can be subdivided into bonding involving solute molecules only, and into bonding involving both solute and solvent molecules. Interactions which do not involve hydrogen bonding are also possible between solute and solvent molecules. Spectral effects which may be associated with each of these interactions are described and discussed for anilines and phenols. By noting the effects of substituents on the various interactions, tentative conclusions can be deduced concerning the nature of these interactions.

A comparative study on the dynamics of epimeric 1-hydroxymethyl quinolizidines: II. The solvent and concentration dependence of the association properties

1988 ◽  
Vol 66 (9) ◽  
pp. 2166-2171 ◽  
Author(s):  
K. Kulińska ◽  
M. Wiewiórowski
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Intermolecular Hydrogen Bond ◽  
Chloroform Solution ◽  
Weak Acid ◽  
Hydroxyl Group ◽  
Intermolecular Hydrogen Bonding ◽  
Concentrated Solutions ◽  
Electron Pairs ◽  
Solvent Molecules

The homo and heteroassociation patterns of lupinine and epilupinine in different solvents and at various concentrations have been studied. In n-hexane, n-heptane, CCl4, and C2H4Cl2 solvents, lupinine monomers with an intramolecular OH … N hydrogen bond dominate over homoassociates with an OH … O′ intermolecular hydrogen bond even in concentrated solutions. Homoassociation of lupinine by intermolecular OH … N′ hydrogen bonding is observed only in saturated solutions. In chloroform solution any intermolecular homoassociation is effectively blocked because of significant affinity of chloroform molecules acting as a weak acid toward the free electron pairs of the oxygen atom from the hydroxyl group that would be otherwise engaged in intramolecular OH … N hydrogen bonding. Epilupinine in n-hexane, n-heptane, CCl4, C2H4Cl2, and chloroform solutions forms possible homoassociates both by OH … N′ and OH … O′ intermolecular hydrogen bonding. In dioxane-d8, DMSO, and D2O solvents both lupinine and epilupinine form heteroassociates with solvent molecules.

Breed and environmental factors affecting the reconception of indigenous beef cows in Botswana

1982 ◽  
Vol 35 (3) ◽  
pp. 413-420
Author(s):  
N. G. Buck ◽  
D. Light
Keyword(s):  
Environmental Factors ◽  
Environmental Effects ◽  
Reproductive Performance ◽  
Beef Cows ◽  
The Other ◽  
Factors Affecting ◽  
Lactating Cows ◽  
Management Interventions ◽  
Lower Fertility ◽  
Main Effects

ABSTRACTThe breeding records of 2710 lactating cows, of the Africander (1208), Tswana (542) and Tuli (960) breeds, were analysed to examine the effects of breed and environment on reconception. The reconception rate of Africander cows (0·56) was significantly lower than that of Tswana and Tuli cows (0·80 and 0·81 respectively) (P<0·01). The environmental effects of ranch, calving year, calving period and age/parity all had significant effects on reconception (P<0·01). Interactions between breed and the other main effects were all significant.The Africander is considered to be a breed of lower fertility than the other two Sanga breeds, the Tswana and Tuli, in Botswana. The results are discussed with respect to determining management interventions to improve cow reproductive performance.

Chiral anionic layers in tartramide spiroborate salts and variable solvation for [NR 4][B(TarNH2)2] (R = Et, Pr or Bu)

2020 ◽  
Vol 76 (7) ◽  
pp. 695-705
Author(s):  
Aristyo Soecipto ◽  
Lawrence W.-Y. Wong ◽  
Herman H.-Y. Sung ◽  
Ian D. Williams
Keyword(s):  
Hydrogen Bonding ◽  
Self Assembly ◽  
Interfacial Area ◽  
Intermolecular Hydrogen Bonding ◽  
Two Dimensional ◽  
Salt Hydrate ◽  
Anion Layer ◽  
Cation Layer ◽  
Layer Structures ◽  
Solvent Molecules

The spiroborate anion, namely, 2,3,7,8-tetracarboxamido-1,4,6,9-tetraoxa-5λ4-boraspiro[4.4]nonane, [B(TarNH2)2]−, derived from the diol L-tartramide TarNH2, [CH(O)(CONH2)]2, shows a novel self-assembly into two-dimensional (2D) layer structures in its salts with alkylammonium cations, [NR 4]+ (R = Et, Pr and Bu), and sparteinium, [HSpa]+, in which the cations and anions are segregated. The structures of four such salts are reported, namely, the tetrapropylazanium salt, C12H28N+·C8H12BN4O8 −, the tetraethylazanium salt hydrate, C8H20N+·C8H12BN4O8 −·6.375H2O, the tetrabutylazanium salt as the ethanol monosolvate hemihydrate, C16H36N+·C8H12BN4O8 −·C2H5OH·0.5H2O, and the sparteinium (7-aza-15-azoniatetracyclo[7.7.1.02,7.010,15]heptadecane) salt as the ethanol monosolvate, C15H27N2 +·C8H12BN4O8 −·C2H5OH. The 2D anion layers have preserved intermolecular hydrogen bonding between the amide groups and a typical metric repeat of around 10 × 15 Å. The constraint of matching the interfacial area organizes the cations into quite different solvated arrangements, i.e. the [NEt4] salt is highly hydrated with around 6.5H2O per cation, the [NPr4] salt apparently has a good metric match to the anion layer and is unsolvated, whilst the [NBu4] salt is intermediate and has EtOH and H2O in its cation layer, which is similar to the arrangement for the chiral [HSpa]+ cation. This family of salts shows highly organized chiral space and offers potential for the resolution of both chiral cations and neutral chiral solvent molecules.

THE STUDY OF HYDROGEN BONDING AND RELATED PHENOMENA BY ULTRAVIOLET LIGHT ABSORPTION: PART III. THE STRENGTH OF THE DIMERIC HYDROGEN BOND IN SUBSTITUTED BENZOIC ACIDS AS A MEASURE OF ELECTRONIC AND STERIC INTERACTIONS

1960 ◽  
Vol 38 (5) ◽  
pp. 728-735 ◽  
Author(s):  
W. F. Forbes ◽  
A. R. Knight ◽  
D. L. Coffen
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Concentration Dependence ◽  
Intramolecular Hydrogen Bond ◽  
Light Absorption ◽  
Benzoic Acids ◽  
Steric Interactions ◽  
Substituted Benzoic Acids ◽  
Intramolecular Hydrogen ◽  
Methoxybenzoic Acid

The strength of the intermolecular (dimeric) hydrogen bond in substituted benzoic acids, as estimated from the observed concentration dependence of the ultraviolet absorption spectra, is found to vary with the nature and the position of the substituent. The effects of a number of substituents on the strength of the dimeric hydrogen bond can be rationalized in terms of the usual electronic and steric interactions. The data indicate that o-methoxybenzoic acid forms a stronger intramolecular hydrogen bond than o-fluorobenzoic acid.

scholarly journals Palladium(II) complexes of a bridging amine bis(phenolate) ligand featuring κ2 and κ3 coordination modes

2019 ◽  
Vol 75 (8) ◽  
pp. 1265-1269 ◽  
Author(s):  
Brendan J. Graziano ◽  
Bradley M. Wile ◽  
Matthias Zeller
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Planar Geometry ◽  
Intermolecular Hydrogen Bonding ◽  
Coordination Modes ◽  
Methyl Methyl ◽  
Ethyl Methyl ◽  
Square Planar ◽  
Solvent Molecules ◽  
Insight Into

Bidentate and tridentate coordination of a 2,4-di-tert-butyl-substituted bridging amine bis(phenolate) ligand to a palladium(II) center are observed within the same crystal structure, namely dichlorido({6,6′-[(ethane-1,2-diylbis(methylazanediyl)]bis(methylene)}bis(2,4-di-tert-butylphenol))palladium(II) chlorido(2,4-di-tert-butyl-6-{[(2-{[(3,5-di-tert-butyl-2-hydroxyphenyl)methyl](methyl)amino}ethyl)(methyl)amino]methyl}phenolato)palladium(II) methanol 1.685-solvate 0.315-hydrate, [PdCl2(C34H56N2O2)][PdCl(C34H55N2O2)]·1.685CH3OH·0.315H2O. Both complexes exhibit a square-planar geometry, with unbound phenol moieties participating in intermolecular hydrogen bonding with co-crystallized water and methanol. The presence of both κ2 and κ3 coordination modes arising from the same solution suggest a dynamic process in which phenol donors may coordinate or dissociate from the metal center, and offers insight into catalyst speciation throughout Pd-mediated processes. The unit cell contains dichlorido({6,6′-[(ethane-1,2-diylbis(methylazanediyl)]bis(methylene)}bis(2,4-di-tert-butylphenol))palladium(II), {(L 2)PdCl2}, and chlorido(2,4-di-tert-butyl-6-{[(2-{[(3,5-di-tert-butyl-2-hydroxyphenyl)methyl](methyl)amino}ethyl)(methyl)amino]methyl}phenolato)palladium(II), {(L 2 X)PdCl}, molecules as well as fractional water and methanol solvent molecules.

THE STUDY OF HYDROGEN BONDING AND RELATED PHENOMENA BY ULTRAVIOLET LIGHT ABSORPTION: PART II. THE EFFECT OF SOLVENT–SOLUTE INTERACTIONS ON THE INTERMOLECULAR: HYDROGEN BOND IN BENZOIC ACIDS

1959 ◽  
Vol 37 (2) ◽  
pp. 334-340 ◽  
Author(s):  
W. F. Forbes ◽  
A. R. Knight
Keyword(s):  
Hydrogen Bonding ◽  
Intermolecular Hydrogen Bond ◽  
Solvent Mixtures ◽  
Benzoic Acids ◽  
Intermolecular Hydrogen Bonding ◽  
Absorption Bands ◽  
Effect Of Solvent ◽  
Concentration Dependences ◽  
Solute Interactions ◽  
Substituted Benzoic Acids

The concentration dependence of some electronic absorption bands, which has previously been ascribed to intermolecular hydrogen bonding, is reinvestigated. The concentration dependences are compared for a number of substituted benzoic acids in inert solvents, and in solvent mixtures containing various amounts of ether. The results are discussed in terms of current theories of hydrogen bonding.

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