Fundamentals of the zwitterionic hydrophilic group

Laughlin, Robert G.

doi:10.1021/la00053a006

Cited by 145 publications

(125 citation statements)

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“…Mesoionic compounds can be only presented by canonical formulas via a set of mesomeric structures that contain formally cationic and anionic sites; yet, they do not carry separate charges but dispose only of a high dipole moment. Generally, they are not even effective hydrophilic groups [7,8]. Ylides are 1,2-dipolar compounds with a semi-polar bond, which may be represented by canonical formulas with formally separate positive and negative charges on neighbouring atom.…”

Section: Scheme1 Simplistic Model Of Polyampholytes (Left) and Polyzmentioning

confidence: 99%

“…Thus, hydrophilicity (and also hygroscopy) of the anionic groups decreases in the order -COO 7,8,79]. Alkoxydicyanoethenolates (XII) are the most acidic and the least hydrophilic anionic groups, so that the derived polyzwitterions are typically not water soluble [66,69].…”

Section: Zwitterionic Moieties Realized In Polyzwitterions and Their mentioning

confidence: 99%

“…Therefore, polyampholytes behave mostly either as polyanionic or as polycationic species, whereas polyzwitterions due to their overall charge neutrality exhibit a different, hybrid-like property profile. On the one hand, strong Coulomb interactions prevail in polyzwitterions, which thus generally exhibit high hydrophilicity [3,7]. On the other hand, polyzwitterions do not show the typical polyelectrolyte effects, but their behavior shares many similarities with polar non-ionic polymers [5].…”

Section: Introductionmentioning

confidence: 99%

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Structures and Synthesis of Zwitterionic Polymers

2014

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Abstract:The structures and synthesis of polyzwitterions ("polybetaines") are reviewed, emphasizing the literature of the past decade. Particular attention is given to the general challenges faced, and to successful strategies to obtain polymers with a true balance of permanent cationic and anionic groups, thus resulting in an overall zero charge. Also, the progress due to applying new methodologies from general polymer synthesis, such as controlled polymerization methods or the use of "click" chemical reactions is presented. Furthermore, the emerging topic of responsive ("smart") polyzwitterions is addressed. The considerations and critical discussions are illustrated by typical examples.

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Section: Scheme1 Simplistic Model Of Polyampholytes (Left) and Polyzmentioning

confidence: 99%

Section: Zwitterionic Moieties Realized In Polyzwitterions and Their mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Structures and Synthesis of Zwitterionic Polymers

2014

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“…For a fixed length of both hydrophobic tails the cmc increases with the spacer length until it reaches a maximum value, and then the value decreases [262,265,266]. Furthermore, gemini surfactants with different headgroups -so-called heterogemini [267][268][269]-show very interesting properties; among these geminis we find zwitterionic surfactants which present an intermediate nature between ionic and non-ionic surfactants, and depending on the type of the head groups they may show pH-dependent properties [270]. Aqueous solutions of some dimeric surfactants with short spacers show a very high viscosity at relative low concentrations and/or display viscoelasticity and shear induced viscoelasticity [271].…”

Section: Gemini Surfactantsmentioning

confidence: 99%

The formation of host–guest complexes between surfactants and cyclodextrins

Valente

Söderman

2014

Advances in Colloid and Interface Science

184

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Cyclodextrins are able to act as host molecules in supramolecular chemistry with applications ranging from pharmaceutics to detergency. Among guest molecules surfactants play an important role with both fundamental and practical applications. The formation of cyclodextrin/surfactant host-guest compounds leads to an increase in the critical micelle concentration and in the solubility of surfactants. The possibility of changing the balance between several intermolecular forces, and thus allowing the study of, e.g., dehydration and steric hindrance effects upon association, makes surfactants ideal guest molecules for fundamental studies. Therefore, these systems allow for obtaining a deep insight into the host-guest association mechanism. In this paper, we review the influence on the thermodynamic properties of CD-surfactant association by highlighting the effect of different surfactant architectures (single tail, double-tailed, gemini and bolaform), with special emphasis on cationic surfactants. This is complemented with an assessment of the most common analytical techniques used to follow the association process. The applied methods for computation of the association stoichiometry and stability constants are also reviewed and discussed; this is an important point since there are significant discrepancies and scattered data for similar systems in the literature.In general, the surfactant-cyclodextrin association is treated without reference to the kinetics of the process. However, there are several examples where the kinetics of the process can be investigated, in particular those where volumes of the CD cavity and surfactant (either the tail or in special cases the head group) are similar in magnitude.This will also be critically reviewed.

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“…Zwitterions contain a quaternary nitrogen atom and a carboxylate group, separated by one or more carbon atoms. The ammonium group is inert as a hydrogen bond center, whereas the carboxylate group is basic [4,5]. At normal conditions betaines crystallize as hydrates, because of the strong H-acceptor carboxylic group and no acidic H-donors.…”

Section: Introductionmentioning

confidence: 99%

Conformational flexibility and pseudosymmetric aggregation in a betainium salt hydrate

et al. 2016

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The cation of 3-(trimethylammonium)-benzoic acid exhibits a considerable conformational flexibility connected to the orientation of carboxyl group, coupled to the proton position, and rotations of the trimethylammonium group. This conformational flexibility considerably affects the aggregation of ions and molecules of 3-(trimethylammonium)-benzoic acid iodide hydrate, which crystallizes in a lowsymmetry structure with four symmetry-independent formula units (monoclinic space group Pc, Z' = 4, model I). However this structure approximates the symmetry of space group P2 1 / c in the same unit cell (Z' = 2, model II), and also even a still more highly symmetric structure of space group P2 1 /c in a half-smaller unit cell (Z' = 1, model III). The independent formula units are differentiated by the conformations of trimethylammonium groups (ordered in model I, but disordered in models II and III), conformations of the carboxyl groups and positions of OH···O bonded water molecules (ordered in molecules I and II, and disordered in model III), while the bulks of the cations and iodide anions are consistent for all models. While the calorimetric study and varied-temperature structural determinations exclude phase transitions of the highly pseudosymmetric model I. This pseudosymmetry is independent of temperature between 100 K and the m.p. at 463 K, and illustrates subtle structural effects leading complex molecular aggregation in the crystal. Theoretical computations confirm the low energy differences between the conformers.

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Fundamentals of the zwitterionic hydrophilic group

Cited by 145 publications

References 2 publications

Structures and Synthesis of Zwitterionic Polymers

Structures and Synthesis of Zwitterionic Polymers

The formation of host–guest complexes between surfactants and cyclodextrins

Conformational flexibility and pseudosymmetric aggregation in a betainium salt hydrate

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