Theoretical study of the basicity of alkyl amines in vacuo and in different solvents: a density functional theory approach

Safi, Bennasser; Choho, K.; Proft, Frank De; Geerlings, Pau̧l

doi:10.1016/s0009-2614(98)01355-4

Cited by 35 publications

(47 citation statements)

References 27 publications

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“…This can be considered as the decrease of local softness at the basic site as a consequence of electron-donating substituent effects at the respective center. But for the (CH 3 ) 3 CNH 2 , the electrophilicity index ( k Ϫ ) at nitrogen site exhibits the same trend that was obtained by Safi et al [30] and Yang and Mortier [38]. This result is also in good agreement with that of Contreras and co workers [35].…”

Section: Figuresupporting

confidence: 88%

“…A series of DFT-based properties such as the electronegativity, hardness, and softness of alkyl amines are analyzed by Safi and coworkers [30] in the gas phase and in different solvents. The effect of solvent on electrophilicity and nucleophilicity has been studied [20,21].…”

Section: Figurementioning

confidence: 99%

“…An inverse relationship between f N Ϫ at N site and the basicities has been observed [35]. Similarly, relative protonation energies, Gibbs free energy for protonation of base, and charge transfer upon protonation of the amine have been used to derive information about basicities of various aliphatic amines in gas phase and solution phase [30]. The values of k Ϫ at NϪ site of all the molecules are given in Table III.…”

Section: Com]mentioning

confidence: 99%

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DFT study of some aliphatic amines using generalized philicity concept

Chattaraj

Sarkar

Parthasarathi

et al. 2004

Int J of Quantum Chemistry

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An attempt has been made to test the usefulness of the generalized philicity concept of Chattaraj et al. through gas-and solution-phase density functional theory calculations on some aliphatic amines. Local philicity provides important clues about the reactivity and selectivity, and it contains almost all the known global and local chemical reactivity parameters. Local philicity provides the Fukui function, but the converse is not true. We have also studied the effect of solvent (water) on reactivity. The philicities are in general less in solvent than in the gas phase, but the total energy and dipole moment are higher in the solvent medium.

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Section: Figuresupporting

confidence: 88%

Section: Figurementioning

confidence: 99%

Section: Com]mentioning

confidence: 99%

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DFT study of some aliphatic amines using generalized philicity concept

Chattaraj

Sarkar

Parthasarathi

et al. 2004

Int J of Quantum Chemistry

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“…By increasing the methylation levels on the amines, despite increasing the inductive effect and producing increased basicity in the gas phase or in apolar solvents, the state is different in protic (in this case H 2 O) and aprotic polar solvents where a reduction in the solvation energy of the conjugate acid results in lower stabilization levels and a consequent decrease in basicity (41). Hence, charge levels will be lower at any given pH when tertiary amines are compared with secondary ones.…”

Section: Resultsmentioning

confidence: 99%

From biosilicification to tailored materials: Optimizing hydrophobic domains and resistance to protonation of polyamines

Belton

Patwardhan

Annenkov

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

134

181

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Considerable research has been directed toward identifying the mechanisms involved in biosilicification to understand and possibly mimic the process for the production of superior silica-based materials while simultaneously minimizing pollution and energy costs. Molecules isolated from diatoms and, most recently sponges, thought to be key to this process contain polyamines with a propylamine backbone and variable levels of methylation. In a chemical approach to understanding the role of amine (especially propylamine) structures in silicification we have explored three key structural features: (i) the degree of polymerization, (ii) the level of amine methylation, and (iii) the size of the amine chain spacers. In this article, we show that there are two factors critical to their function: the ability of the amines to produce microemulsions and the presence of charged and uncharged amine groups within a molecule, with the latter feature helping to catalyze silicic acid condensation by a proton donor/acceptor mechanism. The understanding of amine-silicate interactions obtained from this study has enabled the controlled preparation of hollow and nonporous siliceous materials under mild conditions (circumneutral pH, room temperature, and in all aqueous systems) possibly compatible with the conditions used by biosystems. The ''rules'' identified from our study were further used predictively to modulate the activity of a given amine. We believe that the outcomes of the present contribution will form the basis for an approach to controlling the growth of inorganic materials by using tailor-made organic molecules.bioinspired materials ͉ biosilica ͉ hollow particles T he commercialization of siliceous materials has generated a multibillion pound industry with the value of precipitated silica products alone estimated to have reached 1.4 billion pounds by the year 2006 (1). This value largely depends on the ability to produce silica for specific applications through control of surface chemistry and morphology during the condensation and aggregation process. Industrial processes involved in the production of high-value siliceous materials typically involve harsh conditions of high temperature and acidity or basicity, environmentally damaging waste streams, and often toxic silicate precursors. These processes also generally exert poor chemical and morphological control over the materials produced. In comparison, natural silica production in organisms such as sponges, diatoms, and radiolaria occurs under biologically benign conditions and produces silica of exquisite form and function, all from a monosilicic acid source of only a few parts per million in concentration (2). Considerable research has been directed toward identifying the mechanisms involved in the biosilicification process to understand and possibly mimic the process to allow us to produce superior materials without the attendant pollution and high-energy usage (3, 4).Studies of the processes associated with the formation of siliceous diatom shells (thecae) have i...

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“…DFT has previously been used to study the influence of N-methylation on structural properties of transition-metal complexes with cyclic polyaza ligands [11g,28] and to describe the properties of polyamines, such as their basicity in both gas-phase [29] and solvent models. [30] …”

Section: Introductionmentioning

confidence: 99%

Affinity of Polypyridines Towards Cd^II and Co^II Ions: a Thermodynamic and DFT Study

et al. 2006

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CdII and CoII complex formation with pyridine (py), 2,2′‐bipyridine (bipy), 2,2′6′,2″‐terpyridine (terpy), 2‐(aminomethyl)pyridine (amp), and bis[(2‐pyridyl)methyl]amine (dpma) was studied at 298 K in the aprotic solvent dimethyl sulfoxide (DMSO) and in an ionic medium set to 0.1 mol dm–3 with Et4NClO4 in anaerobic conditions. Potentiometric, UV/Vis spectrophotometric, and calorimetric measurements were carried out to obtain the thermodynamic parameters of the systems investigated. Enthalpy‐stabilized mononuclear MLj complexes are formed, whereas entropy changes counteract complex formation. These results are discussed in terms of different basicities, steric requirements, and solvation, of both the ligands and the resulting complexes. Density functional theory (DFT) calculations were carried out in order to obtain structural information and binding energies in vacuo. The DFT results are correlated with the solution studies. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

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Theoretical study of the basicity of alkyl amines in vacuo and in different solvents: a density functional theory approach

Cited by 35 publications

References 27 publications

DFT study of some aliphatic amines using generalized philicity concept

DFT study of some aliphatic amines using generalized philicity concept

From biosilicification to tailored materials: Optimizing hydrophobic domains and resistance to protonation of polyamines

Affinity of Polypyridines Towards Cd^II and Co^II Ions: a Thermodynamic and DFT Study

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Theoretical study of the basicity of alkyl amines in vacuo and in different solvents: a density functional theory approach

Cited by 35 publications

References 27 publications

DFT study of some aliphatic amines using generalized philicity concept

DFT study of some aliphatic amines using generalized philicity concept

From biosilicification to tailored materials: Optimizing hydrophobic domains and resistance to protonation of polyamines

Affinity of Polypyridines Towards CdII and CoII Ions: a Thermodynamic and DFT Study

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Affinity of Polypyridines Towards Cd^II and Co^II Ions: a Thermodynamic and DFT Study