Spectrophotometric determination of equilibrium constants in solution☆

McBryde, W. A. E.

doi:10.1016/0039-9140(74)80130-x

Cited by 84 publications

(19 citation statements)

References 41 publications

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“…The isosbestic point at 250 nm in Fig. 5 indicates that only two species contribute to the absorbance changes (14), the monomer and the fully formed complex. Intermediate forms are not present in significant concentration.…”

Section: Figmentioning

confidence: 98%

Spectroscopic and Kinetic Characterization of Eosin–5-Maleimide

Schopfer

Salhany

1998

Analytical Biochemistry

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Section: Figmentioning

confidence: 98%

Spectroscopic and Kinetic Characterization of Eosin–5-Maleimide

Schopfer

Salhany

1998

Analytical Biochemistry

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“…[35] Knowledge of the precise values of K X is crucially important, for it determines both the ATRP catalyst activity (Scheme 2) and the amount of deactivator present in the system (eq (2)) and therefore the degree of polymerization control. [37] The equilibrium constant of halide anion coordination can be measured by spectroscopic means, [38] as described in the literature for bpy-based ATRP deactivators in several protic solvents. [35] The refined values can be easily determined using programs such as Hyperquad.…”

mentioning

confidence: 99%

Competitive Equilibria in Atom Transfer Radical Polymerization

Tsarevsky¹,

Braunecker²,

Vacca³

et al. 2007

Macromolecular Symposia

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Summary: With the recent development of new initiation techniques in atom transfer radical polymerization (ATRP) that allow catalysts to be employed at unprecedented low concentrations ($10 ppm), a thorough understanding of competitive equilibria that can affect catalyst performance is becoming increasingly important. Such mechanistic considerations are discussed herein, including i) factors affecting the position of the ATRP equilibrium; ii) dissociation of the ATRP catalyst at high dilution and loss of deactivator due to halide dissociation; iii) conditional stability constants as related to competitive monomer, solvent, and reducing agent complexation as well as ligand selection with respect to protonation in acidic media; and iv) competitive equilibria involving electron transfer reactions, including the radical oxidation to carbocations or reduction to carbanions, radical coordination to the metal catalyst, and disproportionation of the Cu I -based ATRP activator.

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“…The equilibrium constant in the mixture at different concentrations can be calculated using spectroscopic data. 14,15 In the system (2Cl-pyridine C methanol), both C-35 Cl and C-37 Cl are participating in the hydrogen bonding as revealed by the intensity ratio of C-35 Cl to C-37 Cl at different concentrations presented in Fig. 6.…”

Section: Equilibrium Constant In (2cl-pyridine + Methanol) Mixturementioning

confidence: 98%

Study of vibrational dephasing of CCl stretching mode of 2Cl‐pyridine and 3Cl‐pyridine in methanol environment by polarized Raman study and DFT calculations

Singh

Srivastava

Ojha

et al. 2006

J Raman Spectroscopy

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Raman spectra of [2Cl-pyridine (2Cl-p) + methanol] and [3Cl-pyridine (3Cl-p) + methanol] mixtureswere recorded in the region 360-480 cm −1 and the concentration dependence of linewidths and peak positions of the isotropic part of the Raman scattered radiation for the C-Cl stretching mode were studied in the light of the existing models. The analysis of the results revealed that concentration fluctuation and diffusion simultaneously play a role in the dephasing of the C-Cl stretching mode. The optimized structures of the reference systems, 2Cl-p and 3-Cl-p, and their various complexes with methanol were calculated by density functional theory (DFT) geometry optimization technique using B3LYP functional and 6-31+G(d,p) basis set. On the basis of the results of geometry optimization and energy minimization calculation, we propose that the complex formed as a result of hydrogen bonding of one 3Cl-p molecule with three methanol molecules is more stable than the one formed by one 3Cl-p molecule and two methanol molecules. This study presents an explanation of changes in spectral features of ortho/meta Cl-substituted pyridines supported by DFT derived optimized geometries. Equilibrium constants have been obtained from the spectral data for one of the systems (2Cl-pyridine + methanol).

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Spectrophotometric determination of equilibrium constants in solution☆

Cited by 84 publications

References 41 publications

Spectroscopic and Kinetic Characterization of Eosin–5-Maleimide

Spectroscopic and Kinetic Characterization of Eosin–5-Maleimide

Competitive Equilibria in Atom Transfer Radical Polymerization

Study of vibrational dephasing of CCl stretching mode of 2Cl‐pyridine and 3Cl‐pyridine in methanol environment by polarized Raman study and DFT calculations

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