Kinetics and mechanism of the interaction of adenosine with cis‐diaqua(cis‐1,2‐diaminocyclohexane)platinum(II) perchlorate in aqueous medium

The kinetics of the interaction of adenosine with cis‐[Pt(cis‐dach)(OH₂)₂]²⁺ (dach = diaminocyclohexane) was studied spectrophotometrically as a function of [cis‐[Pt(cis‐dach)(OH₂)₂]²⁺], [adenosine], and temperature at a particular pH (4.0), where the substrate complex exists predominantly as the diaqua species and the ligand adenosine exists as a neutral molecule. The substitution reaction shows two consecutive steps: the first is the ligand‐assisted anation followed by a chelation step. The activation parameters for both the steps have been evaluated using Eyring equation. The low negative value of ΔH^≠₁ (43.1 ± 1.3 kJ mol^?1) and the large negative value of ΔS^≠₁ (?177 ± 4 J K^?1 mol^?1) along with ΔH^≠₂ (47.9 ± 1.8 kJ mol^?1) and ΔS^≠₂ (?181 ± 6 J K^?1 mol^?1) indicate an associative mode of activation for both the aqua ligand substitution processes. The kinetic study was substantiated by infrared and electrospray ionization mass spectroscopic analysis. © 2011 Wiley Peiodicals, Inc. Int J Chem Kinet 43: 219–229, 2011     

Kinetics of substitution of aqua ligands from cis‐diaqua (ethylenediamine)platinum(II) perchlorate by L‐asparagine in aqueous medium

The kinetics of the interaction of L ‐asparagine with [Pt(ethylenediamine)(H₂O)₂]²⁺ have been studied spectrophotometrically as a function of [Pt(ethylenediamine)(H₂O)₂²⁺], [L ‐asparagine], and temperature at pH 4.0, where the substrate complex exists predominantly as the diaqua species and L ‐asparagine as the zwitterion. The substitution reaction shows two consecutive steps: the first step is the ligand‐assisted anation and the second one is the chelation step. Activation parameters for both the steps have been calculated using Eyring equation. The low ΔH₁^≠ (43.59 ± 0.96 kJ mol^?1) and large negative values of ΔS₁^≠ (?116.98 ± 2.9 J K^?1 mol^?1) as well as ΔH₂^≠ (33.78 ± 0.51 kJ mol^?1) and ΔS₂^≠ (?221.43 ± 1.57 J K^?1 mol^?1) indicate an associative mode of activation for both the aqua ligand substitution processes. © 2003 Wiley Periodicals, Inc. Int J Chem Kinet 35: 252–259, 2003     

Substitution and Isomerization of Nitrite Ion at a Cobalt(III) Centre Having a Coordinated Pentadentate Ligand with Two Nitrogen and Three Sulfur Donor Atoms

The influence of placing thioether linkages trans to a site of nitrito substitution and spontaneous nitrito-tonitro isomerization is reported for the [CoQS(H₂O)]³⁺ cation where QS is 1,11-diamino-3,6,9-trithiaundecane. Preparation and characterization is described for the aqua and nitrito complexes. Rate data for the substitution process is presented at 17.7, 25.0 and 35.0°C. It is consistent with the mechanism first proposed by Basolo and Pearson in which N₂O₃ is the nitrosation agent. [CoQS(H₂O)]³⁺ is three hundred times more reactive than [Co(NH₃)₅H₂O]³⁺ under identical conditions. Isomerization is dramatically slower than the conversion of [CoQS(H₂O)³⁺ to [CoQS(ONO)]²⁺. The isomerization process was studied at 5 wavelengths, 3 temperatures and various conditions of acid and nitrite ion at an ionic strength of 0.11–0.60 M. Studies at 25°C give k_isom = 1.21 ± 0.12 × 10^?4 sec ^?1. Similar determinations at 17.7 and 35.0°C give k_isom = 3.84 ± 0.65 × 10^?5 sec^?1 and 3.59 ± 0.13 × 10^?4 sec^?1 respectively. The thermodynamic activation parameters ΔH^≠, ΔG^≠, and ΔS^≠ obtained from an Eyring plot gives ΔH^≠ = 111.3 kJ/mol, ΔS^≠ = + 53 J/molK and ΔG^≠ = 95.4 kJ/mol. These results are discussed in the context of present knowledge and experience with other cobalt(III) ligand systems.     

Kinetics and mechanism of interaction of Pt(II) complex with bio-active ligands and in vitro Pt(II)-sulfur adduct formation in aqueous medium: bio-activity and computational study

Kinetics of interaction between [Pt(pic)(H₂O)₂](ClO₄)₂, 2 (where pic = 2-aminomethylpyridine) with the selected ligands DL-methionine (DL-meth) and DL-penicillamine (DL-pen) have been studied spectrophotometrically in aqueous medium separately as a function of [2] as well as [ligand], pH and temperature at constant ionic strength. The association equilibrium constants (K_E) for the outer sphere complex formation have been evaluated together with the rate constants for the two subsequent steps. Activation parameters (enthalpy of activation ΔH^≠ and entropy of activation ΔS^≠) were calculated from the Eyring equation. An associative mechanism of substitution is proposed for both reactions on the basis of the kinetic observations, evaluated activation parameters, and spectroscopic data. Structural optimizations, HOMO-LUMO energy calculation, and Natural Bond Orbital (NBO) analysis of 2–4 were carried out with Density Functional Theory. Bonding mode of thiol and thio-ether is confirmed by spectroscopic analyses and NBO calculation. Cytotoxic properties of 2–4 were explored on A549 carcinoma cell lines; DNA-binding properties of the complexes were also investigated by gel electrophoresis.     

铀(Ⅵ)与不对称希夫碱配合物的合成和热分解反应动力学

邻苯二胺与5－氯－2－羟基二苯酮、邻香草醛作用合成了一种不对称希夫碱配体C₂₇H₂₁N₂O₃Cl（H₂L）。在正丁醇和甲醇体系中硝酸铀酰与该配体反应合成了一种固体希夫碱配合物[UO₂(HL)(NO₃)(H₂O)]·H₂O。通过元素分析、IR、UV、¹H NMR、TG-DTG及摩尔电导率分析等手段对合成的配合物进行了表征,用非等温热重法研究了铀(Ⅵ)配合物的热分解反应动力学,推断出第三步热分解的动力学方程为：d α /d t = A · e^{- E/RT} ·3/2[(1- α )^-1/3-1]^-1,得到了动力学参数E和A。并计算出了活化熵△S^¹和活化吉布斯自由能△G^¹。     

Mechanistic Aspects of Ligand Substitution on the Hydroxopentaaquarhodium(III) Ion in Aqueous Solution by Sulfur‐Containing Bioactive Ligands

The kinetics of the interactions between three sulfur‐containing ligands, thioglycolic acid, 2‐thiouracil, glutathione, and the title complex, have been studied spectrophotometrically in aqueous medium as a function of the concentrations of the ligands, temperature, and pH at constant ionic strength. The reactions follow a two‐step process in which the first step is ligand‐dependent and the second step is ligand‐independent chelation. Rate constants (k₁ ～10^?3 s^?1 and k₂ ～10^?5 s^?1) and activation parameters (for thioglycolic acid: ΔH₁^≠ = 22.4 ± 3.0 kJ mol^?1, ΔS₁^≠ = ?220 ± 11 J K^?1 mol^?1, ΔH₂^≠ = 38.5 ± 1.3 kJ mol^?1, ΔS₂^≠ = ?204 ± 4 J K^?1 mol^?1; for 2‐thiouracil: ΔH₁^≠ = 42.2 ± 2.0 kJ mol^?1, ΔS₁^≠ = ?169 ± 6 J K^?1 mol^?1, ΔH₂^≠ = 66.1 ± 0.5 kJ mol^?1, ΔS₂^≠ = ?124 ± 2 J K^?1 mol^?1; for glutathione: ΔH₁^≠ = 47.2 ± 1.7 kJ mol^?1, ΔS₁^≠ = ?155 ± 5 J K^?1mol^?1, ΔH₂^≠ = 73.5 ± 1.1 kJ mol^?1, ΔS₂^≠ = ?105 ± 3 J K^?1 mol^?1) were calculated. Based on the kinetic and activation parameters, an associative interchange mechanism is proposed for the interaction processes. The products of the reactions have been characterized from IR and ESI mass spectroscopic analysis. A rate law involving the outer sphere association complex formation has been established as      

1H NMR Study of Hindered Internal Rotation of Tetramethylthiuram Disulfide in Binary Dimethyl Sulfoxide‐Chloroform Mixtures

Hindered internal rotation about the C‐N single bonds joining the thiuram disulfide was studied by ¹H NMR complete line‐shaped analysis in different dimethyl sulfoxide‐chloroform (DMSO‐CDCl₃) mixtures. From the temperature dependence of methyls proton spectra, activation parameters (E_a, ΔH^≠, ΔS^≠, and ΔG^≠) were obtained. The Arrhenius plots showed a distinct isokinetic temperature at about 35 °C at which the exchange rate is more or less independent of the solvent composition. The resulting ΔH^≠ against TΔS^≠ plot showed a firmly good linear correlation, indicating the existence of an enthalpy‐entropy composition in an exchange process.     

Cobaltchelate als Hydrierkatalysatoren. II). Hydridbildung beim [Co(dmgH)2]- und [Co(dpnH)]+ -Komplex

Cobalt Chelates for Hydrogenation Catalysts. II. Hydride Formation with [Co(dmgH)₂] and [Co(dpnH)]⁺ In the presence of benzil as scavanger for the hydridocomplexes [Co(dpnH)]⁺ and [Co(dmgH)₂] the hydride formation in water/n-propanol (50% v/v) becomes the rate determining step, and the ligand hydrogenation is completely suppressed in the case of [Co(dpnH)]⁺, but only partially in the case of [Co(dmgH)₂]. The rate of hydride formation in both cases is 2^nd order with respect to the complex, and the activation parameters ([Co(dmgH)₂]: ΔH^≠ = 48.4 ± 1.0 kJ · mol–¹, ΔS^≠ = ?57.4 ± 3.4J · mol^?1 · K^?1, [Co(dpnH)]⁺: ΔH^≠ = 52.7 = 0.4 kJ · mol^?1, ΔS^≠ = ?59.8 ± 1.2J · mol^?1 · K^?1) indicate a H₂-activation by homolytic splitting for both complexes. Some sources of error and possible causes for the missing activity of [Co(tim)]²⁺ are discussed.     

Kinetische Untersuchungen über Substitutionsreaktionen an Metallkomplexen. 11. Mitteilung [1]. Die Bildung von Tetrakis(triäthylphosphit)nickel(0) aus Nickelocen — eine Reaktion dritter Ordnung

Nickelocene Ni(π-C₅H₅)₂ reacts with triethylphosphite in dioxane at 50–70° to give Ni[P(OC₂H₅)₃]₄. Kinetic studies confirm a third-order rate law for this ligand substitution process with the activation parameters E_a = 6.8 kcal/mole and ΔS^≠ = ?53.8 e. u. The mechanistic implications of these results are discussed.     

Kinetic and Mechanistic Insights into the Pathway Leading to Cyclic Crystalline Phosphorus Ylide Formation in the Presence of 3‐Chloropentane‐2,4‐dione: Theoretical and Stopped‐Flow Approaches

In this work, three speculative mechanisms of the reaction between triphenylphosphine and dimethyl acetylendicarboxylate in the presence of 3‐chloropentane‐2,4‐dione were energetically and thermodynamically developed using quantum mechanical calculations and were profoundly compared with stopped‐flow and UV spectrophotometry approaches. The third speculative mechanism that led to the five‐membered ring structure was experimentally and theoretically favorable. The five‐membered ring structure of product was characterized by X‐ray crystallographic data. Also, steps 1 and 2 of the third mechanism were determined as fast and rate‐determining steps, respectively. The experimental kinetic evidence of the formation and decay of intermediate in steps 1 and 2 (fast and rate‐determining steps, respectively) was compatible with theoretical data. Experimental kinetic data were recognized for overall reaction along with activation parameters for fast and rate‐determining steps of the reaction. Theoretical kinetic data (k and E_a) and activation parameters (ΔG^≠, ΔS,^≠ and ΔH^≠) were calculated for each step and overall reactions.     

Spectroscopic and Electrochemical Studies of the Interaction of Some Gold(III) Complexes with Biologically Relevant Thiones

The interaction of gold(III) complexes, [Au(cis‐DACH)Cl₂]Cl and [Au(cis‐DACH)₂]Cl₃ complexes (DACH = cis‐1,2‐diaminocyclohexane), with ¹³C, ¹⁵N‐enriched thiourea (Tu) and 1,3‐diazinane‐2‐thione ligands was investigated. The progress of these reactions was monitored by NMR (¹H, ¹³C, and ¹⁵N) and UV–vis spectroscopy as well as square wave stripping voltammetry. The kinetic studies of the substitution reactions between the above‐mentioned complexes with thiones in aqueous solutions containing 30 mM KCl, which is used to suppress the hydrolysis of the chloride complexes, were conducted. These reactions were followed under pseudo–first‐order conditions as functions of ligand concentration, pH, and temperature. The activation parameters (ΔH^#, ΔS^#) were calculated from Eyring plots, and the negative values of ΔS^≠ lend support for an associative mechanism. The kinetic data also indicated a relatively higher reactivity of [Au(cis‐DACH)Cl₂]Cl than that of [Au(cis‐DACH)₂]Cl₃ toward the thiones.     

The kinetics and mechanism of the substitution reactions of the aquapentacyanoruthenate(II) ion with naphthalene‐substituted ligands in aqueous medium

The kinetics and mechanism of substitution reaction of [Ru(CN)₅H₂O]^3? anion with two naphthalene‐substituted ligands viz. Lⁿ = nitroso‐R‐salt (NRS) and α‐nitroso‐β‐naphthol (αNβN) have been studied spectrophotometrically by monitoring an increase in absorbance at λ_max = 525 nm corresponding to metal to ligand charge transfer (MLCT) transitions due to formation of substituted [Ru(CN)₅L]^n?3 as a function of pH, ionic strength, temperature, a wide range of ligands concentration, and [Ru(CN)₅H₂O^3?] under pseudo‐first‐order conditions. The experimental observation suggests that [Ru(CN)₅H₂O]^3? ion interacts with both ligands, which finally get converted into corresponding, [Ru(CN)₅L]^n?3 complexes as a final reaction product. The reaction is found to obey first‐order dependence each in [Ru(CN)₅H₂O^3?] and [Lⁿ]. The substituted products, viz. [Ru(CN)₅L]^n?3, in each case have strong MLCT transitions in visible region. The substitutional lability of [Ru(CN)₅H₂O]^3? has been discussed in terms of electronic effect on the M? OH₂ bond interactions. The kinetic observation suggests that the complexation reaction of [Ru(CN)₅H₂O]^3? with both the ligands, i.e., NRS and αNβN, follows an ion pair dissociative mechanism. The thermal activation parameters ΔH^≠ and ΔS^≠ have been calculated using Eyring's equation and provided in support for the proposed mechanistic scheme. © 2010 Wiley Periodicals, Inc. Int J Chem Kinet 43: 21–30, 2011     

A study of some reactions of acetylacetonatobis(ethylenediamine)cobalt(III) ion in sodium hydroxide solution

The reactions of acetylacetonato cobalt (III) ion in sodium hydroxide solutions have been studied spectrophotometrically over a range of temperatures and hydroxide ion concentrations. The activation enthalpy, ΔH^≠ was 70.6 kJ mol^?1 and the activation entropy, ΔS^≠ was ? 119 JK^?1mol^?1, with a rate law of k_obs = k₂ [OH^?]². A mechanism involving initial de-chelation of the acetylacetone ligand is suggested. The rate of exchange of methyl hydrogen of the acetylacetone ligand was studied, using proton nuclear magnetic resonance. The rate law was k_obs = k [OH^?]. Initial de-chelation is also suggested as a mechanism for this process. The ¹³C nuclear magnetic resonance spectrum of the complex is reported.     

Substitution of aqua ligands from cis‐[Pt(en)(H2O)2](ClO4)2 and cis‐[Pt(dmen)(H2O)2](ClO4)2 (en = ethylenediamine,dmen = N N′‐dimethyl ethylenediamine) by glycine in aqueous medium—a kinetic and mechanistic approach

The kinetics of the interaction of glycine with cis‐[Pt(en)(H₂O)₂](ClO₄)₂ and cis‐[Pt(dmen)(H₂O)₂](ClO₄)₂ (en = ethylenediamine, dmen = N,N′‐dimethylethylene‐diamine) have been studied spectrophotometrically as a function of [substrate complex], [glycine], and temperature at a particular pH (4.0) where the substrate complex exists predominantly as the diaqua species and glycine as the zwitterion. The reaction was found to proceed through two consecutive steps. The first step involves the ligand‐assisted anation, while the second step involves chelation when the second aqua ligand is displaced. Rate constants have been evaluated using the Weyh and Hamm method. Activation parameters for both steps have also been calculated using the Eyring equation. The low enthalpy of activation and large negative values of entropy of activation indicate an associative mode of activation for both steps. © 2005 Wiley Periodicals, Inc. Int J Chem Kinet 37: 489–495, 2005     

Mechanistic insights into photochromic behavior of a ruthenium(II)-pterin complex

The pterin‐coordinated ruthenium complex, [Ru^II(dmdmp)(tpa)]⁺ ( 1 ) (Hdmdmp=N,N‐dimethyl‐6,7‐dimethylpterin, tpa=tris(2‐pyridylmethyl)amine), undergoes photochromic isomerization efficiently. The isomeric complex ( 2 ) was fully characterized to reveal an apparent 180° pseudorotation of the pterin ligand. Photoirradiation to the solution of 1 in acetone with incident light at 460 nm resulted in dissociation of one pyridylmethyl arm of the tpa ligand from the Ru^II center to give an intermediate complex, [Ru(dmdmp)(tpa)(acetone)]²⁺ ( I ), accompanied by structural change and the coordination of a solvent molecule to occupy the vacant site. The quantum yield (?) of this photoreaction was determined to be 0.87 %. The subsequent thermal process from intermediate I affords an isomeric complex 2 , as a result of the rotation of the dmdmp^2? ligand and the recoordination of the pyridyl group through structural change. The thermal process obeyed first‐order kinetics, and the rate constant at 298 K was determined to be 5.83×10^?5 s^?1. The activation parameters were determined to be ΔH^≠=81.8 kJ mol^?1 and ΔS^≠=?49.8 J mol^?1 K^?1. The negative ΔS^≠ value indicates that this reaction involves a seven‐coordinate complex in the transition state (i.e., an interchange associative mechanism). The most unique point of this reaction is that the recoordination of the photodissociated pyridylmethyl group occurs only from the direction to give isomer 2 , without going back to starting complex 1 , and thus the reaction proceeds with 100 % conversion efficiency. Upon heating a solution of 2 in acetonitrile, isomer 2 turned back into starting complex 1 . The backward reaction is highly dependent on the solvent: isomer 2 is quite stable and hard to return to 1 in acetone; however, 2 was converted to 1 smoothly by heating in acetonitrile. The activation parameters for the first‐order process in acetonitrile were determined to be ΔH^≠=59.2 kJ mol^?1 and ΔS^≠=?147.4 kJ mol^?1 K^?1. The largely negative ΔS^≠ value suggests the involvement of a seven‐coordinate species with the strongly coordinated acetonitrile molecule in the transition state. Thus, the strength of the coordination of the solvent molecule to the Ru^II center is a determinant factor in the photoisomerization of the Ru^II–pterin complex.     

Synthesis and Diels-Alder Reactivity of 2,3,5,6-Tetramethylidenenorbornane

Pd-catalyzed double carbomethoxylation of the Diels-Alder adduct of cyclo-pentadiene and maleic anhydride yielded the methyl norbornane-2,3-endo-5, 6-exo-tetracarboxylate ( 4 ) which was transformed in three steps into 2,3,5,6-tetramethyl-idenenorbornane ( 1 ). The cycloaddition of tetracyanoethylene (TCNE) to 1 giving the corresponding monoadduct 7 was 364 times faster (toluene, 25°) than the addition of TCNE to 7 yielding the bis-adduct 9 . Similar reactivity trends were observed for the additions of TCNE to the less reactive 2,3,5,6-tetramethylidene-7-oxanorbornane ( 2 ). The following second order rate constants (toluene, 25°) and activation parameters were obtained for: 1 + TCNE → 7 : k₁ = (255 + 5) 10^?4 mol^?1 · s^?1, ΔH≠ = (12.2 ± 0.5) kcal/mol, ΔS≠ = (?24.8 ± 1.6) eu.; 7 + TCNE → 9 , k₂ = (0.7 ± 0.02) 10^?4 mol^?1 · s^?1, ΔH≠ = (14.1 ± 1.0) kcal/mol, ΔS≠ = ( ?30 ± 3.5) eu.; 2 + TCNE → 8 : k₁ = (1.5 ± 0.03) 10^?4 mol^?1 · s^?1, ΔH≠ = (14.8 ± 0.7) kcal/mol, ΔS≠ = (?26.4 ± 2.3) eu.; 8 + TCNE → 10 ; k₂ = (0.004 ± 0.0002) 10^?4 mol^?1 · s^?1, ΔH≠ = (17 ± 1.5) kcal/mol, ΔS≠ = (?30 ± 4) eu. The possible origins of the relatively large rate ratios k₁/k₂ are discussed briefly.     

Evidence for a Rapid Degenerate Hetero‐Cope‐Type Rearrangement in [Cp*W(S)2S‐CH2‐CHCH2]

Treatment of the salt [PPh₄]⁺[Cp*W(S)₃]^? ( 6 ) with allyl bromide gave the neutral complex [Cp*W(S)₂S‐CH₂‐CH?CH₂] ( 7 ). The product 7 was characterized by an X‐ray crystal structure analysis. Complex 7 features dynamic NMR spectra that indicate a rapid allyl automerization process. From the analysis of the temperature‐dependent NMR spectra a Gibbs activation energy of ΔG^≠ (278 K)≈13.7±0.1 kcal mol^?1 was obtained [ΔH^≠≈10.4±0.1 kcal mol^?1; ΔS^≠≈?11.4 cal mol^?1 K^?1]. The DFT calculation identified an energetically unfavorable four‐membered transition state of the “forbidden” reaction and a favorable six‐membered transition state of the “Cope‐type” allyl rearrangement process at this transition‐metal complex core.     

Mechanism of nucleophilic substitution in chromium(III) complexes. II. Formation of Acetatopentamminechromium(III)-ion from aquopentamminechromium(III)-ion in acetic acid — sodium acetate buffer media

The rate of formation of the acetatopentamminechromium(III)ion from the aquopentammine complex in HOAc? NaOAc buffer media has been investigated spectrophotometrically. The results suggest that the reaction occurs by two concurrent paths one of which is independent of acetate ion while the other is first order with respect to acetate ion concentration. The values of the rate constants for both the steps and the corresponding activation parameters, ΔH^≠ and ΔS^≠, have been evaluated. The results are consistent with an S_N1 mechanism for the acetate independent path and an S_N1 IP mechanism for the acetate dependent path. Evidence for ion-pair formation is given.     

Kinetics of Acid Blue 1 Adsorption from Aqueous Solution by Carbonaceous Substrate Produced from Biotic Precursor

Adsorption of acid blue 1 from aqueous solution onto carbonaceous substrate produced from the wood of Paulownia tomentosa was investigated. The samples characterized by FTIR, SEM, EDS and XRD techniques, indicated that the surface functional groups like carboxyl, lactones or phenols and ethers have disappeared at high activation temperature （800 ℃） and as a result porous structure was developed that has a positive effect on the adsorption capacity. Bangham and parabolic diffusion models were applied to the kinetic adsorption data, which show that the adsorption of acid blue 1 was a diffusion controlled process. The reaction rate increased with the increase in temperatures of both the adsorption and activation. Thermodynamic parameters like △E^≠, △H^≠, △S^≠ and △G^≠ were calculated from the kinetic data. The negative values of △S^≠ reflected the decrease in the disorder of the system at the solid-solution interface during adsorption. Gibbs free energy （△G^≠）, representing the driving force for the affinity of dye for the carbon surface, increased with the increase in sample activation and the adsorption temperatures.     

Bistable or Oscillating State Depending on Station and Temperature in Three‐Station Glycorotaxane Molecular Machines

High‐yield, straightforward synthesis of two‐ and three‐station [2]rotaxane molecular machines based on an anilinium, a triazolium, and a mono‐ or disubstituted pyridinium amide station is reported. In the case of the pH‐sensitive two‐station molecular machines, large‐amplitude movement of the macrocycle occurred. However, the presence of an intermediate third station led, after deprotonation of the anilinium station, and depending on the substitution of the pyridinium amide, either to exclusive localization of the macrocycle around the triazolium station or to oscillatory shuttling of the macrocycle between the triazolium and monosubstituted pyridinium amide station. Variable‐temperature ¹H NMR investigation of the oscillating system was performed in CD₂Cl₂. The exchange between the two stations proved to be fast on the NMR timescale for all considered temperatures (298–193 K). Interestingly, decreasing the temperature displaced the equilibrium between the two translational isomers until a unique location of the macrocycle around the monosubstituted pyridinium amide station was reached. Thermodynamic constants K were evaluated at each temperature: the thermodynamic parameters ΔH and ΔS were extracted from a Van′t Hoff plot, and provided the Gibbs energy ΔG. Arrhenius and Eyring plots afforded kinetic parameters, namely, energies of activation E_a, enthalpies of activation ΔH^≠, and entropies of activation ΔS^≠. The ΔG values deduced from kinetic parameters match very well with the ΔG values determined from thermodynamic parameters. In addition, whereas signal coalescence of pyridinium hydrogen atoms located next to the amide bond was observed at 205 K in the oscillating rotaxane and at 203 K in the two‐station rotaxane with a unique location of the macrocycle around the pyridinium amide, no separation of ¹H NMR signals of the considered hydrogen atoms was seen in the corresponding nonencapsulated thread. It is suggested that the macrocycle acts as a molecular brake for the rotation of the pyridinium–amide bond when it interacts by hydrogen bonding with both the amide NH and the pyridinium hydrogen atoms at the same time.