Dissection of Environmental Changes at the Cytoplasmic Surface of Light‐activated Bacteriorhodopsin and Visual Rhodopsin: Sequence of Spectrally Silent Steps†

The physico‐chemical properties as well as the conformation of the cytoplasmic surface of the 7‐helix retinal proteins bacteriorhodopsin (bR) and visual rhodopsin change upon light activation. A recent study found evidence for a transient softening of bR in its key intermediate M [Pieper et al. (2008) Phys. Rev. Lett. 100 , 228103] as a direct proof for the functional significance of protein flexibility. In this report we compare environmental and flexibility changes at the cytoplasmic surface of light‐activated bR and rhodopsin detected by time‐resolved fluorescence spectroscopy. The changes in fluorescence of covalently bound fluorescent probes and protein real‐time dynamics were investigated. We found that in fluorescently labeled bR and rhodopsin the intensity of fluorescein and Atto647 increased upon formation of the key intermediates M and metarhodopsin‐II, respectively, suggesting different surface properties compared to the dark state. Furthermore, time‐resolved fluorescence anisotropy experiments reveal an increase in steric restriction of loop flexibility because of changes in the surrounding protein environment in both the M‐intermediate as well as the active metarhodopsin‐II state. The kinetics of the fluorescence changes at the rhodopsin surface uncover multiple transitions, suggesting metarhodopsin‐II substates with different surface properties. Proton uptake from the aqueous bulk phase correlates with the first transition, while late proton release seems to parallel the second transition. The last transition between states of different surface properties correlates with metarhodopsin‐II decay.     

A Usual G‐Protein‐Coupled Receptor in Unusual Membranes

G‐protein‐coupled receptors (GPCRs) are the largest family of membrane‐bound receptors and constitute about 50 % of all known drug targets. They offer great potential for membrane protein nanotechnologies. We report here a charge‐interaction‐directed reconstitution mechanism that induces spontaneous insertion of bovine rhodopsin, the eukaryotic GPCR, into both lipid‐ and polymer‐based artificial membranes. We reveal a new allosteric mode of rhodopsin activation incurred by the non‐biological membranes: the cationic membrane drives a transition from the inactive MI to the activated MII state in the absence of high [H⁺] or negative spontaneous curvature. We attribute this activation to the attractive charge interaction between the membrane surface and the deprotonated Glu134 residue of the rhodopsin‐conserved ERY sequence motif that helps break the cytoplasmic “ionic lock”. This study unveils a novel design concept of non‐biological membranes to reconstitute and harness GPCR functions in synthetic systems.     

Retinal Conformation and Dynamics in Activation of Rhodopsin Illuminated by Solid‐state 2H NMR Spectroscopy†

Solid‐state NMR spectroscopy gives a powerful avenue for investigating G protein‐coupled receptors and other integral membrane proteins in a native‐like environment. This article reviews the use of solid‐state ²H NMR to study the retinal cofactor of rhodopsin in the dark state as well as the meta I and meta II photointermediates. Site‐specific ²H NMR labels have been introduced into three regions (methyl groups) of retinal that are crucially important for the photochemical function of rhodopsin. Despite its phenomenal stability ²H NMR spectroscopy indicates retinal undergoes rapid fluctuations within the protein binding cavity. The spectral lineshapes reveal the methyl groups spin rapidly about their three‐fold (C₃) axes with an order parameter for the off‐axial motion of For the dark state, the ²H NMR structure of 11‐cis‐retinal manifests torsional twisting of both the polyene chain and the β‐ionone ring due to steric interactions of the ligand and the protein. Retinal is accommodated within the rhodopsin binding pocket with a negative pretwist about the C11=C12 double bond. Conformational distortion explains its rapid photochemistry and reveals the trajectory of the 11‐cis to trans isomerization. In addition, ²H NMR has been applied to study the retinylidene dynamics in the dark and light‐activated states. Upon isomerization there are drastic changes in the mobility of all three methyl groups. The relaxation data support an activation mechanism whereby the β‐ionone ring of retinal stays in nearly the same environment, without a large displacement of the ligand. Interactions of the β‐ionone ring and the retinylidene Schiff base with the protein transmit the force of the retinal isomerization. Solid‐state ²H NMR thus provides information about the flow of energy that triggers changes in hydrogen‐bonding networks and helix movements in the activation mechanism of the photoreceptor.     

Binding of Copper(II) to Pectins by Electrochemical Methods

The interaction between Cu(II) and pectin extracted from citrus fruit was studied in KNO₃ 0.10 mol dm^?3 at 25 °C and pH 5.5, using ion selective electrode potentiometry and voltammetry, namely differential pulse polarography and square‐wave voltammetry. Although many independent variables may affect Cu(II)‐polymer interactions such as charge density, polymer concentration and copper to polymer concentration ratio, a good fitting was observed for the model with ML and ML₂ complex species, when M:L total concentration (mol dm^?3) ratio varies from 0.2 to 2.7 and the ligand concentration is in the range (0.2 to 1) g dm^?3, i.e., (0.4 to 2)×10^?3 mol COO^? dm^?3. The complex parameters found in these conditions were log β_CuL=3.5±0.1 and log β_CuL2= 8.0±0.2. For lower total ligand and total metal ion concentrations, used in voltammetry, the interaction Cu(II)‐pectin is affected by a cooperative mode (increase of metal ion‐ligand affinity) when the total metal ion concentration increases and by an anti‐cooperative mode when the total ligand concentration increases, possibly due to different conformations of the polymer.     

Transducin activation by molecular species of rhodopsin other than metarhodopsin II

Decay of metarhodopsin II was accelerated by hydroxylamine treatment or dark incubation of metarhodopsin II at 30 degrees C. The products thus obtained after decay of metarhodopsin II induced GTPase activity on transducin as well as metarhodopsin II suggesting that rhodopsin could activate transducin after the decay of metarhodopsin II intermediate. After urea-treated bovine rod outer segment membrane was completely bleached, rhodopsin in the membrane was regenerated by the addition of 11-cis retinal at various temperatures between 0 and 37 degrees C. The capacity to induce GTPase activity on transducin and phosphate incorporating capacity catalyzed by rhodopsin kinase were measured on such rhodopsins. The results showed that: (1) Regeneration of alpha band of rhodopsin was complete regardless of regeneration temperature; (2) When regenerated at temperatures below 10 degrees C, rhodopsins induced a GTPase activity on transducin in the dark even after treatment with hydroxylamine, whereas rhodopsins after regeneration at temperatures above 13 degrees C did not; (3) When regenerated at 0 degrees C, rhodopsin was phosphorylated if incubated with rhodopsin kinase and ATP in the dark, whereas the spectrally regenerated rhodopsin at 30 degrees C was not. The complete quenching of functions of photoactivated rhodopsin was achieved by recombination with 11-cis retinal at temperatures above 13 degrees C but not below 10 degrees C suggesting the existence of a low temperature intermediate upon regeneration.     

Influence of Arrestin on the Photodecay of Bovine Rhodopsin

Continued activation of the photocycle of the dim‐light receptor rhodopsin leads to the accumulation of all‐trans‐retinal in the rod outer segments (ROS). This accumulation can damage the photoreceptor cell. For retinal homeostasis, deactivation processes are initiated in which the release of retinal is delayed. One of these processes involves the binding of arrestin to rhodopsin. Here, the interaction of pre‐activated truncated bovine visual arrestin (Arr^Tr) with rhodopsin in 1,2‐diheptanoyl‐sn‐glycero‐3‐phosphocholine (DHPC) micelles is investigated by solution NMR techniques and flash photolysis spectroscopy. Our results show that formation of the rhodopsin–arrestin complex markedly influences partitioning in the decay kinetics of rhodopsin, which involves the simultaneous formation of a meta II and a meta III state from the meta I state. Binding of Arr^Tr leads to an increase in the population of the meta III state and consequently to an approximately twofold slower release of all‐trans‐retinal from rhodopsin.     

A COMPARISON OF LIGHT-TRIGGERED SPECTRAL CHANGES IN RHODOPSIN AND ISORHODOPSIN

Abstract— This report describes spectral changes associated with the transformation of metarhodopsin I to metarhodopsin II following light excitation of isorhodopsin and rhodopsin. Irradiated isorhodopsin gives rise to an equilibrium mixture of metarhodopsin I and metarhodopsin II which at 2°C and pH 6.8 favors the former. Isorhodopsin and rhodopsin are converted to metarhodopsin II via metarhodopsin I at very similar rates and activation parameters for the conversions are essentially identical. It is concluded that the initial cis to trans isomerization erases all differences in the two pigments.     

A Promising Candidate with D‐A‐A‐A Architecture as an Efficient Sensitizer for Dye‐Sensitized Solar Cells

A series of metal‐free organic dyes with electron‐rich (D) and electron‐deficient units (A) as π linkers have been studied theoretically by means of density functional theory (DFT) and time‐dependent DFT calculations to explore the effects of π spacers on the optical and electronic properties of triphenylamine dyes. The results show that Dye 1 with a structure of D‐A‐A‐A is superior to the typical C218 dye in various key aspects, including the maximum absorption (λ_max=511 nm), the charge‐transfer characteristics (D/Δq/t is 5.49 Å/0.818 e^?/4.41 Å), the driving force for charge‐carrier injection (ΔG_inject=1.35 eV)/dye regeneration (ΔG_regen=0.27 eV), and the lifetime of the first excited state (τ=3.1 ns). It is thus proposed to be a promising candidate in dye‐sensitized solar cell applications.     

Water‐Exchange Mechanism for Zinc(II), Cadmium(II), and Mercury(II) Ions in Water as Studied by Umbrella‐Sampling Molecular‐Dynamics Simulations

Umbrella‐sampling molecular‐dynamics simulations were performed to investigate the water‐exchange reactions of zinc(II), cadmium(II), and mercury(II) ions in aqueous solution. The dissociation of a coordinating water molecule to the M? O distance at 3.34, 3.16, and 3.26 Å for Zn^II, Cd^II, and Hg^II, respectively, leads the system to a transition state. For Zn^II, the first hydration shell is occupied by five spectator water molecules in the transition state, indicating that the water‐exchange reaction proceeds via a dissociative mode of activation. In contrast, the number of spectator water molecules of 5.85 and 5.95 for Cd^II and Hg^II, respectively, suggests an associative exchange for these larger metal ions. The average M? O distance of the spectator molecules is shortened by 0.06 Å for the dissociative exchange of Zn^II, while it is elongated by 0.04 and 0.03 Å for Cd^II and Hg^II, respectively. The water‐exchange rate constants of 4.1×10⁸, 6.8×10⁸, and 1.8×10⁹ s^?1 are estimated for Zn^II, Cd^II, and Hg^II, respectively, at 298 K in terms of the transition‐state theory based on the assumption of a transmission coefficient of unity.     

Synthesis,Band and Crystal Structures,and Optical Properties of the Ternary Compound Mg2Te3O8

The new spiroffite Mg₂Te₃O₈ ( 1 ) was prepared by hydrothemal methods and structurally characterized by single‐crystal X‐ray diffraction analysis. Compound 1 crystallizes in the space group C2/c of the monoclinic system with two formula units in a cell: a = 12.6030(7), b = 5.2254(3), c = 11.6331(7) Å, β = 98.6960(10)°, V = 757.30(8) ų. The structure features a 3D open‐framework with spiroffite topology that has large tunnels approximately 3.2 × 5.5 Å. The optical properties and thermal stability of 1 were characterized by UV and IR spectroscopy as well as TG. Calculations of the electronic band structure along with the density of states (DOS) indicate that the present compound is a semiconductor with an indirect band gap, and that the optical absorption is mainly originated from the charge transitions from O‐2p state to Te‐5p and Te‐5s states.     

Activity switches of rhodopsin

Rhodopsin, the visual pigment of the rod photoreceptor cell contains as its light-sensitive cofactor 11-cis retinal, which is bound by a protonated Schiff base between its aldehyde group and the Lys296 side chain of the apoprotein. Light activation is achieved by 11-cis to all-trans isomerization and subsequent thermal relaxation into the active, G protein-binding metarhodopsin II state. Metarhodopsin II decays via two parallel pathways, which both involve hydrolysis of the Schiff base eventually to opsin and released all-trans retinal. Subsequently, rhodopsin's dark state is regenerated by a complicated retinal metabolism, termed the retinoid cycle. Unlike other retinal proteins, such as bacteriorhodopsin, this regeneration cycle cannot be short cut by light, because blue illumination of active metarhodopsin II does not lead back to the ground state but to the formation of largely inactive metarhodopsin III. In this review, mechanistic details of activating and deactivating pathways of rhodopsin, particularly concerning the roles of the retinal, are compared. Based on static and time-resolved UV/Vis and FTIR spectroscopic data, we discuss a model of the light-induced deactivation. We describe properties and photoreactions of metarhodopsin III and suggest potential roles of this intermediate for vision.     

THE CRYSTAL,MOLECULAR STRUCTURE AND LIGAND BONDING IN TETRAKIS (N,N′-DIMETHYLTHIOUREA) NICKEL (II) BROMIDE DIHYDRATE

Abstract

The crystal structure of tetrakis(N,N′-dimethylthiourea)nickel(II) bromide dihydrate has been determined by three-dimensional x-ray diffraction from 1916 counter-data reflections collected at room temperature.

The structure consists of Ni[SC(NH)₂(CH₃)₂]²⁺ ₄ molecular ions, Br^? ions and waters of hydration. The nickel is located on a center of symmetry and is coordinated to four sulfur atoms in a square planar configuration. The waters of hydration and the bromide ions are involved in hydrogen bonding to the N,N′-dimethylthiourea (dmtu) groups. The orientation of the dmtu groups is such that two bond through the sulfur sp² orbital and the others bond through the π-orbitals of the dmtu group. The Ni-S distances are 2.204 ± 0.002 Å and 2.230 ± 0.002 Å, and the Ni-S-C angles are 106.2 ± 0.2Å and 110.3 ± 0.3°. The dmtu groups are planar except for methyl hydrogens.

The crystals are monoclinic, P2₁/a with a = 13.424 ± 0.002 Å, b = 12.321 ± 0.005 Å, c = 8.460 ± 0.008 Å β = 107.07 ± 0.05°, ρ₀ = 1.67 g cm^?3, ρ_c = 1.66 g cm^?3 and Z = 2. The structure was refined by full-matrix least-squares to a conventional R of 0.0466.     

A Crystallographic Charge Density Study of the Partial Covalent Nature of Strong N⋅⋅⋅Br Halogen Bonds

The covalent nature of strong N?Br???N halogen bonds in a cocrystal ( 2 ) of N‐bromosuccinimide ( NBS ) with 3,5‐dimethylpyridine ( lut ) was determined from X‐ray charge density studies and compared to a weak N?Br???O halogen bond in pure crystalline NBS ( 1 ) and a covalent bond in bis(3‐methylpyridine)bromonium cation (in its perchlorate salt ( 3 ). In 2 , the donor N?Br bond is elongated by 0.0954 Å, while the Br???acceptor distance of 2.3194(4) is 1.08 Å shorter than the sum of the van der Waals radii. A maximum electron density of 0.38 e Å^?3 along the Br???N halogen bond indicates a considerable covalent contribution to the total interaction. This value is intermediate to 0.067 e Å^?3 for the Br???O contact in 1 , and approximately 0.7 e Å^?3 in both N?Br bonds of the bromonium cation in 3 . A calculation of the natural bond order charges of the contact atoms, and the σ*(N1?Br) population of NBS as a function of distance between NBS and lut , have shown that charge transfer becomes significant at a Br???N distance below about 3 Å.     

A Novel Fluorescent Aminoacid Designed for Fluorometric Detection of Cu （Ⅱ）

A fluorescent aminoacid was designed for selective and sensitive detection of Cu(II) in aqueous solution. The designing of this Cu(II) fluorescent chemosensing molecule, N ± (1‐naphthyl). aminoacetic acid (NAA), was based on the binding of Cu(II) to aminoacetic acid and the novel charge transfer photophysics of 1‐aminonaphthalenes. The fluorescence of NAA was found quenched by Cu (II) and several other metal ions of similar electronic structure such as Co(II), Ni(II) and Zn(II). The quenching was shown to occur via electron transfer within the metal‐NAA complex, which required an optimal combination of high binding affinity and favorable redox properties of the components in the metal‐NAA complex and hence afforded selective fluorometric detection of Cu(II). The calibration graph obeyed Stern‐Volmer theory and was shown for Cu(II) over the range of 0–2.75 ± 10–⁴ mol/L. The quenching constant of Cu(II) was measured as 8.0 ± 10³ mol/L that was two orders of magnitude higher than those of Co(II), Ni(II) and Zn(II). The 3SD limit of detection for Cu(II) was 8.00 ± 10^?6 mol/L with a coefficient of variation of 1.65%. Linear range for quantitative detection of Cu(II) was 2.67 ± 10^?5‐2.75 ± 10^?4 mol/L. The method was applied to synthetic sample measurements which gave recoveries of 105%‐112%.     

Structure and electrical conductivity of La0.84Sr0.16MnO3

X-Ray diffraction, density, and electrical conductivity measurements were performed on the perovskite-like mixed oxide La_0.84Sr_0.16MnO₃. A rhombohedral crystalline structure with lattice parameters a = 3.893 Å and α = 90°29′16″ was assigned to the powder prepared by standard ceramic technique. Its theoretical density is therefore 6.576 g/cm³, while the experimental density was determined as 6.48 g/cm³. The conductivity measured at 1000°C is 133 Ω^?1 cm^?1. The temperature dependence of the conductivity indicates that the charge carriers are small polarons. The activation energy of the mobility is 9.6 kJ/mole.     

Fehlordnung bei Smectiten in Abhängigkeit vom Zwischenschichtkation

Disorder in Smectites in Dependence of the Interlayer Cation Fluorosmectites, [M_0.5]^inter[Mg_2.5Li_0.5]^oct[Si₄]^tetO₁₀F₂ (M = Na, K, Rb, Cs), have been synthesised from the melt in gastight Mo crucibles. At the same layer charge of x = 0.5, which lies within the range of smectites, both, the crystallite size and the stacking order increases with the size of the interlayer cation. For microcrystalline Na‐hectorite both rotational (n120° and n60°) and translational (±0.145b) planar defects were identified, whereas for K‐hectorite only ±^b/₃ translational defects were found. Finally, Rb‐ and Cs‐hectorite show a normal Bragg‐type diffraction pattern. For Cs‐hectorite even single crystals may be found that display no diffuse scattering and allow a structure refinement (monoclinic, 1M‐polytype, C2/m, a = 5.2401(10)Å, b = 9.0942(10) Å, c = 10.7971(10)Å, β = 99.21 (2)°, V = 507.90(12) ų, Z = 2). These 3D ordered smectites still show satisfactory intracrystalline reactivity and the interlayer cations may readily be exchanged for organocations.     

The Glucocorticoid Receptor of the Neural Retina of the Chick Embryo: Gradual Changes in Charge of the Glucocorticoid Receptor Complex During Transformation,Detected by Electrofocusing

Abstract

Two main difficulties impede the monitoring of the changes in the surface charge of the triamcinolone acetonide-glucocorticoid-receptor (TA-GR) complex concomitant with GR-transformation by electrofocusing (EF). One difficulty relates to the high sensitivity of the nonactivated [³H]TA-GR complex to temperature. The second difficulty relates to the transforming effects of basic carrier ampholytes, pI′ range 8-10 (basic SCAMs) on GR. Performing EF at strictly controlled cold temperature, and omitting the use of basic SCAMS revealed that the nontransformed molybdate-stabilized TA-GR complexes in the cytosol of the neural retina consist of a homogeneously charged GR population exhibiting an apparent pI′ (pI) value of 5.0 ± 0.2 (contrary to the previously reported heterogeneity of GR in ‘nonactivated’ state¹). Exposure of the [³H]TA-GR to activation by physiological temperatures, or to activation by 0.4M KC1 in the cold, (in the presence of PMSF, which inhibits proteolytic degradation of GR in the neural retina²) transformed the acidic nonactivated GR complex (designated TA-GR I) to more basic GR species: TA-GR II with a pI′ of 5.6 ± 0.2 and TA-GR III with a pI′ of 6.2 ± 0.1. TA-GR II appeared as a minor component, and TA-GR III appeared as the major form in the activated state. Molybdate inhibited the formation of TA-GR III induced by 0.4M KC1, while it augmented TA-GR II. The formation of TA-GR II from molybdate-stabilized TA-GR I was enhanced by cytosol dilution. The increase in the amount of TA-GR II in molybdate-stabilized cytosol correlated with the decrease in the amount of TA-GR I and the absence of III, suggesting that TA-GR II represents an intermediate state of GR transformation. The suppression of TA-GR III by molybdate is reversible at 30°C. Inhibitors of proteases, leupeptin, antipain and PMSF, caused a slight decrease in the pI′ value of TA-GR II found in the activated cytosol, (5.4 instead of 5.7), but did not change the heterogeneity of GR species found in the activated state. The omission of basic SCAMs in this study reduced the previously reported pI′ values¹ of TA-GR species which had been artifactually increased by basic SCAMs. The pI′ values reported in this study were confirmed by replacing SCAMs with simple buffers as carrier constituents, and appear to reflect the authentic surface net charge of TA-GR. EF analysis of [³H]TA-GR complexes that were formed in the intact tissue at 0°C (cell-bound [³H]TA-GR) confirmed the charge homogeneity of the nonactivated GR complexes in the nonactivated cytosol but showed that the cell-bound nonactivated [³H]TA-GR is more acidic than the TA-GR I formed under cell-free conditions, exhibiting a pI′ value of 4.2 ± 0.1. These results are consistent with the hypothesis that GR transformation is a multistage process characterized by a progressive decrease in the negative net charge of the GR complex. The nature of the changes in negative net charge is discussed elsewhere² in relation to the changes in size of the GR complex occurring in the process of GR transformation.     

Probing the weakest bond and the cleavage of p‐chlorobenzaldehyde diperoxide energetic molecule via quantum chemical calculations and theoretical charge density analysis

A high‐level ab initio Hartree‐Fock/Møller‐Plesset 2 and density functional theory quantum chemical calculations were performed on p‐chlorobenzaldehyde diperoxide energetic molecule to understand its bond topological, electrostatic, and energetic properties. The optimized molecular geometry for the basis set 6‐311G** exhibit chair diperoxide ring and planar aromatic side rings. Although the diperoxide ring bear same type of side rings, surprisingly, both the rings are almost perpendicular to each other, and the dihedral angle is 96.1°. The MP2 method predicts the O? O bond distance as ～1.466 Å. The charge density calculation reveals that the C? C bonds of chlorobenzaldehyde ring have rich electron density and the value is ～2.14 e Å^?3. The maximum electron density of the O? O bonds does not lie along the internuclear axes; in view of this, a feeble density is noticed in the ring plane. The high negative values of laplacian of C? C bonds (approximately ?22.4 e Å^?5) indicate the solidarity of these bonds, whereas it is found too small (approximately ?1.8 e Å^?5 for MP2 calculation) in O? O bonds that shows the existence of high degree of bond charge depletion. The energy density in all the C? C bonds are found to be uniform. A high electronegative potential region is found at the diperoxide ring which is expected to be a nucleophilic attack area. Among the bonds, the O? O bond charge is highly depleted and it also has high bond kinetic energy density; in consequence of this, the molecular cleavage is expected to happen across these bonds when the material expose to any external stimuli such as heat or pressure treatment. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011     

The classical molecular dynamics simulation of graphene on Ru(0001) using a fitted Tersoff interface potential

The accurate molecular dynamics simulation of weakly bound adhesive complexes, such as supported graphene (gr), is challenging because of the lack of an adequate interface potential. Instead of the widely used Lennard‐Jones potential for weak and long‐range interactions, we use a newly parameterized Tersoff potential for gr/Ru(0001) system. The new interfacial force field provides adequate moire superstructures in accordance with scanning tunneling microscopy images and with density functional theory (DFT) results. In particular, the corrugation of ξ ≈ 1.0 ± 0.2 Å is found that is somewhat smaller than found by DFT approaches (ξ ≈ 1.2 Å) and is close to scanning tunneling microscope measurements (ξ ≈ 0.8 ± 0.3 Å). The new potential could open the way toward large‐scale simulations of supported gr with adequate moire supercells in many fields of gr research. Moreover, the new interface potential might provide a new strategy in general for obtaining accurate interaction potentials for weakly bound adhesion in large‐scale systems in which atomic dynamics is inaccessible yet by accurate DFT calculations. Copyright © 2013 John Wiley & Sons, Ltd.     

Thermochemistry and Kinetics of the Thermal Decomposition of 1‐Chlorohexane

A theoretical kinetic study of the thermal decomposition of 1‐chlorohexane in gas phase between 600 and 1000 K was performed. Transition‐state theory and unimolecular reaction rate theory were combined with molecular information provided by quantum chemical calculations. Particularly, the B3LYP, BMK, M05–2X, and M06–2X formulations of the density functional theory (DFT) and the high‐level ab initio methods G3B3 and G4 were employed. The possible reaction channels for the thermal decomposition of 1‐chlorohexane were investigated, and the reaction takes place through the elimination of HCl with the formation of 1‐hexene. The derived high‐pressure limit rate coefficients are k _∞(600–1000 K) = (8 ± 5) × 10¹³ exp[‐((56.7 ± 0.4) kcal mol⁻¹/RT )] s⁻¹. The pressure effect over the reaction was analyzed from the calculation of the low‐pressure limit rate coefficients and the falloff curves. In addition, the standard enthalpies of formation at 298 K of −46.9 ± 1.5 kcal mol⁻¹ for 1‐chlorohexane and 5.8 ± 1.5 kcal mol⁻¹ for C₆H₁₃ radical were derived from isodesmic and isogiric reactions at high levels of theory.