Structure,synthesis, and voltammetric investigation of 1-(quinolin-2-yl)-2-(pyran-2-yl)ethane-1,2-dione derivatives

By the XRD analysis the structure was established of 1-(7,8-dimethyl-4-chloroquinolin-2-yl)-2-[3,5-di(tert-butyl)-6-oxo-6H-pyran-2-yl]ethane-1,2-dione formed as a result of the oxidation of 3,5-di(tert-butyl)-6-[(Z)-2-(quinolin-2-yl)-1-hydroxyethen-1-yl]pyran-2-ones. By the cyclic voltammetry the oxidation of 1-(quinolin-2-yl)-2-(pyran-2-yl)ethane-1,2-dione derivatives was shown to proceed in two stages.     

Theoretical prediction of Ni(I)-catalyst for hydrosilylation of pyridine and quinoline

Catalytic synthesis of dihydropyridine by transition-metal complex is one of the important research targets, recently. Density functional theory calculations here demonstrate that nickel(I) hydride complex (bpy)Ni^IH (bpy = 2,2′-bipyridine) 1 is a good catalyst for hydrosilylation of both quinoline and pyridine. Two pathways are possible; in path 1, substrate reacts with 1 to form stable intermediate Int1 . After that, N³─C¹ bond of substrate inserts into Ni─H bond of 1 via TS1 to afford N-coordinated 1,2-dihydroquinoline Int2 with the Gibbs activation energy (ΔG°^‡) of 21.8 kcal mol⁻¹. Then, Int2 reacts with hydrosilane to form hydrosilane σ-complex Int3 ; this is named path 1A. In the other route (path 1B), Int1 reacts with phenylsilane in a concerted manner via hydride-shuttle transition state TS2 to afford Int3 . In TS2 , Si atom takes hypervalent trigonal bipyramidal structure. Formation of hypervalent structure is crucial for stabilization of TS2 (ΔG°^‡ = 17.3 kcal mol⁻¹). The final step of path 1 is metathesis between Ni─N³ bond of Int3 and Si─H bond of PhSiH₃ to afford N-silylated 1,2-dihydroproduct and regenerate 1 (ΔG°^‡ = 4.5 kcal mol⁻¹). In path 2, 1 reacts with hydrosilane to form Int5 , which then forms adduct Int6 with substrate through Si–N interaction between substrate and PhSiH₃. Then, N-silylated 1,2-dihydroproduct is produced via hydride-shuttle transition state TS5 (ΔG°^‡ = 18.8 kcal mol⁻¹). The absence of N-coordination of substrate to Ni^I in TS5 is the reason why path 2 is less favorable than path 1B. Quinoline hydrosilylation occurs more easily than pyridine because quinoline has the lowest unoccupied molecular orbital at lower energy than that of pyridine. © 2019 Wiley Periodicals, Inc.     

Theoretical and experimental studies of the diketene system: Product branching decomposition rate constants and energetics of isomers

The kinetics and mechanism for the thermal decomposition of diketene have been studied in the temperature range 510–603 K using highly diluted mixtures with Ar as a diluent. The concentrations of diketene, ketene, and CO₂ were measured by FTIR spectrometry using calibrated standard mixtures. Two reaction channels were identified. The rate constants for the formation of ketene (k₁) and CO₂ (k₂) have been determined and compared with the values predicted by the Rice–Ramsperger–Kassel–Marcus (RRKM) theory for the branching reaction. The first-order rate constants, k₁ (s⁻¹) = 10^{15.74 ± 0.72} exp(−49.29 (kcal mol⁻¹) (±1.84)/RT) and k₂ (s⁻¹) = 10^{14.65 ± 0.87} exp(−49.01 (kcal mol⁻¹) (±2.22)/RT); the bulk of experimental data agree well with predicted results. The heats of formation of ketene, diketene, cyclobuta-1,3-dione, and cyclobuta-1,2-dione at 298 K computed from the G2M scheme are −11.1, −45.3, −43.6, and −40.3 kcal mol⁻¹, respectively. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 580–590, 2007     

Synthesis and Characterization of Novel Chiral (1R,2R)-1,2-Bis[5-(Aminomethylphospinic Acid)-1,3,4-Thiadiazol-2-YL]Ethane-1,2-Diols

Abstract

(1R,2R)-1,2-bis[5-(arylideneamino)-1,3,4-thiadiazol-2-yl]ethane-1,2-diol (2a–d) were synthesized by using appropriate aldehydes and (1R,2R)-1,2-bis(5-amino-1,3,4-thiadiazol-2-yl)ethane-1,2-diol (1) as a starting compound. Then, the phosphinic acid component (3a–d) were obtained from (2a–d) and hypophosporus acid. In addition, the structures of the novel chiral compounds (2a–d) and (3a–d) were confirmed by elemental analyses, IR, ¹H-NMR, ¹³C-NMR, and ³¹P-NMR spectra.

¹H NMR and ¹³C NMR spectra for 1, 2a, and 3a (Figures S1–S6) are available online in the Supplemental Materials.     

The Dewar Isomer of 1,2‐Dihydro‐1,2‐azaborinines: Isolation,Fragmentation, and Energy Storage

The photochemistry of 1,2‐dihydro‐1,2‐azaborinine derivatives was studied under matrix isolation conditions and in solution. Photoisomerization occurs exclusively to the Dewar valence isomers upon irradiation with UV light (>280 nm) with high quantum yield (46 %). Further photolysis with UV light (254 nm) results in the formation of cyclobutadiene and an iminoborane derivative. The thermal electrocyclic ring‐opening reaction of the Dewar valence isomer back to the 1,2‐dihydro‐1‐tert‐butyldimethylsilyl‐2‐mesityl‐1,2‐azaborinine has an activation barrier of (27.0±1.2) kcal mol⁻¹. In the presence of the Wilkinson catalyst, the ring opening occurs rapidly and exothermically (ΔH=(−48±1) kcal mol⁻¹) at room temperature.     

The mechanism of fluxionality of (1,2,7-η3-2-Me-benzyl)(η5-C5H5)Mo(CO)2

It is shown that (1,2,7-η³-2-Me-benzyl)(η⁵-C₅H₅)Mo(CO)₂ exits in solution as one isomer which is fluxional, probably via (7-η¹-2-Me-benzyl)((η⁵-C₅H₅)Mo(CO)₂, with ΔG^≠₃₇₀ = 23.6 ± 1.0 kcal mol⁻¹. In contrast, (1,2,7-η³-3-Me-benzyl)(η⁵-C₅H₅)Mo(CO)₂ exits as two isomers at −20°C, which undergo interconversion at room temperature with ΔG^≠ 15.7 kcal mol⁻¹. This dynamic process is an allyl rotation. It is probable that there is also a low energy [1,5]-sigmatropic shift.     

Enthalpy and entropy of activation and the heat effect of the ene reaction between 4-phenyl-1,2,4-triazoline-3,5-dione and 2,3-dimethyl-2-butene in solution

The rate of the fastest ene reaction between 4-phenyl-1,2,4-triazoline-3,5-dione (1) and 2,3-dimethyl-2-butene (2) is studied by means of stopped flow in solutions of benzene (k ₂ = 55.6 ± 0.5 and 90.5 ± 1.3 L mol^?1 s^?1 at 23.3 and 40°C) and 1,2-dichloroethane (335 ± 9 L mol^?1 s^?1 at 23.5°C). The enthalpy of reaction (?139.2 ± 0.6 kJ/mol in toluene and ?150.2 ± 1.4 kJ/mol in 1,2-dichloroethane) and the enthalpy (20.0 ± 0.5 kJ/mol) and entropy (144 ± 2 J mol^?1 K^?1) of activation are determined. A clear correlation is observed between the reaction rate and ionization potential in a series of ene reactions of 4-phenyl-1,2,4-tri-azoline-3,5-dione with acyclic alkenes.     

Reactivity of bis(pyrazol-1-yl)methanes functionalized by 2-hydroxyphenyl and 2-methoxyphenyl on the methine carbon atom with W(CO)5THF

Reactions of 2-hydroxyphenyl and 2-methoxyphenylbis(pyrazol-1-yl)methanes as well as 2-hydroxyphenyl and 2-methoxyphenylbis(3,5-dimethylpyrazol-1-yl)methanes with W(CO)₅THF have been carried out. Heating 2-hydroxyphenylbis(pyrazol-1-yl)methane (L¹) with W(CO)₅THF in THF at reflux yielded complex (L¹)W(CO)₄.L¹, while similar reaction of 2-hydroxyphenylbis(3,5-dimethylpyrazol-1-yl)methane (L²) with W(CO)₅THF resulted in the cleavage of a C_sp3-N bond to generate 1,2-bis(2-hydroxyphenyl)-1,2-bis(3,5-dimethylpyrazol-1-yl)ethane (L) and pyrazole derivative W(CO)₅(3,5-Me₂PzH) (Pz = pyrazol-1-yl). These two fragments were connected together through strong O…H-N and O-H…N hydrogen bonds to form complex L.[W(CO)₅(3,5-Me₂PzH)]₂. The analogous results were observed in the treatment of 2-methoxyphenylbis(pyrazol-1-yl)methane (L³) with W(CO)₅THF, which gave product L′.[W(CO)₅(PzH)]₂ (L′ = 1,2-bis(2-methoxyphenyl)-1,2-bis(pyrazol-1-yl)ethane) as well as certain amount of complex (L³)W(CO)₄. In addition, during the reaction of 2-methoxyphenylbis(3,5-dimethylpyrazol-1-yl)methane (L⁴) with W(CO)₅THF, partial decomposition reactions took place to yield complexes (L⁴)W(CO)₄ and W(CO)₅(3,5-Me₂PzH), but no hydrogen bond was found between these two moieties.     

Thermodynamic properties of potassium metasilicate (K2SiO3)

The standard enthalpy of formation of potassium metasilicate (K₂SiO₃), determined by hydrofluoric acid solution calorimetry, was found to be ΔH^o_f,298 = −363.866±0.421 kcal mol⁻¹ (−1522.415±1.762 kj mol⁻¹). The standard enthalpy of formation from the oxides was found to beΔH^o₂₉₈ = −64.786±0.559 kcal mol⁻¹ (−271.065±2.339 kJ mol⁻¹).These experimentally determined data were combined with data from the literature to calculate the Gibbs energies of formation and equilibrium constants of formation over the temperature range of the literature data. The standard enthalpies of formation and Gibbs energies of formation are given as functions of temperature. The standard Gibbs energy of formation is ΔG_f,298.15⁰ = −341.705 kcal mol⁻¹ (−1429.694 kJ mol⁻¹).     

Far-infrared spectra and barriers to internal rotation of ethyl nitrate

The far-infrared spectra of gaseous and solid ethyl nitrate, CH₃CH₂ONO₂, have been recorded from 500 to 50 cm⁻¹. The fundamental asymmetric torsion of the trans conformer which has a heavy atom plane has been observed at 112.50 cm⁻¹ with two excited states failing to lower frequencies, and the corresponding fundamental torsion of the gauche conformer was observed at 109.62 cm⁻¹ with two excited states also falling to lower frequencies. The results of a variable temperature Raman study indicate that the trans conformer is more stable than the gauche conformer by 328 ± 96 cm⁻¹ (938 ± 275 cal mol⁻¹). An asymmetric potential function governing the internal rotation about the CH₂O bond is reported which gives a trans to gauche barrier of 894 ± 15 cm⁻¹ (2.56 ± 0.04 kcal mol⁻¹) and a gauche to gauche barrier of 3063 ± 68 cm⁻¹ (8.76 ± 0.20 kcal mol⁻¹) with the trans conformer more stable by 220 ± 148 cm⁻¹ (0.63 ± 0.42 kcal mol⁻¹). Transitions arising from the symmetric CH₃ and NO₂ torsions are observed for both conformers, from which the threefold and twofold periodic barriers to internal rotation have been calculated. For the trans conformer the values are 1002 cm⁻¹ (2.87 kcal mol⁻¹) and 2355 ± 145 cm⁻¹ (6.73 ± 0.42 kcal mol⁻¹) and for the gauche conformer they are 981 cm⁻¹ (2.81 kcal mol⁻¹) and 2736 ± 632 cm⁻¹ (7.82 ± 1.81 kcal mol⁻¹) for the CH₃ and NO₂ rotors, respectively. These results are compared to the corresponding quantities for some similar molecules.     

Synthesis and kinetics of polymerization of acrylic and methacrylic monomers containing 1,3-dioxane groups in their structure

(5-Ethyl-1,3-dioxane-5-yl) methyl acrylate (HEDA) and (5-ethyl-1,3-dioxane-5-yl)methyl methacrylate (HEDMA) were synthesized by reaction between acryloyl and methacryloyl chloride with 5-ethyl, 5-hydroxymethyl, 1,3-dioxane. The kinetics of the polymerization of both are studied at different temperatures in benzene solution. Dilatometric techniques and nonlinear least-squares methods were used to obtain the kinetic data and to determine the kinetic constants, respectively. The values of k_p/k^1/2_t for the acrylic and methacrylic monomers are higher than those corresponding to methyl acrylate and methyl methacrylate, respectively. Important changes in k_p/k^1/2_t with temperature occur in the polymerization of HEDA, and the corresponding Arrhenius plot gives an activation energy of 5.6 kcal mol⁻¹. On the contrary, only slight changes with temperature are observed in this ratio for HEDMA and the activation energy associated with the polymerization reaction is ca. 1.7 kcal mol⁻¹. The stereo-structure of both polymers was determined by ¹³C-NMR spectroscopy and the molar fractions of tactic dyads, triads (and in the case of the methacrylic polymer also pentads) were determined from different resonance signals. Finally, the glass transition temperatures of both PHEDA and PHEDMA are 33 and 123°C, respectively. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 1125–1132, 1997     

Mesoporous Cu-Ce-Ox Solid Solutions from Spray Pyrolysis for Superior Low-Temperature CO Oxidation

Development of Pt group metal-free catalysts for low-temperature CO oxidation remains critical. In this work, active and stable mesoporous Cu-Ce-O_x solid solutions are prepared by using spray pyrolysis. The specific surface areas and pore volumes reach as high as 170 m² g⁻¹ and 0.24 cm³ g⁻¹, respectively. The results of CO oxidation study suggest that (1) the catalyst obtained by spray pyrolysis possesses much higher activity than those made by co-precipitation, sol-gel, and hydrothermal methods; (2) the optimal Cu_0.2-Ce_0.8-O_x solid solution presents a reactivity over 28 times that of both single-component CuO and CeO₂ at 70 °C. Based on the study of pure-phase Cu-Ce-O_x solid solutions by selective leaching of segregated CuO_x species, the active center for CO oxidation is confirmed as the bimetallic Cu-Ce-O site, whereas the individual CuO_x particles not only act as spectators but also block the active Cu-Ce-O sites. A low apparent activation energy of approximately 48 kJ mol⁻¹ is detected for CO oxidation at the Cu-Ce-O site, making Cu-Ce-O_x solid solutions able to present high activity at low temperature. Furthermore, the Cu-Ce-O_x catalysts exhibit excellent stability and thermal tolerance toward CO oxidation.     

Preparation and properties of inclusion compound of cyclopentadienylmanganese tricarbonyl complex with a ß-cyclodextrin dimer

The host-guest inclusion compound of cyclopentadienylmanganese tricarbonyl (guest) with ß-cyclodextrin dimer (host) bridged with two 1,2-diaminoethane has been prepared as the first example of cyclodextrin dimer inclusion compounds with organotransition metal complexes and characterized by elemental analysis and IR spectra as well as thermogravimetric analysis. The manganese complex included in the dimer is thermally more stable than the free complex. ¹H NMR spectroscopy has established that the cyclopentadienylmanganese complex and the dimer form an inclusion compound in aqueous solution with a stability constant (β₂, 195 mol⁻²l²) at 22°C. The spectroscopic studies and the results of elemental analysis revealed that stoichiometry (1:2, host: guest) of the inclusion compound in water is identical to its stoichiometry in solid state.     

Kinetics of the ene reactions of 4‐phenyl‐1,2,4‐triazoline‐3,5‐dione with β‐pinene and 2‐carene: Temperature,high pressure,and solvent effects

The data on temperature, solvent, and high hydrostatic pressure influence on the rate of the ene reactions of 4‐phenyl‐1,2,4‐triazoline‐3,5‐dione ( 1 ) with 2‐carene ( 2 ), and β‐pinene ( 4 ) have been obtained. Ene reactions 1 + 2 and 1 + 4 have high heat effects: ∆H_r‐n ( 1 + 2 ) −158.4, ∆H_r‐n( 1 + 4 ) −159.2 kJ mol⁻¹, 25°C, 1,2‐dichloroethane. The comparison of the activation volume (∆V^≠( 1 + 2 ) −29.9 cm³ mol⁻¹, toluene; ∆V^≠( 1 + 4 ) −36.0 cm³ mol⁻¹, ethyl acetate) and reaction volume values (∆V_r‐n( 1 + 2 ) −24.0 cm³ mol⁻¹, toluene; ∆V_r‐n( 1 + 4 ) −30.4 cm³ mol⁻¹, ethyl acetate) reveals more compact cyclic transition states in comparison with the acyclic reaction products 3 and 5 . In the series of nine solvents, the reaction rate of 1+2 increases 260‐fold and 1+4 increases 200‐fold, respectively, but not due to the solvent polarity.     

Hexacoordinated MIV (M=Ti,Zr, Hf) Tetrachlorido Complexes with Chelating Dithienylethane Based 1,2 Diketone Ligand – π-Conjugation as Decisive Factor for Axial Chirality Mode

1,2-bis(2,5-dimethylthiophen-3-yl)ethane-1,2-dione ( 1 , DTEthane) reacts with MCl₄ metal precursors of group four (M=Ti, Zr, Hf) via coordination of the carbonyl groups. The molecular structure of complex 2–4 were determined in scXRD studies in the solid state and characterized by means of multi-nuclear and multi-dimensional NMR spectroscopy in solution. While the resulting titanium complex [TiCl₄(DTEthane)] 2 shows a monomeric structure, where 1 binds in a bidentate fashion, complexes with a Zr ( 3 ) and Hf ( 4 ) center have dimeric scaffolds in which the ligands adopt a bridging mode. Quantum chemical calculations using density functional theory (G16, B97D3/def2-TZVP) were used to evaluate the general trend of dimer formation (Ti<Zr<Hf). The molecular structures derived from both scXRD and the DFT optimized structures reveal the carbonyl groups in conjugation with the adjacent thiophene substituent. As a result, they are coplanar and rotation about the two C−C axes (C1−C7; C8−C9) is restricted allowing for only one chiral axis along C7−C8. This gains special importance with respect to previously described complexes carrying the closely related 1,2-endiolato ligand (1,2-bis(2,5-dimethylthiophen-3-yl)ethene-1,2-diolate), in which no coplanarity of the thiophene rings to their neighboring metallacycle was observed allowing for two chiral axes. Noteworthy, further DFT calculations addressing the pathway of racemization found transition states, which are characterized by contrary rotations of both thiophene rings and a loss of conjugation rather than a direct rotation around the axis C7−C8.     

Two-phase catalytic NBR hydrogenation by RuHCl(CO)(PCy3)2 immobilized in 1-butyl-3-methylimidazolium tetrafluoroborate molten salt

RuHCl(CO)(PCy₃)₂ ( 1 ) dissolved in 1-butyl-3-methylimidazolium tetrafluoroborate ( 2 ) molten salt is able to reduce selectively NBR to HNBR under hydrogen partial pressures between 10 and 40 bar at 100–160°C in a typical two-phase catalytic reaction. Reaction rates between 0.059 (mmol Ru)⁻¹ · min⁻¹ and 1.65 (mmol Ru)⁻¹ · min⁻¹ were obtained depending on the reaction parameters and increasing with the volume of the molten salt. The overall process has an apparent activation energy of 47 ± 3 kJ · mol⁻¹. The recovered ionic catalyst solution can be reused several times without significant changes in the catalytic performance (selectivity and activity).     

Kinetics and mechanisms of the reactions of aluminium(III) with β-diketones in aqueous solution

The kinetics and mechanisms of the reactions of aluminium(III) with pentane-2,4-dione (Hpd), 1,1,1-trifluoro pentane-2,4-dione (Htfpd) and heptane-3,5-dione (Hhptd) have been investigated in aqueous solution at 25°C and ionic strength 0.5 mol dm⁻³ sodium perchlorate. The kinetic data are consistent with a mechanism in which aluminium(III) reacts with the β-diketones by two pathways, one of which is acid independent while the second exhibits a second-order inverse-acid dependence. The acid-independent pathway is ascribed to a mechanism in which [Al(H₂O)₆]³⁺ reacts with the enol tautomers of Hpd, Htfpd, and Hhptd with rate constants of 1.7(±1.3)×10⁻², 0.79(±0.21), and 7.5(±1.6)×10⁻³ dm³ mol⁻¹ s⁻¹, respectively. The inverse acid pathway is consistent with a mechanism in which [Al(H₂O)₅(OH)]²⁺ reacts with the enolate ions of Hpd, Htfpd, and Hhptd with rate constants of 4.32(±0.18)×10⁶, 5.84(±0.24)×10³, and 1.67(±0.05)×10⁷ dm³ mol⁻¹ s⁻¹, respectively. An alternative formulation involves a pathway in which [Al(H₂O)₄(OH)₂]⁺ reacts with the protonated enol tautomers of the ligands. This gives rate constants of 2.79(±0.12)×10⁴, 3.86(±0.16)×10⁵, and 8.98(±0.25)×10³ dm³ mol⁻¹ s⁻¹ for reaction with Hpd, Htfpd, and Hhptd, respectively. Consideration of the kinetic data reported here together with data from the literature, suggest that [Al(H₂O)₅(OH)]²⁺ reacts by an associative or associative-interchange mechanism. © 1998 John Wiley & Sons, Inc. Int J Chem Kinet 30: 257–266, 1998.     

Synthesis,Enantiomeric Conformations,and Stereodynamics of Aromatic ortho‐Substituted Disulfones

Aromatic ortho‐disulfone derivatives are readily accessible from diiodide precursors by Cu^I‐mediated reaction with sodium sulfinate salts (DMF, 110°). The sulfonyl substituents adopt in solution and in the solid state two enantiomeric conformations (λ and δ) as evidenced by ³¹P‐ and ¹H‐NMR data of the chiral D₃‐symmetric tris{4,5‐bis[(4‐methylphenyl)sulfonyl]benzene‐1,2‐diolato(2?)‐κO,κO′}phosphate(v) anion ( 3a ) and 1,2‐bis(camphor‐10‐sulfonyl)‐4,5‐dimethoxybenzene ((=1,2‐bis{{[(1S,4R)‐7,7‐dimethyl‐2‐oxobicyclo[2.2.1]hept‐1‐yl]methyl}sulfonyl}‐4,5‐dimethoxybenzene; 6c ). X‐Ray structure analysis of 1,2‐dimethoxy‐4,5‐bis(methylsulfonyl)benzene ( 6a ) and 1,2‐dimethoxy‐4,5‐bis(4‐methylphenyl)sulfonyl]benzene ( 6b ) confirmed in the solid state the preferred chiral orientation of the sulfonyl groups. Dynamic conformational isomerism was detected for 6c in its ¹H‐NMR in the temperature range of 110°, the corresponding free energy being 19.8 kcal?mol^?1.     

Computational and dynamic NMR investigation of 2,2-dimesityl-1,1,1,3,3,3-hexamethyltrisilane

The structure and rotational barrier for the mesityl-silicon bond of 2,2-dimesityl-1,1,1,3,3,3-hexamethyltrisilane have been investigated by ¹H- and ¹³C-variable temperature nuclear magnetic resonance (NMR) as well as by density functional theory structural calculations. The calculations show that the lowest energy structure has C₂ symmetry with nonequivalent ortho methyl groups, consistent with the crystal structure and solution NMR. The nonequivalent ortho methyl groups exchange through a C_s transition state with a calculated relative free energy of 11.0 kcal mol⁻¹. The barrier for this rotation found by dynamic NMR is 13.4 ± 0.2 kcal mol⁻¹ at 298 K.     

Exploring the Mechanism of a Chiral N-Alkyl Imine-Based Light-Driven Molecular Rotary Motor at MS-CASPT2//CASSCF and MS-CASPT2//(TD) DFT Levels

The working mechanism including the photoisomerization and thermal isomerization steps of a chiral N-alkyl imine-based motor synthesized by Lehn et al. are revealed by MS-CASPT2//CASSCF and MS-CASPT2//(TD-)DFT methods. For the photoisomerization process of the imine-based motor, it involves both the bright (π,π*) state and the dark (n,π*) state. In addition, the MECI has similar geometry and energy to the minimum of the S₁ state, which shows that the process is barrierless and keeps the unidirectionality of rotation well; the result confirms the imine-based motor is a good candidate for a light-driven molecular rotary motor. For the thermal isomerization process of the imine-based motor, there are two even isomerization paths: one with the mechanism of the in-plane N inversion, the energy barriers of which are 29.6 kcal mol⁻¹ at MS3-CASPT2//CAM-B3LYP level and 29.2 kcal mol⁻¹ at MS3-CASPT2//CASSCF level; the other with the mechanism of ring inversion of the cycloheptatriene moiety, with energy barriers of 28.1 kcal mol⁻¹ at MS3-CASPT2//CAM-B3LYP level and 18.1 kcal mol⁻¹ at MS3-CASPT2//CASSCF level. According to the structural feature of the stator moiety, the imine molecule can be used as a two-step or a four-step light-driven rotary motor.