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question:Figure 3. Racemization reaction path of derivative 1 in CHCl 3 calculated by NEB/xTB1 presented in the form of 43 geometrically optimized images. The images corresponding to the structures of the saddle points (SP) and the intermediate point (IS) are marked in red. - rephrase this
answer:The racemization reaction pathway of derivative 1 in CHCl3 was analyzed using NEB/xTB1, and the results were presented in the form of 43 optimized images. The images marked in red represent the structures of the saddle points (SP) and the intermediate point (IS).
question:Figure 4. Activation energies of racemization E A F and back reaction E AB together with geometrically optimized B97-3c in CHCl 3 structures TS 1 , TS 2 and IS for derivative 1. - rephrase this
answer:In Figure 4, the activation energies of the racemization process (ΔEA_F) and the back reaction (ΔEA_B) were determined using geometrically optimized B97-3c structures for derivative 1 in CHCl3. The corresponding structures for the transition states (TS1 and TS2) and the intermediate state (IS) were also included.
question:Table 1 summarizes the activation energies E A F and E A B (kcal/mol) for AMD-R[4]A derivatives calculated by selected HF methods, and DFT on geometries calculated by the B97-3c method, respectively. The activation energies found with the B38LYP-D4 method are closest to the reference values, which were considered the values of activation energies calculated with the DH-revDSD-PBEP86-D4 double hybrid functional. The largest absolute error of this method for the racemization activation energy E A F = 0.82 kcal/mol was found for the derivative 4 DE A B = 0.44 kcal/mol for the derivative 3 . It is worth mentioning that the calculations performed with the same number of processors in the case of the B38LYP method are about twenty times faster than the double hybrid method. Particularly fast (approx. 60 times) from the double hybrid is the DFT method using the r2scan-3c functional. For this method, the largest absolute deviations from the reference values were as follows: E A F = 3.28 kcal/mol for derivative 6 and E A B = 0.82 kcal/mol for derivative 7 . In turn, calculations using the M062X functional gave the largest deviations E A B = 3.78 kcal/mol and E A B = 1.27 kcal/mol for derivative 4. - rephrase this
answer:Table 1 presents the activation energies (ΔEA_F and ΔEA_B) in kcal/mol for AMD-R[4]A derivatives. The calculations were performed using selected HF methods and DFT on geometries obtained from the B97-3c method. The activation energies determined with the B38LYP-D4 method were found to be closest to the reference values obtained from the DH-revDSD-PBEP86-D4 double hybrid functional. The largest absolute error of the B38LYP-D4 method was 0.82 kcal/mol for the racemization activation energy (ΔEA_F) of derivative 4, while the activation energy of the back reaction (ΔEA_B) had a deviation of 0.44 kcal/mol for derivative 3. It is worth noting that the B38LYP calculations were significantly faster, approximately twenty times faster, compared to the double hybrid method when performed with the same number of processors. Similarly, the DFT method using the r2scan-3c functional was approximately sixty times faster than the double hybrid method. However, this method exhibited larger absolute deviations from the reference values, with ΔEA_F being 3.28 kcal/mol for derivative 6 and ΔEA_B being 0.82 kcal/mol for derivative 7. The M062X functional calculations resulted in the largest deviations, with ΔEA_B being 3.78 kcal/mol and ΔEA_B being 1.27 kcal/mol for derivative 4.
question:It was experimentally found (Figure 2C) that the molecule 2 becomes more rigid in more non-polar solvents than CHCl 3 such as benzene and CCl 4 . This was confirmed by calculations using the B38LYP-D4 method of the height of racemization barriers E A F in benzene and CCl 4 using the SMD solvent model. The calculated racemization activation energies are respectively: in benzene E A F = 42.69 kcal/mol, in CCl 4 E A F = 42.64 kcal/mol and are more than 5.1 kcal/mol higher than the activation barrier in CHCl 3 ( E A F = 37.50 kcal/mol). However, we do not observe practically any change in the activation energy of the back reaction, which for benzene and CCl 4 are respectively: E A B = 15.36 kcal/mol and E A B = 15.26 kcal/mol, while for CHCl 3 it is E A B = 15.31 kcal/mol. - rephrase this
answer:Experimental findings (Figure 2C) revealed that molecule 2 exhibits increased rigidity in non-polar solvents such as benzene and CCl4 compared to CHCl3. This observation was further supported by calculations using the B38LYP-D4 method, which determined the height of the racemization barriers (ΔEA_F) in benzene and CCl4 using the SMD solvent model. The calculated racemization activation energies for benzene and CCl4 were 42.69 kcal/mol and 42.64 kcal/mol, respectively, indicating an increase of more than 5.1 kcal/mol compared to the activation barrier in CHCl3 (ΔEA_F = 37.50 kcal/mol). However, negligible changes were observed in the activation energy of the back reaction, with values of ΔEA_B = 15.36 kcal/mol for benzene, ΔEA_B = 15.26 kcal/mol for CCl4, and ΔEA_B = 15.31 kcal/mol for CHCl3.