The Alkaline Hydrolysis of Sulfonate Esters: Challenges in Interpreting

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1 Supporting Information for: The Alkaline Hydrolysis of Sulfonate Esters: Challenges in Interpreting Experimental and Theoretical Data Fernanda Duarte 1, Ting Geng 1, Gaël Marloie 1, Adel O. Al Hussain 2, Nicholas H. Williams 2, * and Shina Caroline Lynn Kamerlin 1, * 1. Department of Cell and Molecular Biology, Uppsala University 2. Department of Chemistry, The University of Sheffield 1 kamerlin@icm.uu.se 2 n.h.williams@sheffield.ac.uk

2 Table of Contents Figure S1: Minimum energy paths obtained from IRC calculations....s3 Figure S2: 2-D Energy Surface for 4-nitrophenyl, 4-cyanophenyl, 3-nitrophenyl, and phenyl benzenesulfonates s3 Figure S3: Key Distances at transition state for the alkaline hydrolysis of 4- nitrophenyl, 4-cyanophenyl, 3-cyanophenyl and phenyl benzenesulfonates....s4 Figure S4: Atomic charges calculated at transition state geometry s5 Figure S5: Kinetic data for hydrolyses of S6 Discussion of sigma values used in Hammett plots s7 Figure S6: Analysis of hydroxide promoted hydrolysis of methyl aryl diesters...s9 Figure S7: Comparison of calculated and experimental log k including compounds S12 Table S1: Calculated solvation free energies for the hydroxide ion using different density functionals s13 Table S2: Energy decomposition for G calc using different functionals...s14 Table S3: Comparison of the S-O nuc/lg distances at the TS for the different functionals tested in this work) s15 Table S4: Energy decomposition for G calc and S-O lg/nuc distances at the transition state for compounds S16 Table S5: Absolute electronic energies and entropies at M06-2X /6311+G** level of theory s17 Table S6: Absolute electronic energies and entropies at B3LYP /6311+G** level of theory s18 Table S7: Absolute electronic energies and entropies at CAM-B3LYP/6311+G** level of theory s19

3 Table S8: Absolute electronic energies and entropies at ω-b97x-d /6311+G** level of theory s20 Table S9: Absolute electronic energies and entropies for compounds 1-3 at M06-2X /6311+G** level of theory s21 Cartesian Coordinates for Key Stationary Points S23 S2

The final points (solid circles) in (A) correspond to structures obtained by performing geometry optimization on the endpoints of the IRC calculations.

4 Figure S1: (A) Overlay of the minimum energy paths obtained from IRC calculations on the optimized transition states for compounds shown in Fig. 4, and (B) changes in S-O nuc and S-O lg distances along the reaction coordinate for a representative compound (3,4-dimethyl benzene sulfonate). The final points (solid circles) in (A) correspond to structures obtained by performing geometry optimization on the endpoints of the IRC calculations. Energy [kcal/mol] A 3-F-4-NO 2 4-NO 2 4-CN 3-NO 2 3-CN 4-Cl H 3-4-CH 3 Energy[kcal/mol] B 34-CH Distances [A] S-O lg S-O nuc Figure S2. Energy landscapes for the alkaline hydrolysis of aryl benzenesulfonate, shown here are: 4-nitrophenyl, 4-cyanophenyl, 3-nitrophenyl, and phenyl benzenesulfonates. The approximate positions of the relevant transition states are indicated by, and the actual optimized structures are shown in Fig. S3. S3

5 Figure S3: Geometries of optimized transition state for the alkaline hydrolysis of (A) 4-nitrophenyl, (B) 4-cyanophenyl, (C) 3-cyanophenyl and (D) phenyl benzenesulfonates. These structures were obtained by optimization of the approximate transition states highlighted on the surfaces shown in Fig. S2. (A) (B) (C) (D) S4

6 Figure S4: Atomic charges of oxygen atoms of the nucleophile and leaving group in the transition state for the different functionals tested in this work. All charges are derived either from the ChElPG point selection scheme 1 using either the 6-31G* (A and B respectively) or G** (C and D respectively) basis sets, or from natural population analysis (E and F respectively) using the G** basis set. O nuc Charge -1 (A) (B) M062X B3LYP B97X-D CAM-B3LYP F-4NO 2 4-NO 2 4-CN 3-NO 2 3-CN 4-Cl H 34-CH F-4NO 2 4-NO 2 4-CN 3-NO 2 3-CN 4-Cl H 34-CH pk a (ArOH) pk a (ArOH) O lg Charge (C) (D) M062X B3LYP B97X-D CAM-B3LYP O nuc Charge O lg Charge F-4NO 2 4-NO 2 4-CN 3-NO 2 3-CN 4-Cl H 34-CH 3 3-F-4NO 2 4-NO 2 4-CN 3-NO 2 3-CN 4-Cl H 34-CH pk a (ArOH) pk a (ArOH) (E) (F) M062X B3LYP B97X-D CAM-B3LYP O nuc Charge O lg Charge F-4NO 2 4-NO 2 4-CN 3-NO 2 3-CN 4-Cl H 3-4dimet pk a (ArOH) F-4NO 2 4-NO 2 4-CN 3-NO 2 3-CN 4-Cl H 3-4dimet pk a (ArOH) S5

7 Figure S5: Plots of observed rate constants for reactions of 1 3 against concentration of hydroxide Hydrolysis of 1 k obs (s -1 ) versus [KOH] 50 C, I = 0.5 M (KCl) k obs / s m1 m2 Chisq R [KOH] y = m1*m0+m2 Value Error e e-8 NA [KOH] Compound 1 k obs s Hydrolysis of 2 k obs (s -1 ) versus [KOH] 50 C, I = 0.5 M (KCl) NA k obs / s [KOH] Compound 2 k obs s S6 m1 m2 Chisq R 2 [KOH] y = m1*m0+m2 Value Error e-5 NA NA

8 0.12 Hydrolysis of 3 k obs (s -1 ) versus [KOH] 50 C, I = 0.5 M (KCl) k obs / s m1 m2 Chisq R [KOH] y = m1*m0+m2 Value Error e-5 NA [KOH] Compound 3 k obs s NA S7

9 Sigma values used to correlate the kinetic data: Substituted phenol pk a Log k obs s -1 σ 3-F-4-NO NO CN NO CN Cl Parent ,4-dimethyl Leaving group pk a Log k obs s -1 σ (OH) σ (CO 2 H) 3-pyridinyl, N-oxide, N-methyl, If the sigma values for the pyridyl leaving groups are defined by using the ionisation of a carboxylic acid in the 3 position (as defined for the substituted benzene rings), the correlation is good but the pyridyl substituents all show a negative deviation: log (k / s -1 ) obs ! These are probably all slight underestimates, as the inductive and field effect of the N in the ring is likely to be proportionally greater for ionisation of OH than for ionisation of CO 2 H in the 3 position (as the "substituent" is closer to the site of ionisation). If the sigma values are defined by using the relationship between pk a and non-resonance substituents for phenols (ρ = 2.113), there is an excellent correlation between all the compounds that do not have 4-substitutents capable of providing direct delocalisation of the oxyanion: S8

10 log (k / s -1 ) obs ! Thus, we have used the values defined this way. This of course assumes (rather than shows) that the correlation is not achieved via delocalisation, but is due to stronger inductive and field effects. If we use the parameters defined by carboxylic acid ionisation, then the Hammett correlation is still very satisfactory, but the slight concave curvature is less evident: log (k obs / s -1 ) ! Finally, we have performed calculations of the hydrolysis of compounds 1 to 3 using the M06-2X functional (Table S4), and, while we once again under-estimate the energetics, these compounds otherwise follow the experimental trend, and hydrolysis proceeds through concerted transition states similar to those observed for the other compounds. S9

11 Figure S6: Analysis of hydroxide promoted hydrolysis of methyl aryl diesters. Re-analysing the hydrolysis of diesters reported in ref. 2 in terms of a Yukawa-Tsuno analysis yields a value of 0.33 for r (i.e. optimising for r and ρ when correlating log k against ρ +r(σ - -σ)) Plotting the data against sigma (A), sigma minus (B) or the composite abscissae (C) clearly shows that the composite parameter gives the best correlation. This depends primarily on the data points for 4-nitro and 4-cyano, as discussed by the authors in the SI for the original paper. This analysis lends some quantification to the degree of asynchronicity or resonance demand in the transition state for this reaction, which appears to be more significant than for the sulfonate esters. log (k HO- / M -1 s -1 ) -5 (A) log (k HO- / M -1 s -1 ) -5 (B) log (k HO- / M -1 s -1 ) -5 (C) ! ! " ! (! " -!) A: 2.4±0.2, R 2 = B: 1.7±0.2, R 2 = C: 2.21±0.08, R 2 = Substituted pk a Log k M -1 s -1 σ σ - σ (σ - σ) phenol 4-NO Cl-3-NO CN NO ,4-dichloro Cl F Cl F parent S10

12 Figure S7: A comparison of calculated (pink) and experimental (blue) log k obtained when taking into account trends in log k calc obtained from considering just E (A) and also when including zero point energy and entropy corrections (B) to obtain the activation free energies, obtained using the M06-2X functional, and now also including compounds 1 3. As can be seen, when including zero point energy and entropy corrections, the plots scatter with the biggest deviation in the 3,4-dimethyl substituted compound, but E follows experiment quite well. 6 3 (1A) (1B) log (k OH ) calc log (k OH ) exp F-4NO 2 4NO 2 4CN 3NO 2 3CN 4Cl H 34-CH pk a (ArOH) 0 3F-4NO 2 4NO 2 4CN 3NO 2 3CN 4Cl H 34-CH pk a (ArOH) S11

13 Table S1: Calculated solvation free energies for the hydroxide ion using different density functionals, the SMD solvation model and the G** basis set, in kcal/mol. Included here is also the correction applied in order to obtain better agreement with the experimental solvation free energy of kcal/mol (see discussion in main text). Functional ΔG solv,calc G solv,calcà exp M06-2X B3LYP ω-b97x-d CAM- B3LYP S12

14 Table S2: Energy Decomposition for G calc using different functionals a. Functional M06-2X B3LYP ω-b97x-d CAM- B3LYP 3-F-4- NO 2 4- NO 2 4-CN 3- NO 2 3-CN 4-Cl H 3,4- dimethyl pka ZPE b ΔE gas ΔΔG sol TΔS b ΔG calc ZPE b ΔE gas ΔΔG sol TΔS b ΔG calc ZPE b ΔE gas ΔΔG sol TΔS b ΔG calc ZPE b ΔE gas ΔΔG sol TΔS conf c ΔG calc a All energies are in kcal/mol, relative to the reactant complex. b Zero point energies and entropies were obtained from frequency calculations at K, as outlined in the main text. S13

15 Table S3: Comparison of the S-O nuc/lg distances at the TS for the different functionals tested in this work a. Functional M06-2X B3LYP ω-b97x-d CAM-B3LYP 3-F-4- NO 2 4-NO 2 4-CN 3-NO 2 3-CN 4-Cl H 3,4- dimethyl pk a S-O nuc S-O lg S-O nuc S-O lg S-O nuc S-O lg S-O nuc S-O lg a All distances are given in Å. S14

16 Table S4: Energy decomposition for G calc and S-O lg/nuc distances at the transition state for compounds 1 to 3 (Fig. 3), calculated using the M06-2X functional a. Experimental values have been calculated for the cage contribution, as discussed in the main text pk a ZPE ΔE gas ΔΔG sol TΔS conf ΔG calc G exp S-O lg S-O nuc a All distances are in Å and all energies are in kcal/mol. For definition of individual energy contributions, see footnote to Table S2. S15

17 Table S5: Absolute electronic energies (a.u) and entropies (cal/mol K) for reactant and transition state structures used to calculate ΔG calc and log k calc at the M06-2X/6311+G** level of theory. Species E el (gas) /a.u E el (solv) a / a.u EZPV /a.u S /Cal/Mol K ν / cm -1 X=3F-4NO 2 Reactant TS X=4NO2 Reactant TS X=4CN Reactant TS X=3NO2 Reactant TS X=3CN Reactant TS X=4Cl Reactant TS X=H Reactant TS X=3,4-CH3 Reactant TS a E el (solv) reported here does not include correction by solvation of hydroxide, for this correction please see Table S1 S16

18 Table S6: Absolute electronic energies (a.u) and entropies (cal/mol K) for reactant and transition state structures used to calculate ΔG calc and log k calc at the B3LYP/6311+G** level of theory. Species E el (gas) /a.u E el (solv) a / a.u EZPV /a.u S /Cal/Mol K ν / cm -1 X=3F-4NO 2 Reactant TS X=4NO2 Reactant TS X=4CN Reactant TS X=3NO2 Reactant TS X=3CN Reactant TS X=4Cl Reactant TS X=H Reactant TS X=3,4-CH3 Reactant TS a E el (solv) reported here does not include correction by solvation of hydroxide, for this correction please see Table S1 S17

19 Table S7: Absolute electronic energies (a.u) and entropies (cal/mol K) for reactant and transition state structures used to calculate ΔG calc and log k calc at the CAM-B3LYP/6311+G** level of theory. Species E el (gas) /a.u E el (solv) a / a.u EZPV /a.u S /Cal/Mol K ν / cm -1 X=3F-4NO 2 Reactant TS X=4NO2 Reactant TS X=4CN Reactant TS X=3NO2 Reactant TS X=3CN Reactant TS X=4Cl Reactant TS X=H Reactant TS X=3,4-CH3 Reactant TS a E el (solv) reported here does not include correction by solvation of hydroxide, for this correction please see Table S1 S18

20 Table S8: Absolute electronic energies (a.u) and entropies (cal/mol K) for reactant and transition state structures used to calculate ΔG calc and log k calc at the ω-b97x-d /6311+G** level of theory. Species E el (gas) /a.u E el (solv) a / a.u EZPV /a.u S /Cal/Mol K ν / cm -1 X=3F-4NO 2 Reactant TS X=4NO2 Reactant TS X=4CN Reactant TS X=3NO2 Reactant TS X=3CN Reactant TS X=4Cl Reactant TS X=H Reactant TS X=3,4-CH3 Reactant TS a E el (solv) reported here does not include correction by solvation of hydroxide, for this correction please see Table S1 S19

21 Table S9: Absolute electronic energies (a.u) and entropies (cal/mol K) for reactant and transition state structures for compounds 1-3 (Figure 3) used to calculate ΔG calc and log k calc at the M06-2X /6311+G** level of theory. Species E el (gas) /a.u E el (solv) a / a.u EZPV /a.u S /Cal/Mol K ν / cm -1 1 Reactant TS Reactant TS Reactant TS S20

22 References (1) Breneman, C. M.; Wiberg, K. B. J. Comp. Chem. 1990, 11, 361. (2) Zalatan, J. G.; Herschlag, D. J. Am. Chem. Soc. 2006, 128, S21

23 Cartesian Coordinates for Key Stationary Points For the position of the substituent, X, see Scheme 1 of the main text. M06-2X Functional X=3-F-4NO 2 Reactant Complex S O O C C C C C C H H H H H O C C C C C C H F N H H O H O O Transition State S O O C C C C C C H H H H H O C S22

24 C C C C C H F N H H O H O O Product state S O O C C C C C C H H H H H O C C C C C C H F N H H O H O O X=4NO 2 Reactant Complex S O O C C C C C C H S23

25 H H H H O C C C C C C H H N H H O H O O Transition State S O O C C C C C C H H H H H O C C C C C C H H N H H O H O O Product state S O O C C C S24

26 C C C H H H H H O C C C C C C H H C H H O H N X=4CN Reactant Complex S O O C C C C C C H H H H H O C C C C C C H H C H H O H N Transition State S25

27 S O O C C C C C C H H H H H O C C C C C C H H C H H O H N Product state S O O C C C C C C H H H H H O C C C C C C H H C H H O H N S26

28 X=3-NO 2 Reactant Complex S O O C C C C C C H H H H H O C C C C C C H N H H H O H O O Transition State S O O C C C C C C H H H H H O C C C C C C H N H S27

29 H H O H O O Product state S O O C C C C C C H H H H H O C C C C C C H N H H H O H O O X=3-CN Reactant Complex S O O C C C C C C H H H H H O C C S28

30 C C C C H C H H H O H N Transition State S O O C C C C C C H H H H H O C C C C C C H C H H H O H N Product state S O O C C C C C C H H H H H O S29

31 C C C C C C H C H H H O H N X=4-Cl Reactant Complex S O O C C C C C C H H H H H O C C C C C C H H Cl H H O H Transition State S O O C C C C C C H H S30

32 H H H O C C C C C C H H Cl H H O H Product state S O O C C C C C C H H H H H O C C C C C C H H Cl H H O H X=H Reactant Complex S O O C C C C C S31

33 C H H H H H O C C C C C C H H H H H O H Transition State S O O C C C C C C H H H H H O C C C C C C H H H H H O H Product state S O O C C C C C C S32

34 H H H H H O C C C C C C H H H H H O H X=3,4-CH 3 Reactant Complex S O O C C C C C C H H H H H O C C C C C C H H C C H O H H H H H H H Transition State S33

35 S O O C C C C C C H H H H H O C C C C C C H H C C H O H H H H H H H Product state S O O C C C C C C H H H H H O C C C C C C H H C S34

36 C H O H H H H H H H S35

37 B3LYP Functional X=3-F-4NO 2 Reactant Complex S O O C C C C C C H H H H H O C C C C C C H F N H H O H O O Transition State S O O C C C C C C H H H H H O C C C C C S36

38 C H F N H H O H O O X=4NO 2 Reactant Complex S O O C C C C C C H H H H H O C C C C C C H H N H H O H O O Transition State S O O C C C C C C H H H H S37

39 H O C C C C C C H H N H H O H O O X=4CN Reactant Complex S O O C C C C C C H H H H H O C C C C C C H H C H H O H N Transition State S O O C C C C S38

The Alkaline Hydrolysis of Sulfonate Esters: Challenges in Interpreting Experimental and Theoretical Data

pubs.acs.org/joc Terms of Use The Alkaline Hydrolysis of Sulfonate Esters: Challenges in Interpreting Experimental and Theoretical Data Fernanda Duarte, Ting Geng, Gae l Marloie, Adel O. Al Hussain, Nicholas