Cethrene: The Chameleon of Woodward Hoffmann Rules

Transcription

1 Supporting Information Cethrene: The Chameleon of Woodward Hoffmann Rules Tomáš Šolomek,*, Prince Ravat,, Zhongyu Mou, Miklos Kertesz, and Michal Juríček*,, Department of Chemistry, University of Basel, St. Johanns-Ring 19, CH-4056 Basel, Switzerland Department of Chemistry, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo , Japan Department of Chemistry and Institute of Soft Matter, Georgetown University, 37 th and O Streets Washington, DC , United States Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland Table of Contents S1. Kinetic Measurements S2 Table S1 S2 Figure S1 S2 S2. Irradiation Experiments S3 Figure S2 S3 Figure S3 S3 Figure S4 S4 Figure S5 S4 S3. Quantum Chemical Calculations S5 Table S2 S5 Table S3 S5 Table S4 S6 Table S5 S6 Table S6 S6 Table S7 S7 Table S8 S7 Table S9 S7 S4. References S7 S5. Cartesian Coordinates S8

2 S1. Kinetic Measurements Table S1. Rate constants a obtained by global fit of the experimental data at different temperatures. Temperature / K k 3b-form / s 1 k 3b-dec / s a Note that k 3b-form is assumed to be a pseudo-first-order rate constant when 10 equiv of p-chloranil are used. Figure S1. The Arrhenius plot of electrocyclization of 3b in toluene. S2

3 S2. Irradiation Experiments Figure S2. Time (t) evolution of absorbance (A) at 485 nm of samples of 3b in toluene prepared by oxidation of its dihydro-precursor with p-chloranil (CA). Irradiation (λ = 660 nm; 30s) of 3b in the samples is indicated by an arrow (1 equiv CA, black; 3 equiv CA, red). Figure S3. Time (t) evolution of absorbance (A) at 485 nm of a sample of 3b in toluene prepared by oxidation of its dihydro-precursor with 3 equiv of p-chloranil. Repeated irradiations (λ = 660 nm; 30s) of 3b in the sample are indicated by red arrows. S3

4 Figure S4. Spectral evolution of a sample of 3b in toluene prepared by oxidation of its dihydroprecursor with 3 equiv of p-chloranil. The jumps in absorbance in the spectra are a consequence of repeated irradiations (λ = 660 nm; 30s) of the sample. Figure S5. Spectral evolution of 4b in a sample of 3b in toluene prepared by oxidation of its dihydro-precursor with 3 equiv of p-chloranil. Repeated irradiations (λ = 660 nm; 30s) of the sample are denoted by ON. S4

5 S3. Quantum Chemical Calculations Table S2. The first two electronic transitions a in 4a and anti-5a. B3LYP CAM-B3LYP BMK M05-2X Compound 4a Compound anti-5a 487 (0.6487) 444 (0.0224) 412 (0.0009) 434 (0.0001) 429 (0.8426) 373 (0.0052) 371 (0.0009) 352 (0.0000) 444 (0.7972) 391 (0.0124) 379 (0.0012) 372 (0.0001) 426 (0.8684) 365 (0.0019) 375 (0.0089) 350 (0.0000) 426 (0.8391) 375 (0.0118) M06-2X 371 (0.0018) 356 (0.0000) a The first two electronic transitions (in nm) and oscillator strengths (in parentheses) were obtained with gas-phase TD-DFT/6-31G(d) calculations on geometries optimized with the same functional and basis set. Table S3. A comparison of the restricted and spin-unrestricted broken-symmetry formalism DFT calculations of cethrene (3a). E / CAMkcal mol 1 B3LYP BLYP BMK B3LYP M05-2X M06-2X M06L a E BS E RS 0.0 ( 0.8) N/A b 0.1 ( 1.3) 2.7 ( 4.5) 0.8 ( 2.1) N/A b 0.0 ( 0.4) a The energy difference of singlet 3a calculated using spin-unrestricted broken-symmetry (BS) formalism and restricted (RS) formalism. This includes gas-phase geometry optimization with the respective functional (6-31G(d) basis set) followed by a single-point energy calculation on the optimized geometries (cc-pvtz basis set). The numbers in the parentheses include ZPVEs. b No instability was found for the Kohn Sham wavefunctions computed with the restricted formalism. S5

6 Table S4. DFT-calculated reaction energies. a Table S5. Reaction barrier a of 3a anti-5a of the C 2 symmetric EC calculated with other methods. E / kcal mol 1 M05-2X CAS(2,2) b CAS(10,10) b UHF B3LYP-D3 E / CAMkcal mol 1 B3LYP BLYP BMK B3LYP M05-2X M06-2X M06L 3a RS anti-5a a BS anti-5a 5.3 N/A b N/A b 3.8 3a RS syn-5a a BS syn-5a 6.4 N/A b N/A b a anti- 3 5a a Reaction energies (in kcal mol 1 at 0 K) calculated (cc-pvtz basis set) with the respective functional on 6-31G(d) geometries with ZPVEs. b Not applicable; see footnote [b] in Table S3; energies obtained with the restricted formalism should be used here to compare to other DFT methods. B3LYP- D3BJ 3a anti-5a c 23.6 c a All using 6-31G(d,p) basis set. b Based on the UM052X/6-31G(d,p) optimized geometries. c Frequency calculation option is not available for CAS calculation. The ZPVE correction at the UM05-2X/6-31G(d,p) level of 0.7 kcal mol 1 is included. Table S6. DFT-calculated singlet triplet gaps. a E / CAMkcal mol 1 B3LYP BLYP BMK B3LYP M05-2X M06-2X M06L 3a RS 3 3a a BS 3 3a 6.8 N/A b N/A b 7.0 anti-5a anti- 3 5a a Energies (in kcal mol 1 at 0 K) calculated (cc-pvtz basis set) with the respective functional on 6-31G(d) geometries with ZPVEs. b Not applicable; see footnote [b] in Table S3. S6

7 Table S7. Comparison of reaction barriers and energies of 3a (R = H) and 3b (R = Ph). a E corr / kcal mol 1 Reaction barrier Reaction energy E corr / kcal mol 1 Reaction barrier Reaction energy 3a BS anti-5a b BS anti-5b a BS syn-5a b BS syn-5b a All using M05-2X and 6-31G(d,p) basis set with ZPVEs. Table S8. Solvation Gibbs free energies a (in kcal mol 1 ) of 3a RS and TS[3a anti-5a] -BS obtained by the SMD [S1] solvation method, and the reaction energy b of 3a RS anti-5a in the gas phase, toluene, and dichloromethane. Entry Gas phase Toluene Dichloromethane 3a RS N/A c TS[3a anti-5a] -BS N/A c a RS anti-5a 22.4 b 22.7 b 22.8 b a The solvation free energy was calculated at the B3LYP/cc-pVTZ level of theory subtracting the gas-phase electronic energy from the electronic energy obtained with the SMD solvation. b ZPVE correction included in the gas-phase energy; ZPVE and solvation-free energy included in the solution-phase energies. c Not applicable. Table S9. Energy corrections to ZPVE, enthalpy, and Gibbs free energy for the reaction 3a RS anti-5a calculated by the DFT methods. a E corr / CAMkcal mol 1 B3LYP BLYP BMK B3LYP M05-2X M06-2X M06L ZPVE Enthalpy Gibbs energy a The energy corrections were calculated with 6-31G(d) basis set according to the rigid rotor and harmonic oscillator approximation using standard statistical thermodynamics formulae for ideal gas. Both the local minima of 3a RS and the transition-state structures display the same number and comparable magnitudes of soft vibrational modes which erroneous contributions to entropy are expected to roughly cancel out. S4. References [S1] Marenich, A. V.; Cramer, C. J.; Truhlar, D. G. J. Phys. Chem. B 2009, 113, S7

8 S5. Cartesian Coordinates 3a -RS, RB3LYP/6-31G(d), E = Hartree S8

9 3a -BS, UB3LYP/6-31G(d), E = Hartree, <S 2 > = S9

10 3 3a, UB3LYP/6-31G(d), E = Hartree S10

11 anti-5a, RB3LYP/6-31G(d), E = Hartree S11

12 anti- 3 5a, UB3LYP/6-31G(d), E = Hartree S12

13 syn-5a, RB3LYP/6-31G(d), E = Hartree S13

14 TS[3a anti-5a] -BS, UB3LYP/6-31G(d), E = Hartree, <S 2 > = S14

15 TS[3a syn-5a] -RS, RB3LYP/6-31G(d), E = Hartree S15

16 TS[ 3 3a anti- 3 5a], UB3LYP/6-31G(d), E = Hartree S16

17 3a, C 1 S 1 /S 0 conical intersection, CASSCF(2,2)/6-31G(d), E = Hartree C C C C C C C C C C C C C C C C C C C C C C C C C H H H H H H H H H H C H H C H C H H H S17