Supporting Information for. Unveiling the Role of Base and Additive in the Ullmann-type of Arene-Aryl C- C Coupling Reaction

Transcription

1 S1 Supporting Information for Unveiling the Role of Base and Additive in the Ullmann-type of Arene-Aryl C- C Coupling Reaction Manjaly J. Ajitha, a Fathima Pary, b Toby L. Nelson b, *, and Djamaladdin G. Musaev a, * a Cherry L. Emerson Center for Scientific Computation, Emory University, 1515 Dickey Drive, Atlanta, Georgia b Department of Chemistry, klahoma State University, 107 Physical Science, Stillwater, klahoma * s: dmusaev@emory.edu and toby.nelson@okstate.edu

2 S2 1. Interaction of complex 1 with K 3P 4 and Ag 2C 3, and ArI 2. Catalyst activation by Ag 2C 3 additive Page S3 Page S3 3. The Ar I activation first pathway; xidative addition of ArI followed by Page S4 deprotonation of the substrate by K 3P 4 4. The Ar I activation first pathway; xidative addition of ArI followed by Page S5 deprotonation of the substrate by Ag 2C 3 5. The substrate C-H activation first pathway by Ag 2C 3 Page S6 6. Various mechanistic consideration of ArI activation Page S6 7. Free energy surfaces of the base (i.e. K 3P 4) assisted PhI Activation and C-C Page S9 coupling. 8. Free energy surfaces of the additive (i.e. Ag 2C 3) assisted PhI Activation and Page S10 C-C coupling. 9. Catalyst regeneration Page S Regioselectivity studies Page S Cartesian coordinates (Å) of the optimized geometries Page S12

3 S3 1. Interaction of complex 1 with K 3P 4 and Ag 2C 3, and ArI K 3 P 4 N N I Cu K P K 2a -30.2/-17.2 K N N Cu 1 I Ag 2 C 3 N Cu N 2b -34.3/-21.5 I Ag Ag C ArI Ar N Cu N 2c -12.4/-1.1 I I Figure S1. Intermediates 2a, 2b and 2c formed by interaction of 1 with K3P4, Ag2C3, and ArI, respectively. ΔH/ΔG are in kcal/mol. Bond distances are in Å. 2. Catalyst activation by Ag 2C 3 additive N 1 N 2 Cu I Ag 2 C 3 (N 2,Cu,N 1,I) = deg. N 1 N 2 Cu I Ag 1 Cu N 1 = Cu N 2 = (Phen)CuI, (1) ΔH/ΔG = 0.0/0.0 Cu N 1 = Cu N 2 = Cu 1 = Ag 2 Ag 1 1 = /-21.5 [(Phen)CuI][Ag 2 C 3 ], (2b) I Ag-I (in free AgI) = Å N 1 Ag 1 (N 2,Cu,N 1,I) = deg. N Cu I Ag 1 N 2 Cu 1 Cu N 1 = Cu N 2 = 1.98 Ag 2 Cu 1 = Ag 1 1 = /-27.7 [(Phen)Cu(AgC 3 )][AgI], (3b) N 2 Cu N 1 = Cu N 2 = Ag 2 Cu 1 = Ag 1 1 = /-21.1 ν i = cm -1 [(Phen)CuI][Ag 2 C 3 ], TS1b Figure S2. Reactant, intermediate, transition state and product of the reaction of (Phen)CuI with Ag 2C 3. ΔH/ΔG are in kcal/mol. Bond distances are in Å.

4 S4 3. The Ar I activation first pathway; xidative addition of ArI followed by deprotonation of the substrate by K 3P 4 3a -30.7/ /0.0 N Cu N I K - P K + - K + +ArI% I K Ar I N K + Cu - N - P K + I N K + Cu - N - P K + S-4a S-TS2a S-5a -48.6/ / / / / /-8.6 Ar I K I K Ar I K N Cu N - P K + - +DBT% S-TS3a -44.2/ /12.8 Ar N Cu H N P - K +- S K I K I Figure S3a. Relative energies of Ar I activation first pathway assisted by K 3P 4 along with the geometries of reactants, intermediate, transition states involved in the process. ΔH/ΔG are in kcal/mol. Bond distances are in Å.

5 S5 4. The Ar I activation first pathway; xidative addition of ArI followed by deprotonation of the substrate by Ag 2C 3 3b -40.1/ /0.0 N Cu N I Ag C - Ag + +ArI% Ar I N I Ag Cu N - C Ag + Ar I N I Ag Cu N - C Ag + Ar N I Cu - N C S-4b S-TS2b S-5b / / / / / /12.7 Ag Ag + I +DBT% S-TS3b -42.4/ /23.9 Ar N S Cu H N C - I Ag Ag I Figure S3b. Relative energies of Ar I activation first pathway assisted by Ag 2C 3 along with the geometries of reactants, intermediate, transition states involved in the process. ΔH/ΔG are in kcal/mol. Bond distances are in Å.

6 S6 5. The substrate C-H activation first pathway by Ag 2C 3 Cu N 1 = Cu N 2 = Cu 1 = Cu C 1 = I Ag N 1 Cu N 2 1 ΔE/ΔH/ΔG=0.0/0.0/0.0 C 1 H [(Phen)Cu(AgC 3 )][AgI][DBT], (4b) Ag /-2.2 (from 3b) Cu N 1 = Cu N 2 = Cu 1 = Cu C 1 = C 1 H 1 = H 1 = I Cu N 1 N Ag 1 C 1 H Ag /11.9/12.4 [(Phen)Cu(AgC 3 )][AgI][DBT], (TS2b) Cu N 1 = Cu N 2 = Cu 1 = Cu C 1 = C N 1 H 1 Cu N Ag I Ag /13.5/12.8 [(Phen)Cu(AgC 2 H)][AgI][DBT ], (5b) Figure S4. PES of the substrate C-H activation first pathway by Ag 2C 3 along with the geometries of reactant, intermediate, transition state involved in the process. ΔH/ΔG are in kcal/mol. Bond distances are in Å. 6. Various mechanistic consideration of ArI activation The ArI addition to the (LL)Cu I (Nu) has been subject of several previous seminal investigations; following possible mechanisms were proposed as shown in Scheme S1: (i) Single electron transfer/iodine atom transfer (SET/IAT), (ii) Ar-I oxidative addition/c-x reductive elimination (A/RE), and (iii) σ-bond metathesis (SBM)

7 S7 SET + LLCu II (Nu) + I LLCu I (Nu) + I IAT A/RE I + LLCu II (Nu) I LLCu I (Nu) In the present work, Nu = DBT, LL = Phen SBM I LLCu I (Nu) Scheme S1. Various mechanistic senarios of the ArI addition to (Phen)Cu I (Nu). Here, we wish to emphasize that (Phen)Cu I (Nu) is (Phen)Cu I (DBT ) (5_1 in the manuscript text), which is less stable than its corresponding analogues, [(Phen)Cu][K 2P 3(H)(KI)](DBT ), 5a in the presence of base and [(Phen)Cu][AgC 2(H)(AgI)](DBT ), 5b in the presence of additive. Below we show the results of various ArI activation mechanisms with 5_1 followed by those with 5a and 5b respectively Stepwise and concerted SET mechanism: Marcus theory Concerted (ΔG r$ =$42.7$kcal/mol) LLCu I -Nu + + I LLCu II -Nu + + LLCu II -Nu + + I I Nu = DBT, LL = Phen Stepwise (ΔG r$ =$52.4$kcal/mol) According to Marcus theory, the activation barrier for ET can be calculated as: ΔG #$ = ΔG ( )1 + ΔG, 4ΔG (. (1) where ΔG, is the reaction energy, and ΔG ( is the intrinsic barrier (i.e. the activation energy at zero driving force) for the outer-sphere electron transfer. ΔG ( is related to the reorganization energy (λ) as: ΔG ( = λ (2) 4 According to the Marcus equation, the solvent reorganization energy λ ( can be calculated as: λ ( = (332kccal/mol) ; a < 2a = ) 1 1 ε BC ε. (3)

8 S8 where a < and a = are the solute radii and R is the sum of solute radii, ε BC is the optical dielectric constant, which is 2.05 and ε is the static dielectric constant which is for the DMF solvent (ε = 36.71). As there is no sufficient data to calculate the inner reorganization energy, it is neglected and hence total reorganization energy is same as that solvent reorganization energy. a < is calculated as 5.8 Å for 5 and 4.2 Å for ArI and therefore, λ is 16.0 kcal/mol. For the stepwise mechanism (Marcus-Hush theory), ΔG, is 52.4 kcal/mol and for the concerted mechanism (Saveant s model), ΔG, is 42.7 kcal/mol, which lead to significantly large barriers that are inaccessible at the present reaction conditions Iodine Atom transfer (IAT) Mechanism: The activation barrier of ArI via the IAT mechanism is estimated from the energies of the completely separated PhenCu II (DBT)I complex and the benzene radical. Transition state corresponding to the IAT was not be located after many attempts, while we found that this process is endergonic by about 28.0 kcal/mol and hence is not a favorable pathway xidative addition and SBM pathway of ArI activation on (Phen)Cu(DBT ), 5_1: The ArI coordination to 5_1 is favored by -13.7/-2.2 kcal/mol. However, this oxidative addition pathway requires a free energy of 24.7 kcal/mol. verall free energy activation barrier w.r.t 5a (stable species in the total PES) is 36.6 kcal/mol, which is very high. Moreover, the formed Cu(III) intermediate 5_3 is not stable. The free energy activation barrier for the SBM pathway (direct C-C coupling without formation of the Cu(III) intermediate is even higher (by 17.8 kcal/mol higher than that required for A pathway). Therefore, both A and SBM pathways originating from (Phen)Cu(DBT ), 5_1 are expected to be less favorable to the pathways discussed in the manuscript text. TS3 SBM' 27.4/40.3' I Ph N Cu N S Ph N Cu N TS3 A ' 8.7/22.5' I S N N Cu S 5_1' 0.0/0.0' 5_3' 8.1/21.4' Ph I N Cu N S ArI ' 5_2' (13.7/(2.2' Ph N Cu N I S Figure S5. PES of the oxidative addition and SBM pathways of ArI activation on (Phen)Cu(DBT ), 5_1. The geometries of reactant, intermediate and transition state involved in this process are also shown. ΔH/ΔG are in kcal/mol. Bond distances are in Å.

9 S9 We also considered the possibility of SET/IAT mechanism with the presence of base/additive along with (Phen)Cu I (Nu) species. The mechanisms similar to A/RE and SBM are already discussed in the manuscript text. Stepwise SET (Marcus-Hush theory) reaction: 5_a/b + ArI {[(Phen)Cu(Base/Additive)(DBT )]} + + [ArI]. Concerted SET (Saveant s model) reaction: 5_ a/b + ArI {[(Phen)Cu(Base/Additive)(DBT )]} + + I + Ar., IAT from ArI to the Cu I (nucleophile): 5_ a/b + ArI [(Phen)Cu(Base/Additive)(DBT )(I)] + Ar., We found that ΔG of e - transfer from 5_a/b to ArI (according to Marcus-Hush theory) is 19.5, and 41.3 kcal/mol for K 3P 4 and Ag 2C 3, respectively, whereas ΔG of e - transfer from 5_a/b to ArI along with ArI bond breaking (according to Saveant s model) is 9.9, and 31.7 kcal/mol for K 3P 4 and Ag 2C 3, respectively. Therefore, the activation barrier for such e - transfer is expected to be very high and rules out the possibility of such process in these types of reactions. ΔG of I transfer from ArI to 5_a/b is 5.2 and 29.0 kcal/mol for K 3P 4 and Ag 2C 3, respectively. Therefore, we conclude that both SET and IAT mechanism is not possible for the ArI activation. Moreover, the radical mechanism for the reaction of haloarenes with (LL)Cu(Nu) can be ruled out because of the invalidated negative radical clock experiments and lack of inhibition by radical scavengers. 7. Free energy surfaces of the base (i.e. K 3P 4) assisted PhI Activation and C-C coupling. ΔH/ΔG (in kcal/mol) TS4ac 40.7/ /34.5 TS3as 5_3ac 5_3ac 8.9/7.6 5_3as TS3as TS4ac 0.0/0.0 (-18.5/-8.8) 5_4as/5_4ac 5_3as -57.0/-55.4 (-75.5/-64.2) 5_4as/5_4ac Structures Figure S6. Free energy surfaces of the base (i.e. K 3P 4) assisted PhI Activation and C-C coupling.

10 S10 8. Free energy surfaces of the additive (i.e. Ag 2C 3) assisted PhI Activation and C-C coupling. ΔH/ΔG (in kcal/mol) 26.8/27.8 TS3bs TS3bs TS5bc_ox 15.2/18.0 TS5bc TS6bc 5_3bs (-18.5/-10.1) 0.0/0.0 5_3bs TS4bc_ox 1.3/3.1 TS4bc_ox 2.1/ /-6.2 5_3bc (-88.4/-79.7) -69.9/ _4bs/5_4bc 5_3bc TS4bc' Structures Figure S7. Free energy surfaces of the additive (i.e. Ag 2C 3) assisted PhI Activation and C-C coupling. 9. Catalyst regeneration The calculated energy for product dissociation from the complex 5_4bc is 19.4/5.0 kcal/mol. The resulted complex is the active catalyst 3b, geometrical features of which are discussed above. Even though, the substrate (DBT) coordination to 3b is exergonic by 2.2 kcal/mol, the total activation free energy barrier for the following C-H deprotonation is calculated to be 15.2 kcal/mol. It should be noted that the substitution of AgC 3(AgI) moiety in 3b by K 2P 4(KI) to form 3a requires 14.5 kcal/mol. However, the coordination of substrate to 3a is exergonic by 4.3 kcal/mol and the activation free energy barrier for the C-H deprotonation is negligible compared to the substitution free energy. verall, the C-H deprotonation in the second catalytic cycle requires approximately 15.0 kcal/mol free energy barrier for the substrate C- H deprotonation irrespective of K 2P 4 or AgC3 acting as the deprotonating ligand.

11 S11 (Phen)Cu[AgC 3 (AgI)] (3b) 19.4/5.0 5_4bc 0.0/0.0 (Phen)Cu[K 2 P 4 (KI)] (3a) 2.8/14.5 Figure S8. Structures involved in the dissociation of C-C coupled product from 5_4bc. ΔH/ΔG are in kcal/mol. Bond distances are in Å. 10. Regioselectivity studies 0.28 H H S 0.27 H H 0.27 N Cu N TS2a*& 13.2/12.3& K2P4(KI) 1& H 2& S TS2a& 0.7/0.8& K 2P 4(KI) N H Cu 1& N S 2& 4a& 0.0/0.0& 5a& 0.8/0.3& Figure S9. Regioselective C-H activation: The geometry (in Å) of the transition states, NB charges (in e ) and relative energies (in kcal/mol). We found that the deprotonation of the substrate at C1, i.e. the methylene site adjacent to the sulphonyl group (via TS2) is 11.5 kcal/mol more favorable than the deprotonation of the substrate at C2, i.e. the methylene site away from the sulphonyl group (TS2*). It is due to higher acidic nature of C1-H bond (calculated pka is 38.3) than C2-H bond (calculated pka is 46.9); NB charges indicate that C1-H is the most polarized C-H bond of the substrate, which could be easily activated than others.

12 S Cartesian coordinates (Å) of the optimized geometries Substrate (DBT) SCF Energy = a.u Number of imaginary frequencies= 0 ArI SCF Energy = a.u

13 S Number of imaginary frequencies= 0 K 3P 4 SCF Energy = a.u Number of imaginary frequencies= 0 Ag 2C 3 SCF Energy = a.u Number of imaginary frequencies= 0 (Phen)CuI SCF Energy = a.u

14 S Number of imaginary frequencies= 0 2a SCF Energy = a.u

15 S Number of imaginary frequencies= 0 TS1a SCF Energy = a.u

16 S Number of imaginary frequencies= 1 3a SCF Energy = a.u

17 S Number of imaginary frequencies= 0 4a SCF Energy = a.u

18 S Number of imaginary frequencies= 0 TS2a SCF Energy = a.u

19 S Number of imaginary frequencies= 1

20 S20 5a SCF Energy = a.u

21 S Number of imaginary frequencies= 0 5_1 SCF Energy = a.u

22 S Number of imaginary frequencies= 0 [K 2P 3(H)(KI)] SCF Energy = a.u Number of imaginary frequencies= 0

23 S23 5_2as SCF Energy = a.u

24 S Number of imaginary frequencies= 0 5_3as SCF Energy = a.u

25 S

26 S26 Number of imaginary frequencies= 0 5_2bs SCF Energy = a.u

27 S Number of imaginary frequencies= 0 5_3bs SCF Energy = a.u

28 S Number of imaginary frequencies= 0

29 S29 5_3ac SCF Energy = a.u

30 S Number of imaginary frequencies= 0 5_3bc SCF Energy = a.u

31 S

32 S Number of imaginary frequencies= 0 TS3as SCF Energy = a.u

33 S Number of imaginary frequencies= 1 TS3ac SCF Energy = a.u

34 S

35 S Number of imaginary frequencies= 1 5_4as/5_4ac SCF Energy = a.u

36 S