Carboxylate-assisted C–H activation of phenylpyridines with copper, palladium and ruthenium: a mass spectrometry and DFT study

The transition state of metal carboxylate mediated C–H activation is associated with carbon–metal bond formation supported by electron-poor carboxylates.


S3
In order to better understand the behavior of the reaction mixture for Ru(II) catalysis we have studied the dependence of the 2-phenylpyridine concentration on the formation of ions in the gas phase. The results are shown in Figure S4. For the sake of simplicity we kept the concentration of the catalytic solution the same in all of the solutions tested (10 -3 M, where the ruthenium dimer, acid and the base were mixed in 1:1:1 ratio), and only varied the amount of 2-PhPy.

Hammett studies
We decided to use plateau intensities, and the branching ratio between acid and 2-PhPy losses as a function of the σ constant, for the final interpretation of the results as the latter approach showed the highest accuracy interpretation of the results.  The branching ratio was determined from the fitted CID curves (Figures S16-S24).     -benzoic acid S12 Figure S24. The breakdown curve for the mass selected peak at m/z 509 (4-aminobenzoic acid derivative).

Benzoic Acid and 4-NitroBenzoic Acid DFT Study
The calculated potential energy surfaces with benzoate and 4-nitrobenzoate counter ions in place of acetate for all three of the catalytic processes previously shown. Equivalent structures were located and each of the reactions appears likely to proceed in the same manner as previously observed with the acetate counter ion. Structures are thus labelled in the same format. Calculations were performed with the B3LYP method and D2 empirical dispersion along with the 6-31G* (O, N, C, H) and SDD (Ru, Cu, Pd) basis sets. -4-aminobenzoic acid S13 Figure S25. Zero point potential energy surface (B3LYP/6-31G*:SDD(Ru)) for the Ru assisted C-H activation of 2-PhPy with a C 6 H 5 COO counter ion. Representations of structures are shown in Figure 2. All distances are in Å. Figure S26. Zero point potential energy surface (B3LYP/6-31G*:SDD(Ru)) for the Ru assisted C-H activation of 2-PhPy with a NO 2 C 6 H 4 COO counter ion. Representations of structures are shown in Figure  2. All distances are in Å. Figure S27. Zero point potential energy surface (B3LYP/6-31G*:SDD(Cu)) for the Cu assisted C-H activation of 2-PhPy with a C 6 H 5 COO counter ion. Representations of structures are shown in Figure 2. All distances are in Å. Figure S28. Zero point potential energy surface (B3LYP/6-31G*:SDD(Cu)) for the Cu assisted C-H activation of 2-PhPy with a NO 2 C 6 H 4 COO counter ion. Representations of structures are shown in Figure  2. All distances are in Å. Figure S29. Zero point potential energy surface (B3LYP/6-31G*:SDD(Pd)) for the Pd assisted C-H activation of 2-PhPy with a C 6 H 5 COO counter ion. Representations of structures are shown in Figure 2. All distances are in Å. Figure S30. Zero point potential energy surface (B3LYP/6-31G*:SDD(Pd)) for the Pd assisted C-H activation of 2-PhPy with a NO 2 C 6 H 4 COO counter ion. Representations of structures are shown in Figure  2. All distances are in Å.

Trifluoroacetic acid DFT study
We have calculated corresponding TS bond lengths and potential energy surfaces with a trifluoroacetate counter ion in place of acetate for all three of the catalytic processes previously shown. Equivalent structures were located and each of the reactions appears likely to proceed in the same manner as previously observed with the acetate counter ion. Structures are thus labelled in the same format. Calculations were performed in the same fashion as with an acetate counter ion. All distances are in Å. Figure S33. Zero point potential energy surface (B3LYP/cc-pVTZ:cc-pVTZ-pp(Cu)) for the Cu assisted C-H activation of 2-PhPy with a CF 3 COO counter ion. Representations of structures are shown in Figure 2.

S21
All distances are in Å. Figure S34. Zero point potential energy surface (B3LYP/cc-pVTZ:cc-pVTZ-pp(Pd)) for the Pd assisted C-H activation of 2-PhPy with a CF 3 COO counter ion. Representations of structures are shown in Figure 2.

S22
All distances are in Å.