Supporting Information One Pot Synthesis of 1,3- Bis(phosphinomethyl)arene PCP/PNP Pincer Ligands and Their Nickel Complexes Wei-Chun Shih and Oleg V. Ozerov* Department of Chemistry, Texas A&M University, College Station, Texas 77842 ozerov@chem.tamu.edu S1
Table of Contents. I. General procedure for screening and optimization of synthesis of 3a-X2 S3 II. Synthesis of tbu (PCP)H by different methods III. C-P Bond cleavage observation in Ph (PCP)H and ipr (PNP) synthesis IV. Control reactions related to the synthesis of ipr (PCP)NiX (6) S4 S6 S8 V. NMR spectra S10 S2
I. General procedure for screening and optimization of synthesis of 3a-X2 Table 1, Entry 1~6: In a J. Young NMR tube, the reactin of 1-X (0.20 mmol, 23.0 μl for 1-Cl, 24.0 μl for 1-Br, and 43.6 mg for 1-I) and 2a-X (0.20 mmol, 38.0 μl for 2a-Cl and 54.4 mg for 2a-I) in 0.7 ml of C6D6 (Entry 1) or CD3CN (Entry 2~6) was heated at the required temperature as indicated in Table 1 for 15 h. After the reaction was cooled to room temperature, the conversion was determined by 31 P NMR and 1 H NMR. Table 1, Entry 7~10: In a J. Young NMR tube, to the CD3CN (0.7 ml) solution of 1-Cl (23.0 μl, 0.20 mmol) and 2a-Cl (38.0 μl, 0.20 mmol) was added sodium iodide (30.0 mg, 0.20 mmol for Entry 7; 60.0 mg, 0.40 mmol for Entry 8; 3.00 mg, 0.02 mmol for Entry 9) or lithium bromide (17.4 mg, 0.20 mmol for Entry 10). The mixture was heated at 50 C for 15 h (Entry 7, 8, and 10) or 20 h (Entry 9). After the reaction was cooled to room temperature, the conversion was determined by 31 P NMR and 1 H NMR. S3
II. Synthesis of tbu (PCP)H by different methods In a screw-cap culture tube, to the acetonitrile solution (10 ml) of m-xylylene dibromide (4a-Br2, 528 mg, 2.00 mmol) was added di-tert-butylchlorophosphine (2a-Cl, 723 mg, 4.00 mmol), and the reaction mixture was stirred at 100 C for 15 h. After cooling down to room temperature, magnesium powder (122 mg, 5.00 mmol) was added under argon, and the reaction mixture was stirred at 0 C for 2 h. The reaction was allowed to warm to room temperature and stirred overnight. The product was extracted by pentane (3 20 ml), and the volatiles were removed under vacuum, yielding a yellow oil. Isolated yield: 600 mg, 76% (75% purity). * * * * * * * * Impurity 31 P{ 1 H} NMR * Figure S1. 1 H NMR and 31 P{ 1 H} NMR spectra of 5b in C6D6 at RT measured on a 500 MHz Varian NMR spectrometer. S4
In a screw cap culture tube, to the acetonitrile solution (10 ml) of m-xylylene dichloride (4a-Cl2, 350 mg, 2.00 mmol) was added 2a-Cl (723 mg, 4.00 mmol) and sodium iodide (1.20g, 8.00 mmol), and the reaction mixture was stirred at 100 C for 15 h. After cooling down to room temperature, magnesium powder (97 mg, 4.00 mmol) was added under argon, and the reaction mixture was stirred at room temperature for 36 h. The product was extracted by pentane (3 20 ml), and the volatiles were removed under vacuum, yielding an off white solid. Isolated yield: 507 mg, 64%. 31 P{ 1 H} NMR *Et 2O from C 6D 6 * Figure S2. 1 H NMR and 31 P{ 1 H} NMR spectra of 5b in C6D6 at RT measured on a 500 MHz Varian NMR spectrometer. S5
III. C-P Bond cleavage observation in Ph (PCP)H and ipr (PNP) synthesis The benzyl C-P bond cleavage was observed in the synthesis of Ph (PCP)H (5d) and ipr (PNP) (5e), which gave rise to the formation of (3-methylbenzyl)diphenylphosphine (5d ) and 2- ((diisopropylphosphanyl)methyl)-6-methylpyridine (5e ) as side products. The following two 1 H NMR spectra showed the identification of these side products. In the synthesis of 5d, two small peaks were observed at 3.24 ppm and 2.02 ppm (Figure S3), which corresponded to the benzylic protons and methyl protons of 5d. * * Figure S3. 1 H NMR spectrum of 5d and 5d in C6D6 at RT measured on a 500 MHz Varian NMR spectrometer. S6
Analogously, in the synthesis of 5e, two small peaks were observed at 2.99 ppm (d, JH-P = 1.5 Hz) and 2.40 ppm (s) (Figure S4), which corresponded to the benzylic protons and methyl protons of 5e. * * Figure S4. 1 H NMR spectrum of 5e and 5e in C6D6 at RT measured on a 500 MHz Varian NMR spectrometer. S7
IV. Control reactions related to the synthesis of ipr (PCP)NiX (6) Reaction of di-iso-propylchlorophosphine (2b-Cl) with nickel powder. In a screw cap culture tube, to the CD3CN solution (2 ml) of 2b-Cl (61 mg, 0.40 mmol) was added nickel powder (29 mg, 0.50 mmol). The reaction mixture was stirred at 100 C for 15 h. After cooling down to room temperature, the mixture was filtered through a pad of Celite. The filtrate was analyzed by 1 H NMR and 31 P NMR spectroscopy, showing only unreacted 2b-Cl was present. Reaction of xylylene dibromide (4a-Br2) with nickel powder. In a screw cap culture tube, to the CD3CN solution (2 ml) of 4a-Br2 (53 mg, 0.20 mmol) was added nickel powder (29 mg, 0.50 mmol). The reaction mixture was stirred at 100 C for 15 h. After cooling down to room temperature, the mixture was filtered through a pad of Celite. The filtrate was analyzed by 1 H NMR spectroscopy, showing 72% of unreacted 4a-Br2 along with new resonances attributable to compounds containing Ar-CH2CH2-Ar linkages from the likely benzyl-benzyl coupling (Figure S5). S8
* Δ Δ * * Δ Δ Figure S5. 1 H NMR spectrum of the mixture resulting after treatment of 4a-Br2, with Ni powder in CD3CN at 100 C for 15 h. The spectrum was measured at ambient temperature on a 500 MHz Varian NMR spectrometer. Signals corresponding to 4a-Br2 (72% unreacted) and to tentatively assigned products highlighted. S9
V. NMR spectra. isomer * Figure S6. 1 H NMR spectrum of 3a-BrCl in CD3CN at RT measured on a 500 MHz Varian NMR Spectrometer. S10
Figure S7. 13 C NMR spectrum of 3a-BrCl in CD3CN at RT measured on a 500 MHz Varian NMR Spectrometer. S11
Figure S8. 1 H NMR spectrum of 3b-BrCl in CD3CN at RT measured on a 500 MHz Varian NMR Spectrometer. S12
Figure S9. 13 C NMR spectrum of 3b-BrCl in CD3CN at RT measured on a 500 MHz Varian NMR Spectrometer. S13
Figure S10. 1 H NMR spectrum of 3a in CDCl3 at RT measured on a 500 MHz Varian NMR Spectrometer. S14
Figure S11. 13 C NMR spectrum of 3a in CDCl3 at RT measured on a 500 MHz Varian NMR Spectrometer. S15
Figure S12. 1 H NMR spectrum of 3b in CD2Cl2 at RT measured on a 500 MHz Varian NMR Spectrometer. S16
Figure S13. 13 C NMR spectrum of 3b in CD2Cl2 at RT measured on a 500 MHz Varian NMR Spectrometer. S17
Figure S14. 1 H NMR spectrum of 5a in C6D6 at RT measured on a 300 MHz Varian NMR Spectrometer. S18
Figure S15. 13 C NMR spectrum of 5a in C6D6 at RT measured on a 500 MHz Varian NMR Spectrometer. S19
Figure S16. 1 H NMR spectrum of 5b in C6D6 at RT measured on a 500 MHz Varian NMR Spectrometer. S20
Figure S17. 13 C NMR spectrum of 5b in C6D6 at RT measured on a 500 MHz Varian NMR Spectrometer. S21
Figure S18. 1 H NMR spectrum of 5c in C6D6 at RT measured on a 500 MHz Varian NMR Spectrometer. S22
Figure S19. 13 C NMR spectrum of 5c in C6D6 at RT measured on a 500 MHz Varian NMR Spectrometer. S23
*Et 2O from C 6D 6 * * Figure S20. 1 H NMR spectrum of 5d in C6D6 at RT measured on a 500 MHz Varian NMR Spectrometer. S24
Figure S21. 13 C NMR spectrum of 5d in C6D6 at RT measured on a 500 MHz Varian NMR Spectrometer. S25
*5e * * Figure S22. 1 H NMR spectrum of 5e in CDCl3 at RT measured on a 500 MHz Varian NMR Spectrometer. S26
Figure S23. 13 C NMR spectrum of 5e in CDCl3 at RT measured on a 500 MHz Varian NMR Spectrometer. S27
* 6-Br * 6-Cl Figure S24. 31 P NMR spectrum of mixture of 6-Cl and 6-Br in CD2Cl2 at RT measured on a 500 MHz Varian NMR Spectrometer. S28
Figure S25. 31 P NMR spectrum of 6-Br in CD2Cl2 at RT measured on a 500 MHz Varian NMR Spectrometer. S29
Figure S26. 1 H NMR spectrum of 6-Br in CD2Cl2 at RT measured on a 500 MHz Varian NMR Spectrometer. S30
Figure S27. 13 C NMR spectrum of 6-Br in CD2Cl2 at RT measured on a 500 MHz Varian NMR Spectrometer. S31
*residual Et 2O, CH 2Cl 2 and pentane solvents * * * * Figure S28. 1 H NMR spectrum of 7 in CD3CN at RT measured on a 500 MHz Varian NMR Spectrometer. S32
Figure S29. 1 H NMR spectrum of 7 in CDCl3 at RT measured on a 500 MHz Varian NMR Spectrometer. S33
Figure S30. 13 C NMR spectrum of 7 in CDCl3 at RT measured on a 500 MHz Varian NMR Spectrometer. S34