Bond Cleavage with Iridium Porphyrin Complexes

Transcription

1 Competitive Aryl-luorine and Aryl-Halogen (Halogen = Cl, Br) Bond Cleavage with Iridium Porphyrin Complexes Ying Ying Qian, Bao Zhu Li, and Kin Shing Chan* Department of Chemistry, The Chinese University of Hong Kong, Shatin, ew Territories, Hong Kong, People s Republic of China ksc@cuhk.edu.hk. Supporting Information Contents: S1. urther Experimental Supports to Main Manuscript S2 S2. Experimental Procedures S9 S3. 1 H, 13 C and 19 MR Spectra of Iridium Porphyrin Aryls S16 S4. References S20 1

2 S1. urther Experimental Supports to Main Manuscript S1.1 Base-Promoting Effect in Ar- Bond Cleavage Reactions Ir(ttp)SiEt 3 1b was found to be thermally stable in the presence of 1,4-difluorobenzene without the addition of KOH (eq S1). C Ir(ttp)SiEt H 6 2, 200 o Ir(ttp) C, 3 d 1b 100 equiv 3b Recovery 96% o aromatic CA product 3b observed (S1) S1.2 Mechanistic Possibilities for Ar- Bond Cleavage The CA reaction likely operates through an addition-elimination process (S Ar, Scheme S1, pathway i), but not via an elimination-addition process (benzyne mechanism, Scheme S1, pathway ii). The supporting evidence for the addition-elimination process comes from the selective CA for 1,3-difluorobenzene. Scheme S1 shows the proposed processes for the reaction between Ir(ttp) - and 1,3-difluorobenzene. Since no Ir(ttp)(4--C 6 H 4 ) was observed during the reaction, the benzyne mechanism was unlikely (eq S2). Ir(ttp)SiEt equiv KOH 2, dark, 200 o C, 4 d Ir(ttp) 80% yield (S2) Scheme S1. Possible Processes for the Aromatic CA Reaction of 1,3-Difluorobenzene and Ir(ttp) - (pathway i: Addition-Elimination, pathway ii: Elimination-Addition) 2

3 pathway i Ir(ttp) Ir(ttp) Ir(ttp) - + pathway ii Ir(ttp) + Ir(ttp) 3

4 S1.3 Reaction Profile for Ir(ttp)SiEt 3 and KOH in Benzene-d 6 Ir(ttp)SiEt 3 + KOH 11% Remained 200 o C Ir(ttp) 5 d, Benzene-d - K + + SiEt 3 OK + (SiEt 3 ) 2 O + H 2 O 6 11% 20% 3% (S2) t=24d (SiEt 3 ) 2 O t=12d 1b t=5d SiEt 3 OK t=2d t=0 1a igure S1. 1 H MR Spectra for the Reaction of Ir(ttp)SiEt 3 and KOH 100 Yield / % Ir(ttp)SiEt 3 KOSiEt 3 Ir(ttp)SiEt 3 Ir(ttp) - K + Ir(ttp)H Unknown KOSiEt 3 O(SiEt 3 ) 2 20 O(SiEt 3 ) 2 Ir(ttp) - K + 0 Ir(ttp)H 0 5 Unknown Time / d igure S2. Time Profile for the Reaction of Ir(ttp)SiEt 3 1a and KOH 4

5 Table S1. Time Profile for the Reaction of Ir(ttp)SiEt 3 1a and KOH Time / d Yield / % Ir(ttp)SiEt 3 Ir(ttp) - Unknown Ir(ttp)H (Et 3 Si) 2 O KOSiEt

6 1 H MR of HSiEt 3 (Standard) 1 H MR of HOSiEt 3 (Standard) 6

7 1 H MR of O(SiEt 3 ) 2 (Standard) 1 H MR of reaction of Ir(ttp)SiEt 3 with KOH for 5 days 7

8 1 H MR of reaction of Ir(ttp)SiEt 3 with KOH for 24 days 1 H MR for comparison of various triethyl silyl compounds Ir(ttp)SiEt 3 + KOH d O(SiEt 3 ) 2 Ir(ttp)SiEt 3 + KOH d Et 3 SiOK HSiEt 3 O(SiEt 3 ) 2 HOSiEt ppm (f1)

9 S2. Experimental Procedures Unless otherwise noted, all chemicals were obtained from commercial suppliers and used without further purification. Hexane for chromatography was distilled from anhydrous calcium chloride. Benzene and TH used as solvent were distilled from sodium. Thin-layer chromatography was performed on precoated silica gel plates for thin-layer analyses for the reaction mixture. All preparation reactions were carried out in a teflon screw-head stoppered tube in 2. or purification of iridium aryl complexes, fresh column chromatography was used and carried out in air using alumina (90 active neutral, mesh). Ir(ttp)(CO)Cl 1 1a, Ir(ttp)SiEt 3 2 1b, [Ir(ttp) - a + ] 3 1c, Ir(ttp)H 1a 1d, Ir 2 (ttp) 2 4 1e were prepared according to the literatures. 1 H MR spectra were recorded on a Bruker AV400 (400 MHz). Chemical shifts were reported with reference to the residual solvent protons in C 6 D 6 (δ 7.15 ppm) or in CDCl 3 (δ 7.26 ppm) as the internal standard. Coupling constants (J) are reported in hertz (Hz). 13 C MR spectra were recorded on a Bruker 400 (100 MHz) spectrometer and referenced to CDCl 3 (δ 77.1 ppm). 19 MR spectra were recorded on a Varian XL-400 spectrometer at 376 MHz. Chemical shifts were referenced with the external standard fluorine in C 6 H 5 C 3 using a sealed melting point tube and put into the MR tube (δ = 0.00 ppm). Chemical shifts (δ) were reported as part per million (ppm) in (δ) scale downfield from C 7 H Coupling constants (J) were reported in Hertz (Hz). High-resolution mass spectra (HRMS) were performed on a Thermofinnign MAT 95 XL in AB (using 3-nitrobenzyl alcohol (BA) matrix and CH 2 Cl 2 as the solvent) and ESI model (MeOH:CH 2 Cl 2 = 1:1 as the solvent). 9

10 Reaction between Ir(ttp)(CO)Cl (1a) and 4-fluorochlorobenzene (2a) with 10 equiv K 2 CO 3 at 150 o C for 2 d in benzene solvent. Ir(ttp)(CO)Cl (10.0 mg, mmol), K 2 CO 3 (14.9 mg, 0.11 mmol, 10 equiv) and 4-fluorochlorobenzene (0.24 ml, 200 equiv) were added in benzene (1.0 ml). The mixture was degassed for three freeze-thaw-pump cycles, purged with 2 and heated at 150 o C for 2 days. Excess benzene was removed by vacuum distillation. The brown residue was purified by column chromatography on alumina eluting with a mixture of hexane/ch 2 Cl 2 (2:1). A purple solid of Ir(ttp)(4-fluorophenyl) (3b) 6 (6.2 mg, mmol, 60%) was isolated. Reaction between Ir(ttp)(CO)Cl (1a) and 4-fluorochlorobenzene (2a) with 10 equiv KOH at 150 o C for 5 h in benzene solvent. Ir(ttp)(CO)Cl (10.0 mg, mmol), KOH (6.2 mg, 0.11 mmol, 10 equiv) and 4-fluorochlorobenzene (0.24 ml, 200 equiv) were added in benzene (1.0 ml). The mixture was degassed for three freeze-thaw-pump cycles, purged with 2 and heated at 150 o C for 5 hours. Excess benzene was removed by vacuum distillation. The brown residue was purified by column chromatography on alumina eluting with a mixture of hexane/ch 2 Cl 2 (2:1). Purple solid of Ir(ttp)(4-fluorophenyl) (3b) 6 (5.2 mg, mmol, 50%) and Ir(ttp)(4-chlorophenyl) 6 (3a) (5.3 mg, mmol, 50%) were isolated. Reaction between Ir(ttp)(CO)Cl (1a) and 4-fluorochlorobenzene (2a) with 10 equiv KOH at 150 o C for 18 h in TH solvent. Ir(ttp)(CO)Cl (10.0 mg, mmol), KOH (6.2 mg, 0.11 mmol, 10 equiv) and 4-fluorochlorobenzene (0.24 ml, 200 equiv) were added in TH (1.0 ml). The mixture was degassed for three freeze-thaw-pump cycles, purged with 2 and heated at 150 o C for 18 hours. Excess TH was removed 10

11 by vacuum distillation. The brown residue was purified by column chromatography on alumina eluting with a mixture of hexane/ch 2 Cl 2 (2:1). Purple solid of Ir(ttp)(4-fluorophenyl) (3b) 6 (2.5 mg, mmol, 24%) and Ir(ttp)(4-chlorophenyl) 6 (3a) (7.9 mg, mmol, 75%) were isolated. Reaction between Ir(ttp)(CO)Cl (1a) and 4-fluorochlorobenzene (2a) with 10 equiv KOH at 120 o C for 24 h in TH solvent. Ir(ttp)(CO)Cl (10.0 mg, mmol), KOH (6.2 mg, 0.11 mmol, 10 equiv) and 4-fluorochlorobenzene (0.24 ml, 200 equiv) were added in TH (1.0 ml). The mixture was degassed for three freeze-thaw-pump cycles, purged with 2 and heated at 120 o C for 24 hours. Excess TH was removed by vacuum distillation. The brown residue was purified by column chromatography on alumina eluting with a mixture of hexane/ch 2 Cl 2 (2:1). Purple solid of Ir(ttp)(4-fluorophenyl) (3b) 6 (1.3 mg, mmol, 13%) and Ir(ttp)(4-chlorophenyl) (3a) 6 (8.9 mg, mmol, 85%) were isolated. Reaction between Ir(ttp)SiEt 3 (1b) and 4-fluorochlorobenzene (2a) with 10 equiv KOH at 120 o C for 24 h in TH solvent. Ir(ttp)SiEt 3 (10.0 mg, mmol), KOH (6.2 mg, 0.11 mmol, 10 equiv) and 4-fluorochlorobenzene (0.24 ml, 200 equiv) were added in TH (1.0 ml). The mixture was degassed for three freeze-thaw-pump cycles, purged with 2 and heated at 120 o C for 24 hours. Excess TH was removed by vacuum distillation. The brown residue was purified by column chromatography on alumina eluting with a mixture of hexane/ch 2 Cl 2 (2:1). Purple solid of Ir(ttp)(4-fluorophenyl) (3b) 6 (trace, <5%) and Ir(ttp)(4-chlorophenyl) (3a) 6 (9.5 mg, mmol, 90%) were isolated. 11

12 Reaction between Ir(ttp)(CO)Cl (1a) and 1-bromo-4-fluorobenzene (2b) with 10 equiv KOH at 200 o C for 6 h in benzene solvent. Ir(ttp)(CO)Cl (10.0 mg, mmol), KOH (6.2 mg, 0.11 mmol, 10 equiv) and 1-bromo-4-fluorobenzene (0.15 ml, 100 equiv) were added in benzene (1.0 ml). The mixture was degassed for three freeze-thaw-pump cycles, purged with 2 and heated at 200 o C for 6 hours. Excess benzene was removed by vacuum distillation. The brown residue was purified by column chromatography on alumina eluting with a mixture of hexane/ch 2 Cl 2 (2:1). Purple solid of Ir(ttp)(4-fluorophenyl) (3b) 6 (9.3 mg, mmol, 90%) was isolated. Reaction between Ir(ttp)(CO)Cl (1a) and 1-bromo-4-fluorobenzene (2b) with 10 equiv KOH at 200 o C for 6 h in TH solvent. Ir(ttp)(CO)Cl (10.0 mg, mmol), KOH (6.2 mg, 0.11 mmol, 10 equiv) and 1-bromo-4-fluorobenzene (0.15 ml, 100 equiv) were added in TH (1.0 ml). The mixture was degassed for three freeze-thaw-pump cycles, purged with 2 and heated at 200 o C for 6 hours. Excess TH was removed by vacuum distillation. The brown residue was purified by column chromatography on alumina eluting with a mixture of hexane/ch 2 Cl 2 (2:1). Purple solid of Ir(ttp)(4-fluorophenyl) (3b) 6 (7.2 mg, mmol, 70%) and Ir(ttp)(4-bromophenyl) (3c) 6 (trace, <5%) was isolated. Reaction between Ir(ttp)(CO)Cl (1a) and 1-bromo-4-fluorobenzene (2b) with 10 equiv KOH at 120 o C for 18 h in TH solvent. Ir(ttp)(CO)Cl (10.0 mg, mmol), KOH (6.2 mg, 0.11 mmol, 10 equiv) and 1-bromo-4-fluorobenzene (0.15 ml, 100 equiv) were added in TH (1.0 ml). The mixture was degassed for three freeze-thaw-pump cycles, purged with 2 and heated at 120 o C for 18 hours. Excess 12

13 TH was removed by vacuum distillation. The brown residue was purified by column chromatography on alumina eluting with a mixture of hexane/ch 2 Cl 2 (2:1). Purple solid of Ir(ttp)(4-fluorophenyl) (3b) 6 (6.8 mg, mmol, 66%) and Ir(ttp)(4-bromophenyl) (3c) 6 (2.2 mg, mmol, 20%) was isolated. Reaction between Ir(ttp)SiEt 3 (1b) and 1-bromo-4-fluorobenzene (2b) with 10 equiv KOH at 120 o C for 24 h in TH solvent. Ir(ttp)SiEt 3 (10.0 mg, mmol), KOH (6.2 mg, 0.11 mmol, 10 equiv) and 1-bromo-4-fluorobenzene (0.15 ml, 100 equiv) were added in TH (1.0 ml). The mixture was degassed for three freeze-thaw-pump cycles, purged with 2 and heated at 120 o C for 24 hours. Excess TH was removed by vacuum distillation. The brown residue was purified by column chromatography on alumina eluting with a mixture of hexane/ch 2 Cl 2 (2:1). Purple solid of Ir(ttp)(4-fluorophenyl) (3b) 6 (2.9 mg, mmol, 30%) and Ir(ttp)(4-bromophenyl) (3c) 6 (4.1 mg, mmol, 40%) was isolated. Reaction between Ir(ttp)(4-fluorophenyl) (3b) and 4-fluorochlorobenzene (2a) with 10 equiv KOH at 120 o C for 1 day in TH solvent. Ir(ttp)(4-fluorophenyl) (10.0 mg, mmol), KOH (6.2 mg, 0.11 mmol, 10 equiv) and 4-fluorochlorobenzene (0.24 ml, 200 equiv) were added in TH (1.0 ml). The mixture was degassed for three freeze-thaw-pump cycles, purged with 2 and heated at 120 o C for 1 day. Excess TH was removed by vacuum distillation. The brown residue was purified by column chromatography on alumina eluting with a mixture of hexane/ch 2 Cl 2 (2:1). Purple solid of Ir(ttp)(4-fluorophenyl) (3b) 6 (9.9 mg, mmol, 99%) was isolated. 13

14 Reaction between Ir(ttp)(4-chlorophenyl) (3a) and 4-fluorochlorobenzene (2a) with 10 equiv KOH at 150 o C for 2 days in benzene solvent. Ir(ttp)(4-chlorophenyl) (10.0 mg, mmol), KOH (6.2 mg, 0.11 mmol, 10 equiv) and 4-fluorochlorobenzene (0.24 ml, 200 equiv) were added in benzene (1.0 ml). The mixture was degassed for three freeze-thaw-pump cycles, purged with 2 and heated at 150 o C for 2 days. Excess benzene was removed by vacuum distillation. The brown residue was purified by column chromatography on alumina eluting with a mixture of hexane/ch 2 Cl 2 (2:1). Purple solid of Ir(ttp)(4-chlorophenyl) (3a) 6 (9.9 mg, mmol, 99%) was isolated. Reaction between Ir(ttp) - a + (1c) and luorobenzene (2c) without the Addition of KOH. luorobenzene (1.0 ml, 500 equiv) was added to Ir(ttp) - a + (18.6 mg, mmol) under 2, and the mixture was degassed for three freeze-pump-thaw. Then the mixture was heated at 120 o C for 2 days. The crude product was purified by column chromatography on alumina eluting with a mixture of hexane/ch 2 Cl 2 (2:1), and a purple solid of Ir(ttp)C 6 H 5 (3d) 6 (8.2 mg, mmol, 40%) was isolated. Reaction between Ir(ttp)H (1d) and luorobenzene (2c) without the Addition of KOH. luorobenzene (0.8 ml, 500 equiv) was added to Ir(ttp)H (15.4 mg, mmol), and the mixture was degassed for three freeze-pump-thaw. Then the mixture was heated at 200 o C for 4 days. The crude product was purified by column chromatography on alumina eluting with a mixture of hexane/ch 2 Cl 2 (1:1), and a purple solid mixture of unknowns (4.3 mg, ca 28 %) was isolated. o aromatic CA or CHA product was observed. 14

15 Reaction of Ir 2 (ttp) 2 (1e) and luorobenzene (2c) without the Addition of KOH. luorobenzene (1.0 ml, 1000 equiv) was added to Ir 2 (ttp) 2 (18.2 mg, mmol), and the mixture was degassed for three freeze-pump-thaw. Then the mixture was heated at 200 o C for 2 days. The crude product was purified by column chromatography on alumina eluting with a mixture of hexane/ch 2 Cl 2 (1:1), and a purple solid mixture of unknowns (11.8 mg, ca 65 %) was isolated. And no aromatic CA or CHA product was observed. Reaction between Ir(ttp)SiEt 3 (1b) with KOH in Benzene-d 6 in a Sealed-MR Tube. Benzene-d 6 (0.5 ml) was added to a mixture of Ir(ttp)SiEt 3 (9.3 mg, mmol) and KOH (5.3 mg, mmol, 10 equiv) in an MR tube with a rotaflo stopper and degassed for three freeze-pump-thaw. The mixture was frozen under liquid nitrogen and then flame-sealed under vacuum. The sealed-mr tube was heated at 200 o C, and monitored by 1 H MR spectroscopy and the yield of product was calibrated with the internal standard residual benzene in benzene-d 6. 15

16 S3. 1 H, 13 C and 19 MR Spectra of Iridium Porphyrin Aryls o List of Spectra Page H MR of Ir(ttp)phenyl (3d) S16 1 H MR of Ir(ttp)(4-fluorophenyl) (3b) S16 13 C MR of Ir(ttp)( 4-fluorophenyl) (3b) S17 19 MR of Ir(ttp)( 4-fluorophenyl) (3b) S17 1 H MR of Ir(ttp)(4-chlorophenyl) (3a) S18 1 H MR of Ir(ttp)(4-bromophenyl) (3c) S18 16

17 1 H MR of Ir(ttp)phenyl (3d) Ir 1 H MR of Ir(ttp)(4-fluorophenyl) (3b) Ir 17

18 13 C MR of Ir(ttp) (4-fluorophenyl) (3b) Ir 19 MR of Ir(ttp)(4-fluorophenyl) (3b) Ir 18

19 1 H MR of Ir(ttp)(4-chlorophenyl) (3a) Cl Ir 1 H MR of Ir(ttp)(4-bromophenyl) (3c) Br Ir 19

20 S4. References 1. (a) Yeung, S. K.; Chan, K. S. Organometallics 2005, 24, (b) Yeung, S. K. Ph. D. Thesis, The Chinese University of Hong Kong, (c) van der Ent, A.; Onderdelinden, A. L. Inorg. Synth. 1973, 14, Li, B. Z.; Chan, K. S. Organometallics 2008, 27, Tse, A. K.-S.; Wu, B.-M.; Mak, T. C. W.; Chan, K. S. J. Organomet. Chem. 1998, 568, Chan, K. S.; Leung, Y. -B. Inorg. Chem. 1994, 33, Mooney, E.. An introduction to 19 MR spectroscopy; Heyden, in co-operation with Sadtler Research Laboratories, Cheung, C. W.; Chan, K. S. Organometallics 2011, 30,