Chapter 3: Access to Well-Defined Ruthenium(I) and Osmium(I) Metalloradicals
3.4 Experimental Section
3.4.6 Synthesis
Synthesis of [SiPiPr3]RuCl (3.1). H[SiPiPr3] (0.82 g, 1.3 mmol), [(C6H6)OsCl2]2 (0.44 g, 0.88 mmol), and Et3N (0.93 mL, 6.7 mmol) were charged into a 100 mL Schlenk tube and 25 mL of toluene was added. The flask was sealed, and heated at 90 oC for 18 h. The reaction mixture was filtered through Celite, and the volatiles were removed in vacuo to yield analytically pure material (0.95 g, 95%). 1H NMR (C6D6, δ): 8.26 (d, J = 7.2 Hz, 3H), 7.23-7.16 (m, 6H), 7.01 (t, J = 7.2 Hz, 3H), 2.44 (m, 6H), 1.19 (m, 18H), 0.97 (s, 18H). 13C{1H} NMR (CDCl3, δ): 156.0 (m), 144.8 (m), 132.4 (m), 129.6, 128.7, 126.8, 29.5 (m), 20.0, 19.9. 29Si{1H} NMR (CDCl3, δ): 75.5 (q, J = 16.7 Hz).31P{1H} NMR (C6D6, δ): 72.6 (s). Anal. Calcd for C36H54SiP3ClRu: C, 58.09; H, 7.31 Found: C, 58.43;
H, 6.99.
Synthesis of [SiPiPr3]OsCl (3.2). H[SiPiPr3] (0.50 g, 0.82 mmol) and [(C6H6)OsCl2]2
(0.36g, 0.53 mmol) were charged into a flask and toluene (50 mL) was added.
Triethylamine (0.50 mL, 2.5 mmol) was added and the flask was heated at 90 °C for 18 h.
The mixture was filtered through Celite, and the volatiles were removed in vacuo to yield analytically pure material (0.64g, 94%). 1H NMR (C6D6, δ): 8.29 (d, J = 6.9 Hz, 3H), 7.26-7.16 (m, 6H), 6.99 (t, J = 6.9 Hz, 3H), 2.62 (m, 6H), 1.19 (m, 18H), 1.00 (s, 18H).
13C{1H} NMR (CDCl3, δ): 156.9 (m), 146.3 (m), 132.6 (m), 130.0, 129.1, 127.1, 30.9 (m), 20.7, 20.4. 29Si{1H} NMR (CDCl3, δ): 53.5 (m).31P{1H} NMR (C6D6, δ): 45.2 (s). Anal.
Calcd for C36H54SiP3ClOs: C, 51.88; H, 6.52; N. 0.00. Found: C, 52.33; H, 6.68; N, <
0.05.
Synthesis of [SiPiPr3]RuN2 (3.3). [SiPiPr3]RuCl (0.10 g, 0.13 mmol) was suspended in 8 mL of Et2O in a scintillation vial and placed inside a cold well that was cooled in a dry ice/acetone bath. KC8 (20. Mg, 0.15 mmol) was added in one portion. The resulting mixture was stirred inside the cold well for 15 min The brown mixture was taken out of the well, and stirred for an additional 20 min at room temperature, at which time a color change to dark green resulted. Volatiles were removed, and the product was extracted with benzene and filtered through Celite. Lyophilization of the benzene solution resulted in 0.18 g (91%) of green 3.3. Crystals suitable for X-ray diffraction were obtained through slow evaporation of a concentrated pentane solution. 1H NMR (C6D6, δ): 10.1, 8.7, 7.8, 3.1, 1.0. IR (KBr, cm-1): 2088 (ν[N2]). eff (SQUID) = 1.69 μB.
Synthesis of [SiPiPr3]OsN2 (3.4). [SiPiPr3]OsCl (0.10 g, 0.12 mmol) was suspended in 8 mL Et2O in a scintillation vial and placed inside a cold well that was cooled in a dry ice/acetone bath. KC8 (21 mg, 0.15 mmol) was added in one portion and the mixture was stirred for 15 min inside the cold well. The mixture was stirred for an additional 20 min at room temperature. Volatiles were removed, and benzene was added. The mixture was filtered through celite and the resulting benzene solution was lyophilized to yield green 3.4 (0.14 mg, 70%). Crystals suitable for X-ray diffraction were obtained by slow evaporation of a concentrated pentane solution of 3.4 out into hexamethyldisiloxane at
−35 oC. 1H NMR (C6D6, δ): 9.6, 9.1, 8.5, 3.3, 2.4. IR (KBr, cm-1): 2052 (ν[N2]). eff
(Evans’ method, C6D6, 23 oC) = 1.6 μB
Synthesis of [SiPiPr3]Ru(Pme3) (3.5). [SiPiPr3]RuCl (0.20 g, 0.27 mmol) was dissolved in 10 mL of THF in a scintillation vial and Pme3 (84 μL, 0.81 mmol) was syringed in. The red/purple solution was placed inside a cold well cooled in a dry ice/acetone bath. KC8 (36 mg, 0.27 mmol) was added in one portion, and the resulting mixture was stirred inside the cold well for 10 min The mixture was stirred for an additional 15 min at room temperature. The volatiles were removed, and the product was extracted into benzene and filtered through Celite. The resulting benzene solution was lyophilized to yield 0.19 g (90%) of orange 3.5. Crystals suitable for X-ray diffraction were obtained by slow evaporation of a concentrated pentane solution. 1H NMR (C6D6, δ): 16.1, 9.0, 8.3, 8.2, 5.2,
−2.3. μeff (Evans’ method, C6D6, 23 oC) = 1.6 μB. Anal. Calcd for C39H63SiP4Ru: C, 59.67; H, 8.03; N, 0.00. Found: C, 59.67; H, 7.30; N, 0.24.
Alternative synthesis of 3.5. [SiPiPr3]RuN2 was dissolved in benzene and one equivalent of Pme3 was added via syringe. An immediate color change to yellow/orange with effervescence resulted, and the resulting solution was concentrated. Analysis by NMR showed only 3.5 with no 3.3 remaining.
Synthesis of [SiPiPr3]Os(Pme3) (3.6). [SiPiPr3]OsN2 (24 mg, 0.030 mmol) was dissolved in 5 mL Et2O in a scintillation vial and Pme3 (3.1 μL, 0.030 mmol) was syringed in, resulting in a lightening of color. After stirring for 2 min, volatiles were removed, and the resulting green film was triturated with hexamethyldisiloxane, resulting in a light green powder. The green solid was washed with a minimum amount of cold pentane and dried to yield green 3.6 (20. Mg, 78%). 1H NMR (C6D6, δ): 22.8, 9.4, 7.8, 5.8, 1.1, −1.9. μeff
(Evans’ method, C6D6, 23 oC) = 1.8 μB. Anal. Calcd for C39H63SiP4Os: C, 53.59; H, 7.26;
N, 0.00. Found: C, 53.73; H, 6.57; N, < 0.05.
Synthesis of {[SiPiPr3]Ru(N2)}+BArF4-
(3.7). [SiPiPr3]RuCl (0.10 g, 0.13 mmol) was dissolved in 16 mL of C6H6 and NaBArF4 (0.12 g, 0.13 mmol) was added in one portion.
A gradual color change from dark red/purple to orange took place over 1 hr. The mixture was stirred for an additional 3 hr and the reaction mixture was filtered through celite and lyophilized to yield orange 3.7 (0.18 g, 84%). Crystals suitable for X-ray diffraction were obtained from layering pentane over a concentrated CH2Cl2 solution of 3.7 at −35oC.
Layering pentane over a concentrated THF solution at RT alternatively resulted in crystals that yielded a solid-state structure with no N2 nor THF bound. Complex 3.7 could also be prepared by addition of AgOTf to an Et2O solution of 3.3. 1H NMR (d8-THF, δ):
8.21 (d, J = 7.6 Hz, 3H), 7.82 (s, 8H), 7.77 (d, J = 7.6 Hz, 3H), 7.59 (s, 4H), 7.46 (t, J = 7.6 Hz, 3H), 7.37 (t, J = 7.6 Hz, 3), 2.32 (m, 6H), 1.15 (s, 18H), 0.95 (s, 18H). 15N{1H,
−90 oC} NMR (d8-THF, δ): 337.5, 300.0. 31P{1H} NMR (CD2Cl2, δ): 69.1 (s).
Synthesis of {[SiPiPr3]Ru(N2)}−K+(THF)2 (3.8). [SiPiPr3]RuCl (0.10 g, 0.13 mmol) was dissolved in 8 mL of THF and placed inside a cold well cooled in a dry ice/acetone bath.
KC8 (21 mg, 0.15 mmol) was added in one portion, and the mixture was stirred inside the well for 10 min The reaction mixture was stirred for an additional 10 min at room temperature and the volatiles were removed. Benzene was added to the mixture and the mixture was filtered through celite. Volatiles were removed and the resulting [SiPiPr3]RuN2 was redissolved in THF and placed inside the cold well. A second batch of KC8 (36 mg, 0.27 mmol) was added in one portion, resulting in a color change to dark red.
The reaction mixture was stirred for 10 min inside the cold well and stirred for an
additional 10 min at room temperature. The dark red mixture was filtered through celite, and concentrated. Layering pentane over a concentrated THF solution resulted in dark crystals of 3.8 (85 mg, 73%) suitable for X-ray diffraction. 1H NMR (d8-THF, δ): 7.96 (d, J = 7.6 Hz, 3H), 6.88 (d, J = 8.0 Hz, 3H), 6.80 (t, J = 8.0 Hz, 3H), 2.41 (m, 6H), 0.97 (s, 18H), 0.71 (s, 18H). 13C{1H} NMR (d8-THF, δ): 151.9, 130.0, 124.8, 123.6, 121.9, 31.7, 18.4. 29Si{1H} NMR (d8-THF, δ): 90.7 (q, J = 20 Hz). 31P{1H} NMR (d8-THF, δ): 82.8 (s). IR (KBr, cm-1): 1960 (ν[N2]). Despite repeated attempts, satisfactory combustion analysis could not be obtained for this complex. However, combustion analysis was obtained for the 18-crown-6 complex, {[SiPiPr3]Ru(N2)}-K+(18-c-6)(3.8’).
Synthesis of {[SiPiPr3]Ru(N2)}-K+(18-c-6)(3.8’). {[SiPiPr3]Ru(N2)}-K+(THF)2 (50. Mg, 0.054 mmol) was dissolved in 5 mL of THF and a THF solution of 18-crown-6 (22 mg, 0.082 mmol) was added dropwise. The resulting solution was stirred for 30 min, and volatiles were removed. The residue was washed with Et2O (2 x 1 mL) and C6H6 (2 x 1 mL). Recrystallization from layering pentane over a concentrated THS solution resulted in dark crystals of {[SiPiPr3]Ru(N2)}-K+(18-c-6) (45 mg, 80%) that analyzed with one molecule of THF. 1H NMR (d8-THF, δ): 7.88 (d, J = 8.1 Hz, 3H), 7.18 (d, J = 7.8 Hz, 3H), 6.79 (m, 6H), 3.58 (s, 24H), 2.49 (br, 6H), 0.90 (s, 18H), 0.64 (s, 18H). 31P{1H}
NMR (d8-THF, δ): 79.7 (br) (s). IR (KBr, cm-1): 1992 (ν[N2]). Anal. Calcd. for C52H86N2O7KsiP3Ru: C, 56.14; H, 7.79; N, 2.52. Found: C, 56.21; H, 7.84; N, 2.78.
Synthesis of {[SiPiPr3]Os(N2)}-K+(THF)2 (3.9). [SiPiPr3]OsN2 (57 mg, 0.069 mmol) was dissolved in 4 mL of THF in a scintillation vial. The vial was placed inside a cold well cooled in a dry ice/acetone bath and KC8 (14 mg, 0.10 mmol) was added in one portion.
The resulting mixture was stirred for 15 min, and stirred for an additional 15 min at room
temperature. The dark red mixture was filtered through celite and volatiles were removed.
Pentane was layered over a concentrated THF solution of 3.9 to yield dark crystals (40 mg, 57%). 1H NMR (d8-THF, δ): 7.97 (d, J = 6.6 Hz, 3H), 7.20 (d, J = 6.9 Hz, 3H), 6.78 (m, 6H), 2.8 (br, 6H), 0.87 (s, 18H), 0.67 (s, 18H). 31P NMR (d8-THF, δ): 49.9 (br).
Crystals suitable for X-ray diffraction were obtained by layering pentane over a concentrated THF solution of 3.9. In light of the difficulties encountered in obtaining satisfactory combustion analysis for 3.9, the 18-crown-6 complex for 3.9, {[SiPiPr3]Os(N2)}-K+(18-c-6) (3.9’), was synthesized.
Synthesis of {[SiPiPr3]Os(N2)}-K+(18-c-6) (3.9’). {[SiPiPr3]Os(N2)}-K+(THF)2 (20. mg, 0.020 mmol) was dissolved in 4 mL of THF in a scintillation vial. 18-crown-6 (6.1 mg, 0.023 mmol) was dissolved in 1 mL of THF and added dropwise to the dark red solution, resulting in no change in color. The resulting solution was stirred for 15 min, and the volatiles were removed, resulting in a dark red film. Triturating with Et2O resulted in the precipitation of red microcrystals, and the crystalline material was washed with Et2O, pentane, and dried (19 mg, 90%) to yield 3.9’ that analyzed with one molecule of THF.
1H NMR (d8-THF, δ): 7.94 (d, J = 7.0 Hz, 3H), 7.17 (d, J = 7.0 Hz, 3H), 6.81 (m, 3H), 6.72 (m, 3H), 3.52 (s, 24H), 2.40 (br, 6H), 0.83 (s, 18H), 0.65 (s, 18H). 13C{1H} NMR (d8-THF, δ): 158.7 (m), 154.1 (m), 130.0 (m), 125.3, 123.8, 122.1, 69.3, 33.5 (br), 18.9, 18.7. 29Si{1H} NMR (d8-THF, δ): 85.2 (q, J = 16 Hz). 31P{1H} NMR (d8-THF, δ): 50.0.
Anal. Calcd. for C52H86N2O7KsiP3Os: C, 51.98; H, 7.21; N, 2.33. Found: C, 51.68; H, 6.97; N, 1.77.
Synthesis of [SiPiPr3]Ru(H)(N2) (3.10). [SiPiPr3]RuCl (51 mg, 0.068 mmol) was dissolved in 5 mL of THF and the reaction mixture was placed inside a cold well cooled
in a dry ice/acetone bath. LiEt3BH (68 μL, 0.068 mmol) was added dropwise. The resulting solution was stirred for 15 min inside the cold well. The reaction mixture was stirred for an additional 20 min at room temperature and volatiles were removed.
Benzene was added to the mixture and the mixture was filtered through Celite.
Lyophilization of the benzene solution resulted in pale red 3.10 (48 mg, 96%). Crystals suitable for X-ray diffraction were obtained by vapor diffusion of pentane into a concentrated benzene solution of 3.10. 1H NMR (C6D6, δ): 8.19 (d, J = 7.2 Hz, 2H), 8.00 (d, J = 7.2 Hz, 1H), 7.43 (m, 2H), 7.22-7.01 (m, 7H), 2.69 (br, 2H), 2.43 (sep, J = 6.3 Hz, 2H), 2.26 (sep, J = 6.6 Hz, 2H), 1.43-1.11 (m, 18H), 0.90-0.62 (m, 18H), -10.3 (dt, J = 62 Hz, 35 Hz). 13C{1H} NMR (C6D6, δ): 158.6 (d, J = 48 Hz), 155.9 (m), 150.0 (m), 147.1 (d, J = 35 Hz), 133.6 (d, J = 20 Hz), 132.9 (t, J = 10 Hz), 130.0-129.0 (m), 127.7, 127.1, 126.2, 32.2, 29.8 (m), 28.5 (d, J = 12 Hz), 22.6, 20.5, 20.4, 20.0, 19.9, 19.7, 19.6, 19.2.
29Si{1H} NMR (C6D6, δ): 80.0 (q, J = 13 Hz). 31P{1H} NMR (C6D6, δ): 73.0 (br, 2P), 65.8 (s, 1P). IR (KBr, cm-1): 2140 (ν[N2]).
Synthesis of [SiPiPr3]Ru(Nar) Ar = C6H4CF3 (3.11). [SiPiPr3]RuN2 (43 mg, 0.058 mmol) was dissolved in 6 mL Et2O in a scintillation vial and the vial was placed inside a cold well cooled in a dry ice/acetone bath. ArN3 (11 mg, 0.058 mmol) was dissolved in 1 mL Et2O in a 4 mL vial and also cooled inside the cold well. The azide solution was added dropwise to the solution of [SiPiPr3]RuN2, resulting in a rapid color changed to dark red/purple. The solution was stirred for 10 min inside the cold well, and stirred for an additional 10 min at room temperature. Volatiles were removed, and the residue was washed with a small portion of cold pentane. Crystals suitable for X-ray diffraction were obtained by slow evaporation of a 1:1 = Et2O:pentane solution out into
hexamethyldisiloxane (23 mg, 46%). 1H NMR (C6D6, δ): 9.1, 7.3, 7.0, 5.8. μeff (Evans’
method, C6D6, 23 oC) = 1.5 μB
Synthesis of [SiPiPr3]Os(Nar) Ar = C6H4CF3 (3.12). [SiPiPr3]OsN2 (47 mg, 0.057 mmol) was dissolved in 10 mL Et2O in a scintillation vial, and the vial was placed inside a cold well cooled in a dry ice/acetone bath. ArN3 (11 mg, 0.057 mmol) was dissolved in 1 mL Et2O in a 4 mL vial and also cooled inside the cold well. The azide solution was added dropwise to the solution of [SiPiPr3]RuN2, resulting in a gradual color chang from dark green dark red/orange. The solution was stirred for 10 min inside the cold well, and stirred for an additional 5 min at room temperature. Volatiles were removed, and crystals suitable for X-ray diffraction were obtained by slow evaporation of a 1:1 = Et2O: pentane solution out into hexamethyldisiloxane (22 mg, 41%). 1H NMR (C6D6, δ): 9.9, 6.1, 5.8 (very broad). eff (Evans’ method, C6D6, 23 oC) = 1.5 μB
Reaction of 3 with I2. [SiPiPr3]RuN2 (22 mg, 0.030 mmol) was dissolved in 4 mL of Et2O in a scintillation vial and placed inside a cold well cooled in a dry ice/acetone bath.
Iodine (3.8 mg, 0.015 mmol) was added to the solution in one portion, and the resulting mixture was allowed to stir for 10 min inside the well. A gradual color change to a red/purple solution resulted, and the solution was allowed to stir for ten additional minutes. Volatiles were removed to yield a red solid (21 mg, 85%). The identity of the product, [SiPiPr3]RuI, was confirmed through 1H, 31P{1H}, and by x-ray crystallography.
1H NMR (C6D6, δ): 8.26 (d, J = 7.0 Hz, 3H), 7.24-7.18 (m, 6H), 7.01(t, 3H), 2.50 (m, 6H), 1.17 (m, 18H), 0.88 (s, 18H). 31P NMR (C6D6, δ): 70.1 (s).
Reaction of 3 with PhS-SPh. [SiPiPr3]RuN2 (22 mg, 0.029 mmol) was dissolved in 4 mL Et2O in a scintillation vial, and the vial was placed inside a cold well cooled in a dry
ice/acetone bath. Diphenyldisulfide (3.2 mg, 0.015 mmol) was added in one portion. The color of the reaction mixture turned to a bright purple color after several minutes. The reaction vial was stirred for 15 min inside the cold well and 15 min at room temperature, resulting in precipitation of a purple solid. Volatiles were removed, which resulted in a purple solid. The solid was washed with cold Et2O and dried (19 mg, 80%). The identity of the product, [SiPiPr3]Ru(SPh), was confirmed through 1H, 31P{1H}, and by x-ray crystallography. 1H NMR (C6D6, δ): 8.11 (d, J = 6.5 Hz, 3H), 7.98(d, J = 7.5 Hz, 2H), 7.35-7.01(m, 12H), 2.68 (m, 6H), 1.13 (m, 18H), 0.93 (s, 18H). 31P{1H} NMR (C6D6, δ):
70 (br).
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