10.1002/ejic.201900307
European Journal of Inorganic Chemistry
FULL PAPER
analyses were performed by Medac Ltd., Surrey, UK. The compounds
[Ru(LOEt)Cl2(MeCN)] and [Ru(LOEt)Cl2(tBuNH2)] (1)[15] were prepared as
described elsewhere. All other reagents were purchased from standard
commercial sources and used without further purification.
been able to obtain satisfactory elemental analysis for this purple
complex owing to its air-sensitivity and hydroscopic nature.1H NMR (400
MHz, CDCl3, 25 oC, D2O): 1.22 (overlapping t, 12H, CH3), 1.27 (s, 9H,
tBu), 1.31 (t, 6H, CH3), 4.01 (m, 8H, CH2), 4.19 (m, 4H, CH2), 5.22 (s, 5H,
Cp), 7.34 (d, 2H, OTs), 7.66 (d, 2H, OTs). 31P{1H} NMR (162 MHz, CDCl3,
D2O): 120.54 (m), 122.95 (m).
Preparations of [Ru(LOEt)Cl2(L)] (L = pyridine (2), imidazole (3)):
These complexes were prepared according to a previously published
method.[15] A solution of [Ru(LOEt)Cl2(MeCN)] (100 mg, 0.134 mmol) and
1 equivalent of L (0.134 mmol) in tetrahydrofuran (8 mL) was refluxed
overnight. The solvent was removed in vacuo. Column chromatography
on silica using ethyl acetate/hexane as eluent afforded orange crystals.
For 2: Yield: 85 mg (81 %). IR (KBr, cm-1): 1380-1480 [(C-N)].
C22H40Cl2CoNO9P3Ru (785.97) calcd. C 33.60, H 5.13, N 1.78; found C
33.60, H 5.08, N 1.76. For 3: Yield: 75 mg (72 %). IR (KBr, cm-1): 3144
[(N-H)], 1388-1484 [(C-N)]. C20H39Cl2CoN2O9P3Ru (774.96) calcd. C
30.98, H 5.07, N 3.61; found C 31.07, H 5.05, N 3.55.
Preparation of [RuII(LOEt)(MeCN)2(tBuNH2)](PF6) (9): A mixture of 5
(100 mg, 0.092 mmol) and Zn dust (500 mg) in acetonitrile (10 mL) was
stirred overnight at room temperature. NH4PF6 (15 mg, 0.092 mmol) was
added and the mixture was stirred for 2 h. The solvent was removed in
vacuo, and the residue was washed with hexane. Recrystallization from
CH2Cl2/hexane afforded red crystals that were suitable for X-ray
diffraction study. Yield: 75 mg (86 %). 1H NMR [400 MHz, CDCl3, 25 oC,
(CD3)2CO]: = 1.21 (s, 9H, tBu), 1.26-1.32 (overlapping t, 18H, CH3),
2.80 (s, 9H, MeCN), 2.86 (br, 2H, NH2), 4.05-4.18 (m, 12H, CH2), 5.08 (s,
5H, Cp) ppm. 31P{1H} NMR [162 MHz, CDCl3, (CD3)2CO]: = 120.1 (s,
-
LOEt-), -144.41, (quintet, PF6 ) ppm. C25H52CoF6N3O9P4Ru (937.09) calcd.
Preparation of [Ru(LOEt)Cl2{NHC(CH3)NHtBu}] (4): A solution of 1 (100
mg, 0.134 mmol) in neat tert-butylamine (10 mL) was refluxed overnight.
The solvent was removed in vacuo. Column chromatography on silica
using ethyl acetate/hexane as eluent afforded red crystals. Yield: 85 mg
(77 %). IR (KBr, cm-1): 3312, 3379 [(N-H)]. C23H49Cl2CoN2O9P3Ru
(821.04) calcd. C 33.63, H 6.01, N 3.41; found C 33.71, H 5.99, N, 3.43.
C 32.06, H 5.60, N 4.49; found C 31.85, H 5.45, N 4.58.
General procedure of the Ru-catalyzed C-H oxidation : A mixture of
Ru aqua complex (0.16 mol), hydrocarbon substrate (0.16 mmol) and
TBHP (5.5 M in decane, 58 L, 0.32 mmol) in water (3 mL) was stirred in
air for 16-48 h in a 10 mL screw capped vial equipped with a magnetic
stirring bar. The reaction mixture was then extracted with CH2Cl2 (3 x 10
mL) and dried over anhydrous Na2SO4. The yields of the oxidized
products were determined by GLC using bromobenzene as internal
standard.
Preparation of [Ru(LOEt)(H2O)2(L)][OTs]2 (L = ButNH2 (5), pyridine (6),
imidazole (7)): A solution of [Ru(LOEt)Cl2(L)] (0.102 mmol) and 2
equivalents of AgOTs (0.205mmol) in 1 M p-toluenesulfonic acid (20 mL)
was refluxed overnight. The AgCl formed was filtered off and extracted
with CH2Cl2 and then dried over anhydrous Na2SO4.The volatiles were
pumped off and washed with hexane. Recrystallization from
CH2Cl2/hexane afforded yellow crystals. For 5: Yield: 90 mg (81 %). IR
(KBr, cm-1): 3143, 3228 [(N-H)]. C35H64CoNO17P3RuS2 (1088.12) calcd.
C 38.64, H 5.93, N 1.29; found C 36.53, H 5.52, N, 1.11. For 6: Yield: 85
mg (76 %). IR (KBr, cm-1): 1390-1477 [(C-N)]. C36H58CoNO17P3RuS2
(1094.07) calcd. C 39.53, H 5.34, N 1.28; found C 38.67, H 5.62, N 1.22.
For 7: Yield: 85 mg (76 %). IR (KBr, cm-1): 3120 [(N-H)], 1389-1490
[ν(C-N)]. C34H57CoN2O17P3RuS2 (1083.07) calcd. C 37.71, H 5.31, N 2.59;
found C 36.97, H 5.41, N 2.51.
X-ray Crystallography: Crystallographic data and refinement details for
complexes 4, 5, 7, 8 and 9 are listed in Table 3. The diffraction intensity
data of complexes 4, 8 and 9 were collected with a Rigaku GeminiTM
Ultra X-ray Diffractometer with monochromatized Cu-K radiation (=
1.54178 Å) at 173 K. The diffraction intensity data of complexes 5 and 7
were collected with a Rigaku GeminiTM Ultra X-ray Diffractometer with
monochromated Mo-K radiation ( = 0.71073 Å) at 298 and 173 K,
respectively. Diffraction data of 4, 5, 7, 8 and 9 were collected and
processed using the CrysAlisPro software (Rigaku, 2012). Empirical
absorption corrections were performed using spherical harmonics,
implemented in SCALE3 ABSPACK scaling algorithm in the CrysAlisPro
software suite. Structure solution and refinement for all complexes were
performed using the Olex2 software package[26] (which embedded
SHELXTL[27]). All the structures were solved by direct methods,
expanded by difference Fourier syntheses and refined by full matrix
least-squares on F2. All non-hydrogen atoms were refined anisotropically
with a riding model for the hydrogen atoms expect noted separately. All
the pictures of molecules were made using XP implemented in
SHELXTL.[27] CCDC 1518063-1518067 contain the supplementary
crystallography data for complexes 4, 5, 7, 8 and 9, respectively. These
data can be obtained free of charge from the Cambridge Crystallographic
Preparation of [Ru(LOEt)(H2O)3](OTs)2 (8): A solution of 5 (80 mg, 0.097
mmol) and 2 equivalents of AgOTs (60 mg, 0.214 mmol) in 1 M p-
toluenesulfonic acid (20 mL) was refluxed overnight. The AgCl formed
was filtered off and extracted with CH2Cl2 and then dried over anhydrous
Na2SO4. The volatiles were pumped off and washed with hexane.
Recrystallization from CH2Cl2/hexane afforded yellow crystals. Yield: 85
mg (85 %). C31H55CoO18P3RuS2 (1033.04) calcd. C 36.05, H 5.37; found
C 35.57, H 4.35.
Reduction of 5 with Zn in water: A mixture of 5 (10 mg) and zinc dust
(100 mg) in D2O (2 mL) was stirred at room temperature under argon for
5 min. The solution changed from yellow to purple gradually. NMR
spectroscopy indicated that the purple species, which could be isolated
as a solid upon extraction with CH2Cl2 and precipitation with hexanes, is
a diamagnetic complex, presumably a RuII aqua complex. We have not
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