Hydrocondensation of Carbon Dioxide
Organometallics, Vol. 15, No. 15, 1996 3421
Ta ble 5. Ca ta lytic Activity of th e An ion s 1 a n d 2 w ith P r om oter a n d Ad d itive
catalysta
promoter
additive
none
none
HC(OCH3)3
none
none
H2O
HC(OCH3)3
ratio
TON
[Ru(CO)3Cl3]-
none
1
32
170
246
71
459
80
[Ru(CO)3Cl3]-
K[OCH3]
K[OCH3]
none
K[OCH3]
K[OCH3]
K[OCH3]
1:10
1:10:100
1
1:10
1:10:100
1:10:100
[Ru(CO)3Cl3]-
[Ru2(CO)4(CO2CH3)2(OCH3)Cl2]-
[Ru2(CO)4(CO2CH3)2(OCH3)Cl2]-
[Ru2(CO)4(CO2CH3)2(OCH3)Cl2]-
[Ru2(CO)4(CO2CH3)2(OCH3)Cl2]-
746
a
Cation [N(PPh3)2]+. Experimental conditions: 0.01 mmol of Ru, 10 mL of CH3OH, 60 bar (CO2/H2 ) 20/40), 160 °C, 14 h.
Elmer FT-IR 1720X spectrophotometer with 0.1 mm cells
equipped with CaF2 windows and are reported in cm-1
Mass spectra were obtained on Ribermag 10-10 mass
3.85, 3.92, 3.95, 4.08, 4.10 ppm (6 s, 3 OCH3). 13C NMR
(acetone-d6): δ 48.9, 51.2, 53.5, 66.0, 69.6, 70.6 ppm (6 s, 3
OCH3).
.
a
spectrometer. Elemental analyses were performed by the
Mikroelementaranalytische Laboratorien at Zurich. The fol-
lowing starting materials were prepared according to pub-
lished procedures: Ru3(CO)12,15 [N(PPh3)2]I,16 and [N(PPh3)2]-
[Ru(CO)3I3].17
Rea ction of Com p lexes 2 a n d 2a w ith K[OCH3]. To a
solution of the [N(PPh3)2] salt of 2 (100 mg, 0.093 mmol) in 10
mL of methanol was added 1 equiv of K[OCH3] (25% metha-
nolic solution, 28 µL, 0.093) drop by drop. Infrared monitoring
in the ν(CO) region indicated the formation of a new compound
3 [2043 (s) and 1979 (s) cm-1]. This complex reacted with a
second 1 equiv of K[OCH3] to form a complex 4 [2032 (s) and
1965 (vs) cm-1] characteristic of an Ru(CO)3 unit. Complexes
3 and 4 decomposed to give a black oil on evaporation of the
methanol. By reaction of the iodo analogue 2a with methoxide
(2 equiv), the solution showed the same infrared spectrum
[2032 (s) and 1965 (vs) cm-1] of 4, being indicative of the
absence of halide ligands in 4.
Syn th esis of [N(P P h 3)2][Ru 2(CO)4(µ2-η2-CO2CH3)2(µ2-
OCH3)(O-p-C6H4NO2)Cl] ([N(P P h 3)2]3a ). The [N(PPh3)2]
salt of 2 (100 mg, 0.093 mmol) was dissolved in 10 mL of
methanol. Addition at 25 °C of 1 equiv of phenolate K[O-p-
C6H4NO2] (16.5 mg, 0.093 mmol), prepared from the corre-
sponding phenol and KH in the THF, resulted in the forma-
tion of complex 3a . The solution was filtered through filter
pulp. After evaporation of the solvent, we obtained 100
mg of the [N(PPh3)2] salt of 3a (61% yield). Anal. Calcd for
Syn th esis of [N(P P h 3)2][Ru (CO)3Cl3] ([N(P P h 3)2]1). The
complex [N(PPh3)2][Ru(CO)3Cl3] was prepared by a "one-pot”
synthesis from RuCl3‚3H2O and [N(PPh3)2]Cl. In a 100 mL
stainless steel autoclave, RuCl3‚3H2O (500 mg, 1.91 mmol) and
[N(PPh3)2]Cl (1096 mg, 1.91 mmol) were dissolved in 30 mL
of distilled methanol. The autoclave was pressurized with CO
(10 bar) and heated at 90 °C for 3 h. After cooling and venting,
the pale yellow solution was filtered under a nitrogen atmo-
sphere through a 2 cm layer of filter pulp and concentrated to
about 10 mL. The product was crystallized at -35 °C. After
14 h, the crystalline precipitate was filtered out and dried
under vacuum (990 mg, 62%). The filtrate was concentrated
and cooled to -35 °C to give a second crop of 290 mg of product
(total yield 81%). Anal. Calcd for C39H30NO3P2Cl3Ru: C,
56.43; H, 3.64; N, 1.69. Found: C, 56.04; H, 3.85; N, 1.55. IR
(ν(CO), CH3OH): 2129 (s) and 2055 (vs) cm-1
.
Syn th esis of [N(P P h 3)2][Ru 2(CO)4(µ2-η2-CO2CH3)2(µ2-
OCH3)Cl2] ([N(P P h 3)2]2). The complex [N(PPh3)2][Ru2(CO)4(µ2-
η2-CO2CH3)2(µ2-OCH3)Cl2] was prepared by dropwise addition
of 1.5 equiv of K[OCH3] (25% methanolic solution, 266 µL,
0.903 mmol) to a methanol solution (40 mL) of [N(PPh3)2]-
[Ru(CO)3Cl3] (500 mg, 0.602 mmol) at 25 °C. The solution
remained colorless. The solution was filtered under the same
conditions as in the synthesis of 1 and concentrated to about
10 mL. The complex was crystallized at -35 °C and gave
(after two crystallizations) colorless crystals of 2 (245 mg,
76% yield). Anal. Calcd for C45H39NO9P2Cl2Ru2: C, 50.38; H,
3.66; N, 1.31. Found: C, 50.06; H, 3.92; N, 1.43. IR (CH3-
C
51H43N2O12P2ClRu2: C, 52.11; H, 3.69; N, 2.38; Cl, 3.01.
Found: C, 51.67; H, 3.59; N, 2.54; Cl, 2.96. IR (CH3OH):
ν(CO), 2043 (s), 1980 (s) cm-1; ν(OCO), 1530 (m) cm-1
.
1H
NMR (acetone-d6): δ 7.53-7.78 ppm (m, phenyls, PPN+); δ
6.81, 8.04 ppm (2d, C6H4); δ 3.56-3.96 ppm (m, 3 OCH3).
Syn th esis of [N(P P h 3)2][Ru 2(CO)6(OCH3)3(OR)2] (a n -
ion s: R ) p-C6H4CH3, 4a ; R ) p-C6H4C(CH3)3, 4b). The
[N(PPh3)2] salt of 2 (100 mg, 0.093 mmol) was dissolved in 10
mL of methanol, and 2 equiv of phenolate K[OR] (R ) p-C6H4-
CH3, 27 mg, 0.186 mmol; R ) p-C6H4C(CH3)3, 35 mg, 0.186
mmol) prepared from to the corresponding phenol and KH in
THF was added at 25 °C. The solution was filtered, and after
evaporation of the solvent, we obtained the [N(PPh3)2] salts
of 4a (100 mg, 88% yield) and 4b (100 mg, 83% yield). Anal.
Calcd for C59H53NO11P2Ru2 (4a ): C, 58.27; H, 4.39; N, 1.15.
Found: C, 57.57; H, 4.46; N, 1.15. IR (CH3OH, 4a , ν(CO)):
2039 (s), 1973 (vs). 1H NMR (4a , acetone-d6): δ 7.53-7.79
ppm (m, phenyls, PPN+); δ 6.73-6.94 ppm (m, 2 C6H4); δ 3.52-
4.01 ppm (m, 3 OCH3); δ 2.20 ppm (s, 2 CH3). Anal. Calcd
for C65H65NO11P2Ru2 (4b): C, 60.04, H, 5.04. Found: C, 60.03;
H, 5.18. IR (CH3OH, 4b, ν(CO)): 2038 (s), 1973 (vs). 1H NMR
(4b, acetone-d6): δ 7.53-7.71 ppm (m, phenyls, PPN+); δ 6.79-
7.22 ppm (m, 2 C6H4); δ 3.47-4.01 ppm (m, 3 OCH3); δ 1.26
ppm (s, 6 CH3). MS: m/z (4b) ) 763.
Rea ction of [Ru 2(CO)6(OCH3)5]- (4) w ith CO2. The
[N(PPh3)2] salt of 2 (100 mg, 0.093 mmol) was dissolved in 10
mL of methanol, and 2 equiv of K[OCH3] (25% methanolic
solution, 56 µL, 0.186 mmol) was added at 25 °C. After the
infrared spectrum indicated the complete conversion into 4 (20
min), the solution was transferred into an autoclave, pressur-
ized with CO2 (20 bar), and stirred 14 h at 160 °C. After
cooling and venting, the solution showed no change in the
infrared spectrum and contained 4.
OH): ν(CO), 2057 (s), 1993 (s), cm-1; ν(OCO), 1528 (m) cm-1
.
1H NMR (acetone-d6): δ 7.53-7.80 ppm (m, phenyls, [N-
(PPh3)2]+); δ 3.57, 3.73, 3.77, 3.81, 3.86, 3.91 ppm (6 s, 3 OCH3).
13C NMR (acetone-d6): δ 49.0, 49.1, 51.0, 53.2, 63.2, 63.9 ppm
(6 s, 3 OCH3). MS: m/z (2) ) 534.
Syn th esis of [N(P P h 3)2][Ru 2(CO)4(µ2-η2-CO2CH3)2(µ2-
OCH3)I2] ([N(P P h 3)2]2a). The complex [N(PPh3)2][Ru(CO)3I3]17
(200 mg, 0.181 mmol) was dissolved in 20 mL of metha-
nol. Then 1.5 equiv of K[OCH3] (25% methanolic solution,
80 µL, 0.272 mmol) was added drop by drop at 25 °C. The
orange solution was filtered and concentrated to about 5
mL. The complex of 2a was crystallized at -35 °C giving
orange crystals (75 mg, 0.060 mmol, 66% yield). Anal. Calcd
for C45H39NO9P2I2Ru2: C, 43.09; H, 3.13; N, 1.12; I, 20.21.
Found: C, 43.24; H, 3.20; N, 1.08; I, 20.09. IR (CH3OH): ν(CO),
2042 (s), 1977 (s) cm-1; ν(OCO), 1530 (m) cm-1
.
1H NMR
(acetone-d6): δ 7.53-7.80 ppm (m, phenyls, PPN+); δ 3.78,
(15) Bruce, M. I.; J ensen, C. M.; J ones, N. L. Inorg. Synth. 1989,
25, 259.
(16) Kirtley, S. W.; Andrews, M. A.; Bau, R.; Grynkewich, G. W.;
Marks, T. J .; Tipton, D. L.; Whittlesey, B. R. J . Am. Chem. Soc. 1977,
99, 7154.
(17) Lugan, N.; Lavigne, G.; Soulie, J .-M.; Fabre, S.; Kalck, Ph.;
Saillard, J .-Y.; Halet, J .-F. Organometallics 1995, 14, 1712.
Rea ction of [Ru 2(CO)6(OCH3)5]- (4) w ith H2. The [N-
(PPh3)2] salt of 2 (100 mg, 0.093 mmol) was dissolved in 10