M. Aydemir et al.
delay of 1.4 s, 75k data points, a pulse width of 30ꢀ and CDCl3
(77.23 ppm) as the internal reference. 31P NMR spectra were
collected at 162 MHz using a 65 000 Hz spectra width, a relaxation
delay of 0.5 s, 150k data points, a pulse width of 30ꢀ and CDCl3 as
the external reference.
(m, o-protons of phenyls, 4H), 7.36–7.41 (m, m- and p-protons of
3
3
phenyls, 6H), 7.35 (d, H-5, 1H, J 2.0Hz), 6.30 (dd, H-4, 1H, J 2.0
and 3.2), 6.11 (d, H-3, 1H, 3J 3.2 Hz), 4.01 (dd, -CH2-, 2H, 3J 6.8 and
8.8 Hz), 2.38 (dt, -NH-, 1H, J 6.8 and 13.2 Hz); 13C NMR (100.6MHz,
CDCl3): d = 43.09 (-CH2-), 106.27 (C-3), 110.26 (C-4), 141.71 (d, C-5),
128.30 (d, m-carbons of phenyls, 3J(31P-13C) 6.3 Hz), 128.58
(s, p-carbons of phenyls), 131.44 (d, o-carbons of phenyls, 2J(31P-13C)
Melting points
1
19.0 Hz), 140.95 ppm (d, i-carbons of phenyls, J(31P-13C) 12.1 Hz),
Melting point determinations were performed on samples using
a Gallenkamp model (Sanyo Biomedical Equipment) apparatus
3
154.95 (d, C-2, J(31P-13C) 6.0Hz), assignment was based on the
1H-13C heteronuclear correlation (HETCOR), distortionless enhance-
with a ramp rate of 5ꢀC minÀ1
.
1
ment by polarization transfer (DEPT) and H-1H correlation spec-
FT-IR
troscopy (COSY) spectra; 31P NMR (d in ppm rel. to H3PO4, in CDCl3):
42.71 (s); IR, (KBr): υ = 804 (P-N), 1434 (P-Ph), 3383 (N-H) cmÀ1
;
FT-IR spectra were recorded on a Mattson 1000 ATI Unicam FT-IR
spectrometer (ATI-UNICAM Inc.). Optical-grade, random cuttings
of KBr (International Crystal Laboratories, Garfield, NJ, USA) were
ground with 1.0 wt% of the sample for FT-IR analysis.
C17H16ONP (281.3 g molÀ1): calc. C 72.59, H 5.73, N 4.98; found C
72.49, H 5.64, N 4.95.
[Ru(Ph2PNHCH2-C4H3O)(ꢀ6-p-cymene)Cl2] 2
To a solution of [Ru(Z6-p-cymene)(m-Cl)Cl]2 (0.312 g, 0.51 mmol)
in tetrahydrofuran, a solution (THF, 30 ml) of [Ph2PNHCH2-
C4H3O] 1 (0.287 g, 1.02 mmol) was added. The resulting reaction
mixture was allowed to proceed with stirring at room tempera-
ture for 1 h. After this time, the solution was filtered and the sol-
vent evaporated under vacuum. the solid residue thus obtained
was washed with diethyl ether (3 Â 10 ml) and then dried under
vacuum. Following recrystallization from diethylether/CH2Cl2, a
red crystalline powder was obtained. Yield 0.560 g, 93.5%, m.p.
= 192–193ꢀC. 1H NMR (d in ppm rel. to TMS, J Hz, in CDCl3):
7.93–7.97 (m, 4H, o-protons of phenyls), 7.42–7.59 (m, 6H,
m- and p-protons of phenyls), 7.20 (br, 1H, H-5), 6.16 (br, 1H, H-4), ),
6.01 (br, 1H, H-3), 5.27 (d, 2H, 3J = 5.3Hz, aromatic protons of
p-cymene), 5.10 (d, 2H, 3J = 5.7Hz, aromatic protons of p-cymene),
Materials
Unless otherwise stated, all reactions were carried out under argon
using Schlenk glassware. Solvents were dried using established pro-
cedures and distilled under argon immediately prior to use. The
starting materials [Ru(Z6-p-cymene)(m-Cl)Cl]2,[19] [Ru(Z6-benzene)
(m-Cl)Cl]2,[20] Rh(m-Cl)(cod)]2
and [Ir(Z5-C5Me5)(m-Cl)Cl]2
were
[21]
[22]
prepared according to literature procedures. Analytical-grade and
deuterated solvents were purchased from Merck. PPh2Cl and furfur-
ylamine are purchased from Fluka and used as received.
GC Analyses and General Procedure for the Transfer Hydro-
genation of Ketones
3
3
GC analyses were performed on an HP 6890N gas chromatograph
equipped with capillary column (5% biphenyl, 95% dimethylsilox-
ane) (30 m  0.32 mm  0.25 mm). The GC parameters for transfer
hydrogenation of ketones were as follows; initial temperature
110ꢀC; initial tiÀm1e 1 min; solvent delay 4.48 min; temperature
ramp 80ꢀC min ; final temperature 200ꢀC; final time 21.13 min;
injector port temperature 200ꢀC; detector temperature 200ꢀC,
injection volume 2.0ml. Typical procedure for the catalytic hydro-
gen transfer reaction: a solution of complexes [Ru(Ph2PNHCH2-
C4H3O)(Z6-p-cymene)Cl2] 2, [Ru(Ph2PNHCH2-C4H3O)(Z6-benzene)
Cl2] 3, [Rh(Ph2PNHCH2-C4H3O)(cod)Cl] 4 or [Ir(Ph2PNHCH2-C4H3O)
(Z5-C5Me5)Cl2] 5 (0.005 mmol), KOH (0.025 mmol) and the cor-
responding ketone (0.5 mmol) in degassed iso-PrOH (5 ml) were
refluxed for 45 min for 2, 20 min for 3, 2h for 4 and 4 h for 5. After
this period a sample of the reaction mixture was taken off, diluted
with acetone and analysed immediately by GC. Conversions
obtained are related to the residual unreacted ketone.
3.61 (dt, 1H, J = 6.4 and 13.0 Hz, NH), 3.51 (dd, 2H, J = 6.6 and
7.3 Hz, -CH2-), 2.64 (m, 1H, -CH- of p-cymene), 1.97 (s, 3H, CH3-Ph
of p-cymene), 0.86 (d, 6H, 3J = 6.8Hz, (CH3)2CHPh of p-cymene);
13C NMR (d in ppm rel. to TMS, J Hz, in CDCl3): 17.44 (CH3Ph of
p-cymene), 21.32 ((CH3)2CHPh of p-cymene), 30.06 (-CH- of
2
p-cymene), 40.08 (d, J = 10.1 Hz, -CH2-), 86.19, 91.08 (aromatic
carbons of p-cymene), 94.08, 108.21 (quaternary carbons of
p-cymene), 106.71 (C-3), 110.14 (C-4), 141.43 (C-5), 128.14
(d, 3J = 10.1 Hz, m-carbons of phenyls), 130.77 (d, 4J = 2.0 Hz,
p-carbons of phenyls), 132.86 (d, 2J = 11.1 Hz, o-carbons of
phenyls), 133.95 (d, 1J = 51.3 Hz, i-carbons of phenyls), 152.96
1
(d, 3J = 6.0 Hz, C-2); assignment was based on the H-13C HETCOR,
DEPT and 1H-1H COSY spectra; 31P NMR (d in ppm rel. to H3PO4, in
CDCl3): 60.98 (s); IR, (KBr): υ= 845 (P-N), 1433 (P-Ph), 3375 (N-H)
cmÀ1; C27H30NPORuCl2 (587.5 g molÀ1): calc. C 55.20, H 5.15, N
2.38; found C 55.01, H 5.11, N 2.35.
Synthesis of [Ru(Ph2PNHCH2-C4H3O)(ꢀ6-benzene)Cl2] 3
Synthesis of the Ligand and its Transition Metal Complexes
A mixture of [Ru(Z6-benzene)(m-Cl)Cl]2 (0.255 g, 0.51 mmol) and
[Ph2PNHCH2-C4H3O] (0.287 g, 1.02 mmol) in 15 ml THF was stirred
at room temperature for 2 h. The volume of the solvent was then
reduced to 0.5 ml before addition of diethyl ether (10 ml). The
precipitated product was filtered and dried in vacuo, yielding 3
as a red microcrystalline powder. Yield 0.510 g, 94.1%, m.p. =
180ꢀC (dec.). 1H NMR (400.1 MHz, CDCl3) d = 7.91–7.97 (m, 4H,
o-protons of phenyls), 7.51–7.52 (m, 6H, m- and p-protons of phe-
nyls), 7.22 (d, 1H, 3J = 1.8 Hz, H-5), 6.17 (dd, 1H, 3J = 1.8 and
3.2 Hz, H-4), 6.02 (d, 1H, 3J = 3.1 Hz, H-3), 5.41 (s, 6H, aromatic pro-
tons of benzene), 3.68 (dd, 2H, 3J = 7.6 and 7.8 Hz, -CH2-), 3.55
(m, 1H, NH); 13C NMR (100.6MHz, CDCl3): d = 40.20 (d, 2J = 9.1Hz, -
CH2-), 88.78 (d, 2J = 4.0 Hz, aromatic carbon of benzene), 106.92
Furfuryl-(N-diphenylphosphino)amine, [Ph2PNHCH2-C4H3O] 1
Chlorodiphenylphosphine (0.237 g, 1.02 mmol) was added drop-
wise over a period of 15 min to a stirred solution of furfurylamine
(0.099 g, 1.02 mmol) and triethylamine (0.104 g, 1.02 mmol) in
THF (40 ml) at 0ꢀC. The mixture was then stirred at room temper-
ature for 1 h and the white precipitate (triethylammonium chlo-
ride) was filtered under argon and the solvent was removed
under reduced pressure. The residue was then washed with
dried cold diethyl ether (2 Â 10 ml) and dried in vacuo to pro-
duce a clear, white viscous oily compound 1. Yield 0.261 g,
91.1%. 1H NMR (d in ppm rel. to TMS, J Hz, in CDCl3): d = 7.45–7.48
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Appl. Organometal. Chem. 2012, 26, 1–8