Pt(II) Complexes with a NoWel P-N-P Ligand
evaporated to dryness, and the resulting thick oil was extracted five
times with 25 mL of pentane. Evaporation of the pentane solutions
to dryness led to 1 as a colorless oil (1.52 g, 42% yield). It could
be further purified by distillation through a short path elbow (bp
150 °C/0.01 mmHg). Anal. Calcd for C31H27NO2P2: C, 73.37; H,
5.36; N, 2.76. Found: C, 73.25; H, 5.18; N, 2.57. MS (FAB+, NBA
matrix): m/z 508 ([M + 1]+, 10%), 306 ([M - OPPh2]+, 65%),
230 ([M + 1 - OPPh2 - Ph]+, 10%), 201 (OPPh2+, 100%). IR
(cm-1): 1576, 1592 (pyridine). 31P{1H} NMR (121.5 MHz,
applied to asymmetric homogeneous catalysis by transition
metal complexes.6 Their interest lies in the fact that if the
ligand is coordinated in a tridentate meridional geometry,
the quadrant effect is enhanced in octahedral catalytic
intermediates, and the substrate undergoes a close interaction
with the chiral substituents of the ligand.
As part of our project on the design and application of
trifunctional ligands, we report hereafter the synthesis of the
pyridinediphosphinite 1 as a novel mixed-P,N-donor ligand
and the study of its complexation behavior toward plati-
num(II).
1
CDCl3): δ 116.7 (s). H NMR (300 MHz, CDCl3) δ 4.95 (d, 4H,
3JHP ) 9.3 Hz, CH2), 7.2-7.7 (m, 23H, Har).
Synthesis of Compound 2. A solution of 1 (1.00 g, 1.97 mmol)
in 30 mL of dichloromethane was slowly added at room temperature
to a solution of PtCl2(PhCN)2 (0.930 g, 1.97 mmol) in 50 mL of
dichloromethane. The yellow solution was stirred at room temper-
ature for 1.5 h and filtered. After concentration of the solution to
ca. 50 mL and slow addition of pentane, complex 2 precipitated as
a white powder (1.04 g, 68% yield). It could be recrystallized from
dichloromethane/pentane. Anal. Calcd for C62H54Cl4N2O4P4Pt2: C,
48.14; H, 3.52; N, 1.81. Found: C, 48.01; H, 3.35; N, 1.84. IR
(cm-1): 295, 318 (Pt-Cl), 1576, 1594 (pyridine). 31P{1H} NMR
(121.5 MHz, CD2Cl2): δ 84.7 (s, 1JPPt ) 4201 Hz). 1H NMR (300
Experimental Section
General Procedures. All experiments were carried out under a
nitrogen or argon atmosphere, using a vacuum line or Vacuum
Atmospheres glovebox equipped with a Dri-Train HE-493 inert gas
purifier. Pentane and THF were distilled over sodium and ben-
zophenone, toluene over sodium, and dichloromethane over calcium
hydride under nitrogen immediately before use. 2,6-Bis(hydroxy-
methyl)pyridine (Aldrich) and n-butyllithium (Fluka, 1.6 M solution
in hexanes) were used as received. Diphenylchlorophosphane (95%
min., Strem) was distilled at 170 °C under reduced pressure and
3
MHz, CD2Cl2) δ 4.85 (d, 8H, JHP ) 6.1 Hz, CH2), 6.84 (d, 4H,
3JHH ) 7.8 Hz, Hpyridine meta), 7.34-7.80 (m, 42H, Har).
7
stored under argon. PtCl2(PhCN)2 and [Cu(MeCN)4](BF4)8 were
Synthesis of Compound 3. A solution of [Cu(MeCN)4](BF4)
(45 mg, 0.143 mmol) in 3 mL dichloromethane was added dropwise
at room temperature to a white suspension of 2 (0.11 g, 0.071 mmol)
in 10 mL dichloromethane. After addition of half of the copper (I)
solution, the mixture became clear, and then progressively turned
back to a white, cloudy suspension until the end of the addition.
After stirring at RT for 3 h, the suspension was filtered on Celite.
After concentration of the solution and slow addition of pentane,
complex 2 precipitated as a white powder (82 mg, 70% yield). It
could be recrystallized from dichloromethane/pentane. Anal. Calcd
for C62H54B2Cl2F8N2O4P4Pt2: C, 45.14; H, 3.30; N, 1.70; Cl 4.30;
F, 9.21. Found: C, 44.96; H, 3.21; N, 1.83; Cl 4.20; F, 8.78. MS
(FAB+, NBA matrix): m/z 1475.0 ([M - 2BF4]+, 13%), 738.0
([M - 2BF4]2+, 100%), 702.0 (Pt(1), M+, 21%). IR (cm-1): 307
(Pt-Cl), 1575, 1610 (pyridine). 31P{1H} NMR (202.5 MHz,
prepared following reported procedures. The NMR spectra were
recorded at room temperature (unless otherwise indicated) on Bruker
spectrometers. 1H NMR spectra were recorded at 300.16 MHz (AC-
300 instrument) or 500.13 MHz (ARX-500) and referenced to
SiMe4. 31P{1H} (broadband decoupled) were recorded at 121.51
MHz (AC-300) or 202.46 MHz (ARX-500) and referenced to 85%
aqueous H3PO4; for compound 3, the numbering of the phosphorus
atoms refers to the crystallographic structure (Figure 2). The
assignments given are supported by 2D NMR analysis performed
1
on the ARX-500 spectrometer (COSY, H-31P HMQC). FT-IR
spectra were recorded on a Perkin-Elmer 1600 series spectrometer
on KBr pellets. FAB MS spectra and elemental analyses were
carried out by the corresponding facilities at the Fe´de´ration de
Recherche de Chimie, Universite´ Louis Pasteur, Strasbourg.
2
1
Synthesis of 2,6-Bis[(diphenylphosphinyl)oxymethyl]pyridine
(1). A solution of n-BuLi in hexanes (9.44 mL, 15.1 mmol) was
added dropwise at -78 °C to 2,6-bis(hydroxymethyl)pyridine (1.00
g, 7.19 mmol) partly dissolved in 200 mL of THF, leading to a
purple solution. The solution was stirred at -78 °C for 30 min,
and the temperature was raised to 0 °C. PPh2Cl (2.80 mL, 15.1
mmol) was slowly added to the solution via syringe, after which
the solution turned pale yellow. Stirring was maintained at 0 °C
for 30 min and then at room temperature for 3 h. The solution was
DMSO-d6): δ 86.3 (d, 2P, JPP ) 14 Hz, JPPt ) 3870 Hz, P2),
2
1
1
90.0 (d, 2P, JPP ) 14 Hz, JPPt ) 3760 Hz, P1). H NMR (500
MHz, DMSO-d6) δ 5.69 (dd, 2H, 2JHH ) 13.9 Hz, 3JHP ) 31.5 Hz,
H4), 6.28 (d, 2H, JHH ) 14.1 Hz, H2), 6.67 (dd, 2H, JHH ) 13.7
Hz, 3JHP ) 6.7 Hz, H3), 7.28 (dd, 2H, 2JHH ) 14.2 Hz, 3JHP ) 7.5
Hz, H1), 6.70-8.30 (m, 46H, Har).
2
2
Collection of the X-ray Data and Structure Determination
for 2 and 3. The crystal data of 2 were collected on a CAD4-
MACH3 diffractometer and those of 3 on a Kappa CCD diffrac-
tometer, using monochromated Mo KR radiation (λ ) 0.71073 Å).
Details of data collection parameters and refinements results are
listed in Table 1. The structures were solved using direct methods.
Hydrogen atoms were introduced as fixed contributors at calculated
positions (C-H ) 0.95 Å, B(H) ) 1.3 Beqv)), except for the
solvent molecules. Final difference maps revealed no significant
maxima. All calculations were done using the Nonius OpenMoleN
package.9 Neutral atom scattering factor coefficients and anomalous
dispersion coefficients were taken from a standard source.10
(4) (a) Ramdeehul, S.; Barloy, L.; Osborn, J. A.; De Cian, A.; Fischer, J.
Organometallics 1996, 15, 5442-5444. (b) Barloy, L.; Ramdeehul,
S.; Osborn, J. A.; Carlotti, C.; Taulelle, F.; De Cian, A.; Fischer, J.
Eur. J. Inorg. Chem. 2000, 2523-2532. (c) Barloy, L.; Gauvin, R.
M.; Osborn, J. A.; Sizun, C.; Graff, R.; Kyritsakas, N. Eur. J. Inorg.
Chem. 2001, 1699-1707.
(5) (a) Barloy, L.; Ku, S. Y.; Osborn, J. A.; De Cian, A.; Fischer, J.
Polyhedron 1997, 16, 291-295. (b) Rahmouni, N.; Osborn, J. A.; De
Cian, A.; Fischer, J.; Ezzamarty, A. Organometallics 1998, 17, 2470-
2476.
(6) (a) Sablong, R.; Newton, C.; Dierkes, P.; Osborn, J. A. Tetrahedron
Lett. 1996, 37, 4933-4936. (b) Bellemin-Laponnaz, S.; Coleman, K.
S.; Dierkes, P.; Masson, J.-P.; Osborn, J. A. Eur. J. Inorg. Chem. 2000,
1645-1649.
(7) Uchiyama, T.; Toshiyasu, Y.; Nakamura, Y.; Miwa, T.; Kawaguchi,
S. Bull. Chem. Soc. Jpn. 1981, 54, 181-185.
(8) Kubas, G. J. Inorg. Synth. 1979, 19, 90-92.
(9) OpenMoleN, InteractiVe Structure Solution; Nonius B. V., Delft, The
Netherlands, 1997.
(10) Cromer D. T., Waber J. T., International Tables for X-ray Crystal-
lography; The Kynoch Press: Birmingham, 1974; Vol. IV (a) Table
2.2b; (b) Table 2.3.1.
Inorganic Chemistry, Vol. 42, No. 9, 2003 2903