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I. Bachert et al. / Journal of Organometallic Chemistry 580 (1999) 257–264
3.2.5. [Co2Pt(v3-CO)(CO)4(v-dppa)2] (2)
material remained on top of the column that could not
be eluted with THF or CH2Cl2.
Upon addition of dppa (0.070 g, 0.182 mmol) to a
solution of [Co2Pt(CO)7(m-dppa)] (1) (0.163 g, 0.182
mmol) in THF (20 cm3) at room temperature (r.t.), gas
evolution was observed, indicating that a reaction was
occuring. The solvent was removed in vacuo and the
solid was washed with toluene (10 cm3) and n-hexane
(10 cm3), affording a red–brown powder (0.085 g,
38%). (Found: C, 51.83; H, 3.31; N, 2.43.
C53H42Co2N2O5P4Pt requires C, 52.00; H, 3.43; N,
2.29%). IR (THF): w(CO) 1998s, 1967ms, 1950s and
1886s cm−1. NMR (acetone-d6): 1H, l 7.60–6.90 (m, 40
H, aromatic), 6.34 (br–m, 2 H, NH); 31P-{1H}, l 77.6
Complex 4 could not be isolated in pure form and
was characterized in solution by its 31P{1H}-NMR
spectrum (acetone-d6): l 78.7 (br, m, PCodppa), 48.9
(m, PPddppa), 27.55 (br, m, PCodppm), −13.7 (d,
2
PPddppm, J(PP)=34 Hz).
¸¹¹¹¹¹º
3.2.8. [(OC)2Co(v-dppa)2PdCl] (5)
A filtered solution of Na[Co(CO)4] (0.1 M in THF,
2.8 cm3) and [Pd(dppa-P,P%)2](BF4)2 (0.279 g, 0.266
mmol) in THF (20 cm3) was stirred for 2 h at −30°C.
The color of the mixture rapidly turned from light
yellow to brown. After this time LiCl (0.011 g, 0.266
mmol) was added. The solvent was evaporated to dry-
ness under reduced pressure, the residue was extracted
with dichloromethane (20 cm3) and the solution was
filtered through a Celite-padded filter funnel. The sol-
vent was removed in vacuo and the residue was recrys-
tallized from a mixture of THF (15 cm3) and pentane
(60 cm3) at −20°C to afford green–brown microcrys-
talline powder of (5 · THF) (0.155 g, 53% based on Pd).
1
(br, 2 PCo), 56.6 (br, 2 PPt, J(PPt)=3917 Hz).
3.2.6. [Co2Pt(v3-CO)(CO)4(v-dppa)(v-dppm)] (3)
This complex was prepared following a similar proce-
dure to that for complex 2, but starting from
[Co2Pt(CO)7(m-dppa)] (1) (0.500 g, 0.560 mmol) and
dppm (0.216 g, 0.560 mmol). However, it could not be
isolated in pure form and was characterized in solution
by its IR (THF): w(CO) 1997s, 1967s–br, 1950vs and
1885s cm−1, and its 31P{1H}-NMR (acetone-d6): l 76.7
(Found:
C,
58.37;
H,
4.33;
N,
2.58.
1
C50H42PdN2O2P4ClCo · THF requires C, 58.98; H, 4.58;
(br, PCodppa), 54.7 (m, br, PPtdppa, J(PPt)=3973
N, 2.55%). IR (THF): w(CO) 1959vs and 1895s–br
Hz), 26.5 (m, br, PCodppm), 4.0 (m, br, PPtdppm
,
1
cm−1. NMR (acetone-d6): H, l 7.78–7.24 (m, 40H,
1J(PPt)=3584 Hz). Alternatively, complex (3) may be
obtained by reaction of [Co2Pt(m3-CO)(CO)6(m-dppm)]
(0.500 g, 0.560 mmol) with dppa (0.216 g, 0.560 mmol)
under similar conditions.
aromatic), 6.29 (br, 2H, NH), 3.63 and 1.80 (THF
signals); 31P-{1H}, l 82.0 (br, PCo), 63.5 (t, PPd,
N=ꢀJ(PAPX)+J(PAPX%)ꢀ=116 Hz).
3.2.9. [MoPd2ClCp(v2-CO)(v-dppa)2] (6)
3.2.7. [Co2Pd(v3-CO)(CO)4(v-dppa)(v-dppm)] (4)
A filtered solution of Na[Mo(CO)3Cp] · 2DME (0.1
M in THF, 6.8 cm3) was added to a cooled (−78°C)
and stirred suspension of [Pd2Cl2(m-dppa)2] (0.360 g,
0.342 mmol) in 20 cm3 THF. The reaction was progres-
sively raised to ambient temperature while stirring was
maintained for 2 h. The yellow–brown mixture was
filtered to remove insoluble NaCl. The filtrate was
evaporated to dryness and the residue extracted with
CH2Cl2. Precipitation with n-hexane yielded 6 (0.152 g,
62%) contaminated with [Pd2Cl2(m-dppa)2] (25% by
NMR). Attemps to isolate pure 6 were unsuccessful.
A solution of Na[Co(CO)4] (0.1 M in THF, 5 cm3)
was added dropwise to a suspension of [PdCl2(dppm-
P,P%)] (0.140 g, 0.249 mmol) in THF (20 cm3) at
−30°C. The color of the suspension slowly turned
from light yellow to red. After this, solid dppa (0.096 g,
0.25 mmol) was added and the solution was further
stirred for 3 h. The reaction mixture was filtered on a
Celite-padded filter funnel to remove insoluble material,
containing NaCl. The 31P{1H}-NMR spectrum (THF/
acetone-d6) of the reaction mixture revealed the pres-
ence of 4, [Co2Pd(m3-CO)(CO)4(m-dppm)2] and
Data for 6: IR (THF): w(CO) 1795mw and 1745s cm−1
.
[(OC)2C¸o(¹m¹-d¹p¹p¹a)¹2PºdCl] (5). The solution was impreg-
nated on silica gel, evaporated to dryness and the
residue was chromatographed on a silica gel column.
Elution with a mixture of hexane (75%) and toluene
(25%) gave first a pale yellow solution of unreacted
compounds. Elution with a mixture of hexane (25%)
and toluene (75%) afforded a light purple solution of
[Co2Pd(m3-CO)(CO)4(m-dppm)2] [5a] characterized by
IR and 31P{1H}-NMR spectroscopics methods. Elution
with pure toluene afforded a dark purple solution of 5
characterized by IR and 31P{1H}-NMR spectroscopic
methods. Further elution with THF afforded a small
amount of a mixture of 4 and 5. Some dark purple
NMR (acetone-d6): 1H, l 7.48–7.19 (m, 40H, aro-
matic), 6.39 (m, 1H, NH), 6.18 (m, 1H, NH); 31P-{1H},
l 100.2 (m, PMo), 45.1 (m, 2PPd), 42.5 (m,
PPd).
3.2.10. [MoPd2ClCp(v2-CO){v-(Ph2P)2NMe}2] (7)
To a solution of [MoPd2ClCp(m3-CO)(CO)(m-dppa)2]
(6) (0.249 g, 0.201 mmol) in 20 cm3 THF was added an
excess of KH (2 mmol), gas evolution was observed,
indicating that a reaction was occuring. When gas
evolution stopped an excess of MeI (2 mmol) was
added and stirring was maintained for 3 h. After filtra-
tion the solvent was removed in vacuo and the residue
Bachert, Isolde
