Reactions of mer-Mo(H)(CO)(NO)(PMePh2)3
Organometallics, Vol. 16, No. 11, 1997 2341
was then fitted to a frit assembly under argon counterflow.
The whole assembly was evacuated, the volume of solution was
reduced to 5 mL, and Et2O (∼5 mL) was added to this solution
by vacuum transfer. Hexane (10 mL) was then added to cause
a sticky dark brown solid to precipitate. The mixture was
filtered, and the filtrate was removed under vacuum.. The
residue was extracted with a minimum amount of Et2O, and
then [(CH3)3Si]2O was added to precipitate the yellow-brown
solids. The product was filtered and washed with [(CH3)3Si]2O.
The sticky dark brown solids were subsequently extracted with
Et2O, and the extract was worked up by the same method
described above. The process was repeated five times to give
an overall yield of 0.28 g (58.5 %) of 4. Anal. Calcd for
C33H39NO2P2Mo: C, 61.97; H, 6.15; N, 2.19. Found: C, 61.78;
H, 6.09; N, 1.89. 1H NMR (C6D6): δ 7.70-7.53 (m, 8 H, Ph),
P r ep a r a t ion of m er -Mo{η2-C(O)CH 2CH 2CH 3}(NO)-
(P MeP h 2)3 (5) a n d m er -Mo{η2-C(O)CH (CH 3)2}(NO)-
(P MeP h 2)3 (6). A 30 mg (0.04 mmol) sample of 3 was placed
in a 5 mm sealable NMR tube along with 0.4 mL of C6D6. The
tube was placed on a vacuum line via a needle valve adapter.
The contents were frozen at -196 °C, and then propylene
(0.048 mmol) was condensed from a calibrated volume onto
the frozen solution. The tube was sealed under vacuum and
the contents were allowed to thaw at room temperature. The
tube was then heated at 50 °C, and the reaction was periodi-
cally monitored by 1H and 31P NMR spectroscopies over a
period of a few days. Complex 3 was slowly consumed, and
two new compounds 5 and 6 were formed. After two days,
the maximum yield of 5 and 6 was ∼60% (5:6 ∼ 3:2).
Prolonged heating could not drive the reaction to completion
and higher pressure of propylene resulted in increased de-
composition. The two isomers could not be separated, and
attempts to isolate these compounds free from the starting
hydride 3 were unsuccessful. For 5: 1H NMR (C6D6, aryl
protons omitted): δ 2.56 (t, 2 H, CH2, 3J HH ) 7.7 Hz), 1.42 (m,
2
7.19-6.92 (m, 12 H, Ph), 2.18-2.16 (dm, 2 H, C2H4, J HH ) 9
2
Hz), 1.99 (t, 6 H, PCH3, J PH ) 2.6 Hz), 1.95 (t, 2 H, CH2,
2
3J HH ) 7.3 Hz), 1.89-1.86 (dm, 2 H, C2H4, J HH ) 9 Hz), 1.54
3
3
(hept, 2 H, MoCH2, J HH ) 7.3 Hz, J PH ) 14.6 Hz), 1.02 (q, 2
3
3
H, CH2, J HH ) 7.3 Hz), 0.11 (t, 3 H, CH3, J HH ) 7.3 Hz).
3
3
31P{1H} NMR (C6D6): δ 35.6 (s). 13C{1H} NMR (C6D6):
δ
2 H, CH2, J HH ) 7.6 Hz), 0.61 (t, 3 H, CH3, J HH ) 7.5 Hz),
2
2
2
1.51 (t, 6 H, PCH3, J PH ) 2.6 Hz), 1.48 (d, 3 H, PCH3, J PH
)
)
234.8 (s, CO), 47.0 (s, CH2), 39.2 (t, C2H4, J CP ) 3.1 Hz), 33.2
(s, CH2), 15.9 (t, CH2, J CP ) 12.1 Hz), 13.4 (t, PCH3, J CP
5.1 Hz). 31P{1H} NMR (C6D6): δ 26.3 (t, PMePh2(cis), J PP
2
2
1
)
12.2 Hz), 22.1 (d, PMePh2(trans), J PP ) 12.2 Hz). For 6: 1H
NMR (C6D6, aryl protons omitted): δ 2.30 (hept, 1 H, CH, 3J HH
) 7.3 Hz), 0.95 (d, 6 H, CH3, 3J HH ) 7.3 Hz), 1.57 (t, 6 H, PCH3,
2
11.4 Hz), 6.8 (s, CH3). IR: ν(CO) ) 1640 (m); ν(NO) ) 1520
(s) cm-1
.
tr a n s-Mo{CH 2CH 213C(O)CH 2CH 3}(C2H 4)(NO)-
(P MeP h 2)2 ([13C]-4 was analogously prepared from [13C]-3.
IR: ν(CO) ) 1620; ν(NO) ) 1520 cm-1. tr a n s-Mo{CH2CH2C-
3J HH ) 2.5 Hz), 1.49 (d, 3 H, PCH3, J HH ) 5.1 Hz). 31P{1H}
3
2
NMR (C6D6): δ 25.8 (t, PMePh2(cis), J PP ) 12.2 Hz), 20.5 (d,
PMePh2(trans), J PP ) 12.2 Hz). The 13C-labeled compounds
2
(O)C2H42H}(C2H4)(NO)(P MeP h 2)2 (4-d ) was analogously
prepared as a mixture of isomers (see text) from 3-d.
mer-Mo{η2-13C(O)CH2CH2CH3}(NO)(PMePh2)3 ([13C]-5) and
mer-Mo{η2-13C(O)CH(CH3)2}(NO)(PMePh2)3 ([13C]-6) were
formed analogously in the reaction of [13C]-3 with propylene.
13C{1H} NMR of the acyl carbons (C6D6): [13C]-5, δ 307 (qt,
2J CP ) 13.4 Hz); [13C]-6, δ 309 (qt, 2J CP ) 13.4 Hz) assigned by
relative intensities in comparison with 1H data.
Rea ction of 4 w ith CO. A 10 mg (0.016 mmol) sample of
4 and 2 mg of Fe(C5H5)2 (internal standard) were placed in a
5 mm sealable NMR tube attached to a needle valve adapter,
and the assembly was evacuated on a vacuum line. C6D6 (∼0.5
mL) was transferred into the tube, the contents were frozen
at -78 °C, and the tube was charged with 1 atm of CO. The
needle valve above the tube was closed, and then the tube was
frozen in N2(l) and subsequently sealed under vacuum (this
gave a final pressure of ∼2.5 atm of CO). The contents were
allowed to thaw at ambient temperature, and the reaction was
P r ep a r a tion of m er -MoCl(η1-OdCHCH2CH2CH3)(NO)-
(P MeP h 2)3 (7) a n d m er -MoCl{η1-OdCHCH(CH3)2}(NO)-
(P MeP h 2)3 (8). A C6D6 solution of 5 and 6 was placed in a
NMR tube with an open-faced screw cap equipped with a
Teflon-backed septum. Excess anhydrous HCl was added into
1
the tube via a syringe. The H NMR spectrum indicated that
1
periodically monitored by using H NMR spectroscopy. Over
the acyl ligands in 5 and 6 were cleanly transformed by the
acid to give the coordinated aldehyde complexes 7 and 8,
respectively. The resonances of the aldehyde protons are at δ
12.80 for 7 and at δ 12.63 for 8. 31P{1H} NMR (C6D6) for 7: δ
the period of days, several unidentified intermediates ap-
peared, and after three days, complex 4 had completely
disappeared to give 3-pentanone (80%) and C2H4 as the major
organic products.
2
13.7 (d, PMePh2(trans), J PP ) 19.8 Hz), δ -0.4 (t, PMePh2-
2
2
(cis), J PP ) 19.8 Hz); for 8: δ 13.3 (d, PMePh2(trans), J PP
)
Th er m olysis of 4. A sealed-tube NMR experiment was
carried out as described above for the reaction of 4 with CO
except that no carbon monoxide was sealed in the tube with
4. The NMR tube was heated at 70 °C for ∼2 h, during which
time 4 had disappeared to give 3-pentanone (95%) and C2H4
as the major organic products.
2
19.8 Hz), δ -4.3 (t, PMePh2(cis), J PP ) 19.8 Hz).
Rea ction of CO w ith 7 a n d 8 To Give Bu tyr a ld eh yd e
a n d Isobu tyr a ld eh yd e. A C6D6 solution of 7 and 8 was
placed in a sealable NMR tube attached to a needle-valve
adapter. The contents were frozen at -78 °C, and the
assembly was evacuated. The tube was charged with 1 atm
of CO, the needle valve above the tube was closed, and the
tube was frozen in N2(l), and subsequently sealed under
vacuum to give ∼2.5 atm of CO upon thawing. When the
contents were thawed at room temperature, the NMR spectra
were acquired. The 31P{1H} NMR spectrum showed that the
two AB2 spin patterns of 7 and 8 gradually disappeared in
favor of three singlets that grew in at δ 17.5 (complex 9), 15.5
(complex 10), and -26 (free PMePh2). The 1H NMR showed
that two new aldehyde protons appeared at δ 14.45 and 14.35
for 9 and 10, respectively. The spectroscopic data indicated
that one PMePh2 ligand was displaced by the CO ligand in
each complex. Over a 24 h period, a second CO displaced the
aldehyde ligands in complexes 9 and 10 to give 11, butyral-
dehyde, and isobutyraldehyde, identified by comparison to
authentic samples.
Rea ction of 4 w ith H2. The reaction was carried out in a
fashion analogous to that described above (for CO) except that
H2 was sealed in the tube. After 19 days at ambient temper-
ature, 1H NMR spectrum indicated that complex 4 had
completely decomposed to give a 55% yield of 3-pentanol (by
comparison to an authentic sample) and ethane as the major
organic products. 31P{1H} NMR spectroscopy showed many
phosphorus-containing metal products.
Rea ction of 4 w ith HCl. The reaction was monitored in
a fashion analogous to that described above (for CO), except
that a 5 mm NMR tube with an open-faced screw cap equipped
with a Teflon-backed septum was charged with 10 mg (0.016
mmol) of 4 and ∼0.5 mL of C6D6. Excess concentrated HCl-
(aq) was injected into the tube via a syringe, and the tube was
shaken vigorously. The 1H NMR spectrum showed that the
starting material was completely consumed. Black solids
precipitated from solution, and the major organic products,
P r ep a r a t ion
of tr a n s-Mo[P MeP h {C6H 4C(O)CH 2-
1
as determined by H NMR, were 3-pentanone (85%, based on
4) and ethylene.
CH2C6H 4}](NO)(P MeP h 2)2 (12). A 0.50 g (0.662 mmol)
Cheng, Tan-Yun
