Reactions of cationic piano stool iron complexes containing phosphorus ligands with phosphorus ylide

Article abstract of DOI:10.1021/om9610152

Reactions of PF₆^- salts of cationic piano stool iron complexes with a phosphorus ylide, CH₂PPh₃, were examined. In the reaction of the dicarbonyl complex [Cp(CO)₂FeL]⁺ (L = P(OMe)₃, P(OEt)₃, PPh₂(OMe)), Cp(CO)LFe{C(O)CH=PPh₃} is formed by the nucleophilic attack of the carbene carbon of CH₂PPh₃ on the carbonyl carbon of the complex. In contrast, the reaction of the monocarbonyl complex [Cp(CO)LFe{P(OR)₃}]⁺ (L = P(OMe)₃, R = Me; L = PMe₃, R = Me; L = P(OEt)₃, R = Et) yields Cp(CO)LFe{P(O)(OR)₂} by the Arbuzov-like dealkylation reaction. [Cp(PMe₃)₂Fe{P(OMe)₃}]⁺, having no CO ligand, also exhibits the Arbuzov-like dealkylation reaction under forced conditions. These results indicate that increasing the back donation ability from a central transition metal to a ligand induces a change in the reaction site from a carbonyl carbon in a CO ligand to an α-carbon in a phosphite ligand. In the reaction of [Cp(CO)₂Fe{PPh₂H}]⁺, proton abstraction from the PPh₂H ligand takes place to give a phosphide complex Cp(CO)₂FePPh₂.

Full text of DOI:10.1021/om9610152

1562
Organometallics 1997, 16, 1562-1566
Rea ction s of Ca tion ic P ia n o Stool Ir on Com p lexes
Con ta in in g P h osp h or u s Liga n d s w ith P h osp h or u s Ylid e
Hiroshi Nakazawa,* Yoshiko Ueda, Keiichi Nakamura, and Katsuhiko Miyoshi*
Department of Chemistry, Faculty of Science, Hiroshima University,
Higashi-Hiroshima 739, J apan
Received December 4, 1996X
-
Reactions of PF6 salts of cationic piano stool iron complexes with a phosphorus ylide,
CH2PPh3, were examined. In the reaction of the dicarbonyl complex [Cp(CO)2FeL]+ (L )
P(OMe)3, P(OEt)3, PPh2(OMe)), Cp(CO)LFe{C(O)CHdPPh3} is formed by the nucleophilic
attack of the carbene carbon of CH2PPh3 on the carbonyl carbon of the complex. In contrast,
the reaction of the monocarbonyl complex [Cp(CO)LFe{P(OR)3}]+ (L ) P(OMe)3, R ) Me; L
) PMe3, R ) Me; L ) P(OEt)3, R ) Et) yields Cp(CO)LFe{P(O)(OR)2} by the Arbuzov-like
dealkylation reaction. [Cp(PMe3)2Fe{P(OMe)3}]+, having no CO ligand, also exhibits the
Arbuzov-like dealkylation reaction under forced conditions. These results indicate that
increasing the back donation ability from a central transition metal to a ligand induces a
change in the reaction site from a carbonyl carbon in a CO ligand to an R-carbon in a
phosphite ligand. In the reaction of [Cp(CO)2Fe{PPh2H}]+, proton abstraction from the
PPh2H ligand takes place to give a phosphide complex Cp(CO)2FePPh2.
In tr od u ction
Phosphorus ylides, being one of the most well-
investigated compounds in organic chemistry, have
attracted significant attention in organometallic chem-
istry over the past few decades. The results have been
nicely reviewed.1,2 Although many reactions with phos-
phorus ylides have been reported for most of the
transition metals in the periodic table, a systematic
approach, such as the study of an influence of changing
ancillary ligands on a certain transition metal on the
reactivity or reaction site, seems rather sparse. In the
case of cationic piano stool iron complexes, the reactions
of [CpFe(CO)2L]+ (Cp ) η5-C5H5, L ) CO, PPhMe2,
PMe3) with CH2dPR3 have been examined and it was
found that the carbene carbon of CH2dPR3 nucleo-
philically attacks the carbonyl carbon of [CpFe(CO)2L]+
to give [Cp(CO)LFe-C(O)CH2PR3]+, which reacts suc-
cessively with another CH2dPR3 to give Cp(CO)LFe-
C(O)CHdPR3 (eq 1).3 However, the reaction of cationic
piano stool iron complexes containing phosphite with a
phosphorus ylide has not been reported so far. It is well-
known that cationic complexes containing phosphite
react with a nucleophile to give a phosphonate complex
by the Arbuzov-like dealkylation reaction.4,5 We also
have been engaged in the study of piano stool Fe and
Ru complexes with a phosphonate ligand.6 Since CH2PR3
is a very nice nucleophile, two plausible reactions are
expected when cationic piano stool iron complexes
containing phosphite are treated with CH2PR3: (i) a
carbonyl attack, as shown in eq 1, and (ii) an Arbuzov-
like dealkylation reaction to give a phosphonate com-
plex. In order to elucidate which type of reactions take
place for what kind of complexes, we examined the
reaction of several kinds of cationic piano stool iron
complexes containing phosphite with a phosphorus
ylide.
Resu lts a n d Discu ssion
The phosphorus ylide used in this paper is con-
-
fined to CH2PPh3. PF6 salts of several kinds of cat-
ionic piano stool iron complexes are subjected to the
reaction with CH2PPh3, which can be classified into
three groups: [Cp(CO)2FeL]+, [Cp(CO)FeLL′]+, and
[CpFeLL′2]+. The spectroscopic data of the starting
complexes and products are summarized in Table 1.
-
R ea ct ion of [Cp (CO)2F eL]+. A PF6 salt of
[Cp(CO)2Fe{P(OMe)3}]+, 1a , was suspended in benzene,
and 2 equiv of CH2PPh3 was added. The color of the
solution immediately changed from yellow to reddish
orange. After work up, a yellow powder was isolated.
The product was assigned to [Cp(CO){P(OMe)3}Fe-
{C(O)CHdPPh3}] (2a , eq 2) for the following reasons:
(i) The IR spectrum exhibits one absorption at 1914
cm-1 in the νCO region, which is more than 100 cm-1
lower in frequency than those for the starting complex
(2071 and 2028 cm-1), indicating that the product has
one terminal CO ligand and is electrically neutral. (ii)
X Abstract published in Advance ACS Abstracts, March 1, 1997.
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S0276-7333(96)01015-1 CCC: $14.00 © 1997 American Chemical Society

Cationic Piano Stool Iron Complexes
Organometallics, Vol. 16, No. 8, 1997 1563
The Cp* analogue of 1a (1d ) showed the same
reactivity indicating that the carbonyl carbon is still the
reaction site, though the electrophilicity of the CO seems
to be reduced by a more electron-donating Cp* ligand
than a Cp ligand.
R ea ct ion of [Cp (CO)F eLL′]+. For the monocar-
bonyl complexes [Cp(CO)FeLL′]+ (L ) L′ ) P(OMe)3
(3a ); L ) P(OMe)3, L′ ) PMe3 (3b); L ) L′ ) P(OEt)3
(3c)), it is expected that the electrophilicity of the
carbonyl carbon is reduced compared with that of the
dicarbonyl complexes [Cp(CO)2FeL]+. Actually, the
ν
CO’s of 3a -c are considerably lower in frequency than
those for 1a -d (see Table 1).
In the 31P NMR spectrum, two resonances are observed
The reaction of 3a with CH2PPh3 under similar
reaction conditions to those of 1a resulted in the
formation of a yellow powder in 86% yield. The spec-
troscopic data of the product indicate the formation of
Cp(CO){P(OMe)3}Fe{P(O)(OMe)2} (4a , eq 3). The 31P
at 2.02 and 189.05 ppm as doublets with J PP ) 9.2 Hz.
1
(iii) The H and 13C NMR spectra are consistent with
the existence of a -C(O)CHdPPh3 ligand. The elemen-
tal analysis data also support the formation of 2a .
Although the isolation yield was 49%, the conversion
of 1a into 2a proceeded cleanly, which was evidenced
by the IR and 31P NMR measurements of the reaction
mixture. Two more dicarbonyl complexes [Cp(CO)2FeL]-
PF6 (L ) P(OEt)3 (1b), PPh2(OMe) (1c)) were subjected
to the reaction with CH2PPh3. The products were 2b
and 2c, respectively (see eq 2). These results show that
the carbonyl carbon in [Cp(CO)2FeL]+ is the most
reactive site toward CH2PPh3.
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NMR spectrum showed two doublets at 123.95 and
181.91 ppm with J PP ) 137.8 Hz. These are reasonably
attributed to P(O)(OMe)2 and P(OMe)3 ligands, respec-
1
tively. In the H and 13C NMR spectra, two diastereo-
topic OMe groups in the P(O)(OMe)2 ligand were
observed, indicating that the iron is a chiral center and
the racemization either does not occur or is slow on the
NMR time scale. Complexes 3b and 3c were also
converted into the corresponding phosphonate com-
plexes, 4b and 4c, respectively, by the reaction with
CH2PPh3 (eq 3).
These results show that the reactions proceed by the
nucleophilic attack of the carbene carbon of CH2PPh3
at the R-carbon in the coordinating phosphite rather
than at the coordinating CO carbon to give the corre-
sponding phosphonate complexes (the Arbuzov-like
dealkylation reaction). This is the first example in
which a phosphorus ylide induces the Arbuzov-like
dealkylation reaction leading to a transition-metal-
phosphonate complex. It has been reported that CO
ligands with a CO stretching frequency at 2000 cm-1
or above will be subjected to nucleophilic attack to give
+
M-C(O)CH2PPh3 rather than substitution to give
+ 2,7
M-CH2-PPh3
.
Likewise, complexes with carbonyl
stretching modes below 2000 cm-1 appear to give
substitution products. This rule holds in our case in
the sense that complexes 1a-d, having carbonyl stretch-
ing modes above 2000 cm-1, suffer nucleophilic attack
at CO and complexes 3a -c, having νCO below 2000
cm-1, do not sustain nucleophilic attack. The latter
complexes undergo the Arbuzov-like dealkylation reac-
tion rather than the CO substitution.
(6) (a) Nakazawa, H.; Morimasa, K.; Kushi, Y.; Yoneda, H. Or-
ganometallics 1988, 7, 458. (b) Nakazawa, H.; Morimasa, K.; Yoneda,
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8, 2851. (g) Nakazawa, H.; Kadoi, Y.; Itoh, T.; Mizuta, T.; Miyoshi, K.
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1994, 473, 243. (j) Nakazawa, H.; Kubo, K.; Tanisaki, K.; Kawamura,
K.; Miyoshi, K. Inorg. Chim. Acta 1994, 222, 123. (k) Nakazawa, H.;
Miyoshi, K. Trends Organomet. Chem. 1994, 1, 295.
R ea ct ion of [Cp F eLL'2]+. We chose [CpFe-
{P(OMe)3}(PMe3)2]PF6 (5a ) as an example of cationic
piano stool complexes containing no carbonyl ligand and
(7) Angelici, R. Acc. Chem. Res. 1972, 5, 335.

1564 Organometallics, Vol. 16, No. 8, 1997
Nakazawa et al.
Ta ble 1. Sp ectr oscop ic Da ta
IR (CH2Cl2)
1H NMR
(CDCl3) δ (ppm)
31P NMR
complex ν(CO), (cm-1
)
(CH2Cl2) δ (ppm)a
13C NMR (CDCl3) δ (ppm)
1a
2071, 2028
3.84 (d, J PH ) 12.2 Hz, 9H, 159.80 (s, P(OMe)3)
54.85 (d, J PC ) 7.9 Hz, P(OMe)3), 87.19 (s, Cp),
206.82 (d, J PC ) 39.1 Hz, CO)
OMe), 5.43 (s, 5H, Cp)
1b
2068, 2025
1.38 (t, J HH ) 6.9 Hz, 9H,
152.70 (s, P(OEt)3)
15.87 (d, J PC ) 6.7Hz, OCH2CH3), 64.77 (d, J PC )
CH3), 4.16 (qui, J HH
7.1 Hz, 6H, OCH2),
5.39 (s, 5H, Cp)
)
7.9 Hz, OCH2CH3), 87.15 (s, Cp), 207.20 (d, J PC
39.1 Hz, CO)
)
)
1c
2061, 2020
3.64 (d, J PH ) 12.8 Hz, 3H, 164.91 (s, PPh2(OMe))
56.35 (d, J PC ) 9.3 Hz, P(OMe)3),b 89.60 (s, Cp),
130.49 (d, J PC ) 11.2 Hz, m-Ph), 132.05 (d, J PC
11.8 Hz, o-Ph), 134.00 (d, J PC ) 2.5 Hz, p-Ph),
134.52 (d, J PC ) 55.3 Hz, ꢀ-Ph), 209.93 (d, J PC )
27.3 Hz, CO)
OMe),b 5.54 (d, J PH
1.7 Hz, 5H, Cp),
)
7.64-7.78 (m, 10H, Ph)
1d
1e
2047, 2001
2061, 2016
1.90 (s, 15H, Cp*), 3.82
(d, J PH ) 10.4 Hz, 9H,
OMe)
160.19 (s, P(OMe)3)
32.59 (s, PHPh2)
9.47 (s, C5(CH3)5), 55.72 (d, J PC ) 8.7 Hz, P(OMe)3),
100.89 (s, C5(CH3)5), 209.93 (d, J PC ) 36.0 Hz, CO)
5.65 (d, J PH ) 2.0 Hz, 5H,
89.68 (s, Cp),b 130.43 (d, J PC ) 54.1 Hz, ꢀ-Ph), 131.15
(d, J PC ) 11.2 Hz, m-Ph), 133.60 (d, J PC ) 2.5
Hz, p-Ph), 133.62 (d, J PC ) 10.6 Hz, o-Ph),
210.31 (d, J PC ) 24.2 Hz, CO)
Cp),b 7.56 (d, J PH
410.8 Hz, 1H, PH),
)
7.49-7.59 (m, 6H, Ph),
7.67-7.75 (m, 4H, Ph)
2a
2b
1914d
1913d
3.62 (d, J PH ) 10.8 Hz, 9H, 2.02 (d, J PP ) 9.2 Hz,
51.99 (d, J PC ) 4.6 Hz, OMe),c 60.16 (dd, J PC ) 73.1
OMe),c 4.55 (d, J PH
)
PPh3), 189.05 (d, J PP
) 9.2 Hz, P(OMe)3)
and 10.1 Hz, CHdP), 84.77 (s, Cp), 128.46 (d, J PC
9.2 Hz, m-Ph), 130.51 (d, J PC ) 86.4 Hz, ꢀ-Ph),
131.04 (d, J PC ) 2.8 Hz, p-Ph), 133.41 (d, J PC ) 10.1
Hz, o-Ph), 221.49 (dd, J PC ) 49.2 and 3.7 Hz, CO),
230.06 (dd, J PC ) 31.7 and 10.1 Hz, C(O)CH)
)
38.0 Hz, 1H, CHdP),
4.75 (d, J PH ) 0.8 Hz,
5H, Cp), 7.00-7.25
(m, 15H, Ph)
1.15 (t, J HH ) 7.0 Hz, 9H,
1.80 (d, J PP ) 9.8 Hz,
PPh3), 184.07 (d, J PP
) 9.8 Hz, P(OEt)3)
16.60 (d, J PC ) 6.6 Hz, OCH2CH3),c 59.85 (dd, J PC
)
CH3),c 4.15 (qui, J HH
)
71.7 and 8.1 Hz, CHdP), 60.50 (d, J PC ) 8.8 Hz,
OCH2CH3), 84.86 (s, Cp), 128.40 (d, J PC ) 12.4 Hz,
m-Ph), 130.60 (d, J PC ) 86.4 Hz, ꢀ-Ph), 131.00 (d,
J PC ) 2.9 Hz, p-Ph), 133.37 (d, J PC ) 9.5 Hz, o-Ph),
211.82 (dd, J PC ) 50.0 and 2.9 Hz, CO), 230.06 (dd,
J PC ) 31.5 and 10.2 Hz, C(O)CH)
7.0 Hz, 6H, OCH2), 4.55
(d, J PH ) 37.8 Hz, 1H,
CHdP), 4.74 (s, 5H, Cp),
7.02-7.16 (m, 9H, Ph),
7.72-7.78 (m, 6H, Ph)
2c
1902d
3.49 (d, J PH ) 12.3 Hz, 3H, 2.25 (d, J PP ) 6.7 Hz,
52.80 (s, OMe),c 60.94 (dd, J PC ) 70.9 and 6.8 Hz,
CHdP), 85.95 (s, Cp), 127.83 (d, J PC ) 5.6 Hz, m-Ph
in PPh2(OMe)), 128.54 (d, J PC ) 11.8 Hz, m-Ph in
OMe),c 4.43 (s, 5H, Cp),
4.62 (d, J PH ) 37.0 Hz,
1H, CHdP), 6.82-7.15,
7.64-7.70, 8.02 (m,
30H, Ph)
PPh3), 182.05 (d, J PP
) 6.7 Hz, PPh2(OMe))
PPh3), 129.47 (s, p-Ph in PPh3), 130.38 (d, J PC
)
86.4 Hz, ꢀ-Ph in PPh3), 131.11 (d, J PC ) 2.5 Hz, p
Ph in PPh2(OMe)), 132.21 (d, J PC ) 11.2 Hz, o-Ph in
PPh2(OMe)), 133.35 (d, J PC ) 9.9 Hz, o-Ph in PPh3),
141.78 (d, J PC ) 45.4 Hz, ꢀ-Ph in PPh2(OMe)),
142.50 (d, J PC ) 44.1 Hz, ꢀ-Ph in PPh2(OMe)),
222.95 (dd, J PC ) 37.9 and 3.7 Hz, CO), 231.76 (dd,
J PC ) 23.6 and 10.6 Hz, C(O)CH)
2d
1893c
1.86 (s, 15H, Cp*),c 3.69
3.28 (d, J PP ) 11.1 Hz,
PPh3), 185.04 (d, J PP
) 11.1 Hz, P(OMe)3)
9.93 (s, C5(CH3)5),c 52.00 (d, J PC ) 5.3 Hz,
P(OMe)3), 57.80 (dd, J PC ) 70.2 and 9.2 Hz, CHdP),
94.03 (s, C5(CH3)5), 128.17 (d, J PC ) 11.4 Hz, m-Ph),
130.79 (d, J PC ) 3.1 Hz, p-Ph), 130.80 (d, J PC ) 86.2
Hz, ꢀ-Ph), 133.54 (d, J PC ) 9.9 Hz, o-Ph), 223.57 (dd,
J PC ) 45.0 and 5.3 Hz, CO), 239.57 (dd, J PC ) 32.8
and 9.9 Hz, C(O)CH)
(d, J PH ) 10.5 Hz, 9H,
OMe), 4.44 (d, J PH
)
39.4 Hz, 1H, CHdP),
7.10, 7.73, 7.88 (m,
15H, Ph)
3a
3b
1999
1986
3.76 (vt, J PH ) 5.8 Hz,
18H, OMe), 5.03
(s, 5H, Cp)
169.07 (s, P(OMe)3)
53.99 (vt, J PC ) 4.0 Hz, OMe), 84.54 (s, Cp), 212.41
(d, J PC ) 40.3 Hz, CO)
1.18 (d, J PH ) 10.8 Hz, 9H, 30.52 (d, J PP ) 98.4
20.41 (d, J PC ) 34.2 Hz, PMe3),b 54.37 (d, J PC ) 8.7
Hz, P(OMe)3), 85.32 (s, Cp), 215.26 (dd, J PC ) 40.4
and 28.0 Hz, CO)
CH3),b 3.38 (d, J PH
)
Hz, PMe3), 170.90 (d,
J PP ) 98.4 Hz,
P(OMe)3)
11.0 Hz, 9H, OCH3),
5.20 (dd, J PH ) 1.1 and
1.7 Hz, 5H, Cp)
3c
4a
1996
1967
1.28 (t, J HH ) 6.6 Hz, 18H, 162.87 (s, P(OEt)3)
16.06 (vt, J PC ) 3.1 Hz, P(OCH2CH3)3), 63.34 (d,
J PC ) 4.4 Hz, P(OCH2CH3)3), 84.74 (s, Cp), 212.83
(t, J PC ) 41.0 Hz, CO)
CH3), 4.02 (vt, J HH
)
3.3 Hz, 12H, OCH2),
4.89 (s, 5H, Cp)
3.55 (d, J PH ) 11.2 Hz, 3H, 123.95 (d, J PP ) 137.8,
49.86 (d, J PC ) 9.2 Hz, P(O)(OMe)2), 50.05 (d, J PC
9.2 Hz, P(O)(OMe)2), 52.68 (d, J PC ) 5.5 Hz,
)
P(O)(OMe)2), 3.56 (d,
J PH ) 10.8 Hz, 3H,
P(O)(OMe)2), 3.73 (d,
J PH ) 11.2 Hz, 9H,
P(OMe)3), 4.80
P(O)(OMe)2), 181.91
(d, J PP ) 137.8 Hz,
P(OMe)3)
P(OMe)3), 83.81 (s, Cp), 216.29 (t, J PC ) 43.2 Hz,
CO)
(s, 5H, Cp)
4b
1945d
1.51 (d, J PH ) 10.1 Hz, 9H, 35.91 (d, J PP ) 106.8
CH3), 3.51 (d, J PH
10.6 Hz, 3H, OMe), 3.53
(d, J PH ) 10.8 Hz, 3H,
OMe), 4.63 (s, 5H, Cp)
20.28 (d, J PC ) 31.7 Hz, PMe3), 49.19 (d, J PC ) 8.7
Hz, OMe), 50.08 (d, J PC ) 7.5 Hz, OMe), 83.09 (s,
Cp), 217.28 (dd, J PC ) 43.5 and 29.8 Hz, CO)
)
Hz, PMe3), 128.42 (d,
J PP ) 106.9 Hz,
P(O)(OMe)2)

Cationic Piano Stool Iron Complexes
Organometallics, Vol. 16, No. 8, 1997 1565
13C NMR (CDCl3) δ (ppm)
Ta ble 1 (Con tin u ed )
IR (CH2Cl2)
1H NMR
(CDCl3) δ (ppm)
31P NMR
complex ν(CO), (cm-1
)
(CH2Cl2) δ (ppm)a
4c
1963
1.21 (t, J HH ) 7.3, 3H,
P(O)(OCH2CH3)2), 1.25
(t, J HH ) 7.3 Hz, 3H,
P(O)(OCH2CH3)2), 1.30
(t, J HH ) 7.3 Hz, 9H,
P(OCH2CH3)3), 3.95
(qui, J HH ) 7.3 and 7.3
Hz, 4H, P(O)(OCH2CH3)2),
4.06-4.18 (m, 6H,
P(OCH2CH3)3), 4.75
(s, 5H, Cp)
121.05 (d, J PP ) 137.3
Hz, P(O)(OEt)2),
175.67 (d, J PP) 137.3
Hz, P(OEt)3)
16.18 (d, J PC ) 7.4 Hz, P(OCH2CH3)3), 16.75 (d, J PC
) 6.4 Hz, P(O)(OCH2CH3)2), 58.26 (d, J PC ) 9.1 Hz,
P(O)(OCH2CH3)2), 61.44 (d, J PC ) 5.5 Hz,
P(OCH2CH3)3), 84.07 (s, Cp), 216.84 (t, J PC ) 43.2
Hz, CO)
5a
6a
1.43 (vt, J PH ) 4.4 Hz,
18H, PMe3), 3.72 (d,
J PH ) 10.6 Hz, 9H,
P(OMe)3), 4.39 (s,
5H, Cp)
1.31 (t, J PH ) 4.4 Hz,
18H, PMe3), 3.44 (d,
J PH ) 9.9 Hz, 6H,
P(O)(OMe)2), 4.04
(s, 5H, Cp)
27.54 (d, J PP ) 100.7
Hz, PMe3), 177.94 (t,
J PP ) 100.7 Hz,
P(OMe)3)
22.26 (vt, J PC ) 15.2 Hz, PMe3), 53.20 (d, J PC ) 9.3
Hz, P(OMe)3), 79.57 (s, Cp)
34.14 (d, J PP ) 112.9
Hz, PMe3), 143.60 (t,
J PP ) 112.9 Hz,
22.42 (t, J PC ) 13.7 Hz, PMe3), 49.09 (d, J PC ) 9.2
Hz, P(O)(OMe)2), 78.28 (s, Cp)
P(O)(OMe)2)
7e
8e
2008,d 1956
2031,d 1983
8.77 (s, PPh2)d
32.72 (d, J PB ) 61.5
Hz, PPh2)
1.29 (q, J BH ) 96.5 Hz,
3H, BH3),b 5.07 (s, 5H,
Cp), 7.23 (s, 4H, Ph),
7.58 (s, 6H, Ph)
88.25 (s, Cp),b 128.72 (d, J PC ) 8.7 Hz, m-Ph),
129.69 (d, J PC ) 1.9 Hz, p-Ph), 133.54 (d, J PC ) 8.1
Hz, o-Ph), 140.92 (d, J PC ) 28.0 Hz, ꢀ-Ph), 214.10 (d,
J PC ) 18.6 Hz, CO)
a
-
For 1a -e, 3a -c, and 5a , a septet at -143.80 ppm with J PP ) 711.0 Hz due to PF6 was observed in addition to the resonance(s)
shown in the table. In acetone-d6. c In C6D6. In C6H6.
b
d
examined the reaction with CH2PPh3. The result is
depicted in eq 4, showing the Arbuzov-like dealkylation
reaction takes place, though refluxing is required to
promote the reaction. This shows that an R-carbon of
the CO ligands toward CH2PPh3, which serves, in this
reaction, as a Lewis base rather than a nucleophile.
the coordinating P(OMe)3 in 5a still serves as an
electrophilic active site toward a carbene carbon of
CH2PPh3, though the electrophilicity is surely reduced
compared with that for 3a -c. The electrophilic prop-
erty of an R-carbon of 5a has been demonstrated in the
reaction with KOH in the presence of dibenzo-18-
crown-6 under benzene refluxing conditions to give 6a
by the Arbuzov-like dealkylation reaction.6j
Rea ction of [Cp (CO)2F e(P P h 2H)]P F 6 (1e). 1e
belongs to the category of [Cp(CO)2Fe(phosphine)]+ and
has similar νCO absorptions to those of 1a -c. Therefore,
1e may be expected to react with CH2PPh3 at the CO
ligand. However, 1e did not undergo the reaction shown
in eq 1. The product in this reaction was a phosphide
complex, 7e (eq 5). Although 7e is too reactive to be
isolated as a solid, the formation was confirmed by the
comparison of its IR spectrum with that reported in the
literature.8 For further confirmation, 7e was converted
into an isolable metallaphosphine borane by addition
of BH3. 8e that was thus isolated was fully character-
ized. This is the first example in which a phosphorus
ylide creates a transition-metal-phosphide complex.
The reaction shows that the P-H is more reactive than
Con clu sion
Reactions of cationic piano stool iron complexes,
[Cp(CO)2FeL]+, [Cp(CO)FeLL′]+, and [CpFeLL′2]+, with
CH2PPh3 were examined. On going from [Cp(CO)2-
FeL]+ to [Cp(CO)FeLL′]+, the electrophilic site changes
from a CO carbon to an R-carbon in the phosphite
ligand. One of the reasons may come from the number
of reactive ligands: 1a -d have two CO ligands and one
phosphite while 3a and 3c have one CO and two
phosphites. Another reason, which seems to be more
important, is that the electrophilicity of a CO ligand is
much more sensitive to the electron density of a central
metal than that of an R-carbon in phosphite is. The
reaction of 3b, having one CO and one phosphite, with
CH2PPh3 shows that a phosphite is more attractive than
a CO toward a phosphorus ylide. A phosphite is still a
reactive site in 5a , which has two electron-donating
PMe3 ligands. The reaction of 1e revealed that a P-H
is more reactive than a CO ligand toward CH2PPh3.
Exp er im en ta l Section
(8) (a) Burckett-St, J . C. T. R.; Haines, L. R. J .; Nolte, C. R.; Steen,
N. D. C. T. Inorg. Chem. 1980, 19, 577. (b) Ashby, M. T.; Enemark, J .
H. Organometallics 1987, 6, 1323.
Gen er a l Rem a r k s. All reactions were carried out under
an atmosphere of dry nitrogen by using standard Schlenk tube

1566 Organometallics, Vol. 16, No. 8, 1997
Nakazawa et al.
techniques. Column chromatography was performed quickly
in the air. Benzene, pentane, ether, and hexane were purified
by distillation from sodium/benzophenone. These solvents
were stored under an N2 atmosphere. Other solvents, as
eluents of column chromatography, were used without further
purification. CH2PPh3 was obtained in the reported method.9
Complexes 1a ,6j 1c,6h 1e,10 and 5a 6j were prepared according
to the literature methods.
in vacuo to give 2a as a yellow powder (196 mg, 0.34 mmol,
49%). Anal. Calcd for C29H30FeO5P2: C, 60.44; H, 5.25.
Found: C, 60.56; H, 5.13.
P r ep a r a tion of 2b fr om 1a . 2b was prepared from 1b in
the same manner as that of 2a (yield 59%). Anal. Calcd for
C
32H36FeO5P2: C, 62.15; H, 5.87. Found: C, 62.02; H, 5.88.
P r ep a r a tion of 2c fr om 1c. 2c was prepared from 1c in
the same manner as that of 2a . This complex was purified
IR spectra were recorded on a Shimadzu FTIR-8100A
spectrometer. 1H, 13C, and 31P NMR spectra were measured
on a J EOL EX-270, EX-400, or LA-300 spectrometer. 1H and
13C NMR data were referenced to Si(CH3)4 as an internal
standard. 31P NMR data were referenced to 85% H3PO4 as
an external standard. Elemental analyses were performed on
a Perkin-Elmer 2400CHN elemental analyzer.
from benzene/pentane (1/4) (yield 28%). Anal. Calcd for
C
39H34FeO3P2: C, 70.07; H, 5.13. Found: C, 69.87; H, 5.22.
P r ep a r a tion of 2d fr om 1d . 2d was prepared from 1d in
the same manner as that of 2a . The complex was purified
from benzene/pentane (1/4) (yield 38%). Anal. Calcd for
C
34H40FeO5P2: C, 63.17; H, 6.24. Found: C, 63.19; H, 5.99.
P r ep a r a tion of 4a fr om 3a . CH2PPh3 (307 mg, 1.11 mmol)
P r ep a r a tion of 1b a n d 1d . 1b and 1d were synthesized
in a manner similar to that for 1a . For 1b, yield 96%. Anal.
Calcd for C13H20F6FeO5P2: C, 31.99; H, 4.13. Found: 32.19;
H, 4.12. For 1d , yield 54%. Anal. Calcd for C15H24F6FeO5P2:
C, 34.91; H, 4.69. Found: C, 35.01; H, 4.69.
was added to a suspension of 3a (407 mg, 0.74 mmol) in
benzene (4 mL). After the reaction mixture was stirred at
room temperature for 24 h (or was alternatively refluxed for
6 h), the solvent was removed under reduced pressure and the
residue was loaded on a silica gel column. After a few yellow
bands that eluted with acetone were discarded, a yellow band
that eluted with acetone/EtOH (1/1) was collected and the
solvent was removed under reduced pressure. The yellow oil
thus formed was suspended in ether, and removal of the
solvent in vacuo resulted in a yellow powder of 4a (244 mg,
0.64 mmol, 86%). Anal. Calcd for C11H20FeO7P2: C, 34.58;
H, 5.28. Found: C, 34.48; H, 5.19.
P r ep a r a tion of 4b fr om 3b. 4b was prepared from 3b in
the same manner as that of 4a (yield 72%). The complex was
so hygroscopic that the correct elemental analysis data could
not be obtained, though satisfactory spectroscopic data were
obtained.
P r ep a r a tion of 3a . Although 3a has been prepared,11 we
employed the following method. P(OMe)3 (0.26 mL, 2.20 mmol)
was added to a suspension of 1a (942 mg, 2.11 mmol) in
ClCH2CH2Cl (20 mL), and the reaction mixture was refluxed
for 5 h. The solvent was removed under reduced pressure,
and the residue was dissolved in a small amount of CH2Cl2
and loaded on a silica gel column. The yellow band that eluted
with CH2Cl2/acetone (4/1) was collected. Removal of the
solvent in vacuo resulted in the formation of a yellow powder
of 3a (1092 mg, 2.01 mmol, 95%). Anal. Calcd for
C
12H23F6FeO7P3: C, 26.59; H, 4.28. Found: C, 26.77; H, 4.18.
P r ep a r a tion of 3b. AlCl3 (1000 mg, 7.5 mmol) and
P(OMe)3 (1.3 mL, 11.0 mmol) were added to a solution of CpFe-
(CO)(PMe3)Cl (962 mg, 3.69 mmol) in benzene (80 mL). A dark
green oil was immediately formed. The oil that separated from
the supernatant was treated with H2O (40 mL) and NH4PF6
(700 mg, 4.29 mmol). Then, CH2Cl2 (50 mL) was added to the
solution. The organic layer was dried with MgSO4, concen-
trated under reduced pressure, and loaded on a silica gel
column. The yellow band that eluted with CH2Cl2/acetone (3/
1) was collected. Removal of the solvent yielded a yellow
powder, which was washed with ether and dried in vacuo to
give 3b (970 mg, 1.96 mmol, 53%). Anal. Calcd for
P r ep a r a tion of 4c fr om 3c. CH2PPh3 (502 mg, 1.82 mmol)
was added to a suspension of 3c (685 mg, 1.10 mmol) in
benzene (13 mL), and the reaction mixture was refluxed for 2
days. After purification in the same manner as that of 4a , a
yellow powder of 4c (312 mg, 0.67 mmol, 61%) was obtained.
The complex was so hygroscopic that the correct elemental
analysis data could not be obtained, though satisfactory
spectroscopic data were obtained.
P r ep a r a tion of 6a fr om 5a . 6a was prepared from 5a in
the same manner as that of 4a . In this case, refluxing the
benzene solution for 6 h was required to complete the reaction
(yield 91%). Anal. Calcd for C13H29FeO3P3: C, 40.86; H, 7.65.
Found: C, 40.93; H, 7.71.
C
12H23F6FeO4P3: C, 29.17; H, 4.69. Found: C, 29.20; H, 4.62.
P r ep a r a tion of 3c. P(OEt)3 (0.86 mL, 5.02 mmol) was
added to a solution of [Cp(CO)2Fe(THF)]PF6 (897 mg, 2.28
mmol) in CH2Cl2 (30 mL), and the solution was stirred at room
temperature for 24 h. After concentration under reduced
pressure, the solution was loaded on a silica gel column and
eluted with CH2Cl2. The first-eluted orange band and the
second-eluted red band were discarded, and the third-eluted
yellow band was collected. Removal of the solvent in vacuo
resulted in the formation of a yellow powder of 3c (919 mg,
1.47 mmol, 64%). Anal. Calcd for C18H35F6FeO7P3: C, 34.52;
H, 5.63. Found: C, 34.82; H, 5.67.
P r ep a r a tion of 2a fr om 1a . CH2PPh3 (437 mg, 1.58 mmol)
in benzene (4 mL) was added dropwise to a suspension of 1a
(307 mg, 0.69 mmol) in benzene (6 mL), which immediately
caused the color of the solution to change from light yellow to
reddish orange. After the solution was stirred at room
temperature for 8 h, the reaction mixture was filtered. The
solvent was removed from the filtrate under reduced pressure.
The residue was washed with pentane several times and dried
P r ep a r a tion of 8e fr om 1e. CH2PPh3 (80 mg, 0.29 mmol)
was added to a suspension of 1e (137 mg, 0.27 mmol) in
benzene (7 mL), and the reaction mixture was stirred at room
temperature for 30 min. Then BH3‚THF (0.32 mL of a 1.07
M BH3‚THF solution, 0.32 mmol) was added to the solution,
and the solution was stirred at room temperature for 30 min,
causing the color of the solution to change from red to yellow.
After the solvent was removed under reduced pressure, the
residue was loaded on a silica gel column. After elution with
benzene, a yellow band that eluted with benzene/CH2Cl2 (1/1)
was collected and the solvents were removed under reduced
pressure. The residue was redissolved in CH2Cl2 (1 mL), and
then hexane (20 mL) was added. The solvents were removed
in vacuo to give 8e as a yellow powder (67 mg, 0.18 mmol,
66%). Anal. Calcd for C19H18BFeO2P: C, 60.69; H, 4.82.
Found: C, 60.62; H, 4.55.
Ack n ow led gm en t. This work was supported by a
Grant-in-Aid for Scientific Research (No. 07404037)
from the Ministry of Education, Science, Sports and
Culture of J apan.
(9) Schmidbaur, H.; Fu¨ller, H.-J . Angew. Chem., Int. Ed. Engl. 1976,
15, 501.
(10) Nakazawa, H.; Kubo, K.; Kai, C.; Miyoshi, K. J . Organomet.
Chem. 1992, 439, C42.
(11) Schumann, H. J . Organomet. Chem. 1985, 293, 75.
OM9610152