Synthesis of a zwitterionic P-coordinated complex with bis(diphenylphosphino)acetylene

Article abstract of DOI:10.1021/om950507w

New cationic, [(Fp)Ph₂PC≡CPPh₂(Fp)²⁺ (1) and [(Fp)Ph₂PC≡CPPh₂]⁺ (2), and anionic, [Fe₃(CO)₉(μ₃-CCH₃)(Ph ₂PC≡CPPh₂)]^- (3) and [{Fe₃(CO)₉μ₃-CCH₃)} ₂(Ph₂PC≡CPPh₂)]_2- (4), P-coordinate complexes with bis(diphenylphosphino)acetylene have been prepared. The zwitterionic P-coordinated iron complex [{Fe₃(CO)₉-CCH₃)}Ph ₂PC≡CPPh₂(Fp)] (5) has been synthesized in two different ways and characterized by X-ray crystallography.

Full text of DOI:10.1021/om950507w

468
Organometallics 1996, 15, 468-471
Syn th esis of a Zw itter ion ic P -Coor d in a ted Com p lex w ith
Bis(d ip h en ylp h osp h in o)a cetylen e
Elmostafa Louattani and J oan Suades*
Departament de Qu´ımica, Edifici C, Universitat Auto`noma de Barcelona,
08193 Bellaterra, Spain
K. Urtiaga, M. I. Arriortua, and X. Solans
Departament de Cristallografia, Mineralogia i Dipo`sits Minerals, Universitat de Barcelona,
Martı´ i Franque´s s/ n 08028 Barcelona, Spain
Received J une 29, 1995X
Summary: New cationic, [(Fp)Ph2PCtCPPh2(Fp)]2+ (1)
and [(Fp)Ph2PCtCPPh2]+(2), and anionic, [Fe3(CO)9(µ3-
the phosphonioboratoalkynes [Ph2(CH3)PCtCBR3]6 and
the complex [Br(CO)4MnCtCPPh3].7 Furthermore, the
preparation of the ionic complexes [(Fp)Ph2PCtCPPh2]+
and [Fe3(CO)9(µ3-CCH3)(Ph2PCtCPPh2)]- seemed of
interest due to their potential in synthesizing Ph2-
PCtCPPh2 bridged mixed polynuclear compounds.
The reactions performed in the synthesis of the
reported complexes are presented in Scheme 1. All
prepared complexes were identified by the usual ana-
lytical and spectroscopic techniques. The cationic com-
plexes [(Fp)Ph2PCtCPPh2(Fp)]2+ (1) and [(Fp)Ph2-
PCtCPPh2]+ (2) were prepared3 by the simple expedient
of oxidizing 1 or 0.5 mol of [Fe2(CO)4Cp2] with ferroce-
nium in the presence of the diphosphine. The symmetry
and asymmetry around the CtC bond in complexes 1
and 2 are shown clearly by the IR and 31P NMR spectra
of both complexes. The infrared spectrum of 2 shows
one band assigned to ν(CtC) at 2104 cm-1, which is
absent from complex 1. The 31P NMR spectrum of 2
shows a signal at 46.5 ppm that is assigned to the
phosphorus atom coordinated to an iron atom,3 and
another signal at -27.3 ppm is assigned to the unco-
ordinated phosphorus atom. In contrast, only one signal
assigned to the coordinated phosphorus atoms at 46.1
ppm is observed in the 31P NMR spectrum of 1.
The anionic complexes [PPh4][Fe3(CO)9(µ3-CCH3)(Ph2-
PCtCPPh2)] (3) and [PPh4]2[{Fe3(CO)9(µ3-CCH3)}2(Ph2-
PCtCPPh2)] (4) were also prepared4 by the simple
method of adding 1 or 2 mol of the cluster [HFe3(CO)9-
(µ3-η2-CdCH2)]- to 1 mol of the diphosphine. Like
complexes 1 and 2, the symmetry and asymmetry of
complexes 3 and 4 are shown clearly by their IR and
31P NMR spectra. In the IR spectra, the characteristic
band assigned to ν(CtC) is observed only in complex 3
(2124 cm-1); in the 31P NMR spectra, two signals (δ )
-31.2, 43.9 ppm) and one signal (δ ) 43.0 ppm) are
observed for complexes 3 and 4, respectively.
CCH3)(Ph2PCtCPPh2)]- (3) and
[{Fe3(CO)9(µ3-
CCH3)}2(Ph2PCtCPPh2)]2- (4), P-coordinate complexes
with bis(diphenylphosphino)acetylene have been pre-
pared. The zwitterionic P-coordinated iron complex
[{Fe3(CO)9(µ3-CCH3)}Ph2PCtCPPh2(Fp)] (5) has been
synthesized in two different ways and characterized by
X-ray crystallography.
The reactivity of phosphinoalkynes Ph2PCtCR with
polynuclear transition metal compounds has been stud-
ied extensively. The reaction through the phosphine
and the alkyne function is usually observed,1 but some
P-coordinated complexes have been reported where the
alkyne function is uncoordinated.2 In a recent study,3
we reported the synthesis of the cationic P-coordinated
complexes [(Fp)Ph2PCtCR]+ (Fp ) CpFe(CO)2), in
which significant π(CtC) bond polarization was postu-
lated to be a consequence of the phosphorus atom
charge. In an earlier paper,4 we also reported the
synthesis of the anionic P-coordinated complexes [Fe3-
(CO)9(µ3-CCH3)(Ph2PCtCR)]-. These results prompted
an attempt to prepare a zwitterionic complex by means
of the bis(diphenylphosphino)acetylene (Ph2PCtCPPh2).
To our knowledge, this diphosphine has been used to
prepare symmetrical binuclear and polynuclear P-
coordinated complexes,5 but in no case did the groups
bonded to phosphorus atoms have different charges, and
the only related zwitterionic compounds reported are
X Abstract published in Advance ACS Abstracts, November 15, 1995.
(1) (a) Nucciarone, D.; MacLaughlin, S. A.; Taylor N. J .; Carty, A.
J . Organometallics 1988, 7, 106. (b) Sappa, E.; Pasquinelli, G.;
Tiripicchio, A.; Tiripicchio-Camellini, M. J . Chem. Soc., Dalton Trans.
1989, 601. (c) Montllo´, D.; Suades, J .; Dahan, F.; Mathieu, R.
Organometallics 1990, 9, 2933. (d) Imhof, W.; Eber, B.; Huttner, G.;
Emmerich, Ch. J . Organomet. Chem. 1993, 447, 21. (e) Blenkiron, P.;
Taylor, N. J .; Carty, A. J . J . Chem. Soc., Chem. Commun. 1995, 327.
(2) (a) Wong, Y. S.; J acobson, S.; Chieh, P. C.; Carty, A. J . Inorg.
Chem. 1974, 13, 284. (b) Sappa, E.; Predieri, G.; Tiripicchio, A.;
Tiripicchio Camellini, M. J . Organomet. Chem. 1985, 297, 103. (c)
Adams, C. J .; Bruce, M. I.; Horn, E.; Tiekink, E. R. T. J . Chem. Soc.,
Dalton Trans. 1992, 1157. (d) J ohnson, D. K.; Rukachisirikul, T.; Sun,
Y.; Taylor, N. J .; Canty, A. J .; Carty, A. J . Inorg. Chem. 1993, 32, 5544.
(e) Moldes, I.; Ros, J . Inorg. Chim. Acta. 1995, 232, 75.
The zwitterionic complex [{Fe3(CO)9(µ3-CCH3)}Ph2-
PCtCPPh2(Fp)] (5) was prepared in two different ways
(Scheme 1): by reaction between the cationic complex
2 and the anionic cluster [HFe3(CO)9(µ3-η2-CdCH2)]- or
by reaction between the anionic complex 3 and [Fe2(CO)4-
Cp2] in the presence of ferrocenium cation. Spectro-
scopic methods show that the products obtained by
either method are identical, and their formulations
agree with the title complex 5. However, the yields from
(3) Louattani, E.; Lledo´s, A.; Suades, J .; Alvarez-Larena, A.; Piniella,
J . F. Organometallics 1995, 14, 1053.
(4) Louattani, E.; Suades, J .; Mathieu, R. J . Organomet. Chem. 1991,
421, 335.
(5) (a) Carty, A. J .; Efraty, A.; Ng, T. W.; Birchall, T. Inorg. Chem.
1970, 9, 1263. (b) (c) Orama, O. J . Organomet. Chem. 1986, 314, 273.
(d) Sappa, E. J . Organomet. Chem. 1988, 352, 327. (e) Amoroso, A. J .;
J ohnson, B. F. G.; Lewis, J .; Massey, A. D.; Raithby, P. R.; Wong, W.
T. J . Organomet. Chem. 1992, 440, 219.
(6) Bestmann, H. J .; Behl, H.; Bremer, M. Angew. Chem., Int. Ed.
Engl. 1989, 28, 1219.
(7) Goldberg, S. Z.; Duesler, E. N.; Raymond, K. N. Inorg. Chem.
1972, 6, 1397.
0276-7333/96/2315-0468$12.00/0 © 1996 American Chemical Society

Notes
Organometallics, Vol. 15, No. 1, 1996 469
Sch em e 1
is very similar to that reported in the cationic complex
[(Fp)Ph2PCtCPh][BF4]3 [Fe-P ) 2.207(1) Å; P-C(sp)
) 1.746(3) Å; Fe-C(CO) ) 1.785(3) Å; Fe-C(CO) )
1.787(4) Å]. Furthermore, the IR spectrum of 5 shows
two intense bands at 2056 and 2029 cm-1, which are
assigned to the νCO stretching vibrations of the {Fp}
fragment, and similar values are observed in the IR
spectra of the cationic complexes [(Fp)Ph2PCtCPh][BF4]
(2061, 2020 cm-1)3 and [(Fp)PPh3]+ (2070, 2025 cm-1).8
For comparison, the positions of the νCO bands in the
neutral Fe(0) complexes [(η4-C8H8)Fe(CO)2(PPh3)] (1970,
1920 cm-1) show a decrease of 80-100 cm-1, with
respect to the cationic complexes, in agreement with the
charge influence on the metal to carbonyl back-bonding.8
This result agrees with the description of complex 5 as
a zwitterionic compound in which the diphosphine is
bonded to a cationic {Fp}+ fragment. In addition, the
anionic nature of the fragment {Fe3(CO)9(CCH3)} is
supported by the spectroscopic and structural param-
eters of 5. The Fe-C bond distances of the ethylidyne
ligand µ3-CCH3 and the triple-bridging CO ligand are
very similar to those found in the related anionic
complex [PPh4][Fe3(CO)9(µ3-CO)(µ3-CCH3)].9 Further-
F igu r e 1. View of the molecular structure of complex 5a
together with the atomic numbering scheme. The phenyl
rings have been omitted.
the two methods were very different: 85% in the first
and 15% in the second. The very low yield in the
synthesis of 5 from complex 3 may be related with to
competitive oxidation of the anionic complexes by means
of the ferrocenium cation.
In the crystals of complex 5, there are two crystallo-
graphically independent complexes (even if very similar
labeled as 5a and 5b) and two independent water
molecules. The structure of 5a , with the atom number-
ing system adopted, is shown in Figure 1, and selected
bond distances and angles are shown in Table 1 .
The structures of 5a and 5b consist of a diphosphine
ligand Ph2PCtCPPh2 simultaneously bonded to the
fragments {Fp} and {Fe3(CO)9(CCH3)} by two Fe-P
bonds. The structure of the fragment {Ph2PFe(CO)2Cp}
1
more, similar H and 13C NMR resonances are observed
in the related complexes [PPh4][Fe3(CO)9(µ3-CO)(µ3-
CCH3)] [δ(ppm): 1H 4.18 (CH3); 13C 44.3 (CH3), 221.8
(CO), 289.0 (Fe3C)]9 and [PPh4][Fe3(CO)9(µ3-CCH3)Ph2-
PCtCPh] [δ(ppm): 1H 4.2 (CH3); 13C 43.3 (CH3), 225.1
(CO), 283.6 (Fe3C)].4
It is interesting to note that the fragment PsC-
(12)sC(13)sP(2) is not linear, since the angles P(1)sC-
(8) Riley, P. E.; Davis, R. E. Organometallics 1983, 2, 286.
-
(9) Lourdichi, M. Etude de la reactivite de [HFe3(CO)11
]
vis a vis
de l’ethylene et des alcynes. These du doctorat de 3eme cycle.
Universite Paul Sabatier, Toulouse, 1983.

470 Organometallics, Vol. 15, No. 1, 1996
Notes
to the phosphorus atom,5e,10a crystal packing effects,10b
or a resonance form with a lone pair in the R-acetylenic
carbon atom.7 We emphasize that some of the more
bent PsCtC angles have just been reported in the
zwitterionic complexes [Br(CO)4MnCtCPPh3]7 (164°)
and [Ph2(CH3)PCtCBPh3]6 (168.9°). These results sug-
gest that a resonance form with a nonbonding pair of
electrons on the acetylenic carbon atom bonded to the
“cationic phosphorus” could be considered. However, we
believe that the differences between the distortion
observed in the zwitterionic complexes and other com-
pounds with the {PsCtC} fragment are too small to
justify any conclusions.
Ta ble 1. Selected X-r a y Bon d Dista n ces (Å) a n d
An gles (d eg) w ith Esd ’s in P a r en th eses for 5a a n d
5b
5a
5b
Fe(1)-Fe(2)
Fe(1)-Fe(3)
Fe(2)-Fe(3)
Fe(1)-C(1)
Fe(2)-C(1)
Fe(3)-C(1)
Fe(1)-C(3)
Fe(2)-C(3)
Fe(3)-C(3)
Fe-C(COterminal)a,b
C(1)-C(2)
2.522(1)
2.554(1)
2.533(1)
1.968(2)
1.964(4)
1.932(3)
1.983(3)
2.100(3)
2.076(3)
1.779(6)
1.488(6)
1.192(4)
1.135(7)
1.795(3)
1.709(5)
2.097(8)
1.094(4)
1.214(6)
2.211(1)
2.210(1)
1.779(3)
1.750(3)
1.815(3)
1.815(4)
1.822(3)
1.790(4)
1.210(4)
2.535(1)
2.540(1)
2.550(1)
1.963(3)
1.934(4)
1.927(5)
1.992(5)
2.044(5)
2.087(3)
1.761(8)
1.503(7)
1.195(6)
1.15(1)
C(3)-O(3)
C-O(COterminal)a,b
Fe(4)-C(38)
Fe(4)-C(39)
Fe-C(Cp)a
Exp er im en ta l Section
1.800(5)
1.796(4)
2.06(1)
All reactions were performed under nitrogen by standard
Schlenk tube techniques. Infrared spectra were recorded with
a Perkin-Elmer 1710 FT spectrometer using dichloromethane
or acetonitrile solutions. The NMR spectra were recorded by
the Servei de Ressona`ncia Magne`tica Nuclear de la Universitat
Auto`noma de Barcelona on a Bruker AM400 instrument. The
31P chemical shifts are reported in ppm upfield from external
C(38)-O(38)
C(39)-O(39)
Fe(1)-P(1)
1.086(6)
1.095(4)
2.195(1)
2.198(1)
1.747(3)
1.724(3)
1.831(4)
1.816(5)
1.795(4)
1.782(4)
1.250(5)
Fe(4)-P(2)
P(1)-C(12)
P(2)-C(13)
P(1)-C(14)
P(1)-C(20)
P(2)-C(26)
P(2)-C(32)
C(12)-C(13)
1
85% H3PO4. The H and 13C chemical shifts are expressed in
ppm upfield from TMS.
The diphosphine Ph2PCtCPPh2 was prepared by published
procedures.11 Microanalyses were performed by Servei d’Ana`lisi
Qu´ımica de la Universitat Auto`noma de Barcelona.
Fe(1)-Fe(2)-Fe(3)
Fe(2)-Fe(1)-Fe(3)
Fe(1)-Fe(3)-Fe(2)
Fe(1)-C(1)-C(2)
Fe(2)-C(1)-C(2)
Fe(3)-C(1)-C(2)
Fe(1)-C(3)-O(3)
Fe(2)-C(3)-O(3)
Fe(3)-C(3)-O(3)
C(38)-Fe(4)-C(39)
C(38)-Fe(4)-P(2)
C(39)-Fe(4)-P(2)
Fe(1)-P(1)-C(12)
Fe(1)-P(1)-C(14)
Fe(1)-P(1)-C(20)
C(14)-P(1)-C(20)
Fe(4)-P(2)-C(13)
Fe(4)-P(2)-C(26)
Fe(4)-P(2)-C(32)
C(26)-P(2)-C(32)
P(1)-C(12)-C(13)
P(2)-C(13)-C(12)
60.7(1)
59.9(1)
59.5(1)
130.8(2)
133.4(3)
130.2(3)
138.0(2)
129.7(3)
135.2(2)
93.1(2)
59.9(1)
60.3(1)
59.7(1)
128.5(3)
129.8(3)
134.1(2)
136.3(3)
133.7(4)
131.9(3)
95.2(2)
Syn th esis of [(F p )P h 2P CtP P h 2(F p )][BF 4]2 (1). A solu-
tion of [Fe(C5H5)2][BF4] (0.74 g, 2.7 mmol) in dichloromethane
(10 mL) was added to a solution of [Fe2(CO)4Cp2] (0.50 g, 1.4
mmol) and Ph2PCtCPPh2 (0.55 g, 1.4 mmol) in dichlo-
romethane (20 mL). After 2 h of stirring, the solution was
filtered from the precipitated ferrocene and then evaporated
to dryness. The residual oil was washed in light petroleum
(2 × 10 mL) and recrystallized from acetonitrile/diethyl ether
at -20 °C. The yellow crystals that separated were collected,
washed in diethyl ether, and dried in vacuo. Yield: 84%.
91.1(2)
94.3(2)
90.3(2)
92.6(2)
Anal. Calcd for
C
40H30B2F8Fe2O4P2: C, 52.11; H, 3.28.
114.9(1)
117.8(1)
121.6(1)
101.0(1)
109.8(1)
118.4(1)
112.6(1)
106.5(2)
172.1(3)
166.2(3)
113.5(1)
115.0(1)
122.9(1)
101.7(2)
109.1(2)
119.2(1)
115.7(1)
103.0(2)
175.2(4)
169.1(3)
Found: C, 52.33; H, 3.26. IR (CH3CN, cm-1): 2066 (s), 2025
(s) (νCO). 31P NMR (CD3CN): δ 46.1. 1H NMR (CD3CN): δ
5.7 (s, Cp), 7.7 (m, Ph). 13C NMR (CD3CN; except phenyl
resonances): δ 89.4 (s, Cp), 105.1 (dd, J 1 ) 6.1 Hz, J 2 ) 67.1
Hz, tCP), 208.2 (d, J ) 24.6 Hz, CO).
Syn th esis of [(F p )P h 2P CtCP P h 2][BF 4] (2). A solution
of [Fe(C5H5)2][BF4] (0.74 g, 2.7 mmol) in dichloromethane (10
mL) was added to a solution of [Fe2(CO)4Cp2] (0.50 g, 1.4 mmol)
and Ph2PCtCPPh2 (1.10 g, 2.8 mmol) in dichloromethane (20
mL). After 2 h of stirring, the solution was filtered from the
precipitated ferrocene and then evaporated to dryness. The
residual oil was washed in light petroleum (2 × 10 mL) and
recrystallized from dichloromethane/diethyl ether at -20 °C.
The yellow crystals that separated were collected, washed in
diethyl ether, and dried in vacuo. Yield: 79%. Anal. Calcd
for C33H25BF4FeO2P2: C, 60.22; H, 3.83. Found: C, 60.23; H,
3.95. IR (CH2Cl2, cm-1): 2062 (s), 2025 (s) (νCO), 2109 (w)
(νCtC). 31P NMR ((CD3)2CO): δ -27.3 (s, PPh2), 46.5 (s,
FePPh2). 1H NMR ((CD3)2CO): δ 5.7 (s, Cp), 7.7 (m, Ph). 13C
NMR ((CD3)2CO; except phenyl resonances): δ 89.0 (s, Cp),
a
b
Mean value. {Fe3(CO)9(CCH3)} fragment.
Ta ble 2. Cr ysta llogr a p h ic Da ta for 5
formula
FW
space group
a (Å)
b (Å)
C44H28Fe4O11P2‚H2O
1036.04
P1h
12.776(2)
12.856(2)
32.463(4)
87.76(3)
86.86(2)
63.57(2)
4767(2)
4
c (Å)
R (deg)
â (deg)
γ (deg)
V (Å3)
Z
99.3 (d, J ) 91.6 Hz, tCPFe), 117.1 (dd, J 1 ) 34.3 Hz, J 2
7.8 Hz, tCP), 209.1 (d, J ) 20.0 Hz, CO).
)
Dcalcd (g cm-3
)
1.443
13.46
298
Syn th esis of [P P h 4][Fe3(CO)9(µ3-CCH3)(P h 2P CtCP P h 2)]
(3). A solution of Ph2PCtCPPh2 (0.26 g, 0.66 mmol) in acetone
(10 mL) was added to a solution of [PPh4][HFe3(CO)9(µ3-η2-
CdCH2)] (0.50 g, 0.64 mmol) in acetone (20 mL). The resulting
solution was stirred for 16 h, filtered, and evaporated to
µ(Mo KR) (cm-1
T (K)
)
λ (Å)
0.710 69
(12)sC(13) and P(2)sC(13)sC(12) are bent by 6.4° and
12.4°, respectively. Similar distortions have been ob-
served in phosphinoalkynes10 and P-coordinated phos-
phinoalkynes,3 which have been related to nonbonding
interactions between the alkyne and the groups bonded
(10) (a) Bart, J . C. J . Acta Crystallogr., Sect. B 1969, 25, 489. (b)
Yuan, Z.; Taylor, N. J .; Sun, Y.; Marder, T. B.; Williams, I. D.; Cheng,
L. J . Organomet. Chem. 1993, 449, 27.
(11) King, R. B.; Efraty, A. Inorg. Chem. 1969, 8, 2374.

Notes
Organometallics, Vol. 15, No. 1, 1996 471
dryness. The residual oil was crystallized in dichloromethane/
methanol at -20 °C. The red-brown crystals that separated
were collected, washed in cold methanol, and dried in vacuo.
Yield: 75%. Anal. Calcd for C61H43Fe3O9P3: C, 62.07; H, 3.67.
Found: C, 62.14; H, 3.52. IR (CH2Cl2, cm-1): 2023 (m), 1972
(s), 1954 (s) (νCO), 2124 (w) (νCtC). 31P NMR ((CD3)2CO): δ
-31.2 (s, PPh2), 24.1 (s, PPh4), 43.9 (s, FePPh2). 1H NMR
((CD3)2CO): δ 4.2 (s, CH3), 7.7 (m, Ph). 13C NMR ((CD3)2CO;
except phenyl resonances): δ 43.1 (s, CH3), 224.6 (b, CO), 282.1
(s, Fe3C) (the signals for acetylenic carbons could not be
identified).
Syn t h esis of [P P h 4]2[{F e3(CO)9(µ3-CCH3)}2(P h 2P Ct
CP P h 2)] (4). A solution of Ph2PCtCPPh2 (0.25 g, 0.63 mmol)
in acetone (10 mL) was added to a solution of [PPh4][HFe3-
(CO)9(µ3-η2-CdCH2)] (1.00 g, 1.27 mmol) in acetone (20 mL).
The resulting solution was stirred for 16 h, filtered, and
evaporated to dryness. The residual oil was crystallized in
dichloromethane/methanol at -20 °C. The red-brown crystals
that separated were collected, washed in cold methanol, and
dried in vacuo. Yield: 65%. Anal. Calcd for C96H66Fe6O18P4:
C, 58.63; H, 3.38. Found: C, 57.52; H, 3.43. IR (CH2Cl2, cm-1):
2027 (m), 1981 (s), 1963 (s) (νCO). 31P NMR ((CD3)2CO): δ
23.9 (s, PPh4), 43.0 (s, FePPh2). 1H NMR ((CD3)2CO): δ 4.1
(s, CH3), 7.7 (m, Ph). 13C NMR ((CD3)2CO; except phenyl
resonances): δ 42.8 (s, CH3), 224.4 (b, CO), 282.8 (s, Fe3C) (the
signals for acetylenic carbons could not be identified).
Syn t h esis of [{F e3(CO)9(µ3-CCH3)}P h 2P CtP P h 2(F p )]
(5). Meth od a . A solution of 2 (0.25 g, 0.4 mmol) in
dichloromethane (20 mL) was added to a solution of [PPh4]-
[HFe3(CO)9(µ3-η2-CdCH2)] (0.30 g, 0.4 mmol) in dichlo-
romethane (15 mL). The resulting solution was stirred for 24
h, filtered, and evaporated to dryness. The residual oil was
dissolved in dichloromethane, and after the addition of diethyl
ether, a white precipitate of [PPh4][BF4] was formed. The
filtered solution was cooled to -20 °C and red-brown crystals
were obtained, which were collected, washed in diethyl ether,
and dried in vacuo. Yield: 85%.
Anal. Calcd for C44H28Fe4O11P2: C, 51.91; H, 2.77. Found:
C, 51.30; H, 3.17. IR (CH2Cl2, cm-1): 2056 (s), 2029 (s), 1983
(s), 1960 (s), 1956 (s) (νCO), 2125 (w) (νCtC). 31P NMR ((CD3)2-
CO): δ 47.2 (b, PFe(CO)2Cp), 56.4 (b, P{Fe3(CO)9(µ3-CCH3)}).
1H NMR ((CD3)2CO): δ 4.1 (d, J ) 2.3 Hz, CH3), 5.6 (d, J )
1.6 Hz, Cp), 7.7 (m, Ph). 13C NMR ((CD3)2CO; except phenyl
resonances): δ 43.3 (s, CH3), 90.0 (s, Cp), 209.3 (d, J ) 23.5
Hz, Fe(CO)2), 220.2 (b, Fe3(CO)9), 281.4 (s, Fe3C) (the signals
for acetylenic carbons could not be identified).
X-r a y Str u ctu r e Deter m in a tion . A summary of the
crystal data is given in Table 2 . A prismatic crystal (0.1 ×
0.1 × 0.2 mm) was selected and mounted on an Enraf CAD4
diffractometer. Unit cell parameters were determined from
automatic centering of 25 reflections (12 e θ e 16°) and refined
by the least-squares method. Intensities were collected with
graphite-monochromatized Mo KR radiation using the ω-2θ
scan technique. A total of 12 816 reflections was measured
in the range 2 e θ e 30°, 10 000 of which were assumed as
observed by applying the condition I g 2.5σ(I). Three reflec-
tions were measured every 2 h as orientation and intensity
control; significant intensity decay was not observed. Lorentz
polarization but not absorption corrections made.
The structure was solved by Patterson synthesis, using the
SHELXS computer program,12 and refined by the full-matrix
least-squares method with the SHELX76 computer program.13
2
2
2
The function minimized was ∑w| |Fo| - |Fc| | , where w )
σ-2(Fo). f, f ′, and f ′′ were taken from International Tables of
X-ray Crystallography. The final R factor was 0.036 (Rw
)
0.044) for all observed reflections. The number of refined
parameters was 1119. Maximum shift/esd ) 0.1; maximum
and minimum peaks in final difference synthesis were 0.4 and
-0.4 eÅ-3, respectively.
Ack n ow led gm en t. We thank the DGICYT (Projects
PB89-0306 and PB92-0621, Programa de Promocio´n
General del Conocimiento) for financial support.
Meth od b. A solution of [Fe(C5H5)2][BF4] (0.110 g, 0.4
mmol) in dichloromethane (10 mL) was added to a solution of
[Fe2(CO)4Cp2] (0.071 g, 0.2 mmol) and (3) (0.500 g, 0.4 mmol)
in dichloromethane (20 mL). After 2 h of stirring, the solution
was filtered from the precipitated ferrocene and then evapo-
rated to dryness. The residual oil was washed in light
petroleum (2 × 10 mL) and dissolved in dichloromethane, and
after the addition of diethyl ether, a white precipitate of [PPh4]-
[BF4] was formed. The filtered solution was cooled to -20 °C
and red-brown crystals were obtained, which were collected,
washed in diethyl ether, and dried in vacuo. Yield: 15%.
Su p p or tin g In for m a tion Ava ila ble: Tables of atomic
coordinates, anisotropic thermal parameters, and bond lengths
and angles for compound 5 (11 pages). Ordering information
is given on any current masthead page.
OM950507W
(12) SHELXS. Sheldrick, G. M. Acta Crystallogr. 1990, A46, 467-
473.
(13) SHELX 76. Program for Crystal Structure Determination;
Sheldrik, G. M., Ed.; University of Cambridge: Cambridge, England,
1976.