Transition-metal-substituted phosphanes, arsanes and stibanes, LXIII.: Coupling reactions of alkynes with iron coordinated diphenylphosphane: Generation of an alkenylphosphane and a chelating bisphosphane ligand 1

Article abstract of DOI:10.1016/S0022-328X(98)00806-7

The reaction of {Cp(OC)₂[H(Ph)₂P]Fe}BF₄ (1) with acetylenedicarboxylic acid dimethyl ester (2) in the presence of Et₃N followed by addition of HBF₄ leads to the cationic alkenylphosphane complex [Cp(OC)₂Fe-P(Ph)₂-C(CO₂Me)=C(CO ₂Me)H]BF₄ (5). In contrast, the reaction of the bis(diphenylphosphane) complex {Cp(OC)[H(Ph)₂P]₂Fe}BF₄ (6) with 2 yields {Cp(OC)Fe[P(Ph)₂-C(H)(CO₂Me)-C(H)(CO ₂Me)-PPh₂]}BF₄ (7), bearing a functionalised dppe-analogous chelate phosphane. The molecular structures of 5 and 7 are determined by single crystal X-ray analysis.

Full text of DOI:10.1016/S0022-328X(98)00806-7

Journal of Organometallic Chemistry 570 (1998) 107–112
Transition-metal-substituted phosphanes, arsanes and stibanes, LXIII.
Coupling reactions of alkynes with iron coordinated
diphenylphosphane: generation of an alkenylphosphane and a chelating
bisphosphane ligand1
Wolfgang Malisch *, Franz-Josef Rehmann, Heinrich Jehle, Joachim Reising
Institut fu¨r Anorganische Chemie der Uni6ersita¨t Wu¨rzburg, Am Hubland, 97074 Wu¨rzburg, Germany
Received 12 May 1998
Abstract
The reaction of {Cp(OC)2[H(Ph)2P]Fe}BF4 (1) with acetylenedicarboxylic acid dimethyl ester (2) in the presence of Et3N
followed by addition of HBF4 leads to the cationic alkenylphosphane complex [Cp(OC)2Fe–P(Ph)2–C(CO2Me)ꢀC(CO2Me)H]BF4
(5). In contrast, the reaction of the bis(diphenylphosphane) complex {Cp(OC)[H(Ph)2P]2Fe}BF4 (6) with
2 yields
¸¹¹¹¹¹¹¹¹¹¹¹¹¹¹º
{Cp(OC)Fe[P(Ph)2–C(H)(CO2Me)–C(H)(CO2Me)–PPh2]}BF4 (7), bearing a functionalised dppe-analogous chelate phosphane.
The molecular structures of 5 and 7 are determined by single crystal X-ray analysis. © 1998 Elsevier Science S.A. All rights
reserved.
Keywords: Alkyne; Secondary phosphane complexes; P–H bond; Metal-assisted coupling reaction; Vinylphosphane; Chelate
phosphane
usually guarantees the intermediate formation of a
metal phosphido species responsible for the coupling
1. Introduction
[1,3].
Due to the activities in the field of the chemistry of
We now present the results of the reaction between
complexes and metal catalysis, novel phosphane ligands
acetylenedicarboxylic acid dimethyl ester and cationic
are of increasing interest, especially those with stereo-
secondary phosphane iron complexes of the type
genic centers [2]. We focus on selective reactions of
š
š
{Cp(OC)2[H(R)2P]Fe]
and {Cp(OC)[H(R2)P]2Fe} .
P–H units facilitated by coordination to a metal frag-
ment [1]. In addition, this approach promises stereospe-
cific reactions at the metal leading to the introduction
of stereogenic centres into the phosphorus organic
molecule.
Our interest is especially focused on the reaction of the
alkyne with the bisphosphane complex 6, representing
access to the formation of chelate phosphane analogues
of dppe at the metal.
Recently we found an easy insertion of diazoacetic
ester into the P–H bond of cationic secondary phos-
phane iron complexes via the terminal nitrogen. In this
case even the assistance of a base can be omitted which
2. Results
The reaction of the cationic diphenylphosphane iron
complex 1 with the alkyne 2 under addition of Et3N
yields the phosphaferracyclopentenone complex 3 de-
scribed for the first time by Enemark ([4]a). It is
* Corresponding author. Tel.: +49 931 8885277; fax: +49 931
8884618; e-mail: Wolfgang.Malisch@mail.uni-wuerzburg.de
1 Part LXII. See [1].
0022-328X/98/$ - see front matter © 1998 Elsevier Science S.A. All rights reserved.
PII S0022-328X(98)00806-7

108
W. Malisch et al. / Journal of Organometallic Chemistry 570 (1998) 107–112
Scheme 1.
C(CO2Me)ꢀC(H)CO2Me. This process is repeated with
the second diphenylphosphane ligand leading to an
intramolecular attack of the metal-bound phosphido
function at the activated sp2-carbon. Protonation of the
carbanion terminates the reaction sequence.
obvious that deprotonation of 1 affords the ferrio-phos-
phane Cp(OC)2Fe–PPh2 [5] which then couples with 2
in the established [3+2]-cycloaddition fashion [4]. The
originally expected cationic product deriving from a
P–H-insertion of the alkyne, the alkenyldiphenylphos-
phane complex 5 is not observed. Apparently, the acid-
š
ity of the ammonium ion HNEt3 is not sufficient to
cleave the C(O)–CꢀC-bond by protonation of the sp2-
carbon connected to the acyl carbon. However, treat-
ment of 3 with HBF4 (4) leads to an opening of the
2.1. Molecular structures of Z-5 and 7
The central iron atom of the cationic complex salt
Z-{Cp(OC)2Fe[PPh2–C(CO2Me)ꢀC(H)CO2Me)]}BF4
(Z-5) (Fig. 1) shows an octahedral arrangement for the
CO, Cp and phosphane ligands indicated by the corre-
sponding bond angles (C1–Fe1–C2 93.49(18)°, C1–
Fe1–P 93.33(11)°, C2–Fe1–P 90.58(12)°).
metallacycle
3 to produce 5 as a mixture of
diastereomers (E/Z, 72:28) (Scheme 1).
In contrast to 1, the bis(diphenylphosphane) iron
complex 6 reacts with one equivalent of 2 in the pres-
ence of Et3N to yield the functionalized chelate diphos-
phane complex 7 as a yellow microcrystalline powder
(86%) (Scheme 2).
The bond lengths Fe–CO and Fe–P lie within the
˚
expected range (Fe1–C1 1.780(4) A, Fe1–C2 1.782(4)
˚
˚
A [6], Fe–P 2.2334(10) A [7]). The substituents at the
phosphorus exhibit a staggered conformation with re-
spect to the ligands at the metal, but showing a slight
clockwise rotation around the P–Fe1 bond. One of the
two phenyl units adopts the anti-position with respect
to the Cp ligand [Cp(Z)Fe1–P–C10 158.90°], while the
second one (C20–C25) and the alkenyl group are orien-
tated syn to the CO ligands (C20–P–Fe1–C2
144.22(15)°, C30–P–Fe1–C1 171.44(14)°) (Fig. 2).
The substituents at the phosphorus atom show a
distorted tetrahedral arrangement with the largest an-
gles including the metal fragment (C10–P–Fe
These results clearly indicate that the addition of the
P–H unit of the secondary phosphane ligand to the
C–C triple bond is favoured compared with a [3+2]-
cycloaddition involving the carbonyl ligand according
to the reaction of complex 1 which has only one
phosphane coordinated to the metal. Introduction of a
second Ph2PH donor presumably reduces the elec-
trophilicity of the CO carbon atom to such an extent,
that C–C-coupling with the alkyne is prevented.
In the coupling reaction according to Scheme 2, 7 is
exclusively formed as the RR/SS-diastereomers having
the COOMe-groups in an anti-position. Evidence for
this fact is given by the two doublet signals of the
diastereotopic chelate phosphorus atoms in the 31P-
NMR and by the X-ray diffraction study.
114.82(8)°,
C20–P–Fe
115.41(9)°,
C30–P–Fe
113.57(8)°), whereas the angles between the organo
groups are diminished (C10–P–C20 101.79(12)°, C10–
P–C30 104.70(12)°, C20–P–C30 104.62(12)°).
It is suggested that 7 is formed by primary deproto-
The nearly planar alkenyl moiety (C41–C30–C31–
C51 175.5(3)°) is characterized by a CꢀC-double bond
nation of
6
to yield the ferrio-phosphane
˚
Cp(OC)[H(Ph2)P]Fe–PPh2 as an intermediate. Cou-
pling with the alkyne and protonation of the resulting
adduct leads to the alkenyldiphenylphosphane complex
[8] (C30–C31 1.328(4) A) with the two ester units
adopting an E-configuration. Although the two car-
bons involved in the CꢀC-double bond are nearly per-
fectly planar (sum of angles: C30 359.97°, C31 359.9°),
analogue
of
5,
Cp(OC)[H(Ph)2P]Fe–P(Ph)2–

W. Malisch et al. / Journal of Organometallic Chemistry 570 (1998) 107–112
109
Scheme 2.
the individual angles, especially at C31, are quite differ-
ent, showing the higher sterical demand of the CO2Et
group compared with the hydrogen atom H31 (C30–
C31–C51 131.4(3)°, C30–C31–H31 118.9(1.5)°, C51–
C31–H31 109.6(1.5)°).
atom. Although for both phosphorus units a staggered-
conformation is observed, the organo groups at P1
show a counter-clockwise rotation of about 35° around
the P1–Fe1-axis (Cp(Z)–Fe1–P1–C8 143.99°, Cp(Z)–
Fe1–P1–C10 96.26°, Cp(Z)–Fe1–P1–C20 26.96°),
whereas at the P2–Fe1-axis only a 15° clockwise rota-
tion is found (Cp(Z)–Fe1–P2–C7 165.58°, Cp(Z)–
Fe1–P2–C30 76.61°, Cp(Z)–Fe1–P2–C40 48.03°)
(Fig. 4).
The
X-ray
analysis
of
[Cp(OC)-
¸¹¹¹¹¹¹¹¹¹¹¹¹¹¹º
Fe–PPh2CH(CO2Me)CH(CO2Me)PPh2]BF4 (7) (Fig. 3)
shows an octahedral conformation of the Cp, CO and
bisphosphane ligand (C1–Fe1–P2 86.90(11)°, C1–
Fe1–P1 96.26(11)°, P2–Fe1–P1 88.09(3)°).
The substituents at both phosphorus atoms exhibit
distorted tetrahedral arrangements with the smallest
angles between the phenyl units (C10–P1–C20
102.65(14)°, C30–P2–C40 102.93(14)°) and the greatest
ones between the iron centre and the phenyl groups
(Fe1–P1–C10 120.04(10)°, Fe1–P1–C20 114.95(9)°,
Fe1–P2–C30 123.78(10)°, Fe1–P2–C40 112.50(10)°).
The C–C bond of the ethylene moiety showing a
˚
The short Fe1–C1 bond (1.754(4) A) proves a strong
back donation from the metal to the carbonyl group
due to the electron-donating bisphosphane chelate lig-
and [7]. The difference in the Fe–P bond lengths (Fe1–
˚
˚
P2 2.1851(10) A, Fe1–P1 2.2033(10) A) is evoked by
the anti-position of the carboxy groups creating differ-
ent geometries at the carbon and the phosphorus
atoms. This different geometry is also indicated by the
unequal conformations of the substituents at the phos-
phorus atoms with respect to the ligands at the iron
˚
value of 1.521(4) A lies in the range of normal single
˚
bonds [8]. The P1–C8 (1.877(3) A) and P2–C7 dis-
˚
tances (1.865(3) A) are, due to steric reasons, slightly
elongated compared with P–C single bonds [6]. The
torsion angle C71–C7–C8–C8 (−60.2(3)°) proves the
staggered-conformation of the carboxy groups with
respect to the C–C bond with the phosphorus
atoms P1, P2 occupying the ‘trans’ positions to the
CO2Me groups (P1–C8–C7–C71 171.62(18)°, P2–C7–
Fig.
1.
ORTEP
plot
of
{Cp(OC)2Fe[P(Ph)2–
˚
C(CO2Me)ꢀC(H)CO2Me]}BF4 (Z-5). Selected bond lengths (A),
bond and torsion angles (°): Fe1–C1 1.780(4), Fe1–C2 1.782(4),
Fe1–P 2.2334(10), P–C30 1.838(3), C30–C31 1.328(4); C1–Fe1–C2
93.49(18), C1–Fe1–P 93.33(11), C2–Fe1–P 90.58(12), C20–P–Fe1
115.88(10), C10–P–Fe1 114.89(9), C30–P–Fe1 113.65(9), C31–
C30–P 126.7(2), C41–C30–P 119.3(2); C1–Fe1–P–C30 171.88(15),
C2–Fe1–P–C30 −94.59(17), C41–C30–C31–C51 −173.8(3), P–
C30–C31–C51 3.8(5),C31–C30–C41–O41 −23.7(4).
Fig. 2. View along the P–Fe1-axis of Z-5. The anion is omitted for
clarity.

110
W. Malisch et al. / Journal of Organometallic Chemistry 570 (1998) 107–112
is not suitable to exert stereocontrol in coupling reac-
tions. Pseudo-tetrahedral half-sandwich fragments of
the iron type are known to be efficient in this respect as
proved by a series of interesting metal-mediated organic
syntheses [10,11]. Therefore, forthcoming experiments
will be directed towards the synthesis of chelating
diphosphanes with several functional and stereogenic
centres.
3. Experimental section
3.1. General information and instrumentation
All manipulations were carried out under dry N2
using Schlenk techniques. Solvents were rigorously
dried with an appropriate drying agent, distilled before
use and saturated with nitrogen. 1H-, 13C- and 31P-
NMR, Bruker AMX 400; IR, Perkin Elmer, Model
283. Melting points, differential thermal analysis
(DTA), Du Pont 9000.
Fig.
3.
ORTEP
plot
of
[Cp(OC)-
¸¹¹¹¹¹¹¹¹¹¹¹¹¹¹º
Fe–PPh2CH(CO2Me)CH(CO2Me)PPh2]BF4 (7). Selected bond
lengths (A), bond and torsion angles (°): Fe1–C1 1.754(4), Fe1–P2
˚
2.1851(10), Fe1–P1 2.2033(10), P1–C8 1.877(3), P2–C7 1.865(3),
C7–C8 1.521(4); C1–Fe1–P2 86.90(11), C1–Fe1–P1 96.26(11), P2–
Fe1–P1 88.09(3), C8–P1–Fe1 106.99(10), C7–P2–Fe1 104.58(10),
C8–C7–P2 106.47(18), C7–C8–P1 110.82(19); P2–Fe1–P1–C8 −
7.57(9), P1–Fe1–P2–C7 29.74(10), Fe1–P2–C7–C8 −50.78(19),
C71–C7–C8–C81 −60.2(3), P2–C7–C8–P1 46.1(2).
3.2. {(p5-Cyclopentadienyl)(dicarbonyl)[1,2-
di(methylcarboxylato)6inyl-diphenylphosphane]iron(II)}
tetrafluoroborate (5)
A
solution of 245 mg (0.54 mmol) of
{Cp(OC)2[Ph2(H)P]Fe}BF4 (1) and 85 mg (0.60
mmol) of acetylenedicarboxylic acid dimethyl ester (2)
in 12 ml of dichloromethane is treated with 61 mg
(0.60 mmol) of Et3N. The reaction mixture is stirred for
C8–C81 174.33(19)°). The P2–C7–C8–P1 torsion an-
gle (46.1(2)°) verifies a strong distortion of the five-
membered cycle due to the two sp3-hybridized
carbon-atoms involved in the ring system.
The same chelate ligand has been generated by Trei-
chel and Wong [9] starting from neutral fac-
2 d at room temperature and the presence of Cp(OC)-
¸¹¹¹¹¹¹¹¹¹¹¹¹¹¹º
Fe–PPh2–C(CO2Me)ꢀC(CO2Me)C(ꢀO) (3) ([4]a) can
be detected by 31P-NMR. 70 mg (0.80 mmol) of HBF4/
H2O (1:1) (4) are added, and the mixture is stirred for
another 2 d. Volatiles are removed in vacuo and the
residue extracted with 3 ml of acetonitrile. After addi-
tion of 20 ml of ether the formed precipitate is sepa-
rated, washed three times each with 5 ml of ether and
dried in vacuo. Yield 233 mg (73%). Yellow-orange
{Mn(CO)3[P(Ph)2H]2Br}.
But
in
this
case
deprotonation to give the reactive phosphido species
requires n-BuLi. Moreover, this type of metal fragment
crystalline
powder.
M.p.
195°C
(decomp.).
Diastereomeric ratio 72:28. E-5: 1H-NMR ([D3]-ace-
tonitrile, 300.4 MHz): l=7.71–7.42 (m, 10 H, H5C6),
6.65 (s, 1 H, HCꢀC), 5.58 [d, 3J(PFeCH)=1.6 Hz, 5 H,
H5C5], 3.90 (s, 3 H, H3C), 3.79 ppm (s, 3 H,
H3C).31P{1H}-NMR ([D3]-acetonitrile, 121.5 MHz):
l=59.8 ppm (s). IR (acetonitrile): w(CO)=2047 (s),
1
2002 (s); w(CꢀO)=1738 (s) cm−1. Z-5: H-NMR ([D3]-
acetonitrile, 300.4 MHz): l=7.71–7.42 (m, 10 H,
3
H5C6), 6.22 [d, J(PCCH)=15.2 Hz, 1 H, HCꢀC], 5.32
[d, 3J(PFeCH)=1.7 Hz, 5 H, H5C5], 3.73 (s, 3 H, H3C),
3.25 ppm (s, 3 H, H3C). 31P{1H}-NMR ([D3]-acetoni-
trile, 121.5 MHz): l=65.9 ppm (s). IR (acetonitrile):
w(CO)=2047 (s), 2002 (s); w(CꢀO)=1738 cm−1 (s).
C25H22BF4FeO6P (592.07): calcd. C 50.72, H 3.75;
found C 50.12, H 3.32.
Fig. 4. View along the P2–Fe1-axis of 7. The anion is omitted for
clarity.

W. Malisch et al. / Journal of Organometallic Chemistry 570 (1998) 107–112
111
3.3. {[RR/SS1,2-Bis(diphenylphosphino)-1,2-
bis(methylcarboxylato)ethane](carbonyl)
parameters), R1=0.0389, wR2=0.1061. 7: C36H33-
BF4FeO5P2, M=750.22, monoclinic; space group,
(p5-cyclopentadienyl)iron(II)}tetrafluoroborate (7)
˚
˚
P21/n (No. 1014); a=12.537(3) A, b=16.908(6) A,
˚
c=16.620(7) A, h=k=90.00°, i=107.781(14)°,
3
˚
A
solution of 318 mg (0.52 mmol) of
V=3355(2) A , Z=4; CAD4-diffractometer (Enraf-
Nonius); radiation type, Mo–Kh; wavelength, u=
{Cp(OC)[Ph2(H)P]2Fe}BF4 (6) in 15 ml of
dichloromethane is treated with 74 mg (0.52 mmol) of
acetylenedicarboxylic acid dimethyl ester (2) and 20 mg
(0.20 mmol) of Et3N and the mixture is stirred for
3 d at room temperature. The volume of the reaction
mixture is reduced in vacuo to 2 ml. After the addi-
tion of 20 ml of ether, the precipitate is separated,
washed three times each with 5 ml of ether and dried
in vacuo to give 7. Yield 338 mg (86%). Yellow
crystalline powder. M.p. 204°C (decomp.). 1H-NMR
([D3]-acetonitrile, 400.1 MHz): l=7.86–7.24 (m, 20 H,
H5C6), 4.75 [t, 3J(PFeCH)=1.6 Hz, 5 H, H5C5],
4.35–4.25 (m, 2 H, HCCH), 3.29 (s, 3 H, H3CO),
3.14 ppm (s, 3 H, H3CO). 13C{1H}-NMR ([D3]-acetoni-
trile, 100.6 MHz): l=213.5 (s, CO), 168.2 [dd,
2J(PCC)=19.1 Hz, 3J(PCCC)=5.0 Hz, CꢀO], 167.3
[dd, 2J(PCC)=17.1 Hz, 3J(PCCC)=5.0 Hz, CꢀO],
134.9–128.4 (m, C6H5), 52.3 (s, CH3O), 52.1 (s, CH3O),
50.6 [dd, 1J(PC)=21.6 Hz, 2J(PCC)=15.6 Hz,
˚
0.71073 A; graphite monochromator; Dcalc. =1.485 g
cm−3; crystal size, 0.20×0.15×0.15 mm; scale range,
1.76°BUB25.06°; F(000), 1544; temperature, 293(2)
K; total reflections, 8856; observed reflections, 4178
with (I\2.0|I); absorption coefficient v=0.610
mm−1; semiempirical absorption correction (Tmin/Tmax
,
0.8952/0.9999); structure solution, SHELXS-96 [12]
with patterson methods; structure refinement,
SHELXL-96 [13] (489 parameters), R1=0.0385, wR2=
0.0970 [14].
References
[1] Part LXII: W. Malisch, K. Thirase, F.-J. Rehmann, J. Reising,
N. Gunzelmann, Eur. J. Inorg. Chem., in press.
[2] (a) K.M. Pietrusiewicz, M. Zablocka, Chem. Rev. 94 (1994)
1375. (b) H.B. Kagan, M. Sasaki, in: S. Patai, Z. Rappoport
(Eds.), The Chemistry of Organophosphorus Compounds, vol. 1,
Wiley, New York 1990.
[3] (a)W.E. Buhro, B.D. Zwick, S. Georgiou, J.P. Hutchinson, J.A.
Gladysz, J. Am. Chem. Soc. 110 (1988) 2427. (b) W. Malisch, K.
Thirase, J. Reising, J. Organomet. Chem., in press.
[4] (a) M.T. Ashby, J.H. Enemark, Organometallics 6 (1987) 1323.
(b) W.F. McNamara, E.N. Duesler, R.T. Paine, Organometallics
5 (1986) 1747. (c) L. Weber, M. Frebel, R. Boese, Chem. Ber.
128 (1995) 413.
1
2
CH], 49.2 ppm [dd, J(PC)=20.1 Hz, J(PCC)=17.1
Hz, CH]. 31P{1H}-NMR ([D3]-acetonitrile, 162.0
MHz): l=100.4 [d, 2J(PFeP)=43.8 Hz], 96.7 ppm
[d, 2J(PFeP)=43.8 Hz]. IR (acetonitrile): w(CO)=
1983 (vs); w(CꢀO)=1783 (vs) cm−1
. C36H33BF4-
FeO5P2 (750.25): calcd. C 57.63, H 4.43; found C 55.95,
H 4.31.
[5] (a) J.C.T.R. Burckett-St. Laurent, R.J. Haines, C.R. Nolte,
N.D.C.T. Steen, Inorg. Chem. 19 (1980) 577. (b) W. Malisch, A.
Spo¨rl, H. Pfister, J. Organomet. Chem., in press.
[6] L. Sutton (Ed.), Tables of Interatomic Distances and Configura-
tions in Molecules and Ions, Spec. Publ. 11, 18, The Chemical
Society, London, 1965.
[7] L. Pauling, Die Natur der chemischen Bindung, Verlag Chemie,
Weinheim, 1964.
[8] R.C. Weast (Ed.), CRC Handbook of Chemistry and Physics,
59th edn., CRC, Boca Raton, FL, 1978, F-215.
3.4. X-ray analysis of {(p5-cyclopentadienyl)
(dicarbonyl)[(Z-1,2-di(methylcarboxylato)-6inyl)
diphenylphosphane]iron(II)}-tetrafluoroborate (Z-5) and
{[(trans-2,3-bis(diphenylphosphino)butane-1,4-
dicarboxylicdimethylester]-(carbonyl)
(p5-cyclopentadienyl)-iron(II)}tetrafluoroborate (7)
Suitable orange crystals were obtained by slow diffu-
sion of ether into a saturated solution of Z-5 and 7,
respectively, in dichloromethane. 5: C25H22BF4FeO6P;
M=592.06; monoclinic; space group, P21/n (No.
[9] P.M. Treichel, W.K. Wong, J. Organomet. Chem. 157 (1978) 5.
[10] (a) S.G. Davies, Tetrahedron Lett. 27 (1986) 3787. (b) S.G.
Davies, Aldrichimica Acta 23 (1990) 31. (c) H. Brunner, Angew.
Chem. 103 (1991) A-310. (d) H. Brunner, Adv. Organomet.
Chem. 18 (1980) 151.
[11] (a) A. Bader, D.D. Pathak, S.B. Wild, A.C. Willis, J. Chem.
Soc., Dalton Trans. (1992) 1751. (b) A. Bader, Y.B. Kang, M.
Pabel, D.D. Pathak, A.C. Willis, S.B. Wild, Organometallics 14
(1995) 1434. (c) G.T. Crisp, G. Salem, S.B. Wild, F.S. Stephens,
Organometallics 8 (1989) 2360. (d) E. Hey, A.C. Willis, S.B.
Wild, Z. Naturforsch. 44B (1989) 1041. (e) G. Salem, S.B. Wild,
J. Organomet. Chem. 370 (1989) 33. (f) B.D. Zwick, M.A.
Dewey, D.A. Knight, W.E. Buhro, A.M. Arif, J.A. Gladysz,
Organometallics 11 (1992) 2673. (g) J.A. Gladysz, B.J. Boone,
Angew. Chem. 109 (1997) 566; Angew. Chem. Int. Ed. Engl. 36
(1997) 551.
˚
˚
1014); a=13.691(3) A, b=14.072(5) A, c=14.205(6)
3
˚
˚
A, h=k=90.00°, i=108.251(13)°, V=2599.1(15) A ,
Z=4; CAD4-diffractometer (Enraf-Nonius); radiation
˚
type, Mo–Kh; wavelength, u=0.71073 A; graphite
monochromator; Dcalc. =1.513 g cm−3; crystal size,
0.40×0.30×0.30 mm; scale range, 1.80°BUB24.92°;
F(000), 1208; temperature, 293(2) K; total reflections,
9386; observed reflections, 3389 with (I\2.0|I);
absorption coefficient v=0.709 mm−1; semi-empirical
absorption correction (Tmin/Tmax
,
0.9247/0.9989);
structure solution, SHELXS-96 [12] with patterson
methods; structure refinement, SHELXL-96 [13] (385
[12] G.M. Sheldrick, SHELXS-96, Program for Crystal Structure
Solution, University of Go¨ttingen, 1996.

112
W. Malisch et al. / Journal of Organometallic Chemistry 570 (1998) 107–112
[13] G.M. Sheldrick, SHELXL-96, Program for Crystal Structure
Refinement, University of Go¨ttingen, 1996.
[14] Crystallographic data (excluding structure factors) for the struc-
tures reported in this paper have been deposited with the Cam-
bridge Crystallographic Data Centre as ‘supplementary
publication no. CCDC-101572 and 101573’. Copies of the data
can be obtained free of charge on application to CCDC, 12
Union Road, Cambridge CB2 1EZ (fax: +44 1223 336033;
e-mail: deposit@ccdc.cam.ac.uk).
.