A C2-symmetric analogue of dppf: Synthesis and structures of the indenyl-diphosphine complex 1,3-(Ph2PSe)2(C9H6) and the racemic and meso isomers of the heterobimetallic complex Mo(CO)4(1-PPh2-η5-C9H 6)2Fe

Article abstract of DOI:10.1016/S0022-328X(98)01163-2

The preparation, isolation and characterisation of 1,3-bis(diphenylphosphino)indene (1) from indene and chlorodiphenylphosphine is described. The reaction of 1 with selenium gives the diselenide adduct 1,3-bis(diphenylselenophosphino)indene (2) which was characterised crystallographically. Deprotonation of 1 and treatment with ferrous chloride gives the unstable tetraphosphine complex bis(1,3-bis(diphenylphosphino)indenyl)iron(II) (3). Complex 3 decomposes to the diphosphine complex bis(1-diphenylphosphinoindenyl)iron(II) (4) via replacement of one diphenylphosphine substituent per indenyl ligand by a hydrogen atom. Complex 4 was also prepared by treatment of two equivalents of 1-diphenylphosphinoindenide with ferrous chloride. The heterobimetallic complex tetracarbonyl(bis(1-diphenylphosphinoindenyl)iron(II))molybdenum(0) (5) was also prepared and crystal structures of both the meso (5a) and C₂-symmetric racemic (5b) isomers are reported.

Full text of DOI:10.1016/S0022-328X(98)01163-2

Journal of Organometallic Chemistry 580 (1999) 245–256
A C2-symmetric analogue of dppf: synthesis and structures of the
indenyl-diphosphine complex 1,3-(Ph2PSe)2(C9H6) and the racemic and
meso isomers of the heterobimetallic complex
Mo(CO)4(1-PPh2-h5-C9H6)2Fe
Julian J. Adams, David E. Berry, Jane Browning, Dirk Burth, Owen J. Curnow *
Department of Chemistry, Uni6ersity of Canterbury, Pri6ate Bag 4800, Christchurch, New Zealand
Received 20 October 1998
Abstract
The preparation, isolation and characterisation of 1,3-bis(diphenylphosphino)indene (1) from indene and chlorodiphenylphos-
phine is described. The reaction of 1 with selenium gives the diselenide adduct 1,3-bis(diphenylselenophosphino)indene (2) which
was characterised crystallographically. Deprotonation of 1 and treatment with ferrous chloride gives the unstable tetraphosphine
complex bis(1,3-bis(diphenylphosphino)indenyl)iron(II) (3). Complex
3 decomposes to the diphosphine complex bis(1-
diphenylphosphinoindenyl)iron(II) (4) via replacement of one diphenylphosphine substituent per indenyl ligand by a hydrogen
atom. Complex 4 was also prepared by treatment of two equivalents of 1-diphenylphosphinoindenide with ferrous chloride. The
heterobimetallic complex tetracarbonyl(bis(1-diphenylphosphinoindenyl)iron(II))molybdenum(0) (5) was also prepared and crystal
structures of both the meso (5a) and C2-symmetric racemic (5b) isomers are reported. © 1999 Elsevier Science S.A. All rights
reserved.
Keywords: Indenyl-phosphine complexes; Heterobimetallic; Chiral ligands
bridges [3] as well as a number with one- or three-atom
bridges [4,5]. We have reported recently the coordina-
1. Introduction
tion chemistry of the ligand bis(2-cyclopentadi-
enylethyl)phenylphosphine with iron and zirconium [6].
Investigations of indenyl complexes are not as extensive
as their cyclopentadienyl counterparts, even though
they have many of the same properties and are often
more catalytically active due to the ease with which
they can undergo ring-slippage reactions. These
ring-slippage reactions can, however, make the indenyl
complexes more difficult to isolate and characterise.
Little coordination chemistry has been investi-
gated with phosphino-substituted indene and indenyl
ligands. Most complexes are of the indene coordinated
through the phosphorus atom [7–9] and most p-
coordinated systems are with group 4 metals [10].
McGlinchey has reported recently the manganese p-
The use of multifunctional ligands is increasing
rapidly because of their utility in the preparation of
polymetallic complexes in which the metal centres may
exhibit co-operative effects: the polymetallic complex
may behave differently from the sum of the individual
moieties. Phosphines and cyclopentadienyls are two of
the most commonly used classes of ligands because
they are easy to tune and can be functionalised readily.
Most investigations involving tethered cyclopentadi-
enyl-phosphine ligands have the functionalities directly
bound, as in diphenylphosphinocyclopentadienyl [1,2].
There are also many investigations with two-atom
* Corresponding author. Fax: +64-3-3642110.
E-mail address: o.curnow@chem.canterbury.ac.nz (O.J. Curnow)
0022-328X/99/$ - see front matter © 1999 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(98)01163-2

246
J.J. Adams et al. / Journal of Organometallic Chemistry 580 (1999) 245–256
complex {1,3-(Ph2P)2-h5-C9H5}Mn(CO)3 [11]. Diphos-
phine-indenyl ligands are rare and include
McGlinchey’s complex above and the P,P%-coordinated
complex {(1,2-(Ph2P)2)(3-OEt)C9H5}Cr(CO)4 [8].
The complex 1,1%-bis(diphenylphosphino)ferrocene
(dppf) is the most studied complex that contains a
ligand with both phosphine and cyclopentadienyl func-
tionalities [2]. This is because it is also a chelating
diphosphine ligand that provides the ability to rigidly
control two coordination sites and take advantage of
the extra stability imparted through the chelate effect.
Derivatives containing chiral functional groups are be-
ing used in asymmetric synthesis [12], however, C2-sym-
metric systems are very rare [12,13].
In this paper we report the preparation, isolation and
characterisation of 1,3-bis(diphenylphosphino)indene
(1), a selenium adduct of 1, an indenyl analogue of
dppf, of which one isomer has C2 symmetry, and a
heterobimetallic complex utilising this dppf analogue.
Compound 1 has been reported by McGlinchey and
co-workers; however, it was not isolated or character-
ised [11].
The diselenium adduct of 1, 1,3-bis(diphenylse-
lenophosphino)indene (2) is prepared readily by heating
a toluene solution of 1 with selenium (Scheme 1). The
downfield shifts, compared to 1, of the resonances in
the 31P-NMR spectrum (37.9 ppm and 20.9 ppm) and
the observation of one-bond P–Se coupling constants
(750 and 730 Hz, respectively) confirm coordination of
the phosphorus atoms to selenium. The four-bond P–P
coupling constant has increased slightly to 6 Hz. The
corresponding chemical shifts reported for the oxide
and sulfide analogues are 32.0/22.1 ppm and 46.9/32.5
ppm, respectively [11]. McGlinchey and co-workers as-
signed the downfield shifts to the phosphorus atom on
C-1 and the upfield shifts to the phosphorus atom on
C-3 on the basis that l 31P(sp3)\l 31P(sp2). Although
this trend applies to phosphines, and their oxides and
sulfides, the trend is reversed for selenides; thus,
l(Ph3PSe) 34.1\l(Ph2MePSe) 22.3\l(Me3PSe) 8.0
[14]. Therefore, we assign the downfield resonance to
the phosphorus atom on C-3 and the upfield resonance
to the phosphorus atom on C-1. This assignment is also
consistent with the JPSe trend in which JPSe(Ph3PSe)
735.5\1JPSe(Ph2MePSe) 725\1JPSe(Me3PSe) 684 [14].
The molecular structure of 2 was further confirmed
by an X-ray crystallographic analysis. Bond distances
are given in Table 1, selected bond angles in Table 2,
crystal data and structure refinement parameters in
Table 3, and the atomic coordinates and equivalent
isotropic displacement parameters are given in Table 4.
The asymmetric unit contains two crystallographically
independent molecules of 2 along with one molecule of
dichloromethane solvate. Fig. 1 shows a thermal ellip-
soid plot of one of the two molecules with the adopted
numbering scheme. The conformer of the other
molecule is very similar; no torsion angle differs by
more than 10° between the two molecules. The torsion
angles that describe the Se atom orientation are: Se(1)–
1
1
2. Results and discussion
2.1. Diphosphino-indenes
1,3-Bis(diphenylphosphino)indene (1) is prepared
readily in a two-step procedure from indene (Scheme 1)
by, firstly, the sequential addition of one equivalent of
n-BuLi and chlorodiphenylphosphine to give
diphenylphosphinoindene, and, secondly, the addition
of another sequential equivalent of n-BuLi and
chlorodiphenylphosphine. Filtration through alumina,
removal of solvent, and washing with ethanol, in which
it is sparingly soluble, provides 1 in high yield (87%).
Compound 1 has been characterised by 1H-, 13C-,
31P-NMR spectroscopy, microanalysis and EI mass
spectrometry. Two doublets in the 31P-NMR spectrum
at −1.1 ppm and −21.6 ppm are consistent with Ph2P
groups on sp3 and sp2 carbon atoms, respectively, and
are similar to those found for 1-diphenylphosphinoin-
dene (−4.3 ppm) and 3-diphenylphosphinoindene (−
22.3 ppm) [9]. The four-bond P–P coupling constant is
4 Hz. The 13C-NMR spectra of 1 and the other com-
pounds presented herein are discussed in a later section.
P(1)–C(1)–C(2)=58.4(4);
Se(2)–P(2)–C(3)–C(2)=
118.7(4); Se(1%)–P(1%)–C(1%)–C(2%)\48.4(4); Se(2%)–
P(2%)–C(3%)–C(2%)=115.2(4). A comparison with those
found for the oxide and sulfide analogues, which have
very similar conformations to each other, shows that 2
has adopted a different conformation: although the
selenide on C3 has a similar orientation to that of the
oxidised and sulfided analogues (O2–P2–C3–C2=
102.3° and S2–P2–C3–C2=110.6°), the selenide on
C1 is oriented to the other side of the indenyl ring and
away from the C1 hydrogen atom (O1–P1–C1–C2=
−57.0° and S1–P1–C1–C2= −59.9°) [11].
2.2. Complexes of iron
We desired to prepare a complex containing two
diphosphino-indenyl ligands on the one metal centre to
give a tetraphosphine ligand. The indene 1 was depro-
tonated and added to a solution containing one half-
Scheme 1.

J.J. Adams et al. / Journal of Organometallic Chemistry 580 (1999) 245–256
247
Table 1
Selected bond distances (A)
˚
Bond
2
2%
5a
5a%
5b
Mo–P
Fe–C(1)
Fe–C(2)
Fe–C(3)
Fe–C(4)
Fe–C(9)
C(1)–C(2)
C(2)–C(3)
C(3)–C(4)
C(4)–C(5)
C(5)–C(6)
C(6)–C(7)
C(7)–C(8)
C(8)–C(9)
C(1)–C(9)
C(4)–C(9)
P–C(3)
2.5577(14)
2.056(5)
2.041(5)
2.014(6)
2.092(5)
2.095(6)
1.417(8)
1.435(8)
1.457(8)
1.421(8)
1.360(9)
1.416(9)
1.347(8)
1.427(8)
1.430(8)
1.438(8)
1.826(6)
2.5691(15)
2.038(5)
2.014(6)
2.048(5)
2.101(5)
2.100(5)
1.433(8)
1.439(7)
1.456(8)
1.428(8)
1.369(8)
1.401(8)
1.360(8)
1.420(8)
1.432(8)
1.450(7)
1.818(6)
2.5658(7)
2.058(2)
2.071(2)
2.0718(19)
2.1038(19)
2.085(2)
1.426(3)
1.444(3)
1.460(3)
1.435(3)
1.373(3)
1.431(4)
1.355(4)
1.442(3)
1.437(3)
1.452(3)
1.8264(19)
1.514(6)
1.354(6)
1.483(6)
1.386(6)
1.387(7)
1.391(7)
1.405(7)
1.382(6)
1.523(7)
1.416(6)
1.803(4)
1.859(4)
2.1144(14)
2.1251(14)
1.527(6)
1.366(6)
1.475(6)
1.401(7)
1.382(7)
1.388(7)
1.389(7)
1.394(7)
1.512(7)
1.414(6)
1.803(5)
1.862(4)
2.1138(15)
2.1265(14)
P(1)–C(1)
P(1)–Se(1)
P(2)–Se(2)
equivalent of ferrous chloride (Scheme 2); the resultant
solution, before work-up, shows a single peak in the
31P-NMR spectrum at −19.9 ppm which is assigned to
diphenylphosphino group on each indenyl has been
replaced by a hydrogen atom. The 31P-NMR spectrum
of 4 shows a single peak at −22.5 ppm. Steric conges-
tion coupled with facile ring-slippage decomposition
routes are believed to be responsible for the instability
of complex 3.
the
desired
product,
bis(1,3-bis(diphenylphos-
phino)indenyl)iron(II) (3). The 31P-NMR spectrum of
the residue obtained by removing the solvent in vacuo,
however, shows a complex spectrum. Chromatography
The diphosphine 4 was prepared in higher yield
(40%) by treatment of ferrous chloride with two equiva-
lents of [Ph2PC9H6]− (Scheme 2). Complex 4 can exist
in two isomeric forms; a meso form, 4a, and a racemic
form, 4b. Surprisingly, these isomers are chemically and
on
silica
produced
only
bis(1-(diphenylphos-
phino)indenyl)iron(II) (4), in 20% yield, in which one
Table 2
Selected bond angles (A)
˚
1
spectroscopically almost identical. The H-, 13C-, and
31P-NMR spectra suggest only one isomer however, we
have been able to isolate, vide infra, single crystals of a
heterobimetallic complex of 4 containing the meso iso-
mer as well as single crystals containing the racemic
isomer. Whereas the meso isomer exhibits Cs symmetry,
the racemic isomer exhibits C2 symmetry, thus, in each
complex, the indenyl rings are equivalent and they
would be expected to show the same patterns in their
NMR spectra. To date, we have been unable to deter-
mine the racemic:meso ratio using chiral shift reagents.
2
C(1)–P(1)–Se(1)
C(3)–P(2)–Se(2)
C(2)–C(1)–P(1)
C(9)–C(1)–P(1)
C(2)–C(1)–C(9)
C(4)–C(3)–P(2)
C(2)–C(3)–P(2)
C(2)–C(3)–C(4)
113.69(15)
C(1%)–P(1%)–Se(1%) 112.68(15)
C(3%)–P(2%)–Se(2%) 112.10(15)
112.74(14)
110.9(3)
111.5(3)
102.9(4)
123.9(3)
126.3(4)
109.5(4)
C(2%)–C(1%)–P(1%)
C(9%)–C(1%)–P(1%)
C(2%)–C(1%)–C(9%)
C(4%)–C(3%)–P(2%)
C(2%)–C(3%)–P(2%)
C(2%)–C(3%)–C(4%)
109.6(3)
112.6(3)
103.2(4)
125.3(3)
124.8(4)
109.5(4)
5a
Fe–C(3)–P
C(3)–P–Mo
P–Mo–P%
P–C(3)–C(2)
C(2)–C(3)–C(4)
C(4)–C(3)–P
126.7(3)
124.3(2)
98.71(5)
129.8(4)
106.5(5)
123.5(4)
P%–C(3%)–Fe
133.3(3)
117.6(2)
112.5(2)
119.4(4)
106.5(5)
133.1(4)
Mo–P%–C(3%)
C(3)–Fe–C(3%)
P%–C(3%)–C(2%)
C(2%)–C(3%)–C(4%)
C(4%)–C(3%)–P%
2.3. Heterobimetallic iron-molybdenum complexes
To investigate the coordination chemistry of diphos-
phine 4, the tetracarbonylmolybdenum complex
tetracarbonyl(bis(1-diphenylphosphinoindenyl)iron(II))-
molybdenum(0) (5) was prepared in 40% yield by treat-
ment of Mo(CO)4(piperidine)2 with one equivalent of 4.
As with 4, the heterobimetallic complex 5 has racemic
and meso isomers. Curiously, crystals of 5 prepared
5b
Fe–C(3)–P
C(3)–P–Mo
P–Mo–P%
C(3)–Fe–C(3%)
128.97(10)
122.18(6)
99.44(3)
P–C(3)–C(2)
C(2)–C(3)–C(4)
C(4)–C(3)–P
129.54(15)
106.47(16)
123.74(14)
113.64(10)

248
J.J. Adams et al. / Journal of Organometallic Chemistry 580 (1999) 245–256
Table 3
Crystal data and structure refinement parameters for 2, 5a and 5b
Compound
2
5a
5b
Empirical formula
Formula weight
Temperature (K)
C33.5H27ClP2Se2
684.86
158(2)
C
947.37
150(2)
0.71073
47H34Cl2FeMoO4P2
C46H32FeMoO4P2
862.45
158(2)
˚
Wavelength (A)
0.71073
0.71073
Crystal system
Space group
Orthorhombic
Pca21
20.316(8)
12.054(5)
25.007(10)
90
90
90
6124(4)
8
Monoclinic
P21/c
18.1287(11)
12.4033(7)
19.0262(10)
90
108.3750(10)
90
4060.0(4)
4
Monoclinic
C2/c
18.103(5)
11.230(3)
19.901(6)
90
99.468(9)
90
3990.7(19)
4
˚
a (A)
˚
b (A)
˚
c (A)
h (°)
i (°)
k (°)
3
˚
Volume (A )
Z
Calculated density (Mg/m3)
Absorption coefficient (mm−1
F(000)
1.486
2.628
2744
1.550
0.922
1920
1.435
0.801
1752
)
Crystal size (mm)
q range for data collection (°)
Limiting indices
0.4×0.35×0.15
2.75 to 26.53
−255h514
−145k512
−275l530
22827/11336 [Rint\0.0398]
94.6%
SADABS
11336/1/694
0.950
0.5×0.3×0.2
3.17 to 23.28
−195h519
−135k512
−75l521
9239/5404 [Rint\0.0306]
92.4%
SADABS
5404/0/509
1.092
0.7×0.5×0.3
2.82 to 26.29
−225h520
−135k513
−245l524
22105/3920 [Rint\0.0210]
96.7%
SADABS
3920/0/245
1.076
Reflections collected/unique
Completeness to qmax
Absorption correction
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [I\2|(I)]
R1
0.0371
0.0675
0.0558
0.1504
0.0237
0.0574
wR2
R indices (all data)
R1
wR2
Largest diff. peak (e A
Largest diff. hole (e A
0.0641
0.0742
0.664
0.0652
0.1605
2.595
0.0291
0.0612
0.431
−3
˚
˚
)
−3
)
−0.414
−1.147
−0.372
from 4 via diphenylphosphinoindenide were revealed,
by X-ray crystallography, to be the meso isomer 5a,
whereas crystals of 5 obtained when 4 was prepared via
the tetraphosphine 3 were revealed, also by X-ray crys-
tallography, to be the racemic isomer 5b. Spectra ob-
tained using individual crystals of 5a and 5b shows
them to be almost indistinguishable spectroscopically.
The isolation of a single crystal of one particular isomer
of complex 5 does not preclude the presence of both
isomers in the mixture and hence it is impossible to
ascertain, from the data, whether both isomers are
present in 4. Therefore, we are also unable to determine
whether the preparative route is relevant. Like 4, both
isomers of 5 have symmetrically identical indenyl lig-
ands and a single resonance in the 31P-NMR spectrum
at 33.1 ppm is observed that is similar to that of the
dppf analogue Mo(CO)4(dppf) (33.9 ppm) [15].
intensity band at 2021 cm−1, essentially unchanged
from that found for Mo(CO)4(dppf). The other bands,
however, are at lower energy and have different relative
intensities from those found for Mo(CO)4(dppf). For
the C2-symmetric isomer 5b, the band at 1913 cm−1 is
now the strongest band and the lowest energy band at
1878 cm−1 has approximately half the intensity of the
1913 cm−1 band. The infra-red spectrum of the meso
isomer 5a is almost identical to 5b but has a slight
splitting of the strongest band (to 1916 and 1909
cm−1).
The X-ray structural analysis of 5a shows one inde-
pendent molecule in the asymmetric unit. Bond dis-
tances are given in Table 1, selected bond angles in
Table 2, crystal data and structure refinement parame-
ters in Table 3, and the atomic coordinates and equiva-
lent isotropic displacement parameters are given in
Table 5. Fig. 2 shows a thermal ellipsoid plot with the
adopted numbering scheme. Each indenyl-phosphine
ligand is coordinated to an iron atom in an h5 coordi-
nation mode via the indenyl five-membered ring, and
The infrared spectrum of Mo(CO)4(dppf) shows a
medium intensity band at 2020 cm−1, a strong band at
1921 cm−1, and a very strong band at 1901 cm−1 [15].
Both 5a and 5b show the same high-frequency medium-

J.J. Adams et al. / Journal of Organometallic Chemistry 580 (1999) 245–256
249
Table 4
Table 4 (Continued)
Atomic coordinates (×104) and equivalent isotropic displacement
2
3
a
˚
parameters (A ×10 ) for 2
x
y
z
Ueq
x
y
z
Ueq
C(26%)
C(31%)
C(32%)
C(33%)
C(34%)
C(35%)
C(36%)
C(41%)
C(42%)
C(43%)
C(44%)
C(45%)
C(46%)
C(10)
Cl(1)
5333(3)
8107(2)
7866(2)
7756(3)
7885(2)
8108(2)
8235(2)
8232(2)
7606(3)
7545(3)
8110(3)
8724(3)
8789(2)
4772(3)
4496(1)
5556(1)
−6678(4)
8012(2)
6380(2)
6351(2)
5858(2)
5394(2)
5414(2)
5905(2)
7523(2)
7704(2)
8054(2)
8223(2)
8054(2)
7703(2)
8406(3)
8982(1)
8212(1)
42(1)
25(1)
36(1)
39(1)
35(1)
34(1)
30(1)
28(1)
41(1)
48(2)
48(2)
40(1)
34(1)
63(2)
94(1)
59(1)
−10014(4)
−11097(4)
−11589(4)
−11011(4)
−9928(4)
−9438(4)
−10406(4)
−10730(4)
−11616(4)
−12183(4)
−11859(4)
−10964(4)
8678(5)
Se(1)
Se(2)
P(1)
P(2)
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
C(9)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(21)
C(22)
C(23)
C(24)
C(25)
C(26)
C(31)
C(32)
C(33)
C(34)
C(35)
C(36)
C(41)
C(42)
C(43)
C(44)
C(45)
C(46)
Se(1%)
Se(2%)
P(1%)
5702(1)
2286(1)
5661(1)
3224(1)
4810(2)
4394(2)
3884(2)
3905(2)
3496(2)
3615(3)
4132(3)
4558(3)
4447(2)
6015(2)
5920(2)
6242(3)
6668(3)
6759(2)
6431(2)
6082(2)
6149(2)
6459(2)
6711(3)
6639(3)
6330(2)
3423(2)
3661(2)
3779(3)
3667(2)
3447(2)
3324(2)
3296(2)
3901(2)
3947(3)
3396(3)
2792(3)
2737(2)
5832(1)
9235(1)
5868(1)
8304(1)
6724(2)
7149(2)
7641(2)
7594(2)
7978(3)
7847(3)
7340(3)
6941(2)
7063(2)
5510(2)
5636(2)
5319(3)
4860(2)
4734(2)
5051(2)
5472(2)
5357(2)
5108(3)
4971(3)
5074(3)
−3871(1)
−3398(1)
−2532(1)
−4175(1)
−2046(3)
−2977(3)
−3212(3)
−2461(4)
−2380(4)
−1554(5)
−813(5)
4762(1)
5487(1)
5306(1)
5475(1)
5449(2)
5674(2)
5344(2)
4875(2)
4432(2)
4058(2)
4132(2)
4573(2)
4938(2)
5959(2)
6411(2)
6885(2)
6923(2)
6485(2)
6007(2)
5071(2)
5403(2)
5207(2)
4691(3)
4362(2)
4548(2)
6104(2)
6132(2)
6623(2)
7090(2)
7068(2)
6575(2)
4956(2)
4716(2)
4337(2)
4203(2)
4433(2)
4806(2)
7532(1)
6996(1)
7119(1)
7012(1)
7018(2)
6793(2)
7144(2)
7616(2)
8080(2)
8449(2)
8359(2)
7909(2)
7539(2)
6450(2)
6053(2)
5563(2)
5465(2)
5847(2)
6340(2)
7479(2)
7230(2)
7521(3)
8064(3)
8307(3)
38(1)
34(1)
28(1)
26(1)
28(1)
26(1)
25(1)
26(1)
32(1)
43(1)
47(2)
38(1)
27(1)
28(1)
34(1)
47(2)
47(2)
41(1)
34(1)
29(1)
36(1)
42(1)
45(1)
45(1)
35(1)
26(1)
32(1)
38(1)
38(1)
37(1)
32(1)
29(1)
39(1)
45(2)
46(2)
42(1)
34(1)
36(1)
34(1)
28(1)
27(1)
26(1)
26(1)
26(1)
29(1)
41(1)
45(2)
43(1)
35(1)
29(1)
28(1)
34(1)
45(1)
45(1)
38(1)
33(1)
32(1)
41(1)
53(2)
61(2)
58(2)
−895(4)
−1734(4)
−2849(4)
−2184(4)
−2396(5)
−3300(5)
−3979(4)
−3775(4)
−1295(4)
−351(4)
8009(2)
8191(1)
Cl(2)
the phosphorus atom is coordinated to a molybdenum
atom. The indenyl rings are twisted by 35.6° (C3–
CNT–CNT%–C3%; CNT=centroid of the five-mem-
bered ring) with respect to each other to give a synclinal
(or gauche) conformation. The molybdenum atom has
the two phosphorus atoms bound in a cis fashion to
give an octahedral geometry with the other four coordi-
nation sites occupied by carbonyl ligands. In order to
accommodate the large molybdenum atom, either a
half-chair (6a and 6b) or twist-boat (6c) conformation
must be adopted (Fig. 3). Half-chair conformations are
rare in chelated dppf complexes and it can be seen that
for 6a there is an unfavourable phenyl-phenyl interac-
tion. The other half-chair conformation, 6b, has two
unfavourable phenyl-benzo interactions as well as a
phenyl-phenyl interaction. The twist-boat conforma-
tion, 6c, is the preferred conformation; there are no
phenyl-phenyl interactions and there is only one
phenyl–benzo interaction. It should be noted that this
conformation removes the Cs symmetry of the molecule
that is found in the NMR spectra. The phenyl-benzo
interaction has a dramatic effect on the diphenylphos-
phine group: the phenyl ring is forced perpendicular to
the benzo ring which brings H15¦ within the van der
Waals radii of C5, H5, and C16* (2.68, 2.30 and 2.76
595(4)
618(4)
−282(5)
−1242(4)
−4843(4)
−5937(4)
−6430(4)
−5835(4)
−4755(4)
−4262(4)
−5219(4)
−5450(4)
−6287(4)
−6908(4)
−6672(4)
−5825(4)
−9233(1)
−8536(1)
−7704(1)
−9339(1)
−7195(3)
−8129(4)
−8382(3)
−7652(4)
−7583(4)
−6757(5)
−6008(4)
−6069(4)
−6910(4)
−7766(4)
−6969(4)
−7023(4)
−7870(5)
−8652(4)
−8609(4)
−6559(4)
−5539(4)
−4650(4)
−4787(5)
−5787(5)
P(2%)
C(1%)
C(2%)
C(3%)
C(4%)
C(5%)
C(6%)
C(7%)
C(8%)
C(9%)
C(11%)
C(12%)
C(13%)
C(14%)
C(15%)
C(16%)
C(21%)
C(22%)
C(23%)
C(24%)
C(25%)
˚
˚
A, respectively). Consequently, P% deviates 0.230 A
from its C5 ring, away from the iron atom, compared to
˚
0.005 A for P (towards the iron atom) and 0.017/0.026
˚
A for Mo(CO)4(dppf) [16]. The average deviation for
˚
chelated dppf complexes is 0.05 A towards the Fe atom
and the largest deviation reported in the review by Gan
and Hor [2] is 0.157 A, away from the iron atom, for
the eclipsed synperiplanar complex NiBr2(dppf) [16].
The CNT%–C3%–P% angle of 169.2° is smaller than the
CNT–C3–P angle of 176.1°. The P–Mo–P% bite angle
˚

250
J.J. Adams et al. / Journal of Organometallic Chemistry 580 (1999) 245–256
of 98.71° is slightly larger than the dppf analogue
15 Hz), and l(Cb) 73.1 (3JPC=3.5 Hz) [17]. For (h5-
C9H7)2Fe, the unique carbon atom, C-2, is 8.0 ppm
downfield of C-1/C-3 (70.3 ppm versus 62.3 ppm, re-
spectively) and the quaternary carbon atoms, C-4/C-9,
are a further 17.3 ppm downfield at 87.6 ppm [18].
Based on the above trends, the 13C spectrum of 4 is
assigned as follows: the resonance at l 91.0, with a
large P–C coupling constant (25 Hz), is assigned to C-4
(95.3(1)°) and the Mo–P distances (Mo–P=2.5577(14)
˚
˚
A and Mo–P%=2.5691(15) A) are similar to each other
˚
as well as the dppf analogue (2.560(16) A). Other
conformational measures are typical of chelated dppf
complexes
(the
corresponding
values
for
Mo(CO)4(dppf) are given in parentheses [16]): the tor-
sional twist (C3–CNT–CNT%–C3%)=35.6° (41.9°),
CNT–Fe–CNT%=176.5° (179.0°), q (the angle between
3
and the resonance at l 89.7 (with a smaller JPC of 4
˚
˚
the C5 planes)=5.9° (2.2°), P…P=3.881 A (3.783 A).
The X-ray structural analysis of 5b revealed one
independent half-molecule with the other half being
related by a C2 axis through the Fe and Mo atoms.
Bond distances are given in Table 1, selected bond
angles in Table 2, crystal data and structure refinement
parameters in Table 3, and the atomic coordinates and
equivalent isotropic displacement parameters are given
in Table 6. Fig. 4 shows a thermal ellipsoid plot with
the adopted numbering scheme. As with 5a, either a
half-chair (7a) or twist-boat conformation (7b and 7c)
must be adopted to accommodate the molybdenum
atom. The half-chair conformation has one benzo-
phenyl interaction as well as a phenyl-phenyl interac-
tion. Of the two twist-boat conformations, 7b has two
phenyl-benzo interactions whereas 7c has neither
phenyl-benzo nor phenyl-phenyl interactions. Conse-
quently, the adopted conformation 7c is the least steri-
cally-strained conformation. Notably, this con-
formation also retains the C2 symmetry that is observed
in the NMR spectra. Unlike 5a, the P atom does not
Hz) to the other quaternary carbon, C-9. Atom C-3,
1
which appears further upfield at l 68.1 with JPC=9
Hz, is distinguishable by its lower intensity compared to
the C-1 and C-2 resonances. C-2 appears 5.9 ppm
downfield of C-1, l 72.0 versus l 66.1, respectively. C-2
2
has a much smaller JPC (4 Hz) than C-4 (25 Hz) which
indicates that the phosphorus lone pair is oriented
towards C-4 [19] thereby minimising steric interactions
3
between H-5 and the phenyl ring. JPC for C-1 is the
same as that of C-9.
The phenyl rings on each phosphorus atom are in-
equivalent, so two sets of phenyl resonances are ob-
served. As is typical of phenyl-phosphine compounds,
1
2JPC (22 and 18 Hz) is greater than JPC (10 and 7 Hz)
and 3JPC (8 and 5 Hz). Of the benzo carbon atoms, only
3
C-5 shows PC coupling: JPC=9 Hz.
Coordination of 4 to a Mo(CO)4 fragment reduces
significantly the P-C coupling constants and causes
downfield shifts for C-3 (8.3 ppm to l 76.4) and C-2
(7.9 ppm to l 79.9), whereas C-4 and C-9 exhibit small
upfield shifts (1.3 ppm and 2.6 ppm, respectively). C-1
is relatively unchanged.
˚
deviate significantly from its C5 ring (0.048 A away
from the iron atom) and the CNT–C3–P angle of
175.8° is normal. The P–Mo–P% bite angle of 99.44(3)°
is slightly larger than in 5a (98.71°) and the dppf
analogue (95.3(1)°) and the torsional twist (C3–CNT–
CNT%–C3%=25.8°) is significantly less than in both 5a
(35.6°) and Mo(CO)4(dppf) (41.9°). The other confor-
mational measures are typical of chelated dppf com-
The assignments of the C-1 and C-2 resonances of 1,
are readily made based on their chemical shifts, intensi-
ties, and coupling constants: C-1 is significantly upfield
at l 49.5 and appears as a doublet of doublets, the
1
larger coupling constant of 23 Hz is JPC and the
3
smaller coupling constant of 4 Hz is JPC. These cou-
pling constants are both smaller than the corresponding
values for 1-Ph2P(C9H7) (34 Hz) and 3-Ph2P(C9H7) (6
Hz) [9]. C-2 at l 142.4 has greater intensity than the
slightly upfield resonance of C-3 at l 141.6. The larger
of the two-bond coupling constants for C-2 (7 Hz) is
assigned to coupling with the P atom on C-1 and the
smaller (3 Hz) with the P atom on C-3: C-4 shows a
˚
plexes: Mo–P=2.5658(7) A; CNT–Fe–CNT%=
˚
174.8°; q=5.7°; and P…P=3.914 A.
2.4. 13C-NMR spectroscopy
Table 7 summarises the 13C chemical shifts and P–C
coupling constants for the carbon atoms in the five-
membered ring of the indene and indenyl compounds.
The labelling scheme is shown in Fig. 5: we have
labelled 4 and 5 with the phosphorus-bound carbon
atoms as C-3 for ease of comparison.
2
large JPC (18 Hz) indicating that the lone pair of the P
atom on C-3 is oriented towards C-4, this would then
2
3
give the observed small JPC for C-2. JPC for C-4 is
very small at 2 Hz, but this is similar to that of
1-Ph2P(C9H7) at 1.5 Hz. The one-bond coupling con-
stant of 14 Hz for C-3 is typical of an sp2 carbon atom;
3JPC is somewhat smaller at 5 Hz. C-9 has a moderate
2JPC of 8 Hz (cf. 9 Hz for 1-Ph2P(C9H7)) and a typical
3JPC of 4 Hz (cf. 5 Hz for 3-Ph2P(C9H7)). The chemical
shifts of C-4 and C-9 are both downfield of the other
indene resonances at l 145.3 and l 144.9, respectively.
Our assignment for 3-Ph2P(C9H7) differs from that of
Houlton and co-workers found that functionalisation
of Cp with PPh2 causes a downfield shift for all ring-
carbon resonances and that, as with phenyl-phosphines,
1
3
2JPC is greater than JPC and JPC for FeCp(C5H4PPh2),
l(Cp) 69.0, l(CP) 76.6 (1JPC=0 Hz), l(Ch) 72.8
(2JPC=14.7 Hz), and l(Ci) 70.6 (3JPC=3.4 Hz); and
for dppf, l(CP) 77.6 (1JPC=4 Hz), l(Ch) 74.6 (2JPC
=

J.J. Adams et al. / Journal of Organometallic Chemistry 580 (1999) 245–256
251
Fig. 1. Thermal ellipsoid plot of one molecule of 2.
Anderson and co-workers who assigned the downfield
resonance at l 145.9, with the large coupling constant
of 20 Hz, to C-3 and the upfield resonance at l 141.9,
with a moderate coupling constant of 13 Hz, to C-4.
Since 1 has a stereocentre at C-1, the four phenyl
rings are inequivalent and four sets of resonances are
observed. The meta, para and ortho carbons have simi-
lar chemical shifts and coupling constants: l 128.0–
128.4 (3JPC=6–9 Hz, m-Ph), 128.6–129.2 (p-Ph),
133.3–133.9 (2JPC=19–21 Hz, o-Ph). The ipso carbons
have similar chemical shifts but exhibit two sizes of
1JPC: The smaller coupling constants are attributed to
the phenyl rings on the phosphorus atom attached to
the sp3 carbon atom C-1 (l 135.3 (1JPC=8 Hz), 135.3
(1JPC=8 Hz)); and the larger coupling constants are
attributed to the phenyl rings on the phosphorus atom
attached to the sp2 carbon atom C-3 (l 135.8 (1JPC=18
Hz), 136.2 (1JPC=19 Hz)). Given our ability to distin-
guish the four inequivalent phenyl rings in 1, it seems
peculiar that the rac and meso isomers of 4 and 5 are so
similar.
Coordination of the phosphorus atoms of 1 to sele-
nium to give compound 2 causes downfield shifts for
both C-1 (l 49.5 to l 55.3) and C-2 (l 142.4 to l 143.5)
as well as an increase in the coupling constants (see
Table 7).
3. Conclusions
We have isolated and characterised the diphosphino-
indene compound 1,3-(Ph2P)2C9H6 (1). The ferrocene
complex of the corresponding indenide is unstable to
formation of the bis(phosphinoindenyl)iron complex 4.
This complex exists in two isomeric forms: a racemic
form with C2 symmetry and a meso form with Cs
symmetry. The racemic isomer, in particular, has sig-
nificant potential in the area of asymmetric synthesis
and catalysis as a C2 analogue of dppf. We have
reported initial investigations into its coordination
chemistry: Coordination of 4 to a Mo(CO)4 fragment
gives a heterobimetallic Fe–Mo complex with racemic
and meso isomers. Whereas the racemic isomer exhibits
only C2 symmetry, the meso isomer exhibits C1 symme-
try in the solid state and solution infra-red spectrum
but Cs symmetry in the NMR solution spectra. Efforts
to understand the formation of 4 from the tetraphos-
phine 3, to determine the racemic:meso ratio of 4 and
to separate these isomers are continuing.
4. Experimental
4.1. General considerations
Scheme 2.
All manipulations and reactions were carried out

252
J.J. Adams et al. / Journal of Organometallic Chemistry 580 (1999) 245–256
Table 5
under an inert atmosphere by use of standard Schlenk
line techniques. Reagent grade solvents were dried and
distilled prior to use: diethyl ether, toluene and tetrahy-
drofuran from Na/benzophenone; dichloromethane,
heptane and pentane from CaH2; ethanol from magne-
sium. Indene was distilled prior to use and cyclohexane
and ethylacetate were saturated with dinitrogen prior to
use. Mo(CO)4(piperidine)2 was prepared as described in
the literature [20]. All other reagents were used as
Atomic coordinates (×104) and equivalent isotropic displacement
2
3
a
˚
parameters (A ×10 ) for 5a
Atom
x
y
z
Ueq
26(1)
Mo
Fe
P
P´ı
C(1)
C(1%)
C(2)
C(2%)
C(3)
C(3%)
C(4)
C(4%)
C(5)
C(5%)
C(6%)
C(6)
3167(1)
8415(1)
6967(1)
9222(1)
6527(1)
7749(4)
5628(4)
8221(4)
6107(4)
8562(4)
6125(4)
8374(4)
5610(4)
8581(4)
5399(4)
4943(4)
8227(5)
7668(5)
4675(5)
4842(4)
7490(5)
5305(4)
7850(4)
5375(5)
6217(4)
9503(4)
3920(1)
1650(1)
2616(1)
3593(1)
646(3)
1912(1)
2760(1)
2576(1)
1568(3)
2509(4)
2252(3)
2845(3)
2110(3)
2279(3)
1288(3)
1582(3)
803(3)
26(1)
25(1)
25(1)
30(1)
33(1)
29(1)
30(1)
28(1)
26(1)
26(1)
27(1)
28(1)
30(1)
30(1)
35(1)
37(1)
35(1)
33(1)
35(1)
29(1)
29(1)
27(1)
26(1)
29(1)
28(1)
49(2)
36(1)
39(2)
37(1)
41(2)
63(2)
42(2)
45(2)
46(2)
45(2)
49(2)
40(2)
39(2)
37(1)
39(2)
43(2)
33(1)
33(1)
35(1)
35(1)
35(1)
34(1)
41(2)
33(1)
113(4)
50(1)
46(1)
51(1)
65(2)
110(1)
113(1)
1
supplied by Aldrich Chemical Company. H-, 13C{1H}-
1523(3)
1129(3)
2238(3)
1796(3)
2625(3)
1684(3)
2140(3)
2128(3)
2198(3)
1613(3)
1889(3)
1209(3)
955(3)
and 31P{1H}-NMR data were collected on a Varian
XL-300 spectrometer operating at 300, 75 and 121
MHz, respectively, except for the 1H-NMR spectrum of
2 which was collected on a Varian Unity 300 using an
inverse-detection probe. Unless otherwise stated, spec-
tra were measured at ambient temperature with residue
solvent peaks as internal standard for 1H- and 13C{1H}-
NMR. 31P{1H}-NMR chemical shifts are reported rela-
tive to external 85% H3PO4, positive shifts representing
deshielding. EI and FAB mass spectra were collected
on a Kratos MS80RFA mass spectrometer. IR spectra
were obtained on a Shimadzu FTIR-8201PC spec-
trophotometer. Elemental analyses were done by
Campbell Microanalysis Services, Otago University,
Dunedin.
829(3)
271(3)
55(4)
−247(4)
420(4)
C(7)
C(7%)
C(8%)
C(8)
C(9%)
C(9)
1129(4)
178(3)
872(3)
754(3)
1734(3)
966(3)
1462(3)
980(3)
C(10%)
C(10¦)
C(10)
C(10*)
C(11%)
C(11*)
C(11)
C(11¦)
C(12*)
C(12%)
C(12¦)
C(12)
C(13¦)
C(13)
C(13%)
C(13*)
C(14%)
C(14)
C(14*)
C(14¦)
C(15¦)
C(15)
C(15*)
C(15%)
C(16)
C(16*)
C(16¦)
C(16%)
C(17)
O(16)
O(16*)
O(16%)
O(16¦)
Cl(1)
Cl(2)
3218(3)
1726(3)
3634(3)
2302(3)
3698(4)
2000(3)
3970(4)
1668(4)
1673(4)
4179(5)
997(4)
3984(3)
3888(3)
2353(3)
2488(3)
4713(4)
1776(4)
2463(3)
4291(3)
1658(4)
5024(4)
4459(4)
2323(4)
4232(4)
2059(4)
4599(4)
2253(3)
3901(4)
1955(3)
2952(4)
3840(4)
3683(3)
2109(3)
3080(3)
3595(3)
4999(4)
4142(3)
4213(4)
3777(3)
836(6)
10562(4)
5398(5)
10986(5)
10526(5)
5294(5)
12001(5)
4518(6)
5089(5)
10720(5)
5774(6)
9900(6)
3594(5)
12620(5)
3550(5)
8887(5)
12205(5)
6693(6)
6925(5)
8690(5)
11177(5)
4430(5)
8074(5)
9018(5)
9808(5)
7764(5)
12570(12)
7987(4)
9372(4)
7384(4)
10582(4)
12858(3)
13310(2)
4.2. Preparation, isolation and characterisation of
1,3-bis(diphenylphosphino)indene (1)
To a solution of indene (1.16 g, 1 mmol) in di-
ethylether was added n-BuLi (6.25 ml, 1.6 M, 1 mmol)
at −80°C. After stirring the reaction mixture for 30
min at ambient temperature and followed by cooling to
−80°C, ClPPh2 (2.2 g, 1 mmol) was added. After 1 h
stirring at ambient temperature, the solution was again
cooled to −80°C and n-BuLi (6.25 ml, 1.6 M, 1 mmol)
was added. The solution was then stirred for 30 min
before the addition of a second equivalent of ClPPh2
(2.2 g, 1 mmol) at −80°C. After 1 h of stirring at
ambient temperature, the reaction mixture was filtered
through alumina, the solvent evaporated and the
residue washed with ethanol to give 4.2 g (87% yield) of
4668(4)
371(4)
5022(4)
4151(4)
1633(4)
3670(4)
4707(4)
1909(4)
417(4)
1100(3)
4021(3)
2250(4)
3203(3)
3569(4)
2221(4)
3739(4)
4144(4)
3289(7)
3809(3)
1717(3)
4706(3)
4089(3)
2458(2)
3498(2)
1
1 as a white powder. H-NMR (CDCl3): l 4.46 (s, 1H,
H-1), 6.04 (s, 1H, H-2), 6.9–7.4 (m, 24H, H-5–H-8 and
4
Ph). 31P{1H}-NMR (CDCl3): l −21.6 (d, JPP=4 Hz,
PC-3), −1.1 (d, 4JPP=4 Hz, PC-1). 13C{1H}-NMR
3
1
(CDCl3): l 49.5 (dd, JPC=4 Hz, JPC=23 Hz, C-1),
5630(3)
4312(3)
3738(3)
4415(3)
122(1)
3
3
121.7 (d, JPC=5 Hz, C-5), 123.8 (d, JPC=5 Hz, C-8),
124.9 (s, C-6), 126.5 (s, C-7), 128.0 (d, 3JPC=6 Hz,
m-Ph), 128.36 (d, 3JPC=7 Hz, m-Ph), 128.37 (d,
3JPC=9 Hz, m-Ph), 128.4 (d, 3JPC=7 Hz, m-Ph), 128.6
(s, p-Ph), 128.7 (s, p-Ph), 128.9 (s, p-Ph), 129.2 (s,
p-Ph), 133.3 (d, 2JPC=19 Hz, o-Ph), 133.7 (d, 2JPC=20
Hz, o-Ph), 133.7 (d, 2JPC=20 Hz, o-Ph), 133.9 (d,
1607(2)
a Ueq is defined as one third of the trace of the orthogonalized Uij
tensor.
1
2JPC=21 Hz, o-Ph), 135.3 (d, JPC=8 Hz, ipso-Ph),

J.J. Adams et al. / Journal of Organometallic Chemistry 580 (1999) 245–256
253
Table 6
Atomic coordinates (×104) and equivalent isotropic displacement
2
3
a
˚
parameters (A ×10 ) for 5b
Atom
x
y
z
Ueq
Mo
Fe
P
5000
5000
8512(1)
2500
2500
25(1)
28(1)
24(1)
41(1)
33(1)
27(1)
29(1)
35(1)
46(1)
53(1)
50(1)
38(1)
27(1)
33(1)
41(1)
48(1)
57(1)
45(1)
33(1)
41(1)
53(1)
58(1)
57(1)
45(1)
37(1)
41(1)
61(1)
67(1)
12594(1)
9989(1)
13661(2)
12567(2)
11584(2)
12108(2)
11605(2)
12349(2)
13607(2)
14126(2)
13392(2)
9900(2)
10416(2)
10288(2)
9603(2)
9043(3)
9210(2)
9719(2)
8664(2)
8470(3)
9322(3)
10379(3)
10576(2)
8403(2)
7250(2)
8233(2)
6498(1)
6091(1)
5934(1)
6063(1)
5970(1)
5823(1)
5750(1)
5621(1)
5546(1)
5630(1)
5793(1)
6487(1)
6102(1)
6357(1)
6985(1)
7356(1)
7118(1)
6926(1)
7013(1)
7662(1)
8213(1)
8132(1)
7491(1)
5132(1)
4230(1)
5211(1)
3796(1)
2567(1)
2569(1)
2244(1)
2691(1)
3328(1)
3977(1)
4492(1)
4391(1)
3794(1)
3242(1)
1771(1)
1171(1)
553(1)
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
C(9)
C(10)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(17)
C(18)
C(19)
C(20)
C(21)
C(22)
C(23)
O(1)
O(2)
515(1)
1098(1)
1727(1)
3230(1)
3608(1)
4094(1)
4204(1)
3840(1)
3350(1)
3541(1)
2496(1)
4120(1)
2512(1)
Fig. 2. Thermal ellipsoid plot of 5a.
135.8 (d, 1JPC=18 Hz, ipso-Ph), 136.2 (d, 1JPC=19 Hz,
2
3
ipso-Ph), 141.6 (dd, JPC=5 Hz, JPC=14 Hz, C-3),
a Ueq is defined as one third of the trace of the orthogonalized Uij
tensor.
2
2
142.4 (dd, JPC=3 Hz, JPC=7 Hz, C-2), 144.9 (dd,
2JPC=4 Hz, 3JPC=8 Hz, C-9), 145.3 (dd, 1JPC=18 Hz,
3JPC=2 Hz, C-4). Mass spectra (EI, m/z (%)): 484 (29,
M+), 299 (100, M+-PPh2), 185 (24, PPh2+), 108 (20,
PPh+). Anal. Calc. for C33H26P2: C, 81.8; H, 5.41.
Found: C, 80.4; H, 5.58. The carbon analysis may be
low due to oxide formation.
4.3. Preparation of 1,3-bis(diphenylselenophos-
phino)indene (2)
Compound 1 (0.89 g, 1.8 mmol) and selenium (0.291
g, 3.7 mmol) were stirred in toluene (25 ml) for 12 h
Fig. 3. The possible half-chair and twist-boat conformations of 5a and 5b.

254
J.J. Adams et al. / Journal of Organometallic Chemistry 580 (1999) 245–256
Fig. 5. The adopted atom labelling scheme for the phosphino-indene
and -indenyl compounds.
3
7.14 (dd, JHH=8 Hz, 1H, H-6), 7.32 (m, 1H, H-8),
7.8–7.3 (m, 20H, Ph). 31P{1H}-NMR (CDCl3): l 37.9 (m,
1
4
4JPP 6 Hz, JSeP 750 Hz, PC-1), 20.9 (m, JPP=6 Hz,
1JSeP=730 Hz, PC-3). 13C{1H}-NMR (CDCl3): l 55.3
(dd, 3JPC=12 Hz, 1JPC=38 Hz, C-1), 123.8 (C-8), 124.5
(C-5), 126.2 (s, C-7), 128.0 (s, C-6), 128–129 (Ph),
131–133 (Ph), 143.5 (dd, 2JPC=11 Hz, 2JPC=4 Hz, C-2).
Mass spectra (EI, m/z (%)): 644 (5, M+), 564 (5, M+-Se),
484 (1, M+-2Se), 380 (20, SePPh2C9H7+), 299 (50,
PPh2C9H6+), 185 (100, PPh2+), 108 (80, PPh+). Anal.
Calc. for C33H26P2Se2 · 0.5CH2Cl2: C, 58.75; H, 3.97.
Found: C, 58.91; H, 3.98.
4.4. Preparation of bis(1-diphenylphosphinoin-
denyl)iron(II) (4) from 1 6ia bis(1,3-bis(diphenylphos-
phino)indenyl)iron(II) (3)
Fig. 4. Thermal ellipsoid plot of 5b.
To a solution of 1 (9.6 g, 2 mmol) in tetrahydrofuran
(100 ml) at −80°C was added a solution of n-BuLi (12.5
ml, 1.6 M, 2 mmol). After allowing to warm to ambient
temperature over one hour, FeCl2 (1.26 g, 1 mmol) was
added and the reaction mixture stirred for a further 2 h.
31P-NMR spectroscopy of the solution showed a single
peak at l −19.9 which is attributed to 3. The solvent
was then removed in vacuo. The residue shows a complex
31P-NMR spectrum. Chromatography on silica gel with
a 5:1 mixture of cyclohexane and ethylacetate gave dark
at ambient temperature and then heated to reflux for 2
h. 31P-NMR spectroscopy indicated 100% conver-
sion. Colourless crystallographic-quality crystals (0.527
g, 45% yield), containing one half-equivalent of CH2Cl2
solvate, were obtained by recrystallisation from CH2Cl2/
pentane. H-NMR (CDCl3): l 5.13 (ddd, JPH=22 Hz,
3JHH=2 Hz, 4JPH=2 Hz, 1H, H-1), 6.40 (ddd, 3JPH=10
Hz, 3JPH=4 Hz, 3JHH=2 Hz, 1H, H-2), 6.87 (d,
3JHH=7 Hz, 1H, H-5), 7.03 (dd, 3JHH=8 Hz, 1H, H-7),
1
1
Table 7
13C-NMR chemical shifts (ppm) for the indenyl five-membered-ring carbon atomsa
Compound
C-1
C-2
C-3
C-4
C-9
1-Ph2P(C9H7)b
48.6 (34)
40.2 (6)
40.2 (6)
49.5 (23,4)
55.0
132.1 (5)
142.0 (5.5)
142.0 (5.5)
142.4 (7,3)
144.6
135.0 (4)
145.9 (20)
141.9 (13)
141.6 (14,5)
–
–
144.6 (1.5)
141.9 (13)
145.9 (20)
145.3 (18,2)
–
–
144.0 (9)
144.8 (5)
144.8 (5)
144.9 (8,4)
–
3-Ph2P(C9H7)b,c
3-Ph2P(C9H7)d
1,3-(Ph2P)2C9H6 (1)
1,3-(Ph2PO)2C9H6
1,3-(Ph2PS)2C9H6
e
e
56.3
143.5
–
1,3-(Ph2PSe)2C9H6 (2)
4
55.3 (38,12)
66.1 (4)
66.8
143.5 (11,4)
72.0 (4)
79.9 (5)
70.3
–
–
–
68.1 (9)
76.4
62.3
91.0 (25)
89.7
87.6
89.7 (4)
87.1
87.6
5
(C9H7)2Fef
62.3
a PC coupling constants (Hz) are given in parentheses.
b Fallis et al. [9].
c In CH2Cl2, all others are in CDCl3.
d Our assignment.
e Stradiotto et al. [11].
f Benn et al. [18].

J.J. Adams et al. / Journal of Organometallic Chemistry 580 (1999) 245–256
255
green 4 which was recrystallised from toluene to give 2.2
g (20% yield) of product. H-NMR (CDCl3): l 3.07 (s,
836 (3, M+ –CO), 808 (5, M+ –2CO), 780 (2, M+
–
3CO), 752 (15, M+ –4CO), 396 (25, [MoPPh2C9H5]+),
307 (55), 154 (90), 136 (100). Infra-red (CHCl3): 5a; 2021
(m), 1916 (sh, br), 1909 (s, br), 1878 (m, br) cm−1. 5b;
1
2H, H-1), 4.92 (s, 2H, H-2), 6.4–7.4 (m, 28H, H-5–H-8
and Ph). 13C{1H}-NMR (CDCl3): l 66.1 (d, 2JPC=4 Hz,
1
3
C-1), 68.1 (d, JPC=9 Hz, C-3), 72.0 (d, JPC=4 Hz,
2021 (m), 1913 (s, br), 1878 (m, br) cm−1
.
2
3
C-2), 89.7 (d, JPC=4 Hz, C-9), 91.0 (d, JPC=25 Hz,
C-4), 122.5 (s, C-7), 122.9 (s, C-6), 123.6 (s, C-8), 124.1
4.7. Crystal structure determinations
3
3
(d, JPC=9 Hz, C-5), 127.6 (s, p-Ph), 128.0 (d, JPC=5
Hz, m-Ph), 128.3 (d, 3JPC=8 Hz, m-Ph), 129.3 (s, p-Ph),
X-ray crystallographic data for 2, 5a and 5b were
collected from single-crystal samples, which were
mounted on a glass fibre. Data was collected at ca. 150
K using a Siemens P4 diffractometer equipped with a
Siemens SMART 1K charge-coupled device (CCD) area
detector (using the program SMART [21]) and graphite
2
2
131.7 (d, JPC=18 Hz, o-Ph), 135.2 (d, JPC=22 Hz,
o-Ph), 136.7 (d, 1JPC=7 Hz, ipso-Ph), 139.8 (d, 1JPC=10
Hz, ipso-Ph). 31P{1H}-NMR (CDCl3): l −22.5 (s).
Anal. Calc. for C42H22FeP2: C, 77.2; H, 5.59. Found: C,
75.2; H, 5.21. C and H low due to oxide formation. Mass
spectra: (EI, m/z (%)): 654 (42, M+), 300 (81, HIP+),
185 (100, P–Ph2+). High resolution: M+ Calc.,
654.13283; Found, 654.13318.
˚
monochromated Mo–Ka radiation (u\0.71073 A). The
crystal to detector distance was 6.0 cm and the data
collection was carried out in 512×512 pixel mode
utilising 2×2 pixel binning. The initial unit cell parame-
ters were determined by least-squares fit of the angular
settings of strong reflections in 100 frames over three
different parts of reciprocal space (300 frames in total).
One complete hemisphere of data was collected to
4.5. Preparation of 4 from 3-(diphenylphosphino)indene
To a solution of 3-(diphenylphosphino)indene (6.0 g,
2 mmol) in tetrahydrofuran (100 ml) at −80°C was
added a solution of n-BuLi (12.5 ml, 1.6 M, 2 mmol).
After 1 h, FeCl2 (1.26 g, 1 mmol) was added and the
reaction mixture stirred for 2 h at ambient temperature.
The solvent was removed in vacuo and the residue
chromatographed on silica gel with a 10:1 mixture of
cyclohexane/ethylacetate. The dark green 4 was recrys-
tallised from toluene to give 2.6 g (40% yield) of product.
˚
better than 0.8 A resolution. Processing was carried out
by use of the program SAINT [22] which applied Lorentz
and polarisation corrections to three-dimensionally in-
tegrated diffraction spots. The program SADABS [23]
was utilised for the scaling of diffraction data, the
application of a decay correction, and empirical ab-
sorption correction based on redundant reflections. The
structures for 2 and 5a were solved by the direct
methods procedure, the 5b structure was solved by the
Patterson method procedure in the SHELXTL program
library [24]. The structures were refined by least-squares
methods on F2 with anisotropic thermal parameters for
all non-hydrogen atoms. Hydrogen atoms were added
as riding contributors at calculated positions, with
isotropic thermal parameters based on the attached
carbon atom. Crystal data and structure refinement
parameters are given in Table 3.
4.6. Preparation of meso- and rac-tetracarbonyl(bis(1-
diphenylphosphinoindenyl)iron(II))molybdenum(0) (5a
and 5b)
To a solution of 4 (0.89 g, 0.1 mmol), prepared from
3-(diphenylphosphino)indene, in tetrahydrofuran (50
ml) was added Mo(CO)4(piperidine)2 (0.38 g, 0.1 mmol).
The solution was then heated to reflux for 2 h, the solvent
removed in vacuo, and the dark green residue chro-
matographed with 1:1 cyclohexane/ethylacetate. Recrys-
tallisation from CH2Cl2/heptane gave 0.052 g (40% yield)
of the meso isomer 5a as dark green/red crystals. Starting
with 4 prepared from the diphosphine 1, crystals of the
racemic isomer 5b, with identical spectral properties,
5. Supplementary material
Tables of crystal data, structure refinement details,
atomic coordinates, bond lengths and angles, an-
isotropic displacement parameters, and hydrogen coor-
dinates are available from the authors or from the
Cambridge Crystallographic Data Centre, Lensfield
Road, Cambridge, CB2 1EW, United Kingdom.
1
were isolated. H-NMR (CDCl3): l 3.68 (s, 2H, H-1),
4.31 (s, 2H, H-2), 6.4–7.4 (m, 28H, H5–H8 and Ph).
13C{1H}-NMR (CDCl3): l 66.8 (s, C-1), 76.4 (s, C-3),
3
79.9 (t, JPC=5 Hz, C-2), 87.1 (s, C-9), 89.7 (s, C-4),
124.9 (s, C-7), 125.1 (s, C-6), 127.8 (t, 3JPC=5 Hz,
3
m-Ph), 128.3 (t, JPC=5 Hz, m-Ph), 129.1 (s, C-5 or
C-8), 129.1 (s, C-5 or C-8), 129.4 (s, p-Ph), 129.9 (s,
p-Ph), 132.4 (t, 2JPC=7 Hz, o-Ph), 134.4 (d, 2JPC=7 Hz,
o-Ph), 135.0 (m, ipso-Ph), 139.0 (m, ipso-Ph). 31P{1H}-
Acknowledgements
NMR
(CDCl3):
l
33.1.
Anal.
Calc.
for
D.B. wishes to thank the Alexander von Humboldt
Foundation for a Feodor Lynen fellowship. D.E.B. and
J.B. would like to thank the University of Victoria for
C46H32FeMoO4P2: C, 61.44; H, 4.01. Found: C, 62.07;
H, 3.66. Mass spectra: (FAB, m/z (%)): 864 (3, M+)

256
J.J. Adams et al. / Journal of Organometallic Chemistry 580 (1999) 245–256
study leave and leave of absence, respectively, and the
University of Canterbury for their generous hospitality.
Dr Bryce Williamson (University of Canterbury) is
thanked for useful discussions.
press. (c) J.R. Butchard, O.J. Curnow, S.J. Smail, J. Organomet.
Chem. 541 (1997) 407.
[7] R. Aumann, B. Jasper, R. Fro¨hlich, Organometallics 14 (1995)
231.
[8] K.H. Do¨tz, I. Pruskil, U. Schubert, K. Ackermann, Chem. Ber.
116 (1983) 2337.
[9] K.A. Fallis, G.K. Anderson, N.P. Rath, Organometallics 11
(1992) 885.
[10] (a) C.J. Schaverien, R. Ernst, W. Terlouw, P. Schut, O. Sudmei-
jer, P.H.M. Budzelaar, J. Mol. Catal. A Chem. 128 (1998) 245.
(b) Hoechst A.-G. (M. Riedel, G. Erker, B. Bosch, A. Bertuleit),
DE 19632919 (1998); Chem. Abstr. 128, 205237. (c) Dow Chem-
ical Company (J. Klosin, W.J. Kruper, P.N. Nickias, J.T. Pat-
ton, D.R. Wilson), WO 9806727 (1998); Chem. Abstr. 128,
167818. (d) Bayer A.-G. (K.-H.A.O. Starzewski, W.M. Kelly, A.
Stumpf), WO 9801487 (1998); Chem. Abstr. 128, 141901. (e)
Bayer A.G. (K.-H.A.O. Starzewski, W.M. Kelly, A. Stumpf),
WO 9801486 (1998); Chem. Abstr. 128, 141900. (f) Bayer A.-G.
(K.-H.A.O. Starzewski, W.M. Kelly, A. Stumpf), WO 9801484
(1998); Chem. Abstr. 128, 141177. (g) Bayer A.-G. (K.-H.A.O.
Starzewski, W.M. Kelly, A. Stumpf), WO 9801485 (1998);
Chem. Abstr. 128, 128392. (h) Bayer A.-G. (K.-H.A.O.
Starzewski, W.M. Kelly, A. Stumpf, C. Schmid), WO 9801483
(1998); Chem. Abstr. 128, 128391. (I) Bayer A.-G. (K.-H.A.O.
Starzewski, W.M. Kelly), DE 19627064 (1998); Chem. Abstr.
128, 115367.
[11] M. Stradiotto, C.M. Kozak, M.J. McGlinchey, J. Organomet.
Chem. 564 (1998) 101.
[12] T. Hayashi, in: A. Togni, T. Hayashi (Eds), Ferrocenes: Homo-
geneous Catalysis, Organic Synthesis, Materials Science, VCH,
Weinheim, 1995, pp. 105–142.
[13] (a) T. Hayashi, A. Yamamoto, M. Hojo, Y. Ito, J. Chem. Soc.
Chem. Commun. (1989) 495. (b) T. Hayashi, A. Yamamoto, M.
Hojo, K. Kishi, Y. Ito, E. Nishioka, H. Miura, K. Yanagi, J.
Organomet. Chem. 370 (1989) 129.
[14] W. McFarlane, D.S. Rycroft, J. Chem. Soc. Dalton Trans.
(1973) 2162.
References
[1] (a) R. Broussier, G. Delmas, P. Peron, B. Gautheron, J.L.
Petersen, J. Organomet. Chem. 511 (1996) 185. (b) W.A. Schenk,
T. Gutman, J. Organomet. Chem. 544 (1997) 69. (c) D. Morcos,
W. Tikkanen, J. Organomet. Chem. 371 (1989) 15.
[2] K.-S. Gan, T.S.A. Hor, in: A. Togni, T. Hayashi (Eds.), Fer-
rocenes: Homogeneous Catalysis, Organic Synthesis, Materials
Science, VCH, Weinheim, 1995, pp. 3–104.
[3] For recent examples of complexes containing two-atom-bridged
phosphino-cyclopentadienyl ligands see: (a) M.D. Fryzuk, S.S.H.
Mao, P.D. Duval, S.J. Rettig, Polyhedron 14 (1995) 11. (b) N.E.
Schore, J. Am. Chem. Soc. 101 (1979) 7410. (c) J. Foerstner, A
Kakoschke, D. Stellfeldt, H. Butenscho¨n, R. Wartchow,
Organometallics 17 (1998) 893. (d) J.C. Leblanc, C. Moise, A.
Maisonnat, R. Poilblanc, C. Charrier, F. Mathey, J. Organomet.
Chem. 231 (1982) C43. (e) I. Lee, F. Dahan, A. Maisonnat, R.
Poilblanc, J. Organomet. Chem. 532 (1997) 159. (f) T. Cuenca,
J.C. Flores, P. Royo, J. Organomet. Chem. 462 (1993) 191.
[4] For examples of one-atom-bridged phosphino-cyclopentadienyl
ligands see: (a) D.M. Bensley, E.A. Mintz, J. Organomet. Chem.
353 (1988) 93. (b) G. Marr, T.M. White, J. Chem. Soc. Perkin
Trans. 1 (1973) 1955. (c) J.A. Miguel-Garcia, H. Adams, N.A.
Bailey, P.M. Maitlis, J. Organomet. Chem. 413 (1991) 427. (d)
M. Sawamura, H. Hamashima, M. Sugawara, R. Kuwano, Y.
Ito, Organometallics 14 (1995) 4549. (e) M. Sawamura, H.
Hamashima, Y. Ito, Tetrahedron Asym. 2 (1991) 593. (f) N.C.
Zanetti, F. Spindler, J. Spencer, A. Togni, G. Rihs,
Organometallics 15 (1996) 860. (g) Y. Yamamoto, T. Tanase, I.
Mori, Y. Nakamura, J. Chem. Soc. Dalton Trans. (1994) 3191.
(h) S. Hoppe, H. Weichmann, K. Jurkschat, C. Schneider-
Koglin, M. Dra¨ger, J. Organomet. Chem. 505 (1995) 63. (i) N.J.
Goodwin, W. Henderson, B.K. Nicholson, J. Chem. Soc. Chem.
Commun. (1997) 31.
[15] T.S.A. Hor, L.-T. Phang, J. Organomet. Chem. 373 (1989) 319.
[16] I.R. Butler, W.R. Cullen, T.-J. Kim, S.J. Rettig, J. Trotter,
Organometallics 4 (1985) 972.
[17] A. Houlton, P.T. Bishop, R.M.G. Roberts, J. Silver, M. Herber-
hold, J. Organomet. Chem. 364 (1989) 381.
[18] R. Benn, A. Rufinska, M.S. Kralik, R.D. Ernst, J. Organomet.
Chem. 375 (1989) 115.
[19] L.D. Quin, in: J.G. Verkade, L.D. Quin (Eds.), Phosphorus-31
NMR Spectroscopy in Stereochemical Analysis: Organic Com-
pounds and Metal Complexes, VCH, Deerfield Beach, FL, 1987,
pp. 391–424.
[5] For examples of complexes containing three-atom-bridged phos-
phino-cyclopentadienyl ligands see: (a) D.M. Bensley, E.A.
Mintz, S. Sussangkarn, J. Org. Chem. 53 (1988) 4417. (b) M.J.
Atherton, J. Fawcett, J.H. Holloway, E.G. Hope, A. Karac¸ar,
D.R. Russell, G.C. Saunders, J. Chem. Soc. Chem. Commun.
(1995) 191. (c) L.P. Barthel-Rosa, V.J. Catalano, K. Maitra, J.H.
Nelson, Organometallics 15 (1996) 3924.
[6] (a) O.J. Curnow, G. Huttner, S.J. Smail, M.M. Turnbull, J.
Organomet. Chem. 524 (1996) 267. (b) J.J. Adams, O.J. Curnow,
G. Huttner, S.J. Smail, M.M. Turnbull, J. Organomet. Chem. in
[20] D.J. Darensbourg, R.L. Kump, Inorg. Chem. 17 (1978) 2680.
[21
[22
[23
[24
]
]
]
]
SMART V 5.045 Bruker AXS 1998.
SAINT V 5.01 Bruker AXS 1998.
SADABS V 5.01 Sheldrick G.M. Bruker AXS 1998.
SHELXTL V 5.1 Sheldrick G.M. Bruker AXS 1998.
.