η6-Arene-cobalt(I) complexes

Article abstract of DOI:10.1016/S0022-328X(98)00839-0

(η⁶-Arene)Co(I) complexes stabilized by bisphosphines, e.g. [(η⁶-MeC₆H₅)Co(Pr₂ ⁱPC₂H₄PPr₂ⁱ)] ⁺BF₄^-, have been prepared by reacting (η³-cyclooctenyl)Co(bisphosphine) species with HBF₄ in the presence of an arene. The (η⁶-C₆H₆)Co(I) compounds can also be prepared by hydrogen abstraction from the corresponding (η⁵-cyclohexadienyl)Co(I) complex or by hydrogenation of (η³-cyclooctenyl)Co(II) species in the presence of benzene. Facile arene-exchange occurs upon treatment of these compounds with a second arene. In contrast, (η³-cyclohexenyl)Co(I) and (η⁵-cycloheptadienyl)Co(I) complexes are oxidized by HBF₄ in the presence of an alkene to give (η³-cyclohexenyl)Co(II) and (η⁵-cycloheptadienyl)Co(II) species: the former have been characterized as their diamagnetic NO adducts and the latter by a crystal structure determination.

Full text of DOI:10.1016/S0022-328X(98)00839-0

Journal of Organometallic Chemistry 568 (1998) 205–211
p6-Arene–cobalt(I) complexes
G. Großheimann 1, S. Holle, P.W. Jolly *
Max-Planck-Institut fu¨r Kohlenforschung, Kaiser-Wilhelm Platz 1, D-45466 Mu¨lheim an der Ruhr, Germany
Received 28 April 1998
Abstract
(p6-Arene)Co(I) complexes stabilized by bisphosphines, e.g. [(p6-MeC6H5)Co(Pri2PC2H4PPr2i )]+BF4−, have been prepared by
reacting (p3-cyclooctenyl)Co(bisphosphine) species with HBF4 in the presence of an arene. The (p6-C6H6)Co(I) compounds can
also be prepared by hydrogen abstraction from the corresponding (p5-cyclohexadienyl)Co(I) complex or by hydrogenation of
(p3-cyclooctenyl)Co(II) species in the presence of benzene. Facile arene-exchange occurs upon treatment of these compounds with
a second arene. In contrast, (p3-cyclohexenyl)Co(I) and (p5-cycloheptadienyl)Co(I) complexes are oxidized by HBF4 in the
presence of an alkene to give (p3-cyclohexenyl)Co(II) and (p5-cycloheptadienyl)Co(II) species: the former have been characterized
as their diamagnetic NO adducts and the latter by a crystal structure determination. © 1998 Elsevier Science S.A. All rights
reserved.
Keywords: Cobalt; Arene; Benzene; Allyl; Dienyl
1. Introduction
dienyl)Co(I) complexes react with hydride-abstraction
to give [(p6-C6H6)Co(bisphosphine)]+BF4− species.
(p6-Arene)Co(I) complexes are rare; as far as we are
aware examples are confined to the tetraphenylborate
complex 1 [2] and a series of (p6-arene)(p4-diene)Co(I)
compounds, e.g. 2 [3,4], which moreover react with
donor ligands with arene displacement, and we there-
In an earlier publication [1] we reported that treat-
ment of the (p3-cyclooctenyl)Co(bisphosphine) com-
plexes with HBF4 in the presence of an alkene results in
the oxidation of the metal to give novel, paramagnetic
organocobalt(II) species (Eq. 1).
Attempts to extend the scope of this reaction (which
is suggested to proceed by homolytic cleavage of a
Co–C bond in an intermediate Co–alkyl species) have
now shown that whereas the bisphosphine-stabilized
(p3-allyl)Co(I), (p3-cyclohexenyl)Co(I) and (p5-cyclo-
heptadienyl)Co(I) compounds react with HBF4 in a
manner similar to that shown above, the (p5-cyclohexa-
fore decided to explore this class of compound further
in anticipation that the bisphosphine stabilized deriva-
tives would act as a convenient source of the electroni-
cally and coordinatively unsatuated (bisphosphine)Co
(I) fragment for stoichiometric and catalytic reactions.
* Corresponding author. Fax: +49 208 3062980.
1 Part of the doctoral thesis submitted to the Ruhr-Universita¨t-
Bochum, 1996.
0022-328X/98/$19.00 © 1998 Elsevier Science S.A. All rights reserved.
PII S0022-328X(98)00839-0

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G. Großheimann et al. / Journal of Organometallic Chemistry 568 (1998) 205–211
similar to that confirmed by X-ray diffraction for (p5-cy-
2. Results and discussion
clohexadienyl)Co(Cy2PC2H4PCy2) [5]. Treatment of 7
with HBF4 (or Ph3CBF4) does not result in H-abstraction
(to give a (p6-cycloheptatriene)Co(I) species), instead
oxidation occurs to give [(p5-cycloheptadienyl)Co-
(Cy2PC2H4PCy2)]+BF4− (8) and here again, high yields
are obtained only if the reaction is carried out in the
The (p3-cyclohexenyl)Co(I) complex 4, which has been
reported previously [5] as the product of the reaction
between the (p3-cyclohexenyl)Co(I) species 3 and the bis-
phosphine, reacts with HBF4 in the presence of alkenes
such as butadiene with oxidation to give 5 (Eq. 2).
The corresponding Cy2PC3H6PCy2-stabilized species
[5] react similarly. Both compounds react with NO to give
diamagnetic adducts (e.g. 6) and their NMR spectra
indicate that these have structures similar to that of
[(p3-cyclooctenyl)Co(Cy2PC2H4PCy2)(NO)]+BF4−
whose crystal structure has been reported [1].
presence of an auxiliary alkene (butadiene). As expected
for a low spin Co(II) species, 8 is paramagnetic with a
magnetic moment of 1.6 BM (Evans method). The crystal
structure has been determined by X-ray diffraction and
the molecular structure of the cation is shown in Fig. 1
(the BF4 anion is disordered and has been included in the
refinement with a 50% occupancy factor for the F-
atoms). The two P-atoms and the centre of the pentadi-
enyl fragment adopt a distorted trigonal arrangement
around the Co-atom with a plane through the central
C-atom and the two P-atoms. The five pentadienyl
˚
C-atoms are coplanar and the centre lies 1.574 A from
the metal atom. The C1/C7/C6/C5- and the pentadienyl
planes form a dihedral angle of 42.1° to each other.
If the reaction between the (p3-cyclooctenyl)Co(I)
species and HBF4 shown in Eq. 1 is carried out in
thepresence of an arene instead of an alkene, the oxida-
tion is suppressed and instead a conventional protonol-
ysis occurs to give a (p6-arene)Co(I) species in high yield
We next turned our attention to the (p5-cycloheptadi-
enyl)Co(I) species. The appropriate Co(I) compound 7
was prepared in high yield by reacting the bisphosphine-
stabilized (p3-cyclooctenyl)Co(I) compound with cyclo-
heptatriene (Eq. 3).
The observation of only four signals for the 7-ring
C-atoms of the cycloheptadienyl group in the 13C-NMR
(Eq. 4). This reaction has been used to prepare the
majority of the compounds
(p3-cyclo-C8H13)Co(R2P(CH2)nPR2)+HBF4+arene“[(p6-arene)Co(R2P(CH2)nPR2)]+BF4− +C8H14
(4)
spectrum of 7 and a double doublet in the 31P-NMR
spectrum (AB spin system) indicate that the compound
has a symmetrical structure, with a mirror plane through
the central C-atom of the ring and the two P-atoms,
shown in Table 1 and Table 3. Further examples have
been prepared by arene exchange from the (p6-
C6H6)Co(I) or (p6-toluene)Co(I) species and excess of a
second arene (Eq. 5).

G. Großheimann et al. / Journal of Organometallic Chemistry 568 (1998) 205–211
207
Fig. 1. The molecular structure of [(p5-cyclo-C7H9)Co(Cy2PC2H4PCy2)]+BF4− (8) showing only the complex cation. Selected bond distances and
˚
angles: Co–P1 2.237(1), Co–P2 2.217(1), Co–C1 2.199(4), Co–C2 2.064(5), Co–C3 2.069(5), Co–C4 2.120(5), Co–C5 2.230(5), Co–D1 1.574 A;
P1–Co–P2 88.6(1), C1–Co–C5 80.3(2), C2–Co–C4 73.1(2), C3–Co–P1 100.3(1), C1–C2–C3 122.5(5), C2–C3–C4 123.9(4), C3–C4–C5
128.6(5), C4–C5–C6 129.0(5), C1–C7–C6 113.4(4), C7–C6–C5 114.5(5)°.
These exchange reactions only proceed satisfactorily in
acetone suggesting that they are assisted by solvent
complexation.
In addition to these two general preparative reactions,
individual (p6-arene)Co(I) compounds have been pre-
pared by hydride abstraction from the corresponding
(p5-cyclohexadienyl)Co(I) and by hydrogenation of an
(p3-allyl)Co(II) species in the presence of the arene
(Eq.6).
The ease with which arene exchange occurs in these
compounds suggest that they should act as a convenient
source of the [(R2P(CH2)nPR2)Co]+ fragment for stoi-
chiometric and catalytic reactions and indeed they do
show catalytic activity for the dimerization of butadiene
at 60°C whereby [(p6-MeC6H5)Co(Cy2PC2H4PCy2)]+
BF4− has the highest activity with cycloocta-1,5-diene as
the principal product. This aspect will be pursued further.
The
[(p6-arene)Co(R2P(CH2)nPR2)]+BF4−
com-
3. Experimental section
pounds are diamagnetic and their NMR spectroscopic
data are collected together in Table 1. A crystal structure
analysis of [(p6-ClC6H5)Co(Cy2PC2H4PCy2)]+BF4− has
confirmed the p6-complexation of the arene molecule to
the Co-atom; unfortunately the presence of disordered
solvent molecules in the crystal prevented a satisfactory
refinement of the data [6].
The organocobalt complexes described below are
air sensitive and all reactions were carried out in an
atmosphere of argon. Samples of [(p3-cyclo-C8H13)-
Co(R2P(CH2)nPR2)]+BF4− and [(p3-2-BuiC3H4)Co(Cy2-
PC3H6PCy2)]+BF4− were prepared by oxidation of the

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G. Großheimann et al. / Journal of Organometallic Chemistry 568 (1998) 205–211
Table 1
NMR spectroscopic data for [(p6-arene)Co(R2P(CH2)nPR2)]+BF−4 and related compoundsa
Arene
C6H6
Bisphosphine
1H-NMR (arene)
13C-NMR (arene)
31P-NMR
Cy2PCH2PCy2
Cy2PC2H4PCy2
Cy2PC3H6PCy2
Pri2PC2H4PPri2
Pri2PC3H6PPri2
Cy2PCH2PCy2
Cy2PC2H4PCy2
Cy2PC2H4PCyd2
Cy2PC3H6PCy2
Pri2PC2H4PPri2
Pri2PC2H4PPri2f
Pri2PC3H6PPri2
Cy2PC2H4PCy2
Pri2PC2H4PPri2
Pri2PC3H6PPri2
Cy2PC2H4PCy2
Cy2PC2H4PCy2
6.36
6.36
6.43
92.1
91.1
90.5
92.3
−0.28
98.3
31.0
6.38
107.0
39.3
6.44b
92.1
MeC6Hc6
2.45(Me), 6.13(2/3), 6.65(4)b
2.55(Me), 5.95(2), 6.03(3), 6.96(4)
2.55(Me), 5.95(2), 6.03(3), 6.96(4)
6.9(br)
21.2(Me), 109.3(1), 91.5(2), 89.3(3), 93.2(4)b
20.9(Me), 90.7(2), 88.5(3), 96.7(4)
20.9(Me), 113.3(1), 90.7(2), 88.5(3), 96.7(4)
—
−0.3b
97.2
97.2
29.1e
2.51(Me), 5.95(2), 6.03(3), 6.97(4)b
2.56(Me), 6.0(2/3), 6.97(4)
2.56(Me), 5.8(2), 5.9(3), 7.0(4)b
2.39(Me), 5.31(2), 6.77(3)
2.40(Me), 5.40(2), 6.69(3)
2.39(Me), 4.92(2), 7.16(3)b
1.31(Me), 5.6(2)b
19.8(Me), 112.0(1), 89.5(2), 87.4(3), 95.6(4)b
20.7(Me), 90.7(2), 88.4(3), 96.5(4)
21.8(Me), 114.6(1), 89.9(2), 87.4(3), 96.6(4)b
19.0(Me), 115.1(1), 94.7(2), 83.6(3)
19.4(Me), 112.2(1), 94.4(2), 84.5(3)
114.4(1), 94.3(2), 81.0(3)b
31.2(Me), 35.0/150.0(But), 119.5(2)b
16.6(Me), 131.7b
106.4b
106.5
38.3/33.5b
95.7
1,2-Me2C6Hg4
104.9
44.7/33.5b
76.0b
75.5b
106.2
1,3,5-But3C6H3
Me6C6
2.18(Me)b
2.24(Me), 4.10(CH2), 5.97(2),
6.06(3), 7.04(4)
MeCOCH2C6H5 Pri2PC2H4PPr2i
204.6/48.0(COCH2), 109.1(1), 90.8(2), 88.1(3),
96.4(4)b
MeOC6H5
H2NC6H5
O2NC6H5
ClC6H5
Cy2PCH2PCy2
Pri2PC2H4PPri2
Pri2PC2H4PPri2
Cy2PCH2PCy2
3.96(Me), 6.11/6.19(br)
6.10/5.97/5.84/5.73, 5.47/2.55(NH)
Broad
56.5(Me), 89.6(2), 88.3(3), 91.9(4)
76.4(2), 88.4(3), 85.8(4)b
Broad
0.48
105.4b
65.63
6.4(2/3), 6.5(4)
92.7(2), 90.3(3)
0.12/−1.37
corresponding neutral species [1]. A sample of (p4-cy-
clo-C6H8)Co(Cy2PC3H6PCy2)H was prepared by react-
ing the corresponding (p5-cyclo-C6H7)Co(I) species
with cyclohexa-1,3-diene as described earlier [5]. The
NMR spectrometers used have been listed earlier as
have the details of the crystal structure determination
[1].
M+. The crystal structure has been established by
X-ray diffraction [5].
3.2. [(p3-Cyclo-C6H9)Co(Cy2PC2H4PCy2)]+BF−4 (5)
A sample of (p3-cyclo-C6H9)Co(Cy2PC2H4PCy2) (4)
(1.03 g, 1.83 mmol) was dissolved in diethyl ether (50
ml) and treated at −45°C with butadiene (5 ml) and
ethereal HBF4 (0.25 ml, 1.83 mmol). The resulting
ochre coloured precipitate was stirred for 3 h at room
temperature (r.t.), isolated and recrystallized from ace-
tone/diethyl ether to give the compound as a pink solid.
Yield 0.97 g (81% theory). Found: C, 59.3; H, 8.9; Co,
9.2; P, 9.4; B, 1.7; F, 11.5. C32H57CoP2.BF4 calc.: C,
59.2; H, 8.9; Co, 9.1; P, 9.5; B, 1.7; F, 11.7%. IR (KBr):
w 2925s, 2850s, 1450s; 1055 (BF4). MS (ESI): m/e 562
(M+, 100%), 481 (B5%). Magn. suscept. (veff): 2.6 vB.
3.1. (p3-Cyclo-C6H9)Co(Cy2PC2H4PCy2) (4, [5])
A sample of (p3-cyclo-C6H9)(C6H6)Co (0.73 g, 3.3
mmol) [5] and Cy2PC2H4PCy2 (1.27 g, 3.0 mmol) were
stirred in THF (20 ml) at 50°C for 4 h. The resulting
red–brown suspension was evaporated to dryness and
the residue dissolved in pentane. The filtered solution
was cooled to −78°C to give the compound as a
red–brown solid. Yield 1.14 g (67% theory). MS: m/e

G. Großheimann et al. / Journal of Organometallic Chemistry 568 (1998) 205–211
209
The compound can also be prepared by reacting 4
with Ph3CBF4 (yield 84%) whereby the formation of the
tritylium dimer and Ph3CH was confirmed spectroscop-
ically (NMR, IR).
B, 1.6; F, 11.5%. IR (KBr): w 2935s, 2846s, 1447s;
1055vs (BF4). MS (ESI): m/e 576 (M+, 100%), 495
(5%). Magn. suscept. (veff): 2.3 vB.
The same compound can be prepared (yield 83%) by
reacting Ph3CBF4 in benzene.
3.3. [(p3-Cyclo-C6H9)Co(Cy2PC3H6PCy2)]+BF−4
3.4. [(p3-Cyclo-C6H9)Co(Cy2PC2H4PCy2)(NO)]+BF−4
(6)
A sample of [(p4-cyclo-C6H8)Co(Cy2PC3H6PCy2)]H
[5] (0.18 g, 0.31 mmol) was suspended in benzene (7 ml)
and treated with C7H7BF4 (0.09 g, 0.51 mmol) and the
reaction mixture was stirred at r.t. for 8 h. The resulting
pale-beige precipitate was filtered off, washed with
toluene and dried under high vacuum. The simulta-
neous formation of bitropyl in the filtrate was confi-
rmed by IR spectroscopy. Yield 0.17 g (84% theory).
Found: C, 59.7; H, 8.7; Co, 9.1; P, 9.3: B, 1.7; F, 11.4.
C33H59CoP2 ·BF4 calc.: C, 59.7; H, 9.0; Co, 8.9; P, 9.3;
A sample of [(p3-cyclo-C6H9)Co(Cy2PC2H4PCy2)]+
BF4− [5] (0.24 g, 0.37 mmol) was dissolved in acetone
(20 ml) and treated with NO (11.6 ml, 0.52 mmol) from
a gas burette. The resulting green solution was filtered
and evaporated to dryness. The residue was crystallized
from acetone/diethyl ether. Yield 0.21 g (84% theory).
Found: C, 55.6; H, 8.8; Co, 8.9; N, 1.9; P, 8.8.
C32H57CoNOP2 ·BF4 calc.: C, 56.6; H, 8.5; Co, 8.7; N,
2.1; P, 9.1%. IR (KBr): w 2921s, 2850s, 1450s;
1752s(NO); 1053s (BF4). MS (ESI): m/e 592 (M+,
100%), 481 (B5%). 1H-NMR (d6-acetone): l 6.18
(mbr, H-2), 4.37 (mbr, H-1), 2.45 (mbr, H-3a), 2.6–1.0
(H-3b, Cy2PCH2). 13C-NMR (d6-acetone): l 95.4 (C-1),
81.5/81.3 (C-2), 18.8 (C-4); 36.9, 35.3, 28.8, 28.7, 28.1–
27.6, 27.1–26.6, 26.1, 25.8, 21.7 (Cy2PCH2). 31P-NMR
(d6-acetone, 188 K): l 84.6 brs. numbering scheme
shown below.
Table 2
2
˚
Atomic coordinates and equivalent isotropic thermal parameters (A )
for 8 with standard deviations in parentheses
Atom
x
y
z
Uaeq
Co(1)
P(1)
P(2)
B(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)
C(24)
C(25)
C(26)
C(27)
C(28)
C(29)
C(30)
C(31)
C(32)
C(33)
0.2050(1)
0.1869(1)
0.2060(1)
0.253(1)
0.1247(1)
0.0958(1)
0.2172(1)
0.3723(4)
0.1319(2)
0.0780(2)
0.0439(2)
0.0645(2)
0.1183(3)
0.1542(3)
0.1436(3)
0.1619(2)
0.2172(2)
0.2685(2)
0.2865(2)
0.3292(3)
0.3043(3)
0.2863(3)
0.2430(2)
0.2583(2)
0.2295(2)
0.2597(2)
0.3252(2)
0.3540(2)
0.3235(2)
0.0427(2)
0.0209(2)
0.4410(1)
0.2739(1)
0.3871(1)
0.0522(9)
0.5910(3)
0.5436(3)
0.5157(3)
0.5213(3)
0.5533(4)
0.6461(4)
0.6813(4)
0.1937(3)
0.2407(3)
0.4257(3)
0.5426(4)
0.5731(5)
0.5482(5)
0.4337(4)
0.4017(4)
0.4143(3)
0.3632(4)
0.3953(5)
0.3682(5)
0.4143(5)
0.3837(4)
0.2422(3)
0.1276(4)
0.1125(5)
0.1478(5)
0.2604(4)
0.2717(4)
0.2125(3)
0.2546(4)
0.1990(4)
0.2116(5)
0.1757(5)
0.2269(4)
0.035(1)
0.031(1)
0.032(1)
0.117(9)
0.053(3)
0.053(3)
0.055(3)
0.056(3)
0.058(3)
0.065(4)
0.062(3)
0.036(2)
0.034(2)
0.039(2)
0.050(3)
0.065(4)
0.073(4)
0.063(4)
0.049(3)
0.037(2)
0.045(3)
0.059(3)
0.061(3)
0.055(3)
0.047(3)
0.036(2)
0.050(3)
0.062(4)
0.062(3)
0.059(3)
0.045(3)
0.037(2)
0.044(3)
0.053(3)
0.061(3)
0.060(3)
0.047(3)
0.1506(4)
0.1297(4)
0.2179(5)
0.3310(5)
0.3769(4)
0.3643(5)
0.2533(5)
0.1974(4)
0.1600(3)
0.1015(3)
0.1398(4)
0.0542(5)
−0.0670(5)
−0.1051(4)
−0.0213(4)
0.3448(3)
0.4337(4)
0.5505(4)
0.5404(5)
0.4504(4)
0.3330(4)
0.2916(39)
0.2654(4)
0.3516(4)
0.4754(4)
0.5012(4)
0.4157(4)
0.0430(3)
0.0251(4)
−0.0925(4)
−0.1892(4)
−0.1731(4)
−0.0542(4)
3.5. [(p3-Cyclo-C6H9)Co(Cy2PC3H6PCy2)(NO)]+BF−4 )
Prepared as a green solid (yield 87%) as described
above by reacting [(p3-cyclo-C6H9)Co(Cy2PC3H6-
PCy2)]+BF4− with NO in acetone. Found: C, 56.3; H,
8.5; Co, 8.4; N, 1.9; P, 8.9. C33H59CoNOP2 ·BF4
calc.: C, 57.2; H, 8.6; Co, 8.5; N, 2.0; P, 8.9%.
IR (KBr): w 2932s, 2854s, 1450s; 1745s (NO), 1055s
(BF4). MS (ESI): m/e 606 (M+, 100%). 1H-NMR
(d6-acetone): l 6.28 (mbr, H-2), 4.53 (mbr, H-1),
2.32 (mbr, H-3a); 2.5–1.1 (H-3b, Cy2PC3H6). 13C-NMR
(d6-acetone): l 97.8 (C-1), 83.7 (C-2), 20.1/19.5 (C-4/
CH2); 39.9, 36.5, 29.1, 28.6-28.5, 28.2, 27.7–27.5, 27.3–
27.1, 26.3, 26.0, 17.8 (Cy2PC3H6). 31P-NMR (d6-acetone,
188 K): l 25.4 brs. numbering scheme see above.
−0.0266(3)
−0.0057(3)
0.0168(3)
0.0652(2)
0.0651(2)
0.0037(2)
−0.0208(2)
0.0192(2)
0.0812(2)
0.1056(2)
a
U
eq=1/3 ꢀi ꢀj Uija*a* ꢀi ꢀj.
i
j

210
G. Großheimann et al. / Journal of Organometallic Chemistry 568 (1998) 205–211
Table 3
[(p6-Arene)Co(R2P(CH2)nPR2)]+X− compounds
Arene
C6H6
Bisphosphine
X−
Preparation (yield%)a Elemental analysis (calc.%)
MS (m/e, Int.%)
C
H
Co
9.2(9.3)
9.0(9.1)
9.1(8.9)
12.2(12.1)
11.6(11.8)
9.1(9.1)
9.0(8.9)
7.9(8.2)
8.9(8.8)
11.9(11.8)
11.3(11.4)
9.7(8.9)
P
Cy2PCH2PCy2
BF4
A(91)
58.9(58.9)
58.8(59.5)
59.9(60.0)
49.5(49.4)
50.5(50.4)
57.7(59.4)
59.9(60.0)
57.6(56.5)
57.3(60.5)
50.3(50.4)
51.3(51.2)
—
8.4(8.2)
8.5(8.4)
8.6(8.6)
7.9(7.8)
7.8(8.0)
8.4(8.4)
8.6(8.5)
7.9(7.8)
8.7(8.6)
8.1(8.0)
8.4(8.5)
—
9.8(9.8)
9.6(9.6)
9.4(9.4)
12.7(12.8)
12.6(12.4)
9.6(9.6)
9.4(9.4)
8.4(8.6)
9.1(9.2)
544 (M+–H, 50)
559 (M+, 100)
570 (M+–3H, B5)
—
Cy2PC2H4PCy2 BF4
Cy2PC3H6PCy2 BF4
A(93), C(88), D(64)
A(87), C(80), D(83)
A(50)
A(72)
A(90)
Pri2PC2H4PPri2
Pri2PC3H6PPri2
Cy2PCH2PCy2
BF4
BF4
BF4
410 (M+–3H, 100)
558 (M+–H, 40)
573 (M+–H, 15)
Dec.
MeC6H5
Cy2PC2H4PCy2 BF4
Cy2PC2H4PCy2 SO3CF3 D(99)
Cy2PC3H6PCy2 BF4
A(89)
A(63)
A(92)
A(62), B(94)
B(80)
586 (M+–H, 33)
Pri2PC2H4PPri2
1,2-Me2C6H4 Pri2PC2H4PPr2i
MeOC6H5 Cy2PCH2PCy2
BF4
BF4
BF4
12.3(12.4)
12.1(12.0)
9.1(9.4)
500 (M+
)
—
—
a A: protonolysis of (p3-cyclo-C8H13)Co(I) species, B: arene-exchange, C: deprotonation of (p5-cyclo-C6H7)Co(I) species, D: hydrogenation of
(p3-allyl)Co(II) species.
3.6. [(p5-Cyclo-C7H9)Co(Cy2PC2H4PCy2) (7)
sample of (p3-cyclo-C8H13)Co(Cy2PC2H4PCy2)
(1.43 g, 2.42 mmol) was dissolved in THF (20 ml) and
treated at −40°C with butadiene (ca. 5 ml) and ethe-
real HBF4 (0.33 ml, 2.41 mmol). The reaction mixture
was warmed to r.t. and stirred for 12 h. The resulting
orange–brown solid was isolated and crystallized from
acetone/diethyl ether. Yield 1.47 g (92% theory).
Found: C, 59.8; H, 8.7; Co, 8.9; P, 9.6; B, 1.7; F, 11.4.
C33H57CoP2 ·BF4 calc.: C, 59.9; H, 8.7; Co, 8.9; P, 9.4;
B, 1.6; F, 11.5%. IR (KBr): w 2930s, 2850s, 1450s;
1054vs (BF4). MS (FAB): m/e 574 (M+, 50%). Magn.
suscept. (veff): 1.6 vB.
A
(0.81 g, 1.47 mmol) and 1,3,5-cycloheptatriene (2.0 ml)
were dissolved in THF (5 ml) and stirred at r.t. for 18
h to give a red–brown suspension (a parallel experi-
ment was successful only after the introduction of
hydrogen). The reaction mixture was evaporated to
dryness and the residue crystallized from THF. Yield
0.73 g (86% theory). The presence of 1,3-cyclooctadiene
and cyclooctene in the solvent was confirmed by GC.
Found: C, 68.9; H, 9.9; Co, 10.5; P, 10.9. C33H57CoP2
calc.: C, 69.0; H, 10.0; Co, 10.3; P, 10.8%. IR (KBr): w
2920s, 2850s, 1440s; 1000s. MS (EI, 140°C): m/e 574
(M+, 100%), 481 (B5%), 398 (5%), 1H-NMR (d8-
toluene, 300 K): l 5.17 (mbr, H-2), 5.09 (mbr, H-1),
4.26 (mbr, H-3), 2.21 (mbr, H-4a), 1.67 (mbr, H-4b);
2.0–0.9 (Cy2PCH2). 13C-NMR (d8-toluene, 300 K): l
91.6 (C-2), 86.6 (C-1), 71.2 (C-3), 36.8, (C-4); 38.0, 37.8,
29.1–27.7, 27.2. 31P-NMR (d8-toluene, 185 K): l 106.5,
79.4, J (A,B) 22.2 numbering scheme shown below.
Suitable crystals were grown from chlorobenzene/di-
ethyl ether solution. Crystal structure analysis: molecu-
lar formula C33H57CoP2BF4, molecular weight 661.51 g
mol−1, crystal colour red, crystal size 0.42×0.32×
˚
0.18 mm, a=11.870(4), b=22.726(4), c=13.023(1) A,
3
˚
i=103.14(1)°, V=3421.4 A , T=293 K, Dcalc. 1.28 g
cm−3, v=6.33 cm−1, Z=4, monoclinic P21/n (no.
14), Enraf-Nonius CAD 4 diffractometer, u=0.71069
˚
A, scan mode ꢀ-2q, measured reflections (9h, 9k,
+l) 8360, 7812 independent reflections, 4410 observed
reflections (I\2| (I)) for 366 refined parameters, R=
−3
˚
0.058, Rw=0.153, residual electron density 0.069 A
.
Atomic positional parameters and equivalent isotropic
thermal parameters are listed in Table 2 and the molec-
ular structure with selected bond distances and angles is
shown in Fig. 1.
3.8. [(p6-Arene)Co(R2P(CH2)nPR2)]+X− compounds
These compounds have been prepared by four differ-
ent methods (A–D). Examples are described in detail
below while the spectroscopic data and elemental
analyses for all compounds are collected together in
Table 1 and Table 3.
3.7. [(p5-Cyclo-C7H9)Co(Cy2PC2H4PCy2)]+BF−4 (8)
A sample of (p5-cyclo-C7H9)Co(Cy2PC2H4PCy2) (7)

G. Großheimann et al. / Journal of Organometallic Chemistry 568 (1998) 205–211
211
3.8.4. Method D. Hydrogenation of an (p3-allyl)Co(II)
species in the presence of arene
3.8.1. Method A. Protonolysis of an
(p3-cyclo-C8H13)Co(I) species
3.8.4.1. [(C6H6)Co(Cy2PC2H4PCy2)]+BF−4 . A sample
of [(p3-cyclo-C8H13)Co(Cy2PC2H4PCy2)]+BF4− (0.54 g,
0.80 mmol) was suspended in benzene (3.0 ml) and the
reaction vessel attached to a gas burette filled with
hydrogen. Hydrogen absorption (17.2 ml, 0.77 mmol)
led to the formation of a red–brown suspension of the
compound which was isolated and crystallized from
acetone/diethyl ether. Yield 0.33 g (64% theory). Anal.:
see Table 3. NMR spectral data: see Table 1.
3.8.1.1. [(C6H6)Co(Cy2PC2H4PCy2)]+BF−4 . A sample
of (p3-cyclo-C8H13)Co(Cy2PC2H4PCy2) (1.11 g, 1.88
mmol) was suspended in benzene (6 ml) and treated
with ethereal HBF4 (0.30 ml, 2.22 mmol) at 0°C. The
resulting red–brown solution was stirred for 2 h at
r.t., evaporated to dryness and the residue crystal-
lized from acetone/diethyl ether. Yield 1.13 g (93%
theory). Anal.: see Table 3. NMR spectral data: see
Table 1.
In addition to the compounds shown in Table 3, the
following compounds were prepared as described above
for spectroscopic purposes (Table 1): [(MeC6H5)-
Co(Pri2PC2H4PPr2i )+[B(C6H3(CF3)2-3,5)4]−, [(MeC6H5)-
Co(Pri2PC3H6PPr2i )+BF4−, [(1,2-Me2C6H4)Co(Pr2i PC3H6-
PPri2)]+BF4−, [(1,3,5-Bu3t C6H3)Co(Cy2PC2H4PCy2)]+-
BF4−, [(Me6C6)Co(Cy2PC2H4PCy2)]+BF4−.
3.8.5. [(C6H6)Co(Cy2PC3H6PCy2)]+BF−4
A sample of [(p3-2-BuiC3H4)Co(Cy2PC3H6PCy2)]+
BF4− (0.15 g, 0.18 mmol) was dissolved in benzene (2
ml) and treated with hydrogen as described above.
Yield 0.10 g (83% theory). Anal.: see Table 3. NMR
spectral data: see Table 1.
The complex [(p3-cyclo-C8H13)Co(Cy2PC3H6PCy2)]+
BF4− reacts similarly.
3.8.2. Method B. Arene-exchange
3.8.6. [(p6-MeC6H5)Co(Cy2PC2H4PCy2)]+SO3CF−3
A sample of [(p3-cyclo-C8H13)Co(Cy2PC2H4PCy2)]+
SO3CF3− (0.10 g, 0.14 mmol) was dissolved in toluene
(8 ml) and the apparatus evacuated and filled with
hydrogen (20 ml). The resulting orange solution was
stirred for 3 h, evaporated to dryness and the residue
washed with ether to give the compound as an orange
powder. Yield 0.10 g (97% theory). Anal.: see Table 3.
NMR spectral data: see Table 1.
3.8.2.1. [(MeOC6H5)Co(Cy2PCH2PCy2)]+BF−4 . A sam-
ple of [(MeC6H5)Co(Cy2PCH2PCy2)]+BF4− (0.11 g,
0.17 mmol) was dissolved in acetone (3 ml) and anisole
(3 ml) and stirred at r.t. for 16 h. The resulting orange
solution was evaporated to dryness to give the com-
pound as an orange solid. Yield 0.09 g (80% theory).
Anal.: see Table 3. NMR spectral data: see Table 1.
In addition to the compounds shown in Table 3, the
following examples were prepared in solution for spec-
troscopic purposes (Table 1): [(MeOCH2C6H5)
Co(Pri2PC2H4PPri2)+BF4−,
[(H2NC6H5)Co(Pri2PC2H4
References
PPri2)+BF4−, [(O2NC6H5)Co(Pr2i PC2H4PPr2i )]+BF4−,
[1] G. Großheimann, P.W. Jolly, Inorg. Chim. Acta 270 (1998) 60.
[2] (a) L.W. Grosser, G.W. Parshall, Inorg. Chem. 13 (1974) 1947.
(b) L.C.A. de Carvalho, M. Dartiguenave, Y. Dartiguenave,
A.L. Beauchamp, J. Am. Chem. Soc. 106 (1984) 6848.
[3] (a) J.M. Mevs, W.E. Geiger, Organometallics 15 (1996) 2350. (b)
J. Edwin, W.E. Geiger, Organometallics 3 (1984) 1910. (c) A.
Efraty, P. Maitlis, J. Am. Chem. Soc. 89 (1967) 3744. (d) G.
Herberich, W. Klein, U. Ko¨lle, D. Spiliotis, Chem. Ber. 125
(1992) 1589.
[(ClC6H5)Co(Cy2PCH2PCy2)]+BF4− by reacting the ap-
propriate [(MeC6H5)Co(R2P(CH2)nPR2)]+BF4− com-
pound and [(ClC6H5)Co(Cy2PC2H4PCy2)]+BF4−, [(1,2-
Me2C6H4)Co(Pri2PC2H4PPr2i )]+BF4− by reacting the ap-
propriate [(C6H6)Co(R2P(CH2)nPR2)]+BF4− compound.
In addition to these two principal reactions (A, B),
individual examples were also prepared by the proce-
dures described below.
[4] H. Bo¨nnemann, R. Goddard, J. Grub, R. Mynott, E. Raabe, S.
Wendel, Organometallics 8 (1989) 1941.
[5] (a) K. Jonas, Angew. Chem. 97 (1985) 292. (b) K. Jonas, J.
Organomet. Chem. 400 (1990) 165. (c) K. Jonas, Pure Appl.
Chem. 62 (1990) 1169. (d) H. Priemer, Doctoral thesis, Ruhr-
Universita¨t-Bochum (1987). (e) K. Cibura, Doctoral thesis,
Ruhr-Universita¨t-Bochum (1985).
3.8.3. Method C. Deprotonation of an
(p5-cyclo-C6H7)Co(I) species
3.8.3.1. [(C6H6)Co(Cy2PC3H6PCy2)]+BF−4 . A sample
of (p5-cyclo-C6H7)Co(Cy2PC3H6PCy2) (0.17 g, 0.30
mmol) was treated with C7H7BF4 (0.07 g, 0.39 mmol) in
benzene (5 ml) and stirred for 16 h at r.t. The resulting
red–brown precipitate was filtered off and crystallized
from acetone/diethyl ether. Yield 0.16 g (80% theory).
Anal.: see Table 3. NMR spectral data: see Table 1.
[6] Crystal structure analysis: molecular formula C32H53ClCoP2BF4,
molecular weight 680.98 g mol−1, crystal colour red, crystal size
0.73×0.66×0.63 mm, a=14.358(2), b=17.412(2), c=
3
˚
˚
18.621(1) A, V=4655.3(8) A , T=293 K, Z=6, orthorhombic
P222 (no. 19), Enraf-Nonius CAD 4 diffractometer, u=0.71069
˚
A, scan mode ꢀ-2q, measured reflections (−h, −k, 9l) 5589,
5362 independent reflections, 3026 observed reflections (I\
2|(I)) for 370 refined parameters, R=0.182, Rw=0.412, resid-
-3
˚
Similar results were obtained by reacting Ph3CBF4.
ual electron density 4.184 A .
.