Ligand exchange reactions of triphospholyl metal carbonyl complexes

Article abstract of DOI:10.1021/om001068q

Utilizing 1-triphenylstannyl-3,5-di(tert-butyl)-1,2,4-triphosphole (2) as the transfer reagent for the 1,2,4-triphospholyl ligand, the new cobalt dicarbonyl complex (η⁵-t-Bu₂C₂P₃)(CO) ₂Co (4) has been

Full text of DOI:10.1021/om001068q

Organometallics 2001, 20, 2905-2915
2905
Liga n d Exch a n ge Rea ction s of Tr ip h osp h olyl Meta l
Ca r bon yl Com p lexes†
Frank W. Heinemann,‡ Hans Pritzkow,§ Matthias Zeller,‡ and Ulrich Zenneck*,‡
Institut fu¨r Anorganische Chemie, Universita¨t Erlangen-Nu¨rnberg, Egerlandstrasse 1,
91058 Erlangen, Germany, and Institut fu¨r Anorganische Chemie, Universita¨t Heidelberg,
Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
Received December 15, 2000
Utilizing 1-triphenylstannyl-3,5-di(tert-butyl)-1,2,4-triphosphole (2) as the transfer reagent
for the 1,2,4-triphospholyl ligand, the new cobalt dicarbonyl complex (η5-t-Bu2C2P3)(CO)2Co
(4) has been prepared. The reactivity of 4 and that of triphosphacymantrene (η5-t-
Bu2C2P3)(CO)3Mn (3) toward carbonyl exchange have been investigated. When 3 or 4 are
photolyzed in the presence of phosphanes the mono- and disubstituted complexes (η5-t-
Bu2C2P3)(CO)(PR3)Co (R ) Et (5), Ph (6)) and (η5-t-Bu2C2P3)(CO)(PMe3)2Mn (7) are obtained.
In the absence of additional ligands, the irradiation of 3 in n-hexane results in the formation
of the dinuclear rac and meso complexes {µ[1:1-5-η-t-Bu2C2P3](CO)2Mn}2 (8a and 8b). Under
thermal conditions the carbonyl ligands of both 3 and 4 are replaced by isonitrile ligands to
yield (η5-t-Bu2C2P3)(CN-Cy)2Co (9), (η5-t-Bu2C2P3)(CO)(CN-Cy)Co (10), and (η5-t-Bu2C2P3)-
(CO)2(CN-Cy)Mn (11), respectively. The substances have been fully characterized including
X-ray structural analysis for the complexes 4, 6, 7, 8a , 8b, and 9. Under both photochemical
and thermal conditions the complexes 3 and 4 are much more reactive than their phosphorus-
free cyclopentadienyl analogues. In contrast with cymantrene, triphosphacymantrene (3)
seems to react via an associative pathway.
In tr od u ction
intermediate η3-bonding type.3 In recent years a number
of complexes have been synthesized containing the 3,5-
di(tert-butyl)-1,2,4-triphospholyl ligand 1. Its complex
chemistry is dominated by the η5-complexes,4-6 but it
can also function as a σ-ligand, too.7 Even a tempera-
ture-dependent equilibrium between a π-bonded η5- and
a σ-bonded η1-nickel complex has been observed.8
However, not only does the introduction of phosporus
atoms offer novel structural features but the electronic
structure of the compounds is influenced significantly
as well. Thus hexaphosphamanganocene (η5-t-Bu2C2P3)2-
Mn is structurally very closely related to other manga-
nocene derivatives such as Cp*2Mn, but the electronic
ground state is different when compared to all manga-
nocene derivatives that appeared in the literature.5
This strong consequence of the phosphorus atoms on
symmetry and energy of the frontier orbitals of the
Phosphorus atoms can be incorporated in unsaturated
heterocycles to replace CR fragments as isovalent and
isolobal building blocks, and this results in the forma-
tion of numerous organic and organometallic phospho-
rus compounds in which the phosphorus atom can often
be viewed as a carbon copy.1 One of the most simple
examples of organometallic compounds containing a
phosphorus heterocyclic π-ligand is phospholyl com-
plexes, the phosphorus analogues of cyclopentadienyl
(Cp) compounds. However, in some cases the properties
of phospholyl complexes differ significantly from those
of their carbacyclic counterparts. Due to the lone pair
of the phosphorus atom, which is absent for Cp carbon
atoms of course, either the phospholyl ligand can be
π-bonded to the metal atom in an η5-fashion via the
delocalized aromatic π-system or it can act as a σ-ligand
by utilizing the phosphorus lone pair.2 Replacing more
than one CR fragment of a cyclopentadienyl ligand by
phosphorus atoms extends the structural manifold. 1,3-
Diphospholyl complexes for example may exhibit an
(3) Bartsch, R.; Hitchcock, P. B.; Nixon, J . F. J . Organomet. Chem.
1989, 373, C17-C20. Bartsch, R.; Hitchcock, P. B.; Nixon, J . F. J . Chem
Soc., Chem. Commun. 1990, 472-474.
(4) Driess, M.; Hu, D.; Pritzkow, H.; Scha¨ufele, H.; Zenneck, U.;
Regitz, M.; Ro¨sch, W. J . Organomet. Chem. 1987, 334, C35-C38.
Callaghan, Ch.; Clentsmith, G. K. B.; Cloke, F. G. N.; Hitchcock, P.
B.; Nixon, J . F.; Vickers, D. M. Organometallics 1999, 18, 793-795.
(5) Clark, T.; Elvers, A.; Heinemann, F. W.; Hennemann, M.; Zeller,
M.; Zenneck, U. Angew. Chem. 2000, 112, 2174-2178. Clark, T.; Elvers,
A.; Heinemann, F. W.; Hennemann, M.; Zeller, M.; Zenneck, U. Angew.
Chem., Int. Ed. 2000, 39, 2087-2091.
† Dedicated to Professor Marianne Baudler on the occasion of her
80th birthday.
* Corresponding author. Tel: Int. code +(9131)852-7367. E-mail:
zenneck@chemie.uni-erlangen.de.
‡ Universita¨t Erlangen-Nu¨rnberg.
(6) Bartsch, R.; Hitchcock, P. B.; Madden, T. J .; Meidine, M. F.;
Nixon, J . F.; Wang, H. J . Chem. Soc., Chem. Commun. 1988, 1475-
1476.
(7) Bartsch, R.; Carmichael, D.; Hitchcock, P. B.; Meidine, M. F.;
Nixon, J . F.; Sillet, G. J . D. J . Chem. Soc., Chem. Commun. 1988,
1615-1617. Hitchcock, P. B.; Matos, R. M.; Nixon, J . F. J . Organomet.
Chem. 1993, 462, 319-329.
(8) Heinemann, F. W.; Pritzkow, H.; Zeller, M.; Zenneck, U. Orga-
nometallics 2000, 19, 4283-4288.
§ Universita¨t Heidelberg.
(1) Dillon, K. B.; Mathey, F.; Nixon, J . F. Phosphorus, The Carbon
Copy; J ohn Wiley & Sons: Chichester, 1998.
(2) Mathey, F.; Fischer, J .; Nelson, J . H. Struct. Bonding 1983, 55,
153-201. Mathey, F. J . Organomet. Chem. 1994, 475, 25-30. Gar-
nowskii, A. D.; Sadimenko, A. P. Adv. Heterocycl. Chem. 1999, 72,
1-77. Arliguie, T.; Ephritikhine, M.; Lance, M.; Nierlich, M. J .
Organomet. Chem. 1996, 524, 293-297.
10.1021/om001068q CCC: $20.00 © 2001 American Chemical Society
Publication on Web 06/01/2001

2906 Organometallics, Vol. 20, No. 13, 2001
Heinemann et al.
Sch em e 1
a
b
Br(CO)5Mn. Co2(CO)8.
F igu r e 1. Molecular structure of 4 in the solid state.
Hydrogen atoms are omitted for clarity.
complexes implies a comparable significant influence on
the reactivity of the compounds. However, in the
literature there are only few reports on that point.9 Best
candidates for this approach seemed to be half-sandwich
compounds such as triphospholylmetal carbonyl com-
plexes. Their Cp analogues undergo a range of clean
ligand substitution reactions, which are well described
and understood.10,11 However, most previous attempts
to synthesize half-sandwich compounds of the ligand 1
carried out so far failed. There was only one report
dealing with triphospholyl rhodium(I) complexes, but
no ligand exchange reactions were carried out.6
As we found an easy access to triorganylstannyl
triphosphole derivatives such as 1-triphenylstannyl-3,5-
di(tert-butyl)-1,2,4-triphosphole (2),12 which are excel-
lent starting materials for the high-yield transfer of 1,
we started a systematic investigation on the complex
chemistry of this phosphorus-rich cyclopentadienyl de-
rivative in detail. This way (η5-t-Bu2C2P3)(CO)3Mn (3)
is formed in good yield when 2 is reacted with Br-
(CO)5Mn5 (Scheme 1). In this contribution we describe
the synthesis of the cobalt dicarbonyl complex (η5-t-
Bu2C2P3)(CO)2Co (4) and the reactivity of (η5-t-
Bu2C2P3)(CO)3Mn (3) and (η5-t-Bu2C2P3)(CO)2Co (4)
toward carbonyl substitution reactions.
this disagreement might be caused by the high reactiv-
ity of 4 toward CO-ligand exchange reactions.
As expected for a half-sandwich complex, the 31P NMR
spectrum consists of an AB2 spin system and the signals
are separated by only 2.9 ppm. In 13C NMR there is only
one signal each for the CO ligands, the ring carbon
atoms, and both types of tert-butyl carbon atoms.
Despite of its low melting point of ca. -10 °C, X-ray
quality crystals of 4 could be obtained from an n-hexane
solution at about -30 °C. The molecular structure of 4
(Figure 1, Tables 1 and 2) reveals the typical η5-bonding
situation of the t-Bu2C2P3 ring. The triphospholyl ligand
is very close to planar, and both the bond distances and
angles show no indications for a distortion.
The plane that is defined by the carbonyl ligands and
the mirror plane of the triphospholyl ligand are close
to perpendicular to each other. As suggested by the
NMR spectra, the tert-butyl groups and the adjacent
phosphorus atoms are almost equivalent in the solid
state. A small deviation is probably caused by packing
effects in the solid state. Such an arrangement is found
for Cp*(CO)2Co as well.13 The angle between the two
carbonyl groups is ca. 91°, which is again in good
accordance with the angle of ca. 94° observed for
Cp*2(CO)2Co.
Resu lts
P h otoch em ica l Ca r bon yl Exch a n ge Rea ction s of
3 a n d 4. When 4 is irradiated by visible light in the
presence of phosphanes such as PEt3 or PPh3, one
carbonyl ligand is replaced and the substitution prod-
ucts (η5-t-Bu2C2P3)(CO)(PEt3)Co (5) and (η5-t-Bu2C2P3)-
(CO)(PPh3)Co (6) can be isolated in moderate to good
yields (Scheme 2). They both exhibit AB2X 31P NMR
spectra; thus no principal structural changes of the
triphospholyl cobalt fragment are assumed. As for 4, the
splitting between the A and B signals of 5 is less than
3 ppm, but for 6 a difference of 21 ppm is observed. This
indicates a more distinct differentiation of the ring
phosphorus atoms of 6.
For investigations on the reactivity of triphospholyl-
metal carbonyl complexes we needed suitable starting
compounds. Therefore we tried to prepare a triphospha
derivative of (η5-Cp)(CO)2Co. Encouraged by the forma-
tion of (η5-t-Bu2C2P3)(CO)3Mn (3), 1-triphenylstannyl-
3,5-di(tert-butyl)-1,2,4-triphosphole (2) is reacted with
an equimolar amount of Co2(CO)8, and the target
complex (η5-t-Bu2C2P3)(CO)2Co (4) is formed. Only 20%
yield of pure material can be isolated. In contrast to
that, 31P NMR spectra of the reaction mixture indicate
an initial quantitative formation of 4. As outlined below,
5 is a red liquid at room temperature and no crystals
could be obtained, whereas 6 is a dark red solid and
X-ray suitable crystals can be grown from an n-hexane
solution at 4 °C. The molecular structure (Figure 2,
Tables 1 and 3) confirms the estimated bonding mode
with the triphospholyl moiety again being η5-bonded and
(9) Bo¨hm, D.; Heinemann, F.; Hu, D.; Kummer, S.; Zenneck U.
Collect. Czech. Chem. Commun. 1997, 62, 309-317.
(10) Strohmeier, W.; Mu¨ller, F.-J . Chem. Ber. 1967, 100, 2812-2821.
Rehder, D.; Kec¸eci, A. Inorg. Chim. Acta 1985, 103, 173-177. Werner,
H. Angew. Chem. 1983, 95, 932-954. Hart-Davis, A. J .; Graham, W.
A. G. Inorg. Chem. 1970, 9, 2658-2663.
(11) Yamamoto, Y.; Mise, T.; Yamazaki, H. Bull. Chem. Soc. J pn.
1978, 51, 2743-2744.
(12) Elvers, A.; Heinemann, F. W.; Wrackmeyer, B.; Zenneck, U.
Chem. Eur. J . 1999, 5, 3143-3153.
(13) Byers, L. R.; Dahl, L. F. Inorg. Chem. 1980, 2, 277-284.

Triphospholyl Metal Carbonyl Complexes
Organometallics, Vol. 20, No. 13, 2001 2907
Ta ble 1. Cr ysta l Da ta a n d Str u ctu r e Refin em en t of 4 a n d 6
4
6
empirical formula
fw
C
12H18CoP3
C29H33CoOP4
580.3
346.10
solvent
n-hexane
n-hexane
cryst habit
cryst size
temperature
cryst syst
space group
unit cell dimens
reddish brown plate
0.50 × 0.40 × 0.18 mm
200(2) K
triclinic
P1
dark red block
0.60 × 0.42 × 0.20 mm
298(2) K
monoclinic
P21/n
a ) 6.396(2) Å
b ) 9.787(2) Å
c ) 13.472(3) Å
R ) 96.94(2)°
â ) 98.87(3)°
γ ) 107.91(2)°
780.1(3) Å3
2
a ) 12.133(2) Å
b ) 14.947(3) Å
c ) 16.193(3) Å
R ) 90°
â ) 91.03(3)°
γ ) 90°
volume
Z
density (calcd)
F(000)
2936(1) Å3
4
1.474 g/cm3
356
1.313 g/cm3
1208
abs coeff
θ range for data collection
index ranges
1.398 mm-1
2.22-27.00°
-8 e h e 1,
-12 e k e 12,
-17 e l e 17
4242
3335 [R(int) ) 0.0332]
2421
ψ-scan
0.4611 and 0.3466
0.822 mm-1
1.85-27.00°
-15 e h e 15,
-1 e k e 19,
-1 e l e 20
7650
6413 [R(int) ) 0.0376]
3866
no
no. of reflns collected
no. of ind reflns
no. of reflns with I > 2σ(I)
abs corr
max. and min. transm
refinement method
no. of data/restraints/params
goodness-of-fit on F2
final R indices [I>2σ(I)]
R indices (all data)
largest diff peak and hole
full matrix least-squares on F2
3335/0/217
1.033
R1 ) 0.0598, wR2 ) 0.1473
R1 ) 0.0891, wR2 ) 0.1671
0.873 and -0.737 e Å-3
6413/0/415
0.852
R1 ) 0.0407, wR2 ) 0.0892
R1 ) 0.0767, wR2 ) 0.0982
0.346 and -0.354 e Å-3
Ta ble 2. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 4
Sch em e 2
Co-C(10)
Co-C(20)
P(1)-P(2)
P(2)-C(2)
P(3)-C(1)
P(3)-C(2)
P(1)-C(1)
C(10)-O(10)
C(20)-O(20)
1.747(6)
1.759(5)
2.099(2)
1.781(6)
1.759(5)
1.773(5)
1.796(5)
1.145(7)
1.142(6)
C(10)-Co-C(20)
Co-C(10)-O(10)
Co-C(20)-O(20)
P(1)-C(1)-P(3)
C(1)-P(3)-C(2)
P(3)-C(2)-P(2)
C(2)-P(2)-P(1)
P(2)-P(1)-C(1)
91.2(3)
178.6 (6)
177.9 (5)
122.3(3)
96.9(2)
123.3(3)
98.24(17)
99.24(16)
a
b
PR3, hν, 15 min. 2 equiv of CN-Cy, -60 °C f rt.
form (η5-t-Bu2C2P3)(CO)(PMe3)2Mn (7) in 74% yield
(Scheme 3). At room temperature the NMR spectra of
7 exhibit very broad lines. A coalescence phenomenon
was considered, and thus a variable-temperature NMR
experiment was applied. At -60 °C the 31P NMR
spectrum of 7 forms an ABCDE spin system with all
phosphorus atoms being different (Figure 3). The signals
of the two adjacent phosphorus atoms a and b are
separated by 52 ppm and exhibit a coupling constant
1J (31P,31P) of 432 Hz, and the two trimethylphosphane
groups are discriminated likewise and separated by 5.6
ppm. From the 31P NMR coalescence temperatures of
22 ( 5 °C for the adjacent ring phosphorus atoms and
50 ( 5 °C for the phosphane groups, the activation
energy for the rotation of the triphospholyl ring can be
the angle built up by the two co-ligands being 90.7°. In
contrast with 4, the orientation of the co-ligands is now
in parallel with the vertical mirror plane of the π-ligand
and the bulky triphenylphosphane is situated in a trans
position with respect to the single phosphorus atom P3.
This position grants the maximum of space available
for this ligand. Most probably this conformation repre-
sents the thermodynamic favorable situation in solution
as well; thus independent from a potential high barrier
of the ring rotation of the heterocycle, the differing trans
effects of CO and PPh3 ligands might explain the
differences of the chemical shifts of the 31P ring nuclei
of 6.
When the manganese complex (η5-t-Bu2C2P3)(CO)3Mn
(3) is irradiated in the presence of excess trimethylphos-
phane, two carbonyl ligands are readily displaced to
calculated to be 53.5 kJ mol-1 14
.

2908 Organometallics, Vol. 20, No. 13, 2001
Heinemann et al.
F igu r e 3. Temperature-dependent 31P{1H} NMR spectra
(161.7 MHz, [D8] toluene) of 7.
F igu r e 2. Molecular structure of 6 in the solid state.
Hydrogen atoms are omitted for clarity.
Ta ble 3. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 6
Co-C(10)
Co-P(4)
1.725(4)
2.1760(10)
2.1620(14)
1.744(3)
1.760(3)
1.773(3)
1.758(3)
1.153(4)
P(1)-P(2)
P(2)-C(2)
P(3)-C(1)
P(3)-C(2)
P(1)-C(1)
C(10)-O(10)
C(10)-Co-P(4)
Co-C(10)-O(10)
P(1)-C(1)-P(3)
C(1)-P(3)-C(2)
P(3)-C(2)-P(2)
C(2)-P(2)-P(1)
P(2)-P(1)-C(1)
90.72(11)
179.0(4)
120.54(17)
99.77(14)
121.95(18)
98.14(11)
99.59(11)
Sch em e 3
F igu r e 4. Molecular structure of 7 in the solid state.
Hydrogen atoms are omitted for clarity.
appears as a triplet, which is attributed to the interac-
tion with the two phosphorus atoms of the PMe3 ligands.
To explain the low-temperature 31P and 13C NMR
results, the molecule is assumed to be rigid and of C1
symmetry. The vertical mirror plane of ligand 1 must
be extinguished by the orientation of the co-ligands.
This assumption was corroborated by an X-ray dif-
fraction study of 7 (Figure 4, Tables 4 and 5). The
molecular structure in the solid state reveals the
unsymmetrical arrangement of the two PMe3 ligands.
When considering the comparable space-filling proper-
ties of the tert-butyl groups and the PMe3 ligands, a
sterical overcrowded situation is evident. The central
carbon atom C11 of the tert-butyl moiety, which is not
influenced by the two phosphane groups, is located close
to the plane built up by the triphospholyl ring, whereas
corresponding C21 is displaced by 27.9(3) pm. Addition-
ally the manganese carbon bond Mn-C1 is 5.5 pm
shorter than Mn-C2.
a
b
c
PMe3, hν, 15 min. hν, 15 min. Cy-NC, -70 °C, 3 h.
In accordance with the 31P NMR observations, the 13
C
NMR spectrum of 7 consists of separate lines for all
sorts of carbon atoms at low temperature. The signals
of the ring carbon atoms are separated by 4.8 ppm and
exhibit 1J (13C,31P) values, which range from 70 to 90
Hz, whereas the 13C signal of the carbonyl ligand
The triphospholyl complexes are ligands themselves.
Due to its phosphorus lone pairs 3 reacts with (thf)-
(CO)5Cr to yield the binuclear manganese chromium
complex {µ[1:1-5-η-t-Bu2C2P3]}{(CO)5Cr}{(CO)3Mn}.5
Therefore photolysis of (η5-t-Bu2C2P3)(CO)3Mn (3) with-
out addition of further ligands was attempted. Within
(14) Gu¨nther, H. NMR-Spektroskopie, Eine Einfu¨hrung in die
Protonenresonanzspektroskopie und ihre Anwendungen in der Chemie,
2nd corrected ed.; Georg Thieme Verlag: Stuttgart, New York, 1983.

Triphospholyl Metal Carbonyl Complexes
Organometallics, Vol. 20, No. 13, 2001 2909
Ta ble 4. Cr ysta l Da ta a n d Str u ctu r e Refin em en t of 7 a n d 9
7
9
empirical formula
fw
C
17H36MnOP5
C24H40CON2P3
508.42
466.28
solvent
n-hexane
n-hexane
cryst habit
cryst size
temperature
cryst syst
space group
unit cell dimens
orange rhombohedron
0.7 × 0.4 × 0.25 mm
220(2) K
monoclinic
P21/c
part of dark red needle
0.36 × 0.11 × 0.06 mm
173(2) K
rhombohedral
R3c
a ) 12.264(1) Å
b ) 10.444(1) Å
c ) 18.505(2) Å
R ) 90°
a ) 33.6732(12) Å
b ) 33.6732(12) Å
c ) 12.0325(8) Å
R ) 90°
â ) 94.66(1)°
γ ) 90°
â ) 90°
γ ) 120°
volume
Z
density (calcd)
F(000)
abs coeff
2362.4(4) Å3
4
11815.6(8) Å3
18
1.311 g/cm3
984
1.286 g/cm3
4860
0.901 mm-1
2.21-27.00°
-1 e h e 15,
-13 e k e 1,
-23 e l e 23
6538
0.850 mm-1
1.21-27.86°
0 e h e 20,
0 e k e 13,
0 e l e 22
θ range for data collection
index ranges
no. of reflns collected
no. of ind reflns
no. of reflns with I > 2σ(I)
abs corr
max. and min. transm
refinement method
no. of data/restraints/params
goodness-of-fit on F2
final R indices [I>2σ(I)]
R indices (all data)
largest diff peak and hole
26 971
5982 [R(int) ) 0.050]
4993
ψ-scan
0.928 and 0.711
5160 [R(int) ) 0.0214]
4383
ψ-scan
0.3643 and 0.3238
full matrix least squares on F2
5160/0/325
1.048
R1 ) 0.0290, wR2 ) 0.0670
R1 ) 0.0384, wR2 ) 0.0712
0.269 and -0.373 e Å-3
5982/1/431
0.927
R1 ) 0.0325, wR2 ) 0.0576
R1 ) 0.0466, wR2 ) 0.0609
0.394 and -0.203 e Å-3
Ta ble 5. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 7
Mn-C(10)
Mn-P(4)
1.762(2)
2.2785(5)
2.2643(6)
116.3(2)
2.1133(7)
1.7555(17)
1.7490(18)
1.7668(18)
1.7647(18)
Mn-P(5)
C(10)-O(10)
P(1)-P(2)
P(2)-C(2)
P(3)-C(1)
P(1)-C(1)
P(3)-C(2)
Mn-C(10)-O(10)
P(1)-C(1)-P(3)
C(1)-P(3)-C(2)
P(3)-C(2)-P(2)
C(2)-P(2)-P(1)
P(2)-P(1)-C(1)
C(10)-Mn-P(4)
C(10)-Mn-P(5)
P(4)-Mn-P(5)
179.0(2)
121.86(10)
99.64(12)
119.81(10)
100.66(6)
98.00(6)
88.45(6)
85.19(7)
94.53(2)
15 min 1 equiv of carbon monoxide is removed and
replaced by a phosphorus atom of a second triphospholyl
complex to result in the formation of homobinuclear
species. Because of σ-coordination of a manganese atom
by one of the neighboring phosphorus atoms of the
triphospholyl ring, the vertical mirror plane of the
π-ligand is lost again and the diastereomeric rac and
meso complexes 8a and 8b, {µ[1:1-5-η-t-Bu2C2P3](CO)2-
Mn}2, are isolated (Scheme 3).
Crystals suitable for X-ray analysis of both complexes
can be isolated after chromatography of the reaction
mixture. Slow solvent evaporation of a CDCl3 solution
yields crystals of the meso compound (8b). It crystallizes
in the triclinic space group P1h with two symmetrically
independent molecules in the unit cell. Both are located
on a crystallographic inversion center. Crystals of the
F igu r e 5. Molecular structures of 8a (top) and 8b (bottom)
in the solid state. Hydrogen atoms are omitted for clarity.
rac isomer (8a ) were obtained from n-hexane at 4 °C.
The space group is P21/n. Both enantiomers are present
in the unit cell. They are close to C2 symmetric (Figure
5, Tables 6, 7, and 8).
The main difference between the two diastereomers
is the orientation of the two metal-phosphorus σ-bonds.
In the case of the rac isomer 8a , both bridging P atoms
P2 and P5 point to the same side of the molecule,
whereas in the case of the meso isomer they are

2910 Organometallics, Vol. 20, No. 13, 2001
Heinemann et al.
F igu r e 6. 31P{1H} NMR spectrum (161.7 MHz, CDCl3, 23
°C) of a mixture of 8a and 8b.
F igu r e 7. Molecular structure of 9 in the solid state.
Hydrogen atoms are omitted for clarity.
orientated to opposite sides. On the other hand the bond
lengths and angles within the triphospholyl ligands of
8a and 8b are almost identical. The bond angles around
the manganese atom and the σ-bonded phosphorus
atoms differ by a maximum of 6°, and the distance
between the manganese and the σ-bonded phosphorus
atoms are 2.271(2) Å for the rac and 2.256(1) Å for the
meso isomer. These values are in good agreement with
the mean value of 2.271 Å found for the Mn-P distances
in 7.
Not only the structural but also the spectroscopic
properties of 8a and 8b point to their close relation.
Solutions of mixture of 8a and 8b exhibit only two
carbonyl stretching modes at 1962 und 1930 cm-1. This
is indicative for electronically almost identical manga-
nese centers.
between phosphorus atoms, which are not connected by
a chemical bond, point to a direct lone pair interaction
of the involved phosphorus atoms.16 An interaction of
the π-electrons is possible in both 8a and 8b, but only
for the rac isomer 8a are the lone pairs of P3 and P6,
which belong to different rings, directing toward each
other (Figure 5). The distance between P3 and P6 of 8a
is about 3.28 Å, which is less than twice the van der
Waals radius of phosphorus atoms (3.6 Å).17
Th er m a l Ca r bon yl Exch a n ge Rea ction s of 3 a n d
4. As the photochemical carbonyl exchange reactions of
3 and 4 are surprisingly fast, a thermal reaction
pathway seemed to be possible as well. When 4 is
allowed to react with phosphanes at room temperature
in solution, a slow replacement of one CO ligand is
observed. After one day there are only small amounts
of a substitution product observable in the IR. In
contrast to that, 4 reacts under the same conditions
readily with cyclohexylisonitrile and no irradiation or
heating is needed. Using 2 equiv of isonitrile leads to
the formation of two products (Scheme 2). The main one
is (η5-t-Bu2C2P3)(CN-Cy)2Co (9), which is isolated in
77% yield. The spectroscopic features resemble closely
those found for the dicarbonyl complex 4, indicating no
principal structural changes upon substitution of the
σ-ligands.
In contrast to that, 8a and 8b exhibit very different
NMR properties. Due to strong P-P coupling, the 31P
NMR spectra are influenced most and (Figure 6) two
independent sets of signals are observed. The major
meso isomer 8b generates an [ABC]2 spin system with
no significant interaction between the two halves of the
1
molecule. The J (31P,31P) coupling constant of the two
adjacent phosphorus atoms A and B is 424 Hz, and the
2J (31P,31P) values are about 40 Hz; thus the 31P NMR
parameters of 8b resemble those of 3 at low tempera-
ture. Caused by the nuclear quadrupole moment of
manganese, the signal of the σ-metal-bonded phospho-
rus atom is severely broadened.
The minor isomer 8a behaves completely different in
31P NMR, as it shows a strong interaction between the
two triphospholyl rings. Despite the fact that one of its
signals is hidden by a signal of 8b, the spin system is
assumed to be of the type AA′XX′YY′. As there is no
analytical solution for this spin system,15 the coupling
constants could not yet be determined. Nevertheless, at
least one of the coupling constants J (31P,31P) between
the two triphospholyl rings must be in the same range
as those within the five-membered rings. Because of the
quadrupole moment of the manganese atom, a coupling
mechanism along σ- and π-bonds of the metal is very
unlikely. 31P coupling constants of 40 Hz or more
9 forms crystals of two polymorphous forms, dark red
needles and yellow to brown thin plates, and both have
been analyzed by X-ray crystallography. The thin plates
were of low quality, but red needles allowed a precise
analysis (Figure 7, Tables 4 and 9). The molecular
structures of 9 in the solid state represent different
conformers; thus only the better set of data will be
discussed.18 The triphospholyl moiety is η5-bonded and
the isonitrile ligands are arranged in the same manner
(16) Baudler, M.; Du¨ster, D.; Heumu¨ller, R. In Phosphorus-31-P
NMR Spectral Properties in Compound Characterization and Struc-
tural Analysis; Quin, L. D., Verkade, J . G., Eds.; VCH: New York,
1994; pp 81-91. Baudler M.; Hahn, J .; Arndt, V.; Knoll, B.; Kazmierc-
zak, K.; Darr, E. Z. Anorg. Allg. Chem. 1986, 538, 7-20. Baudler, M.;
Reuschenbach, G.; Hahn, J . Chem. Ber. 1983, 116, 847-855.
(17) Bondi, A. J . Chem. Phys. 1964, 68, 441.
(15) Lustig, E.; Duy, N.; Diehl, P.; Kellerhals, H. J . Chem. Phys.
1968, 48, 5001-5007.
(18) The only main difference between the two structures of 9 is
the orientation of the cyclohexyl rings, which are rotated by ca. 90°.

Triphospholyl Metal Carbonyl Complexes
Organometallics, Vol. 20, No. 13, 2001 2911
Ta ble 6. Cr ysta l Da ta a n d Str u ctu r e Refin em en t of 8a a n d 8ba
8a
8b
empirical formula
fw
C
24H36Mn2O4P6
C24H36Mn2O4P6
684.23
684.23
solvent
n-hexane
CDCl3
cryst habit
cryst size
temperature
cryst syst
space group
unit cell dimens
red rhombohedron
0.55 × 0.15 × 0.10 mm
220(2) K
monoclinic
P2(1)/n
red block
0.90 × 0.50 × 0.30 mm
294(2) K
triclinic
P1h
a ) 10.606(2) Å
b ) 9.898(2) Å
c ) 29.882(6) Å
R ) 90°
a ) 11.087(1) Å
b ) 12.127(1) Å
c ) 12.226(1) Å
R ) 89.20(1)°
â ) 83.61(1)°
γ ) 72.36(1)°
1556.4(2) Å3
2
â ) 96.31(2)°
γ ) 90°
volume
Z
density (calcd)
F(000)
3118.0(11) Å3
4
1.458 g/cm3
1408
1.460 g/cm3
704
abs coeff
θ range for data collection
index ranges
1.145 mm-1
1.98-25.00°
-1 e h e 12,
-1 e k e 11,
-35 e l e 35
7271
1.147 mm-1
1.65-29.00°
-15 e h e 1,
-16 e k e 16,
-16 e l e 16
9519
no. of reflns collected
no. of ind reflns
no. of reflns with I > 2σ(I)
abs corr
max. and min. transm
refinement method
no. of data/restraints/params
goodness-of-fit on F2
final R indices [I>2σ(I)]
R indices (all data)
largest diff peak and hole
5504 [R(int) ) 0.0436]
3574
8290 [R(int) ) 0.0155]
6777
ψ-scan
0.4570 and 0.3967
0.2671 and 0.3295
full matrix least squares on F2
5504/0/433
1.016
R1 ) 0.0497, wR2 ) 0.0899
R1 ) 0.0958, wR2 ) 0.1063
0.432 and -0.493 e Å-3
8290/0/465
1.053
R1 ) 0.0338, wR2 ) 0.0832
R1 ) 0.0451, wR2 ) 0.0892
0.370 and -0.351 e Å-3
a
The unit cell of 8b contains two symmetrically independent molecules, which are both located on a crystallographic inversion center.
A disorder is observed in one of the tert-butyl groups in 8b, where two alternative sites were refined, giving a site occupancy of the major
component of 77.0(7)% for C21, C22, C23. Further information is available in the Supporting Information.
as the CO ligands of dicarbonyl complex 4. As expected
a plane is built up by the CNC-Co-CNC part of the
complex, which is orientated almost perpendicular to
the plane of the triphospholyl ring. This indicates a
preferred ligand arrangement for this type of complex
in the absence of sterical overcrowded situations. The
coordinated isonitrile ligands form almost linear Co-
C-N-C units, with Co-C-N and C-N-C bond angles
of about 178-179°.
The second reaction product is the monosubstitution
compound (η5-t-Bu2C2P3)(CO)(CNCy)Co (10), which is
formed in about 9% yield. This compound is a red to
tan liquid at room temperature. Since no crystals could
be obtained, 10 was characterized by spectroscopic
methods. The FD+ mass spectrum shows only the
molecule peak, and the IR spectrum exhibits strong
bands at 1978 and 2135 cm-1, attributed to the CO and
CN stretching vibrations, respectively. The 31P NMR
spectrum consists of an AB2 spin system with the two
groups of signals separated by less than 1 ppm. The
identity of 10 is further established by the 13C NMR
data, which are also in accord with a structure similar
to those found for 4 and 9. Assuming the same preferred
orientation of the co-ligands as for 4 and 9, the vertical
mirror plane of the triphospholyl ligand would be
eliminated. To explain the NMR spectroscopic properties
of 10, the triphospholyl ligand is assumed to rotate free
within the NMR time scale.
lisonitrile at 70 °C, no triphosphacymantrene 3 is left
over. After chromatographic workup, the monosubsti-
tuted complex (η5-t-Bu2C2P3)(CN-Cy)(CO)2Mn (11) is
isolated in 52% yield as an orange to red liquid.
The FD+ mass spectrum of 11 shows only the mol-
ecule peak, and the solution IR spectrum exhibits one
absorption at 2118 cm-1, which can be attributed to the
isonitrile ligand, and two ν(CO) bands at 1968 and 1927
1
cm-1. The H NMR spectrum shows only one signal for
the tert-butyl groups. Likewise, the 31P NMR spectrum
of 11 supplies little information, as the nuclei are
isochronic, and only one sharp signal results. Due to the
proximity of the 31P signals, the 13C NMR signals of the
triphospholyl ligand represent the X-parts of AB2X spin
systems (A, B ) 31P, X ) 13C). As a result, each of the
signals exhibits an unsymmetric coupling pattern and
consists of eight lines.19 Due to the lack of information
from the 31P spectrum, no unambiguous ascertainment
of the coupling constants is possible.
Mech a n istic Asp ects. The reactivity of 3 and 4
toward CO ligand exchange is remarkably high, and this
is true for the photochemically and thermally initiated
reactions. To compare the triphospholyl complexes with
their parent cyclopentadienyl compounds, the cobalt and
manganese complexes have to be taken separately.
Ligand exchange reactions of cymantrene derivatives
do not occur under thermal conditions, and photochemi-
Even triphosphacymantrene 3 shows a remarkable
reactivity toward thermally initiated ligand exchange.
When it is reacted for 3 h with an excess of cyclohexy-
(19) Emsley, J . W.; Feeney, J .; Suthcliffe, L. H. High-Resolution
Nuclear Magnetic Resonance, 1st ed., 2nd impression; Pergamon
Press: Oxford: 1967; Vol. 1, pp 365-370.

2912 Organometallics, Vol. 20, No. 13, 2001
Heinemann et al.
Ta ble 7. Selected Bon d Len gth s (Å) a n d An gels
(d eg) for 8a a
Ta ble 9. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 9
Mn(1)-C(31)
Mn(1)-C(32)
Mn(2)-C(61)
Mn(2)-C(62)
Mn(1)-P(5)
Mn(2)-P(2)
C(31)-O(31)
C(32)-O(32)
C(61)-O(61)
C(62)-O(62)
P(2)-P(3)
1.789(6)
1.805(5)
1.801(6)
1.792(5)
2.2704(15)
2.2715(15)
1.154(6)
1.154(6)
1.157(6)
1.150(6)
2.1315(19)
2.1280(18)
1.755(5)
1.764(5)
1.755(5)
1.765(5)
1.758(5)
1.752(5)
1.778(5)
1.768(5)
Co-C(11)
Co-C(18)
P(1)-P(2)
P(2)-C(1)
P(3)-C(1)
P(3)-C(2)
P(1)-C(2)
C(11)-N(1)
C(18)-N(2)
1.814(3)
1.800(3)
2.1005(10)
1.785(3)
1.768(3)
1.763(3)
1.789(3)
1.164(3)
1.157(3)
C(11)-Co-C(18)
Co-C(11)-N(1)
Co-C(18)-N(2)
P(1)-C(2)-P(3)
C(2)-P(3)-C(1)
P(3)-C(1)-P(2)
C(1)-P(2)-P(1)
P(2)-P(1)-C(2)
90.61(11)
178.3(2)
178.6(3)
122.63(15)
97.00(12)
122.71(15)
98.70(9)
P(5)-P(6)
P(2)-C(2)
P(5)-C(4)
P(3)-C(1)
P(6)-C(5)
P(1)-C(1)
98.81(9)
P(4)-C(5)
P(1)-C(2)
Sch em e 4
P(4)-C(4)
Mn(1)-C(31)-O(31)
Mn(1)-C(32)-O(32)
P(2)-Mn(2)-C(62)
P(2)-Mn(2)-C(61)
C(31)-Mn(1)-C(32)
P(3)-P(2)-Mn(2)
C(2)-P(2)-Mn(2)
P(1)-C(1)-P(3)
178.9(5)
176.0(5)
90.03(16)
102.09(16)
89.3(2)
111.50(7)
138.64(17)
122.7(3)
96.93(18)
102.02(17)
118.3(3)
100.0(2)
C(1)-P(3)-P(2)
P(3)-P(2)-C(2)
P(2)-C(2)-P(1)
ligand or the deliberated free carbon monoxide20-22
(Scheme 4). In the case of short irradiation times,
monosubstituted complexes are isolated exclusively, but
after prolonged photolysis (g100 min) the primary
products react further and disubstituted complexes are
formed.23
CpCo(CO)2 follows a different mechanism. The CO
exchange is generally thermally initiated, and the
kinetics of the reaction are first-order according to both
the starting complex and the added ligand. An associa-
tive reaction pathway is thus assumed. The intermedi-
ate species CpCo(CO)2L avoids exceeding 18 VE by a
ring slippage of the Cp ligand, and the substitution
product is formed subsequently by the loss of one
carbonyl ligand. In most cases CpCo(CO)L complexes
are formed.24,25
As already outlined, the ligand exchange reactions of
3 and 4 are much more rapid than those of their parent
Cp complexes. When irradiated with a 125 W high-
pressure Hg vapor lamp in the presence of phosphanes,
the reactions of 3 and 4 are completed after 10-15 min.
As we are using Duran glassware, the UV part of the
lamp spectrum is absorbed. Under these conditions, the
cobalt complex 4 forms monosubstituted products, but
C(2)-P(1)-C(1)
a
The data of only half of the molecule are given. The second
half is almost isostructural. Further information is available in
the Supporting Information.
Ta ble 8. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 8ba
Mn(1)-C(31)
Mn(1)-C(32)
1.793(2)
1.804(2)
2.256(1)
1.150(3)
1.141(3)
2.121(1)
1.755(2)
1.766(2)
1.778(2)
1.756(2)
2.746(1)
3.440(1)
Mn(1)-P(2#1
C(31)-O(31)
C(32)-O(32)
P(2)-P(3)
)
P(2)-C(2)
P(3)-C(1)
P(1)-C(2)
P(1)-C(1)
P(2)-P(2#1
P(2)-P(3#1
)
)
Mn(1)-C(31)-O(31)
Mn(1)-C(32)-O(32)
C(31)-Mn(1)-C(32)
P(2#1)-Mn(1)-C(31)
P(2#1)-Mn(1)-C(32)
P(1)-C(1)-P(3)
176.8(2)
177.3(2)
87.41(10)
96.01(7)
94.65(7)
122.5 (11)
96.88(7)
102.2(7)
118.33(11)
99.87(9)
115.92(3)
134.01(7)
C(1)-P(3)-P(2)
P(3)-P(2)-C(2)
P(2)-C(2)-P(1)
C(2)-P(1)-C(1)
(20) Teixeira, G.; Avile´s, T.; Dias, A. R.; Pina, F. J . Organomet.
Chem. 1988, 353, 83-91.
(21) Herberhold, M.; Kremnitz, W.; Trampisch, H.; Hitam, R. B.;
West, A. J .; Taylor, D. J . J . Chem. Soc., Dalton Trans. 1982, 1261-
1273.
(22) Creaven, B. S.; Dixon, A. J .; Kelly, J . M.; Long, C.; Poliakoff,
M. Organometallics 1987, 6, 2600-2605.
(23) The reaction times for total conversions are between ca. 100
min ((η5-Cp′)(CO)3Mn with PPh3, 90 W medium-pressure Hg vapor
lamp)20 and ca. 5 h ((η5-Cp)(CO)3Mn with PEt3, 200 W medium-
pressure Hg vapor lamp).21
(24) Rerek, M. E.; Basalo, F. Organometallics 1982, 2, 372-376.
(25) For adequate reaction rates normally elevated temperatures
are needed. The ligand substitution reactions of (η5-Cp)(CO)2Co are
faster than those of Cp* derivatives, which can be explained by the
higher sterical demands of Cp*. In addition the cone angle of the
incoming ligand affects the reaction rates as well.24
P(3)-P(2)-Mn(1#1
C(2)-P(2)-Mn(1#1
)
)
a
Only the data of one of the two symmetrically independent
#
molecules are given.
indicates symmetry equivalent atoms.
Symmetry transformations used to generate equivalent atoms:
#1: -x+1, y+2, -z, #2: -x+1, -y+3, -z-1. Further information
is available in the Supporting Information.
cal activation is the method of choice. Concerning the
mechanism, the initial and rate-determining step is the
photochemical abstraction of one carbonyl ligand. The
resulting 16-VE intermediate immediately forms a
solvent complex, and the solvent is replaced again by a

Triphospholyl Metal Carbonyl Complexes
Organometallics, Vol. 20, No. 13, 2001 2913
triphosphacymantrene 3 yields the disubstituted com-
plex 7 selectively. Even after this short reaction time
there are no detectable traces of a manganese mono-
phosphane complex. Therefore, the reaction rate of 3
seems to be increased by several orders of magnitude
when compared with carbacyclic cymantrenes.23
It has to be stated that the enhancement of the
reaction rate does not depend directly on the number
of phosphorus atoms in the five-membered ring ligand.
Monophosphacymantrene derivatives, for example, are
less reactive than their carbacyclic analogues. If they
are irradiated in the presence of phosphanes, only
monosubstituted complexes are formed even after one
day reaction time. Only trimethyl phosphite allows the
formation of small amounts of the disubstituted prod-
uct.26
pyrrol ligand is slipped toward the nitrogen atom by
about 6 pm. This has been taken as evidence for a ring
slippage toward an η3-complexing mode of the ligand.30
For a diphospholyl ligand an η3-coordination has been
already observed,3 and in the case of iron as central
metal, coordinated phosphaallyl and diphosphaallyl
ligand substructures are regularly associated with small
valence electron counts.31 This should be in principle
possible for the neighboring element manganese as well.
The enhanced reactivity of cobalt complex 4 may be due
to an easier ring slippage as well. Unlike cymantrene,
cyclopentadienylcobalt dicarbonyl already reacts by an
associative mechanism;24 thus the lesser pronounced
differences between Cp(CO)2Co and its triphospha
analogue 4 can be explained with the same picture.
As a consequence, the difference in the photochemical
reactivity between cymantrene and triphosphacyman-
trene is unexpected. 3 exhibits only a slightly higher
absorbance in the UV-vis spectrum than cymantrene.
The absorbance coefficient ꢀ of 3 in n-hexane is 1700 L
mol-1 cm-1 (λmax ) 298 nm), and the corresponding
transition in cymantrene at 328 nm has a coefficient of
Con clu sion s
Triphospholylmetal carbonyl complexes such as 3 or
4 undergo effective carbonyl exchange reactions under
both photochemical and thermal conditions. If compared
with their carbacyclic counterparts, equivalent products
are formed photochemically, but the reaction times are
significantly shortened.
1150 L mol-1 cm-1 21
Therefore, the reactivity enhance-
.
ment of triphosphacymantrene 3 cannot be caused by
this effect. Additionally, the photolysis of carbacyclic
cymantrenes is very efficient, as the quantum yields are
about 0.8.20 We believe, therefore, that the photochemi-
cal reaction pathway is accompanied by a thermal one,
too. In agreement with this assumption 3 reacts at
slightly elevated temperatures such as 70 °C to form
the monoisonitrile complex 11 in a few hours. No such
reactions are known for cymantrene, but several unsuc-
cessful attempts have been reported.27 There is only one
exception, as Coville managed to react cymantrene at
high temperatures with isonitriles by utilizing PdO as
a catalyst, but long reactions times are required.28
The thermal reaction of (η5-t-Bu2C2P3)Co(CO)2 (4)
with cyclohexylisonitrile is accelerated as well. At room
temperature the disubstituted complex 9 is formed in
good yield, whereas only the monosubstituted derivative
of CpCo(CO)2 can be made this way. To replace both
CO ligands, the more reactive phenylisonitrile and
elevated temperatures are required.11
While for the cobalt complex 4 the reactivity is just
accelerated, triphosphacymantrene 3 exhibits a new
kind of reactivity. A thermally induced dissociative
pathway for 3 can be ruled out, as the CO stretching
frequencies of 3 and cymantrene are almost identical.5,29
On the other hand, the high reactivity of 3 may be
due to an associative reaction mechanism in combina-
tion with a ring slippage of the triphospholyl ring and
the formation of a manganese-coordinated phosphaallyl
or diphosphaallyl substructure.
Under thermal reaction conditions the reactions
proceed at much lower temperatures than observed for
cyclopentadienyl complexes. While cymantrene is inert
toward thermal carbonyl exchange, its triphospha ana-
logue 3 reacts under relatively mild conditions. This
behavior points to an additional reaction pathway. An
associative substitution mechanism in conjunction with
a ring slippage of the triphospholyl ligand is postulated.
Exp er im en ta l Section
Gen er a l Con sid er a tion s. All experiments were conducted
under nitrogen by using standard Schlenk and cannula
techniques. Solvents were dried according to described proce-
dures32 and used freshly distilled from the drying agent. NMR
solvents have been purchased from Sigma-Aldrich. [D8] toluene
and [D6] benzene were dried with potassium benzophenone,
distilled, and stored over molecular sieves. CDCl3 was degassed
and stored over molecular sieves. Cyclohexylisonitrile was
purchased from Fluka Chemie AG and used without further
purification. Triphenylphosphane was purchased from MERCK-
Schuchardt and was recrystallized from methylcyclohexane.
Dicobaltoctacarbonyl-, trimethyl-, and triethylphosphane have
been prepared using standard methods. Triphosphacyman-
trene (3) and 1-triorganylstannyl-3,5-di(tert-butyl)-1,2,4-triph-
osphole (2) were prepared as described before.5,12
(η5-t-Bu 2C2P 3)(CO)2Co (4). At 0 °C 1 g (2.92 mmol) of Co2-
(CO)8 in 40 mL of n-hexane is mixed with 1.63 g (2.8 mmol) of
(η1-t-Bu2C2P3)(SnPh3) (2) in 70 mL of n-hexane. The solution
is allowed to reach room temperature overnight. A 31P NMR
spectrum shows 4 as the only phosphorus-containing species.
The solution is concentrated in vacuo and distilled in a
Kugelrohr apparatus in an oilpump vacuum.(η5-t-Bu2C2P3)(CO)2-
Co (4) (0.189 g, 0.500 mmol, 19.5%) is obtained at 150 °C as a
red liquid, which solidifies at ca. -10 °C.
A similar mechanism has been stated by Basolo for
azacymantrene derivatives with a π-coordinated pyrrol
ligand, which undergo thermally initiated carbonyl
exchange reactions at 130 °C. In the solid state the
(30) J i, L.-N.; Kerschner, D. L.; Basalo, F. J . Organomet. Chem.
1985, 296, 83-94. Kerschner, D. L.; Basalo, F.; Rheingold, A. L.
Organometallics 1987, 6, 196-198.
(26) Breque, A.; Mathey, F. J . Organomet. Chem. 1978, 144, C9-
C11.
(27) Strohmeier, W.; Barbeau, C. Z. Naturforsch. B 1962, 17, 848-
849. Angelici, R. J .; Loewen, W. Inorg. Chem. 1967, 6, 682-686.
(28) Harris, G. W.; Boeyens, J . C. A.; Coville, N. J . J . Organomet.
Chem. 1983, 255, 87-94.
(29) Shen, L. M. C.; Long, G. G.; Moreland, C. G. J . Organomet.
Chem. 1966, 5, 362-369.
(31) Hu, D.; Scha¨ufele, H.; Pritzkow, H.; Zenneck, U. Angew. Chem.
1989, 101, 929-931. Driess, M.; Hu, D.; Scha¨ufele, H.; Pritzkow, H.;
Regitz, M.; Ro¨sch, W.; Zenneck, U. J . Organomet. Chem. 1987, 334,
C35-C38.
(32) Perrin, D. D.; Armarego, W. L. F. Purification of Laboratory
Chemicals, 3rd ed.; Butterworth-Heinemann: Oxford, 1988.

2914 Organometallics, Vol. 20, No. 13, 2001
Heinemann et al.
1
Sp ectr oscop ic Da ta for 4. H NMR (269.7 MHz, CDCl3,
-18 °C 115 mg (0.247 mmol, 73.6%) of (η5-t-Bu2C2P3)(CO)-
{P(CH3)3}2Mn (7) are obtained as red crystals.
rt): δ 1.37 (br, 18H, C(CH3)3). 31P{1H} NMR (161.7 MHz,
CDCl3, 20.4 °C): [AB2] spin system, δ 121.93 (t, J (31P,31P) )
2
1
Sp ectr oscop ic Da ta for 7. H NMR (399.65 MHz, CDCl3,
42 Hz, 1P, P(A)), 118.99 (d, 2J (31P,31P) ) 42 Hz, 2P, P(B)). 13C-
{1H} NMR (100.4 MHz, CDCl3, 26.4 °C): δ 200.46 (s, CO),
1
21.6 °C): δ 1.36 (s, CH3), 1.59 (s, CH3). H NMR (269.7 MHz,
[D8] toluene, -59.9 °C): δ 1.48-1.77 (m, 27H, P(CH3)3 and
C(CH3)3)), 1.94 (s, 9H, C(CH3)3)). 31P{1H} NMR (161.7 MHz,
[D8] toluene, -59.9 °C): [ABCDE] spin system, δ 22.6 (d,
167.08 (dpt, J (31P,13C) ) 81 Hz, Σ J (31P,13C) + J (31P,13C) )
1
1
2
104 Hz, Cring), 39.17 (dpt, J (31P,13C) ) 17 Hz, ∑2J (31P,13C) +
2
3J (31P,13C) ) 12 Hz, C(CH3)3), 36.05 (not res., C(CH3)3). IR (n-
hexane): ν(CO) 2035, 1990 cm-1. Mp: ca. -10 °C.
(η5-t-Bu 2C2P 3)(CO){P (CH2CH3)3}Co (5). At 0 °C 79 mg
(0.228 mmol) of (η5-t-Bu2C2P3)(CO)2Co (4) and 0.5 mL of
triethylphosphane (0.4 g, 3.4 mmol) in 80 mL of n-hexane are
irradiated in a Pyrex glass apparatus for 10 min with a 125
W high-pressure mercury lamp. The color changes to deep red.
The solution is filtered, the solvent removed in vacuo, and the
residue chromatographed on SiO2/5% H2O with n-hexane as
eluent. The main red fraction is collected to get 51 mg (0.117
mmol, 51.4%) of (η5-t-Bu2C2P3)(CO){P(CH2CH3)3}Co (5) as a
red oil.
2
2J (31P,31P) ) 59 Hz, 1P, P(CH3)3), 28.2 (d, J (31P,31P) ) 59 Hz,
1
2
1P, P(CH3)3), 33.0 (dd, J (31P,31P) ) 423 Hz, J (31P,31P) ) 42
Hz, 1P, Pring), 72.6 (dd, 2J (31P,31P) ) 42 Hz, 2J (31P,31P) ) 42
1
2
Hz, 1P, Pring), 85.3 (dd, J (31P,31P) ) 423 Hz, J (31P,31P) ) 42
Hz, 1P, Pring). 31P{1H} NMR (161.7 MHz, [D8] toluene, +90.0
°C): [AB2C2] spin system, δ 24.0 (s, 2P, P(CH3)3), 62 (br, 2P,
P
ring), 77.4 (t, 2J (31P,31P) ) 42 Hz, 1P, Pring). 13C{1H} NMR
(100.40 MHz, CDCl3, 22.6 °C): δ 25.1 (br, P(CH3)3), 36.1 (br,
C(CH3)3), 37.0 (br, C(CH3)3), 232 (s, CO). 13C{1H} NMR (100.40
MHz, [D8] toluene, 0.0 °C): δ 22.8 (br, P(CH3)3), 24.0 (br,
P(CH3)3), 34.9 (br, C(CH3)3), 35.7 (br, C(CH3)3) 230.5 (m, CO).
13C{1H} NMR (100.40 MHz, [D8] toluene, -59,9 °C): δ 23.8
(P(CH3)3), 25.5 (P(CH3)3), 36.2 (C(CH3)3), 36.6 (C(CH3)3), 36.9
(dd, 2J (13C,31P) ) 17.6 Hz, 2J (13C,31P) ) 17.6 Hz, C(CH3)3), 38.0
(dd, 2J (13C,31P) ) 16.6 Hz, 2J (13C,31P) ) 16.6 Hz, C(CH3)3), 144.8
(dd, 1J (13C,31P) ) 88.4 Hz, 1J (13C,31P) ) 70.8 Hz, Cring) 149.6
(dd, 1J (13C,31P) ) 90.4 Hz, 1J (13C,31P) ) 73.5 Hz, Cring) 232.5
(dd, 2J (13C,31P(PMe3)) ) 32 Hz, 2J (13C,31P(PMe3)) ) 32 Hz, CO).
Due to limited measurement time at low temperature, only
part of the P-C splittings are resolved in 13C NMR. IR (n-
hexane): ν(CO) 1863 cm-1. MS (FD+, n-hexane): m/z (%) 467
(100) [M]+. Anal. Calcd for (C17H36MnOP5): C 43.79, H 7.78.
Found: C 44.06, H 8.26. Mp: 132 °C.
1
Sp ectr oscop ic Da ta for 5. H NMR (269.7 MHz, CDCl3,
rt): δ 1.80 (dq, 2J (1H,31P) ) 8.8 Hz, 3J (1H,1H) ) 7.5 Hz, 6H,
CH2), 1.39 (s, 18H, C(CH3)), 1.10 (dt, 3J (1H,31P) ) 16.0 Hz,
3J (1H,1H) ) 7.5 Hz, 9H, CH3). 31P{1H} NMR (161.7 MHz,
CDCl3, 20.1 °C): [A2BX] spin system, δ 44.8 (br, 1P, PEt3),
81.1 (dt, J (31P,31P) ) 39.4 Hz, J (31P,31P) ) 8.6 Hz, 1P, Pring),
83.57 (d, 2J (31P,31P) ) 39.4 Hz, 2P, Pring). 13C{1H} NMR (67.83
MHz, CDCl3, rt): δ 204.0 (s, CO), 164.8 (ddpt, 1J (13C,31P) )
2
2
77.2 Hz, ∑1J (13C,31P) + J (13C,31P) ) 104.4 Hz, 2J (13C,31P) )
2
2.9 Hz, Cring), 38.5 (dpt, J (13C,31P) ) 18.0 Hz, ∑2J (13C,31P) +
2
3J (13C,31P) ) 11.6 Hz, C(CH3)3), 36.6 (dpt, J (13C,31P) ) 8 Hz,
3
∑3J (13C,31P) + 4J (13C,31P) ) 8 Hz, C(CH3)3), 23.7 (d, 1J (13C,31P)
) 29 Hz, CH2), 8.3 (s, CH3). IR (n-hexane): ν(CO) 1941 cm-1
MS (FD+, n-hexane): m/z (%) 436 (100) [M]+.
.
{µ[1:1-5-η-t-Bu 2C2P 3](CO)2Mn }2 (8a a n d 8b). A 159 mg
(0.430 mmol) sample of (η5-t-Bu2C2P3)(CO)3Mn (3) in 180 mL
of n-hexane is irradiated in a Pyrex glass apparatus at 0 °C
for 10 min with a 125 W high-pressure mercury lamp. The
solution is filtered, and the solvent is removed in vacuo. The
(η5-t-Bu 2C2P 3)(CO){P (C6H5)3}Co (6). At -15 °C 72 mg
(0.208 mmol) of (η5-t-Bu2C2P3)(CO)2Co (4) and 260 mg (0.99
mmol) of triphenylphosphane in 120 mL of n-hexane are
irradiated in a Pyrex glass apparatus for 15 min with a 125
W high-pressure mercury lamp. The color changes to bordeaux
red. The solution is filtered, the solvent removed in vacuo, and
the residue chromatographed on SiO2/5% H2O with a 4:1
mixture of n-hexane and toluene as eluent. The main bordeaux
red fraction is collected, and the solvents are removed in vacuo
again. The product is recrystallized from n-hexane at 4 °C to
yield 83 mg (0.143 mmol, 69%) of (η5-t-Bu2C2P3)(CO){P(C6H5)3}-
Co (6) as deep red crystals.
residue is chromatographed on SiO2/5% H2O with
a 1:1
mixture of n-hexane and toluene as eluent to get a deep red
fraction. The solvent is removed in vacuo, and the orange-red
solid is recrystallized from n-hexane at -18 °C to yield 88 mg
(0.128 mmol, 60%) of a mixture of the rac and meso complexes
{µ[1:1-5-η-t-Bu2C2P3](CO)2Mn}2 (8a and 8b) as a red micro-
crystalline solid.
Sp ectr oscop ic Da ta for a n Ap p r oxim a tely 1:2 Mixtu r e
1
of 8a a n d 8b. H NMR (269.7 MHz, CDCl3, rt): 8a : δ 1.41 (s,
1
Sp ectr oscop ic Da ta for 6. H NMR (269.7 MHz, CDCl3,
18H, CH3), 1.23 (s, 18H, CH3); 8b: 1.61 (s, 18H, CH3), 1.24 (s,
18H, CH3). 31P{1H} NMR (161.70 MHz, CDCl3, 23 °C): 8a :
[AA′XX′YY′] spin system, δ 95.64 (m, 2P, P(A)), ∼78 (m, 2P,
P(X)), 61.73 (m, 2P, P(Y)); 8b: [ABC]2 spin system, δ 77.46
(br, dd, 1J (31P,31P) ) 424.5 Hz, 2J (31P,31P) ) 42.1 Hz, 2P, P(A)),
rt): δ 1.40 (s, 18H, CH3), 7.37 (m, 9H, o- and p-Ph-H), 7.61 (m,
6H, m-Ph-H). 31P{1H} NMR (161.7 MHz, CDCl3, 24.9 °C): [A2-
BX] spin system, δ 57.1 (br, 1P, P(C5H6)3), 75.8 (dt, 2J (31P,31P)
) 10.8 Hz, J (31P,31P) ) 36.2 Hz, 1P, Pring), 97.2 (d, J (31P,31P)
2
2
) 36.2 Hz, 2P, Pring). 13C{1H} NMR (67.83 MHz, CDCl3, rt): δ
1
2
79.98 (dd, J (31P(2),31P(3)) ) 424.5 Hz, J (31P,31P) ) 38.8 Hz,
36.61 (dpt, 3J (31P,13C) ) 8.8 Hz, ∑3J (31P,13C) + J (31P,13C) )
4
2P, P(B)), 72.96 (dd, J (31P,31P) ) 42.1 Hz, J (31P,31P) ) 38.8
2
2
8.8 Hz, CH3), 39.00 (dpt, J (31P,13C) ) 18.0 Hz, ∑2J (31P,13C) +
2
Hz, 2P, P(C)). IR (n-hexane): ν(CO) 1962, 1930 cm-1. MS (FD+,
3J (31P,13C) ) 11.6 Hz, C(CH3)3), 127.89 (d, 3J (31P,13C) ) 10.4
n-hexane): m/z (%) 685 (100) [M]+. Anal. Calcd for (C24H36
-
Hz, m-Ph-C), 129.99 (d, J (31P,13C) ) 2.6 Hz, p-Ph-C), 134.00
4
Mn2O4P6): C 42.13, H 5.30. Found: C 42.27, 5.61.
(d, 2J (31P,13C) ) 10.9 Hz, o-Ph-C), 137.03 (d, 1J (31P,13C) ) 46.11
Hz, i-Ph-C), 166.32 (ddpt, 2J (31P(PPh3),13C) ) 3.3 Hz, 1J (31P,13C)
) 76.3 Hz, ∑1J (31P,13C) + 2J (31P,13C) ) 104.2 Hz, Cring), 203 (s,
CO). IR (n-hexane): ν(CO) 1953 cm-1. MS (FD+, CH2Cl2): m/z
(%) 580 (100) [M]+. Anal. Calcd for (C29H33CoOP4): C 60.01,
H 5.73. Found: C 60.10, H 6.04. Mp: 151 °C.
(η5-t-Bu 2C2P 3)(CNCy)2Co (9) a n d (η5-t-Bu 2C2P 3)(CO)-
(CNCy)Co (10). At -60 °C 0.072 g (0.208 mmol) of (η5-t-
Bu2C2P3)(CO)2Co (4) in 20 mL of n-hexane is reacted with 6
mL of a cyclohexylisonitrile solution (0.045 g, 0.41 mmol
isonitrile in THF/n-hexane). The solution is allowed to warm
to room temperature and is stirred for an additional 1.5 h.
The solvent and all volatile substances are removed in vacuo.
The residue is redissolved in n-hexane and filtered to get an
orange-red solution, part of the solvent is removed in vacuo,
and the resulting solution is chromatographed on SiO2/5% H2O
with a 3:1 mixture of n-hexane and toluene as eluent. Two
fractions are collected. The first orange one gives 8 mg (0.019
mmol, 9%) of (η5-t-Bu2C2P3)(CNCy)(CO)Co (10) as a red oil.
The second fraction results in a orange-brown solid, which is
recrystallized from n-hexane at -18 °C to yield 81 mg (0.159
(η5-t-Bu 2C2P 3)(CO){P (CH3)3}2Mn (7). A 0.124 g (0.335
mmol) sample of (η5-t-Bu2C2P3)(CO)3Mn (3) and 4 mL (2.95 g,
38.8 mmol) of trimethylphosphane are irradiated in 60 mL of
n-hexane in a Pyrex glass apparatus at -20 °C for 15 min with
a 125 W high-pressure mercury lamp. The color changes from
bright yellow to orange-red. All volatile substances are re-
moved in vacuo, and the orange residue is chromatographed
on SiO2/5% H2O with a 5:2 mixture of n-hexane and toluene.
The main orange-red fraction is collected, and the solvent is
removed in vacuo again. By crystallization from n-hexane at

Triphospholyl Metal Carbonyl Complexes
Organometallics, Vol. 20, No. 13, 2001 2915
mmol, 77%) of (η5-t-Bu2C2P3)(CNCy)2Co (9) as dark red needles
and brownish yellow plates.
of an AB2X spectrum (A, B ) 31P, X ) 13C), C(CH3)3), 36.85 (s,
Cy (â-C)), 27.93 (s, Cy (γ-C)), 26.04 (s, Cy (δ-C)). IR (n-
hexane): ν(CN) 2118, ν(CO) 1968, 1927 cm-1. MS (FD+,
n-hexane): m/z (%) 451 (100) [M]+.
Sp ectr oscop ic Da ta for 9. 1H NMR (399.65 MHz, C6D6,
22.3 °C): δ 3.18 (m, 2H, R-Cy-H), 1.75 (s, 18H, CH3), ∼1.5 (m,
8H, Cy-H), ∼1.4 (m, 4H, Cy-H), ∼1.1 (m, 4H, Cy-H), ∼1.0 (m,
4H, Cy-H). 31P{1H} NMR (161.7 MHz, C6D6, 22.6 °C): [A2B]
spin system, δ 97.79 (d, 2J (31P,31P) ) 47.7 Hz, 2P, P(A)), 103.66
(t, 2J (31P,31P) ) 47.4 Hz, 1P, P(B)). 13C{1H} NMR (100.4 MHz,
C6D6, 21.8 °C): δ 158.54 (s, CN), 149.08 (dpt, 1J (31P,13C) ) 76.9
Cr ysta l Str u ctu r e Deter m in a tion of 9. Crystal data were
collected on a Bruker AXS SMART 1000 diffractometer with
CCD area detector (Mo KR radiation, graphite monochromator,
λ ) 0.71073 Å) using the SMART software.33 The reflection
intensities were integrated using SAINT33 and corrected for
absorption using SADABS.34 The structures were solved by
direct methods and refined by full-matrix least-squares pro-
cedures against F2 with all reflections using SHELXTL-
programs.35 All non-hydrogen atoms were refined anisotropi-
cally. All hydrogen atoms were located in difference Fourier
maps and refined isotropically. Crystal data and experimental
details are listed in Table 4.
Cr ysta l Str u ctu r e Deter m in a tion s of 4, 6, 7, 8a , a n d
8b. Data were collected on a Siemens P4 (4, 7, 8a , 8b) or a
Nicolet R3m/V diffractometer (6) using Mo KR radiation (λ )
0.71073 Å, graphite monochromator). Reflection intensities
were corrected for Lorentz and polarization effects. An absorp-
tion correction has been applied using ψ-scans (4, 7, 8a , 8b),35
while for 6 absorption effects have been neglected. The
structures were solved by direct methods and refined by full-
matrix least-squares procedures against F2 with all reflections
using SHELXTL NT 5.1.35 All non-hydrogen atoms were
refined anisotropically. The hydrogen atoms were located in
difference Fourier maps and refined with a fixed common
isotropic displacement parameter. Crystal data and experi-
mental details are listed in Tables 1, 4, and 6.
2
Hz, ∑1J (31P,13C) + J (31P,13C) ) 100.8 Hz, Cring), 54.75 (s, Cy-
(R-C)), 39.07 (dpt, 2J (31P,13C) ) 18.2 Hz, ∑2J (31P,13C) +
3J (31P,13C) ) 13.2 Hz, C(CH3)3), 36.39 (not res., C(CH3)3), 33.22
(s, Cy (â- or γ- or δ-C)), 25.38 (s, Cy (â- or γ- or δ-C)), 23.29 (s,
Cy (â- or γ- or δ-C)). IR (n-hexane): ν(CN) 2120 cm-1. MS (FD+,
CH2Cl2): m/z (%) 508 (100) [M]+. Anal. Calcd for (C24H40
-
CoN2P3): C 56.70, N 5.51, H 7.93. Found: C 57.09, N 5.36, H
8.24. Mp: decomposition without melting at ca. 120 °C.
Sp ectr oscop ic Da ta for 10. 1H NMR (269.7 MHz, C6D6,
rt): δ 2.72 (m, 1H, R-Cy-H), 1.46 (s, 18H, CH3), 0.6-1.4 (m,
10H, Cy-H). 31P{1H} NMR (161.7 MHz, C6D6, 26.2 °C): [AB2]
spin system, δ 112.38 (t, 2J (31P,31P) ) 45.8 Hz, 1P, P(A)), 111.58
(d, 2J (31P,31P) ) 45.8 Hz, 2P, P(B)); the chemical shifts and
coupling constants have been obtained by using the analytic
solution for an [AB2] spin system. 13C{1H} NMR (100.4 MHz,
C6D6, 25.0 °C): δ 158.29 (dpt, 1J (31P,13C) ) 88.8 Hz, ∑1J (31P,13C)
+ 2J (31P,13C) ) 118.4 Hz, Cring), 54.95 (s, Cy (R-C)), 39.01 (dpt,
2J (31P,13C) ) 17.0 Hz, ∑2J (31P,13C) + 3J (31P,13C) ) 13.6 Hz,
C(CH3)3), 36.06 (not res., C(CH3)3), 32.38 (s, Cy (â- or γ- or
δ-C)), 24.76 (s, Cy (â- or γ- or δ-C)), 22.92 (s, Cy (â- or γ- or
δ-C)); due to the small amounts of 10, the signals of the
isonitrile and carbonyl C atoms could not be detected. IR (n-
hexane): ν(CO) 1978 cm-1, ν(CN) 2135 cm-1. MS (FD+,
n-hexane): m/z (%) 427 (100) [M]+.
Ack n ow led gm en t. This work was supported by the
Deutsche Forschungsgemeinschaft and the Fonds der
Chemischen Industrie. M.Z. is grateful for a scholarship
by the DFG-Graduiertenkolleg Phosphorchemie als
Bindeglied verschiedener chemischer Disziplinen, at the
University of Kaiserslautern, Germany. We also thank
Dr. M. Moll for the measurement of variable-tempera-
ture NMR spectra.
(η5-t-Bu 2C2P 3)(CNCy)(CO)2Mn (11). A 108 mg (0.292
mmol) sample of (η5-tBu2C2P3)(CO)3Mn (3) and 1 mL of
cyclohexylisonitrile (0.88 g, 8.06 mmol) in 80 mL of n-hexane
are refluxed for 3 h. The bright yellow color changes to orange.
According to IR control, no (η5-t-Bu2C2P3)(CO)3Mn (3) is left
over. The solution is allowed to cool to room temperature, all
volatile substances are removed in vacuo, and the residue is
chromatographed on SiO2/5% H2O with n-hexane as eluent.
The first fraction is collected to yield 69 mg (0.153 mmol,
52.4%) of (η5-tBu2C2P3)(CO)2(CN-Cy)Mn (11) as an orange to
red liquid.
Su p p or tin g In for m a tion Ava ila ble: Further details of
the structure determination including tables of atomic coor-
dinates, bond distances and angles, and thermal parameters.
This material is available free of charge via the Internet at
http://pubs.acs.org.
1
Sp ectr oscop ic Da ta for 11. H NMR (399.65 MHz, C6D6,
21.3 °C): δ 2.87 (m, 1H, R-Cy-H), 1.36 (s, 18H, CH3), 0.5-1.4
(m, 10H, Cy-H). 31P{1H} NMR (161.7 MHz, C6D6, 22.5 °C):
[AB2] spin system, δ 103.64 (m, 3P). 13C{1H} NMR (100.40
MHz, [D8] toluene, rt): δ 169.5 (s, CN), 157.06, 156.32, 156.12,
156.12, 155.51, 155.17, 154.44 (each s, X-part of an AB2X
spectrum (A, B ) 31P, X ) 13C), Cring), 58.07 (s, Cy (R-C)), 38.91,
38.82, 38.78, 38.69, 38.64, 38.64, 38.55, 38.46 (each s, X-part
of an AB2X spectrum (A, B ) 31P, X ) 13C), C(CH3)3), 36.57,
36.50, 36.50, 36.45, 36.42, 36.42, 36.38, 36.32 (each s, X-part
OM001068Q
(33) SMART and SAINT, NT V5.0, Area detector control and
integration software; Bruker AXS: Madison, WI, 1999.
(34) Sheldrick, G. M. SADABS, Program for scaling and correction
of area detector data; Go¨ttingen, Germany, 1996.
(35) Sheldrick, G. M. SHELXTL NT V5.1, Bruker AXS: Madison,
WI, 1999.