Protonation of manganese phosphonioallenyl complexes

Article abstract of DOI:10.1016/j.jorganchem.2011.07.034

The addition of phosphines to the manganese allenylidene complexes Cp(CO)₂MnCCC(Ph)R (R = H, Ph) proceeds selectively at the C _α atom to result in the α-phosphonioallenyl complexes Cp(CO)₂Mn^--C(⁺PR₃ ¹)CC(Ph)R. The protonation of the latter affords the η²-(1,2)-phosphonioallenes Cp(CO)₂Mn{η ²-(1,2)-HC(⁺PR₃¹)CC(Ph)R}, rather than the phosphoniovinylcarbenes Cp(CO)₂MnC(⁺PR ₃¹)-HCC(Ph)R. All complexes obtained are stereochemically rigid and do not isomerize into the η²-(2,3)-phosphonioallene isomers.

Full text of DOI:10.1016/j.jorganchem.2011.07.034

Journal of Organometallic Chemistry 696 (2011) 3408e3414
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Protonation of manganese phosphonioallenyl complexes
*
Kamil I. Utegenov, Vasily V. Krivykh, Ivan V. Glukhov, Pavel V. Petrovskii, Nikolay A. Ustynyuk
A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 ul. Vavilova, 119991 Moscow, Russian Federation
a r t i c l e i n f o
a b s t r a c t
Article history:
The addition of phosphines to the manganese allenylidene complexes Cp(CO)2Mn]C]C]C(Ph)R
(R ¼ H, Ph) proceeds selectively at the Ca atom to result in the -phosphonioallenyl complexes
Cp(CO)2MnꢀeC(þPR13)]C]C(Ph)R. The protonation of the latter affords the 2-(1,2)-phosphonioallenes
Cp(CO)2Mn{
2-(1,2)-HC(þPR13)]C]C(Ph)R}, rather than the phosphoniovinylcarbenes Cp(CO)2Mn]
C(þPR13)eHC]C(Ph)R. All complexes obtained are stereochemically rigid and do not isomerize into the
2-(2,3)-phosphonioallene isomers.
Received 22 June 2011
Received in revised form
21 July 2011
a
h
h
Accepted 25 July 2011
h
Keywords:
Ó 2011 Elsevier B.V. All rights reserved.
Allenylidene complexes
Nucleophilic addition
Phosphonioallenyl complexes
Protonation
Phosphonioallene complexes
1. Introduction
Despite the formation of the zwitter-ionic Ca adducts
[M]ꢀeC(þL)]C]CR2 and Cg adducts [M]ꢀeC^CeCR2(þL) (L ¼ PR3,
NR3, and SR2) determines the course of many reactions of allenyli-
dene complexes, the reactions of these adducts remain virtually
unexplored and deserve careful study. We started a systematic study
of the reactions of the adducts of phosphorus nucleophiles with
vinylidene and allenylidene complexes [5]. In particular, the
protonation of manganese and rhenium phosphoniovinyl complexes
A was found to proceed at the metal atom via the intermediate
hydride B and affords phosphonioalkenes C, rather than phospho-
niocarbenes D [5b] (Scheme 1).
Transition metal allenylidene complexes [M]]Ca]Cb]CgR2
attract attention as efficient building blocks for the selective
carboneheteroatom and carbonecarbon bond formation [1] and
as alkene metathesis catalyst precursors [2]. Thanks to the pres-
ence of the electrophilic (Ca and Cg) and nucleophilic (Cb) sites,
these compounds can react with both nucleophiles and electro-
philes, but their rich reactivity is primarily related to their reac-
tions with nucleophiles. Protic nucleophiles, such as secondary
amines and phosphines, alcohols, and thiols, add to allenylidene
complexes at the Ca]Cb bond [1]. The analogous reactions
involving protic N,N- and N,S-dinucleophiles are accompanied by
cyclization to form the unusual heterocycles, wherein one of the
carbon atoms is linked to the transition metal via the ordinary or
double metalecarbon bond [1]. The addition of tertiary phos-
phines to allenylidene complexes proceeds reversibly at the Ca or
In order to determine the generality of the reactions shown in
Scheme 1, in the present work we studied the protonation of the
manganese zwitter-ionic
MneC(þPR13)]C]C(Ph)R and found that these reactions also
afforded the
2-(1,2)-phosphonioallenes Cp(CO)2Mn( 2-H(R13Pþ))
C]C]CPhR, rather than the (phosphonio)vinylcarbenes Cp(CO)2
Mn]C(þPR13)CH]C(Ph)R. Previously, the manganese
-phospho-
a-phosphonioallenyl complexes Cp(CO)2
h
h
Cg atoms to afford the
a
-phosphonioallenyl [M]ꢀeC(þPR3)]C]
a
CR2 [3aef] or
g
-phosphonioalkynyl [M]ꢀeC^CeCR2(þPR3) [3hej]
nioallenyl adducts of the type Cp(CO)2MneC(PPh3)]C]CR2
(R ¼ Ph, t-Bu) [3c] have been synthesized for only one phosphine
(PPh3), one adduct (R ¼ Ph) having been characterized by X-ray
diffraction. However, their protonation has not been studied.
adducts, respectively, and, in some cases, a mixture of both
adducts [3h]. There are also reports on the initial phosphine
attack at the Cg atom followed by the rearrangement into the a-
phosphonioallenyl adducts [4]. Whether the reaction proceeds at
the Ca or Cg atom is defined by a delicate balance of various
factors, such as the nature of the metal atom, electronic and steric
properties of ancillary ligands and substituents at the Cg atom of
the allenylidene ligand.
2. Results and discussion
2.1. Manganese 1-phosphonio-3,3-diphenylallenyl complexes
The reactions of complex 1 with tertiary phosphines (PPh2Me
(a), PPhMe2 (b), and PMe3 (c)) proceed at the Ca atom to result in
the zwitter-ionic adducts 2aec (Scheme 2).
* Tel.: þ7 (499) 135 50 64; fax: þ7 (499) 135 50 85.
E-mail address: ustynyuk@ineos.ac.ru (N.A. Ustynyuk).
0022-328X/$ e see front matter Ó 2011 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2011.07.034

K.I. Utegenov et al. / Journal of Organometallic Chemistry 696 (2011) 3408e3414
3409
H
H
Ph
Ph
H
Ph
HBF4/Et2O
-70 o
CH2Ph
C
Ph
C
Ph
~H
20 o
[M]
H
[M]
C
[M]
HBF4/Et2O
CH2Cl2, - 70oC
C
C
H
2a-c
PR3 BF4
C
C
PR3
A
PR3 BF4
Mn
C
OC
OC
BF4
PR3
B
[Mn]
H
BF4
PR3
D
PR3= PPh2Me, 4a (74%), PPhMe2, 4b (68%), PMe3 4c (59%)
[M] = (
η
5-C5H5)(CO)2Mn, (
η
5-C5H5)(CO)2Re
Ph
Ph
Ph
Ph
Scheme 1.
C
C
C
C
BF4
C
C
PPh2
HBF4/Et2O
CH2Cl2, - 70oC
BF4
Mn
Mn
OC
OC
Contrary to our expectations, the reaction products of complex 1
with diphosphines dppm and dppe were different: the mono-
nuclear adduct 2d formed in the reaction with dppm, while the
reaction with dppe afforded the binuclear adduct 3 even if the
reagent ratio was 1:1.
3
CO
CO
CH2 CH2
PPh2
H
H
5 (57%)
Scheme 3.
The spectral characteristics of complexes 2 and 3 agree quite
well with their structure. Their IR spectra contain two carbonyl
bands (nCO 1894, 1824 cmꢀ1), which are very close to those
observed earlier for the analogous phosphonioallenyl complex
the structures of the products were confirmed by 1H and 31P NMR
spectroscopy and, in some cases, by 13C NMR spectroscopy.
Unlike the reactions shown in Scheme 3, the protonation of the
dppm adduct 2d afforded exclusively the phospine complex 6
containing the allenylphosphonium fragment in the side chain
Cp(CO)2MꢀeC(þPPh3)]C]CPh2 [3c] and
phosphoniovinyl
complexes Cp(CO)2MꢀeC(þPR3)]C(H)Ph [5b] and expectedly
shifted to low frequencies compared to those of 1 (nCO 1994,
1940 cmꢀ1). The signals for the cyclopentadienyl protons appear in
(Scheme 4). We failed to detect the intermediate
h
2-phospho-
the region of
d 4.2e4.5; the methyl protons of phosphorus bonded
nioallene complex of type 4.
methyl groups in 2a,c are clearly seen as doublets at
d 1.93
We assume that the initially formed
h
2-allene complex
(2JPH ¼ 8.3 Hz) and 0.92, (2JPH ¼ 11.3 Hz), respectively, while the
undergoes intramolecular substitution of the free phosphine frag-
ment of dppm for the allene ligand, which is presumably promoted
by an easy accessibility of the chelate five-membered ring in the
transition state. The structure of complex 6 was proposed based on
the IR, 1H, and 31P NMR spectral data and finally confirmed by X-ray
diffraction (Fig. 1).
signal for the methyl protons in 2b appears as a broad singlet at
d
d
1.42. The phenyl protons appear as multiplets in the region of
6.9e7.5. The 31P{1H} NMR spectra of 2 and 3 contain the signals
for the phosphonium nucleus in the narrow region of
d 12.5e18.0
typical of the previously reported phosphonioallenyl [3c] and
phosphoniovinyl complexes [5b].
2.3. Manganese 1-phosphonio-3-phenylallenyl complex and
protonation thereof
2.2. Protonation of the manganese 1-phosphonio-3,3-
diphenylallenyl complexes
We tried to extend these reactions to adduct 8 formed by the
additionofmethyldiphenylphosphinetothemonophenylallenylidene
complex 7 (Scheme 5). Complex 7 was found to be unstable and
decomposed on attempting to isolate it [6]. Therefore, the desired
adduct 8 was prepared by the addition of phosphine to complex 7
generated in situ (see Scheme 5).
The acid treatment of 8 under the same conditions as for 2
resulted in the corresponding phosphonioallene 9 (Scheme 6).
The structure of 9 was established by X-ray diffraction (Fig. 2).
As stated above (see Scheme 1), the protonation of manganese
and rhenium phosphoniovinyl complexes Cp(CO)2MꢀeC(þPR3)]
C(H)Ph (M ¼ Mn, Re) proceeds at the metal atom to form the
phosphonioalkene complexes, rather than the phosphoniocarbene
ones. We showed that the protonation of the phosphonioallenyl
complexes 2aec and 3 proceeded similarly to result in the phos-
phonioallenes, rather than the (phosphonio)vinylcarbenes (Scheme
3). The course of the reaction was monitored by IR spectroscopy and
2.4. Isomerism of phosphonioallene complexes
Ph
Ph
PR3
hexane
Mn C C C
Ph
Ph
Mn
OC
OC
OC
OC
Thus, the protonation of the manganese
complexes Cp(CO)2MnꢀeC(þPR13)]C]C(Ph)R affords the
phosphonioallenes [(
5-C5H5)(CO)2Mn( 2-HC(þPR13)]C]CHPh)]
a
-phosphonioallenyl
C C C
h
2-1,2-
R3P
1
h
h
R3P = Ph2MeP, 2a (79%), PhMe2P, 2b (97%),
PMe3, 2c (63%), dppm, 2d (73%)
BF4, which allows one to assume proceeding of the reaction along
the same pathway as for the protonation of the structurally close
phosphoniovinyl adducts Cp(CO)2MnꢀeC(þPR3)]C(H)Ph (Scheme
1) [5b], i.e., through the proton addition to the metal atom followed
by the C,H-reductive elimination in the intermediate hydrides
Cp(CO)2(H)MneC(þPR13)]C]C(Ph)R. It is very likely that the
dppe
hexane
Ph
C C C
Ph
Mn
OC
OC
Ph2P
H2C CH2
PPh2
Ph
Ph
protonation of the zwitter-ionic
other transition metals will occur in the same way to result in the
corresponding
2-1,2-phosphonioallenyl structures as the primary
reaction products. Similarly, the protonation of the -phospho-
nioallenyl compounds should afford the corresponding
2-2,3-
phosphonioallene complexes. This is in good accordance with the
a-phosphonioallenyl complexes of
CO
CO
C C C
Mn
h
g
3 (96%)
h
Scheme 2.

3410
K.I. Utegenov et al. / Journal of Organometallic Chemistry 696 (2011) 3408e3414
Ph
Ph
H
Ph
Ph
C
C
C
C
C
Ph
Ph
HBF4/Et2O
Mn
Mn
OC
OC
OC
OC
CH2
Mn PPh2
C
CH2
C
C
C
CH2Cl2, - 70oC
H
PPh2
OC
OC
PPh2
PPh2CH2PPh2
PPh2
BF4
BF4
2d
6 (89%)
Scheme 4.
protonation of the rhenium
Cp(CO)2ReeC(Tol)]C]C(Ph)PPh2Me with TfOD, which was
reported to give Cp(CO)2Re{
2-(2,3)-DC(Tol)]C]C(Ph)PPh2Me}
(10) [7]. It should be noted that the
2-(1,2)-phosphonioallene
g
-phosphonio-
a
-tolylallenyl complex
chromium and molybdenum arenetricarbonyl complexes, the
h
2-2,3-
phosphonioallene complexes (h h
6-C6H6ꢀnMen)(CO)2M( 2-2,3-H2C]
h
C]C(þPPh3)H]BF4 (M ¼ Cr, n ¼ 3,5; M ¼ Mo, n ¼ 5, 6) formed first and
h
then isomerized slowly into the corresponding h
2-1,2 isomers of type
complexes are known only by solitary examples [8].
E [8a,b] at room temperature in CD2Cl2 or CD3NO2. Besides the above-
mentioned rhenium
2-(2,3)-phosphonioallene complex [7], the
ruthenium
2-(2,3)-phosphonioallene complex [Ru( 2-H2C]C]
CHPPh3)(CO)2(PPh3)2]Br has been prepared recently by the reaction
of Ru(CO)2(PPh3)3 with [HC^CCH2PPh3]Br [12].
The transition metal monosubstituted allene complexes can
h
exist as three isomers, namely,
h
2-(1,2)-isomer (E) and syn- and
h
h
anti-
h
2-(2,3)-isomers (F and G, respectively) (Chart 1). For example,
the cationic iron methylallene complex exists as a mixture of
isomers F and G ([M] ¼ [Cp(CO)2Fe]þ, R ¼ Me) as identified by NMR
spectroscopy [9], while the manganese methoxyallene and
hydroxamethylallene complexes exist as a mixture of all three
possible isomers ([M] ¼ Cp(CO)2Mn, R ¼ OMe and CH2OH) [10].
Almost all known transition metal complexes with the unsym-
metrically substituted allenes represent one isomer [11], which is
On keeping in solutions (acetone, dichloromethane) at room
temperature, the manganese complexes 4aec, 5, and 9 do not
undergo the h2
,h
2-haptotropic rearrangement into the corre-
sponding
h
2-(2,3)-phosphonioallene isomers. The similar structural
rigidity has been noted earlier for all three possible isomers of the
manganese methoxyallene and hydroxymethylallene complexes
[10]. As mentioned above, the structurally similar chromium and
usually the anti-
substituents or the
h
2-(2,3)-isomer G in the case of donor (methyl)
h
2-(1,2)-isomer E in the case of acceptor
molybdenum complexes (h h
6-C6H6ꢀnMen)(CO)2M( 2-2,3-H2C]C]
substituents. As mentioned above, all manganese phosphonioallene
complexes (4aec, 5, and 9) obtained in this work are the
isomers of type E.
C(þPPh3)H)]BF4 (M ¼ Cr, n ¼ 3, 5; M ¼ Mo, n ¼ 5, 6) isomerize slowly
h
2-(1,2)-
into the corresponding h
2-1,2 isomers of the type E [8a,b] at room
temperature in CD2Cl2. It follows from these data that the ability of
Among the synthetic approaches to the alternative
h
2-(2,3)-
h
2-phosphonioallene complexes to undergo the haptotropic isom-
isomers, we would like to point out first of all the photochemical
erization depends largely on the metal nature [13]. Presumably, this
is due to a lower kinetic barrier for the rearrangement of chromium
and molybdenum complexes as compared with the analogous
complexes of manganese and other metals.
reaction of the transition metal half-sandwich carbonyls with prop-
argyl alcohol followed by the treatment of the in situ generated h2
-
alkyne complexes with triphenylphosphine and tetrafluoroboric acid
[8]. In thecaseofcymantrene, [Cp(CO)2Mn(
2-2,3-H2C]C]C(þPPh3)
H)]BF4 10 was obtained as the only product [8a], while, in the case of
h
2.5. Molecular structures of (
h
5-C5H5)(CO)2MnePPh2CH2(þPPh2
5-C5H5)(CO)2Mn( 2-HC(þPPh2Me)]C]
C(H)]C]CPh2) (6) and [(
C(H)Ph)]BF4 (9)
h
h
The molecular geometries of 6 and 9 are shown in Figs. 1 and 2,
respectively. Complex 6 is the first structurally characterized
compound, wherein the phosphonioallene fragment is remote from
the metal atom. The double-bond distances C(33)eC(34) of
ꢀ
1.307(3) and C(34)eC(35) of 1.314(3) A in the allene moiety of 6 are
ꢀ
comparable to those in the free allene molecule (1.308 A) [14] and
those in Cp(CO)2MneC(PPh3)]C]CPh2 [3c] (1.303(3) and 1.328
ꢀ
(3) A, respectively). The allene carbon atoms in 6 deviate slightly
from linearity (the angle C(33)eC(34)eC(35) is 172.2(3)ꢁ).
The allene moiety of 9 is bonded to the manganese atom of the
Cp(CO)2Mn fragment through C(8) and C(9). The MneC distance to
Ph
H
1) BCl3, hexane, -78 o
2) Et3N, hexane
C
Ph
C
C
Mn
C
H
OC
OC
C
C
Mn
C
OC
OC
H
OEt
in situ
7
PPh2Me
hexane
Fig. 1. Molecular structure of [(h
5-C5H5)(CO)2MnePPh2CH2(þPPh2CH]C]CPh2)]BFꢀ4
Mn
Ph
H
OC
OC
(6) (50% probability displacement thermal ellipsoids). BFꢀ4 anion is omitted for clarity.
Selected bond lengths (Å) and angles (deg): Mn(1)eC(1) 1.768(2), Mn(1)eC(2)
1.772(2), Mn(1)eP(1) 2.2118(7), C(33)eC(34) 1.307(3), C(34)eC(35) 1.315(3), C(1)e
Mn(1)eC(2) 91.6(1), C(1)eMn(1)eP(1) 97.9(1), C(2)eMn(1)eP(1) 92.1(1), C(33)e
C(34)eC(35) 172.2(2).
C
C C
MePh2P
8 (27%)
Scheme 5.

K.I. Utegenov et al. / Journal of Organometallic Chemistry 696 (2011) 3408e3414
3411
R
[M]
R
R
[M]
[M]
Scheme 6.
G
E
F
Chart 1. Possible isomers of a monosubstituted allene complex.
the carbon atom bearing the PMePh2 group MneC(8) ¼ 2.1282(16)
Å is significantly greater than that to the central carbon atom
MneC(9) ¼ 2.0263(16) Å. A similar effect occurs in the parent allene
phosphonioallenyl complexes Cp(CO)2MnꢀeC(þPR13)]C]C(Ph)R.
The protonation of the latter affords the phosphonioallene
complexes Cp(CO)2Mn{h
2-(1,2)-HC(þPR13)]C]C(Ph)R}, rather than
complex Cp(CO)2Mn(
complex C5H4Me(CO)2Mn(
h
2-CH2]C]CH2) [15] and phosphinoallene
the phosphoniovinylcarbene ones Cp(CO)2Mn]C(þPR13)eHC]
h
2-Ph2PC(Ph)]C]C(Tol)H) [16], in
C(Ph)R. All complexes obtained are stereochemically rigid and do
not isomerize into the corresponding
isomers under ambient conditions.
which the metalecarbon distances are very close to those in 9. The
coordinated C]C bond C(8)eC(9) ¼ 1.412(2) Å is longer than the
uncoordinated C]C bond C(9)eC(10) ¼ 1.331(2) Å, these values
being similar to those found in the allene manganese complexes
[15,16] or phosphonioallene complexes of other metals [8ced,12].
The coordination causes the usually linear allene to bend away from
the metal centre, the angle C(8)eC(9)eC(10) (144.82(16)) falls in
the range of angles for h2-coordinated allenes (140e158ꢁ) [11c,12:
Table S1].
h
2-(1,2)-phosphonioallene
4. Experimental
4.1. General
All operations were carried out under an argon atmosphere
using the standard Schlenk techniques. Solvents were purified
according to the standard procedures and distilled under argon
prior to use. IR spectra were recorded on Specord 75 and Specord
M80 IR (Carl Zeiss, Jena) spectrophotometers. 1H NMR, 13C{1H}
NMR, and 31P{1H} NMR spectra were recorded on Bruker Avance
300 and Bruker Avance 400 instruments at 25 ꢁC and referenced to
the residual deuterated solvent signals and external 85% H3PO4,
respectively. Elemental analysis was performed on a Carlo Erba-
1106 analyzer (C, H) and VRA-30 (Carl Zeiss, Jena) X-ray fluores-
cence spectrometer (Mn) in the Microanalysis Laboratory of the
Institute of Organoelement Compounds of the RAS. Complex 1 was
prepared according to the modified procedure of Kolobova et al.
[17]. PPh2Me [18], PPhMe2 [19], PMe3 [20], and 1-phenyl-propynol
[21] were prepared according to known procedures. PPh2CH2PPh2,
PPh2CH2CH2PPh2, and HBF4$OEt2 were purchased from Aldrich and
used as received.
Thus, we proposed a convenient entry to the manganese
phosphonioallene complexes, which consists of the protonation of
the -phosphonioallenyl adducts. It is thought to be applicable for
the preparation of the
2-1,2- or 2,3-phosphonioallene complexes
h
2-1,2-
a
h
of other metals from the corresponding
derivatives.
a- or g-phosphonioallenyl
3. Conclusions
In the present work, we showed that the addition of phosphines
to the manganese allenylidene complexes Cp(CO)2Mn]C]C]
C(Ph)R (R ¼ H, Ph) proceeds selectively at the Ca atom to form the
a-
4.2. Synthesis of the manganese 1-phosphonioallenyl complexes
4.2.1. Synthesis of (h
5-C5H5)(CO)2MnꢀeC(PþPh2Me)]C]CPh2
(2a)
To a solution of complex 1 (366 mg, 1.0 mmol) in n-hexane
(25 mL), methyldiphenylphosphine (0.19 mL, 1.021 mmol) was
added with stirring. The resulted mixture was stirred for 1 h at
room temperature. The orange precipitate formed was filtered off,
washed with n-hexane, and dried by an argon stream to yield
complex 2a (445 mg, 79%). Found (%): C, 74.28; H, 5.01.
C35H28MnO2P. Calculated (%): C, 74.21; H, 4.98. IR,
1824s (CO). 1H NMR (C6D6),
: 1.93 (d, 3H, JPH ¼ 8.3 Hz, Me), 4.41 (s,
5H, Cp), 6.90e7.31 (m, 20H, Ph). 31P NMR (C6D6),
: 15.08 (s).
n
/cmꢀ1: 1894s,
d
d
4.2.2. Synthesis of (h
5-C5H5)(CO)2MnꢀeC(PþPhMe2)]C]CPh2
(2b)
To a solution of complex 1 (110 mg, 0.3 mmol) in CH2Cl2 (2 mL),
phenyldimethylphosphine (0.042 mL, 0.3 mmol) was added with
stirring. The resulted mixture was stirred for 30 min and then
evaporated to dryness. The oily residue was washed with n-hexane
(2 ꢂ 2 mL) and dried in vacuo to yield compound 2b (147 mg, 97%)
Fig. 2. Molecular structure of [(h h
5-C5H5)(CO)2Mn( 2-HC(þPPh2Me)]C]CHPh)]BFꢀ4 (9)
(50% probability displacement thermal ellipsoids). BFꢀ4 anion is omitted for clarity.
Selected bond lengths (Å) and angles (deg): Mn(1)eC(1) 1.8042(18), Mn(1)-C(2)
1.7830(17), Mn(1)eC(8) 2.1282(16), Mn(1)eC(9) 2.0263(16), C(8)eC(9) 1.412(2),
C(9)eC(10) 1.331(2), C(2)eMn(1)eC(1) 86.07(8), C(8)eC(9)eC(10) 144.82(16).
as a deep-brown oil. IR,
n
/cmꢀ1: 1898s, 1828s (CO). 1H NMR (C6D6),
d
: 1.42 (br.s, 6H, Me), 4.50 (br.s, 5H, Cp), 7.05e7.54 (m, 15H, Ph). 31
P
NMR (C6D6),
d: 12.48 (s).

3412
K.I. Utegenov et al. / Journal of Organometallic Chemistry 696 (2011) 3408e3414
4.2.3. Synthesis of (
h
5-C5H5)(CO)2MnꢀeC(PþMe3)]C]CPh2 (2c)
added with stirring. The reaction mixture was stirred for 30 min on
cooling (dry-ice/ethanol bath) and then diethyl ether (20 mL) was
added. The precipitate formed was filtered off, washed with diethyl
ether, dried by an argon stream, and chromatographed on a silica
gel column at ꢀ20 to ꢀ40 ꢁC. The light-yellow fraction was eluted
with a CH2Cl2eacetone (10:1) mixture. After concentration of the
eluate and reprecipitation with diethyl ether, complex 4a (96.2 mg,
74 %) was obtained as a yellow powder. Found (%): C, 64.24; H, 4.46;
P, 4.48. C35H29BF4MnO2P. Calculated (%): C, 64.25; H, 4.47; P, 4.73.
To a solution of complex 1 (146.5 mg, 0.4 mmol) in n-hexane
(10 mL), a solution of trimethylphosphine in diethyl ether (0.092 M,
c ¼ 7 mg/mL, 5 mL, 0.46 mmol) was added with stirring. The reac-
tion mixture was stirred for 1 h at room temperature and then
evaporated. The residue was washed with n-hexane, filtered off,
and dried by an argon stream. Complex 2c (110.8 mg, 63%) was
obtained as an orange powder. Found (%): C, 67.69; H, 5.41; Mn,
12.30. C25H24MnO2P. Calculated (%): C, 67.88; H, 5.47; Mn, 12.42. IR,
nCO/cmꢀ1 (CH2Cl2): 1898s, 1828s. 1H NMR (C6D6),
d: 0.92 (d, 9H,
IR, n d:
/cmꢀ1 (CH2Cl2): 2002s, 1950s (CO). 1H NMR (acetone-d6),
JPH ¼ 11.8 Hz, Me), 4.44 (s, 5H, Cp), 7.07e7.51 (m, 10H, Ph). 31P NMR
2.08 (d, 3H, JPH ¼ 13.7 Hz, Me), 4.16 (d, 1H, JPH ¼ 6.7 Hz, ]CH), 5.10
(C6D6),
d
: 12.45 (s).
(s, 5H, Cp), 7.08e7.87 (m, 20H, Ph). 31P NMR (acetone-d6)
(s). MS (ESI), m/z: 566.866.
d: 27,04
4.2.4. Synthesis of (h
5-C5H5)(CO)2MnꢀeC(þPPh2CH2PPh2)]C]
CPh2 (2d)
4.3.2. [(h h
5-C5H5)(CO)2Mn{ 2-CH(PþPhMe2)]C]CPh2}]BFꢀ4 (4b)
To a solution of bis(diphenylphosphino)methane (461.3 mg,
1.2 mmol) in n-hexane (75 mL), a solution of complex 1 (366 mg,
1.0 mmol) in n-hexane (12 mL) was added with stirring. The reac-
tion mixture was stirred for 2 h at room temperature. The orange
precipitate formed was filtered off, washed with n-hexane, and
dried by an argon stream to yield complex 2d (546 mg, 73 %). Found
(%): C, 75.35; H, 5.01; P, 8.64. C47H37MnO2P2. Calculated (%): C,
To a cooled (ꢀ70 ꢁC) solution of HBF4 (0.066, 0.480 mmol) in
Et2O (10 mL), complex 2b (69 mg, 0.137 mmol) was added. The
reaction mixture was stirred until the temperature rose to 25 ꢁC.
The precipitate formed was filtered off, washed with diethyl ether,
and dried by an argon stream to yield complex 4b (55.3 mg, 68 %) as
a yellow powder. IR,
(acetone-d6), : 1.70 (br.s, 6H, Me), 3.71 (br.s, 1H, ]CH), 4.98 (br.s,
5H, Cp), 7.00e8.00 (m, 15H, Ph). 31P NMR (acetone-d6),
: 29.95 (s).
n
/cmꢀ1 (CH2Cl2): 2000s, 1950s (CO). 1H NMR
d
75.20; H, 4.97; P, 8.25. IR,
n
/cmꢀ1 (CH2Cl2): 1894s, 1820s (CO). 1H
d
NMR (C6D6),
d
: 4.01 (d, 2H, JPH ¼ 13.6 Hz, CH2), 4.44 (s, 5H, Cp),
6.92e7.67 (m, 30H, Ph). 31P NMR (C6D6),
d
: ꢀ27.04 (d, 1P,
4.3.3. [(
h
5-C5H5)(CO)2Mn{ 2-CH(PþMe3)]C]CPh2}]BFꢀ4 (4c)
h
JPP ¼ 58.5 Hz, PPh2CH2), 16.38 (d, 1P, JPP ¼ 58.5 Hz, PþPh2CH2).
To a cooled (ꢀ70 ꢁC) solution of complex 1 (183 mg, 0.5 mmol)
in dichloromethane (10 mL), a solution of trimethylphosphine in
diethyl ether (0.092 M, c ¼ 7 mg/mL, 6 mL, 0.55 mmol) was added
with stirring. The mixture was warmed slowly. At ꢀ30 ꢁC, a violet
color disappeared and the IR spectrum displayed the absorption
bands of complex 2c (1898s, 1828s (CO)). HBF4$OEt2 (0.16 mL,
mmol) was added to the resulted mixture at ꢀ30 ꢁC and the
mixture was stirred on cooling (dry-ice/ethanol bath) for 20 min.
Then diethyl ether (30 mL) was added. The yellow precipitate
formed was filtered off and chromatographed on a silica gel column
at ꢀ40 to 20 ꢁC. The light-yellow fraction was eluted with
a CH2Cl2eacetone (1:10) mixture. After evaporation and repreci-
pitation with diethyl ether, complex 4c (156 mg, 59 %) was obtained
as a yellow powder. Found (%): C, 56.41; H, 4.71. C25H25BF4MnO2P.
4.2.5. Synthesis of [(h
5-C5H5)(CO)2MnꢀeC(]C]CPh2)e
PþPh2CH2]2 (3)
To a solution of complex 1 (309.3 mg, 0.844 mmol) in n-hexane
(150 mL), a solution of bis(diphenylphosphino)ethane (155 mg,
0.389 mmol) in n-hexane (50 mL) was added with stirring. The
reaction mixture was stirred for 2 h at room temperature. The
orange precipitate formed was filtered off, washed with n-hexane,
and dried by an argon stream to yield complex 5e (423.5 mg, 96%
based on dppe). Found (%): C, 73.91; H, 4.54; P, 5.24.
C70H54Mn2O4P2. Calculated (%): C, 74.34; H, 4.81; P, 5.48. IR,
(CH2Cl2): 1892s, 1820s (CO). 1H NMR (C6D6),
: 3.54 (s, 4H, CH2),
4.22 (s, 10H, Cp), 7.0e8.02 (m, 40H, Ph). 31P NMR (C6D6),
: 17.72 (s).
n
/cmꢀ1
d
d
Calculated (%): C, 56.64; H, 4.75. IR,
(acetone-d6),
: 1.58 (d, 9H, JPH ¼ 13.6 Hz, Me), 3.42 (br.s, 1H, ]CH),
n
/cmꢀ1: 2000s, 1950s (CO). 1H
4.2.6. Synthesis of (
h
5-C5H5)(CO)2MnꢀeC(PþPh2Me)]C]C(H)Ph
d
(8)
5.07 (s, 5H, Cp), 7.26e7.66 (m, 10H, Ph). 13C NMR (acetone-d6),
d:
To a cooled (ꢀ70 ꢁC) solution of the ethoxystyrylcarbene
2.88 (d, 1JPC ¼ 76.0 Hz, Me), 9.30 (d, 1JPC ¼ 55.6 Hz, ¼CHP), 86.96 (s,
complex
(h
5-C5H5)Mn(CO)2]C(OEt)e(H)C]C(H)Ph (145.6 mg,
C]C]CPh2), 89.11 (s, Cp), 127.41, 127.48, 128.36, 128.40, 128.56,
2
0.45 mmol), 1 M BCl3 in n-hexane (1.13 mL, 1.12 mmol) was added
dropwise with vigorous stirring. (The mixture became lighter and
an orange precipitate formed.) The resulted mixture was stirred for
3 h at ꢀ50 ꢁC and then triethylamine (1.5 mL, 10.76 mmol) was
added (the mixture darkened immediately and gained a dark-
brown color; the IR spectrum displayed the absorption bands nCO
1994, 1940, nC]C]C 1904 that correspond to the allenylidene
complex 7). When the temperature rose to ꢀ20 ꢁC, degassed water
was added and the mixture was stirred for additional 20 min. The
aqueous layer was separated and the organic layer was washed
twice with degassed water and dried over MgSO4. After filtration,
methyldiphenylphosphine (0.084 mL, 0.45 mmol) was added. The
mixture was stirred for 1 h. The yellow precipitate formed was
filtered off, washed twice with n-hexane, and dried in vacuo to yield
129.78 (s, Ph), 141.35 (d, JPC ¼ 7.4 Hz, ]C]CPh2), 141.35 (d,
3JPC ¼ 3.3 Hz, ]CPh2), 157.98 (d, JPC ¼ 5.7 Hz), 227.93 (s, CO),
3
233.70 (s, CO). 31P NMR (acetone-d6),
d: 33.99 (s).
4.3.4. [(h
5-C5H5)Mn(CO)2ePPh2CH2PþPh2eC(H)]C]CPh2]BFꢀ4 (6)
To a cooled (ꢀ70 ꢁC) solution of complex 2d (75.4 mg, 0.1 mmol)
in dichloromethane (2 mL), HBF4$OEt2 (0.023 mL, 0.167 mmol) was
added with stirring. The reaction mixture was stirred on cooling
(dry-ice/ethanol bath) for 30 min and then diethyl ether (15 mL)
and n-hexane (10 mL) were added subsequently. The dark-yellow
crystalline precipitate was filtered off, washed with diethyl ether,
and dried by an argon stream to yield complex 6 (75 mg, 89%). IR,
n/
cmꢀ1 (CH2Cl2): 1940s, 1866s (CO). 1H NMR (acetone-d6),
d
: 4.28 (s,
5H, Cp), 4.80 (dd, 2H, JP1,H ¼ 7.8 Hz, JP2,H ¼ 15.9 Hz, CH2), 6.79 (d, 1H,
complex 8 (60 mg, 27%). IR,
n
/cmꢀ1 (n-hexane): 1894s, 1824s (CO).
JPH ¼ 10.3 Hz, ]CH), 6.84e7.80 (m, 30H, Ph). 31P NMR (acetone-d6),
d
: 18.33 (s, 1P, PþPh2CH2), 84.82 (s, 1P, PeMn).
4.3. Protonation of the manganese 1-phosphonioallenyl complexes
4.3.5. [{(h h
5-C5H5)Mn(CO)2( 2-Ph2C]C]C(H)PþPh2CH2)}2](BF4ꢀ)2
4.3.1. [(
h
5-C5H5)(CO)2Mn{
h
2-CH(PþPh2Me)]C]CPh2}]BF4ꢀ (4a)
(5)
To a cooled (ꢀ70 ꢁC) solution of complex 2a (113 mg, 0.2 mmol)
To
a
cooled (ꢀ70 ꢁC) solution of complex
3 (250 mg,
in dichloromethane (4 mL), HBF4$OEt2 (0.03 mL, 0.220 mmol) was
0.221 mmol) in dichloromethane (8 mL), HBF4$OEt2 (0.037 mL,

K.I. Utegenov et al. / Journal of Organometallic Chemistry 696 (2011) 3408e3414
3413
0.265 mmol) was added with stirring. The reaction mixture was
stirred on cooling (dry-ice/ethanol bath) for 30 min and then
diethyl ether (5 mL) and n-hexane (20 mL) were added. The
precipitate formed was filtered off, washed with diethyl ether,
dissolved in dichloromethane (1 mL), and chromatographed on
a silica gel column at ꢀ20 to ꢀ40 ꢁC. The light-yellow fraction was
eluted with a CH2Cl2eacetone (10:1) mixture. After concentration
of the eluate in vacuo and reprecipitation with diethyl ether,
complex 5 (165.1 mg, 57%) was obtained as a yellow powder. Found
(%): C, 64.81; H, 4.29; Mn, 8.40; P, 4.81. C70H56B2F8Mn2O4P2.
with Uiso(H) parameters equal to 1.2 Ueq(Ci) for CH and CH2 groups
and 1.5 Ueq(Cii), where U(Ci) and U(Cii) are, respectively, the
equivalent thermal parameters of the carbon atoms to which the
corresponding H atoms are bonded. All calculations were per-
formed on an IBM PC/AT using the SHELXTL software [25]. The
crystallographic details are given in Table 1.
Acknowledgments
Financial support from the Russian Foundation for Basic
Research (Grants No. 08-03-00846 and 11-03-00819) and from the
Presidium of the Russian Academy of Sciences (Subprogram
“Development of organic synthesis methodology and design of
compounds with valuable applied properties”) is gratefully
acknowledged.
Calculated (%): C, 64.35; H, 4.32; Mn, 8.41; P, 4.74. IR,
n
/cmꢀ1
(CH2Cl2): 2002s, 1950s (CO). 1H NMR (acetone-d6),
d: 2.8e3.0 (CH2,
overlapped with the H2O signals), 3.95 (m, 2H, JPH ¼ 4.20 Hz, ]CH),
4.93 (s, 10H, Cp), 6.92e8.20 (m, 40H, Ph). 31P NMR (acetone-d6),
d:
35.10 (s).
4.3.6. [(h h
5-C5H5)(CO)2Mn{ 2-CH(PþPh2Me)]C]C(H)Ph}]BFꢀ4 (9)
Appendix. Supplementary data
To a cooled (ꢀ70 ꢁC) solution of complex 8 (60 mg, 0.12 mmol)
in dichloromethane (4 mL), HBF4$OEt2 (0.028 mL, 0.2 mmol) was
added with stirring. The reaction mixture was stirred on cooling
(dry-ice/ethanol bath) for 30 min and then diethyl ether (20 mL)
was added. The precipitate formed was filtered off, washed with
diethyl ether, and dried in vacuo to yield complex 9 (62 mg, 89%). IR,
CCDC 830693 and 830694 contain the crystallographic data for
compounds 6 and 9, respectively. These data can be obtained free of
charge from the Cambridge Crystallographic Data Center via http://
www.ccdc.cam.ac.uk/conts/retrieving.html.
n
/cmꢀ1 (CH2Cl2): 2000 (v.s, CO), 1950 (v.s, CO).
References
[1] (a) M.I. Bruce, Chem. Rev. 98 (1998) 2797;
4.4. X-ray crystal structure determination of compounds 6 and 9
(b) V. Cadierno, M.P. Gamasa, J. Gimeno, Eur. J. Inorg. Chem. 2001 (2001) 571;
(c) V. Cadierno, J. Gimeno, Chem. Rev. 109 (2009) 3512;
(d) V. Cadierno, S.E. Garcia-Garrido, Top. Organomet. Chem. 30 (2010) 151;
(e) N. Mantovani, L. Marvelli, R. Rossi, V. Bertolasi, C. Bianchini, I. de los Rios,
M. Peruzzini, Organometallics 21 (2002) 2382;
Single-crystal X-ray diffraction experiments were carried out
with a Bruker SMART APEX2 CCD area detector diffractometer
using graphite monochromated Mo-K
a
radiation (
l
¼ 0.71073 Å,
u-
(f) N. Mantovani, P. Bergamini, A. Marchi, L. Marvelli, R. Rossi, V. Bertolasi,
V. Ferretti, I. de los Rios, M. Peruzzini, Organometallics 25 (2006) 416.
[2] (a) I. Dragutan, V. Dragutan, Platinum Metals Rev. 50 (2) (2006) 81;
(b) R. Castarlenas, C. Fischmeister, C. Bruneau, P.H. Dixneuf, J. Mol. Catal. A:
Chem. 213 (2004) 31;
(c) C. Bruneau, P.H. Dixneuf, Angew. Chem. Int. Ed. 45 (2006) 2176.
[3] (a) H. Berke, P. Härter, G. Huttner, L. Zsolnai, Z. Naturforsch., Teil B 36 (1981)
929;
scans) at 100 K. Low temperature of the crystals was maintained
with a Cobra (Oxford Cryosystems) N2 gas cryostat. Reflection
intensities were integrated using the SAINT software [22,23] and
semi-empirical method SADABS [24]. The structures were solved by
the direct method and refined by the full-matrix least-squares
against F2 in the anisotropic (for non-hydrogen atoms) approxi-
mation. All H(C) atoms were placed in the geometrically calculated
positions and refined in isotropic approximation in riding model
(b) H. Berke, U. Grössmann, G. Huttner, O. Orama, Z. Naturforsch., Teil B 39
(1984) 1759;
(c) N.E. Kolobova, L.L. Ivanov, O.S. Zhvanko, O.M. Khitrova, A.S. Batsanov,
Yu.T. Struchkov, J. Organomet. Chem. 265 (1984) 271;
(d) H. Fischer, D. Reindl, C. Troll, F. Leroux, J. Organomet. Chem. 490 (1995)
221;
(e) V. Cadierno, M.P. Gamasa, J. Gimeno, M.C. López-González, J. Borge,
S. Garcıá-Granda, Organometallics 16 (1997) 4453;
(f) M.A. Esteruelas, A.V. Gómez, A.M. López, J. Modriego, E. Oñate, Organo-
metallics 17 (1998) 5434;
Table 1
Crystallographic details for 6 and 9.
Compound
6
9
(g) M. Jimenez-Tenorio, M.D. Palacios, M.C. Puerta, P. Valerga, J. Organomet.
Chem. 689 (2004) 2776;
Chemical formula
Formula weight
Crystal system
Space group
Crystal color and shape
Crystal size
a (Å)
C47H38BF4MnO2P2
838.46
Triclinic
C29H25BF4MnO2P
578.21
(h) A.I.F. Venâncio, M. Fátima, C.G. da Silva, Luísa M.D.R.S. Martins, J.J.R.F. da
Silva, A.J.L. Pombeiro, Organometallics 24 (2005) 4654;
(i) Y. Nishimura, Y. Arikawa, T. Inoue, M. Onishi, Dalton Trans. (2005) 930;
(j) Y. Arikawa, T. Asayama, C. Tanaka, S. Tashita, M. Tsuji, K. Ikeda,
K. Umakoshi, M. Onishi, Organometallics 28 (2008) 1227.
[4] (a) M. Peruzzini, P. Barbaro, V. Bertolasi, C. Bianchini, I. de los Rios,
N. Mantovani, L. Marvelli, R. Rossi, Dalton Trans. (2003) 4121;
(b) C. Coletti, L. Gonsalvi, A. Guerriero, L. Marvelli, M. Peruzzini, G. Reginato,
N. Re, Organometallics 29 (2010) 5982.
Monoclinic
P 2(1)/c (no. 14)
Yellow, prism
0.31 ꢂ 0.28 ꢂ 0.14
10.146(3)
16.387(3)
16.272(3)
90.00
97.619(11)
90.00
2681.4(10)
4
P ꢀ1 (no. 2)
Dark-yellow, prism
0.21 ꢂ 0.16 ꢂ 0.14
10.6943(5)
13.4105(7)
15.2331(8)
98.5720(10)
110.0960(10)
94.1250(10)
2010.83(18)
2
b (Å)
c (Å)
a
b
g
(ꢁ)
(ꢁ)
(ꢁ)
[5] (a) V.V. Krivykh, E.S. Taits, S.P. Solodovnikov, I.V. Glukhov, M.Yu. Antipin,
N.A. Ustynyuk, Izv. Akad. Nauk, Ser. Khim. (2007) 1423, Russ. Chem. Bull. 56
(2007) 5982;
V (Å3)
Z
(b) V.V. Krivykh, D.A. Valyaev, K.I. Utegenov, A.M. Mazhuga, E.S. Taits,
O.V. Semeikin, P.V. Petrovskii, I.V. Glukhov, N.A. Ustynyuk, Eur. J. Inorg. Chem.
(2011) 201.
T (K)
100
1.385
0.466
100
1.432
0.605
Dc (g cmꢀ3
)
[6] Complex
7 was generated in situ from the ethoxycarbene complex
m
(mmꢀ1
)
Cp(CO)2Mn¼C(OEt)eC(H)¼C(H)Ph in two steps: in the first step, addition of
BCl3 to the carbene complex results in the elimination of the ethoxy group to
form the carbyne complex [Cp(CO)2MnhCeC(H)¼C(H)Ph]BCl4 (cf., for
example, E.O. Fischer, H.-J. Kalder, A. Frank, F.H. Köhler, G. Huttner, Angew.
Chem. Int. Ed. Engl. 15 (1976) 623); in the second step, deprotonation of the
latter with Et3N affords the allenylidene complex 7.
Scan range (ꢁ)
Unique reflections
Reflections used jI > 2
Rint
1.91 <
9710
q
< 28.0
1.77 <
7839
q < 30.3
s(I)j
6683
0.0578
0.0456, wR2 ¼ 0.0972
0.0794, wR2 ¼ 0.1106
0.984
0.500, ꢀ0.402
6363
0.0258
0.0372, wR2 ¼ 0.0719
0.0508, wR2 ¼ 0.0770
1.011
0.641, ꢀ0.475
Final R indices jI > 2
R indices (all data)
Goodness-of-fit
s(I)j
[7] C.P. Casey, S. Kraft, D.R. Powell, M. Kavana, J. Organomet. Chem. 617e618
(2001) 723.
[8] (a) V.V. Krivykh, E.S. Taits, M.I. Rybinskaya, Izv. Akad. Nauk., SSSR, Ser. Khim.
(1987) 2866, Bull. Acad. Sci. USSR, Div. Chem. Sci. 36 (1987) 2663;
Max, Min Dr/e (Åꢀ3
)

3414
K.I. Utegenov et al. / Journal of Organometallic Chemistry 696 (2011) 3408e3414
(b) V.V. Krivykh, E.S. Taits, P.V. Petrovskii, Yu. T. Struchkov, A.I. Yanovskii,
Mendeleev Commun. (1991) 103;
(c) M.A. Esteruelas, F.J. Lahoz, M. Martin, E. Oñate, L.A. Oro, Organometallics 6
(1997) 4572;
rearrangements of the monosubstituted allene ligands in the iron and chro-
mium complexes (M.I. Rybinskaya, V.V. Krivykh, O.V. Gusev, E.S. Il’minskaya,
Izv. Akad. Nauk., SSSR, Ser. Khim. (1981) 2839; Bull. Acad. Sci. USSR, Div.
Chem. Sci. 30 (1981) 2371).
(d) M.A. Bennett, L. Kwan, A.D. Rae, E. Wenger, A.C. Willis, J. Chem. Soc., Dalton
Trans. (2002) 226.
[9] B. Foxman, B. Marten, A. Rosan, S. Raghu, M. Rosenblum, J. Am. Chem. Soc. 99
(1977) 2160.
[10] (a) V.V. Krivykh, M.V. Barybin, P.V. Petrovskii, Izv. Akad. Nauk., Ser. Khim.
(1994) 1488, Russ. Chem. Bull. 13 (1994) 1411;
[14] A. Maki, R.A. Toth, J. Mol. Spectrosc. 17 (1965) 136.
[15] D. Lentz, S. Willemsen, Organometallics 18 (1999) 3962.
[16] Y. Orten, N. Lugan, R. Mathieu, J. Chem. Soc., Dalton Trans. (2005) 1620.
[17] N.E. Kolobova, L.L. Ivanov, O.S. Zhvanko, V.R. Derunov, I.I. Chechulina, Izv.
Akad. Nauk SSSR, Ser. Khim. (1982) 2632, Bull. Akad. Sci. USSR, Div. Chem. Sci.
(1982) 2328 (Engl. Transl.).
(b) V.V. Krivykh, I.V. Glukhov, Mendeleev Commun. 20 (2010) 177.
[11] (a) B.L. Shaw, A.J. Stringer, Inorg. Chim. Acta Rev. 7 (1973) 1;
(b) F.L. Bowden, R. Giles, Coord. Chem. Rev. 20 (1976) 81;
(c) S. Otsuka, A. Nakamura, Adv. Organomet. Chem. 14 (1976) 245;
(d) W.M. Jones, J. Klosin, Adv. Organomet. Chem. 42 (1998) 147;
(e) T. Bai, S. Ma, G. Jia, Coord. Chem. Rev. 253 (2009) 423.
[12] W.H. Ang, R.L. Cordiner, A.F. Hill, T. L Perry, J. Wagler, Organometallics 28
(2009) 5568.
[13] There are reports on the reversible haptotropic processes: the degenerated
rearrangements of the tetramethylallene complexes of iron (B. Ben-Shoshan,
R. Pettit, J. Am. Chem. Soc. 89 (1967) 2231) and platinium (K. Vriese, H.C.
Volger, A.P. Praat, J. Organomet. Chem. 21 (1970) 467). The non-degenerated
[18] V.D. Bianco, S. Doronzo, K.J. Reimer, A.G. Shaver, P. Fiess, H.C. Clark, Inorg.
Synth. 16 (1976) 155.
[19] R.F. Benn, J.C. Briggs, C.A. McAuliffe, J. Chem. Soc., Dalton Trans. (1984) 293.
[20] K.L. Marsi, J.E. Oberlander, J. Am. Chem. Soc. 95 (1973) 200.
[21] M.M. Midland, J. Org. Chem. 40 (1975) 2250.
[22] SAINTPlus. Data reduction and correction program v. 6.01. Bruker AXS,
Madison, Wisconsin, USA, 1998.
[23] SMART. Bruker molecular analysis research tool, v. 5.059. Bruker AXS, Madi-
son, Wisconsin, USA, 1998.
[24] G.M. Sheldrick, SADABS v.2.01, Bruker/Siemens area detector absorption
correction program. Bruker AXS, Madison, Wisconsin, USA, 1998.
[25] G.M. Sheldrick, SHELXTL-97, version 5.10. Bruker AXS Inc., Madison, 1997.