An unusual product from the reaction of C(PPh3)2 with [Mn2(CO)10]: Formation and crystal structure of [Mn(OPPh3)2{O2CC(PPh3) 2}2][Mn(CO)5]2

Article abstract of DOI:10.1002/zaac.200800119

The carbodiphosphorane C(PPh₃)₂ (1) reacts with [Mn₂(CO)₁₀] in THF to produce quantitatively the salt-like complex (HC{PPh₃}₂)[Mn(CO)₅] (2) as THF solvate. If the reaction is carried out in 1,2-dimethoxyethane (DME) small amounts of [Mn(OPPh₃)₂{O₂CC(PPh ₃)₂}₂][Mn(CO)₅]₂ (3) as DME solvate along with solvent free 2 as the main product were isolated. Proton abstraction from the solvent led to the formation of 2; the ligands OPPh ₃ and O₂CC(PPh₃)₂}₂ of 3 are the results of a side reaction from [Mn₂(CO)₁₀] and 1 in a Wittig type manner. From the reaction in benzene small amounts of 3 were also obtained, crystallizing as benzene solvate 3·4C₆H ₆. The crystal structures of 2·THF, 2, 3·1.75DME and 3·4C₆H₆ are reported. The compounds are further characterized by IR and ³¹P NMR spectroscopy.

Full text of DOI:10.1002/zaac.200800119

DOI: 10.1002/zaac.200800119
An Unusual Product from the Reaction of C(PPh3)2 with [Mn2(CO)10]:
Formation and Crystal Structure of [Mn(OPPh3)2{O2CC(PPh3)2}2][Mn(CO)5]2
Wolfgang Petz*, Florian Öxler, Ramona Ronge, and Bernhard Neumüller*
Marburg Germany, Fachbereich Chemie der Philipps-Universität
Received 27th, March 2008.
Professor Heinrich Nöth zum 80. Geburtstag gewidmet
Abstract. The carbodiphosphorane C(PPh3)2 (1) reacts with
[Mn2(CO)10] in THF to produce quantitatively the salt-like com-
plex (HC{PPh3}2)[Mn(CO)5] (2) as THF solvate. If the reaction
is carried out in 1,2-dimethoxyethane (DME) small amounts of
[Mn(OPPh3)2{O2CC(PPh3)2}2][Mn(CO)5]2 (3) as DME solvate
along with solvent free 2 as the main product were isolated. Proton
abstraction from the solvent led to the formation of 2; the ligands
OPPh3 and O2CC(PPh3)2}2 of 3 are the results of a side reaction
from [Mn2(CO)10] and 1 in a Wittig type manner. From the reac-
tion in benzene small amounts of 3 were also obtained, crystallizing
as benzene solvate 3·4C6H6. The crystal structures of 2·THF, 2,
3·1.75DME and 3·4C6H6 are reported. The compounds are
further characterized by IR and 31P NMR spectroscopy.
Keywords: Carbodiphosphorane; Manganese complex; Proton Ab-
straction; Crystal Structure
1 Introduction
bonyl carbon atom occurred to produce the heterocumulene
complex [(CO)4Fe(CCPPh3)] and OPPh3 in a Wittig type
manner [11]. The same was true for [Co2(CO)8]; however,
only a tetranuclear cluster containing the heterocumulene
ligand CCPPh3 could be isolated and characterized by X-
ray analysis [12]. These reactions demonstrate the hard
Lewis base character of 1. Complexes with 1 and group 6
carbonyl compounds [M(CO)6] were mentioned in the lit-
erature, but non of them was sufficiently characterized [13].
Here we report on the outcome of the reaction of 1 with
[Mn2(CO)10] in various solvents.
Many attempts have been made to study the ligand proper-
ties of the carbodiphosphorane C(PPh3)2 (1) towards differ-
ent Lewis acids. 1 has a bent structure [1], and since the
first preparation in 1961 [2], a series of addition compounds
with main group [3Ϫ5] or transition metal Lewis acids
[6Ϫ9] were described and characterized by crystal structure
determinations. However, 1 can not be considered as a nor-
mal Lewis base with a donating pair of electrons at the
carbon atom like CO, isonitriles, N-heterocyclic carbenes
(NHC), or others, because this molecule is equipped with
two occupied HOMO orbitals, which determine its chemis-
try, and the best description of 1 is that of a divalent car-
bon(0) atom stabilized by two phosphine ligands [10].
The number of transition metal carbonyl complexes of 1
is limited to two examples, although nearly all “soft” and
even “hard” ligands L form complexes with 16 electron car-
bonyl fragments of the type (CO)xMǟL. Thus, with
[Ni(CO)4] the yellow complex [(CO)3Ni(C{PPh3}2)] and the
red electron deficient compound [(CO)2Ni(C{PPh3}2)]
could be isolated and characterized by X-ray analyses as
the only established carbonyl derivatives of 1 as yet, and
the outcome of the reaction depends on the choice of the
solvent [9]. When we turned to [Fe(CO)5] no CO substi-
tution was observed but a nucleophilic attack of 1 at a car-
2 Results and Discussion
If 1 was allowed to react with [Mn2(CO)10] in thoroughly
dried THF solution, the salt (HC{PPh3}2)[Mn(CO)5] (2)
was obtained in high yield and crystals could be identified
as 2·THF. The 31P NMR of the THF solution showed only
the signal of the cation at 20.6 ppm. The source of the
proton originates from the solvent; similar results were
found earlier from the reaction of [Co2(CO)8] with 1 and a
catalyzed decomposition of THF into butadiene and H2O
was suggested [12]. Thus, with [Mn2(CO)10] the formation
of the salt-like complex 2 was not surprising. In order to
suppress proton abstraction, we switched to DME as the
solvent. For this purpose DME was heated and stirred with
elemental potassium and distilled prior to use to avoid any
influence of humidity. A slow reaction occurred and, ac-
cording to the low solubility of 1 in DME, a suspension
formed, which within four days of stirring at room tempera-
ture under an atmosphere of argon produced a clear orange
yellow solution. The 31P NMR spectrum of this solution
showed about seven singlets, indicating the formation of
* Prof. Dr. Wolfgang Petz, Prof. Dr. Bernhard Neumüller
Fachbereich Chemie der Universität
D-35032 Marburg
Fax: int.-6421/2825653
E-mail: petz@staff.uni-marburg.de
E-mail: neumuell@chemie.uni-marburg.de
Z. Anorg. Allg. Chem. 2008, 634, 1415Ϫ1420
© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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W. Petz, F. Öxler, R. Ronge, B. Neumüller
different reaction products. The most intense signal at
21.6 ppm is due to the cation (HC{PPh3}2)ϩ, which again
results from proton transfer from the solvent to 1. The
signals at Ϫ10.5 and 26.0 ppm can be attributed to a
compound with a MnC2PPh3 fragment and to Ph3PO,
respectively, probably as a result of a Wittig type reaction,
but their low intensities indicate only a side reaction [11];
the signal at Ϫ3.6 ppm originates from some unreacted 1.
Layering of the DME solution with n-pentane produced
an oil and some yellow needles, which surprisingly turned
were detected. A Wittig type product as supposed from
31P NMR measurements could not be crystallized.
The IR spectrum of 2 shows the typical pattern of the
cation; the carbonyl frequencies of the [Mn(CO)5]Ϫ anion
appear at 1900, 1860, and 1840 cmϪ1 [16]. The IR spectrum
of 3 is very complex and governed by the vibrations of the
aromatic systems; besides the bands of the [Mn(CO)5]Ϫ
anion also bands between 1530 and 1350 cmϪ1 were found
according to νs and νas CO2 vibrations of the O2CC(PPh3)2
ligands, similar to those found in the related compounds
[Cl3In{O2CC(PPh3)2}] [17] and [(CO)4W{O2CC(PPh3)2}]
[18] in which the ligand is bonded in the same manner.
out
to
be
the
salt-like
complex
compound
[Mn(OPPh3)2{O2CC(PPh3)2}2][Mn(CO)5]2 (3) as DME
solvate (3·1.75DME), containing MnII as shown in
Scheme 1. From the oil of the DME solution the solvent
free salt (HC{PPh3}2)[Mn(CO)5] (2) could be isolated as
yellow crystals. When we turned to benzene as the solvent
a slow reaction was observed with formation of a yellow
precipitate and an orange red oil. The 31P NMR of the
solution showed signals which similarly can be assigned to
a Wittig type product; however, after 10 days reaction time
at room temperature the signal of unreacted 1 still domi-
nated. The oil crystallized after about two weeks and the
same cation as from DME solution was isolated; the crys-
tals were identified as 3·4C6H6. In toluene solution the
same behavior was observed.
The unusual formation of the well known ligand
O2CC(PPh3)2 as an adduct of 1 at CO2 [14] can only be
explained with a reaction of the phosphine oxide (from the
Wittig reaction) with [Mn2(CO)10] finally liberating CO2
(equations (1) and (2)) which is immediately consumed by
1 according to equation (3).
3 Crystal Structures
X-ray analyses were performed from all compounds which
could be crystallized. Pale orange crystals of the salt
2·THF suitable for an X-ray analysis formed from THF/
n-pentane. Few yellow needles of 3·1.75DME and big yel-
low blocks of the solvate free salt 2 were obtained from
DME solutions as mentioned above. Yellow orange crystals
of 3·4C6H6 have grown from an orange oil, which sepa-
rated from the benzene reaction mixture. The structures of
2, 2·THF, and of the cation of 3·1.75DME and 3·4C6H6
are shown in Figures 1 and 2, respectively. The crystallo-
graphic data are collected in Table 1; distances and angles
are summarized in Tables 2 and 3. Further complexes with
the O2CC(PPh3)2 ligand have been reported recently coordi-
nated at InCl3 [17] and the (CO)4W fragment [18]; the struc-
ture of the free ligand was presented earlier [14].
3.1 Crystal Structures of 2 and 2·THF
[Mn2(CO)10] ϩ 1 Ǟ “[Mn]ϭCϭCϭPPh3” ϩ OPPh3
OPPh3 ϩ [Mn2(CO)10] Ǟ CO2 ϩ [Mn2(CO)9(PPh3)]
CO2 ϩ 1 Ǟ O2CC(PPh3)2
(1)
(2)
(3)
The molecular structures of 2 and 2·THF are depicted in
Figure 1 (A and B). The incorporation of a solvent mol-
ecule in 2 does not markedly change the parameters of the
cation (HC{PPh3}2)ϩ; the P(1)-C(6)-P(2) angle is slightly
less acute in the solvent free compound. Whereas in 2 the
proton of the cation forms a contact to one carbonyl oxy-
gen atom of the anion (C(6)-H(1)·····O(1) ϭ 341.1(2) pm)
as shown in structure A, in 2·THF (structure B) a similar
contact between the proton and the oxygen atom of the
THF molecule exists (C(6)-H(1)·····O(6) ϭ345.5(5) pm);
the THF molecule is disordered in two positions but only
one is shown. The anion of 2·THF forms a nearly perfect
trigonal bipyramide which is slightly distorted in 2. Other
salt-like compounds of the type (HC{PPh3}2)(X) were de-
scribed with various counterions X [19].
Scheme 1
The formation of MnII probably arises from dispro-
portionation of formal Mn0 in [Mn2(CO)10] under the influ-
ence of the oxo ligands. The components of 3 can be
detected in the 31P NMR spectrum of the DME solution
and the formation of 3 is apparently due to good crystalli-
zation properties. A weak and broad signal at 61 ppm can
be assigned to [Mn2(CO)9(PPh3)]; the 31P NMR shifts of
such compounds are found in this region [15]. According
to the paramagnetism of 3 no signals of the complex cation
3.2 Crystal Structure of 3·1.75DME
The cation of 3·1.75DME, containing the ligands Ph3PO
and O2CC(PPh3)2, is located on a twofold axis and the
[Mn(CO)5]Ϫ anion is disordered in two positions (0.75/
0.25); the molecular structure of the cation is depicted in
Figure 2. The OPPh3 ligands are in a cis arrangement and
the Mn2ϩ ion is surrounded by six oxygen atoms in a dis-
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An Unusual Product from the Reaction of C(PPh3)2 with [Mn2(CO)10]
Table 1 Crystal data of complexes 2, 2·THF, 3·4C6H6, and 3·1.75DME
2
2·THF
3·4C6H6
3·1.75DME
formula
MW
cryst size/mm
space group
a/pm
C42H31MnO5P2
732.59
0.28ϫ0.19ϫ0.17
P21/c (No. 14)
1374.6(1)
C46H39MnO6P2
804.69
C146H114Mn3O16P6
2475.01
C129H107.5Mn3O19.5P6
2320.29
0.58ϫ0.07ϫ0.05
I2/a (No. 15)
1910.7(2)
0.39ϫ0.38ϫ0.15
0.3ϫ0.06ϫ0.06
¯
¯
P1 (No. 2)
P1 (No. 2)
1250.9(1)
1724.6(1)
b/pm
c/pm
1916.1(1)
1386.4(1)
1344.8(1)
1455.2(1)
1825.3(1)
2229.0(1)
2445.5(2)
2735.0(4)
α/deg
β/deg
62.70(1)
69.71(1)
84.22(1)
69.39(1)
90.32(1)
98.19(2)
γ/deg
75.46(1)
70.72(1)
volume/pm3
crystal system
Z
3651.5(5) ϫ 106
monoclinic
4
2026.7(3) ϫ 106
triclinic
6290.0(6) ϫ 106
triclinic
12649(2) ϫ 106
monoclinic
4
2
4
dcalcd
1.333
173
4.9
1.319
193
4.5
1.307
100
4.38
1.218
193
4.33
temp/K
μ/cmϪ1
2θmax/deg
radiation
diffractometer
index range
52.01
MoKα
52.33
MoKα
51.92
MoKα
52.5
MoKα
IPDS II (Stoe)
Ϫ16 Ն h Ն 16
Ϫ23 Ն k Ն 23
Ϫ17 Ն l Ն 17
51014
7113 (Rint ϭ 0.0834)
3962 (F0 > 4σ(F0))
SHELXL-97 [29]
456
IPDS II (Stoe)
Ϫ23 Ն h Ն 23
Ϫ29 Ն k Ն 30
Ϫ33 Ն l Ն 33
29546
8098 (Rint ϭ 0.0555)
5847 (F0 > 4σ(F0))
SHELXL-97 [29]
546
IPDS II (Stoe)
Ϫ21 Ն h Ն 21
Ϫ22 Ն k Ն 22
Ϫ27 Ն l Ն 27
83721
24434 (Rint ϭ 0.1351)
11446 (F0 > 4σ(F0))
SHELXH-97 [30]
1541
IPDS I (Stoe)
Ϫ23 Ն h Ն 23
Ϫ29 Ն k Ն 30
Ϫ33 Ն l Ն 33
62227
12480 (Rint ϭ 0.2097)
4070 (F0 > 4σ(F0))
SHELXL-97 [29]
706
no. of rflns collected
no. of indep rflns
no. of observed rflns
refinement against F2
parameters
structure solution
direct methods,
SIR-92 [31]
Patterson method
(SHELXTL-97-Plus [32]
direct methods,
SIR-92 [31]
direct methods,
SIR-92 [31]
H-atoms
calculated positions with common displacement parameter
H(1) was refined free
R1
0.0304
0.0492
0.27
0.0386
0.1032
0.39
0.0514
0.0836
0.629
0.0586
0.1406
0.458
wR2 (all data)
max electron density left (e/pm3) ϫ 10Ϫ6
some [Ph3PO(EX3)] (E ϭ B, Al; X ϭ F, Cl, Br) addition
compounds for which a mean value of 152 pm was esti-
mated [23, 24]. The Mn-O-P bond angle amounts to
149.2(2)° being more acute than that in [(Ph3PO)2MnCl2]
(156.0(4)°) where the manganese atom adopts a tetrahedral
environment; in Ph3PO adducts with several main group
Lewis acids related angles between 123° and 180° were
found [24]. The bite angle O-C-O of the O2CC(PPh3)2
ligand amounts to 121.3(5)°, and is slightly larger than
Table 2 Selected bond lengths/pm and angles/° in 2·THF/2
Mn(1)ϪC(1)
Mn(1)ϪC(3)
Mn(1)ϪC(5)
O(2)ϪC(2)
O(4)ϪC(4)
P(1)ϪC(6)
P(1)ϪC(13)
P(2)ϪC(6)
P(2)ϪC(31)
C(6)ϪH(1)
C(6)ϪP(1)ϪC(7) 115.0(1)/113.9(1)
C(6)ϪP(1)ϪC(19) 113.3(1)/115.9(1)
C(6)ϪP(2)ϪC(31) 113.2(1)/113.1(1)
P(1)ϪC(6)ϪP(2) 130.3(2)/133.8(1)
P(2)ϪC(6)ϪH(1) 115(2)/112(1)
180.1(3)/182.3(3)
180.6(3)/179.6(3)
182.3(3)/181.5(3)
117.0(3)/116.8(3)
115.3(3)/116.9(3)
169.4(2)/169.3(2)
181.1(2)/180.4(2)
170.0(3)/170.3(3)
179.7(2)/180.9(2)
0.88(3)/0.83(2)
Mn(1)ϪC(2)
Mn(1)ϪC(4)
O(1)ϪC(1)
O(3)ϪC(3)
O(5)ϪC(5)
P(1)ϪC(7)
P(1)ϪC(19)
P(2)ϪC(25)
P(2)ϪC(37)
178.3(3)/178.8(2)
180.6(3)/179.2(3)
115.9(4)/115.3(3)
115.9(3)/116.6(3)
114.4(4)/116.3(3)
181.2(2)/180.3(2)
180.5(2)/180.8(2)
180.7(2)/180.8(2)
181.5(2)/180.8(2)
that
in
[(CO)4W(O2CC{PPh3}2)]
or
that
in
C(6)ϪP(1)ϪC(13) 108.0(1)/105.8(1)
C(6)ϪP(2)ϪC(25) 110.6(1)/109.4(1)
C(6)ϪP(2)ϪC(37) 112.3(1)/113.0(1)
P(1)ϪC(6)ϪH(1) 115(2)/114(1)
[InCl3(O2CC{PPh3}2)], where angles of 117.6(5)° [18] and
119.6(8)° [17], respectively, were found; in the free ligand an
angle of 127.7(2) was recorded [14]. The dihedral angle
O2C/CP2 has opened to 24° from 10° in the free ligand; a
similar effect was observed in other compounds with
O2CC(PPh3)2 acting as chelating ligand. The other param-
eters have changed only slightly upon complex formation;
the C-C distance has decreased by about 1 pm whereas the
C-O distances have increased in the same order [17, 18].
torted octahedral environment with trans O-Mn-O angles
of about 150° [20]. The Mn2ϩ ion belongs to two planar
four-membered rings. The O(3)-Mn-(O3Ј) angle (97.1(2)°)
is larger than that expected for an octahedral arrangement
but smaller than that if we consider the Mn atom being
surrounded by four ligands in an approximately tetrahedral
environment. As in the benzene solvate (see below) three
types of Mn-O distances are measured with distances of
208.5(3), 219.7(3), and 228.1(3) pm. The P-O bond length
amounts to 149.8(4) pm, and is only slightly longer than
that in the free OPPh3 molecule (148.3(2) pm) [21] and in
[(Ph3PO)2MnCl2] (148.8(6) pm) [22], but is shorter than in
3.3 Crystal Structure of 3·4C6H6
The structural parameters of the cation have not changed
markedly relative to those in the DME solvate and is there-
fore not depicted. Two halves of the benzene molecules are
arranged around an inversion center and one of the
[Mn(CO)5]Ϫ anions is disordered. The two dihedral angles
Z. Anorg. Allg. Chem. 2008, 1415Ϫ1420
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W. Petz, F. Öxler, R. Ronge, B. Neumüller
Fig. 2 Molecular structure of the cation of 3·1.75DME showing
the atom numbering scheme (40 % probability for thermal ellip-
soids); the H atoms at the phenyl rings and the solvent molecules
are omitted for clarity.
Table 3 Selected bond lengths/pm and angles/° in the cation of
3·1.75DME
Mn(1)ϪO(3)
Mn(1)ϪO(1)
C(1)ϪC(2)
C(1)ϪP(2)
208.5(3)
228.1(3)
148.0(6)
172.3(5)
127.7(5)
97.1(2)
107.6(1)
91.1(1)
94.7(1)
99.5(1)
150.2(1)
59.2(1)
112.6(4)
130.0(3)
121.3(5)
62.4(2)
Mn(1)ϪO(2)
Mn(1)ϪC(2)
C(1)ϪP(1)
C(2)ϪO(1)
219.7(3)
257.2(5)
172.3(5)
126.5(5)
149.8(4)
91.1(1)
107.6(1)
151.9(1)
150.2(1)
59.2(1)
94.7(1)
88.4(1)
117.2(4)
121.0(4)
117.6(4)
58.6(2)
Fig. 1 Molecular structures of 2 (A) and 2·THF (B) showing the
atom numbering scheme (40 % probability for thermal ellipsoids);
only one position of the disordered THF molecule is drawn; the H
atoms at the phenyl rings are omitted for clarity.
C(2)ϪO(2)
O(3)ϪP(3)
O(3)ϪMn(1)ϪO(3Ј)
O(3)ϪMn(1)ϪO(2)
O(3)ϪMn(1)ϪO(2Ј)
O(3Ј)ϪMn(1)ϪO(1Ј)
O(2)ϪMn(1)ϪO(1Ј)
O(3Ј)ϪMn(1)ϪO(1)
O(2)ϪMn(1)ϪO(1)
C(2)ϪC(1)ϪP(2)
P(2)ϪC(1)ϪP(1)
O(1)ϪC(2)ϪC(1)
O(1)ϪC(2)ϪMn(1)
C(2)ϪO(1)ϪMn(1)
P(3)ϪO(3)ϪMn(1)
O(3Ј)ϪMn(1)ϪO(2)
O(3Ј)ϪMn(1)ϪO(2Ј)
O(2)ϪMn(1)ϪO(2Ј)
O(3)ϪMn(1)ϪO(1Ј)
O(2Ј)ϪMn(1)ϪO(1Ј)
O(3)ϪMn(1)ϪO(1)
O(1Ј)ϪMn(1)ϪO(1)
C(2)ϪC(1)ϪP(1)
O(1)ϪC(2)ϪO(2)
O(2)ϪC(2)ϪC(1)
O(2)ϪC(2)ϪMn(1)
C(2)ϪO(2)ϪMn(1)
O2C/CP2 are nearly equal amounting to 23° and 25°. Like
in the DME solvate three different pairs of Mn-O distances
are found. The shortest ones are the Mn-O(P) bond lengths
with 208.8(2) and 210.5(2) pm; they are slightly longer than
those in [(Ph3PO)2MnCl2] (206.9(6) pm) [24]. The Mn-O
bonds to the O2CC(PPh3)2 ligand differ by about 7 pm: the
longer ones are those approximately trans to OPPh3 with a
mean value of 226.6(2) pm.
88.2(3)
149.2(2)
91.6(3)
of 280.0 kcal/mol but for the suggested complexes
[CO)5Wǟ1] or [Cl2Beǟ1] similarly high proton affinities of
254 kcal/mol were calculated, a consequence of the second
HOMO orbital of 1 [25]. Although 1 is stable in THF solu-
tion we know from various experiments that its addition
compounds are able to abstract protons from solvents like
THF, halocarbons, DME, DMSO, and related ones to pro-
duce the cation (1H)ϩ; even the stable complexes [(CO)n-
Niǟ1] (n ϭ 2, 3) deprotonate CH2Cl2 with cation forma-
4 Conclusion
The difficulties to characterize or even to obtain complexes
of the general type [(L)xMǟ1]n either with low valent tran-
sition metal carbonyl compounds or with other Lewis acids
probably is the result of the high reactivity of such species.
Calculations have shown that 1 has a strong proton affinity
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An Unusual Product from the Reaction of C(PPh3)2 with [Mn2(CO)10]
5 Experimental Section
Fortsetzung Table 3 Selected bond lengths/pm and angles/° in the
cation of 3·4C6H6
All operations were carried out under an argon atmosphere in dried
and degassed solvents using Schlenk techniques. The solvents were
thoroughly dried and freshly distilled prior to use. The IR spectra
were run on a Nicolet 510 spectrometer. For the 31P NMR spectra
we used the instrument Bruker AC 200. 1 was prepared according
to the modified literature procedure [28]; commercially available
[Mn2(CO)10] was sublimed prior to use.
Mn(1)ϪO(5)
Mn(1)ϪO(1)
Mn(1)ϪO(4)
Mn(1)ϪC(40)
C(2)ϪO(1)
C(1)ϪC(2)
C(1)ϪP(1)
C(40)ϪO(4)
208.8(2)
219.7(2)
226.1(2)
256.2(4)
127.4(4)
147.8(4)
172.8(4)
126.4(4)
172.4(3)
149.5(3)
93.5(1)
110.97(9)
92.66(9)
93.25(9)
95.66(8)
151.84(9)
59.49(8)
90.56(9)
88.0(2)
Mn(1)ϪO(6)
Mn(1)ϪO(3)
Mn(1)ϪO(2)
Mn(1)ϪC(2)
C(2)ϪO(2)
C(1)ϪP(2)
C(40)ϪO(3)
C(39)ϪC(40)
210.5(2)
220.0(2)
227.1(2)
256.2(3)
126.9(4)
172.4(4)
128.5(4)
147.8(5)
179.5(3)
149.4(2)
92.36(9)
108.64(9)
147.53(9)
152.21(9)
59.67(8)
96.07(9)
97.33(9)
91.2(2)
116.3(3)
130.6(2)
121.1(3)
90.7(2)
112.8(3)
121.1(3)
117.6(3)
150.2(2)
C(39)ϪP(3)
O(5)ϪP(5)
C(39)ϪP(4)
O(6)ϪP(6)
Reaction of [Mn2(CO)10] with 1 in THF: 0.66 g (1.22 mmol) of 1
and 0.34 g (1.10 mmol) [Mn2(CO)10] were stirred in about 6 ml
THF for 0.5 h. All material has dissolved and a red solution was
obtained. The 31P NMR spectrum of this solution showed only a
singlet at 20.6 ppm, indicating quantitative formation of the cation
(HC{PPh3}2)ϩ. Layering of the solution with n-pentane produced
a yellow red oil which crystallized to give orange yellow crystals
of 2·THF.
O(5)ϪMn(1)ϪO(6)
O(6)ϪMn(1)ϪO(1)
O(6)ϪMn(1)ϪO(3)
O(5)ϪMn(1)ϪO(4)
O(1)ϪMn(1)ϪO(4)
O(5)ϪMn(1)ϪO(2)
O(1)ϪMn(1)ϪO(2)
O(4)ϪMn(1)ϪO(2)
C(2)ϪO(1)ϪMn(1)
C(2)ϪC(1)ϪP(1)
O(2)ϪC(2)ϪO(1)
O(1)ϪC(2)ϪC(1)
C(40)ϪO(4)ϪMn(1)
P(3)ϪC(39)ϪP(4)
O(4)ϪC(40)ϪC(39)
P(5)ϪO(5)ϪMn(1)
O(5)ϪMn(1)ϪO(1)
O(5)ϪMn(1)ϪO(3)
O(1)ϪMn(1)ϪO(3)
O(6)ϪMn(1)ϪO(4)
O(3)ϪMn(1)ϪO(4)
O(6)ϪMn(1)ϪO(2)
O(3)ϪMn(1)ϪO(2)
C(2)ϪO(1)ϪMn(1)
C(2)ϪC(1)ϪP(2)
P(2)ϪC(1)ϪP(1)
O(2)ϪC(2)ϪC(1)
C(40)ϪO(3)ϪMn(1)
C(40)ϪC(39)ϪP(3)
O(4)ϪC(40)ϪO(3)
O(3)ϪC(40)ϪC(39)
P(6)ϪO(6)ϪMn(1)
113.0(3)
121.3(3)
117.5(3)
88.5(2)
131.2(2)
121.3(3)
150.6(2)
IR (Nujol mull, cmϪ1): 1915 vs, 1896 vs, 1859 vs, 1840 vs, 1480 m, 1439 s,
1341 w, 1312 w, 1236 m, 1184 m, 1161 m, 1101 s, 1074 m, 1057 m, 1032 m,
1017 m, 993 m, 909 m, 804 m, 760 w, 743 m, 720 m, 683 s, 656 s, 559 w,
538 w, 517 w, 494 m.
Reaction of [Mn2(CO)10] with 1 in DME: 0.32 g (0.60 mmol) of 1
and 0.24 g (0.60 mmol) [Mn2(CO)10] were stirred in about 4 ml
DME, which was distilled over potassium prior to use. The re-
sulting suspension (1 is only slightly soluble in DME) was stirred
mechanically at room temperature. After four days all material has
dissolved and an orange solution was obtained. The 31P NMR
spectrum of the solution showed signals (relative intensities in
brackets) at 61.2 (0.23), 46.3 (1.00), 26.0 (2.56), 21.6 (6.20), 20.1
(1.39), 18.8 (1.07), Ϫ3.65 (1.18), and Ϫ10.5 (1.30) ppm. The solu-
tion was layered with n-pentane. After several days yellow needles
separated along with an orange oil. The crystals turned out to be
the salt-like complex 3·1.75DME. The oil was separated and dis-
solved in DME and filtered. In the 31P NMR spectrum of the solu-
tion only a singlet at 21.6 ppm was found. Layering with n-pentane
produced large yellow blocks of 2.
tion [26]. In the reaction of 1 with [Mn2(CO)10] proton ab-
straction proceeds more rapidly from THF than from
DME, and the alternative but slow competitive Wittig reac-
tion becomes important. This is also the case in benzene or
toluene solution but the reaction remains incomplete. If
we assume the formation of [Mn]ǟ1 intermediates in
the first step such as the CO substitution product
[(CO)5Mn(CO)4Mnǟ1] proton abstraction from solvents
becomes plausible but the related protonated complexes
[Mn]ǟ1Hϩ are unstable in this case and decompose with
release of the weak nucleophile (1H)ϩ finally with forma-
tion of 2. Recently, we could show that the cation
(HC{PPh3}2)ϩ is able to serve as a ligand to Agϩ if coordi-
nating anions are absent. Thus, with Ag[BF4] and
(HC{PPh3}2)[BF4] the new trication [Ag(1H)2]3ϩ was pro-
duced [10]. These properties and the insolubility of adducts
of 1 in non polar hydrocarbons limits the scope of synthesis
and characterization.
However, if the reaction pathway is that of a Wittig reac-
tion as with some carbonyl compounds, the formation of
OPPh3 opens the way to the adduct O2Cǟ1 according to
equations 2 and 3 and subsequent formation of complexes
with this ligand. The isolation of the unusual complex 3
from both the polar DME solution and the non polar ben-
zene solution is a hint that this neutral 2:2 ligand combi-
nation of O2CC(PPh3)2 and OPPh3 in 3 is lowest in energy
among others with different ones such as possible 3:0, 1:4,
or 0:6 ligand arrangements.
IR (Nujol mull, cmϪ1) of 2: 1915 sh, 1896 vs, 1859 vs, 1840 vs, 1481 m,
1437 s, 1312 w, 1231 m, 1185 m, 1104 s, 1029 m, 1012 m, 993 s, 744 s, 717 s,
683 vs, 658 vs, 559 s, 533 s, 515 s, 497 s.
Reaction of [Mn2(CO)10] with 1 in benzene: 0.27 g (0.60 mmol)
[Mn2(CO)10] was added to a solution of 0.30 g (0.60 mmol) of 1 in
about 7 ml of dry benzene. Immediately the color of the solution
turned from yellow to orange red. The mixture was stirred magneti-
cally; after about 30 min crystals of unreacted 1, small amounts of
a yellow precipitate, and a red brown oil were detected in the mix-
ture. The mixture was stirred for about ten days at room tempera-
ture. The 31P NMR spectrum of the benzene solution showed
singlets (relative intensities in brackets) at 26.3(1), 20.6(1.2),
Ϫ3.8(2.6), and Ϫ13.0(0.4) ppm; the main signal belongs to unre-
acted 1. The signals at 26.3 and Ϫ13.0 ppm can be assigned to
OPPh3 and a Wittig product of the type [Mn]ϭCϭCϭPPh3. The
mixture was filtered from the precipitate. The filtrate, consisting of
the oil and the benzene solution, was layered with n-pentane. After
about two weeks, yellow orange crystals of 3·4C6H6 have grown
from the oil.
An alternative route, the heterolytic splitting of the Mn-
Mn bond by 1 to produce [(CO)5Mn(C{PPh3}2)][Mn(CO)5]
like the disproportion of [Co2(CO)8] induced by an N-het-
erocyclic carbene (NHC) was not observed [27].
IR (Nujol mull, cmϪ1): 2045 m, 1975 m, 1887 vs, 1851 vs, 1588 m, 1576 m,
1531 m, 1501 m, 1481 s, 1437 s, 1354 m, 1312 w, 1233 w, 1186 m, 1163 w,
1103 s, 1030 w, 995 m, 745 s, 719 s, 683 s, 658 s, 559 w, 544 m, 525 m,
515 m, 502 m.
Z. Anorg. Allg. Chem. 2008, 1415Ϫ1420
© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.zaac.wiley-vch.de
1419

W. Petz, F. Öxler, R. Ronge, B. Neumüller
The nature of the precipitate is still unknown. It is soluble in
CH2Cl2, but in the 31P NMR spectrum only the signal of the cation
(HC{PPh3}2)ϩ was found as a result of the reaction with the sol-
vent.
[11] W. Petz, F. Weller, Z. Naturforsch. 1996, 51b, 1598.
[12] W. Petz, K. Wenck, B. Neumüller, Z. Naturforsch. 2007, 62b,
413.
[13] W. C. Kaska, D. K. Mitchell, R. F. Reichelderfer, J. Or-
ganomet. Chem. 1973, 47, 391.
Reaction of [Mn2(CO)10] with 1 in toluene: 0.87 g (1.63 mmol) of 1
and 0.62 g (1.59 mmol) [Mn2(CO)10] were separately dissolved in
about 5 ml toluene and the solutions were combined; a color
change from yellow to red was observed. The mixture was stirred
for 24 h. The 31P NMR spectrum of the solution showed the signal
of unchanged 1 as the main product; additionally, the signals of
OPPh3 and a Wittig product have appeared in about 1 % of the
main signal.
[14] W. Petz, C. Kutschera, M. Heitbaum, G. Frenking, R. Tonner,
B. Neumüller, Inorg. Chem. 2005, 44, 1263.
[15] a) R. Giordano, E. Sappa, A. Tiripicchio, M. Tiripicchio
Camellini, M. J. Mays, M. P. Brown, Polyhedron 1989, 8, 1855;
b) K. Y. Lee, D. J. Kuchynka, J. K. Kochi, Organometallics
1987, 6, 1886.
[16] Structures with the [Mn(CO)5]Ϫ anion: W. Petz, F. Weller, Z.
Naturforsch. 1991, 46b, 297 and literature therein.
[17] W. Petz, K. Köhler, P. Mörschel, B. Neumüller, Z. Anorg. Allg.
Chem. 2005, 631, 1779.
Acknowledgement. We thank the Deutsche Forschungsgemeinschaft
for financial support. W. P. is also grateful to the Max-Planck-
Society, Munich, Germany, for supporting this research project.
[18] W. Petz, A. Brand, F. Öxler, B. Neumüller, Z. Anorg. Allg.
Chem. 2006, 632, 588.
[19] Salts with the cation (HC{PPh3}2)ϩ: a) Ref. [5] and [12] and
literature therein; b) W. Petz, C. Kutschera, B. Neumüller,
Organometallics 2005, 24, 5038; c) W. Petz, F. Öxler, B.
Neumüller, Z. Anorg. Allg. Chem. 2008, 634, 223.
[20] For other MnII compounds with the OPPh3 ligand see: Gmelin
Handbook of Inorganic and Organometallic Chemistry, Mn
Main Vol. D 8, Springer-Verlag Berlin, Heidelberg, Yew York,
London, Paris, Tokyo 1990.
Crystallographic data for the structures have been deposited with the
Cambridge Crystallographic Data Center, 12 Union Road, Cam-
bridge CB21EZ. Copies of the data can be obtained on quoting the
depository numbers CCDC 682167 (2), CCDC 682168 (2·THF),
CCDC 682169 (3·1.75DME), and CCDC 682170 (3·4C6H6). (Fax:
(ϩ44)1223-336-033; E-mail: deposit@ccdc.cam.ac.uk).
[21] a) G. Ruban, V. Zabel, Cryst. Struct. Commun. 1976, 5, 671;
b) G. Bandoli, G. Bortolozzo, D. A. Clemente, U. Croatto, C.
Panattoni, J. Chem. Soc. A, 1970, 2778.
[22] K. Komita, Acta Crystallogr. 1985, C41, 1832.
[23] N. Burford, R. E. v. H. Spence, A. Linden, T. S. Cameron,
Acta Crystallogr. Cryst. Struct. Commun. 1990, C46, 92.
[24] N. Burford, B. W. Royan, R. E. v. H. Spence, T. S. Cameron,
A. Linden, R. D. Rogers, J. Chem. Soc. Dalton Trans. 1990,
1521.
[25] G. Frenking, R. Tonner, pers. communication.
[26] W. Petz, unpublished results.
[27] H. van Rensburg, R. P. Tooze, D. F. Foster, S. Otto, Inorg.
Chem. 2007, 46, 1963.
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Z. Anorg. Allg. Chem. 2008, 1415Ϫ1420