Fixation of metallo nitrile ylides and metallo nitrile imines as ligands in transition metal complexes [1]

Article abstract of DOI:10.1002/zaac.200900531

1,3-Dipoles of the type metallo nitrile ylide and metallo nitrile imine were prepared by mono-a-deprotonation of CH-acidic {[W(CO)₅CHCH ₂PPh₃]PF₆, M(CO)₅CNCH ₂CO₂A (M = Cr, W; R = Me, Et), [Pt(Cl)(CNCH ₂CO₂Et)(PPh₃)₂]BF₄} and NH-acidic isocyanide complexes (Cr(CO)₅CNNH₂) and were stabilized by coordination to a second transition metal complex fragment (Cr(CO)₅, [M(CO)₅]⁺ (M= Mn, Re), [FeCp(CO) ₂]⁺, [Pt(Cl)(PR₃)₂]⁺ (R = Et, Ph)}. All dinuclear products 1-7, 10, and 11 are neutral species except [(Ph₃P)₂(Cl)Pt{μ₂-CNCH(CO ₂Et)}Pt(Cl)(PPh₃)₂]BF₄ (8). Complex (OC)₅W{μ₂-CNCH(CO₂Et)}Pt(Cl)(PEt ₃)₂ (5b) was characterized by X-ray diffraction. Twofold deprotonation/platination to give (OC)₅Cr(μ₃-CNC(Ph)} [Pt(Cl)(PPh₃)₂]₂ (9) was achieved, in the case of Cr(CO)₅CNCH₂Ph.

Full text of DOI:10.1002/zaac.200900531

ARTICLE
DOI: 10.1002/zaac.200900531
Fixation of Metallo Nitrile Ylides and Metallo Nitrile Imines as Ligands in
Transition Metal Complexes [1]
Alfons Völkl,[a,b] Dagobert Achatz,[a] Friedrich Schoder,[a] Gerhard Zinner,[a,b]
Heribert Stolzenberg,[a,b][‡] Wolfgang Beck,[c] and Wolf Peter Fehlhammer*[b,c]
Keywords: Ylides; Imines; Stabilization by coordination; Chromium; Tungsten
Abstract. 1,3-Dipoles of the type metallo nitrile ylide and metallo ni- clear products 1–7, 10, and 11 are neutral species except
trile imine were prepared by mono-α-deprotonation of CH-acidic [(Ph3P)2(Cl)Pt{μ2-CNCH(CO2Et)}Pt(Cl)(PPh3)2]BF4 (8). Complex
{[W(CO)5CHCH2PPh3]PF6, M(CO)5CNCH2CO2R (M = Cr, W; R = (OC)5W{μ2-CNCH(CO2Et)}Pt(Cl)(PEt3)2 (5b) was characterized by
Me, Et), [Pt(Cl)(CNCH2CO2Et)(PPh3)2]BF4} and NH-acidic isocya- X-ray diffraction. Twofold deprotonation/platination to give
nide complexes (Cr(CO)5CNNH2) and were stabilized by coordination (OC)5Cr{μ3-CNC(Ph)}[Pt(Cl)(PPh3)2]2 (9) was achieved in the case of
to a second transition metal complex fragment {Cr(CO)5, [M(CO)5]+ Cr(CO)5CNCH2Ph.
(M = Mn, Re), [FeCp(CO)2]+, [Pt(Cl)(PR3)2]+ (R = Et, Ph)}. All dinu-
dinated α-CH- and -NH-acidic functional isocyanides. In no
Introduction
Organic 1,3-dipoles of the nitrile ylide and nitrile imine type
case, however, we were able to isolate the salt-like species
cat+[M{C≡N+–X–}(CO)5]– (cat+ = alkali or ammonium cation;
as a rule are unstable species eluding isolation [2]. Even so,
X = CHR, NH) as a pure substance, nor could we get hold of
their generation in the presence of a dipolarophile as reaction
neutral complexes such as [Pt{C≡N+–C–HR}(Cl)(PPh3)2] (R =
partner has led to a rich [3+2]-cycloaddition chemistry, which
CO2Et) [11]. Still, it proved sufficient to run their [3+2]-cy-
is inseparably bound up with the name of Huisgen [3]. How-
cloaddition reactions with dipolarophiles “in situ”, just like
ever, using the right set of substituents, stable variants of both
with the purely organic derivatives. Stable variants of C, which
nitrilium betaïns such as A or B could be obtained [2c, 4, 5].
+
carry a PPh3 group at the trivalent carbon (E) could be ob-
There is a review on stable nitrile imines [5b], and there are
tained starting from a triphenylphosphonio-substituted methy-
reports on the parent species HC≡N+–C–H2 and H–C≡N+–N–H,
lisocyanide [9c, 9d, 12]. With some reservation – the primary
which display a surprising stability in the gas phase [6, 7].
cycloaddition product lacks the possibility of stabilization
An overall view of their chemical ambience, derivation and
through H+ migration – the same applies to F [13].
interrelations also with isocyanides and isocyanide complexes
has been presented recently [8].
Essentially the same picture can be painted in the case of
metallo nitrile ylides C and imines D. In these organometallic
versions of 1,3-dipoles, which have been studied by us for
many years, the organyl substituent at the divalent carbon is
replaced by a metal (or metalloid) complex fragment [9, 10].
Both, metallo nitrile ylides and metallo nitrile imines are basi-
cally accessible by deprotonation of the respective metal-coor-
* Prof. Dr. W. P. Fehlhammer
E-Mail: wpfehlhammer@gmx.de
[a] Institut für Anorganische Chemie
Friedrich-Alexander-Universität Erlangen-Nürnberg
Egerlandstr. 1
91058 Erlangen, Germany
[b] Institut für Anorganische und Analytische Chemie
Freie Universität Berlin
Fabeckstr.
14195 Berlin, Germany
[c] Department Chemie und Biochemie
Ludwig-Maximilians-Universität München
Butenandtstr. 5–13
81377 München, Germany
[‡] X-ray structure determinations
Z. Anorg. Allg. Chem. 2010, 636, 1339–1346
© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
1339

W. P. Fehlhammer et al.
ARTICLE
In this paper we report on the stabilization of the organome- 2. Stabilization of Metallo Nitrile Ylides by Coordination to
tallic 1,3-dipoles by coordination to a second transition metal a Second Transition Metal
by the markedly negative α-C respectively α-N ends of the
deprotonated functional isocyanides ethyl isocyanoacetate and
isodiazomethane.
To the best of our knowledge no attempts to stabilize organic
nitrile ylides or nitrile imines by metal coordination have so
far been made.
Early
attempts
to
deprotonate
the
complexes
M(CO)5CNCHPh2 (M = Cr, W) with stoichiometric amounts
of LinBu or NaH in tetrahydrofuran at low temperatures
(–78 °C) led to yellow salt-like solids, which were insoluble
in organic media. The IR spectra of the partly pyrophoric pro-
ducts displayed marginally shifted but definitely weaker ν(CN)
bands (≈ 2190 m cm–1) and lower ν(CO) frequencies indicative
of anionic carbonyl complexes. The same reaction with
KOtBu, on the other hand, gave a product whose IR spectrum
showed no ν(CN) absorption at all [24a]. More promising
was the reaction of W(CO)5CNCH2SO2-p-tolyl with
Na[N(SiMe3)2] in toluene at –20 °C. The white precipitate
turned out to be soluble in water and THF, showed the required
IR spectroscopic data and even analyzed correctly (Experimen-
tal Section) [24a, 24b]. Still, what all these products have in
common is their non-reversibility to the starting materials by
protonation with aqueous HCl or HCl-gas in organic media. In
view of these findings the assignment of the IR spectroscopic
features between 2150 and 2200 cm–1 to ν(CN) vibrations ap-
pears questionable.
Results and Discussion
1. Isocyanomethylenephosphorane as a C,C'-Bridging Li-
gand between W(CO)5 and Cr(CO)5 Entities
(OC)5M––C≡N+–C–(H)P+Ph3 (M = Cr, W) proved to be the
first stable metallo nitrile ylides just like CN–C–H–P+Ph3 was
the first stable α-carbanionic (or deprotonated, respectively,
metalated) isocyanide [9c, 12]. The reaction of the tungsten
complex with Cr(CO)5THF to give 1 was studied with the ob-
jective to learn about its coordination potential through the yl-
idic carbon atom. Numerous transition metal complexes of P-
ylides have been described; due to the stabilizing effect of
metal coordination one could even get hold of several reactive
intermediates [14–19]. In solution, however, these complexes
turn out to be rather unstable reverting to the components and
further degradation products [20, 21]. This behavior is also
shown by 1, which in THF or CH2Cl2 mainly suffers hydroly-
sis to give W(CO)5CNMe and triphenylphosphane oxide. Two
sets of the ν(CO) band pattern characteristic of M(CO)5 com-
plex fragments appear in the IR, which were assigned to the
tungsten (2065 s [A1], 1924 vs. cm–1 [E]) and chromium part
(2052 s [A1], 1874 vs. cm–1 [E]) by comparison with
[W(CO)5CNCH2PPh3]PF6 and literature data for M(CO)5/P-yl-
ide complexes [19]. Metal coordination of the ylidic carbon
atom causes the ν(CN) frequency to shoot up almost as high
as the values of the protonated forms [CNCH2PPh3]PF6 (2149
s cm–1) and [W(CO)5CNCH2PPh3]PF6 (2161 s cm–1), which
lie ca. 90 cm–1 or, respectively, 62 cm–1, above those of the
ylides CNCHPPh3 and W(CO)5CNCHPPh3. Contrary to occa-
sional comments the presence or absence of a lone pair at the
α atom obviously has quite a strong effect on the ν(CN) fre-
quency, a conclusion of particular relevance for the N-isocya-
nide chemistry [22]. A similar though completely expected
course is taken by the chemical shift of the methin or, respec-
Note, however, that our studies of [3+2] cycloadditions with
metallo nitrile ylides were carried out with solutions containing
low stationary concentrations of the 1,3-dipoles. These solu-
tions were prepared from M(CO)5CNCH2R (M = Cr, W;
R = CO2Me, CO2Et, SO2-p-tolyl) and stoichiometric amounts
of LinBu, NaH or NEt3 in THF at low temperatures showing
no sign of decomposition (see below and literature [9b, 25]).
As early as 1968, a first triphenylborio nitrile ylide – Li[Ph3B–
CNCPh2] – similarly described as “shortly stable in solution”
had been reported by Hesse and co-workers [26]. Also note
that the action of Na[N(SiMe3)2] (or of other typical bases)
on M(CO)5CNCH2CO2Et (M = Cr, W) came up with a cleav-
age of the ester group thereby opening a synthetic access to
isocyanoacetato complexes [27]. A totally different course –
transformation of a cis-CO into a CN– ligand to give
Na[M(CN)(CO)4CNCy] – is taken by the reaction between
Na[N(SiMe3)2] and M(CO)5CNCy (M = Cr, W) [24c].
Partial success was eventually achieved by treatment of a
solution of Li[W(CO)5CNCHCO2Et] with MnBr(CO)5.
Though available only in low yield and not analytically pure,
the yellow crystalline product is formulated as compound 2
mainly on the basis of the mass spectrum, which shows the
molecular peak followed by a series of lines arising from the
successive loss of CO. In the IR spectrum, expectedly, the
W(CO)5CNCHCO2Et part appears practically unchanged,
whereas the ν(CO) bands of the Mn(CO)5 group partially expe-
rience a considerable shift to lower wavenumbers (Experimen-
tal Section). The reaction of the same tungstenio nitrile ylide
with equimolar amounts of ReBr(CO)5 at –78 °C only brought
gradual improvements: the structure of the yellow amorphous
1
tively, methylene proton in the H NMR spectrum, viz. from
2
2
5.32 (d, JPH = 10 Hz, [CNCH2PPh3]PF6) to 2.99 (d, JPH
=
2
28.5 Hz, CNCHPPh3) to 5.25 (d, JPH = 8 Hz, 1) (see Experi-
mental Section) [23].
1
product 3 is confirmed by its IR, H-NMR and, particularly,
mass spectrum containing the full set of expected lines; still,
varying analyses point to an easy decomposition of the com-
pound. Further experiments with the chloro complexes
1340
www.zaac.wiley-vch.de
© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2010, 1339–1346

Metallo Nitrile Ylides and Metallo Nitrile Imines as Ligands [1]
Mn(Cl)(CO)5 and Re(Cl)(CO)5 did not bring forth any substan- (P2), respectively, are known to inversely reflect the different
tial results.
trans-influence Cl < ‘C'-ligand, a 1:1 assignment δ-value/P
atom is reached (Figure 1 and Experimental Section) [28]. The
1H NMR spectra of 5a,b are dominated by two broad multip-
lets between 1.0 and 2.5 ppm arising from the PEt3 protons;
the mainly interesting α-CH signals, though of exceedingly
low intensity, correspond in all details with the postulated
structure by showing the typical form of the X part of an ABX
spin system, viz. two doublets of equal intensity plus platinum
satellites. The two (P, H)-coupling constants agree perfectly
with those found for [Pt(Me)(NO3)dppe] (dppe = 1,2-bis(di-
phenylphosphanyl)ethane) or cis-[Pt(Cl)(CH2CN)(PPh3)2],
which served for comparison [29, 30]. Following these works
The first stable complex of the labile species “metallo nitrile
ylide” 4 has been obtained from Li[W(CO)5CNCHCO2Et] and
Fe(Cl)Cp(CO)2 and structurally identified by the usual spectro-
scopic methods (Experimental Section). It forms orange crys-
tals, which even melt without decomposition (!). Other stable
complexes resulted from the reaction of stoichiometric
amounts of pentacarbonyl(carbethoxymethylisocyanide)chro-
mium and -tungsten with n-butyllithium and cis-dichloro-
bis(triethylphosphane)platinum. Simple recrystallization af-
forded colorless crystals of 5a and 5b, which analyzed
correctly and turned out to be of sufficient quality for X-ray
diffraction studies (cf. 3.). The IR spectra combine the charac-
teristic band patterns of both complex components of which
only the ν(CO2)ester absorptions show a remarkable downshift
of 30 cm–1 as compared with the parent isocyanide complexes
indicating a residual carbanionic nature of the newly platinum-
bonded α-C-atom. More structure-relevant data are provided
by NMR spectroscopy. Thus 5b gives rise to two 31P NMR
signals at δ = –10.1 (P1) and –6.6 (P2) with pairs of satellites
3
the higher J(31P, H) has been assigned to the coupling with
the trans-P-ligand. The (195Pt, H) coupling constant could only
be determined for 5a; with a value of 87.2 Hz 5a unequivo-
cally belongs to the class of cis-configured complexes of the
type PtX(Me)(PPh3)2 (X = Cl, Br, N3, NCS, NO2). For the
2
trans-isomers the J(195Pt, H) amount to > 105 Hz, again a
consequence of the weaker trans influence (trans effect) of X
as against P, which strengthens the (195Pt, H)-coupling [31].
indicating nonequivalent phosphorus atoms, i.e.,
a cis-
Pt(PEt3)2 arrangement. Moreover, since the markedly different
1J(195Pt, 31P) coupling constants of 2231 (P1) and 3838 Hz
Further platinum-stabilized chromio- and tungstenio nitrile
ylides (6, 7) have been obtained in good yield by reaction of
M(CO)5CNCH2CO2R (M = Cr, W; R = Et, Me) with the
chloro-bridged
dinuclear
dication
[(Ph3P)2Pt(μ-Cl)2-
Pt(PPh3)2](BF4)2 in the presence of LinBu. In their characteris-
tic features the IR spectra of course are very similar to those
of 5. An additional strong band at 550 cm–1 in the spectrum
of 6 suggests cis-configuration of the bis(triphenylphos-
phane)platinum unit [32]. At first glance this seems inconsist-
ent with the 31P-NMR spectrum showing only one singlet
though with two sets of platinum satellites. Obviously an acci-
dental coincidence of the non-equivalent cis-positioned phos-
phorus nuclei has to be assumed. The most interesting
1H-NMR signal, that of the α-CH proton, is partly hidden un-
der the quartet of the ester group; mainly for this reason we
Figure 1. ORTEP plot and labelling scheme of complex 5b. Ethyl hy-
drogen atoms are omitted for clarity and the thermal ellipsoids are
drawn at the 30 % probability level. Selected bond lengths /Å and
angles /°:W–C2 2.11(3), W–C3 1.96(3), (W–COcis av. 2.015, C2–N
)
1.12(3), N–C1 1.43(4), C1–H1 0.96(6), C1–C8 1.48(3), C8–O2
1.22(3), C8–O1 1.31(3), O1–C9 1.46(3), Pt–C1 2.16(2), Pt–Cl
2.363(6), Pt–P1 2.313(7), Pt–P2 2.248(5);W–C2–N 177(2), C2–N–C1
172(2), N–C1–C8 114(2), N–C1–Pt 109(1), C1–C8–O2 123(3), C1–
C8–O1 113(2), O2–C8–O1 124(2), C1–Pt–Cl 84.2(5), C1–Pt–P2
87.0(5), P1–Pt–P2 104.6(2), P1–Pt–Cl 84.2(2).
Z. Anorg. Allg. Chem. 2010, 1339–1346
© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.zaac.wiley-vch.de
1341

W. P. Fehlhammer et al.
ARTICLE
also synthesized 7a,b. Unfortunately, this time the α-CH pro-
ton signal coincided with that for methyl and THF, which was
contained in the crystal (Experimental Section).
With the synthesis of 8 from trans-[Pt(Cl)(CNCH2CO2Et)-
(PPh3)2]BF4, KOtBu and [(Ph3P)2Pt(μ-Cl)2Pt(PPh3)2](BF4)2 a
first platinio nitrile ylide could be stabilized by coordination
to platinum. The salt-like stable product, which crystallizes in
large rods can also be described as an α-deprotonated carbe-
thoxymethyl isocyanide C,C'-bridging two platinum complex
fragments. Its low solubility did not allow to obtain instructive
NMR spectra; in the IR ν(CO2Et) as well as ν(CN) appear
somewhat shifted to lower wavenumbers.
Benzylisocyanide complexes had proven unreactive as re-
gards [3+2] cycloadditions. So it was surprising that
Cr(CO)5CNCH2Ph reacted with [(Ph3P)2Pt(μ-Cl)2Pt(PPh3)2]-
(BF4)2 in the presence of a mixture of LinBu and NaH (1:1)
to give a powdery product, which according to the IR spectrum
contained both complex reactants suggesting α-platination had
taken place. The elemental analysis of the colorless fraction,
which was obtained after repeated recrystallization however
points to a doubly platinated product 9, which needs further
3. X-ray Structure of 5b
The crystal lattice of 5b is made up of discrete molecules
with the expected primary structure, which combines that of a
functionalized (α-metallated) methylisocyanide coordinated to
W(CO)5 with that of a chlorobis(triethylphosphane)plati-
num(II) complex carrying a functionalized methyl ligand (Fig-
ure 1). Special areas of interest are
- The stereochemistry of the coordination sphere of tungsten
whose W–CO bonds of varying length – d(W–C(O)ax)
[1.96(3) Å] is markedly shorter than the average bond between
.
W
and the equatorial CO ligands [d(W–C(O)eq)av
=
2.02(2) Å] – reflect the donor capacities of a typical C-isocya-
investigation. In this context van Leusen's claim of α-dilithi- nide. At the same time this ligand gives rise to the longest
tungsten to carbon bond in 5b [d(W–C2) = 2.11(3) Å] and a
practically linear W–C2–N arrangement [177(2)°], totally in
line with the accumulated data on other carbonyl/isocyanide
tungsten complexes [36].
ated tosylmethylisocyanide – CN–CLi2–SO2–p-tolyl – as an
isolable intermediate as well as our “permetallated methyliso-
cyanide” (OC)5Cr–C≡N–C≡[Co3(CO)9] deserves mentioning
[33, 34].
- The stereochemistry about platinum, which is planar – the
X–Pt–Y angles add up to exactly 360.0° – but not at all square:
the P1–Pt–P2 angle [104.6(2)°] formed by the cis-Pt(PEt3)2
group is almost 20° larger than the average of the other three
(85.1°), and the platinum to P2 bond trans to Cl [2.248(5) Å]
is considerably shorter than Pt–P1 [2.313(7) Å] trans to the
functionalized methyl ligand though both values still corre-
spond with the order of Pt–P bond lengths generally found in
(phosphane)platinum(II)
complexes
[37–40].
Since
1J(195Pt,31P)-coupling constants logically decrease with in-
creasing Pt–P bond lengths and vice versa our assignment of
1
the smaller J(Pt,P) value to P1 reached above thus is con-
firmed. The Pt–Cl bond length [2.363(6) Å] is in the normal
range [41, 42], whereas the platinum to carbon bond
[2.16(2) Å] is markedly longer than calculated from the cova-
lent radii (2.08 Å) and also longer than the Pt–C bonds in
trans-[Pt(Cl)(R)(phosphane)2] {R = CH2CN, phosphane =
PPh3: d(Pt–C) = 2.08(1) Å [43]; R = Me, phosphane =
PMePh2: d(Pt–C) = 2.081(6) Å [44]}. The Pt–C bond length in
trans-Pt(CH2CN)(H)(PPh3)2 of 2.16(1) Å, on the other hand,
seems to suggest comparable trans-influences for the PEt3 and
hydrido ligands [45] (Figure 1).
- The ascertained arrangement of a (coordinated) metallo ni-
trile ylide in comparison with the one calculated for the (free)
organic analogue [46]. Whereas both C–N–C skeletons are
slightly bent at the nitrogen atom, a fundamental difference
between these 1,3-dipoles exists in their reversed polarities,
i.e., the carbanionic center, which resides at the divalent carbon
atom C1 in organic systems passes on to the trivalent carbon
atom C2 in metallo derivatives (H, I). Under the influence of
the electron-rich metal (W0), which stabilizes carbenium spe-
Above we could demonstrate that metallo nitrile ylides, or,
which is the same, α-deprotonated isocyanide complexes coor-
dinate to transition metals through the trivalent carbon repre-
senting the negative end of the 1,3-dipole or, respectively, the
α-carbanion. In most cases the gain in stability was sufficient
to allow the dinuclear products to be isolated and stored over
prolonged periods. This kind of fixation of labile intermediates
might well play a decisive role in catalytic processes. An ex-
ample is the Cu2O-catalyzed cycloaddition of unsaturated es-
ters and nitriles to α-CH–acidic isocyanides, which Saegusa
postulated to proceed via complex G [35]. Extensions to in-
clude 1,3-dipoles seem appropriate. We have not investigated
the availability of the stabilized metallo nitrile ylides for [3+2]
cycloadditions, however.
1342
www.zaac.wiley-vch.de
© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2010, 1339–1346

Metallo Nitrile Ylides and Metallo Nitrile Imines as Ligands [1]
cies, the allenyl anion-type resonance formula H with two C=
N double bonds already loses most of its significance in favor
of the more asymmetric propargyl (here: classical isocyanide
complex) form I; coordination to a second metal (PtII) through
C2 then causes a further shortening of the C1–N and lengthen-
ing of the N–C2 bond to end up with the established C-isocya-
nide complex structure.
Experimental Section
General Remarks: All experiments were performed under argon in
dried argon-saturated solvents. [W(CO)5CNCH2PPh3]PF6 [12],
W(CO)5CNCH2SO2-p-tolyl
Cr(CO)5CNCH2CO2Et
[9b],
[25],
Cr(CO)5CNCH2Ph
W(CO)5CNCH2CO2Et
[9b],
[25],
Cr(CO)5CNNH2 [13, 48], [Re(CO)6]PF6 [49], [FeCp(CO)2CS]PF6 [50,
51], [FeCp(CO)(CNPh)2]PF6 [51], and [FeCp(CNPh)3]Cl [51, 52] were
prepared according to literature procedures.
IR spectra were recorded with a Zeiss IMR 16 and IRM 25, Perkin–
Elmer Mod. 621, and Beckman IR 12 spectrometers, NMR spectra
with a Jeol JNM-PMX-60 or a Jeol JNM-PS-100. Mass spectra were
recorded with a Varian CH-5 (excitation energy 70 eV). Microanalyses
(C, H, N) were obtained with a Heraeus CHN Rapid-Elementanalysa-
tor. Melting or decomposition points were determined with a Büchi
Modell 510 melting point apparatus and are uncorrected.
4. Stabilization of Metallo Nitrile Imines by Coordination to
a Second Transition Metal
Syntheses
Preparation and stabilization of the second type organometal-
lic analogue of Huisgen's “organic” 1,3-dipoles, the chromio
nitrile imine [(OC)5CrC≡N+–N–H]–, closely followed the
method established for metallo nitrile ylides [47]. Deprotona-
tion of the parent pentacarbonyl(isodiazomethane)chromium
occurred with triethylamine in fourfold excess to generate a
low concentration of the 1,3-dipole, which was immediately
treated with the Lewis-acidic metal complexes FeCp(Cl)(CO)2
and [Pt(μ-Cl)(PPh3)2]2(BF4)2 to give the moderately stable pro-
ducts 10 and 11 the latter of which is reasonably well charac-
μ-{Isocyanomethylenetriphenylphosphorane-C,C'}pentacarbonyl-
tungsten-pentacarbonylchromium (1): A solution of Cr(CO)5THF
prepared by photolysis of hexacarbonylchromium (0.70 g, 3.18 mmol)
in tetrahydrofuran (200 mL) as described in the literature [53] was
reduced to about half its volume and combined with a solution of
W(CO)5CNCHPPh3 prepared from [W(CO)5CNCH2PPh3]PF6 (2.14 g,
2.5 mmol) and NaNH2 (3.0 g, 75 mmol) in toluene (150 mL) accord-
ing to a procedure published earlier [9d]. After stirring for 4 h at 0 °C
the solvent, excess Cr(CO)6, and possibly formed W(CO)5CNMe were
removed in high vacuum at 25–30 °C. The residue was dissolved in
CH2Cl2 (ca. 20 mL) and the solution was filtered and layered with two
times the volume of petroleum ether. At –15 °C compound 1 separated
as yellow microcrystals (m.p. 138 °C, dec.), which were slightly solu-
ble in ethyl ether and soluble in polar solvents such as CH2Cl2 or
acetone. There, however, slow decomposition took place. Yield 0.84 g
(41 % rel. to [W(CO)5CNCH2PPh3]PF6). C30H16CrNO10PW (817.28):
calcd. C 44.09, H 1.97, N 1.71 %; found C 43.54, H 2.20, N 2.48 %.
1
terized by IR and H NMR spectroscopy and elemental analy-
sis (Experimental Section).
IR (KBr): ν = 2143 s [ν(CN)]; 2065 s, 2052 s, 1924 vs, 1874 vs.
˜
1
[ν(CO)] cm–1. IR (CH Cl ): ν = 2062 s, 2050 s [ν(CO)-A ] cm–1. H
˜
2
2
1
NMR (60 MHz, CD3CN): δ = 7.8 (m, CHarom., 15 H); 5.25 (d, JPH
=
8 Hz, 1 H). 31P NMR (90 MHz, CH2Cl2): δ = 31.7 ppm.
Conclusion
Attempted Isolation of the 1,3-Dipole Na[W(CNCHSO2-p-
tolyl)(CO)5]: A solution of Na[N(SiMe3)2] (0.17 g, 0.93 mmol) in tol-
uene (30 mL) was filtered through sea sand, cooled to –30 °C and
added to a solution of W(CO)5CNCH2SO2-p-tolyl (0.48 g, 0.93 mmol)
in toluene (50 mL). After 40 min the colorless precipitate was filtered
off through a cooled frit (–20 °C), washed thoroughly with cold tolu-
ene and petroleum ether and dried in high vacuum. On warming to
room temperature no changes could be observed. The substance was
easily soluble in THF and water; in the latter it soon came to clouding,
however. Yield 0.375 g (75 %). C14H8NaNO7SW (541.12): calcd. C
31.07, H 1.49, N 2.59 %; found C 30.36, H 1.87, N 2.56 %.
α-Deprotonated C- and N-isocyanide complexes represent
true organometallic analogues of Huisgen's “organic” 1,3-di-
poles, nitrile ylides, and nitrile imines, respectively, as is
clearly evident from their [3+2]-cycloaddition chemistry [8–
10]. With the exception of M(CO)5CNCHPPh3 (M = Cr, W),
which are stable substances due to the presence of the carban-
ion-stabilizing phosphonio substituent, all other studied met-
allo nitrile ylides and metallo nitrile imines only exist as short-
lived intermediates generated and reacted “in situ”. “Stabiliza-
tion by coordination” to an appropriate second transition metal
now proved to be the method of choice to get hold of these
interesting species. Best results were achieved with cationic
platinum complex fragments in accord with the well-known
ability of this metal to form particularly stable metal–carbon
bonds. The most striking consequence of the fixation of the
chromio and tungstenio nitrile ylides as ligands in platinum(II)
[and iron(II)] complexes perhaps is that the products 4–7 even
melt without decomposition.
(OC)5W{μ-CNCH(CO2Et)}Mn(CO)5
(2):
A
solution
of
W(CO)5CNCH2CO2Et (0.775 g, 1.77 mmol) in THF (70 mL) was
dried with Li[AlH4] and cooled to –78 °C. After addition of LinBu
(1.2 mL of a 1.6 m solution in n-hexane) stirring was continued for
30 min. during which a colorless product precipitated. Afterwards, a
solution of MnBr(CO)5 (0.487 g, 1.77 mmol) in THF (50 mL), also
cooled to –78 °C, was added dropwise, and the mixture was stirred for
another 2 h at low temperature. It was allowed to gradually warm to
room temperature, then the solvent was removed and the residue dis-
Z. Anorg. Allg. Chem. 2010, 1339–1346
© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.zaac.wiley-vch.de
1343

W. P. Fehlhammer et al.
solved in benzene. The solution was filtered, and the product was pre- [νas(CO2)ester]; 1188 s [νs(CO2)ester] cm–1. IR (CH Cl ): ν = 2180 s
ARTICLE
˜
2
2
cipitated with petroleum ether. Repeated recrystallization from dichlo- [ν(CN)]; 2060 s, 1985 sh, 1940 vs. [ν(CO)]; 1720 s [νas(CO2)ester];
romethane/n-pentane and benzene/n-pentane gave
yellow 1195 s [νs(CO2)ester] cm–1. 31P{1H} NMR (60 MHz, CD2Cl2): δ = –
microcrystalline compound in low yield. IR (CHCl ): ν = 2179 m 10.1 (s + sat., P1, JPtP1 = 2231 Hz), –6.6 (s + sat., P2, JPtP2
a
1
1
=
˜
3
[ν(CN)]; 2069 m, 2045 m, 2012 s, 1950 vs. [ν(CO)]; 1750 m 3838 Hz). 1H NMR (60 MHz, CDCl3): δ = 4.69 (dd + sat., CNCH,
[νas(CO2)ester] cm–1. For comparison, IR [W(CO)5CNCH2CO2Et/ 3JP1H = 10.2 Hz; JP2H = 6.4 Hz; JPtH = 87.2 Hz, 1 H), 4.24 (q, CH2-
3
2
CHCl ]: ν = 2178 m [ν(CN)]; 2065 m, 1975 sh, 1948 vs. [ν(CO)] cm–1. ester, JHH = 7.0 Hz, 2 H), 2.5–1.7 (m, CH2-phosphane, 12 H), 1.7–
3
˜
3
IR [MnBr(CO) / CCl ]: ν = 2133 w, 2050 s, 2019 w, 2001 m 1.0 (m, CH3-phosphane + CH3-ester, 21 H).
˜
5
4
[ν(CO)] cm–1 [54].
(OC)5W{μ-CNCH(CO2Et)}Pt(Cl)(PEt3)2 (5b): The complex was
prepared from W(CO)5CNCH2CO2Et (900 mg, 2.06 mmol), LinBu
(132 mg, 2.06 mmol) (15 % solution in n-hexane), and cis-
PtCl2(PEt3)2 (1.035 g, 2.06 mmol) as described for 5a. Yield 1.36 g
(73 %), m.p. 127 °C. C22H36NO7ClP2PtW (902.88): calcd. C 29.27, H
(OC)5W{μ-CNCH(CO2Et)}Re(CO)5
(3):
A
solution
of
W(CO)5CNCH2CO2Et (0.31 g, 0.71 mmol) in THF (30 mL) was
cooled to –78 °C. To this an equimolar amount of LinBu (15 % solu-
tion in n-hexane) was added dropwise. After 30 min the reaction was
complete. Afterwards, ReBr(CO)5 (0.29 g, 0.7 mmol) was added, and
the mixture was allowed to warm to room temperature. The solvents
were removed, and the residue was extracted with 3 × 20 mL of ethyl
ether. By addition of n-hexane compound 3 could be precipitated from
the orange ethereal solution as yellow powder. Yield 0.36 g (67 %).
4.02, N 1.55 %; found C 29.38, H 4.27, N 1.50 %. IR (KBr): ν = 2180
˜
s [ν(CN)]; 2063 s, 1989 s, 1930 vs,b, 1900 vs. [ν(CO)]; 1726 sh, 1721
s [νas(CO2)ester]; 1185 s [νs(CO2)ester] cm–1. IR (CH Cl ): ν = 2180 s
˜
2
2
[ν(CN)]; 2060 s, 1990 sh, 1940 vs. [ν(CO)]; 1720 s [νas(CO2)ester];
1190 s [νs(CO2)ester] cm–1. H NMR (60 MHz, CDCl3): δ = 4.61 (dd
1
3
3
2
IR (KBr): ν = 2180 w [ν(CN)]; 2102 w, 2082 m, 2048 s, 1920 vs.
˜
+ sat., CNCH, JP1H = 10.8 Hz; JP2H = 6.4 Hz; JPtH = not obsvd., 1
[ν(CO)]; 1718 m [νas(CO2)ester] cm–1. 1H NMR (60 MHz, CDCl3): δ =
3
H), 4.17 (q, CH2-ester, JHH = 7.0 Hz, 2 H), 2.6–1.7 (m, CH2-phos-
3
4.47 + 4.36 (s, CH + q, CH2, 3 H), 1.44 (t, Me, JHH = 7.2 Hz, 3 H).
phane, 12 H), 1.7–0.9 (m, CH3-phosphane + CH3-ester, 21 H).
MS (EI, 70 eV, 130 °C): m/z = 762 (32) [M]+; 734 (5), 706 (26), 678
(21), 650 (36), 622 (38), 594 (68), 566 (56), 538 (65), 510 (31), 482
(24) [M – n(CO)]+ (n = 1–10); 438 (100) [M –W(CO)5]+; 436 [M –
Re(CO)5]+.
(OC)5Cr{μ-CNCH(CO2Et)}Pt(Cl)(PPh3)2 (6):
A
solution of
Cr(CO)5CNCH2CO2Et (591 mg, 1.94 mmol) in THF (30 mL) was
cooled to –65 °C. To this LinBu (124 mg, 1.94 mmol) (15 % solution
in n-hexane) and a suspension of [PtCl(PPh3)2]2(BF4)2 (1.632 g,
0.97 mmol) in THF (10 mL) were added. Stirring was continued for
5 h during which the mixture was allowed to warm to room tempera-
ture. By now a dark yellow solution had formed and a colorless solid
was suspended, which was collected on a frit and recrystallized from
THF/petroleum ether to give a mixture of needle- and cube-shaped
colorless crystals. A further crop of crystals could be obtained by layer-
ing the filtrate with petroleum ether. Overall yield 1.87 g (91 %). The
compound began to melt at 144 °C, but solidified again forming yel-
low needles at ≈ 163 °C; at 193 % it decomposed leaving a clear red
melt. C46H36NO7ClCrP2Pt [calcd. 1058.90; found (osmom. in CH2Cl2)
1068]: calcd. C 52.18, H 3.43, N 1.32, Cl 3.35 %; found C 51.80, H
(OC)5W{μ-CNCH(CO2Et)}FeCp(CO)2 (4): At –78 °C a solution
containing Li[W(CNCHCO2Et)(CO)5] (0.71 mmol) (see preceding
procedure) reacted with FeCp(Cl)(CO)2 (0.15 g, 0.70 mmol), after-
wards the mixture was allowed to warm to room temperature. Removal
of the solvent left a red residue, which was extracted with ethyl ether
(3 × 20 mL). The combined orange-red ether extracts were again taken
to dryness, and the resulting material was recrystallized from CH2Cl2/
n-hexane (1:1) at –25 °C to give orange crystals of 4, m.p. 72 °C.
Yield 0.13 g (31 %). On further addition of n-hexane deep red
[FeCp(CO)2]2 separated. C17H11FeNO9W (612.98): calcd. C 33.31, H
1.81, N 2.29 %; found C 33.39, H 1.81, N 2.32 %. IR (KBr): ν = 2173
˜
m [ν(CN)]; 2075 s, 2032 s, 1989 s, 1980 s, 1920 vs. [ν(CO)]; 1713 m
3.67, N 1.07, Cl 3.27 %. IR (KBr): ν = 2175 s [ν(CN)]; 2063 s, 1988
˜
[νas(CO2)ester] cm–1. IR (CH Cl ): ν = 2165 m [ν(CN)]; 2078 s, 2042
˜
2
2
s, 1955 sh, 1932 vs. [ν(CO)]; 1733 s [νas(CO2)ester]; 1202 s, 1190 sh
s, 1990 s, 1940 vs. [ν(CO)]; 1715 m [νas(CO2)ester] cm–1. 1H NMR
(60 MHz, CDCl3): δ = 4.90 (s, Cp, 5 H), 4.24 + 4.19 (s, CH + q, CH2,
[νs(CO2)ester], 550 s [ν(cis-Pt(PPh ) ] cm–1. IR (CH Cl ): ν = 2175 s
˜
3 2
2
2
[ν(CN)]; 2065 s, 1995 sh, 1932 vs. [ν(CO)]; 1732 s [νas(CO2)ester];
1190 s [νs(CO2)ester] cm–1. 1H NMR (60 MHz, CDCl3): δ = 7.8–6.9
(m, Ph, 30 H), 4.0–3.7 (m, CNCH + CO2CH2Me, 3 H), 4.26 (q,
3
3 H), 1.32 (t, Me, JHH = 7.0 Hz, 3 H). MS (EI, 70 eV, 150 °C): m/
z = 613 (89) [M]+; 585 (2), 557 (38), 529 (18), 501 (42), 473 (100),
445 (91), 417 (94) [M – n(CO)]+ (n = 1–7); 540 (4) [M – CO2Et]+.
3
CO2CH2Me + CNCH, 3 H), 1.44 (t, CO2CH2CH3, JHH = 7.0 Hz, 3
H).
(OC)5Cr{μ-CNCH(CO2Et)}Pt(Cl)(PEt3)2 (5a):
A
solution of
Cr(CO)5CNCH2CO2Et (1.470 g, 4.80 mmol) in THF (5 mL) was
cooled to –65 °C. To this LinBu (310 mg, 4.80 mmol) (15 % solution
in n-hexane) was added dropwise. After 5 min a suspension of cis-
PtCl2(PEt3)2 (2.42 g, 4.80 mmol) in THF (20 mL) was added whilst
stirring. Stirring was continued for 4 h, during this time the mixture
was allowed to warm to room temperature. A cloudy solution had
formed, which was filtered and the solvents were evaporated to dry-
ness. Through grinding in petroleum ether (40 mL) the resulting yel-
low-brown oil could be brought to crystallize. The off-white powder
was dissolved in 25 mL of CHCl3, the solution filtered and concen-
trated to about 5 mL. Layering with petroleum ether caused large col-
orless parallelepipeds (m.p. 118 °C) to grow within 10 h. Extensive
washing of the crystals with petroleum ether or repeated recrystalliza-
tion should be avoided as this led to gradual decomposition. Yield
(OC)5Cr{μ-CNCH(CO2Me)}Pt(Cl)(PPh3)2 (7a): The complex was
prepared from Cr(CO)5CNCH2CO2Me (500 mg, 1.72 mmol) (synthe-
sized in total analogy with Cr(CO)5CNCH2CO2Et [21]), LinBu
(110 mg, 1.72 mmol), and [PtCl(PPh3)2]2(BF4)2 (1.446 g, 0.86 mmol)
as described for 6. The colorless compound [Yield 1.02 g (0.91 mmol,
53 %), m.p.: 158 °C] crystallized with one molecule of THF.
C45H34NO7ClCrP2Pt + 1THF (1117.38): calcd. C 52.67, H 3.79, N
1.25 %; found C 52.36, H 3.84, N 0.93 %. IR (KBr): ν = 2180 s
˜
[ν(CN)]; 2070 s, 1990 m, 1932 vs. [ν(CO)]; 1738 s [νas(CO2)ester]; 1205
m, 1185 sh [νs(CO2)ester] cm–1. IR (CH Cl ): ν = 2180 s [ν(CN)]; 2060
˜
2
2
s, 1990 sh, 1945 vs. [ν(CO)]; 1745 s [νas(CO2)ester]; 1190 m
1
[νs(CO2)ester] cm–1. H NMR (60 MHz, CDCl3): δ = 7.7–7.1 (m, Ph,
30 H), 3.9–3.6 (m, CNCH + CO2CH3 + C4H8O, 12 H).
3.06 g (83 %). C22H36NO7ClCrP2Pt (771.03): calcd. C 34.27, H 4.71, (OC)5W{μ-CNCH(CO2Me)}Pt(Cl)(PPh3)2 (7b): The complex was
N 1.82 %; found C 34.59, H 4.70, N 1.81 %. IR (KBr): ν = 2180 s prepared from W(CO)5CNCH2CO2Me (100 mg, 0.24 mmol) (synthe-
˜
[ν(CN)]; 2068 s, 1988 s, 1945 vs, 1908 vs. [ν(CO)]; 1729 sh, 1722 s sized in total analogy with W(CO)5CNCH2CO2Et [21]), LinBu
1344
www.zaac.wiley-vch.de
© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2010, 1339–1346

Metallo Nitrile Ylides and Metallo Nitrile Imines as Ligands [1]
(15 mg, 0.24 mmol) and [PtCl(PPh3)2]2(BF4)2 (199 mg, 0.12 mmol) vs. [ν(CO)] cm–1. 1H NMR (60 MHz, CDCl3, 40 °C): δ = 8.22 (broad
as described for 6. Yield 0.18 g (0.15 mmol, 62 %). M.p.: 176 °C. s, NH, 1 H), 7.20 (m, Ph, 30 H).
C45H34NO7ClP2PtW (1177.12): calcd. C 45.92, H 2.91, N 1.19 %;
X-ray Structure of 5b: Single crystals suitable for X-ray diffraction
studies were grown from a concentrated THF solution of 5b layered
with petroleum ether. Crystallographic data were collected with a
PHILIPS PW 1100 four circle-diffractometer at 20 °C in the ω-2θ scan
mode using Ag-Kα-radiation (λ = 0.5583 Å) and a graphite-monochro-
mator. Neither absorption nor extinction corrections were carried out.
The phase problem was solved by applying the heavy atom approach,
and the structure developed using alternative cycles of full-matrix
least-squares refinement and difference-Fourier synthesis. Though at
this stage most of the hydrogen positions could be made out, only that
of H1 (located at the asymmetric carbon atom C1) was included in the
list of atoms to be refined. All ethyl hydrogen coordinates were calcu-
lated and the C2H5 groups subsequently treated as “rigid bodies”. The
calculations were carried out using the program system SHELX-76
[55] with scattering factors for neutral atoms taken from the literature
[56]. The molecular plot was produced with the ORTEP program [57].
found C 43.90, H 3.16, N 1.19 %. IR (KBr): ν = 2180 s [ν(CN)]; 2070
˜
s, 1982 s, 1930 vs, b [ν(CO)]; 1738 s [νas(CO2)ester]; 1205 s, 1185 sh
[νs(CO2)ester] cm–1. IR (CH Cl ): ν = 2180 s [ν(CN)]; 2065 s, 1980 sh,
˜
2
2
1940 vs. [ν(CO)]; 1743 s [νas(CO2)ester]; 1190 m [νs(CO2)ester] cm–1.
[(PPh3)2(Cl)Pt{μ-CNCH(CO2Me)}Pt(Cl)(PPh3)2]BF4
(8):
[Pt(Cl)(CNCH2CO2Et)(PPh3)2]BF4 (250 mg, 0.26 mmol), KOtBu
(30 mg, 0.26 mmol), and [(Ph3P)2Pt(μ-Cl)2Pt(PPh3)2](BF4)2 (219 mg,
0.13 mmol) were suspended in dichloromethane (40 mL) and stirred
for 2 h at room temperature. The solvent was removed and the color-
less powdery residue was stirred in ethyl ether (60 mL) for 12 h. The
product was collected on a frit, dried at 40 °C in high vacuum and
recrystallized from CH2Cl2/ether to give 0.31 (0.18 mmol, 69 %) of
colorless
rod-shaped
crystals
[m.p.:
294 °C
(dec.)].
C77H66NO2BCl2F4P4Pt2 (1709.18): calcd. C 54.11, H 3.89, N 0.82 %;
found C 54.14, H 4.31, N 0.82 %. IR (KBr): ν = 2230 m [ν(CN)]; 1720
˜
m, b [νas(CO2)ester]; 1195 s [νs(CO2)ester]; 1060 vs, b [ν(BF4)] cm–1. IR
C22H36ClNO7P2PtW (902.9), monoclinic, P21/c (Nr. 14),
a =
(CH Cl ): ν = 2225 s [ν(CN)]; 1720 s, 1710 m [ν (CO2)ester]; 1202 m
˜
2
2
as
[νs(CO2)ester]; 1055 vs. [ν(BF4)] cm–1.
14.077(4), b = 9.353(3), c = 24.127(6) Å, β = 97.75(2)°, V =
3147.6 Å3, Z = 4, ρobsd. = 1.89(2), ρcalcd. = 1.905 Mg·m–3, temperature =
293 K, 2θ range for data collection = 3.0–22.0°, reflections collected =
8523, independent reflections = 4273, Rint = 0.0324 %, observed re-
flections = 2953 [I ≥ 2σ (I)], parameters (refined) = 292, F(000) =
1720, R = 5.97 %.
(OC)5Cr{μ3-CNCPh}[Pt(Cl)(PPh3)2]2
(9):
Cr(CO)5CNCH2Ph
(309 mg, 1.0 mmol) and [(Ph3P)2Pt(μ-Cl)2Pt(PPh3)2](BF4)2 (1.684 g,
1.0 mmol) were dissolved in THF (20 mL). To this sodium hydride
(24 mg, 1.0 mmol) (from a 50 % suspension in paraffin) was added
at –78 °C and the mixture was allowed to warm to –40 °C during 2 h.
A solution of n-butyllithium (64 mg, 1.0 mmol) in THF (10 mL) was
added dropwise at first resulting in an intensive orange coloring, which
turned to bright green after a while. Warming up to room temperature
led to a red solution, which was filtered through cellulose (0.5 × 5 cm-
column), concentrated to about 1/5 of the original volume and layered
with a small amount of petroleum ether. On standing at 6 °C for a
couple of hours a microcrystalline powder separated. Repeated recrys-
tallization from THF/petroleum ether resulted in diamond-shaped col-
orless single crystals. Yield 0.20 g (0.11 mmol, 11 %). M.p.: 286 °C
(dec.). C85H65NO5Cl2CrP4Pt2 (1817.46): calcd. C 56.17, H 3.60, N
Crystallographic data for the structure have been deposited with the
Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge
CB21EZ. Copies of the data can be obtained on quoting the depository
numbers CCDC-757433 (5b). (www.ccdc.cam.ac.uk/data_request/cif;
Fax: +44-1223-336-033; E-Mail: deposit@ccdc.cam.ac.uk).
Acknowledgement
Financial support for this work by the Fonds der Chemischen Indus-
trie, the Deutsche Forschungsgemeinschaft, the BMBW (Graduierten-
kolleg “Synthesis and Structure of Low Molecular Compounds”) and
the BAYER AG is gratefully acknowledged.
0.77 %; found C 56.33, H 3.81, N 0.69 %. IR (KBr): ν = 2160 s
˜
[ν(CN)]; 2055 s, 1990 m, 1950 sh, 1927 vs, b [ν(CO)] cm–1. IR
(CH Cl ): ν = 2160 s [ν(CN)]; 2055 s, 1985 sh, 1940 vs. [ν(CO)] cm–1.
˜
2
2
(OC)5Cr{μ-CNN(H)}FeCp(CO)2
(10):
(a)
Preparation
of
References
NEt3H[Cr{CNNH}(CO)5]: A solution of Cr(CO)5CNNH2 (0.24 g,
1.0 mmol) in THF (40 mL) was cooled in an ice bath. To it a fourfold [1] Metal Complexes of Functional Isocyanides, Part 32. Part 31: F.
Schoder, U. Plaia, R. Metzner, W. Sperber, W. Beck, W. P. Fehl-
hammer, Z. Anorg. Allg. Chem. 2010, DOI: 10.1002/
zaac.200900456.
molar amount of NEt3 was added, and the mixture war stirred for
15 min after which it could be employed in further reactions. (b) Reac-
tion with FeCl(Cp)(CO)2: The nitrile imine solution (see above) was
cooled to –78 °C. FeCl(Cp)(CO)2 (0.21 g, 1.0 mmol) was added, and
the mixture was allowed to warm to room temperature overnight. The
red to orange solution was taken to dryness, and the residue was ex-
tracted with three 20 mL portions of ethyl ether. Removal of the sol-
vent from the combined extracts followed by recrystallization of the
crude product gave 0.13 g (32 %) of 10 as an ochre powder. IR (KBr):
[2] N. H. Toubro, A. Holm, J. Am. Chem. Soc. 1980, 102, 2093; H.-
J. Hansen, H. Heimgartner, Nitrile Ylides, p. 177, P. Caramella,
P. Grünanger, Nitrile Oxides and Imines, p. 291, in 1,3-Dipolar
Cycloaddition Chemistry (Ed.: A. Padwa) vol. 1, Wiley, New
York, 1984; J. T. Sharp, Nitrile Ylides and Nitrile Imines in The
Chemistry of Heterocyclic Compounds, Vol. 59: Synthetic Appli-
cations of 1,3-Dipolar Cycloaddition Chemistry Toward Hetero-
cycles and Natural Products (Eds.: A. Padwa, W. H. Pearson)
Wiley, New York, 2002.
ν = 3380 vw [ν(NH)]; 2212 m [ν(CN)]; 2125 m, 2060 s, 1985 sh, 1918
˜
vs. [ν(CO)] cm–1.
[3] a) R. Huisgen, Angew. Chem. 1963, 75, 604; Angew. Chem. Int.
Ed. Engl. 1963, 2, 565; b) R. Huisgen, Angew. Chem. 1963, 75,
742; Angew. Chem. Int. Ed. Engl. 1963, 2, 633; c) R. Huisgen, J.
Org. Chem. 1976, 41, 403; d) R. Huisgen, 1,3-Dipolar Cycloaddi-
tions – Introduction, Survey, Mechanism, p. 1 in 1,3-Dipolar Cy-
cloaddition Chemistry (Ed.: A. Padwa) vol. 1, Wiley, New York,
1984; e) R. Huisgen, The Adventure Playground of Mechanisms
and Novel Reactions, ACS, Washington DC, 1994.
(OC)5Cr{μ-CNN(H)}Pt(Cl)(PPh3)2 (11): NEt3H[Cr{CNNH}(CO)5]
(0.5 mmol) reacted with [PtCl(PPh3)2]2(BF4)2 (0.42 g, 0.25 mmol) as
described for 10. An analogous work-up procedure gave 0.3 g (61 %)
of 11 as a pale yellow powder. C42H31ClCrN2O5P2Pt (988.34): calcd.
C 51.05, H 3.16, N 2.83 %; found C 51.57, H 3.75, N 3.06 %. IR
(KBr): ν = 3420 w [ν(NH)]; 2235 w [ν(CN)]; 2060 m, 1980 m, 1926
˜
Z. Anorg. Allg. Chem. 2010, 1339–1346
© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.zaac.wiley-vch.de
1345

W. P. Fehlhammer et al.
ARTICLE
[4] a) E. P. Janulis Jr, S. R. Wilson, A. J. Arduengo III, Tetrahedron [30] K. Suzuki, H. Yamamoto, S. Kanie, J. Organomet. Chem. 1974,
Lett. 1984, 25, 405; b) C. Wentrup, S. Fischer, H. M. Bestermann,
M. Kuzaj, H. Lüerssen, K. Burger, Angew. Chem. 1986, 98, 99;
Angew. Chem. Int. Ed. Engl. 1986, 25, 85.
73, 131.
[31] H. C. Clark, L. E. Manzer, Inorg. Chem. 1972, 11, 2749.
[32] S. H. Mastin, Inorg. Chem. 1974, 13, 1003.
[33] A. M. van Leusen, personal communication.
[34] W. P. Fehlhammer, F. Degel, H. Stolzenberg, Angew. Chem. 1981,
93, 184; Angew. Chem. Int. Ed. Engl. 1981, 20, 214.
[35] T. Saegusa, Y. Ito, H. Kinoshiba, S. Tomita, J. Org. Chem. 1971,
36, 3316.
[5] a) G. Sicard, A. Baceiredo, G. Bertrand, J. Am. Chem. Soc. 1988,
110, 2663; b) G. Bertrand, C. Wentrup, Angew. Chem. 1994, 106,
549; Angew. Chem. Int. Ed. Engl. 1994, 33, 527.
[6] a) N. Goldberg, M. Iraqi, H. Schwarz, Chem. Ber. 1993, 126,
2353; b) G. Maier, C. Schmid, H. P. Reisenauer, E. Endlein, D.
Becker, J. Eckwert, B. A. Hess Jr, L. J. Schaad, Chem. Ber. 1993,
126, 2337.
[7] N. Goldberg, A. Fiedler, H. Schwarz, Helv. Chim. Acta 1994, 77,
2354.
[8] W. P. Fehlhammer, F. Schoder, B. Weinberger, H. Stolzenberg, W.
Beck, Z. Anorg. Allg. Chem. 2009, 635, , ,1367.
[36] a) E. B. Dreyer, C. T. Lam, S. J. Lippard, Inorg. Chem. 1979, 18,
1904; b) M. P. Guy, J. T. Guy Jr, D. W. Bennett, Organometallics
1986, 5, 1696; c) F. E. Hahn, M. Tamm, J. Organomet. Chem.
1994, 467, 103.
[37] J. Howard, P. Woodward, J. Chem. Soc., Dalton Trans. 1973,
1840.
[9] a) W. P. Fehlhammer, K. Bartel, W. Petri, J. Organomet. Chem.
1975, 87, C34; b) W. P. Fehlhammer, K. Bartel, A. Völkl, D.
Achatz, Z. Naturforsch. 1982, 37b, 1044; c) G. Zinner, W. P.
Fehlhammer, Angew. Chem. 1985, 97, 990; Angew. Chem. Int. Ed.
Engl. 1985, 24, 979; d) W. P. Fehlhammer, G. Zinner, M. Bakola-
Christianopoulou, J. Organomet. Chem. 1987, 331, 193; e) U.
Eckert, C. Robl, W. P. Fehlhammer, Organometallics 1993, 12,
3241.
[38] a) R. Ugo, F. Conti, S. Cenini, R. Mason, G. B. Robertson, J.
Chem. Soc., Chem. Commun. 1968, 1498; b) F. Cariati, R. Mason,
G. B. Robertson, R. Ugo, J. Chem. Soc., Chem. Commun. 1967,
408.
[39] R. Mason, C. W. Meek, Angew. Chem. Int. Ed. Engl. 1978, 17,
183.
[40] A. Del Pra, G. Zanotti, A. Piazzesi, U. Belluco, R. Ros, Transi-
tion. Met. Chem. 1979, 4, 381.
[10] W. P. Fehlhammer, H. Hoffmeister, U. Eckert, Z. Naturforsch.
1993, 48b, 1448.
[41] D. R. Russell, P. A. Tucker, J. Chem. Soc., Dalton Trans. 1975,
2222.
[11] K. Bartel, PhD-Thesis, University of Munich, 1976.
[12] G. Zinner, M. Bakola-Christianopoulou, W. P. Fehlhammer in Or-
ganometallic Syntheses, (Eds.: R. B. King, J. J. Eisch) vol. 4,
Elsevier, Amsterdam, 1988, pp. 82.
[42] J. A. Kaduk, J. A. Ibers, J. Organomet. Chem. 1977, 139, 199.
[43] A. Del Pra, G. Zanotti, G. Bombieri, R. Ros, Inorg. Chim. Acta
1979, 36, 121.
[13] a) B. Weinberger, W. P. Fehlhammer, Angew. Chem. 1980, 92,
478; Angew. Chem. Int. Ed. Engl. 1980, 19, 480; b) B. Weinber-
ger, W. P. Fehlhammer, Chem. Ber. 1985, 118, 42.
[44] M. A. Bennett, H.-K. Chee, G. B. Robertson, Inorg. Chem. 1979,
18, 1061.
[45] A. Del Pra, E. Forsellini, G. Bombieri, R. A. Michelin, R. Ros,
J. Chem. Soc., Dalton Trans. 1979, 1862.
[14] W. Hieber, E. Winter, E. Schubert, Chem. Ber. 1962, 95, 3070.
[15] H. Bock, H. tom Dieck, Z. Naturforsch. 1966, 21b, 739.
[16] K. A. O. Starzewski, H. tom Dieck, K. D. Franz, F. Hohman, J.
Organomet. Chem. 1972, 42, C35.
[46] a) M. J. S. Dewar, I. J. Turchi, J. Chem. Soc. Perkin Trans. 2,
1977, 724; b) E. C. Taylor, I. J. Turchi, Chem. Rev. 1979, 79, 181.
[47] Organic nitrile imines were first prepared by Huisgen and co-
workers: R. Huisgen, M. Seidel, J. Sauer, J. W. McFarland, G.
Wallbillich, J. Org. Chem. 1959, 24, 892; R. Huisgen, M. Seidel,
G. Wallbillich, H. Knupfer, Tetrahedron 1962, 18, 3; High-level
ab initio MO calculations predict that the parent nitrile imine pre-
fers a non planar, allenic structure: M. W. Wong, C. Wentrup, J.
Am. Chem. Soc. 1993, 115, 7743.
[17] F. Heydenreich, A. Mollbach, G. Wilke, H. Dreeskamp, E. G.
Hoffmann, G. Schroth, K. Seevogel, W. Stempfle, Isr. J. Chem.
1972, 12, 293.
[18] F. R. Kreißl, C. G. Kreiter, E. O. Fischer, Angew. Chem. 1972,
84, 679; Angew. Chem. Int. Ed. Engl. 1972, 11, 643.
[19] L. Knoll, J. Organomet. Chem. 1978, 148, C25.
[20] E. Lindner, H. Berke, Chem. Ber. 1974, 107, 1360.
[21] W. C. Kaska, D. K. Mitchell, R. F. Reichelderfer, J. Organomet.
Chem. 1973, 47, 391.
[48] B. Weinberger, G. Zinner, W. P. Fehlhammer, in Organometallic
Syntheses (Eds.: R. B. King, J. J. Eisch), Vol. 4, Elsevier, Amster-
dam, 1988, pp. 87.
[22] a) W. P. Fehlhammer, R. Metzner, R. Kunz, Chem. Ber. 1994,
127, 321; b) W. P. Fehlhammer, R. Metzner, W. Sperber, Chem. [49] [Re(CO)6]PF6 was prepared analogous to [Re(CO)6]BF4: D. J.
Ber. 1994, 127, 631.
Darensbourg, J. A. Froehlich, J. Am. Chem. Soc. 1977, 99, 4716.
[50] a) L. Busetto, U. Belluco, R. J. Angelici, J. Organomet. Chem.
1969, 18, 213; b) B. D. Dombek, R. J. Angelici, Inorg. Synth.
1977, 17, 100.
[51] W. P. Fehlhammer, W. A. Herrmann, K. Öfele, in Handbuch der
Präparativen Anorganischen Chemie (Ed.: G. Brauer), Vol. III,
Ferdinand Enke, Stuttgart, 3rd edn., 1981.
[52] a) B. F. Hallam, P. L. Pauson, J. Chem. Soc. 1956, 3030; b) K. K.
Joshi, P. L. Pauson, W. H. Stubbs, J. Organomet. Chem. 1963, 1,
51.
[53] W. Strohmeier, Angew. Chem. 1964, 76, 873.
[54] J. C. Hileman, D. K. Huggins, H. D. Kaesz, Inorg. Chem. 1962,
1, 933.
[55] G. Sheldrick, SHELX-76, University of Cambridge, UK, 1976.
[56] D. T. Cromer, J. T. Waber, International Tables for X-ray Crystal-
lography, Kynoch Press, Birmingham, UK, 1974, vol. 4.
[57] C. K. Johnson, ORTEP, Rep. ORNL-5138, Oak Ridge National
Laboratory, Oak Ridge, TN, USA, 1976.
[23] Due to partial hydrolysis of W(CO)5CNCHPPh3 the 1H NMR res-
onance of the methin proton could not be assigned with certainty.
The
values
for
the
coordination
compound
2
([W(CO)5CNCH2PPh3]PF6: δ = 5.58, JPH = 8 Hz) compare well
with those of the free isocyanide.
[24] a) D. Achatz, PhD-Thesis, University of Erlangen-Nürnberg,
1982; b) Deprotonation by Na[N(SiMe325783Z. Naturforsch. 1976,
31b, 1019; c) H. Behrens, M. Moll, Z. Anorg. Allg. Chem. 1975,
416, 193.
[25] W. P. Fehlhammer, A. Völkl, U. Plaia, G. Beck, Chem. Ber. 1987,
120, 2031.
[26] G. Bittner, H. Witte, G. Hesse, Justus Liebigs Ann. Chem. 1968,
713, 1.
[27] D. Achatz, M. A. Lang, A. Völkl, W. P. Fehlhammer, W. Beck,
Z. Anorg. Allg. Chem. 2005, 631, 2339.
[28] These data compare well with those of cis-[Pt(Cl)(Me)(PEt3)2]
[δ(P1) –14.6, 1J(Pt,P)
= 1719 Hz (trans-Me); δ(P2) –8.7,
1J(Pt,P) = 4179 Hz (trans-Cl)]: F. H. Allen, A. Pidcock, J. Chem.
Soc. A 1968, 2700.
Received: November 24, 2009
Published Online: March 8, 2010
[29] M. A. Bennett, R. Bramley, J. B. Tomkins, J. Chem. Soc., Dalton
Trans. 1973, 166.
1346
www.zaac.wiley-vch.de
© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2010, 1339–1346