Palladium chemistry with stanna-closo-dodecaborate and isocyanides

Article abstract of DOI:10.1002/ejic.201000292

The substitution equilibrium between isocyanides and stanna-closo- dodecaborate with palladium(II) was investigated. The mixed substituted products of type [(RNC)₂Pd(SnB₁₁H₁₁)₂] ^2- and [(RNC)Pd(SnB

Full text of DOI:10.1002/ejic.201000292

FULL PAPER
DOI: 10.1002/ejic.201000292
Palladium Chemistry with Stanna-closo-dodecaborate and Isocyanides
Martin Hornung[a] and Lars Wesemann*[a]
Keywords: Palladium / Tin / Boron / Cluster compounds / Insertion / Isocyanide
The substitution equilibrium between isocyanides and
stanna-closo-dodecaborate with palladium(II) was investi-
gated. The mixed substituted products of type [(RNC)2Pd-
(SnB11H11)2]2– and [(RNC)Pd(SnB11H11)3]4– were charac-
terized by X-ray crystal structure analysis, elemental analysis
and NMR spectroscopy. Isocyanide insertion into palladium–
carbon bonds was also found. The zwitterionic complexes
isolated from the reaction of [(PЈ2)Pd(Me)(SnB11H11)]– (PЈ2
=
dppe, dppp, dppf) with isocyanides were characterized.
Introduction
Results and Discussion
We have shown in recent publications that the dianionic
tin ligands [EB11H11]2– (E = Ge, Sn) substitute halides in
various transition metal complexes and furthermore are
able to replace chelating diolefin ligands like 1,5-cyclo-
octadiene in [(COD)PtCl2] and [(COD)PdCl2] to give the
tetrasubstituted hexaanionic complexes [M(EB11H11)4]6–
(M = Pd, Pt; E = Ge, Sn).[21,25] Thus it is not surprising,
that a mixture of isocyanide palladium complex [(RNC)2-
PdCl2] (RNC = benzyl, tert-butyl, cyclohexyl, 2,6-di-
methylphenyl) with four equivalents of tin nucleophile re-
acts to give the known square-planar complex
[Pd(SnB11H11)4]6–.[22–30] In the case of the salt [Et3MeN]6-
[Pd(SnB11H11)4] (1) we were able to solve the disorder prob-
lem of the cation in the crystal structure solution.[25] In Fig-
ure 1 the square-planar-coordinated palladium complex is
shown. Details of the crystal structure analysis are listed in
Table 1.
Palladium isocyanide chemistry is of interest in catalysis
with respect to a variety of bond formation reactions.[1–8]
For example palladium isocyanide complexes can act as ef-
ficient catalysts in the Suzuki–Miyaura reaction.[8] Further-
more, element–carbon bonds like Sn–C are formed with iso-
cyanide palladium complexes [(tBuNC)2PdCl2] as catalysts.
In these cases bistannylation of alkynes or arynes was car-
ried out under palladium catalysis. In the course of these
reactions the formation of the intermediate [(RNC)2Pd-
(SnRЈ3)2] was proposed. Oxidative addition of hexaalkyl-
ditin [RЈ3Sn–SnRЈ3] at palladium complexes in formal oxi-
dation state zero Pd0 or substitution at the dichloride
[(RNC)2PdCl2] are the discussed reaction pathways for the
formation of the possible intermediate.[5–7] So far complexes
of the discussed intermediate type have not been charac-
terized by single-crystal structure solution. However com-
plexes with the trichlorostannate ligand [SnCl3]– like
[(CNR)2Pd(SnCl3)2] (R = Ph, Cy) were characterized by el-
emental analysis and IR spectroscopy.[9,10] Besides coordi-
nating at palladium atoms isocyanides can also insert into
palladium–carbon bonds, palladium–platinum bonds or re-
act catalytically with palladium complexes to insert into sili-
con–silicon or silicon–tin bonds.[11–20]
As part of our coordination chemistry project we
are studying the ligand abilities of the germylene and
stannylene type ligands [GeB11H11]2–, [SnB11H11]2–,
[SnCHB10H10]–, [Ge2B10H10]2– and [Sn2B10H10]2–.[21–33] In
this publication we are presenting the results of our studies
of the palladium coordination chemistry with stanna-closo-
dodecaborate and isocyanide ligands. Substitution reactions
and insertion reactions are discussed.
Figure 1. Molecular structure of the anion of [Et3MeN]6[Pd-
(SnB11H11)4] (1), hydrogen atoms and cations have been omitted for
clarity, ellipsoids with 50%. Interatomic distances [Å] and angles [°]
Pd1–Sn1 2.5625(6), Pd1–Sn2 2.5629(6), Sn1–Pd1–Sn2 89.90(2).
From the reaction mixtures of four isocyanide palladium
dichloride complexes [(RNC)2PdCl2] (RNC = benzyl, tert-
butyl, cyclohexyl, 2,6-dimethylphenyl) with two equivalents
of the tin nucleophile [SnB11H11]2– (Scheme 1) we were able
[a] Institut für Anorganische Chemie, Universität Tübingen,
Auf der Morgenstelle 18, 72076 Tübingen, Germany
Fax: +49-7071-292436
E-mail: lars.wesemann@uni-tuebingen.de
Eur. J. Inorg. Chem. 2010, 2949–2955
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
2949

M. Hornung, L. Wesemann
FULL PAPER
Table 1. Crystal and structure refinement parameters of 1, 2, 3 and 4.
1
2
3
4
Empirical formula
Mr [gmol–1]
Wavelength [Å]
Temperature [K]
Crystal system
Space group
Z
a [Å]
b [Å]
c [Å]
α [°]
C42H152B44N6PdSn4
1798.65
0.71073
173
monoclinic
P21/c
C28H68B22N4PdSn2 C36H100B22Cl4N4PdSn2 C45H133B33N8Pd1Sn3
1042.46
0.71073
173
1312.71
0.71073
173
monoclinic
P21/n
1605.92
0.71073
173
monoclinic
P21/n
triclinic
¯
P1
2
1
2
4
10.7581(8)
16.9313(10)
25.3051(14)
90
99.430(5)
90
4547.0(5)
1.314
1.310
8.2055(11)
9.9410(12)
14.6716(18)
89.822(10)
81.242(10)
85.592(10)
1179.3(3)
1.468
16.1951(12)
10.7196(5)
20.1237(15)
90
110.959(6)
90
33.953(2)
12.6386(7)
19.5441(12)
90
104.813(5)
90
β [°]
γ [°]
Volume [Å3]
Density ρcalcd. [g/cm3]
Absorption coefficient µ [mm–1]
F(000)
3262.4(4)
1.336
8108.0(8)
1.315
1.456
520
1.226
1336
1.168
3280
1824
Crystal size [mm3]
Theta range [°]
Index range
0.2ϫ0.2ϫ0.1
5.67 to 25.35
–12 Յ h Յ 12
–20 Յ k Յ 20
–29 Յ l Յ 30
50472
0.2ϫ0.2ϫ0.1
5.67 to 25.35
–9 Յ h Յ 9
–11 Յ k Յ 11
–17 Յ l Յ 17
14368
0.2ϫ0.2ϫ0.2
5.68 to 25.35
–19 Յ h Յ 19
–12 Յ k Յ 11
–22 Յ l Յ 24
25093
0.2ϫ0.2ϫ0.2
5.67 to 25.35
–40 Յ h Յ 40
–14 Յ k Յ 15
–23 Յ l Յ 23
96549
Reflections collected
Independent reflections/Rint
Completeness
Absorption correction
Max./min. transmission
Parameters/restraints
8219/0.0926
98.8%
numerical
0.8796/0.6934
381/151
4252/0.0915
98.7%
numerical
0.8808/0.7337
259/0
5666/0.0673
94.8%
numerical
0.8713/0.7686
327/106
14674/0.0934
98.8%
numerical
0.4159/0.3287
952/445
R1/wR2 indices [IϾ2σ(I)]
R1/wR2 for all reflections
Goodness-of-fit on F2
Largest diff. peak/hole [eA–3]
0.0837/0.1977
0.1054/0.2115
1.128
0.0394/0.0783
0.0548/0.0827
1.051
0.0671/0.1592
0.0890/0.1745
1.102
0.0685/0.1427
0.0890/0.1529
1.052
1.769/–1.661
0.823/–1.158
1.542/–0.710
1.992/–1.692
to isolate mixed substitution products (see Figures 2, 3, 4, crystallization purposes. In Figures 2–5 the anionic iso-
and 5). Although after two days of reaction time the known cyanide palladium complexes are shown. Details of the
tetrasubstituted complex 1 is the only reaction product with crystal structure analysis are listed in Tables 1 and 2.
a tin ligand. Obviously the adjustment of the substitution
In isocyanide coordination chemistry the value of the
equilibrium is slow enough to prepare mixed-substitution stretching frequency ν(CϵN) together with the angle at ni-
products only, and the homoleptically tetrasubstituted com- trogen in CϵN–C–RЈ are diagnostic tools for the interpret-
plexes have the highest stability in this mixture. The mixed ation of the bonding situation of the ligands and the metal
isocyanide complexes [Et3NH]2[trans-(C6H5CH2–NϵC)2- centre. In complexes 2–5 the respective IR frequencies
Pd(SnB11H11)2] (2), [Bu3NH]2[trans-(Me3C–NϵC)2Pd- ν(CϵN) exhibit higher values (58–73 cm–1) than the respec-
(SnB11H11)2] (3), [Et4N]4[(C6H11–NϵC)Pd(SnB11H11)3] (4) tive uncoordinated molecules.[34] Furthermore, in the solid
and, [Et4N]4[(2,6-Me2C6H3–NϵC)Pd(SnB11H11)3] (5) were state the isocyanides show nearly linear coordination
isolated after crystallization and characterized by NMR (angles at N M–C1–N–C2: 176.0–178.9°). Both features are
spectroscopy, single crystal structure analysis and elemental significant for low π-back bonding in the isocyanide bond
analysis (Scheme 1). The countercation was varied due to and indicate low electron density at the palladium atom.
Scheme 1. Possible substitution equilibrium showing the formation of the (with respect to the tin ligand) mono-, di-, tri- and tetrasubsti-
tuted palladium complexes (L = isocyanide).
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© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2010, 2949–2955

Pd Chemistry with Sn/B Clusters and Isocyanides
Figure 2. Molecular structure of the anion of [Et3NH]2[trans-
(C6H5CH2–NϵC)2Pd(SnB11H11)2] (2), hydrogen atoms and cations
have been omitted for clarity, ellipsoids with 50%. Interatomic dis-
tances [Å] and angles [°]: Pd1–Sn1 2.5640(4); Pd1–C1 1.970(5); C1–
N1 1.143(6); C1–Pd1–Sn1 90.1(1), C1–N1–C2 178.8(5).
Figure 5. Molecular structure of the anion of [Et4N]4[(2,6-
Me2C6H3–NϵC)Pd(SnB11H11)3] (5), hydrogen atoms and cations
have been omitted for clarity, ellipsoids with 50%. Interatomic dis-
tances [Å] and angles [°]: Pd1–Sn1 2.5611(4), Pd1–Sn2 2.5351(4),
Pd1–Sn3 2.5515(4), Pd1–C1 1.978(4), C1–N1 1.148(5), Sn2–Pd1–
Sn1 86.82(1), C1–Pd1–Sn1 92.7(1), Sn2–Pd1–Sn3 89.77(1), C1–
Pd1–Sn3 91.0(1), C1–Pd1–Sn2 176.5(1), Sn3–Pd1–Sn1 174.39(1),
C1–N1–C2 178.9(4).
trend: trans-oriented tin ligands exhibit Pd–Sn bond lengths
of 2.56 Å, whereas the tin ligands in 4 and 5 trans to the
isocyanide show slightly shorter distances of 2.53 Å to pal-
ladium. This might be an indication of the slightly weaker
trans influence of the isocyanide ligand.
Figure 3. Molecular structure of the anion of [Bu3NH]2[trans-
(Me3C–NϵC)2Pd(SnB11H11)2] (3), hydrogen atoms and cations
have been omitted for clarity, ellipsoids with 50%. Interatomic dis-
tances [Å] and angles [°]: Pd1–Sn1 2.5589(5), Pd1–C1 1.96(1), C1–
N1 1.13(1), C1–Pd1–Sn1 89.0(2), C1–N1–C2 176.0(9).
NMR Spectroscopy in Solution
The reactions were monitored by 119Sn{1H} NMR spec-
troscopy in solution. The uncoordinated heteroborate
shows a resonance at δ = –540 ppm, whereas the tin for
coordinated stanna-closo-dodecaborate shows a signal at
chemical shifts in an area from –300 to –350 ppm. The reac-
tion mixture of [cis-(isocyanide)2PdCl2] with two equiva-
lents of ligand [SnB11H11]2– displays in the 119Sn NMR
spectrum three broad signals in the range of δ = –305 ppm
–330 ppm at the beginning of the reaction, which probably
indicatestheformationofthreeproducts[trans-(isocyanide)2-
Pd(SnB11H11)2]2–,
[(isocyanide)Pd(SnB11H11)3]4–
and
[Pd(SnB11H11)4]6–. After 48 h the signal of [trans-(isocy-
anide)2Pd(SnB11H11)2]2– almost disappeared and the signal
of [Pd(SnB11H11)4]6– has increased. In the 11B NMR spec-
trum the uncoordinated heteroborate shows resonances at
δ = –6, –11 and –13 ppm with an intensity ratio of 1:5:5,
whereas for the coordination of the stanna-closo-dodecabo-
rate to a transition metal shows only one peak at δ ≈
–15 ppm for ten boron atoms. Compounds 1 und 2 exhibit
two signals in the 11B{1H} NMR spectrum at –9.3 (B12),
–14.8 (B2–B11) ppm and –9.4 (B12), –15.0 (B2–B11) ppm,
Figure 4. Molecular structure of the anion of [Et4N]4[(C6H11–
NϵC)Pd(SnB11H11)3] (4), hydrogen atoms and cations have been
omitted for clarity, ellipsoids with 30%. Interatomic distances [Å]
and angles [°]: Pd1–Sn1 2.5682(7), Pd1–Sn2 2.5290(7), Pd1–Sn3
2.5622(7), Pd1–C1 1.951(11), N1–C1 1.23(2), C1–Pd1–Sn2
177.5(4), C1–Pd1–Sn3 91.4(3), Sn2–Pd1–Sn3 90.54(2), C1–Pd1–
Sn1 90.2(3), Sn2–Pd1–Sn1 87.78(2), Sn3–Pd1–Sn1 173.78(4), C1–
N1–C2 164 (disorder).
The electronic situation in the stannaborate isocyanide indicating coordination of the stanna-closo-dodecaborate li-
complexes can be compared with isocyanide trichlorostann- gand.
ate compounds of palladium.[9,10] The Pd–C bond lengths
In order to prove whether the isocyanide tin complexes
in complexes 2–5 are in the close range of 1.95–1.98 Å and react under transfer of the tin ligand on an unsaturated
lie in the area of known isocyanide palladium complexes.[35] substrate we studied the chemical behaviour of the complex
The Pd–Sn distances in compound 2–5 show an interesting [Bu3NH]2[trans-(Me3C–NϵC)2Pd(SnB11H11)2] (3) towards
Eur. J. Inorg. Chem. 2010, 2949–2955
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
2951

M. Hornung, L. Wesemann
FULL PAPER
Table 2. Crystal and structure refinement parameters of 5, 6, 7, 8 and 9.
5
6
7
8
9
Empirical formula
Mr/gmol–1
Wavelength [Å]
Temperature [K]
Crystal system
Space group
Z
C31H99B33N8PdSn3
1403.38
0.71073
173
monoclinic
P21/c
C46H70B11ClN4P2PdSn
C39H59B11N4P2PdSn C41H54B11Cl2FeNP2PdSn C42H52B11Cl2FeNP2PdSn
1120.45
0.71073
173
989.84
0.71073
173
1093.54
0.71073
173
1103.54
0.71073
173
triclinic
triclinic
P1
triclinic
P1
monoclinic
P21/c
¯
¯
¯
P1
4
2
2
2
4
a [Å]
b [Å]
c [Å]
α [°]
β [°]
γ [°]
16.4056(6)
16.2748(7)
25.5053(10)
90
93.013(3)
90
6800.4(5)
1.371
1.381
12.0401(9)
13.8578(13)
17.2027(16)
100.667(7)
104.834(7)
93.599(7)
2708.3(4)
1.374
10.6699(12)
14.2068(16)
16.8443(17)
73.907(8)
80.096(9)
87.601(9)
2416.7(5)
1.360
10.6095(12)
14.1845(16)
17.7287(19)
103.898(9)
96.639(9)
93.210(9)
2562.8(5)
1.417
13.9436(8)
18.5741(8)
18.5784(13)
90
100.319(5)
90
4733.8(5)
1.548
1.415
Volume [Å3]
Density ρcalcd. [g/cm3]
Absorption coefficient µ
[mm–1]
0.937
0.987
1.306
F(000)
2808
0.2ϫ0.2 ϫ0.2
5.67–25.35
1144
1004
1096
2208
Crystal size [mm3]
Theta range [°]
0.3ϫ0.2ϫ0.1
5.67–25.35
14, 16, 20
31028
9654/0.0655
97.2%
0.3ϫ0.2ϫ0.2
5.67–25.35
12, 17, 20
23401
8529/0.1282
96.4%
0.2ϫ0.2ϫ0.2
5.67–25.35
12, 17, 21
29399
9255/0.1148
98.6%
0.2ϫ0.2ϫ0.1
5.67–25.35
16, 22, 22
51229
8562/0.0808
98.7%
Limiting indices Ϯh, Ϯk, Ϯl 19, 19, 30
Reflections collected 80448
Independent reflections/Rint 12309/0.0693
Completeness
98.8%
Absorption correction
Max./min. transmission
Parameters/restraints
R1/wR2 indices [IϾ2σ(I)]
R1/wR2 for all reflections
Goodness-of-fit on F2
numerical
0.8675/0.7781
695/6
numerical
0.9291/0.8009
581/355
0.0443/0.0931
0.0581/0.1009
1.029
numerical
0.8862/0.7227
526/69
0.0923/0.1753
0.1358/0.1927
1.170
numerical
0.8777/0.7542
526/3
0.0776/0.1561
0.1209/0.1737
1.107
numerical
0.9999/0.4899
520/0
0.0539/0.1008
0.0683/0.1056
1.178
0.0385/0.0770
0.0497/0.0806
1.104
Largest diff. peak/hole [eA–3] 0.911/–0.768
1.158/–1.204
2.804/–1.584
1.638/–1.019
1.690/–1.502
(trimethylsilyl)acetylene at room temperature. However, tonated nitrogen atom the positive charge. In one case we
from this mixture we could not detect any reaction prod- isolated a substitution and not the insertion product: in-
ucts.
stead of the methyl substituent a cyclohexyl isocyanide is
coordinated to palladium in complex 9. This compound is
also a zwitterionic complex consisting of the dicationic
[(dppf)Pd(CϵN–C6H11)] moiety and the dianionic hetero-
borate ligand.
Insertion Reactions
In platinum stanna-closo-dodecaborate chemistry we
found activation of a Pt–C bond towards an isocyanide in-
sertion.[23] Tin ligands like SnCl3 for example are known
for activation of metal organic complexes in catalysis.[36] We
are interested in the behaviour of our coordinated tin ligand
in palladium chemistry. Here we present isocyanide inser-
tion, which was carried out starting with the palladium
methyl complex [(PЈ2)Pd(CH3)Cl] carrying three different
chelating phosphanes like PЈ2: dppe, dppp and dppf. In a
simple one pot procedure we reacted the chloride complexes
of type [(PЈ2)Pd(CH3)Cl] with the tin nucleophile
[SnB11H11]2–. (These reaction products were also isolated
and characterized for the ligands dppp and dppf.) After a
period of stirring for 1 h for in acetonitrile the respective
Scheme 2. Formation of the zwitterionic complexes 6–8. a: reaction
with one equivalent of [R3NH]2[SnB11H11] in acetonitrile; b: reac-
tion of the mixture with one equivalent of the respected isocyanide.
6: dppe, 2,6-dimethylphenyl isocyanide; 7: dppp, tert-butyl isocy-
anide; 8: dppf, tert-butyl isocyanide.
Due to the high polarity the molecules, 6–9 are only very
isocyanide was added. Isocyanide insertion into Pd–C slightly soluble in common solvents and were therefore only
bonds of [(PЈ2)Pd(CH3)(SnB11H11)]– was conducted at characterized by elemental analysis and X-ray structure
room temperature and the insertion products were isolated analysis. In Figures 6, 7, 8, and 9 the structures of the mole-
as zwitterionic molecules with a protonated nitrogen atom cules in the solid state are shown and relevant interatomic
(Scheme 2). The trialkylammonium salt of the stanna-closo- distances and angles are listed. In Table 2 the details of the
dodecaborate [R3NH]2[SnB11H11] cluster serves as the crystal structure analysis are listed. The palladium atoms
source of the protons. In these neutral molecules the coordi- are nearly square-planar-coordinated by the tin, phosphane
nated heteroborate carries the negative charge and the pro- and iminoacyl ligands. The Pd–C distance in complex 6–8
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Eur. J. Inorg. Chem. 2010, 2949–2955

Pd Chemistry with Sn/B Clusters and Isocyanides
is 2.04–2.05 Å long and lies in the range of other iminoacyl
complexes.[14] The Pd–Sn bond length of nearly 2.57 Å in
6–9 is known for other Pd–SnB11H11 complexes.[25]
Figure 9. Molecular structure of [(dppf)Pd(SnB11H11)(CϵN–
C6H11)] (9), H atoms and cations have been omitted for clarity,
ellipsoids with 50%. Interatomic distances [Å] and angles [°]: Sn1–
Pd1 2.5790(5), Pd1–P1 2.342(1), Pd1–P2 2.361(1), C1–Pd1
1.997(6), C1–N1 1.141(8), C1–Pd1–Sn1 81.3(1), C1–Pd1–P2
91.4(1), P1–Pd1–P2 98.47(5), P1–Pd1–Sn1 89.62(4), C1–Pd1–P1
168.3(1), P2–Pd1–Sn1 169.70(4).
Figure 6.
Molecular
structure
of
[(dppe)Pd(SnB11H11)-
{C(Me)=NH-2,6-Me2C6H3}] (6), H atoms have been omitted for
clarity, ellipsoids with 50%. Interatomic distances [Å] and angles
[°]: Sn1–Pd1 2.5819(4), Pd1–P1 2.316(1), Pd1–P2 2.322(1), C2–Pd1
2.052(5), C2–N1 1.277(6), C2–Pd1–P1 96.7(1), P1–Pd1–P2
84.09(4), P2–Pd1–Sn1 93.10(3), C2–Pd1–Sn1 85.7(1), N1–C2–Pd1
121.3(4).
Conclusions
From the reaction of isocyanide complexes of type [cis-
(R–NϵC)2PdCl2] with two equivalents of the tin nucleo-
phile [SnB11H11]2– different reaction products depending on
the substituents at the isocyanide were isolated. trans-Coor-
dinated palladium complexes with isocyanides and tin li-
gands were structurally characterized for the first time.
Furthermore isocyanide insertion into the Pd–C bond was
carried out with complexes [(PЈ2)Pd(CH3)(SnB11H11)]– (PЈ2
= dppe, dppp, dppf) resulting to give zwitterionic molecules
[(PЈ2)Pd(SnB11H11){C(Me)=NH–R}] (R = 2,6-C6H3Me2,
CMe3).
Experimental Section
Figure 7.
Molecular
structure
of
[(dppp)Pd(SnB11H11)-
General: All manipulations were carried out under argon in
Schlenk glassware. Solvents were dried and purified by standard
methods and stored under argon. NMR spectra were recorded with
a Bruker DRX-250 NMR spectrometer equipped with a 5 mm
ATM probe head and operating at 250.13 (1H), 80.25 (11B), 62.90
(13C), 101.25 (31P) and 93.25 MHz (119Sn) and a Bruker DRX-400
NMR spectrometer equipped with a 5 mm QNP (quad nucleus
probe) head and operating at 400.13 (1H) and 100.13 MHz (13C).
Chemical shifts are reported in δ values in ppm relative to external
TMS (1H, 13C), BF3·Et2O (11B), or SnMe4 (119Sn) using the chemi-
{C(Me)=NH–CMe3}] (7), H atoms have been omitted for clarity,
ellipsoids with 50%. Interatomic distances (Å) and angles [°]: Sn1–
Pd1 2.570(1), Pd1–P1 2.333(3), Pd1–P2 2.330(3), C2–Pd1 2.04(1),
C2–N1 1.27(1), C2–Pd1–P1 91.3(3), P1–Pd1–P2 95.4(1), P2–Pd1–
Sn1 89.83(7), C2–Pd1–Sn1 83.1(3), N1–C2–Pd1 129.7(8).
2
cal shift of the solvent H resonance frequency. Elemental analyses
were performed at the Institut für Anorganische Chemie Uni-
versität of Tübingen using a Vario EL analyzer. The infrared spec-
tra were measured on a Bruker Vertex 70 spectrometer equipped
with an ATR unit (attenuated total reflection).
Crystallography: X-ray data for compounds 1–9 were collected with
a Stoe IPDS 2T diffractometer and corrected for Lorentz and po-
larization effects and absorption by air. In the case of compound
4 two orientations (68 and 32%) of the cyclohexyl isocyanide ligand
were found in the crystal structure solution. In Figure 4 the orien-
tation with 68% is shown.
Figure 8.
Molecular
structure
of
[(dppf)Pd(SnB11H11)-
{C(Me)=NH–CMe3}] (8), H atoms have been omitted for clarity,
ellipsoids with 50%. Interatomic distances [Å] and angles [°]: Sn1–
Pd1 2.575(1), Pd1–P1 2.352(3), Pd1–P2 2.359(2), C2–Pd1 2.042(8),
C2–N1 1.28(1), C2–Pd1–P1 90.0(2), P1–Pd1–P2 99.46(8), P2–Pd1–
Sn1 87.51(6), C2–Pd1–Sn1 82.5(2), N1–C2–Pd1 131.2(6).
The programs used in this work were Stoe’s X-Area and WinGX
suite of programs including SHELXS and SHELXL for structure
Eur. J. Inorg. Chem. 2010, 2949–2955
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
2953

M. Hornung, L. Wesemann
FULL PAPER
solution and refinement. Numerical absorption correction based
on crystal-shape optimization was applied for 1–9 with Stoe’s X-
Red and X-Shape.[37–43] Crystal data are listed in Tables 1 and 2.
[(dppp)Pd(SnB11H11){C(Me)=NH–CMe3}] (7): [(dppp)Pd(Me)Cl]
(56.9 mg, 0.10 mmol) and [Et3NH]2[SnB11H11] (45.3 mg,
0.10 mmol) were dissolved in acetonitrile, stirred for 1 h and tert-
butyl isocyanide (11 µL, 0.10 mmol) was added. Crystals were ob-
tained by slow diffusion of ethyl ether into the acetonitrile solution
(58.6 mg, 67.6%). C33H50B11NP2PdSn (866.77): calcd. C 45.73, H
[cis-(R–NϵC)2PdCl2] [R
=
Me3C, C6H11, 2,6-Me2C6H3,
C6H5CH2]: A suspension of PdCl2 and 2 equiv. of isocyanide in
CH3CN were stirred for 24 h. The solvent was removed in vacuo to
give a solid. The products were characterized by IR spectroscopy.
5.81, N 1.62; found C 45.52, H 5.37, N 1.64. IR (ATR): ν = 1574
˜
[s, ν(CϵN)] cm–1.
[Et3MeN]6[Pd(SnB11H11)4] (1): 28.6 mg (0.10 mmol) of [(COD)-
PdCl2] and 192.2 mg (0.40 mmol) [Et3MeN]2[SnB11H11] were al-
lowed to react in 10 mL of CH3CN. Crystals were obtained by slow
diffusion of ethyl ether into the acetonitrile solution: 137.2 mg of
1, 76% yield.
[(dppf)Pd(SnB11H11){C(Me)=NH–CMe3}] (8): [(dppf)Pd(Me)Cl]
(55.5 mg, 0.10 mmol) and [Bu3NH]2[SnB11H11] (62.1 mg,
0.10 mmol) were dissolved in dichloromethane, stirred for 1 h and
tert-butyl isocyanide (11 µL, 0.10 mmol) was added. Crystals were
obtained by slow diffusion of ethyl ether into the dichloromethane
solution (63.6 mg, 63.1%). C40H52B11FeNP2PdSn (1008.71): calcd.
C 47.63, H 5.20, N 1.39; found C 47.15, H 5.04, N 1.18. IR (ATR):
[Et3NH]2[trans-(C6H5CH2–NϵC)2Pd(SnB11H11)2]
(2):
[cis-
(C6H5CH2–NϵC)2PdCl2] (41.2 mg, 0.10 mmol) and [Et3NH]2-
[SnB11H11] (90.5 mg, 0.20 mmol) were dissolved in acetonitrile. Red
crystals were obtained by slow diffusion of ethyl ether into the
acetonitrile solution (63.1 mg, 60.5% yield). C28H68B22N4PdSn2
(1042.56): calcd. C 32.26, H 6.57, N 5.37; found C 32.52, H 6.62,
ν = 1580 [s, ν(CϵN)] cm–1.
˜
[(dppf)Pd(SnB11H11)(CϵN–C6H11)]
(9):
[(dppf)Pd(Me)Cl]
(55.5 mg, 0.10 mmol) and [Bu3NH]2[SnB11H11] (62.1 mg,
0.10 mmol) were dissolved in dichloromethane and cyclohexyl iso-
cyanide (12 µL, 0.10 mmol) was added. Crystals were obtained by
slow diffusion of ethyl ether into the dichloromethane solution
(31.1 mg, 32.5%). C41H50B11FeNP2PdSn (1018,70): calcd. C 48.34,
H 4.95, N 1.37; found C 48.48, H 4.36, N 1.38.
N 5.53. IR (ATR): ν = 2217 [s, ν(CϵN)] cm–1. NMR spectroscopy:
˜
[Bu3NH]2[trans-(C6H5CH2–NϵC)2Pd(SnB11H11)2]: 1H NMR
(CD2Cl2): δ = 7.17–7.38 (m, 10 H, –C6H5), 2.93 (m, 12 H, –N–
CH2–CH2–), 1.64 (m, 12 H, –CH2–CH2–CH2–), 1.31 (m, 12 H,
–CH2–CH2–CH3), 0.88 (m, 18 H, –CH2–CH3) ppm. 11B{1H}
NMR (CD2Cl2): δ = –9.3 (B12), –14.8 (B2–B11) ppm. 13C{1H}
NMR (CD2Cl2): δ = 205.7 (Pd–CϵN–), 128.5, 126.5 (br., –C6H5),
52.1 (–N–CH2–CH2–), 29.8 (N–CH2–C6H5), 24.7 (–CH2–CH2–
CH2–), 19.3 (–CH2–CH2–CH3), 12.7 (–CH2–CH3) ppm. 119Sn{1H}
NMR (CD2Cl2): δ = –307 ppm.
[Bu3MeN][(dppp)Pd(Me)(SnB11H11)]: [(dppp)PdCl(Me)] (56.9 mg,
0.10 mmol) and [Bu3MeN]2[SnB11H11] (64.9 mg, 0.10 mmol) were
dissolved in dichloromethane and stirred for 1 h. The solution was
removed and the yellow residue was washed with water. The pow-
der was dried in vacuo. (69.3 mg, 70.5%). [Bu3MeN][(dppp)-
Pd(Me)(SnB11H11)]·H2O. C41H72B11NOP2PdSn (1001.03): calcd. C
49.19, H 7.25, N 1.40; found C 48.87, H 7.09, N 1.81. NMR spec-
[Bu3NH]2[trans-(Me3C–NϵC)2Pd(SnB11H11)2] (3): The complex
was prepared in the same way as 2. Instead of acetonitrile dichloro-
methane was used (73.3 mg, 64.1% yield). C34H96B22N4PdSn2
(1142.85): calcd. C 35.73, H 8.47, N 4.90; found C 35.88, H 8.47,
1
troscopy [Bu3NH][Pd(dppp)(Me)(SnB11H11)]: H NMR (CD2Cl2):
δ = 7.16–7.72 (m, 20 H, P–C6H5), 3.01 (m, 6 H, –N–CH2–CH2–),
2.65 (m, 2 H, P–CH2–CH2), 2.45 (m, 2 H, P–CH2–CH2) 2.02 (m,
2 H, P–CH2–CH2–CH2–P), 1.73 (m, 6 H, –CH2–CH2–CH2–), 1.40
(m, 6 H, –CH2–CH2–CH3), 0.89 (m, 9 H, –CH2–CH3), 0.58 [t,
3J(31P1H) = 7 Hz, Pd–CH3] ppm. 11B{1H} NMR (CD2Cl2): δ =
–11.0 (B12), –15.2 (B2–B11) ppm. 13C{1H} NMR (CD2Cl2): δ =
125.6–134.7 (m, P–C6H5), 53.2 (–N–CH2–CH2–), 28.9 (d, P–CH2–
CH2), 28.0 (d, P–CH2–CH2), 25.9 (–CH2–CH2–CH2–), 20.5
(–CH2–CH2–CH3), 19.9 (s, P–CH2–CH2–CH2–P), 13.8 (–CH2–
N 4.81. IR (ATR): ν = 2201 [s, ν(CϵN)] cm–1. 1H NMR (CD Cl ):
˜
2
2
δ = 3.03 (m, 12 H, –N–CH2–CH2–), 1.73 (m, 12 H, –CH2–CH2–
CH2–), 1.55 (m, –C–(CH3)3), 1.39 (m, 12 H, –CH2–CH2–CH3),
0.94 (m, 18 H, –CH2–CH3) ppm. 11B{1H} NMR (CD2Cl2): δ =
–9.4 (B12), –15.0 (B2–B11) ppm. 13C{1H} NMR (CD2Cl2): δ =
125.5 (Pd–CϵN–), 60.8 [–N–C(CH3)], 53.3 (–N–CH2–CH2–), 30.1
[–C(CH3)], 25.9 (–CH2–CH2–CH2–), 20.4 (–CH2–CH2–CH3), 13.9
(–CH2–CH3) ppm. 119Sn{1H} NMR (CD2Cl2): δ = –305 [d,
2J(119Sn-117Sn) = 17106 Hz] ppm.
2
CH3), –1.8 [d, J(31P13C) = 88 Hz, Pd–CH3] ppm. 31P{1H} NMR
(CD2Cl2): δ = 14.2 [d, 2J(31P31P, cis) = 53, 2J(119Sn-31P, trans) =
2
2
2584, J(117Sn-31P, trans) = 2474 Hz], –0.3 [d, J(31P31P, cis) = 53,
2J(119Sn-31P, cis) = 343, 2J(117Sn-31P, cis) = 330 Hz] ppm. 119Sn{1H}
[Et4N]4[(C6H11–NϵC)Pd(SnB11H11)3] (4): The complex was pre-
NMR (CD2Cl2): δ = –281 [d, J(119Sn-31P, trans) = 2673 Hz] ppm.
2
pared in the same way as
2
(85.4 mg, 57.6% yield).
C39H124B33N5PdSn3 (1482.76): calcd. C 31.59, H 8.43, N 4.72;
[Bu3MeN][(dppf)Pd(Me)(SnB11H11)]: [(dppf)PdCl(Me)] (65.6 mg,
0.10 mmol) and [Bu3MeN]2[SnB11H11] (64.9 mg, 0.10 mmol) were
dissolved in dichloromethane and stirred for 1 h. The solution was
removed and the yellow residue was washed with water. The pow-
der was dried in vacuo. (82.1 mg, 73.0%). [Bu3MeN][(dppf)-
Pd(Me)(SnB11H11)]·2H2O. C48H76B11FeNO2P2PdSn (1160.98):
calcd. C 49.66, H 6.60, N 1.21; found C 49.90, H 6.59, N 1.71.
found C 31.32, H 8.46, N 4.57. IR (ATR): ν = 2198 [s, ν(CϵN)]
˜
cm–1.
[Me4N]4[(2,6-Me2C6H3–NϵC)Pd(SnB11H11)3] (5): The complex
was prepared in the same way as 2 (74.6 mg, 59.0% yield). [Et4N]4-
[(2,6-Me2C6H3–NϵC)Pd(SnB11H11)3]·Et2O. C45H132B33N5OPdSn3
(1578.89): calcd. C 34.23, H 8.43, N 4.44; found C 34.60, H 8.11,
1
NMR spectroscopy [Bu3NH][(dppf)Pd(Me)(SnB11H11)]: H NMR
N 4.52. IR (ATR): ν = 2193 [s, ν(CϵN)] cm–1.
˜
(CD2Cl2): δ = 7.16–7.52 (m, 20 H, P–C6H5), 3.72–4.63 (m, 8 H, P–
C5H4), 2.94 (m, 6 H, –N–CH2–CH2–), 1.70 (m, 6 H, –CH2–CH2–
CH2–), 1.40 (m, 6 H, –CH2–CH2–CH3), 0.98 (m, 9 H, –CH2–CH3),
0.67 (m, Pd–CH3) ppm. 11B{1H} NMR (CD2Cl2): δ = –15.4 (B2–
B11) ppm. 13C{1H} NMR (CD2Cl2): δ = 125.6–134.3 (m, P–C6H5),
72.5–76.5 (m, P–C5H4), 53.5 (–N–CH2–CH2–), 26.5 (–CH2–CH2–
[(dppe)Pd(SnB11H11){C(Me)=NH-2,6-C6H3Me2}] (6): [(dppe)Pd-
(Me)Cl] (55.5 mg, 0.10 mmol) and [Et3NH]2[SnB11H11] (45.3 mg,
0.10 mmol) were dissolved in acetonitrile, stirred for 1 h and 2,6-
dimethylphenyl isocyanide (13.1 mg, 0.10 mmol) was added. Crys-
tals were obtained by slow diffusion of ethyl ether into the acetoni-
trile solution (54.5 mg, 60.5%). C36H48B11NP2PdSn (900.78): CH2–), 20.5 (–CH2–CH2–CH3), 13.9 (–CH2–CH3), 0.7 [d,
calcd. C 48.00, H 5.37, N 1.55; found C 48.61, H 4.94, N 0.48. IR
2J(31P13C) = 84 Hz, Pd–CH3] ppm. 31P{1H} NMR (CD2Cl2): δ =
2
2
2
(ATR): ν = 1585 [s, ν(CϵN)] cm–1.
31.5 [d, J(31P31P, cis) = 34, J(119Sn–31P, trans) = 2719, J(117Sn–
˜
2954
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© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2010, 2949–2955

Pd Chemistry with Sn/B Clusters and Isocyanides
31P, trans) = 2597 Hz], 16.5 [d, 2J(31P-31P, cis) = 34, 2J(119Sn-31P,
cis) = 372, 2J(117Sn-31P, cis) = 356 Hz] ppm. 119Sn{1H} NMR
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Received: March 15, 2010
Published Online: May 14, 2010
Eur. J. Inorg. Chem. 2010, 2949–2955
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
2955