Interpnictogen compounds with polarised phosphorus-element bonds

Article abstract of DOI:10.1002/zaac.200900564

Metathesis of chloro-substituted N-heterocyclic phosphanes, arsanes, and stibanes with lithium tetraethylphospholide or -arsolide gave interpnictogen compounds 2-4 with As-P or Sb-P bonds, respectively. The products were characterised by analytical and sp

Full text of DOI:10.1002/zaac.200900564

ARTICLE
DOI: 10.1002/zaac.200900564
Interpnictogen Compounds with Polarised Phosphorus–Element Bonds
Sebastian Burck,[a] Martin Nieger,[b] and Dietrich Gudat*[a]
Dedicated to Professor Gerd Becker on the Occasion of His 70th Birthday
Keywords: N-heterocyclic compounds; Interpnictogen bonds; Donor-acceptor systems; Phosphorus; Pnictogens
Abstract. Metathesis of chloro-substituted N-heterocyclic phosphanes, bond lengths, and the As–P bond in the isomers 2 and 3 which are
arsanes, and stibanes with lithium tetraethylphospholide or -arsolide merely distinguished by formal exchange of the pnictogen atoms be-
gave interpnictogen compounds 2–4 with As–P or Sb–P bonds, respec- tween both rings differ by some 4 pm. The observed structural features
tively. The products were characterised by analytical and spectroscopic suggest that compounds 2–4 may, like the corresponding diphos-
data and single-crystal X-ray diffraction studies. All compounds fea- phanes, be perceived as adducts of Lewis-pairs which are held together
ture central E–E' bonds that are notably longer (5–12 %) than standard by a dative interpnictogen bond.
expected that the ionic character is further enhanced if one or
Introduction
both phosphorus atoms in I are formally replaced by an ar-
senic, antimony or bismuth atom. Unsymmetrical derivatives
resulting from formal substitution of just one phosphorus atom
in I are in this respect of particular interest as compounds with
bonds between unlike pnictogen atoms are much less explored
than derivatives with homonuclear bonds [4], and formal sub-
stitution of either of the two inequivalent phosphorus atoms of
I may give rise to structural isomers where the bond polarisa-
tion implied by the bond/no bond resonance depicted in
Scheme 1 is either enhanced or offset by the electronegativity
difference between the bonding partners. As a consequence,
the balance of both factors may affect the actually observable
bond lengthening in the two isomeric molecules and thus con-
stitute a special type of bond length isomerism. Following this
outline, we report on the synthesis and structural characterisa-
tion of analogous compounds where both rings are linked by
an As(δ+)–P(δ–), Sb(δ+)–P(δ–), or P(δ+)–As(δ–) interpnictogen bond.
Unsymmetrically substituted diphosphanes I (Scheme 1),
which consist of an N-heterocyclic 1,3,2-diazaphospholene and
a phosphole fragment are distinguished by unusually long P–
P bonds whose distances (2.35–2.70 Å) exceed by far the
standard single bond length of 2.21 Å [1], and a unique react-
ivity that enables these species to undergo insertion or addition
reactions with concomitant cleavage of the P–P bond under
extremely mild conditions [1, 2]. The structural and chemical
properties have been attributed to a bonding situation which
has been characterised in terms of bond/no bond resonance
between covalent (IA) and ionic (IB) canonical structures, and
led to describe diphosphanes I as Lewis-acid/base complexes
with dative P–P interactions rather than molecules which are
formally assembled by connecting two radical fragments with
a covalent bond [1].
Results and Discussion
Diphosphane 1 is formed through metathesis between N-het-
erocyclic chlorophosphane 5a and lithium phospholide 6a [1].
By analogy, coupling of 6a with chloroarsane 5b [5] and chlo-
rostibane 5c [5] gave the expected products 2, 3 with As–P
and Sb–P bonds, and treatment of 5a with lithium arsolide 6b
[6] produced 4 which is set apart from 2 by formal exchange
of the two pnictogen atoms (Scheme 2). In contrast, reaction
of chlorophosphane 5a with the potassium stibolide
[K(SbC4Et4)] (6c) [7] was found to be messy, and we were
unable to obtain an isolable product. The interpnictogen com-
pounds 2–4 were isolated in moderate to good yields of 50–
72 % and characterised by analytical and spectroscopic data
and single-crystal diffraction studies.
Scheme 1.
Regarding that bond energies decrease continually for cova-
lent E–E bonds between the heavier pnictogen atoms [3], it is
* Prof. Dr. D. Gudat
Fax: +49-711-685-64241
E-Mail: gudat@iac.uni-stuttgart.de
[a] Institut für Anorganische Chemie
Universität Stuttgart
Pfaffenwaldring 55
70550 Stuttgart, Germany
[b] Laboratory of Inorganic Chemistry
University of Helsinki
A. I. Virtasen aukio 1
Helsinki, Finland
Z. Anorg. Allg. Chem. 2010, 636, 1263–1267
© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
1263

S. Burck, M. Nieger, D. Gudat
ARTICLE
Scheme 2.
The spectroscopic data of 2–4 are unpeculiar. The 31P NMR
chemical shifts of 2 (δ31P = 26.9) and 3 (δ31P = 25.4) match
closely the shift of the phosphorus atom in the phosphole ring
of 1 (δ31P = 23.1 [1]). The 31P NMR signal of 4 (δ31P = 160.1)
is deshielded with respect to the corresponding resonance in 1
(δ31P = 147.1) but lies still in the region between 135 and
170 ppm [1] covered by the chemical shifts of known diphos-
phanes (I). Mass spectra of 2–4 show molecular ion peaks of
very low intensity (0.1–0.6 %) which indicate that the intact
molecular species exist in the gas phase but have quite low
stability, and the appearance of characteristic fragment ions
attributable to N-heterocyclic cations [(CH)2(NMes)2E]+ and
ions [C12H19E]+ (E = P, As) suggests cleavage of the central
P–E bond as a prominent pathway for fragmentation.
Figure 2. ORTEP-style representation of a molecule of 3 in the crystal
(hydrogen atoms omitted for clarity; displacement parameters drawn
at 50 % probability level). Selected bond lengths /Å and angles /° are
listed in Table 1.
Compounds 2 and 3 crystallise in the monoclinic space
group P21/n (2) or P21/c (3), respectively, and show the same
pattern for the packing of individual molecules in the crystal
whereas crystals of 4 are triclinic and belong to the same space
¯
group P1 as 1 [1]. Closer inspection reveals that single mole-
cules of 1, 2–4 are distinguished by subtle differences in the
conformation of ethyl substituents at the phosphole ring (cf.
Figure 1, Figure 2, and Figure 3) which alter the overall mo-
lecular shape and are presumably responsible for the observed
differences in the crystal packing.
Figure 3. ORTEP-style representation of a molecule of 4 in the crystal
(hydrogen atoms omitted for clarity; displacement parameters drawn
at 50 % probability level). Selected bond lengths /Å and angles /° are
listed in Table 1.
the individual N–C, C–C and P–C bonds are essentially identi-
cal within experimental error and do not deviate significantly
from the corresponding bond lengths in diphosphanes I. The
As–N bonds in 2 and the Sb–N bonds in 3 are by some 5–
6 pm longer than those in 2-halogeno-substituted N-heterocy-
clic arsanes (As–N 1.805–1.806 Å [5]) or stibanes (Sb–N
1.998–2.000 Å [5]), respectively. The same trend has also been
noted for the P–N bond lengths in I [1] and was interpreted as
indication of a more severe bond order alternation, and thus a
lesser π-electron delocalisation, than in the 2-chloro deriva-
tives. The As–C distances in the arsole ring of 4 (1.911–
1.916 Å) are similar to those in known arsoles or η1-arsole
complexes (As–C 1.91–1.94 Å [8]), and the bond length distri-
bution in this ring suggests that the π-electron structure is like
in 1 closer to that of a conjugated diene rather than a delocal-
Figure 1. ORTEP-style representation of a molecule of 2 in the crystal
(hydrogen atoms omitted for clarity; displacement parameters drawn
at 50 % probability level). Selected bond lengths /Å and angles /° are
listed in Table 1.
Comparison of significant bond lengths of 2–4 with each
other and with the appropriate data for 1 (Table 1) reveals that ised aromatic heterocycle.
1264
www.zaac.wiley-vch.de
© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2010, 1263–1267

Interpnictogen Compounds with Polarised Phosphorus–Element Bonds
Table 1. Selected bond lengths /Å and angles /° for 2–4. Data for 1
together by a dative donor-acceptor interaction rather than a
genuine covalent bond. The notable deviation in the P–As dis-
tances in the isomers 2 and 4 may then be traced to the higher
Lewis-acidity of the N-heterocyclic arsenium as compared to
the corresponding phosphenium cation [5], however, regarding
that very minute energetic forces suffice to induce far larger
variations of P–P distances in I [1], the difference must be
regarded as chemically insignificant. The trend in Lewis-acidi-
ties of the cation fragments can likewise serve to explain the
effect that the relative bond lengthening (i.e. the difference be-
tween actually observed E–E' distances in 1, 2 and 3 and the
appropriate standard bond lengths) shrinks with increasing
atomic number of the pnictogen atom in the cation fragment
although, in view of the importance of steric effects for the
molecular structures of I [1], it must be conceded that part of
this effect is also attributable to a decrease of repulsive interac-
tions between substituents with increasing atomic radius of the
central pnictogen atoms.
[1] are included for comparison.
a)
1
2
3
4
E···E'
P1–P2
As1–P1
Sb1–P1
P1–As1
E–E'
2.484(1)
1.722(2)
1.404(2)
1.327(3)
1.397(3)
1.716(2)
1.789(2)
1.371(3)
1.446(3)
1.371(3)
1.788(2)
2.554(1)
1.867(2)
1.385(3)
1.334(3)
1.403(3)
1.862(2)
1.791(3)
1.375(3)
1.455(3)
1.376(3)
1.791(3)
2.667(2)
2.054(3)
1.398(6)
1.328(7)
1.391(6)
2.053(4)
1.782(5)
1.369(7)
1.428(7)
1.369(7)
1.785(6)
2.588(1)
1.725(3)
1.399(3)
1.309(4)
1.411(4)
1.716(2)
1.911(3)
1.371(4)
1.454(5)
1.364(5)
1.916(3)
E–N2
N2–C3
C3–C4
C4–N5
N5–E
E'–C24
C24–C25
C25–C26
C26–C27
C27–E'
C24–E'–E
C27–E'–E
N2–E–E'
N5–E–E'
81.1(1)
81.9(1)
109.7(1)
110.9(1)
79.0(1)
81.2(1)
110.8(1)
109.2(1)
79.3(2)
79.8(2)
105.9(1)
108.6(1)
79.1(1)
80.0(1)
108.6(1)
110.4(1)
a) Data from ref. [1]
Conclusions
Higher congeners of diphosphanes with interpnictogen E–E'
bonds were prepared in a controlled way by metathesis reac-
tions. The results of single-crystal X-ray diffraction studies re-
veal that the E–E' bonds are longer than standard distances and
show a certain elasticity which is highlighted by the observed
deviation of As–P distances in the isomers 2, 4. The structural
features suggest to perceive the molecules, like the analogous
diphosphanes, as donor-acceptor adducts of Lewis-pairs that
are held together by dative E–E' bonds.
The most interesting structural parameters are beyond doubt
the E–E' distances of the bonds connecting the two pnictogen
atoms. Like in the diphosphanes I, the As–P and Sb–P bonds
in 2–4 are generally longer than standard bond lengths (As–P
2.338 0.023 Å, Sb–P 2.541 0.026 Å [9]) but the relative
lengthening decreases continually from 1, where the distance
of 2.484 Å exceeds a standard bond length by 12 %, to 9 %
for the As–P bonds in 2 and 4 and 6 % for the Sb–P bond in
3. The same trend had previously been observed in a series of
2-chloro-substituted N-heterocyclic phosphanes and their
heavier congeners [5] and owes presumably to the fact that the
standard values reflect with growing electronegativity differ-
ence of E and E' likewise an increasing ionicity so that these
systems are therefore getting more similar (ionic) to the re-
ported molecules and, as a consequence, the deviations become
smaller. The P–As bonds in the isomers 2 and 4 differ by a
margin of 3.5 pm which exceeds appreciably the sum of esti-
mated errors. It is further an interesting aspect to note that the
C–E2–E1 bond angles in 2–4 (79–82°) lie right through at the
lower end of the range found for diphosphanes I (79–89°) [1]
and impose therefore a molecular conformation in which the
pnictogen atom in the EN2C2-ring resides above the EC4-ring
and is close to its centroid. The EC4-rings deviate not signifi-
cantly from planarity and the EN2C2-rings display very flat
Experimental Section
General remarks: All manipulations were carried out under argon
using Schlenk techniques. Solvents were dried prior to use by common
procedures. NMR spectra were recorded with Bruker Avance 250 (1H:
250.1 MHz, 13C: 62.8 MHz, 31P: 101.2 MHz) or Avance 400 (1H:
400.1 MHz, 13C: 100.6 MHz, 31P: 161.9 MHz) spectrometers at
303 K. Chemical shifts were referenced to ext. TMS (1H, 13C) or 85 %
H3PO4 (Ξ = 40.480747 MHz, 31P). EI-MS: Varian MAT 711, 70eV.
Elemental analysis: Perkin–Elmer 24000 CHN/O Analyser. Melting
points were determined in sealed capillaries.
General Procedure for the Reaction of 5b,c with Lithium-tet-
raethylphospholide
Lithium shavings (14 mg, 2.0 mmol) were added to a solution of 1-
envelope conformations (fold angles between C2N2 and N2E- chloro-2,3,4,5-tetraethylphosphole [10] (230 mg, 1.0 mmol) in THF
(20 mL) and the mixture was allowed to stir for 3 h at ambient temper-
ature. Unreacted lithium was removed by filtration and the solution
added dropwise to a cooled (–78 °C) solution of 5b [5] (403 mg,
1.0 mmol) or 5c [5] (450 mg, 1.0 mmol) in THF (50 mL). The mixture
was allowed to warm to room temperature and stirred for 1 h. Solvent
was removed under reduced pressure and the residue dispersed in hex-
ane (100 mL). Precipitated salts were removed by filtration through
Celite. The volume of the filtrate was reduced to 20 mL under reduced
pressure and the remaining solution stored at –20 °C for crystallisation.
The yellow crystalline precipitate was collected by filtration and dried
units 5.5–7.5°). The five-membered rings in 2–4 exhibit angles
of 34–40° between least-squares planes drawn through the at-
oms in each ring.
The presence of lengthened and highly flexible P–P bonds
in combination with acute phosphorus bond angles was identi-
fied as characteristic structural signature of the special bonding
situation in diphosphanes I that led to perceive these com-
pounds as phosphenium–phospholide contact ion pairs [1]. As
compounds 2–4 display essentially the same features, we con-
sider them likewise as adducts of Lewis pairs that are held in vacuo.
Z. Anorg. Allg. Chem. 2010, 1263–1267
© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.zaac.wiley-vch.de
1265

S. Burck, M. Nieger, D. Gudat
ARTICLE
1,3-Di-mesityl-2-(2',3',4',5'-tetraethylphospholyl)-1,3,2-di-
azaarsolene (2): Yield 347 mg (0.62 mmol, 62 % yield); m.p. 162 °C.
C32H44AsN2P (562.61): calcd. C 68.32 H 7.88 N 4.98; found C 68.03
X-ray Crystallography
The crystals were investigated with a Nonius Kappa-CCD diffractome-
ter at 123(2) K using Mo-Kα radiation (λ = 0.71073 Å). Direct Methods
(SHELXS-97 [12]) were used for structure solution and full-matrix
least-squares refinement on F2 (SHELXL-97 [12]). Hydrogen atoms
were localised by difference Fourier synthesis and refined using a rid-
ing model.
1
H 7.96 N 4.69 %. H NMR (C6D6): δ = 6.80 (s, 4 H, m-CH), 6.06 (s,
2 H, N–CH), 2.41 (s, 12 H, o-CH3), 2.35 (q, 4 H, 3JHH = 7,6 Hz, CH2),
2.14 (s, 6 H, p-CH3), 1.98 (qd, 2 H, 2JHH = 14.0, 3JHH = 7.6 Hz, CH2);
2
3
3
1.40 (qd, 2 H, JHH = 14.0, JHH = 7.6 Hz, CH2), 1.05 (t, 6 H, JHH
=
7.6 Hz, CH3), 1,04 (t, 6 H, JHH = 7.6 Hz, CH3). 13C{1H} NMR
3
2
1
(C6D6): δ = 151.9 (d, JPC = 3.4 Hz, CPhosphole), 144.9 (d, JPC
=
2: orange crystals, C32H44AsN2P, M = 562.58, crystal size 0.30 × 0.20
× 0.10 mm, monoclinic, space group P21/n (No. 14), a = 8.1286(2) Å,
27.6 Hz, CPhosphole), 139.7 (d, 3JPC = 1.5 Hz, i-C), 136.4 (s, p-C), 135.8
4
3
(d, JPC = 1.5 Hz, o-C), 129.8 (s, m-CH), 122.4 (d, JPC = 1.4 Hz, N–
b
= 20.5683(5) Å, c = 18.1360(4) Å, β = 100.036(1)°, V =
CH), 21.4 (d, 3JPC = 1.0 Hz, CH3), 21.3 (d, 3JPC = 22.4 Hz, CH2), 21.0
2985.79(12) Å3, Z = 4, ρ(calcd) = 1.252 Mg·m–3, F(000) = 1192, μ =
1.21 mm–1, 14695 reflexes (2θmax = 50°), 5258 unique [Rint = 0.050],
semi-empirical absorption correction from multiple reflections, max.
and min. transmission 0.7959 and 0.7220, 331 parameters, R1 [I >
2σ(I)) = 0.033, wR2 (all data) = 0.070, GooF = 0.93, largest diff. peak
and hole 0.403 and –0.354 e·Å–3.
2
(s, CH3), 19.9 (s, o-CH3), 19.8 (s, o-CH3), 18.6 (d, JPC = 6.8 Hz,
CH2), 17.8 (s, CH3). 31P{1H} NMR (C6D6): δ = 26.9 (s). MS: (EI,
70 eV, 420K): m/e (%) = 562.1 ([M]+, 0.5), 488.2 ([M–C5H14]+, 0.6);
367.0 ([M–C12H20P]+, 24), 277.1 ([M–C13H23PAs]+, 100), 194.0 ([M–
C20H25N2As]+, 54).
3: red crystals, C32H44N2PSb, M = 609.41, crystal size 0.20 × 0.10 ×
0.05 mm, monoclinic, space group P21/c (No. 14), a = 8.5475(3) Å,
1,3-Di-mesityl-2-(2',3',4',5'-tetraethylphospholyl)-1,3,2-di-
azastibolene (3): Yield 303 mg (0.50 mmol, 50 % yield); m.p.
159 °C. C32H44N2PSb (609.44): calcd. C 63.07 H 7.28 N 4.60, found
b
= 20.7642(7) Å, c = 17.6826(7) Å, β = 103.865(1)°, V =
3046.90(19) Å3, Z = 4, ρ(calcd) = 1.329 Mg·m–3, F(000) = 1264, μ =
0.98 mm–1, 13737 reflexes (2θmax = 50°), 5369 unique [Rint = 0.055],
semi-empirical absorption correction from equivalents, max. and min.
transmission 0.9498 and 0.7952, 331 parameters, 18 restraints, R1 [I
> 2σ(I)) = 0.045, wR2 (all data) = 0.119, GooF = 0.97, largest diff.
peak and hole 1.261 and –1.290 e·Å–3.
1
C 62.94 H 7.28 N 4.59 %. H NMR (C6D6): δ = 6.84 (s, 4 H, m-CH),
3
6.37 (s, 2 H, N–CH), 2.46 (s, 12 H, o-CH3), 2.28 (q, 4 H, JHH
=
=
3
3
7.5 Hz, CH2), 2.18 (s, 6 H, p-CH3), 1.58 (qd, 4 H, JH3H = 7.5, JPH
3
4.7 Hz, CH2), 1.00 (t, JHH = 7.5 Hz, CH3), 0.97 (t, JHH = 7.5 Hz,
CH3). 13C{1H} NMR (C6D6): δ = 146.8 (d, JPC = 3.7 Hz, CPhosphole),
2
1
3
139.2 (d, JPC = 29.5 Hz, CPhosphole), 137.2 (d, JPC = 1.3 Hz, i-C),
129.7 (s, o-C), 124.4 (s, m-CH), 124.4 (s, p-C), 119.3 (d, 3JPC = 1.3 Hz,
N–CH), 16.8 (s, CH3), 16.1 (d, 2JPC = 12.9 Hz, CH2), 15.5 (s, o-CH3),
14.6 (d, JPC = 2.9 Hz, CH2), 12.9 (s, CH3), 12.8 (d, JPC = 1.0 Hz,
CH3). 31P{1H} NMR (C6D6): δ = 25.4 (s). MS: (EI, 70 eV, 420K):
m/e (%) = 608.2 ([M]+, 0.6), 413.0 ([M–C12H20P]+, 16), 277.0 ([M–
C21H23PSb]+, 100), 194.0 ([M–C20H25N2Sb]+, 74).
4: yellow crystals, C32H44AsN2P, M = 562.58, crystal size 0.15 × 0.10
¯
× 0.03 mm, triclinic, space group P1(No. 2): a = 8.1693(3) Å, b =
3
3
8.9044(3) Å, c = 20.4802(8) Å, α = 96.304(2)°, β = 90.302(2)°, γ =
94.501(2)°, V = 1476.07(9) Å3, Z = 2, ρ(calcd) = 1.266 Mg·m–3,
F(000) = 596, μ = 1.23 mm–1, 12039 reflexes (2θmax = 50°), 5354
unique [Rint = 0.081], semi-empirical absorption correction from equiv-
alents, max. and min. transmission 0.9619 and 0.8005, 331 parameters,
R1 [I > 2σ(I)) = 0.048, wR2 (all data) = 0.078, GooF = 0.86, largest
diff. peak and hole 0.530 and –0.405 e·Å–3.
1,3-Di-mesityl-2-(2',3',4',5'-tetraethylarsolyl)-1,3,2-di-
azaphospholene (4): Potassium shavings (390 mg, 10 mmol) were
added to a solution of 1-chloro-2,3,4,5-tetraethylarsole [10] (1.37 g,
5.0 mmol) in THF (20 mL) and the mixture was allowed to stir for 5
d at ambient temperature. Unreacted metal was removed by filtration
and the solution added dropwise to a cooled (–78 °C) solution of 5a
[11] (1.80 g, 5.0 mmol) in THF (50 mL). The mixture was allowed to
warm to room temperature and stirred for 1 h. Solvent was removed
under reduced pressure and the residue dispersed in hexane (100 mL).
Precipitated salts were removed by filtration through Celite. The vol-
ume of the filtrate was reduced to 20 mL under reduced pressure and
the remaining solution stored at –20 °C for crystallisation. The orange
crystalline precipitate was collected by filtration and dried in vacuo to
give 1.97 g (3.5 mmol, 70 % yield) of 4 of m.p. 178 °C. C32H44AsN2P
(562.61): calcd. C 68.32 H 7.88 N 4.98; found C 67.99 H 7.91 N 4.60
Crystallographic data (excluding structure factors) for the structure re-
ported in this work have been deposited with the Cambridge Crystallo-
graphic Data Centre as supplementary publication no. CCDC-757208
(2), -757209 (3), 757210 (4). Copies of the data can be obtained free
of charge on application to The Director, CCDC, 12 Union Road, Cam-
bridge DB2 1EZ, UK (Fax: int.code+44-1223-336-033; E-Mail: de-
posit@ccdc.cam.ac.uk).
References
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Götz, M. Kaupp, M. Nieger, J. Weber, J. Schmedt auf der Günne,
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[2] S. Burck, D. Gudat, M. Nieger, Angew. Chem. 2007, 119, 2977–
2980; Angew. Chem. Int. Ed. 2007, 46, 2919–2922; I. Hajdók, F.
Lissner, M. Nieger, S. Strobel, D. Gudat, Organometallics 2009,
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[3] R. Steudel in Chemie der Nichtmetalle, 2nd Ed., Walter de Gru-
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1
%. H NMR (C6D6): δ = 6.77 (s, 4 H, m-CH), 5.84 (s, 2 H, N–CH),
3
2.43 (s, 6 H, p-CH3), 2.33 (q, 4 H, JHH = 7.3 Hz, CH2), 2.01 (q, 4 H,
3
3JHH = 7.3 Hz, CH2), 1.23 (s, 12 H, o-CH3), 1.06 (t, 6 H, JHH
=
7.3 Hz, CH3), 0.88 (t, 6 H, JHH = 7.3 Hz, CH3). 13C{1H} NMR
3
(C6D6): δ = 152.0 (d, 2JPC = 14.7 Hz, CArsole), 143.4 (d, 3JPC = 8.2 Hz,
2
5
CArsole), 136.6 (d, JPC = 6.8 Hz, i-C), 136.4 (d, JPC = 2.0 Hz, p-C),
135.8 (d, 3JPC = 3.4 Hz, o-C), 129.7 (d, 4JPC = 1.1 Hz, m-C), 121.4 (d,
2JPC = 8.9 Hz, N–CH), 22.7 (s, p-CH3), 20.7 (d, JPC = 0.8 Hz, CH3),
5
3
4
19.7 (d, JPC = 5.5 Hz, CH2), 18.8 (d, JPC = 2.2 Hz, CH2), 16.6 (d,
4JPC = 1.4 Hz, CH3), 14.0 (s, o-CH3). 31P{1H} NMR (C6D6): δ = 160.6
(s). MS: (EI, 70 eV, 430K): m/e (%) = 562.0 ([M]+, 0.1), 478.0 ([M–
C6H12]+, 31), 323.1 ([M–C12H20As]+, 27), 238.0 ([M–C20H42N2P]+,
100).
[4] For some new developments see: E. Conrad, N. Burford, R.
McDonald, M. J. Ferguson, Inorg. Chem. 2008, 47, 2952–2954;
E. Conrad, N. Burford, R. McDonald, M. J. Ferguson, J. Am.
Chem. Soc. 2009, 131, 5066–5067.
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© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2010, 1263–1267

Interpnictogen Compounds with Polarised Phosphorus–Element Bonds
[5] T. Gans-Eichler, D. Gudat, M. Nieger, Heteroatom Chem. 2005,
16, 327–338.
Sb; X = any non-metal) with three-coordinate P and E atoms. The
given values are the mean value and standard deviation of a sam-
ple of 8 (for E = As) or 9 compounds (for E = Sb), respectively.
[10] M. Westerhausen, C. Gückel, H. Piotrowski, P. Mayer, M. Warch-
hold, H. Nöth, Z. Anorg. Allg. Chem. 2001, 627, 1741–1750.
[11] S. Burck, D. Gudat, M. Nieger, W. W. du Mont, J. Am. Chem.
Soc. 2006, 128, 3946–3955.
[6] M. Westerhausen, M. W. Ossberger, P. Mayer, H. Piotrowski, H.
Nöth, Organometallics 2004, 23, 3417–3424.
[7] M. Westerhausen, C. Guckel, M. Warchhold, H. Nöth, Organome-
tallics 2000, 19, 2393–2396.
[8] A. J. Ashe, W. M. Butler, T. R. Diephouse, Organometallics
1983, 2, 1005; M. Ma, S. A. Pullarkat, Y. Li, P.-H. Leung, Inorg.
Chem. 2007, 46, 9488; M. Ma, S. A. Pullarkat, Y. Li, P.-H. Leung,
J. Organomet. Chem. 2008, 693, 3289.
[12] G. M. Sheldrick, Acta Crystallogr., Sect. A 2008, 64, 112.
Received: December 14, 2009
Published Online: February 11, 2010
[9] Result of a query in the CSD database (version 5.31 of Nov. 2009)
for compounds featuring the generic fragment X2P–EX2 (E = As,
Z. Anorg. Allg. Chem. 2010, 1263–1267
© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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