Metalated diphosphanylsiloxanes with polycyclic and polymeric structures

Article abstract of DOI:10.1016/j.jorganchem.2006.12.005

The reactions of the diphosphanylsiloxane O(SiiPr₂PH₂)₂ (1) with MiPr₃ (M = Ga, In) produced the polycyclic compounds [O{SiiPr₂(PH)MiPr₂}{SiiPr₂(P)MiPr}] ₂ (2, 3). Compounds 2 and 3 are composed of three M₂P₂ rings forming a ladder structure and two OSi₂P₂M rings. By reactions of 1 with n-BuLi the polymeric compound [O(SiiPr₂PHLi)₂(THF)(TMEDA)] · THF (4) was obtained.

Full text of DOI:10.1016/j.jorganchem.2006.12.005

Journal of Organometallic Chemistry 692 (2007) 2780–2783
www.elsevier.com/locate/jorganchem
Metalated diphosphanylsiloxanes with polycyclic
and polymeric structures
*
Carsten von Ha¨nisch , Sven Stahl
Institut fu¨r Nanotechnologie, Forschungszentrum Karlsruhe, Postfach 3640, D-76021 Karlsruhe, Germany
Received 10 August 2006; received in revised form 30 November 2006; accepted 3 December 2006
Available online 9 December 2006
Abstract
The reactions of the diphosphanylsiloxane O(SiiPr2PH2)2 (1) with MiPr3 (M = Ga, In) produced the polycyclic compounds
[O{SiiPr2(PH)MiPr2}{SiiPr2(P)MiPr}] (2, 3). Compounds 2 and 3 are composed of three M2P2 rings forming a ladder structure and
2
two OSi2P2M rings. By reactions of 1 with n-BuLi the polymeric compound [O(SiiPr2PHLi)2(THF)(TMEDA)] Æ THF (4) was obtained.
Ó 2006 Elsevier B.V. All rights reserved.
Keywords: Silicon; Phosphorus; Gallium; Indium; Polycyclic compounds
1. Introduction
2. Results and discussion
During the last decade several groups have investigated
metalation reactions of primary silylphosphines (R3SiPH2)
[1,2]. These reactions yield ring or cage compounds. We are
engaged in metalation reactions of diphosphanylsilanes
(R2Si(PH2)2) as well as diphosphanylsiloxanes (O(SiR2
PH2)2). From such reactions some unusual polycyclic com-
pounds can be obtained [3,4]. Recently, we synthesized for
example the compounds [O(SiiPr2PHMEt2)2]4 by the reac-
tion of O(SiiPr2PH2)2 (1) with MEt3 (M = Al, Ga). These
compounds show a 16-membered M8P8 ring as structural
motif (see Scheme 1) [4].
The sterically more demanding GaiPr3 instead of GaEt3
reacts with 1 at 70 °C to form the polycyclic compound 2.
Single crystals of 2 can be obtained by recrystallization of
the crude product from heptane. The analogous indium
compound 3 can be synthesized by the reaction of 1 with
IniPr3. The product of the reaction of 1 with n-BuLi is
the polymeric Li–P chain compound [O(SiiPr2PHLi)2
(THF)(TMEDA)] Æ THF (4).
The centrosymmetric compound 2 crystallizes in the
monoclinic space group P21/n [5]. The molecule consists
of a Ga4P4-ladder arrangement. Adjacent phosphorus
atoms are bridged by SiiPr2–O–SiiPr2 units resulting in a
pentacyclic core structure composed of three Ga2P2 rings
and two OSi2P2Ga rings. The three Ga2P2 rings are in
chair-conformation with the SiiPr2–O–SiiPr2 bridges
located above and under this moiety. On the Ga atoms
of the central Ga2P2 ring (Ga(1) and Ga(10)) one isopropyl
group is retained, whereas on Ga(2) and Ga(20) two unre-
acted isopropyl groups remain. Consequently each one
hydrogen substituent is retained at the outer P atoms.
These hydrogen atoms were located in the fourier map.
In the infra-red spectrum of 2 a band observed at
2324 cmꢀ1 can be assigned to the P–H stretch vibration.
The 31P{1H} NMR spectrum consists of two multiplet res-
onances for the two different phosphorus positions in 2 at
ꢀ216.9 and ꢀ244.2 ppm (AA0XX0 spin system). In the 31P
NMR spectrum the signal at d = ꢀ244.2 shows a 1JPH cou-
pling (260 Hz). Therefore, this signal can be assigned to the
outer P atoms (P(1) and P(10) in Fig. 1). The Ga–P bond
lengths within 2 are in the range of 238.4–249.6 pm. The
longest Ga–P bond can be observed at the outer end of
*
Corresponding author. Tel./fax: +49 7247 82 6368.
E-mail address: carsten.vonhaenisch@int.fzk.de (C. von Ha¨nisch).
0022-328X/$ - see front matter Ó 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2006.12.005

C. von Ha¨nisch, S. Stahl / Journal of Organometallic Chemistry 692 (2007) 2780–2783
2781
iPr2Si
SiiPr2
MEt2
O
O
P
P
H
H
SiiPr2
iPr2Si
Et2M
MEt2
P
P
P
P
iPr
iPr
iPr
iPr
R = Et;
M = Al, Ga
H
H
H
H
O
Si
Si
PH2
MEt2
Et2M
- C2H6
H2P
1
+ MR3
Et2M
P
MEt2
P
SiiPr2
iPr2Si
H
H
R = iPr;
M = Ga, In
- C3H8
O
O
MEt2
iPr2Si
SiiPr2
O
SiiPr2
P
iPr2Si
iPr
MiPr2
H
P
M
P
M
P
H
iPr2M
2: M = Ga
3: M = In
iPr
SiiPr2
iPr2Si
O
O
L
iPr2Si
SiiPr2
P
THF
Li
1. + 2 nBuLi
2. + TMEDA (= L)
3. + THF
H
Li
iPr
iPr
iPr
iPr
H
O
P
P
P
Si
H2P
Si
PH2
Li
H
Li
L
H
THF
iPr2Si
SiiPr2
4
O
Scheme 1. Metalation reactions of the diphoshpanylsiloxane O(SiiPr2PH2)2 (1).
the ladder structure (Ga(2)–P(1)), whereas the Ga(1)–P(2)
bond is considerably shorter (238.4 pm). Other cyclic or
polycyclic Ga/P compounds exhibit Ga–P bond lengths
in the range of 234–250 pm [6].
meric Li–P chain. The bridging Li ion is coordinated by
an additional THF ligand, resulting in a distorted trigonal
planar coordination geometry. Pairs of phosphorus atoms
of the Li–P chain are bridged by SiiPr2–O–SiiPr2 groups
above and below the chain in alternating fashion. The
Li–P bonds are 248.8 and 253.1 pm long. These values
are almost in the range of Li–P bond lengths observed in
other chain like LiPR2 compounds (249–266 pm) [7].
Currently, we investigate reactions of 1 with metal
amides, metal alkoxides and metal alkyl compounds.
Moreover, we study the synthetic potential of compound
4, in particular the incorporation of O(SiR2PH)2 fragments
in cyclic ligands.
The molecular structure of the indium compound 3 is
almost identical with the structure of 2. Compound 3 crys-
ꢀ
tallizes in the triclinic space group P1 [5]. The In–P bond
distances observed in
3 are between 255.9(2) and
269.4(2) pm.
The reaction of 1 with 2 equiv. of n-BuLi in heptane
yields a colourless microcrystalline precipitate. A clear
solution can be obtained by subsequent addition of
TMEDA and THF. Colourless needle-shaped crystals
precipitate from this solution at 6 °C. The X-ray analysis
of these crystals revealed the composition [O(SiiPr2PHLi)2
(THF)(TMEDA)] Æ THF (4) [5] (see Fig. 2). Compound 4
crystallizes in the tetragonal space group Ibca and exists
as a polymer in the solid state. The phosphanyl groups
of the starting material are lithiated. One of the lithium
ions is coordinated by both phosphorus atoms of one
diphosphanylsiloxane fragment. A six-membered, slightly
twisted heterocycle of the element combination OSi2P2Li
is formed. This lithium ion is further coordinated by a
TMEDA ligand resulting in a distorted tetrahedral coordi-
nation environment. The second lithium ion in 4 has a
bridging position between two rings resulting in a poly-
3. Experimental
All manipulations were carried out under rigorous
exclusion of oxygen and moisture using a Schlenk line
and nitrogen atmosphere. Solvents were dried and freshly
distilled before use. [O(SiiPr2PH2)2] (1) was prepared
according to a published procedure [4]. n-BuLi (1.6 M solu-
tion in hexane) was obtained from Aldrich. GaiPr3 and
IniPr3 were prepared by Grignard reactions starting from
MCl3 (M = Ga, In) and iPrMgCl as described in the liter-
ature [8]. The 31P NMR spectra were recorded on a Bruker
Avance 300 spectrometer. A summary of the crystallo-

2782
C. von Ha¨nisch, S. Stahl / Journal of Organometallic Chemistry 692 (2007) 2780–2783
crystals of 2. Yield: 0.25 g (68.9%), elemental analysis: cal-
culated for C42H100Ga4O2P4Si4 (1152.4): C, 43.78; H 8.75.
Found: C, 43.83; H 8.91%.
1
1H NMR (C6D6): d = 2.44 (d, m, PH, JPH = 260 Hz,
2H), 0.9–1.9 (superposition of the isopropyl groups,
98H); 29Si{1H} NMR (C6D6) d = 10.6 (m), 15.2 (m); 31P
1
NMR (C6D6): d = ꢀ244 (m, PH, JP,H = 260 Hz), ꢀ217
(m, P); IR (KBr): 2926 (vs), 2891 (vs), 2867 (vs), 2747
(w), 2710 (w), 2362 (w), 2324 (m), 1459(vs), 1384 (s),
1363 (m), 1286 (w), 1248 (m), 1196 (s), 1151 (w), 1076
(vs), 1043 (vs), 1016 (w), 992 (s), 918 (m), 879 (vs), 807
(w), 732 (w), 673 (vs), 595 (vs), 567 (vs), 508 (vs), 407 (m).
Compound 3: 0.33 g IniPr3 (1.35 mmol) were added to a
solution of 0.21 g [O(SiiPr2PH2)2] (0.67 mmol) in 10 ml tol-
uene. The reaction mixture was stirred for 1 h and subse-
quently cooled to ꢀ35 °C. Colourless crystals of 3 appear
within five days. Yield: 0.28 g (62.2%), elemental analysis:
calc. for C42H100In4O2P4Si4 (1332.8): C, 37.85; H, 7.56.
Found: C, 37.91; H 7.55%.
1H NMR (C6D6): d = 1.95 (d, m, PH, JPH = 254 Hz,
1
Fig. 1. Molecular structure of 2 (ORTEP, thermal ellipsoids set at the
50% probability level). Hydrogen atoms of the organic groups are omitted
for clarity. Selected bond lengths (pm) and angles (°): Ga(1)–P(1)
240.09(8), Ga(1)–P(2) 238.36(11), Ga(1)–P(20) 243.84(8), Ga(2)–P(1)
249.64(8), Ga(2)–P(20) 243.32(8), Si(1)–P(1) 225.89(12), Si(2)–P(2)
225.66(11); P(1)–Ga(1)–P(2) 103.98(3), P(1)–Ga(1)–P(20) 89.01(3), P(2)–
Ga(1)–P(20) 93.37(3), P(1)–Ga(2)–P(20) 86.96(3), Ga(1)–P(1)–Ga(2)
91.49(3), Ga(1)–P(2)–Ga(20) 108.98(3), Ga(1)–P(2)–Ga(10) 86.63(3),
Ga(10)–P(2)–Ga(20) 92.14(3), Si(1)–O(1)–Si(2) 158.20(4).
2H), 0.9–1.9 (superposition of the isopropyl groups,
98H); 31P NMR (C6D6): d = ꢀ268 (m, PH,
1JP,H = 254 Hz), ꢀ251 (m, P); IR (KBr): 2944 (vs), 2844
(vs), 2746 (w), 2709 (m), 2320 (m), 1460 (vs), 1384 (s),
1362 (m), 1286 (w), 1261 (m), 1237 (m), 1180 (s), 1141
(s), 1080 (vs), 1044 (vs), 987 (s), 967 (s), 919 (s), 880 (vs),
806 (m), 663 (s), 598 (vs), 566 (vs), 513 (s), 461 (s), 421 (m).
Compound 4: 1.05 ml 1.6 M n-butyllithium solution
(1.68 mmol) were added to
a
solution of 0.26 g
[O(SiiPr2PH2)2] (0.84 mmol) in 10 ml heptane at 0 °C. The
reaction mixture was stirred for 30 min and than heated up
to 22 °C. Subsequently, 1 ml of TMEDA and then 10 ml
of THF were added. The clear solution obtained was cooled
down to 6 °C. Colourless needle-shaped crystals of 4 appear
within five days. Yield: 0.20 g (47.3% calc. for C22H46Li2-
N2O2P2Si2 (502.6 g/mol)). No satisfying elemental analysis
can be obtained due to partially loss of solvent molecules.
graphic data for the compounds 2–4 can be found in Table
1 and Ref. [5]
Compound 2: 0.25 g GaiPr3 (1.26 mmol) were added to
0.20 g [O(SiiPr2PH2)2] (0.65 mmol). The reaction mixture
was stirred and heated to 70 °C for one hour. During that
time, gas evolution can be observed. Subsequently, the
obtained colourless solid was dissolved in 15 ml of heptane.
Cooling this solution to 6 °C yields colourless rhombic
Fig. 2. Structure of 4 (ORTEP, thermal ellipsoids set at the 50% probability level). Hydrogen atoms are omitted for clarity. Selected bond lengths (pm)
and angles (°): Si(1)–O(1) 165.38(11), Si(1)–P(1) 221.15(12), P(1)–Li(1) 253.1(4), P(1)–Li(2) 248.8(4), Li(1)–N(1) 215.6(6), Li(2)–O(1) 191.2(10); P(1)–Li(1)–
P(10) 116.1(3), P(1)–Li(2)–P(100) 125.6(4), Li(1)–P(1)–Li(2) 142.43(15), Si(1)–O(1)–Si(10) 148.9(2).

C. von Ha¨nisch, S. Stahl / Journal of Organometallic Chemistry 692 (2007) 2780–2783
2783
Table 1
Crystallographic data of 2–4 [5]
Compound
2
3
4
Formula
Space group
C42H100Ga4O2P4Si4
P21/n
2
C42H100In4O2P4Si4
C26H52Li2N2O3P2Si2
Ibca
8
ꢀ
P1
Formula units
Temperature (K)
Lattice constants
2
180
180
200
˚
a (A)
11.385(2)
17.931(4)
14.905(3)
90
103.55(3)
90
11.740(2)
12.674(3)
22.488(5)
103.06(3)
94.02(3)
107.78(3)
3065.5(11)
1.442
17.233(3)
19.417(4)
21.932(4)
90
90
90
˚
b (A)
˚
c (A)
a (°)
b (°)
c (°)
Volume (A )
Density (g/cm3)
3
˚
2958.3(10)
1.294
7339(3)
1.037
2H Range (°)
4–52
17685
5271 (0.0564)
5016
4–48
17188
8702 (0.0845)
7586
4–48
Reflections measured
11119
2824 (0.0395)
2483
Independent reflections (Rint
Ind. reflections with Fo > 4r(Fo)
)
Parameter
257
2.021
0.0478
0.1349
505
1.679
0.0612
0.1564
161
0.209
0.0664
0.2012
ꢀ0.511/0.945
l (Mo Ka) (mmꢀ1
R1
)
wR2 (all data)
Residual electron density (min/max)
ꢀ0.732/0.489
ꢀ1.454/1.174
1
1H NMR (THF-d8): d = ꢀ1.90 (d, JP,H = 150 Hz, PH,
(b) B. Neumuller, E. Iravani, Coord. Chem. Rev. 248 (2004) 817–834;
¨
3
(c) M. Driess, Adv. Inorg. Chem. 50 (2000) 235–284.
[2] (a) M. Westerhausen, S. Weinrich, B. Schmid, S. Schneiderbauer, M.
Suter, H. No¨th, H. Piotrowski, Z. Anorg. Allg. Chem. 629 (2003) 625–
633;
2H), 0.80 (sep., JH,H = 7.5 Hz, CH(CH3)2, 4H), 1.03 (d,
3JH,H = 7.5 Hz, CH(CH3)2, 12H), 1.06 (d, JH,H = 7.5 Hz,
3
CH(CH3)2, 12H), 2.19 (s, N(CH3)2, 12H), 2.34 (s, C2H4
(NMe2)2, 4H); 7Li{1H} NMR (THF-d8): d = 1.46 (s);
(b) C. von Ha¨nisch, B. Rolli, Z. Anorg. Allg. Chem. 628 (2002) 2255–
2258;
(c) N. Wiberg, A. Wo¨rner, D. Fenske, H. No¨th, J. Knizek, K.
Polborn, Angew. Chem. 112 (2000) 1908–1912. Angew. Chem., Int.
Ed. 39 (2000) 1838–1842;
(d) M. Westerhausen, M. Wieneke, W. Schwarz, J. Organomet. Chem.
572 (1999) 249–257;
(e) M. Westerhausen, R. Lo¨w, W. Schwarz, J. Organomet. Chem. 513
(1996) 213–229.
29Si{1H} NMR (THF-d8): d = 25.0 (d, JPH = 57.9 Hz);
1
1
31P NMR (THF-d8): d = ꢀ314 (d, JP,H = 150 Hz); IR
(KBr): 2944 (vs), 2891 (m), 2866 (vs), 2299 (s), 14634 (s),
1385 (m), 1365 (w), 1260 (w), 1214 (w), 1159 (w), 1082
(s), 1051 (vs), 989 (s), 919 (w), 882 (s), 801 (w), 644 (s),
604 (s), 500 (s), 453 (m).
[3] (a) C. von Ha¨nisch, O. Rubner, Eur. J. Inorg. Chem. (2006) 1657–
1661;
Acknowledgement
(b) C. von Ha¨nisch, E. Matern, Z. Anorg. Allg. Chem. 631 (2005)
1655–1659;
We are grateful to the Deutsche Forschungsgemeins-
chaft (DFG) for financial support.
(c) C. von Ha¨nisch, Eur. J. Inorg. Chem. (2003) 2955–2958.
[4] C. von Ha¨nisch, S. Stahl, Angew. Chem. 118 (2006) 2360–2363.
Angew. Chem., Int. Ed. 45 (2006) 2302–2305.
Appendix A. Supplementary data
˚
[5] STOE-IPDS2 (Mo Ka radiation, k = 0.71073 A). The structures were
solved by direct methods and refined by full-matrix least-squares
techniques against F2 (In, Ga, P, Si, O, N, C, Li refined anisotrop-
ically, H atoms at the organic groups were calculated at idealized
positions).
CCDC 615858, 615859 and 615860 contain the supple-
mentary crystallographic data for this paper. These data
can be obtained free of charge via htpp://www.ccdc.cam.
ac.uk/conts/retrieving.html, or from the Cambridge Crys-
tallographic Data Centre, 12 Union Road, Cambridge
CB2 1EZ, UK; fax: +(44) 1223-336-033; or e-mail: depos-
it@ccdc.cam.ac.uk. Supplementary data associated with
this article can be found, in the online version, at
doi:10.1016/j.jorganchem.2006.12.005.
[6] (a) C. von Ha¨nisch, B. Rolli, Phosphorus Sulfur Silicon 179 (2004)
749–757;
(b) C. von Ha¨nisch, Z. Anorg. Allg. Chem. 627 (2001) 68–72;
(c) A. Schaller, H.-D. Hausen, J. Weidlein, Z. Anorg. Allg. Chem. 626
(2000) 616–618;
(d) W. Uhl, M. Benter, Chem. Commun. (1999) 771–772;
(e) J.F. Janik, R.L. Wells, V.G. Young Jr., A.L. Rheingold, I.A.
Guzei, J. Am. Chem. Soc. 120 (1998) 532–537;
(f) K. Niediek, B. Neumuller, Chem. Ber. 127 (1994) 67–71.
¨
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