New diazasilaphosphetidines and their precursors

Article abstract of DOI:10.1515/znb-2000-0502

A series of aminosilanes (R′HN)₂SiR₂ have been prepared. In case of bulky substituents R¹ the aminolysis of Ph₂SiCl₂ stops at the (R′HN)ClSiPh₂ stage. Replacement of the Cl atom is achieved with LiNHR′ which allows the synthesis of mixed bisaminosilanes (R′HN)(R″HN)SiPh₂. The X-ray structures of three of these compounds have been determined. There are no intermolecular N-H...N hydrogen bonds in these compounds in the solid state. Several 1,3,2,4-diazaphosphetidines have been synthesized using bis(N-lithioamino)silanes and bis(N-lithioamino)phosphanes . Amongst these the heterocycle 18 possesses an almost planar four membered N₂SiP ring system.

Full text of DOI:10.1515/znb-2000-0502

New Diazasilaphosphetidines and their Precursors
Bettina Eichhorn and Heinrich Nöth
Department of Chemistry, Inorganic Chemistry, University of Munich,
Butenandtstr. 5 -1 3 (D), D-81 377 München, Germany
Reprint requests to Prof. Dr. Heinrich Nöth. E-mail: H.Noeth@lrz.uni-muenchen.de
Dedicated to Prof. Dr. R. Schmutzler on the occasion of his 65lhbirthday
Z. Naturforsch. 55 b, 352-360 (2000); received January 18, 2000
Bis(monoorganylamino)diorganylsilanes, 1,3,2,4-Diazasilaphosphetinides
A series of aminosilanes (R'HNbSiR: have been prepared. In case of bulky substituents
R' the aminolysis of Ph^SiCb stops at the (R'HN)ClSiPh2 stage. Replacement of the
Cl atom is achieved with LiNHR' which allows the synthesis of mixed bisaminosilanes
(R'HN)(R"HN)SiPh2. The X-ray structures of three of these compounds have been determined.
There are no intermolecular N-H -N hydrogen bonds in these compounds in the solid state.
Several 1,3,2,4-diazaphosphetidines have been synthesized using bis(N-lithioamino)silanes and
bis(N-lithioamino)phosphanes . Amongst these the heterocycle 18 possesses an almost planar
four membered NiSiP ring system.
Introduction
RN=SiR2"
RP=NR
Heterocyclic systems are still an attractive field
of research particularly in relation to the question
of electron delocalisation. From the six formally
related four membered ring systems 1 to 6 only 1
can be considered to be a At: electron system, 1 being
isoelectronic and isostructural with cyclobutadiene
while 2 is reminiscent of a An allylic system. The
diazaphosphaboretidine 3 can be formally viewed as
a 6 Tr electron system provided that the P atom is in a
planar environment. As far as we know [1,2] this is
not the case. Therefore it is electronically akin to 2.
The heterocycles 4 to 6 are best considered as having
localized lone pairs of electrons at the nitrogen and
phosphorus centers. The five membered ring 7 can
be looked at as being a An electron system. However,
the first member of this class of heterocycles clearly
shows no electron delocalization for the NBBN unit
because there is a considerable twist of its BN units
against one another [3].
(3)
R
N -H
R
I
R
R"
I
H -N
'n —Si^ R"
(2)
(1)
-R"
Sic
I
I
R— P
R"
P -N
♦RTCfe
■2HC1
H -N
N -H +R2”SiCl2
^
I
-2HC1
R
.(5)
,
+R2"SiCl2 +RTCI2
-2LiCl - 2 m
U—N
,SiC£..
L i-N
N
^
R
N -L i
/
\
O'*
R— P
N -L i
I
I
R
R
Scheme 1. Routes to 1,3,2,4-diazasilaphosphetidines.
Bis(monoorganylamino)diorganylsilanes
Synthesis and NMR characterization
Several routes to diazasilaphosphetidines can be
envisaged. They are summarized in Scheme 1.
Route (1) requires bis(monoorganylamino)diorgan-
ylsilanes while route (2 ) needs bis(monoorganyl-
amino)phosphanes. For a condensation to 6 hy-
drogen chloride must be removed. This is usu-
ally achieved by triethylamine as an auxiliary base.
Route (3) is a typical cycloaddition reaction be-
tween low coordinated silicon and phosphorus
\
/
/
\
/ s '
N -Si
\
/
\
/ s '
N -Si
N -P
N -B
B -N
11
11
B -N
B -N
JSi—N
\
/
\
/
\
y
\
2
3
! 4
\
/
/
I
\
v s i ' /
w
N -P
I
B-
P -N
P -N
N
/
\
0932-0776/00/0500-0352 $ 06.00 © 2000 Verlag der Zeitschrift für Naturforschung. Tübingen • www.znaturforsch.com
Brought to you by | New York University Bobst Library Technical Services
Authenticated
Download Date | 7/19/15 10:21 PM

353
B. Eichhorn and H. Nöth • New Diazasilaphosphetidines and their Precursors
ph ci
p \ ,c\
X
♦
2 RNH 2
---
~
p./S i
+
RNH3C1
(7)
Ph
c ,
Ph
n hR
Ph. <a
Si
Ph. .NHR'
/Sis
+
RNHLi
----*■
+
LiCI
K ’
Ph^ nhR
^
nhR
species. Routes (4) and (5) may be more effec- effect of the Cl atom. A much larger variation results
tive than routes (1) and (2 ) because of the higher for the 1H resonance of the NH group. Once again,
amongst the series of the alkylamino compounds 12
to 15 this proton is least shielded for the chloride 13.
In compound 15 the two different NH proton signals
could not be separated. Also, the 'H NMR signal
of the NH protons is rather broad for 14 while two
signals could be observed for 12. We were unable
nucleophilicity of the lithium compounds and the
thermodynamic driving force of LiCl formation.
Both routes, (1) and (5) require bis(monoorgan-
ylamino)diorganylsilanes. Compounds 8 to 10 were
prepared according to [1 ] by aminolysis of the re-
spective diorganyldichlorosilane with an excess of a
primary amine. In order to prevent condensation re- to decide whether this indicates the presence of two
actions to cyclosilazanes sufficiently bulky groups different NH groups (which is actually unlikely in
R and R' are required to kinetically stabilize these terms of the l3C resonances) or is due to 3J(1H,1H)
compounds.
with the isopropyl’s CH group.
However, it should be noted that there is a 29Si
shift difference of 25.1 ppm between compounds
8 and 9, in contrast to only 3.7 ppm between 14
and 15.
Me2Si-
Me2Si-
Me2Si-
(NHPhh (10)
-10.8
(NHiPr)2 (8) (nh'Bu)2 (9)
8.9
0.4
-16.2
0.6
<529Si (ppm)
6 1H(N) (ppm)
3.23
Ph2Si-
Ph2Si-
Ph2Si-
(NHPh)2 (11)
-30.2
(NHiPr)2 (12) (Cl)NHiPr (13)
Molecular structures
-27.9
0.97, 0.98
-13.5
1.75
629Si (ppm)
<5'H(N) (ppm)
4.1
The diaminodiphenylsilanes 12, 14 and 15 crys-
tallize well. Single crystals of these compounds
were subjected to X-ray structure analysis in or-
der to study the influence of increasing size of the
amino groups on the molecular structures. These
Ph2Si-
Ph2Si(NHiPr)-
(NH‘Bu)2 (14) NH'Bu (15)
-35.4
1.4
-31.7
1.3 (br)
629Si (ppm)
6'H (N ) (ppm)
Compounds 9 to 11 are already known [4, 5] and
are readily accessible. In contrast the aminolysis
of diphenyldichlorosilane with isopropylamine or
terf-butylamine proceeds readily only as shown
in eq. (7) allowing the synthesis of monoorgany-
lamino(chloro)diphenylsilanes, e. g. 13. Replace-
ment of the Cl atom by an amino group is readily
achieved by using lithium amides. Consequently
the reaction of Ph^SiCL with LiHNR leads directly
to Ph2Si(NHR)2 . On the other hand, aminolysis of
PhiSiCb with an amine followed by reaction with a
lithium amide of a different amine allows the prepa-
ration of “mixed” bis(amino)diphenylsilanes as ex-
emplified for compound 15. Compound 11 was first
described by Anderson [4].
The 1H and l3C NMR spectra of compounds 8 to
15 are unexceptional. And this is true also for 29Si
NMR data, the 29Si nucleus being most deshielded
in compound 13 obviously due to the inductive
Fig 1. Molecular structure of Ph2Si(NHiPr)2 in ORTEP
description. Thermal ellipsoids are depicted on a 25%
probability scale.
Brought to you by | New York University Bobst Library Technical Services
Authenticated
Download Date | 7/19/15 10:21 PM

354
B. Eichhorn and H. Nöth • New Diazasilaphosphetidines and their Precursors
Tab 1. Selected bonding distances (in A) and angles (in °)
of the bis(monoorganylamino)diphenylsilanes.
8
9
10
Sl-N l
S1-N2/N1A
Sil-C l
S1-C7/C1A
1.700(2)
1.709(3)
1.879(2)
1.881(2)
1.710(5)
1.709(5)
1.875(5)
1.875(5)
1.704(4)
1.710(4)
1.877(5)
1.878(5)
Nl-Sil-N2/N1A
C l-Sil-C 7/C l A
114.2(4)
109.2(3)
111.6(9)
1 1 0 .0 2 (8 )
113.1(2)
109.5(2)*
* C9-Sil-C15.
for the two independent molecules of compound 14,
7 1.4° for the bis(isopropylamino) compound 13 and
68.7° for compound 15. This does not reflect a uni-
form trend, although the twist of the phenyl groups
is less for the diphenylsilanes containing isopropy-
lamino groups.
Fig 2. Molecular structure of PhbSHNH'Bu^ in ORTEP
description. Thermal ellipsoids are depicted on a 25%
probability scale.
The sum of bond angles at the nitrogen atoms
is close to 360° for all compounds, and there are
no intermolecular N-H•■•N interactions in the solid
state.
1,3'2,4-Diazasilaphosphetidines
Synthesis and Characterization
Four membered diazasilaphosphetidines are
known for a number of derivatives obtained by
reactions (3) to (5) (see Scheme 1). A new route
is described by eq. (4). The reaction of bis(mo-
noorganylamino)organylphosphanes, after metal-
lation with LiBu, with diorganyldichlorosilanes
yielded compounds 16 to 18. Yields were, how-
ever, unsatisfactory. Therefore, the “reverse” reac-
tion route has been used [11, metallation of di(mono-
organylamino)diorganylsilanes followed by reac-
tion with organyldichlorophosphanes. Application
Fig 3. Molecular structure of Ph2Si(NH'Bu)(NHiPr) in
ORTEP description. Thermal ellipsoids are depicted on a
25% probability scale.
structures are depicted in Figures 1 - 3. The most
important structural parameters are summarized in of this method provided good yields of 18 and 19.
Table 1.
The Si-N bond lengths of the three compounds
can be considered as equal, the mean distance be-
The NMR spectra of the products show a consid-
erable deshielding of the 31P nuclei compared with
the R'P(NHR)2 starting materials. The shift differ-
ing 1.705 A. As expected, the N-Si-N bond angle is ences _\3IP range from 78.6 to 83.7 ppm. This is
largest for compound 15 and smallest for compound most likely due to changes in the N-P-N bond an-
13. The small difference (2.5°) is nevertheless sig- gle on going from the bis(aminoorganyl)phosphane
nificant, and is reflected also in the C-Si-C bond an- to the diazasilaphosphetidine (v. i.). For compounds
gle which is largest for compound 13 and smallest
16 and 17 there are two signals in the 'H and 13C-
for compound 14. No influence of the amino groups NMR spectra for the MeSi groups which indicate
on the Si-C bond lengths is noted. However, the in- that the P atom is not in a planar environment. Both
terplanar angles between the two phenyl groups vary
of them show V ^ 'P 'H ) coupling which is 5.1 Hz
significantly. They are 68.7 and 73.2°, respectively, for 16 and 5.5 Hz for 17.
Brought to you by | New York University Bobst Library Technical Services
Authenticated
Download Date | 7/19/15 10:21 PM

B. Eichhorn and H. Nöth •New Diazasilaphosphetidines and their Precursors
355
N
Me
N
Me
N
^Me
Me— pf Xs (
'Me
N
Ph
Ph— v f XSiX
Ph— p/ NSi'
Ph— / XSi'
16
17
18
19
13.9
130.2
16.6
137.5
-325.8
13.9
125.7
-317
13.5
137.3
-319.5
5MSi
831P
615N
H
N
Me
Me
K >■
N
25% 175
- /-Buten
-56
- /-Buten
-56
H
Fig 4. a) Molecular structure of the diazasilaphospheti-
dine 18. Thermal ellipsoids represent a 25% probability.
H atoms have been omitted for clarity, b) A view along
the P-Si axis to demonstrate ring folding and orientation
of the quartenary C atoms bonded to N atoms. Selected
bond lengths (in A): Pl-N l 1.736(2), P1-N2 1.736(2),
Pl-C l 1.862(2), N1-C7 1.480(3), N2-C11 1.488(3), N l-
Sil 1.735(2), N2-Sil 1.739(2), Sil-C15 1.867(3), Si 1-
C16 1.870(3). - Selected bond angles (in °, all esd’s are
0.1°); N1-P1-N2 84.0, N 1-PI-Cl 104.4, N2-P1-Cl 103.6,
N l-Sil-N 2 83.9, N 1-Si 1-C 15 116.6, N l-Sil-C 16 116.3,
N2-Sil-C15 116.7, N2-Sil-C16 116.1, P l-N l-Sil 95.9,
Pl-N2-Sil 95.9.
V —1+
N
Mel
Me
N
Me I
.7 1
Me
+
N
-
CH3
'Si
k >:
P h -P ' N"
Ph—P^ 'Si
N
I
N' Me
H
53% 119
Scheme 2. Fragmentation pattern for the diazasilaphos-
phetidine 17.
Ring formation leads to a better shielding of the
15N nuclei amounting to shift differences of _\15N =
21 ppm for 16 and 24.9 ppm for 19 compared with
PhP(NHR)2 (R = /Pr, 'Bu) [3]. This may be due to
Mass spectrometric characterization of the di-
the introduction of the more electropositive Si atom azasilaphosphetidines was performed only for com-
as well as to the smaller P-N-Si bond angle in com- pound 17. Scheme 2 shows the most important frag-
parison with the noncyclic counterparts giving the mentations. The molecular ion is fairly abundant
bonds of the N atoms more s-character. This sug- (appr. 5%). However, the most abundant ion is that
gestion is supported by a decrease of the coupling of the phosphenium cation. Thus, breaking the P-
constant 17(3 IP15N) which is 33.1 Hz for 16 and C bond is preferred over breaking the Si-C bonds.
33.4 Hz for 17. The same trends are also observed Obviously a nitrenium based fragment is much less
favored than the phosphenium type ion. This cannot
for the P,Si-phenyl derivatives 18 and 19. In these
cases, the assignment of all 13C NMR signals of the be rationalized only by the weaker P-C bond com-
phenyl groups is not unequivocal in the absence of pared to the N-C bond but particularly by better
special decoupling experiments.
stabilization of the N-P+-N unit.
Brought to you by | New York University Bobst Library Technical Services
Authenticated
Download Date | 7/19/15 10:21 PM

B. Eichhorn and H. Nöth • New Diazasilaphosphetidines and their Precursors
356
!pMe j
\
iiM ej
N
/
\
/
N
/
/
R2N -P ^ ^Si
/
\
/
X _P\
N
N
X_P\ / S'x
I
N
I
SiMei
SiMe3
22
21
20
X = C1, Br
/
\
/ Ph
N - P
Six
\
/
Ph
p\ / Si:
Me
N
25
24
23
Molecular Structure
was best studied e. g. as a reagent for the preparation
of [Me2Si(N'Bu)2Sn] or for spirocyclic titanium
amides [5]. The thermal stability of (RHN^SiRS
compounds clearly increases with the steric demand
of the organyl substituents.
The NMR spectra indicated that the P atoms of
diazasilaphosphetidines do not reside in a planar
environment. This has been ascertained by an X-ray
structure determination on compound 17 as depicted
in Fig. 4.
The four-membered ring is almost planar, as the
folding angle between the planes SiNo and PN2
amounts to only 5°. One of the N atoms exhibits
a planar environment (sum of bond angles 360°),
the other, N2, is slightly pyramidal (sum of bond
angles 354°). It is worth noting that the P-N and
Si-N bond lengths are similar.
The amination of diorganyldichlorosilanes pro-
ceeds stepwise, and many “asymmetrically” substi-
tuted diaminodiorganylsilanes may be prepared by
the route described by eq. (6 ). It would be inter-
esting to see whether Ph2Si(NHtBu)NH2 or even
Me2Si(NHlBu)NH2 are accessible. Both of them
would be versatile reagents. Two compounds akin to
these have been described by P. P. Power et al. [11],
Mes2Si(NH2)2 and Triph2Si(NH2)2 (Mes = mesityl,
Triph = 2,4,6-triphenylphenyl), which demonstrate
that condensation by loss of NH3 can be kinetically
prevented by introducing sufficiently bulky organyl
groups, and indicate that the condensation process
proceeds intermolecularly.
Discussion
Bis(monoorganylamino)silanes were first re-
ported by Anderson [4] including
ber of bis(anilino)diorganylsilanes. However,
bis(methylamino)diorganylsilanes are also acces-
a
num-
According to the literature the standard Si-N sin-
sible [8 ]. These were of interest as intermediates gle bond length is 1.80 A and the standard Si=N dou-
for the formation of 1,3,2,4-diazadisiletidines [9]. ble bond 1.56 Ä [12], Thus the Si-N bond lengths
found for compounds 8 to 10 correspond to single
Amongst these compounds ('BuHN)2SiMe2 [10]
Brought to you by | New York University Bobst Library Technical Services
Authenticated
Download Date | 7/19/15 10:21 PM

B. Eichhorn and H. Nöth ■New Diazasilaphosphetidines and their Precursors
357
bonds and are very similar to data of many other
aminosilanes [13]. The longest Si-N bond, so far,
has been observed for Mes2Si(NH2)2 (1.78(7) A).
This bond length is closest to the calculated single
bond length. The shortening of the Si-N bonds is
currently explained by the bond polarity [13] while
7r-bonding is no longer considered to be essential.
Moreover, it should be noted that the presence of
planar tricoordinated N atoms will also lead to a
shortening of the Si-N single bond length.
In this context it would be of interest to study the
halide abstraction of compound 24 which might lead
to a silenium cation 26, representing a 6tr electron
system provided that the lone pair at the P atom
becomes available for electron delocalization.
Experimental
All manipulation were carried out under anhydrous
conditions using the Schlenk technique and dinitrogen
as a protecting atmosphere. All reagents were used as
supplied. Mass spectra: Atlas CH7 at 70eV ionisation
energy; NMR: Bruker WP200, Jeol GSX 270 and FX
The first 1,3,2,4-diazasilaphosphetidines have
been obtained by Fink [9] by reacting octamethyl-
trisilazane with LiBu followed by R P C b. Obvi- 400 ('H , 13C, 29S i,31P); internal lock: C6D6.
Di(isopwpylamino)dimethylsilane (8): A stirred solu-
tion of isopropylamine (54.8 g, 0.93 mol) in diethyl ether
(250 ml) was cooled in an ice bath, and dichlorodimethyl-
silane (26.6 g, 210 mmol) was slowly added. A white pre-
cipitate formed. After addition stirring of the suspension
was continued for 1 h. Then the insoluble material was
removed by filtration. From the filtrate all volatiles were
removed at 10 Torr, and the remaining liquid subjected to
distillation. Yield: 14 g of 8 (40%), b. p. 35°C/5 Torr.
NMR (CDCh): 61H: -0.02 (s, 6 H, SiMe), 0.4 (s, broad,
2H ,N H ), 1.03 (d,V(HH) = 6.1 Hz, 12HCHM<?),2.9-3.1
(m, 2 H CHMe). - 613C: -0.4 (s, SiMe), 27.9 (s, CHMe),
42.3 (s, CHMe); - <$29Si: 8.9 s. C8H22N2Si (174.36): Calcd
C 55.1, H 12.72, N 16.07. Found C 54.76, H 12.73, N
15.85%.
Di(tert-butylamino)dimethylsilane (9): Prepared as de-
scribed for 8 from ‘BuNH2 (30.0 g, 410 mmol) and
Me2SiCl2 (11.6 g, 90 mmol). Yield: 9.3 g of 9 (51%),
b. p. 65°C/7 Torr, colorless, moisture sensitive liquid.
NMR (CDCh): b1H: 0.005 (s, 6 H, SiMe), 0.6 (s, broad,
2 H, NH), 1.15 (s, 18 H, CMe); - 6I3C: 3.5 (s, SiMe), 33.8
(s, CMe), 49.1 (s, CMe); - <$29Si: -16.2 s. C,oH26N2Si
(202.42): Calcd C 59.34, H 12.95, N 13.84. Found C
57.11,H 13.02, N 13.11%.
Bis(anilino)dimethylsilane (10): Prepared in analogy
to 8 from aniline (34.4 g, 370 mmol) and Me2SiCl2
(11.9 g, 90 mmol) in diethyl ether (200 ml). The filtrate
was reduced in volume to about 80 ml and the solution
layered with pentane. After several hours compound 10
had separated and was isolated. Yield: 18.1 g (81 %), m. p.
113-116 °C.
NMR (CDCI3): <$'H: 0.13 (s, 6 H SiMe), 3.23 (broad,
2 H, NH), 6.7 - 7.1 (m, 10 H, Ph); - <$13C: -1.4 (s, SiMe),
115.0, 117.1, 118.8, 129.5, 146.5 (s, ipso C); - <529Si:
-10.8. Ci4H 18N2Si (242.40): Calcd C 69.37, H 7.48, N
11.56. Found C 68.34, H 7.36, N 11.31 %.
ously, the reaction intermediate is Me2Si(NLiMe)2 ,
which, however, was not characterized at this
time. A route, which provided Si- and P-func-
tional diazasilaphosphetidines was designed by
Niecke et al. [14]. Addition of SiCl4 or SiBr4 to
the iminophosphane (Me3Si)2N=PR followed by
Me^SiHal elimination led to the four membered
rings 2 0 and 2 1 .
Aminolysis reactions performed by Klinge-
biel et al. [15] demonstrated that the P-X bond
of diazasilaphosphetidines is more reactive than
the Si-X bond. The resulting P-aminosubstituted
diazasilaphosphetidines arouse interest because
they formed rotational isomers, and this aspect
has been studied in depth by O.J. Scherer et
al. [1]. Asymmetrically substituted diazasilaphos-
phetidines can also be made by a [2 +2 } cy-
cloaddition between iminosilanes RN=SiR'2 and
iminophophanes RN=PR' [7]. This makes asym-
metrically substituted species available. N-Metal-
lated bis(amino)phosphanes and bis(amino)silanes
now provide alternative routes to the four mem-
bered N2SiP ring system, and it is quite apparent
that these two routes can be considerably extended
in order to prepare new kinds of P- or Si-functional
diazasilaphosphetidines.
Compound 17 is so far the only diazasilaphosphe-
tidine with an almost planar ring configuration
showing a folding angle of only 5.4°. Much stronger
folding is observed for the diazasilaphosphetidines
23 and 24 namely 24 and 22°, respectively [1, 2].
Moreover, both compounds show no truly planar
coordination at their nitrogen atoms. Thus, the sum
of bond angles around the nitrogen atoms of 2 2 is
357 and 355°, and for 23 the values are 350 and 352°
[1,2]. Formation of the cation Me2Si(NlBu)2P+ [16]
leads to a totally planar system.
Di(isopropylamino)diphenylsilane (12): Isopropyl-
amine (76.5 g, 0.9 mol) was dissolved in diethyl ether
(250 ml) and the solution cooled in an ice bath. To
the stirred solution was slowly added PhbSiCh (50.6 g,
Brought to you by | New York University Bobst Library Technical Services
Authenticated
Download Date | 7/19/15 10:21 PM

B. Eichhorn and H. Nöth • New Diazasilaphosphetidines and their Precursors
358
subjected to distillation. 15 distilled at 130 °C/1 Torr.
Yield: 1.28 g (32%). The oil crystallized rapidly, m.p.
133 - 135 °C.
0.2 mol). The precipitate was filtered off after 5 h of stir-
ring. Then ether was removed in vacuo from the filtrate
and the residue distilled. B.p. 110 °C/0.05 Torr, Yield:
40 g of 12 (6 8 %). The liquid solidifies on standing, m. p.
123 - 125 °C.
NMR (C6D6): bxH: 0.97 (s, broad, 1 H, NH), 0.98
(broad, 1H, NH), 1.03 (d, V(H,H) = 6.4 Hz, 12 H, CHMe),
3.3 (m, 2 H, CtfMe), 7.2 - 7.7 (m, 10 H, Ph); - <513C: 27.9
(s, CHMe), 42.6 (s, CHMe), 127.5 (s, p-Ph), 129.1 (s,
m-Ph), 134.7 (s, o-Ph), 138.0 (ipso-Ph); - <$29Si: -27.9.
Ci8H26N2Si (298.51): Calcd C 72.43, H 8.78, N 9.38.
Found C 72.33, H 8.23, N, 9.35%.
NMR (CDCI3): bxH: 1.1 (d, 37(H,H) = 6.4 Hz, 6 H,
CHMe), 1.2 (s, 9 H, CMe), 1.3 (s, broad, 2 H, NH), 3.3
(m, V(H,H) = 6.2 Hz, CHMe), 7.3 - 7.6 (m, 10 H, Ph);
- <513C: 27.7 (s, CHMe), 33.6 (s, CMe), 42.5 (s, CHMe),
49.6 (CMe), 127.5,128.9,134.8,139.0 (//?so-Ph);-<$29Si:
-31.7. C,9H28N2Si (312.53): Calcd C 73.02, H 9.03, N
8.96. Found C 72.96, H 8.33, N 8.94%.
Bis(anilino)diphenylsilane (11): To a solution of di-
phenyldichlorosilane (10.0
g (0.04 mol) in toluene
Chlow-tert-butylamino(diphenyl)silane (13): tert-
Butylamine (13.9 g, 0.19 mmol) was dissolved in a 1:1
mixture of pentane and diethyl ether (200 ml). After
cooling the stirred solution to -20 °C Ph2SiCl2 (12.1 g,
0.08 mol) was added drop wise. The suspension was then
warmed to ambient temperature and kept under reflux for
1 h. Solid material was filtered off and washed with pen-
tane. From the united filtrates all volatiles were removed
in vacuo and the residue distilled. The fraction at b. p.
112 °C/0.03 Torr - yield 10.9 g of 13 (50%) - was a
colorless oily liquid.
NMR (C6D6: 61H: 1.25 (s, 9 H, CMe), 1.75 (broad, 1H,
NH) 7.3 - 7.8 (m, 10 H, Ph); - <5I3C: 33.2, (s, CHMe), 50.8
(CMe), 127.7 (s,p-Ph), 130.3 (s, m-Ph), 134.5 (s, o-Ph),
135.3 (ipso-Phy, - b29Si: -13.5. Ci6H20NClSi (289.88):
Calcd C 66.30, H 6.95, N 4.83. Found C 66.32, H 7.49,
N 4.97%.
(2 0 ml), cooled in an ice bath, was added with stirring
aniline (25 g (0.27 mol). The suspension was then heated
to reflux for 1 h and stirring was continued for 12 h at
ambient temperature. The precipitate was filtered off and
extracted with 60 ml of almost boiling toluene. The vol-
ume of the toluene solution was reduced in vacuo to about
30 ml and then 30 ml of pentane were placed on top of
the solution. Cooling to -30 °C yielded 3.2 g of 11 (26%).
The compound was washed with pentane and dried in
vacuo.
NMR (CDCI3): b]H: 4.1 (s, broad, 2 H, NH), 7.3 - 8.0
(m, 20 H, Ph); - <$13C: 117.2, 118.9, 128.2, 129.2, 130.4,
133.8,134.7,145.7. C24H22N2Si (366.52): Calcd C 78.64,
H 6.05, N 7.64%. Found C 77.92, H 6.09, N 7.33%.
1.3-Di(isopropyl)-2,2-dimethyl-4-phenyl-1,3,2,4-di-
azasilaphosphetidine (16): PhP(NHiPr)2 [3] (0.69 g,
3.07 mmol) dissolved in toluene (10 ml) was metallated
with BuLi at -30 °C (4.02 ml, 6.4 mmol). The solu-
tion was kept under reflux for 1 h and transferred into
a dropping funnel. From there the solution was dropped
into a stirred solution of Me2SiCl2 (0.41 g, 3.2 mmol) in
toluene (10 ml). After warming to ambient temperature
Bis(tert-butylamino)diphenylsilane (14): /^r/-Butyl-
amine (4.24 ml) was dissolved in a mixture of pentane
and THF (70, 20 ml). Then 25.8 ml of n-LiBu (0.04 mol)
was slowly added with stirring. To the yellow solution was
added 13 (10.9 g, 0.04 mol). After heating to reflux for
1 h, 10 ml of water was added and the two phased liquid and stirring over night the solid was removed by filtra-
transferred into a separation funnel. The ether phase was
separated and dried with sodium sulfate. Then ether was
removed and the residue distilled. B. p. 116 °C/0.03 Torr.
Crystals formed in a few days, m. p. 140 - 144 °C. Yield:
8.3 g (25%).
NMR (CDCI3 ): <$'H: 1.2 (s, 18 H, CMe), 1.4 (broad, 2
H, NH), 7.3 - 7.6 (m, 10 H, Ph); - b13C: 33.6 (s, CMe), 49.9
(s, CMe), 127.4 (s, p-Ph), 128.7 (s. m-Ph), 134.9 (s, o-
Ph) 140.1 (//?so-Ph);-<!>29Si: -35.4. C20H3oN2Si (326.56):
Calcd C 73.56, H 9.26, N 8.58. Found C 73.14, H 9.01,
N 8.21 %.
tion, toluene evaporated in vacuo and the residue distilled,
b. p. 80 °C/0.13 Torr. Yield: 0.37 g of 16 (43 %). Yellow
oil. NMR (C6D6): <3‘H: 0.37 (s, 3 H SiMe), 0.44 (s, 3
H, SiMe), 09.1 (d, l/(H,H) 6.4 Hz, 6 H, CHMe), 1.04
(d, V(H,H) 6.3 Hz, 6 H, CHMe), 3.09 (sept. V(H,H) 6.4
Hz, 2 H, CHMe), 7.15 - 8.0 (m, 5 H, Ph); - <$,3C: 4.9
(s, SiMe), b'5N: -325.8 (d, ]J(P,N) = 34.8 Hz); - 29Si:
16.6 (d, 27(P,Si) = 2.6 Hz); - 31P: 137.5 s. C,4H25N2PSi
(280.43): Calcd C 59.96, H 8.99, N 9.99. Found C 58.91,
H 9.23, N 10.02%.
1.3-Di(tert-butyl)-2,2-dimethyl-4-plienyl-l ,3,2,4-di-
azasilaphosphetidine (17): PhP(NH'Bu)2 [3] (12.1 g,
50 mmol) in toluene (50 ml) was metallated as described
for 16 with 63 ml of a 1.56 M LiBu solution in hexane.
The solution was added to Me2SiCl2 (6.81 g, 50 mmol)
in 20 ml of toluene at -78 °C. Work up was carried out as
described for 16. 17 distills at b.p. 8 6 °C/0.13 Torr as an
oil which solidifies, m.p. 71°C. Yield: 7.7 g (52%).
tert-Buty'Iamino-isopropylamino(diphenyl)silane (15):
Isopropylamine (1.17 ml, 14 mmol) dissolved in 20 ml of
pentane and 5 ml of THF was metallated with 8.9 ml of
a pentane solution of LiBu (0.014 mol). To the reaction
mixture was added with stirring 13(3.73 g, 0.013 mol) and
the mixture was kept at reflux for 1h. LiCl was filtered off,
the volatile materials removed in vacuo and the residue
Brought to you by | New York University Bobst Library Technical Services
Authenticated
Download Date | 7/19/15 10:21 PM

359
B. Eichhorn and H. Nöth • New Diazasilaphosphetidines and their Precursors
Tab 2. Crystallographic data and data related to data collection, structure solution and refinement for compounds 12,
13, 15, and 17.
12
14
15
17
Compound
Chem. formula
Form wght.
CisH26N2Si
298.50
Ci9H28N2Si
312.52
Ci6H29N2PSi
308.47
C2oH3oN2Si
316.55
0.19 x 0.3 x 0.32
monoclinic
P2( 1)/c
9.3091(1)
11.4431(1)
18.2046(2)
101.34(1)
1901.41(3)
4
0.08 x 0.3 x 0.7
monoclinic
P2( 1)/n
10.2643(9)
18.2853(14)
10.3445(8)
112.482(1)
1794.0(3)
4
0.1 x 0.1 x 0 .2
orthothombic
P42( 1)c
15.3312(2)
15.3312(2)
17.0722(3)
90
0.1 x 0.15 x 0.15
monoclinic
P2( 1)/n
10.3382(3)
18.2646(6)
10.5648(1)
109.89(1)
1875.87(8)
4
Cryst. size [mm]
Cryst. system
Space group
a [A]
M A]
c [A]
ß
[°J ,
V[A]3
4012.75(10)
8
Z
p (calc.) [Mg/m3]
p [mm-1]
F(000)
1.105
0.128
648
1.081
0.119
1414
1.107
0.125
680
1.078
0 .2 0 2
672
- 1 1 < /z < 1 1 ,
- 1 2 < h < 1 2 ,
-19 < k < 23,
-12 < k < 13
56.18
- \ 2 < h < 1 2 ,
Index range
-19 < h < 19,
-19 < k < 19,
-15 < k < 2 2
58.36
-14 < k
<
14,
-24 < k
<
<
13,
12
- 2 1
<
k
<
22
- 1 2
<
k
57.04
233
58.50
193
2 9 [°]
Temp. [K]
183(5)
193
Refl. collected
Refl. unique
Refl. observed (4a)
R (int.)
No. variables
Weighting scheme3 x/\
GOOF
7616
3320
1907
0.0655
22129
4097
2274
0.1077
10546
3250
2125
0.0984
2 1 2
9101
3878
2309
0.1227
189
2 0 0
223
0.0000/3.7854
1.280
0.0000/3.2910
1.292
0.0705/0.9923
1.084
0.0614/0.8811
1.291
0.0988
0.1365
0.0593
0.1361
0.0523
0.1275
0.0803
0.1194
Final R (4a)
Final wR2
0.277
Larg. res. res. peak [e/A3]
0.261
0 .2 0 1
0.279
a w“ 1 = crFo2 + (xP)2 + yP; P = (F02 + 2Fc2)/3.
NMR (C6D6): <5'H: 0.47 (s, 3 H, SiM e ), 0.52 (s, 3 H,
SiMe), 1.02 (s, 18 H, CMe), 7.3 - 7.8 (m, 5 H, Ph), -
<$13C: 6.2 (2, SiMe), 8.7 (d, 3/(P,C) = 5.5 Hz, SiMe), 32.4
(d, 3/(P,C) = 5.5 Hz, CMe), 50.8 (d, 2/(P,C) = 10.0 Hz,
CMe), 128.0 (s, p-Ph), 129.9 (s, m-Ph), 130.0 (s, o-Ph),
151.8 (d, '/(P C ) = 8.3 Hz, ipso-Ph); - <515N: -317 (d,
’7(P,N) = 34.8 Hz); - <$29Si: 13.9 (d, 2/(P,Si) = 2.6 Hz); -
<53,P: 125.7 s. Ci6H29N2PSi (308.48): Calcd C 62.30, H
9.48, N 9.08. Found C 61.00, H 9.37, N 8.43 %.
3.8 Hz, SiMe), 32.3 (d, V(P,C) = 6.1 Hz, CHMe), 33.0
(d, '/(P,C) = 45.0 Hz, PMe), 50.1 (d, l/(P,C) = 10.7 Hz,
CMe); - <515N: -319.5 (d, '7(P,N) = 34.7 Hz); - <529Si:
13.5 (d, 27(P,Si) = 2.9 Hz); - 31P: 137.3 s. C i,H 27N2PSi
(246.41): Calcd C 53.62, H 11.04, N 11.37. Found C
52.43, H 10.87, N 11.00%.
l,3-Di(tert-butyl)-2,2,4-triphenyl-1,3,2,4-diazasila-
phosphetidine (19): Me2Si(NH'Bu)2 (1.05 g, 3.2 mmol)
in toluene (10 ml) was metallated with LiBu (4.4 ml,
1.56 M) and reacted with PhPCl2 (0.68 g, 3.2 mmol).
Distillation yielded a mixture of 19 with the aminosilane
(approximately 10:1). Therefore, the compound was only
characterized by NMR spectroscopy.
1,3-Di(tert-butyl)-2,2,4-trimethyl-1,3,2,4-diazasila-
phosphetidine (18):
A
solution of Me2Si(NH'Bu)2
(2.91 g, 10 mmol) in toluene (20 ml) was metallated at
-78 °C with LiBu (18.6 ml, 1.56 M solution in hexane).
After heating shortly to reflux this solution was dropped
into a stirred solution of MePCl2 (1.68 g, 10 mmol) dis-
solved in toluene (10 ml). Work up was carried out as
described for 17. B.p. 55 - 57 °C/ 0.1 Torr. Yield: 1.2 g
(34%).
NMR (C6D6): <5*H: 0.28 (s, 3 H, SiMe), 0.34 (s, 3 H,
SPMe), 1.1 (s, 18 H, CMe), 1.24 (d, 2J(Ptf) = 6.1 Hz,
3 H, PMe)\ - bu C: 5.8 (s, SiMe), 9.1 (d, 37(P,C) =
NMR (C6D6): 6 'H: 1.0 (s, CMe), 7-2 - 8.0 (m, Ph); -
bl3C: 32.5 (d, 37(P,C) = 6.0 Hz, CHMe), 51.5 (d, 27(P,C) =
9.2 Hz, CMe), 125 - 140 Ph; - <$29Si: 13.9 (d, l/(P,Si) =
2.6 Hz); - <531P: 130.2 s.
X-ray structure determinations
The selected single crystal was mounted in perfluo-
roether oil on the tip of a glass fiber and put on a gonio-
Brought to you by | New York University Bobst Library Technical Services
Authenticated
Download Date | 7/19/15 10:21 PM

B. Eichhorn and H. Nöth • New Diazasilaphosphetidines and their Precursors
360
meter head which was placed on the support of a Siemens
P4 four circle diffractometer equipped with a low temper-
ature device LT2 and an area detector CCD. MoKo-radia-
tion and a graphite monochromator were used as radiation
source. All measurements were performed at 193 K. The
unit cell dimensions were calculated from at total of 60
frames taken at 4 different setting angles with A c p = 0.3°.
Data collection was performed in the hemisphere mode
collecting data on 1300 frames at two different \-setting
with _\0 = 0.3°. Data reduction was performed with the
program SAINT [17] and the structures solved with direct
methods as implemented in the program SHEXTL [17].
Non hydrogen atoms were refined in anisotropic descrip-
tion including hydrogen atoms in calculated positions
as riding on the respective atom in isotropic descrip-
tion. Relevant data are summarized in Table 2. Further
information (without structure factor tables) are de-
posited at the Cambridge Crystallographic Data Centre
as supplementary publication numbers CCDC 142860
to 142863. Copies of the data can be obtained on
application to CCDC, 12 Union Road, Cambridge
CB2 1EZ, U.K. by quoting the authors and the jour-
nal citation [Fax: intern)+44-1223/336-033; E-mail:
deosit@ccdc.cam.uk].
Acknowledgement
We thank Fonds der Chemischen Industrie and
Chemetall GmbH for support of this work, Mrs. D. Ewald
for recording mass spectra, Mrs. E. Kiesewetter for mea-
suring the IR spectra, Mr. P. Mayer for NMR measure-
ments and Mrs. E. Käser for the elemental analysis.
[1] O. J. Scherer, M. Püttmann, C. Krüger, G. Wol-
mershäuser, Chem. Ber. 115, 2076 - 2124 (1982).
[2] J. Neumann; U. Klingebiel, S. Rudolph, R. Herbst-
Irmer, M. Noltemeyer, J. Organomet. Chem. 151,
43 -49(1986).
[10] M. Veith, Angew. Chem. 87, 287 - 288 (1975);
Angew. Chem. Int. Ed. Engl. 14, 263 - 264 (1975).
[11] K. Ruhlandt-Senge, R. A. Bartlett, M. M. Olmstead,
P. P. Power, Angew. Chem. 105, 459 - 461 (1993);
Angew. Chem. Int. Ed, Engl.
[3] B. Eichhorn, H. Nöth, Eur. J. Inorg. Chem. 1999,
2355 - 2368.
[12] N. Wiberg, G. Reber, G. Müller, J. Chem. Soc.
Chem. Comm. 1980, 591 - 592.
[13] V. Schomaker, D. P. Stevenson, J. Am. Chem. Soc.
63, 37 (1941).
[4] H. H. Anderson, J. Am. Chem. Soc. 73, 5802 - 5803
(1951).
[14] E. Niecke, O. J. Scherer, Nachr. Chem. Techn. 29,
395 - 397. (1975); E. Niecke, W. Bitter, Chem. Ber.
109,415 -425 (1976).
[15] U. Klingebiel, P. Werner, A. Meller, Chem. Ber. 110,
2905-2910(1977).
[5] W. D. Beiersdorf, D. J. Brauer, H. Biirger, Z. Anorg.
Allg. Chem. 475, 56 - 6 6 (1981).
[6 ] J. Neumann, U. Klingebiel, Chem. Ber. 114, 527 -
535 (1981).
[7] A. H. Cowley, R. A. Kemp, Chem. Rev. 85, 367 -
382 (1985); O. Dahl, Tetrahedron Lett. 23, 483 -
1486 (1982).
[16] M. Veith, B. Bertsch, V. Huch, Z. Anorg. Allg.
Chem. 559, 73 - 8 8 (1988).
[8 ] E. Larsson, L. Bjellerup, J. Am. Chem. Soc. 75,993 -
997 (1953).
[9] W. Fink, Helv. Chim. Acta, 45 498 - 508 (1962).
[17] SHELXTL, Siemens Analytical Instruments, Ver-
sion 4.1, SAINT, Siemens Analytical Instruments,
Version 5; SHELXL 93, G. W. Sheldrick, University
of Göttingen (1993).
Brought to you by | New York University Bobst Library Technical Services
Authenticated
Download Date | 7/19/15 10:21 PM