Tri(tert-butyl)plumbyl-phosphanes, synthesis and multinuclear magnetic resonance

Article abstract of DOI:10.1515/znb-2000-1008

The reaction of tri(tert-butyl)plumbyl-lithium (1) with various phosphorus chlorides was studied. With diphenyl-and amino(phenyl)phosphorus chlorides the formation of hexa(tertbutyl)diplumbane (2) and tetraphenyldiphosphane (3) or the respective 1,2-bis(amino)-1,2-diphenyl-diphosphanes [e.g. 5: amino = PhCH₂(^tBu)N] was dominant. The presence of at least one tert-butyl group at the phosphorus atom gave access to tri(tert-butyl)plumbyl-di(tert-butyl)phosphane (4) and to tri(tert-butyl)plumbyl-amino(tert-butyl)phosphanes [amino = ^tBu(H)N (6), Me(Ph)N (7), PhCH₂(Me)N (8), PhCH₂(^tBu)N (9)] via the reaction of 1 with the corresponding phosphorus chlorides. Side products were again 2 and the corresponding diphosphanes, unidentified compounds, and in two cases, bis(phosphanyl)-di(tert-butyl)plumbanes [phosphanyl = ^tBu(H)N(^tBu)P (10), Me(Ph)N(^tBu)P (11)]. Trimethylplumbyl-benzyl(methyl)-amino(tert-butyl)phosphane (12) was prepared for comparison. All compounds were characterized by their ¹H, ¹³C, ¹⁵N (9), ³¹P and ²⁰⁷Pb NMR data. The coupling constants ¹J(²⁰⁷Pb,³¹P) are large and negative, whereas the coupling constants ¹J(²⁰⁷Pb, ¹³C) are small and can be of either sign. The coupling constants ²J(³¹P-N-¹³C) of 6 - 12 indicate a preferred conformation of the substituents at phosphorus and nitrogen.

Full text of DOI:10.1515/znb-2000-1008

Tri(terf-butyl)plumbyl-phosphanes, Synthesis and
Multinuclear Magnetic Resonance
Max Herberhold, Christian Köhler, Volker Tröbs, and Bernd Wrackmeyer
Laboratorium für Anorganische Chemie, Universität Bayreuth, D-95440 Bayreuth, Germany
Reprint requests to Prof. Dr. M. Herberhold or Prof. Dr. B. Wrackmeyer.
E-mail: max.herberhold@uni-bayreuth.de or b.wrack@uni-bayreuth.de
Dedicated to Professor Herbert Schumann on the occasion o f his 65th birthday
Z. Naturforsch. 55 b, 939-945 (2000); received June 19, 2000
Lead, Phosphorus, Triorganoplumbyl Compounds
The reaction of tri(ter/-butyl)plumbyl-lithium (1) with various phosphorus chlorides was
studied. With diphenyl- and amino(phenyl)phosphorus chlorides the formation of hexa(tert-
butyl)diplumbane (2) and tetraphenyldiphosphane (3) or the respective l,2-bis(amino)-l,2-di-
phenyl-diphosphanes [e. g. 5: amino = PhCH2(,Bu)N] was dominant. The presence of at least
one terr-butyl group at the phosphorus atom gave access to tri(ter/-butyl)plumbyl-di(terr-but-
yl)phosphane (4) and to tri(ter/-butyl)plumbyl-amino(teJT-butyl)phosphanes [amino = fBu(H)N
(6), Me(Ph)N (7), PhCH2(Me)N (8), PhCH2('Bu)N (9)] via the reaction of 1 with the corre-
sponding phosphorus chlorides. Side products were again 2 and the corresponding diphos-
phanes, unidentified compounds, and in two cases, bis(phosphanyl)-di(ter/-butyl)plumbanes
[phosphanyl = 'Bu(H)N('Bu)P (10), Me(Ph)N('Bu)P (11)]. Trimethylplumbyl-benzyl(methyl)-
amino(rm-butyl)phosphane (12) was prepared for comparison. All compounds were charac-
terized by their'H , i3C, l5N (9 ),31P and2 Pb NMR data. The coupling constants './(207Pb,31P)
are large and negative, whereas the coupling constants './(207Pb, C) are small and can be of
either sign. The coupling constants 2/( 3 P-N-13C) of 6 - 12 indicate a preferred conformation
of the substituents at phosphorus and nitrogen.
Introduction
Results and Discussion
Syntheses
Lead-phosphorus compounds are of interest be-
cause of their labile Pb-P bond which may read-
ily be cleaved either homo- or heterolytically, de-
pending on the reaction conditions. However, only
Trialkylplumbyl-diorganophosphanes
The reaction of tri(terr-butyl)plumbyl-lithium
very few plumbyl-phosphanes, R^Pb-PRi, (e. g., R = (1 ) with diphenylphosphorus chloride did not
lead to the desired lead-phosphorus compound
but gave hexa(te/7-butyl)diplumbane (2 ) and
tetraphenyldiphosphane (3) instead (Scheme 1(a)).
Me, Ph; R1 = Ph) are known. They have been pre-
pared either by the reaction of triphenyllead chloride
with diphenylphosphane in the presence of triethyl-
amine [1 ], by treatment of triorganolead chlorides
with lithium phosphides [2 ], or by the reaction of
trimethylplumbyl-diethylamine with diphenylphos-
phane [3, 4], We now report on the reaction of
trialkylplumbyl-lithium with phosphorus halides,
focusing mainly on tri(te7t-butyl)plumbyl-lithium
(1) [5], as a new route to plumbyl-phosphanes.
Attempts were also made to prepare hitherto un-
known trialkylplumbyl-amino(organo)phosphanes.
This work continues a systematic study of tri(tert-
butyl)plumbyl-element compounds with respect to
their synthesis and NMR spectroscopic properties
[5 - 7].
A
similar result was obtained when tri(tert-
butyl)plumbyl iodide was reacted with lithium
diphenylphosphide (Scheme 1(b)). In the case of
the latter reaction, rm-butyl(diphenyl)phosphane
was detected as a further product. Therefore, it
appears that the diplumbane and the diphosphane
are more stable than the corresponding plumbyl-
phosphane. However, in the presence of bulky tert-
butyl groups at the phosphorus atom, tri(terf-butyl)-
plumbyl-di(r^rr-butyl)phosphane (4) was obtained
(Scheme 1(c)), whereas 2 and tetra(ter?-butyl)di-
phosphane were only formed as minor products
(5 - 20%).
K
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940
M. Herberhold et al. •Tri(fer/-butyl)plumbyl-phosphanes
R
Ph2P — PPh2
(b)
3
R1— N
+ Ph2PLi
\
R\
>Bu3Pbl
P - 'Bu
N - R
'Bu
'Bu3Pb— Pb'Bu3
' LiCI
/
P
+
'Bu2Pt(^
'Bu3Pb—
P - 'Bu
(a)
11
7
10
6
/
(c)
<Bu2PCI
+ Ph2PCI
- LiCl
R1—N
R =
H
Me
Ph
Me
Ph
R =
H
\
R1= 'Bu
R
R1= 'Bu
>Bu3PbLi
>Bu3P b - P(Bu2
- LiCl
4
1
R1
N -R
/
C I - Px
(a)
Scheme 1.
R1
I
N -R
+
-LiCl
In order to compare NMR data, we tried to
prepare trimethylplumbyl-di(rm-butyl)phosphane,
Me3Pb-PBu2. These experiments were not suc-
cessful, neither by reacting IVte^PbLi [8 ] with Cl-
P'Bu2 nor by treating Me^PbBr with 'Bu2PH/NEt3
or LiP'Bu2.
'Bu
/
Cl—P.
N - R
(b)
'Bu3PbLi
'Bu
'Bu3Pb— P
\
’Bu
1
LiCl
8
9
= CH2Ph CH2Ph
= Me 'Bu
Trialkylplum byl-am ino(organo)phosphanes
Scheme 3.
As shown for diphenylphosphorus chloride
(Scheme 1(a)), the reaction of amino(phenyl)-
phosphorus chlorides with tri(ter/-butyl)plumbyl-
lithium (1 ) did not afford the desired plumbyl-
phosphanes. Instead, formation of the diplumbane
2 and of l,2 -bis(amino)diphenyldiphosphanes was
observed, even in the presence of fairly bulky
substituents at the nitrogen atom (Scheme 2). In
most cases, mixtures containing numerous phos-
phorus compounds were formed (as monitored by
31P NMR). However, the reaction according to
Scheme 2 gave 2 and the diphosphane 5 with-
out an appreciable amount of other products. The
]H, 13C and 31P NMR spectra indicate that the
formation of the diphosphane 5 takes place in a
diastereoselective way. Comparable diphosphanes,
but in each case as the expected 1 : 1 mixture of
diastereomers, have been prepared by reduction of
the amino(organo)phosphorus chlorides with alkali
metals [9].
Me Ph
N—/
/
Me
c i-p\
'Bu
/
Me3PbLi
Me3Pb — PN
- LiCl
'Bu
1 2
Scheme 4.
By using amino(terr-butyl)phosphorus chlorides,
the corresponding plumbyl-phosphanes 6 - 9 were
obtained which are sufficiently stable in order to al-
low for their NMR spectroscopic characterisation.
In the presence of less bulky substituents at the ni-
trogen atom, e. g. terr-butyl together with H, Me
and Ph, or Me and CH2Ph, other reactions domi-
nate. Thus, 6 and 7 are formed together with the
bis(phosphanyl)plumbane 10 and 11, respectively,
and also together with considerable amounts of
2 and the l,2 -bis(amino)-l,2 -di(rm-butyl)diphos-
phanes. Some of these results are summarized in
Scheme 3.
Ph
N—
\
/
P — P
*Bu
Ph
\
Ph
/
\
The trimethylplumbyl derivative 12, the analogue
of 8 , was prepared from Me3 PbLi and the corre-
sponding phosphorus halide (Scheme 4). A small
amount of tetramethyllead was found as a side prod-
uct. Obviously, this reaction proceeds more cleanly
than in the case of fBu3PbLi, and formation of the
diphosphane was not observed. Thus, it is primar-
1/2
N\
'Bu
Ph
/
C l- P
5
Ph
*Bu3PbLi
—
-LiCl
1
1/2
*Bu3Pb— Pb'Bu3
Scheme 2.
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M. Herberhold et al. ■Tri(terf-butyl)plumbyl-phosphanes
941
Table 1 .13C ,31P and 2()7Pb NMR data[a,b| of tri(terf-butyl)plumbyl-phosphanes 4, 6 - 9, bis(phosphanyl)di(ter/-butyl)-
plumbane 11, and of a trimethylplumbyl-phosphane 12 for comparison.
<§207Pb
Comp.
<531P
<S13C
<S,3C
<SI3C
Pb[C(CH3)3]3
N(R)R'
[ /( Pb, P)]
PC(CH3)3
—
4
6
7
56.3 [+42.5] (< 1),
34.9 [+15.3] (1.5)
47.5 (2.0), 30.5 (17.4) 54.3 [+13.1],
34.5 [+12.6]
165.6 [-1951] 117.8
112.4
34.8 M 3.8),
35.4 (+13.6)
47.0 [--1796]
53.5 (15.3), 33.1 (5.9) rBu
-2029]
99.6 [-
130.2 39.5 (+43.4) Me, 151.6 (< 2) Ph, 116.6 48.9 (-11.4),
(6.5) ortho, 128.7 meta, 118.1 (1.9) para 32.1 (+17.1)
156.2 n.a.
54.1 [+62.7] (1.5),
34.3 [+15.3] (1.1)
n.a.
8
89.5 [--1983]
[-1971]
n.a.
47.8(11.8),
C>[c]
55.3 [-14.2],
34.7 [+17.4]
57.1, 34.7[f]
48.0 (11.0), 31.9 (17.0),
145.6
168.1 58.7 (20.9), 29.5 (13.2) lBu,
69.6 [11.4] (6.0), 144.7 ( < 1) CH^Ph[d] 31.5(17.5)
Ute]
140.4,
145.5 [-2070],
122.0 [-2061] 139.8
[-1736] 124.8 45.0 (2.0) Me,
40.4 (44.2), 40.4 (44.2) Me, n.a. Ph
47.5 (11.0), 32.3 (17.0)
39.3 [35.0] (2.0),
30.0 [44.3] (17.2)
12
-0.3 Me3Pb
[+24.1] (3.5)
-99.3
65.6 [27.1], 140.1 (6.4) CH2Ph[g]
[al Measured in C6Ö6 at 25 ± 1 °C; coupling constants 7(207Pb, l3C) (± 1 Hz) and ’/( “^ P b , 31P) (± 2 Hz) are given
in square brackets, and /( 31P, l3C) (± 1 Hz) in parentheses; n.a. means not assigned due to overlap with signals of
other compounds in the mixture; for 31P NMR data of 10 see Fig. 1. [b| If the sign of a coupling constant is given, it
was experimentally determined at least for one example, and in the case of '7(2 P b ,31P), all signs are alike because
of the similar magnitude of all these coupling constants. [cl <$15N -326.5; 'i( 3lP, l5N) = 81.4 Hz. [dl Other (5I3C data:
128.3 ortho, 128.6 meta, 126.7 para. [el Mixture (1:1) of diastereomers. [f] l3C resonances are broadened; satellites
corresponding to 7(207Pb, l3C) cannot be assigned with certainty. tgl Other <5I3C data: 128.3 (1.3) ortho, 128.6 meta,
127.4 para.
phosphane and not the presence of three tert-butyl
groups at the lead atom as in 8 .
NMR spectroscopic results
13C, 31P and 207Pb NMR data are given in Table 1,
*HNMR data are listed in the experimental section.
Although it was not possible to isolate the plumb-
yl-phosphanes as pure compounds, their molecular
structure in solution follows unambiguously from
the consistent set of NMR data. The progress of the
reactions was monitored by31P NMR, the formation
of Pb-P bonds being indicated by the appearance of
207Pb satellites (Fig. 1). Complementary informa-
tion was obtained from the signal for1Bu3Pb-PbrBu3
(2) (<5207Pb = 335.1 [5]) and the splitting of other
207Pb NMR signals into the expected doublets due
1796 Hz; satel- to '/(^ P b , 3 1 P) or, e.g. in the case of 7 and 10,
Fig. 1. Part of the 101.3 M H z31P{1H} NMR spectrum of
the reaction mixture containing Bu3Pb-P('Bu)N(H)rBu
(6) [<S3,P 112.4, ’7(207Pb,31P)
=
lites are marked by asterisks], the mixture of dia-
stereomers 'Bu2Pb[P('Bu)N(H)'Bu]2 ( 10) [<531P 118.5,
i7(207pb,3ip) = !828 Hz, and 106.9, 'y(5o7Pb,3lP) =
1751 Hz; satellites are marked by arrows], and 1,2-
bis(terr-butylamino)-l,2-di(terf-butyl)diphosphane (<$31P
31.1; the signal is outside of the range shown here).
into doublets and triplets, since the bis(phosphan-
yl)plumbane 10 is present as a 1 : 1 mixture of two
diastereomers. The assignment of the 'H and I3C
NMR signals was straightforward in most cases,
except for 8 because of the numerous side products
which could not be identified.
ily the bulkiness of the amino group which helps
to stabilize the respective plumbyl-amino(organo)-
The <5207Pb values of 4 and of 6 - 9 cover a range
of about 120 ppm. Even the change of substituents
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M. Herberhold et al. •Tri(tert-butyl)plumbyl-phosphanes
942
Table 2. Comparison of <53IP values for plumbyl-phos-
phanes and corresponding phosphorus chlorides.
7
9
12
6
8
112.4
136.8
-22.4
130.2
159.2
-29.0
156.2
163.3
-7.1
168.1
161.0
+7.1
124.8
163.3
-38.5
6 31 P
<531P(P-C1)
^ 3 1 p [a]
-50
-25
[al zA31P = <$3IP - <§3IP(P-C1)
-0
/H
at the nitrogen atom, three bonds away from the lead
atom, gives rise to a range of 6 207Pb data of about
100 ppm. This indicates that steric effects exerted by
the bulky substituents at the phosphorus atom cause
changes in the bond angles at the lead atom. It ap-
pears that smaller substituents at the nitrogen atom
induce less 297Pb nuclear deshielding [e.g., com-
pare <5207Pb for 6 (47.0) with <$207Pb for 9 (145.6)].
This is not necessarily reflected by the coupling con-
stants '7(207Pb,3 1 P) since they are already large and
negative, as expected for the influence of the lone
pair of electrons at the phosphorus atom [1 0 ] and
the readily polarisable Pb-P bonds [4]. This argu-
ment is supported by the small difference between
the magnitude of 1J(207Pb,3 1 P) of 8 (-1983 Hz) and
the corresponding trimethylplumbyl derivative 12
(-1736 Hz), although the trend is in line with other
examples of tri(terf-butyl)plumbyl and trimethyl-
plumby1-element compounds [5-7].
-
25
50
[HZ]
Fig. 2. Contour plot of the 62.9 MHz 2D 13C/' H HETCOR
experiment for 'Bu3Pb-P'Bu2 (4), based on 2/ ( 13C,'H) =
6.5 Hz, showing the range of the Pb-13C(^Bu) resonance.
The positive tilt of the cross peaks for the :07Pb satellites
indicates that 17(207Pb,13C) and 3/( 207Pb,'H) (> 0) have
alike signs.
In principle, the effects which influence the
<5207Pb values should also affect the 31P chemi-
cal shifts. By comparison (Table 2) of the <531P
data for the plumbyl-phosphanes with those of the
corresponding phosphorus chlorides [<53 1 P(P-C1)], a
marked shielding effect upon substituting the Cl-P
by the Pb-P bond becomes apparent only for the less
bulky P-amino groups or if the Me^Pb group (12) is
present instead of the 'Bu^Pb group.
The coupling constant 1Jr(207Pb,13C) of 'Bu^Pb
groups can become small, depending on the nature
of the fourth substituent. So far, the only substituent
which induces a change of the sign from positive to
negative was the 'Bu^Pb group itself in 2 [5]. Here,
we have determined a positive sign for this coupling
constant in 4 (Fig. 2), 6 and 7. However in 9, where
steric repulsion is at a maximum in this series, the
sign of 'y(207Pb, l3C) changes to negative (Fig 3).
Clearly, the simple model of rehybridisation [11]
cannot be applied here in order to explain the trends
of the 1y(207Pb, l3C) values. It should be noted that
the information on the coupling sign is crucial, since
Fig. 3. Contour plot of the 62.9 MHz 2D "C / H HETCOR
experiment for ,Bu3Pb-P(,Bu)N(?Bu)CH2Ph (9), based
on 2/ ( l3C, 'H) = 6.5 Hz, showing the range of the Pb-
C(^Bu) resonance. The negative tilt of the cross peaks
for the 2()7Pb satellites indicates that '/( 207Pb,l3C) and
3y(207Pb,’H) (> 0) have opposite signs.
the values './(207Pb, 13C) of 6 and 9 are numerically
almost identical but their sign is different. The posi-
tive sign of 1J(207Pb, 13C) of the Me^Pb group in 12
is in agreement with the linear correlation between
27(207Pb, 1 HMe) and ‘/(^ P b , 13CMe) [1 2 ],
Both sign and magnitude of the geminal coupling
constants 27( 31 P-N-13C) in aminophosphanes reveal
the preferred conformation of the amino group with
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M. Herberhold et al. • Tri(?gr?-butyl)plumbyl-phosphanes
943
Table 3. Comparison of coupling constants 2/(;3IP-N-13C) of plumbyl-phosphanes and 27(3iPp_ci-N-13C) of the
corresponding phosphorus chlorides[a].
6
7
1 1
9
1 2
27(31P-N-i3C)
27(3,Pp_ci-N-13C) +10.4 ('BuN) < 1 (MeN)
18.5 (PhN) 18.5 (PhN) -7.0 (-CH?N)
15.3 ('BuN)
43.4 (MeN) 44.2 (MeN) 20.9 (‘BuN), 6.0 (-CH.N)
2.0 (MeN), 27.1 (-CH2N)
< 1 (MeN)
+32.8 (-CH.N)
< 1 (MeN)
+20.2 ('BuN)
[a) The signs of the coupling constants 2J(31P-N-13C) of the phosphorus chlorides were experimentally determined [14].
R1
Me3PbLi [8] and the phosphorus halides, 'BU2PCI [16],
R
amino(phenyl)- and amino(terf-butyl)phosphorus chlo-
rides [14] were prepared as described or obtained and
used as commercial products [Ph2PCl, Ph2PH, BuLi
(1.6 M in hexane)]. NMR spectra were recorded with
Bruker ARX 250, AC 300 and DRX 500 spectrome-
ters equipped with multinuclear units. The DRX 500,
with three independent frequency channels, served for
heteronuclear i3C {'H ,31P} triple resonance experiments
in order to assign relevant l3C NMR signals in mix-
tures. Chemical shifts are given with respect to Me4Si
[<5'H = 7.15 (C6D5H); 7.24 (CHCI3/CDCI3), <S13C =
128.0 (CöDö); 77.0 (C D C I3 )], external neat M eN02
[<5I5N = 0 for E ( I5N) = 10.136767 MHz], external H3PO4
(85%, aq.) [<$3,P = 0 for E (31P) = 40.480747 MHz],
and external neat Me4Pb [<$2(l7Pb = 0 for H (207Pb) =
20.920597 MHz],
0
I
o
I
N
N
*P -----
'Bu''
V
\
’Bu"'"" V
\
R1
V
R
V
Pb’Bu3
Pb'Bu3
R in syn position
R in anti position
Scheme 5.
respect to an axis representing the assumed orienta-
tion of the lone pair of electrons at the phosphorus
atom (Scheme 5). Thus, a ^«-orientation of the N-C
bond with respect to the lone pair of electrons is re-
flected by a large and positive coupling constant
2/( 3 1 P-N-13C), whereas this coupling constant is
small and of either sign for the a«r/-orientation [13].
The amino(r<?rf-butyl)phosphorus chlorides used
in this work prefer a certain conformation as a re-
Reaction o f tri(tert-butyl)plumbyl-lithium (1) with di-
sult of steric crowding, indicated by the relative phenylphosphorus chloride
magnitude of the geminal coupling constants. Ta-
Tri(rm-butyl)plumbyl-lithium (1 mmol) was prepared
ble 3 shows the comparison of 27(3 1 P-N-13C) for
6 , 7, 9, 11, and 12 with those of the correspond-
ing phosphorus chlorides ( 2/ ( 31 PP_CrN -13C)). With
the exception of 7 and 11, the preferred conforma-
tion of the plumbyl-phosphanes can be assumed
to be similar to that of the phosphorus chlorides.
In the case of benzyl(terr-butyl)amino(terr-butyl)-
phosphorus chloride the molecular structure in the
solid state [14] confirms the favoured conformation
in which the tert-butyl groups at nitrogen and phos-
phorus avoid any contact and the N-'Bu group is
approximately in ^«-position.
from tri(terr-butyl)plumbyl iodide (0.505 g; 1 mmol)
in THF [5], and diphenylphosphorus chloride (0.22 g,
1 mmol) was added in one portion at -50 °C. After warm-
ing to r. t., the 31P NMR spectra of the reaction mix-
ture indicated the presence of tetraphenyldiphosphane (3)
and of terf-butyl-diphenylphosphane, and the 207Pb NMR
spectrum showed one signal at <5207Pb = 335.1 for hexa-
(terr-butyl)diplumbane (2). After removing all volatile
material the residue was dissolved in 5 ml of hexane and
filtered. Then hexane was removed in vacuo and CöDö
was added in order to record l3C NMR spectra.
3: l3C{'H} NMR (75.5 MHz, C6D6): 6 (/(3IP,I3C)) =
136.5 (10.6) (pseudo-t, C-ipso)', 134.8 (26.0) (pseudo-
t, C-ortho)\ 128.4 (22.0) (pseudo-t, C-meta)\ 128.4 (C-
para). - 31P{1H} NMR (121.5 MHz, C6D6): b =-13.7.
Experimental
All reactions were carried out in an inert atmosphere
of Ar or N2, using carefully dried solvents and oven-
dried glassware, and generally observing all necessary
precautions to exclude moisture and oxygen. Starting
materials such as the hexa(ter/-butyl)diplumbane (2)
and rBu3PbI [15] for the synthesis of 'Bu^PbLi [5],
terr-Butyl-diphenylphosphane: 13C{1H} NMR (75.5
MHz, C6D6): 6 (7(31P, l3C)) = 137.9 (20.0) (d, C-ipso);
135.0 (19.7) (d, C-ortho)\ 128.7(16.5) (d, C-meta); 128.4
(C-para)-, 30.8 (15.7) (d, CP); 28.9 (14.8) (d, CH3-CP). -
3IP { 'H } NMR (121.5 MHz, C6D6): 6 = 17.1.
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944
M. Herberhold et al. ■Tri(terf-butyl)plumbyl-phosphanes
Reaction o f tri(tert-butyl)plumbyl iodide with lithium di-
phenylphosphide
1.2-Bis(rm-butylamino)-1,2-di(terf-butyl)diphos-
phane: 'H NMR (250.13 MHz, C6D6): 6 (7(31P, 'H)) =
1.108(11.7) (pseudo-t, 18H,'BuP); 1.47 (s, 18H 'BuN);
A suspension of lithium diphenylphosphide (0.19 g,
1 mmol) was freshly prepared from diphenylphosphane
and n-butyl-lithium (1.6 M in hexane), and tri(rm-but-
yl)plumbyl iodide (0.505 g; 1 mmol) was added in one
portion at -50 °C. After warming to r. t. and stirring for 3 h,
the 31P- and 207Pb NMR spectra of the reaction mixture
showed that tetraphenyldiphosphane (3) and hexa(tert-
butyl)diplumbane (2) were present.
-
I3C{'H} NMR (62.9 MHz, C6D6): 6 (7(31P,I3C)) =
51.0 (15.1) (pseudo-t, CN); 32.7 (s, CH3-CN); 31.6 (s,
CP); 22.3(24.5) (pseudo-t, CH3-CP). - 31P{‘H} NMR
(101.25 MHz, C6D6)<5 = 31.1.
Tri(tert-butyl)plumbyl-methyl(phenyl)amino(tert-butyl>-
phosphane (7)
The reaction was carried out in the same way as de-
scribed for diphenylphosphorus chloride (vide supra),
and led to a mixture of compounds containing 7, 11,
2 and l,2-bis[methyl(phenyl)amino]-l,2-di(terf-butyl)di-
phosphane.
7: 'H NMR (300.13 MHz, C6D6): «5 [/(207Pb, 1H)]
(7(31P, 'H)) = 3.21 [6.9] (< 1) (s, 3H, MeN); 1.62 [99.2]
(< 1) (s, 27H, 'Bu3Pb); 1.27 [< 2] (13.5) (d, 9H, 'BuP);
not assigned: PhN.
Tri(tert-butyl)plumbvl-di(tert-butyl)phosphane (4)
The reaction was carried out in the same way as de-
scribed for diphenylphosphorus chloride (vide supra).
2()7Pb and 31P NMR spectra showed the presence of 2
and 3 as minor products (ca. 20%) in addition to tri(tert-
butyl)plumbyl-di(terf-butyl)phosphane (4) (see Table 1
for l3C ,31P and 207Pb NMR data).
4: 'H NMR (300.13 MHz, C6D6): 6 [/(207Pb, 1H)]
(/(3IP, ’H>) = 1.74 [96.3] (s, 27H,fBu3Pb); 1.45(10.9) (d,
18H,'Bu2P).
1.2-Bis[methyl(phenyl)amino]-1,2-di(terf-butyl)di-
phosphane: 'H NMR (300.13 MHz, C6D6): 6 (7(31P,
'H)) = 3.27 (s, broad, MeN); 1.07 (13.5) (pseudo-t, 'BuP);
not assigned PhN. - 13C {‘H} NMR (75.5 MHz, C6D6):
6 (7(31P, 13C)) = 39.9 (8.0) (pseudo-t, MeN); 36.4 (17.1)
(pseudo-t, CP); 29.1(19.6) (pseudo-t, CH3-CP), not as-
signed PhN. - 31P{'H} NMR (121.5 MHz, C6D6): 6 =
57.0.
Tetra(terr-butyl)diphosphane: 'H NMR (300.13 MHz,
C6D6): 6 (7(31P, 'H ))= 1.40 (12.3) (pseudo-t).-31P{'H}
NMR (121.5 MHz, C6D6): 6 = 41.0.
Reaction o f tri(tert-butyljplumbyl-lithium (\) with
benzyl(tert-butyl)amino-(phenyl)phosphorus chloride
Tri(tert-butyl)plumbyl-benzyl(methyl)amino(tert-butyl)-
phosphane (8)
The reaction was carried out in the same way as de-
scribed for diphenylphosphorus chloride (vide supra), and
according to 207Pb and 31P NMR spectra of the reaction
mixture the diplumbane (2) together with l,2-bis[benzyl-
(terf-butyl)amino]-l,2-diphenyldiphosphane (5) were the
sole products.
The reaction was carried out in the same way as de-
scribed for diphenylphosphorus chloride (vide supra), and
led to a mixture of compounds containing 8 (see Table 1
fo r31P and 207Pb NMR data) and a large number of other
phosphorus containing compounds which were not iden-
tified.
5: 'H NMR (300.13 MHz, C6D6): 6 (7(31P, ’H)) =
1.02 (s, 18H, 'BuN); 3.65 (s, 4H, CH2) 7.1 (m, 2H, H-
para), 7.18 (m, 4H, H-meta); 7.34 (m, 4H, H-ortho). -
13C{'H} NMR: 6 (7(31P,13C)) = 56.3 (21.0) (pseudo-d,
CN); 29.4 (s, CH3-CN); 47.4 (s, CH2N); Ph-C not as-
signed. - 31P{'H} NMR (121.5 MHz, C6D6): 6 = 16.4.
Tri(tert-butyl)plumbyl-benzyl(tert-butyl)amino(tert-but-
yl)phosphane (9)
The reaction was carried out in the same way as de-
scribed for diphenylphosphorus chloride (vide supra),
Tri(tert-butyl)plumbyl-tert-butylamino(tert-butyl)-
phosphane (6)
and led to
a mixture of compounds containing 9,
2
and l,2-bis[benzyl(/m-butyl)amino]-l,2-di(terf-but-
The reaction was carried out in the same way as de-
scribed for diphenylphosphorus chloride (vide supra), and
led to a mixture of compounds containing 6, 10 (see Fig-
ure 1), 2 and l,2-bis(terr-butylamino)-l,2-di(terf-butyl)-
diphosphane.
6: 'H NMR (300.13 MHz, C6D6): 6 [7(207Pb, 1H)]
(/(3IP, 'H)) = 1.69 [89.4] (s, 27H, 'Bu3Pb); 1.22 (13.0)
(d, 9H, 'BuP); 1,76(s, 9H, 'BuN).
yl)diphosphane (<53IP = 53.0), in addition to a small
amount of other unidentified phosphorus compounds
(<53,P = 83.0,144.0, 180.3).
9: 'H NMR (300 MHz, C6D6): 6 [7(207Pb, 1H)] (7(3,P,
1H)) = 1.37 (13.3) (d, 9H, 'BuP); 1.34 (s, 9H, 'BuN); 5.28
(d, 2/(H,H) = 16.6 Hz, 1H, HCN), 4.29 (d, 27(H,H) =
16.6 Hz, 1H, HCN); 1.74 [89.0] (s, 27 H, rBu3Pb); 7.5 -
7.0 (m, PhN).
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M. Herberhold et al. • Tri(ter?-butyl)plumbyl-phosphanes
945
was filtered off, and all volatile material was removed in
vacuo to leave 0.29 g (64%) of 12 as a yellow oil.
Trimethylplumbyl-benzyl(methyl))amino(tert-butyl)-
phosphane (12)
12: 1H NMR (300 MHz, C6D6): 6 [/(207Pb, !H)] (7(31P,
1H)) = 0.94 [-39.9] (1.3) (d, 9H, Me3Pb); 1.23 [7.0] (13.5)
(d, 9H, 'BuP); 2.57 [7.8] (5.1) (d, 3H, MeN); 4.16 [11.5]
(< 1) (d, l/(H ,H ) = 16.7 Hz, 1H, CH-N), 4.13 [11.6] (< 1)
(d, 27(H,H) = 16.7 Hz, 1H, CH-N) 7.15- 7.24 (m, 5 H, Ph).
Benzyl(methyl)amino(terr-butyl)phosphorus chloride
(0.23 g; 1 mmol) was added in one portion at -50 °C to
a freshly prepared solution of trimethylplumbyl-lithium
(1 mmol) [8] in THF (20 ml). The mixture was warmed
to r. t. and kept stirring for 3 h. The 207Pb NMR spectrum
of the reaction mixture showed the presence of a small
amount of tetramethyllead in addition to 12, whereas the
31P NMR spectrum showed that 12 was the dominating
species containing phosphorus. After removing the THF
in vacuo, 10 ml of hexane were added, insoluble material
Acknowledgements
We thank the Deutsche Forschungsgemeinschaft and
the Fonds der Chemischen Industrie for support of this
work.
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