Bis(silylaminodiarylphosphoranylsilylmethyl-C,N)-tin(II) and -lead(II) complexes and their precursors; structures of H(LL′), H(LL″), Sn(LL″)2 and Pb(LL″)2; [LL′]- = [CH(SiMe3)P(Ph)2{double bond, long}

Article abstract of DOI:10.1016/j.jorganchem.2006.02.011

We report a series (a)-(d) of tandem reactions involving the conversion of: (a) 2CH₂(SiMe₃)P(Ph)₂{double bond, long}NSiMe₃ [{A figure is presented}2H(LL′)] (III) into successively [Li(LL′)]₂ (1a) and

Full text of DOI:10.1016/j.jorganchem.2006.02.011

Journal of Organometallic Chemistry 691 (2006) 2748–2756
www.elsevier.com/locate/jorganchem
Bis(silylaminodiarylphosphoranylsilylmethyl-C,N)-tin(II) and
-lead(II) complexes and their precursors; structures of H(LL0), H(LL00),
Sn(LL00)2 and Pb(LL00)2; [LL0]ꢀ = [CH(SiMe3)P(Ph)2@NSiMe3]ꢀ,
[LL'' ]− =
[CH(SiMe )P(Ph){=NSi(Me )C H -1,2}]−
3
2
6 4
a
a,
a,b
Peter B. Hitchcock , Michael F. Lappert *, Zhong-Xia Wang
a
Department of Chemistry, University of Sussex, Brighton BN1 9QJ, UK
Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, PR China
b
Received 19 December 2005; received in revised form 8 February 2006; accepted 8 February 2006
Available online 23 February 2006
Abstract
We report a series (a)–(d) of tandem reactions involving the conversion of: (a) 2CH2(SiMe3)P(Ph)2@NSiMe3 [ 2H(LL0)] (III) into
successively [Li(LL0)]2 (1a) and [Pb(LL0)2] (3a); (b) 1a in turn into
{ [Li(LL00)]2} (2) and
[LiCH(SiMe3)P(Ph){=NSi(Me2)C6H4-1,2]2
[Pb(LL00)2] (4); (c) 1a successively into Sn(LL0)Cl (5) and [Sn(LL00)2] (6); (d)
(1b) into
2Li[CH(SiMe2NEt2)P(Ph)2=NSiMe3]
(3b). Experimental details for the preparation and characterisation (including elemental analysis
Pb[CH(SiMe2NEt2)P(Ph)2=NSiMe3]2
and multinuclear NMR spectra in C6D6 and EI mass spectra) of 1a, 2, 3a, 3b, 4, 6, III (a new synthesis) and IV are provided. The
X-ray structures of crystalline 4, 6, III and IV are presented; those of 1a, 2 and 3a were previously published.
Ó 2006 Elsevier B.V. All rights reserved.
Keywords: 1-Aza-2-phospha(V)allyls; Lithium; Tin(II); Lead(II)
1. Introduction
it was more conveniently prepared by the Staudinger reac-
tion of CH2(SiMe3)PPh2 with Me3SiN3 [6].
1-Aza-2-phospha(V)allyl ligands have featured exten-
sively in coordination chemistry [1,2]. The structure of
the crystalline lithium compound I dates from 1995 [3].
The crystalline neutral donor-free binuclear compound II
has a ladder structure in which the ligand is both N,C-che-
lating and via the 3-C site bridging [1].
In a preliminary communication we reported that the
conjugate acid III of such a ligand (abbreviated as
H[LL0]) is a convenient precursor to its Li(LL0) (1a),
(KLL0) and Pb(LL0)2 (3a) derivatives, and also of two
ortho-cyclosilylated compounds: the [Li(LL00)] (2) and
Pb(LL00)2 (4) complexes, [H(LL00) = IV]; the crystalline 2
and 3a were X-ray-characterised [4]. While III was origi-
nally obtained from [(Me3Si)2NP(Me)Ph2]I and LiBun [5],
Me3Si
PPri2
N
Ph
Ph
Li CMe2
Me2C Li
Pri2P
P
Li
I
H2C
thf
NPh
thf
N
SiMe3
II
SiMe3
N
SiMe2
N
Ph2P
P
CH2
CH2
Ph
SiMe3
SiMe3
III [(HLL')]
IV [H(LL'')]
*
In a follow-up paper we described the synthesis and struc-
tures of the crystalline compounds [Li(LL0)(OEt2)2] and the
Corresponding author. Tel.: +44 1273 678316; fax: +44 1273 677196.
E-mail address: m.f.lappert@sussex.ac.uk (M.F. Lappert).
0022-328X/$ - see front matter Ó 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2006.02.011

P.B. Hitchcock et al. / Journal of Organometallic Chemistry 691 (2006) 2748–2756
2749
SiMe3
N
Ph
C
Ph
Ph
Ph
N
Ph
Ph
H
LiBun, Et2O
P
Et2N(Me)2SiCl
R = H
P
N
R
SiMe3
P
H
C
R
SiMe3
2
MeOH
R = SiMe3
Li
CH2
Et2O
OEt2
Me2SiNEt2
LiBun
10-3 Torr
Me3SiOS(O)2CF3
R = SiMe3
R = SiMe3
SiMe3
H
Me3Si
Ph
H
SiMe3
N
C
N
Ph
C
N
Ph
Ph
N
Ph
P
Li
Li
P
P
Li
P
Ph
Ph
CH
Me3Si
Me3Si
SiMe3
Ph
CH
SiMe3
Si
Me3
Me
2SiNEt2
V
1b
Scheme 1. [7].
binuclear ether-free compound V, as well as the conversion
of the former into: (i) CH(SiMe3)2P(Ph)2@NSiMe3 and (ii)
the phosphinimine CH2{SiMe2(NEt2)}P(Ph)2@NSiMe3
and its lithium salt 1b, as summarised in Scheme 1 [7].
We now report details not available in our earlier com-
munication [4] regarding compounds 1a, 2 and 3a [5], and
extensions to the synthesis and characterisation ofꢀother
Sn(II) and Pb(II) complexes of the ligands [LL0] and
[LL00]ꢀ, as well as the structures of the crystalline pro-
ligands III [H(LL0)] and IV [H(LL00)].
(3b), [Pb(LL00)2] (4) and [Sn(LL00)2] (6) is summarised in
Scheme 2. Thus, treatment of H(LL0) (III) [7] with LiBun
afforded (i in Scheme 2) 1a. From the latter or 1b [7] and
PbCl2 there was obtained (ii in Scheme 2) 3a or 3b, respec-
tively. Treatment of 1a with LiBun yielded (iii in Scheme 2)
2, which with PbCl2 gave (ii in Scheme 2) 4. Whereas
[Li(LL00)2] (2) was thus an effective ligand transfer reagent
for securing the homoleptic Pb(II) compound 4, curiously this
proved not to be the case (possibly for steric reasons) for the
tin(II) analogue 6. The latter was, however, conveniently
obtained by treating [Li(LL0)]2 (1a) successively (iv and v in
Scheme 2) with equivalent portions of SnCl2 and LiBun.
The transformatiꢀon of the ligand [LL0]ꢀ (VIa) into the
cyclosilylated [LL00] (VII) has previously been explained
[4] by proposing that the reaction of Li(LL0) (1a) with
LiBun proceeded via an ortho-lithiated intermediate which
underwent an intramolecular displacement of Meꢀ at sili-
con by the o-carbanion thus generating 1/2[Li(LL00)]2 (2)
and LiMe [4]; the reaction was shown to be catalytic in
LiBun, interpreted as due to the eliminated LiMe formed
in the initiation step being able to participate in the prop-
agation cycle. We now suggest that a similar mechanism
is operative in step v of Scheme 2 in the conversion of 1a
2. Results and discussion
2.1. Objectives
As indicated in the preceding section, we have previ-
ously reported on complexes derived from the 1-aza-2-
phospha(V)allyl ligands [LL]ꢀ (VI) and [LL00]ꢀ (VII)
[4,6,7]. The principal focus of this paper is on the synthesis
and structures of the corresponding homoleptic tin(II) and
lead(II) complexes, M(LL0)2 and M(LL00)2.
SiMe3
SiMe2
iv
v
into 6 ½1a ! SnClðLL0Þ ð5Þ ! 1=2SnClðLL00Þ2 ð6Þꢁ. The evi-
dence for the intermediacy of 5 rests on mass spectral evi-
dence (molecular ion [5]+ observed on the volatiles-free
N
N
Ph2P
P
CH
CH
Ph
1
sample) and the H NMR spectrum which showed that
SiMe2R
SiMe3
the sample in C6D6 had the appropriate signals for 5, albeit
with minor impurities; attempts to crystallise 5 from vari-
ous solvents (C6H14, Et2O or C6H6) failed. As for step v,
we suggest that 5 with LiBun forms a transient ortho-lithi-
ated intermediate 7, which upon cyclosilylation generates 8,
which disproportionates yielding 1/2(6) with oligomeric
VIa R = Me
VII
VIb R = NEt2
2.2. Synthesis of lithium, tin(II) and
lead(II)silyliminodiarylphosphoranylsilylmethyls
SnMe2, SnBun or SnCl2 as coproduct. Metallation of an
2
iminophosphorane was first demonstrated by Stuckwisch,
as in Ph3P@NPh with successively LiPh, CO2 and H2O giv-
ing Ph2P(O)C6H4CO2H-2 [8].
The preparation of compounds [Li(LL0)]2 (1a), [Li(LL00)]2
(2), [Pb(LL0)2] (3a),
[Pb{CH(SiMe2NEt2)P(Ph)2=NSiMe3}2]

2750
P.B. Hitchcock et al. / Journal of Organometallic Chemistry 691 (2006) 2748–2756
SiMe3
N
Me2
Si
SiMe3
SiMe2
N
N
N
i
iii
Ph2P
2
ii
Ph2P
Li
P
P
Li
Pb
CH2
Ph
CH
CH
Ph
CH
2
2
SiMe3
2
SiMe3
SiMe3
SiMe3
III
1a, 85%
2, 69%
4, 48 %
iv
2
ii
Me2
Si
SiMe3
SiMe3
N
SiMe3
N
N
N
ii
v
Ph2P
2
PPh2
Li
P
Pb
Ph2P
SnCl
Sn
CH
CH
CH
SiMe2R
3a R = Me, 50 %
3b R = NEt2, 49 %
Ph
CH
2
SiMe2NEt2
2
SiMe3
SiMe3
1b [7]
5 (not isolated pure)
6, 54 %
Scheme 2. Synthesis of (silyliminodiarylphosphoranylsilylmethyl-C,N)tin(II) or -lead(II) complexes 3-6 and their lithium precursors 1a, 1b [7] and 2.
Reagents and conditions: (i) 2LiBun, hexane, ꢀ20 °C to 20 °C; (ii) PbCl2, Et2O, ꢀ45 °C to ca. 20 °C, 15 h; (iii) 2LiBun, hexane, reflux, 4 h; (iv) 2SnCl2, Et2O,
ꢀ45 °C to ca. 20 °C, 15 h; (v) 2LiBun, ꢀ78 °C to ca. 20 °C, 4 h.
The 31P{1H} NMR spectra of 3a, 3b and 4 showed sing-
Me
lets at d 19.5, 17.05 and 40.3, respectively, with satellites
SiMe2
due to 2J(31PA207Pb). The 207Pb{1H} NMR spectra
SiMe2
N
revealed triplets centred at d 2787.6 (3a), 2936.9 (3b) and
1998.3 (4). Thus, it is evident that 3a and 3b had the closer
31P and 207Pb chemical shifts. This indicates that this dis-
parity for 4 is determined principally by the fused bicyclic
structure of the ligand in 4, and that the different substitu-
ents on silicon in 3a and 3b have little influence on these
parameters. The EI-MS of each of 3a, 3b and 4 gave a weak
parent ion.
N
SnCl
SnX
P
P
CH
CH
Ph
Ph
SiMe3
SiMe3
8 X = Me, Bun or Cl
7
Crystalline compounds 1a, 2, 3a, 3b, 4 and 6 gave satisfac-
tory microanalytical data (C, H, N) as well as 1H (for 1a, see
also [4]), 13C{1H}, 31P{1H}, 7Li{1H} (for 1a and 2), 29Si{1H}
(for 6), 119Sn{1H} (for 6) and 207Pb{1H} (for 3a, 3b and 4)
The 119Sn{1H} NMR spectrum of 6 displayed a triplet
due to coupling with two equivalent phosphorus atoms,
2J(119SnA31P) = 162.5 Hz. The 31P{1H} spectrum showed
NMR spectra; for such data on 1b, see [7]. The Li{1H}
7
a
singlet with satellites due to 119/117Sn coupling,
2J(31PA119/117Sn) = 162.6 Hz. The 29Si{1H} NMR spec-
trum comprised two sets of signals: the first, a singlet with
119/117Sn satellites, 2J(29SiA119/117Sn) = 53.5 Hz; and the
second, a doublet due to coupling to phosphorus,
2J(29SiA31P) = 7.3 Hz. The EI-mass spectrum of 6 showed
a weak [Sn(LL00)2]+ parent and a strong [Sn2(LL00)2-2]+ ion;
the latter may have arisen from a recombination of frag-
ments in the mass spectrometer.
NMR spectral chemical shift in C6D6 for 1b (d ꢀ0.76) was
at significantly lower frequency than for Li(LL0) (1a) or
[Li(LL00)]2 (2), which may be due to a close Et2Nꢂ ꢂ ꢂLi contact
in 1b. Each of the two methyl groups attached to the silicon
atom of the five-membered CCPNSi ring of each of the com-
pounds [Li(LL00)]2 (2), [Pb(LL00)2] (4) and [Sn(LL00)2] (6) was
magnetically distinct as evident from both their 1H
and13C{1H} NMR spectra in C6D6, one being endo- and
the other exo- in conformation. Likewise, such spectra
showed that the two silylmethyl groups of the SiMe2NEt2
2.3. The X-ray structures of the crystalline compounds 4, 6,
III and IV
[Pb{CH(SiMe NEt )P(Ph) =NSiMe } ]
moiety of
(3b) are diastero-
3 2
2
2
2
topic as illustrated in 9, a Newman projection taken through
the a-CASi vector.
The molecular structure of the crystalline lead(II) com-
plex [Pb(LL00)2] (4) is illustrated in Fig. 1 and selected geo-
metric parameters are listed in Table 1. The four-
coordinate lead atom is the centre of a distorted trigonal
bipyramid, the N1 and N2 atoms axial and the C1 and
C19 atoms with the stereochemically active lone pair occu-
pying the equatorial sites. The central five-membered ring
of each Pb(LL00) moiety is coplanar with its fused ortho-
phenylene ring. The dihedral angle between: (a) the
P
N
H
Me
Pb
Me
9

P.B. Hitchcock et al. / Journal of Organometallic Chemistry 691 (2006) 2748–2756
2751
Fig. 1. Molecular structure of [Pb(LL00)2] (4).
˚
P1N1Si1C2C7 and the C1P1N1 planes is 56.23(0.28)°; (b)
the C1P1N1 and C1N1Pb planes is 13.38(0.54)°; (c) the
C1N1Pb and PbC19N2 planes is 87.29(0.27)°; (d) the
PbC19N2 and the C19N2P2 planes is 17.38(0.17)°. The
and Si4 at ca. 1.42, 1.23 and 1.55 A. The P1 and P2 atoms
˚
are ca. 0.22 and 0.28 A out of the C1N1Pb and C19N2Pb
planes, respectively.
The mean PbAN dis0tance in 4 is close to the
˚
˚
lead atom is ca. 0.49 A on one side of the C1P1N1 plane
2.678 0.024 A of [Pb(LL )2] (3a) [4]; both are appropri-
˚
with C2, Si1 and Si2 at ca. 1.46, 1.20 and 1.48 A on the
ate for a PbAN coordinate bond, being significantly
opposi0t0e side; the corresponding values for the other
longer than in the equally four-coordinate Pb(II)
˚
Pb(LL ) moiety are 0.635 A for the Pb atom on one side
complex [Pb{N(SiMe3)C(C6H4CF3-4)N(SiMe3)}2] (VIII) or
of the C19N2P2 plane with on the opposite side C26, Si3
[Pb{N(SiMe3)P(Ph)2N(SiMe3)}2] (IX) of a mean 2.442 or
2.465 A, respectively [9]. The PAN bond length, e.g.,
˚
Table 1
P1AN1, and the ligand bite angles in 4, e.g.,
N1APbAC1, are of a similar order of magnitude, as
˚
Selected bond lengths (A) and angles (°) for 4
˚
Bond length (A)
˚
the mean values in IX, 1.596 A and 63.0°, respectively
PbAC(1)
PbAC(19)
PbAN(1)
2.429(7)
2.453(8)
2.594(6)
2.607(6)
1.599(7)
1.762(7)
1.815(11)
1.807(8)
1.582(6)
1.748(8)
1.811(8)
P(2)AC(26)
Si(1)AN(1)
Si(1)AC(14)
Si(1)AC(15)
Si(1)AC(7)
Si(2)AC(1)
Si(3)AN(2)
Si(3)AC(33)
Si(3)AC(32)
Si(3)AC(31)
Si(4)AC(19)
1.815(9)
1.692(7)
1.831(10)
1.851(11)
1.902(14)
1.849(7)
1.704(6)
1.840(10)
1.884(9)
1.904(9)
1.859(8)
˚
[9], or in 3a, 1.569(4) A [4], the PAN bond in 3a or 4
is evidently longer than appropriate for a formal double
PbAN(2)
bond, as in CH2[P(Ph)2@NSiMe3]2 (X) with l(P@N)
P(1)AN(1)
P(1)AC(1)
P(1)AC(2)
P(1)AC(8)
P(2)AN(2)
P(2)AC(19)
P(2)AC(20)
˚
˚
1.536(2) A [10] or 1.539(3) A in P(Ph)2{C6H4(CH2-
SiMe3)-2}{@N(SiMe3)} [11]. The PAC(H)SiMe3 bond in
˚
3a [1.759(5) A] [4] or 4 is somewhat shorter than the
˚
˚
1.822 0.003 A in X [10] or the 1.807 0.002 A in
A[CH2P(Ph)2@N(SiMe3)]2 (XI) [12].
The crystalline tin(II) complex Sn(LL00)2 (6) is isomor-
phous with 4 and hence description of its molecular struc-
ture, illustrated in Fig. 2 with selected bond lengths and
angles shown in Table 2, is restricted to parameters incorpo-
rating the tin atom. The mean SnAN distance in 6 is
appropriate for a Sn N coordinate bond, being some-
Bond angle (°)
C(1)APbAC(19)
C(1)APbAN(1)
C(19)APbAN(1)
C(1)APbAN(2)
C(19)APbAN(2)
N(1)APbAN(2)
N(1)AP(1)AC(1)
N(1)AP(1)AC(8)
C(1)AP(1)AC(8)
N(1)AP(1)AC(2)
P(1)AN(1)ASi(1)
P(1)AN(1)APb
P(2)AN(2)APb
92.7(3)
66.2(2)
90.8(2)
90.2(2)
65.2(2)
146.0(2)
109.5(4)
111.7(4)
110.6(4)
104.7(5)
116.7(5)
131.4(3)
90.4(3)
C(1)AP(1)AC(2)
C(8)AP(1)AC(2)
N(2)AP(2)AC(19)
N(2)AP(2)AC(20)
C(19)AP(2)AC(20)
N(2)AP(2)AC(26)
C(19)AP(2)AC(26)
C(20)AP(2)AC(26)
P(2)AC(19)APb
P(1)AC(1)APb
115.0(4)
105.2(4)
110.0(4)
112.1(4)
108.4(4)
103.8(4)
117.1(4)
105.4(4)
91.9(3)
˚
what longer than the mean of 2.362 A in
[Sn{N(SiMe3)P(Ph)2N(SiMe3)}2] (XII) [9]. The ligand bite angle
in 6, (e.g., N1ASnAC1) is similar to the mean of 65.5° in XII
˚
[9]. The P1 and P2 atoms are ca. 0.20 and 0.28 A out of the
92.4(3)
Si(3)AN(2)APb
P(1)AC(1)ASi(2)
Si(2)AC(1)APb
134.5(3)
124.4(4)
109.4(3)
C1N1Sn and C19N2Sn planes, respectively.
Single crystals of CH2(SiMe3)P(Ph)2@N(SiMe3), H(LL0),
III, were grown from a mixture of methylcyclohexane and

2752
P.B. Hitchcock et al. / Journal of Organometallic Chemistry 691 (2006) 2748–2756
Fig. 2. Molecular structure of [Sn(LL00)2] (6).
Table 2
˚
Selected bond lengths (A) and angles (°) for 6
˚
Bond length (A)
SnAC(1)
SnAC(19)
SnAN(1)
2.335(6)
2.353(6)
2.480(6)
2.525(6)
1.599(6)
1.751(6)
1.811(7)
1.812(8)
1.592(6)
1.749(7)
1.817(7)
1.830(7)
Si(1)AN(1)
Si(1)AC(15)
Si(1)AC(14)
Si(1)AC(7)
Si(2)AC(1)
Si(3)AN(2)
Si(3)AC(33)
Si(3)AC(32)
Si(3)AC(31)
Si(4)AC(19)
C(2)AC(7)
C(26)AC(31)
1.705(6)
1.841(9)
1.866(9)
1.886(10)
1.870(6)
1.711(6)
1.847(9)
1.861(9)
1.899(8)
1.853(7)
1.401(11)
1.395(9)
SnAN(2)
P(1)AN(1)
P(1)AC(1)
P(1)AC(8)
P(1)AC(2)
P(2)AN(2)
P(2)AC(19)
P(2)AC(20)
P(2)AC(26)
Bond angle (°)
C(1)ASnAC(19)
C(1)ASnAN(1)
C(19)ASnAN(1)
C(1)ASnAN(2)
C(19)ASnAN(2)
N(1)ASnAN(2)
N(1)AP(1)AC(1)
N(1)AP(1)AC(8)
C(1)AP(1)AC(8)
N(1)AP(1)AC(2)
C(1)AP(1)AC(2)
C(8)AP(1)AC(2)
N(2)AP(2)AC(19)
N(2)AP(2)AC(20)
C(19)AP(2)AC(20)
N(2)AP(2)AC(26)
93.8(2)
68.4(2)
89.3(2)
88.8(2)
67.5(2)
146.73(18)
107.9(3)
112.5(3)
110.8(3)
103.5(4)
117.1(3)
104.9(3)
108.4(3)
112.9(3)
108.6(3)
103.9(3)
C(19)AP(2)AC(26)
C(20)AP(2)AC(26)
P(2)AC(19)ASn
C(31)AC(26)AP(2)
N(1)ASi(1)AC(7)
N(2)ASi(3)AC(31)
P(1)AN(1)ASi(1)
P(1)AN(1)ASn
Si(1)AN(1)ASn
P(2)AN(2)ASi(3)
P(2)AN(2)ASn
Si(3)AN(2)ASn
P(1)AC(1)ASi(2)
P(1)AC(1)ASn
117.6(3)
105.6(3)
92.0(3)
111.1(5)
97.9(4)
97.9(3)
114.6(4)
90.6(2)
131.2(3)
114.6(3)
89.8(2)
134.3(3)
123.4(4)
91.9(3)
110.0(3)
Fig. 3. Molecular structure of H(LL0) (III).
Table 3
˚
Selected bond lengths (A) and angles (°) for III
˚
Bond length (A)
Si(2)AC(1)ASn
PAN
PAC(1)
PAC(14)
1.544(2)
1.803(2)
1.818(2)
PAC(8)
Si(1)AC(1)
Si(2)AN
1.825(2)
1.892(2)
1.680(2)
diethyl ether (9:1) at ꢀ25 °C. The molecular structure is
shown in Fig. 3, selected geometric parameters being listed
in Table 3. The phosphorus atom is in a distorted tetrahedral
environment, the NAPAC1 and C8APAC14 bond angles
being the widest and narrowest, respectively; the former is
Bond angle (°)
NAPAC(1)
NAPAC(14)
C(1)APAC(14)
NAPAC(8)
117.28(11)
109.95(10)
104.64(11)
114.21(10)
C(1)APAC(8)
C(14)APAC(8)
PANASi(2)
106.17(10)
103.29(10)
143.89(13)
119.60(3)
PAC(1)ASi(1)

P.B. Hitchcock et al. / Journal of Organometallic Chemistry 691 (2006) 2748–2756
2753
much wider than the NAPACsp3 bond angle in the strained
four-membered ring of [Li(LL0)(OEt2)2] [110.2(1)°] [7], 4 or
6 and the 114.7(3) in the open-chain compound XI [12].
The PAC(H)2 bond length is close to that of the PAC(H)2
difference between the two, attributable to the silylphenyla-
tion in IV, resides in the environment at the nitrogen atom,
the PAN bond being appreciably longer in IV than III and
the PANASi1 bond angle significantly narrower in IV;
however both these parameters in IV are close to the corre-
sponding values in 4 and 6.
˚
bond of 1.807 0.002 A in A[CH2P(Ph)2@N(SiMe3)]2
(XI), but much longer than in 4, 6 or [Li(LL0)(OEt2)2],
˚
˚
1.702(3) A [7]. The PAN bond in the latter, 1.592(2) A, 4
and 6 are of similar magnitude but much longer than the
3. Experimental
˚
1.537 0.007 A of XI [12] which is close to the value in III.
All reactions were performed under argon using stan-
dard Schlenk techniques. The THF and diethyl ether were
dried using sodium-benzophenone; hexane and pentane
were dried using sodium–potassium alloy. The compounds
Li(LL00) (1b) [4] and HLL0 (III) [7] were prepared by pub-
lished methods. The NMR spectra were recorded on Bru-
ker AC-P250, DPX 300, WM-360 or AMX-500
instruments, and the solvent resonances were used as the
internal references for 1H and13C{1H} spectra; H3PO4
(85% aqueous solution), SnMe4 and PbMe4 were the exter-
nal references for 31P{1H}, 119Sn{1H} and 207Pb{1H}
NMR spectra, respectively; unless other stated, spectra
were recorded at 298 K in C6D6 at 360.1 (1H), 62.9 (13C),
97.3 (7Li), 99.4 (29Si), 101.3 (31P), 93.3 (119Sn) or 52.1
CH (SiMe )P(Ph){=NSi(Me )C H -1,2}
Single crystals of
,
2
3
2
6 4
H(LL00), IV, were obtained adventitiously from the in situ
prepared Pb complex Pb(LL00)2 under aerobic conditions.
The molecular structure is illustrated in Fig. 4, with some
geometric parameters listed in Table 4. The bicyclic moiety,
comprising the ortho-phenylene ring and its fused
C8PNSiC9 neighbour are almost coplanar. The phospho-
rus atom is in a distorted tetrahedral environment with
the NAPAC1 and the NAPAC8 angles the widest and nar-
rowest, respectively. The former is only very slightly nar-
rower than the corresponding NAPACsp3 angle of III.
Likewise, the PAC1 [PAC(H)2] bond lengths in the two
compounds are virtually identical. The principal points of
(
207Pb) MHz. Elemental analyses were carried out by
Medac Ltd., Brunel University. Melting points were deter-
mined under argon in sealed capillaries on an electrother-
mal apparatus and were uncorrected.
3.1. Synthesis of [Li{CH(SiMe3)P(Ph)2=NSiMe3}] (1a)
A solution of LiBun (2.3 cm3 of a 1.6 mol dmꢀ3 solution
in hexane, 3.68 mmol) was added dropwise to a stirred
solution of HLL0 (III) (1.27 g, 3.54 mmol) in hexane
(30 cm3) at ꢀ20 °C. The solution was allowed to warm to
room temperature and was stirred for 3 h. The solution
was concentrated in vacuo to ca. 3 cm3, yielding colourless
crystals of compound 1a (85%), m.p. 135–138 °C. 1H
NMR: d 0.10 (s, 9 H, SiMe3), 0.13 (s, 9 H, SiMe3), 0.17
(d, 1 H, J = 13.8 Hz, CH); 7.19 (s), 7.21 (s), 7.89 (m)
(Ph); 13C{1H} NMR: d 3.68 (d, J = 3.5 Hz, SiMe3), 4.13
(d, J = 4.6 Hz, SiMe3), 14.92 (d, J = 68.6 Hz, CH),
127.65 (d, J = 10.3 Hz), 128.28 (s), 132.12 (d, J = 9.8 Hz),
147.93 (d, J = 84.2 Hz) (Ph); 7Li{1H} NMR: d 2.23;
31P{1H} NMR (101.3 MHz): d 33.32. EI-MS [m/z (%)
(assignment)]: 359 (32) [M ꢀ Li + 1]+, 344 (100)
[M ꢀ MeALi+1]+, 272 (26) [M ꢀ LiACHSiMe3]+, 135
(29) [M ꢀ LiA2SiMe3APh]+, 73 (22) [SiMe3]+. Elemental
analysis for C19H29LiNPSi2: found % (calculated %), C
62.3 (62.4), H 8.02 (8.00), N 3.95 (3.83).
Fig. 4. Molecular structure of H(LL00) (IV).
Table 4
˚
Selected bond lengths (A) and angles (°) for IV
˚
Bond length (A)
PAN
1.587(5)
1.779(6)
1.816(6)
1.819(6)
Si(1)AN
1.689(5)
1.884(6)
1.887(6)
1.387(8)
PAC(1)
PAC(2)
PAC(8)
Si(1)AC(9)
Si(2)AC(1)
C(8)AC(9)
3.2. Synthesis of [LiCH(SiMe3)P(Ph){=NSi(Me2)C6H4-1,2}]2 (2)
Bond angle (°)
NAPAC(1)
NAPAC(2)
C(1)APAC(2)
NAPAC(8)
C(1)APAC(8)
C(2)APAC(8)
116.0(3)
NASi(1)AC(9)
PANASi(1)
PAC(1)ASi(2)
C(9)AC(8)AP
C(8)AC(9)ASi(1)
99.5(3)
112.8(3)
116.3(3)
110.4(4)
112.0(4)
A solution of LiBun (2.8 cm3 of a 1.6 mol dmꢀ3 solution in
hexane, 4.38 mmol) was added to a stirred solution of
Li(LL0) (1a) (1.60 g, 4.38 mmol) in hexane (30 cm3) at room
temperature. The solution was stirred for 1 h and then
refluxed for 4 h. The pale yellow solution was concentrated
113.0(3)
106.4(3)
105.1(3)
109.0(3)
106.9(3)

2754
P.B. Hitchcock et al. / Journal of Organometallic Chemistry 691 (2006) 2748–2756
to ca. 3 cm3, yielding colourless crystals of compound 2
(1.05 g, 69%), m.p. 214–217 °C. 1H NMR: d ꢀ0.02 (s, 9 H,
SiMe3), 0.32 [s, 3 H, Si(CH3)Me], 0.59 (s, 3 H, Si(Me)CH3),
0.92 (d, 1 H, J = 4.9 Hz, CH), 7.03–7.15 (m, 5 H, Ph), 7.44–
7.56 (m, 2 H, C6H4) and 7.77–7.83 (m, 2 H, C6H4); 13C{1H}
NMR (75.5 MHz): d 2.28 (d, J = 5.1 Hz, Me), 2.77 (d,
J = 4.0 Hz, Me), 2.91 (d, J = 2.1 Hz, Me), 6.50
(d,J = 86.6 Hz); 127.80 (s), 128.37 (d, J = 10.8 Hz), 128.75
(d, J = 5.5 Hz), 128.93 (s), 129.25 (d, J = 2.9 Hz), 129.58
(d, J = 9.8 Hz), 130.03 (d, J = 2.6 Hz), 130.79 (d,
J = 15.9 Hz), 140.81 (d, J = 86.9 Hz), 147.01 (d,
J = 29.0 Hz), 148.57 (d, J = 84.6 Hz); 7Li{1H} NMR
(97.3 MHz): d 2.05; 31P{1H} NMR: d 48.70. EI-MS [m/z
(%) (assignment)]: 342 (58) [M ꢀ Li]+, 328 (44)
[M ꢀ MeALi + 1]+, 256 (100) [M ꢀ LiACHSiMe3]+, 180
(25) [PhP(CH)NSiMe2]+, 137 (17) [PhP(CH)N]+. Elemental
analysis for C36H50Li2N2P2Si4: found % (calculated %), C
60.9 (61.8), H 7.27 (7.21), N 3.15 (4.01).
128.13 (d, J = 11.1 Hz), 130.32 (s), 130.57 (d, J = 13.0 Hz),
131.15 (d, J = 10.2 Hz), 131.60 (d, J = 10.3 Hz), 131.87 (d,
J = 10.6 Hz), 141.85 (d, J = 82.8 Hz), 143.17 (d, J =
86.5 Hz) (Ph); 31P{1H} NMR: d 17.05 (s, with satellite peaks,
J = 304.7 Hz); 207Pb{1H} NMR: d 2936.9 (t, J = 303 Hz).
EI-MS [m/z (%) (assignment)]: 1038 (0.1%) ([M]+). Elemen-
tal analysis for C44H72N4P2PbSi4: found % (calculated %), C
50.8 (50.9), H 7.16 (6.99), N 5.47 (5.39).
3.5. Synthesis of [Pb(CH(SiMe3)P(Ph){=NSi(Me2)C6H4-1,2})2]
(4)
Complex
4
was prepared similarly as for 3a.
(2) (0.57 g, 1.63
[LiCH(SiMe3)P(Ph){=NSi(Me2)C6H4-1,2}]2
mmol) was treated with PbCl2 (0.23 g, 0.82 mmol) to pro-
duce colourless crystals of complex 4 (0.35 g, 48%), m.p.
1
90–92 °C. H NMR: d 0.31 (s, 18 H, SiMe3), 0.53 (s, 6 H,
SiMe), 0.69 (s, 6 H, SiMe), 1.43 (d, 2H, J = 9.5 Hz, CH);
7.06–7.25 (m), 7.54–7.65 (m) (Ph + C6H4). 13C{1H} NMR:
d 1.63 (d, J = 6.2 Hz, SiMe), 2.01 (d, J = 3.9 Hz, SiMe3),
2.39 (d, J = 2.4 Hz, SiMe), 28.22 (d, J = 61.9 Hz, CH);
127.05 (d, J = 13.4 Hz), 128.54 (d, J = 11.2 Hz), 129.14 (d,
J = 10.2 Hz), 129.66 (d, J = 2.8 Hz), 129.87 (d, J =
2.8 Hz), 131.10 (d, J = 16.5 Hz), 141.26 (d, J = 86.9 Hz),
147.96 (d, J = 30.8 Hz), 153.65 (d, J = 77.0 Hz)
(Ph + C6H4); 31P{1H} NMR: d 40.3 (s, with satellite peaks,
3.3. Synthesis of [Pb{CH(SiMe3)P(Ph)2=NSiMe3}2] (3a)
PbCl2 (0.37 g, 1.33 mmol) was added at ꢀ45 °C to a stir-
red diethyl ether solution of
[Li{CH(SiMe3)P(Ph)2=NSiMe3}]
(1a), prepared from CH2(SiMe3)P(Ph)2@NSiMe3 (0.96 g,
2.67 mmol) and LiBun (1.7 cm3 of a 1.6 mol dmꢀ3 solution
in hexane, 2.72 mmol). The mixture was allowed to warm
to room temperature and was stirred overnight. Volatiles
were removed in vacuo. The residue was extracted with pen-
tane and the extract was filtered. The filtrate was concen-
trated in vacuo to afford yellow crystals of complex 3a
J = 311.8 Hz). 207Pb{1H} NMR:
d
1998.3 (t, J =
313.3 Hz). EI-MS [m/z (%) (assignment)]: 892 (5 %) ([M]+).
Elemental analysis for C36H50N2P2PbSi4: found % (calcu-
lated %), C 47.9 (48.5), H 5.65 (5.65), N 3.09 (3.14).
1
(0.62 g, 50%), m.p. 148–152 °C. H NMR: d ꢀ0.01 (s, 18
3.6. Synthesis of
(6)
[Sn(CH(SiMe3)P(Ph){=NSi(Me2)C6H4-1,2})2]
H, SiMe3), 0.20 (s, 18 H, SiMe3), 1.37 (d, 2 H, J = 15.8 Hz,
CH); 7.00–7.05 (m), 7.15–7.22 (m), 7.64–7.69 (m), 7.79–
7.85 (m) (Ph); 13C{1H} NMR: d 3.26 (d, J = 4.2 Hz, SiMe3),
4.01 (d, J = 3.8 Hz, SiMe3), 39.47 (d, J = 70.5 Hz, CH);
128.20 (d, J = 4.3 Hz), 128.37 (d, J = 3.9 Hz), 130.78 (s),
131.03 (d, J = 10.5 Hz), 131.92 (d, J = 10.4 Hz), 140.20 (d,
J = 83.7 Hz), 144.17 (d, J = 84.9 Hz) (Ph); 31P{1H} NMR:
d 19.5 (s, with satellite peaks, J = 308 Hz); 207Pb{1H}
NMR: d 2787.6 (t, J = 306 Hz). EI-MS [m/z (%) (assign-
ment)]: 924 (1%) ([M]+). Elemental analysis for
C38H58N2P2PbSi4: found % (calculated %), C 49.2 (49.4),
H 6.36 (6.32), N 2.90 (3.03).
SnCl2 (0.58 g, 3.05 mmol) was added to a diethyl ether
(ca. 30 cm3) solution of
(1a)
[Li{CH(SiMe3)PPh2=NSiMe3}]
(1.10 g, 3.01 mmol) at ꢀ78 °C with stirring. The mixture
was allowed to warm to room temperature and was stirred
overnight. The stirred mixture was recooled to ꢀ78 °C and
LiBun (1.9 cm3 of
a
1.6 mol dmꢀ3 hexane solution,
3.04 mmol) was added dropwise. Stirring was continued
for 4 h at room temperature. Solvent was removed in vacuo
and the solid residue was extracted with hexane. The
extract was filtered and the filtrate was concentrated to
afford colourless crystals of 6 (0.65 g, 54%), m.p. 183–
3.4. Synthesis of [Pb{CH(SiMe2NEt2)P(Ph)2=NSiMe3}2] (3b)
1
186 °C. H NMR: d 0.27 (s, 18 H, SiMe3), 0.43 (s, 6 H,
Complex 3b was obtained similarly as for 3a.
[Li{CH(SiMe2NEt2)PPh2=NSiMe3}] (1b) (0.84 g, 1.99 mmol)
was treated with PbCl2 (0.27 g, 0.97 mmol) to yield the yel-
low crystalline complex 3b (0.51 g, 49%), m.p. 148–152 °C.
1H NMR: d 0.02 (s, 18 H, SiMe3), 0.17 (s, 6 H, SiMe), 0.28
(s, 6 H, SiMe), 1.03 (t, 12 H, J = 7.0 Hz, Me), 1.28 (d, 2 H,
J = 14.6 Hz, CH), 2.97 (m, 8 H, NEt2); 7.05 (s), 7.20–7.28
(m), 7.73–7.77 (m), 7.85–7.90 (m) (Ph); 13C{1H} NMR: d
0.48 (d, J = 2.8 Hz, SiMe), 2.36 (d, J = 3.2 Hz, SiMe), 3.25
(d, J = 4.5 Hz, SiMe3), 15.79 (s, NCH2), 39.20 (d,
J = 70.9 Hz, CH), 40.13 (s, Me); 128.03 (d, J = 16.3 Hz),
SiMe), 0.69 (s, 6 H, SiMe), 1.77 (d, 2H, J = 10.8 Hz,
CH); 6.92–7.02 (m), 7.39–7.49 (m) (Ph + C6H4); 13C{1H}
NMR: d 0.74 (d, J = 6.2 Hz, SiMe), 1.60 (d, J = 3.8 Hz,
SiMe3), 2.63 (d, J = 2.1 Hz, SiMe), 18.94 (d, J = 54.7 Hz,
CH); 127.47 (d, J = 13.5 Hz), 128.55 (d, J = 10.0 Hz),
128.71 (d, J = 11.5 Hz), 129.05 (d, J = 10.5 Hz), 129.78
(d, J = 2.6 Hz), 129.91 (d, J = 2.5 Hz), 131.62 (d, J =
16.5 Hz), 140.55 (d, J = 85.7 Hz), 148.31 (d, J = 75.3 Hz),
149.71 (d, J = 30.2 Hz) (Ph + C6H4); 31P{1H} NMR: d
44.9 (s, with satellite peaks, J = 162.3, 155.5 Hz);
119Sn{1H} NMR: d ꢀ121.4 (t, J = 162.6 Hz); 29Si{1H}

P.B. Hitchcock et al. / Journal of Organometallic Chemistry 691 (2006) 2748–2756
2755
NMR: d ꢀ0.42 (s, with satellite peaks, J = 53.5 Hz), 8.53
(d, J = 7.3 Hz). EI-MS [m/z (%) (assignment)]: 804 (1%)
([M]+), 920 (38%) ([Sn2(LL00)2-2]+). Elemental analysis for
C36H50N2P2Si4Sn: found % (calculated %), C 53.0 (53.8),
H, 6.18 (6.27), N, 3.13 (3.48).
(d, J = 9.2 Hz), 128.42 (d, J = 11.4 Hz), 129.81 (d, J =
2.9 Hz), 130.45 (d, J = 9.5 Hz), 130.63 (d, J = 2.8 Hz),
131.61 (d, J = 17.9 Hz), 138.67 (d, J = 92.1 Hz), 147.07 (d,
J = 80.7 Hz), 152.30 (d, J = 33.3 Hz); 31P{1H} NMR: d
32.0. X-ray quality crystals were grown from a hexane
solution.
3.7. A new synthesis of CH2(SiMe3)P(Ph)2@NSiMe3 (III)
(by P.G.H. Uiterweerd)
3.9. Crystallographic data and structure refinement for 3a, 6,
III and IV
Compound 1a (1.38 g, 3.78 mmol) was dissolved in hex-
ane (20 cm3) and cooled to 0 °C. Methanol (0.2 cm3,
4.94 mmol) was added dropwise. The reaction mixture
was allowed to warm to room temperature and then stirred
for 1 h. The mixture was filtered and the volatiles from the
filtrate were removed in vacuo, yielding III (1.22 g, 90%) as
Diffraction data were collected on an Enraf Nonius
CAD4 diffractometer using monochromated Mo Ka radia-
˚
tion (k = 0.71073 A) with crystals sealed in capillaries for
4, 6 and IV, or for III coated in oil and directly mounted
on the diffractometer under a stream of cold nitrogen gas.
The structures were refined on all F2 using SHELXL-97 [13].
Crystallographic data for the structural analysis have been
deposited with the Cambridge Crystallographic Data Cen-
tre, CCDC Nos. 289180 (4), 189181 (6), 289178 (III) and
289179 (IV). Copies of the data can be obtained free of
charge on application to The Director, CCDC, 12 Union
Road, Cambridge CB2 1EZ, UK (fax: +44 1223 336 033;
e-mail: deposit@ccdc.cam.ac.uk, www: http://www.ccdc.ca-
m.ac.uk (see Table 5).
1
a white solid, m.p. 38.5–41.0 °C. H NMR (300.1 MHz): d
0.01 (s, 9 H, CSiMe3), 0.31 (s, 9 H, NSiMe3), 1.44 [d, 1 H,
2J(1H,31P) = 15.2 Hz, CH], 7.04–7.08 (m, 6 H, Ph), 7.54–
7.60 (m, 4 H, Ph); 31P{1H} NMR (121.1 MHz): d 0.46
(s). X-ray quality crystals were obtained from a mixture
of methylcyclohexane:diethyl ether (9:1) at ꢀ25 °C.
CH (SiMe )P(Ph){=NSi(Me )C H -1,2}
3.8. Synthesis of
(IV)
2
3
2
6 4
PbCl2(0.29 g, 1.04 mmol) was added to a stirred solution
of [Li(LL00)]2 (2) (0.75 g, 2.15 mmol) in diethyl ether (ca.
20 cm3) at ꢀ40 °C. The mixture was stirred for ca. 12 h at
room temperature. Volatiles were removed in vacuo and
the residue was extracted with pentane. The extract was fil-
tered in the open laboratory and the filtrate was concentrated
in vacuo yielding colourless crystals of IV (0.41 g, 56%). 1H
NMR: d 0.04 (s, 9 H, SiMe3), 0.54 (s, 3 H, SiMe), 0.62 (s, 3
H, SiMe), 1.17 (t, 1H, J = 15.7 Hz, CH), 1.51 (t, 1H,
J = 14.3 Hz, CH); 7.03–7.17, 7.32–7.55, 7.82–7.87 (m,
Ph + C6H4); 13C{1H} NMR: d 0.32 (d, J = 2.9 Hz, SiMe3),
2.66 (d, J = 6.6 Hz, SiMe), 2.95 (d, J = 4.0 Hz, SiMe),
19.66 (d, J = 62.2 Hz, CH), 126.93 (d, J = 11.3 Hz), 128.26
Acknowledgements
We are grateful to Dr. P.G.N. Uiterweerd for supplying
single crystals of III and to the British Council and the Chi-
nese Government for financial support.
Appendix A. Supplementary data
Supplementary data associated with this article can be
found, in the online version, at doi:10.1016/j.jorganchem.
2006.02.011.
Table 5
Crystal data and refinements for complexes 3a, 6, III andIV
3a
6
III
IV
Formula
M
C
892.3
36H50N2P2PbSi4
C36H50N2P2Si4Sn
803.77
C19H30NPSi2
359.59
C18H26NPSi2
343.6
Temperature (K)
Crystal system
Space group
293(2)
293(2)
173(2)
293(2)
Monoclinic
P21/c (No. 14)
12.757(2)
10.763(4)
31.388(7)
96.85(2)
Monoclinic
P21/c (No. 14)
12.681(5)
10.705(2)
31.343(9)
96.66(2)
Monoclinic
P21/c (No. 14)
9.907(2)
22.965(6)
10.143(3)
111.36(2)
2149(1)
Tetragonal
I41/a (No. 88)
21.635(6)
21.635(6)
16.915(5)
90
˚
a (A)
˚
b (A)
˚
c (A)
b (°)
3
˚
U (A )
4279(2)
4226(2)
7917(4)
Z
4
4.16
4
0.82
4
0.24
16
0.26
l (Mo Ka) (mmꢀ1
)
Reflections collected
10714
7757
3993
2571
Independent reflections [R(int)
Reflections with I > 2r(I)
Final R indices [I > 2r(I)]
R indices (all data)
]
10282 [0.040]
4736
R1 0.060, wR2 0.098
R1 0.164, wR2 0.131
7413 [0.032]
4325
R1 0.054, wR20.133
R1 0.113, wR2 0.171
3769 [0.021]
3122
R1 0.041, wR20.100
R1 0.053, wR2 0.108
2412 [0.046]
1494
R1 0.066, wR20.140
R1 0.124, wR2 0.167

2756
P.B. Hitchcock et al. / Journal of Organometallic Chemistry 691 (2006) 2748–2756
(j) A. Steiner, S. Zacchini, P.I. Richards, Coordin. Chem. Rev. 227
(2002) 193.
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