Solution and solid state structural investigations of organotin(IV) compounds containing asymmetric imidodiphosphinato ligands. X-ray structures of R′′2Sn[(OPMe2)(OPPh2)N] 2 (R=Me, Bun, Ph)

Article abstract of DOI:10.1016/S0022-328X(01)01200-1

Organotin(IV) derivatives of the type R₂Sn[(OPMe₂)(OPPh₂)N]₂ (R=Me, Buⁿ, Bz, Ph) were prepared by metathesis reactions between R₂SnCl₂ and the potassium salt of the imidodiphosphinic acid, in toluene. Me₃SnCl and K[(OPMe₂)(OPPh₂)N] (1:1 molar ratio) in chloroform at room temperature gives Me₃Sn[(OPMe₂)(OPPh₂)N], while the NMR studies indicate that the corresponding triphenyltin(IV) derivative disproportionates gradually in solution to give Ph₂Sn[(OPMe₂)(OPPh₂)N]₂. Attempts to grow crystals of the trimethyltin(IV) derivative also gives Me₂Sn[(OPMe₂)(OPPh₂)N]₂ as a redistribution product. The compounds were characterized by IR and multinuclear NMR spectroscopy. The crystal and molecular structures of R₂Sn[(OPMe₂)(OPPh₂)N]₂ [R=Me (1), Buⁿ (2), Ph (4)] were established by X-ray diffractometry. The compounds exhibit similar spiro-bicyclic structures, with the tin atom as spiro atom and chelating ligands with the oxygen atoms of the similar OPR₂ groups in trans positions. The coordination geometry around the central metal atom is octahedral, with CSnC and OSnO (trans) angles of 180°. No significant differences were noted in the length of the tinoxygen, phosphorusoxygen and phosphorusnitrogen bonds, respectively, in relation to the different organic groups attached to tin or phosphorus atoms in a ligand moiety. The solution and solid state structures of the title compounds are discussed comparatively.

Full text of DOI:10.1016/S0022-328X(01)01200-1

Journal of Organometallic Chemistry 642 (2002) 71–79
www.elsevier.com/locate/jorganchem
Solution and solid state structural investigations of organotin(IV)
compounds containing asymmetric imidodiphosphinato ligands.
X-ray structures of R%%Sn[(OPMe2)(OPPh2)N]2 (R=Me, Bun, Ph)
2
Cristian Silvestru a,*, Roland Ro¨sler a, Anca Silvestru a, John E. Drake b,*
a Facultatea de Chimie, Uni6ersitatea Babes-Bolyai, R-3400 Cluj-Napoca, Romania
b Department of Chemistry and Biochemistry, Uni6ersity of Windsor, Windsor, Ontario, Canada N9B 3P4
Received 1 June 2001; accepted 30 August 2001
Abstract
Organotin(IV) derivatives of the type R2Sn[(OPMe2)(OPPh2)N]2 (R=Me, Bun, Bz, Ph) were prepared by metathesis reactions
between R2SnCl2 and the potassium salt of the imidodiphosphinic acid, in toluene. Me3SnCl and K[(OPMe2)(OPPh2)N] (1:1 molar
ratio) in chloroform at room temperature gives Me3Sn[(OPMe2)(OPPh2)N], while the NMR studies indicate that the correspond-
ing triphenyltin(IV) derivative disproportionates gradually in solution to give Ph2Sn[(OPMe2)(OPPh2)N]2. Attempts to grow
crystals of the trimethyltin(IV) derivative also gives Me2Sn[(OPMe2)(OPPh2)N]2 as a redistribution product. The compounds were
characterized by IR and multinuclear NMR spectroscopy. The crystal and molecular structures of R2Sn[(OPMe2)(OPPh2)N]2
[R=Me (1), Bun (2), Ph (4)] were established by X-ray diffractometry. The compounds exhibit similar spiro-bicyclic structures,
with the tin atom as spiro atom and chelating ligands with the oxygen atoms of the similar OPR2 groups in trans positions. The
coordination geometry around the central metal atom is octahedral, with CꢀSnꢀC and OꢀSnꢀO (trans) angles of 180°. No
significant differences were noted in the length of the tinꢀoxygen, phosphorusꢀoxygen and phosphorusꢀnitrogen bonds,
respectively, in relation to the different organic groups attached to tin or phosphorus atoms in a ligand moiety. The solution and
solid state structures of the title compounds are discussed comparatively. © 2002 Elsevier Science B.V. All rights reserved.
Keywords: Organotin(IV) compounds; Asymmetric imidodiphosphinato ligands
1. Introduction
Organotin(IV) derivatives of 1,1-dithiophosphorus
ligands (dithiophosphates, [(RO)2PS2]−, dithiophosphi-
nates, [R2PS2]−) have been the subject of numerous
structural studies [1–4] and it has often been suggested
that the restricted S···S bite distance plays an important
role in the distortion from ideal geometry around the
central tin atom. Structural studies on analogous
organotin(IV) complexes containing [R2PSO]− and
[R2PO2]− groups revealed a general tendency for asso-
ciation through bridging phosphorus ligands, i.e.
[Me3SnO2PPh2]4 [5], [Ph3SnO2P(OPh)2]6 [6], [R%Sn-
3
OSPR2]n (R%=R=Me, Ph) [7,8], [Me2Sn{O(S)-
PPh2}2]n [9], [R%Sn(O2PR2)2]n (R%=Et, Ph; R=Me,
2
Ph) [10,11].
* Corresponding authors. Fax: +40-64-190-818.
E-mail address: cristi@chem.ubbcluj.ro (C. Silvestru).
0022-328X/02/$ - see front matter © 2002 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(01)01200-1

72
C. Sil6estru et al. / Journal of Organometallic Chemistry 642 (2002) 71–79
In order to explore structural changes produced in
the absence of a restrictive ligand ‘bite’ we have studied
or spectroscopic proof on the formation of R4Sn, but
31P-NMR spectra are consistent with the conversion of
the Ph3Sn(IV) derivative into the Ph2Sn(IV) compound
4 (see below). Although the NMR data of a freshly
prepared sample of the trimethyltin(IV) complex 5 were
consistent with the presence of a SnC3 fragment, at-
tempts to grow single crystals suitable for X-ray diffrac-
tion studies led only to isolation of Me2Sn-
[(OPMe2)(OPPh2)N]2 (1).
organotin(IV) complexes containing ligands of general
formula [(XPR2)(YPR%)N]− (a), which exhibit a flexible
2
XPNPY skeleton.
We have previously reported that R2Sn[(XPPh2)-
(YPPh2)N]2 (X, Y=O, S) derivatives are monomeric,
with an almost perfect trans-C2SnX2Y2 octahedral core
(b) [12–16], while Me3Sn[(SPPh2)2N] exhibits a chain
polymeric structure (c) with the ligand acting as an
,
,
asymmetric bridge (SnꢀS 2.517 A, Sn···S 3.627 A) [15].
By comparison, interesting structural differences have
been reported for the related organotin(IV) derivatives
of b-diketones and thio analogs. Thus, Me2Sn-
[(OCMe)2CH]2 exhibits a similar perfect trans-C2SnO4
octahedral core (CꢀSnꢀC 180°) [17], in Me2Sn[(OCR)-
(SCR)CH]2 (R=Me, Ph) the C2Sn moiety is angular
(CꢀSnꢀC 139.4° for R=Me, and 134.2° for R=Ph) (d)
[18], while Ph3Sn[(OCPh)2CH] is monomeric with an
asymmetric monometallic biconnective ligand (e) [19].
To establish possible changes which might be pro-
duced by the presence of different organic groups at the
phosphorus atoms of the ligand unit, we have synthe-
sized and characterized RnSn[(OPMe2)(OPPh2)N]4−n
derivatives both in solution and the solid state. The
molecular structures of R2Sn[(OPMe2)(OPPh2)N]2 [R=
Me (1), Bun (2), Ph (4)] were established by X-ray
diffractometry.
2.2. IR studies
The strong infrared absorptions observed for all
organotin complexes in the regions 1250–1200 and
1120–1055 cm−1 were assigned to was(P2N) and w(PO)
stretching vibrations, respectively, by comparison with
the spectra of the free acid and its potassium salt, thus
suggesting bidentate coordination of the ligand unit
through both oxygen atoms. The SnCn stretching vibra-
tions could not be assigned in the case of alkyltin
derivatives, being obscured by strong absorption bands
of the phenyl rings and SnꢀO bonds.
2.3. NMR studies
All the diorganotin(IV) and Me3Sn[(OPMe2)-
(OPPh2)N] derivatives, as well as the free imidodiphos-
phinic acid and its potassium salt, were investigated by
solution NMR spectroscopy. Either the free acid and its
K salt or the organotin compounds displayed good
solubility in CDCl3 and their 1H and 13C spectra
showed the expected doublet pattern (due to phospho-
rus–proton and phosphorus–carbon couplings, respec-
tively) for the organic groups attached to phosphorus
atoms. For the R2Sn[(OPMe2)(OPPh2)N]2 [R=Me (1),
Bun (2), Bz (3)] and Me3Sn[(OPMe2)(OPPh2)N] (5)
complexes the spectra also contain characteristic reso-
nance signals for equivalent organic groups bonded to
tin. The coordination geometry of organotin(IV)
derivatives is reflected in the NMR parameters [20].
2. Results and discussion
2.1. Preparation
The title compounds were obtained as white crys-
talline solids by reacting the potassium salt of the
imidodiphosphinic acid with the appropriate organotin
chloride, in toluene or chloroform, according to Eq. (1):
RnSnCl4−n+(4−n)K[(OPMe2)(OPPh2)N]
2
1
“RnSn[(OPMe2)(OPPh2)N]4−n+(4−n)KCl
n=2 R=Me(1), Bun(2), Bz(3), Ph(4)
n=3 R=Me (5)
(1)
Thus, the values of the J(119SnC1H) and J(119Sn13C)
coupling constants fall in the region for six-coordinate
tin in the case of diorganotin derivatives [21]. Table 1
contains the calculated CꢀSnꢀC angles based on the
reported relationships between 2J(119SnC1H) and
1J(119Sn13C) coupling constants and the CꢀSnꢀC angle
[21–23]. In contrast with the monothio derivatives
R2Sn[(OPPh2)(SPPh2)N]2, the R2Sn[(OPMe2)(OPPh2)-
N]2 [R=Me (1), Bun (2)] compounds in solution dis-
play a CꢀSnꢀC angle close to 180° as was found in the
solid state (see below). The 119Sn resonances for the
diorganotin(IV) complexes appear as sharp signals and
their chemical shifts fall in the expected range for
six-coordinated tin [20].
The corresponding triphenyltin(IV) derivative could not
be isolated as a pure compound from the reaction
mixture, due to a quite fast redistribution process of the
expected product according to Eq. (2):
2R3Sn[(OPMe2)(OPPh2)N]
“R2Sn[(OPMe2)(OPPh2)N]2+R4Sn
(2)
A similar process has been previously noted for the
related R3Sn[(OPPh2)(SPPh2)N] (R=Me, Ph) [16] and
the (b-diketonato)triorganotin(IV) analogues [19]. No
attempts have been made so far to obtain any chemical
The 31P-NMR spectrum of (OPMe2)(OPPh2)NH ex-
hibits two singlet resonances at 44.7 (Me2PO) and 22.4

C. Sil6estru et al. / Journal of Organometallic Chemistry 642 (2002) 71–79
73
Table 1
angle in this case is about 120° and consistent with a
planar SnC3 moiety with bridging imidodiphosphinato
groups, a pattern observed in the solid state for the
dithio analogue, Me3Sn[(SPPh2)2N] [structure (c)] [15].
The NMR spectra of the diphenyltin(IV) derivative,
Ph2Sn[(OPMe2)(OPPh2)N]2 (4), deserve some special
comments. The 1H-NMR spectrum in the aromatic
region exhibits two doublet resonances for the ortho
protons of the phenyl groups attached to tin. On the
other hand, four singlets are observed in the 31P-NMR
spectrum of compound 4: 20.90, 21.74 (Ph2PO), 39.51,
39.63 ppm (Me2PO) (Fig. 1). This behavior suggests
nonequivalence of the phenyl groups attached to tin as
well as nonequivalence of the phosphorus atoms bear-
ing the same organic groups of the two ligand moieties,
respectively, in CDCl3 solution. Therefore a cis-C2SnO4
octahedral core with an angular CꢀSnꢀC fragment
might be proposed (structure f) for 4, which contrasts
with the trans-C2SnO4 cores suggested in solution for
the dialkyltin(IV) analogues 1–3. However, a trans-
C2SnO4 core with a linear CꢀSnꢀC fragment was estab-
lished in the solid state for 4 by single-crystal X-ray
diffraction (see below).
Correlations between 119SnC1H and 119Sn13C coupling constants (Hz)
and CꢀSnꢀC angles (q, °) in RnSn[(OPMe2)(SPPh2)N]4−n
Compound
1H
13C
2J(119SnC1H) CꢀSnꢀC 1J(119Sn13C) CꢀSnꢀC
Me2Sn[(OPMe2)- 120.0
(OPPh2)N]2 (1)
178 a
120 a
1188.0
1105.9
566.9
181 b
185 c
126 b
Bun2Sn[(OPMe2)-
(OPPh2)N]2 (2)
Me3Sn[(OPMe2)- 72.5
(OPPh2)N] (5)
a q=0.0105ꢀ Jꢀ −0.799ꢀ Jꢀ+122.4 [21].
2
2
2
b
c
1
ꢀ Jꢀ=11.4q−875 [22].
1
ꢀ Jꢀ=9.99q−746 [23].
ppm (Ph2PO), the splitting due to phosphorus–phos-
phorus coupling not being observed. The loss of the
acidic proton in the K salt is reflected in a significant
higher field (ca. 10–15 ppm) shift of the 31P resonance
signals [28.9 (Me2PO), 13.7 ppm (Ph2PO); the assign-
ment being based on the 1J(PC) coupling constants]
and the splitting due to phosphorus–phosphorus cou-
pling is observed [2J(PP) 7.8 Hz]. However, for the
dialkyltin(IV) derivatives 1–3 and Me3Sn[(OPMe2)-
(OPPh2)N] (5) the 2J(PP) is not resolved. The 31P
resonance assigned to Ph2PO (l=10.3 ppm) in the
spectrum of 5 is even more shifted to higher field
compared to the alkali metal starting material, suggest-
ing a primary coordination of the imidodiphosphinato
ligand through oxygen atom. The estimated CꢀSnꢀC
Fig. 1. 31P-NMR spectrum of Ph2Sn[(OPMe2)(OPPh2)N]2 (4).

74
C. Sil6estru et al. / Journal of Organometallic Chemistry 642 (2002) 71–79
Fig. 2. 31P-NMR spectrum of: (a) freshly prepared ‘Ph3Sn[(OPMe2)(OPPh2)N]’; and (b) 6-h old ‘Ph3Sn[(OPMe2)(OPPh2)N]’.
Alternatively, the presence of the two possible iso-
amount of the diphenyltin(IV) derivative 4 has already
formed. Indeed, the 31P spectrum of the same sample
recorded after 6 h (Fig. 2b) exhibits resonances of
increased intensity at 39.9, 22.0 and 21.2 ppm, consis-
tent with the conversion of the Ph3Sn[(OPMe2)(OPPh2)-
N] into the diphenyltin(IV) derivative 4 (cf. l 20.90,
mers (g) (OPMe2 trans OPMe2) and (h) (OPMe2 trans
OPPh2) for a diorganotin(IV) derivative containing a
linear C2Sn moiety, in a 1:1 molar ratio, might also
account for the observed NMR behavior of compound
4 in solution, if the interconversion between these forms
is frozen at room temperature:
In contrast to the trimethyltin(IV) derivative 5, the
triphenyltin(IV) analogue, Ph3Sn[(OPMe2)(OPPh2)N],
could not be obtained as a pure compound and at-
tempts to purify the solid product by recrystallization
from toluene, CH2Cl2 or MeCN, always resulted in
isolation of the Ph2Sn(IV) compound 4. To obtain
evidence for the redistribution process, a mixture of
stoichiometric amounts of pure Ph3SnCl and
K[(OPMe2)(OPPh2)N] was placed in an NMR tube and
the reaction followed by 31P-NMR spectroscopy. The
spectrum of the fresh sample (Fig. 2a) exhibited two
main broad resonances at 6.9 and 24.7 ppm for the
triphenylltin(IV) derivative 5, which were assigned to
Ph2PO and Me2PO phosphorus atoms, respectively. In
addition, the spectrum also contains resonances of low
intensity (l ca. 21 and 40 ppm) indicating that a small
21.74 (Ph2PO), 39.51, 39.63 ppm (Me2PO) for pure
Ph2Sn[(OPMe2)(OPPh2)N]2).
2.4. Crystal and molecular structure of R2Sn[(OPMe2)-
(OPPh2)N]2 [R=Me (1), Bun (2), Ph (4)]
The solid state structures of R2Sn[(OPMe2)(OPPh2)-
N]2, R=Me (1), Bun (2), Ph (4), were determined by
single-crystal X-ray diffraction. Selected bond distances
and angles are listed in Table 2. Figs. 3–5 show the
ORTEP-like view of the molecular structures of 1, 2 and
4, with the atom numbering scheme. For all three
compounds the crystal contains discrete molecular
units, separated by normal van der Waals distances.
The molecular structures are very similar regardless

C. Sil6estru et al. / Journal of Organometallic Chemistry 642 (2002) 71–79
75
of the nature of the organic groups attached to tin and
therefore a general description for these compounds is
given.
The central tin atom occupies a center of inversion.
The SnC2 unit is linear [C(1)ꢀSn(1)ꢀC(1%) 180°]. The
phenyl groups on tin in 4 are coplanar and their
orientation is almost orthogonal to the N(1)···N(1)% axis
(173.6°). The two asymmetric ligand moieties are
monometallic biconnective, thus resulting in a distorted
octahedral coordination around tin, with the carbon
atoms of the organic groups attached to tin in axial
positions. The equatorial SnO4 system is planar, with
the trans positions occupied by oxygen atoms attached
to phosphorus atoms bearing the same organic groups
[O(1)ꢀSn(1)ꢀO(1)% and O(2)ꢀSn(1)ꢀO(2)% angles of 180°].
Thus, of two possible isomers (g) (OPMe2 trans
OPMe2) and (h) (OPMe2 trans OPPh2), only isomer (g)
is observed.
The distortion of the coordination octahedron is due
to the very small differences between the endocyclic and
Fig. 3. ORTEP plot of the molecule Me2Sn[(OPMe2)(OPPh2)N]2 (1).
The atoms are drawn with 30% probability ellipsoids. Hydrogen
atoms are excluded for clarity.
Table 2
,
Relevant interatomic distances (A) and angles (°) in
Me2Sn[(OPMe2)(OPPh2)N]2 (1), Bun2Sn[(OPMe2)(OPPh2)N]2 (2) and
Ph2Sn[(OPMe2)(OPPh2)N]2 (4)
1
2
4
Interatomic distances
Sn(1)ꢀC(1)
Sn(1)ꢀO(1)
Sn(1)ꢀO(2)
P(1)ꢀO(1)
P(1)ꢀN(1)
P(2)ꢀO(2)
P(2)ꢀN(1)
O(1)···O(2)
O(1)···O(2%)
2.090(4)
2.210(3)
2.219(3)
1.515(3)
1.590(3)
1.517(3)
1.592(3)
3.146(3)
3.118(4)
2.127(8)
2.217(5)
2.214(5)
1.507(5)
1.583(6)
1.518(4)
1.578(6)
3.109(6)
3.158(6)
2.128(18)
2.156(12)
2.184(11)
1.531(13)
1.554(15)
1.513(11)
1.555(14)
3.11(2)
3.04(1)
Bond angles
O(1)ꢀSn(1)ꢀO(2)
O(1)ꢀSn(1)ꢀO(2)%
O(1)ꢀSn(1)ꢀO(1)%
O(2)ꢀSn(1)ꢀO(2)%
O(2)ꢀSn(1)ꢀO(1)%
O(2%)ꢀSn(1)ꢀO(1%)
90.51(10)
89.49(10)
180.00
180.00
89.49(10)
90.51(10)
89.11(16)
90.89(16)
180.00
180.00
90.89(16)
89.11(16)
91.2(4)
88.8(4)
180.00
180.00
88.8(4)
91.2(4)
Fig. 4. ORTEP plot of the molecule Bu2Sn[(OPMe2)(OPPh2)N]2 (2).
The atoms are drawn with 30% probability ellipsoids. Hydrogen
atoms are excluded for clarity.
C(1)ꢀSn(1)ꢀC(1%)
180.00
180.00
180.00
C(1)ꢀSn(1)ꢀO(1)
C(1)ꢀSn(1)ꢀO(2)
C(1)ꢀSn(1)ꢀO(1%)
C(1)ꢀSn(1)ꢀO(2%)
C(1%)ꢀSn(1)ꢀO(1)
C(1%)ꢀSn(1)ꢀO(2)
C(1%)ꢀSn(1)ꢀO(1%)
C(1%)ꢀSn(1)ꢀO(2%)
89.71(16)
91.11(14)
90.29(16)
88.89(14)
90.29(16)
88.89(14)
89.71(16)
91.11(14)
88.8(3)
91.4(2)
91.2(3)
88.6(2)
91.2(3)
88.6(2)
88.8(3)
91.4(2)
89.6(6)
89.6(6)
90.4(6)
90.4(6)
90.4(6)
90.4(6)
89.6(6)
89.6(6)
exocyclic OꢀSnꢀO angles (Table 2), and the slight devi-
ation of the CꢀSnꢀC axis from orthogonality to the
equatorial plane [CꢀSnꢀO range: 88.8–91.4°]. The
SnꢀO bond lengths within a molecule of a 1, 2 and 4
are equivalent regardless of the nature of the organic
groups attached to phosphorus atoms; they are of the
same magnitude as observed in related analogues con-
Sn(1)ꢀO(1)ꢀP(1)
O(1)ꢀP(1)ꢀN(1)
P(1)ꢀN(1)ꢀP(2)
O(2)ꢀP(2)ꢀN(1)
Sn(1)ꢀO(2)ꢀP(2)
128.63(15)
115.64(16)
124.8(2)
116.78(15)
127.93(14)
130.9(3)
116.0(3)
130.0(4)
117.6(3)
129.2(3)
129.5(6)
114.4(7)
135.7(9)
115.0(7)
126.8(7)
taining symmetric or asymmetric ligand units:
n
,
Bu2Sn[(OPPh2)2N]2, average SnꢀO 2.203(1) A [14];
R2Sn[(OPPh2)(SPPh2)N]2 (R=Me, Ph), average
,
Symmetry equivalent position (−x, −y, −z) given by a prime.
2.194(6) A [16].

76
C. Sil6estru et al. / Journal of Organometallic Chemistry 642 (2002) 71–79
In the coordinated ligand, the PꢀO [range: 1.507(5)–
account for the differences observed in the SnO2P2N
ring conformation.
,
1.531(13) A] bonds are of the same magnitude as the
single phosphorusꢀoxygen bond in Ph2P(ꢁO)OH [PꢀO
,
1.526(6), PꢁO 1.486(6) A] [24]. Within a ligand unit the
phosphorusꢀnitrogen bonds, regardless the nature of
the organic groups attached to phosphorus atoms, are
again equivalent within experimental errors and their
3. Experimental
3.1. Materials and procedures
,
magnitude [range 1.554(15)–1.592(3) A] suggests con-
siderable double bond character [cf. [(Me3Si)2Nꢀ
Bz2SnCl2 was prepared from benzyl chloride and Sn
powder [26], while the other organotin chlorides were
commercial products. Solvents were dried and freshly
distilled prior to use. Infrared spectra were run in the
range 4000–200 cm−1 as KBr pellets on a Perkin–
t
,
P(ꢁNBu )S]2: PꢀN 1.662(2), PꢁN 1.529(2) A)] [25].
The bidentate nature of the imidodiphosphinato lig-
and units within a R2Sn[(OPMe2)(OPPh2)N]2 molecule
leads to an inorganic bicyclic system, NP2O2SnO2P2N,
with the metal as spiro atom. Although some delocal-
ization of the p-electrons over the OPNPO systems is
suggested by the magnitude of the bonds, the six-mem-
bered SnO2P2N rings are not planar but exhibit vari-
able conformations close to planarity. Thus a chair
conformation was found in 2 [the metal and N(1) atoms
in the apices; deviations from the O2SnO2 plane: P(1)
1
Elmer 283B instrument. The H-, 13C-, 31P- and 119Sn-
NMR spectra were recorded as CDCl3 or CD3OD (for
the K salt) solutions using VARIAN VXR 300S or
GEMINI 300 instruments, operating at 299.5, 75.4,
121.4 and 111.9 MHz, respectively. The chemical shifts
are reported in ppm relative to TMS, H3PO4 85%, and
Me4Sn, respectively. Abbreviations used in multiplic-
ities are: s, singlet; d, doublet; dd, doublet of doublets;
ddd, doublet of doublet of doublets; t, triplet; tq, triplet
of quartets; m, multiplet.
,
−0.116, P(2) −0.188, N(1) 0.000 A], while in 1 and 4
the SnO2P2N rings exhibit boat conformation of vari-
able distortion and with different atom types in the
apices; the metal and N(1) atoms in 1 [almost planar
SnO2P2 system; deviations from the O2SnO2 plane: P(1)
0.254, P(2) 0.251, N(1) 0.063 A], and P(2) and O(1)
atoms in 4 [deviations from the O2SnO2 plane: P(1)
3.2. Preparation of P,P-dimethyl-P%,P%-diphenylimido-
diphosphinic acid, (OPMe2)(OPPh2)NH
,
,
0.163, P(2) −0.394, N(1) −0.121 A]. For all three
The compound was prepared as described previously
[27]. m.p. 225 °C (lit. [27]: 217 °C). Anal. Found: C,
57.26; H, 5.89; N, 4.68. Calc. for C14H17NP2O2: C,
57.33; H, 5.85; N, 4.77%. IR (cm−1): 1170s, 1155vs,
1130m [w(PO)], 925s [was(P2NH)]. 1H-NMR: l 1.52d
[6H, PꢀCH3, 2J(PH) 14.2 Hz], 7.44m (6H, PꢀC6H5-
compounds the OꢀSnꢀO, SnꢀOꢀP and OꢀPꢀN angles
are quite similar (Table 2), but the P(1)ꢀN(1)ꢀP(2)
angles exhibit significant differences: 124.8(2)° for 1,
130.0(4)° for 2, and 135.7(9)° for 4. The O(1)···O(2) bite
,
in the ligand unit are also different, i.e. 3.146 A for 1,
3.109 A for 2, and 3.11 A for 4, thus supporting the
high flexibility of the OPNPO skeleton which might
3
,
,
meta+para), 7.83dd [4H, PꢀC6H5-ortho, J(PH) 12.8,
1
3J(HH) 7.0 Hz]. 13C-NMR: l 19.54d [PꢀCH3, J(PC)
Fig. 5. ORTEP plot of the molecule Ph2Sn[(OPMe2)(OPPh2)N]2 (4). The atoms are drawn with 30% probability ellipsoids. Hydrogen atoms are
excluded for clarity.

C. Sil6estru et al. / Journal of Organometallic Chemistry 642 (2002) 71–79
77
3
85.8 Hz], 128.41d [Cm, J(PC) 13.9 Hz], 131.24d [Co,
2J(PC) 10.4 Hz], 131.94s (Cp), 133.67d [Ci, 1J(PC) 126.4
Hz]. 31P-NMR: l 22.4s [Ph2PO, 1J(PC) 126.3 Hz]; 44.7s
(Me2PO).
3.5. Preparation of bis(P,P-dimethyl-P%,P%-diphenyl-
imidodiphosphinato)dibutyltin(IV), Bun2Sn[(OPMe2)-
(OPPh2)N]2 (2)
Prepared as above from Bun2SnCl2 (0.304 g, 1 mmol)
and K[(OPMe2)(OPPh2)N] (0.662 g, 2 mmol) and re-
crystallized from methanol. Yield: 0.67 g (82%, after
recrystallization), m.p. 197–9 °C. Anal. Found: C,
52.7; H, 6.3; N, 3.2; Calc. For C36H50N2O4P4Sn: C,
52.9; H, 6.2; N, 3.4%. IR (cm−1): 1225vs, br [was(P2N)],
3.3. Preparation of potassium P,P-dimethyl-P%,P%-
diphenylimidodiphosphinate, K[(OPMe2)(OPPh2)N]
A mixture of (OPMe2)(OPPh2)NH (9.82 g, 33.5
mmol) and KOBut (3.76 g, 33.5 mmol) in 250 ml
anhydrous diethyl ether was stirred for 3 days. The
solid product was filtered off, washed with anhydrous
benzene, dried at 120 °C, and then extracted several
times with acetonitrile in a Soxhlet apparatus. After
removal of the organic solvent in a rotary evaporator,
the title compound was isolated as fine, white crystals,
which are very hygroscopic and deliquescent. Yield:
9.64 g (87%), m.p. 264–269 °C. IR (cm−1): 1230vs, br
1
1120ms, 1080s, 1060vs [w(PO)]. H-NMR: l 0.57t [6H,
Snꢀ(CH2)3CH3, 3J(HH) 7.3 Hz], 1.00tq [4H,
Snꢀ(CH2)2CH2CH3, 3J(HH) 7.1 Hz], 1.43m [8H,
2
Snꢀ(CH2)2CH2CH3], 1.49d [12H, PꢀCH3, J(PH) 14.0
Hz], 7.37m (12H, PꢀC6H5-meta+para), 7.81ddd [8H,
PꢀC6H5-ortho, 3J(PH) 12.4, 3J(HH) 7.7, 4J(HH) 1.9
1
Hz]. 13C-NMR: l 13.62s (Cd), 20.52d [PꢀCH3, J(PC)
95.0 Hz], 26.44s [C?, 3J(119/117SnC) 174.8 Hz], 28.38s
[Cg, 2J(119/117SnC) 43.5 Hz], 38.09s [Ca, 1J(119SnC)
1105.9, 1J(117SnC) 1057.3 Hz], 127.88d [Cm, 3J(PC) 13.7
Hz], 130.46s (Cp), 131.17d [Co, 2J(PC) 10.3 Hz],
137.70d [Ci, 1J(PC) 136.2 Hz]. 31P-NMR: l 18.1s
(Ph2PO), 36.6s (Me2PO). 119Sn-NMR: l−434.0s.
1
[was(P2N)], 1170s, 1155vs, 1130 m [w(PO)]. H-NMR: l
1.30d [6H, PꢀCH3, 2J(PH) 11.1 Hz], 7.36m (6H,
PꢀC6H5-meta+para), 7.83ddd [4H, PꢀC6H5-ortho,
3J(PH) 12.0, J(HH) 6.5, J(HH) 2.1 Hz]. 13C-NMR: l
3
4
1
3
20.64dd [PꢀCH3, J(PC) 90.5, J(PC) 3.5 Hz], 128.74d
3.6. Preparation of bis(P,P-dimethyl-P%,P%-diphenyl-
imidodiphosphinato)dibenzyltin(IV), Bz2Sn[(OPMe2)-
(OPPh2)N]2 (3)
3
2
[Cm, J(PC) 11.6 Hz], 131.02s (Cp), 132.44d [Co, J(PC)
1
3
10.4 Hz], 140.71dd [Ci, J(PC) 131.7, J(PC) 5.2 Hz].
31P-NMR: l 13.7d [Ph2PO, J(PP) 7.8, J(PC) 132.1
2
1
2
1
Hz], 28.9d [Me2PO, J(PP) 7.8, J(PC) 89.7 Hz].
Prepared as above from Bz2SnCl2 (0.372 g, 1 mmol)
and K[(OPMe2)(OPPh2)N] (0.662 g, 2 mmol). The in-
soluble product was filtered, and then extracted with
toluene in a Soxhlet apparatus for 24 h (very low
solubility in toluene). Yield: 0.49 g (55%, after extrac-
tion), m.p. 269–271 °C. Anal. Found: C, 56.7; H, 4.8;
N, 3.2; Calc. for C42H46N2O4P4Sn: C, 57.0; H, 5.2; N,
3.2%. IR (cm−1): 1250vs, br [was(P2N)], 1115m, 1075vs,
1060vs [w(PO)]. 1H-NMR: l 1.03d [12H, PꢀCH3,
3.4. Preparation of bis(P,P-dimethyl-P%,P%-diphenyl-
imidodiphosphinato)dimethyltin(IV), Me2Sn[(OPMe2)-
(OPPh2)N]2 (1)
A mixture of Me2SnCl2 (0.292 g, 1.33 mmol) and
K[(OPMe2)(OPPh2)N] (0.883 g, 2.66 mmol) in 20 ml
anhydrous toluene was stirred under reflux for 2 h, then
filtered hot to remove the resulting KCl. On cooling
and partial evaporation of the solvent colorless crystals
started to deposit. The solid product was separated by
filtration and recrystallized from methanol. Yield: 0.73
g (75%, after recrystallization), m.p. 232–234 °C. Anal.
Found: C, 48.8; H, 4.8; N, 3.6; Calc. for
C30H38N2O4P4Sn: C, 49.1; H, 5.2; N, 3.8%. IR (cm−1):
2
2J(PH) 14.1 Hz], 2.79s [4H, SnꢀCH2C6H5, J(119SnH)
155.3, 2J(117SnH) 149.9 Hz], 6.72s, br (4H,
SnꢀCH2C6H5-ortho), 6.79s, br (6H, SnꢀCH2C6H5-
meta+para), 7.36m (12H, PꢀC6H5-meta+para),
3
3
7.82ddd [8H, PꢀC6H5-ortho, J(PH) 12.6, J(HH) 7.5,
4J(HH) 2.1 Hz]. 13C-NMR: l 19.89d [PꢀCH3, J(PC)
1
96.1 Hz], 46.03s (SnꢀCH2C6H5, 1J(119/117SnC) 1077.4
Hz) 123.84s (Cp, SnꢀCH2C6H5), 127.60s (Cm,
3
SnꢀCH2C6H5), 128.07d [Cm, PꢀC6H5, J(PC) 12.6 Hz],
1
129.49s [Co, SnꢀCH2C6H5, J(119SnC) 59.6, J(117SnC)
47.1 Hz], 130.65s (Cp, PꢀC6H5), 131.25d [Co, PꢀC6H5,
2J(PC) 10.2 Hz], 137.69d [Ci, PꢀC6H5, 1J(PC) 137.6
Hz], 141.10s (Ci, SnꢀCH2C6H5). 31P-NMR: l 17.8s
(Ph2PO), 38.5s (Me2PO). 119Sn-NMR: l−512.0s.
3
3
1200vs,br [was(P2N)], 1120s, 1080vs, 1060vs [w(PO)]. H-
NMR:
l
0.86s [6H, SnꢀCH3, 2J(119SnH) 120.0,
2J(117SnH) 115.5 Hz], 1.42dd [12H, PꢀCH3, 2J(PH)
14.1, 4J(PH) 1.2 Hz], 7.35 m (12H, PꢀC6H5-meta+
para), 7.78ddd [8H, PꢀC6H5-ortho, 3J(PH) 12.8,
3J(HH) 7.5, J(HH) 1.8 Hz]. 13C-NMR: l 20.19s [Sn-
4
1
1
CH3, J(119SnC) 1188.0, J(117SnC) 1136.2 Hz], 20.63dd
3.7. Preparation of bis(P,P-dimethyl-P%,P%-diphenylimi-
dodiphosphinato)diphenyltin(IV),
Ph2Sn[(OPMe2)(OPPh2)N]2 (4)
[P-CH3, 1J(PC) 95.9, 3J(PC) 2.3 Hz], 128.00d [Cm,
3J(PC) 12.9 Hz], 130.63s (Cp); 131.18d [Co, J(PC) 10.3
2
Hz], 137.49d [Ci, J(PC) 135.0 Hz]. 31P-NMR: l 18.8s
1
(Ph2PO), 37.2s (Me2PO). 119Sn-NMR: l −411.7s.
Prepared as above from Ph2SnCl2 (0.344 g, 1 mmol)

78
C. Sil6estru et al. / Journal of Organometallic Chemistry 642 (2002) 71–79
and K[(OPMe2)(OPPh2)N] (0.662 g, 2 mmol) and re-
crystallized from toluene. Yield: 0.72 g (84%, after
recrystallization), m.p. 235–237 °C. Anal. Found: C,
55.7; H, 4.8; N, 3.2; Calc. for C40H42N2O4P4Sn: C, 56.0;
H, 4.90; N, 3.3%. IR (cm−1): 1230vs,br [was(P2N)],
1115m, 1075vs, 1055vs [w(PO)]. 1H-NMR: l 1.23d
3.8. Preparation of (P,P-dimethyl-P%,P%-diphenyl-
imidodiphosphinato)trimethyltin(IV), Me3Sn[(OPMe2)-
(OPPh2)N] (5)
A mixture of Me3SnCl (0.2 g, 1 mmol) and
K[(OPMe2)(OPPh2)N] (0.331 g, 1 mmol) in 25 ml chlo-
roform were stirred for 2 h at room temperature. The
resulting KCl was filtered off and the solvent removed
in vacuum to dryness. The white, solid product thus
obtained was solved in CH2Cl2 and re-precipitated by
slow addition of hexane to result in colorless microcrys-
talline Me3Sn[(OPMe2)(OPPh2)N]. Yield: 0.35 g (77%),
m.p. 139–142 °C. Anal. Found: C, 44.5; H, 5.8; N, 3.2;
Calc. for C17H25NO2P2Sn: C, 44.8; H, 5.5; N, 3.1%. IR
(cm−1): 1230vs, br [was(P2N)], 1200s, 1125vs, 1110vs
[w(PO)]. 1H-NMR: l 0.45s [9H, Sn-CH3, 2J(119SnH)
2
[12H, PꢀCH3, J(PH) 14.3 Hz], 7.12m (complex signal)
(14H, SnꢀC6H5-para, PꢀC6H5-meta+para), 7.39m
(complex signal) (12H, SnꢀC6H5-meta, PꢀC6H5-ortho),
3
2
7.91d [2H, SnꢀC6H5-ortho, J(HH) 7.5, J(119/117SnH)
115.7 Hz], 7.94d [2H, SnꢀC6H5-ortho, 3J(HH) 7.7,
2J(119/117SnH) 113.9 Hz]. 13C-NMR: l 20.10d [PꢀCH3,
1J(PC) 95.9 Hz], 126.90s, 126.97s (Cm, SnC6H5),
3
127.30s (Cp, SnꢀC6H5), 127.57d [Cm, PꢀC6H5, J(PC)
13.7 Hz], 130.36s (Cp, PꢀC6H5), 131.33m [Co, PꢀC6H5],
3
135.30s [Co, SnꢀC6H5, J(119/117SnC) 68.5 Hz], 136.19d
1
2
2
[Ci, PꢀC6H5, J(PC) 134.1 Hz], 136.52d [Ci, PꢀC6H5,
72.5, J(117SnH) 70.9 Hz], 1.24d [6H, PꢀCH3, J(PH)
1J(PC) 137.1 Hz], 156.03s (Ci, SnꢀC6H5). 31P-NMR: l
13.5 Hz], 7.34m (6H, PꢀC6H5-meta+para), 7.71ddd
2
3
3
4
20.90s [Ph2PO, J(119/117SnP) 55.9 Hz], 21.74s [Ph2PO,
[4H, PꢀC6H5-ortho, J(PH) 12.5, J(HH) 7.8, J(HH)
2J(119/117SnP) 52.3 Hz], 39.51s (Me2PO), 39.63s
(Me2PO).
2.1 Hz]. 13C-NMR: l 2.76s [SnꢀCH3, J(119SnC) 566.9,
1
2J(117SnH) 542.3 Hz]; 20.66dd [PꢀCH3, 1J(PC) 93.6,
Table 3
X-ray crystal data and structure refinement for (1), (2) and (4)
Parameter
1
2
4
Empirical formula
Formula weight
Temperature (K)
C
30H38N2O4P4Sn
C36H50N2O4P4Sn
817.35
299(2)
0.71069
Monoclinic
P21/c
C40H42N2O4P4Sn
857.33
299(2)
0.71069
Triclinic
P1
733.19
299(2)
0.71069
Triclinic
P1
,
Wavelength (A)
Crystal system
Space group
Unit cell dimensions
,
a (A)
10.473(5)
10.794(5)
8.875(4)
107.15(4)
90.56(4)
12.365(9)
7.969(6)
20.306(9)
90.00
10.912(6)
11.045(5)
9.659(5)
104.36(5)
91.93(5)
,
b (A)
,
c (A)
h (°)
i (°)
102.16(6)
k (°)
116.85(3)
843.3(7)
1
1.444
0.983
90.00
1956(2)
2
1.388
0.855
844
116.54(5)
994.8(9)
1
1.431
0.845
−3
,
V (A
)
Z
Dcalc (g cm−3
)
Absorption coefficient (mm−1
F(000)
)
374
438
Crystal size (mm)
q range for data collection (°)
Reflections collected
0.30×0.25×0.22
2.21–25.00
3159
0.32×0.28×0.26
1.68–24.99
3605
0.25×0.20×0.20
2.12–25.00
3694
Independent reflections
2980 [Rint=0.0495]
0.8128 and 0.7570
2980/0/188
1.032
3433 [Rint=0.1184]
0.8082 and 0.7715
3433/0/215
1.033
3493 [Rint=0.1289]
0.8492 and 0.8165
3493/6/220
1.051
R1=0.0902,
wR2=0.2459
R1=0.2362,
wR2=0.3242
0.007(3)
Max and min transmissions
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [F2\4|(F2)]
R1=0.0306, wR2=0.0720
R1=0.0401, wR2=0.0931
R indices (all data)
R1=0.0510, wR2=0.0796
R1=0.1284, wR2=0.1213
Extinction coefficient
Largest difference peak and hole (e A
0.0013(9)
0.423 and −0.743
0.0019(3)
0.570 and −0.575
−3
,
)
2.072 and −0.940

C. Sil6estru et al. / Journal of Organometallic Chemistry 642 (2002) 71–79
79
3
3J(PC) 3.0 Hz], 127.76d [Cm, J(PC) 12.8 Hz]; 130.08s
(Cp), 131.42d [Co, 2J(PC) 10.2 Hz], 138.38dd [Ci,
1J(PC) 135.3, 3J(PC) 4.5 Hz]. 31P-NMR: l 8.2s
Code 177). One of us (J.E.D.) wishes to thank the
Natural Sciences and Engineering Research Council of
Canada for financial support.
1
(Ph2PO, J(PC) 134.7 Hz); 24.3s (Me2PO).
3.9. X-ray structure determination
References
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Pergamon Press, Oxford, 1982, pp. 529–530.
Colourless block crystals of Me2Sn[(OPMe2)-
(OPPh2)N]2 (1), Bu2nSn[(OPMe2)(OPPh2)N]2 (2), and
Ph2Sn[(OPMe2)(OPPh2)N]2 (4), were mounted on glass
fibers and sealed with epoxy glue. Data were collected
on a Rigaku AFC6 diffractometer with graphite-
monochromated Mo–Ka radiation, operating at 50 kV
and 35 mA. Data collection and cell refinement [28]
gave cell constants corresponded to triclinic (for 1 and
4) and monoclinic (for 2) cells whose dimensions are
given in Table 3 along with other experimental parame-
ters. An absorption correction was applied [29] which
resulted in transmission factors ranging from 0.8128 to
0.7570 for 1, 0.8082 to 0.7715 for 2, and 0.8492 to
0.8165 for 4.
The structures were solved by direct methods [30],
and the structures were refined using the WINGX version
[31] of SHELX-97 [32]. All of the non-hydrogen atoms
were treated anisotropically and the hydrogen atoms
were included in idealized positions with isotropic ther-
mal parameters set at 1.2 times that of the carbon atom
to which they were attached. The final cycle of full-ma-
trix least-squares refinement [32] was based on 2980 for
1, 3433 for 2, and 3493 for 4 observed reflections [2390
for 1, 1866 for 2, and 1546 for 4 for F2\4s(F2)] and
188 for 1, 215 for 2, and 220 for 4 variable parameters
and converged (largest parameter shift was 0.001 times
its esd).
[21] T.P. Lockhart, W.F. Manders, Inorg. Chem. 25 (1986) 892.
[22] T.P. Lockhart, W.F. Manders, J.J. Zuckerman, J. Am. Chem.
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4. Supplementary material
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C.W. Carter Jr., R.M. Sweet (Eds.), Macromolecular Crystallog-
raphy, Part A, vol. 276, Academic Press, New York, 1997, p.
307.
Crystallographic data for the structural analysis of
compounds 1, 2 and 4 have been deposited with the
Cambridge Crystallographic Data Centre [CCDC no.
162460 (1), 162461 (2), 162462 (4)]. Copies of this
information may be obtained free of charge from The
Director, CCDC, 12 Union Road, Cambridge CB2
1EZ, UK (Fax: +44-1223-336033; e-mail: deposit@
ccdc.cam.ac.uk or www: http://www.ccdc.cam.ac.uk).
[29] SORTAV: (a) R.H. Blessing, Acta Crystallogr. Sect. A 51 (1995)
33;
Acknowledgements
(b) R.H. Blessing, J. Appl. Cryst. 30 (1997) 421.
[30] G.M. Sheldrick, Acta Crystallogr., Sect. A 46 (1990) 467.
[31] L.J. Farrugia, J. Appl. Cryst. 32 (1999) 837.
[32] G.M. Sheldrick, SHELXL-97, University of Go¨ttingen, Germany,
1997.
This work was supported by the Romanian National
Council for High Education Scientific Research
through research project No. 46174/1997 (CNCSIS