Scandium halide complexes of phosphine- and arsine-oxides: Synthesis, structures and 45Sc NMR studies

Article abstract of DOI:10.1016/S0277-5387(02)01016-1

The reactions of SCCl₃·6H₂O, ScBr₃·6H₂O and SCI₃·8H₂O with Ph₃PO, Ph₃AsO, Ph₂MePO, Me₃PO and Me₃AsO have been examined in EtOH or Me

Full text of DOI:10.1016/S0277-5387(02)01016-1

Polyhedron 21 (2002) 1579Á1588
/
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Scandium halide complexes of phosphine- and arsine-oxides:
45
synthesis, structures and Sc NMR studies
Nicholas J. Hill, William Levason *, Michael C. Popham, Gillian Reid,
Michael Webster
Department of Chemistry, University of Southampton, Southampton SO17 1BJ, UK
Received 31 October 2001; accepted 20 February 2002
Abstract
The reactions of ScCl3×
examined in EtOH or Me2CO solution. The new complexes [ScCl(Me3PO)5]Cl2, [Sc(Me3PO)6]X3 (Xꢀ
(XꢀCl, Br or I), [ScX2(Ph3AsO)4]X, [Sc(Me3AsO)6]X3 (XꢀCl, Br or I), [ScCl3(Ph2MePO)3] and [ScBr2(Ph2MePO)4]Br were
isolated as solids and were characterised by analysis, IR and multinuclear (1H, 31P{1H} and 45Sc) NMR spectroscopy and
1/2Et2O, [ScCl2(Ph3AsO)4]Cl and [Sc(Me3AsO)6]Br3 are
/
6H2O, ScBr3×
/
6H2O and ScI3×
/
8H2O with Ph3PO, Ph3AsO, Ph2MePO, Me3PO and Me3AsO have been
/Br or I), [ScX2(Ph3PO)4]X
/
/
conductance measurements. The crystal structures of [ScBr2(Ph3PO)4]Br×
/
also reported. The solution speciation (in CH2Cl2 or MeNO2) in the various systems was examined by multinuclear NMR
spectroscopy. The 45Sc NMR chemical shifts and line widths show systematic trends with donor set and symmetry, which are
described. No reaction between these ligands and ScF3×/1/2H2O was observed. # 2002 Elsevier Science Ltd. All rights reserved.
Keywords: Scandium; Phosphine oxide; Arsine oxide; X-ray structures; 45Sc NMR
1. Introduction
these complexes the coordinated nitrate groups are
bidentate, so quite different behaviour is to be expected
with the monoatomic halide ligands. We have also
reported [9] studies of yttrium halide complexes of these
ligands, all of which are six-coordinate [YX2(Ph3PO)4]Z
The chemistry of scandium is the least studied of any
3d element, although interest in its complexes has
increased in recent years with applications for example,
in a-olefin polymerisation catalysis [1,2], various organic
(Xꢀ
/
Cl, Br or I; ZꢀX or PF6), [YX3(Ph2MePO)3],
/
[YCl2(Ph2MePO)4]PF6, [YCl(Ph3PO)5][SbCl6]2, [Y(Me3-
PO)6]X3, [YX2(Ph3AsO)4]X and [Y(Me3AsO)6]Cl3. No
complexes of scandium halides with pnictogen oxide
ligands have been described, and hence we have now
carried out systematic studies of the reactions of
functional group transformations [3,4], and solÁ
preparations for oxide materials [5]. The quadrupolar
45Sc nucleus (45Scꢀ
100%, Iꢀ7/2, Q (quadrupole
moment)ꢀ 0.22ꢂ
10ꢁ28 m), which is one of the
most sensitive NMR nuclei (Dcꢀ1700) has been little
/
gel
/
/
/
ꢁ
/
/
/
scandium halides ScX3×
/
nH2O (XꢀF, Cl, Br or I) with
/
used [6] but potentially should provide a very suitable
probe for studying solution speciation. We have re-
ported [7,8] detailed studies of Sc(NO3)3 and Y(NO3)3
complexes with R3PO and R3AsO ligands which exhibit
a range of stoichiometries including nine-coordinate
Ph3PO, Ph3AsO, Me3PO, Ph2MePO and Me3AsO.
2. Results and discussion
[Y(R3PO)3(NO3)3],
(NO3)2]ꢃ (Mꢀ
Sc or Y) and [Sc(Ph3PO)2(NO3)3], and
six-coordinate [M(Me3AsO)6]3ꢃ (Mꢀ
Sc or Y). In all
eight-coordinate
[M(R3PO)4-
2.1. Synthesis
/
/
Reactions of the hydrated scandium halides (exclud-
ing fluoride) with Ph3PO, Ph3AsO, Ph2MePO, Me3PO
and Me3AsO in ethanol or acetone were carried out
using a variety of molar ratios and reaction conditions.
Pure solids could be isolated as described in the Section
* Corresponding author. Tel.: ꢃ
593-781
E-mail address: wxl@southampton.ac.uk (W. Levason).
/
44-2380-595-000; fax: ꢃ44-2380-
/
0277-5387/02/$ - see front matter # 2002 Elsevier Science Ltd. All rights reserved.
PII: S 0 2 7 7 - 5 3 8 7 ( 0 2 ) 0 1 0 1 6 - 1

1580
N.J. Hill et al. / Polyhedron 21 (2002) 1579Á1588
/
4, although NMR studies show that often the solutions
contain a mixture of species. The isolated complexes
1
were identified by a combination of analysis, IR, H,
31P{1H} and 45Sc NMR spectroscopy, which also
revealed that many retain lattice solvent even after
prolonged drying in vacuum. The very poorly soluble
ScF3×
/
1/2H2O did not react with Ph3PO or Me3PO in
boiling ethanol or acetone even with extended reaction
times.
2.2. [ScX2(Ph3PO)4]X
The reaction of ScX3×
/
nH2O with Ph3PO in ethanol in
molar ratios 1:3Á6 resulted in white [ScCl2(Ph3PO)4]Cl,
/
[ScBr2(Ph3PO)4]Br and yellow [ScI2(Ph3PO)4]I (Table
1). Attempts to isolate [ScX3(Ph3PO)3] using low
ScX3:Ph3PO ratios or other solvents were unsuccessful.
The presence of six-coordinate cations with O4X2 donor
sets was confirmed by an X-ray crystal structure of
Fig. 1. View of the cation in [ScBr2(Ph3PO)4]Br×1/2Et2O showing the
atom numbering scheme. Ellipsoids are drawn at the 40% probability
level and H atoms omitted for clarity.
/
[ScBr2(Ph3PO)4]Br×
/
1/2Et2O, which (Fig. 1, Table 2)
Table 1
45Sc and 31P{1H} NMR data
a
reveals a trans octahedral cation with Brꢀ
close to linear 179.04(5)8 and BrꢀScꢀO 88.6(3)8Á
91.3(3)8. The angles ScꢀOꢀP are variable approximately
154Á1668. The ScꢀO(P) distances, approximately 2.07
/
Scꢀ
/
Br very
45Sc(w1/2
(Hz))
31P{1H}
Solvent
/
/
/
/
/
/
/
[ScCl2(Ph3PO)4]Cl
75(850)
34.5
CH2Cl2 Á
CDCl3
/
˚
A, are very similar to the values [7] in
b
[Sc(Ph3PO)2(NO3)3] or [Sc(Ph2MePO)4(NO3)2]ꢃ, whilst
˚
Br distances 2.652(1), 2.661(1) A appear to be
[ScCl3(Ph3PO)3]
121(1400)
108(4500)
47.0(250)
85.0(360)
4.4(sept)
51.5(850)
4.2(sept)
96(4000)
140(20 000)
56(80)
34.0, 33.0
35.8
CH2Cl2 Á
CDCl3
/
the Scꢀ
/
[ScBr2(Ph3PO)4]Br
[ScCl(Me3PO)5]Cl2
[ScCl2(Me3PO)4]Cl
CH2Cl2 Á
CDCl3
/
the first reported. The IR spectrum of each complex
contains one very strong broad feature in the range
56.0, 54.5
54.0(?)
MeNO2 Á
CDCl3
/
1150Á
1130 cmꢁ1 assignable as n(PO), which may be
/
b
compared with 1195 cmꢁ1 in the ‘free’ ligand [7]. In
CH2Cl2 solution [ScCl2(Ph3PO)4]Cl approximates to a
1:1 electrolyte1 and in the 31P{1H} NMR spectrum there
is a main feature at d 34.5 attributed to the tetra-
kis(Ph3PO) complex, and weaker features at 26.0
(Ph3PO), 34.0, 33.0. The corresponding 45Sc NMR
spectrum has a broad resonance at d 75 and a weaker
broader resonance at d 121. Addition of excess Ph3PO
to these solutions results in the loss of the weaker
MeNO2 Á
CDCl3
/
c
[Sc(Me3PO)6]Br3
57.0(eight
lines)
MeNO2 Á
CDCl3
/
b
[ScBr(Me3PO)5]Br2
56.5, 55.0
MeNO2 Á
CDCl3
/
c
[Sc(Me3PO)6]I3
57.0 (eight
lines)
MeNO2 Á
CDCl3
/
[Sc(Ph3AsO)4Cl2]Cl
CH2Cl2 Á
CDCl3
/
[Sc(Ph3AsO)4Br2]Br
[Sc(Me3AsO)6]Cl3
[Sc(Me3AsO)6]Br3
[Sc(Me3AsO)6]I3
CH2Cl2 Á
CDCl3
/
MeNO2 Á
CDCl3
/
Table 2
˚
Selected bond lengths (A) and angles (8) for [ScBr2(Ph3PO)4]Br×
1/2Et2O
56(70)
MeNO2 Á
CDCl3
/
56(70)
MeNO2 Á
/
Bond lengths
CDCl3
Sc(1)ꢀBr(1)
Sc(1)ꢀO(1)
Sc(1)ꢀO(2)
PꢀO
2.652(1)
2.090(4)
2.057(4)
Sc(1)ꢀBr(2)
Sc(1)ꢀO(3)
Sc(1)ꢀO(4)
2.661(1)
2.059(4)
2.074(4)
[ScCl3(Ph2MePO)3]
123(1100)
80(2000)
40.5, 42.5
42.4
CH2Cl2 Á
CDCl3
/
b
[ScCl2(Ph2MePO)4]Cl
CH2Cl2 Á
CDCl3
/
1.504(4)Á
1.512(4)
/
[ScBr2(Ph2MePO)4]Br 100(8000)
41.0
CH2Cl2 Á
CDCl3
/
Bond angles
Br(1)ꢀSc(1)ꢀBr(2) 179.04(5)
Sc(1)ꢀO(1)ꢀP(1) 153.6(2)
Sc(1)ꢀO(2)ꢀP(2) 159.1(3)
BrꢀSc(1)ꢀO
Sc(1)ꢀO(3)ꢀP(3) 163.0(2)
Sc(1)ꢀO(4)ꢀP(4) 166.5(2)
88.6(3)Á91.3(3)
/
a
All spectra obtained at 295 K in solvent specified.
Species obtained only in solution.
2J(45Scꢀ31P)ꢀ19 Hz.
b
c

N.J. Hill et al. / Polyhedron 21 (2002) 1579Á
/1588
1581
31P{1H} NMR features at 34.0 and 33.0 and the 45Sc
NMR resonance at 121 which are attributed to mer-
[ScCl3(Ph3PO)3]. In the presence of excess Ph3PO,
[ScCl2(Ph3PO)4]Cl is the only complex present in
significant amounts, but in its absence some decomposi-
tion into mer-[ScCl3(Ph3PO)3] occurs. Even a large
excess of Ph3PO fails to produce substitution of further
chloride ligands, in contrast to the corresponding
yttrium systems [10]. The 31P{1H} NMR spectra of
45Sc 4.5, d 31P{1H} 56.5), [ScBr(Me3PO)5]2ꢃ (d 45Sc
51.5, d 31P{1H} 56.0, 55.0), Me3PO, and a minor species
at d 11 in the 45Sc NMR spectrum. Addition of excess
Me3PO shifts the equilibria in favour of
[Sc(Me3PO)6]3ꢃ, although very small amounts of the
other complexes remain evident. In contrast to the initial
solution where the resonances of [Sc(Me3PO)6]3ꢃ in
both 45Sc and 31P{1H} NMR spectra are broad with ill-
defined coupling, in the presence of excess Me3PO well
resolved couplings are seen (Fig. 2) confirming the
presence of the quadrupolar scandium in a cubic
symmetry environment where relaxation is slow. The
trends are continued in [Sc(Me3PO)6]I3 in that the
[Sc(Me3PO)6]3ꢃ cation is the only major species in
solution even in the absence of added Me3PO (there is
also a feature at d 11 in the 45Sc spectrum). The weak
feature in the 45Sc NMR spectra of all three complexes
at d approximately 11 is attributed to a solvento-
complex [Sc(Me3PO)6ꢁn(MeNO2)n]3ꢃ since the reso-
nance is suppressed by addition of Me3PO, and more-
over is absent if the spectra are recorded in Me2CO
solution (although solubility in acetone is very poor).
[ScX2(Ph3PO)4]X (XꢀBr or I) in CH2Cl2 solution show
/
only a single resonance in each and the conductances do
not change significantly on addition of Ph3PO, consis-
tent with [ScX2(Ph3PO)4]X as the only species present.
The 45Sc NMR spectrum of the bromide confirms this
with a broad feature at d 108, but the 45Sc resonance of
the iodo-complex is extremely broad (d ca. 200, w1/2 ca.
20 000 Hz) and whilst the d value is reasonable for a
O4I2 set, the line-width could clearly obscure any other
species present.
2.3. [ScCl(Me3PO)5]Cl2 and [Sc(Me3PO)6]X3 (X3ꢀ
/
Br or I)
2.4. [ScX2(Ph3AsO)4]X
The reaction of ScX3×
/
nH2O with Me3PO in a 1:6
molar ratio in ethanol gave [Sc(Me3PO)6]X3 (Xꢀ
/Br or
The reaction of ScX3×
/
nH2O with Ph3AsO in 1:4 molar
I), but only [ScCl(Me3PO)5]Cl2 for the lightest halide.
The complexes are insoluble or poorly soluble in
chlorocarbons, alcohols or acetone, but dissolve in
nitromethane. In nitromethane solution, the 1H,
31P{1H} and 45Sc NMR spectra of [ScCl(Me3PO)5]Cl2
show a mixture of species present, which can be
identified as [ScCl(Me3PO)5]Cl2, [ScCl2(Me3PO)4]Cl (in
ca. equal amounts), Me3PO and some unassigned minor
species. In the presence of excess Me3PO, only
ratio in ethanol gave the trans-[ScX2(Ph3AsO)4]X (Xꢀ
/
Cl or Br) complexes. The iodide complex failed to give
reproducible analytical data, it would appear to be
obtained with a mixture of polyiodideÁiodide counter-
anions, although spectroscopically the cation seems
analogous to those with the lighter halides (cf.
[YI2(Ph3AsO)4]I5) [9]. The identity as trans octahedral
/
[ScCl(Me3PO)5]Cl2 (d 45Scꢀ
47) is present in large
/
amounts, but two weak resonances at d 45Sc 11 and 4
are also seen, the latter due to a small amount of
[Sc(Me3PO)6]3ꢃ (see below). The molar conductivity of
a 10ꢁ3 mol dmꢁ3 solution in MeNO2 is 117 Vꢁ1 cm2
molꢁ1, intermediate between 1:1 and 1:2 electrolytes
and this increases with addition of Me3PO to 180 Vꢁ1
cm2 molꢁ1, showing that excess phosphine oxide shifts
the equilibrium in favour of the pentakis complex. An
attempt to extract the chloride ligand from [ScCl(Me3-
PO)5]Cl2 with SbCl5 in the presence of Me3PO was
unsuccessful. Dissolution of [Sc(Me3PO)6]Br3 in MeNO2
also produces a mixture of complexes which can be
identified by the NMR spectra as [Sc(Me3PO)6]3ꢃ (d
1
CH2Cl2 has rarely been used as a solvent for conductivity
measurements and in the standard review (W.J. Geary, Coord.
Chem. Rev., 7 (1971) 81), some doubts were raised about its value
for this purpose. We have used it here and in previous papers (refs [7Á
/
9]) to correlate with the NMR data obtained in CH2Cl2 solution, and
with the typical conductances for the electrolyte types established using
appropriate tetra-alkylammonium salts.
Fig. 2. 45Sc NMR spectrum of [Sc(Me3PO)6]3ꢃ in MeNO2 at 295 K in
the presence of excess Me3PO.

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N.J. Hill et al. / Polyhedron 21 (2002) 1579Á1588
/
Table 3
in the presence of added ligand. For [ScCl2(Ph3AsO)4]Cl
the 45Sc NMR spectrum is a broad (w1/2 4000 Hz)
resonance at d 96 and there was no evidence for any
dissociation into a tris(Ph3AsO) complex (compare
[ScCl2(Ph3PO)4]Cl above). The 45Sc NMR spectrum of
[ScBr2(Ph3AsO)4]Br has a very broad resonance (w1/2
˚
Selected bond lengths (A) and angles (8) for [ScCl2(Ph3AsO)4]Cl
Bond lengths
Sc(1)ꢀCl(1)
Sc(1)ꢀO(1)
Sc(1)ꢀO(2)
AsꢀO
2.562(4)
2.079(7)
2.089(7)
Sc(1)ꢀCl(2)
Sc(1)ꢀO(3)
Sc(1)ꢀO(4)
2.545(4)
2.059(7)
2.063(7)
1.651(7)Á
1.668(7)
/
18 000 Hz) centred at approximately d 140 (920), whilst
/
we have been unable to observe a 45Sc resonance from
the iodocomplex.
Bond angles
Cl(1)ꢀSc(1)ꢀCl(2) 179.8(1)
Sc(1)ꢀO(1)ꢀAs(1) 146.6(4)
Sc(1)ꢀO(2)ꢀAs(2) 145.4(5)
ClꢀSc(1)ꢀO
Sc(1)ꢀO(3)ꢀAs(3) 147.3(5)
Sc(1)ꢀO(4)ꢀAs(4) 147.5(5)
88.6(3)Á91.3(3)
/
2.5. [Sc(Me3AsO)6]X3
The reaction of ScX3×
/
nH2O with Me3AsO in boiling
cations was established by the X-ray structure of
[ScCl2(Ph3AsO)4]Cl (Table 3, Fig. 3). Like the Ph3PO
complex (above) the scandium cation is trans octahedral
with bond angles at scandium very close to those of a
ethanol readily affords the hexakis(Me3AsO) complexes;
the contrast with [ScCl(Me3PO)5]Cl2 is notable. The
complexes are characterised by a sharp singlet in the 1H
NMR spectra at approximately d 2.1, and a sharp 45Sc
NMR signal at d 56. The IR spectra show three strong
regular octahedron. The Scꢀ
/
Cl distances 2.562(4),
840 cmꢁ1 attributable to
˚
2.545(4) A are approximately 0.15 A longer than
˚
bands in the region 925Á
/
observed in [ScCl3(thf)3] [10] or scandium chloride
n(AsꢀO) and methyl rocking modes. These data com-
/
complexes of crown ethers [11]. The Scꢀ
are very similar to those [8] in the eight-coordinate
[Sc(Ph3AsO)4(NO3)2]ꢃ, but the Scꢀ
OꢀAs angles (Table
P angles in
/O(As) distances
pare well with those reported [7] for [Sc(Me3-
AsO)6](NO3)3, and the presence of [Sc(Me3AsO)6]3ꢃ
cations was confirmed by an X-ray crystal structure of
[Sc(Me3AsO)6]Br3 (Fig. 4, Table 4). As expected the
dimensions of the cation are very similar to those
reported previously for the corresponding nitrate salt
/
/
3) are rather more acute than the Scꢀ
/
Oꢀ
/
[ScBr2(Ph3PO)4]ꢃ. In CH2Cl2 solution the complexes
are 1:1 electrolytes and the conductances increase little
Fig. 3. View of the cation in [ScCl2(Ph3AsO)4]Cl showing the atom numbering scheme. Ellipsoids are drawn at the 40% probability level and H
atoms omitted for clarity.

N.J. Hill et al. / Polyhedron 21 (2002) 1579Á
/1588
1583
Fig. 4. View of the cation in [Sc(Me3AsO)6]Br3 showing the atom numbering scheme. Ellipsoids are drawn at the 40% probability level. The Sc(1) is
located on a centre of symmetry.
2.6. [ScCl3(Ph2MePO)3] and [ScBr2(Ph2MePO)4]Br
Table 4
˚
Selected bond lengths (A) and angles (8) for [Sc(Me3AsO)6]Br3
Isolation of pure complexes containing Ph2MePO
proved difficult and attempts to obtain reproducible
Bond lengths
Sc(1)ꢀO(1)
Sc(1)ꢀO(2)
AsꢀO
2.08(2)
2.11(2)
Sc(1)ꢀO(3)
2.11(2)
products from the ScI3×
/
8H2OÁPh2MePO system in
/
either ethanol or acetone were unsuccessful. The white
solid isolated from the reaction of hydrated ScCl3 with
Ph2MePO in ethanol or acetone was identified as the
[ScCl3(Ph2MePO)3] complex by analysis. In CH2Cl2
solution this complex partially rearranges into
[ScCl2(Ph2MePO)4]ꢃ readily identified by a combina-
tion of 45Sc and 31P{1H} NMR spectroscopy. A small
amount of Ph2MePO is also present and there are weak
features in the 45Sc NMR spectrum which have no
corresponding resonances in the 31P{1H} NMR spec-
trum. From the NMR spectra the two scandium species
are tentatively assigned as mer-[ScCl3(Ph2MePO)3] and
trans-[ScCl2(Ph2MePO)4]ꢃ isomers. Addition of excess
Ph2MePO to the solution converts the scandium to the
[ScCl2(Ph2MePO)4]ꢃ and this is accompanied by the
expected increase in conductance. In contrast the
bromide complex isolated was [ScBr2(Ph2MePO)4]Br,
and in solution in CH2Cl2 this appears to be the only
significant species present and the conductance is that of
a 1:1 electrolyte, showing that [ScBr3(Ph2MePO)3] does
not form.
1.65(2)Á1.69(2)
/
Bond angles
O(1)ꢀSc(1)ꢀO(2) 89.5(6)
O(1)ꢀSc(1)ꢀO(3) 90.5(7)
O(2)ꢀSc(1)ꢀO(3) 88.3(6)
Sc(1)ꢀO(1)ꢀAs(1) 133.8(9)
Sc(1)ꢀO(2)ꢀAs(2) 132.6(10)
Sc(1)ꢀO(3)ꢀAs(3) 146.3(10)
[8], but the structure serves to confirm the ScO6
environment with uncoordinated bromide ions. All
three complexes are 3:1 electrolytes in 10ꢁ3 mol dmꢁ3
MeNO2 solution, although the conductivities increase a
little on addition of Me3AsO, possibly indicating some
small amounts of coordination of halide, which is
suppressed by excess ligand. However, only for
[Sc(Me3AsO)6]Cl3 is there any NMR evidence for a
second complex in MeNO2 solution, with a very weak
1
singlet at d 2.05 in the H, and a broad weak feature at
d 84 in the 45Sc spectrum, which we propose are due to
small amounts of [ScCl(Me3AsO)5]2ꢃ, although this is
Â5% of the concentration of the hexakis-complex.
/

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N.J. Hill et al. / Polyhedron 21 (2002) 1579Á1588
/
2.7. 45Sc NMR data
[ScCl(Me3PO)5]Cl2 and [Sc(Me3PO)6]X3 (Xꢀ
and that [ScX3(R3PO)3] form only with XꢀCl. Com-
parison with the yttrium halide systems [9] shows that
whilst both metals form [MX2(Ph3EO)4]X (EꢀAs or P),
in the presence of excess Ph3PO, the yttrium systems
also form [YX(Ph3EO)5]2ꢃ, whereas we have no evi-
dence for pentakis complexes in the scandium systems.
This is probably due to the smaller radius of scandium
/
Br or I),
/
The use of 45Sc and 31P NMR spectroscopy to identify
solution species has been discussed in previous sections.
There are advantages and disadvantages to both nuclei
/
in these systems. The Iꢀ
but the chemical shifts vary little between complexes in
each ScX3ÁR3PO system, and coincidence or only
/
1/2 31P nucleus is very sensitive,
/
partial resolution of resonances is a concern when
identifying minor species or isomers present. The 45Sc
nucleus is also inherently very sensitive, but the line
widths (Table 1) vary greatly and in some systems this
also causes problems. The 45Sc NMR spectra often show
a number of weak and usually sharp resonances in
addition to those of the major species, which we
tentatively assign to hydrolysis/solvolysis impurities in
solution, although there remains the possibility that
some are due to other isomers of the phosphine oxide
complexes. In situ 45Sc NMR studies by Kirakosyan et
(rꢀ83 vs. 106 pm for Y) which may be unable to
/
accommodate more than four bulky Ph3EO ligands. For
both metals the affinity for R3AsO is greater than for
R3PO.
4. Experimental
Multinuclear NMR spectra were obtained on a
Bruker DPX400 at 161.9 MHz (31P{1H}) and referenced
to external 85% H3PO4, 97.2 MHz (45Sc) and referenced
to 1 mol dmꢁ3 Sc(NO3)3 in water at pH 1. Other
physical measurements were made as before [7]. Ph3PO,
Ph2MePO, Ph3AsO (Aldrich) and Me3PO (ALFA) were
used as received. Me3AsO was made by H2O2 oxidation
of Me3As in diethyl ether and purified by sublimation in
al. [12,13], on ScCl3Á
/
(RO)3PO (L) systems (RꢀMe, Et
/
or Bu) identified a range of complexes including
[ScClL5]2ꢃ, cis- and trans-[ScCl2L4]2ꢃ, fac- and mer-
[ScCl3L3], cis- and trans-[ScCl4L2]ꢁ. In these phosphate
systems the line-widths are much smaller than in the
present phosphine oxides and often partial resolution of
vacuo [8]. ScF3×
aqueous solutions of Sc2(SO4)3 and NaF, washed with
6H2O was prepared by
/1/2H2O was made by precipitation from
45Scꢀ
/
31P couplings were seen. The line widths in the
present complexes increase ClB
/
BrꢀI and in several
/
water and dried in vacuo. ScBr3×
/
cases we were unable to observe resonances from the
iodo-complexes. There is also a significant increase in
evaporating Sc2O3 with 48% HBr, and recrystallising the
product from H2O. Yield 79% (Found: Br, 60.8. Calc.
line-width R3POBR3AsO in the halide systems. The
/
for ScBr3×
/
6H2O: Br, 61.0%). ScCl3×
/
6H2O and ScI3×
/
broad lines indicate that the electric field gradient is
substantial, promoting fast quadrupolar relaxation of
8H2O were made by metathesis of aqueous solutions
of scandium sulfate and the appropriate barium halide,
removal of the precipitated BaSO4, and evaporation to
the 45Sc nucleus. The increasing line width Cl0
/
Br0
/
I is
predictable as the disparity in electron density increases
between the hard O (of Ph3AsO) and the increasingly
soft halide, but clearly the effect is much greater than in
the Ph3PO analogues. We have shown elsewhere [8] that
dryness in vacuo. ScCl3×
40.8. Calc. for ScCl3×6H2O: Cl, 41.0%). ScI3×
86% (Found: I, 66.7. Calc. for ScI3×8H2O: I, 66.8%).
/6H2O yield 90% (Found: Cl,
/
/8H2O yield
/
the donor power towards oxophilic metals is R3AsOꢁ
/
R3PO and this is manifested here in increased electric
field asymmetry. The 45Sc NMR chemical shifts show
systematic trends with donor set (Table 1, Scheme 1) the
4.1. [ScCl(Me3PO)5]Cl2
Ice-cold ethanol solutions (10 cm3) of ScCl3×
/
6H2O
d(45Sc) shifting to high frequency with halide Cl0
/
Br0
/
(0.13 g, 0.5 mmol) and Me3PO (0.28 g, 3.0 mmol) were
mixed, stirred for 1 h and then concentrated to
approximately 5 cm3 and refrigerated overnight. The
white solid was filtered off and dried in vacuo. Yield
0.24 g, 63%. (Found: C, 29.7; H, 8.1. Calc. for
C15H45Cl3O5P5Sc: C, 29.4; H, 7.4%). IR (cmꢁ1) (CsI
disc): 2964w, 2896w, 1421w, 1360w, 1299m, 1182w,
1109br,vs (PO), 959s, 872s, 845m, 762s, 682m, 559w,
I and R3PO0
/
R3AsO. This pattern is also seen in the
89Y NMR shifts of the yttrium analogues [9]. As
discussed above, only for [Sc(Me3PO)6]3ꢃ were
31Pꢀ
/
45Sc couplings resolved (Fig. 2). We also note that
intermolecular exchange with added R3PO or R3AsO is
slow on the NMR time-scales in these systems.
1
2
427s. H NMR (300 K, CD3NO2): 1.5(d) J(31Pꢀ
14 Hz (Me3PO); 1.90(d) 2J(31Pꢀ1H)ꢀ
14 Hz
([ScCl2(Me3PO)4]ꢃ);
1.8(d) [4H] 1.70(d) [H]
2J(31Pꢀ1H)ꢀ14 Hz ([ScCl(Me3PO)5]2ꢃ). 31P{1H}
/
1H)ꢀ
/
3. Conclusions
/
/
All the scandium halide complexes isolated are based
upon six-coordinate metal centres. The results also
suggest that the affinity of scandium for chloride is
much greater than for the heavier halides; compare
/
/
NMR (MeNO2) 36.5 (Me3PO), 54.0 ([ScCl2-
(Me3PO)4]ꢃ), 54.5 [P], 56.0 [4P] [ScCl(Me3PO)5]2ꢃ).
45Sc NMR (MeNO2) 47.0 ([ScCl(Me3PO)5]2ꢃ), 84.5

N.J. Hill et al. / Polyhedron 21 (2002) 1579Á
/1588
1585
Scheme 1. Systematic trends in the 45Sc NMR chemical shifts. The values under formulae are the chemical shift, values over arrows the chemical shift
differences. Data for the hexahaloscandate ions are taken from Ref. [6].
([ScCl2(Me3PO)4]ꢃ). LM (10ꢁ3 mol dmꢁ3 MeNO2)ꢀ
117 Vꢁ1 cm2 molꢁ1, ꢃ
XS Me3PO 180.
/
1421m, 1360w, 1312m, 1299m, 1184w, 1108vbr s (PO),
957s, 871s, 761m, 681m, 427s. 1H NMR (300 K,
CD3NO2): 1.1(t) [3H], 3.4(q) [2H] (EtOH), 1.88(d)
/
[54H] 2J(31Pꢀ
/
1H)ꢀ
/
13 Hz ([Sc(Me3PO)6]3ꢃ); 1.82Á
/
4.2. [Sc(Me3PO)6]Br3
1.78(br). 31P{1H} NMR (MeNO2) approximately
57.5(s) ([Sc(Me3PO)6]3ꢃ). 45Sc NMR (MeNO2) 4.0
([Sc(Me3PO)6]3ꢃ), 9.0. LM (10ꢁ3 mol dmꢁ3
A solution of ScBr3×6H2O (0.20 g, 0.50 mmol) in ice-
/
cold ethanol (10 cm3) was treated with Me3PO (0.28 g,
3.0 mmol) in ethanol (5 cm3), resulting in an immediate
white precipitate. After stirring for 1 h, the solid was
filtered off and dried in vacuo. Yield 0.29 g, 54%.
(Found: C, 25.2; H, 6.6. Calc. for C18H54Br3O6P6Sc: C,
25.8; H, 6.5%). IR (cmꢁ1) (CsI disc): 2964w, 2897w,
1422m, 1361w, 1312m, 1299m, 1183w, 1110vbr s (PO),
MeNO2)ꢀ
4.4. [ScCl2(Ph3PO)4]Cl
Warm (60 8C) ethanol solutions (10 cm3) of ScCl3×
/
189 Vꢁ1 cm2 molꢁ1, ꢃ
/XS Me3PO 242.
/
6H2O (0.13 g, 0.5 mmol) and Ph3PO (0.55 g, 2.0 mmol)
were mixed, concentrated to approximately 10 cm3 and
then refrigerated for 1 h. The white solid was filtered off
and dried in vacuo. Yield 0.35 g, 50%. (Found: C, 68.4;
H, 4.7. Calc. for C72H60Cl3O4P4Sc: C, 68.4; H, 4.8%).
IR (cmꢁ1) (CsI disc): 3055w, 1624w, 1591w, 1439m,
1358w, 1191w, 1152s (PO), 1122s, 1091s, 1046w, 1029w,
999m, 751m, 726s, 697s, 544s, 473m, 460m, 445m, 430m.
1
960s, 872s, 762m, 682m, 428s, 418s. H NMR (300 K,
CD3NO2): 1.5(d) J(31Pꢀ
2
/
1H)ꢀ
14 Hz (Me3PO); 1.85(d)
/
2J(31Pꢀ
/
1H)ꢀ14 Hz ([Sc(Me3PO)6]3ꢃ); 1.70(d) [H],
/
1.85(d) [4H] J(31Pꢀ
/
1H)ꢀ14 Hz ([ScBr(Me3PO)5]2ꢃ).
/
2
31P{1H} NMR (MeNO2) 36.5 (Me3PO), 56.5(m)
([Sc(Me3PO)6]3ꢃ), 56.0 [4P], 55.0 [P] ([ScBr(Me3-
PO)5]2ꢃ). 45Sc NMR (MeNO2) 51.5 ([ScBr(Me3-
PO)5]2ꢃ), 4.5 ([Sc(Me3PO)6]3ꢃ). LM (10ꢁ3 mol dmꢁ3
1H NMR (CDCl3) 7.0Á7.9(m). 31P{1H} NMR (CH2Cl2)
/
MeNO2)ꢀ
/
179 Vꢁ1 cm2 molꢁ1, ꢃ
/
XS Me3PO 221.
34.5 ([ScCl2(Ph3PO)4]ꢃ), 34.0 [2P], 33.0 [P]
([ScCl3(Ph3PO)3]), 26.0 (Ph3PO). 45Sc NMR (CH2Cl2)
76 ([ScCl2(Ph3PO)4]ꢃ), 121 ([ScCl3(Ph3PO)3]). LM
4.3. [Sc(Me3PO)6]I3×/EtOH
(10ꢁ3 mol dmꢁ3 CH2Cl2)ꢀ
Ph3PO 22.
/
17 Vꢁ1 cm2 molꢁ1, ꢃ
/XS
Me3PO (0.14 g, 1.5 mmol) and ScI3×
0.25 mmol) were dissolved separately in boiling ethanol
(2ꢂ
5 cm3) and the solutions mixed to yield a pale
/8H2O (0.11 g,
/
4.5. [ScBr2(Ph3PO)4]Br×/CH2Cl2
yellow precipitate. After stirring for 1 h this was filtered
off and dried in vacuo. Yield 0.14 g, 67%. (Found: C,
24.2; H, 6.1. Calc. for C20H60I3O7P6Sc: C, 23.6; H,
5.9%). IR (cmꢁ1) (CsI disc): 3480br, 2964w, 2898w,
A solution of ScBr3×
/
6H2O (0.39 g, 1.0 mmol) in ice-
cold ethanol (10 cm3) was added to Ph3PO (1.11 g, 4.0
mmol) in ethanol (5 cm3) and stirred for 1 h. The

1586
N.J. Hill et al. / Polyhedron 21 (2002) 1579Á1588
/
solution was refrigerated and the white solid filtered off
and dried in vacuo. It was recrystallised by dissolving in
CH2Cl2 and diffusion of diethyl ether. Yield 0.84 g, 60%.
(Found: C, 59.0; H, 4.5. Calc. for C73H62Br3Cl2O4P4Sc:
C, 59.1; H, 4.2%). IR (cmꢁ1) (CsI disc): 3056w, 1620w,
1591w, 1438m, 1358w, 1188w, 1137s(PO), 1120s, 1084s,
1028m, 1000m, 750m, 725s, 692s, 547s, 465m, 454m,
426w, 317m, 306m, 269m, 255m. 1H NMR (CDCl3)
4.9. [ScI2(Ph3AsO)4]I
[ScI2(Ph3AsO)4]I was made similarly as a mustard
coloured solid (46%). Not obtained analytically pure see
text. IR (cmꢁ1) (CsI disc): 3300m, 1636w, 1439m,
1359w, 1185w, 1161w, 1088s, 1027w, 998m, 883s,br
(AsO), 739s, 690s, 477m, 457m, 419m. 1H NMR
(CDCl3) 7.15Á
served. LM (10ꢁ3 mol dmꢁ3 CH2Cl2)ꢀ
molꢁ1, ꢃ
XS Ph3AsO 23.
/
7.7(m). 45Sc NMR (CH2Cl2) not ob-
20 Vꢁ1 cm2
7.0Á
(CH2Cl2) 35.8. 45Sc NMR (CH2Cl2) 108. LM (10ꢁ3
mol dmꢁ3 CH2Cl2)ꢀ21 Vꢁ1 cm2 molꢁ1, ꢃ
XS Ph3PO
23.
/
7.6(m) [30H], 5.2 [H] (CH2Cl2). 31P{1H} NMR
/
/
/
/
4.10. [Sc(Me3AsO)6]Cl3
4.6. [ScI2(Ph3PO)4]I×
/
2H2O
Scandium chloride hydrate (0.05 g, 0.19 mmol) was
dissolved in boiling ethanol (10 cm3) and added to a
solution of Me3AsO (0.21 g, 1.5 mmol) in ethanol (10
cm3), resulting in a white suspension. The solution was
concentrated to approximately 10 cm3 and the white
solid filtered off and dried in vacuo. Yield 0.13 g, 71%.
(Found: C, 22.1; H, 5.6. Calc. For C18H54As6Cl3O6Sc:
C, 22.3; H, 5.6%). IR (cmꢁ1) (CsI disc): 2981w, 2904w,
1418m, 1359w, 1295w, 1269m, 1114w, 924s, 874s, 844s,
647s, 420m. 1H NMR (300 K, CD3NO2): 2.1(s), 2.05(w).
45Sc NMR (MeNO2) 56.0 ([Sc(Me3AsO)6]3ꢃ), 84(vw)
This was made similarly to the chloride analogue, as a
pale yellow solid. Yield 44%. (Found: C, 54.7; H, 3.7.
Calc. for C72H64I3O6P4Sc: C, 54.9; H, 4.1%). IR (cmꢁ1
)
(CsI disc): 3466br, 3054w, 1624w, 1590w, 1438m,
1359w, 1187w, 1132s(PO), 1122s, 1073s, 1027m, 999m,
1
750m, 725s, 693s, 543s, 464m, 452m, 425w. H NMR
(CDCl3) 7.0Á
NMR (CH2Cl2) 38.0. 45Sc NMR (CH2Cl2) approxi-
mately 200 vbr. LM (10ꢁ3 mol dmꢁ3 CH2Cl2)ꢀ22 Vꢁ1
cm2 molꢁ1
/
7.7(m) [60H], 1.7 [4H] (H2O). 31P{1H}
/
.
([ScCl(Me3AsO)5]Cl2). LM (10ꢁ3 mol dmꢁ3 MeNO2)ꢀ
/
214 Vꢁ1 cm2 molꢁ1, ꢃ
/XS Me3AsO 251.
4.7. [ScCl2(Ph3AsO)4]Cl×
/
2EtOH
4.11. [Sc(Me3AsO)6]Br3
An ethanol solution (5 cm3) of Ph3AsO (0.32 g, 1.0
mmol) was added to a solution of ScCl3×
/
6H2O (0.06 g,
[Sc(Me3AsO)6]Br3 was made similarly. Yield 62%.
(Found: C, 19.0; H, 5.0. Calc. for C18H54As6Br3O6Sc: C,
19.6; H, 5.0%). IR (cmꢁ1) (CsI disc): 2982w, 2920w,
1653w, 1418m, 1359m, 1268m, 1088m, 926s, 874s, 846s,
0.25 mmol) in boiling ethanol (10 cm3). The mixture was
concentrated to 5 cm3 and refrigerated overnight. The
white solid was separated and dried in vacuo. Yield 0.24
g, 64%. (Found: C, 58.9; H, 4.5. Calc. for C76H72-
As4Cl3O6Sc: C, 59.5; H, 4.7%). IR (cmꢁ1) (CsI disc):
3407br, 3055w, 1583w, 1485m, 1440m, 1358w, 1187w,
1
648s, 420m. H NMR (300 K, CD3NO2): 2.05(s). 45Sc
NMR (MeNO2) 56.0 ([Sc(Me3AsO)6]3ꢃ). LM (10ꢁ3 mol
dmꢁ3 MeNO2)ꢀ
281.
/
239 Vꢁ1 cm2 molꢁ1, ꢃ
/XS Me3AsO
1162w, 1089s, 1070w, 1027m, 999m, 908vs (AsO), 883m,
1
745s, 692s, 480s, 458m. H NMR (CDCl3) 7.0Á
/
7.7(m)
[60H], 1.2(t) [6H], 3.4(q) [4H] (EtOH). 45Sc NMR
(CH2Cl2) 96. LM (10ꢁ3 mol dmꢁ3 CH2Cl2)ꢀ20 Vꢁ1
cm2 molꢁ1, ꢃ
XS Ph3AsO 24.
/
4.12. [Sc(Me3AsO)6]I3×
/
3H2O
/
A solution of ScI3×8H2O (0.10 g, 0.17 mmol) in warm
/
(60 8C) ethanol (10 cm3) was added to a solution of
Me3AsO (0.14 g, 1.0 mmol) resulting in immediate
precipitation of a yellowish solid. After stirring for 1 h
this was filtered off and dried in vacuo. Yield 0.11 g,
53%. (Found: C, 15.8; H, 3.9. Calc. for C18H60-
As6I3O9Sc: C, 16.7; H, 4.6%). IR (cmꢁ1) (CsI disc):
3440br, 2978w, 2902w, 1647w, 1417m, 1359w, 1265m,
4.8. [ScBr2(Ph3AsO)4]Br×
/
5H2O
[ScBr2(Ph3AsO)4]Br×5H2O was made similarly (54%)
/
(Found: C, 51.4; H, 3.6. Calc. for C72H70As4Br3O9Sc: C,
51.9; H, 4.3%). IR (cmꢁ1) (CsI disc): 3400br, 3051w,
1654m, 1582w, 1485m, 1440s, 1354w, 1185m, 1162w,
1088s, 1027w, 999m, 883s (AsO), 762s, 744s, 691s, 482s,
1
1088w, 921s, 872s, 844s, 646s, 420m. H NMR (300 K,
CD3NO2): 2.1(s) [10H], 2.05(vw) 1.7 [H] (H2O). 45Sc
NMR (MeNO2) 56.0 ([Sc(Me3AsO)6]3ꢃ). LM (10ꢁ3 mol
473s, 457m, 413m. 1H NMR (CDCl3) 7.1Á
1.8(br) [11H] (H2O). 45Sc NMR (CH2Cl2) approxi-
mately 140. LM (10ꢁ3 mol dmꢁ3 CH2Cl2)ꢀ19 Vꢁ1
cm2 molꢁ1, ꢃ
XS Ph3AsO 23.
/
6.6(m) [60H],
/
dmꢁ3 MeNO2)ꢀ
280.
/
253 Vꢁ1 cm2 molꢁ1, ꢃ
/XS Me3AsO
/

N.J. Hill et al. / Polyhedron 21 (2002) 1579Á
/1588
1587
4.13. [ScCl3(Ph2MePO)3]×
/
H2O
Yield 0.14 g, 49%. (Found: C, 55.3; H, 4.8. Calc. for
C52H52Br3O4P4Sc: C, 54.3; H, 4.6%). IR (cmꢁ1) (CsI
disc): 3420br, 3050w, 2908w, 1638m, 1486m, 1438s,
1363w, 1138s (PO), 1094m, 1073w, 1028m, 998w, 894s,
Solutions of ScCl3×
/
6H2O (0.06 g, 0.25 mmol) and
Ph2MePO (0.16 g, 0.75 mmol) in boiling acetone (2ꢂ
/
10
cm3) were mixed resulting in a white suspension. Hexane
(10 cm3) was added and the white sticky solid separated
and stirred with diethyl ether for 24 h. The white powder
was dried in vacuo. Yield 0.17 g, 59%. (Found: C, 56.8;
H, 5.1. Calc. for C39H41Cl3O4P3Sc: C, 57.2; H, 5.0%).
IR (cmꢁ1) (CsI disc): 3420br, 3056w, 2913w, 1643m,
1439s, 1359w, 1143s(PO), 1127sh, 1099m, 1028w, 998w,
787m, 746s, 719m, 695s, 515s. 1H NMR (CDCl3):
2
1.92(d) JPH
ꢀ
/
13 Hz, 7.3Á
5000 Hz. 31P{1H} NMR (CH2Cl2) 41.0,
40.3(w). LM (10ꢁ3 mol dmꢁ3 CH2Cl2)ꢀ22 Vꢁ1 cm2
molꢁ1
/
7.9(m). 45Sc NMR (CH2Cl2)
100, w1/2
ꢀ
/
/
.
4.15. X-ray crystallographic studies
1
901s, 783m, 746s, 720m, 696s, 517s, 507sh, 429w. H
2
NMR (CDCl3): 1.7br (H2O), 1.9(d) JPH
ꢀ
/
13 Hz,
7.9(m).
Crystallographic details together with data collection
and refinement parameters are given in Table 5. Crystals
2
2
2.03(d) JPH
ꢀ
/
13 Hz, 2.5(d) JPH
ꢀ
/
13 Hz, 7.3Á
/
45Sc NMR (CH2Cl2) 123 ([ScCl3(Ph2MePO)3]), 80(w)
([ScCl2(Ph2MePO)4]ꢃ). 31P{1H} NMR (CH2Cl2) 29.0
(Ph2MePO), 40.5 [P], 42.5 [2P] [ScCl3(Ph2MePO)3)], 42.4
were obtained by vapour diffusion from MeNO2Á
systems (with excess Me3AsO added for that complex),
or from CH2Cl2ꢀEt2O. Data were recorded from small,
/Et2O
/
[ScCl2(Ph2MePO)4)]ꢃ. LM (10ꢁ3 mol dmꢁ3 CH2Cl2)ꢀ
/
modest quality crystals at low temperature using a
Nonius Kappa CCD diffractometer. The structure
solutions and refinements (on F or F2 (Cl compound))
8 Vꢁ1 cm2 molꢁ1, ꢃ
4.14. [ScBr2(Ph2MePO)4]Br
To a solution of Ph2MePO (0.22 g, 1.0 mmol) in ice-
/XS Ph2MePO 23.
were carried out using standard methods [14Á
/
17] except
for [ScCl2(Ph3AsO)4]Cl which was initially solved and
¯
refined in the triclinic space group P
/
1 (no. 2) (with Zꢀ
/
cold acetone (10 cm3) was added a solution of ScBr3×
/
4). The value of Z caused concern [18]; subsequent re-
examination of the data showed systematic absences
consistent with a monoclinic space group and the
structure was re-solved and refined in this higher
symmetry space group. Anisotropic refinement of
6H2O (0.09 g, 0.25 mmol) in acetone (5 cm3). After
stirring for 1 h, the solution was concentrated to
approximately 5 cm3 and refrigerated overnight. The
white precipitate was filtered off and dried in vacuo.
Table 5
Crystallographic data
a
[ScBr2(Ph3PO)4]Br×1/2Et2O
[ScCl2(Ph3AsO)4]Cl
[Sc(Me3AsO)6]Br3
Formula
M
C72H60Br3O4P4Scꢃ1/2(C4H10O)
1434.89
triclinic
C72H60As4Cl3O4Sc
1440.19
C18H54As6Br3O6Sc
1100.82
Crystal system
Space group
Monoclinic
P21/n (no. 14)
monoclinic
C2/c (no. 15)
17.7475(5)
16.9358(5)
12.5771(4)
90.0
¯
P/1 (no. 2)
˚
a (A)
14.2119(4)
14.7923(4)
17.6032(5)
66.695(2)
80.919(1)
89.302(1)
3351.0(2)
150
18.436(2)
18.946(3)
˚
b (A)
˚
c (A)
18.393(3)
90.0
a (8)
b (8)
90.04(1)
90.0
96.643(1)
90.0
g (8)
3
U (A )
˚
6424.5(18)
120
3754.9(2)
120
T (K)
Z
F(000) (e)
2
1462
4
2912
4
2136
Total number of observations
Number of unique observations (Rint
Max/min transmission
Number of data in refinement
Number of parameters/restraints
46 706
31 012
9826 (0.16)
14 955
)
15012 (0.054)
0.668/0.581
8868 (I ꢁ3s(I))
777/0
4371 (0.093)
0.314/0.288
1581 (I ꢁ3s(I))
96/0
0.269/0.240
9826
758/0
23.33
0.92
m (cmꢁ1
)
20.5
2.13
86.7
1.80
S
R (I ꢁns(I))
R (all data)
0.059 (nꢀ3)
0.081 (nꢀ2, 4002 reflections)
0.217
0.265
0.065 (nꢀ3)
wR2 (all data)
wR (I ꢁns(I))
0.073 (nꢀ3)
0.114 (nꢀ3)
2 1/2
] .
RꢀajjFojꢁjFcjj/ajFoj; wR2ꢀ[a w(Fo2ꢁFc2)2/a wFo
]
4 1/2; wRꢀ[a w(FoꢁFc)2/a wFo
a
˚
Common data: Mo Ka (lꢀ0.71073 A).

1588
N.J. Hill et al. / Polyhedron 21 (2002) 1579Á1588
/
[2] S. Hajela, W.P. Schaefer, J.E. Bercaw, J. Organomet. Chem. 532
(1997) 45.
[Sc(Me3AsO)6]Br3 gave some npd thermal parameters
for O and C and all were subsequently refined with an
isotropic model.
[3] S. Kobayashi, Eur. J. Org. Chem. (1999) 15.
[4] M. Nakajima, Y. Yamaguchi, S. Hashimoto, Chem. Commun.
(2001) 1596.
[5] D. Grosso, P.A. Sermon, J. Mater. Chem. 10 (2000) 359.
[6] D. Rehder, in: P.S. Pregosin (Ed.), Transition Metal NMR,
Elsevier, New York, 1991.
5. Supplementary data
[7] L. Deakin, W. Levason, M.C. Popham, G. Reid, M. Webster, J.
Chem. Soc., Dalton Trans. (2000) 2439.
Crystallographic data for the structures have been
deposited with the Cambridge Crystallographic Data
Centre (CCDC) and given numbers 173058
[8] W. Levason, B. Patel, M.C. Popham, G. Reid, M. Webster,
Polyhedron 20 (2001) 2711.
[9] N.J. Hill, W. Levason, M.C. Popham, G. Reid, M. Webster,
Polyhedron 21 (2002) 445.
[ScBr2(Ph3PO)4]Br×/1/2Et2O, 173059 [Sc(Me3AsO)6]Br3,
173060 [ScCl2(Ph3AsO)4]Cl. Copies of the data can be
obtained on request from The Director, CCDC, 12
[10] J.L. Atwood, K.D. Smith, J. Chem. Soc., Dalton Trans. (1974)
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Union Road, Cambridge, CB2 1EZ, UK (fax: ꢃ44-
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(b) G.R. Willey, P.R. Meehan, M.D. Rudd, M.G.B. Drew, J.
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Acknowledgements
[14] PATTY, The DIRDIF Program System. P.T. Beurskens, G. Admir-
aal, G. Beurskens, W.P. Bosman, S. Garcia-Granda, R.O. Gould,
J.M.M. Smits, C. Smykalla, Technical Report of the Crystal-
lography Laboratory, University of Nijmegen, The Netherlands,
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We thank the EPSRC for support and Professor M.B.
Hursthouse for access to the Nonius Kappa CCD
diffractometer.
[15] G.M. Sheldrick, SHELXS 97, Program for crystal structure
solution, University of Gottingen, 1997.
¨
[16] TEXSAN: Crystal Structure Analysis Package, Molecular Structure
Corporation, The Woodlands, TX, 1997.
[17] G.M. Sheldrick, SHELXL 97, Program for crystal structure
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¨
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