Yttrium halide complexes of phosphine- and arsine oxides: Synthesis, multinuclear NMR and structural studies

Article abstract of DOI:10.1016/S0277-5387(01)01011-7

The reactions of YCl₃·6H₂O, YBr₃·6H₂O and YI₃·8H₂O with Ph₃PO, Ph₃AsO, Ph₂MePO, Me₃PO, Me₃AsO, o-C₆H₄{P(O)Ph

Full text of DOI:10.1016/S0277-5387(01)01011-7

Polyhedron 21 (2002) 445–455
www.elsevier.com/locate/poly
Yttrium halide complexes of phosphine- and arsine oxides:
synthesis, multinuclear NMR and structural studies
Nicholas J. Hill, William Levason *, Michael C. Popham, Gillian Reid,
Michael Webster
Department of Chemistry, Uni6ersity of Southampton, Southampton SO17 1BJ, UK
Received 12 November 2001; accepted 30 November 2001
Abstract
The reactions of YCl3·6H2O, YBr3·6H2O and YI3·8H2O with Ph3PO, Ph3AsO, Ph2MePO, Me3PO, Me3AsO, o-C6H4{P(O)Ph2}2
(ppO2) and Ph2P(O)CH2P(O)Ph2 (dppmO2) have been examined in EtOH or Me2CO solution. Complexes isolated in the solid
state include [YX2(Ph3PO)4]Z (X=Cl, Br or I; Z=X or PF6), [YX3(Ph2MePO)3], [YCl2(Ph2MePO)4]PF6, [YCl(Ph3PO)5][SbCl6]2,
[Y(Me3PO)6]X3, [YX2(Ph3AsO)4]X, [Y(Me3AsO)6]Cl3 and [YCl2(LꢀL)2]Cl (LꢀL=ppO2 or dppmO2) which were characterised by
analysis, IR and multinuclear (1H, 31P{1H} and 89Y) NMR spectroscopy and conductance measurements. The X-ray crystal
structures of [YCl2(Ph3PO)4]Cl·2.5EtOH·H2O, [YBr2(Ph3PO)4]PF6·Et2O and [Y(Me3PO)6]Br3 are reported and discussed. The
solution speciation (in CH2Cl2) in the various systems was examined by variable temperature multinuclear NMR spectroscopy.
The 89Y NMR chemical shifts show systematic trends with donor set which are described. No reaction between these ligands and
YF3·1/2H2O was observed. © 2002 Elsevier Science Ltd. All rights reserved.
Keywords: Yttrium; Phosphine oxide; Arsine oxide; X-ray structures
[Y(R3PO)4(NO3)2]+ and six-coordinate [Y(Me3-
1. Introduction
AsO)6]3+. Curiously little has been reported about
yttrium halide complexes. Reviews [9,10] indicate that
the lanthanides and yttrium form M(Ph3PO)xCl3 com-
plexes (x=4 or 3), claimed as non-conductors in solu-
The chemistry of yttrium is the least studied of any
4d element, although interest has increased in recent
years with applications in oxide materials [1], ethene
and a-olefin polymerisation and ROMP catalysis [2–4],
whilst complexes of the radioisotope 90Y are used in
radiotherapy [5]. The only oxidation state achieved in
aqueous solution, Y(III) [Kr]4d05s0, is diamagnetic and
colourless, and the high lability of many yttrium com-
plexes, has seriously hindered studies. Potentially 89Y
NMR (89Y=100%, I=1/2) spectroscopy could provide
a valuable probe [6], but its poor sensitivity Dc (recep-
tivity relative to 13C) of 0.67, low resonance frequency
J=4.92 MHz, and very long T1’s have restricted stud-
ies. We have recently reported [7,8] detailed studies
of Y(NO3)3 complexes with R3PO and R3AsO lig-
ands which exhibit a range of stoichiometries including
nine-coordinate [Y(R3PO)3(NO3)3], eight-coordinate
tion,
indicating
seven-
and
six-coordination,
respectively. However, consultation of the original ref-
erences often reveals incomplete studies of a few lan-
thanide examples which are taken as characteristic of
the whole series (including Y) [11–13]. Specific infor-
mation on yttrium compounds is sparse [14,15] and
none have been structurally characterised or their solu-
tion behaviour explored. Here we report detailed stud-
ies of complexes of these ligands with yttrium halides
YX3·nH2O (X=F, Cl, Br or I).
2. Results and discussion
2.1. Synthesis
* Corresponding author. Tel.: +44-2380-593-792; fax: +44-2380-
593-781.
E-mail address: wxl@soton.ac.uk (W. Levason).
Reactions of the hydrated yttrium halides (excluding
fluoride) with Ph3PO, Ph3AsO, Ph2MePO, Me3PO and
0277-5387/02/$ - see front matter © 2002 Elsevier Science Ltd. All rights reserved.
PII: S0277-5387(01)01011-7

446
N.J. Hill et al. / Polyhedron 21 (2002) 445–455
Me3AsO in ethanol, acetone or CH2Cl2 were carried
out using a variety of molar ratios and reaction condi-
tions (see Section 2.2). Isolated complexes were iden-
tified by a combination of analysis, IR, 31P{1H} and
89Y NMR spectroscopy. X-ray structures were deter-
mined for three examples. The insoluble YF3·1/2H2O
did not react with Ph3PO or Me3PO in refluxing etha-
nol or acetone even with extended reaction times.
complex is therefore clear. It is notable that in the
nitrate systems, [Y(Me3PO)3(h2-NO3)3] and [Y(Me3-
PO)4(h2-NO3)2]NO3 form, but not [Y(Me3PO)6](NO3)3,
showing that the preference of the oxophilic Y(III) for
nitrate is stronger than for halides. In the halide sys-
tems, reactions using a Y:Me3PO ratio of 1:B6 re-
sulted only in precipitation of [Y(Me3PO)6]X3, albeit in
poor yield.
2.2. [Y(Me3PO)6]X3 (X=Cl, Br or I) and
[Y(Me3AsO)6]Cl3
2.3. [YX2(Ph3PO)4]Z (X=Cl, Br or I; Z=X or PF6)
The reaction of YCl3·6H2O, YBr3·6H2O or YI3·8H2O
with Ph3PO in ethanol in a 1:3–4 mol ratio produced
white [YX2(Ph3PO)4]X (X=Cl or Br) or pale yellow
[YI2(Ph3PO)4]I. If the reactions are conducted in the
The reaction of YX3·nH2O with Me3PO with a
YX3:Me3PO ratio of 1:6 produced [Y(Me3PO)6]X3.
These complexes are insoluble in acetone, CH2Cl2 or
cold ethanol, slightly soluble in MeNO2, and decom-
posed by DMF or DMSO. The IR spectra of these
complexes are superimposable, with a strong broad
feature at 1110 cm−1 assigned as w(PO), which com-
pares with 1161 cm−1 in the ‘free’ ligand. In ni-
tromethane solution all have conductivities in the range
typical of 3:1 electrolytes, and the 1H NMR spectra
2
(d3-MeNO2) each show a doublet with J(31Pꢀ1H)=13
Hz. The 31P{1H} NMR spectra in MeNO2 at 295 K are
singlets at l ꢀ55, which on cooling to 248 K show
doublet coupling to 89Y of ꢀ8 Hz. The poor solubility
in MeNO2 and the relatively high m.p. (244 K) made
obtaining 89Y NMR data very difficult. No 89Y reso-
nances were observed at ambient temperatures, but
from [Y(Me3PO)6]Cl3 in MeNO2 at 245 K after very
long accumulations, a weak multiplet pattern consistent
with the central five lines of a binomial septet
2J(89Yꢀ31P) approximately 8 Hz, was observed at l 133.
The bromide and iodide salts were less soluble than the
chloride and no 89Y spectra were obtained from these.
Confirmation of the composition was obtained from
the X-ray crystal structure of [Y(Me3PO)6]Br3 which
shows the six trimethylphosphine oxide ligands octahe-
drally coordinating to the yttrium (Fig. 1). The yttrium
is located on a centre of symmetry with the OꢀYꢀO
angles close to the idealized values (Table 1). There is
little change in geometry among the three crystallo-
graphically independant phosphine oxides with the
largest variation being in the YꢀOꢀP angle (142°–159°).
As noted before [7], these angles are smaller than those
in complexes of the triphenyl derivative (see later).
The [Y(Me3AsO)6]Cl3 was obtained from hydrated
YCl3 and Me3AsO in ethanol, and has similar proper-
ties to those of [Y(Me3PO)6]Cl3, including a broad
w(AsO) at 877 cm−1, the conductance of a 3:1 elec-
trolyte in 10−3 mol dm−3 MeNO2, l(Me) at 2.0(s) in
Fig. 1. Structure of the cation in [Y(Me3PO)6]Br3 showing the atom
numbering scheme. Thermal ellipsoids are drawn at the 40% proba-
bility level and H atoms omitted for clarity. The yttrium is located on
a centre of symmetry.
Table 1
,
Selected bond lengths (A) and angles (°) for [Y(Me3PO)6]Br3
Bond lengths
Y(1)ꢀO(1)
Y(1)ꢀO(2)
Y(1)ꢀO(3)
P(1)ꢀC
2.214(5)
2.224(5)
2.233(5)
1.763(8)–1.772(8) P(2)ꢀC
1.757(8)–1.778(8)
P(1)ꢀO(1)
P(2)ꢀO(2)
P(3)ꢀO(3)
1.510(6)
1.514(5)
1.514(5)
1.758(8)–1.780(8)
P(3)ꢀC
Bond angles
1
the H NMR spectrum and an 89Y NMR resonance (in
Y(1)ꢀO(1)ꢀP(1)
Y(1)ꢀO(3)ꢀP(3)
O(1)ꢀY(1)ꢀO(3)
O(1)ꢀP(1)ꢀC
158.5(3)
142.1(3)
91.4(2)
Y(1)ꢀO(2)ꢀP(2)
O(1)ꢀY(1)ꢀO(2)
O(2)ꢀY(1)ꢀO(3)
142.5(3)
89.6(2)
90.8(2)
EtNO2 at 185 K) at l 135. The [Y(Me3AsO)6](NO3)3
previously characterised by an X-ray study [8], has
w(AsO)=877 cm−1 and l(89Y) 133, and the presence
of the same octahedral YO6 cation in the present
110.2(4)–112.6(4) O(2)ꢀP(2)ꢀC
111.2(3)–111.7(4)
109.9(4)–111.9(4)
O(3)ꢀP(3)ꢀC

N.J. Hill et al. / Polyhedron 21 (2002) 445–455
447
blets due to coupling to 89Y with 2J(89Yꢀ31P) 10–12 Hz.
The resonances shift to high frequency along the series
Cl“Br“I, and are unchanged on cooling to 200 K.
Dilute solutions of [YX2(Ph3PO)4]X (X=Cl, Br or I)
show weak resonances (55% of the tetrakis signal)
approximately 1 ppm to low frequency of the main
peak, which on cooling the solutions show doublet 89Y
couplings. These resonances disappear on adding
Ph3PO to the solutions and are attributed to some
dissociation into the tris [YX3(Ph3PO)3] complexes. A
CH2Cl2 solution of [YCl2(Ph3PO)4]Cl boiled with
YCl3·6H2O showed three 31P NMR resonances with l
36.0 (tetrakis), 27.0 (Ph3PO) and 34.5 which is probably
due to [YCl3(Ph3PO)3]. The 89Y NMR spectrum ob-
tained from this solution showed two multiplets at l
192 ([YCl2(Ph3PO)4]Cl below) and 242(quartet), the
latter consistent with [YCl3(Ph3PO)3], although at-
Fig. 2. Structure of the cation in [YCl2(Ph3PO)4]Cl·2.5EtOH·H2O
showing the atom numbering scheme. Thermal ellipsoids are drawn
at the 40% probability level and H atoms omitted for clarity.
presence of NH4PF6, the products are [YX2(Ph3PO)4]-
PF6, which apart from features due to PF6− anions are
spectroscopically identical to the X− salts. The isolated
chloro- and bromo-complexes are air and moisture
stable, the iodocomplexes darken slowly in the solid
state and turn brown in a few hours in solution in
chlorocarbon solvents due to liberation of diiodine, and
this is accompanied by the appearance of new phos-
phine oxide resonances in the 31P NMR spectra. The
latter reaction does not occur in the absence of oxygen,
and would appear to involve yttrium-promoted oxida-
tion of the coordinated iodide ligands by oxygen.
The X-ray structures of [YCl2(Ph3PO)4]Cl·
2.5EtOH·H2O and [YBr2(Ph3PO)4]PF6·Et2O (Figs. 2
and 3) reveal trans-octahedral cations with angles at Y
close to the idealized values. The YꢀO distances (Tables
Fig. 3. Structure of the cation in [YBr2(Ph3PO)4]PF6·Et2O showing
the atom numbering scheme. Thermal ellipsoids are drawn at the 40%
probability level and H atoms omitted for clarity.
Table 2
,
Selected bond lengths (A) and angles (°) for [YCl2(Ph3PO)4]Cl·
2.5EtOH·H2O
,
2 and 3) are all very similar (approximately 2.2 A) to
the values found in the hexakis-trimethylphosphine ox-
ide structure (Table 1). The difference in the Yꢀhalogen
distance closely reflects the difference in the ionic radii
Bond lengths
Y(1)ꢀCl(1)
Y(1)ꢀO(1)
Y(1)ꢀO(2)
P(n)ꢀO(n)
(n=1–4)
2.625(1)
2.231(3)
2.226(3)
1.502(4)– PꢀC
1.507(4)
Y(1)ꢀCl(2)
Y(1)ꢀO(3)
Y(1)ꢀO(4)
2.613(2)
2.233(3)
2.223(3)
1.771(6)–1.799(5)
,
of the two halogens (0.14 A). The complexed phosphine
oxide geometry is unexceptional and shows YꢀOꢀP
angles of 167–174° (Cl) and 156–172° (Br) which are in
general larger than the trimethyl derivative (Table 1).
The IR spectra of the complexes each exhibit a very
strong broad feature in the range 1150–1130 cm−1
assignable to w(PO), which move to high frequency
along the series I“Br“Cl. Uncomplexed Ph3PO ex-
hibits w(PO) at 1195 cm−1 [7]. In CH2Cl2 solution the
complexes are 1:1 electrolytes [7], and show 31P{1H}
NMR resonances at room temperature which are dou-
Bond angles
Cl(1)ꢀY(1)ꢀCl(2) 177.14(4) Cl(1)ꢀY(1)ꢀO(1)
87.10(9)
87.09(9)
88.2(1)
91.7(1)
167.1(2)
Cl(1)ꢀY(1)ꢀO(2)
Cl(1)ꢀY(1)ꢀO(4)
O(1)ꢀY(1)ꢀO(4)
O(3)ꢀY(1)ꢀO(4)
Y(1)ꢀO(2)ꢀP(2)
Y(1)ꢀO(4)ꢀP(4)
90.18(9) Cl(1)ꢀY(1)ꢀO(3)
91.49(9) O(1)ꢀY(1)ꢀO(2)
90.1(1)
90.2(1)
172.2(2)
173.8(2)
O(2)ꢀY(1)ꢀO(3)
Y(1)ꢀO(1)ꢀP(1)
Y(1)ꢀO(3)ꢀP(3)
OꢀPꢀC
170.1(2)
108.3(2)–112.5(2)

448
N.J. Hill et al. / Polyhedron 21 (2002) 445–455
Table 3
sextet pattern, although the outer lines were ill-defined.
This is attributed to the very similar 89Yꢀ31P couplings
to the axial and equatorial phosphine oxides (10, 11
Hz). The w(PO) frequency occurs at 1141 cm−1 for the
dication, some 10 cm−1 lower than in [YCl2(Ph3PO)4]+
showing the effect of the increased positive charge. The
presence of [SbCl6]− is shown by a strong band at 347
cm−1 [17].
,
Selected bond lengths (A) and angles (°) for [YBr2(Ph3PO)4]PF6·Et2O
Bond lengths
Y(1)ꢀBr(1)
Y(1)ꢀO(1)
Y(1)ꢀO(2)
P(n)ꢀ(n)
(n=1–4)
PꢀF
2.775(1)
2.221(5)
2.220(4)
1.501(4)– PꢀC
1.506(5)
Y(1)ꢀBr(2)
Y(1)ꢀO(3)
Y(1)ꢀO(4)
2.794(1)
2.233(5)
2.221(4)
1.779(7)–1.811(8)
1.556(6)–
1.606(5)
2.5. [YX2(Ph3AsO)4]X
Bond angles
Br(1)ꢀY(1)ꢀBr(2) 174.67(4) Br(1)ꢀY(1)ꢀO(1)
87.1(1)
85.8(1)
89.2(2)
95.0(2)
166.7(3)
The corresponding reactions to those in Section 2.3,
but replacing Ph3PO with Ph3AsO, produced
[YX2(Ph3AsO)4]X. The iodide systems are again sensi-
tive to air and, as described in the Section 3, the
polyiodide [YI2(Ph3AsO)4](I5) has been characterised.
Spectroscopically these complexes are very similar to
their phosphine oxide analogues: 1:1 electrolytes in
solution and showing a single broad w(AsO) at approx-
imately 890 cm−1. The 89Y NMR spectra from CH2Cl2
solutions at 200 K contain single sharp resonances
(Table 4) attributable to the [YX2(Ph3AsO)4]+ cations,
the resonances being slightly (510 ppm) to high fre-
quency of those in [YX2(Ph3PO)4]X for constant X. An
acetone solution of [YCl2(Ph3AsO)4]Cl containing 1
equiv. of YCl3 showed (at 200 K) only a singlet 89Y
NMR resonance at l 200 attributable to the tetrakis
complex, with no evidence for formation of
[YCl3(Ph3AsO)3] for which l(89Y) would be expected
approximately l 250–260. The poor sensitivity of 89Y
NMR means that minor species could easily escape
detection, but this shows that the [YCl3(Ph3AsO)3] is
not formed in substantial amounts.
Br(1)ꢀY(1)ꢀO(2)
Br(1)ꢀY(1)ꢀO(4)
O(1)ꢀY(1)ꢀO(4)
O(3)ꢀY(1)ꢀO(4)
Y(1)ꢀO(2)ꢀP(2)
Y(1)ꢀO(4)ꢀP(4)
90.0(1)
95.9(1)
88.2(2)
88.4(2)
172.5(3)
161.4(3)
Br(1)ꢀY(1)ꢀO(3)
O(1)ꢀY(1)ꢀO(2)
O(2)ꢀY(1)ꢀO(3)
Y(1)ꢀO(1)ꢀP(1)
Y(1)ꢀO(3)ꢀP(3)
OꢀPꢀC
155.9(3)
108.5(3)–113.6(3)
tempts to isolate [YCl3(Ph3PO)3] as a solid have been
unsuccessful. Solutions of [YX2(Ph3PO)4]PF6 contain-
ing 2 equiv. of Ph3PO show weak features at l 37.5 and
40.0 (X=Cl) or l 37.0 and 38.0 (X=Br), which by
comparison with data for [YCl(Ph3PO)5][SbCl6]2 may
be identified as due to [YX(Ph3PO)5]2+, suggesting a
competitive equilibrium between X− and Ph3PO for the
Y centre. In these cases insufficient of the second
species was formed to permit its identification via 89Y
NMR. The iodide complexes differ in that mixtures of
[YI2(Ph3PO)4]+ and 5 equiv. of Ph3PO in CH2Cl2 at
ambient temperatures show markedly broadened reso-
nances indicating the onset of intermolecular exchange.
At 180 K this solution shows strong resonances due to
Ph3PO, [YI2(Ph3PO)4]+, intense doublets at l 37.5 and
38.0 (integral 4:1) attributable to formation of
[YI(Ph3PO)5]2+, and some weaker unassigned features.
The greater proportion of [YX(Ph3PO)5]2+ formed
when X=I is consistent with easier displacement of the
soft iodide from the oxophilic yttrium. Solutions of
[YX2(Ph3PO)4]+ fail to exhibit 89Y resonances at 300 K,
but on cooling to 200 K a single resonance is present in
each complex, which under high resolution appear as
binomial quintets due to coupling to four equivalent
R3PO ligands (Table 4, Fig. 4).
2.6. [YX3(Ph2MePO)3]
In marked contrast to the Ph3PO systems, reaction of
YX3·6H2O (X=Cl or Br) with Ph2MePO in ethanol or
acetone irrespective of the ratio gave solid
[YX3(Ph2MePO)3] complexes. The complexes are non-
conductors in solution, and the IR spectra show a very
strong feature in the range 1150–1140 cm−1 at-
tributable to w(PO) (cf. ‘free’ Ph2MePO 1172 cm−1 [7]).
In solution each complex shows a single 31P{1H} NMR
resonance which appear as singlets at ambient tempera-
ture, but show ill-defined doublet couplings to 89Y on
cooling. The 89Y resonances are only observed at 200
K, and under high resolution are binomial quartets
showing coupling to 3 equiv. phosphorus atoms, consis-
tent with a fac geometry (Table 4, Fig. 4). On addition
of Ph2MePO to the solutions very broad 31P NMR
resonances l approximately 29 and 40 were present at
room temperature, showing intermolecular exchange is
occurring. On cooling the resonances sharpen, but in
addition to those of [YX3(Ph2MePO)3] and Ph2MePO,
a new feature is present l approximately 41. In the
2.4. [YCl(Ph3PO)5][SbCl6]2
The reaction of [YCl2(Ph3PO)4]+ with Ph3PO in dry
CH2Cl2 in the presence of 2 equiv. of the strong Lewis
acid SbCl5 results in chloride abstraction to form
[YCl(Ph3PO)5][SbCl6]2. Excess SbCl5 causes decomposi-
tion to form (among other products) [SbCl5(Ph3PO)]
[16] (l (31P)=47) while [Y(Ph3PO)6][SbCl6]3 does not
appear to form. The [YCl(Ph3PO)5][SbCl6]2 shows a
31P{1H} NMR spectrum containing two doublets at l
37.5 and 40.0 (integral 4:1). The corresponding 89Y
NMR resonance is at l 179 and approximates to a

N.J. Hill et al. / Polyhedron 21 (2002) 445–455
449
Table 4
89Y and 31P{1H} NMR data a
l
89Y
l
31P{1H} b
2J(31Pꢀ89Y) (Hz)
Solvent
Temperature (K)
[YCl2(Ph3PO)4]Cl
[YCl2(Ph3PO)4]PF6
[YBr2(Ph3PO)4]Br
[YBr2(Ph3PO)4]PF6
[YI2(Ph3PO)4]I
[YI2(Ph3PO)4]PF6
[YCl2(Ph3AsO)4]Cl
[YBr2(Ph3AsO)4]Br
[YI2(Ph3AsO)4]I
[YCl(Ph3PO)5][SbCl6]2
[YCl3(Ph2MePO)3]
[YBr3(Ph2MePO)3]
[YI3(Ph2MePO)3]
[YCl2(Ph2MePO)4]PF6
[Y(Me3PO)6]Cl3
191 (quintet)
191 (quintet)
220 (quintet)
220 (quintet)
245 (quintet)
245 (quintet)
198 (s)
224 (s)
254 (s)
179 (m)
35.0 (d)
35.0 (d)
36.5 (d)
36.0 (d)
37.5 (d)
37.0 (d)
13
13
11
11
11
11
CH2Cl2/CDCl3
CH2Cl2/CDCl3
CH2Cl2/CDCl3
CH2Cl2/CDCl3
CH2Cl2/CDCl3
CH2Cl2/CDCl3
CH2Cl2/CDCl3
CH2Cl2/CDCl3
CH2Cl2/CDCl3
CH2Cl2/CDCl3
CH2Cl2/CDCl3
CH2Cl2/CDCl3
CH2Cl2/CDCl3
CH2Cl2/CDCl3
MeNO2
200
200
200
200
200
200
200
200
200
200
200
185
180
185
245
245
245
200
200
200
37.5 (d), 40.0 (d)
40.0 (d)
40.0 (d)
41.5 (d)
40.5 (d)
54.0 (d)
55.0 (d)
55.0 (d)
11, 10
10
11
14
10
ca. 9
9
9
256 (quartet)
299 (quartet)
354 c
192 (quintet)
133 (m) c
[Y(Me3PO)6]Br3
[Y(Me3PO)6]I3
[Y(Me3AsO)6]Cl3
[YCl2(ppO2)2]Cl
[YCl2(dppmO2)2]Cl
MeNO2
MeNO2
135 (s)
EtNO2/d6-Me2CO
CH2Cl2/CDCl3
CH2Cl2/CDCl3
210 (quintet)
36.0 (d)
32.0 c
7
213 (multiplet) c
[Y(NO3)3(Ph3PO)3] d
−37.7 (quartet)
−2.0 (quintet)
−17.7 (quartet)
−0.3 (quintet)
21 (s)
d
[Y(NO3)2(Ph3PO)4]NO3
[Y(NO3)3(Me3PO)3] d
d
[Y(NO3)2(Me3PO)4]NO3
[Y(NO3)2(Ph3AsO)4]NO3
[Y(Me3AsO)6](NO3)3
e
e
133 (s)
a The 2J couplings are often not evident at higher temperatures, possibly due to exchange, although in some cases they are probably lost in the
line widths.
b The PF6− resonances at approximately −145 (septet) are not listed; 31P NMR shifts at 300 K are given in Section 3.
c Couplings not resolved or ill-defined.
d Data from Ref. [7].
e Data from Ref. [8].
presence of a large excess of ligand, 89Y NMR spectra
(200 K) showed quintet patterns near l 190 (Cl) or 220
(Br) which by comparison with the Ph3PO analogues
temperature 31P NMR studies reveal the presence of
some Ph2MePO and [YCl3(Ph2MePO)3] in CH2Cl2 solu-
tions of [YCl2(Ph2MePO)4]PF6, showing an equilibrium
is present. The [YBr2(Ph2MePO)4]PF6 was not
prepared.
can
be
attributed
to
the
formation
of
[YX2(Ph2MePO)4]+, although only [YX3(Ph2MePO)3]
were isolated from these solutions as solids. However,
the reaction of YCl3·6H2O, Ph2MePO and NH4PF6 in
The YI3·8H2OꢀPh2MePO system is more labile and
isolation of pure complexes proved difficult. A pale
yellow [YI3(Ph2MePO)3] was isolated from ethanol so-
lution containing a YI3:Ph2MePO of 1:2. At 180 K in
CH2Cl2 solution this shows a rather broad 89Y reso-
nance at l 354 which seems reasonable for an I3O3
donor set (see Table 4), but the coupling was not clearly
resolved. The 31P NMR spectrum has a very broad
feature at l 41.5 at 300 K which on cooling sharpens
and at 190 K shows a doublet at 41.5 (2J(89Yꢀ31P)=14
Hz) and some other weak features to higher frequency.
In the [YI3(Ph2MePO)3] with excess Ph2MePO, ligand
exchange is fast on the 31P NMR time scale down to
low temperatures, and even at 190 K the lines are still
broad, although separate resonances at 29.0
(Ph2MePO), 41.5 (d) ([YI3(Ph2MePO)3]) and 42.0 (d)
([YI2(Ph2MePO)4]+ ?) are resolved. The corresponding
YI3/Ph2MePO/PF6− system is complex and appears to
ethanol
in
a
1:4:1
ratio
produced
white
[YCl2(Ph2MePO)4]PF6, which showed a quintet 89Y
NMR resonance at l 192 and l(31P) at 40.5. Low
Fig. 4. 89Y NMR spectra of: (a) [YCl2(Ph3PO)4]+
;
(b)
[YBr3(Ph2MePO)3] in CH2Cl2/CDCl3 at 200 K.

450
N.J. Hill et al. / Polyhedron 21 (2002) 445–455
Scheme 1. 89Y NMR chemical shifts of various yttrium complexes. Values below formulae represent chemical shifts and values alongside the
arrows are the differences in chemical shift. For practical reasons (see text) the [Y(Me3EO)6]3+ were recorded in MeNO2 or EtNO2, and the others
in CH2Cl2. Although small solvent and temperature shifts may be present in the data, they are unlikely to alter the pattern of characteristic shifts
with X, R3EO, and X:R3EO ratio, which are clear.
contain at least three yttrium species, but attempts to
isolate pure solid complexes from this system failed.
small, and changing R3PO to R3AsO produces a high
frequency shift of 510 ppm. The homoleptic
[Y(Me3EO)6]3+ (E=P or As) have l(89Y) 133–135.
Incorporating Cl in the coordination sphere in
2.7. Diphosphine dioxide complexes
[YCl(Ph3PO)5]2+
,
[YCl2(Ph3PO)4]+ and [YCl3(Ph2-
The reaction of YCl3·6H2O with Ph2P(O)CH2P-
(O)Ph2 (dppmO2) or o-C6H4{P(O)Ph2}2 (ppO2) in etha-
nol gave white [YCl2(LꢀL)2]Cl, which appear to be
the first reported diphosphine dioxide complexes of
yttrium. Both are 1:1 electrolytes in CH2Cl2 solution.
The [YCl2(ppO2)2]Cl exhibits a single broad 31P{1H}
NMR resonance at ambient temperatures and no 89Y
resonance is evident. However, at 200 K the 89Y NMR
spectrum shows a clearly resolved quintet at l 210
(2J(89Yꢀ31P)=7 Hz) showing it is the trans cation with
a Cl2O4 donor set. The [YCl2(dppmO2)2]Cl is generally
similar although its solubility in CH2Cl2 is poor.
MePO)3] causes a stepwise high frequency shift. Simi-
larly exchanging Cl for Br and then I causes progressive
high frequency shifts (Scheme 1). Comparison with
data on the nitrate systems (Table 4) shows that re-
placement of NO3 by R3EO results in a high frequency
shift, although the trends are less regular, probably due
to the varying coordination numbers in the nitrate
systems. The 31P{1H} chemical shifts are much less
useful in identifying complexes since they differ by
approximately 1–2 ppm between [YX2(R3PO)4]+ and
[YX3(R3PO)3].
2.8. 89Y NMR studies
3. Experimental
The identification of solution species as discussed in
previous sections relied in most cases on the 31Pꢀ89Y
coupling patterns. Here we compare chemical shifts in
an attempt to correlate these with donor set. Data from
our previous studies of the nitrate systems are also
included. Scheme 1 shows the systematic changes ob-
served as the nature and number of X and R3EO
ligands are varied. As expected the effect on the 89Y
chemical shift of changing R groups on the ligand is
Multinuclear NMR spectra were obtained on a
Bruker DPX400 at 161.9 MHz (31P{1H}) and refer-
enced to external 85% H3PO4 or 19.60 MHz (89Y) using
a 2–4 s pulse delay and TEMPO as a relaxation agent
and referenced to 1 mol dm−3 YCl3 in water. Other
physical measurements were made as before [7]. Ph3PO,
Ph2MePO, Ph3AsO, YCl3·6H2O (Aldrich) and Me3PO
(Alfa) were used as received. Me3AsO was made by
H2O2 oxidation of Me3As in Et2O and purified by

N.J. Hill et al. / Polyhedron 21 (2002) 445–455
451
sublimation in vacuo [8]. YF3·1/2H2O was made by
precipitation from aq. solutions of Y(NO3)3 and NaF,
washed with H2O and dried in vacuo. YBr3·6H2O was
prepared by evaporating Y2O3 with 48% HBr, and
recrystallising the product from H2O. Anal. Found: Br,
54.8. Calc. for YBr3·6H2O: Br, 54.9%. YI3·8H2O was
made by metathesis of aq. solutions of yttrium sulfate
and barium iodide, removal of the precipitated BaSO4,
and evaporation to dryness in vacuo. The fawn hygro-
scopic solid was stored in a desiccator. Yield: 92%.
Anal. Found: I, 61.9. Calc. for YI3·8H2O: I, 62.0%.
Several attempts to prepare this compound from Y2O3
and aq. HI gave materials containing excess diiodine,
which could not be removed.
CH2Cl2/CDCl3): 36.0 (d) 2J(31Pꢀ89Y)=11 Hz. LM
(10−3 mol dm−3 CH2Cl2)=20 V−1 cm2 mol−1
.
3.4. [YBr2(Ph3PO)4]PF6
Prepared similarly to [YCl2(Ph3PO)4]PF6. Yield: 90%.
Anal. Found: C, 57.9; H, 4.2. Calc. for
C72H60Br2F6O4P5Y: C, 57.4; H, 4.2%. IR (cm−1) (CsI
disc): 3061w, 1439m, 1359w, 1191w, 1147vs (PO),
1123s, 1089s, 1029m, 1000m, 839vs, 750m, 726s, 693s,
559sh, 543s, 449m, 417m, 305m, 250w. 1H NMR
(300 K, CDCl3): 7.2–7.9 (m). 31P{1H} NMR (300
K, CH2Cl2/CDCl3): 36.0 (d) 2J(31Pꢀ89Y)=11 Hz,
−145(septet) PF6−. LM (10−3 mol dm−3 CH2Cl2)=19
V−1 cm2 mol−1
.
3.1. [YCl2(Ph3PO)4]Cl
3.5. [YI2(Ph3PO)4]I
YCl3·6H2O (0.20 g, 0.66 mmol) and Ph3PO (1.11 g,
4.0 mmol) were dissolved separately in cold EtOH
(2×5 cm3) and the solutions mixed. Refrigeration
overnight resulted in colourless crystals, which were
filtered off and dried in vacuo. Yield: 0.56 g, 60%. Anal.
Found: C, 65.7; H, 4.5. Calc. for C72H60Cl3O4P4Y: C,
66.1; H, 4.6%. IR (cm−1) (Nujol mull): 1310m, 1188w,
1150vs (PO), 1119s, 1087s, 1074m, 997w, 975w, 749s,
Prepared similarly to [YCl2(Ph3PO)4]Cl as a pale
yellow solid. Yield: 38%. Anal. Found: C, 54.2; H, 3.8.
Calc. for C72H60I3O4P4Y: C, 54.6; H, 3.8%. IR (cm−1
)
(CsI disc): 1485w, 1438m, 1359m, 1188w, 1136vs (PO),
1121s, 1083s, 1027w, 1000w, 749m, 725s, 696s, 543s,
1
460m, 449m, 421w, 299m. H NMR (300 K, CDCl3):
7.1–7.6 (m). 31P{1H} NMR (300 K, CH2Cl2/CDCl3):
37.2 (d) 2J(31Pꢀ89Y)=11 Hz. LM (10−3 mol dm−3
1
692s, 543s, 420w, 398w, 353w, 310m, 260m. H NMR
(300 K, CDCl3): 7.1–7.9 (m). 31P{1H} NMR (300 K,
CH2Cl2)=25 V−1 cm2 mol−1
.
CH2Cl2/CDCl3): 35.0 (d) 2J(31Pꢀ89Y)=12 Hz. LM
(10−3 mol dm−3 CH2Cl2)=30 V−1 cm2 mol−1
.
3.6. [YI2(Ph3PO)4]PF6
3.2. [YCl2(Ph3PO)4]PF6
Prepared similarly to [YCl2(Ph3PO)4]PF6 as pale yel-
low powder. Yield: 39%. Anal. Found: C, 53.8; H, 3.7.
Calc. for C72H60F6I2O4P5Y: C, 54.0; H, 3.8%. IR
(cm−1) (CsI disc): 1486w, 1439m, 1359w, 1183w,
1144vs (PO), 1122s, 1087s, 1029w, 999m, 842vs, 753m,
To a solution of YCl3·6H2O (0.30 g, 1.0 mmol) in
warm EtOH (10 cm3) were added sequentially
[NH4][PF6] (0.16 g, 1.0 mmol) and Ph3PO (1.1 g, 4.0
mmol) dissolved in EtOH (10 cm3), resulting in a fine
white precipitate. The solution was stirred for 1 h, the
precipitate filtered off and dried in vacuo. Yield: 1.09 g,
75%. Anal. Found: C, 61.1; H, 4.4. Calc. for
C72H60Cl2F6O4P5Y: C, 61.0; H, 4.3%. IR (cm−1) (CsI
disc): 3061w, 1439m, 1318m, 1192w, 1150vs (PO),
1122s, 1092s, 1028m, 999m, 839s, 750m, 725s, 693s,
1
725s, 696s, 559sh, 542s, 460m, 445m, 424m, 304m. H
NMR (300 K, CDCl3): 7.4–7.8 (m). 31P{1H} NMR
2
(300 K, CH2Cl2/CDCl3): 37.5 (d) J(31Pꢀ89Y)=11 Hz,
−145(septet) PF6−. LM (10−3 mol dm−3 CH2Cl2)=23
V−1 cm2 mol−1
.
1
559s, 543s, 459m, 446m, 421m, 305m, 267s. H NMR
3.7. [YCl(Ph3PO)5][SbCl6]2
(300 K, CDCl3): 7.1–7.9 (m). 31P{1H} NMR (300
K, CH2Cl2/CDCl3): 35.0 (d) 2J(31Pꢀ89Y)=13 Hz,
−145(septet) PF6−. LM (10−3 mol dm−3 CH2Cl2)=21
Under a nitrogen atmosphere antimony pentachlo-
ride (0.05 g, 0.17 mmol) was added dropwise to a
solution of [YCl2(Ph3PO)4]Cl (0.11 g, 0.08 mmol) in
anhydrous CH2Cl2 (5 cm3). A solution of Ph3PO (0.02
g, 0.08 mmol) in CH2Cl2 (5 cm3) was added, resulting in
a milky suspension. The solution was concentrated to 5
cm3, the white powder filtered off and dried in vacuo.
Yield: 0.12 g, 56%. Anal. Found: C, 49.6; H, 3.3. Calc.
V−1 cm2 mol−1
.
3.3. [YBr2(Ph3PO)4]Br
Prepared similarly to [YCl2(Ph3PO)4]Cl. Yield: 52%.
Anal. Found: C, 59.6; H, 4.2. Calc. for C72H60Br3-
O4P4Y: C, 59.9; H, 4.2%. IR (cm−1) (CsI disc): 1307m,
1188w, 1140vs (PO), 1119s, 1087s, 1084m, 998w, 973w,
for C90H75Cl13O5P5Sb2Y: C, 49.4; H, 3.5%. IR (cm−1
)
(CsI disc): 2975w, 1484w, 1437m, 1357m, 1191w, 1141s
(PO), 1121s, 1090m, 1027w, 995m, 745s, 692s, 543s,
1
763m, 693s, 543s, 449m, 417w, 305m, 262m. H NMR
(300 K, CDCl3): 7.2–7.9 (m). 31P{1H} NMR (300 K,
347s(SbCl6−). H NMR (300 K, CDCl3): 7.2–7.7 (m).
1

452
N.J. Hill et al. / Polyhedron 21 (2002) 445–455
LM (10−3 mol dm−3 CH2Cl2)=42 V−1 cm2
mol−1
tion overnight deposited white needles. Yield: 0.39 g,
66%. Anal. Found: C, 24.2; H, 6.2. Calc. for
C18H54Br3O6P6Y: C, 24.5; H, 6.1%. IR (cm−1) (CsI
disc): 2962w, 2896w, 1358m, 1299m, 1111s,br (PO),
959s, 872m, 761m, 395s, 364m, 330m. 1H NMR (300 K,
d3-MeNO2): 1.69 (d) 2J(31Pꢀ1H)=13 Hz. LM (10−3
.
3.8. [YCl2(Ph3AsO)4]Cl
YCl3·6H2O (0.30 g, 1.0 mmol) and Ph3AsO (1.28 g,
4.0 mmol) were dissolved in boiling EtOH (10 cm3).
Cooling to room temperature (r.t.) followed by refriger-
ation overnight resulted in white crystals, which were
filtered off and dried in vacuo. Yield: 0.32 g, 20%. Anal.
Found: C, 57.7; H, 3.9. Calc. for C72H60As4Cl3O4Y: C,
58.3; H, 4.1%. IR (cm−1) (CsI disc): 1440m, 1359m,
1186w, 1089m, 1071w, 1026w, 999w, 894vs (AsO), 744s,
mol dm−3 MeNO2)=207 V−1 cm2 mol−1
.
3.13. [Y(Me3PO)6]I3
A boiling EtOH solution (10 cm3) of YI3·8H2O (0.31
g, 0.5 mmol) was added to a solution of Me3PO (0.18 g,
2.0 mmol) resulting in a yellow suspension. The mixture
was refrigerated overnight, the solid filtered off and
dried in vacuo. Yield: 0.21 g, 50%. Anal. Found: C,
20.9; H, 5.4. Calc. for C18H54I3O6P6Y: C, 21.2; H, 5.3%.
IR (cm−1) (CsI disc): 2964w, 2897w, 1421w, 1358m,
1299m, 1110s, br (PO), 957s, 871m, 761m, 396s, 364m,
331m. 1H NMR (300 K, d3-MeNO2): 1.73 (d)
2J(31Pꢀ1H)=13 Hz. LM (10−3 mol dm−3 MeNO2)=
1
693s, 553w, 481s, 376m, 365s, 273m, 260s. H NMR
(300 K, CDCl3): 7.3–7.8. LM (10−3 mol dm−3
CH2Cl2)=31 V−1 cm2 mol−1
.
3.9. [YBr2(Ph3AsO)4]Br
Made similarly to the above. Yield: 55%. Anal.
Found: C, 53.0; H, 3.8. Calc. for C72H60As4Br3O4Y: C,
53.4; H, 3.7%. IR (cm−1) (CsI disc): 1440m, 1359m,
1089m, 1071w, 1025w, 999w, 893vs (AsO), 744s, 691s,
478s, 368s, 338sh, 272m, 243m. 1H NMR (300 K,
CDCl3): 7.2–7.8. LM (10−3 mol dm−3 CH2Cl2)=23
228 V−1 cm2 mol−1
.
3.14. [YCl3(Ph2MePO)3]
A solution of YCl3·6H2O (0.30 g, 1.0 mmol) in
boiling EtOH (10 cm3) was added to a solution of
Ph2MePO (0.22 g, 1.0 mmol) in EtOH (5 cm3) and the
mixture stirred for 1 h, then concentrated to approxi-
mately 5 cm3 and refrigerated overnight. The white
solid was filtered off and dried in vacuo. Yield: 0.28 g,
88%. Anal. Found: C, 54.5; H, 4.1. Calc. for
C39H39Cl3O3P3Y: C, 55.5; H, 4.7%. IR (cm−1) (CsI
disc): 1709w, 1641m, 1439m, 1363w, 1225w, 1148vs
(PO), 1127m, 1101m, 999w, 896m, 783w, 752m, 696m,
614m, 515s, 306w, 254s. 1H NMR (300 K, CDCl3): 2.29
(br), 7.4–7.7 (m). LM (10−3 mol dm−3 CH2Cl2)=2
V−1 cm2 mol−1
.
3.10. [YI2(Ph3AsO)4]I5
Made similarly as dark brown crystals. Yield: 25%.
Anal. Found: C, 38.2; H, 2.9. Calc. for
C72H60As4I7O4Y: C, 38.1; H, 2.7%. IR (cm−1) (CsI
disc): 1484m, 1440m, 1360w, 1186w, 1088s, 1025w,
999m, 893vs (AsO), 740s, 691s, 477s, 457m, 367m,
1
356m, 273w, 244w. H NMR (300 K, CDCl3): 7.2–7.8.
LM (10−3 mol dm−3 CH2Cl2)=41 V−1 cm2 mol−1
3.11. [Y(Me3PO)6]Cl3
.
V−1 cm2 mol−1
.
3.15. [YBr3(Ph2MePO)3]
An ethanolic solution (10 cm3) of YCl3·6H2O (0.15 g,
0.5 mmol) was added to Me3PO (0.28 g, 3.0 mmol) in
EtOH (10 cm3) and the solutions stirred for 1 h.
Refrigeration gave a white precipitate. Yield: 0.34 g,
90%. Anal. Found: C, 28.9; H, 7.6. Calc. for
C18H54Cl3O6P6Y: C, 28.9; H, 7.2%. IR (cm−1) (CsI
disc): 2960w, 1423w, 1358w, 1299w, 1111vs, br (PO),
Made similarly to the above from a 1:3 molar ratio
of YBr3·6H2O: Ph2MePO. Yield: 46%. Anal. Found: C,
48.2; H, 4.1. Calc. for C39H39Br3O3P3Y: C, 47.9; H,
4.0%. IR (cm−1) (CsI disc): 1591w, 1439m, 1358w,
1178sh, 1144vs (PO), 1127sh, 1098s, 998m, 894s, 782w,
1
750s, 720m, 694m, 515s, 503sh, 392w, 312w. H NMR
1
960m, 872m, 762m, 396m, 364w, 332m. H NMR (300
(300 K, CDCl3): 2.18 (br), 7.3–7.7 (m). LM (10−3 mol
K, d3-MeNO2): 1.60 (d) J(31Pꢀ1H)=14 Hz. LM (10−3
dm−3 CH2Cl2)=7 V−1 cm2 mol−1
3.16. [YI3(Ph2MePO)3]
.
2
mol dm−3 MeNO2)=225 V−1 cm2 mol−1
3.12. [Y(Me3PO)6]Br3
.
Prepared similarly using YI3·8H2O and Ph2MePO in
a 1:2 molar ratio, as a yellow powder. Yield: 28%. Anal.
Found: C, 42.5; H, 3.7. Calc. for C39H39I3O3P3Y: C,
41.9; H, 3.5%. IR (cm−1) (CsI disc): 2896w, 1592w,
1439m, 1359w, 1178sh, 1140vs (PO), 1125s, 1093s,
Boiling EtOH solutions (2×10 cm3) of YBr3·6H2O
(0.44 g, 1.0 mmol) and Me3PO (0.37 g, 4.0 mmol) were
mixed, resulting in a white suspension, which redis-
solved on shaking. Refrigeration of the resulting solu-

N.J. Hill et al. / Polyhedron 21 (2002) 445–455
453
1071m, 1029m, 996m, 895s, 786w, 749s, 720m, 696m,
844m, 750s, 730s, 694s, 562s, 549s, 534m. 1H NMR
1
(300 K, CDCl3): 7.2–7.8 (m). LM (10−3 mol dm−3
519s, 478m, 421m, 383w. H NMR (300 K, CDCl3): 2.0
(d), 7.2–7.7 (m). LM (10−3 mol dm−3 CH2Cl2)=5
CH2Cl2)=19 V−1 cm2 mol−1
3.21. Crystallography
.
V−1 cm2 mol−1
.
3.17. [YCl2(Ph2MePO)4]PF6
Crystals of the Ph3PO complexes were obtained by
vapour diffusion from CH2Cl2/Et2O in a refrigerator.
[Y(Me3PO)6]Br3 was obtained directly from the synthe-
sis. Crystallographic details are shown in Table 5; data
were collected on a Nonius–Kappa CCD diffractome-
ter fitted with Mo Ka radiation and graphite
monochromator and the cell dimensions were taken
from the diffractometer software recognizing that the
e.s.d. values are unreasonably small [18]. Structure solu-
tion and refinement were routine [19–21] and data
processing used the SORTAV absorption correction
[22]. Phenyl and methyl H atoms were introduced in
calculated positions. During the structure solution for
two of the compounds, solvent molecules appeared in
the difference electron density maps and these were
modelled. One EtOH molecule was given a reduced
s.o.f. (0.5) in order to obtain adp’s similar to the other
EtOH molecules.
To a solution of YCl3·6H2O (0.15 g, 0.5 mmol) in
boiling EtOH (10 cm3) was added solid NH4PF6 (0.082
g, 0.5 mmol), and the mixture allowed to cool to r.t. A
solution of Ph2MePO (0.43 g, 2.0 mmol) in EtOH (5
cm3) was added resulting in an immediate precipitate.
After some hours this was filtered off, and dried in
vacuo. Yield: 0.28 g, 43%. Anal. Found: C, 53.0; H, 4.4.
Calc. for C52H52Cl2F6O4P5Y: C, 53.4; H, 4.5%. IR
(cm−1) (CsI disc): 1591w, 1486w, 1440m, 1305w,
1165sh, 1151s (PO), 1126m, 1101w, 1075w, 1031w,
1000m, 903s, 840s, 782s, 756s, 748s, 720m, 698s, 559s,
1
511s, 498s, 455m, 418m, 387w, 312m, 264s. H NMR
(300 K, CDCl3): 1.92 (br), 7.2–7.7 (m). LM (10−3 mol
dm−3 CH2Cl2)=20 V−1 cm2 mol−1
.
3.18. [Y(Me3AsO)6]Cl3
YCl3·6H2O (0.15 g, 0.5 mmol) was dissolved in boil-
ing EtOH (10 cm3) and a solution of Me3AsO (0.41 g,
3.0 mmol) in EtOH (10 cm3) added. The solvent was
removed in vacuo, the oil remaining dissolved in cold
C3H6O which on standing produced a colourless pow-
der. Yield: 0.22 g, 43%. Anal. Found: C, 21.0; H, 5.2.
Calc. for C18H54As6Cl3O6Y: C, 21.3; H, 5.4%. IR
(cm−1) (CsI disc): 2896w, 1418m, 1359s, 1269m, 1097w,
925w, 877s, 648s, 344s, 285m. 1H NMR (300 K,
CDCl3): 2.0(s). LM (10−3 mol dm−3 MeNO2)=224
4. Conclusions
This study has shown that yttrium halides (X=Cl,
Br or I) form complexes with phosphine oxides in ratios
varying from 1:6 through 1:3 (although not all types
form with each ligand), and there are similar complexes
with R3AsO. Only certain of these complexes have been
isolated in the solid state. Solution studies have shown
that often a mixture of species is present in equilibrium,
the relative amounts being easily varied by addition of
R3EO. In spite of this, it is usually possible to crys-
tallise a single pure species from these solutions. Con-
trary to the literature reports [9–11,14] and in contrast
to the nitrate systems [7,8] all the halide complexes
contain six-coordinate pseudo-octahedral yttrium. Flux-
ionality in solution was observed in the nitrate systems
[7], but the NMR spectra of [YX(Ph3PO)5]2+ cations
show these are not fluxional. Fluxionality is relatively
rare in six-coordinate species (except metal hydrides)
and although the symmetry is too high in the cases of
the other complexes to provide evidence one way or the
other, it seems likely that all the halide complexes are
stereochemically rigid in solution.
V−1 cm2 mol−1
.
3.19. [YCl2(dppmO2)2]Cl
To a solution of YCl3·6H2O (0.076 g, 0.25 mmol) in
boiling EtOH (5 cm3) an ethanolic solution (10 cm3) of
dppmO2 (0.10 g, 0.25 mmol) was added, resulting in an
immediate white precipitate. The mixture was left to
stand for 1 h, the precipitate filtered off and dried in
vacuo. Yield: 0.06 g, 47%. Anal. Found: C, 57.9; H, 4.4.
Calc. for C50H44Cl3P4O4Y: C, 58.4; H, 4.3%. IR (cm−1
)
(CsI disc): 3042w, 1437m, 1410s, 1368m, 1167s (PO),
1120m, 1071w, 997w, 843s, 790s, 742m, 692m, 572w. 1H
NMR (300 K, CDCl3): 2.2 (s), 7.2–7.8 (m). LM (10−3
mol dm−3 CH2Cl2)=21 V−1 cm2 mol−1
.
3.20. [YCl2(ppO2)2]Cl
5. Supplementary material
Was made similarly to the above. Yield: 55%. Anal.
Found: C, 62.9; H, 4.3. Calc. for C60H48Cl3P4O4Y: C,
62.6; H, 4.2%. IR (cm−1) (CsI disc): 2960w, 1439m,
1410s, 1359m, 1171br, s (PO), 1121m, 1073w, 1005w,
Crystallographic data for the structures have been
deposited with the Cambridge Crystallographic Data

454
N.J. Hill et al. / Polyhedron 21 (2002) 445–455
Table 5
Crystallographic details a
Compound
[Y(Me3PO)6]Br3
[YCl2(Ph3PO)4]Cl·2.5EtOH·H2O
[YBr2(Ph3PO)4]PF6·Et2O
Molecular formula
Mr
Temperature (K)
Crystal system
Space group
C18H54Br3O6P6Y
881.08
100
monoclinic
C2/c (no. 15)
17.5730(9)
16.9269(9)
12.5446(7)
C72H60Cl3O4P4Y+C5H17O3.5
1441.53
150
monoclinic
P21/c (no. 14)
14.3599(3)
C72H60Br2F6O4P5Y+C4H10O
1580.96
150
triclinic
(
P1 (no. 2)
,
a (A)
13.1913(1)
14.9556(2)
18.1360(2)
98.1110(4)
94.1310(4)
96.2750(8)
3506.99(6)
2
,
b (A)
17.5316(4)
29.1891(7)
,
c (A)
h (°)
i (°)
k (°)
95.304(3)
97.748(1)
3
,
U (A )
Z
3715.5(3)
4
50.81
0.99
7281.3(3)
4
10.52
1.02
v (cm−1
S
)
21.57
2.09
F(000)/e
1776
2996
1608
Total no. of observations
No. of unique observations (Rint
Max/min transmission
18 530
54 736
49 343
)
3787 (0.166)
0.788/0.694
3787
13067 (0.099)
0.875/0.743
13067
14107 (0.087)
0.864/0.760
9456 (I\2|(I))
856
−1.58–2.33
0.079 (9456 reflections)
No. of data in refinement
No. of parameters
Residual electron density (e A
156
847
−3
,
)
−0.78–0.84
0.062 (2098 reflections)
0.144
−0.58–0.57
0.068 (6746 reflections)
0.166
R [Fo\4|(Fo)]
R (all data)
wR2 (all data)
wR [Fo\4|(Fo)]
0.152
0.175
0.086
[R=ꢀ ꢁꢁFoꢁ−ꢁFcꢁꢁ/ꢀ ꢁFoꢁ; wR2=[ꢀ w(Fo2−Fc2)2/ꢀ wFo4]1/2; wR=[ꢀ w(Fo−Fc)2/ꢀ wFo2]1/2].
a
,
Common data: Mo Ka (u=0.71073 A).
(b) Y.H. Jang, M. Blanco, S. Dasgupta, D.A. Keire, J.E. Shively,
W.A. Goddard, J. Am. Chem. Soc. 121 (1999) 6142 and refer-
ences therein.
Centre (CCDC) and given numbers 173577–79 for
compounds [YCl2(Ph3PO)4]Cl, [YBr2(Ph3PO)4]PF6,
[Y(Me3PO)6]Br3, respectively. Copies of the data 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).
[6] J. Mason (Ed.), Multinuclear NMR, Plenum, New York, 1987.
[7] L. Deakin, W. Levason, M.C. Popham, G. Reid, M. Webster, J.
Chem. Soc., Dalton Trans. (2000) 2439.
[8] W. Levason, B. Patel, M.C. Popham, G. Reid, M. Webster,
Polyhedron 20 (2001) 2711.
[9] T.S. Lobana, in: F.R. Hartley (Ed.), The Chemistry of
Organophosphorus Compounds, vol. 2, Wiley, New York, 1992,
p. 409.
[10] E. Giesbrecht, Pure Appl. Chem. 51 (1979) 925.
[11] D.R. Cousins, F.A. Hart, J. Inorg. Nucl. Chem. 30 (1968) 3009.
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Acknowledgements
We thank EPSRC for support and Professor M.B.
Hursthouse for access to the Nonius–Kappa CCD
diffractometer.
[14] H. Gehrke Jr., R. De Jong, Proc. S. Dak. Acad. Sci. 47 (1968)
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[15] An extreme case is Ref. [11] which although entitled ‘Complexes
of yttrium and lanthanide chlorides and thiocyanates with
triphenylarsine oxide and triphenylphosphine oxide’ contains no
further mention of yttrium chloride complexes, only those of Sm
and Nd.
[16] B. Neumu¨ller, R.M. Ko¨cker, K. Dehnicke, Z. Krystallogr. 209
(1994) 90.
[17] I.R. Beattie, T. Gilson, K. Livingston, V. Fawcett, G.A. Ozin, J.
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