Synthesis and structural characterisation of lanthanide and actinide phosphaorganometallic complexes derived from the 3,5-di-tert-butyl-1,2,4-triphospholyl ring anion, P3C2But-2: Crystal and molecular structures

Article abstract of DOI:10.1016/j.jorganchem.2008.03.030

Full title. Synthesis and structural characterisation of lanthanide and actinide phosphaorganometallic complexes derived from the 3,5-di-tert-butyl-1,2,4-triphospholyl ring anion, P₃C₂Bu^t-₂: Crystal and molecula

Full text of DOI:10.1016/j.jorganchem.2008.03.030

Journal of Organometallic Chemistry 693 (2008) 2287–2292
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Synthesis and structural characterisation of lanthanide and actinide
phosphaorganometallic complexes derived from the
3,5-di-tert-butyl-1,2,4-triphospholyl ring anion, P3C2But2ꢀ : Crystal and
molecular structures of [M(g5-P3C2But2)2(g2-P3C2But2)] (M = Sc, Y, Tm, and U)
*
Guy K.B. Clentsmith, F. Geoffrey N. Cloke , Matthew D. Francis, John R. Hanks, Peter B. Hitchcock,
*
John F. Nixon
Chemistry Department, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QJ, UK
a r t i c l e i n f o
a b s t r a c t
Treatment of MI3 (M = Sc, Y, Tm, and U) with three equivalents of KP3C2But2 in refluxing toluene led to the
corresponding monomeric, formally eight coordinate, complexes [M(g5-P3C2But2)2(g2-P3C2Bu2t )] in mod-
erate yields. In the solid state the complexes, which are all iso-structural, display an interesting assembly
of ligands comprising of one g2-(bent) and two g5-ligated triphospholyl rings. NMR studies indicate that
the complexes are fluxional in solution.
Article history:
Received 12 February 2008
Received in revised form 13 March 2008
Accepted 23 March 2008
Available online 1 April 2008
Ó 2008 Elsevier B.V. All rights reserved.
Keywords:
Fluxional
Triphosphacyclopentadienyl
Scandium
Yttrium
Thulium
Uranium
1. Introduction
Previously, we have used the aromatic ring anion 3,5-diter-
tiarybutyl-1,2,4-triphospholyl, P3C2Butꢀ extensively for the syn-
2
Cyclopentadienyl derivatives of Group 3 elements (including
scandium, yttrium, lanthanum and the lanthanides and actinides)
have been extensively studied [1]. More recently the cyclopentadi-
enyl ring system has been modified by the replacement of one or
more ring carbon atoms by Group 15 elements to afford hetero-
cyclopentadienyl complexes of these Group 3 elements. Typically
pyrollyl, phospholyl and arsolyl ring systems involving one hetero-
atom; pyrazolyl rings involving two heteroatoms and 1,2,4-tri-
phospholyl and 1,2,4-stibadiphospholyl rings containing three
heteroatoms have been employed. A variety of novel bonding
modes (in addition to the expected g5-ligation) have been estab-
lished for these hetero-cyclopentadienyl systems.
thesis of sandwich and half-sandwich complexes of several
transition metals (e.g. Sc [3], Ti [4,5], V [6], Cr [17], Mn [18], Fe
[7–13], Co [19], Ni [21–25], Ru [13–16], and Rh [16,20]) and main
group elements (e.g. Ga [26], In [27–29], Tl [26], Sr [30], and Pb
[31]). We have recently briefly reported [32] the synthesis of the
first structurally characterised scandocene, ‘‘[Sc(P3C2But2)2]” by
potassium graphite reduction of the corresponding Sc(III) complex.
Unexpectedly, this ‘‘hexaphosphascandocene” has an unprece-
dented dimeric structure in the solid state and is perhaps best re-
garded as a mixed-valence compound containing both Sc(I) and
Sc(III) centres.
We now describe the extension of this work to the synthesis and
structural characterisation of three other related trivalent metal
1,2,4-triphospholyl compounds of formula [M(P3C2But2)3] (M = Y,
Tm, U) drawn from both the lanthanide and actinide series, as well
as fuller details of the Sc(III) compound.
Thus, mono-substituted rings can ligate in both an g1-(planar or
bent) and l-g5-g1 fashion, while the proximity of two heteroatoms
in the 1,2,4-triphospholyl and 1,2,4-stibadiphospholyl rings offers
the possibility for other coordination modes such as g2-(planar
or bent), as well as l-g2- and l-g1-ligation (see Scheme 1).
The field of Group 3 metal-hetero-cyclopentadienyl complexes
has been comprehensively reviewed by Nief [2].
2. Results and discussion
Treatment of the 1,2,4-triphospholyl anion, P3C2Butꢀ (as its
2
base free potassium salt), with MI3 (M = Sc, Y, Tm, and U) in reflux-
ing toluene leads to the corresponding heteroleptic tris-1,2,4-tri-
* Corresponding authors.
E-mail address: j.Nixon@sussex.ac.uk (J.F. Nixon).
0022-328X/$ - see front matter Ó 2008 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2008.03.030

2288
G.K.B. Clentsmith et al. / Journal of Organometallic Chemistry 693 (2008) 2287–2292
Table 1
M
Crystallographic data for the complexes [M(g5-P3C2 But2)2(g2-P3C2But2)] (1–4)
E
E
M
E
Scandium
30H54P9Sc (1)
738.4
Monoclinic
Yttrium
Thulium
Uranium
Formula
M
Crystal
system
Space
group
C
C30H54P9Y (2) C30H54P9Tm (3)
782.37
Monoclinic
C30H54P9U (4)
931.49
Monoclinic
M
862.39
Monoclinic
η1− planar or bent
η5−
P21/c (no. 14)
P21/c (no. 14) P21/c (no. 14)
P21/c (no. 14)
M
E
M
E
a (Å)
b (Å)
c (Å)
a (°)
b (°)
c (°)
11.066(2)
16.014(2)
22.193(3)
90
102.99(2)
90
3832(1)
1.26
4
11.062(2)
16.105(5)
22.430(4)
90
102.95(2)
90
3894.3(16)
1.33
4
11.0942(6)
16.1459(12)
22.4184(13)
90
102.938(3)
90
3913.8(4)
1.46
4
11.0720(3)
16.2085(5)
22.5898(6)
90
103.282(2)
90
3945.56(19)
1.57
4
M
M
μ:η1−
μ:η5η1−
V (Å3)
D (g cmꢀ3
Z
M
E
M
M
)
M
E
M
E
M
E
E
E
E
E
F(000)
1560
0.59
1632
1.89
1752
2.65
1844
4.50
l (mmꢀ1
)
μ:η1−
μ:η2−
η2− planar or bent
Crystal
size (mm)
Tmin,max
Reflections
collected
Independent 5315 (0.0555)
(Rint
Reflections
I > 2rI
R1I > 2rI
wR2I > 2rI
R1 all data
wR2 all data 0.184
0.2 ꢁ 0.2 ꢁ 0.05 0.2 ꢁ 0.1 ꢁ 0.1 0.1 ꢁ 0.05 ꢁ 0.02 0.2 ꢁ 0.05 ꢁ
0.05
0.568, 0.750
39385
0.82, 1.00
5622
0.80, 1.00
7196
0.832, 0.912
18484
( E = P, As ; and in some cases Sb)
Scheme 1.
6828 (0.062)
3692
6831 (0.081)
4154
6925 (0.1047)
5109
)
2929
phospholyl metal (III) complexes M(P3C2But2)3 1 M = Sc, 2 M = Y, 3
M = Tm, 4 M = U, in moderate yields (Eq. (1)).
The complexes were characterised by elemental analysis, multi-
nuclear NMR spectroscopy and mass spectrometry and their solid-
state structures were confirmed by single crystal X-ray diffraction
studies. (vide infra).
0.074
0.150
0.151
0.077
0.144
0.164
0.179
0.058
0.119
0.116
0.141
0.046
0.092
0.073
0.103
t
MI3 þ 3KP3C2But ! MðP3C2Bu Þ þ 3KI
2
2
3
ð1Þ
1 M ¼ Sc; 2 M ¼ Y; 3 M ¼ Tm; 4 M ¼ U
2.1. Structural studies
Single crystal X-ray diffraction studies were carried out on com-
plexes 1–4 and the compounds were all found to be monomeric
and iso-structural. Crystallographic data for 1–4 are summarised
in Table 1. The molecular structure of each compound consists of
a formally eight coordinate metal atom which is ligated to one
1,2,4-triphospholyl ring in an g2-(bent) fashion and to two 1,2,4-
triphospholyl rings in an g5-coordination mode as shown below.
MI3 + 3KP3C2But2
M(P3C2But2)3 + 3 KI
1 M = Sc, 2 M = Y, 3 M = Tm, 4 M = U
The molecular structures of compounds 1–4 are shown in Figs.
1–4 together with important bond length and bond angle informa-
tion in Table 2. In all four complexes the rings are approximately
planar, with the tertiary butyl groups orientated so as to minimise
inter-ring interactions. There is very little variation in ring geome-
try within the three P3C2But2 rings regardless of their mode of
coordination nor is there significant variation in internal ring
geometry with that of K or Mg salts of the free anionic ring [33,34].
The unusual g2-(bent) bonding of one of the P3C2But2 rings ob-
served in complexes 1–4 is of interest and is similar to that re-
ported by Deacon et al. [35] for both the triphospholyl
compound [Sm(g5-C5Me5)2(g2- P3C2But2)THF] and the stiba-
diphospholyl salt [Li(THF)4][Yb(g5-P2SbC2But2)2(g2-P2SbC2But2)].
These authors attributed the structural differences between the tri-
phospholyl and stibadiphospholyl complexes and the correspond-
ing Ph2(pyrazolyl) compounds (which involves largely r-ring
bonding) to the increasingly diffuse nature of the lone pairs of
the heavier hetero-atoms in the sequence N, P, Sb which makes
Fig. 1. Molecular structure of 1 (Me groups omitted for clarity; ellipsoids at 50%
probability). Selected bond lengths (Å) and angles (°) Sc–M(1) 2.326(9), Sc–M(2)
2.371(9), Sc–C(1) 2.743(9), Sc–C(2) 2.731(9), Sc–C(21) 2.822(8), Sc–C(22) 2.790(8),
Sc–P(1) 2.813(3), Sc–P(2) 2.806(3), Sc–P(3) 2.870(3), Sc–P(4) 2.762(3), Sc–P(5)
2.796(3), Sc–P(7) 2.793(3), Sc–P(8) 2.773(3), Sc–P(9) 2.773(3), P(1)–C(1) 1.754(8),
P(1)–P(2) 2.117(4), P(2)–C(2) 1.751(8), P(3)–C(1) 1.744(8), M(1)–Sc–M(2) 140.2(2),
M(1)–Sc–P(4) 114.10(8), M(1)–Sc–P(5) 112.75(7), M(2)–Sc–P(4) 102.70(8), M(2)–
Sc–P(5) 103.85(7), C(1)–P(1)–P(2) 98.6(3), C(2)–P(2)–P(1) 98.8(3), C(2)–P(3)–C(1)
98.9(4), P(1)–C(1)–P(3) 121.8(5), P(2)–C(2)–P(3) 121.9(5). (M(1) and M(2) refer to
the centroids of the two g5-ligated rings).
the latter less suitable for electrostatic interactions with the hard
Ln3+ ions, thereby causing a steady change from r- via r/p to p
interactions.
Interestingly, the analogous tris(cyclopentadienyl) lanthanide
complexes exhibit one of three structural motifs (each of which is
oligomeric or polymeric) so as to maximise the coordination num-

G.K.B. Clentsmith et al. / Journal of Organometallic Chemistry 693 (2008) 2287–2292
2289
Table 2
Bond lengths (Å) and angles (°) for M(P3C2tBu2)3 (1–4) (M = Sc, Y, Tm, and U)
Bond/angle
Sc
Y
Tm
U
M–M(1)
M–M(2)
M–P(4)
2.326(9)
2.371(9)
2.762(3)
2.796(3)
2.099(3)
2.117(4)
1.754(8)
1.751(8)
1.744(8)
1.740(8)
2.478(8)
2.508(8)
2.884(2)
2.912(2)
2.111(3)
2.120(4)
1.759(9)
1.766(8)
1.760(8)
1.743(9)
2.488(9)
2.451(9)
2.853(2)
2.891(2)
2.118(3)
2.116(3)
1.765(8)
1.779(8)
1.751(8)
1.742(9)
2.577(7)
2.580(7)
2.9675(19)
2.9950(18)
2.118(3)
2.126(3)
1.761(7)
1.765(7)
1.754(8)
1.764(7)
M–P(5)
P(4)–P(5)
P(1)–P(2)
P(1)–C(1)
P(2)–C(2)
P(3)–C(1)
P(3)–C(2)
M(1)–M–M(2)
C(1)–P(1)–P(2)
C(2)–P(2)–P(1)
C(1)–P(3)–C(2)
P(1)–C(1)–P(3)
P(2)–C(2)–P(3)
140.2(2)
98.6(3)
98.8(3)
98.9(4)
121.8(5)
121.9(5)
139.4(2)
99.3(3)
99.0(3)
99.8(4)
120.7(5)
121.1(5)
139.49(2)
99.0(3)
98.8(3)
99.5(4)
121.4(5)
121.2(4)
136.7(2)
98.9(3)
99.5(3)
99.8(3)
121.3(4)
120.4(4)
Atom numbering is based on that of Sc(P3C2tBu2)3). (M(1) and M(2) refer to the
centroids of the two g5-ligated rings).
Fig. 2. Molecular structure of Y(P3C2tBu2)3 (2).
ber of the central metal atom. The use of cyclopentadienyl ligands
with bulky substituents such as (1,3-(TMS)C5H3) has facilitated
the isolation and characterisation of monomeric tris(cyclopentadi-
enyl) complexes of cerium, samarium and thorium [36–38]. How-
t
ever, these compounds differ from the M(P3C2 Bu2)3 compounds
reported above, in that all the three (1,3-(TMS)C5H3) rings are g5-
coordinated and are equally disposed around the metal centre.
t
The P3C2 Bu2 and 1,3-(TMS)(C5H3) ring systems bear substituents
t
of similar steric bulk and the longer P–C bonds make the P3C2 Bu2
rings more sterically demanding, but it is difficult to conclude
whether steric or electronic effects play the most significant role
in determining the structures of compounds 1–4.
Figs. 2–4 show the molecular structures of complexes [M(g5-
P3C2But2)2(g2-P3C2But2)] (2–4) (M = Y, Tm, and U).
A comparison of selected bond lengths and bond angles for all
t
the [M(P3C2 Bu2)3] metal complexes 1–4 is presented in Table 2.
The similarity for a series of compounds containing metals of con-
siderably different sizes strongly suggests that the ligand system is
the dominating factor in determining structure.
2.2. 31P NMR studies
Fig. 3. Molecular structure of Tm(P3C2tBu2)3 (3) (Me groups are omitted for clarity;
ellipsoids at 50% probability).
32
As previously mentioned in our preliminary publication,
the
31P{1H} NMR spectrum of a solution of the scandium(III) tris-
1,2,4-triphospholyl complex 1 consists of two symmetric but
highly complex multiplets at 296.2 and 265.0 ppm in the ratio of
1:2. The presence of only two resonances suggests that on the
NMR timescale the three 1,2,4-triphospholyl rings are rapidly in-
ter-converting in solution in contrast to the solid-state structure
discussed earlier, in which two distinct bonding modes are ob-
served for the 1,2,4-triphospholyl ligands. The complexity of the
multiplets in the 31P{1H} NMR spectrum suggests that there is sig-
nificant inter-ring coupling which causes the resonances to deviate
from a simple AX2 spin system and it was successfully simulated as
an AA0A00X2X0 X00 spin system involving coupling constants JAX
¼
2
2
0
00
0
0
00
00
A0X0
AX
X
X
00X0
J
¼ ꢀ50:7 Hz; J
¼ JAX ¼ JA ¼ JA X ¼ J A ¼ JA ¼ þ21:5 Hz;
0
00
0
00
0
00
0 00
JXX ¼ JXX ¼ JX X ¼ ꢂ5:0 Hz; JAA ¼ JAA ¼ JA A ¼ 0 Hz (signs of the
couplings are relative, not absolute).
A comparison of the
simulated and experimental spectra is illustrated in Fig. 5 and
shows excellent agreement between the two.
The corresponding 31P{1H} NMR spectrum for the yttrium com-
plex 2 is significantly different from that of 1. At room temperature
two broad resonances are observed at 289.9 and 263.9 ppm in the
ratio of 1:2. As the sample is warmed, the signals gradually begin
to resolve somewhat although they remain slightly broadened
Fig. 4. Molecular structure of U(P3C2tBu2)3 (4).

2290
G.K.B. Clentsmith et al. / Journal of Organometallic Chemistry 693 (2008) 2287–2292
Fig. 5. Experimental and simulated 31P{1H} NMR spectrum of [Sc(g5-P3C2But2)2(g2-P3C2But2)] (1).
and at 70 °C the higher field signal becomes a doublet from which a
typical JPP coupling of 49.3 Hz can be measured. At this tempera-
ual 1H resonances of the solvent or to external 85% H3PO4 (d = 0.00,
31P{1H} NMR). EI mass spectra were recorded on a VG Autospec
instrument at 70 eV. Microanalyses were conducted by Labor
Pascher, Remagen, Germany or by the Canadian Microanalytical
Services Ltd. The anhydrous metal iodides UI3, YI3 and TmI3 were
prepared according to the general method described by Corbett
[39], in which the metal (in the form of turnings) is heated with
an excess of HgI2 in a sealed tube at ca 320 °C.
2
ture the lower field resonance also begins to show evidence of res-
olution into the expected doublet but the coupling cannot be
clearly deduced from this signal. The absence of any other cou-
plings in this system suggests that, unlike the scandium case, there
is smaller coupling between rings in the yttrium complex, perhaps
because the larger size of yttrium reduces any significant ‘through-
space’ coupling. The 31P{1H} NMR spectra of 3 (4f12) and 4 (5f3)
were both very broad as expected.
3.2. Synthesis of uranium triiodide
Uranium turnings were treated with concentrated nitric acid
then washed with de-ionised water to give them a silver metallic
finish. The turnings were then washed with methanol followed by
acetone and dried in vacuo. A thick-walled ampoule with two con-
striction points was then charged with the dry uranium turnings
(2.28 g, 9.58 ꢁ 10ꢀ3 mol) and HgI2 (8.71 g, 19.16 ꢁ 10ꢀ3 mol). The
ampoule was then evacuated to 10ꢀ6 mbar, sealed under vacuum
at the first constriction point and fully immersed vertically in a tube
furnace at 315 °C for 3 days. The furnace was then placed in a hor-
izontal position with the empty end of the ampoule protruding
from the furnace to allow Hg and unreacted HgI2 to condense and
sublime out, respectively. This was left for a further 2 days at
315 °C. The sealed tube was taken into the glove box and snapped
3. Experimental
3.1. General procedures
Since all the compounds described are highly air and moisture
sensitive, manipulations were carried out under an atmosphere
of high purity argon using conventional Schlenk or glove box tech-
niques. The solvents toluene, mesitylene, hexane and pentane were
refluxed over Na/K alloy for at least 36 h and were distilled and
freeze-thaw degassed before use. NMR solvents were refluxed over
potassium and were vacuum distilled into greaseless Schlenk tubes
and stored under argon. NMR spectra were recorded on a Bruker
AMX-500 or DPX-300 instrument and were referenced to the resid-

G.K.B. Clentsmith et al. / Journal of Organometallic Chemistry 693 (2008) 2287–2292
2291
at the constriction; the UI3 was collected and ground up with a mor-
tar and pestle. The purple powder was transferred to a tantalum
boat, which was placed in a sublimation tube. The tube was evacu-
ated to 10ꢀ6 mbar and heated in a furnace to 200 °C for 2 h, 300 °C
for 1 h and 400 °C for 30 min to remove any remaining Hg and HgI2.
The purple solid in the tantalum boat was then collected and stored
under dinitrogen in the glovebox (5.63 g, 9.09 mmol, 95% yield). YI3
and TmI3 were prepared in a similar fashion.
ated and the mixture heated to 110 °C for 48 h during which time it
became a dark brown color. The reaction mixture was filtered to
remove salts and the filtrate evaporated in vacuo to afford a brown
solid. Sublimation at 220 °C (10ꢀ6 mm Hg) afforded pure
[U(g5-P3C2But2)2(g2-P3C2But2)] as a dark brown crystalline solid
(0.420 g, 36%). Alternatively the crude product could be purified
by recrystallisation from pentane at ꢀ40 °C. 1H (300 MHz, C6D6)
d ꢀ8.54 (s, 54H, But). 31P{1H} (121 MHz; C6D6): d 691.5 (broad,
W1/2 ꢃ 200 Hz). MS (70 eV, EI) m/z (%): 931 (27) [M]+, 700 (100)
[MꢀP3C2But2]+. Anal. Calc. for C30H54P9U (931.5): C, 38.68; H,
5.84. Found: C, 38.69; H, 5.72%. Single crystals suitable for X-ray
analysis were grown from a slowly cooled (to ꢀ40 °C) pentane
solution.
3.3. Synthesis of [Sc(g5-P3C2But2)2(g2-P3C2But2)] (1)
ScI3 (0.254 g, 0.597 mmol) and KP3C2But2 (0.5 g, 1.85 mmol)
were placed in an ampoule and toluene (40 mL) was added. The am-
poule was evacuated, the mixture sonicated for ten minutes and
then heated at 110 °C for 40 h during which time a deep red color
developed. The reaction mixture was filtered to remove salts and
the solvent removed in vacuo to afford the crude product as a red so-
lid. This was recrystallised at ꢀ40 °C from hexane yielding pure
[Sc(g5-P3C2But2)2(g2-P3C2But2)] as a dark red crystalline solid
(0.240 g, 54 %). 1H (300 MHz; C7D8): d 1.67 (s, 54H, But). 31P{1H}
(121 MHz; C7D8): d 296.2 (m, CPC), 265.0 (m, CPPC); both multiplets
are complex, see Section 2 for analysis of the couplings and a spectral
simulation. MS (70 eV, EI) m/z (%): 738 (35) [M]+, 681 (21) [MꢀBut]+,
57 (100) [But]+. Anal. Calc. for C30H54P9Sc (738.4): C, 48.79; H, 7.37.
Found: C, 48.54; H, 7.21%. Single crystals suitable for X-ray analysis
were grown from a slowly cooled (to ꢀ40 °C) hexane solution.
3.7. Structure determinations
X-ray quality crystals of all complexes were grown from slowly
cooled saturated hexane or pentane solutions. Reflection data were
measured on a Kappa CCD area detector at 172(3) K using Mo Ka
radiation (k = 0.71073 Å). The structure of the yttrium complex is
disordered 0.96:0.04 about a mirror plane perpendicular to the
coordination plane going through Y and P(6). Only the P atoms of
the lower occupancy orientation were located and were refined
with a common isotropic thermal parameter. One t-butyl group
of the major orientation was disordered in a 50:50 ratio. Non-H
atoms were anisotropic, except for the disordered t-butyl group
and the alternative P atom sites. H’s were included in riding mode
with Uiso(H) equal to 1.5Ueq(C). In the thulium complex there is a
very low occupancy (0.02) alternative mirror image ligand
arrangement, sharing a common P(4) site, for which only the P
atom sites could be located. The C(8), C(9) and C(10) carbon atoms
of the methyl group were disordered equally over two sets of posi-
tions which were refined isotropic and with distance constraints.
3.4. Synthesis of [Y(g5-P3C2But2)2(g2-P3C2But2)] (2)
YI3 (1 mmol) and KP3C2But2 (3 mmol) were placed in an am-
poule and toluene (50 mL) was added. The ampoule was evacuated
and the mixture heated at 110 °C for 48 h during which time a
deep red color formed. The reaction mixture was filtered to remove
salts and the filtrate evaporated in vacuo to afford the crude prod-
uct as a dark red solid. This was recrystallised from hexane at
ꢀ85 °C to afford pure [Y(g5-P3C2But2)2(g2-P3C2But2)] as a dark
red crystalline solid (0.220 g, 28%). 31P{1H} (343 K, 121 MHz,
Acknowledgements
We thank the EPSRC for financial support in the form of a stu-
dentship (for J.R.H.) and PDRA (for for this work) and acknowledge
the late Dr. Anthony G. Avent for simulation of the 31P NMR spec-
trum of 1.
2
C6D6) d 291.4 (m, CPC), 264.9 (d, JPP= 49.3 Hz, CPPC). MS (70 eV,
EI) m/z (%) 782 (12) [M]+, 552 (100) [MꢀP3C2But2]+. Anal. Calc.
for C30H54P9Y (782): C, 46.05; H, 6.96. Found: C, 46.32; H, 6.96%.
Single crystals suitable for X-ray analysis were grown from a
slowly cooled (to ꢀ40 °C) pentane solution.
Appendix A. Supplementary material
3.5. Synthesis of [Tm(g5-P3C2But2)2(g2-P3C2But2)] (3)
Supplementary data associated with this article can be found, in
the online version, at doi:10.1016/j.jorganchem.2008.03.030.
TmI3 (0.328 g, 0.598 mmol) and KP3C2But2 (0.5 g, 1.85 mmol)
were placed in an ampoule and mesitylene (30 mL) was added.
The ampoule was evacuated, the mixture sonicated for 10 min
and then heated at 160 °C for 48 h during which time an orange
color developed. The mixture was then filtered to remove salts
and the filtrate evaporated in vacuo to yield the crude product as
a dark orange solid. This was recrystallised from hexane at
ꢀ40 °C to afford pure [Tm(g5-P3C2But2)2(g2-P3C2But2)] as an or-
ange crystalline solid (0.110 g, 21%). MS (70 eV, EI) m/z (%): 862
(12) [M]+, 631 (100) [MꢀP3C2But2]+. Anal. Calc. for C30H54P9Tm
(862): C, 41.80; H, 6.31. Found: C, 41.09; H, 6.93%.
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