Synthesis and coordinating properties of the facultative Sb2O- and As2O-donor ligands O{(CH2)2ER2}2 (E = Sb or As; R = Ph or Me)

Article abstract of DOI:10.1016/j.jorganchem.2007.08.034

The new mixed Sb₂O-donor ligands O{(CH₂)₂SbR₂}₂ (R = Ph, 1; R = Me, 2) with flexible backbones have been prepared in good yields as air-sensitive oils from reaction of NaSbR₂ with 0.5 mol e

Full text of DOI:10.1016/j.jorganchem.2007.08.034

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Journal of Organometallic Chemistry 692 (2007) 5589–5597
www.elsevier.com/locate/jorganchem
Synthesis and coordinating properties of the facultative Sb2O-
and As2O-donor ligands O{(CH2)2ER2}2 (E = Sb or As; R = Ph or Me)
*
Martin F. Davis, Marek Jura, William Levason, Gillian Reid , Michael Webster
School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, UK
Received 10 July 2007; received in revised form 21 August 2007; accepted 26 August 2007
Available online 4 September 2007
Abstract
The new mixed Sb2O-donor ligands O{(CH2)2SbR2}2 (R = Ph, 1; R = Me, 2) with flexible backbones have been prepared in good
yields as air-sensitive oils from reaction of NaSbR2 with 0.5 mol equivalents of O(CH2CH2Br)2 in thf solution. The As2O-donor ana-
logues, O{(CH2)2AsR2}2 (R = Ph, 3; R = Me, 4) were obtained similarly from LiAsPh2 or NaAsMe2, respectively and O(CH2CH2Br)2,
although ligand 4 appears to be considerably less stable with respect to C–O bond fission under some conditions than the other ligands.
ꢀ
ꢀ
Using O(CH2CH2Cl)2 leads only to partial substitution by the SbPh2 or AsPh2 nucleophile. These ligands behave as bidentate che-
lating Sb2- or As2-donors in the distorted tetrahedral [M(L–L)2]BF4 (M = Cu or Ag; L–L = 1–4) on the basis of solution H and 63Cu
1
NMR spectroscopic studies, mass spectrometry and microanalyses. Crystal structures of three representative examples with Cu(I) and
Ag(I) confirm the distorted tetrahedral Sb4 or As4 coordination at the metal and allow comparisons of geometric parameters. The
crystallographic identification of an unexpected Cu(I)–Cu(I) complex, [Cu2{Me2As(CH2)2OH}3](BF4)2, obtained as a by-product via
C–O bond fission within ligand 4 is also reported. The distorted octahedral [RhCl2(L–L)2]Cl and the distorted square planar cis-
[PtCl2(L–L)] (L–L = 1 or 2) are also described. The ether O atoms are not involved in coordination to the metal ion in any of the late
transition metal complexes isolated.
ꢀ 2007 Elsevier B.V. All rights reserved.
Keywords: Stibine; Arsine; X-ray structures; Copper; Silver
1. Introduction
cases of bridging neutral Group 15 ligands in rhodium car-
bene complexes of SbiPr3. Furthermore, entry into the
corresponding PiPr3 bridged species requires initial prepara-
tion of the bridged stibine species and then substitution of
SbR3 by PR3, reflecting profoundly different electronic
behaviours for the two. Work on the organometallic chem-
istry of platinum metal stibine complexes from the same
research group has also revealed markedly different prod-
ucts are obtained from these compared to those obtained
using phosphines. Our own work on Rh(I) stibine chemistry
has also identified significant differences in the chemistry of
distibines compared to their diphosphine analogues, e.g.,
reaction of [Rh(CO){Ph2Sb(CH2)3SbPh2}2]+ with HCl
gas leads to both oxidative addition and cleavage of Ph
groups from the stibine (the latter producing chelating
PhClSb(CH2)3SbClPh on Rh(III)) and the inability of excess
Ph2Sb(CH2)3SbPh2 to displace cod from [Rh(cod)Cl]2 [9].
Stibine ligand chemistry has been much less developed
compared to that of the lighter Group 15 donor analogues,
phosphines and arsines. This is probably mainly a conse-
quence of the weakness of the Sb–C bonds, the lack of read-
ily available Sb-containing precursor compounds and the
early (incorrect) perception that stibines behave the same
way as phosphines towards transition metals, but are poorer
ligands [1–3]. Recent work from Werner and co-workers [4–
6] and ourselves [7–10] has provided clear demonstrations of
important differences in the chemistry of stibines compared
to phosphines – for example, Werner has identified the first
*
Corresponding author. Tel.: +44 023 80593609; fax: +44 023
80593781.
E-mail address: gr@soton.ac.uk (G. Reid).
0022-328X/$ - see front matter ꢀ 2007 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2007.08.034

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M.F. Davis et al. / Journal of Organometallic Chemistry 692 (2007) 5589–5597
The latter is almost certainly associated with the reduced r-
donor properties of the stibine, and this has recently been
used to good effect in the catalytic polymerisation of styrene
[11] and norbornene insertion polymerisation [12] by SbPh3
complexes of nickel, in which the rapid and reversible Ni-
SbPh3 coordination is thought to be key.
glove box and during distillation and reaction with transi-
tion metal salts. The preparation of 4 gave variable yields
1
– in some cases the H and 13C{1H} NMR spectra showed
4 to be the only significant product, whereas in others addi-
tional resonances were evident. During distillation of 4
from this crude mixture a second, less volatile fraction
(74 ꢁC, 0.05 mmHg) was collected in addition to 4 (58 ꢁC,
0.05 mmHg). The NMR features of both fractions show
AsMe2, CH2As and CH2O resonances, with relative inte-
grals of 3:2:2, and while the Me and AsCH2 resonances
are nearly superimposed, that for CH2O is some 0.2 ppm
to low frequency of the CH2O resonance in 4. GCEI MS
of the by-product shows peaks at m/z = 150, consistent with
Me2As(CH2)2OH, apparently formed via C–O bond fission.
Dimethylene linkages are well known to be unstable with
respect to elimination of ethene [1,2], however, it is a little
surprising that compound 4 appears to be markedly less
stable than the other ligands in this study which also incor-
porate dimethylene linkages. We note that Ph2As(CH2)2-
AsPh2 is a well known stable compound, whereas
Me2As(CH2)2AsMe2 has only been obtained in very low
yield and has very little associated chemistry [16]. The
compound Me2As(CH2)2OH has been reported as a frag-
mentation product from Me2Si(OCH2CH2AsMe2)2 with
transition metal compounds and its reaction chemistry with
Group 6 carbonyls has been described, although no charac-
terisation data on the arsinoethanol itself have been
reported [17].
We have investigated a series of complexes of ligands 1–4
with late transition metal ions to probe the coordination
modes and to establish whether both the ether O and the
As/Sb donor atoms can coordinate simulataneously. Reac-
tion of ligands 1–3 (L–L) with [Cu(MeCN)4]BF4 in MeOH
using either a 1:1 or 2:1 ligand:Cu ratio yields only the bis-
ligand species [Cu(L–L)2]BF4 which were isolated as colour-
less crystalline solids. Confirmation of the 1:2 Cu:L–L ratio
follows from the electrospray MS data (which reveal the
main species to be [Cu(L–L)2]+ and [Cu(L–L)(MeCN)]+
for L–L = 1–3), 63Cu NMR spectroscopic measurements
and microanalyses. d(63Cu) = ꢀ229 and ꢀ194 ppm for the
Cu complexes of 1 and 2 respectively, and ꢀ139 for the
complex of 3. Copper-63 is quadrupolar with I = 3/2
(69%) and as a result of its moderately high quadrupole
moment (Q = ꢀ0.211 · 10ꢀ28 m2) resonances are typically
only observed for high symmetry Cu environments – in
the compounds studied here the chemical shifts are consis-
tent with approximately tetrahedral Sb4 and As4 donor
While a range of distibines have been reported (mostly
involving reaction of stibides, R2Sbꢀ with haloalkanes
[1–3] or more recently via reaction of R2SbCl with di-Grig-
nard reagents [3,7,8]), stibines with higher denticities are
very rare – the tripodal MeC(CH2SbPh2)3 being the sole
example of a tristibine [13], although there are a few exam-
ples of mixed donor Sb/O and Sb/N polydentates [15]. In the
course of our work towards the development of syntheti-
cally viable routes to polydentate and macrocyclic stibines,
we have investigated the preparations of the new, potentially
tridentate stibine-ether ligands O{(CH2)2SbR2}2 (1: R = Ph;
2: R = Me). The analogous arsine-ethers, O{(CH2)2AsR2}2
(3: R = Ph; 4: R = Me) have also been prepared to allow
comparison of the ligand properties with selected late tran-
sition metals. There is an early report of compound 3, but it
was only characterised as its NiI2 complex [14].
2. Results and discussion
The new Sb2O-donor ligands 1 and 2 are obtained in
good yield from reaction of NaSbR2 (R = Ph or Me) (them-
selves obtained by treatment of R2SbCl with Na in liquid
NH3 at ꢀ78 ꢁC) with 0.5 mol. equiv. of O(CH2CH2Br)2.
The a,x-dibromo precursor is necessary to allow complete
substitution (the corresponding O(CH2CH2Cl)2 leads only
to partial substitution especially by the Ph2Sbꢀ nucleo-
phile). Both 1 and 2 are light yellow air-sensitive (especially
2) oils, hence the compounds were stored and handled in a
glove box. 1H and 13C{1H} NMR spectroscopic data for 1
and 2 are fully in accord with the formulations, revealing
the two triplets expected for the linking CH2 groups, and
for 2, the SbMe2 groups significantly shielded as expected.
EIMS of 1 reveals a cluster of peaks at m/z = 624 consistent
with the parent ion, [M]+. As with previous work on new
organoantimony compounds, we have prepared and char-
acterised air stable Sb(V) or stibonium derivatives of 1
and 2 to confirm their identities. The tetrabromide deriva-
tive of 1 was obtained as a white solid by treatment with
2 mol. equiv. of Br2 in CH2Cl2. NMR spectroscopic studies
show a considerable high frequency shift for the CH2Sb
groups (d(1H) shifts from 2.06 to 4.36 ppm; d(13C) shifts
from 22.53 to 55.27 ppm), consistent with formal oxidation
from Sb(III) to Sb(V). The distibonium derivative of 2,
O{(CH2)2SbMe3I}2, was isolated as a white solid from reac-
tion of 2 with excess MeI in acetone solution and character-
ised by NMR spectroscopy, electrospray MS (MeCN) and
microanalysis. The analogous As2O-donor ligands 3 and 4
were obtained from O(CH2CH2Br)2 and LiAsPh2 (3) or
NaAsMe2 (4) and characterised similarly. While compound
3 appears to be stable, 4 is much less so and undergoes sig-
nificant degradation upon standing even under N2 in the
environments
respectively
(cf.
[Cu{Me2Sb(CH2)3-
SbMe2}2]+ d(63Cu) = ꢀ167, [Cu{o-C6H4(AsMe2)2}2]+-
d(63Cu) = ꢀ63) [18].
A similar reaction of 4 with
[Cu(MeCN)4]BF4 in MeOH solution did not yield
[Cu(4)2]BF4 cleanly, the solution changing from colourless
to green and back to colourless during work-up. Electro-
spray MS (MeCN) on the colourless solid isolated showed
peaks at m/z = 627, 386 and 345, consistent with
[Cu(4)2]+, [Cu(4)(MeCN)]+ and [Cu(4)]+. The 63Cu NMR
spectrum shows a broad resonance associated with the

M.F. Davis et al. / Journal of Organometallic Chemistry 692 (2007) 5589–5597
5591
pseudo-tetrahedral Cu(I) cation, [Cu(4)2]+ at ꢀ16 ppm,
2.348(3)–2.358(3) A, revealing
a
correlation between
˚
confirming the presence of this species in solution. How-
ever, the NMR solution also changed to pale green during
data acquisition, consistent with some sample degradation,
and a structure determination on crystals obtained upon
slow evaporation from a solution of the product in
MeOH/Et2O revealed an unexpected dinuclear Cu(I)–
Cu(I) complex incorporating the fragmented ligand
Me2As(CH2)2OH – see below.
increasing ligand steric demands and increased bond lengths
[18,19]. The lattice MeOH in [Cu(3)2]BF4 Æ MeOH is
involved in weak H-bonding interactions with the [BF4]ꢀ
anion, O3ꢁ ꢁ ꢁF2 = 2.97 A.
˚
Similar coordination is seen for the corresponding (light
sensitive) Ag(I) species [Ag(L–L)2]BF4 (L–L = 1–3)
(obtained from direct reaction of AgBF4 with L–L in
MeOH in a foil-wrapped flask to exclude light). Like the
Cu(I) complex of ligand 4 above, reaction of AgBF4 with
4 did not yield a tractable, pure sample of [Ag(4)2]+. Spec-
troscopic data confirm the presence of this product, how-
ever the product is unstable, blackening on standing even
in the dark, possibly also due to some C–O fission. The crys-
tal structures of [Ag(1)2]BF4 Æ CH2Cl2 (Fig. 2, Table 2) and
[Ag(3)2]BF4 Æ MeOH (Fig. 3, Table 3) which show discrete
monomeric cations with distorted tetrahedral Sb4 and As4
coordination, respectively at Ag(I) via two bidentate L–L
units, and with Ag–Sb and Ag–As bond distances in the
The geometry at the metal in the Cu(I) complexes,
[Cu(L–L)2]BF4, is confirmed from the crystal structure of
[Cu(3)2]BF4 Æ MeOH (Fig. 1, Table 1) which shows a dis-
torted tetrahedral coordination environment at Cu(I), with
the ligands behaving as bidentate As2-donors and with the
ether O atoms not interacting with the metal. The Cu–As
˚
bond distances lie in the range 2.4202(9)–2.4652(9) A
respectively, while the As–Cu–As angles within the chelate
rings are 106.36(3)ꢁ and 107.09(3)ꢁ. The bond distances
are shorter than those in [Cu(AsPh3)4]ClO4 2.493(2)–
˚
˚
˚
2.533(1) A, but significantly longer (by ca. 0.08 A)
ranges 2.7020(5)–2.7341(5) and 2.6143(9)–2.6376(9) A,
respectively. These compare very well with d(Ag–Sb) of
than those in [Cu(Ph2AsCH@CHAsPh2)2]+ d(Cu–As) =
C43
C43
C42
O2
C42
C44
C44
C45
O2
C41
C51
C41
C17
C45
C35
Sb4
C35
Ag1
As3
As4
As1
C51
C29
Sb3
C29
Cu1
C23
C1
Sb1
As2
Sb2
C15
C1
O1
C7
C23
C15
C17
C13
C13
O1
C16
C16
C14
C7
C14
Fig. 1. View of the structure of [Cu(3)2]+ with numbering scheme
adopted. Ellipsoids are drawn at the 50% probability level. H atoms and
the phenyl rings (except the ipso C atoms) are omitted for clarity.
Fig. 2. View of the structure of [Ag(1)2]+ with numbering scheme
adopted. Ellipsoids are drawn at the 50% probability level. H atoms and
the phenyl rings (except the ipso C atoms) are omitted for clarity.
Table 2
Table 1
˚
˚
Selected bond lengths (A) and angles (ꢁ) for [Ag(1)2]BF4 Æ CH2Cl2
Selected bond lengths (A) and angles (ꢁ) for [Cu(3)2]BF4 Æ MeOH
Ag1–Sb1
Ag1–Sb3
2.7268(5)
2.7020(5)
Ag1–Sb2
Ag1–Sb4
2.7341(5)
2.7194(5)
Cu1–As1
Cu1–As3
2.4212(9)
2.4202(9)
Cu1–As2
Cu1–As4
2.4223(9)
2.4652(9)
Sb3–Ag1–Sb4
Sb4–Ag1–Sb1
Sb4–Ag1–Sb2
103.55(2)
116.26(2)
109.30(2)
Sb3–Ag1–Sb1
Sb3–Ag1–Sb2
Sb1–Ag1–Sb2
107.49(2)
116.79(2)
103.95(2)
As3–Cu1–As1
As1–Cu1–As2
As1–Cu1–As4
110.64(3)
107.09(3)
108.09(3)
As3–Cu1–As2
As3–Cu1–As4
As2–Cu1–As4
107.65(3)
106.36(3)
117.00(3)

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M.F. Davis et al. / Journal of Organometallic Chemistry 692 (2007) 5589–5597
C43
C9
C42
C10
C44
C11
C41
O2
As3
C35
C12
C6
C45
C51
As3
O2
As4
Cu1
O3
Ag1
C8
C23
C29
As1
As2
Cu2
C1
As2
C7
C7
C16
C2
O1
As1
C13
C17
O1
C5
C4
C15
C1
C3
C14
Fig. 4. View of the structure of [Cu2{Me2As(CH2)2OH}3]2+ with num-
bering scheme adopted. Ellipsoids are drawn at the 50% probability level.
H atoms are omitted for clarity.
Fig. 3. View of the structure of [Ag(3)2]+ with numbering scheme
adopted. Ellipsoids are drawn at the 50% probability level. H atoms and
the phenyl rings (except the ipso C atoms) are omitted for clarity.
Table 4
Table 3
˚
Selected bond lengths (A) and angles (ꢁ) for [Cu2{Me2As(CH2)2OH}3]-
(BF4)2
˚
Selected bond lengths (A) and angles (ꢁ) for [Ag(3)2]BF4 Æ MeOH
Ag1–As1
Ag1–As3
2.6376(9)
2.6317(9)
Ag1–As2
Ag1–As4
2.6143(9)
2.6296(9)
Cu1–O2
2.058(6)
2.326(1)
2.343(1)
2.497(1)
Cu2–O3
Cu2–O1
Cu2–As2
Cu1ꢁ ꢁ ꢁAs2
O2–Cu1–As1
O2–Cu1ꢁ ꢁ ꢁCu2
As1–Cu1ꢁ ꢁ ꢁCu2
As3–Cu1ꢁ ꢁ ꢁAs2
O3–Cu2–O1
2.021(5)
2.116(6)
2.283(1)
2.934(1)
Cu1–As3
Cu1–As1
Cu1ꢁ ꢁ ꢁCu2
As2–Ag1–As4
As4–Ag1–As3
As4–Ag1–As1
95.67(3)
108.09(3)
111.63(3)
As2–Ag1–As3
As2–Ag1–As1
As3–Ag1–As1
118.83(3)
107.60(3)
113.65(3)
O2–Cu1–As3
116.77(18)
123.12(5)
91.58(5)
78.38(16)
111.67(5)
155.21(18)
98.21(16)
75.58(4)
110.87(19)
126.19(17)
83.99(5)
106.81(5)
87.8(2)
As3–Cu1–As1
As3–Cu1ꢁ ꢁ ꢁCu2
O2–Cu1ꢁ ꢁ ꢁAs2
As1–Cu1ꢁ ꢁ ꢁAs2
O3–Cu2–As2
˚
2.720(1)–2.730(1) A in [Ag(SbPh3)4]BF4 [20] and d(Ag–As)
of 2.649(2), 2.650(2) A in [Ag(AsPh3)4]ClO4 [19]. We note
˚
O1–Cu2–As2
O1–Cu2ꢁ ꢁ ꢁCu1
116.05(16)
122.14(17)
that the Sb–Ag–Sb angles within the chelates are ca. 4ꢁ
smaller than the corresponding As–Ag–As chelate angles.
The MeOH solvent mꢀolecule in [Ag(3)2]BF4 Æ MeOH is also
O3–Cu2ꢁ ꢁ ꢁCu1
As2–Cu2ꢁ ꢁ ꢁCu1
˚
H-bonded to the BF4 anion, O3ꢁ ꢁ ꢁF1 = 2.80 A.
The dimethylarsinoethanol ligands clearly result from
C–O fission in ligand 4 during the complexation reaction.
Although the hydroxyl H atoms were not located in the dif-
ference map, the Oꢁ ꢁ ꢁF distances strongly suggest H-bond-
ing between the O and F atoms, i.e. O–Hꢁ ꢁ ꢁF (Oꢁ ꢁ ꢁF ca.
Colourless crystals of [Cu2{Me2As(CH2)2OH}3](BF4)2
were obtained as a result of ligand fragmentation in the
reaction of [Cu(MeCN)4]BF4 with 2 mol. equiv. of 4 as
described above. The structure of the cation shows
(Fig. 4, Table 4) a Cu(I)ꢁ ꢁ ꢁCu(I) dimer with the three
dimethylarsinoethanol ligands bridging the metal centres,
leading to distorted pyramidal coordination at each Cu
atom, with two As and one OH group bonded to Cu1
and with one As and two OH groups bonded to Cu2.
The short dimethylene ligand backbone places the Cu
˚
2.7 A) which, together with the fact the crystals were colou-
ress, are consistent with Cu(I).
The preference for bidentate Sb2 coordination for 1 and
2 is reinforced by the isolation of [RhCl2(1)2]Cl and
[RhCl2(2)2]Cl from reaction of Na3[RhCl6] with 1 mol.
equiv. of 1 or 2 in ethanol solution (there is no evidence
for [RhCl3(1)] or [RhCl3(2)]). Spectroscopic data and
microanalyses are fully consistent with the formulation of
these compounds as distorted octahedral Rh(III) mono-
mers with mutually trans Cl ligands and two bidentate
chelating L–L units bonded via the Sb atoms only. These
˚
atoms only 2.497(1) A apart. This is towards the short
end of the range typically seen for Cu(I)–Cu(I) dimers with
bridging ligands [21]. We also note that As2, which is
2.283(1) A from Cu2, appears to shows a long range inter-
action (2.934(1) A) with Cu1. The Cu1–Cu2–As2 angle of
˚
˚
75.58(4)ꢁ also suggests that As2 is leaning towards Cu1.

M.F. Davis et al. / Journal of Organometallic Chemistry 692 (2007) 5589–5597
5593
complexes were also obtained from the stoichiometric 1:2
Rh:L–L reactionꢀs, and the Clꢀ anion may be metathesised
readily with PF6 using NH4PF6 in EtOH solution.
Using [PdCl2(MeCN)2] or [PtCl2(MeCN)2] with 1 or 2 in
MeCN/CH2Cl2 leads to formation of the neutral, distorted
square planar monomers cis-[MCl2(distibine)] in high yield.
The appearance of two MꢀCl stretches in the far-IR
spectrum confirms the cis-disposition of the Cl ligands,
and the 195Pt NMR spectrum of [PtCl2(2)] shows a single
resonance at ꢀ4490 ppm, consistent with a Cl2Sb2 donor
set at Pt(II) [7].
had changed from dark-blue to dark-red. Stirring was con-
tinued for a further 1 h, followed by the dropwise addition
of bis(2-bromoethyl)ether (2.32 g, 0.010 mol) as a thf solu-
tion (100 mL). The reaction was left to stir overnight to
allow evaporation of the ammonia. The solution was hydro-
lysed with degassed H2O (100 mL) and the organic layer
separated. The aqueous layer was washed with diethyl ether
(2 · 100 mL), and the combined organics were dried over
MgSO4. Following filtration the volatiles were removed
under reduced pressure, yielding 1 as a pale yellow oil
(3.95 g, 63%). 1H NMR (CDCl3): d = 2.06 (t) [4H] CH2Sb,
3.58 (t) [4H] CH2O, 7.15–7.42 (m) [20H] Ph. 13C{1H} NMR
(CDCl3): d = 22.53 (CH2Sb), 69.27 (CH2O), 129.01, 129.32,
136.61 (Ph). EIMS: m/z = 624 [1]+.
3. Conclusions
We have developed high yielding routes to rare examples
of Sb2O- and As2O-donor facultative ligands and shown
that these behave as Sb2- (or As2-) bound bidentates
towards tetrahedral Cu(I) and Ag(I), and for 1 and 2,
towards octahedral Rh(III) and square planar Pd(II) and
Pt(II) ions. Incorporation of dimethylene linkages between
the donor atoms is usually problematic for arsine and stibine
ligands, and while ligand 4 shows some C–O bond fission
during attempts to purify 4 by distillation and during com-
plexation with Cu(I), the other ligands appear to be signifi-
cantly more stable. The crystal structure of the Cu(I)–Cu(I)
fragmentation product, [Cu2{Me2As(CH2)2OH}3](BF4)2
incorporating dimethylarsinoethanol bridging ligands
authenticates the occurrence of metal promoted C–O bond
fission in compound 4, leading to unsymmetrical coordina-
tion at each Cu atom and a rather short Cuꢁ ꢁ ꢁCu contact
Tetrabromide derivative of 1: compound 1 (0.200 g,
0.32 mmol) was dissolved in CH2Cl2 (10 mL) and bromine
diluted with CH2Cl2 was added dropwise until a permanent
orange colour was produced. The reaction mixture was
stirred for 1 h, the resulting white solid was filtered off,
rinsed with CH2Cl2 and dried under reduced pressure
(0.22 g, 73%). Anal. Calc. for C28H28Br4OSb2 Æ CH2Cl2:
C, 33.9; H, 2.9. Found: C, 33.4; H, 3.0%. 1H NMR
(CDCl3): d = 3.55 (t) [4H] CH2O, 4.36 (t) [4H] CH2Sb,
7.33–7.47 (m) [12H], 8.02–8.13 (m) [8H] Ph. 13C{1H}
NMR (CDCl3): d = 55.27 (CH2Sb), 67.27 (CH2O),
130.16, 132.18, 134.69, 139.30 (Ph).
4.2. O{(CH2)2SbMe2}2 (2)
Hydrogen chloride gas was bubbled through a solution of
dimethylphenylstibine (7.00 g, 0.031 mol) in toluene
(100 mL) for 15 min. The solution was allowed to stir for a
further 20 min and was then purged with N2 for 30 min.
The toluene solution was added to a solution of sodium
(1.55 g, 0.067 mol) in liquid ammonia (250 mL) maintained
at ꢀ78 ꢁC (acetone/CO2 slush). Within 1 h the colour of
the reaction mixture had changed from dark-blue to dark-
red. Stirring was continued for a further 2 h, followed by
the dropwise addition of bis(2-bromoethyl)ether (3.55 g,
0.015 mol) as a thf solution (100 mL). The reaction mixture
was stirred overnight to allow evaporation of the ammonia.
The solution was hydrolysed with degassed H2O (100 mL)
and the organic layer separated. The aqueous layer was
washed with diethyl ether (2 · 100 mL), and the combined
organics were dried over MgSO4. Following filtration the
volatiles were removed under reduced pressure yielding (2)
as a pale yellow oil (2.69 g, 48%). 1H NMR (CDCl3):
d = 0.78 (s) [12H] Me, 1.72 (t) [4H] CH2Sb, 3.62 (t) [4H]
CH2O. 13C{1H} NMR (CDCl3): d = ꢀ5.27 (MeSb), 17.90
(CH2Sb), 69.81 (CH2O). EIMS: m/z = 361 [2ꢀMe]+.
˚
(ca. 2.5 A).
4. Experimental
Infrared spectra were recorded as CsI discs using a Per-
kin-Elmer 983G spectrometer over the range 4000–
200 cmꢀ1. Mass spectra were run by electron impact on a
VG-70-SE Normal geometry double focusing spectrometer
or by positive ion electrospray (MeCN solution) using a
VG Biotech platform. 1H and 13C{1H} NMR spectra were
recorded using a Bruker AM300 spectrometer operating at
300 and 75.48 MHz, respectively. 63Cu and 195Pt NMR
spectra were recorded using a Bruker DPX400 spectrome-
ter operating at 106.1 or 85.6 MHz respectively and are ref-
erenced to [Cu(MeCN)4]+ and 1 mol dmꢀ3 aqueous
Na2[PtCl6], respectively. Microanalyses were undertaken
by the University of Strathclyde microanalytical service.
Solvents were dried prior to use and all preparations
were undertaken using standard Schlenk techniques and
degassed solvents under a N2 atmosphere.
Methiodide of 2: compound 2 (0.20 g, 0.53 mmol) was
dissolved in dry acetone (50 mL) and treated with an excess
of methyl iodide. The reaction was left to stir for 30 min
and the white solid was filtered, washed with acetone and
dried under reduced pressure (Yield: 0.19 g, 54%). Anal.
Calc. for C10H26I2OSb2 Æ 1/3Me2CO: C, 19.5; H, 4.2.
4.1. O{(CH2)2SbPh2}2 (1)
Diphenylchlorostibine [7] (6.23 g, 0.020 mol) was added
to a solution of sodium (0.97 g, 0.042 mol) in liquid ammo-
nia (250 mL) maintained at ꢀ78 ꢁC (acetone/CO2 slush).
Within 30 min of stirring the colour of the reaction mixture
1
Found: C, 19.5; H, 4.0%. H NMR (d6-DMSO): d = 1.62

5594
M.F. Davis et al. / Journal of Organometallic Chemistry 692 (2007) 5589–5597
(s) [18H] Me, 2.59 (t) [4H] CH2Sb, 3.95 (t) [4H] CH2O.
13C{1H} NMR (d6-DMSO): d = 1.66 (MeSb), 22.08
(CH2Sb), 65.58 (OCH2). Electrospray MS (MeCN): m/z =
533 [Me3Sb(CH2)2O(CH2)2SbMe3I]+, 203 [Me3Sb(CH2)2-
In one case the 1H NMR spectrum of the product
isolated as above showed some additional resonances,
hence purification by distillation was attempted, giving
two fractions. Fraction 1: B.p. 58 ꢁC at 0.05 mmHg turned
out to be ligand 4, with identical spectroscopic features to
those quoted above. Fraction 2: B.p. 74 ꢁC at 0.05 mm Hg;
1H NMR spectrum (CDCl3): d = 0.93 (s) [6H] Me, 1.70 (t)
[2H] CH2As, 3.54 (t) [2H] CH2O. GCEI MS: m/z = 150
[Me2As(CH2)2OH]+.
O(CH2)2SbMe3]2+
.
4.3. O{(CH2)2AsPh2}2 (3)
Lithium metal (0.34 g, 0.048 mol) was added to a solu-
tion of triphenylarsine (5.0 g, 0.016 mol) in thf (100 mL).
This was refluxed for 1 h to give a dark red solution and
4.5. [Cu(1)2]BF4
t
then left stirring for 8 h. BuCl (1.4 mL, 0.013 mol) was
added dropwise to remove the PhLi by-product and the
mixture was stirred for 1 h, turning to a lighter orange/
red colour. To this was added a solution of O(CH2CH2Br)2
(0.70 mL, 5.60 mmol) in thf (10 mL) to give an off-white
reaction mixture, which upon refluxing for 2 h turned to
a green oil. Aqueous NH4Cl (50 mL) was added and the
organic fraction was separated. The aqueous layer was
washed with thf (20 mL) and the combined organic frac-
tions were dried over MgSO4 for 8 h. The solvent was
removed in vacuo to give 3 as a yellow waxy oil which
was stored in a Schlenk tube over molecular sieves (2.3 g,
[Cu(MeCN)4]BF4 (0.31 g, 1.00 mmol) was dissolved in
degassed ethanol (75 mL), (1) (0.62 g, 1.00 mmol) was
added dropwise as a CH2Cl2 solution (10 mL). The reac-
tion stirred for 2 h at room temperature and the resulting
white precipitate was filtered, washed with ethanol and
dried under reduced pressure. The filtrate was reduced in
volume and placed in the freezer to yield white crystals
(0.15 g) giving a combined yield of 0.33 g, 94% based on
1. Anal. Calc. for C56H56BCuF4O2Sb4: C, 48.1; H, 4.0.
1
Found: C, 47.9; H, 3.6%. H NMR (CDCl3): d = 2.33 (t)
[4H] CH2Sb, 3.62 (t) [4H] CH2O, 7.15–7.45 (m) [20H] Ph.
13C{1H} NMR (CDCl3): d = 22.71 (CH2Sb), 67.10
(CH2O), 130.22, 130.78, 132.17, 135.98 (Ph). 63Cu NMR
(MeCN/CDCl3): d = ꢀ229 (w1/2 = 2000 Hz). Electrospray
MS (MeCN): m/z = 1311 [Cu(1)2]+, 728 [Cu(1)(MeCN)]+.
1
77%). H NMR (CDCl3): d = 2.27 (t) [4H] CH2As, 3.55
(t) [4H] CH2O, 7.31–7.44 (m) [20H] Ph. 13C{1H} NMR
(CDCl3): d = 28.96 (CH2As), 68.86 (CH2O), 128.96,
129.22, 133.69, 140.96 (Ph). EIMS: m/z = 530 [3]+, 453
[3ꢀPh]+.
IR (Nujol): 1072 (BF4ꢀ) cmꢀ1
.
Methiodide of 3: compound 3 (0.2 g, 0.38 mmol) in ace-
tone (5 mL) and MeI (0.2 g, 1.42 mmol) was added and the
reaction mixture was stirred for 72 h. The volatiles were
removed in vacuo to leave a white solid. 1H NMR
(CDCl3): d = 2.77 (s) [6H] Me, 3.70–3.77 (m) [8H], CH2,
7.61–7.90 (m) [20H] Ph. 13C{1H} NMR (CDCl3):
d = 10.27 (MeAs), 27.65 (CH2As), 65.27 (CH2O), 122.16
(ipso C), 130.60, 132.24, 133.63 (Ph). Electrospray MS
(MeCN): m/z = 687 [MePh2As(CH2)2O(CH2)2AsPh2MeI]+;
4.6. [Ag(1)2]BF4
This reaction was carried out in the absence of light and
the product was treated as light sensitive. AgBF4 (0.19 g,
1.00 mmol) was dissolved in degassed methanol (30 mL).
The ligand (1) (0.62 g, 1.00 mmol) was dissolved in CH2Cl2
(10 mL) and added dropwise to the methanolic solution.
The reaction was stirred for 3 h and the resulting off-white
precipitate was filtered, washed with methanol and dried
under reduced pressure (0.21 g, 58% based on 1). Anal.
Calc. for C56H56AgBF4O2Sb4: C, 46.6; H, 3.9. Found: C,
46.8; H, 4.0%. 1H NMR (CDCl3): d = 2.33 (t) [4H] CH2Sb,
3.64 (t) [4H] CH2O, 7.11–7.49 (m) [20H] Ph. 13C{1H}
NMR (CDCl3): d = 22.25 (CH2Sb), 67.3 (CH2O), 129.37,
129.90, 135.69 (Ph). Electrospray MS (MeCN): m/
280 [MePh2As(CH2)2O(CH2)2AsPh2Me]2+
.
4.4. O{(CH2)2AsMe2}2 (4)
Me2AsI [22] (8.4 g 0.036 mol) was added dropwise to a
flask containing small pieces of sodium metal (2.00 g,
0.087 mol) in thf (200 mL). The reaction mixture was
heated to 85 ꢁC for 1 h, whereupon the reaction solution
changed from yellow to white and then to green. It was
then left stirring for 8 h. O(CH2CH2Br)2 (4.20 g,
0.018 mol) was added dropwise, and the mixture was stir-
red for a further 8 h. Degassed H2O was added until all
the solids dissolved. The organic layer was separated and
the aqueous washed with diethyl ether (2 · 40 mL). The
combined organic phases were dried over MgSO4 for 8 h.
The solvent was removed in vacuo to give 4 as a yellow
z = 1355 [Ag(1)2]+. IR (Nujol): 1078 (BF4ꢀ) cmꢀ1
.
4.7. [RhCl2(1)2]Cl
Na3RhCl6 Æ 12H2O (0.30 g, 0.50 mmol) was dissolved in
degassed water (40 mL), the ligand (1) (0.62 g, 1.00 mmol)
was added dropwise as an ethanolic solution (50 mL). The
solution turned orange with a yellow precipitate forming
and the reaction mixture stirred for a further 1 h. The yel-
low solid was filtered, washed with diethyl ether and then
recystallised from EtOH/CH2Cl2 before drying under
reduced pressure. (0.48 g, 66%). Anal. Calc. for
C56H56Cl3O2RhSb4 Æ CH2Cl2: C, 44.4; H, 3.8. Found: C,
1
oil (3.38 g, 67%). H NMR (CDCl3): d = 0.94 (s) [12H]
Me, 1.68 (t) [4H] CH2As, 3.75 (t) [4H] CH2O. 13C{1H}
NMR (CDCl3): d = 9.93 (MeAs), 32.39 (CH2As), 61.58
(CH2O). EI MS: m/z = 267 [4ꢀMe]+.

M.F. Davis et al. / Journal of Organometallic Chemistry 692 (2007) 5589–5597
5595
1
44.4; H, 3.6. H NMR (CDCl3): d = 2.2–2.6 (br m) [4H]
CH2Sb, 3.7–4.0 (br m) [4H] CH2O, 7.0–7.7 (m) [20H] Ph.
Electrospray MS (MeCN): m/z = 1421 [Rh(1)2Cl2]+. IR
(Nujol): 332 m(Rh–Cl) cmꢀ1. UV/Vis (nm/CH2Cl2): 382
br (emol = 1450 cmꢀ1 molꢀ1 dm3).
4.11. [RhCl2(2)2]Cl
Na3RhCl6 Æ 12H2O (0.15 g, 0.25 mmol) was dissolved in
degassed water (40 mL), the ligand (1) (0.18 g, 0.50 mmol)
was added dropwise as an ethanolic solution (50 mL). The
solution turned orange and the reaction mixture was stirred
for a further 2 h. The solution was reduced in volume and
the yellow solid filtered off, washed with diethyl ether and
then recrystallised from chloroform and dried under
reduced pressure (0.16 g, 68%). Anal. Calc. for
C16H40Cl3O2RhSb4 Æ 2CHCl3: C, 18.0; H, 3.5. Found: C,
4.8. [PtCl2(1)]
PtCl2 (0.13 g, 0.50 mmol) was suspended in acetonitrile
(50 mL) and heated to reflux for 2 h until a yellow solution
formed. The ligand 1 (0.31 g, 0.5 mmol) was added drop-
wise as a CH2Cl2 solution (5 mL), the solution turned
orange initially then back to yellow after 20 min. The reac-
tion was left to stir for a further 2 h and the solvent was
reduced in volume under reduced pressure. The solid was
filtered, washed with diethyl ether (10 mL), and dried under
reduced pressure to yield a yellow solid (0.15 g, 33%). Anal.
Calc. for C28H28Cl2OPtSb2 Æ 1/2CH2Cl2: C, 36.7; H, 3.1.
1
17.3; H, 3.3%. H NMR (CDCl3): d = 1.35 (s) [12H] Me,
2.2–2.6 (m) [4H] CH2Sb, 3.6–4.0 (m) [4H] CH2O. Electro-
spray MS: m/z = 926 [Rh(2)2Cl2]+. IR (Nujol): 322 m(Rh–
Cl) cmꢀ1
.
4.12. [PtCl2(2)]
Found: C, 36.5; H, 2.5%. H NMR (d6-dmso): d = 6.9–
PtCl2 (0.13 g 0.50 mmol) was suspended in acetonitrile
(50 mL) and heated to reflux for 2 h until the suspension
dissolved to give a yellow solution. The ligand 2 (0.18 g,
0.50 mmol) was added dropwise as a CH2Cl2 solution
(5 mL), the solution turned orange initially then back to
yellow after 20 min. The reaction was left to stir for a
further 2 h and the solvent was reduced in volume under
reduced pressure. The solid was filtered, washed with
diethyl ether (10 mL), and dried under reduced pressure
to yield a yellow solid (0.18 g, 58%). Anal. Calc. for
C8H20Cl2OPtSb2: C, 15.0; H, 3.1. Found: C, 15.4; H,
1
7.8 (br m) [20H] Ph, 3.2–4.1 (br m) [4H] OCH2, 2.1–2.8
(br m) [4H] SbCH2. IR (Nujol): 318, 332 m(Pt–Cl) cmꢀ1
.
4.9. [Cu(2)2]BF4
[Cu(MeCN)4]BF4 (0.31 g, 0.01 mol) was dissolved in
degassed ethanol (75 mL), (2) (0.38 g, 0.01 mol) was added
dropwise as a CH2Cl2 solution (10 mL). The reaction mix-
ture was stirred for 2 h and the resulting white precipitate
was filtered off, washed with ethanol and dried under
reduced pressure (0.17 g). The filtrate was reduced in
volume and placed in the freezer to yield white crystals
(0.07 g) giving a combined yield of 0.24 g, 53%. Anal. Calc.
for C16H40BCuF4O2Sb4: C, 21.3; H, 4.5. Found: C, 20.7;
1
2.9%. H NMR (CDCl3): d = 1.18 (s) [12H] Me, 2.11 (t)
[4H] SbCH2, 3.82 (t) [4H] OCH2. 195Pt NMR (CH2Cl2/
CDCl3): d = ꢀ4490 (w1/2 = 2000 Hz). IR (Nujol): 279,
301 m(Pt–Cl) cmꢀ1
4.13. [PdCl2(2)]
.
1
H, 3.9%. H NMR (CDCl3): d = 1.53 (s) [12H] Me, 2.33
(t) [4H] SbCH2, 3.62 (t) [4H] CH2O. 13C{1H} NMR
(CDCl3): d = ꢀ2.56 (Me), 19.89 (CH2Sb), 67.83 (CH2O).
63Cu NMR (CH2Cl2/CDCl3): d = ꢀ194 (w1/2 = 400 Hz).
Electrospray MS (MeCN): m/z = 816 [Cu(2)2]+, 481
PdCl2 (0.09 g, 0.50 mmol) was suspended in acetonitrile
(50 mL) and heated to reflux for 2 h until the suspension
dissolved to give a yellow solution. The solution was left
to cool and the ligand 2 (0.18 g, 0.50 mmol) was added
dropwise as a CH2Cl2 solution (5 mL), the reaction was left
to stir for a further 2 h. The solid was filtered, washed with
diethyl ether (10 mL), and dried under reduced pressure to
yield a yellow solid (0.13 g, 49%). Anal. Calc. for
C8H20Cl2OPdSb2: C, 17.4; H, 3.6. Found: C, 17.1; H,
[Cu(2)(CH3CN)]+. IR (Nujol): 1060 (BF4ꢀ) cmꢀ1
.
4.10. [Ag(2)2]BF4
This reaction was carried out in the absence of light
and the product was treated as light sensitive. AgBF4
(0.19 g, 0.01 mol) was dissolved in degassed methanol
(30 mL). The ligand (2) (0.38 g, 0.01 mol) was dissolved
in CH2Cl2 (10 mL) and added dropwise to the methanolic
solution. The reaction mixture was stirred for 3 h and
the off-white precipitate was filtered off, washed with
methanol and dried under reduced pressure (0.21 g,
74%). Anal. Calc. for C16H40AgBF4O2Sb4 Æ H2O: C,
19.9; H, 4.4. Found: C, 19.5; H, 4.0%. 1H NMR
(CDCl3): d = 0.98 (s) [12H] Me, 2.01 (t) [4H] CH2Sb,
3.72 (t) [4H] CH2O. 13C{1H} NMR (CDCl3): d = ꢀ3.30
(Me), 19.15 (CH2Sb), 67.10 (CH2O). Electrospray MS:
m/z = 860 [Ag(2)2]+. IR (Nujol): 3350 br m(H2O), 1650
1
3.4%. H NMR (CDCl3): d = 1.31 (s) [12H] Me, 2.11 (t)
[4H] SbCH2, 3.86 (t) [4H] OCH2. 13C{1H} NMR (CDCl3):
d = 1.71 (MeSb), 20.75 (CH2Sb), 67.63 (CH2O). IR
(Nujol): 296, 336 m(Pd–Cl) cmꢀ1
.
4.14. [Cu(3)2]BF4
Ligand 3 (0.53 g, 1.0 mmol) in CH2Cl2 was added drop-
wise to a solution of [Cu(MeCN)4]BF4 (0.315 g, 1.0 mmol)
in methanol (10 mL). The reaction mixture was stirred for
0.5 h and the light yellow solution was then concentrated to
half the volume in vacuo. Colourless crystals were obtained
d(H2O), 1071 m(BF4)ꢀ cmꢀ1
.

5596
M.F. Davis et al. / Journal of Organometallic Chemistry 692 (2007) 5589–5597
by cooling this solution in the freezer over several days.
These were filtered off to give a white solid which was dried
in vacuo (0.36 g, 60%). Anal. Calc. for C56H56As4BCu-
F4O2 Æ 2CH2Cl2: C, 50.5; H, 4.4. Found: C, 51.0; H,
was dried in vacuo. Electrospray MS (MeCN): m/z = 627
1
[Cu(4)2]+, 386 [Cu(4)(MeCN)]+, 345 [Cu(4)]+. H NMR
(CDCl3): d = 1.38 (s) [12H] CH3, 2.08 (t) [4H] CH2As,
3.99 (br) [4H] OCH2. 63Cu NMR (CH2Cl2): d = ꢀ16. IR
1
4.8%. H NMR (CDCl3): d = 2.62 (br) [4H] CH2As, 3.84
(Nujol): 1065 (BF4ꢀ) cmꢀ1
.
(br) [4H] OCH2, 7.28–7.39 (m) [20H] Ph. 63Cu NMR
(CH2Cl2): d = ꢀ139. IR (Nujol): 1050 (BF4ꢀ) cmꢀ1
.
4.17. [Ag(4)2]BF4
4.15. [Ag(3)2]BF4
Ligand 4 (0.07 g, 0.25 mmol) was added dropwise to a
solution of AgBF4 (0.10 g, 0.50 mmol) in degassed
methanol (10 mL) in a foil-wrapped schlenk. After stirring
for ca. 2 h the solvent was then removed in vacuo to give a
light brown oily paste. Electrospray MS (MeCN): m/
z = 539 [Ag(4)(4ꢀCH2CH2AsMe2)]+, 407 [Ag(4)(H2O)]+,
Ligand 3 (0.57 g, 1.1 mmol) in CH2Cl2 was added drop-
wise to a solution of AgBF4 (0.21 g, 1.1 mmol) in methanol
(10 mL) in a foil-wrapped flask. The reaction mixture was
stirred for 1 h, the brown solution was then filtered and col-
ourless crystals were obtained by leaving the filtrate in the
dark for one month. (0.29 g, 43%). Anal. Calc. for
C56H56AgAs4BF4O2 Æ 2MeOH: C, 52.8; H, 4.9. Found: C,
52.1; H, 4.4%. Electrospray MS (MeCN): m/z = 1167
1
389 [Ag(4)]+. H NMR (CDCl3): d = 1.42 (s) [12H] Me,
2.13 (t) [4H] CH2As, 3.95 (t) [4H] OCH2. 13C{1H} NMR
(CDCl3): d = 8.88 (Me), 31.79 (CH2As), 58.72 (CH2O).
IR (Nujol): 1057 (BF4ꢀ) cmꢀ1
.
1
[Ag(3)2]+. H NMR (CDCl3): d = 2.41 (br) [4H] CH2As,
3.48 (br) [4H] OCH2, 7.17–7.39 (m) [20H] Ph. 13C{1H}
4.18. X-ray crystallography
NMR (CDCl3): d = 29.17 (CH2As), 66.89 (CH2O), 129.26,
129.88, 132.75, 134.95 (Ph). IR (Nujol): 1060 (BF4ꢀ) cmꢀ1
.
Details of the crystallographic data collection and
refinement parameters are given in Table 5. Colourless
crystals of [Ag(1)2]BF4 Æ CH2Cl2, [Cu(3)2]BF4 Æ MeOH,
[Ag(3)2]BF4 Æ MeOH and [Cu2{Me2As(CH2)2OH}3](BF4)2
were grown by cooling concentrated solutions of the
complexes in MeOH (ca. ꢀ18 ꢁC). Data collection used a
Nonius Kappa CCD diffractometer (T = 120 K) and with
monochromated (graphite or confocal mirrors) Mo Ka
4.16. [Cu(4)2]BF4
Ligand 4 (0.07 g, 0.25 mmol) was added dropwise to a
solution of [Cu(MeCN)4]BF4 (0.156 g, 0.50 mmol) in
degassed methanol (10 mL), this was stirred for 2 h before
the solution was then reduced in vacuo to give a green
paste. This dissolved partially in methanol (10 mL), the
colourless mother liquor was then transferred and diethyl
ether (10 mL) added to produce a green fluffy solid. This
was left to stand, the solvent was decanted off and the solid
˚
X-radiation (k = 0.71073 A). Structure solution and
refinement were routine [23–25] and H atoms were included
in calculated positions. Selected bond lengths and angles
are given in Tables 1–4.
Table 5
Crystallographic parameters
Complex
Formula
M
[Cu(3)2]BF4 Æ MeOH
C57H60As4BCuF4O3
1243.08
Monoclinic
P21/c (#14)
11.209(3)
17.931(4)
26.177(5)
90
90.359(10)
90
5261.4(19)
4
[Ag(1)2]BF4 Æ CH2Cl2
[Ag(3)2]BF4 Æ MeOH
C57H60AgAs4BF4O3
1287.41
[Cu2{Me2As(CH2)2OH}3](BF4)2
C12H33As3B2Cu2F8O3
C57H58AgBCl2F4O2Sb4
1527.61
Monoclinic
P21/c (#14)
13.1670(10)
16.5702(15)
26.543(3)
90
101.943(6)
90
5665.8(9)
4
750.84
Orthorhombic
P212121 (#19)
8.1798(10)
15.120(3)
20.506(5)
90
90
90
2536.1(8)
4
5.631
Crystal system
Space group
Triclinic
ꢀ
P1 ð#2Þ
˚
a (A)
11.387(2)
13.633(3)
17.061(3)
91.285(10)
93.574(10)
92.830(10)
2639.4(8)
2
˚
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
3
˚
U (A )
Z
l (mmꢀ1
)
2.970
2.370
2.928
Total number of reflections
Unique reflections
Rint
62586
12178
0.142
73096
12971
0.065
57994
12167
0.175
16310
5726
0.068
Number of parameters
R1 [I0 > 2r(I0)]
wR2 [I0 > 2r(I0)]
R1 [all data]
633
0.057
0.101
0.143
640
0.044
0.096
0.067
633
0.066
0.112
0.162
271
0.057
0.090
0.099
wR2 [all data]
0.128
0.104
0.141
0.104
P
P
P
P
2
1=2
R1 ¼ kF oj ꢀ jF ck= jF oj; wR2 ¼ ½ ðF 2o ꢀ F c2Þ = wF o4ꢂ
.

M.F. Davis et al. / Journal of Organometallic Chemistry 692 (2007) 5589–5597
5597
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We thank the EPSRC for support (GR/T09613/01 and
EP/D003148) and Johnson Matthey plc for precious metal
loans.
W. Levason, M.L. Matthews, G. Reid, M. Webster, Dalton Trans.
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Appendix A. Supplementary material
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CCDC 652335, 652336, 652337 and 652338 contain the
supplementary crystallographic data for (Cu/3), (Ag/1),
(Ag/3) and Cu. These data can be obtained free of charge
via http://www.ccdc.cam.ac.uk/conts/retrieving.html, or
from the Cambridge Crystallographic Data Centre, 12
Union Road, Cambridge CB2 1EZ, UK; fax: (+44) 1223-
336-033; or e-mail: deposit@ccdc.cam.ac.uk. Supplemen-
tary data associated with this article can be found, in the
online version, at doi:10.1016/j.jorganchem.2007.08.034.
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