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S.L. Rose et al. / Inorganica Chimica Acta 362 (2009) 5237–5244
ately giving a cream precipitate. The solid was isolated by filtra-
tion, washed with methanol (5 mL), water (5 mL) and petroleum
spirits (5 mL) and dried in vacuo to give 4a (369 mg, 85%). Anal.
Calc. for C108H90BP4Pt2S2Tl: C, 59.47; H, 4.16. Found: C, 59.35; H,
by vapour diffusion from dichloromethane–ether gave orange
blocks, together with some white powdery material (cis-
PtBr2(PPh3)2). Anal. Calc. for C72H60Br6P4Pt2S2Tl2: C, 36.16; H,
2.53%. Found: C, 36.39; H, 2.55%. ESI MS, positive-ion [Pt2(l-
4.23%. ESI MS, [Pt2(
l
-S)2(PPh3)4TlPh2]+ m/z 1861 (100%). 31P{1H}
S)2(PPh3)4TlBr2]+, m/z 1867 (100%); negative-ion [TlBr4]ꢀ, m/z 525
(100%). 31P{1H} NMR, d 16.0 [d, 1J(PtP) 3155, 2J(TlP) 257].
NMR, d 18.9 [s, 1J(PtP) 3022].
5.4. Synthesis of [Pt2(l-S)2(PPh3)4TlPh2]PF6 (4b)
5.9. Crystal structure determinations
Following the procedure for 4a [Pt2(
l
-S)2(PPh3)4] 1 (300 mg,
Crystal data and refinement details for the structures are given
in Table 2. X-ray intensity data were collected on a Bruker SMART
CCD diffractometer using standard procedures and software.
Empirical absorption corrections were applied (SADABS) [51].
Structures were solved by direct methods and developed and re-
fined on F2o using the SHELX programmes [52] operating under WINGX
[53]. Hydrogen atoms were included in calculated positions.
0.200 mmol) and Ph2TlBr (97 mg, 0.221 mmol) gave a pale yellow
precipitate of 4b (300 mg, 75%) upon addition of NH4PF6
(200 mg, 1.23 mmol) to the filtered reaction solution. ESI MS,
[Pt2(
5.5. Synthesis of [Pt2(
Following the procedure for 4a, [Pt2(
l
-S)2(PPh3)4TlPh2]+, m/z 1861 (100%).
l-S)2(PPh3)4Tl(C6H4Cl-p)2]BPh4 (4c)
l
-S)2(PPh3)4] 1 (200 mg,
5.9.1. [Pt2(l-S)2(PPh3)4TlPh2]BPh4 (4a)
0.133 mmol) and BrTl(C6H4Cl-p)2 3b (74 mg, 0.146 mmol) in meth-
anol (25 mL), with NaBPh4 (200 mg, 0.585 mmol) gave 4c as a
cream powder (215 mg, 72%). Anal. Calc. for C108H88BCl2P4Pt2S2Tl:
Yellow crystals were obtained by vapour diffusion of Et2O into a
CH2Cl2 solution of the complex at room temperature; the crystals
readily lost solvent when removed from the supernatant.
C, 57.65; H, 3.94%. Found: C, 57.67; H, 4.09%. ESI MS, [Pt2(
l
-
Refinement of the cation and anion gave R1 0.075, with 10 resid-
ual peaks of 4–10 e Åꢀ3, which were associated with a region of
solvent about 1/2, 1/2, 1/2. These appeared to be very disordered
CH2Cl2 and/or Et2O, which could not be modelled sensibly. This
residual electron density was removed using the SQUEEZE routine
of PLATON [54], which suggested there were approximately three
solvent molecules on this site. Subsequent refinement against the
corrected data led to the final residuals given.
S)2(PPh3)4Tl(C6H4Cl-p)2]+, m/z 1930 (100%). 31P{1H} NMR, d 18.7
[s, 1J(PtP) 3036].
5.6. Synthesis of [Pt2(l-Se)2(PPh3)4TlPh2]BPh4 (5)
A mixture of [Pt2(l-Se)2(PPh3)4] (304 mg, 0.190 mmol) and
Ph2TlBr 3a (98 mg, 0.224 mmol) in methanol (30 mL) was stirred
for 16 h to give a slightly cloudy dark brown solution. After filtra-
tion, NaBPh4 (200 mg, 0.585 mmol) was added to the filtrate giving
a brown precipitate, which was isolated by filtration, washed with
water (10 mL), methanol (10 mL) and petroleum spirits (10 mL),
and dried in vacuo to give 5 as a tan powder (333 mg, 77%). Crys-
tallisation by vapour diffusion of diethyl ether into a dichlorometh-
ane solution gave dark orange-brown blocks that lost solvent and
crumbled upon removal from the supernatant. Anal. Calc. for
C108H90BP4Pt2Se2Tl: C, 57.02; H, 3.99. Found: C, 57.01; H, 3.94%.
5.9.2. [Pt2(l-S)2(PPh3)4TlBrPh]BPh4 (6)
Yellow-orange crystals were obtained by vapour diffusion of
Et2O into a CH2Cl2 solution of the complex at room temperature;
in contrast to 4a the crystals were stable when removed from
the supernatant. The presence of the heavy elements Pt, Tl, P, S
and Br was confirmed by EDAX analysis on a crystal. Some residual
electron density (3–4 e Åꢀ3) remained in the final difference map,
which was clearly very poorly-ordered solvent, but this could not
be sensibly modelled.
ESI MS, [Pt2(
l
-Se)2(PPh3)4TlPh2]+, m/z 1956 (100%). 31P{1H} NMR,
d 18.3 [s, 1J(PtP) 3061].
5.9.3. [Pt2(l-S)2(PPh3)4TlBr2][TlBr4] (7)
5.7. Synthesis of [Pt2(
l
-S)2(PPh3)4TlBrPh]BPh4 (6)
Orange block crystals were obtained by vapour diffusion of Et2O
into a CH2Cl2 solution of the complex at room temperature. The
structure was solved by direct methods and developed normally.
However when the main, expected, structure had been refined,
there remained a large peak of electron density (12 e Åꢀ3) near
the Tl(1) atom, and a smaller one on a nearby inversion centre.
These were interpreted as coming from a small fraction (< 10%)
which had co-crystallised with the main TlBr2 species, containing
a Tl2Br5 moiety bridging two Pt2S2 clusters. This refined sensibly.
Hence the main species in the unit cell contains a tetrahedral Tl(III)
coordinated to two Brꢀ and two S atoms from one Pt2S2 unit (Fig. 3).
The minor component has a pseudo-tetrahedral Tl(III) coordinated
to one of the S atoms and to three Brꢀ anions, two of which coincide
with the Br positions of the major component, while the third
bridges to a centrosymmetrically related neighbour (Figs. 4 and 5).
The extra Brꢀ in the minor component is presumably compen-
sated for by incomplete occupancy of the [TlBr4]ꢀ site, but this
was not accommodated in the refinement so this small effect
would have been hidden in the temperature factors of the anion.
A mixture of [Pt2(
l
-S)2(PPh3)4] 1 (200 mg, 0.133 mmol) and
PhTlBr2 (70 mg, 0.159 mmol) in methanol (20 mL) was stirred for
16 h, giving a cloudy yellow solution. After filtration, NaBPh4
(200 mg, 0.585 mmol) was added to the clear yellow filtrate, giving
a pale orange precipitate. The product was isolated by filtration,
washed with methanol (5 mL), water (5 mL) and petroleum spirits
(5 mL), and dried in vacuo to give 6 (159 mg, 55%). Anal. Calc. for
C102H85BBrP4Pt2S2Tl: C, 56.09; H, 3.92. Found: C, 56.21; H, 4.08%.
ESI MS, [Pt2(
l
-S)2(PPh3)4TlBrPh]+, m/z 1865 (100%). 31P{1H} NMR,
d 17.9 [s, 1J(PtP) 3100], 17.2 [s, 1J(PtP) 3090].
5.8. Synthesis of [Pt2(l-S)2(PPh3)4TlBr2][TlBr4] (7)
An aqueous solution of TlBr3 (ca. 0.0493 mmol Tl mLꢀ1) was
prepared by adding a slight excess of bromine to a suspension of
TlBr (350 mg) in water (25 mL) until a permanent orange colour
was formed, followed by briefly removing the excess bromine un-
der reduced pressure.
To a suspension of [Pt2(l-S)2(PPh3)4] 1 (410 mg, 0.273 mmol) in
Acknowledgements
methanol (30 mL) was added aqueous TlBr3 (11 mL, 0.546 mmol),
resulting in rapid formation of an orange suspension. The mixture
was stirred for 5 h, the product filtered, washed with cold metha-
nol (2 ꢂ 5 mL) and dried to give 7 (543 mg, 83%). Recrystallisation
We thank the University of Waikato and the National University
of Singapore for financial support of this work, Dr. Tania Groutso
(University of Auckland) and Dr. Jan Wikaira (University of Canter-