W. Henderson, A.G. Oliver / Inorganica Chimica Acta 416 (2014) 49–56
55
4.4. Reaction of cis-[PtCl2(PPh3)2], Na2S and EtNH2 in ethanol with ESI
MS monitoring
gave 31P{1H} NMR data that were virtually indistinguishable from
the PFÀ6 salt 2ÁPF6 [13].
This reaction was carried out as per the preceding reaction but
replacing ammonia with ethylamine solution (0.5 mL), giving a
yellow suspension. ESI MS m/z 1514.37 (calculated 1514.32),
4.8. Synthesis of 2-chloro-1-methylpyridinium tetraphenylborate
A
solution of 2-chloro-1-methylpyridinium iodide (1.00 g,
[Pt2(l-S)(l
-NHEt)(PPh3)4]+ (100%). Addition of 2 drops 0.2% formic
3.60 mmol) in water (30 mL) was filtered to remove a small
amount of dark impurity. To this solution was added a solution
of NaBPh4 (1.50 g, 4.39 mmol) in water (20 mL), immediately form-
ing a milky white precipitate. The precipitate was filtered, washed
with water (2 Â 20 mL) and dried to give the product (1.42 g, 88%).
The compound can be purified by recrystallisation from hot
acetone.
acid solution to the aliquot for MS analysis resulted in dissolution
of the yellow solid giving a clear solution; ESI MS analysis showed
[Pt2(
mately equal amounts.
l-S)(l l
-NHEt)(PPh3)4]+ and [Pt2( -S)2(PPh3)4 + H]+ in approxi-
4.5. Synthesis of [Pt2(l-S)(l-NH2)(PPh3)4]BPh4 from cis-[PtCl2(PPh3)2],
NH3 and Na2S
4.9. Synthesis of [Pt2(
l
-S)(
l
-NH2)(PPh3)4]BPh4 (3ÁBPh4) from
cis-[PtCl2(PPh3)2] (361 mg, 0.457 mmol) was suspended in eth-
anol (40 mL), concentrated aqueous ammonia (4 mL) added, and
the mixture stirred for 5 min. to give an almost clear, colourless
solution. To this was added dropwise a freshly prepared solution
of Na2S 9H2O (110 mg, 0.458 mmol) in water (5 mL), resulting in
an immediate yellow colouration to the solution followed by the
gradual formation of a yellow precipitate. The mixture was stirred
for 72 h, with no further change. The mixture was filtered to
give a bright yellow solid (105 mg, which was shown to be
[Pt2( -S)2(PPh3)4] using 2-chloro-1-methylpyridinium tetraphenylborate
l
A suspension of [Pt2(
2-chloro-1-methylpyridinium tetraphenylborate (92 mg, 0.206
mmol) in methanol (25 mL) was stirred for 24 h, giving
l-S)2(PPh3)4] (300 mg, 0.200 mmol) and
a
pinkish-orange suspension. Concentrated aqueous ammonia
(4 mL, excess) was added, with no immediate change, and the
mixture was stirred for 48 h giving a cream suspension. The solid
product was filtered, washed with methanol (5 mL) and dried
under vacuum to give 3ÁBPh4 (255 mg, 71%). ESI MS m/z 1486.98,
[Pt2(l-S)2(PPh3)4] from ESI MS analysis of an acidified sample),
and
a
pale yellow filtrate. Addition of NaBPh4 (300 mg,
[Pt2(l-S)(l
-NH2)(PPh3)4]+ (100%).
0.878 mmol) to the filtrate resulted in immediate formation of a
cream precipitate which was filtered, washed with methanol–
water (1:3, 10 mL) and dried under vacuum to give 3ÁBPh4
(90 mg, 22% based on cis-[PtCl2(PPh3)2]). Found: C, 63.62; H,
4.69; N, 0.80. C96H82BNP4Pt2S requires C, 63.80; H, 4.58; N, 0.78%.
4.10. X-ray structure determination on [Pt2(l-S)(l-NH2)(PPh3)4]BPh4
(3ÁBPh4)
Yellow-orange block crystals were obtained by vapour diffusion
of diethyl ether into a dichloromethane solution of the complex at
room temperature. An arbitrary sphere of data was collected on a
yellow block-like crystal, having dimensions of 0.192 Â 0.123 Â
0.105 mm, on a Bruker APEX-II diffractometer using a combination
ESI MS showed [Pt2(
l
-S)(
l
-NH2)(PPh3)4]+ as the dominant base
peak, with a very minor dication at ca. m/z 751 assigned as
[Pt2(l-S)2(PPh3)4
+
2H]2+
. d 21.2
31P{1H} NMR (162 MHz),
[m, 1J(PtP) 2610 and 17.8 [m, 1J(PtP) 3313]. 1H NMR, d 7.49–6.89
(m, Ph) and À0.41 (s, br, NH2).
of
x- and u-scans of 0.5° [35]. Data were corrected for absorption
and polarisation effects and analysed for space group determina-
tion [36]. The structure was solved by Patterson methods and
expanded routinely. The model was refined by full-matrix least-
squares analysis of F2 against all reflections. All non-hydrogen
atoms were refined with anisotropic thermal displacement param-
eters. Unless otherwise noted, hydrogen atoms were included in
calculated positions. Thermal parameters for the hydrogens were
tied to the isotropic thermal parameter of the atom to which they
are bonded (1.2 Â Ueq(C,N)).
4.6. Synthesis of [Pt2(
l
-S)(
l
-I)(PPh3)4]PF6 (2ÁPF6)
A suspension of [Pt2(
l
-S)2(PPh3)4] (281 mg, 0.187 mmol) and
2-chloro-1-methylpyridinium iodide (56 mg, 0.219 mmol) in
methanol (40 mL) was stirred, whereupon the platinum complex
quickly dissolved giving an orange solution. After 15 min. the
solution was filtered to remove a trace of insoluble matter, and
NH4PF6 (300 mg, excess) was added to the filtrate to give an orange
precipitate. Water (5 mL) was added to assist precipitation, the
product filtered, washed with water (2 Â 10 mL) and dried under
vacuum to give 210 mg (64%) of 2ÁPF6. ESI MS m/z 1597.17,
The nitrogen was restrained to approximate isotropic behav-
iour. Its proximity to two heavy Pt centres results in a non-positive
definite thermal parameter. Further support for the presence of a
NH2 group is the location of the amide hydrogens at reasonable
positions from a difference Fourier map. NH2 hydrogen atoms were
fixed at their observed locations.
[Pt2(
l
-S)(
l
-I)(PPh3)4]+ (100%), m/z 1506.24, [Pt2(
l-S)(l-Cl)
(PPh3)4]+ (3%), m/z 798.15, [Pt2( -I)(PPh3)4]2+ (5%). The com-
l-SH)(l
pound was further characterised by 31P{1H} NMR spectroscopy,
giving parameters as previously reported [13].
Crystal data for C100H92BNOP4Pt2S; Mr = 1880.67; monoclinic; space
group P21/n; a = 13.834(2) Å; b = 19.729(3) Å; c = 30.971(5) Å;
4.7. Synthesis of [Pt2(
l
-S)(
l
-I)(PPh3)4]I (2ÁI)
a
= 90°; b = 96.186(2)°;
k(Mo K ) = 0.71073 Å;
201654 reflections collected; 21050 unique (Rint = 0.0379); giving
R1 = 0.0219, wR2 = 0.0466 for 18374 data with [I > 2 (I)] and
c
= 90°; V = 8404(2) Å3; Z = 4; T = 120(2) K;
a
l(Mo Ka ;
) = 3.476 mmÀ1; dcalc = 1.486 g cmÀ3
A suspension of [Pt2(
l
-S)2(PPh3)4] (295 mg, 0.196 mmol) and
2-chloro-1-methylpyridinium iodide (90 mg, 0.352 mmol, excess)
in methanol (30 mL) was stirred, whereupon the Pt complex ap-
peared to react and dissolve, and a new orange suspension quickly
formed. After stirring for 5 min., solid KI (300 mg, 1.81 mmol) was
added with no further visible change. After stirring for 20 min. the
resulting yellow-orange suspension was filtered, washed with
methanol (5 mL) and then water (5 mL) and dried under vacuum
to give 2ÁI as an orange solid (265 mg, 78%). Found: C, 49.20; H,
3.67; N, 0.00. C72H60I2P4Pt2S requires C, 50.11; H, 3.51; N, 0.00%.
r
R1 = 0.0299, wR2 = 0.0492 for all 21050 data. Residual electron den-
sity (eÀ ÅÀ3) maximum/minimum: 1.892/À0.715.
Acknowledgements
The Universities of Waikato and Notre Dame are acknowledged
for financial support of this work. W.H. thanks Pat Gread and
Wendy Jackson for mass spectrometry assistance and technical
support and Professor Paul Low (University of Durham, UK) for
ESI MS m/z 1597.17, [Pt2(l-S)(l
-I)(PPh3)4]+ (100%). The complex
Henderson, William
