membered chelate rings with relatively long Pb–O bonds. In
ongoing studies of tin() complexes with this type of ligand19
the same co-ordination behaviour is observed, and the five-
co-ordinate [Sn(CH3)2Br{S2CP(O)(CH2Ph)2}] even has a com-
pletely planar chelate ring (crystallographic mirror plane).
The correlation between co-ordination number and the above
mentioned magnitudes of the NMR coupling constants to the
metal atom is also found in these tin() complexes.
colourless to red-brown. KOH pellets (10 g) were added as a
drying agent, and the mixture was stirred for 1 h after which the
aqueous KOH phase was removed with a syringe. Pyridine
(70 ml) was added, the solution filtered and the thf removed
by rotary evaporation. The red-brown pyridine solution was
treated with diethyl ether (120 ml) and kept overnight at Ϫ6 ЊC.
The orange precipitate was filtered off in air, washed with
diethyl ether–thf (3:1) and dried in vacuo. Yield: 19.8 g, 53%.
Calc. for C15H14KOPS2: C, 52.30; H, 4.10. Found: C, 52.40;
H, 4.17%.
Experimental
[PPh4][Ph2P(O)CS2]ؒ0.5H2O.
Tetraphenylphosphonium
NMR spectra were recorded on a Bruker AC-250 spectrometer
operating at 250.133, 101.256 and 62.896 MHz for 1H, 31P-{1H}
and 13C-{1H} respectively. The deuteriated solvent served as the
lock in the 1H and 13C measurements with tetramethylsilane as
internal reference. The 31P NMR spectra were calibrated
against an external 85% H3PO4 aqueous solution. The high
frequency positive convention was used for all chemical shifts.
The infrared spectra were obtained with a Perkin-Elmer 283
spectrophotometer in the range 4000–200 cmϪ1 using KBr/CsI
pellets, UV/vis spectra on Ultraspec3000 or Perkin-Elmer
Lambda17 spectrophotometers. Elemental analyses were
carried out on a Carlo Erba Strumentazione model 1106 ana-
lyser. A STOE Stadi P X-ray powder diffractometer was used to
obtain powder diffraction data with Cu-Kα1 radiation selected
by a curved germanium monochromator. Data were collected
from 5 to 40Њ (2θ) in 0.01Њ intervals using a position sensitive
detector covering 7Њ in 2θ. The software STOE WinXPOW
(version 1.05, 1999) supplied with the instrument was used for
the data treatment.
bromide (0.419 g, 1.00 mmol) was added to a stirred suspension
of KL1 (0.405 g, 1.00 mmol) in CH2Cl2 (10 ml). The solution
changed from colourless to wine-red instantaneously and a
white precipitate (KBr) formed. After filtration or centrifug-
ation the solvent was removed at once by rotary evaporation.
The oily salmon pink solid was dissolved in acetonitrile (10 ml),
and the wine-red solution treated with diethyl ether until turbid
and stored at 5 ЊC for 20 h. The resulting red-brown crystalline
product was filtered off in air, washed with diethyl ether and
dried in vacuo. Yield: 0.323 g, 79%. Calc. for C37H31O1.5P2S2:
C, 71.02; H, 4.99. Found: C, 70.96; H, 5.00%.
[PPh4][(PhCH2)2P(O)CS2]. This compound was isolated in
a similar way from KL2 and PPh4Br as red-brown crystals.
Yield: ca. 70%. Calc. for C39H34OP2S2: C, 72.64; H, 5.32.
Found: C, 72.89; H, 5.20%.
[PbPh2{S2CP(O)Ph2}2] 1a. Method (a). A solution of KL1
(0.570 g, 1.41 mmol) in acetone (25 ml) was added dropwise
PbPh2Cl2, PbPh3Cl and PbPh4 were purchased from Ventron
Corporation and used as such after vacuum drying. PbPh2Br2
and PbPh2I2 were obtained by treating a solution of PbPh4
in chloroform with chloroform solutions of Br2 and I2, respec-
tively, in a 1:2 molar ratio. Ph2P(O)H8 and (PhCH2)2P(O)H7
were prepared by published methods. Solvents were purified by
standard procedures. Anhydrous solvents were purchased from
Aldrich and used as received.
to a stirred suspension of PbPh2
Cl (0.300 g, 0.694 mmol) in
2
acetone (10 ml). After the mixture had been stirred for 20 min
a violet solid had formed in a wine-red solution. The powder
was filtered off in air, washed with acetone, water and methanol
and dried in vacuo. Yield: 0.340 g, 54%. Recrystallization from
dichloromethane–hexane gave crystals suitable for single crystal
X-ray diffraction. Calc. for C38
H30O2P2PbS4: C, 49.82; H, 3.30.
Found: C, 49.61; H, 3.26%.
Method (b). PbPh2Cl2 (0.120 g, 0.278 mmol) was added to
a stirred suspension of KL1 (0.224 g, 0.554 mmol) in CH2Cl2
(5 ml). The solution changed from colourless to dark blue
instantaneously and a white precipitate (KBr) formed, which
was removed by centrifugation. Diethyl ether (5 ml) was added
to the solution, and the mixture kept at Ϫ5 ЊC overnight, after
which the resulting violet crystalline product was filtered off
in air, washed with dichloromethane–diethyl ether (1:1) and
dried in vacuo. Yield: 0.194 g, 76%. All spectroscopic data
for complex 1a prepared in this way are identical with those
obtained by method (a).
Preparations
The following syntheses of the potassium and tetraphenyl-
phosphonium salts of the ligands are modifications of earlier
procedures3b,c primarily concerning the choice of solvent and
time of reaction.
K[Ph2P(O)CS2]ؒC4H8O2 (KL1).
A stirred solution of
Ph2P(O)H (20.95 g, 0.1036 mol) in thf (200 ml) was cooled
to Ϫ6 ЊC and treated with CS2 (8.68 g, 0.114 mol) and sub-
sequently with an aqueous solution of 14.14 M KOH (7.33 ml,
0.1036 mol). This mixture was stirred vigorously for 45 min,
while it changed from colourless to red-brown. The solvent was
removed by rotary evaporation and the red-brown oil dissolved
in 1,4-dioxane (150 ml). The solution was stirred overnight at
room temperature, and a red-orange precipitate was formed.
Diethyl ether (120 ml) was added and the mixture cooled to
Ϫ6 ЊC after which the precipitate was filtered off in air and
dried in vacuo. Crude yield: 24.0 g, 57%. The potassium salt was
recrystallized by dissolving the solid in acetonitrile (ca. 200 ml),
filtering the red solution and adding 1,4-dioxane (100 ml) and
diethyl ether (200 ml). The resulting red-orange powder
was filtered off, washed with 1,4-dioxane–diethyl ether (1:1)
and dried in vacuo. Yield: 19.0 g, 45%. Calc. for C13H10KOP-
S2ؒC4H8O2: C, 50.47; H, 4.48. Found: C, 50.50; H, 4.38%.
[PbPh2{S2CP(O)(CH2Ph)2}2] 1b. Method (a). A solution of
KL2 (0.344 g, 1.00 mmol) in acetone (18 ml) was added drop-
wise over 30 min to a stirred suspension of PbPh2Cl2 (0.216 g,
0.500 mmol) in acetone (8 ml). After the mixture had been
stirred for 10 min a red-brown solid had formed in a red-brown
solution. Diethyl ether (10 ml) was added and the mixture
stirred for 15 min, after which the product was filtered off in air,
washed with acetone–diethyl ether (1:1), water and methanol
and dried in vacuo. Yield: 0.433 g, 89%. Recrystallization from
dichloromethane–hexane gave purple-red crystals. Calc. for
C42H38O2P2PbS4: C, 51.89; H, 3.94. Found: C, 51.38; H, 3.88%.
Method (b). A solution of (PPh4)L2 (0.330 g, 0.511 mmol)
in dichloromethane (10 ml) was added dropwise over 5 min
to a stirred suspension of PbPh2Cl2 (0.111 g, 0.257 mmol) in
dichloromethane (7 ml). Methanol (25 ml) was added to the
clear, orange-red solution and the dichloromethane removed
by rotary evaporation. The solution turned wine-red and a
precipitate started to form. After 20 hours the purple-red
crystalline precipitate was collected by filtration, washed with
K[(PhCH2)2P(O)CS2] (KL2).
A
stirred solution of
(PhCH2)2P(O)H (25.08 g, 0.1089 mol) in thf (250 ml) was
treated with CS2 (9.12 g, 0.120 mol) and subsequently with an
aqueous solution of 14.14 M KOH (8.47 ml, 0.1089 mol). This
mixture was stirred vigorously for 20 h, while it changed from
4366
J. Chem. Soc., Dalton Trans., 2000, 4360–4368
Olafsson, Sigurjoen Norbcrg
