FULL PAPER
Complex 6: The dithiosemicarbazone ligand
3
(0.0401 g,
chromatography. The aqueous layer was transferred to a clean
Schlenk tube for the next reaction cycle.
0.059 mmol) was suspended in 1:1 water/ethanol mixture
a
(20 mL). To this was added, an equimolar amount of sodium hy-
dride and two equivalents of [PdCl2(PTA)2] (0.0574 g, 0.118 mmol)
in 10 mL of ethanol. The solution was left to reflux at 80 °C over-
night. The orange brown mixture formed was filtered using a
Hirsch funnel and washed with cold ethanol and dried under vac-
uum to afford the desired product as powder, yield, 0.062 g (64%);
no m.p., decomposition without melting at 268 °C. FT-IR (KBr):
Acknowledgments
The authors greatly acknowledge the financial support from the
University of Cape Town, the Department of Science and Technol-
ogy, South Africa, the Canon Collins Trust, the NRF South Africa/
China bilateral fund and the NRF Department of Science and
Technology (DST), Centre of Excellence in Catalysis (c*change).
Generous donation of palladium chloride from Anglo-Platinum
Corporation/Johnson Matthey Limited is gratefully acknowledged.
ν = 1603, 1599 (C=N), 943 (C–S) cm–1. 1H NMR (300 MHz; [D ]-
˜
6
4
DMSO): δ = 9.49 (s, 2 H, CNHC), 8.65 (d, JP-H = 13.0 Hz, 2 H,
Himine), 7.80 (d, JH-H = 2.2 Hz, 2 H, HAr), 7.66 (s, 4 H, HAr), 7.54
3
(dd, 3JH-H = 8.7, 4JH-H = 2.2 Hz, 2 H, HAr), 6.84 (d, 3JH-H = 8.6 Hz,
2 H, HAr), 4.68 (m, 12 H, PTA), 4.39 (s, 12 H, PTA) ppm. 13C{1H}
NMR (75 MHz; [D6]DMSO): δ = 162.6, 155.5, 146.5, 136.4, 132.7,
124.7, 115.9, 1.9.8, 71.5, 52.2. 31P{1H} NMR (162 MHz; [D6]-
DMSO): δ = –37.4 ppm. C34H38N12Na2O8P2Pd2S4·12H2O: calcd.
C 29.00, H 4.44, N 11.94, S 9.11; found C 28.73, H 4.72, N 11.29,
S 9.75. ESI-MS (negative): m/z = 573 [M]2–, where M is the anion;
S20 °C = 7 mg/mL in water.
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Complex 7: The dithiosemicarbazone ligand
3
(0.113 g,
0.168 mmol) was suspended in ethanol (20 mL). To this, an equi-
molar amount of sodium hydride was added and the mixture was
left to stir at room temperature for 2 h. [PdCl2(PPh3)2] (0.236 g,
0.336 mmol) was suspended in 10 mL of ethanol and this was
added to the ligand. This was left to stir at room temperature over-
night. The yellow precipitate formed was filtered using a Hirsch
funnel and washed with ethanol and dried under vacuum, yield,
0.219 g (93%); no m.p., decomposition without melting at 332 °C.
FT-IR (KBr): ν = 1601, 1596 (C=N), 937 (C–S) cm–1. 1H NMR
˜
4
(300 MHz; [D6]DMSO): δ = 9.33 (s, 2 H, NNCH), 8.65 (d, JP-H
= 13.8 Hz, 2 H, Himine), 7.77 (d, JH-H = 2.2 Hz, 2 H, HAr), 7.70–
3
7.50 (m, 34 H, Ar), 7.41 (dd, 3JH-H = 8.7, 4JH-H = 2.2 Hz, 2 H, HAr),
6.48 (m, 2 H, HAr) ppm. 13C{1H} NMR (75 MHz; [D6]DMSO): δ
= 162.4, 152.4, 151.3, 136.3, 134.6, 133.9–130.1, 129.6, 124.7, 119.2,
116.5, 46.3 ppm. 31P{1H} NMR (162 MHz; [D6]DMSO): δ =
24.4 ppm. C58H44N6Na2O8P2Pd2S4·5H2O: calcd. C 46.69, H 3.65,
N 5.63, S 8.60; found C 46.21, H 3.73, N 5.21, S 8.96. ESI-MS
(negative): m/z = 678 [M]2–, where M is the anion; S20 °C = 4.5 mg/
mL in water.
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General Suzuki–Miyaura Cross-Coupling Procedure: Each catalyst
precursor (1.00 mol-%), phenylboronic acid (0.80 mmol), aryl hal-
ide (0.50 mmol), tetrabutylammonium bromide (0.25 mmol), base
(1.00 mmol) and water (2 mL) were placed in a 50 mL Schlenk
tuve. The mixture was heated to the appropriate temperature and
the reaction left to proceed at this temperature for 24 h in air. The
products were extracted with toluene and analysed using gas
chromatography. Conversions reported are an average of two iden-
tical reactions and was based on the aryl halide.
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dron Lett. 2013, 54, 4914.
For NMR spectroscopy determination, the reaction was cooled
and ethyl acetate (2 mL) added. The organic layer was dried with
magnesium sulfate and the product formed was recovered after sep-
aration on a short column using petroleum ether/ethyl acetate sol-
vent mixture. The recovered product was dried under vacuum.
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Tetrahedron Lett. 2013, 54, 154; b) D. A. Alonso, C. Nájera,
M. C. Pacheco, Org. Lett. 2000, 2, 1823; c) D. A. Alonso, C.
Nájera, M. C. Pacheco, Adv. Synth. Catal. 2002, 344, 172; d)
L. Botella, C. Nájera, Angew. Chem. Int. Ed. 2002, 663, 46; e)
D. Zim, A. S. Gruber, G. Ebeling, J. Dupont, A. L. Monteiro,
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Tetrahedron 2014, 70, 5980.
Catalyst Recycling Procedure: A Schlenk tube was charged with
catalyst 4 (1.00 mol-%), phenylboronic acid (0.80 mmol), aryl hal-
ide (0.50 mmol), tetrabutylammonium bromide (0.25 mmol), so-
dium carbonate (1.00 mmol) and water (2 mL). The mixture was
heated to 70 °C and the reaction was left to proceed at this tem-
perature for 24 h in air. The reaction mixture was cooled to room
temperature and 2 mL of toluene added and this was stirred for
5 min. The organic layer was separated and analysed using gas
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Eur. J. Inorg. Chem. 2015, 4088–4094
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