Organometallics
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−8.9 (s, 10B, B7−11), −11.4 (s, 10B, B2−6). 199Hg{1H} NMR
(CD3CN, δ ppm): −1340 (s). (−)-MALDI-MS m/z (isotopic
abundance > 60) calcd for 3 ([C2B22Cl22Hg]−): 1497(61),
1499(81), 1501(85), 1502(81), 1503(100), 1504(71), 1505(84).
Found: 1497(65), 1499(80), 1501(80), 1502(78), 1503(100),
1504(75), 1505(86). Cs23: Anal. Calcd for C2B22Cl22Cs2Hg: C, 1.59.
Found: C, 1.51. [Et4N]23: Anal. Calcd for C18H40B22Cl22HgN2: C,
14.39; H, 2.68; N, 1.86. Found: C, 15.06; H, 3.12; N, 1.51.
Synthesis of Cs2[Hg(closo-1-CB11Cl11)2] (Cs23). Method B.
Cs[1-H-closo-1-CB11Cl11] (260 mg, 0.4 mmol) and 5 equiv of KOH
were dissolved in methanol (10 mL), and subsequently, HgCl2 (54
mg, 0.2 mmol) was added to the clear solution. The reaction mixture
was refluxed for 12 h. After cooling to room temperature, deionized
water (50 mL) was added and most of the methanol was removed at a
rotary evaporator. Dropwise addition of a solution of CsCl (2.00 g,
11.88 mmol) in water (10 mL) resulted in the precipitation of pure
Cs23 as a colorless solid. Yield: 226 mg (0.15 mmol, 76%).
421(100), 422(81). Anal. Calcd for C15H36B11HgN: C, 32.76; H, 6.60;
N, 2.55. Found: C, 32.91; H, 6.72; N, 2.35.
Synthesis of Cs[PhHg(closo-1-CB11Cl11)] (Cs8). The synthesis
of Cs8 was performed similarly to the preparation of [Et4N]6 starting
from Cs[1-H-closo-1-CB11Cl11] (200 mg, 0.38 mmol) and PhHgCl
(131 mg, 0.42 mmol). However, a solution of CsCl (2 g, 11.88 mmol)
in water (5 mL) was slowly added to an aqueous solution of the crude
product, resulting in the precipitation of an off-white solid. Crude Cs8
was dissolved in acetone and filtered. Chloroform (50 mL) was added,
and the acetone was removed at a rotary evaporator. Colorless, pure
Cs8 precipitated from the solution at 5 °C overnight. Yield: 196 mg
1
(0.21 mmol, 55%). H{11B} NMR (CD3CN, δ ppm): 7.5−7.0 (m,
phenyl). 13C{1H} NMR (CD3CN, δ ppm): 155.4 (s, 1C, 1J(199Hg,13C)
= 1837 Hz, Cipso), 137.3 (s, 2C, 2J(199Hg,13C) = 108 Hz, Cortho), 130.4
(s, 1C, 4J(199Hg,13C) = 28 Hz, Cpara), 129.9 (s, 2C, 3J(199Hg,13C) = 156
1
Hz, Cmeta), 85.2 (s, 1C, J(199Hg,13C) = 936 Hz, Ccluster). 11B NMR
(CD3CN, δ ppm): −3.8 (s, 1B, B12), −9.2 (s, 5B, B7−11), −11.6 (s,
5B, B2−6). 199Hg{1H} NMR (CD3CN, δ ppm): −1057 (s).
(−)-MALDI-MS m/z (isotopic abundance > 60) calcd for 8
([C7H5B11Cl11Hg]−): 795(89), 796(92), 797(80), 798(100),
799(65), 800(87). Found: 795(86), 796(95), 797(75), 798(100),
799(69), 800(91). Anal. Calcd for C7H5B11Cl11CsHg: C, 9.03; H, 0.54.
Found: C, 9.95; H, 0.57.
Preparation of Cs2[Hg(closo-1-CB11Br11)2] (Cs24). The syn-
thesis of Cs24 was accomplished by both methods described for the
preparation of Cs23.
Method A. Cs[1-H-closo-1-CB11Br11] (300 mg, 0.26 mmol) was
n
treated with BuLi in hexane (0.18 mL, 1.6 mol L−1, 0.28 mmol) at 0
°C, followed by the addition of HgCl2 (35 mg, 0.13 mmol). Yield: 270
mg (0.11 mmol, 83%).
Synthesis of Cs[PhHg(closo-1-CB11Br11)] (Cs9). Cs9 was
prepared as described for Cs8 using Cs[1-H-closo-1-CB11Br11] (250
mg, 0.22 mmol) and PhHgCl (75 mg, 0.24 mmol) as starting
Method B. Cs[1-H-closo-1-CB11Br11] (550 mg, 0.48 mmol) was
reacted with HgCl2 (65 mg, 0.24 mmol) in basic methanol. Yield: 507
mg (0.20 mmol, 85%). 13C{1H} NMR (CD3CN, δ ppm): 85.7 (s,
1J(199Hg,13C) = 1930 Hz, Ccluster). 11B NMR (CD3CN, δ ppm): −3.8
(s, 2B, B12), −9.2 (s, 10B, B7−11), −11.6 (s, 10B, B2−6). 199Hg
NMR (CD3CN, δ ppm): −1311 (s). (−)-MALDI-MS m/z (isotopic
abundance > 60) calcd for 4 ([C2B22Br22Hg]−): 2216(65), 2217(84),
2218(84), 2219(95), 2220(98), 2221(90), 2222(100), 2223(84),
2224(76), 2225(68), 2226(66). Found: 2216(60), 2217(82),
2218(80), 2219(95), 2220(95), 2221(86), 2222(100), 2223(89),
2224(80), 2225(75), 2226(69). Anal. Calcd for C2B22Br22Cs2Hg: C,
0.97. Found: C, 1.35.
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materials. Yield: 240 mg (0.17 mmol, 76%). H{11B} NMR (CD3CN,
δ ppm): 7.4−7.0 (m, phenyl). 13C{1H} NMR (CD3CN, δ ppm): 155.4
1
2
(s, 1C, J(199Hg,13C) = 1844 Hz, Cipso), 137.2 (s, 2C, J(199Hg,13C) =
109 Hz, Cortho), 130.5 (s, 1C, J(199Hg,13C) = 28 Hz, Cpara), 129.9 (s,
4
2C, J(199Hg,13C) = 155 Hz, Cmeta), 93.0 (s, 1C, J(199Hg,13C) = 987
Hz, Ccluster). 11B NMR (CD3CN, δ ppm): −4.3 (s, 1B, B12), −8.6 (s,
5B, B7−11), −11.8 (s, 5B, B2−6). 199Hg{1H} NMR (CD3CN, δ
ppm): −1002 (s). (−)-MALDI-MS m/z (isotopic abundance > 60)
calcd for 9 ([C7H5B11Br11Hg]−): 1283(64), 1284(68), 1285(62),
1286(100), 1287(97), 1288(99), 1289(83), 1290(94), 1291(76),
1292(65). Found: 1283(65), 1284(71), 1285(66), 1286(100),
1287(99), 1288(100), 1289(85), 1290(97), 1291(77), 1292(64).
Anal. Calcd for C7H5B11Br11CsHg: C, 5.92; H, 0.35. Found: C, 5.85;
H, 0.36.
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1
Preparation of [Et4N][PhHg(closo-1-13CB11H11)] ([Et4N]6). A
70 mL glass finger equipped with a valve with a PTFE stem (Young,
London), fitted with a PTFE-coated magnetic stirring bar, was charged
with Cs[1-H-closo-1-13CB11H11] (100 mg, 0.36 mmol) and tetrahy-
n
drofuran (20 mL). After addition of a solution of BuLi in hexane
Synthesis of Cs[PhHg(closo-1-CB11I11)] (Cs10). In analogy to
the synthesis described for Cs8, the cesium salt of anion 10 was
prepared from Cs[1-H-closo-1-CB11I11] (300 mg, 0.18 mmol) and
PhHgCl (63 mg, 0.20 mmol). Yield: 290 mg (0.15 mmol, 83%).
1H{11B} NMR (CD3CN, δ ppm): 7.4−7.0 (m, phenyl). 13C{1H}
NMR (CD3CN, δ ppm): 148.0 (s, 1C, 1J(199Hg,13C) = 1803 Hz,
(0.25 mL, 1.6 mol L−1, 0.40 mmol) at 0 °C, the reaction mixture was
warmed to room temperature and stirred for 1 h. A solution of
PhHgCl (126 mg, 0.40 mmol) in THF (15 mL) was added, and the
resulting mixture was stirred for a further 2 h. The reaction mixture
was poured into water (50 mL), the THF was removed using a rotary
evaporator, and the aqueous phase was filtered. A solution of [Et4N]Br
(1.50 g, 7.14 mmol) in H2O (30 mL) was added slowly under stirring.
The white precipitate that had formed was isolated by filtration. The
crude product that contained a small amount of Cs[1-H-closo-
1-13CB11H11] was dried in a vacuum and dissolved in acetonitrile, and
the solution was filtered. The volume of the clear acetonitrile solution
was reduced to approximately 5 mL, and addition of diethyl ether (100
mL) resulted in the precipitation of [Et4N]6 as a white solid, which
was filtered off, and dried in a vacuum. Yield: 169 mg (0.31 mmol,
85%). NMR data for anion 6: 1H{11B} NMR (CD3CN, δ ppm): 7.5−
7.1 (m, 5H, phenyl), 1.69 (s, 5H, 3J(199Hg,1H) = 44 Hz, BH2−6), 1.59
(s, 5H, BH7−11), 1.21 (s, 1H, BH12). 13C{1H} NMR (CD3CN, δ
2
Cipso), 137.3 (s, 2C, J(199Hg,13C) = 105 Hz, Cortho), 130.2 (s, 1C,
3
4J(199Hg,13C) ∼ 22 Hz, Cpara), 129.5 (s, 2C, J(199Hg,13C) = 153 Hz,
C
meta), 103.0 (s, 1C, 1J(199Hg,13C) = 1092 Hz, Ccluster). 11B NMR
(CD3CN, δ ppm): −9.9 (s, 1B, B12), −11.4 (s, 5B, B7−11), −16.5 (s,
5B, B2−6). 199Hg{1H} NMR (CD3CN, δ ppm): −865 (s).
(−)-MALDI-MS m/z (isotopic abundance > 60) calcd for 10
([C7H5B11HgI11]−): 1804(77), 1805(74), 1806(100), 1807(80).
Found: 1804(80), 1805(77), 1806(100), 1807(82). Anal. Calcd for
C7H5B11CsHgI11: C, 4.34; H, 0.26. Found: C, 4.68; H, 0.38.
Attempted Synthesis of Cs[C6F5Hg(closo-1-CB11X11)] (X = H,
F, Cl, Br, I). The reactions were performed similar to the syntheses of
the Cs+ and [Et4N]+ salts of the anions 6 and 8−10. The solution of
C6F5HgCl in THF was added either at 0 °C or at −78 °C to a solution
of the corresponding Li+/Cs+ salt of the carboranyl ligand in THF.
The NMR spectroscopic and mass spectrometric ((−)-ESI and
(−)-MALDI) analyses showed no differences for the reactions
performed at the two different temperatures. According to the 11B
and 19F NMR spectroscopic data of the reaction mixtures, the main
products (>90%) of the reactions are Hg(C6F5)2 and the dianions 1−4
and a complex mixture of {closo-1-CB11I11} derivatives, which probably
contain some carba-closo-dodecaboranyl mercury(II) complexes, in the
case of the iodinated carba-closo-dodecaborate cluster, respectively.
2
1
ppm): 165.8 (d, 1C, J(13C,13C) = 37.4 Hz, J(199Hg,13C) = 1332 Hz,
Cipso), 138.8 (s, 2C, J(199Hg,13C) = 92 Hz, Cortho), 129.1 (d, 2C,
2
4J(13C,13C) = 2.0 Hz, J(199Hg,13C) = 112 Hz, Cmeta), 128.9 (s, 1C,
3
4J(199Hg,13C) = 19 Hz, Cpara), 87.3 (s, 1C, J(199Hg,13C) = 1150 Hz,
1
2J(13C,13C) = 37 Hz, Ccluster). 11B NMR (CD3CN, δ ppm): −5.0 (d,
1B, J(11B,1H) = 133 Hz, B12), −11.5 (d, 5B, J(11B,1H) = 135 Hz,
1
1
B7−11), −13.8 (d, 5B, 1J(11B,1H) = 149 Hz, B2−6). 199Hg{1H} NMR
(CD3CN, δ ppm): −917 (s, J(199Hg,13C) = 1139 Hz). (−)-MALDI-
1
MS m/z (isotopic abundance > 60) calcd for 6 ([C7H16B11Hg]−):
419(83), 420(100), 421(100), 422(84). Found: 419(85), 420(97),
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dx.doi.org/10.1021/om201023h | Organometallics 2012, 31, 1566−1577