P. Tokarz et al. / Journal of Organometallic Chemistry xxx (2015) 1e10
9
5.3.1. [closo-B12H11-1-IPh]ꢀ [NEt4]þ (1a[NEt4])
1B). Anal. Calcd. for C13H36B12N2: C, 44.59; H, 10.36; N, 8.00. Found:
C, 44.85; H, 10.55; N, 7.97.
1
Yield 88%; H NMR (300 MHz, CD3CN, ꢀ20 ꢂC)
d 0.2e2.3 (br m,
11H), 1.15 (tt, J1 ¼7.2 Hz, J2 ¼ 1.8 Hz, 12H), 3.10 (q, J ¼ 7.3 Hz, 8H), 7.37
A similar procedure using the phenyliodonium derivative
(t, J ¼ 7.8 Hz, 2H), 7.58 (t, J ¼ 7.4 Hz, 1H), 7.79 (d, J ¼ 9.2 Hz, 2H); 13
C
1a[NEt4] gave pyridinium 3[NEt4] in 12% yield. In addition, during
chromatographic separation a second more polar oily fraction was
isolated consisting of insertion product of [closo-B12H11-1-
(C6H4I)]2ꢀ: HRMS, calcd for [B12H15C6I]2ꢀ m/z ¼ 173.0673, found m/
z ¼ 173.0701.
NMR (76 MHz, CD3CN, ꢀ20 ꢂC)
d
7.4, 52.4 (t, J ¼ 3.0 Hz), 131.6, 131.9,
137.1; {1H} 11B (96 MHz, CD3CN, ꢀ20 ꢂC)
d
ꢀ14.9 (6B), ꢀ14.3 (6B).
5.3.2. [closo-B12H11-1-(IC6H4OMe-4)]ꢀ [NEt4]þ (1b[NEt4])
Yield 95%; 1H NMR (300 MHz, CD3CN, ꢀ20 ꢂC)
d 0.2e2.3 (br m,
11H), 1.16 (tt, J1 ¼7.3 Hz, J2 ¼1.7 Hz, 12H), 3.11 (q, J¼ 7.3Hz, 8H), 3.79(s,
5.6. Preparation of [closo-B12H11-1-NC5H5]ꢀ [NHEt3]þ (3[NHEt3])
3H), 6.91 (d, J ¼ 9.1 Hz, 2H), 7.66 (d, J ¼ 9.1 Hz, 2H); 13C NMR (76 MHz,
CD3CN, ꢀ20 ꢂC)
d
7.4, 52.5 (t, J ¼ 3.0 Hz), 56.0, 92.5,117.5,138.4,162.2;
The salt was obtained in 41% yield from 1b[NHEt3] according to
the procedure for the preparation of 3[NEt4]: mp 198e200 ꢂC; 1H
{1H} 11B (96 MHz, CD3CN, ꢀ20 ꢂC)
ꢀ15.1 (6B), ꢀ14.2 (6B).
d
NMR (500 MHz, CD3CN)
d
0.6e2.0 (br, m, 11H), 1.23 (t, J ¼ 7.3 Hz,
5.3.3. [closo-B12H11-1-(IC6H4OMe-4)]ꢀ [NHEt3]þ (1b[NHEt3])
9H), 3.14 (qd, J1 ¼ 7.3 Hz, J2 ¼ 5.1 Hz, 6H), 6.50 (br t, J ¼ 53 Hz, 1H),
7.65 (t, J ¼ 6.8 Hz, 2H), 8.17 (tt, J1 ¼ 7.6 Hz, J2 ¼ 1.4 Hz, 1H), 9.01 (d,
Yield 74%; 1H NMR (300 MHz, CD3CN, ꢀ20 ꢂC)
d 0.2e2.3 (br m,
11H), 1.19 (t, J ¼ 7.3 Hz, 9H), 3.10 (qd, J1 ¼ 7.3 Hz, J2 ¼ 5.1 Hz, 6H),
3.79 (s, 3H), 6.55 (br t, J ¼ 52 Hz, 1H), 6.91 (d, J ¼ 9.0 Hz, 2H), 7.66 (d,
J ¼ 5.6 Hz, 2H); 13C NMR (126 MHz, CD3CN)
d 9.2, 48.1, 126.8, 143.3,
147.4. Anal. calcd. for C11H32B12N2: C, 41.02; H, 10.01; N, 8.70.
Found: C, 41.30; H, 10.13; N, 8.54.
J ¼ 9.0 Hz, 2H); 13C NMR (76 MHz, CD3CN, ꢀ20 ꢂC)
d 8.9, 47.4, 56.0,
92.5, 117.5, 138.5, 162.3; {1H} 11B (96 MHz, CD3CN, ꢀ20 ꢂC)
(6B), ꢀ14.2 (6B).
d
ꢀ14.9
5.7. Preparation of [closo-B12H11-1-S(CH2)5]ꢀ [NEt4]þ (8[NEt4])
5.4. Preparation of [closo-B12H11-1-SCHNMe2]ꢀ [NEt4]þ (2[NEt4])
[closo-B12H12-SCHNMe2][NEt4] (2[NEt4], 270 mg, 0.75 mmol)
was dissolved in MeCN (10 mL), [NEt4]þOHꢀ (35% in water, 947 mg,
N,N-Dimethylthioformamide (10 mL) was cooled to ꢀ10 ꢂC in an
ice-salt bath and 4-methoxyphenyliodonium derivative 1b[NEt4]
(2.56 g, 5.0 mmol) was added in portions over 15 min. The mixture
was stirred at ꢀ5 ÷ ꢀ10 ꢂC overnight. All volatiles were removed
under vacuum (0.1 mm Hg) and the viscous oily residue was treated
with CH2Cl2 (3 mL). After two hours of stirring the resulting pre-
cipitate was collected by filtration and washed with CH2Cl2 giving
350 mg of off-white solid. The filtrate was evaporated under
reduced pressure and treated again with a small portion of CH2Cl2,
stirred for two hours, filtrated and the resulting solid was washed
with CH2Cl2 giving 130 mg of off-white solid. The solids were
combined giving 480 mg (27% yield) of the protected mercaptan
2[NEt4], which was used for further transformations without
additional purifications. An analytical sample was obtained by
purification using preparative thin layer chromatography (CH2Cl2/
MeCN, 10:3): mp 372 ꢂC (decomp.); 1H NMR (500 MHz, CD3CN)
2.25 mmol) was added, followed by a solution of 1,5-
dibromopentane (173 mg, 0.75 mmol) in acetonitrile (10 mL). The
solution was gently refluxed overnight and evaporated to dryness
in vacuo. The residue was suspended in water. The resulting white
solid was collected by filtration and washed several times with
water and hexane, giving 280 mg of crude product. The product was
further crystallized from MeOH giving 230 mg (82% yield) of sul-
fonium 8[NEt4] as white crystals: mp 238e240 ꢂC; 1H NMR
(500 MHz, CD3CN)
d
0.6e1.8 (br, m, 11H), 1.97 (tt, J1 ¼ 7.3 Hz,
J2 ¼ 2.8 Hz,12H),1.39 (qt, J1 ¼12.8 Hz, J2 ¼ 3.6 Hz, 2H),1.62e1.78 (m,
2H), 2.09 (dm, J ¼ 15.3 Hz, 2H), 2.79 (td, J1 ¼13.0 Hz, J2 ¼ 2.4 Hz, 2H),
3.01 (br d, J ¼ 13.9 Hz, 2H), 3.15 (q, J ¼ 7.2 Hz, 8H); 13C NMR
(126 MHz, CD3CN)
(160 MHz, CD3CN)
d
7.7, 24.8, 25.0, 39.1, 53.0 (t, J ¼ 11 Hz); 11B
d
ꢀ15.5 (d, J ¼ 126 Hz, 5B), ꢀ13.9 (d, J ¼ 132 Hz,
5B), ꢀ13.30 (d, 1B), ꢀ10.1 (s, 1B). Anal. Calcd. for C13H36B12N2: C,
41.83; H, 11.07; N, 3.75. Found: C, 41.91; H, 11.08; N, 3.75.
d
0.5e1.8 (br m, 11H), 1.18 (t, J ¼ 7.3 Hz, 12H), 3.13 (q, J ¼ 7.3 Hz, 8H),
3.19 (s, 3H), 3.39 (s, 3H), 9.18 (s, 1H); 13C NMR (126 MHz, CD3CN)
7.7, 41.7, 48.8, 53.0, 187.0; 11B (160 MHz, CD3CN)
ꢀ15.2 (d,
5.8. Kinetic measurements
d
d
1H), ꢀ14.0 (d, J ¼ 129 Hz, 10B), ꢀ8.9 (s, 1B). Anal. Calcd. for
The decomposition of iodonium zwitterions 1[NEt4] in CD3CN at
C
C
11H38B12N2S: C, 36.68; H, 10.63; N, 7.78. Anal. Calcd. for
11H38B12N2S$1/2CH2Cl2: C, 34.30; H, 9.76; N, 6.96. Found: C, 33.60;
0
ꢂC was monitored by 1H NMR. The solvent was cooled to
about ꢀ25 ꢂC, small amount of dimethyl terephthalate as the
reference was added followed by about 3 mg of the zwitterion. The
spectrometer was thermostated prior to introduction of the NMR
tube. The ratio of the intensity of the most downfield (7.80 ppm, for
1a[NEt4]) or upfield (7.66 ppm, 1b[NEt4]) signals of the aromatic
protons and reference (8.06 ppm) was calculated. A plot of log of
the ratio vrs time (30 min for 1a[NEt4], and 50 min for 1b[NEt4])
gave the decomposition rate.
H, 10.07; N, 6.98.
5.5. Preparation of [closo-B12H11-1-NC5H5]ꢀ [NEt4]þ (3[NEt4])
Dry pyridine (15 mL) was cooled to ꢀ10 ꢂC in an ice-salt bath,
and 4-methoxyphenyliodonium derivative 1b[NEt4] (2.56 g,
5.0 mmol) was added in portions over 15 min. The mixture was
stirred at ꢀ10 ÷ ꢀ5 ꢂC overnight. All volatiles were removed under
reduced pressure (0.1 mm Hg), the oily viscous residue was dis-
solved in MeCN and evaporated with a small portion of SiO2. The
resulting silica gel was loaded onto a SiO2 column, washed with
CH2Cl2 and then the product was eluted with a CH2Cl2/MeOH
mixture (50:3). The crude product was crystallized from MeOH
giving 764 mg (44% yield) of 3[NEt4] as colorless needles: mp
The major organic product of decomposition of [closo-B12H11-1-
IPh]ꢀ [NEt4]þ (1a[NEt4]) was identified as iodobenzene: 1H NMR
(500 MHz, CD3CN)
J2 ¼ 1.1 Hz, 1H), 7.73 (dd, J1 ¼ 8.6 Hz, J2 ¼ 1.1 Hz, 2H). Other signals
include 6.90e7.01 (m), 7.28e7.32 (m), 7.45e7.60 (br m).
d
7.15 (t, J ¼ 7.7 Hz, 2H), 7.38 (tt, J1 ¼ 7.5 Hz,
d
The major organic product of decomposition of [closo-B12H11-1-
(IC6H4OMe-4)]ꢀ [NEt4]þ (1b[NEt4]) was identified as 4-iodoani-
190e192 ꢂC; 1H NMR (500 MHz, CD3CN)
d
0.5e2.0 (br, m, 11H), 1.19
sole: 1H NMR (300 MHz, CD3CN)
d
3.75 (s, 3H), 6.74 (d, J ¼ 8.9 Hz,
(br t, J ¼ 7.2 Hz, 12H), 3.13 (q, J ¼ 7.3 Hz, 8H), 7.63 (t, J ¼ 7.0 Hz, 2H),
2H), 7.59 (d, J ¼ 8.9 Hz, 2H). Other signals include
d 3.72 (s), 6.50 (br
8.15 (t, J ¼ 7.7 Hz, 1H), 9.02 (d, J ¼ 5.8 Hz, 2H); 13C NMR (126 MHz,
d), 6.61 (d), 6.92 (t), 7.16 (br d), 7.44 (br m).
CD3CN)
CD3CN)
d
d
7.7, 53.1 (t, J ¼ 2.3 Hz), 126.8, 143.3, 147.4; 11B (160 MHz,
ꢀ16.6 (d, J ¼ 126 Hz, 1B), ꢀ14.5 (d, J ¼ 130 Hz, 10B), 0.0 (s,
The zwitterion 6 was identified by MS in both samples: HRMS,
calcd for [B12H11C2D3N]ꢀ m/z ¼ 186.2473, found m/z ¼ 186.2489.
j.jorganchem.2015.07.035