Organometallics
Article
nitrosomethylcarbamate is described in the Supporting Information.
Li[N(SO2CF3)2] was purchased from Acros Organics and used
without purification. trans-Ir(Cl)(CO)(PPh3)2,5 trans-Ir(F)(CO)-
(PPh3)2,6 NH4[N(NO2)2],7 K[N(NO2)2],8 Ag[N(NO2)2],9 and
H[N(SO2CF3)2]10 were synthesized according to literature proce-
dures. Ag[N(SO2CF3)2]11 was synthesized from Ag2CO3 instead of
Ag2O. The following reactions were carried out under strict exclusion
of light, due to the light sensitivity of the silver salts.
Silver N-Nitrosomethylcarbamate, Ag[CH3OC(O)NNO] (4).
An isomeric mixture of N-nitrosomethylcarbamate was synthesized
using procedures for N-nitrosoethylcarbamate but with modifications
(Supporting Information).
N-Nitrosomethylcarbamate (0.040 g, 0.385 mmol) was dissolved in
dry CH2Cl2 (4 mL), and Ag2CO3 (0.052 g, 0.189 mmol) was added.
The suspension was stirred overnight to give a yellow suspension. The
solvent of the suspension was removed under vacuum to remove any
unreacted starting nitrosocarbamate, to give yellow solids of
Ag[CH3OC(O)NNO] (4) (0.065 g, 0.308 mmol, 82% yield). Caution!
The yellow solids are sensitive to friction and can detonate! It is best to
resuspend the yellow solids in CH2Cl2 before transferring to a sample
vial followed by removal of the solvent under vacuum. IR (KBr; cm−1):
2958 w, 1697 s, 1441 m, 1211 vs, 1072 s, 960 w, 798 m, 465 w. IR
(Nujol; cm−1): 2723 vw, 1690 m, 1428 m, 1266 s, 1236 s, 1190 m,
1099 m, 955 m, 803 e, 784 m, 722w, 664 vw, 601 vw, 465 m. Anal.
Calcd for C2H3N2O3Ag (210.96 g mol−1): C, 11.39; H, 1.43; N, 13.28.
Found: C, 12.11; H, 1.63; N, 13.17.15 These elemental analyses are a
significant improvement on a prior report and reflect the thermal
instability of these salts.15
Silver N-Nitro-p-tolylsulfonamide, Ag[p-C7H7SO2NNO2] (5).
N-Nitro-p-tolylsulfonamide4b (0.315 g, 1.46 mmol) was dissolved in
CH2Cl2 (5 mL), Ag2CO3 (0.200 g, 0.726 mmol) was added, and the
mixture was stirred overnight at room temperature. The white
suspension was filtered and the residue washed with CH2Cl2 and dried
to give white solids of Ag[p-C7H7SO2NNO2] (5) (0.318 g, 0.986
mmol, 68% yield). IR (KBr; cm−1): 3045 vw, 2920 vw, 1596 w, 1435 s,
1382 m, 1301 vs, 1286 vs, 1151 s, 1140 s, 1078 m, 1044 m, 1018 w,
909 w, 870 w, 815 w, 774 w, 755 w, 666 s, 600 s, 543 m. IR (Nujol;
cm−1): 2725 vw, 2673 vw, 1641w, 1590 vw, 1291 m, 1265 m, 1131 m,
1072 m, 1031 m, 911 m, 813 w, 774 w, 722 w, 666 m, 595 m, 547 w,
492 w. Anal. Calcd for C7H7N2O4SAg (323.08 g mol−1): C, 25.99; H,
2.17; N, 8.67; S, 9.90. Found: C, 26.13; H, 2.11; N, 8.65; S, 10.21.
Ir(η1-CH3C(O)NNO2)(CO)(PPh3)2 (6). trans-Ir(Cl)(CO)(PPh3)2
(0.080 g, 0.103 mmol) was dissolved in degassed CHCl3 (5 mL)
under an N2 atmosphere. Compound 1 (0.022 g, 0.104 mmol) was
added, and the mixture was stirred for 2 h at room temperature. A
white precipitate was formed and was filtered through a Celite plug to
give a yellow solution. The solvent was removed in vacuo, and the
yellow residue was recrystallized from CH2Cl2/CH3OH to give yellow
crystals of Ir(η1-CH3C(O)NNO2)(CO)(PPh3)2 (6) (0.065 g, 0.0767
mmol, 75% yield). IR (KBr; cm−1): 3077 vw, 3053 vw, 1968 vs (CO),
1652 m, 1491 m, 1436 m, 1224 m, 1097 m, 1027 w, 747 m, 694 m,
521 m. Raman (cm−1): 3065 vw, 1970 vw, 1591 m, 1576 vw, 1192 vw,
1100 m, 1030 m, 1002 vs, 618 m, 571 m, 255 w. 1H NMR (200 MHz,
CDCl3) ppm: δ 1.23 (s, 3H), 7.42 (m, PPh3), 7.73 (m, PPh3). 31P{1H}
NMR (81 MHz, CDCl3) ppm: δ 26.76 (s). ESI-MS: 849.16 [M]+.
Decomposition point: 179.3 °C (195.1 kJ mol−1). Anal. Calcd for
C39H33N2O4P2Ir·0.9CH2Cl2 (924.31 g mol−1): C, 51.85; H, 3.79; N,
3.03. Found: C, 52.37; H, 3.22; N, 3.06.
X-ray Crystallography. Crystals were mounted on glass fibers
with epoxy resin or Mitegen mounts using Paratone-N from Hampton
Research, and single-crystal X-ray diffraction experiments were carried
out with a Bruker SMART CCD or Bruker APEX-II CCD
diffractometer by using graphite-monochromated Mo Kα radiation
(λ = 0.71073 Å) and Kryoflex for low-temperature experiments.
SAINT12 was used for integration of the intensity reflections and
scaling and SADABS13 for absorption correction. Direct methods or
Patterson maps were used to generate the initial solutions. Non-
hydrogen atoms were located by difference Fourier maps, and final
solution refinements were solved by full-matrix least-squares methods
on F2 of all data, by using SHELXTL12 software. The hydrogen atoms
were placed in calculated positions. SHELXTL restraints such as
ISOR, SIMU, DELU, and SADI were applied to a disordered solvent
molecule for 9 and for the disordered bistriflimide anion in 13.
Crystals of 6−8 and 10−12 were grown from CH2Cl2/CH3OH
layered solutions at −21 °C, 9 from diffusion of pentanes into
CH2Cl2/THF, and 13 from C2H5OH. Crystallographic data and data
collection parameters for the nitrogen acids and Ir(I) complexes are
shown in Table S1 (Supporting Information).
Silver N-Nitroacetamide, Ag[CH3C(O)NNO2] (1). N-Nitro-
acetamide4a (0.108 g, 1.04 mmol) was dissolved in CH2Cl2 (6 mL),
Ag2CO3 (0.143 g, 0.518 mmol) was added, and the mixture was stirred
overnight at room temperature. The white suspension was filtered,
washed with minimum CH2Cl2, and dried to give white solids of
Ag[CH3C(O)NNO2] (1) (0.210 g, 0.996 mmol, 96% yield). IR (KBr;
cm−1): 1977 vw, 1642 vs, 1504 w, 1427s , 1364 s, 1304 s, 1222 vs,
1048 m, 1037 m, 992 s, 934 m, 797 m, 766 m, 623 m, 477 w. IR
(Nujol; cm−1): 2725 vw, 2669 vw, 1575 m, 1561 m, 1534 m, 1404w,
1312 m, 1235 m, 1208 m, 1105w, 1056w, 1029 m, 887 m, 769 m, 722
m, 632 m, 587 w. Anal. Calcd for C2H3N2O3Ag (210.93 g mol−1): C,
11.37; H, 1.42; N, 13.27. Found: C, 11.47; H, 1.31; N, 12.97.
Silver N-Nitromethylcarbamate, Ag[CH3OC(O)NNO2] (2). N-
Nitromethylcarbamate4a (0.045 g, 0.375 mmol) was dissolved in
CH2Cl2 (5 mL), Ag2CO3 (0.050 g, 0.181 mmol) was added, and the
mixture was stirred overnight at room temperature. The white
suspension was filtered and the residue washed with CH2Cl2 and dried
to give white solids of Ag[CH3OC(O)NNO2] (2) (0.060 g, 0.265
mmol, 73% yield). IR (KBr; cm−1): 3020 vw, 2965w, 1683 vs, 1453 m,
1405 s, 1312 m, 1236 s, 1191 s, 1106 s, 963 w, 806 w, 783 m, 739 w,
430 w. IR (Nujol; cm−1): 2724 vw, 1712 m, 1702 m, 1687 m, 1643 m,
1314 m, 1246 m, 1187 m, 1125 m, 1114 m, 944 m, 797 w, 767 m, 722
m, 664 w, 600 w, 548 vw. IR (Nujol; cm−1): 2723 vw, 2674 vw, 1698
m, 1664 vs, 1421 vs, 1242 vs, 1127s, 1110s, 1023 m, 992 m, 886 m,
821 w, 768 m, 722 w, 455 w. Anal. Calcd for C2H3N2O4Ag (226.93 g
mol−1): C, 10.57; H, 1.32; N, 12.33. Found: C, 10.50; H, 1.28; N,
12.17.
Ir(η1-CH3OC(O)NNO2)(CO)(PPh3)2 (7). trans-Ir(Cl)(CO)(PPh3)2
(0.030 g, 0.0385 mmol) was dissolved in degassed CHCl3 (5 mL)
under an N2 atmosphere. Compound 2 (0.009 g, 0.0397 mmol) was
added, and the mixture was stirred for 3 h at room temperature. A
brown precipitate was formed and was filtered through a Celite plug to
give a yellow solution. The solvent was removed in vacuo, and the
yellow residue was recrystallized from CH2Cl2/CH3OH to give yellow
crystals of Ir(η1-CH3OC(O)NNO2)(CO)(PPh3)2 (7) (0.025 g,
0.0292 mmol, 76% yield). IR (KBr; cm−1): 3055 w, 2921 w, 2851
w, 1965 vs (CO), 1875 w, 1739 s, 1683 w, 1482 m, 1435s, 1315 w,
1230 m, 1204 s, 1181 s, 1160 m, 1096 s, 1027 w, 999 w, 745 m, 694 vs,
611 w, 521 vs, 499 m. 1H NMR (CDCl3) ppm: δ 7.68 (m, PPh3), 7.43
(m, PPh3), 3.08 (s, 3H). 31P{1H} NMR (CDCl3) ppm: δ 25.03 (s).
Decomposition point: 206.4 °C (228.6 kJ mol−1). Anal. Calcd for
C39H33N2O5P2Ir (863.86 g mol−1): C, 54.17; H, 3.82; N, 3.24. Found:
C, 54.19; H, 3.91; N, 3.13.
Silver N-Nitroethylcarbamate, Ag[C2H5OC(O)NNO2] (3). N-
Nitroethylcarbamate4a (0.200 g, 1.49 mmol) was dissolved in CH2Cl2
(5 mL), Ag2CO3 (0.200 g, 0.726 mmol) was added, and the mixture
was stirred overnight at room temperature. The white suspension was
filtered and the residue washed with CH2Cl2 and dried to give white
solids of Ag[C2H5OC(O)NNO2] (3) (0.258 g, 1.07 mmol, 74%
yield). The IR spectroscopic details are identical with those in the
literature.14 IR (KBr; cm−1): 2990 w, 1696 s, 1668 m, 1488 w, 1474 w,
1405 m, 1369 w, 1314 m, 1241 vs, 1127 m, 1097 s, 1033 w, 994 w, 886
w, 769 w, 487 w. IR (Nujol; cm−1): 2723 vw, 2674 vw, 1698 m, 1664 s,
1421s, 1299 m, 1242 vs, 1127 s, 1110 m, 1023 m, 992 m, 886 m, 821
w, 768 m, 722 w, 455 w. Anal. Calcd for C3H5N2O4Ag (240.95 g
mol−1): C, 14.94; H, 2.08; N, 11.62. Found: C, 15.07; H, 1.99; N,
11.60.
Ir(η1-C2H5OC(O)NNO2)(CO)(PPh3)2 (8). trans-Ir(Cl)(CO)(PPh3)2
(0.100 g, 0.128 mmol) was dissolved in degassed CHCl3 (10 mL)
under an N2 atmosphere. Compound 3 (0.037 g, 0.154 mmol) was
added, and the mixture was stirred for 3 h at room temperature. A
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Organometallics 2015, 34, 1074−1084