INORGANIC AND NANO-METAL CHEMISTRY
463
Scheme 1. Methods prescribed to prepare Ag(I)-NHCs.
the completion of the process DMF was removed. Diethyl General procedure for the preparation of Ag(I)-NHC
ether was added, vigorously shaken, and then decantated. complexes
The white solid was recrystallized from ethanol/diethyl
ether.
A suspension of imidazolium salt (2a–c) and equivalent
amount Ag2O (1.0 mmol) in dichloromethane (15 mL) was
stirred at room temperature for 10 h in the dark conditions and
under argon[12,13] and filtered through celite. The solvent
removed under vacuum. The crude product was recrystallized
from dichloromethane/n-hexane.
1-(methyl)-3-(2,4,6-trimethylbenzyl)imidazolium chloride, 2a
Yield: 76%, m.p.: 120ꢀC. Anal. Calcd. for C14H19N2Cl: C, 67.05;
H, 7.64; N, 11.17. Found: C, 67.26; H, 7.72; N: 11.28. n(CN)
1
D 1634 cm¡1. HNMR (d, DMSO): 2.28 [s, 6H, C6H2(CH3)3];
Chloro-[1-(methyl)-3-(2,4,6-trimethylbenzyl)imidazol-2-
yliden]silver(I), 3a
2.40 [s, 3H, C6H2(CH3)3]; 3.95 [s, 3H, NCH3]; 5.56 [s, 2H,
NCH2C6H2(CH3)3]; 6.92 [d, 1H, J D 1.6 Hz, NCHCHNCH3];
7.04[s, 2H, C6H2(CH3)3]; 7.48 [d, 1H, J D 1.6 Hz, NCHC
HNCH3]; 9.14 [s, 1H, NCHN]. 13C NMR (d, DMSO): 20,0 [C6
H2(CH3)3]; 21.4 [C6H2(CH3)3]; 37.0 [NCH3]; 48.2 [NCH2
C6H2(CH3)3]; 121.0 [NCHCHNCH3]; 124.8 [NCHCHNCH3];
125.7, 130.1, 137.3, 138.1 [C6H2(CH3)3]; 139.8 [NCHN].
Yield: 63%; m.p.: 167ꢀC. Anal. Calcd. for C28H36N4Cl2Ag2: C,
47.02; H, 5.07; N, 7.83. Found: C, 47.46; H, 5.59; N: 7.92. n(CN)
D 1636 cm¡1. 1H NMR (d, CDCl3): 2.26 [s, 12H, C6H2(CH3)3];
2.31 [s, 6H, C6H2(CH3)3]; 3.86 [s, 6H, NCH3]; 5.28 [s, 4H,
NCH2C6H2(CH3)3]; 6.57 [d, 2H, J D 4.0 Hz, NCHCHNCH3];
6.90 [d, 2H, J D 4.0 Hz, NCHCHNCH3]; 7.01 [s, 4H,
C6H2(CH3)3]. 13C NMR (d, CDCl3): 20.4 [C6H2(CH3)3]; 21.3
[C6H2(CH3)3]; 39.2 [NCH3]; 49.6 [NCH2C6H2(CH3)3]; 120.1
[NCHCHNCH3]; 122.0 [NCHCHNCH3]; 127.8, 129.9, 138.1,
139.2 [Ar–C]; 182.6 [Ag–Ccarbene].
1-(methyl)-3-(2,3,5,6-tetramethylbenzyl)imidazolium
chloride, 2b
Yield: 64%, m.p.: 127ꢀC. Anal. Calcd. for C15H21N2Cl: C, 68.04; H,
7.99; N, 10.58. Found: C, 68.16; H, 8.12; N: 10.67. n(CN)
D
1636 cm¡1. HNMR H NMR (d, DMSO): 2.23 [s, 6H, C6H
(CH3)4]; 2.29 [s, 6H, C6H(CH3)4]; 3.94 [s, 3H, NCH3]; 5.59 [s, 2H,
NCH2C6H(CH3)4]; 6.86 [d, 1H, J D 1.6 Hz, NCHCHN]; 7.02
[s, 1H, C6H(CH3)4]; 7.74 [d, 1H, J D 1.6 Hz, NCHCHN]; 9.12 [s,
1H, NCHN]. 13C NMR (d, DMSO): 16.0 [C6H(CH3)4]; 20.8 [C6H
(CH3)4]; 37.1 [NCH3]; 48.9 [NCH2C6H(CH3)4]; 121.3
[NCHCHNCH3]; 123.2 [NCHCHNCH3]; 128.2, 134.1, 134.4,
135.2 [C6H(CH3)4]; 136.4 [NCHN].
1
1
Chloro-[1-(methyl)-3-(2,3,5,6-tetramethylbenzyl)imidazol-2-
yliden]silver(I), 3b
Yield: %55; m.p.: 156ꢀC. Anal. Calcd. for C30H40N4Cl2Ag2: C,
48.48; H, 5.42; N, 7.54. Found: C, 48.82; H, 5.61; N: 7.75. n(CN)
D 1634 cm¡1. 1H NMR (d, CDCl3): 2.16 [s, 12H, C6H(CH3)4];
2.25 [s, 12H, C6H(CH3)4]; 3.91 [s, 6H, NCH3]; 5.44 [s, 4H,
NCH2C6H(CH3)4]; 6.55 [d, 2H, J D 4.0 Hz, NCHCHNCH3];
6.97 [d, 2H, J D 4.0 Hz, NCHCHNCH3]; 7.06 [s, 2H, C6H
(CH3)4]. 13C NMR (d, CDCl3): 16.2 [C6H(CH3)4]; 20.6 [C6H
(CH3)4]; 39.3 [NCH3]; 50.5 [NCH2C6H(CH3)4]; 120.8
[NCHCHNCH3]; 121.9 [NCHCHNCH3]; 130.4, 132.9, 134.1,
134.7 [Ar–C]; 182.8 [Ag–Ccarbene].
1-(methyl)-3-(pentamethylbenzyl)imidazolium chloride, 2c
Yield: 65%, m.p.: 195ꢀC. Anal. Calcd. for C16H23N2Cl: C, 68.92;
H, 8.31; N, 10.05. Found: C, 68.91; H, 8.24; N: 10.21. n(CN)
D
1
1636 cm¡1. H NMR (d, DMSO): 2.24 [s,6H, C6(CH3)5]; 2.25 Chloro-[1-(methyl)-3-(pentamethylbenzyl)imidazol-2-yliden]
[s, 6H, C6(CH3)5]; 2.27 [s, 3H, C6(CH3)5]; 3.92 [s,3H, NCH3]; silver(I), 3c
5.54 [s, 2H, NCH2C6(CH3)5]; 7.62 [d, 1H, J D 1.6 Hz, Yield: %60; m.p.: 147ꢀC. Anal. Calcd. for C32H44N4Cl2Ag2: C,
NCHCHNCH3]; 7.74 [d, 1H, J D 1.6 Hz, NCHCHNCH3]; 8.96 49.83; H, 5.75; N, 7.26. Found: C, 49.94; H, 5.92; N: 7.74. n(CN)
1
[s, 1H,NCHN]. 13C NMR (d, DMSO): 17.1 [C6(CH3)5]; 17.3 D 1633 cm¡1. H NMR (d, CDCl3): 2.22 [s, 12H, C6(CH3)5];
[C6(CH3)5]; 17.5 [C6(CH3)5]; 37.2 [NCH3]; 49.4 [NCH2C6 2.28 [s, 12H, C6(CH3)5]; 2.30 [s, 6H, C6(CH3)5]; 3.84 [s, 6H,
(CH3)5]; 121.0 [NCHCHNCH3]; 123.6 [NCHCHNCH3]; 125.1, NCH3]; 5.35 [s, 4H, NCH2C6(CH3)5]; 6.63 [d, 2H, J D 4.0 Hz,
133.2, 133.8, 136.4 [C6(CH3)5]; 136.8 [NCHN].
NCHCHNCH3]; 6.90 [d, 2H, J D 4.0 Hz, NCHCHNCH3]. 13C