Article
Organometallics, Vol. 29, No. 20, 2010 4497
23.01 (CH2CH2CH2); 21.11 (p-CH3); 18.22 (CH3CH2); 17.69
(o-CH3); 14.74 (SiCH2). EM (m/z): 623 (Mþ - Br, 100).
(S)-1-(2,6-Diisopropylphenyl)-3-((6-((2-(methyl(2-(triethoxysilyl)-
propyl)carbamoyl)pyrrolidin-1-yl)methyl)pyridin-2-yl)methyl)-1H-
imidazol-3-ium Bromide ([4b]Br).A mixture of 3-{[6-(bromomethyl)-
pyridin-2-yl]methyl}-1-(2,6-diisopropylphenyl)-1H-imidazol-3-ium15
(1 mmol, 493 mg), potassium carbonate (12 mmol, 1.66 g), and ((S)-
N-methyl-N-(2-(triethoxysilyl)ethyl)pyrrolidine-2-carboxamide
(1 mmol, 332.3 mg) in acetone was stirred at room temperature for
24 h. The crude was washed with diethyl ether to afford the product
as a beige solid (558 mg, 75%). Anal. Calcd for C37H58BrN5O4Si
(744.9): C: 59.7; H: 7.9; N: 10.7. Found: C: 60.5; H: 7.4; N: 10.5.
[R]20D = -18.7 (CH2Cl2, l). IR (KBr, cm-1): ν 2962.8 (m, CH);
salt in CH2Cl2. After stirring overnight at room temperature, the
solution was filtered through Celite. The solvents were removed
in vacuo, and the residue was washed several times with diethyl
ether. Cationic complexes with PF6 as counterion were gener-
ated by halide abstraction via addition of AgPF6 in a CH2Cl2/
H2O solvent system.
[Rh(cod)(3b)]Cl (3bRh): yellow, 94% yield. Anal. Calcd for
C42H63ClN5O4RhSi (868.5): C: 58.1; H: 7.3; N: 8.1; Rh: 11.9.
Found: C: 56.2; H: 7.2; N: 7.8; Rh: 11.1. IR (KBr, cm-1):
ν 2963.8 (m, CH); 1664.5, 1658.0, 1594.1 (CdO, CdC, CdN);
1110.3 (vs, Si-O). UV-vis: λ (nm) 289, 355, 417. 13C NMR
(CD3Cl, ppm): δ 181.28 (C-Rh); 172.53 (CdO); 145.28 (CPy);
135.21 (CPy); 129.87 (Carom); 129.70 (Carom); 128.63 (2Carom);
128.12 (2Carom); 123.16 (Cpy); 122.8 (Cimi); 122.5 (Cimi); 121.52
1
1703.5 (m, CdO); 1655.4 (s, CdC, CdN); 1120.9 (vs, Si-O). H
NMR (CDCl3, ppm): δ 10.16 (1H, s, NCHN); 8.3 (1H, s, Himi); 7.70
(1H, s, Hpy), 7.54-7.51 (1H, m, Hpy); 7.50-7.48 (2H, m, Harom);
7.47 (1H, HPy); 7.28-7.26 (1H, m, Harom); 7.14 (1H, Himi); 6.08
(2H, s, NimiCH2Cpy); 4.10-4.00 (6H, m, CH2CH3); 3.99-3.82
(2H, m, CPyCH2Npro); 3.75-3.60 (3H, m, NCH3); 3.44-3.43
(2H, m, CH2N); 3.42-3.38 (1H, m, CHN); 3.10-3.00 (2H, m, CH2-
CH2Npro); 2.25-2.20 (2H, m, CHiPr); 2.19-2.12 (4H, m, CH2-
CH2CH); 1.78-1.65 (2H, m, CH2CH2CH2); 1.24 (9H, t, CH3); 1.17
(6H, d, CH3); 1.09 (6H, d, CH3); 0.53-0.50 (2H, m, CH2Si). 13C
NMR (CDCl3, ppm): δ 172.25 (CO); 155.25 (Cpy); 147.69 (Cpy);
141.04 (NCHN); 134.04 (Carom); 130.16, (Cpy); 127.72 (2Carom);
126.08 (Carom); 120.49 (Carom); 120.32 (Carom); 123.82 (CHimi);
120.21(CHimi); 118.25 (Cpy); 118.12 (Cpy); 64.52 (NproCH); 58.28
(CpyCH2Npro); 57.86 (CH2CH3); 55.54 (NproCH2CH2); 50.23
(NimiCH2Cpy); 50.05 (CH2N); 32.25 (NCH3); 29.07 (CH(CH3)2);
25.00 (CH(CH3)2); 24.46 (CH2CH2); 24.42 (CH2CH2); 24.16
(CH3CH2); 20.00 (CH2CH2CH2); 10.58 (CH2Si). EM (m/z): 665
(Mþ - Br, 100).
(2Cpy); 100.41 (CdCcod); 78.47 (CdCcod); 67.46 (NproCH2Cpy,
CHN); 64.87 (CH2CH3); 56.80 (NimiCH2CPy, CH2Npro, CH2N);
34.85 (CH2cod); 31.97 (NproCH3); 30.84 (CH2cod); 28.36 (CH2-
CH2CH); 25.93 (CH2CH2CH2); 25.48 (CH3CH2); 18.25 (p-CH3);
17.23 (o-CH3); 14.04 (CH2CH2CH2); 14.03 (CH2CH2CH2);
9.01 (SiCH2). EM (m/z, %): 870 (Mþ þ 1), 605 ([Mþ - CON-
(CH3)(CH2)3Si(OEt)3]).
[Rh(cod)(4c)]Cl (4cRh): yellow, 95% yield. Anal. Calcd for
C50H71ClN5O4RhSi (972.6): C: 61.8; H: 7.4; N: 7.2; Rh: 10.6. Found:
C: 61.4; H: 7.6; N: 7.4; Rh: 10.1. IR (KBr, cm-1): ν 2959 (m,
CH); 1733, 1698 (CdO, CdC, CdN); 1109.9 (vs, Si-O). UV-
vis: λ (nm) 287, 352, 396. 1H NMR (CD3Cl, ppm): δ 7.57-7.40
(11H, m, Harom, HPy); 7.25-7.05 (1H, m, Nim); 6.95-6.85 (2H,
m, Nim); 6.55-6.57 (2H, m, NimCH2Cpy); 4.35-4.32 (2H, m,
CHcod); 4.16-4.12 (2H, m, CpyCH2Npro); 3.50-3.45 (6H, m,
CH2CH3); 3.25-3.10 (5H, m, CH2Npro, NproCH, CH2N);
2.43-2.39 (2H, m, CH2cod); 2.25-2.00 (2H, m, CH2CH2Npro);
2.00-1.78 (8H, m, CH2cod); 1.80-1.75 (6H, m, CHiPr
,
(S)-1-(2,6-Diisopropylphenyl)-3-((6-((2-(phenyl(3-(triethoxysilyl)-
propyl)carbamoyl)pyrrolidin-1-yl)methyl)pyridin-2-yl)methyl)-
1H-imidazol-3-ium Bromide ([4c]Br). A mixture of 3-{[6-(bromo-
methyl)pyridin-2-yl]methyl}-1-(2,6-diisopropylphenyl)-1H-
imidazol-3-ium15 (1 mmol, 493 mg), potassium carbonate (12 mmol,
1.66 g), and ((S)-N-phenyl-N-(2-(triethoxysilyl)propyl)pyrrolidine-
2-carboxamide (synthesized as described in the Supporting Infor-
mation) (1 mmol, 394.6 mg) in acetone was stirred at room
temperature for 24 h. The crude was washed with diethyl ether
to afford the product as a beige solid (565 mg, 70%). Anal. Calcd
for C42H60BrN5O4Si (806.95): C: 62.5; H: 7.5; N: 8.7. Found: C:
63.0; H: 7.2; N: 8.3. [R]20D =-20.0 (CH2Cl2, l). IR (KBr, cm-1):
ν2978.2 (m, CH); 1693.3 (m, CdO); 1654.5 (s, CdC, CdN); 1107.8
(vs, Si-O). 1H NMR (CDCl3, ppm): δ 10.34 (1H, s, NCHN); 7.78
(1H, s, Himi); 7.65 (1H, s, Hpy), 7.53-7.51 (1H, m, Hpy); 7.50-7.45
(3H, m, Harom); 7.35-7.34 (1H, m, HPy); 7.32-7.26 (5H, m,
Harom); 7.0 (1H, s, Himi); 6.23 (2H, s, NimiCH2Cpy); 4.09-3.99
(6H, m, CH2CH3); 3.69-3.58 (2H, m, CPyCH2Npro); 3.53-3.50
(2H, m, CH2N); 3.49-3.44 (1H, m, CHN); 3.15-3.10 (2H, m,
CH2CH2Npro); 2.29-2.25 (2H, m, CHiPr); 2.19-2.12 (4H, m,
CH2CH2CH); 1.70-1.65 (2H, m, CH2CH2CH2); 1.24 (9H, t, CH3);
1.21 (6H, d, CH3); 1.13 (6H, d, CH3); 0.49-0.52 (2H, m, CH2Si).
13C NMR (CDCl3, ppm): δ 145.41 (Cpy); 138.63 (Cpy); 138.36
(NCHN); 138.72, (Carom); 137.09 (Cpy); 132.27 (Carom); 130.26
(Carom);128.5(Carom); 127.3 (Carom); 125.3 (Carom); 124.67 (5 Carom);
124.87 (Carom); 123.82 (CHimi); 123.67 (CHimi); 123.25 (Cpy); 122,1
(Cpy); 64.98 (NproCH); 59.48 (CpyCH2Npro); 57.96 (CH2CH3);
55.54 (NproCH2CH2); 51.82 (NimiCH2Cpy); 50.97 (CH2N); 29.07
(CH(CH3)2); 25.53 (CH(CH3)2); 25.37 (CH2CH2); 24.42 (CH2-
CH2); 24.16 (CH3CH2); 21.19 (CH2CH2CH2); 9.12 (CH2Si). EM
(m/z): 726 (Mþ - Br, 100).
CH2CH2CH, CH2CH2CH2); 1.45 (6H, d, CH3); 1.35 (9H, s,
CH3); 1.17 (6H, d, CH3); 0.78-0.73 (2H, m, CH2Si). 13C NMR
(CD3Cl, ppm): δ 179.61 (C-Rh); 155.68 (CdO); 138.43 (CPy);
136.28 (CPy); 134.95 (Carom); 132.50 (Carom); 131.81 (Carom);
129.57 (Cpy); 129.23 (2Carom); 129.01 (2Carom); 125.75 (2Carom);
124.5 (Carom); 124.0 (2Carom); 123.8 (Cpy); 125.5 (Cimi); 123.35
(Cimi); 122.23 (Cpy); 104.29 (CdCcod); 80.21 (CdCcod); 68.48
(CH2CH3); 68.20 (NproCH2Cpy, CHN); 58.94 (NimiCH2CPy
,
CH2Npro, CH2N); 36.10 (CH2cod); 31.92 (CH(CH3)2); 31.35
(CH2cod); 30.79 (CH(CH3)2); 30.23 (CH2CH2CH); 26.11 (CH2-
CH3); 18.83 (CH2CH2CH2); 14.66 (SiCH2). EM (m/z): 972 (Mþ).
Synthesis of Gold Complexes. The milder conditions of the
transmetalation pathway make it an attractive choice also for
the synthesis of gold(III) complexes. A solution of ligand (2 mmol)
and Ag2O (1 mmol, 231 mg) in dichloromethane was stirred
at room temperature under a N2 atmosphere. The mixture
was filtered through Celite in order to remove unreacted Ag2O
and other insoluble solids. An ethanolic solution of KAuCl4
(1 mmol) was added to the solution of the silver salt in CH2Cl2.
After stirring overnight at room temperature, the solution was
filtered through Celite. The solvents were removed in vacuo, and
the residue was washed several times with diethyl ether.
[AuCl(3b)]Cl2 (3bAu): yellow, 85% yield. Anal. Calcd for
C34H51AuCl3N5O4Si (925.2): C: 44.1; H: 5.7; N: 7.6; Au: 21.3.
Found: C: 43.6; H: 5.3; N: 7.2; Au: 20.8. IR (KBr, cm-1): ν 2975.3
(m, CH); 1686.8 (sh, CdO), 1650.1 (s, CdC, CdN); 1118.1 (vs,
Si-O). UV-vis: λ (nm) 296, 339, 391. 1H NMR (CD3Cl, ppm):
δ 7.93 (1H, s, Himi); 7.35 (2H, Hpy), 7.30-7.28 (1H, m, Harom);
7.25-7.14 (1H, m, Harom); 7.02-7.00 (1H, m, Hpy); 6.92 (1H, d,
H
imi); 5.59-5.51 (2H, m, NimiCH2Cpy); 4.54-4.32(2H, m,
C
PyCH2Npro); 4.03-3.99 (3H, m, CH3N); 3.70-3.68 (6H, m,
Synthesis of Rhodium(I) Complexes. The complexes were
synthesized following the general method: a solution of [4b]Br
(1 mmol, 807.0 mg) and Ag2O (0.5 mmol, 115.5 mg) in dichloro-
methane was stirred at room temperature under a N2 atmo-
sphere. The mixture was filtered through Celite in order to remove
unreacted Ag2O and other insoluble solids. [RhCl(cod)]2 (0.5
mmol, 246 mg) was added to the solution of the resulting silver
CH2CH3); 3.25-3.19 (3H, m, CH2Npro, CHNpro); 3.00-2.95
(2H, m, CH2N); 2.29 (2H, s, p-CH3); 2.11 (6H, s, o-CH3);
1.98-1.75 (4H, m, CH2CH2CH); 1.70-1.60 (2H, m, CH2CH2-
CH2); 1.22 (9H, s, CH3); 0.58-0.56 (2H, m, CH2Si). 13C NMR
(CD3Cl, ppm): δ 190.78 (C-Au); 166.04 (CdO); 145.00 (CPy);
144.32 (CPy); 134.95 (Carom); 134.02 (Cpy); 133.90 (Carom); 129.29
(Carom); 129.57 (Carom); 129.23 (Carom); 129.01 (Carom); 123.50 (Cpy);