Full Paper
Syntheses
(CH), 121.8 (CH tz), 125.4 (C) 128.2 (CH Ar), 129.2 (CH Ar), 129.4 (CH
Ar), 133.8 (C Ar), 136.1 (C), 173.2 (CAu) ppm. HRMS (positive-ions,
CH3CN): calcd. for C14H16N5 (80 %, [L]+) 254.1406, found 254.1387;
calcd. for C16H18N6Au (100 %, [AuL(CH3CN)]+) 491.1259, found
491.1280; calcd. for C16H19AuClNa (10 %, [AuClL(CH3CN)Na]+)
549.0822, found 549.0839 with L = NHC. Crystals of complex 5 were
obtained by slow diffusion of diethyl ether into a solution of the
complex in acetonitrile.
Proligand 1: CH3I (0.09 mL, 1.45 mmol) was added to a solution of
a (0.12 g, 0.47 mmol) in CHCl3 (3 mL). The reaction mixture was
kept at 45 °C whilst stirring for 18 h to give an orange solution.
Addition of diethyl ether (10 mL) afforded the desired product as
an orange solid, which was filtered and dried under vacuum. Yield:
50 % (96 mg). C14H16IN5·1/4H2O·1/4CHCl3 (415.5): calcd. C 41.17, H
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4.06, N 16.85; found C 41.52, H 4.31, N 16.28. H NMR (CDCl3): δ =
4.08 (s, 3 H, CH3), 4.16 (s, 3 H, CH3), 5.63 (s, 2 H, CH2), 7.39 (s, 5 H,
CH Ar), 7.63 (s, 1 H, CH), 8.27 (s, 1 H, CH tz), 9.72 (s, 1 H, CH im)
ppm. 13C{1H} NMR (CDCl3): δ = 36.7 (CH3), 37.3 (CH3), 54.7 (CH2),
121.3 (CH), 124.4 (C), 126.9 (C), 128.5 (CH Ar), 129.2 (CH Ar), 129.3
(CH Ar), 133.7 (CH tz), 137.8 (CH im) ppm; C Ar signal not detected.
ESI-MS (positive-ions, CH3CN): m/z (%) = 254.07 (100) [M – I]+.
Copper(I) Complex 6: A solution of CuI (0.018 g, 0.088 mmol) in
chloroform (5 mL) was added to a solution of the silver(I) complex
4 (0.031 g, 0.077 mmol) in the same solvent (5 mL). The reaction
mixture was left at room temperature whilst stirring for 1 h; after-
wards, it was filtered through Celite, and the filtrate was concen-
trated at low pressure. Addition of diethyl ether (30 mL) afforded
the product as a white solid. The solvent was removed with a syr-
inge, and the solid was dried. Yield: 51 % (14 mg). The copper com-
plex is not stable and tends to decompose both in solution and in
the solid state, as evidenced by the darkening of the solid with time
and by the appearance of a brown/dark precipitate in the NMR
Proligand 2: A solution of a (0.086 g, 0.36 mmol) in CH2Cl2 (6 mL)
was cooled to –78 °C, and then MeOTf (0.12 mL, 1.09 mmol) was
added dropwise. The mixture was warmed to room temperature
and further kept at this temperature whilst stirring for 18 h. The
solvent was removed under vacuum, and the oily residue was
washed with diethyl ether (3 mL) to give an oil. Yield: 39 % (79 mg).
1H NMR ([D6]DMSO): δ = 3.85 (s, 3 H, CH3), 3.97 (s, 3 H, CH3), 4.27
(s, 3 H, CH3), 6.00 (s, 2 H, CH2), 7.50 (m, 5 H, CH Ar), 8.27 (s, 1 H,
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solutions. H NMR (CDCl3): δ = 3.83 (s, 3 H, CH3), 3.97 (s, 3 H, CH3),
5.60 (s, 2 H, CH2), 7.14 (s, 1 H, CH), 7.33 (m, 2 H, CH Ar), 7.43 (m, 3
H, CH Ar), 7.61 (s, 1 H, CH tz) ppm. 13C{1H} NMR (CDCl3): δ = 37.8
(CH3), 38.3 (CH3), 54.0 (CH2), 120.4 (CH), 121.7 (CH tz), 125.7 (C),
128.4 (CH Ar), 128.7 (CH Ar), 129.0 (CH Ar), 133.6 (C Ar), 136.6 (C),
179.8 (CCu) ppm.
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CH), 9.40 (s, 1 H, CH tz), 9.46 (s, 1 H, CH im) ppm. H NMR (CD3CN):
δ = 3.76 (s, 3 H, CH3), 3.93 (s, 3 H, CH3), 4.17 (s, 3 H, CH3), 5.83 (s, 2
H, CH2), 7.51 (m, 5 H, CH Ar), 7.87 (s, 1 H, CH), 8.77 and 8.78 (2s, 2
H, CH tz, CH im) ppm. 13C{1H} NMR ([D6]DMSO): δ = 34.5 (CH3), 36.5
(CH3), 56.6 (CH2), 116.9 (CH), 127.3 (C), 128.9 (CH Ar), 129.0 (CH Ar),
129.2 (CH Ar), 129.3 (C Ar), 131.6 (C), 132.5 (CH tz), 139.8 (CH im)
ppm; CF3 signal not detected, the third CH3 signal is superimposed
with the signal of the deuterated solvent). ESI-MS (positive-ions,
CH3CN): m/z (%) = 135.0 (15) [M – 2 OTf]2+, 178.11 (100) [M – 2 OTf
– C6H5]+, 254.14 (15) [M – 2 OTf – CH3]+, 418.11 (15) [M – OTf]+.
Ruthenium(II) Complex 7: Silver(I) complex
4
(0.027 g,
0.068 mmol) and [RuCl2(p-cymene)]2 (0.023 g, 0.038 mmol) were
placed in a two-neck round-bottomed flask. Subsequently, dry
CH2Cl2 (5 mL) was added, and the reaction mixture was left at 25 °C
whilst stirring for 3 h. Afterwards, it was filtered through Celite, and
the filtrate was concentrated at low pressure; addition of diethyl
ether (15 mL) afforded the product as a brown-orange solid, which
was filtered and dried under vacuum. Yield: 61 % (26 mg).
Silver(I) Complex 4: Proligand 1 (0.11 g, 0.27 mmol) and Ag2O
(0.17 g, 0.72 mmol) were placed in a two-neck round-bottomed
flask. Subsequently, CHCl3 (10 mL) was added, and the reaction
mixture was left at 45 °C whilst stirring for 2 h. Afterwards, it was
filtered through Celite, and the filtrate was concentrated at low
pressure; addition of diethyl ether (20 mL) afforded the product as
a yellow solid that was filtered and dried under vacuum. Yield: 62 %
(67 mg). C14H15AgClN5 (396.63): calcd. C 42.40, H 3.81, N 17.66;
found C 42.22, H 3.85, N 17.36. 1H NMR (CDCl3): δ = 3.82 (s, 3 H,
CH3), 3.95 (s, 3 H, CH3), 5.60 (s, 2 H, CH2), 7.17 (s, 1 H, CH), 7.34 (m,
2 H, CH Ar), 7.40 (m, 3 H, CH Ar), 7.59 (s, 1 H, CH tz) ppm. 13C{1H}
NMR (CDCl3): δ = 38.2 (CH3), 38.9 (CH3), 54.4 (CH2), 120.8 (CH), 122.0
(CH tz), 126.1 (C), 128.2 (CH Ar), 129.1 (CH Ar), 129.3 (CH Ar), 134.0
(C Ar), 136.3 (C), 182.0 (CAg) ppm. ESI-MS (positive-ions, CH3CN):
m/z (%) = 613.13 (100) [AgL2]+ with L = NHC. Crystals of complex
4 were obtained by slow diffusion of diethyl ether into a solution
of the complex in chloroform.
C
24H29Cl2N5Ru·CH2Cl2 (644.4): calcd. C 46.59, H 4.85, N 10.87; found
C 46.02, H 4.67, N 10.78. 1H NMR (CDCl3): δ = 1.27 [m, 6 H, CH(CH3)2],
2.07 (s, 3 H, CH3 p-cym), 2.96 [sept, 1 H, CH(CH3)2], 3.94 and 3.96 (2
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s, 6 H, 2 NCH3), 5.14 (d, JH,H = 6.0 Hz, 2 H, CH Ar p-cymene), 5.42
(d, JH,H = 6.0 Hz, 2 H, CH Ar p-cymene), 5.58 (s, 2 H, CH2), 7.21 (s,
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1 H, CH), 7.30 (m, 5 H, CH Ar), 7.68 (s, 1 H, CH tz) ppm. 13C{1H} NMR
(CDCl3): δ = 18.8 [CH(CH3)2], 22.5 (CH3 p-cym), 31.0 [CH(CH3)2], 38.2
(NCH3), 39.7 (NCH3), 54.5 (CH2), 82.2 (CH p-cym), 85.4 (CH p-cym),
99.0 (C p-cym), 109.5 (C p-cym), 122.8 (CH tz), 123.3 (CH), 126.9 (C),
128.2 (CH Ar), 129.1 (CH Ar), 129.3 (CH Ar), 134.6 (C Ar) 136.7 (C),
175.7 (CRu) ppm. HRMS (positive-ions, CH3CN): calcd. for
C24H29N5ClRu (100 %, [RuCl(L)(p-cym)]+) 524.1153; found 524.1148
with L = NHC.
Attempts To Obtain Silver(I) Complexes by Using Proligand 2:
Proligand 2 (0.069 g, 0.12 mmol) and Ag2O (0.072 g, 0.31 mmol)
were placed in a two-neck round-bottomed flask. Subsequently,
CH3CN (10 mL) was added, and the reaction mixture was left at
Gold(I) Complex 5: A solution of AuCl(SMe2) (0.041 g, 0.14 mmol)
in chloroform (5 mL) was added to a solution of silver(I) complex 4 50 °C whilst stirring for 24 h. Afterwards, it was filtered through
(0.052 g, 0.13 mmol) in the same solvent (10 mL). The reaction
mixture was left at room temperature whilst stirring for 2 h; after-
wards, it was filtered through Celite, and the filtrate was concen-
trated at low pressure. Addition of diethyl ether (30 mL) afforded
Celite, and the filtrate was concentrated at low pressure; addition
of diethyl ether (15 mL) afforded the product as a brown oil. The
solution was removed with a syringe and the oil dried under vac-
uum and analysed without further purification. 1H NMR (CD3CN):
the product as a white solid. The solvent was decanted and re- δ = 3.65 (br. s, 6 H, CH3), 4.09 (s, 3 H, CH3), 5.79 (s, 2 H, CH2), 7.43
moved with a syringe, and the solid was dried under vacuum. Yield:
(m, 5 H, CH Ar), 7.50 (s, 1 H, CH) ppm. 13C{1H} NMR (CD3CN): δ =
51 % (33 mg). C14H15AuClN5·1/4Et2O (504.2): calcd. C 35.70, H 3.50,
N 13.89; found C 35.72, H 3.43, N 14.29. H NMR (CDCl3): δ = 3.82 129.5 (CH Ar), 129.8 (CH Ar), 130.0 (CH Ar), 135.9 (C Ar), 137.5 (C),
38.1 (CH3), 38.3 (CH3), 39.4 (CH3), 59.8 (CH2), 121.8 (CH), 126.5 (C),
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(s, 3 H, CH3), 3.96 (s, 3 H, CH3), 5.61 (s, 2 H, CH2), 7.16 (s, 1 H, CH),
7.35 (m, 2 H, CH Ar), 7.42 (m, 3 H, CH Ar), 7.70 (s, 1 H, CH tz) ppm.
13C{1H} NMR (CDCl3): δ = 37.5 (CH3), 38.4 (CH3), 54.5 (CH2), 120.1
168.6 (CAg tzNHC), 184.5 (CAg nNHC) ppm. MALDI-TOF (dithranol):
m/z (%) = 899.17 (50) [Ag2L2OTf]+, 1049.09 (20) [Ag2L2(OTf)2H]+ with
L = nNHC-tzNHC dicarbene ligand. The same reaction was per-
Eur. J. Inorg. Chem. 2017, 2488–2495
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