J. Chem. Sci.
(2018) 130:163
Page 3 of 8 163
nm ( , dm mol−1cm−1)]: 442 (10527), 320 (31589), 254 H, 5.35; N, 4.96; S, 5.67. 1H NMR δ, ppm (500 MHz,
3
ε
(116862).
DMSO-d6): 1.47 (d, 3H, J
=
5 Hz, CH3), 4.79–4.84
(m, 1H, C*HMe), 5.97 (s, 6H, C6H6), 6.73–8.05 (m, 3H,
aromatic protons), 11.04 (d, 1H, J = 10 Hz, C=S attached
N-H), 11.23 (s, 1H, C=O and C=S attached N-H), 13.20 (bs,
1H, COOH) ppm. 13C NMR δ, ppm (125 MHz, DMSO-d6):
17.1 (CH3), 53.0 (asymmetric carbon), 87.6 (C6H6), 112.5,
118.5, 144.5, 148.3 (aromatic carbons), 157.8 (C=O), 172.8
(C=S), 179.4 (COOH) ppm. FT-IR (KBr, cm−1): 3222 (m;
ν(amide N-H)), 3157 (s; ν(thiourea N-H)), 1681 (s; ν(C=O)),
2.2c [RuCl2(η6-C6 H6)L3](3): Yield: 88 mg, 86%.
◦
27
◦
α
M.p.: 182 C. [ ]D : +71 . Anal. Calcd. for C15H16Cl2N2O3
RuS2: C, 35.44; H, 3.17; N, 5.51; S, 12.61. Found: C, 35.36;
H, 3.06; N, 5.43; S, 12.49. 1H NMR δ, ppm (500 MHz,
DMSO-d6): 1.47 (d, 3H, J
=
5 Hz, CH3), 4.79–4.85
(m, 1H, C*HMe), 5.97 (s, 6H, C6H6), 7.22–8.35 (m, 3H,
aromatic protons), 11.15 (d, 1H, J = 5 Hz, C=S attached N-
H), 11.56 (s, 1H, C=O and C=S attached N-H), 13.20 (bs,
1H, COOH) ppm. 13C NMR δ, ppm (125 MHz, DMSO-d6):
17.1 (CH3), 53.0 (asymmetric carbon), 87.6 (C6H6), 128.6,
132.5, 135.2, 136.5 (aromatic carbons), 162.2 (C=O), 172.8
(C=S), 179.5 (COOH) ppm. FT-IR (KBr, cm−1): 3348 (m;
ν(amide N-H)), 3211 (s; ν(thiourea N-H)), 1697 (s; ν(C=O)),
1740 (s; ν(COOH)), 1196 (s; ν(C=S)). UV-Vis [CHCl3; λ, nm
3
( , dm mol−1cm−1)]: 445 (5354), 324 (29193), 281 (88548),
ε
251 (71193).
2.3 X-ray structure analysis
1725 (s; ν(COOH)), 1191 (s; ν(C=S)). UV-Vis [CHCl3; λ,
The details of data collection are given in Table S1
(Supplementary Information). The crystal was placed in a
cold nitrogen stream maintained at 150 K. A BRUKER
APEX2 X-ray (three-circle) diffractometer was employed
for crystal screening, unit cell determination and data col-
lection.The goniometer was controlled using the APEX2
software suite, v2008-6.0.28 Integrated intensity informa-
tion for each reflection was obtained by the reduction of the
data frames with the program APEX2.28 The absorption cor-
rection program SADABS29 was employed to correct the
data for absorption effects. A solution was obtained read-
ily using XT/XS in APEX2.28,30,31 Hydrogen atoms were
placed in idealized positions and were set riding on the respec-
tive parent atoms. All the non-hydrogen atoms were refined
with anisotropic thermal parameters. The absence of addi-
tional symmetry and voids were confirmed using PLATON
(ADDSYM).32 The structure was refined (weighted least-
squares refinement on F2) to convergence.30,31,33 Olex2 was
employed for the final data presentation and structure plots.33
3
nm ( , dm mol−1cm−1)]: 442 (11483), 330 (70000), 296
ε
(133161), 253 (177806).
2.2d [RuCl2(η6-C6 H6)L4](4): Yield: 90 mg, 88%.
◦
27
M.p.: 183 C. [ ]D : −76◦. Anal. Calcd. for C15H16Cl2N2O3
RuS2: C, 35.44; H, 3.17; N, 5.51; S, 12.61. Found: C, 35.38;
H, 3.07; N, 5.45 S, 12.52. 1H NMR δ, ppm (500 MHz,
α
DMSO-d6): 1.48 (d, 3H, J
=
10 Hz, CH3), 4.80–4.85
(m, 1H, C*HMe), 5.97 (s, 6H, C6H6), 7.23–8.36 (m, 3H,
aromatic protons), 11.15 (d, 1H, J = 5 Hz, C=S attached
N-H), 11.57 (s, 1H, C=O and C=S attached N-H), 13.21 (bs,
1H, COOH) ppm. 13C NMR δ, ppm (125 MHz, DMSO-d6):
17.1 (CH3), 53.0 (asymmetric carbon), 87.6 (C6H6), 128.6,
132.5, 135.2, 136.5 (aromatic carbons), 162.2 (C=O), 172.8
(C=S), 179.5 (COOH) ppm. FT-IR (KBr, cm−1): 3347 (m;
ν(amide N-H)), 3207 (s; ν(thiourea N-H)), 1697 (s; ν(C=O)),
1725 (s; ν(COOH)), 1195 (s; ν(C=S)). UV-Vis [CHCl3;
3
λ, nm ( , dm mol−1cm−1)]: 446 (9196), 330 (65026), 294
ε
(114225), 253 (154844).
2.4 Procedure for ATH of ketones in water
2.2e [RuCl2(η6-C6 H6)L5](5): Yield: 89 mg, 91%.
◦
27
M.p.: 163 C. [ ]D : −48◦. Anal. Calcd. for C19H30Cl2N2O4
RuS: C, 41.16; H, 5.45; N, 5.05; S, 5.78. Found: C, 41.05;
H, 5.34; N, 4.97; S, 5.69. 1H NMR δ, ppm (500 MHz,
DMSO-d6): 1.47 (d, 3H, J = 5 Hz, CH3), 3.39 (bs, COOH,
H2O and COOCH3 merged), 4.80–4.83 (m, 1H, C*HMe),
5.97 (s, 6H, C6H6), 6.73–8.05 (m, 3H, aromatic protons),
α
HCOOH–Et3N (molar ratio 1.0:5.1) mixture was added to
the Ru(II)-benzene complex (0.005 mmol) in water (0.5 mL).
Subsequently ketone (1 mmol) was introduced into the mix-
ture and stirred at 60 ◦C for 15 h. Then, the reaction mixture
was cooled to room temperature, quenched with ice and
extracted with dichloromethane. The extracts were dried over
Na2SO4, filtered, then passed through a silica gel short col-
umn with N-hexane-ethyl acetate (1:1) eluent to remove the
Ru catalyst.
11.04 (d, 1H, J
=
5 Hz, C=S attached N-H), 11.23 (s,
1H, C=O and C=S attached N-H). 13C NMR δ, ppm (125
MHz, DMSO-d6): 17.1 (CH3), 53.0 (asymmetric carbon),
87.6 (C6H6), 112.5, 118.5, 144.5, 148.3 (aromatic carbons),
157.7 (C=O), 172.7 (C=S), 179.4 (COOH) ppm. FT-IR (KBr,
cm−1): 3211 (m; ν(amide N-H)), 3116 (s; ν(thiourea N-H)),
3. Results and Discussion
1665 (s; ν(C=O)), 1701 (s; ν(COOH)), 1201 (s; ν(C=S)). UV-
3
Vis [CHCl3; λ, nm ( , dm mol−1cm−1)]: 449 (7571), 323
ε
3.1 Synthesis of the Ru(II)-benzene complexes
(41360), 284 (114398), 253 (97812).
2.2f [RuCl2(η6-C6 H6)L6](6): Yield: 86 mg, 88%.
The air-stable, water-soluble half-sandwich Ru(II)
◦
27
M.p.: 164 C. [ ]D : +45◦. Anal. Calcd. for C19H30Cl2N2O4
complexes (1–6) were prepared in good yields from the
α
η6
RuS: C, 41.16; H, 5.45; N, 5.05; S, 5.78. Found: C, 41.07; reactions between [RuCl2( -C6H6)]2 and unprotected