F. Caruso et al. / Journal of Inorganic Biochemistry xxx (2016) xxx–xxx
3
round bottom flask (0.5 L) and 10% acetic acid (250 mL) was added. The
reaction mixture was stirred for 5 h at 110 °C. Then the reaction mass
was cooled to room temperature, filtered and transferred into an
round bottom flask (0.5 L); acetone (150 mL) was added and the tem-
perature slowly raised to 65 °C. Afterwards water (150 mL) was added
dropwise and the system refluxed for 2 h. Then the reaction mixture
was cooled to room temperature and filtered. The obtained material
was dried under vacuum for 2 h at 60 °C (13.5 g, 43.8% yield, HPLC pu-
rity: 99%). This is soluble in alcohols, acetone, acetonitrile, DMSO,
chloro-hydrocarbon solvents. M.p.: 157–159 °C. Anal. Calcd. for
149.3, 150.6 (s, C7, C7′, C8, C8′), 178.7 (s, C_O). ESI-MS (+) CH3OH
(m/z, relative intensity %): 575 [100] [(η6-benz)Ru(CurcI)]+.
2.1.2.3. [(η6-hexamethylbenzene)Ru(CurcI)Cl] = [(η6-hmb)Ru(CurcI)Cl]
(3). It was prepared using a procedure similar to that reported for 1
by using [Ru(η6-hmb)Cl2]2. 3 is soluble in alcohols, acetone, acetonitrile,
DMSO and chloro-hydrocarbon solvents. Anal. Calcd. for C35H41ClO6Ru:
C, 60.55; H, 5.95. Found: C, 59.76; H, 5.89; C, 60.23; H, 6.04. Λm
((CH3)2SO, 298 K, 10−3 mol L−1): 5 S cm−2 mol−1. IR (cm−1): 1500s
ν(C_O), 1620m, 1598m, 1580m ν(C_C), 1139s ν(C\\O). 1H NMR
(CDCl3, 298 K): δ 2.13 (s, 18H, C6(CH3)6), 3.92 (s, 12H, CH3O), 5.42 (s,
1H, H\\C1), 6.48 (d, 2H, 3J = 16 Hz, H\\C3, H\\C3′), 6.85 (d, 2H, 3J =
8 Hz, H\\C9, H\\C9′), 7.04 (s, 2H, H\\C6, H\\C6′), 7.09 (d, 2H, 3J =
C21H20O4: C, 74.98: H, 5.99. Found: C, 74.22; H, 5.91; C, 74.69; H, 6.02.
IR (cm−1): 1509m ν(C_O), 1623m, 1601m, 1573m ν(C_C), 1176m
ν(C\\O). 1H NMR (CDCl3, 298 K): δ 3.85 (s, 6H, CH3O), 5.78 (s, 1H,
H\\C1), 6.50 (d, 2H, 3J = 16 Hz, H\\C3, H\\C3′), 6.91 (d, 4H, 3J =
8 Hz, H\\C7′, H\\C9, H\\C9′), 7.51 (d, 4H, 3J = 8 Hz, H\\C6, H\\C6′,
H\\C10, H\\C10′), 7.62 (d, 2H, 3J = 16 Hz, H\\C4, H\\C4′), 16.00 (s,
1H, OH). 13C {1H} NMR (CDCl3, 298 K): δ 55.6 (s, CH3O), 101.6 (s, C1),
114.6 (s, C, C7′, C9, C9′), 122.0 (s, C3, C3′), 128.0 (s, C5, C5′), 130.0 (s,
C6, C6′, C10, C10′), 140.3 (s, C4, C4′), 161.5 (s, C8, C8′), 183.6 (s, C_O).
8 Hz, H\\C10, H\\C10′), 7.57 (d, 2H, 3J = 16 Hz, H\\C4, H\\C4′). 13
C
{1H} NMR (CDCl3, 298 K): δ 15.4 (s, C6(CH3)6), 56.2 (s, CH3O), 90.5 (s,
C6(CH3)6), 102.2 (C1), 109.8s (s, C6, C6′), 111.4 (s, C9, C9′), 122.0 (s,
C10, C10′), 126.7 (s, C3, C3′), 129.3 (s, C5, C5′), 137.8 (s, C4, C4′),
149.4, 150.4 (s, C7, C7′, C8, C8′), 178.1 (s, C_O). ESI-MS (+) CH3OH
(m/z, relative intensity %): 659 [100] [(η6-hmb)Ru(CurcI)]+.
2.1.2.4. [(η6-p-cymene)Ru(CurcII)Cl] (4). Compound 4 was prepared fol-
lowing a procedure similar to that reported for 1 by using [Ru(η6-p-
cymene)Cl2]2 and HCurcII. 4 is soluble in alcohols, acetone, acetonitrile,
DMSO and chloro-hydrocarbon solvents. Anal. Calcd. for C31H33ClO4Ru:
C, 61.43; H, 5.49. Found: C, 61.23; H, 5.36. Λm ((CH3)2SO, 298 K,
10−3 mol L−1): 4 S cm−2 mol−1. IR (cm−1): 1502s ν(C_O), 1624m,
1601m, 1573m ν(C_C), 1168m ν(C\\O). 1H NMR (CDCl3, 298 K): δ
1.39 (d, 6H, 3J = 7.2 Hz, CH3\\C6H4\\CH(CH3)2), 2.28 (s, 3H,
2.1.2. Synthesis of ruthenium complexes
2.1.2.1. [(η6-p-cymene)Ru(CurcI)Cl] (1). The ligand HCurcI (0.1998 g,
0.504 mmol) was dissolved in methanol (20 mL) and KOH (0.0282 g,
0.504 mmol) was added. The mixture was stirred for 1 h at room tem-
perature, and then [Ru(η6-p-cymene)Cl2]2 (0.1543 g, 0.252 mmol)
was added. The resulting solution was refluxed and stirred 24 h. The sol-
vent was removed under reduced pressure, and dichloromethane
(10 mL) was added. The mixture was filtered to remove potassium chlo-
ride. The solution was concentrated to ca. 2 mL and stored at 4 °C. The
red crystals obtained and collected (0.3150 g, 0.473 mmol, yield: 93%)
were soluble in diethyl ether, alcohols, acetone, acetonitrile, DMSO,
and chloro-hydrocarbon solvents. Anal. Calcd. for C33H37ClO6Ru: C,
59.50; H, 5.60. Found: C, 59.10; H, 5.82. Λm ((CH3)2SO, 298 K,
10−3 mol L−1): 3 S cm−2 mol−1. IR (cm−1): 1620m, 1598m, 1579m,
1500s ν(C_C, C_O). 1H NMR (CDCl3, 298 K): δ 1.39 (d, 6H, 3J =
6.8 Hz, CH3\\C6H4\\CH(CH3)2), 2.35 (s, 3H, CH3\\C6H4\\CH(CH3)2),
3.00 (m, 1H, CH3\\C6H4\\CH(CH3)2), 3.91 (s, 12H, CH3O), 5.29 and
5.56 (4H, AA′BB′ system, CH3\\C6H4\\CH(CH3)2 of p-cym, 3J = 6 Hz),
5.48 (s, 1H, H\\C1), 6.44 (d, 2H, 3J = 16.0 Hz, H\\C3, H\\C3′), 6.85 (d,
2H, 3J = 8.0 Hz, H\\C9, H\\C9′) 7.07 (s, 2H, H\\C6, H\\C6′), 7.10 (d,
2H, 3J = 8.0 Hz, H\\C10, H\\C10′), 7.53 (d, 2H, 3J = 16.0 Hz, H\\C4,
H\\C4′). 13C NMR (CDCl3, 298 K): δ 18.3 (s, CH3\\C6H4\\CH(CH3)2),
22.6 (s, CH3\\C6H4\\CH(CH3)2), 31.0 (s, CH3\\C6H4\\CH(CH3)2), 56.1
(s, CH3O), 79.2, 83.2, 97.8, 99.7 (s, CH3\\C6H4\\CH(CH3)2), 102.1 (s,
C1), 109.7 (s, C6, C6′), 111.3 (s, C9, C9′), 122.2 (s, C10, C10′), 125.9 (s,
C3, C3′), 129.1 (s, C5, C5′), 138.7 (s, C4, C4′), 149.3, 150.5 (s, C7, C7′,
C8, C8′), 178.6 (s, C_O). ESI-MS (+) CH3OH (m/z, relative intensity
%): 631 [100] [(η6-cym)Ru(CurcI)]+. This compound has been reported
[39] and its chemical characterization is consistent with our study. See
also X-ray analysis below.
CH3\\C6H4\\CH(CH3)2), 2.98 (sep, 1H, 3J
=
6.8 Hz,
CH3\\C6H4\\CH(CH3)2), 3.83 (s, 6H, CH3O), 5.43 (s, 1H, H\\C1), 5.28,
5.55 (d, 4H, 3J = 6 Hz, CH3\\C6H4\\CH(CH3)2), 6.45 (d, 2H, 3J =
16 Hz, H\\C3, H\\C3′), 6.88 (d, 4H, 3J = 8 Hz, H\\C7, H\\C7′, H\\C9,
H\\C9′), 7.46 (d, 4H, 3J = 8 Hz, H\\C6, H\\C6′, H\\C10, H\\C10′),
7.56 (d, 2H, 3J = 16 Hz, H\\C4, H\\C4′). 13C {1H} NMR (CDCl3, 298 K):
δ 18.2 (s, CH3\\C6H4\\CH(CH3)2), 22.6 (s, CH3\\C6H4\\CH(CH3)2),
31.1 (s, CH3\\C6H4\\CH(CH3)2), 55.5 (s, CH3O), 79.3, 83.2, 97.7, 99.7
(s, CH3\\C6H4\\CH(CH3)2), 102.2 (s, C1), 114.4 (s, C7, C7′, C9, C9′),
125.7 (s, C3, C3′), 128.9 (s, C5, C5′), 129.5 (s, C6, C6′, C10, C10′), 138.5
(s, C4, C4′), 160.8 (s, C8, C8′), 178.6 (s, C_O). ESI-MS (+) CH3OH (m/
z, relative intensity %): 571 [100] [(η6-cym)Ru(CurcII)]+.
2.1.2.5. [(η6-benzene)Ru(CurcII)Cl] (5). Compound 5 was prepared fol-
lowing a procedure similar to that reported for 1 by using [Ru(η6-
benzene)Cl2]2 and HCurcII. 5 is soluble in alcohols, acetone, acetonitrile,
DMSO and chloro-hydrocarbon solvents. Anal. Calcd. for C27H25ClO4Ru:
C, 58.96; H, 4.58. Found: C, 58.84; H, 4.52. Λm ((CH3)2SO, 298 K,
10−3 mol L−1): 5 S cm−2 mol−1. IR (cm−1): 1502m ν(C_O), 1622m,
1600m, 1572m ν(C_C), 1167s ν(C\\O). 1H NMR (CDCl3, 298 K): δ
3.79 (s, 6H, CH3O), 5.43 (s, 1H, H\\C1), 5.68 (s, 6H, C6H6), 6,42 (d, 2H,
3J = 16 Hz, H\\C3, H\\C3′), 6.85 (d, 4H, 3J = 8 Hz, H\\C7, H\\C7′,
H\\C9, H\\C9′), 7.44 (d, 4H, 3J = 8 Hz, H\\C6, H\\C6′, H\\C10,
H\\C10′), 7.56 (d, 2H, 3J = 16 Hz, H\\C4, H\\C4′). 13C {1H} NMR
(CDCl3, 298 K): δ 55.6 (s, CH3O), 82.7 (s, C6H6), 102.1 (s, C1), 114.5 (s,
C7, C7′, C9, C9′), 125.2 (s, C3, C3′), 128.7 (s, C5, C5′), 129.6 (s, C6, C6′,
C10, C10′), 139.1 (s, C4, C4′), 160.9 (s, C8, C8′), 178.7 (s, C_O). ESI-
MS (+) CH3OH (m/z, relative intensity %): 515 [100] [(η6-
benz)Ru(CurcII)]+.
2.1.2.2. [(η6-benzene)Ru(CurcI)Cl] (2). Compound 2 was prepared fol-
lowing a procedure similar to that reported for 1 by using [Ru(η6-
benzene)Cl2]2. 2 is soluble in alcohols, acetone, acetonitrile, DMSO and
chloro-hydrocarbon solvents. Anal. Calcd. for C29H29ClO6Ru: C, 57.09;
H, 4.79. Found: C, 56.89; H, 4.82. Λm ((CH3)2SO, 298 K, 10−3 mol L−1):
4 S cm−2 mol−1. IR (cm−1): 1619m, 1598m, 1580m, 1501s ν(C_C,
C_O). 1H NMR (CDCl3, 298 K): δ 3.91 (s, 12H, \\OCH3), 5.52 (s, 1H,
H\\C1), 5.72, (s, 6H, H-benz), 6.47 (d, 2H, 3J = 16 Hz, H\\C3, H\\C3′),
6.88 (d, 2H, 3J = 8 Hz, H\\C9, H\\C9′) 7.08 (s, 2H, H\\C6, H\\C6′),
7.10 (d, 2H, 3J = 8 Hz, H\\C10, H\\C10′), 7.58 (d, 2H, 3J = 16 Hz,
H\\C4, H\\C4′). 13C {1H} NMR (CDCl3, 298 K): δ 56.1 (s, CH3O), 82.7
(s, C6H6), 101.9 (s, C1), 109.9 (s, C6, C6′), 111.3 (s, C9, C9′), 122.1 (s,
C10, C10′), 125.5 (s, C3, C3′), 129.0 (s, C5, C5′), 139.3 (s, C4, C4′),
2.1.2.6. [(η6-hmb)Ru(CurcII)Cl] (6). Compound 6 was prepared following
a procedure similar to that reported for 1 by using [Ru(η6-hmb)Cl2]2
and HCurcII. 6 is soluble in alcohols, acetone, acetonitrile, DMSO and
chloro-hydrocarbon solvents. Anal. Calcd. for C33H37ClO4Ru: C, 62.50;
H, 5.88. Found: C, 62.29; H, 5.71. Λm ((CH3)2SO, 298 K, 10−3 mol L−1):
5 S cm−2 mol−1. IR (cm−1): 1502m ν(C_O), 1625m, 1601m, 1575m,
1532m ν(C_C), 1159s ν(C\\O). 1H NMR (CDCl3, 298 K): δ 2.12 (s,
18H, C6(CH3)6), 3.83 (s, 6H, CH3O), 5.37 (s, 1H, H\\C1), 6.48 (d, 2H,
Please cite this article as: F. Caruso, et al., The in vitro antitumor activity of arene-ruthenium(II) curcuminoid complexes improves when