L.-H. Tang et al. / Inorganica Chimica Acta 479 (2018) 120–127
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Scheme 1. Synthesis of chiral Schiff bases HL1*, HL2* and HL3*.
recrystallization of two chiral Schiff base ligands in methanol/
diethyl ether (1:3). (Et4N)[RuCl4(MeCN)2] [22], [RuCl3(NO)
(PPh3)2] [23], [RuCl2(PPh3)3] [24], and [Ru(NO)Cl3ÁxH2O] [25] were
prepared according to the literature methods. NMR spectra were
recorded on a Bruker ALX 400 Plus spectrometer operating at
400 MHz for 1H and chemical shifts (d, ppm) were reported with
reference to SiMe4 (1H). Infrared spectra (KBr) were recorded on
a Perkin-Elmer 16 PC FT-IR spectrophotometer with use of pressed
KBr pellets and positive FAB mass spectra were recorded on a Fin-
nigan TSQ 7000 spectrometer. The magnetic moment for the solid
sample was measured by a Sherwood magnetic susceptibility bal-
ance at room temperature. Elemental analyses were carried out
using a Perkin-Elmer 2400 CHN analyzer.
(CDCl3, 400 MHz): d 2.26 (d, 3H, J = 6.8 Hz, CH3), 5.56 (q, 1H, J =
6.0 Hz, C⁄H), 6.63 (t, 2H, J = 5.4 Hz, ArH), 6.75 (t, 2H, J = 5.6 Hz,
ArH), 6.94–7.33 (m, 5H, C⁄Ph), 7.43–7.78 (m, 15H, PPh3), 8.29 (s,
1H, -CH=N) ppm. 31P{1H} NMR (CDCl3, 162 MHz): d 15.2 (s, PPh3)
ppm. MS (FAB): m/z 688 [M+], 653 [M+ À Cl], 618 [M+ À 2Cl], 588
[M+ À 2Cl À NO], 426 [M+ À PPh3], 326 [Ru(
j
2-N,O-L1⁄)]+. Anal.
Calc. for C33H29N2O2PCl2Ru: C, 57.56; H, 4.24; N, 4.07%. Found: C,
57.43; H, 4.22; N, 4.15%.
2.4. Synthesis of (R,R)-[Ru(
j
2-N,O-L2⁄)2Cl(PPh3)] (3)
To a solution of [RuCl2(PPh3)3] (240 mg, 0.25 mmol) in THF
(15 mL) was added a solution of HL2⁄ (130 mg, 0.50 mmol) and
Et3N (56 mg, 0.50 mmol) in THF (5 mL), and then the mixture was
stirred overnight at reflux, during which there was a color change
from brown to dark green. After removal of solvent in vacuo, the
residue was extracted with CH2Cl2 (5 mL Â 2) and the solution
was filtered. The filtrate was layered with Et2O (20 mL) at room
2.2. Synthesis of (R,R)-(Et4N)[Ru(
j
2-N,O-L1⁄)2Cl2] (1)
To a slurry of (Et4N)[RuCl4(MeCN)2] (113.8 mg, 0.25 mmol) in
DMF (5 mL) was added a solution of HL1⁄ (112 mg, 0.50 mmol)
and Et3N (56 mg, 0.50 mmol) in EtOH (5 mL), and then the mixture
was heated at 90 °C with stirring overnight, during which there
was a color change from light red to dark red. Addition of Et2O
(30 mL) to the reaction solution gave brown precipitate which
was filtered and washed with Et2O and hexane. The greenish
brown precipitate was dissolved in CH2Cl2 (10 mL). The clearly
brown filtrate was layered with Et2O (20 mL) at room temperature,
temperature, and dark green block-shaped crystals of [Ru(j
2-N,
O-L2⁄)2Cl(PPh3)] (3) were obtained in three days. Yield: 108 mg,
47% (based on Ru).
leff = 1.97
l
B. IR (KBr disc, cmÀ1): 3024, 2921,
2904 (vCÀH), 1621 (
m
C=N), 1232 (mArÀO), 1445, 1091 and 699 (mPPh3).
MS (FAB): m/z 916 [M+], 881 [M+ À Cl], 654 [M+ À PPh3], 619
[Ru(j
2-N,O-L2⁄)2]+. Anal. Calc. for C48H41N2O2PCl3Ru: C, 62.92; H,
4.51; N, 3.06%. Found: C, 62.67; H, 4.48; N, 3.02%.
and greenish black block-shaped crystals of (Et4N)[Ru(
L1⁄)2Cl2] (1) were isolated in a week. Yield: 115 mg, 61% (based
j
2-N,O-
2.5. Synthesis of (S)-(Et3NH)[Ru(
j
2-N,O-L3⁄)(NO)Cl3] (4)
on Ru).
1623 (
584 [Ru(
leff = 1.99 l
B. IR (KBr disc, cmÀ1): 3034, 2927, 2912 (vCÀH),
m
C=N), 1236 (
m
ArÀO). MS (FAB): m/z 619 [Ru(
j
2-N,O-L1⁄)2Cl2],
To a slurry of Ru(NO)Cl3ÁxH2O (68.4 mg, 0.25 mmol) in DMF (5
mL) was added a solution of HL3⁄ (80 mg, 0.25 mmol) and a little
excess of Et3N (33.0 mg, 0.30 mmol) in THF (10 mL), and then the
reaction mixture was heated at 90 °C with stirring for 4 h, during
which time there was a color change from orange to red. Addition
of Et2O (40 mL) to the reaction solution gave red precipitate which
was filtered and washed with Et2O (5 mL Â 2) and hexane (5 mL).
The red precipitate was dissolved in CH2Cl2 (10 mL). The red
filtrate was layered with THF (5 mL) and Et2O (25 mL) at room
j
2-N,O-L1⁄)2Cl], 549 [Ru(
j
2-N,O-L1⁄)2]. Anal. Calc. for
C38H48N3O2Cl2Ru: C, 60.79; H, 6.44; N, 5.60%. Found: C, 60.71; H,
6.36; N, 5.64%.
2.3. Synthesis of (R)-[Ru(
j
2-N,O-L1⁄)(NO)Cl2(PPh3)] (2)
A mixture of RuCl3(NO)(PPh3)2 (190 mg, 0.25 mmol), HL1⁄ (56
mg, 0.25 mmol) and Et3N (28 mg, 0.25 mmol) in DMF (10 mL) was
heated at 100 °C with stirring overnight, during which there was a
color change from orange to red. Addition of Et2O (30 mL) to the
reaction solution gave red precipitate which was filtered and
washed with Et2O and hexane. The red precipitate was dissolved
in CH2Cl2 (10 mL). The red filtrate was layered with Et2O (10 mL)
and hexane (20 mL) at room temperature, and red pillar-shaped
temperature and red bar-shaped crystals of (Et3NH)[Ru(j
2-N,O-
L3⁄)2(NO)Cl3] (4) were isolated in three days. Yield: 120 mg, 73%.
IR (KBr disc, cmÀ1): 3441 (vNÀH), 3278 (mbr, vOÀH), 3031, 2934,
2912 (vCÀH), 1869 (mN=O), 1626 (mC=N), 1239 (m
ArÀO); 1H NMR (CDCl3,
400 MHz): d 1.01 (s, 9H, CH3), 1.08 (s, 6H, CH(CH3)2), 1.32 (s, 18H,
tBu), 1.95 (sept, 1H, J = 8.2 Hz, CH(CH3)2), 2.56 (t, 6H, J = 3.0 Hz,
CH2), 2.96 (br, 1H, CH2OH), 3.24 (q, 1H, J = 5.6 Hz, C⁄H), 3.89 (m,
2H, CH2OH), 6.82 (t, 1H, J = 4.8 Hz, ArH), 7.09 (d, 1H, J = 4.8 Hz,
crystals of [Ru(
j
2-N,O-L1⁄)(NO)Cl2(PPh3)] (2) suitable for X-ray
diffraction were obtained in five days. Yield: 126 mg, 73% (based
on Ru). IR (KBr disc, cmÀ1): 3031, 2924, 2908 (vCÀH), 1867 (
1629 ( C=N), 1236 ( ArÀO), 1437, 1075 and 691(
PPh3); 1H NMR
m
N=O),
ArH), 8.34 (s, 1H, -CH=N) ppm. MS (FAB): m/z 556 [Ru(
j
2-N,O-
2-N,O-
m
m
m
L3⁄)2(NO)Cl3]+, 521 [Ru(
j
2-N,O-L3⁄)2(NO)Cl2]+, 486 [Ru(
j