Transition Met Chem
Anal. Calcd. for C17H14N2O (262.11): C, 77.8; H, 5.3; N,
10.6. Found: C, 77.3; H, 5.4; N, 10.6 %. IR (KBr disk,
cm-1): 1602 (mC=N)s, 1540 m, 1477 m, 1253w, 1160w,
813 m, 743w (mPPh3) cm-1. UV–Vis (CH2Cl2; kmax, nm (e,
UV–Vis (CH2Cl2; kmax, nm (e, M-1 cm-1)): 510 (5510),
415 (8820), 317 (15,310), 270 (23,930).
Synthesis of complex 4
1
M-1 cm-1)): 375 (13,630), 334 (7450), 250 (16,600). H
NMR (CDCl3, 500 MHz): d 12.06 (s, 1H), 8.76 (s, 1H),
7.99 (d, 1H), 7.79–7.73 (m, 3H), 7.51 (d, 1H), 7.49–7.23
(m, 5H), 7.04 (d, 1H), 6.96–6.93 (t, 1H) ppm. 13C NMR
(CDCl3, 500 MHz): d 156.94, 143.52, 137.96, 136.71,
131.30, 131.64, 129.68, 129.21, 128.36, 127.16, 123.38,
120.96, 119.04, 119.98, 112.71 ppm.
Complex 4 was synthesized by the reaction of L4H2
(0.042 g, 0.12 mmol) with [Ru(PPh3)3Cl2] (0.095 g,
0.10 mmol) through the same procedure as for 3. Yield:
0.063 g (62 %). Anal. Calcd. for C53H40ClN4O5P2Ru
(1011.12): C, 62.9; H, 3.9; N, 5.5. Found: C, 62.8; H, 4.0;
N, 5.6 %. IR (KBr disk, cm-1): 1582 (mC=N)s, 1483 m,
1433 m, 1343w, 745 s, 694 s, 522 s (mPPh3) cm-1. UV–Vis
(CH2Cl2; kmax, nm (e, M-1 cm-1)): 560 (6210), 415
(18,010), 327 (18,325), 262 (36,125).
Synthesis of complex 1
Solid [Ru(PPh3)3Cl2] (0.096 g, 0.10 mmol) was added
directly to a hot methanol solution (30 ml) of L1H2
(0.025 g, 0.12 mmol). The reaction mixture was refluxed
for 10–12 h. The resulting yellowish brown crystalline
complex 1, [Ru(L1)(PPh3)2Cl], was collected by filtration
at room temperature after 2–3 days and then washed with
cold methanol and diethyl ether. Yield: 0.057 g (66 %).
Anal. Calcd. for C49H40ClN2OP2Ru (871.13): C, 67.5; H,
4.6; N, 3.2. Found: C, 67.4; H, 4.5; N, 3.1 %. IR (KBr disk,
cm-1): 1605 (mC=N)s, 1428 s, 1297w, 1090 s, 742 m,
695 s, 518 s (mPPh3) cm-1. UV–Vis (CH2Cl2; kmax, nm (e,
M-1 cm-1)): 375 (1050), 295 (8210).
X-ray crystallography
A reddish brown crystal of complex 3 was obtained via
slow evaporation of a solution in dichloromethane/metha-
nol mixture (9:1) which was suitable for diffraction study.
The X-ray data collection and processing was performed
on a Bruker Kappa Apex-II CCD diffractometer using
graphite monochromated Mo–Ka radiation (k = 0.71073
˚
A) at 296 K. The crystal structure was solved by direct
methods. All calculations were performed using the
SHELXTL software package for structure solution and
refinement [25]. All non-hydrogen atoms were refined
anisotropically. Hydrogen atoms were placed in geomet-
rically calculated positions and refined using a riding
model.
Synthesis of complex 2
Complex 2 was prepared by reacting [Ru(PPh3)3Cl2]
(0.096 g, 0.10 mmol) with L2H2 (0.031 g, 0.12 mmol)
following the same procedure described for 1. Complex 2,
formulated as [Ru(L2)(PPh3)2Cl], was yellowish brown in
color. Yield: 0.062 g (67 %). Anal. Calcd. for C53H42-
ClN2OP2Ru (921.15): C, 69.1; H, 4.6; N, 3.0. Found: C,
69.2; H, 4.5; N, 3.1 %. IR (KBr disk, cm-1): 1605 (mC=N)s,
1430 m, 1380 m, 1188w, 1090 m, 742 m, 698 s, 512 s
(mPPh3) cm-1. UV–Vis (CH2Cl2; kmax, nm (e, M-1 cm-1)):
500 (7090), 270 (27,680).
Results and discussion
Synthesis and general properties
The Schiff bases LnH2 (n = 1–4) were prepared in high
yields through the condensation reactions of different
aromatic aldehydes with phenyl hydrazine and 2,4-dini-
trophenyl hydrazine in ethanol using the reported proce-
dures [11] (Figs. S1–S7). Cyclometalated ruthenium(III)
complexes [Ru(L1-4)(PPh3)2Cl] (1–4) (Scheme 3) were
obtained through the addition of solid [Ru(PPh3)3Cl2] to
hot methanolic solutions of the corresponding Schiff bases
L1-4H2. Complexes 1 and 2 were yellowish brown in color,
while 3 and 4 were reddish brown. All four complexes are
highly soluble in dichloromethane, DMF and DMSO but
less soluble in water.
Synthesis of complex 3
A batch of solid L3H2 (0.036 g, 0.12 mmol) was added to a
hot solution of [Ru(PPh3)3Cl2] (0.096 g, 0.10 mmol) in
methanol (30 ml). The reaction mixture was refluxed for
4–5 h and then allowed to cool at room temperature to
obtain a crystalline red-brown solid. This was filtered out
and then washed with cold methanol and diethyl ether to
give complex 3, [Ru(L3)(PPh3)2(Cl)]. Yield: 0.065 g
(68 %). Anal. Calcd. for C49H38ClN4O5P2Ru (961.10): C,
61.2; H, 3.9; N, 5.8. Found: C, 61.1; H, 3.8; N, 5.8 %. IR
(KBr disk, cm-1): 1590 (mC=N)s, 1480 s, 1430 m, 1328 m,
The infrared spectra of complexes 1 and 3 are shown in
Figs. S8 and S9, respectively, and data for all the com-
plexes are deposited in Table S1. All four complexes dis-
played a band in the range 1606–1582 cm-1 assigned to
the azomethine (mC=N) group [10, 11, 23, 24], plus three
1242w, 1175w, 1090 m, 742 s, 698 s, 518 s (mPPh3) cm-1
.
123