N. Thilagavathi et al.
[Ru(CO)(AsPh3)2L4]: 1H NMR (CDCl3, 400 MHz) δ ppm 8.8
(CH N), 6.9–7.5 (aromatic), 3.8 (OCH3).
R
OH
[Ru(CO)(PPh3)(py)L1]: 1H NMR (CDCl3, 400 MHz) δ ppm 8.8
N
HN
O
1
(CH N), 6.9–7.7 (aromatic), 3.8 (OCH3); 31P{ H} NMR (CDCl3,
X
R
1
162 MHz): 22, 29, 41; 13C{ H} NMR (CDCl3, 100 MHz): 140 (CH N),
167 (enolic C), 128–136 (aromatic), 45 (OCH3).
1
[Ru(CO)(PPh3)(py)L2]: 1H NMR (CDCl3, 400 MHz) δ ppm 8.9
1
(CH N), 6.9–7.8 (aromatic), 3.9 (OCH3); 31P{ H} NMR (CDCl3,
Abbreviation
H2L1
R
H
R1
OCH3
OCH3
H
X
162 MHz) 21, 29, 39;
H
H
[Ru(CO)(PPh3)(py)L3]: 1H NMR (CDCl3, 400 MHz) δ ppm 8.9
H2L2
OCH3
H
1
(CH N), 7.1–7.7 (aromatic), 3.79 (OCH3); 31P { H} NMR (CDCl3,
H2L3
Cl
Cl
162 MHz) 22, 29, 39.
[Ru(CO)(PPh3)(py)L4]: 1H NMR (CDCl3, 400 MHz) δ ppm 8.8
H2L4
OCH3
H
1
(CH N), 6.6–7.7 (aromatic), 3.9 (OCH3); 31P{ H} NMR (CDCl3,
1
162 MHz): 21, 29, 39; 13C{ H} NMR (CDCl3, 100 MHz) 145 (CH N),
Scheme 1. Structure of ligands.
165 (enolic C), 127–135 (aromatic), 47 (OCH3).
as KBr pellets in the 4000–400 cm−1 region using a Shimadzu
FT-IR 8000 spectrophotometer. Electronic spectra were recorded
in dichloromethane solution with a Systronics Double beam
Catalytic Oxidation Experiments with Molecular Oxygen
and NMO
Toasolutionofalcohol(0.07–0.13 ml,1 mmol)indichloromethane
(20 ml), was added a solution of the ruthenium complex
(0.009–0.01 g; 0.01 mmol) in dichloromethane (20 ml) and the
mixture was stirred under an oxygen atmosphere at am-
bient temperature for 6 h. The mixture was evaporated to
dryness and extracted with diethyl ether. The combined ex-
tracts were filtered and evaporated to give the corresponding
carbonyl compound, which was then quantified as its 2, 4-
dinitrophenylhydrazone.[21,26]
To a solution of the alcohol (0.07–0.13 ml, 1 mmol) in
dichloromethane(20 ml),NMO(0.35 g,3 mmol)andtheruthenium
complex (0.009–0.01 g, 0.01 mmol) were added and the solution
was heated under reflux for 3 h. The resulting mixture was filtered
and the filtrate was dried over anhydrous Na2SO4. It was then
evaporated to dryness and extracted with diethyl ether. The
diethyl ether extract was filtered and evaporated to give the
corresponding carbonyl compound, which was then quantified as
its 2,4-dinitrophenylhydrazone.[21,27]
1
UV–vis spectrophotometer 2202. H-, 13C- and 31P-NMR spectra
were monitored on a Bruker AMX-400 NMR spectrophotome-
ter using CDCl3 as solvent and tetramethylsilane (1H and 13C)
and orthophosphoric acid (31P) as internal standards at the In-
dian Institute of Science, Bangalore. Cyclic voltammetric studies
were carried out in acetonitrile using a glassy-carbon working
electrode and potentials were referenced to saturated calomel
electrode (SCE). Melting points were recorded with a Raaga
heating table with accuracy 0.1% and are uncorrected. The start-
ing complexes [RuHCl(CO)(PPh3)3],[22] [RuHCl(CO)(AsPh3)3],[23]
[RuHCl(CO)(PPh3)2(py)][24] and the ligands[25] were prepared by
reported methods.
Synthesis of Ruthenium(II) Schiff Base Complexes
To
a
solution of the corresponding starting complex
(0.095–0.108 g; 0.1 mmol) in benzene (25 ml), the appropriate
hydrazone ligand (0.027–0.030 g; 0.1 mmol) in benzene (25 ml)
was added and refluxed for 6 h. The resulting solution was con-
centrated and the product was precipitated by adding a small
quantity of petroleum ether (60–80 ◦C) and dried in vacuo.
NMR data for complex [Ru(CO)(PPh3)2L1]: 1H NMR (CDCl3,
400 MHz) δ ppm 8.9 (CH N), 7.7–7.9 (aromatic), 3.8 (OCH3);
Aryl–Aryl Coupling Experiments
Magnesiumturnings(0.320 g)wereplacedinaflaskequippedwith
a CaCl2 guard tube. A crystal of iodine was added. Bromobenzene
[0.75 ml of total 1.88 ml] in anhydrous diethyl ether (5 ml) was
added with stirring. The remaining bromobenzene in ether (5 ml)
was added dropwise and the mixture was refluxed for 40 min. To
this mixture, 1.03 ml (0.01 mol) of bromobenzene in anhydrous
diethyl ether (5 ml) and the ruthenium complex (0.05 mmol)
chosen for investigation were added and heated under reflux
for 6 h. The reaction mixture was cooled and hydrolyzed with
a saturated solution of aqueous NH4Cl and the ether extract
on evaporation gave a crude product which was purified using
chromatography.[28]
1
31P{ H} NMR (CDCl3, 162 MHz) 21.66.
[Ru(CO)(PPh3)2L2]: 1H NMR(CDCl3, 400 MHz) δ ppm 8.9 (CH N),
1
7.1–7.6 (aromatic), 3.8 (OCH3); 31P{ H}NMR (CDCl3, 162 MHz)
21.79.
[Ru(CO)(PPh3)2L3]: 1H NMR (CDCl3, 400 MHz) δ ppm 8.9 (CH N),
1
7.0–8.0 (aromatic), 3.9 (OCH3); 31P{ H} NMR (CDCl3, 162 MHz)
21.66.
[Ru(CO)(PPh3)2L4]: 1H NMR (CDCl3, 400 MHz) δ ppm 8.8 (CH N),
1
6.8–7.7 (aromatic), 3.9 (OCH3); 31P{ H}NMR (CDCl3, 162 MHz)
1
21.82; 13C{ H}NMR (CDCl3, 100 MHz) 140 (CH N), 165 (enolic
Antibacterial Activity
C), 127–134 (aromatic), 45 (OCH3).
[Ru(CO)(AsPh3)2L1]:1H NMR (CDCl3, 400 MHz) δ ppm 8.9
The bacteria, Escherichia coli and Basillus Subtilis, were cultured in
nutrient agar medium in Petri plates and used as inocula for the
study. The components to be tested were dissolved in DMSO to a
final concentration of 0.5 and 1% and soaked in filter paper disks
of 5 mm diameter and 1 mm thickness. These disks were placed
on the previously seeded plates and incubated at 35 2 ◦C for
24 h. The diameter (mm) of the inhibitory zone around each disk
was measured after 24 h.[29]
1
(CH N), 7.2–7.7 (aromatic), 3.8 (OCH3); 13C{ H} NMR (CDCl3,
100 MHz) 142 (CH N), 167 (enolic C), 127–136 (aromatic), 50
(OCH3).
[Ru(CO)(AsPh3)2L2]: 1H NMR (CDCl3, 400 MHz) δ ppm 8.9
(CH N), 7.1–7.7 (aromatic), 3.8 (OCH3).
[Ru(CO)(AsPh3)2L3]: 1H NMR (CDCl3, 400 MHz) δ ppm 8.9
(CH N), 6.9–7.3 (aromatic), 3.9 (OCH3).
c
Copyright ꢀ 2009 John Wiley & Sons, Ltd.
Appl. Organometal. Chem. 2010, 24, 301–307