180
B.G. Bharate et al. / Polyhedron 33 (2012) 179–184
from Aldrich and were used as received. The Schiff base ligands
N-(2-pyridylmethylene)phenylamine (L1), 4-bromo-N-(pyridylm-
ethylene)phenylamine (L2) and 4-nitro-N-(2-pyridylmethyl-
ene)phenylamine (L3) were prepared as previously reported [19].
RuCl2(dmso)4 [20] and cis-RuCl2(dppe)2 [21] were prepared
according to the literature procedures.
stirred at room temperature in CH2Cl2 (25 ml) for 16 h. NEt3
(1 ml) was added and the solution was immediately passed
through a short pad of alumina eluting with CH2Cl2. The solvent
was removed from the eluate under reduced pressure and the
resulting yellow powder was stirred with diethylether to remove
unreacted trans-[RuCl2(dppe)2]. The product was further purified
by column chromatography on alumina using 4:1 CH2Cl2:petro-
leum ether as the eluent to afford a yellow colored solid. Yield:
0.834 g, 78%. Elemental analysis (C, H and N, wt%) Anal. Calc. for
Elemental analysis (C, H and N) were performed on a Thermo
Finnigan FLASH EA-112 CHNS analyzer. Electronic spectra were re-
corded on a Shimadzu UV–Vis-NIR-100 spectrophotometer. Infra-
red spectra were recorded on a Perkin-Elmer FT-IR spectrometer
as KBr pellets in the 4000–400 cmꢀ1 spectral range. 1H NMR spectra
of the samples dissolved in CDCl3 were measured on a Bruker-
300 MHz instrument using TMS [(CH3)4Si] as an internal standard
for the chemical shifts (ppm). 31P NMR spectra were recorded using
a Varian Mercury-300 FT NMR spectrometer. The 1H and 31P NMR
spectra are referenced to residual chloroform (7.26 ppm) and exter-
nal H3PO4 (0.0 ppm), respectively. ESI mass spectra were recorded
using a Bruker Apex3. Thermal analysis of the complexes was car-
ried out on a Perkin-Elmer thermal analyzer in a nitrogen atmo-
sphere at a heating rate of 10 °C/min. Luminescence properties
were measured using a JASCO F.P.750 fluorescence spectrophotom-
eter equipped with quartz cuvette of 1 cm3 path length at room
temperature. Cyclic voltammetry measurements were performed
with a CH-400A Electrochemical Analyzer. A standard three elec-
trode system, consisting of a Pt disk working electrode, Pt wire
counter electrode and Ag/AgCl reference electrode containing aque-
ous 3 M KCl were used. All potentials were converted to the SCE
scale. Tetrabutyl ammonium perchlorate (TBAP) was used as the
supporting electrolyte and all measurements were carried out in
C
59H52NClP4Ru: C, 68.65; H, 5.06; N, 1.35. Found: C, 68.07; H,
4.67; N, 1.78%. IR (cmꢀ1):
m(RuC„C) 2074; UV–Vis (CH2Cl2) kmax
(nm) (
H
e
ꢁ 103, Mꢀ1 cmꢀ1): 331 (5.9); 1H NMR d: 8.23 (s, 1H, Py-
oN,oC„C), 8.05 (d, 1H, Py-HoN,pC„C), 6.67–7.73 (m, 42H, phenyl),
2.69 (m, 8H, PCH2CH2P); 31P NMR d: 49.6; ESI MS: 1058
([NC5H4C„CRuCl(dppe)2+Na]+, 23), 999 ([NC5H4C„CRu(dppe)2]+,
100), 898 ([Ru(dppe)2]+, 58).
2.2.4. Synthesis of trans-[RuCl(dppe)2(C„CC6H4C„C-py-3)] (2)
(4-Ethynylphenyl)(3-pyridyl)acetylene (0.200 g, 0.980 mmol),
cis-[RuCl2(dppe)2] (0.905 g, 0.934 mmol) and NaPF6 (0.047 g,
2.810 mmol) were stirred at room temperature in CH2Cl2 (25 ml)
for 16 h. NEt3 (1 ml) was added and the solution was immediately
passed through a short pad of alumina eluting with CH2Cl2. The sol-
vent was removed from the eluate under reduced pressure and the
resulting yellow powder was stirred with diethylether to remove
unreacted trans-[RuCl2(dppe)2]. The product was further purified
by column chromatography on alumina using 4:1 CH2Cl2:petroleum
ether as the eluent to afford a yellow colored solid. Yield: 0.760 g,
72%. Elemental analysis (C,
H and N, wt%) Anal. Calc. for
CH2Cl2 solution at room temperature with
a scan rate of
C
67H56NClP4Ru: C, 70.86; H, 4.97; N, 1.23. Found: C, 70.18; H, 4.47;
100 mV sꢀ1
.
N, 1.78%. IR (cmꢀ1):
m(RuC„C) 2073; UV–Vis (CH2Cl2) kmax (nm)
(e
ꢁ 103, Mꢀ1 cmꢀ1): 351 (9.8); 1H NMR d: 8.73 (s, 1H, Py-HoN,oC„C),
2.2. Synthesis
8.53 (d, 1H, Py-HoN,pC„C), 6.63–7.78 (m, 46H, phenyl), 2.69 (m, 8H,
PCH2CH2P); 31P NMR d: 49.8; ESI MS: 1158 ([NC5H4C„CC6H4C„
CRuCl(dppe)2+Na]+, 28), 1101 ([NC5H4C„CC6H4C„CRu(dppe)2]+,
100), 898 ([Ru(dppe)2]+, 41).
2.2.1. Synthesis of [4-(trimethylsilyl)ethynyl](3-pyridyl)acetylene
A flask was charged with 3-ethynylpyridine (0.300 g, 2.9 mmol),
(CH3)3SiC„CC6H4I (0.873 g, 2.9 mmol), PdCl2(PPh3)2 (0.061 g,
0.086 mmol) and CuI (0.022 g, 0.116 mmol), and then 30 ml of
Et2NH was added to it. The mixture was stirred at room tempera-
ture for 17 h. The solvent was removed under vacuum and the
remaining yellow residue was extracted with CH2Cl2/H2O. The
organic layer was collected, dried and passed through a neutral
alumina column using 1:3 CH2Cl2:petroleum ether as the eluent.
The removal of the solvent under vacuum yielded a pale yellow
colored product. Yield: 0.700 g, 82%; 1H NMR d: 8.77 (s, 1H, Py-
2.2.5. Synthesis of [Cu(L1)(NC5H4C„CRu(dppe)2Cl)I] (3)
To
a solution of trans-[RuCl(dppe)2(C„C-py-3)] (0.250 g
0.240 mmol) in CH2Cl2 (10 ml), the Schiff base ligand L1 in 5 ml
methanol (0.044 g, 0.24 mmol) and CuI (0.046 g, 0.24 mmol) were
added. The reaction mixture was stirred for 2 h at room tempera-
ture and then the solution was evaporated to a small volume under
vacuum. The reddish brown colored complex was developed by
diffusion of diethyl ether into the solution. Yield: 0.258 g, 76%.
Elemental analysis (C, H and N, wt%) Anal. Calc. for C71H62N3ClIP4-
CuRu: C, 60.56; H, 4.44; N, 2.98. Found: C, 60.15; H, 4.18; N, 3.08%;
HoN,oC„C), 8.56 (d, 1H, Py-HoN,pC„C), 7.84 (d, 1H, Py-HpN,oC„C),
7.50 (m, 4H, C6H4), 7.32 (t, 1H, Py-HmN,mC„C), 0.26 (s, 9H, Me);
MS(EI): m/e 275 (M+).
IR (KBr) (cmꢀ1): 2065
693 (dppe); UV–Vis (CH2Cl2) kmax (nm) (
m(C„C); 1585 m(HC@N); 1483, 1435, 1165,
m
e
ꢁ 103, Mꢀ1 cmꢀ1): 348
2.2.2. Synthesis of (4-ethynylphenyl)(3-pyridyl)acetylene
(16.7); 1H NMR d: 9.10 (s, HC@N), 8.25 (s, 1H, Py-HoN,oC„C), 8.03
(d, 1H, Py-HoN,pC„C), 6.91–8.01 (m, 51H, phenyl), 2.68 (s, 8H,
PCH2CH2P); 31P NMR d: 49.5; ESI MS: 1431 ([Cu(L1)NC5H4C„-
CRu(dppe)2Cl+Na]+, 24), 1225 ([Cu(NC5H4C„CRu(dppe)2Cl)I]+,
100), 898 ([Ru(dppe)2]+, 41).
Powdered KOH (0.264 g, 4.27 mmol) was added to a solu-
tion of [4-(trimethylsilyl)ethynyl](3-pyridyl)acetylene (0.650 g,
2.36 mmol) in 40 ml of MeOH, and the resulting solution was stir-
red at room temperature for 2 h. The solvent was removed under
vacuum, and the residue was extracted with CH2Cl2/H2O. The
organic layer was collected, dried and passed through a neutral
alumina column using 1:3 CH2Cl2:petroleum ether as the eluent.
The removal of the solvent under vacuum yielded a white colored
product. Yield: 0.393 g, 82%; 1H NMR d: 8.74 (s, 1H, Py-HoN,oC„C),
8.58 (d, 1H, Py-HoN,pC„C), 7.81 (d, 1H, Py-HpN,oC„C), 7.49 (m, 4H,
C6H4), 7.31 (t, 1H, Py-HmN,mC„C), 3.21 (s, 1H, HC„C); MS(EI): m/e
203 (M+).
2.2.6. Synthesis of [Cu(L2)(NC5H4C„CRu(dppe)2Cl)I] (4)
The complex 4 was prepared similar to the procedure performed
in the preparation of 3 except that L1 was replaced by L2 (0.24 mmol,
0.548 g). Yield: 0.265 g, 74%. Elemental analysis (C, H and N, wt%)
Anal. Calc. for C71H61N3ClBrP4CuRu: C, 57.35; H, 4.13; N, 2.83. Found:
C, 57.08; H, 4.03; N, 3.18%; IR (KBr) (cmꢀ1): 2067
m(C„C); 1587
m
(HC@N); 1482, 1435, 1164, 693 m(dppe); UV–Vis (CH2Cl2) kmax
2.2.3. Synthesis of trans-[RuCl(dppe)2(C„C-py-3)] (1)
3-Ethynylpyridine (0.117 g, 1.136 mmol), cis-[RuCl2(dppe)2]
(1.000 g, 1.033 mmol) and NaPF6 (0.520 g, 3.098 mmol) were
(nm) (
e
ꢁ 103, Mꢀ1 cmꢀ1): 348 (19); 1H NMR d: 9.11 (s, HC@N),
8.35 (s, 1H, Py-HoN,oC„C), 8.04 (d, 1H, Py-HoN,pC„C), 6.82–8.01 (m,
50H, phenyl), 2.67 (s, 8H, PCH2CH2P); 31P NMR d: 49.6; ESI MS: