Batey et al.
with a Metler Toledo InLab 422 pH electrode. The pH scale was
calibrated by using Gran’s method.30 Infrared spectra were recorded
on a Perkin-Elmer Lambda 7 FT-IR instrument. Electrospray
ionization mass spectra were obtained using a Finnigan LCT mass
spectrometer and CI and EI mass spectra were measured on a VG
Analytical Autospec mass spectrometer. HR-mass spectra were
obtained from the EPSRC National Mass Spectrometry Service
Centre in Swansea. Elemental analyses were performed by the
analytical services at the University of Manchester. Diffraction data
were collected on a Bruker Smart Apex diffractometer with an
Oxford cryostream cooling system and Mo KR radiation source
using a SMART CCD camera. Structures were solved by direct
methods using SHELXS-97 and refined by full-matrix least-squares
using SHELXL-97 (G. M. Sheldrick, University of Go¨ttingen,
Germany, 1997). All non-hydrogen atoms were refined anisotro-
pically. Hydrogen atoms were placed using a riding model and
included in the refinement at calculated positions.
(m, 4H, bpy CH), 8.17 (d, 1H, phen CH), 8.11 (m, 2H, bpy CH),
8.01 (m, 3H, bpy CH and phen CH), 7.84 (m, 3H, bpy CH and
phen CH), 7.72 (m, 3H, phen CH and cat CH), 7.58 (m, 2H, bpy
CH), 7.46 (m, 2H, bpy CH), 7.32 (m, 2H, cat CH), 7.26 (m, 2H,
bpy CH), 3.93 (s, 6H, CH3). 13C NMR (125 MHz, CD3CN): δ
165.4 (CdO), 153.9 (CH bpy), 153.6 (CH phen), 153.0 (CH bpy),
152.3 (CH phen), 138.9 (CH bpy), 137.4 (CH phen), 132.1(CH
phen), 128.6 (CH bpy), 128.4 (CH bpy), 127.3 (CH cat), 127.0
(CH phen), 126.0 (CH cat), 125.3 (CH bpy), 123.1 (CH cat), 118.6
(CH phen), 117.9 (CH phen), 62.6 (-OCH3), 56.9 (-OCH3). UV-
vis (CH3CN/H2O 20:1): ꢀ450
)16 500 dm3 mol-1 cm-1
.
nm
Mp: 274-276 °C. HR-ESI-MS: m/z 912.1357 (calculated for
C41H33O3N7F6P96Ru: 912.1358).
Synthesis of [Ru(bpy)2(H2-L3)](PF6)2, 3 (PF6)2. Under an inert
atmosphere, [Ru(bpy)2(Me2-L3)](PF6)2 (0.25 g, 0.24 mmol) was
dissolved in 15 mL anhydrous dichloromethane. The solution was
cooled to -78 °C, and a 10-fold molar excess of 1.0 M boron
tribromide in dichloromethane was added slowly. The reaction was
stirred at -78 °C for 1 h and then allowed to warm to room
temperature over 12 h. Water was added carefully until no more
HBr evolved. The mixture was evaporated to dryness, and the
residue was taken up in methanol, which was evaporated to remove
boron-containing byproducts. The residue was then dissolved in a
minimum amount of methanol, and the solution was brought to
neutral pH with 3 M NaOH to precipitate the product. To ensure
that all 3 precipitated, a few drops of a saturated ammonium
hexafluorophosphate solution were added and the mixture was
cooled to 4 °C for 12 h. The precipitate was isolated, washed with
cold water, and dried in vacuo. Yield: 0.17 g (0.16 mmol, 68%).
1H NMR (500 MHz, CD3CN): δ 8.923 (d, 1H, phen CH), 8.695
(m, 2H, phen CH), 8.534 (m, 5H, bpy CH), 8.160 (m, 2H, phen
CH), 8.107 (m, 2H, bpy CH), 8.014 (m, 4H, bpy CH), 7.841 (m,
3H bpy CH and phen CH), 7.741 (m, 1H, phen CH, 7.31 (d, 1H,
cat CH), 7.584 (d, 1H, cat CH), 7.465 (m, 2H, bpy CH), 7.286 (m,
2H, bpy CH and cat CH). 13C NMR (125 MHz, CD3CN): δ 170.0
(CdO), 154.5 (phen CH), 154.4 (phen CH), 153.2 (cat CH), 153.0
(cat CH), 153.9 (bpy CH), 141.1 (bpy CH), 138.9 (bpy CH), 138.2
(phen CH), 134.8 (phen CH), 131.5 (phen CH), 128.6 (bpy CH),
128.5 (cat CH), 127.9 (phen CH), 127.6 (phen CH), 125.3 (bpy
CH). UV-vis (CH3CN/H2O, 20:1; pH 6): ꢀ450 nm ) 17 100 dm3
mol-1 cm-1. Mp: 279-280 °C. HR-ESI-MS: m/z ) 890.1012
(calculated for C39H29O3N7F6P102Ru: 890.1012).
Synthesis of [ReBr(CO)3(Me2-L3)]. Me2-L3 (0.34 g, 0.94 mmol)
and rhenium pentacarbonyl bromide (0.19 g, 0.46 mmol) were
dissolved in 80 mL dry toluene and refluxed for 4 h under an inert
atmosphere. Once the completeness of the reaction was confirmed
by IR spectroscopy, the volume of the reaction mixture was reduced
to half. A yellow precipitate formed, which was isolated, washed
with cold toluene, and dried. Yield: 0.29 g (0.41 mmol, 90%). 1H
NMR: (500 MHz, CDCl3): δ 11.104 (s, 1H, NH), 9.460 (d, 1H,
phen CH), 9.286 (d, 1H, phen CH), 9.143 (s, 1H, phen CH), 8.666
(d, 1H, phen CH), 8.505 (d, 1H, phen CH), 7.911 (m, 1H, phen
CH), 7.866 (d, 1H, cat CH), 7.816 (m, 1H, phen CH), 7.364 (t,
1H, cat CH), 7.209 (d, 1H, cat CH), 4.101 (s, 3H, CH3), 3.993 (s,
3H, OCH3). 13C NMR (125 MHz, CDCl3): δ 196.6 (Re-CO),
163.9 (CdO), 153.1 (phen CH), 152.0 (phen CH), 137.8 (phen CH),
131.0 (phen CH), 126.2 (phen CH), 125.6 (phen CH), 125.5 (cat
CH), 123.2 (cat CH), 116.9 (cat CH), 116.5 (phen CH), 62.4
Synthesis of 2,3-Dimethoxy-N-(1,10-phenanthroline-5-yl)ben-
zamide, Me2-L3. Dicyclohexylcarbodiimide (1.13 g, 5.5 mmol) was
added at 0 °C to a stirred solution of 2,3-dimethoxybenzoic acid
(2.00 g, 11.0 mmol) in 50 mL of dry acetonitrile. After 15 min,
the reaction was brought to room temperature and stirred until thin-
layer chromatography (TLC) analysis (10:1 chloroform/methanol
v/v) confirmed that the reaction had gone to completion. After
removal of the precipitated byproduct by filtration, the filtrate was
evaporated to dryness. 2,3-Dimethoxybenzoic anhydride was
obtained as an oily residue, which was redissolved in 20 mL
anhydrous acetonitrile. 1,10-Phenanthroline-5-yl amine (0.80 g,
4.1 mmol) was suspended in 50 mL anhydrous chloroform, and
the insoluble components were removed by filtration. The resulting
solution was added to the 2,3-dimethoxybenzoic anhydride solution,
and the mixture was refluxed for 6 h under N2 and under exclusion
of light. After the removal of the solvents, the residual oil was
taken up in chloroform. The product was extracted from the organic
phase with 2 M HCl. The pH of the aqueous phase was then
increased to 10 with 3 M NaOH, and the product was re-extracted
into chloroform. The solvent was removed in vacuo, and the
remaining white solid was vacuum-dried. Recrystallization from
chloroform/petroleum ether gave the pure product. Yield: 1.23 g
(3.4 mmol, 83%). 1H NMR (500 MHz, CD3CN): δ 10.511 (s, 1H,
NH), 9.155 (d, 1H, phen CH), 9.042 (d, 1H, phen CH), 8.605 (s,
1H, phen CH), 8.515 (d, 1H, phen CH), 8.356 (d, 1H, phen CH),
7.804 (m, 1H, phen CH), 7.679 (m, 2H, 1 phen CH, 1 cat CH),
7.274 (m, 2H, cat CH), 4.089 (s, 3H, CH3), 3.953 (s, 3H, CH3).
13C NMR (125 MHz, CD3CN): δ 165.2 (CdO), 150.9 (phen CH),
150.3 (phen CH), 136.8 (phen CH), 131.0 (phen CH), 125.6 (cat
CH), 124.5 (cat CH), 124.1 (phen CH), 123.1 (phen CH), 119.4
(phen CH), 117.4 (cat CH), 62.4 (-O-CH3), 56.9 (-OCH3). UV-
vis (CH3CN/H2O 20:1): ꢀ270
) 26 000 dm3 mol-1 cm-1. Mp:
nm
108-110 °C. HR-CI-MS: m/z 360.1347 (calculated for
C21H18N3O3: 360.1348).
Synthesis of [Ru(bpy)2(Me2-L3)](PF6)2. Under an inert atmo-
sphere, Me2-L3 (0.20 g, 0.55 mmol) and cis-[RuCl2(bpy)2] × 2H2O
(0.25 g, 0.55 mmol) were dissolved in 35 mL of a EtOH/H2O 3:1
mixture and refluxed for 6 h. After cooling, the volume of the
solution was reduced by half, and the product was precipitated by
the addition of a saturated solution of ammonium hexafluorophos-
phate in water. The precipitate was isolated, washed with cold water
and ethanol, and dried in vacuo. Yield: 0.51 g (0.47 mmol, 94%).
1H NMR (500 MHz, CD3CN): δ 10.90 (s, 1H, NH), 9.07 (s, 1H,
phen CH), 8.68 (d, 1H, phen CH), 8.61 (d, 1H, phen CH), 8.53
(-OCH3), 56.4 (-OCH3). UV-vis (CH3CN/H2O, 20:1): ꢀ390
nm
) 3140 dm3 mol-1 cm-1. IR (THF): ν(CO) 2019, 1918, 1893 cm-1
.
Mp: 248-250 °C. HR-FAB-MS: m/z 686.0240 (calculated for
(30) Gran, G. Analyst 1952, 77, 661.
C24H17N3O6185Re Na: 686.0233).
6518 Inorganic Chemistry, Vol. 46, No. 16, 2007