B. Schäfer, H. Görls, S. Meyer, W. Henry, J. G. Vos, S. Rau
FULL PAPER
H, CH3 tert-butyl), 7.05 (d, J = 8 Hz, 4 H, phenylA), 7.25 (d, J
3
3
down. Afterwards the solution was filtered, and the solvent was
removed by rotary evaporation. The crude product was purified
using column chromatography [silica, CHCl3/heptane (v/v = 2)].
While the amount of heptane in the gradient was decreased, a violet
band and a red main band were gathered from the column. Switch-
ing the eluent to CHCl3/MeOH led to the collection of a brown
band. The red band was recrystallised from acetone and aqueous
3
= 8 Hz, 4 H, phenylA), 7.51 (d, J = 8.4 Hz, 4 H, phenylB), 7.57
3
(d, J = 8.4 Hz, 4 H, phenylB), 8.34 (s, 2 H, H4,H7-phen), 9.57 (s,
2 H, H2,H9-phen) ppm. MS (DEI, EI+Q1MS): m/z (%) = 709 (4)
[M+]. C52H56N2·1CH3OH (741.05): calcd. C 85.9, H 8.16, N 3.78;
found C 85.81, H 7.72, N 3.33.
Preparation of RuL2 and RuL3: Ru(tbbpy)2Cl2 (0.1 g, 0.14 mmol)
and the corresponding ligand (0.14 mmol) were suspended in
DMF/H2O (80 mL/10 mL) and heated at reflux for 3 h using mi-
crowave irradiation (150 W). Afterwards the reaction mixture was
filtered, and the solvent was removed under reduced pressure. The
complexes were recrystallised from a mixture of ethanol and aque-
ous NH4PF6, and further purified by column chromatography
using a stationary silica phase and a gradient changing from EtOH
to EtOH/H2O/KNO3. The novel ruthenium complexes based on
the aryl-substituted phenanthroline ligands did not yield satisfac-
tory elemental analysis results, which might be due to the presence
of multiple flexible substituents retaining varying amounts of sol-
vents.
1
NH4PF6 solution. Yield: 46%. H NMR (CD3CN, 400 MHz): δ =
1.24 (s, 54 H, CH3 tert-butyl), 1.29 (s, 54 H, CH3 tert-butyl), 7.23
3
(d, 3J = 8.4 Hz, 12 H, phenyl), 7.39 (d, J = 8.4 Hz, 12 H, phenyl),
4
8.20 [s(lc), 4J = 2 Hz, 6 H, phen], 8.47 [s(lc), J = 2 Hz, 6 H, phen]
ppm. MS (ESI, MeOH): m/z = 2372 ([M – PF6]+, 26% with match-
ing isotopic pattern), 1114.4 ([M – 2PF6]2+, 100% with matching
isotopic pattern).
Crystal Structure Determination: The intensity data for the com-
pound were collected with a Nonius KappaCCD diffractometer
using graphite-monochromated Mo-Kα radiation. Data were cor-
rected for Lorentz and polarisation effects but not for absorp-
tion.[37,38] The structures were solved by direct methods
(SHELRS[39]) and refined by full-matrix least-squares techniques
against Fo2 (SHELRL-97[40]). The hydrogen atoms of the structures
were included at calculated positions with fixed thermal param-
eters. All non-hydrogen atoms were refined anisotropically.[40] XP
(SIEMENS Analytical X-ray Instruments, Inc.) was used for struc-
ture representations. CCDC-617531 (L2) contains the supplemen-
tary crystallographic data for this paper. These data can be ob-
tained free of charge from The Cambridge Crystallographic Data
Centre via www.ccdc.cam.ac.uk/data_request/cif.
[Ru(tbbpy)2(L2)](PF6)2 (RuL2): Yield 84%. 1H NMR (CD3CN,
400 MHz): δ = 1.38 (s, 18 H, CH3 tert-butyl), 1.45 (s, 18 H, CH3
tert-butyl), 7.25–7.45 (m, 22 H, phenyl, H5-bpy), 7.52 (d, 3J = 6 Hz,
4J = 2 Hz, 2 H, H5Ј-bpy), 7.73 (d, J = 6 Hz, 2 H, H6-bpy), 7.83
3
(d, 3J = 6 Hz, 2 H, H6Ј-bpy), 8.00 (s, 4J = 1.6 Hz, 2 H, phen), 8.11
(s, 4J = 2 Hz, 2 H, phen), 8.49 (s, 4J = 2 Hz, 2 H, H3-bpy), 8.56 (s,
4J = 1.6 Hz, 2 H, H3Ј-bpy) ppm. MS (ESI, MeOH): m/z = 1267.5
([M – PF6]+, 100% with matching isotopic pattern).
[Ru(tbbpy)2(L3)](PF6)2 (RuL3): Yield: 70%. 1H NMR (CD3CN,
400 MHz): δ = 1.39 (s, 18 H, CH3 tert-butyl), 1.47 (s, 18 H, CH3
tert-butyl), 7.3–7.5 (m, 18 H, phenyl, H5-bpy), 7.55 [d(lc), 3J = 5.8,
4J = 1.8 Hz, 2 H, H5Ј-bpy], 7.58–7.70 (m, 20 H, phenyl), 7.77 (d,
3J = 6 Hz, 2 H, H6-bpy), 7.86 (d, 3J = 5.6 Hz, 2 H, H6Ј-bpy), 8.09
[s(lc), 4J = 2 Hz, 2 H, phen], 8.26 [s(lc), 4J = 2 Hz, 2 H, phen],
Crystal Data for L2: C36H24N2·2CHCl3, Mr = 723.31 gmol–1,
colourless prism, size 0.05ϫ0.05ϫ0.04 mm3, triclinic, space group
P1, a = 12.8649(8), b = 12.9330(6), c = 12.9950(7) Å, α = 64.525(3),
¯
β = 64.591(3), γ = 68.457(3)°, V = 1718.31(16) Å3, T = –90 °C, Z
= 2, ρcalcd. = 1.398 gcm–3, µ(Mo-Kα) = 5.31 cm–1, F(000) = 740,
12260 reflections in h(–16/16), k(–15/16), l(–14/16), measured in the
range 2.02° Յ Θ Յ 27.46°, completeness Θmax = 98.7%, 7758 inde-
4
4
8.517 [s(lc), J = 2 Hz, 2 H, H3-bpy], 8.58 [s(lc), J = 2 Hz, 2 H,
H3Ј-bpy] ppm. MS (ESI, MeOH): m/z = 1571.5 ([M – PF6]+, 74%),
713.3 ([M – 2PF6]2+, 100% with matching isotopic pattern).
pendent reflections, Rint = 0.0281, 5185 reflections with Fo
Ͼ
4σ(Fo), 415 parameters, 0 restraints, R1(obs) = 0.0527, wR2(obs) =
0.1134, R1(all) = 0.0933, wR2(all) = 0.1338, GOOF = 1.003, largest
difference peak and hole = 0.462/–0.492 eÅ–3.
Preparation of [Ru(tbbpy)2(L4)](PF6)2 (RuL4): Ru(tbbpy)2Cl2
(0.2 g, 0.282 mmol) and the corresponding ligand (0.282 mmol)
were suspended in EtOH/H2O (60 mL/20 mL) and heated at reflux
for 1 h using microwave irradiation (150 W). Afterwards the reac-
tion mixture was filtered. The work-up procedure used was the
same as that for RuL2 and RuL3. Yield: 89%. Silica and chloro-
form were used for column chromatography. 1H NMR (CD3CN,
400 MHz): δ = 1.27 (s, 18 H, CH3 tert-butyl), 1.28 (s, 18 H, CH3
tert-butyl), 1.38 (s, 18 H, CH3 tert-butyl), 1.46 (s, 18 H, CH3 tert-
Electronic Spectroscopy: UV/Vis absorption spectra (accuracy
Ϯ2 nm) were recorded with an Analytikjena Specord S 600 spec-
trometer with standard software-based tools. Emission spectra (ac-
curacy Ϯ5 nm) were recorded at 298 K using a Perkin–Elmer
LS50B luminescence spectrophotometer, which was equipped with
a red-sensitive Hamamatsu R298 PMT detector and interfaced
with an Elonex PC466 employing Perkin–Elmer FlWinLab custom-
built software. Emission spectra are uncorrected for photomulti-
plier response. 10-mm path length quartz cells were used for re-
cording spectra.
3
4
3
butyl), 7.15 (d, J = 8 Hz, J = 1.8 Hz, 2 H, phenylA), 7.22 (d, J
= 8 Hz, 4J = 1.6 Hz, 2 H, phenylA), 7.25 (d, 3J = 8.4 Hz, 4 H,
3
4
phenylB), 7.31 (d, J = 6.4 Hz, J = 2 Hz, 2 H, H5-bpy), 7.36 (d,
3J = 8.4 Hz, J = 1.8 Hz, 2 H, phenylA), 7.40 (d, J = 8 Hz, J =
4
3
4
2.2 Hz, 2 H, phenylA), 7.44 (d, 3J = 8.8 Hz, 4 H, phenylB), 7.53
Emission Lifetime Measurements: Luminescence lifetime measure-
ments were obtained using an Edinburgh Analytical Instruments
(EAI) time-correlated single photon counting apparatus (TCSPC)
comprised of two model J-yA monochromators (emission and exci-
tation), a single photon photomultiplier detection system model
5300 and a F900 nanosecond flashlamp (nitrogen filled at 1.1 atm
pressure, 40 kHz or 0.3 atm pressure, 20 kHz) interfaced with a per-
sonal computer by a NorlandMCA card. A 410 nm cut-off filter
was used in emission to attenuate scatter of the excitation light
(337 nm); luminescence was monitored at the kmax of the emission.
Data correlation and manipulation was carried out using EAI F900
software version 6.24. Samples were de-aerated using argon for
30 min prior to measurements, followed by repeated purging to en-
3
4
3
(d, J = 6, J = 2 Hz, 2 H, H5Ј-bpy), 7.72 (d, J = 6 Hz, 2 H, H6-
bpy), 7.84 (d, J = 6 Hz, 2 H, H6Ј-bpy), 7.95 (s, 4J = 2 Hz, 2 H,
3
4
4
H4,H7-phen), 8.12 (s, J = 1.6 Hz, 2 H, H2,H9-phen), 8.49 (s, J
4
= 1.6 Hz, 2 H, H3-bpy), 8.55 (s, J = 1.6 Hz, 2 H, H3Ј-bpy) ppm.
MS (ESI, MeOH): m/z = 1491.5 ([M – PF6]+, 100% with matching
isotopic pattern), 673.3 ([M – 2PF6]2+, 55% with matching isotopic
pattern).
Synthesis of the Homoleptic Complex of L4, [Ru(L4)3](PF6)2
[Ru(L4)3]: A mixture of RuCl3·3H2O (0.012 g, 45.9 µmol) and L4
(0.101 g, 0.143 mmol) was suspended in ethanol (30 mL), methanol
(20 mL), DMF (15 mL) and water (15 mL). The reaction mixture
was refluxed in a microwave oven for 3 h at 200 W and cooled
4062
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Eur. J. Inorg. Chem. 2007, 4056–4063