C.S.K. Mak et al. / Journal of Organometallic Chemistry 694 (2009) 2770–2776
2775
Bis((4-trifluoromethyl)phenylimino)acenaphthene 3e: (58%). 1H
NMR (300 MHz, CDCl3): d = 7.97 (d, J = 8.2 Hz, 2H), 7.76 (d,
J = 8.3 Hz, 4H), 7.44 (t, J = 7.8 Hz, 2H), 7.23 (d, J = 8.2 Hz, 4H), 6.85
(d, J = 7.2 Hz, 2H). 13C NMR (100 MHz, CDCl3): d = 161.3, 154.4,
142.0, 131.3, 129.7, 127.9, 126.8, 124.2, 118.3; MS (EI): m/z: 469
[M]+.
(e
) = 517 nm (4100 dm3 molꢀ1 cmꢀ1). MS (FAB-MS): m/z: 774
[M]+, 739 [MꢀCl]+. Anal. Calc. for C29H14N2ClF6O3Re: C, 45.00; H,
1.82; N, 3.62. Found: C, 44.73; H, 1.77; N, 3.27%.
4.4. Measurements
1H and 13C NMR spectra (1H NMR 298 K, 13C NMR 298 K) were
collected on a Bruker AM-500 (500-MHz), a Bruker AV-400 (400-
MHz) or a Bruker DPX-300 (300-MHz) multinuclear Fourier trans-
form nuclear magnetic resonance (NMR) spectrometers. Chemical
shifts (d) are reported in ppm relative to tetramethylsilane (TMS)
as the internal standard and coupling constants (J) in Hz. Multiplic-
ities are reported as singlet (s), doublet (d), triplet (t), quartet (q),
and multiplet (m). Fourier transform infrared (FTIR) spectra were
recorded as KBr pellet on a Bio-Rad FTS-7 FTIR spectrometer
(4000–400 cmꢀ1) and are reported in cmꢀ1. UV–Visible absorption
spectra were recorded on a Hewlett–Packard 8452A diode array
UV–Visible spectrophotometer or a Varian Cary 50 UV–Visible
spectrophotometer. Positive ion FAB mass spectra were recorded
on a Finnigan MAT95 mass spectrometer. Thermal analyses were
performed on Perkin Elmer TGA7 thermal analyzers. The thermo-
gravimetric analysis (TGA) was performed under a nitrogen atmo-
sphere with the heating rate of 15 °C minꢀ1. Cyclic voltammetry
(CV) was performed on a Princeton Applied Research 270 potentio-
stat. A conventional three-electrode system was adopted, which
consisted of a glassy carbon working electrode and two platinum
electrodes as the counter and reference electrodes. The salt bridges
of reference electrode and counter electrode compartments were
separated from the working electrode compartment by a vycor
glass. Cyclic voltammograms were recorded at a scan rate of
100 mV/s. HPLC grade acetonitrile was used as the solvent and tet-
rabutylammonium tetrafluoroborate (0.1 M) was used as the sup-
porting electrolyte. Ferrocene was added as the internal standard.
For the DFT calculations, GAUSSIAN98 program was used. The density
functional theory calculations for the ground state of the com-
plexes were performed by using B3LYP method with a LanL2DZ ba-
sis set.
4.3. Synthesis of complexes (4a–e)
Synthesis of chlorotricarbonyl bis(4-methoxyphenylimino)ace-
naphthene rhenium(I) 4a: Under a nitrogen atmosphere, a mixture
of 3a (0.8 g, 2 mmol) and rhenium pentacarbonyl chloride (0.8 g,
2 mmol) in toluene (15 ml) was heated under reflux for 24 h. After
cooling, the solid was filtered off and washed with toluene, ether,
and then dried under vacuum. The product was collected as
brownish solid. (1.3 g, 87%). Td = 336 °C; 1H NMR (400 MHz,
CDCl3): d = 8.05 (d, J = 8.2 Hz, 2H), 7.65 (m, 2H), 7.51 (t, J = 7.8 Hz,
2H), 7.32 (m, 2H), 7.17 (d, J = 7.3 Hz, 2H), 7.11 (dd, J = 1.5, 7.6 Hz,
2H), 3.96 (s, 6H); 13C NMR (125 MHz, CDCl3): d = 196.0, 186.3,
159.6, 144.8, 142.2, 131.4, 130.9, 129.0, 128.5, 128.2, 126.4,
125.3, 124.6, 123.1, 121.7, 115.0, 55.6; FTIR (KBr pellet):
m
= 2020, 1921, 1888 cmꢀ1 (metal carbonyl CO stretching); UV–
Vis (CHCl3): kmax (e
) = 493 nm (7200 dm3/mol cm); MS (FAB): m/z
(%): 698 [M]+, 663 [MꢀCl]+. Anal. Calc. for C29H20N2ClO5Re: C,
49.89; H, 2.89; N, 4.01. Found: C, 49.66; H, 2.54; N, 4.17%.
Chlorotricarbonyl bis(4-methylphenylimino)acenaphthene rhe-
nium(I) 4b: (83%). 1H NMR (300 MHz, CDCl3): d = 8.07 (d,
J = 8.3 Hz, 2H), 7.62 (d, J = 6.2 Hz, 2H), 7.52 (t, J = 7.8 Hz, 2H), 7.43
(d, J = 8.6 Hz, 4H), 7.11 (d, J = 7.3 Hz, 2H), 7.09 (d, J = 8 Hz, 2H),
2.53 (s, 6H). 13C NMR (125 MHz, CDCl3): d = 196.0, 186.2, 172.8,
146.6, 144.9, 138.6, 131.4, 131.0, 130.8, 130.3, 128.5, 126.3,
124.8, 121.3, 119.9, 21.4. FTIR (KBr pellet):
(metal carbonyl CO stretching). UV–Vis (CHCl3): kmax
m
= 2026, 1920 cmꢀ1
(e
) = 499 nm (11 000 dm3 molꢀ1 cmꢀ1). MS (FAB-MS): m/z: 667
[M]+, 632 [MꢀCl]+. Anal. Calc. for C29H20N2ClO3Re: C, 52.29; H,
3.03; N, 4.21. Found: C, 51.94; H, 2.88; N, 4.06%.
Chlorotricarbonyl bis(phenylimino)acenaphthene rhenium(I) 4c:
(96%). 1H NMR (400 MHz, CDCl3): d = 8.06 (d, J = 8.2 Hz, 2H), 7.73
(d, J = 8.3 Hz, 2H), 7.63 (t, J = 8.0 Hz, 4H), 7.51 (t, J = 7.3 Hz, 2H),
7.48 (d, J = 8.1 Hz, 2H), 7.38 (d, J = 8.1 Hz, 2H), 7.00 (d, J = 7.3 Hz,
2H). 13C NMR 125 MHz, CDCl3): d = 195.8, 186.0, 173.0, 148.9,
145.0, 131.4, 131.1, 130.4, 129.9, 129.0, 128.6, 128.2, 126.2,
4.5. Carrier mobility measurements
The thin film for charge carrier mobility measurement was fab-
ricated by evaporating the material on an ITO coated glass sub-
strate under vacuum. Typical thickness of the thin film was
approximately 500 nm. A layer of 100 nm metal electrode was
coated on the organic film surface by thermal evaporation. Charge
carrier mobility was determined by the time-of-flight experiment
[31]. A Laser Science VSL-337 nitrogen laser was used to generate
124.8, 121.3, 120.0. FTIR (KBr pellet):
m
= 2019, 1921 cmꢀ1 (metal
) = 503 nm
carbonyl CO stretching). UV–Vis (CHCl3): kmax
(e
(7500 dm3 molꢀ1 cmꢀ1); MS (FAB-MS): m/z: 638 [M]+, 603
[MꢀCl]+. Anal. Calc. for C27H16N2ClO3Re: C, 50.82; H, 2.53; N,
4.39. Found: C, 50.43; H, 2.21; N, 4.11%.
Chlorotricarbonyl bis(4-fluorophenylimino)acenaphthene rhe-
nium(I) tricarbonyl chloride 4d: (90%). 1H NMR (300 MHz, CDCl3):
d = 8.10 (d, J = 8.2 Hz, 2H), 7.57 (m, 2H), 7.54 (td, J = 1.1, 7.8 Hz,
2H), 7.30 (m, 6H), 7.07 (d, J = 7.3 Hz, 2H); 13C NMR (125 MHz,
CDCl3): d = 195.6, 185.7, 173.4, 163.2, 161.2, 145.1, 144.9, 131.5,
131.4, 129.6, 128.7, 126.0, 124.8, 123.5, 123.4, 121.9, 121.8,
a pulsed laser source (wavelength = 337 nm, pulse energy = 120 lJ,
and pulse width full width at half-maximum (fwhm) = 3 ns). The
transient photocurrent profiles were recorded with an oscilloscope
(Tektronix TDS 3052B).
4.6. Photovoltaic device characterizations
117.6, 117.4, 117.1, 116.9; FTIR (KBr pellet):
(metal carbonyl CO stretching). UV–Vis (CHCl3): kmax
m
= 2022, 1906 cmꢀ1
The ITO coated glass substrates with sheet resistance of 15
X/
(
e
) = 508 nm (9000 dm3 molꢀ1 cmꢀ1). MS (FAB-MS): m/z: 675
square (Tinwell Technology Ltd.) were cleaned prior to use. The
substrates were rinsed with toluene, ethanol, and acetone in se-
quence. It was then cleaned in an ultrasonic bath for 8 min in a
3% Decon 90 glass–detergent solution, 8 min in ultrapure water
[M]+, 640 [MꢀCl]+. Anal. Calc. for C27H14N2ClF2O3Re: C, 48.11; H,
2.09; N, 4.16. Found: C, 47.83; H, 1.96; N, 4.23%.
Chlorotricarbonyl
bis((4-trifluoromethyl)phenylimino)acenaph-
thene rhenium(I) 4e: (92%). 1H NMR (400 MHz, CDCl3): d = 8.14 (d,
J = 8.3 Hz, 2H), 7.93 (d, J = 8.5 Hz, 4H), 7.87 (d, J = 8.4 Hz, 2H),
7.57 (t, J = 7.8 Hz, 2H), 7.50 (d, J = 7.3 Hz, 2H), 6.99 (d, J = 7.3 Hz,
2H). 13C NMR (125 MHz, DMSO-d6): d = 196.8, 185.9, 173.6,
151.3, 144.9, 132.3, 131.1, 129.0, 128.4, 125.2, 124.8, 122.8,
(18.2 MX), 5 min in ethanol, and 5 min in acetone in sequence.
The substrates were rinsed thoroughly with ultrapure water after
each cleaning step. All the solvents used for cleaning were analyt-
ical grade. The substrates were dried under a nitrogen atmosphere.
Before the ITO substrates were loaded into an evaporator, it was
treated with UV ozone for 15 min. The multilayer photovoltaic de-
vices were fabricated by evaporating different organic materials on
121.8, 121.3, 112.7. FTIR (KBr pellet):
(metal carbonyl CO stretching). UV–Vis (CHCl3): kmax
m
= 2028, 1930, 1897 cmꢀ1