Sheng Hua Liu et al.
compound 2b (2.0 g, 6.94 mmol), CuI (64 mg, 0.35 mmol), [Pd
(PPh3)4]
nation of direct methods (SHELXS-97)[33] and Fourier difference tech-
niques and were refined by full-matrix least-squares (SHELXL-97).[34]
All non-H atoms were refined anisotropically. The hydrogen atoms were
placed at ideal positions and refined as riding atoms. The solvent mole-
cules in compound 1c could not be refined because of their highly disor-
dered structure. Therefore, the SQUEEZE function of the PLATON
program was used to eliminate the contribution of the electron density in
the solvent region from the intensity data.[37] The contribution of these
species was removed and final refinement was performed. Partial solvent
molecules were omitted. Further crystal data and details of the data col-
lection are summarized in the Supporting Information, Table S1. Selected
bond lengths and angles are given in Table 1. CCDC 941574 (1c) contains
the supplementary crystallographic data for this paper. These data can be
obtained free of charge from The Cambridge Crystallographic Data
(803 mg, 0.69 mmol), triethylamine (60 mL), THF (100 mL), and (trime-
thylsilyl)acetylene (2.04 g, 20.8 mmol). Yield: 1.62 g (65%); light-yellow
solid; 1H NMR (400 MHz, CDCl3): d=0.24 (s, 18H; SiCH3), 6.99 (d, J=
3.6 Hz, 2H; thiophene-H), 7.12 ppm (d, J=3.6 Hz, 2H; thiophene-H).
5,5’’-Bis(trimethylsilylethynyl)-2,2’:5’,2’’-terthiopheneACTHNUTRGNE(UNG 3c): The procedure
for the synthesis of compound 3c was similar to that for compound 3a,
with compound 2c (0.7 g, 1.72 mmol), CuI (33 mg, 0.17 mmol), [Pd-
ACHTUNGTRENNUNG(PPh3)4] (199 mg, 0.17 mmol), (iPr)2NH (30 mL), THF (30 mL), and (tri-
methylsilyl)acetylene (675 mg, 6.89 mmol). Yield: 300 mg (59%); light-
yellow solid; 1H NMR (400 MHz, CDCl3): d=0.26 (s, 18H; SiCH3), 7.01
(d, J=4.0 Hz, 2H; thiophene-H), 7.07 (s, 2H; thiophene-H), 7.13 ppm (d,
J=4.0 Hz, 2H; thiophene-H).
Synthesis of the Binuclear Ruthenium Complexes
Physical Measurements
Compound 1a: A solution of [Cp*ACHTNUTRGNE(NUG dppe)RuCl] (387 mg, 0.58 mmol), 2,5-
bis(trimethylsilylethynyl)thiophene (3a, 80 mg, 0.29 mmol), and KF
(202 mg, 3.47 mmol) in MeOH (20 mL) and THF (5 mL) was heated at
reflux under a nitrogen atmosphere for 24 h. The crude product was col-
lected by filtration and washed with MeOH and n-hexane. The solid was
dissolved in CH2Cl2 and precipitated by slow diffusion with n-hexane.
The solid was filtered and dried to give compound 1a as an red-brown
powder (250 mg, 60%). 1H NMR (400 MHz, CDCl3): d=1.54 (s, 30H;
1H, 13C, and 31P NMR spectra were collected on a Varian Mercury Plus
400 spectrometer (400 MHz). 1H and 13C NMR chemical shifts are report-
ed relative to TMS and 31P NMR chemical shifts are reported relative to
85% H3PO4. Elemental analysis was performed on a Vario ElIII Chnso
instrument. UV/Vis/NIR spectra were recorded on a Shimadzu UV-3600
UV/Vis/NIR spectrophotometer by using liquid sample cells (path
length: 200 mm). IR spectra was recorded on a Nicolet Avatar spectrome-
ter from Nujol mulls that were suspended between KBr discs and liquid
sample cells (path length: 200 mm). The electrochemical measurements
were performed on a CHI 660C potentiostat (CHI USA). A three-elec-
trode one-compartment cell was used to contain the solution of com-
plexes and supporting electrolyte in dry CH2Cl2. De-aeration of the solu-
tion was achieved by bubbling argon gas through the solution for about
10 min before the measurements. The concentrations of the ligand and
the electrolyte (nBu4NPF6) were typically 0.001 and 0.1 moldmꢀ3, respec-
tively. A platinum disk working electrode (diameter: 500 mm), a platinum
wire counter electrode, and a Ag/Ag+ reference electrode were used. The
2ꢂC5ACHTUNGTRENNUNG(CH3)5), 2.04 (br s, 4H; CH2/dppe), 2.67 (br s, 4H; CH2/dppe), 7.20–
7.37 (m, 32H+2H;
H
Ar/dppe+Hthiophene), 7.77 ppm (br s, 8H; HAr/dppe);
13C NMR (100 MHz, CDCl3): d=9.94 (CH3), 29.42 (t, J=22.80 Hz; CH2/
dppe), 92.62 (CH/C5Me5), 101.66 (thiophene-C), 123.65 (Ru-C), 127.28,
128.75, 133.24, 133.71, 136.77, 137.16, 138.84 ppm; 31P NMR (160 MHz,
CDCl3): d=78.01 ppm (dppe); IR (KBr): n˜ =2064 cmꢀ1 (w, C C); ele-
mental analysis calcd (%) for C80H80P4Ru2S: C 68.65, H 5.76; found:
C 68.63, H 5.77.
ꢁ
Compound 1b: The procedure for the synthesis of compound 1b was
similar to that for compound 1a, with [Cp*ACTHNUTRGNEUNG(dppe)RuCl] (275 mg,
0.41 mmol), 5,5’-bis(trimethylsilylethynyl)-2,2’-bithiophene (3b, 70 mg,
0.20 mmol), KF (136 mg, 2.35 mmol), MeOH (20 mL), and THF (5 mL).
Yield: 130 mg (44%); light-yellow solid; 1H NMR (400 MHz, CDCl3):
Ag/Ag+ reference electrode contained
a 0.01m AgNO3 solution in
CH3CN. Chemical oxidation experiments of the charge-neutral molecules
were carried out: Monocationic and dicationic forms were affected by
ferrocenium hexafluorophosphate, in accord with the results of the elec-
trochemical oxidation. EPR spectroscopy was performed on a Bruker
BioSpin GmbH, by using a microwave frequency of about 9.84 GHz,
a modulation frequency of 100 kHz, a modulation amplitude of 1 G, and
about a microwave power 20 mW.
d=1.59 (s, 30H; 2ꢂC5ACHTUNGTRENNUNG(CH3)5), 2.05 (br s, 4H; CH2/dppe), 2.65 (br s, 4H;
CH2/dppe), 7.22–7.38 (m, 32H+4H; HAr/dppe+Hthiophene), 7.74 ppm (br s,
8H; HAr/dppe); 31P NMR (160 MHz, CDCl3): d=79.90 ppm (dppe); IR
(KBr): n˜ =2056 cmꢀ1 (w, C C); elemental analysis calcd (%) for
ꢁ
C84H82P4Ru2S2: C 68.09, H 5.58; found: C 68.21, H 5.34. Note: This com-
pound has poor solubility in many deuterated solvents, including CDCl3,
in which the 13C NMR spectrum could not be recorded.
Computational Details
Compound 1c: The procedure for the synthesis of compound 1c was sim-
ilar to that for compound 1a, with [Cp*ACTHNUTRGNEUNG(dppe)RuCl] (319 mg,
DFT calculations were performed by using the Gaussian 03 and 09 pro-
grams at the B3LYP/3-21G* level of theory. Geometry optimizations
were performed without any symmetry constraints and frequency calcula-
tions on the resulting optimized geometries showed no imaginary fre-
quencies. Electronic transitions were calculated by using the time-depen-
dent DFT (TDDFT) method. The MO contributions were generated by
using the Multiwfn2.6.1_bin_Win package and plotted by using Gauss-
View 5.0.
0.48 mmol), 5,5’’-bis(trimethylsilylethynyl)-2,2’:5’,2’’-terthiophene (3c,
100 mg, 0.23 mmol), KF (158 mg, 2.72 mmol), MeOH (20 mL), and THF
(5 mL). Crystals suitable for X-ray crystallography were grown from the
slow diffusion of n-hexane into a solution of compound 1c in CH2Cl2.
Yield: 190 mg (54%); purple power; 1H NMR (400 MHz, CDCl3): d=
1.55 (s, 30H; 2ꢂC
CH2/dppe), 6.18(s, 2H; thiophene), 6.77
(CH3)5), 2.05 (br s, 4H; CH2/dppe), 2.67 (br s, 4H;
(d, J(H,H)=3.6 Hz, 2H; thio-
N
ACHTUNGTRENNUNG
phene), 6.81(s, 2H; thiophene), 7.20–7.37(m, 32H; HAr/dppe), 7.74 ppm
(br s, 8H; HAr/dppe); 13C NMR (100 MHz, CDCl3): d=10.11 (CH3), 29.59
(t, J=22.80 Hz, CH2/dppe), 92.86 (CH/C5Me5), 102.32 (thiophene-C),
122.41, 122.67, 122.87, 125.10 (Ru-C), 127.58, 128.97, 129.17, 130.69,
131.90, 133.24, 133.39, 133.73, 135.79, 136.00, 136.33, 136.53, 136.80,
137.01, 138.49, 138.82, 141.29 ppm; 31P NMR (160 MHz, CDCl3): d=
Acknowledgements
The authors acknowledge financial support from the National Natural
Science Foundation of China (20931006, 21072070, 21072071, and
21272088), the Program for Changjiang Scholars and Innovative Re-
search Team in University (IRT0953), and the Program for Academic
Leader in Wuhan Municipality (201271130441).
79.93 ppm (dppe); IR (KBr): n˜ =2046 cmꢀ1 (w, C C); elemental analysis
ꢁ
calcd (%) for C88H84P4Ru2S3: C 67.59, H 5.41; found: C 67.71, H 5.26.
Crystallographic Details
Single crystals of complex 1c suitable for X-ray analysis were obtained
by the slow diffusion of n-hexane into a solution in CH2Cl2. Crystals with
approximate dimensions of 0.16ꢂ0.12ꢂ0.10 mm3 were mounted onto
glass fibers for the diffraction experiments. Intensity data were collected
on a Nonius Kappa CCD diffractometer with MoKa radiation (0.71073 ꢁ)
at low temperatures (100 K). The structure was solved by using a combi-
Chem. Asian J. 2013, 8, 2023 – 2032
2031
ꢀ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim