2
S.-H. Li et al. / Polyhedron 173 (2019) 114109
regions were collected with the PerkinElmer Lambda 950 UV–vis–
NIR spectrophotometer. The electrochemical experiments were
measured under argon by V3-Studio in the dichloromethane solu-
tions which promoting electrolyte is 0.1 M (Bu4N)PF6 at a scan rate
of 100 mV sꢀ1. The electrolytic cell consists of glassy graphite, plat-
inum and Ag/AgCl as working, counter and reference electrode,
respectively. The single-crystal X-ray diffraction data for all these
complexes were collected on a Saturn724 + CCD diffractometer
MeCp(dppe)RuIICN was similar to that for MeCp(PPh3)2RuIICN by
using MeCp(dppe)RuIICl instead of MeCp(PPh3)2RuIICl. Yield:
0.54 mg; 56%. IR (KBr, cmꢀ1): 2071 (C„N).
3.2.4. Preparation of [MeCp(dppe)RuII( -CN)FeII(dppe)Cp](PF6), 1
l
[PF6]
Under argon atmosphere, Cp(dppe)Fe(NCCH3)Br (0.22 g,
0.34 mmol) was added to a solution of MeCp(dppe)RuCN (0.20 g,
0.331 mol) in CH3OH (25 ml), resulting a claret solution. After stir-
ring for 6 h at 50 °C, NH4PF6 (0.08 g, 0.500 mol) was introduced to
the solution and the reaction proceeds for extra one hour. Then the
solution was filtered and the obtained solid was washed by diethyl
ether. The product was crystallized from the diethyl ether and
dichloromethane at room temperature as the claret crystals
(0.31 g, 72%). Elemental analysis calcd (%) for 1[PF6]: C, 59.31; H,
4.59; N, 1.06. Found: C, 57.95; H, 4.51; N, 1.06. IR (KBr, cmꢀ1):
2081 (C„N).
equipped with graphite monochromatic Mo K
a (k = 0.71073 Å)
radiation by using an -scan model technique at 293 K. All crystal-
x
lographic structures were solved by direct methods using SHELXL-
2014/7 and refined with Olex 2 program package [30,31].
3. Materials and synthesis
3.1. Materials
All operations were conducted in an argon atmosphere through
the standard Schlenk techniques useless extra stated. Cp(dppe)Fe
(NCCH3)Br (dppe = bis(diphenylphosphino)ehane, Cp = cyclopenta-
dienyl) was prepared by the previous literature [32]. Dichloro-
methane for CV was dried by distillation over calcium hydride
under nitrogen atmosphere. Methanol was dried by distillation
over magnesium. All other reactants were purchased commercially
and used directly without further purification.
3.2.5. Preparation of [MeCp(dppe)RuII( -CN)FeIII(dppe)Cp](PF6)2, 1
l
[PF6]2
To a 20 ml dichloromethane solution of 1 (0.31 g, 0.235 mol)
was added 1 equiv of (Cp)2FePF6 (0.08 g, 0.242 mol). At room tem-
perature, the mixture solution was stirred for 2 h. The solution was
filtered and the solvent was condensed to 3 ml under reduced
pressure. A large amount of diethyl ether was added and the pro-
duct was formed as a precipitate. The product was obtained in
diethyl ether and dichloromethane at room temperature as the
dark red crystals (0.30 g, 88.2%). Elemental analysis calcd (%) for
1[PF6]2: C, 54.52; H, 4.16; N, 0.96. Found: C, 54.43; H, 4.20; N,
0.83. IR (KBr, cmꢀ1): 2015 (C„N).
3.2. Synthesis
3.2.1. Preparation of MeCp(PPh3)2RuIICl
Under argon atmosphere, the compound of methylcyclopenta-
diene dimer (Scheme 1) was heated to decomposition at 230 °C
and then collected the product. The other procedures are similar
to that for Cp(PPh3)2RuIICl [33], excepting that the decomposition
product replaces cyclopentadiene. The ethanol (30 ml) solution
with PPh3 (4.04 g, 15 mmol) was stirred for 15 min. Then, RuCl3
(1.00 g, 4.82 mmol) and methylcyclpentadiene (5 ml) were added.
The solution was refluxed for 4 h until a large amount of yellow
precipitate generated. The yellow solid, MeCp(PPh3)2RuIICl
(MeCp = methylcyclopentadiene), was filtered, washed with
methanol and hexanes. Yield: 1.85 g; 63%.
3.2.6. Preparation of [MeCp(PPh3)2RuII( -CN)FeII(dppe)Cp](PF6), 2
l
[PF6]
Under argon atmosphere, Cp(dppe)Fe(NCCH3)Br (0.17 g,
0.265 mol) was added to a solution of MeCp(PPh3)2RuCN (0.20 g,
0.273 mol) in CH3OH (25 ml). After stirring for 6 h at 50 °C, NH4PF6
(0.06 g, 0.368 mol) was introduced to the solution and the reaction
proceeds for another one hour. The solvent was removed under
reduced pressure totally, and the obtained solid was dissolved in
a small amount of dichloromethane, and layered by diethyl ether
at room temperature. The orange crystals (0.28 g, 77.8%) were
obtained. Elemental analysis calcd (%) for 2[PF6]: C, 63.71; H,
4.77; N, 1.00. Found: C, 64.64; H, 4.70; N, 0.97. IR (KBr, cmꢀ1):
2069 (C„N).
3.2.2. Preparation of MeCp(PPh3)2RuIICN
KCN (2.58 g, 39.62 mmol) was added to a solution of MeCp
(PPh3)2RuIICl (2.14 g, 3 mmol) in methanol(20 ml). The solution
was refluxed until a large amount of golden-yellow solid gener-
ated. The precipitate was collected, washed with methanol, water
and ethyl ether, giving the yellow product (1.73 g, 79%). IR (KBr,
cmꢀ1): 2061 (C„N).
3.2.7. Preparation of [MeCp(PPh3)2RuII( -CN)FeIII(dppe)Cp](PF6)2, 2
l
[PF6]2
To a 20 ml dichloromethane solution of 3 (0.35 g, 0.251 mol)
was added 1 equiv of (Cp)2FePF6 (0.1 g, 0.302 mol). At room tem-
perature, the mixture solution was stirred for 2 h. After that, the
solution was concentrated to 3 ml under reduced pressure and
then 70 ml diethyl ether was added, giving a precipitate. The pro-
duct was obtained in diethyl ether and dichloromethane at room
temperature as the dark green crystals (0.33 g, 84.6%). Elemental
analysis calcd (%) for 2[PF6]2: C, 51.70; H, 3.72; N, 0.78. Found: C,
51.81; H, 3.74; N, 0.73. IR (KBr, cmꢀ1): 1986 (C„N).
3.2.3. Preparation of MeCp(dppe)RuIICN
1.2 equiv of dppe (0.8 g, 2.0 mmol) was added to a solution of
MeCp(PPh3)2RuIICl (1.17 g, 1.60 mmol) in toluene (30 ml). The mix-
ture was refluxed overnight. The resulting solution was purified by
chromatograph. Evaporation of the obtained eluate gave the
orange crystals of MeCp(dppe)RuIICl. The synthetic procedure of
4. Results
4.1. X-ray structure determination
The crystallographic structures of complexes 1+, 2+ and their
one-electron oxidation products 12+, 22+ were determined at room
teꢀmperature by single crystal X-ray analysis. The space groups are
Scheme 1. The molecular structure of methylcyclopentadiene dimer.
P 1 for 1+ and 22+, P21/n for 12+, and Cc for 2+, respectively. It should