N. Panziera et al. / Journal of Organometallic Chemistry 691 (2006) 2648–2656
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conditions: infusion at 20 ll/min (Syringe Pump Harvard
mod. 22); CUR, 10; GS1, 25; GS2, 25; IS Voltage, 5 kV;
Turbo T, 300 ꢁC; DP, 20 V; the samples were prepared dis-
solving the complex in a toluene–methanol mixture.
H, 6.71%. IR m(C„C): 2156, 804 cmꢀ1; UV (CHCl3):
278.0, 292.1 nm. 1H and 13C NMR and mass data are
reported in Table 1.
FTIR spectra were recorded as nujol mulls or as films
deposited by CHCl3 solutions by using CsI cells, on a Per-
kin–Elmer 1700X Fourier Transform spectrometer. UV–
Vis spectra were recorded on Perkin–Elmer Lambda 16
instrument. XPS spectra were obtained using a custom
designed spectrometer. A non monochromatised Mg Ka
X-rays source (1253.6 eV) was used and the pressure in
the instrument was maintained at 1 · 10ꢀ9 Torr through-
out the analysis. The experimental apparatus consists of
an analysis chamber and a preparation chamber separated
by a gate valve. An electrostatic hemispherical analyser
(radius 150 mm) operating in the fixed analyser transmis-
sion (FAT) mode and a 16-channel detector were used.
The film samples were prepared by dissolving our materials
in CHCl3 and spinning the solutions onto polished stainless
steel substrates. The samples showed sufficient stability
during the XPS analysis, preserving the same spectral fea-
tures and chemical composition; the sampling of the thin
film was carried out in Ar atmosphere. Binding energies
(B.E.) were corrected by adjusting the position of the C1s
peak to 284.70 eV of the aromatic carbons, in agreement
with literature data [17]. The C1s, Ru3d, Si2p spectra were
deconvoluted into their individual peaks using the Peak Fit
curve fitting program for PC. Quantitative evaluation of
the atomic ratios was obtained by analysis of the XPS sig-
nal intensity, employing Scofield’s atomic cross section val-
ues [18] and experimentally determined sensitivity factors.
Microanalyses were carried out by the Laboratorio di
5.2. Preparation of Ru[g6-4,40-bis(trimethylsilylethynyl)-
biphenyl](g4-COD), 4b1
The reaction was performed as reported in Section 5.1.
4,40-Bis(trimethylsilylethynyl)biphenyl (DEBP-Si) (0.26 g,
0.74 mmol), 3b, was added to a solution of 1 (0.25 g,
0.74 mmol) and acetonitrile (0.77 ml, 14.8 mmol) in THF
(5 ml). The mixture was stirred at r.t. for 5 h and chro-
matographed on alumina. Toluene eluted a yellow-brown
fraction from which, by crystallization with a toluene/pen-
tane mixture, complex 4b1 was obtained (0.33 g, yield
80%). Anal. Calc. for C30H38Si2Ru: C, 64.85; H, 6.85.
Found: C, 64.13; H, 6.54%. IR m(C„C): 2158, 804 cmꢀ1
;
1
UV (CHCl3): 289.0 nm. H and 13C NMR and mass data
are reported in Table 1.
5.3. Preparation of Ru2 (g4-COD)2 [g6,g6-4,40-bis-
(trimethylsilylethynyl)biphenyl], 4b2
The reaction was performed as reported in Section 5.1.
4,40-Bis(trimethylsilylethynyl)biphenyl (DEBP-Si) (0.13 g,
0.37 mmol), 3b, was added to a solution of 1 (0.25 g,
0.74 mmol) and acetonitrile (0.77 ml, 14.8 mmol) in THF
(5 ml). The mixture was stirred at r.t. for 4 days. A large
amount of solid materials was formed. The solvent was
removed under vacuum and the residue was extracted with
toluene (5 ml). The yellow-brown solution was chromato-
graphed on an alumina column (20 cm, activity grade
III). Toluene eluted a yellow-brown fraction which was
evaporated to dryness. The solid was purified by crystalli-
zation at ꢀ78 ꢁC from THF-pentane, furnishing complex
4b2 as yellow-brown crystals (0.056 g, yield 20%). Anal.
Calc. for C38H50Si2Ru2: C, 59.65; H, 6.59. Found: C,
59.22; H, 6.34%. IR m(C„C): 2158, 804 cmꢀ1; UV
`
`
Microanalisi, Facolta di Farmacia, Universita di Pisa,
Italy.
5.1. Preparation of Ru[g6-1,4-bis(trimethylsilylethynyl)-
benzene](g4-COD), 4a
1
1,4-Bis(trimethylsilylethynyl)benzene (DEB-Si) (0.2 g,
0.74 mmol), 3a, was added to a solution of 1 (0.25 g,
0.74 mmol) in THF (5 ml). Acetonitrile (0.77 ml,
14.8 mmol) was then added and the mixture was stirred
at room temperature. The progress of the reaction was
checked by removing a liquid sample of the solution and
analysing the residue, obtained after evaporation of the
(CHCl3): 282.1 nm. H and 13C NMR and mass data are
reported in Table 1.
5.4. Preparation of the complexes Ru(g6-arene)(g4-COD),
5a [arene = 1,4-diethynylbenzene] and 5b1 [arene = 4,40-
bis(ethynyl)biphenyl]. General procedure
1
reaction solvent, by H NMR spectroscopy. The reaction
A
solution of Ru(g6-arene)(g4-COD) [arene = 1,
was stopped after 6 h when the spectrum showed the disap-
pearance of the signals of 1. The solvent was removed
under vacuum and the residue was dissolved in toluene
(5 ml). The yellow-brown solution was chromatographed
on an alumina column (20 cm, activity grade III). Pentane
eluted naphthalene and unreacted 3a; toluene eluted a yel-
low fraction that was evaporated to dryness. The solid so
obtained was purified by crystallization at ꢀ78 ꢁC from a
mixture of THF (10 ml) and pentane (2 ml). Complex 4a
was obtained as yellow crystals (0.3 g, yield 85%). Anal.
Calc. for C24H34Si2Ru: C, 60.12; H, 7.1. Found: C, 59.75;
4-bis(trimethylsilylethynyl)benzene, 4a; arene = 4,40-bis-
(ethynyl)biphenyl, 4b1] (1.0 mmol) and tetrabutylammo-
nium fluoride trihydrate (TBAF) (4 ml, 4.0 mmol) in
THF (5 ml) was stirred at room temperature for 5 h.
The progress of the reaction was checked by removing a
liquid sample of the solution and analysing the residue,
obtained after evaporation of the solvent, by 1H NMR
spectroscopy. The reaction mixture was then poured into
water (15 ml) and extracted with toluene (3 · 10 ml). The
organic extract was dried and the solvent was evaporated
in vacuo. The residue was purified by chromatography on
Panziera, Nicoletta
