Organometallics
Article
with HyPix diffractometer using mirror-monochromated Mo Kα
XANES and EXAFS measurements were carried out at the BL14B2
beamline of the synchrotron SPring-8 in Japan under standard
beamline conditions of BL14B2. The Ir LIII-edge (11.22 keV) XAFS
data were corrected by transmission mode using N2/Ar mixed gas-
filled ionization chambers with the optimized gas ratio and pressure or
by fluorescence mode using 19-element Ge solid-state detector (19-
SSD) with Si (111) double-crystal monochromator. For the energy
calibration of XANES spectra of Ir LIII-edge, iridium metal powder
was used as a reference sample to set the inflection point determined
by the maximum first-derivative of XANES spectra to 11218 eV (see
All manipulations involving air- and moisture-sensitive compounds
were carried out using standard Schlenk techniques under a nitrogen
atmosphere or in a glovebox under argon atmosphere. Dehydrated
hexane, THF, and Et2O were purchased from Kanto Chemical
Company and purified by SPS27 prior to use unless otherwise noted.
The 12-crown-4 used was dried over Na benzophenone ketyl and
distilled under a reduced presser. Other dehydrated solvents were
purchased from Wako and used without further purification. mer-
RhCl3(tht)3 (1Rh) and mer-IrCl3(tht)3 (1Ir) were synthesized
according to the literature.28 All other commercially available reagents
were used as received unless otherwise stated.
thf). 13C NMR (126 MHz, THF-d8, 25 °C): δ 164.8 (Cipso), 144.3,
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126.0, 119.0. Li NMR (194 MHz, THF-d8, −60 °C): δ 0.81 (2Li),
−0.45 (1Li). Anal. Calcd for C48H54O3IrLi3: C, 64.63; H, 6.10.
Found: C, 64.57; H, 5.97. Single crystals of 2Ir suitable for X-ray
crystallography were obtained by recrystallization from THF. Single
crystals of 3Ir suitable for X-ray crystallography were grown by
recrystallization of complex 2Ir from THF and pentane (vapor
diffusion method) in the presence of 12-crown-4 at −35 °C under an
Ar atmosphere.
Reaction of 2Ir with CO2 and CO. In a glovebox, 2Ir (11 mg, 12.5
μmol), mesitylene as an internal standard (5.0 μL), and THF-d8 (0.65
mL) were charged into a NMR tube. After sealing it with a Teflon-
lined screw cap, the NMR tube was brought out from the glovebox.
The NMR tube was degassed by a freeze−thaw cycle (2 times) and
refilled with CO or CO2 gas (1 atm) via the screw cap. The reaction
1
was monitored by H NMR at room temperature.
DFT Calculation and FEFF Fitting Analysis of EXAFS. DFT
calculations were carried out with the M06 functional30 as
implemented in the Gaussian 16 suite of programs.31 Molecular
structures were optimized at M06/Def2-SVP (and associated ECPs
for Rh and Ir) level of theory using the molecular structure of 3Ir
determined by X-ray crystallography as an initial geometry. The
atomic coordinate of anionic part [IrPh6{Li(thf)}2]− extracted from
the above DFT-calculated structure was used for the FEFF fitting.
The FEFF fitting analysis of EXAFS spectra of 2Ir in THF using DFT-
calculated atomic coordinate was carried out by IFEFFIT (revision
1.2.12)32 embedded with Artemis.33
Solvent-Free PhLi.29 In a three-necked flask, phenyl iodide
(24.76 g, 0.121 mol) was dissolved in benzene (40 mL). To this
mixture, n-BuLi (in hexane, 2.67 M, 39.0 mL, 0.104 mol) was slowly
added at room temperature over 60 min. After stirring for 16 h at the
same temperature, the resulting precipitates were collected by
filtration with a glass filter in a glovebox, and the white solid was
washed with an excess amount of hexane for twice. Then, the white
solid was dissolved in Et2O, and upon slow immersion into cooling
bath at −78 °C to obtain PhLi as colorless block crystals. The
supernatant was quickly removed by cannulation. After a second
recrystallization in the same manner, the crystals were dried under
ASSOCIATED CONTENT
* Supporting Information
■
sı
The Supporting Information is available free of charge at
Spectroscopic data, kinetics of 2Rh decomposition, X-ray
crystallographic data, fitting analyses, and theoretical
1
vacuum to give a white solid (9.35 g, 91%). H NMR (500 MHz,
THF-d8, 25 °C): δ 7.93 (d, J = 6.4 Hz, 2H, o-H), 6.87 (t, J = 6.7 Hz,
2H, m-H), 6.77 (t, J = 7.2 Hz, 1H, p-H).
Cartesian coordinates (XYZ)
[Li(thf)n][RhPh6{Li(thf)}2] (2Rh). In a glovebox, PhLi (67.2 mg,
0.800 mmol) was dissolved in THF (1 mL) and slowly added to a
suspension of RhCl3(tht)3 (47.4 mg, 0.100 mmol) in THF (3 mL) at
room temperature. After stirring for 5 min at the same temperature,
an excess amount of hexane (ca. 10 mL) was added to the resulting
mixture. The supernatant was removed by decantation, and the
resulting precipitates were dissolved in benzene (ca. 5 mL). The
resulting mixture was filtered, and the solution was concentrated
under vacuum to afford 2Rh as a beige solid (56.4 mg, 70%). Mp =
Accession Codes
tallographic data for this paper. These data can be obtained
Cambridge Crystallographic Data Centre, 12 Union Road,
Cambridge CB2 1EZ, UK; fax: +44 1223 336033.
1
114 °C (dec.). IR (nujor): 2919, 2855, 1456, 1375 cm−1. H NMR
AUTHOR INFORMATION
Corresponding Authors
(500 MHz, THF-d8, 25 °C): δ 7.82 (d, J = 6.9 Hz, 12H, o-H), 6.55−
6.54 (m, 18H, m- and p-H), 3.63−3.60 (m, thf), 1.79−1.76 (m, thf).
13C NMR (126 MHz, CD3CN, 25 °C): δ 162.3 (d, 1JRh−C = 36.7 Hz,
Cipso), 141.3, 125.5(d, 2JRh−C = 2.3 Hz, Cortho), 120.9, 68.2 (thf), 26.2
■
Takanori Iwasaki − Department of Chemistry and
Biotechnology, Graduate School of Engineering, The
University of Tokyo, Tokyo 113-8656, Japan; orcid.org/
7
(thf). Li NMR (194 MHz, THF-d8, −60 °C): δ 0.76, −0.58. Anal.
Calcd for C48H54O3Li3Rh: C, 71.83; H, 6.78. Found: C, 71.85; H,
6.87. Single crystals of 3Rh suitable for X-ray crystallography were
obtained by recrystallization of 2Rh from THF and pentane (vapor
diffusion method) in the presence of 12-crown-4 at −25 °C under an
Ar atmosphere.
Kyoko Nozaki − Department of Chemistry and Biotechnology,
Graduate School of Engineering, The University of Tokyo,
[Li(thf)n][IrPh6{Li(thf)}2] (2Ir). In a glovebox, PhLi (135.7 mg,
1.61 mmol) was dissolved in THF (2 mL) and slowly added to a
suspension of IrCl3(tht)3 (112.2 mg, 0.209 mmol) in THF (6 mL) at
room temperature. After stirring for 5 min at the same temperature,
an excess amount of hexane (ca. 20 mL) was added to the resulting
mixture. The supernatant was removed by decantation, and the
resulting precipitates were dissolved in benzene (ca. 10 mL). The
resulting mixture was filtered, and the solution was concentrated
under vacuum to afford 2Ir as a white solid (136.1 mg, 76%). Mp =
Authors
Yuko Hirooka − Department of Chemistry and Biotechnology,
Graduate School of Engineering, The University of Tokyo,
Tokyo 113-8656, Japan
Hikaru Takaya − Institute of Chemical Research, Kyoto
University, Kyoto 611-0011, Japan; Department of Photo-
Molecular Science, Institute for Molecular Science, Okazaki,
1
184 °C (dec.). IR (nujor): 2919, 2855, 1456, 1375 cm−1. H NMR
(500 MHz, THF-d8, 25 °C): δ 7.80 (dd, J = 3.1, 1.5 Hz, 12H, o-H),
6.55−6.48 (m, 18H, m- and p-H), 3.62−3.60 (m, thf), 1.79−1.76 (m,
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Organometallics 2021, 40, 2489−2495