Organometallics
ARTICLE
The 31P{1H} NMR analysis revealed that after 22 h at room temperature
only 17% of 4 was converted to 11a.
’ ACKNOWLEDGMENT
This research was supported by the European Research
Council under the FP7 framework (ERC No 246837), by the
Israel Science Foundation, and by the Kimmel Center for
Molecular design. D.M. holds the Israel Matz Professorial Chair
of Organic Chemistry.
Method b. A 90 mL FischerÀPorter tube equipped with a stirring bar
was charged under nitrogen with a THF solution (4.0 mL) of 4 (19.6 mg,
0.037 mmol) and pressurized with hydrogen to 5.5 atm. The reaction
solution was stirred at room temperature. The 31P{1H} NMR analysis of
the reaction solution revealed full consumption of 4 and formation of
compound 11a after 96 h. The reaction was accompanied by a color
change from bright red to dark brown. The solvent was evaporated, and
the residue was extracted with pentane, followed by filtration through a
(0.2 μm) Teflon filter. Evaporation of pentane gave 16.7 mg (90% yield)
of 11a (at 90% purity) as a brown solid.
’ REFERENCES
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Dalton Trans. 2006, 107. (c) Zhang, J.; Leitus, G.; Ben-David, Y.;
Milstein, D. Angew. Chem., Int. Ed. 2006, 45, 1113. (d) Gunanathan,
C.; Ben-David, Y.; Milstein, D. Science 2007, 317, 790.(e) Milstein, D.;
Gunanathan, C.; Gnanprakasam, B.; Balaraman, E.; Zhang, J. US Patent
application pending. (f) Zeng, H.; Guan, Z. J. Am. Chem. Soc. 2011,
133, 1159. (g) Gnanaprakasam, B.; Milstein, D. J. Am. Chem. Soc. 2011,
133, 1682. (h) Gnanaprakasam, B.; Ben-David, Y.; Milstein, D. Adv.
Synth. Catal. 2010, 352, 3169. (i) Balaraman, E.; Gnanaprakasam, B.;
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31P{1H} NMR (C6D6): 83.2 (d, JRhÀP = 165.9 Hz). 1H NMR
(C6D6): 7.06 (t, JHÀH = 7.6 Hz, 1H, Py H4), 6.56 (d, JHÀH = 7.6 Hz,
2H, Py H3,5), 2.92 (vt, JPÀH = 3.0 Hz, 4H, PyÀCH2P), 1.39 (vt, JPÀH
=
6.3 Hz, 36H, PÀt-Bu), À12.82 (vq, J = 20.5 Hz, 1H, RhÀH). 1H{31P}
NMR (C6D6): À12.82 (d, JRhÀH = 19.2 Hz, 1H, RhÀH). 13C{1H}
NMR (C6D6): 162.19 (dvt, JPÀC = 7.0 Hz, JRhÀC = 1.5 Hz, Py C2,6),
129.50 (s, Py C4), 119.31 (vt, JPÀC = 4.8 Hz, Py C3,5), 38.62 (dvt,
JPÀC = 3.1 Hz, JRhÀC = 1.1 Hz, PyÀCH2P), 33.97 (dvt, JPÀC = 5.7 Hz,
JRhÀC = 2.8 Hz, PÀC(CH3)3), 29.96 (vt, JPÀC = 4.7 Hz, PÀC(CH3)3).
Assignment of 13C{1H} NMR signals was confirmed by 13C DEPT and
1
by 13CÀ H HSQC correlation. Anal. Found (calcd for C23H44NP2Rh):
C, 55.41 (55.31); H, 8.74 (8.88).
Computational Methods. All calculations were carried out using
Gaussian09, revision A.02.22 Two members of the M06 family of DFT
functionals23 were used: M06, a meta-hybrid functional containing 27%
HF exchange,24 and M06-L, its local (nonhybrid) variant.25
With these functionals, two basis setÀRECP (relativistic effective
core potential) combinations were used. The first, denoted SDD(d), is
the combination of the HuzinagaÀDunning double-ζ (D95 V) basis
set26 on lighter elements with the StuttgartÀDresden basis setÀRECP
combination27 on transition metals; extra polarization functions (i.e. the
D95(d) basis set) were added to phosphorus. The second, denoted
SDB-cc-pVDZ, combines the Dunning cc-pVDZ basis set28 on the main-
group elements and the Stuttgart-Dresden basis setÀRECP27 on the
transition metals with an added f-type polarization exponent taken as the
geometric average of the two f exponents given in the appendix of ref 29.
In order to improve the efficiency of the calculations, density-fitting
basis sets (DFBS) were employed during the calculation of the Coulomb
interaction. The automatic DFBS generation algorithm as implemented
in Gaussian09 was employed.30
Geometries were optimized using the default pruned (75,302) grid,
while the “ultrafine” (i.e., a pruned (99,590)) grid was used for evaluat-
ing the charges, especially essential for calculations with the M06 family
of functionals.31
Geometry optimizations and frequency calculations were performed
in the gas phase at the M06-L/SDD(d)/DFBS level of theory. The
charges were reevaluated at the M06/SDB-cc-pVDZ level of theory.
This combined level of theory is conventionally denoted as M06/SDB-
cc-pVDZ//M06-L/SDD(d)/DFBS.
(7) Tanaka, R.; Yamashita, M.; Nozaki, K. J. Am. Chem. Soc. 2009,
131, 14168.
’ ASSOCIATED CONTENT
(8) (a) Ben Ari, E.; Leitus, G.; Shimon, L. J. W.; Milstein, D. J. Am.
Chem. Soc. 2006, 128, 15390. (b) Schwartsburd, L.; Iron, M. A.;
Konstantinovski, L.; Diskin-Posner, Y.; Leitus, G.; Shimon, L. J. W.;
Milstein, D. Organometallics 2010, 29, 3817. For CÀH oxidative addition
to the aromatic [(PNP)IrI(COE)]BF4 complex see: (c) Ben-Ari, E.;
Gandelman, M.; Rozenberg, H.; Shimon, L. J. W.; Milstein, D. J. Am.
Chem. Soc. 2003, 125, 4714. (d) Ben-Ari, E.; Cohen, R.; Gandelman, M.;
Shimon, L. J. W.; Martin, J. M. L.; Milstein, D. Organometallics 2006,
25, 3190.
S
Supporting Information. Tables giving Cartesian co-
b
ordinates (XYZ format) of the DFT optimized geometries and
figures giving NMR spectra of the complexes 2, 8, 10, and 11a.
This material is available free of charge via the Internet at http://
pubs.acs.org.
’ AUTHOR INFORMATION
(9) (a) Iron, M. A.; Ben-Ari, E.; Cohen, R.; Milstein, D. Dalton
Trans. 2009, 9433. (b) Zeng, G.; Guo, Y.; Li, S. Inorg. Chem. 2009,
48, 10257.
Corresponding Author
*E-mail: david.milstein@weizmann.ac.il. Fax: 972-8-9346569.
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dx.doi.org/10.1021/om200104b |Organometallics 2011, 30, 2721–2729