2908
R.D. Adams et al. / Journal of Organometallic Chemistry 696 (2011) 2904e2909
IreSn distance, 2.6610(3) Å, found for the similar compound
Ir(CO)3(SnPh3)[P(cyclo-C6H11)]3 [18].
An ORTEP diagram of the molecular structure of 5 is shown in
Fig. 4. Compound 5 contains six ligands: two SnPh3, one PPh3, two
CO ligands and one hydride arranged in an octahedral-like
geometry. The two SnPh3 ligands are trans to one another, but
are displaced toward the hydride ligand, Sn(1)eIr(1)e
Sn(2) ¼ 153.76(2)ꢁ. The Ir - Sn distances, Ir(1) - Sn(1) ¼ 2.6649(5)
Å, Ir(1) - Sn(2) ¼ 2.6744(6) Å are similar to that in 4. The hydride
ligand was located and refined in the analysis and lies trans to the
PPh3 ligand,
d
¼ ꢀ10.97 (2JP-H ¼ 89.73 Hz). The refined Ir(1)eH(1)
distance 1.27(5) Å is a little shorter than expected, but the stan-
dard deviation is large due to the low scattering power of
hydrogen relative to that of iridium. The CO ligands lie trans to one
another, C(1)eIr(1)eC(2) ¼ 174.9(3)ꢁ. Compound 4 can be con-
verted to 5 in 78% yield by a reaction with HSnPh3 that is
accompanied with a loss of CO.
Scheme 1.
Sn(1) ¼ 150.68(4)ꢁ. This distortion is probably of a steric origin. The
IreSn bond distance, Ir(1) - Sn(1) ¼ 2.6455(6) Å, is slightly longer
than the IreSn distance, 2.6216(5) Å, that we observed in the less-
crowded 5-coordinate complex Ir(COD)(CO)2SnPh3, 6 [15]. The
hydride ligand was located in a difference Fourier synthesis and
refined by using the restraint, IreH ¼ 1.80 Å. The hydride exhibits
the characteristic high-field resonance shift in the 1H NMR spec-
5. Summary
The reactions and products reported here are shown in Scheme 1.
If was found that the reaction of 1 with HSnPh3 yields the oxidative
addition product 2 which has a cis stereochemistry of the SnPh3 and
H ligands on the iridium atom. Compound 2 reacts with a second
equivalent of HSnPh3 by a Cl for H exchange to yield the product
3 that contains two cis-related hydride ligands.
Under an atmosphere of CO, compound 1 reacts with HSnPh3 to
replace the Cl ligand with SnPh3 and one of the PPh3 ligands with
a CO ligand and also adds a second equivalent of CO to yield the
5-coordinate 18 electron iridium (I) complex 4. The mechanism of
the formation of 4 was not established in this work. Compound 4
reacts with HSnPh3 by loss of CO and oxidative addition of the Sn-H
bond to yield the 6-coordinate 18 electron iridium (III) complex 5
that contains two trans-positioned SnPh3 ligands.
trum,
d
¼ ꢀ8.12 with suitable couplings to the cis and trans related
2
phosphine ligands, 2JP1ꢀHcis ¼ 14.71 Hz, JP2ꢀHtrans ¼ 146.15 Hz.
When compound 1 was allowed to react with 5 equivalents of
HSnPh3, the new compound H2Ir(CO)(SnPh3)(PPh3)2,
3 was
obtained in 37% yield. Compound 3 was also obtained in 51% yield
from a reaction of 2 with HSnPh3 at room temperature. An ORTEP
diagram of the molecular structure of 3 is shown in Fig. 2.
Compound 3 differs from 2 in that the Cl ligand has been replaced
by a hydride ligand. We and others have shown that HSnPh3 will
react with certain metal halide complexes including those of
iridium to substitute the halide ligand with a SnPh3 ligand [15]. Like
2, compound 3 also has a distorted octahedral arrangement of its
six ligands. As in 2, the two PPh3 ligands are cis-related, P(2)eIr(1)e
P(1) ¼ 104.99(4)ꢁ. There are two cis-related hydride ligands with
appropriate couplings to each other and to the phosphine ligands,
Acknowledgements
This research was supported by the National Science Foundation
under Grant No. CHE-0743190. We thank the USC NanoCenter for
partial support of this work.
2
2
d
¼ ꢀ11.42 (ddd, hydride, JP2ꢀH1 ¼ 16.40 Hz, JP1ꢀH1 ¼ 99.98 Hz,
1JH2ꢀH1 ¼4.40 Hz) and ꢀ10.430 (ddd, hydride, 2JPꢀH1 ¼19.20 Hz and
1
14.80Hz, JH1ꢀH2 ¼ 4.80 Hz). The SnPh3 ligand lies cis to the two
Appendix A. Supplementary Material
hydride ligands cis to one PPh3 ligand, P(1)eIr(1)e
Sn(1) ¼ 100.57(3)ꢁ, and approximately trans to the other, P(2)e
Ir(1)eSn(1) ¼ 147.52(3)ꢁ. The IreSn bond distance is slightly
shorter than that in 2, Ir(1) - Sn(1) ¼ 2.6259(3) Å. The IR spectrum
CCDC 812194e812197 contain the supplementary crystallo-
graphic data for compounds 2e5. These data can be obtained free of
charge from the Cambridge Crystallographic Data Centre via www.
exhibits two absorptions in the CO stretching region, 2071 cmꢀ1
,
1965 cmꢀ1. The absorption at 2071 cmꢀ1 is due to the hydride
ligands. This was confirmed by synthesizing the dideuteride
References
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.
The difference in the position of the CO absorption between 3 and
3-d2 is due to the effects of coupling of the hydride vibration to the
CO vibration in 3 [16].
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