A ferrocenyldiphosphene-platinum complex: Structural features and theoretical calculations

Article abstract of DOI:10.1021/om800315q

The ligand exchange reaction of (E)-TbtP=PFc (Tbt - 2,4,6- tris[bis(trimethylsilyl)methyl]phenyl, Fc = ferrocenyl) and ethylenebis(triphenylphosphine)platinum(0) resulted in the formation of the corresponding η²-diphosphene-platinum complex in 82% yield. The molecular structure of the platinum complex was confirmed by spectroscopic and X-ray cristallographic analyses.

Full text of DOI:10.1021/om800315q

Organometallics 2008, 27, 4265–4268
4265
Notes
A Ferrocenyldiphosphene-Platinum Complex: Structural Features
and Theoretical Calculations
Noriyoshi Nagahora,†,‡ Takahiro Sasamori,† and Norihiro Tokitoh*,†
Institute for Chemical Research and Institute of Sustainability Science, Kyoto UniVersity, Gokasho, Uji,
Kyoto 611-0011, Japan
ReceiVed April 8, 2008
Chart 1
Summary: The ligand exchange reaction of (E)-TbtPdPFc (Tbt
) 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl, Fc ) ferrocenyl)
and ethylenebis(triphenylphosphine)platinum(0) resulted in the
formation of the corresponding η2-diphosphene-platinum com-
plex in 82% yield. The molecular structure of the platinum
complex was confirmed by spectroscopic and X-ray crystal-
lographic analyses.
Sincethefirstsynthesisofastablediphosphene(Mes*PdPMes*;
Mes* ) 2,4,6-tri-tert-butylphenyl) by taking advantage of
kinetic stabilization,1 an impressive advance has been made in
the chemistry of double-bond compounds between heavier group
15 elements (dipnictenes).2 We also succeeded in the synthesis
of novel doubly bonded systems between heavier group 15
elements, diphosphene (RPdPR), distibene (RSbdSbR), dibis-
muthene (RBidBiR), phosphabismuthene (RPdBiR), and
stibabismuthene (RSbdBiR), by using the efficient steric
protection groups 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl
(Tbt) and 2,6-bis[bis(trimethylsilyl)methyl]-4-[tris(trimethylsi-
lyl)methyl]phenyl (Bbt) (Chart 1).3 Furthermore, we extended
this chemistry to the construction of novel d-π systems
containing a diphosphene unit and succeeded in the synthesis
of the stable (E)-ferrocenyldiphosphene3h and 1,1′-bis[(E)-diphos-
phenyl]ferrocenes.3k,n
complexes,4-8 the detailed structural features and bonding
properties of the diphosphene-platinum complexes, especially
whether they exhibit three-membered-ring or π-complex char-
acter as shown in Figure 1, have not been revealed in the
previous reports.
During the course of our research on the novel d-π electron
systems ferrocenyldiphosphenes, the platinum complex of Tbt-
substituted ferrocenyldiphosphene was obtained and structurally
characterized. In this note, we report the reaction of ferroce-
nyldiphosphene 1b, (E)-TbtPdPFc (Fc ) ferrocenyl), with a
(3) (a) Tokitoh, N.; Arai, Y.; Okazaki, R.; Nagase, S. Science 1997,
277, 78–80. (b) Tokitoh, N.; Arai, Y.; Sasamori, T.; Okazaki, R.; Nagase,
S.; Uekusa, H.; Ohashi, Y. J. Am. Chem. Soc. 1998, 120, 433–434. (c)
Sasamori, T.; Takeda, N.; Tokitoh, N. Chem. Commun. 2000, 1353–1354.
(d) Sasamori, T.; Arai, Y.; Takeda, N.; Okazaki, R.; Furukawa, Y.; Kimura,
M.; Nagase, S.; Tokitoh, N. Bull. Chem. Soc. Jpn. 2002, 75, 661–675. (e)
Sasamori, T.; Takeda, N.; Fujio, M.; Kimura, M.; Nagase, S.; Tokitoh, N.
Angew. Chem., Int. Ed. 2002, 41, 139–141. (f) Sasamori, T.; Takeda, N.;
Tokitoh, N. J. Phys. Org. Chem. 2003, 16, 450–462. (g) Sasamori, T.;
Mieda, E.; Takeda, N.; Tokitoh, N. Chem. Lett. 2004, 33, 104–105. (h)
Nagahora, N.; Sasamori, T.; Takeda, N.; Tokitoh, N. Chem. Eur. J. 2004,
10, 6146–6451. (i) Sasamori, T.; Mieda, E.; Nagahora, N.; Takeda, N.;
Takagi, N.; Nagase, S.; Tokitoh, N. Chem. Lett. 2005, 34, 166–167. (j)
Sasamori, T.; Mieda, E.; Takeda, N.; Tokitoh, N. Angew. Chem., Int. Ed.
2005, 44, 3717–3720. (k) Nagahora, N.; Sasamori, T.; Tokitoh, N. Chem.
Lett. 2006, 35, 220–221. (l) Sasamori, T.; Mieda, E.; Nagahora, N.; Sato,
K.; Shiomi, D.; Takui, T.; Hosoi, Y.; Furukawa, Y.; Takagi, N.; Nagase,
S.; Tokitoh, N. J. Am. Chem. Soc. 2006, 128, 12582–12588. (m) Sasamori,
T.; Tsurusaki, A.; Nagahora, N.; Matsuda, K.; Kanemitsu, Y.; Watanabe,
Y.; Furukawa, Y.; Tokitoh, N. Chem. Lett. 2006, 35, 1382–1383. (n)
Nagahora, N.; Sasamori, T.; Watanabe, Y.; Furukawa, Y.; Tokitoh, N. Bull.
Chem. Soc. Jpn. 2007, 80, 1884–1900. (o) Sasamori, T.; Mieda, E.; Tokitoh,
N. Bull. Chem. Soc. Jpn. 2007, 80, 2425–2435. (p) Nagahora, N.; Sasamori,
T.; Tokitoh, N. Heteroat. Chem. 2008, 19, 443–449.
Whereas the isolable diphosphenes are prevented from
dimerization by steric protection groups, these stabilized diphos-
phenes are known to show considerable reactivity:2a,d e.g.,
oxidation (diatomic oxygen), chalcogenation (elemental sulfur
and selenium), halogenation (chlorine, bromine, and iodine),
cycloaddition (dienes), and metalation (group 6, 8, 10, and 11
elements) reactions. It is particularly attractive for chemists to
elucidate the properties of diphosphene-platinum complexes
from the viewpoint of not only the reactivity of dipnictene
species but also the development of promising candidates for
new homogeneous catalysts. Although a few reports have been
known so far for the formation of diphosphene-platinum
* To whom correspondence should be addressed. Tel: +81-774-38-3200.
Fax: +81-774-38-3209. E-mail: tokitoh@boc.kuicr.kyoto-u.ac.jp.
† Institute for Chemical Research.
(4) Chatt, J.; Hitchcock, P. B.; Pidcock, A.; Warrens, C. P.; Dixon, K.
J. Chem. Soc., Dalton Trans. 1984, 2237–2244.
(5) Spang, C.; Edelmann, F. T.; Noltemeyer, M.; Roesky, H. W. Chem.
Ber. 1989, 122, 1247–1254.
(6) Jutzi, P.; Meyer, U.; Opiela, S.; Neumann, B.; Stammler, H.-G. J.
Organomet. Chem. 1992, 439, 279–301.
(7) Weber, L.; Schumann, I.; Stammler, H.-G.; Neumann, B. J.
Organomet. Chem. 1993, 443, 175–183.
(8) Pietsching, R.; Niecke, E. Organometallics 1996, 15, 891–893.
‡ Institute of Sustainability Science.
(1) Yoshifuji, M.; Shima, I.; Inamoto, N.; Hirotsu, K.; Higuchi, T. J. Am.
Chem. Soc. 1981, 103, 4587–4589.
(2) For reviews, see: (a) Weber, L. Chem. ReV. 1992, 92, 1839–1906.
(b) Power, P. P. Chem. ReV. 1999, 99, 3463–3503. (c) Tokitoh, N. J.
Organomet. Chem. 2000, 611, 217–227. (d) Sasamori, T.; Tokitoh, N.
Dalton Trans. 2008, 1395–1408.
10.1021/om800315q CCC: $40.75
2008 American Chemical Society
Publication on Web 08/02/2008

4266 Organometallics, Vol. 27, No. 16, 2008
Notes
Scheme 1. Reactions of Diphosphenes 1a,b with
Platinum(0) Complexa
a
Figure 1. Resonance structures of 2b.
platinum(0) complex leading to the formation of the corre-
a
Reagents and conditions: (i) [Pt(C2H4)(PPh3)2] (5.0 equiv)/C6D6,
sponding
platinum-diphosphene
complex
[Pt(η2-
100 °C, 48 h, in a sealed tube (for 1a); (ii) [Pt(C2H4)(PPh3)2] (1.6 equiv)/
C6D6, room temperature, 2 h (for 1b).
TbtPdPFc)(PPh3)2] and its structural properties from the
standpoints of the NMR spectra and X-ray crystallographic
analysis together with theoretical calculations using a model
complex.
Table 1. 31P NMR Data of [Pt(η2-R1PdPR2)(PPh3)2]
Results and Discussion
At first, we attempted the synthesis of the platinum(0)
complex of trans-TbtPdPTbt (1a), which can be easily prepared
by the reductive coupling reaction of TbtPCl2 with magnesium
quantitatively,3f by the reaction of 1a with [Pt(C2H4)(PPh3)2]
(5.0 equiv). As a result, 1a was found to undergo no ligand
exchange reaction, even under severe conditions (at 100 °C for
48 h in benzene-d6 in a sealed tube), probably due to the steric
reasons. In contrast to the case for 1a, the treatment of
diphosphene 1b bearing a ferrocenyl group, which is less
hindered than the Tbt group, with [Pt(C2H4)(PPh3)2] (1.6 equiv)
in benzene-d6 at room temperature for 2 h afforded diphos-
phene-platinum(0) complex 2b as orange crystals in 82%
isolated yield (Scheme 1). Complex 2b was found to be stable
enough to be handled in air and even on silica gel. The 31P
NMR spectrum of 2b in benzene-d6 showed an ABMX spin
system at 28.3, 27.9, 6.20, and -33.1 ppm, the first two signals
of which were assignable to the phosphorus atoms of the two
triphenylphosphine ligands of 2b compared with those of
platinum complexes 3-5 (Table 1).4,5,8 The third signal (6.20
ppm) appeared slightly upfield as compared with those for
platinum complexes 3 and 5.4,8 The last signal (-33.1 ppm)
was found to be close to those of the ferrocenyl-substituted
phosphorus atoms in diphosphene-platinum complexes 4 and
δP (ppm) |1JPP|(Hz)
2JPP(Hz)
1JPtP (Hz) ref
R1 ) Tbt,
P1
6.20 397 (P1-P2) 60.0 (P1-P3) 266 (P1)
this
work
R2 ) Fc (2b)a
P2 -33.1
38.0 (P2-P4) 143 (P2)
8.0 (P3-P4) 3420 (P3)
3400 (P4)
P3
P4
27.9
28.3
R1 ) R2
Ph (3)b
)
)
P1
P3
P1
P3
P1
18.1
28.3
-8.2
27.6
25.5
60 (trans)
4 (cis)
288 (P1)
4
5
8
3353 (P3)
R1 ) R2
Fc (4)a
31.8 (trans) 279.9 (P1)
3339.8 (P3)
2.6 (cis)
R1 ) Mes*,
R2 ) Fc (5)d
424 (P1-P2) 52.5 (P1-P3) c
P2 -16.1
36.0 (P2-P4)
4.0 (P1-P4)
3.0 (P2-P3)
8.0 (P3-P4)
P3
P4
24.8
26.4
2
4
2
3
a In benzene-d6. Values of JP P and JP P were estimated to be
1
2
under 5.0 Hz. b In benzene. c The value was not reported. d In toluene.
X-ray crystallographic analysis, the structural features of
platinum complexes have not been fully investigated until now.
The molecular structure of 2b was determined by X-ray
crystallographic analysis (Figure 2), and the selected structural
parameters are summarized in Table 2. It was found that the
Tbt and ferrocenyl groups of 2b are oriented in a trans
conformation with a torsion angle of 156.6(2)°. The Pt-P(PPh3)
bond lengths for 2b (2.2841(12) and 2.3025(12) Å) lie in the
range of those for platinum complexes 6-8 (2.276-2.349
Å).7,10,11 The Pt-P(PdP) bond lengths for 2b were 2.3838(12)
Å (Tbt group) and 2.3916(12) Å (Fc group), which are similar
to those for complexes 6-8 (2.319-2.400 Å).7,10,11 Accord-
ingly, the Pt-P(PPh3) bond lengths were shorter than Pt-P(PdP),
as in the case of the reported Pt complexes 7 and 8,7,11
suggesting that the p character of the Pt-P(PdP) bond of 2b
is higher than those of the Pt-P(PPh3) bonds. The P-P bond
length of 2b (2.1549(17) Å), being within the range of those
for the reported complexes 6-8 (2.140-2.156 Å),7,10,11 is
shorter than typical P-P single-bond lengths (ca. 2.19-2.24
Å)9 and longer than the typical PdP double-bond lengths of
the reported (E)-diaryldiphosphenes (1.985-2.051 Å).2a,d This
structural feature can be explained by the π back-donation from
d orbitals of the Pt atom into the π* orbital of the PdP unit in
2b.
1
5.5,8 While the JPP value of 2b (397 Hz) lies in the range of
those for the reported diphosphene-platinum complexes
(275-439 Hz),4-8 it is considerably smaller than that of the
corresponding diphosphene 1b (546 Hz)3h and is somewhat
larger than those for the reported diphosphanes (152-250 Hz),9
showing that the phosphorus-phosphorus bond of 2b features
almost intermediate character between double and single bonds
1
in solution. Interestingly, two of the JPtP values of 2b, 266
(PTbt) and 143 Hz (PFc), are far different in magnitude from
the other two 1JPtP values, 3420 and 3400 Hz (PPh3), indicating
that the P-Pt bonds in 2b should have p orbital character higher
than that of the coordination bonds of the PPh3 ligands.
Although there have been three reports on the crystal
structures of [Pt(η2-R1PdPR2)(PPh3)2] (R1, R2: C6F5, C6F5 (6);10
EtMe4CpFe(CO)2, Mes* (7);7 t-Bu2P, t-Bu2P (8)11) revealed by
(9) (a) Schumann, H.; Fischer, R. J. Organomet. Chem. 1975, 88, C13–
C16. (b) van der Sluis, M.; Klootwijk, A.; Wit, J. B. M.; Bickelhaupt, F.;
Veldman, N.; Spek, A. L.; Jolly, P. W. J. Organomet. Chem. 1997, 529,
107–119. (c) Dodds, D. L.; Haddow, M. F.; Orpen, A. G.; Pringle, P. G.;
Woodward, G. Organometallics 2006, 25, 5937–5945.
(10) Elmes, P. S.; Scudder, M. L.; West, B. O. J. Organomet. Chem.
1976, 122, 281–288.
(11) Krautscheid, H.; Matern, E.; Fritz, G.; Pikies, J. Z. Anorg. Allg.
Chem. 2000, 626, 253–257.

Notes
Organometallics, Vol. 27, No. 16, 2008 4267
showed that the P-P bond in 2c consisted of the two σPP and
πPP bonds with high p character (ca. 86% and 96% p character,
respectively), as in the case of (E)-DmpPdPFc (1c) (σPP and
πPP should have ca. 84% and 99% p character, respectively),
whereas no covalent Pt-P bond for 2c was found in the
calculations (Table S6). Although the occupancy of the π*PP
orbital for 1c was ca. 0.10, that for 2c was computed as 0.63.
Moreover, an NBO analysis of 2c based on second-order
perturbation theory exhibited two effective donor-acceptor
interactions: that is, those from the πPP bond into the unoccupied
6s orbital of the Pt atom and from the occupied 5d orbital of
the Pt atom into the empty π*PP bond (Table S7). Thus, it can
be concluded that the bonding property of the Pt-P-P three-
membered ring system in 2c should be predominantly a “π
complex”, as shown in Figure 1.12
In summary, we found the high reactivity of ferrocenyl-
diphosphene 1b stabilized by a Tbt group toward the platinum(0)
complex, which is in sharp contrast to that of the overcrowded
diphosphene 1a bearing two Tbt groups. The molecular structure
of the resulting Pt(0) complex 2b was characterized by its NMR
spectra, and the crystalline structure of 2b was established by
X-ray crystallographic analysis. Taking into consideration these
experimental results together with the theoretical calculations
of the model complex, it can be concluded that 2b exhibits a π
complex character with the Pt atom coordinated by the PdP
moiety in an η2 fashion. These results are the first example of
a detailed elucidation for the structural properties of the
diphosphene-platinum(0) complex both in solution and in the
solid state.
Figure 2. Molecular structure of the major disordered moiety of
[Pt(η2-TbtPdPFc)(PPh3)2] · 0.5C6H14. Displacement ellipsoids were
drawn at the 50% probability level. The phenyl groups of
triphenylphosphines, n-hexane, and hydrogen atoms were omitted
for clarity.
Table 2. Selected Structural Parameters of
[Pt(η2-TbtPdPFc)(PPh3)2] · 0.5C6H14
Bond Lengths (Å)
Pt(1)-P(1)
Pt(1)-P(2)
Pt(1)-P(3)
Pt(1)-P(4)
2.3838(12)
2.3916(12)
2.2841(12)
2.3025(12)
P(1)-P(2)
P(1)-C(1)
P(2)-C(28)
2.1549(17)
1.867(5)
1.839(5)
Bond Angles (deg)
P(1)-Pt(1)-P(2)
Pt(1)-P(1)-P(2)
Pt(1)-P(2)-P(1)
P(3)-Pt(1)-P(4)
53.65(4)
63.36(5)
62.99(5)
104.01(4)
P(1)-Pt(1)-P(4)
P(2)-Pt(1)-P(3)
C(1)-P(1)-P(2)
C(28)-P(2)-P(1)
99.62(4)
100.47(4)
112.13(15)
99.68(16)
Experimental Section
General Procedures. All reactions were carried out under an
argon atmosphere or in a degassed and sealed tube, unless otherwise
noted. All solvents were purified by standard methods and then
dried by using an Ultimate Solvent System (Glass Contour Co.).13
Benzene-d6 for the NMR spectroscopy was dried by using a
potassium mirror prior to use. Preparative thin-layer chromatography
(PTLC) and column chromatography were performed with Merck
Kieselgel 60 PF254. Preparative gel permeation liquid chromatog-
raphy (GPLC) was performed on an LC-918 equipped with JAI-
gel 1H and 2H columns (Japan Analytical Industry Co., Ltd.) with
Torsion Angle (deg)
C(1)-P(1)-P(2)-C(28)
156.6(2)
The P(2)-P(1)-C(1) bond angle of 112.13(15)° for 2b,
which is larger than that of diphosphene 1b (103.15(12)°), is
similar to those (121.4(3) and 111.3(6)°) of the reported
complexes 6 and 7, bearing C6F5 and Mes* groups, respectively.
The sum of the bond angles around the platinum atom of 2b
was found to be 370.26°, indicating that the platinum atom of
2b slightly deviates from a square-planar geometry as compared
with those of the reported complexes 6 (363.2°)10 and 7
(360.0°),11 probably due to the severe steric congestion between
the Tbt and the triphenylphosphine ligands (Figures S1 and S2
in the Supporting Information). Complex 2b exhibits a
C(28)-P(2)-P(1) angle of 99.68(16)°, which is slightly nar-
rowed as compared with that of diphosphene 1b (101.64(16)°).
The bond angle of 2b is the smallest in those of complexes
6-8 (102.0(6)-121.4(3)°),7,10,11 indicating that the P(2) atom
should preserve its original valence-electron configuration,
(3n)2(3p)3, as well as that of diphosphene 1b. Consequently,
these results indicate that the PdP moiety of 2b should be
formed by high p-character orbitals, and it should be noted that
2b has a π-complex structure in the solid state as well as in
solution (Figure 1).
1
toluene as an eluent. H NMR (300 MHz) spectra were measured
in C6D6 with a JEOL AL-300 spectrometer using C6HD5 (δ 7.15
ppm) as an internal standard. 31P NMR (120 MHz) and 195Pt NMR
(85 MHz) spectra were measured in C6D6 with JEOL AL-300 and
AL-400 spectrometers using 85% H3PO4 in water (δ 0 ppm) and
Na2PtCl6 in water (δ 0 ppm) as external standards, respectively.
High-resolution mass spectral data were obtained on a JEOL SX-
270 mass spectrometer. All melting points were determined on a
Yanaco micro melting point apparatus and are uncorrected.
Elemental analyses were performed by the Microanalytical Labora-
tory of the Institute for Chemical Research, Kyoto University.
Ethylenebis(triphenylphosphine)platinum(0) was purchased from
Aldrich Co., Ltd., and purified by recrystallization from n-hexane
before use. trans-TbtPdPTbt (1a)3f and (E)-TbtPdPFc (1b)3h were
prepared according to the procedures reported in the literature.
Reaction
of
(E)-TbtPdPFc
(1b)
with
Ethylenebis(triphenylphosphine)platinum(0). A benzene-d6 solu-
tion (0.7 mL) of 1b (36.9 mg, 46.2 µmol) and [Pt(C2H4)(PPh3)2]
In order to elucidate the bonding character between the PdP
unit and the Pt atom as the resonance structures shown in Figure
1, we carried out theoretical calculations for [Pt(η2-
DmpPdPFc)(PH3)2] (Dmp ) 2,6-dimethylphenyl) as a model
molecule. In the structural optimization of the model molecule
using the B3LYP method, one local minimum (2c) was found
with geometries similar to the crystalline structure of 2b (Table
S5 in the Supporting Information). NBO calculations for 2c
(12) In theoretical calculations for a diaryldiphosphene-platinum
complex such as [Pt(η2-DmpPdPDmp)(PH3)2], it has also been confirmed
that bonding properties of the Pt-P-P three-membered-ring framework
should be those of a π-complex character. The results of the theoretical
calculations are in the Supporting Information.
(13) Pangborn, A. B.; Giardello, M. A.; Grubbs, R. H.; Rosen, R. K.;
Timmers, F. J. Organometallics 1996, 15, 1518–1520.

4268 Organometallics, Vol. 27, No. 16, 2008
Notes
(55.0 mg, 73.6 µmol) was degassed and sealed in an NMR tube.
When the mixture was allowed to stand at room temperature for
2 h, the 31P NMR signals for 1b completely disappeared. Separation
of the mixture by GPLC and PTLC (with n-hexane as eluent)
afforded platinum complex 2b (57.5 mg, 37.8 µmol, 82%) as orange
crystals. 2b: mp 189 °C dec. 1H NMR (300 MHz, C6D6, 45 °C): δ
-0.12 (s, 9H, Si(CH3)3), 0.33 (s, 18H, Si(CH3)3), 0.41 (s, 18H,
Si(CH3)3), 0.62 (s, 9H, Si(CH3)3), 1.38 (s, 1H, CH), 1.60 (s, 1H,
CH), 2.98 (brs, 1H, R-C5H4), 3.54 (br s, 1H, CH), 4.05 (br s, 1H,
ꢀ-C5H4), 4.30 (s, 5H, C5H5), 4.35 (br s, 1H, ꢀ-C5H4), 4.98 (br s,
1H, R-C5H4), 6.82-7.01 (m, 22H, Ar H), 7.28 (m, 10H, Ar H).
31P NMR (120 MHz, C6D6, 25 °C): δ 28.3 (br dd, 2JPP ) 38.0, 8.0
with density functional theory at the B3LYP18 level. Geometries
of (E)-DmpPdPFc (1c) and [Pt(η2-DmpPdPFc)(PH3)2] (2c) were
optimized using the 6-31G(d) basis set for C and H, 6-311+G(2d,p)
for P, and lanl2dz19 for Fe and Pt in the Gaussian 03W. It was
confirmed by frequency calculations that the optimized structures
of 1c and 2c have minimum energies. Theoretically optimized
coordinates of 1c and 2c are shown in Tables S3 and S4 (Supporting
Information), respectively. NBO analysis20 of 1c and 2c was
performed with the LACV3P* basis set (EPC for Fe and Pt and
6-311G* for all other atoms) by using the NBO 5.0 program21 in
Jaguar 7.0; the results are summarized in Tables S6 and S7.
1
2
Acknowledgment. This work was partially supported by
Grants-in-AidforCreativeScientificResearch(No.17GS0207),
Science Research on Priority Areas (No. 19027024, “Synergy
of Elements”), Young Scientist (B) (No. 18750030), the 21st
Century COE Program on Kyoto University Alliance for
Chemistry (B14), and the Global COE Program (B09,
“Integrated Material Science”) from the Ministry of Educa-
tion, Culture, Sports, Science and Technology of Japan. N.N.
is grateful for support from the Integrated Research System
for Sustainability Science (IR3S), in particular from the
Kyoto Sustainability Initiative (KSI) and the Institute of
Sustainability Science (ISS), financed by the Japan Science
and Technology Agency (JST). N.N. is also grateful for
financial support from the Kinki Invention Center.
Hz with satellite signals of JPtP ) 3400 Hz), 27.9 (br dd, JPP
)
1
60.0, 8.0 Hz with satellite signals of JPtP ) 3420 Hz), 6.2 (dd,
2
1
1JPP ) -397 Hz, JPP ) 60.0 Hz with satellite signals of JPtP
)
266 Hz), -33.1 (dd, 1JPP ) -397 Hz, 2JPP ) 38.0 Hz with satellite
signals of 1JPtP ) 143 Hz). 195Pt NMR (85 MHz, C6D6, 25 °C): δ
-5245 (m). HRMS (FAB): m/z found 1518.4301 ([M + H]+), calcd
for C73H98FeP4PtSi6 1518.4310. Anal. Calcd for C73H98FeP4PtSi6:
C, 57.73; H, 6.50. Found: C, 57.98; H, 6.75. Satisfactory 13C NMR
data for 2b could not be obtained, due to its low solubility in
common organic solvents.
X-ray
Crystallographic
Analysis
of
[Pt(η2-TbtPdPFc)(PPh3)2] · 0.5C6H14. Single crystals of 2b were
obtained by slow recrystallization from its chloroform/n-hexane
solution at room temperature. The intensity data were collected on
a Rigaku Mercury CCD diffractometer with graphite-monochro-
mated Mo KR radiation (λ ) 0.710 70 Å). The structure was solved
by direct methods (SHELXS-97)14 and refined by full-matrix least-
squares procedures on F2 for all reflections (SHELXL-97).15 All
non-hydrogen atoms were refined anisotropically, except for the
minor part of the n-hexane, which these atoms were refined
isotropically. All hydrogen atoms were placed using AFIX instruc-
tions. The CH(SiMe3)2 group at the para position of the Tbt group
of 2b was disordered, and the occupancies were refined to be in
the ratio 0.74:0.26. The disordered CH(SiMe3)2 groups of 2b were
restrained using SADI instructions. The methyl and methylene
groups of the n-hexane molecule were disordered, and the occupan-
cies were refined to be in the ratio 0.74:0.26. The disordered methyl
and methylene groups were restrained by using DFIX and SADI
instructions. Selected structural parameters and crystal data of
2b · 0.5C6H14 are given in Tables 2 and S2 (Supporting Information),
respectively. Crystallographic data have been deposited at the
CCDC, 12 Union Road, Cambridge CB2 1EZ, U.K., and copies
can be obtained on request, free of charge, by quoting the
publication citation and the deposition number 651582.
Supporting Information Available: Tables and figures giving
NMR data of the reported η2-diphosphene-platinum complexes
(Table S1), crystallographic data of 2b · 0.5C6H14 (Table S2),
theoretically optimized coordinates of 1c and 2c (Tables S3 and
S4, respectively), selected structural parameters of 2b · 0.5C6H14,
2c, and 1b (Table S5), summarized results of NBO calculations of
1c and 2c (Table S6), NBO occupancies and donor-acceptor
stabilization energies for 2c (Table S7), and molecular structures
of 2b · 0.5C6H14 (Figures S1 and S2) and a CIF file giving X-ray
crystallographic data for 2b · 0.5C6H14. This material is available
free of charge via the Internet at http://pubs.acs.org.
OM800315Q
(17) Jaguar 7.0; Schro¨dinger, LLC, New York, 2007.
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Hay, R. J.; Wadt, W. R. J. Chem. Phys. 1985, 82, 284–298. (c) Hay, R. J.;
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(21) Glendening, E. D., NBO 5.0; Theoretical Chemistry Institute,
University of Wisconsin, Madison, WI, 2001.
Theoretical Calculations. All theoretical calculations were
carried out using the Gaussian 03W16 and Jaguar 7.017 packages
(14) Sheldrick, G. M. Acta Crystallogr., Sect. A 1990, 46, 467–473.
(15) Sheldrick, G. M. SHELXL-97, Program for the Refinement of
Crystal Structures; University of Go¨ttingen, Go¨ttingen, Germany, 1997.
(16) Frisch, M. J., Gaussian 03, Revision E.01; Gaussian, Inc., Pittsburgh,
PA, 2003.