Synthetic and structural studies on the transition-metal fullerene complexes (η2-C60)M[(η5-Ph 2PC5H4)2Ru]

Article abstract of DOI:10.1021/om049667a

A toluene solution of C₆₀ reacted with an equimolar quantity of M(dba)₂ (M = Pd, Pt; dba = dibenzylideneacetone) and (η ⁵-Ph₂PC₅H₄)₂Ru or with M(PPh₃)₄ and (η⁵Pb₂PC ₅H₄)₂Ru at room temperature to give the dinuclear transition-metal fullerene complexes (η²-C ₆₀)M[(η⁵Ph₂PC₅H ₄)₂Ru] (1, M = Pd; 2, M = Pt), whereas the o-dichlorobenzene solution of C₆₀ reacted with an equimolar amount of M(dba)₂ and [(η⁵-Ph₂PC₅H ₄)₂Co]₊(PF₆)_- or with M(PPh₃)₄ and [(η⁵-Ph₂PC ₅H₄)₂Co]⁺(PF₆) ^- under similar conditions to afford the dinuclear transition-metal fullerene complexes (η²-C₆₀)M[(η ⁵-Ph₂PC₅H₄)₂Co] ⁺(PF₆)^- (3, M = Pd; 4, M = Pt). In addition, the related complex {[η⁵-Ph₂P(O)C₆H ₄]₂Co}⁺(PF₆)^- (5) was prepared by oxidation of [(η⁵-Ph₂-PC₅H ₄)₂Co]⁺(PF₆)^- with an excess amount of aqueous peracetic acid in acetone at room temperature. While 1-4 are the first examples of neutral and cationic dinuclear M/Ru and M/Co (M = Pd, Pt) fullerene complexes, 5 is the first organocobalt Cp complex containing a phosphoryl substituent. All products 1-5 have been fully characterized by elemental analysis, spectroscopy, and X-ray crystal diffraction techniques and, for 1 and 2, by cyclic voltammetry.

Full text of DOI:10.1021/om049667a

4192
Organometallics 2004, 23, 4192-4198
Syn th etic a n d Str u ctu r a l Stu d ies on th e
Tr a n sition -Meta l F u ller en e Com p lexes
(η2-C60)M[(η5-P h 2P C5H4)2Ru ] a n d
(η2-C60)M[(η5-P h 2P C5H4)2Co]+(P F 6)- (M ) P d , P t) a n d th e
Rela ted Com p ou n d {[η5-P h 2P (O)C5H4]2Co}+(P F 6)-
Li-Cheng Song,* Guang-Ao Yu, Fu-Hai Su, and Qing-Mei Hu
Department of Chemistry, State Key Laboratory of Elemento-Organic Chemistry,
Nankai University, Tianjin 300071, China
Received May 12, 2004
A toluene solution of C60 reacted with an equimolar quantity of M(dba)2 (M ) Pd, Pt; dba
) dibenzylideneacetone) and (η5-Ph2PC5H4)2Ru or with M(PPh3)4 and (η5-Ph2PC5H4)2Ru at
room temperature to give the dinuclear transition-metal fullerene complexes (η2-C60)M[(η5-
Ph2PC5H4)2Ru] (1, M ) Pd; 2, M ) Pt), whereas the o-dichlorobenzene solution of C60 reacted
with an equimolar amount of M(dba)2 and [(η5-Ph2PC5H4)2Co]+(PF6)- or with M(PPh3)4 and
[(η5-Ph2PC5H4)2Co]+(PF6)- under similar conditions to afford the dinuclear transition-metal
fullerene complexes (η2-C60)M[(η5-Ph2PC5H4)2Co]+(PF6)- (3, M ) Pd; 4, M ) Pt). In addition,
the related complex {[η5-Ph2P(O)C5H4]2Co}+(PF6)- (5) was prepared by oxidation of [(η5-Ph2-
PC5H4)2Co]+(PF6)- with an excess amount of aqueous peracetic acid in acetone at room
temperature. While 1-4 are the first examples of neutral and cationic dinuclear M/Ru and
M/Co (M ) Pd, Pt) fullerene complexes, 5 is the first organocobalt Cp complex containing a
phosphoryl substituent. All products 1-5 have been fully characterized by elemental analysis,
spectroscopy, and X-ray crystal diffraction techniques and, for 1 and 2, by cyclic voltammetry.
In tr od u ction
indirectly attached to the C60 cage. It is worthy of note
that 1-4 are the first neutral and ionic dinuclear M/Ru
and M/Co (M ) Pd, Pt) fullerene complexes, although a
wide variety of transition-metal fullerene complexes are
known.5-8 We also report the first organocobalt phos-
phoryl containing Cp complex, {[η5-Ph2P(O)C5H4]2Co}+-
(PF6)- (5), which was derived from oxidation of the
Transition-metal fullerene complexes are of great
interest with regard to the effects of the involved metals
on the chemical and physical properties of fullerenes,1
and they may fall into two major classes. The first class
includes the fullerene cores directly bonded to transition
metals, such as in (η2-C60)Pt(PPh3)2,2 whereas the
second class contains the fullerene cores indirectly
bonded to transition metals, such as in (η2-C60)[o-
(CH2)2C5H3-η5]Co(η4-C4Ph4).3 Recently, we reported a
series of dinuclear M/Fe (M ) Pd, Pt) fullerene com-
plexes, in which Pd or Pt is directly bonded to the C60
sphere and Fe is indirectly bound to the C60 sphere.4
Now, as a continuation of the synthetic and structural
studies of such heterodinuclear complexes, we report
another series of the dinuclear M/Ru and M/Co (M )
Pd, Pt) fullerene complexes (η2-C60)M[(η5-Ph2PC5H4)2-
Ru] (1, M ) Pd; 2, M ) Pt) and (η2-C60)M[(η5-Ph2-
PC5H4)2Co]+(PF6)- (3, M ) Pd; 4, M ) Pt), in which Pd
or Pt is directly bonded to the C60 cage and Ru or Co is
(5) For mononuclear fullerene derivatives, see for example: (a)
Balch, A. L.; Catalano, V. J .; Lee, J . W.; Olmstead, M. M.; Parkin, S.
R. J . Am. Chem. Soc. 1991, 113, 8953. (b) Balch, A. L.; Catalano, V.
J .; Lee, J . W.; Olmstead, M. M. J . Am. Chem. Soc. 1992, 114, 5455. (c)
Sawamura, M.; Iikura, H.; Nakamura, E. J . Am. Chem. Soc. 1996,
118, 12850. (d) Hsu, H.-F.; Du, Y.; Albrecht-Schmitt, T. E.; Wilson, S.
R.; Shapley, J . R. Organometallics 1998, 17, 1756. (e) Bengough, M.
N.; Thompson, D. M.; Baird, M. C.; Enright, G. D. Organometallics
1999, 18, 2950. (f) Song, L.-C.; Liu, J .-T.; Hu, Q.-M.; Weng, L.-H.
Organometallics 2000, 19, 1643.
(6) For dinuclear fullerene derivatives, see for example: (a) Balch,
A. L.; Lee, J . W.; Noll, B.; Olmstead, M. M. J . Am. Chem. Soc. 1992,
114, 10984. (b) Balch, A. L.; Lee, J . W.; Olmstead, M. M. Angew. Chem.,
Int. Ed. Engl. 1992, 31, 1356. (c) Zhang, S.; Brown, T. L.; Du, Y.;
Shapley, J . R. J . Am. Chem. Soc. 1993, 115, 6705. (d) Song, L.-C.; Liu,
J .-T.; Hu, Q.-M.; Wang, G.-F.; Zanello, P.; Fontani, M. Organometallics
2000, 19, 5342. (e) Mavunkal, I. J .; Chi, Y.; Peng, S.-M.; Lee, G.-H.
Organometallics 1995, 14, 4454.
(7) For trinuclear fullerene derivatives, see for example: (a) Hsu,
H.-F.; Shapley, J . R. J . Am. Chem. Soc. 1996, 118, 9192. (b) Park, J .
T.; Song, H.; Cho, J .-J . Chung, M.-K.; Lee, J .-H.; Suh, I.-H. Organo-
metallics 1998, 17, 227. (c) Song, H.; Lee, K.; Park, J . T.; Chio, M.-G.
Organometallics 1998, 17, 4477.
(8) For multinuclear fullerene derivatives, see for example: (a)
Fagan, P. J .; Calabrese, J . C.; Malone, B. J . Am. Chem. Soc. 1991,
113, 9408. (b) Balch, A. L.; Hao, L.; Olmstead, M. M. Angew. Chem.,
Int. Ed. Engl. 1996, 35, 188. (c) Lee, K.; Hsu, F.-F.; Shapley, J . R.
Organometallics 1997, 16, 3876. (d) Lee, K.; Shapley, J . R. Organo-
metallics 1998, 17, 3020. (e) Lee, K.; Choe, Z.-H.; Cho, Y.-J .; Song, H.;
Park, J . T. Organometallics 2001, 20, 5564. (f) Lee, G.; Cho, Y.-J .; Park,
B. K.; Lee, K.; Park, J . T. J . Am. Chem. Soc. 2003, 125, 13920.
* To whom correspondence should be addressed. Fax: 0086-22-
23504853. E-mail: lcsong@nankai.edu.cn.
(1) For reviews, see for example: (a) Fagan, P. J .; Calabrese, J . C.;
Malone, B. Acc. Chem. Res. 1992, 25, 134. (b) Sliwa, W. Transition
Met. Chem. 1996, 21, 583. (c) Balch, A. L.; Olmstead, M. M. Chem.
Rev. 1998, 98, 2123. (d) Bowser, J . R. Adv. Organomet. Chem. 1994,
36, 57.
(2) Fagan, P. J .; Calabrese, J . C.; Malone, B. Science 1991, 252, 1160.
(3) Iyoda, M.; Sultana, F.; Sasaki, S.; Butenscho¨n, H. Tetrahedron
Lett. 1995, 36, 579.
(4) Song, L.-C.; Wang, G.-F.; Liu, P.-C.; Hu, Q.-M. Organometallics
2003, 22, 4593.
10.1021/om049667a CCC: $27.50 © 2004 American Chemical Society
Publication on Web 07/30/2004

Transition-Metal Fullerene Complexes
Organometallics, Vol. 23, No. 18, 2004 4193
Sch em e 1
diphosphine ligand in [(η5-Ph2PC5H4)2Co]+(PF6)-, used
in this paper for preparing fullerene complexes 3 and
4.
Resu lts a n d Discu ssion
F igu r e 1. Cyclic voltammograms recorded at a platinum
electrode in CH2Cl2 solutions of (a) complex 1 (0.5 × 10-3
mol dm-3), (b) complex 2 (0.5 × 10-3 mol dm-3), and (c)
C60 (0.4 × 10-3 mol dm-3). The supporting electrolyte was
Syn th esis a n d Ch a r a cter iza tion of (η2-C60)M[(η5-
P h 2P C5H4)2Ru ] (1, M ) P d ; 2, M ) P t). We found that
n-Bu4NPF6 (0.1 mol dm-3), the scan rate was 0.2 V s-1
and T ) -10 °C.
,
C
60 reacted with an equimolar amount of M(dba)2 (M )
Pd, Pt; dba ) dibenzylideneacetone) in toluene at room
temperature followed by treatment of the intermediate
Ta ble 1. F or m a l Electr od e P oten tia ls (in V, vs
SCE) a n d P ea k -to-P ea k Sep a r a tion s (in m V) for
th e Red ox Ch a n ges Exh ibited by th e
9
10
products (C60Pd)n and (C60Pt)n with 1,1′-bis(diphen-
ylphosphino)ruthenocene (dppr) to produce the transi-
tion-metal fullerene complexes 1 and 2, whereas they
could be also produced by reaction of an equimolar
quantity of C60 with M(PPh3)4 (M ) Pd, Pt) in toluene
at room temperature, followed by treatment of the
intermediate products (η2-C60)Pd(PPh3)211 and (η2-C60)-
Meta llofu ller en es (η2-C60)M(d p p r ) (1, M ) P d ; 2, M
) P t) a n d C60 in CH2Cl2 Solu tion a t -10 °C
fullerene-centered redns
E°′0/-
Ep
76
113
79
E°′-/2-
Ep
E°′2-/3-
Ep
2
1
2
C60
-0.85
-0.86
-0.64
-1.22
-1.25
-1.02
71
90
73
-1.69
-1.71
-1.46
95
85
78
Pt(PPh3)2 with the organometallic diphosphine dppr
(Scheme 1).
Complexes 1 and 2 are new and have been character-
1
ized by elemental analysis, H NMR, 31P NMR, UV-
reversible or quasi-reversible fullerene-centered reduc-
tions, which are shifted by about 0.2 V toward more
negative potential values with respect to the corre-
sponding processes of free C60. Such electrochemical
behavior is quite similar to that previously observed for
the related metallofullerenes, in which the coordinated
metal fragment pushes electron density toward the
fullerene ligand.6d,14,15 Also, it can be seen that the three
negative potential values of complex 1 are slightly less
than the corresponding values of complex 2. Apparently,
this implies that the η2-coordinated metal fragment Pt-
(dppr) in 2 is a more effective electron-pushing group
than the η2-coordinated metal fragment Pd (dppr) in 1.
The molecular structures of 1 and 2 were unambigu-
ously confirmed by their single-crystal X-ray studies.
The molecular diagrams of 1 and 2 are shown in Figures
2 and 3, whereas Table 2 lists their selected bond
lengths and angles. In fact, 1 and 2 are isostructural.
While the ruthenocene diphosphine dppr ligand chelates
to the Pd(1) or Pt(1) atom through its two phosphorus
atoms P(1) and P(2), the C60 ligand coordinates to Pd-
(1) or Pt(1) in an η2 fashion via its C(1)-C(2) bond
between two six-membered rings. The C(1)-C(2) bond
length (1.493(12) Å for 1 and 1.500(16) Å for 2) is very
close to the corresponding values observed in (η2-C60)-
Pd(dppf) (1.466(11) Å) and (η2-C60)Pt (dppf) (1.513(7) Å),4
which are much longer than that of free C60 (1.38 Å)16
owing to metal-to-C60 π-back-donation. The zerovalent
Pd(1) atom in 1 or Pt(1) in 2 is at the center of a tetragon
constituted by C(1), C(2), P(1), and P(2) atoms, and all
vis, IR, CV, and X-ray diffraction analysis. For example,
the IR spectra of 1 and 2 showed four characteristic
absorption bands in the range 1434-526 cm-1 for their
C
60 cores,12 whereas the 1H NMR spectra of 1 and 2 each
displayed one singlet at ca. 4.80 ppm for their substi-
tuted Cp rings. While the 31P NMR spectrum of 1
exhibited one singlet at 21.72 ppm for its two identical
P atoms, the spectrum of 2 displayed one triplet due to
the 195Pt-31P coupling at 25.32 ppm for its two identical
P atoms. The UV-vis spectra of 1 and 2 are virtually
identical with each other, showing four absorption bands
in the region 287-624 nm. In comparison to free C60,
the band at ca. 440 nm is newly generated, which
suggests that the C60 ligand is coordinated to the Pd or
Pt atom in an η2 fashion.13
Although some electrochemical studies on metallo-
fullerenes containing dppf ligands have been per-
formed,6d,14 no such studies on the dppr-containing
metallofullerenes have been reported so far. Table 1 and
Figure 1 compare the cyclic voltammetric responces
exhibited by complexes 1 and 2 with that of free C60 in
dichloromethane, at -10 °C. As can be seen from Table
1 and Figure 1, complexes 1 and 2 display three
(9) Nagashima, H.; Nakaoka, A.; Saito, Y.; Kato, M.; Kawanishi, T.;
Itoh, K. J . Chem. Soc., Chem. Commun. 1992, 377.
(10) Nagashima, H.; Kato, Y.; Yamaguchi, H.; Kimura, E.; Kawan-
ishi, T.; Kato, M.; Saito, Y.; Haga, M.; Itoh, K. Chem. Lett. 1994, 1207.
(11) Bashilov, V. V.; Petrovskii, P. V.; Sokolov, V. I.; Lindeman, S.
V.; Guzey, I. A.; Struchkov, Y. T. Organometallics 1993, 12, 991.
(12) Hare, J . P.; Dennis, T. J .; Kroto, H. W.; Taylor, R.; Allaf, A.
W.; Balm, S.; Walton, D. R. M. J . Chem. Soc., Chem. Commun. 1991,
412.
(13) Hirsch, A.; Gro¨sser, T.; Skiebe, A.; Soi, A. Chem. Ber. 1993,
126, 1061.
(14) Bashilov, V. V.; Magdesieva, T. V.; Kravchuk, D. N.; Petrovskii,
P. V.; Ginzburg, A. G.; Butin, K. P.; Sokolov, V. I. J . Organomet. Chem.
2000, 599, 37.
(15) Zanello, P.; Laschi, F.; Fontani, M.; Song, L.-C.; Zhu, Y.-H. J .
Organomet. Chem. 2000, 593-594, 7.
(16) Burgi, H. B.; Blanc, E.; Schwarzenbach, D.; Liu, S.; Lu, Y.;
Kappes, M. M.; Ibers, J . A. Angew. Chem., Int. Ed. Engl. 1992, 31,
640.

4194 Organometallics, Vol. 23, No. 18, 2004
Song et al.
Ta ble 2. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 1 a n d 2
Compound 1
Pd(1)-C(1)
Pd(1)-C(2)
Pd(1)-P(2)
Pd(1)-P(1)
P(1)-C(61)
P(2)-C(78)
2.140(8)
2.139(8)
2.332(2)
2.335(3)
1.833(8)
1.809(8)
C(1)-C(2)
1.493(12)
1.500(11)
1.462(11)
2.151(8)
2.153(8)
1.453(11)
C(1)-C(6)
C(2)-C(12)
Ru(1)-C(61)
Ru(1)-C(78)
C(1)-C(9)
C(1)-Pd(1)-C(2)
C(1)-Pd(1)-P(2)
C(2)-Pd(1)-P(2)
C(61)-Ru(1)-C(62)
40.8(3) C(1)-Pd(1)-P(1)
147.5(3) C(2)-Pd(1)-P(1)
107.1(2) P(2)-Pd(1)-P(1)
105.5(3)
146.0(2)
106.89(8)
38.7(3) C(61)-Ru(1)-C(78) 114.3(3)
Compound 2
Pt(1)-C(1)
Pt(1)-C(2)
Pt(1)-P(2)
Pt(1)-P(1)
P(1)-C(61)
P(2)-C(66)
2.095(10)
C(1)-C(2)
1.500(16)
1.524(16)
1.442(16)
2.160(11)
2.131(12)
1.464(16)
2.127(11)
2.287(3)
2.287(3)
1.820(11)
1.829(11)
C(1)-C(6)
C(2)-C(12)
Ru(1)-C(61)
Ru(1)-C(66)
C(1)-C(9)
C(61)-Ru(1)-C(65)
C(1)-Pt(1)-C(2)
C(1)-Pt(1)-P(2)
C(2)-Pt(1)-P(2)
38.4(4) C(61)-Ru(1)-C(66) 113.4(4)
F igu r e 2. ORTEP diagram of 1 with ellipsoids drawn at
30% probability.
41.6(4) C(1)-Pt(1)-P(1)
148.1(3) C(2)-Pt(1)-P(1)
106.8(3) P(2)-Pt(1)-P(1)
105.3(3)
146.6(3)
106.46(12)
Sch em e 2
treatment of the intermediate products (η2-C60)Pd-
(PPh3)2 and (η2-C60)Pt(PPh3)2 with (dppc)+(PF6)- to
afford the transition-metal fullerene complexes 3 and
4 (Scheme 2).
11
2
Complexes 3 and 4 are new heterodinuclear fullerene
complexes, which were fully characterized by elemental
1
analysis, IR, H NMR, 13C NMR, 31P NMR, and UV-
F igu r e 3. ORTEP diagram of 2 with ellipsoids drawn at
vis spectra, as well as by X-ray diffraction analysis. The
IR spectra of 3 and 4 showed four absorption bands in
the range 1436-523 cm-1 characteristic of their C60
spheres,12 while the UV-vis spectra of 3 and 4 displayed
five absorption bands in the region 300-700 nm typical
of their C60 ligands being coordinated to transition
metals in an η2 manner.13 The1H NMR spectra of 3 and
4 showed two singlets at 5.92 and 6.07 ppm or at 5.98
and 6.08 ppm for their H3/H4 and H2/H5 protons of the
substituted Cp rings, respectively. The 31P NMR spectra
of 3 and 4 along with that of free (dppc)+(PF6)- are
shown in Figure 4. As can be seen in Figure 4, complex
3 diplayed one singlet at ca. 14 ppm for its two identical
P atoms in the (dppc)+ cation, whereas 4 exhibited one
triplet at ca. 20 ppm for its two P atoms in the (dppc)+
30% probability.
five atoms are nearly coplanar with a mean deviation
of 0.0436 Å for 1 and 0.0448 Å for 2, respectively. In
addition, the two substituted Cp rings in the ru-
thenocene moiety of 1 or 2 (dihedral angle 4.7 or 5.7°),
like those in the ferrocene unit of (η2-C60)Pd(dppf) or
(η2-C60)Pt(dppf) (dihedral angle ) 2.3° or 3.0°), are
almost parallel to each other.4 The distances between
the two metal centers in 1 (Ru‚‚‚Pd ) 4.276 Å) and in 2
(Ru‚‚‚Pt ) 4.264 Å) are slightly longer than the corre-
sponding ones in (η2-C60)Pd(dppf) (Fe‚‚‚Pd ) 4.196 Å)
and (η2-C60)Pt(dppf) (Fe‚‚‚Pt ) 4.218 Å).4 Thus, there
are no metal-metal interactions in 1 and 2, since such
a large distance between Ru and Pd or between Ru and
Pt is far greater than the sum of their van der Waals
radii.
cation due to coupling between 195Pt and 31P (J Pt-P
)
3957 Hz). Either 3 or 4 showed one quintet (though
theoretically a heptet) at ca. -144 ppm for its P atom
in the (PF6)- anion due to coupling between 31P and 19F
(J P-F ) 711 Hz). In addition, the two P atoms of (dppc)+
in free (dppc)+(PF6)-, in contrast to those of the coor-
dinating (dppc)+ in 3 and 4, resonated at much higher
field (ca. -24 ppm), whereas the resonance signals of
the P atom in the (PF6)- anion of free (dppc)+(PF6)-
appeared as one heptet at ca. -144 ppm, as opposed to
Syn th esis a n d Ch a r a cter iza tion of (η2-C60)M[(η5-
P h 2P C5H4)2Co]+(P F 6)- (3, M ) P d ; 4, M ) P t). We
further found that an equimolar quantity of C60 reacted
with M(dba)2 in o-dichlorobenzene at room temperature,
followed by treatment of the intermediate products [C60-
9
10
Pd]n and [C60Pt]n with 1,1′-bis(diphenylphosphino)-
cobaltocenium hexafluorophosphate (hereafter denoted
as (dppc)+(PF6)-) or reacted with M(PPh3)4 followed by

Transition-Metal Fullerene Complexes
Organometallics, Vol. 23, No. 18, 2004 4195
F igu r e 6. ORTEP diagram of 4 with ellipsoids drawn at
30% probability.
F igu r e 4. 31P NMR spectra of complexes 3 and 4 and
(dppc)+(PF6)-.
Ta ble 3. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 3 a n d 4
Compound 3
Pd(1)-C(1)
Pd(1)-C(2)
Pd(1)-P(2)
Pd(1)-P(1)
P(1)-C(61)
Co(1)-C(61)
2.130(6)
2.116(6)
2.3080(17)
2.3084(19)
1.812(6)
2.042(6)
C(1)-C(2)
C(1)-C(6)
C(2)-C(12)
C(2)-C(3)
C(1)-C(9)
Co(1)-C(78)
1.459(8)
1.462(9)
1.4457(9)
1.455(8)
1.463(9)
2.068(6)
C(1)-Pd(1)-C(2)
C(1)-Pd(1)-P(2)
C(2)-Pd(1)-P(2)
40.2(2)
C(1)-Pd(1)-P(1)
145.21(16)
105.23(18)
106.15(6)
108.09(16) C(2)-Pd(1)-P(1)
148.23(18) P(2)-Pd(1)-P(1)
C(61)-Co(1)-C(62) 41.1(2)
C(61)-Co(1)-C(78) 113.3(2)
Compound 4
2.133(7)
Pt(1)-C(1)
Pt(1)-C(2)
Pt(1)-P(2)
Pt(1)-P(1)
P(1)-C(61)
Co(1)-C(61)
C(1)-C(2)
C(1)-C(6)
C(2)-C(12)
C(2)-C(3)
C(1)-C(9)
Co(1)-C(78)
1.494(9)
2.091(6)
2.2753(18)
2.269(2)
1.814(7)
2.030(6)
1.4584(10)
1.473(10)
1.475(10)
1.482(10)
2.065(7)
C(1)-Pt(1)-C(2)
C(1)-Pt(1)-P(2)
C(2)-Pt(1)-P(2)
41.4 (2)
108.09(18) C(2)-Pt(1)-P(1)
149.46(19) P(2)-Pt(1)-P(1)
C(1)-Pt(1)-P(1)
146.24(18)
105.08(19)
105.15(7)
F igu r e 5. ORTEP diagram of 3 with ellipsoids drawn at
30% probability.
C(61)-Co(1)-C(62) 41.3(3)
C(61)-Co(1)-C(78) 112.4(3)
dppr in 1 and 2, belong to a parallel type of sandwich
structure, since the dihedral angle between the two
substituted Cp rings is only 3.5° for 3 and 2.6° for 4,
respectively. It is also believed that no metal-metal
interactions exist in 3 and 4, since the distances between
the two metals in 3 (Co‚‚‚Pd ) 4.113 Å) and in 4 (Co‚‚
‚Pt ) 4.120 Å) are close to those in 1, 2, and (η2-C60)M-
(dppf) (M ) Pd, Pt)4 and are far greater than the sum
of van der Waals radii of Co and M (M ) Pd, Pt).
Syn t h esis a n d Ch a r a ct er iza t ion of {[η5-P h 2P -
(O)C5H4]2Co}+(P F 6)-(5). Initially, we tried to obtain
the C70 analogue of complex 3, (η2-C70)Pd[(η5-Ph2PC5H4)2-
Co]+(PF6)-, by means of the interlayer diffusion reaction
process, which involves an o-dichlorobenzene solution
of an equimolar amount of (dppc)+(PF6)- being diffused
into a chlorobenzene solution of C70 and Pd(PPh3)4 for
1 week. However, it was unexpected that a very small
amount of the oxidized derivative of (dppc)+(PF6)-,
namely 5, was obtained. Apparently, the oxygen atoms
in 5 originated from atmospheric O2, because the
diffusion reaction process was carried out without
thorough exclusion of air. Considering that air is a very
a quintet for the P atom in (PF6)- of 3 and 4. The 13C
NMR spectra of 3 and 4 showed 15 and 17 signals for
their C60 spheres, in which one signal at ca. 90 ppm can
be assigned to the two C atoms attached to Pd or Pt
and the others in the range 140-157 ppm to the
remaining 58 C atoms of the C60 sphere.
The structures of 3 and 4 were unequivocally con-
firmed by X-ray diffraction analysis. As can be seen in
Figures 5 and 6, they contain a molecule of (dppc)+(PF6)-
chelated to Pd(1) for 1 and Pt(1) for 2 through the P(1)
and P(2) atoms of the (dppc)+ cation; the molecule of
C60 is coordinated to Pd(1) for 3 and Pt(1) for 4 in an η2
fashion through the C(1)-C(2) 6:6 bond. Table 3 shows
some of their geometric parameters, which are very close
to each other. Actually, 3 and 4 are also isostructural.
It is noteworthy that both C(1)-C(2) 6:6 bonds in 3 and
4 are considerably longer than that in free C60 (1.38 Å).16
Obviously, such elongations are due to coordination of
the 6:6 bond with Pd(1) or Pt(1). In addition, the
geometry around Pd(1) or Pt(1) is square planar, while
the geometry of the P(3) atom in the anion (PF6)- is
octahedral. The (dppc)+ ligands in 3 and 4, similar to

4196 Organometallics, Vol. 23, No. 18, 2004
Song et al.
Ta ble 4. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 5
Co(1)-C(15)
Co(1)-C(18)
P(1)-O(1)
2.018(6)
2.033(5)
1.459(3)
1.796(6)
P(1)-C(13)
P(2)-O(2)
P(2)-C(22)
P(3)-F(1)
1.811(6)
1.469(4)
1.809(6)
1.572(4)
P(1)-C(1)
C(15)-Co(1)-C(17)
68.1(3) O(1)-P(1)-C(13)
113.0(2)
112.8(2)
C(15)-Co(1)-C(21) 112.4(3) O(2)-P(2)-C(22)
P(1)-C(13)-Co(1)
O(1)-P(1)-C(1)
125.3(3) P(2)-C(22)-Co(1) 123.5(3)
114.4(2) F(2)-P(3)-F(1) 90.4(3)
1.643 Å for 4, and 1.635 Å for 5, and (iii) the P atom in
the (PF6)- anion of 3, 4, or 5 possesses an octahedral
configuration with comparable P-F bond lengths and
F-P-F bond angles. However, while the two Ph2P(O)
substituents in the cation {[η5-Ph2P(O)C5H4]2Co}+ of 5
are trans to each other with respect to the Co metal
center, the two Ph2P substituents in the cation {[η5-Ph2-
PC5H4]2Co}+ of 3 or 4 are cis to each other, due to their
chelation with Pd or Pt. In addition, the PdO bond
lengths of P(1)-O(1) (1.459 (3) Å) and P(2)-O(2) (1.469(4)
Å) are close to those reported for Ph3PdO (1.483-1.494
Å17) and [η5-Ph2P(O)C5H4]2Fe‚2H2O (1.488 (3) Å).18
F igu r e 7. ORTEP diagram of 5 with ellipsoids drawn at
30% probability.
Sch em e 3
Su m m a r y
We have synthesized the first dinuclear transition
metal M/Ru and M/Co (M ) Pd, Pt) fullerene complexes
1-4 and the related complex 5 in high yield. All the
structures of 1-5 have been confirmed by X-ray dif-
fraction crystallography as well as characterized by
elemental analysis and various spectroscopic methods.
While 1 and 2 are neutral fullerene complexes, 3 and 4
are ionic fullerene complexes, each containing a di-
nuclear metallofullerene cation and the complex anion
(PF6)-. The dihedral angle between the two substituted
Cp rings in the metallocene moieties of 1-5 is only 0.2-
5.7°, which means that they still belong to parallel
sandwich structural metallocenes. Through comparison
of the 31P NMR spectra of 3-5 with that of the free
ligand (dppc)+(PF6)-, it is shown that the two identical
P atoms of (dppc)+ in 3-5 are much more deshielded
than those of free (dppc)+, whereas the chemical shift
of the P atom of (PF6)- in 3-5 remains essentially the
same as that of the P atom of (PF6)- in the free ligand
(dppc)+(PF6)-. Apparently, this is because each of the
two P atoms of (dppc)+ in 5 is bonded to an electroneg-
ative O atom, whereas the two P atoms of (dppc)+ in 3
and 4 are chelated to Pd or Pt, which is in turn attached
to the electron-withdrawing C60 ligand. Finally, it is
worth pointing out that the P-donor ligand (dppc)+(PF6)-
has been converted to the corresponding O-donor ligand
5, which may have uses different from the P-donor
ligand in transition-metal chemistry.
weak oxidant for oxidizing (dppc)+(PF6)- (note that
(dppc)+(PF6)- was completely recovered after its o-
dichlorobenzene solution was stirred in air at room
temperature for 24 h), we chose a stronger oxidant, i.e.,
peracetic acid, to improve the yield of 5. Fortunately, it
was found that the diphosphine complex (dppc)+(PF6)-
reacted in acetone with an excess amount of aqueous
peracetic acid at room temperature for 2 h to produce 5
in nearly quantitative yield (Scheme 3).
Complex 5 is an air-stable and black crystalline solid,
which has been fully characterized by elemental analy-
1
sis, IR, H NMR, 31P NMR, and X-ray crystallography.
For example, while the IR spectrum of 5 showed one
absorption band at 1206 cm-1 for its PdO functionality,
the 1H NMR spectrum of 5 displayed two singlets at
5.98 and 6.21 ppm for H3/H4 and H2/H5 protons in its
substituted Cp rings. It follows that the 1H NMR signals
of these Cp protons in 5 are markedly shifted toward
lower field, in comparison with those of the correspond-
ing protons in its starting material (dppc)+(PF6)- (two
singlets at 5.59 and 5.97 ppm). Apparently, this is
consistent with the substituent Ph2PdO in 5 being a
stronger electron-withdrawing group than is Ph2P in
(dppc)+(PF6)-. The 31P NMR spectrum of 5 showed one
singlet at ca. 24 ppm for its P atom in the (PF6)- anion.
Therefore, the 31P NMR behavior of 5 is similar to that
of 3 but different from that of the free (dppc)+(PF6)-
ligand as described above.
The molecular structure of 5 confirmed by an X-ray
crystallographic study is shown in Figure 7, while its
selected bond lengths and angles are given in Table 4.
As can be seen in Figure 7, this molecule indeed consists
of the cation {[η5-Ph2P(O)C5H4]2Co}+ and the anion
(PF6)-. In fact, the structure of 5 is very similar to that
of the coordinated (dppc)+(PF6)- in 3 and 4. For ex-
ample, (i) the two substituted Cp rings are staggered
and essentially parallel with a dihedral angle of 3.5°
for 3, 2.6° for 4, and 0.2° for 5, (ii) the distance between
the Co atom and the center of Cp ring is 1.640 Å for 3,
Exp er im en ta l Section
Gen er a l Com m en ts. All reactions were carried out under
an atmosphere of highly purified nitrogen using standard
Schlenk or vacuum-line techniques. While o-dichlorobenzene
was dried with CaH2, toluene and hexane were distilled under
(17) Gilheany, D. G. In The Chemistry of Organophosphorus Com-
pounds; Hartley, F. R., Ed.; Wiley: Chichester, U.K., 1992; Vol. 2,
Chapter 1, pp 9-10.
(18) Fang, Z.-G.; Hor, T. S. A.; Wen, Y. S.; Liu, L. K.; Mak, T. C. W.
Polyhedron 1995, 14, 2403.

Transition-Metal Fullerene Complexes
Organometallics, Vol. 23, No. 18, 2004 4197
nitrogen from sodium/benzophenone ketyl. All solvents were
bubbled for at least 15 min before use. C60 (99.9%) was
available commercially. Pd(PPh3)4,19 Pt(PPh3)4,20 Pd(dba)2,21 Pt-
(dba)2,22 dppr,23 and (dppc)+(PF6)- 24 were prepared according
to the reported procedures. Melting points were determined
on a Yanaco MP-500 melting point apparatus. Elemental
analyses were performed on an Elementar Vario EL analyzer.
IR and UV-vis spectra were recorded on a Bio-Rad FTS 135
and a Shimadzu TU 1901 spectrophotometer, respectively. 1H
NMR and 31P NMR spectra were obtained on a Bruker AC-P
200 and Bruker Avance 300 spectrometer, respectively.
P r epar ation of (η2-C60)P d[(η5-P h 2P C5H4)2Ru ] (1). Meth od
i. A 100 mL three-necked flask equipped with a magnetic stir
bar, a rubber septum, and a nitrogen inlet tube was charged
with 36 mg (0.05 mmol) of C60 and 20 mL of toluene. To the
purple toluene solution of C60 was added 29 mg (0.05 mmol)
of Pd(dba)2, and then the mixture was stirred at room
temperature for 0.5 h to give a black suspension. To this
suspension was added 30 mg (0.05 mmol) of dppr, and the new
mixture was stirred for 1 h to give a green solution. The
solution was carefully layered with 60 mL of hexane. After
the mixture stood for 1 day, a dark green precipitate formed,
which was filtered, washed with hexane, and dried in vacuo.
A 45 mg amount (63%) of 1 as a dark green crystal was
obtained, mp >300 °C. Anal. Calcd for C94H28P2PdRu: C,
MHz, DMSO-d6, TMS): δ 5.92 (s, 4H, 2H3, 2H4), 6.07 (s, 4H,
2H2, 2H5), 7.18-7.85 (m, 20H, 4C6H5) ppm. 31P NMR (121.5
MHz, DMSO-d6, H3PO4): δ 14.17 (s, 2P), -144.07 (quintet,
J P-F ) 711 Hz, 1P) ppm. 13C NMR (100.6 MHz, DMSO-d6,
TMS): δ (C60) 88.76 (2C, Pd-C), 153.89 (4C, Pd-C-C), 147.19
(2C), 146.50 (2C), 145.59 (2C), 144.52 (2C), 144.22 (2C), 143.64
(4C), 143.44 (4C), 143.27 (2C), 142.70 (20C), 142.15 (4C),
141.70 (4C), 141.57 (4C), 140.89 (2C); δ (dppc)+ 134.30 (4C),
133.85 (8C), 131.14 (4C), 129.46 (8C), 105.55 (2C), 86.87 (8C)
ppm. UV-vis (acetone): λmax (log ꢀ) 324 (4.90), 332 (4.89), 438
(4.36), 613 (4.27), 659 (4.22) nm.
Meth od ii. This method is similar to the preparation of 1;
when 35 mg (0.05 mmol) of (dppc)+(PF6)- and 10 mL of
o-dichlorobenzene were used instead of dppr and toluene, 62
mg (81%) of 3 was obtained.
P r ep a r a tion of (η2-C60)P t[(η5-P h 2P C5H4)2Co]+(P F 6)-(4).
Meth od i. This method is similar to the preparation of 2; when
35 mg (0.05 mmol) of (dppc)+(PF6)- and 10 mL of o-dichlo-
robenzene were utilized instead of dppr and toluene, 80 mg
(99%) of 4 was produced as a dark green solid, mp >300 °C.
Anal. Calcd for C94H28CoF6P3Pt: C, 69.77; H, 1.74. Found: C,
69.82; H, 1.64. IR (KBr): νC 1436 (s), 1184 (m), 558 (s), 527
60
(vs); νCp 1098 (s), 1029 (m), 999 (m), 839 (vs) cm-1 1H NMR
.
(200 MHz, DMSO-d6, TMS): δ 5.98 (s, 4H, 2H3, 2H4), 6.08 (s,
4H, 2H2, 2H5), 7.17-7.91 (m, 20H, 4C6H5) ppm. 31P NMR
(121.5 MHz, DMSO-d6, H3PO4): δ 20.20 (t, J ) 3957 Hz, 2P),
-144.08 (quintet, J P-F ) 711 Hz, 1P) ppm. 13C NMR (100.6
MHz, DMSO-d6, TMS): δ (C60) 89.22 (2C, Pt-C), 156.48 (4C,
Pt-C-C), 147.15 (4C), 145.91 (2C), 144.54 (2C), 144.30 (4C),
143.92 (2C), 143.81 (4C), 143.58 (4C), 143.19 (2C), 142.74 (5C),
142.64 (4C), 142.44 (5C), 141.83 (4C), 141.55 (4C), 141.33(4C),
140.25 (4C); δ (dppc)+ 134.86 (4C), 133.69(8C), 131.09 (4C),
129.27 (8C), 105.00 (2C), 87.19 (8C) ppm. UV-vis (acetone):
λmax (log ꢀ) 323 (4.75), 331 (4.75), 437 (4.20), 602 (4.01), 640
(3.94) nm.
79.14; H, 1.98. Found: C, 79.08; H, 1.99. IR (KBr): νC 1434
60
(s), 1184 (m), 579 (m), 527 (vs); νCp 1096 (s), 1028 (m), 841
(m), 812 (s) cm-1 1H NMR (200 MHz, CS2/CDCl3, TMS): δ
.
4.76 (s, 8H, 2C5H4), 7.11-7.35 (m, 20H, 4C6H5) ppm. 31P NMR
(81 MHz, CS2/CDCl3, H3PO4): δ 21.72 (s, 2P) ppm. UV-vis
(C6H5Cl): λmax (log ꢀ) 289 (4.70), 334 (4.61), 443 (3.94), 624
(3.70) nm.
Meth od ii. The flask described above was charged with 54
mg (0.075 mmol) of C60 and 20 mL of toluene. To the purple
solution of C60 was added 87 mg (0.075 mmol) of Pd(PPh3)4,
and then the mixture was stirred at room temperature for 0.5
h to give a dark green solution. To this suspension was added
45 mg (0.075 mmol) of dppr, and the new mixture was stirred
at room temperature for 1 h. The same workup as in method
i gave 97 mg (91%) of 1.
Meth od ii. This method is similar to the preparation of 2;
when 35 mg (0.05 mmol) of (dppc)+(PF6)- and 10 mL of
o-dichlorobenzene were employed in place of dppr and toluene,
71 mg (88%) of 4 was obtained.
P r ep a r a tion of {[η5-P h 2P (O)C5H4]2Co}+(P F 6)- (5). To a
solution of 35 mg (0.5 mmol) of (dppc)+(PF6)- in 10 mL of
acetone was added 3.80 mL (ca. 5 mmol) of aqueous peracetic
acid freshly prepared from acetic acid and hydrogen peroxide.25
The mixture was stirred at room temperature for 2 h, during
which time the color of the mixture changed from brown-yellow
to brown-red. After the solvents were removed at reduced
pressure, 20 mL of H2O and 30 mL of CH2Cl2 were added. The
new mixture was stirred thoroughly to give an aqueous phase
and a CH2Cl2 phase. The CH2Cl2 phase was separated and
dried over anhydrous Na2SO4. Removal of Na2SO4 and CH2-
Cl2 gave a black residue, which was redissolved in 5 mL of
CH2Cl2. This solution was carefully layered with 20 mL of
hexane overnight to give 5 as a black crystalline solid, mp
218-220 °C. Anal. Calcd for C34H28CoF6O2P3: C, 55.60; H, 3.84.
Found: C, 55.78; H, 3.95. IR (KBr): νPdO 1206 (s); νCp 1102
P r epar ation of (η2-C60)P t[(η5-P h 2P C5H4)2Ru ] (2). Meth od
i. Similar to the preparation of 1, when 33 mg (0.05 mmol) of
Pt(dba)2 was used instead of Pd(dba)2, 45 mg (60%) of 2 as a
dark green crystal was obtained; mp >300 °C. Anal. Calcd for
C
94H28P2PtRu: C, 74.51; H, 1.86. Found: C, 74.35; H, 2.09.
IR (KBr): νC 1434 (s), 1185 (m), 579 (m), 526 (vs); νCp 1098
60
1
(s), 1028 (s), 838 (m), 810 (s) cm-1. H NMR (200 MHz, CS2/
CDCl3, TMS): δ 4.81 (s, 8H, 2C5H4), 7.12-7.35 (m, 20H, 4C6H5)
ppm. 31P NMR (81 MHz, CS2/CDCl3, H3PO4): δ 25.32 (t, J P-Pt
) 4012 Hz, 2P) ppm. UV-vis (C6H5Cl): λmax (log ꢀ) 287 (4.70),
333 (4.53), 441 (3.95), 610 (3.62) nm.
Meth od ii. This method is similar to the preparation of 1;
when 94 mg (0.075 mmol) of Pt(PPh3)4 was used instead of
Pd(PPh3)4, 105 mg (92%) of 2 was obtained.
P r ep a r a tion of (η2-C60)P d [(η5-P h 2P C5H4)2Co]+(P F 6)- (3).
Meth od i. This method is similar to the preparation of 1; when
35 mg (0.05 mmol) of (dppc)+(PF6)- and 10 mL of o-dichlo-
robenzene were employed in place of dppr and toluene, 72 mg
(94%) of 3 was obtained as a dark green solid, mp >300 °C.
Anal. Calcd for C94H28CoF6P3Pd: C, 73.82; H, 1.85. Found: C,
(m), 1040 (m), 998 (m), 839 (vs) cm-1 1H NMR (200 MHz,
.
DMSO-d6, TMS): δ 5.98 (s, 4H, 2H3, 2H4), 6.21 (s, 4H, 2H2,
2H5), 7.59-7.82 (m, 20H, 4C6H5) ppm. 31P NMR (81.0 MHz,
DMSO-d6, H3PO4): δ 24.03 (s, 2P), -139.18 (quintet, J P-F
711 Hz, 1P) ppm.
)
73.73; H, 1.88. IR (KBr): νC 1436 (s), 1185 (m), 558 (s), 523;
60
Electr och em istr y. Cyclic voltammetry measurements were
performed using a BAS-100B electrochemical analyzer and
were carried out in dichloromethane solution containing 0.1
mol dm-3 n-Bu4NPF6 using a glassy-carbon working electrode
and a platinum-wire counter electrode. All the potential values
are referred to the saturated calomel electrode (SCE).
1
νCp 1096 (s), 1028 (m), 999 (m), 840 (vs) cm-1. H NMR (200
(19) Malatesta, L.; Angoletta, M. J . Chem. Soc. 1957, 1186.
(20) Malatesta, L.; Cariello, C. J . Chem. Soc. 1958, 2323.
(21) Takahashi, Y.; Ito, T.; Sakai, S.; Ishii, Y. J . Chem. Soc. D 1970,
1065.
(22) Cherwinski, W. J .; J ohnson, B. F. G.; Lewis, J . J . Chem. Soc.,
Dalton Trans. 1974, 1405.
(23) Li, S.;Wei, B.; Low, P. M. N.; Lee, H. K.; Hor, T. S. A.; Xue, F.;
Mak, T. C. W. J . Chem. Soc., Dalton Trans. 1997, 1289.
(24) Townsend, J . M.; Reingold, I. D.; Kendall, M. C. R.; Spencer,
T. A. J . Org. Chem. 1975, 20, 2976.
An argon atmosphere was continuously maintained above
the solution while the experiments were in progress. The
(25) Phillips, B.; Starcher, P. S,; Ash, B. D. J . Org. Chem. 1959, 23,
1823.

4198 Organometallics, Vol. 23, No. 18, 2004
Ta ble 5. Cr ysta l Da ta a n d Str u ctu r e Refin em en t Deta ils for 1-5
Song et al.
1
2
3
4
5
mol formula
C
94H28P2PdRu‚
0.5C6H6‚
C94H28P2PtRu‚
0.5C6H6‚
C94H28CoF6P3Pd‚
0.5C6H5Me‚
0.75C6H5Cl‚
0.75C6H4Cl2
1770.13
293(2)
C94H28CoF6P3Pt‚
0.5C6H5Me‚
0.75C6H5Cl‚
0.75C6H4Cl2
1858.82
293(2)
C34H28CoF6O2P3
1.25H2O
1.75H2O
mol wt
temp/K
1488.15
293(2)
1585.85
293(2)
734.4
293(2)
cryst syst
space group
monoclinic
P21/c
monoclinic
P21/c
monoclinic
P21/c
monoclinic
P21/c
monoclinic
P21/n
a/Å
b/Å
c/Å
14.015(4)
24.361(7)
19.962(6)
99.493(7)
6722(4)
4
13.974(9)
24.285(16)
19.922(14)
99.279(12)
6672(8)
4
14.747(4)
24.155(9)
19.768(6)
90.541(10)
7041(4)
14.791(4)
24.338(7)
19.764(5)
90.608(5)
7114(3)
12.134(3)
10.738(3)
24.877(7)
103.488(6)
3151.9(16)
4
â/deg
V/Å3
Z
4
4
Dc/g cm-3
1.471
1.579
1.670
1.735
1.548
scan type
ω-2θ
0.595
ω-2θ
2.425
ω-2θ
0.721
ω-2θ
2.425
ω-2θ
0.764
abs coeff/mm-1
F(000)
2982
3130
3552
3680
1496
2θmax/deg
no. of rflns
50
34 270
50
25 827
50
29 373
50
29 808
50.06
10 971
no. of indep rflns
11 791
0.962
11 282
1.068
11 873
1.02
11 883
1.04
5558
0.997
goodness of fit on F2
no. of data/restraints/params
R
11 791/102/952
0.0730
11 282/150/970
0.0798
11 873/1428/1325
0.0642
11 883/1416/1325
0.0521
5558/0/415
0.0733
Rw
0.1280
0.703 and -0.707
0.1686
3.134 and -2.712
0.1225
0.707 and -0.411
0.0957
1.062 and -1.279
0.1087
0.573 and -0.283
largest diff peak and hole/e Å-3
glassy-carbon working electrode surface was polished with 0.05
mm alumina, sonicated in distilled water, and air-dried
immediately before use.
methods using the SHELXS-97 program and refined by full-
matrix least-squares techniques (SHELXL-97) on F2. Hydrogen
atoms were located by using the geometric method. All
calculations were performed on a Bruker Smart computer.
Details of the crystals, data collections, and structure refine-
ments are summarized in Table 5.
X-r a y Cr ysta llogr a p h y of 1-5. While single crystals of 1
and 2 suitable for X-ray diffraction analysis were obtained by
slow diffusion of hexane into a toluene solution of 1 or 2 at
room temperature, those of 5 were obtained by slow diffusion
of chlorobenzene into its o-dichlorobenzene solution. However,
in contrast to the cases for 1, 2, and 5, single crystals of 3 or
4 were obtained at room temperature by an interlayer diffusion
reaction process, which involves an o-dichlorobenzene solution
of (dppc)+(PF6)- being diffused into a chlorobenzene solution
consisting of C60 and M(PPh3)4 (M ) Pd, Pt). Each single
crystal of 1 (0.20 × 0.16 × 0.14 mm), 2 (0.25 × 0.20 × 0.10
mm), 3 (0.26 × 0.24 × 0.18 mm), 4 (0.24 × 0.20 × 0.16 mm),
or 5 (0.16 × 0.12 × 0.10 mm) was glued to a glass fiber and
mounted on a Bruker SMART 1000 automated diffractometer.
Data were collected at room temperature, using graphite-
monochromated Mo KR radiation (λ ) 0.710 73 Å) in the ω-2θ
scanning mode. An absorption correction was performed using
the SADABS method. The structures were solved by direct
Ack n ow led gm en t. We are grateful to the National
Natural Science Foundation of China (No. 20172026),
the State Key Laboratory of Organometallic Chemistry,
and the Research Fund for the Doctoral Program of
Higher Education of China for financial support of this
work.
Su p p or tin g In for m a tion Ava ila ble: CIF files giving all
crystal data, atomic coordinates and thermal parameters, and
bond lengths and angles for 1-5. This material is available
free of charge via the Internet at http://pubs.acs.org.
OM049667A