Synthesis of heterodinuclear (Carbene)platinum (or palladium) complex that gives μ-alkenyl-type complex by deprotonation

Article abstract of DOI:10.1021/om900421k

Heterodinuclear platinum (or palladium) complexes having a terminal carbene, (Ph₃P)Cl(Me_2- NHC)M-M′L′_n (M = Pt:M′L′ _n = Co(CO)₄ (1), Mn(CO) ₅ (2), MoCp(CO)₃ (3), FeCp(CO)₂ (4); M = Pd: M′L′_n = Co(CO)₄ (33), Mn(CO)₅ (34)) and (L)Cl{(PhCH₂)YC}Pt-M_'L_'., (WVn = Co(CO)₄, L = PMe₂Ph: Y = NPh₂ (5), OEt (6), OMe (7), OⁱPr (8); M′L′_n = Co(CO)₄, L = PPh₃: Y = OEt (9); M′L′n = Mn(CO)₅, L = PMe₂Ph: Y = OEt (10)), are synthesized by metathesis reactions of dichlorocarbene complexes with metalate Na⁺[M′L′ _n]^-. These complexes are characterized by NMR and IR spectroscopies and elemental analysis, and the molecular structures of 1, 2, and 6 are determined by X-ray structure analysis. Deprotonation of 6-10 with base gives heterodinuclear μ-alkoxystyrylplatinum-metal complexes, (L)(CO){μ-PhHC=YC}Pt-M′L′.,_n-1 (M′L′ _n-1 = Co(CO)₃, L=PMe₂Ph: Y = OEt (13), OMe (14), OⁱPr (15); M′L′^n-1 = Co(CO)₃, L = PPh₃: Y = OEt (16); M′L′.,_n-1 = Mn(CO)₄, L = PMe₂Ph: Y = OEt (12)), where the E isomer is thermodynamically stable. Z isomers of corresponding monomelic alkoxystyrylplatinum(II) complexes are found to be more stable than the corresponding E isomers. In contrast, both the dinuclear diphenylaminostyrylplatinum-cobalt complex and its mononuclear analogue favor the Z configuration.

Full text of DOI:10.1021/om900421k

5368 Organometallics 2009, 28, 5368–5381
DOI: 10.1021/om900421k
Synthesis of Heterodinuclear (Carbene)platinum (or palladium) Complex
That Gives μ-Alkenyl-Type Complex by Deprotonation
Shin-ichi Tanaka, Nobuyuki Komine, Masafumi Hirano, and
Sanshiro Komiya*
Department of Applied Chemistry, Graduate School of Engineering, Tokyo University of
Agriculture and Technology, 2-24-16 Nakacho, Koganei, Tokyo 184-8588, Japan
Received May 20, 2009
Heterodinuclear platinum (or palladium) complexes having a terminal carbene, (Ph3P)Cl(Me2-
NHC)M-M0L0n (M = Pt: M0L0n = Co(CO)4 (1), Mn(CO)5 (2), MoCp(CO)3 (3), FeCp(CO)2 (4);
M=Pd: M0L0n=Co(CO)4 (33), Mn(CO)5 (34)) and (L)Cl{(PhCH2)YC}Pt-M0L0n (M0L0n=Co(CO)4,
L=PMe2Ph: Y=NPh2 (5), OEt (6), OMe (7), OiPr (8); M0L0n=Co(CO)4, L=PPh3: Y=OEt (9);
M0L0n = Mn(CO)5, L = PMe2Ph: Y = OEt (10)), are synthesized by metathesis reactions of
dichlorocarbene complexes with metalate Naþ[M0L0n]-. These complexes are characterized by
NMR and IR spectroscopies and elemental analysis, and the molecular structures of 1, 2, and 6
are determined by X-ray structure analysis. Deprotonation of 6-10 with b0ase gives heterodinuclear
μ-alkoxystyrylplatinum-metal complexes, (L)(CO){μ-PhHCdYC}Pt-M0L n-1 (M0L0n-1=Co(CO)3,
L=PMe2Ph: Y=OEt (13), OMe (14), OiPr (15); M0L0n-1=Co(CO)3, L=PPh3: Y=OEt (16); M0L0n-1
=
Mn(CO)4, L=PMe2Ph: Y=OEt (12)), where the E isomer is thermodynamically stable. Z isomers
of corresponding monomeric alkoxystyrylplatinum(II) complexes are found to be more stable than
the corresponding E isomers. In contrast, both the dinuclear diphenylaminostyrylplatinum-cobalt
complex and its mononuclear analogue favor the Z configuration.
Introduction
since carbene complexes constitute a center of organometallic
reactions.3 As an extension of our work, we synthesized
new heterodinuclear complexes having a MdC double bond,
which is still relatively rare.4 One known example is trans-
[Pt(CNC6H11){C(OEt)(NHC6H11)}{MoCp(CO)3}2], reported
by Braunstein et al. by the metathesis reaction of cis-[PtCl2-
(CNC6H11){C(OEt)(NHC6H11)}] with Naþ[MoCp(CO)3]-.5
In this paper, we report the synthesis of Fischer-type hetero-
dinuclear (carbene)platinum (or palladium) complexes having
tertiary phosphine ligands, (Ph3P)Cl(Me2NHC)M-M0L0n
(M = Pt: M0L0n = Co(CO)4 (1), Mn(CO)5 (2), MoCp(CO)3
(3), FeCp(CO)2 (4); M=Pd: M0L0n=Co(CO)4 (33), Mn(CO)5
(34)) and (L)Cl{(PhCH2)YC}Pt-M0L0n (M0L0n = Co(CO)4,
L=PMe2Ph: Y=NPh2 (5), OEt (6), OMe (7), OiPr (8); M0L0n=
Co(CO)4, L=PPh3: Y=OEt (9); M0L0n=Mn(CO)5, L=PMe2-
Ph: Y =OEt (10)), by metathesis reactions of corresponding
dichloro (carbene)platinum complexes with metalates Naþ-
[M0L0n]-. Formation of heterodinuclear μ-(E)-alkenyl com-
plexes by deprotonation with a base is also described.
Heterodinuclear complexes have attracted much attention
due to a cooperative effect of the two different metals.1
We previously reported the synthesis of a series of heterodi-
nuclear complexes having both an M-M0 bond and an
M-C(or H) single bond, L2RM-M0L0n (M=Pt, Pd; M0 =
Mo, W, Mn, Re, Fe, Co; R=Me, Et, CH2CMe3, Ph, COMe,
COEt, COCH2CMe3, COPh, H; L2=cod, dppe, tmeda, bpy,
phen, Ph2PC2H4NEt2, Ph2PC2H4SMe, Ph2PC2H4CHdCH2;
L0=CO, Cp) as the simplest model for active intermediates in
bimetallic catalyses, some of which showed remarkable reac-
tivities and catalytic activities.2 Synthesis and reactions of
heterodinuclear complexes having a metal-carbon multiple
bond are also considered to be valuable subjects to study,
*To whom correspondence should be addressed. E mail: komiya@
cc.tuat.ac.jp.
(1) (a) Ritleng, V.; Chetcuti, M. J. Chem. Rev. 2007, 107, 797. (b)
Wheatley, N.; Kalck, P. Chem. Rev. 1999, 99, 3379.
(2) (a) Fukuoka, A.; Sadashima, T.; Sugiura, T.; Wu, X.; Mizuho, Y.;
Komiya, S. J. Organomet. Chem. 1994, 473, 139. (b) Fukuoka, A.;
Sadashima, T.; Endo, I.; Ohashi, N.; Kambara, Y.; Sugiura, T.; Miki, K.;
Kasai, N.; Komiya, S. Organometallics 1994, 13, 4033. (c) Komiya, S.;
Muroi, S.; Furuya, M.; Hirano, M. J. Am. Chem. Soc. 2000, 122, 170. (d)
Fukuoka, A.; Fukagawa, S.; Hirano, M.; Koga, N.; Komiya, S. Organome-
tallics 2001, 20, 2065. (e) Furuya, M.; Tsutsuminai, S.; Nagasawa, H.;
Komine, N.; Hirano, M.; Komiya, S. Chem. Commun. 2003, 2046. (f)
Tsutsuminai, S.; Komine, N.; Hirano, M.; Komiya, S. Organometallics 2003,
22, 4238. (g) Tsutsuminai, S.; Komine, N.; Hirano, M.; Komiya, S. Orga-
nometallics 2004, 23, 44. (h) Kuramoto, A.; Nakanishi, N.; Kawabata, T.;
Komine, N.; Hirano, M.; Komiya, S. Organometallics 2006, 25, 311. (i)
Tanaka, S.; Hoh, H.; Akahane, Y.; Tsutsuminai, S.; Komine, N.; Hirano, M.;
Komiya, S. J. Organomet. Chem. 2007, 692, 26.
(3) (a) Trnka, T. M.; Grubbs, R. H. Acc. Chem. Res. 2001, 34, 18. (b)
Schrock, R. R.; Hoveyda, A. H. Angew. Chem., Int. Ed. 2003, 42, 4592. (c)
Wu, Y. T.; Kurahashi, T.; Meijere, A. J. Organomet. Chem. 2005, 690, 5900.
(4) (a) Graham, T. W.; Van Gastel, F.; McDonald, R.; Cowie, M.
Organometallics 1999, 18, 2177. (b) Sterenberg, B. T.; McDonald, R.;
Cowie, M. Organometallics 1997, 16, 2297. (c) Breen, M. J.; Shulman, P.
M.; Geoffroy, G. L.; Rheingold, A. L.; Fultz, W. C. Organometallics 1984, 3,
782. (d) Fischer, E. O.; Offhaus, E.; Muller, J.; Nothe, D. Chem. Ber. 1972,
105, 3027. (e) Fischer, E. O.; Offhaus, E. Chem. Ber. 1969, 102, 2549.
(5) Braunstein, P.; Keller, E.; Vahrenkamp, H. J. Organomet. Chem.
1979, 165, 233.
r
pubs.acs.org/Organometallics
Published on Web 09/02/2009
2009 American Chemical Society

Article
Organometallics, Vol. 28, No. 18, 2009 5369
Results and Discussion
essentially square planar in both cases, where Co (or Mn) and
PPh3 are trans to each other. Coordination geometries of the
cobalt and manganese atoms are considered to be distorted
tetrahedral and distorted trigonal bipyramidal, respectively,
suggesting the actual metal valency of the d10-Co(-1) (or
d8-Mn(-1)) anion and d8-Pt(II). The Co (or Mn) moiety is
considered to bind to the platinum(II) cation, as both ligands at
Pt and Co (or Mn) avoid steric repulsion. Although one
carbonyl ligand C(22)-O(1) in 1 lies close to the platinum
Synthesis of Heterodinuclear Aminocarbene Complexes
(Ph3P)Cl(R2NHC)Pt-M0L0n. When cis-[PtCl2(PPh3)(CHN-
Me2)] was treated with 1.2-2.2 equiv of Naþ[M0L0n]- (M0L0n=
Co(CO)4, Mn(CO)5, MoCp(CO)3, FeCp(CO)2) in THF
at -20 °C, corresponding heterodinuclear dimethylamino-
carbene complexes (Ph3P)Cl(Me2NHC)Pt-M0L0n (M0L0n=
Co(CO)4 (1), Mn(CO)5 (2), MoCp(CO)3 (3), FeCp(CO)2 (4))
were obtained as yellow-orange crystals or powder in 58, 43,
40, and 61% yields, respectively (eq 1). Diphenylaminocar-
bene complex 5 was also prepared (eq 2).
˚
atom (Pt-C(22)=2.473(14) A), no strong bridging character
may be involved, since the Co-C(22)-O(1) angle was close
to 180°. IR spectra of 1 and 2 show strong ν(CO) bands
at ca. 1900-2000 cm-1, which are similar to the other dinuclear
complexes2 but slightly shifted to higher frequencies, and are
also slightly higher than the known metalate complexes such as
[PPN]þ[Co(CO)4]- (1886 cm-1) and [PPN]þ[Mn(CO)5]-
(1861, 1894 cm-1).8 These may be interpreted by lower
electron density of the Co(-1) (or Mn(-1)) moiety than
the corresponding metalate by the electron-withdrawing
Cl ligand at Pt(II).
Synthesis of Heterodinuclear Alkoxycarbene Complexes
(L)Cl{(PhCH2)(EtO)C}Pt-M0L0n. Metathesis reaction of
mononuclear alkoxycarbene complexes cis-[PtCl2(L){CY-
(CH2Ph)}] (L=PMe2Ph, PPh3; Y=OEt, OMe, OiPr), with
1 equiv of Naþ[M0L0n]- (M0L0n=Co(CO)4, Mn(CO)5) also
gave analogous heterodinuclear carbene complexes, (L)Cl-
{(PhCH2)YC}Pt-M0L0n (M0L0n = Co(CO)4, L = PMe2Ph:
Y=OEt (6), OMe (7), OiPr (8); M0L0n=Co(CO)4, L=PPh3:
Y=OEt (9); M0L0n=Mn(CO)5, L=PMe2Ph: Y=OEt (10))
Only monosubstituted products were obtained, even in
the presence of an excess amount of metalate used. The
results are in contrast to the formation of trinuclear iso-
nitrile analogues reported by Braunstein.5 This may be due
to the larger steric bulkiness of the PPh3 ligand than the
isonitrile, preventing coordination of two M0L0n moieties to
Pt. Selected NMR and IR data of 1-5 are summarized in
Tables 1 and 2. In the 1H NMR, two methyl groups in the
dimethylamino group are unequivalent, showing that they
are diastereotopic. This result suggests the restricted rota-
tion around the Pt-C and C-N bonds as previously
reported for cis-[PtCl2(PPh3)(CHNMe2)]6a and other sec-
ondary aminocarbene complexes.6b The methine proton at
the carbene carbon appears as a singlet at ca. δ 10. Mole-
cular structures of 1 and 2 were determined by X-ray
structure analysis. The crystallographic data and selected
bond distances and angles are summarized in Tables 3 and
1
(eq 3). In the H NMR spectra, both benzylic methylene
protons and ethoxy methylene protons are observed at
different chemical shifts, showing that they are also diaster-
eotopic (Table 2). Rotation around the Pt-C bond in
solution is also restricted.7 The X-ray structure analysis of
6 revealed a molecular structure in which the platinum
adopted a square-planar geometry, and Co and PMe2Ph lie
in a trans fashion (Figure 2, Table 4). The cobalt atom is
considered to have a distorted tetrahedral structure, showing
a similar electronic state of Pt and Co in the dinuclear
˚
aminocarbene complexes 1. The Pt-C (1.901(11) A) and
˚
Pt-Co (2.6404(16) A) distances are similar to those for
˚
1 C6H6 (1.970(14) and 2.662(2) A, respectively).
3
4, respectively, and ORTEP drawings are depicted in Fig-
˚
ure 1. The Pt-C bond distances (1.970(14) A (1 C6H6),
3
˚
1.956(16) A (2 2C6H6)) are significantly shorter than those
3
in analogous heterodinuclear methylplatinum complexes,
2d
˚
(dppe)MePt-Co(CO)4 (2.12(2) A)
Mn(CO)5 (2.131(8) A), but similar to those in the known
and (dppe)MePt-
2c
˚
mononuclear carbene complexes cis-[PtCl2(PPh3)(CHNMe2)]
(1.96(1) A),6a cis-[PtCl2(PMe2Ph){C(OEt)(CH2Ph)}] (1.920(9)
˚
7
A), and trans-[Pt(CNR){C(OEt)(NHC6H11)}{MoCp(CO)3}2]
˚
In contrast to the above reactions, when cis-[PtCl2-
(PMe2Ph){C(OEt)(CH2Ph)}] was treated with 1 equiv of
Naþ[MoCp(CO)3]-, unexpected μ-alkenyl-type complex
(PhMe2P)(CO){(E)-μ-PhHCd(EtO)C}Pt-MoCp(CO)2 ((E)-
11) was obtained in ca. 50% yield. The yield increased to 69%
when 2 equiv of Naþ[MoCp(CO)3]- was used (eq 4). In this
reaction, formation of an equimolar amount of MoHCp-
(CO)3 was confirmed by 1H NMR, suggesting that the
[MoCp(CO)3]- acted as a base to abstract a proton from the
carbene ligand formed (vide infra). At the same time one
5
˚
˚
(2.02(1) A). The Pt-Co (or -Mn) bond distances (2.662(2) A
˚
(1 C6H6), 2.729(2) A (2 2C6H6)) are similar to those of hetero-
3
3
dinuclear methylplatinum complexes (dppe)MePt-Co(CO)4
˚
˚
(2.676(2) A) and (dppe)MePt-Mn(CO)5 (2.795(2) A). The
estimated C-N bond lengths are relatively short, consistent
with their partial multiple-bond character, which may prevent
rotation of the C-N bond. The geometry at platinum was
(6) (a) Barefield, E. K.; Carrier, A. M.; Sepelak, D. J.; Van Derveer,
D. G. Organometallics 1982, 1, 103. (b) Christian, D. F.; Clark, H. C.;
Stepaniak, R. F. J. Organomet. Chem. 1976, 112, 227.
(7) Anderson, G. K.; Cross, R. J.; Manojlovic-Muir, L.; Muir, K. W.;
Wales, R. A. J. Chem. Soc., Dalton Trans. 1979, 684.
(8) Thompson, D. M.; Bengouth, M.; Baird, M. C. Organometallics
2002, 21, 4762.

5370 Organometallics, Vol. 28, No. 18, 2009
Tanaka et al.

Article
Organometallics, Vol. 28, No. 18, 2009 5371

5372 Organometallics, Vol. 28, No. 18, 2009
Tanaka et al.
Table 3. Crystallographic Data for (Ph3P)Cl(Me2NHC)Pt-Co(CO)4 (1), (Ph3P)Cl(Me2NHC)Pt-Mn(CO)5 (2), and
(PhMe2P)Cl{(PhCH2)(EtO)C}Pt-Co(CO)4 (6)a
1 C6H6
2 2C6H6
6
3
3
empirical formula
fw
C31H28ClCoNO4PPt
799.02
C38H34ClMnNO5PPt
901.15
C22H23ClCoO5PPt
687.87
cryst color, habit
cryst dimens
(mm ꢀ mm ꢀ mm)
cryst syst
yellow, needle
0.37 ꢀ 0.17 ꢀ 0.05
amber, prismatic
0.49 ꢀ 0.33 ꢀ 0.13
light orange, needle
0.50 ꢀ 0.10 ꢀ 0.08
monoclinic
C2/c (No. 15)
32.165(6)
9.543(7)
20.395(7)
triclinic
monoclinic
P21/n (No. 14)
9.935(4)
26.390(10)
9.775(5)
space group
˚
P1 (No. 2)
11.80(17)
16.91(7)
9.15(3)
a (A)
˚
b (A)
˚
c (A)
R (deg)
β (deg)
γ (deg)
95.6(5)
91.1(6)
96.0(9)
1806.3(283)
2
1.657
888.00
43.631
ω-2θ
55.7
total: 7171
unique: 6827 (Rint = 0.035)
Patterson methods
0.0800
0.2406
0.960
95.394(19)
108.42(4)
3
˚
V (A )
Z
6232.5(48)
8
1.703
3120.00
51.706
ω-2θ
54.9
total: 7256
unique: 7131 (Rint = 0.123)
Patterson methods
0.0628
2431.6(18)
4
1.879
1328.00
66.109
ω
55.0
total: 6716
unique: 5560 (Rint = 0.084)
direct methods
0.0473
0.1462
0.924
Dcalcd (g cm-3
F000
)
μ(Mo KR) (cm-1
scan type
)
2θmax (deg)
no. of reflns measd
structure solution
R1 (I > 2σ(I))b
wR2
goodness of fit indicator
c
0.1978
0.957
P
P
a
Diffractometer: Rigaku AFC7R; radiation: 0.71069 A; temperature: -73.0 °C (1 C6H6, 2 2C6H6) or -73.1 °C (6). b R1 = ||Fo| - |Fc||/ |Fo|.
˚
3
3
P
P
c wR2 = [ w(Fo2 - Fc2)2/ w(Fo2)2]1/2
.
carbonyl ligand on Mo also transferred to Pt to form stable
square-planar and piano-stool configurations.
at δ -1.9 (JPtH=2802 Hz) and δ -11.1 (JPtH=3126 Hz).
Such a diastereomeric mixture is considered to be formed by
different face-selected coordination of a prochiral CdC
double bond to the chiral Mo atom. Therefore this dynamic
behavior is interpreted by the facile dissociation and associa-
tion of the alkenyl group at Pt to the molybdenum center
(Scheme 1). On the contrary, heating to 80 °C caused
coalescence of two sets of diastereotopic protons to give
two second-order double quartets at δ 3.82 and 3.87 (JHH
=
Complex (E)-11 was characterized spectroscopically as
well as by preliminary X-ray structure analysis. An ORTEP
drawing of one of the two similar independent molecules is
shown in Figure 3. The structures of Pt and Mo are square-
planar and distorted three-leg piano-stool, respectively, and
the (E)-μ-alkenyl ligand links these metals. Preferential for-
mation of the E isomer is observed, probably due to steric
repulsion between phenyl and the Pt moiety attached to the
CdC double bond.
10, 7 Hz). At the same time, broad methyl signals of the
PMe2Ph ligand appeared as two equal doublets with 195Pt
satellites at δ 1.43 and 1.54 (JPH =10 Hz, JPtH =31 Hz),
showing these methyl groups are also diastereotopic.
Such diastereotopic nature of these protons even at 80 °C
suggests involvement of chirality at Pt and/or Mo
atoms even after dissociation of the CdC double bond
from Mo. This may be because of the restricted rotation
of the Pt-alkenyl bond, giving a diastereotopic environ-
ment of these protons as shown in Scheme 1. Alterna-
tively restricted site exchange between Cp and one of
the carbonyl ligands may also interpret this dynamic
behavior.
In contrast to the above result, reaction with 2 equiv of
tetracarbonylcobaltate gave only a dinuclear carbene com-
plex, whereas treatment of 2 equiv of pentacarbonyl mana-
ganate with the dicholocarbene complex afforded a 1:2 mix-
ture of heterodinuclear carbene complex 10 and μ-alkenyl
complex (PhMe2P)(CO){(E)-μ-PhHCd(EtO)C}Pt-Mn(CO)4
((E)-12). As expected, reaction of the isolated heterodinuclear
VT 1H and 31P{1H} NMR spectra of (E)-11 are shown in
Figure 4 and Table 5. The diastereotopic methylene protons
of the ethoxy group appear at δ 3.8 as one broad signal at
20 °C. On lowering the temperature, the signal gradually
broadened and finally separated into two pairs of ill-sepa-
rated double quartets (δ 4.02, 4.14 and δ 3.16, 3.50) in 1:0.7
ratio at -60 °C, which are assigned to the diastereotopic
geminal protons of two diastereomeric isomers of (E)-11.
The alkenyl proton signal also split into two peaks at δ 4.86
and 4.21 in the same ratio. A very broad phosphorus
resonance at 20 °C shows a similar change on cooling, and
at -60 °C two sharp singlets with 195Pt satellites are observed
Scheme 1. Face-Selected Interconversion in the Diastereomeric Pair of (E)-11

Article
Organometallics, Vol. 28, No. 18, 2009 5373
Table 4. Selected Bond Lengths and Angles for
(Ph3P)Cl(Me2NHC)Pt-Co(CO)4 (1),
(Ph3P)Cl(Me2NHC)Pt-Mn(CO)5 (2), and
(PhMe2P)Cl{(PhCH2)(EtO)C}Pt-Co(CO)4 (6)
[MoHCp(CO)3], 14.1 for [MnH(CO)5]).9 The cobalt anion is
much less basic, thus discouraging proton abstraction. The
reactivity difference between Mo and Mn anions in proton
abstraction could arise from the stability difference of the
products.
˚
Bond Lengths (A) for (Ph3P)Cl(Me2NHC)Pt-Co(CO)4 (1)
Deprotonation of (L)Cl{(PhCH2)(EtO)C}Pt-M0L0n by
Amine. As we discussed above, a μ-alkenyl-type complex
is considered to be formed by abstraction of a benzylic
proton of (L)Cl{(PhCH2)(EtO)C}Pt-M0L0n by a metalate
anion probably as a base. Therefore, we carried out the
reaction of the heterodinuclear carbene complex with
amine as an organic base. When 6 was reacted with NEt3
in CD2Cl2, the μ-alkenyl-type complex (PhMe2P)(CO)-
{μ-PhHCd(EtO)C}Pt-Co(CO)3 (13) was formed as an
E/Z (82:18) mixture, supporting the above proton abstrac-
tion mechanism (eq 5, Table 6). The assignment of E/Z
isomers was performed by the coupling constant of the
terminal alkenyl proton with 195Pt in 1H NMR in CD2Cl2
(Table 5).10 The alkenyl proton signal at δ 5.67 due to the Z
isomer ((Z)-13) couples with 195Pt (J=36 Hz), in which the
Pt and H atoms are in trans position to each other, whereas
the signal at δ 4.54 assignable to the E isomer ((E)-13) shows
no 195Pt satellites.
Pt(1)-Co(1)
Pt(1)-P(1)
2.662(2)
2.275(3)
1.262(19)
1.762(19)
1.794(16)
1.15(2)
Pt(1)-C(1)
Pt(1)-Cl(1)
Co(1)-C(22)
Co(1)-C(24)
C(22)-O(1)
C(24)-O(3)
1.970(14)
2.393(3)
1.721(19)
1.748(17)
1.23(2)
C(1)-N(1)
Co(1)-C(23)
Co(1)-C(25)
C(23)-O(2)
C(25)-O(4)
1.19(2)
1.14(2)
Bond Angles (deg) for (Ph3P)Cl(Me2NHC)Pt-Co(CO)4 (1)
Co(1)-Pt(1)-C(1)
C(1)-Pt(1)-P(1)
Co(1)-C(22)-O(1)
Co(1)-C(24)-O(3)
C(22)-Co(1)-C(23)
C(22)-Co(1)-C(25) 115.3(8)
C(23)-Co(1)-C(25) 101.7(8)
84.4(4)
93.6(4)
Co(1)-Pt(1)-Cl(1)
Cl(1)-Pt(1)-P(1)
92.80(9)
89.68(11)
177(2)
168.6(11) Co(1)-C(23)-O(2)
175.8(15) Co(1)-C(25)-O(4)
96.1(8)
177.0(16)
C(22)-Co(1)-C(24) 123.8(7)
C(23)-Co(1)-C(24) 104.2(9)
C(24)-Co(1)-C(25) 110.9(8)
˚
Bond Lengths (A) for (Ph3P)Cl(Me2NHC)Pt-Mn(CO)5 (2)
Pt(1)-Mn(1)
2.729(2) Pt(1)-C(1)
2.275(4) Pt(1)-Cl(1)
1.30(2) Mn(1)-C(22)
1.84(2) Mn(1)-C(24)
1.90(2) Mn(1)-C(26)
1.19(2) C(23)-O(2)
1.15(2) C(25)-O(4)
1.16(2)
1.956(16)
Pt(1)-P(1)
2.373(4)
1.760(15)
1.785(17)
1.813(17)
1.14(2)
C(1)-N(1)
Mn(1)-C(23)
Mn(1)-C(25)
C(22)-O(1)
C(24)-O(3)
C(26)-O(5)
1.11(2)
Bond Angles (deg) for (Ph3P)Cl(Me2NHC)Pt-Mn(CO)5 (2)
Mn(1)-Pt(1)-C(1)
C(1)-Pt(1)-P(1)
85.3(5)
89.9(5)
Mn(1)-Pt(1)-Cl(1)
Cl(1)-Pt(1)-P(1)
94.54(13)
89.40(15)
Mn(1)-C(22)-O(1) 168.6(19) Mn(1)-C(23)-O(2) 174.4(18)
Mn(1)-C(24)-O(3) 178.2(15) Mn(1)-C(25)-O(4) 174.4(18)
Mn(1)-C(26)-O(5) 177.0(16) C(22)-Mn(1)-C(23) 89.3(7)
Slow isomerization of (Z)-13 to (E)-13 was observed to
give a >95% E-rich mixture of 13 in 2 days at room
temperature. When PhCH2NH2 was used as a base in the
reaction with 6, the initial E/Z ratio (76:24) also increased to
95:5 in a day. This isomerization proceeded under dark in
the same rate, implying that the isomerization is not a
photoinduced reaction. The methoxy carbene complex 7
gave the μ-alkenyl-type complex 14, and the isomerization
was also observed. The E/Z ratio after the isomerization of
14 was approximately equal to that of 13. When the
isopropoxycarbene complex 8 and ethoxycarbene complex
having PPh3 ligand 9 were reacted with NEt3, the E isomer
was generated in E/Z = 92:8 and 91:9 ratio from the
beginning, and no further isomerization was observed. In
the case of the reaction of manganese complex 10 with
NEt3, only the E isomer was obtained. The E isomer is
considered to be thermodynamically more stable than the
Z isomer for the dinulcear μ-alkenyl-type complex, prob-
ably due to larger steric repulsion among ligands in the Z
isomer than the E isomer (Scheme 2). The fact that Pt-Mn
complex 12 consists of only the E isomer may reflect the
larger steric repulsion of the Mn(CO)4 unit compared to the
Co(CO)3 unit. The isomerization mechanism from Z to E is
not clear at present, but rotation of the C-C bond via
C(22)-Mn(1)-C(24) 112.8(9)
C(22)-Mn(1)-C(26) 142.6(9)
C(23)-Mn(1)-C(25) 171.6(8)
C(24)-Mn(1)-C(25) 85.6(8)
C(25)-Mn(1)-C(26) 90.7(7)
C(22)-Mn(1)-C(25) 91.9(7)
C(23)-Mn(1)-C(24) 86.2(8)
C(23)-Mn(1)-C(26) 93.4(7)
C(24)-Mn(1)-C(26) 104.6(8)
˚
Bond Lengths (A) for (PhMe2P)Cl{(PhCH2)(EtO)C}Pt-Co(CO)4 (6)
Pt(1)-Co(1)
Pt(1)-P(1)
2.6404(16) Pt(1)-C(1)
2.276(2) Pt(1)-Cl(1)
1.901(11)
2.386(3)
1.776(16)
1.754(12)
1.150(19)
1.176(15)
C(1)-O(1)
1.312(17) Co(1)-C(19)
1.780(16) Co(1)-C(21)
1.783(13) C(19)-O(2)
Co(1)-C(20)
Co(1)-C(22)
C(20)-O(3)
C(22)-O(5)
1.16(2)
1.169(16)
C(21)-O(4)
Bond Angles (deg) for (PhMe2P)Cl{(PhCH2)(EtO)C}Pt-Co(CO)4 (6)
Co(1)-Pt(1)-C(1)
C(1)-Pt(1)-P(1)
Co(1)-C(19)-O(2) 174.6(12)
Co(1)-C(21)-O(4) 177.8(13)
C(19)-Co(1)-C(20) 128.8(6)
C(19)-Co(1)-C(22) 109.7(7)
C(20)-Co(1)-C(22) 111.6(6)
83.3(3)
97.9(3)
Co(1)-Pt(1)-Cl(1)
Cl(1)-Pt(1)-P(1)
Co(1)-C(20)-O(3) 173.3(11)
Co(1)-C(22)-O(5) 179.1(13)
C(19)-Co(1)-C(21) 99.3(6)
C(20)-Co(1)-C(21) 98.7(6)
C(21)-Co(1)-C(22) 104.0(5)
92.48(8)
86.58(10)
(carbene)platinum-manganese complex 10 with excess man-
ganate cleanly gave μ-alkenyl complex (E)-12, but (carbene)-
platinum-cobalt complex 6 did not react with excess metalate.
From these results, the proton abstraction ability is considered
to be in the order [MoCp(CO)3]->[Mn(CO)5]-.[Co(CO)4]-.
The trend may partially reflect the difference of pKa values of
these hydrides in acetonitrile (8.3 for [CoH(CO)4], 13.9 for
(9) Tilset, M.; Parker, V. D. J. Am. Chem. Soc. 1989, 111, 6711.
(10) (a) Mann, B. E.; Shaw, B. L.; Tucker, N. I. J. Chem. Soc. A 1971,
2667. (b) Rajaram, J.; Pearson, R. G.; Ibers, J. A. J. Am. Chem. Soc. 1974,
96, 2103.

5374 Organometallics, Vol. 28, No. 18, 2009
Tanaka et al.
Figure 1. ORTEP drawings of (Ph3P)Cl(Me2NHC)Pt-M0L0n (M0L0n = Co(CO)4 (1), Mn(CO)5 (2)). All hydrogen atoms and solvent
are omitted for clarity. Ellipsoids represent 50% probability.
Figure 2. ORTEP drawing of (PhMe2P)Cl{(PhCH2)(EtO)C}-
Pt-Co(CO)4 (6). All hydrogen atoms are omitted for clarity.
Ellipsoids represent 50% probability.
Figure 3. ORTEP drawing of (PhMe2P)(CO){(E)-μ-PhHCd
(EtO)C}Pt-MoCp(CO)2 ((E)-11). One of two similar indepen-
dent molecules is shown. All hydrogen atoms are omitted for
clarity. Ellipsoids represent 50% probability.
possible zwitterionic intermediates by resonance with an
oxonium or platinum cation as shown in Scheme 3 may
interpret the process.
It is of interest to compare the above E selectivity with the
corresponding mononuclear analogue. Mononuclear alkoxy-
styryl complexes trans-[PtClL2{CYdCHPh}] (L = PMe2Ph:
Y=OEt (23), OMe (24), OiPr (25); L=PPh3, Y=OEt (26))
were prepared by the reaction of the mononuclear carbene
complexes cis-[PtCl2L{CY(CH2Ph)}] with triethylamine fol-
lowing treatment of 1 equiv of phosphine ligand (eq 6, Table 7).
In these reactions uncharacterized alkenyl complexes
(18-21)11 were initially formed, but they readily gave alkenyl
complexes 23-26 by treatment with PMe2Ph at room tem-
perature. Although initial E/Z ratios of 23-25 were different
from each other, Z isomers gradually became the major
product by isomerization in all cases. Complex 26, having
PPh3, consisted of a mixture of Z-rich isomers from the
beginning, and no further isomerization was observed. The
Scheme 2. Difference of Steric Environment
Scheme 3. Possible Mechanism of Isomerization
(11) The complex is tentatively assigned as a mixture of dimeric (E)-
and (Z)-alkenylplatinum complexes by NMR (see Experimental
Section).

Article
Organometallics, Vol. 28, No. 18, 2009 5375
Figure 4. Variable-temperature 1H and 31P{1H} NMR spectra of (PhMe2P)(CO){(E)-μ-PhHCd(EtO)C}Pt-MoCp(CO)2 ((E)-11).
result is unexpected, since the E isomer is generally believed to
be more stable than the Z isomer for steric reasons.12 A higher
thermodynamic stability of the Z isomer of the monomeric
styrylplatinum complex is also found in the reaction of the
heterodinuclear (E)-styryl complex with excess dimethylphe-
nylphosphine. When in situ prepared complex 13 (E/Z=79:21)
was treated with 1 equiv of PMe2Ph, a ligand exchange reaction
took place to give a dinuclear bis(phosphine) complex,
cis-(PhMe2P)2{μ-PhHCd(EtO)C}Pt-Co(CO)3 (28), with
generation of an equimolar amount of CO (eq 7). Further
addition of excess PMe2Ph led to heterolytic Pt-Co bond
cleavage to give a cationic alkenyl complex, [Pt(PMe2Ph)3-
{C(OEt)dCHPh}]þ[Co(PMe2Ph)n(CO)m]- (29). The initial
E/Z ratio (E/Z=78:22) of 29 was almost the same as the E/Z
ratio of 13. However slow isomerization of (E)-29 to (Z)-29
took place to give a Z-rich (E/Z = 9:91) mixture in two
days. These results indicate that the Z isomer is thermodyna-
mically stable for monomeric alkoxystyrylplatinum(II) com-
plexes. Such preferential formation of a Z isomer of an
analogous alkenyl complex, trans-[PtMe(PPh3)2{C(OCH2-
CH2Cl)dCH(p-tolyl)}], was known, although no details were
described.13
(12) (a) Amatore, C.; Bensalem, S.; Ghalem, S.; Jutand, A. J.
Organomet. Chem. 2004, 689, 4642. (b) Chatgilialoglu, C.; Ballestri, M.;
Ferreri, C.; Vecchi, D. J. Org. Chem. 1995, 60, 3826.
(13) Belluco, U.; Bertani, R.; Fornasiero, S.; Michelin, R. A.; Moz-
zon, M. Inorg. Chim. Acta 1998, 275-276, 515.
Agostic interaction of the ortho proton of the styryl group
with Pt is expected in these Z isomers. The 1H NMR
chemical shift of the interacting proton with square-planar

5376 Organometallics, Vol. 28, No. 18, 2009
Tanaka et al.

Article
Organometallics, Vol. 28, No. 18, 2009 5377
Table 6. Formation of μ-Alkenyl-Type Complexes by Deproto-
nation of Heterodinuclear Carbene Complexes
substrate amine
time (h)
conversion product yield
(%) (%)
E:Z
6
NEt3
0.1
92 13
100
100
82 13
85 82:18
99 83:17
95 96:4
54 76:24
94 76:24
94 95:5
100 81:19
100 85:15
98 95:5
99 92:8
99 92:8
99 92:8
96 91:9
100 91:9
100 91:9
83 100:0
100 100:0
100 100:0
0
5
55
6
PhCH2NH2
NEt3
0.3
2
29
100
100
7
0.1
100 14
100
100
5
53
8
NEt3
0.1
100 15
100
100
5
24
9
NEt3
0.1
97 16
100
100
Figure 5. Structure of trans-[PtCl(PH3)2{C(OMe)dCHPh}] es-
timated by DFT calculation.
1
30
10
5
NEt3
0.1
1
86 12
100
100
Table 7. E/Z Ratio of Mononuclear Alkenyl Complexes
5
0.1
complex
time (h)
yield (%)
E/Z
NEt3
0
26
17
18
98
26
95
0:100
0:100
23
0.1
75
0.1
80
0.2
70
0.1
76
85
85
99
100
83
79
79
92
93
96
66:34
21:79
46:54
18:82
70:30
21:79
12:88
13:87
0:100
0:100
100
24
25
26
27
Pt(II) is known to be used as an indicator of the agostic
interaction, although the value of the 195Pt satellites is better
direct evidence. Pregosin previously reported that the closer
position of a certain proton above the square-planar Pt(II)
metal results in lower field shift, but sometimes without 195Pt
satellites.14 In the present case, the chemical shift of the ortho
proton of the (Z)-ethoxystyrylplatinum complex (Z)-13 is
0.7-0.8 ppm lower than that of free (E)-β-ethoxystyrene,
whereas the ortho proton of (E)-ethoxystyrylplatinum (E)-13
is shifted to higher field by 0.24 ppm than that of free (Z)-β-
ethoxystyrene.15 This result suggests that the mononuclear
(Z)-R-ethoxystyryl complex intrinsically has an interaction
with Pt, but the E isomer does not. Although the reason for
the unusual Z-preferred formation for the alkoxystyryl-
platinum(II) complex is not well understood at present, we
believe that the alkoxystyrylplatinum(II) complex has an
intrinsic agnostic interaction with one of the ortho protons of
the styryl group, which forces the Z structure.
0.1
21
Deprotonation of diphenylaminocarbene complex 5 with
NEt3 gave (Z)-diphenylaminostyrylplatinum-cobalt com-
plex 17, which did not isomerize to the E isomer (eq 5,
Table 6). The reaction of the corresponding mononuclear
complex with PMe2Ph and NEt3 also gave only the Z
isomer of diphenylaminostyrylplatinum complex 27 (eq 6,
Table 7). In this case, the stability of the Z isomer may
be mainly due to effective steric hindrance between NPh2
and Ph substitutents across the CdC double bond in
addition to an agnostic interaction of the ortho hydrogen
with Pt.
Reaction of (Ph3P)Cl(Me2NHC)Pt-M0L0n with Tertiary
Phosphine Ligand. When 1 and 2 were treated with an equi-
molar amount of PPh3 in acetone at room temperature, smooth
heterolytic cleavage of the metal-metal bond took þplace to
give ionic complexes trans-[PtCl(PPh3)2(CHNMe2)] [M0L0n]
(M0L0n=Co(CO)4 (30), Mn(CO)5 (31)) (eq 8).
In order to understand the reason for the higher stability of
(Z)-ethoxystyrylplatinum(II), the structures of both Z and
E isomers of trans-[PtCl(PH3)2(C(OMe)dCHPh)] were esti-
mated by DFT calculation, as shown in Figure 5. The phenyl
group is slightly twisted from the CdC plane by 27.77° in the
Z isomer as if one of the ortho hydrogens makes direct close
˚
contact with Pt (o-H Pt=2.723 A), whereas both the CdC
3 3 3
plane and phenyl ring are completely placed in the
same plane due to a resonance between phenyl and the
CdC bond for the E isomer (dihedral angle=4.04°). These
results probably indicate a weak but significant interaction
of the ortho hydrogen with Pt in the Z isomer, although
no bonding orbital interaction of the ortho hydrogen with
Pt was found.
Such ionization reactions were reported for other heterodi-
nuclear alkylplatinum complexes.2b,2f 1H NMR of 30 showed
(14) Albinati, A.; Pregosin, P. S.; Wombacher, F. Inorg. Chem. 1990,
29, 1812.
a singlet due to carbene proton resonance at δ 10.4 (brs, JPtH
=
20 Hz) (Table 1). 31P{1H} NMR shows a singlet at δ 19.0 (s,
JPtP=2633 Hz), indicating two triphenylphosphine ligands are
located in a trans fashion. The CO stretching absorption band
(1883 cm-1) was almost the same as that of [PPN]þ[Co(CO)4]-
(1886 cm-1).8 The molar electric conductivity of 30 was found
to be very large (Λ (THF, rt)=18 S cm2 mol-1), supporting its
(15) 1H NMR (rt, CD2Cl2) of (E)-β-ethoxystyrene:23a δ 1.35 (t, JHH
=
7 Hz, OCH2CH3, 3H), 3.92 (q, JHH=7 Hz, OCH2, 2H), 5.85 (d, JHH=13 Hz,
dCH, 1H), 7.05 (d, JHH=13 Hz, dCH, 1H), 7.1-7.2 (m, p-Ph, 1H), 7.2-7.3
1
(m, o- and m-Ph, 4H). H NMR (rt, CD2Cl2) of (Z)-β-ethoxystyrene:23b
δ
1.38 (t, JHH=7 Hz, OCH2CH3, 3H), 4.01 (q, JHH=7 Hz, OCH2, 2H), 5.23 (d,
JHH=7 Hz, dCH, 1H), 6.27 (d, JHH=7 Hz, dCH, 1H), 7.15 (t, JHH=7 Hz, p-
Ph, 1H), 7.30 (t, JHH=7 Hz, m-Ph, 2H), 7.60 (d, JHH=7 Hz, o-Ph, 2H).

5378 Organometallics, Vol. 28, No. 18, 2009
Tanaka et al.
ionic structure. When 1 was reacted with 1,2-bis(diphenylphos-
phino)ethane (dppe), ligand displacement also took place to
give an analogous ionic carbene complex, [PtCl(dppe)(CHN-
Me2)]þ[Co(CO)4]- (32) (eq 9).
with appropriate drying agents before use (C6D6, toluene-d8,
and THF-d8 from Na; CD2Cl2 and CDCl3 from P2O5; acetone-
d6 from Drierite). [Pt(μ-Cl)Cl(PMe2Ph)]2,16,17 [Pt(μ-Cl)Cl-
(PPh3)]2,17 cis-[PtCl2(PPh3)(CHNMe2)],6a cis-[PtCl2(PMe2Ph)-
{C(OEt)(CH2Ph)}],7 cis-[PtCl2(PMe2Ph){C(OMe)(CH2Ph)}],7
cis-[PdCl2(PPh3)(CHNMe2)],18 cis-[PtCl2(PMe2Ph){C(NPh2)-
(CH2Ph)}],19 Naþ[Co(CO)4]-,20 Naþ[Mn(CO)5]-,21 Naþ[Mo-
Cp(CO)3]-,22 and Naþ[FeCp(CO)2]-22 were prepared by the
literature methods with minor modifications. Authentic samples
of (E)- and (Z)-β-ethoxystyrene were also synthesized by the
literature methods.23 NMR spectra were recorded on a JEOL
1
LA-300 (300.4 MHz for H, 121.6 MHz for 31P) or a JEOL
1
ECX-400P (399.8 MHz for H, 161.8 MHz for 31P) spectro-
Attempted Preparation of Heterodinuclear (Carbene)palla-
dium-Metal Complexes (Ph3P)Cl(Me2NHC)Pd-M0L0n. To
expand the scope of the synthesis, we conducted the reaction
of analogous palladium carbene complex cis-[PdCl2(PPh3)-
(CHNMe2)] with 1 equiv of Naþ[M0L0n]-. As a result,
expected heterodinuclear complexes (Ph3P)Cl(Me2NHC)-
Pd-M0L0n (M0L0n = Co(CO)4 (33), Mn(CO)5 (34)) were
formed, although ioþnic bis(phosphine) complexes trans-[PdCl-
(PPh3)2(CHNMe2)] [M0L0n]- (M0L0n = Co(CO)4 (35), Mn-
(CO)5 (36)) were always contaminated (eq 10), preventing
isolation of pure compounds.
meter. Chemical shifts were reported in ppm downfield from
TMS for 1H and from 85% H3PO4 in D2O for 31P. IR spectra
were recorded on a JASCO FT/IR-410 or JASCO FT/IR-4100
spectrometer using KBr disks. Elemental analyses were carried
out with a Perkin-Elmer 2400 series II CHN analyzer. Gas
chromatography was carried out using a Shimadzu GC-8A
instrument. Molar electric conductivity was measured on a
TOA Conduct Meter CM 7B.
Synthesis of Mononuclear (Carbene)platinum Complexes. cis-
[PtCl2(PMe2Ph){C(OiPr)(CH2Ph)}]. This was synthesized by an
analogous method to that for cis-[PtCl2(PMe2Ph){C(OEt)-
(CH2Ph)}] and cis-[PtCl2(PMe2Ph){C(OMe)(CH2Ph)}].7 [Pt(μ-
Cl)Cl(PMe2Ph)]2 (96.6 mg, 0.120 mmol) was dissolved in CHCl3
(13 mL), and then 2-propanol (0.8 mL, 10 mmol) and phenyla-
cetylene (41 μL, 0.37 mmol) were added to the solution. The
solution was refluxed for 3 h. All the volatile matter was
evaporated, and the resultant solid was reprecipitated from
CH2Cl2/hexane to give a brown solid. Yield: 85% (114.7 mg,
1
0.2025 mmol). H NMR (rt, CDCl3): δ 1.31 (d, JHH = 6 Hz,
OCH(CH3)2, 3H), 1.62 (d, JPH=11 Hz, JPtH=45 Hz, PCH3, 3H),
1.64 (d, JHH =6 Hz, OCH(CH3)2, 3H), 1.71 (d, JPH =11 Hz,
The NMR and IR data of these complexes are summarized
in Table 1. Addition of PPh3 to the mixture increased the
signal intensity of 35 (or 36).
JPtH=45 Hz, PCH3, 3H), 4.01 (d, JHH=17 Hz, CH2Ph, 1H), 4.12
(d, JHH=17 Hz, CH2Ph, 1H), 6.41 (sep, JHH=6 Hz, OCH, 1H).
31P{1H} NMR (rt, CDCl3): δ -17.3 (s, JPtP=3770 Hz).
Summary
cis-[PtCl2(PPh3){C(OEt)(CH2Ph)}]. This was prepared ana-
logously to that above using [Pt(μ-Cl)Cl(PPh3)]2 (62.9 mg,
0.0595 mmol), ethanol (0.6 mL, 10 mmol), and phenylacetylene
(33 μL, 0.30 mmol). The resultant solid was recrystallized from
CH2Cl2/hexane to give pale yellow crystals. Yield: 30%
(21.2 mg, 0.0362 mmol). 1H NMR (rt, CDCl3): δ 1.43 (t,
The metathesis reactions of (carbene)platinum complexes
having chloro ligands with Naþ[M0L0n]- gave heterodinuclear
(carbene)platinum complexes (Ph3P)Cl(Me2NHC)Pt-M0L0n
(M0L0n=Co(CO)4 (1), Mn(CO)5 (2), MoCp(CO)3 (3), FeCp-
(CO)2 (4)) and (L)Cl{(PhCH2)YC}Pt-M0L0n (M0L0n = Co-
(CO)4, L=PMe2Ph: Y=NPh2 (5), OEt (6), OMe(7), OiPr (8);
M0L0n=Co(CO)4, L=PPh3: Y=OEt (9); M0L0n=Mn(CO)5,
L = PMe2Ph: Y = OEt (10)). On the other hand, cis-[Pt-
Cl2(PMe2Ph){C(OEt)(CH2Ph)}] reacted with Naþ[MoCp-
(CO)3]- to give unexpected μ-alkenyl-type Pt-Mo complex
(E)-11. Heterodinuclear μ-alkyenylplatinum-metal complexes
12-17 were also prepared by deprotonation of 5-10 by
metalate or amine as a base. Heterodinuclear alkoxystyryl
complex favored the E form, although the corresponding
mononuclear complex consisted of a Z isomer. Treatments of
1 and 2 with PPh3 or dppe caused heterolytic cleavage of the
Pt-M bond to give cationic (carbene)platinum complexes
30-32. The metathesis reaction can also be applied to prepare
heterodinuclear (carbene)palladium complexes 33 and 34,
although contamination of the corresponding ionic bispho-
sphine complexes was involved.
J
HH =7 Hz, OCH2CH3, 3H), 3.31 (d, JHH =19 Hz, CH2Ph,
1H), 3.97 (d, JHH=19 Hz, CH2Ph, 1H), 4.91 (dq, JHH=10, 7 Hz,
OCH2, 1H), 5.76 (dq, JHH = 10, 7 Hz, OCH2, 1H). 31P{1H}
NMR (rt, CDCl3): δ 9.3 (s, JPtP=4019 Hz).
Synthesis of Heterodinucler (Carbene)platinum (or palladium)
Complexes (1-10, 33, 34). A typical procedure for (Ph3P)Cl-
(Me2NHC)Pt-Co(CO)4 C6H6 (1 C6H6) is given. Naþ[Co-
3
3
(CO)4]- (70.9 mg, 0.366 mmol) was dissolved in THF (18 mL).
The solution was added to a THF (22 mL) solution of cis-[PtCl2-
(PPh3)(CHNMe2)] (176.2 mg, 0.3010 mmol) at -70 °C. Then the
mixture was stirred for 3 h at -20 °C to give a yellow solution with
a little white suspension. All the volatile matter was evaporated,
and the resultant solid was extracted with benzene (5 mL ꢀ 6).
After removal of benzene in a vacuum, the residual orange solid
(16) Baratta, W.; Pregosin, P. S. Inorg. Chim. Acta 1993, 209, 85.
(17) Boag, N. M.; Ravetz, M. S. J. Chem. Soc., Dalton Trans. 1995,
3473.
(18) McCrindle, R.; McAlees, A. J.; Zang, E.; Ferguson, G. Acta
Crystallogr. 2000, C56, e132.
(19) Cross, R. J.; Davidson, M. F.; Rocamora, M. J. Chem. Soc.,
Dalton Trans. 1988, 1147.
Experimental Section
(20) Edgell, W. F.; Lyford, J. Inorg. Chem. 1970, 9, 1932.
(21) Hieber, W.; Faulhaber, G.; Theubert, F. Z. Anorg. Allg. Chem.
1962, 314, 125.
(22) Piper, T. S.; Wilkinson, G. J. Inorg. Nucl. Chem. 1956, 3, 104.
(23) (a) (E isomer) Park, H.; Kim, D. H.; Yoo, M. S.; Park, M.; Jew,
S. Tetrahedron Lett. 2000, 41, 4579. (b) (Z isomer) Baldwin, J. E.; Walker,
L. E. J. Org. Chem. 1966, 31, 3985.
All manipulations were carried out under a dry nitrogen or
argon atmosphere using standard Schlenk techniques. Solvents
were dried over and distilled from appropriate drying agents
under N2: hexane, benzene, toluene, diethyl ether, and THF
from Na/benzophenone ketyl; CH2Cl2 from P2O5; acetone from
Drierite. NMR solvents were commercially obtained and dried

Article
Organometallics, Vol. 28, No. 18, 2009 5379
was dissolved in a mixture of benzene and THF. The solution was
then concentrated, and hexane was added to give yellow needles of
1 C6H6. Yield: 58% (139.2 mg, 0.1742 mmol). Anal. Calcd for
solution of cis-[PtCl2(PMe2Ph){C(OEt)(CH2Ph)] (151.6 mg,
0.2745 mmol) at -70 °C. Then the mixture was stirred for 3 h
at -20 °C to give an orange solution with a small amount of
white precipitates. Solvent was evaporated, and the resultant
solid was extracted with benzene (5 mL ꢀ 5). After removal of all
volatile matters in a vacuum, the residual orange solid was
recrystallized from THF/hexane to give orange crystals of
(PhMe2P)(CO){(E)-μ-PhHCd(EtO)C}Pt-MoCp(CO)2 ((E)-11).
Yield: 69% (136.8 mg, 0.1886 mmol). Anal. Calcd for
C26H27MoO4PPt: C, 43.04; H, 3.75. Found: C, 43.79; H, 3.98.
Reaction of (L)Cl{(PhCH2)(EtO)C}Pt-M0L0n (5-10) with
Triethylamine. A typical procedure is given. (PhMe2P)Cl-
{(PhCH2)(EtO)C}Pt-Co(CO)4 (6) (7.0 mg, 0.010 mmol) was
dissolved in CD2Cl2. Then dibenzyl (0.0031 mmol) in CD2Cl2
was added as an internal standard. After addition of NEt3
(0.010 mmol), NMR spectra were periodically measured at
30 °C to monitor the reaction.
Reaction of in Situ Prepared Alkoxystyrylplatinum(II) Com-
plex with Tertiary Phosphine Ligand. A typical procedure
was given. Ethoxystyrylplatinum(II) complex was in situ pre-
pared by the reaction of cis-[PtCl2(PMe2Ph){C(OEt)(CH2Ph)}]
with NEt3. cis-[PtCl2(PMe2Ph){C(OEt)(CH2Ph)}] (7.8 mg,
0.014 mmol) was dissolved in CD2Cl2, and then 1,2-dimethox-
yethane (0.0096 mmol) was added as an internal standard.
NMR analysis immediately after addition of NEt3 (0.014 mmol)
revealed the formation of a mixture of dimeric (E)- and (Z)-
alkenyl complexes (18) (conv. 100%, yield 56% (E), 29% (Z)),
although the isolation and its full characterization were unsuc-
cessful. Ratio of the coordinated PMe2Ph and the alkenyl group
was 1:1, suggesting a dimeric structure rather than a putative
three-coordinate structure for 18, [Pt(μ-Cl)(PMe2Ph){C(OEt)d
CHPh}]2. 1H NMR (rt, CD2Cl2): δ 4.08 (brm, OCH2 of (E)-18 or
(Z)-18, 1H), 4.19 (brm, OCH2 of (E)-18 or (Z)-18, 1H), 4.47
(brm, OCH2 of (E)-18 or (Z)-18, 2H), 5.06 (s, JPtH = 36 Hz,
CHPh of (E)-18, 1H), 5.96 (brs, JPtH=76 Hz, CHPh of (Z)-18,
1H). 31P{1H} NMR (rt, CD2Cl2): δ -16.6 (s, JPtP=4596 Hz, (E)-
18 or (Z)-18), -17.9 (s, JPtP=4600 Hz, (E)-18 or (Z)-18).
The following complexes were also prepared in situ by the
reaction of cis-[PtCl2(L){CY(CH2Ph)}] with NEt3.
3
C31H28ClCoNO4PPt: C, 46.60; H, 3.53; N, 1.75. Found: C, 46.67;
H, 3.74; N, 1.77. Molar electric conductivity Λ (THF, rt): 0.030 S
cm2 mol-1. 1Hand31P{1H} NMR and IR data are given in Table 1.
1
Complexes 2-10, 33, and 34 were synthesized similarly. H
and 31P{1H} NMR and IR data of 2-10, 33, and 34 are
summarized in Tables 1 and 2. Following are yield, analytical
data, and some physical data. Complexes 3-5, 7-10, 33, and 34
were characterized spectroscopically.
(Ph3P)Cl(Me2NHC)Pt-Mn(CO)5 2C6H6 (2 2C6H6). Naþ-
þ3
3
[Mn(CO)5]- was used instead of Na [Co(CO)4]-. Orange crys-
tals. Yield: 43%. Anal. Calcd for C38H34ClMnNO5PPt: C,
50.65; H, 3.80; N, 1.55. Found: C, 50.10; H, 4.15; N, 1.56. Molar
electric conductivity Λ (THF, rt): 0.059 S cm2 mol-1
.
(Ph3P)Cl(Me2NHC)Pt-MoCp(CO)3 (3). Naþ[MoCp(CO)3]-
was used instead of Naþ[Co(CO)4]-. CH2Cl2 was used for extrac-
tion instead of benzene. Yellow microcrystals from CH2Cl2/
hexane. Yield: 40%.
(Ph3P)Cl(Me2NHC)Pt-FeCp(CO)2 (4). Naþ[FeCp(CO)2]-
was used instead of Naþ[Co(CO)4]-. Orange powder. Yield:
61%. Recrystallization from benzene/hexane gave dark brown
crystals, with low yield (6%).
(PhMe2P)Cl{(PhCH2)(Ph2N)C}Pt-Co(CO)4 (5). cis-[PtCl2-
(PMe2Ph){C(NPh2)(CH2Ph)] was used instead of cis-[PtCl2-
(PPh3)(CHNMe2)]. The resultant brown solid after removal of
benzene contained impurities. The impurities were deposited
from benzene/hexane to give a brown solid of 5. Yield: 31%.
(PhMe2P)Cl{(PhCH2)(EtO)C}Pt-Co(CO)4 (6). cis-[PtCl2-
(PMe2Ph){C(OEt)(CH2Ph)] was used instead of cis-[PtCl2-
(PPh3)(CHNMe2)]. CH2Cl2 was used for extraction instead of
benzene. Orange crystals from CD2Cl2/hexane. Yield: 58%.
Anal. Calcd for C22H23ClCoO5PPt: C, 38.41; H, 3.37. Found:
C, 38.37; H, 3.51.
(PhMe2P)Cl{(PhCH2)(MeO)C}Pt-Co(CO)4 (7). cis-[PtCl2-
(PMe2Ph){C(OMe)(CH2Ph)] was used instead of cis-[PtCl2-
(PPh3)(CHNMe2)]. CH2Cl2 was used for extraction instead of
benzene. Yellow-brown solid. Yield: 76%.
(PhMe2P)Cl{(PhCH2)(iPrO)C}Pt-Co(CO)4 (8). cis-[PtCl2-
(PMe2Ph){C(OiPr)(CH2Ph)] was used instead of cis-[PtCl2-
(PPh3)(CHNMe2)]. CH2Cl2 was used for extraction instead of
benzene. Orange crystals from THF/hexane. Yield: 27%.
(Ph3P)Cl{(PhCH2)(EtO)C}Pt-Co(CO)4 (9). cis-[PtCl2(PPh3)-
{C(OEt)(CH2Ph)] was used instead of cis-[PtCl2(PPh3)(CHN-
Me2)]. Yellow powder. Yield: 66%.
(PhMe2P)Cl{(PhCH2)(EtO)C}Pt-Mn(CO)5 (10). cis-[PtCl2-
(PMe2Ph){C(OEt)(CH2Ph)] and Naþ[Mn(CO)5]- were used
instead of cis-[PtCl2(PPh3)(CHNMe2)] and Naþ[Co(CO)4]-,
respectively. Dark brown oil. Yield: 92%. The amount of Naþ-
[Mn(CO)5]- used should be exactly 1 equiv to platinum. When
excess Naþ[Mn(CO)5]- was used, 12 was contaminated.
(Ph3P)Cl(Me2NHC)Pd-Co(CO)4 (33). Reaction of cis-
[PdCl2(PPh3)(CHNMe2)] with Naþ[Co(CO)4]- was conducted
in THF for 0.7 h at -50 to -70 °C. After the reaction, excess
hexane was added to precipitate a dark brown solid, and then
the solid was extracted with toluene. The extract was directly
added to cold hexane to precipitate the product. A brown solid
containing a mixture of 33 and 35 was obtained. Yield: 12%
(33), 2% (35).
(Ph3P)Cl(Me2NHC)Pd-Mn(CO)5 (34). The reaction of cis-
[PdCl2(PPh3)(CHNMe2)] with Naþ[Mn(CO)5]- was conducted
in THF at -40 °C for 0.3 h. After the reaction, solvent was
evaporated at -30 °C and the residue was then extracted with
toluene. Addition of excess hexane gave a brown solid contain-
ing a mixture of 34 and 36. Yield: 44% (34), 20% (36).
Synthesis of Heterodinuclear μ-Alkoxystyrylplatinum-
Molybdenum Complex (PhMe2P)(CO){(E)-μ-PhHCd(EtO)C}-
Pt-MoCp(CO)2 ((E)-11). Naþ[MoCp(CO)3]- (148.1 mg,
0.5525 mmol) in THF (9 mL) was added to a THF (20 mL)
[Pt(μ-Cl)(PMe2Ph){C(OMe)dCHPh}]2 (19): 1H NMR (rt,
CD2Cl2): δ 3.74 (s, OCH3 of (E)-19 or (Z)-19, 3H), 4.02 (s,
OCH3 of (E)-19 or (Z)-19, 3H), 5.05 (s, JPtH=36 Hz, CHPh of
(E)-19, 1H), 5.94 (s, JPtH=75 Hz, CHPh of (Z)-19, 1H). 31P{1H}
NMR (rt, CD2Cl2): δ -16.6 (s, JPtP=4581 Hz, (E)-19 or (Z)-19),
-17.6 (s, JPtP=4589 Hz, (E)-19 or (Z)-19).
[Pt(μ-Cl)(PMe2Ph){C(OiPr)dCHPh}]2 (20): 1H NMR (rt,
CD2Cl2): All peaks were broad and difficult to assign. 31P{1H}
NMR (rt, CD2Cl2): δ -15.9 (s, JPtP=4610 Hz, (E)-20 or (Z)-20),
-17.2 (s, JPtP=4596 Hz, (E)-20 or (Z)-20).
1
[Pt(μ-Cl)(PPh3){C(OEt)dCHPh}]2 (21): H NMR (rt, CD2-
Cl2): δ 3.86 (brm, OCH2 of (E)-21 or (Z)-21, 2H), 4.33 (brm,
OCH2 of (E)-21 or (Z)-21, 2H), 5.09 (brs, CHPh of (E)-21 or (Z)-
21, 1H), 5.40 (brs, CHPh of (E)-21 or (Z)-21, 1H). 31P{1H}
NMR (rt, CD2Cl2): δ 11.0 (s, JPtP=4885 Hz, (E)-21 or (Z)-21),
11.2 (s, JPtP=4870 Hz, (E)-21 or (Z)-21).
To the above solution of 18, PMe2Ph (0.014 mmol) was added
and NMR spectra were measured. 18 completely disappeared
and instead formation of a mixture of new (E)- and (Z)-alkenyl
complexes trans-[PtCl(PMe2Ph)2{C(OEt)dCHPh}] (23) was
observed in 56% and 29% yields (66:34), respectively. The
NMR sample tube was placed in an oil bath at 30 °C, and
NMR was periodically monitored to follow the E/Z isomeriza-
tion. After 75 h, yields of the (E)- and (Z)-alkenyl complexes
became 18% and 67% (21:79). (E)-23, 1H NMR (rt, CD2Cl2): δ
1.15 (t, JHH=7 Hz, OCH2CH3, 3H), 1.81 (vt, JPH=3 Hz, 195Pt
satellite peaks were not observed by overlapping, PCH3, 3H),
1.84 (vt, JPH=3 Hz, JPtH=32 Hz, PCH3, 3H), 4.10 (q, JHH
7 Hz, OCH2, 2H), 5.12 (s, JPtH =42 Hz, CHPh, 1H), 6.94 (t,
HH=7 Hz, p-Ph of dCHPh, 1H), 7.16 (t, JHH=8 Hz, m-Ph of
dCHPh, 2H), 7.36 (d, JHH=8 Hz, o-Ph of dCHPh, 2H), 7.46
=
J

5380 Organometallics, Vol. 28, No. 18, 2009
Tanaka et al.
(m, m- and p-Ph of PMe2Ph, 3H), 7.79 (m, o-Ph of PMe2Ph, 2H).
31P{1H} NMR (rt, CD2Cl2): δ -6.06 (s, JPtP=2802 Hz). (Z)-23,
1H NMR (rt, CD2Cl2): δ 1.14 (t, JHH=7 Hz, OCH2CH3, 3H),
114%/13) gas was detected by GC. Then, excess PMe2Ph
(0.0984 mmol) was added to the solution to give [Pt(PMe2-
Ph)3{C(OEt)dCHPh}]þ[Co(PMe2Ph)n(CO)m]- (29). The NMR
tube was placed in an oil bath at 30 °C, and the E/Z isomeriza-
tion was periodically monitored by NMR. (E)-28, 1H NMR (rt,
CD2Cl2): δ 1.39 (t, JHH=7 Hz, OCH2CH3, 3H), 3.84 (m, OCH2,
1H), 4.18 (m, OCH2, 1H), 5.04 (d, JPH = 4 Hz, CHPh, 1H).
31P{1H} NMR (rt, CD2Cl2): δ -7.48 (d, JPP=12 Hz, JPtP=2449
Hz), -11.76 (d, JPP=12 Hz, JPtP=3685 Hz). (Z)-28, 1H NMR
(rt, CD2Cl2): δ 1.31 (t, JHH=7 Hz, OCH2CH3, 3H), 3.67 (m,
1.64 (vt, JPH=4 Hz, JPtH=33 Hz, PCH3, 3H), 1.77 (vt, JPH
=
4 Hz, JPtH=32 Hz, PCH3, 3H), 3.68 (q, JHH=7 Hz, OCH2, 2H),
5.93 (s, JPtH =90 Hz, CHPh, 1H), 6.96 (t, JHH =7 Hz, p-Ph
of dCHPh, 1H), 7.11 (t, JHH=8 Hz, m-Ph of dCHPh, 2H), 7.38
(m, m- and p-Ph of PMe2Ph, 3H), 7.64 (m, o-Ph of PMe2Ph, 2H),
7.99 (d, JHH=8 Hz, o-Ph of dCHPh, 2H). 31P{1H} NMR (rt,
CD2Cl2): δ -7.45 (s, JPtP=2846 Hz).
Reactions of 19 and 20 with PMe2Ph were carried out
analogously to give trans-[PtCl(PMe2Ph)2{C(OMe)dCHPh}]
(24) and trans-[PtCl(PMe2Ph)2{C(OiPr)dCHPh}] (25), respec-
tively. (E)-24, 1H NMR (rt, CD2Cl2): δ 1.81 (br, PCH3, 6H), 3.74
(s, OCH3, 3H), 5.12 (s, JPtH=42 Hz, CHPh, 1H). 31P{1H} NMR
OCH2, 1H), 4.1 (m, OCH2, 1H), 5.74 (d, JPH =9 Hz, JPtH =
42 Hz, CHPh, 1H). 31P{1H} NMR (rt, CD2Cl2): δ -8.61 (d,
J
PP=12 Hz, JPtP =2409 Hz), -14.55 (d, JPP=12 Hz, JPtP =
3628 Hz). (E)-29, 1H NMR (rt, CD2Cl2): δ 4.48 (q, JHH=7 Hz,
OCH2, 2H), 5.3 (overlapped with solvent peak, JPtH=31 Hz,
1
(rt, CD2Cl2): δ -6.2 (s, JPtP=2783 Hz). (Z)-24, H NMR (rt,
CHPh, 1H). 31P{1H} NMR (rt, CD2Cl2): δ -8.75 (d, JPP
=
CD2Cl2): δ 1.64 (vt, JPH=4 Hz, JPtH=33 Hz, PCH3, 3H), 1.76
(vt, JPH=4 Hz, JPtH=30 Hz, PCH3, 3H), 3.45 (s, OCH3, 3H),
5.94 (s, JPtH=88 Hz, CHPh, 1H). 31P{1H} NMR (rt, CD2Cl2):
δ -7.1 (s, JPtP=2831 Hz). (E)-25, 1H NMR (rt, CD2Cl2): δ 1.070
(d, JHH =6 Hz, OCH(CH3)2, 6H), 1.83 (vt, JPH =4 Hz, 195Pt
satellite peaks were not observed by overlapping, PCH3, 3H),
22 Hz, JPtP=2597 Hz), -18.92 (t, JPP=22 Hz, JPtP=1813 Hz).
1
(Z)-29, H NMR (rt, CD2Cl2): δ 3.92 (q, JHH =7 Hz, OCH2,
2H), 6.55 (d, JPH=13 Hz, JPtH=64 Hz, CHPh, 1H). 31P{1H}
NMR (rt, CD2Cl2): δ -12.19 (d, JPP=24 Hz, JPtP=2691 Hz),
-19.92 (t, JPP=24 Hz, JPtP=1794 Hz).
Reaction of Aminocarbene Complexes (Ph3P)Cl(Me2NHC)-
Pt-M0L0n with Tertiary Phosphine Ligand. Reaction of (Ph3P)-
1.86 (vt, JPH=4 Hz, JPtH=34 Hz, PCH3, 3H), 4.97 (sep, JHH
=
6 Hz, OCH, 1H), 5.27 (s, JPtH =43 Hz, CHPh, 1H). 31P{1H}
NMR (rt, CD2Cl2): -5.03 (s, JPtP=2852 Hz). (Z)-25, 1H NMR
(rt, CD2Cl2): δ 1.074 (d, JHH=6 Hz, OCH(CH3)2, 6H), 1.63 (vt,
Cl(Me2NHC)Pt-Co(CO)4 (1) with PPh3. 1 C6H6 (97.6 mg,
3
0.122 mmol) and PPh3 (41.5 mg, 0.158 mmol) were dissolved in
acetone to give a yellow solution, which was stirred at room
temperature for 3 h to cause decoloration. The resultant solution
was concentrated, and excess benzene was added to precipitate the
product. After filtration, the precipitates were washed with ben-
zene and hexane and then dried under a vacuum to give a white
powder. Recrystallization from acetone/benzene gave trans-[PtCl-
(PPh3)2(CHNMe2)]þ[Co(CO)4]- C6H6 (30 C6H6) as pale yellow
JPH=4 Hz, JPtH=34 Hz, PCH3, 3H), 1.78 (vt, JPH=4 Hz, JPtH=
28 Hz, PCH3, 3H), 4.48 (sep, JHH=6 Hz, OCH, 1H), 6.04 (s,
J
J
PtH=90 Hz, CHPh, 1H). 31P{1H} NMR (rt, CD2Cl2): -7.68 (s,
PtP=2877 Hz).
Reactions of 21 with PPh3 was performed analogously to give
trans-[PtCl(PPh3)2{C(OEt)dCHPh}] (26). (E)-26, 1H NMR (rt,
3
3
CD2Cl2): δ 0.53 (t, JHH=7 Hz, OCH2CH3, 3H), 3.78 (q, JHH
=
needles. Yield: 64% (83.2 mg, 0.0784 mmol). Anal. Calcd
for C49H43ClCoNO4P2Pt: C, 55.45; H, 4.08; N, 1.32. Found: C,
55.25; H, 4.24; N, 1.34. Molar electric conductivity Λ (THF, rt):
7 Hz, OCH2, 2H), 5.06 (s, CHPh, 1H). 31P{1H} NMR (rt,
CD2Cl2): 20.8 (s, JPtP=3077 Hz). (Z)-26, 1H NMR (rt, CD2Cl2):
δ 0.80 (t, JHH =7 Hz, OCH2CH3, 3H), 2.50 (q, JHH =7 Hz,
OCH2, 2H), 4.94 (s, JPtH=84 Hz, CHPh, 1H). 31P{1H} NMR
(rt, CD2Cl2): 22.0 (s, JPtP=3170 Hz).
18 S cm2 mol-1
.
Reaction of (Ph3P)Cl(Me2NHC)Pt-Mn(CO)5 (2) with PPh3.
The acetone solution containing 2 (94.4 mg, 0.127 mmol) and
PPh3 (36.2 mg, 0.138 mmol) was stirred at 30 °C for 12 h. The
orange color of the solution turned yellow. Evaporation of
volatile matter gave a yellow solid, which was washed with
benzene and hexane. The solid was recrystallized from acetone/
Reaction of in Situ Prepared trans-[PtCl(PMe2Ph)2{C(NPh2)-
(CH2Ph)}]þCl- (22) with NEt3. cis-[PtCl2(PMe2Ph){C(NPh2)-
(CH2Ph)}] (5.7 mg, 0.0084 mmol) was dissolved in CD2Cl2, and
then 1,4-dioxane (0.012 mmol) was added as an internal stan-
dard. Then, PMe2Ph (0.0084 mmol) was added to the solution.
NMR analysis after 1 h revealed the formation of trans-[PtCl-
(PMe2Ph)2{C(NPh2)(CH2Ph)}]þCl- (22) (conv. 100%). 22: 1H
NMR (rt, CD2Cl2): δ 1.77 (vt, JPH=4 Hz, JPtH=31 Hz, PCH3,
benzene to give trans-[PtCl(PPh3)2(CHNMe2)]þ[Mn(CO)5]-
3
C6H6 (31 C6H6) as yellow microcrystals. Yield: 55% (76.1 mg,
0.0701 mmol). Anal. Calcd for C50H43ClMnNO5P2Pt: C, 55.33;
H, 3.99; N, 1.29. Found: C, 55.48; H, 4.00; N, 1.31.
3
3H), 1.81 (vt, JPH=4 Hz, JPtH=30 Hz, PCH3, 3H), 3.76 (s, JPtH=
31 Hz, CH2Ph, 2H). 31P{1H} NMR (rt, CD2Cl2): δ -9.3 (s,
Reaction of (Ph3P)Cl(Me2NHC)Pt-Co(CO)4 (1) with Ph2-
PC2H4PPh2 (dppe). 1 C6H6 (111.9 mg, 0.1401 mmol) and dppe
3
J
PtP=2530 Hz).
To the above solution of 22 was added NEt3 (0.0086 mmol),
(61.9 mg, 0.155 mmol) were dissolved in acetone and stirred at
room temperature for 1 h. The resultant solution was concen-
trated, and then excess benzene was added to precipitate the
product. Filtration gave a yellow solid, which was washed with
benzene and hexane and then dried under a vacuum to give a
pale yellow powder of [PtCl(dppe)(CHNMe2)]þ[Co(CO)4]-
(32). Yield: 79% (95.3 mg, 0.111 mmol).
and NMR spectra were measured. 22 completely disappeared
and instead formation of trans-[PtCl(PMe2Ph)2{(Z)-C(NPh2)d
CHPh}] ((Z)-27) was observed in 93% yield. The E/Z isomer-
ization was not detected at 30 °C for 21 h. (Z)-27: 1H NMR (rt,
CD2Cl2): δ 1.65 (vt, JPH=4 Hz, JPtH=28 Hz, PCH3, 3H), 1.71
(vt, JPH=4 Hz, 28 Hz, PCH3, 3H), 5.83 (s, JPtH=104 Hz, CHPh,
1H). 31P{1H} NMR (rt, CD2Cl2): δ -9.1 (s, JPtP=2907 Hz).
Reaction of in Situ Prepared (PhMe2P)(CO){μ-PhHCd-
(EtO)C}Pt-Co(CO)3 (13) with PMe2Ph. (PhMe2P)(CO){μ-
PhHCd(EtO)C}Pt-Co(CO)3 (13) was in situ prepared by the
reaction of (PhMe2P)Cl{(PhCH2)(EtO)C}Pt-Co(CO)4 (6) with
benzylamine. 6 (7.6 mg, 0.011 mmol) was dissolved in CD2Cl2.
Then dibenzyl in CD2Cl2 (0.0035 mmol) and CH4 (150 μL) were
added as internal standards. Then PhCH2NH2 (0.011 mmol)
was added to the solution to generate 13. After 3 h at 30 °C,
a mixture of (E)- and (Z)-13 was formed in 69 and 19%
(E/Z = 79:21) yields, respectively. Then 1 equiv of PMe2Ph
(0.011 mmol) was added to the solution. Formation of
cis-(PhMe2P)2{μ-PhHCd(EtO)C}Pt-Co(CO)3 (28) was con-
firmed by NMR, and an equimolar amount of CO (0.013 mmol,
Theoretical Calculations. DFT calculation of the model com-
plex trans-[PtCl(PH3)2{C(OMe)dCHPh}] was performed with
the Spartan06 program package (Wavefunction, Inc., Irvine,
CA) at the B3LYP level using the LACVP*. The optimized
structures represent the equilibrium geometries of the molecules
in the gas phase. The computed total energies of E and Z isomers
of trans-[PtCl(PH3)2{C(OMe)dCHPh}] were -4435310.41 and
-4435312.85 kJ/mol, respectively.
X-ray Structure Analysis. The crystallographic data were
measured on a Rigaku RASA-7R four-circle diffractometer
˚
using Mo KR (λ=0.71069 A) radiation with a graphite crystal
monochromator at -73 °C. A single crystal was selected by use
of a polarized microscope and mounted onto a capillary using
Paraton N oil. The unit cells were determined by the automatic
indexing of the 20 centered reflections. Intensity data were

Article
Organometallics, Vol. 28, No. 18, 2009 5381
collected using the ω-2θ technique to a maximum 2θ of 54.9°.
Intensities were corrected for Lorentz and polarization effects.
All calculations were performed using the CrystalStructure 3.824
crystallographic software package except for refinement, which
was performed using SHELXL-97.25 An absorption correction
was applied with the program PSI SCAN for 1, 2, and 6.
Structures were solved by the heavy-atom Patterson method26
for 1 and 2 and by direct methods (SIR92)27 for 6 and expanded
using Fourier techniques.28 All non-hydrogen atoms were re-
fined by full-matrix least-squares techniques with anisotropic
displacement parameters based on F2 with all reflections except
the incorporated solvent molecule in 2. All hydrogen atoms were
added geometrically and refined by using a riding model. For
complexes 1 and 2, intensity decay was observed in 3.39 and
21.21%, respectively, and the decay corrections were applied.
The C(15)-C(20) bond in 2 was restrained to be a six-membered
ring (AFIX 66 command). The crystallographic data and
selected bond distances and angles are summarized in Tables 3
and 4, respectively. For complex (E)-11, single crystals were
obtained from THF/hexane. However, sufficient diffraction
data could not be obtained, and only a brief structural feature
was discussed in the text. Two independent molecules of (E)-11
were found in the unit cell. The only Pt, Mo, and P atoms were
refined with anisotropic displacement parameters. The phenyl
and Cp rings in (E)-11 were restrained as rigid groups (AFIX 66
and AFIX 59, respectively). C(12) and C(38) atoms are located
and fixed at the positions of the difference Fourier peaks,
and their displacement parameters were not refined. Crystal
data for (E)-11: C26H27MoO4PPt, fw = 725.50, monoclinic,
˚
˚
˚
Cc (No. 9), a=33.381(17) A, b=9.06(3) A, c=18.360(18) A,
3
β=112.18(5)°, V=5144.1(181) A , Z=8, Dcalcd=1.873 g/cm3,
˚
μ(Mo Ka) = 59.891 cm-1, 2θmax = 55.0°, 5966 reflections
measured (5965 unique), R1 (wR2) =0.1283 (0.3691), GOF =
1.408.
(24) CrystalStructure 3.8, Crystal Structure Analysis Package,;
Rigaku and Rigaku/MMC: The Woodlands, TX 77381, 2000-2006.
(25) Sheldrick, G. M. SHELX-97, Programs for crystal structure
determination (SHELXS) and refinement (SHELXL); University of
€
€
Gottingen: Gottingen, Germany, 1997.
(26) PATTY: Beurskens, P. T.; Admiraal, G.; Beurskens, G.;
Bosman, W. P.; Garcia-Granda, S.; Gould, R. O.; Smits, J. M. M.;
Smykalla, C. The DIRDIF program system, Technical Report of the Crystal-
lography Laboratory; University of Nijmegen: The Netherlands, 1992.
(27) SIR92: Altomare, A.; Cascarano, G.; Giacovazzo, C.; Guagliardi,
A.; Burla, M.; Polidori, G.; Camalli, M. J. Appl. Crystallogr. 1994, 27, 435.
(28) DIRDIF99: Beurskens, P. T.; Admiraal, G.; Beurskens, G.;
Bosman, W. P.; de Gelder, R.; Israel, R.; Smits, J. M. M. The DIRDIF-
99 program system, Technical Report of the Crystallography Laboratory;
University of Nijmegen: The Netherlands, 1999.
Acknowledgment. This work was financially supported
by a grant-in-aid for Scientific Research from the
Ministry of Education, Culture, Sports, Science and
Technology of Japan.
Supporting Information Available: Crystallographic data are
given as CIF files for complexes 1, 2, 6, and (E)-11. This material
is available free of charge via the Internet at http://pubs.acs.org.