Characterization and phenylacetylene-assisted cyclometalation of an isolable hydrido-selenolato PtII complex having phosphite ligands, cis-[PtH(SeTrip){P(OPh)3}2]#

Article abstract of DOI:10.1246/bcsj.20130295

A hydridoselenolato Pt^II complex having P(OPh)₃ ligands, cis-[PtH(SeTrip){P(OPh)₃}₂] (Trip: 9-triptycyl), was synthesized by the reaction of TripSeH with [Pt{P(OPh)₃} ₂]. The structure was characterized by NMR spectroscopy and X-ray crystallography in comparison with the corresponding PPh₃ complex, cis-[PtH(SeTrip)(PPh₃)₂], indicating the stronger coordination of P(OPh)₃ to the Pt center than that of PPh ₃. On heating at 130 °C in xylene for 17 h, cis-[PtH(SeTrip)- {P(OPh)₃}₂] was converted to the corresponding 1,2-selenaplatinacycle (SP-42)-[Pt(kC¹,kSe⁹-TripSe(2-)) {P(OPh)₃}₂] through an intramolecular cyclization (cyclometalation). The reaction with dimethyl acetylenedicarboxylate (DMAD) gave a mixture of hydroselenation products (E)- and (Z)-(MeO₂C)CH= C(SeTrip)CO₂Me non-stereoselectively together with 1H-2-benzoselenin, dimethyl 7H-7,11b[1',2']-benzenoanthra[9,1-bc]selenin-2,3-dicarboxylate. In the reaction with phenylacetylene in toluene at 110 °C, phenylacetylene served as a hydrogen acceptor to form the 1,2-selenaplatinacycle and styrene. Based on the results of controlled experiments using cis-[PtD(SeTrip){P(OPh) ₃}₂] and phenylacetylene-d, the mechanism of the cyclometalation was proposed as the 1,2- (major) and 2,1- (minor) insertions of phenylacetylene into the Pt-H bond followed by cyclometalation between the Pt center and the triptycyl group. The reaction with phenylacetylene in the presence of excess P(OPh)₃ furnished a 1,2,3-oxaphosphaplatinacycle, (SP-4-2)-[Pt{kC,kP-(Z)-CH=C(Ph)-OP(OPh)₂}(SeTrip){P(OPh) ₃}], as a minor product, together with the 1,2-selenaplatinacycle in a decreased yield.

Full text of DOI:10.1246/bcsj.20130295

274
Bull. Chem. Soc. Jpn. Vol. 87, No. 2, 274-282 (2014)
© 2013 The Chemical Society of Japan
Selected Papers
Characterization and Phenylacetylene-Assisted Cyclometalation
of an Isolable Hydrido-Selenolato PtII Complex Having
Phosphite Ligands, cis-[PtH(SeTrip){P(OPh)3}2]#
Hitomi Kamon, Yutaro Aoki, Norio Nakata, and Akihiko Ishii*
Department of Chemistry, Graduate School of Science and Engineering, Saitama University,
255 Shimo-okubo, Sakura-ku, Saitama 338-8570
Received October 23, 2013; E-mail: ishiiaki@chem.saitama-u.ac.jp
A hydrido-selenolato PtII complex having P(OPh)3 ligands, cis-[PtH(SeTrip){P(OPh)3}2] (Trip: 9-triptycyl), was
synthesized by the reaction of TripSeH with [Pt{P(OPh)3}2]. The structure was characterized by NMR spectroscopy and X-
ray crystallography in comparison with the corresponding PPh3 complex, cis-[PtH(SeTrip)(PPh3)2], indicating the stronger
coordination of P(OPh)3 to the Pt center than that of PPh3. On heating at 130 °C in xylene for 17 h, cis-[PtH(SeTrip)-
{P(OPh)3}2] was converted to the corresponding 1,2-selenaplatinacycle (SP-4-2)-[Pt(κC1,κSe9-TripSe(2¹)){P(OPh)3}2]
through an intramolecular cyclization (cyclometalation). The reaction with dimethyl acetylenedicarboxylate (DMAD)
gave a mixture of hydroselenation products (E)- and (Z)-(MeO2C)CH=C(SeTrip)CO2Me non-stereoselectively together
with 1H-2-benzoselenin, dimethyl 7H-7,11b[1¤,2¤]-benzenoanthra[9,1-bc]selenin-2,3-dicarboxylate. In the reaction with
phenylacetylene in toluene at 110 °C, phenylacetylene served as a hydrogen acceptor to form the 1,2-selenaplatinacycle and
styrene. Based on the results of controlled experiments using cis-[PtD(SeTrip){P(OPh)3}2] and phenylacetylene-d, the
mechanism of the cyclometalation was proposed as the 1,2- (major) and 2,1- (minor) insertions of phenylacetylene into the
Pt-H bond followed by cyclometalation between the Pt center and the triptycyl group. The reaction with phenylacetylene
in the presence of excess P(OPh)3 furnished a 1,2,3-oxaphosphaplatinacycle, (SP-4-2)-[Pt{κC,κP-(Z)-CH=C(Ph)-
OP(OPh)2}(SeTrip){P(OPh)3}], as a minor product, together with the 1,2-selenaplatinacycle in a decreased yield.
In recent years, the transition-metal-mediated addition of
reaction of cis-[PtH(SeTrip)(PPh3)2] (1a) (Trip: 9-triptycyl)
with an electron-deficient, activated alkyne, dimethyl acetyl-
enedicarboxylate (DMAD) in benzene at 60 °C to produce (E)-
vinyl selenide 2 stereoselectively together with [Pt(dmad)-
(PPh3)2] (3) (Scheme 1), where we showed the necessity of the
initial dissociation of a PPh3 ligand to forward the reaction to
the next step.18
element-element and element-hydrogen bonds to alkynes has
been studied extensively.1-3 Hydroselenation of alkynes with
benzeneselenol (PhSeH) in the presence of [Pt(PPh3)4]4,5 as the
catalyst is one of such reactions to yield synthetically useful
vinyl selenides.6,7 In the stoichiometric reaction of PhSeH with
[Pt(PPh3)4] in benzene-d6 at room temperature, Ananikov and
Beletskaya observed the formation of a hydrido-selenolato PtII
complex, trans-[PtH(SePh)(PPh3)2], by NMR spectroscopy as
a minor product together with diselenolato complexes, cis- and
trans-[Pt(SePh)2(PPh3)2], as the major products; they proposed
the hydrido-selenolato PtII complex to be the key intermediate
in the hydroselenation.4,5
1a: R = Trip; L = PPh3
1b: R = Hhf; L = PPh3
L
L
SeR
H
1c: R = Trip; L2 = dppe
1d: R = Trip; L2 = dppf
1e: R = Dbb; L = PPh3
1f: R = tBu; L = PPh3
Pt
Since the first report by Ugo and co-workers on trans-
[PtH(SePh)(PPh3)2] in 1971,8,9 hydrido-selenolato PtII com-
plexes ([PtH(SeR)L2]) have been a rare class of compounds
probably due to their intrinsic instability. Thus, not only the
synthesis but also the reactivity of hydrido-selenolato PtII com-
plexes have not been explored sufficiently in comparison to
the sulfur congener, trans-[PtH(SAr)(PPh3)2].10-12 Recently,
we have succeeded in the isolation and characterization of a
series of cis-hydrido-selenolato PtII complexes having phos-
phine ligands, cis-[PtH(SeR)L2] 113-17 (L = phosphine ligands)
by taking advantage of sterically demanding substituents on the
selenium (Figure 1). We have also reported the stoichiometric
O
Trip
Hhf
Dbb
Figure 1. Isolable cis-hydrido-selenolato PtII complexes
having phosphine ligands, cis-[PtH(SeR)L2] 1 [dppe: 1,2-
bis(diphenylphosphino)ethane; dppf: 1,1¤-bis(diphenyl-
phosphino)ferrocene].
Published on the web December 5, 2013; doi:10.1246/bcsj.20130295

H. Kamon et al.
Bull. Chem. Soc. Jpn. Vol. 87, No. 2 (2014)
275
MeO2C
(DMAD)
CO2Me
(PhO)3P
Cl
Cl
NaBH4
EtOH
Ph3P
Ph3P
SeTrip
H
Pt
[Pt{P(OPh)3}2]
Pt
(PhO)3P
PhH, 60 °C
1a
SeTrip
(PhO)3P
TripSeH
Pt
H
SeTrip
THF/EtOH
rt, 2.5 h
(PhO)3P
H
[Pt(dmad)(PPh3)2]
3 (79%)
+
MeO2C
CO2Me
6 93%
Scheme 2. The synthesis of cis-[PtH(SeTrip){P(OPh)3}2]
(6) by the reaction of TripSeH with [Pt{P(OPh)3}2].
(E)-2 (24%)
Scheme 1. The stoichiometric reaction of cis-[PtH(SeTrip)-
(PPh3)2] (1a) with dimethyl acetylenedicarboxylate
(DMAD) to yield (E)-vinyl selenide 2 and [Pt(dmad)-
(PPh3)2] (3).
insertion reaction of Rh-H complexes reported by Ziólkowski
and co-workers.22 Here we report the synthesis and structure
characterization of cis-[PtH(SeTrip){P(OPh)3}2] (6) and the
reactions with DMAD and phenylacetylene.
Results and Discussion
Synthesis of cis-[PtH(SeTrip){P(OPh)3}2] (6). Hydrido-
PtII complex 6 was prepared by the reaction of 9-triptycene-
selenol (TripSeH) with [Pt{P(OPh)3}2], generated in situ
by reduction of [PtCl2{P(OPh)3}2]23 with sodium boro-
hydride in ethanol,24 in a high yield of 93% as yellow crystals
(Scheme 2). Hydrido PtII complexes with phosphite ligands are
fairly rare,25-28 and to our best knowledge, only trans-[PtHCl-
{P(OMe)3}2]25 and trans-[PtHCl{P(OPh)3}2]26 are known as
neutral hydrido complexes. Complex 6 is the first example of
the isolable hydrido-selenolato PtII complex bearing phosphite
ligands with cis-configuration.
Se
Se
Pt
PPh3
CO2Me
Ph3P
MeO2C
4
5
Figure 2. Five-membered 1,2-selenaplatinacycle 4 and 1H-
2-benzoselenin 5 derived from cis-[PtH(SeTrip)(PPh3)2]
(1a).
The structure of 6 was determined by NMR spectroscopic
1
An alternative characteristic reaction of hydrido-selenolato
PtII complexes 1a-1e is an intramolecular cyclization (cyclo-
metalation) under heating conditions to furnish the correspond-
ing 1,2-selenaplatinacycles.13-16 For example, five-membered
1,2-selenaplatinacycle 4 is formed from 1a. In addition, the
reaction of 4 with DMAD gives the carboselenation product,
1H-2-benzoselenin 5 (Figure 2).18,19
analyses and X-ray crystallography. In the H NMR spectrum,
the hydrido proton appeared at ¤ ¹5.23 as doublet of doublets
due to the two phosphorus atoms (2JP(trans)-H = 311, 2JP(cis)-H
=
6.4 Hz) accompanying the satellites due to the 195Pt isotope
(1JPt-H = 887 Hz). The proton is shifted downfield by 0.87
ppm in comparison with that of cis-[PtH(SeTrip)(PPh3)2] (1a)
(¤ ¹6.10) probably due to the weaker electron-donating ability
of P(OPh)3 than PPh3. The 31P{1H} NMR showed two doublets
(2JP-P = 34 Hz) at ¤ 104.2 and 125.8 with satellites by the
195Pt isotope (1JPt-P = 5184 and 3094 Hz, respectively). These
1JPt-P values are substantially larger than those for 1a [¤ 21.3
(1JPt-P = 3281 Hz) and 30.9 (1JPt-P = 2028 Hz)].13 The doublet
To gain further insight into the nature of hydrido-selenolato
PtII complexes, we have investigated the electronic and steric
effects of phosphorus ligands on the PtII center in the hydro-
selenation of alkynes and the cyclometalation. Triphenyl phos-
phite, P(OPh)3, is recognized as a weaker σ-donor, stronger π-
acceptor, and sterically less demanding phosphorus ligand than
triphenylphosphine.20 In the hydroselenation of alkynes utiliz-
ing Pt0 complexes, the oxidative addition step is the reaction of a
selenol with a Pt0 complex giving the hydrido-selenolato PtII
complex, and the reductive elimination corresponds to the final
step to produce vinyl selenide. In general, electron-accepting
ligands are less advantageous than electron-donating ones in the
oxidative addition of transition-metal complexes to an active
bond.21 In the reductive elimination stage, on the other hand, the
electronic effect is reverse, and the steric effect is substantially
important; sterically small ligands are less advantageous than
sterically demanding ligands.21 In these respects, it seems that
P(OPh)3 bears less effective factors than PPh3 in the both steps.
However, P(OPh)3 is expected to exert the electronic and steric
features in the insertion step of alkyne to the Pt-X (X = H or Se)
bond more advantageously than PPh3, as observed in the olefin
1
at ¤ 104.2 with the larger JPt-P value is assigned to the
phosphorus trans to the TripSe ligand and the other at ¤ 125.8
to that trans to the hydrido ligand. In the IR spectrum, the
absorption due to the Pt-H stretching vibration was observed
¹1
at 2086 cm [cf. 1a: ¯ = 2093 cm¹1].
~
The structure of 6 in the crystalline state was characterized
by X-ray crystallography (Figure 3). The Pt atom lies in a
distorted square-planar geometry; the sum of bond angles
around the Pt atom is 359.2°. The P(1)-Pt(1)-P(2) bond angle
is 103.08(4)°, and other angles around the Pt atom are less than
90°. The P-Pt-P angle is slightly wider than that of 100.87(4)°
in [PtH(SeTrip)(PPh3)2] (1a), suggesting the steric hindrance
among two P(OPh)3 and one TripSe ligands being comparable
to the corresponding steric hindrance among two PPh3 and one
TripSe in 1a. The Pt(1)-Se(1) bond length is comparable to that
of 1a [2.4272(5) ¡] and slightly shorter than or comparable to

276
Bull. Chem. Soc. Jpn. Vol. 87, No. 2 (2014)
Isolable Hydrido-Selenolato PtII Complex
(PhO)3P
(PhO)3P
Se
H
Pt
xylene
130 °C, 17 h
6
+
6
Se
7 : 6 = 3 : 7
(1H NMR)
Pt
P(OPh)3
(PhO)3P
7
Scheme 3. The thermal cyclometalation of 6 in xylene at
130 °C to give 1,2-selenaplatinacycle (7).
Figure 3. ORTEP drawing of cis-[PtH(SeTrip){P(OPh)3}2]
(6). Thermal ellipsoids are set at 50% probability. Hydro-
gen atoms except H(1) were omitted for clarity. Select-
ed bond lengths [¡] and bond angles [°]: Pt(1)-P(1)
2.2677(11), Pt(1)-P(2) 2.1859(12), Pt(1)-Se(1) 2.4314(5),
Pt(1)-H(1) 1.60(5), Se(1)-C(1) 1.974(4), P(1)-Pt(1)-P(2)
103.08(4), P(1)-Pt(1)-Se(1) 87.68(3), P(2)-Pt(1)-Se(1)
168.92(3), P(1)-Pt(1)-H(1) 173.4(19), P(2)-Pt(1)-H(1)
83.3(19), Se(1)-Pt(1)-H(1) 85.8(19).
(Se2naph)(PPh3)2].32 The shorter Pt-P bond lengths in 6 than
those in 1a indicate that the P(OPh)3 ligands coordinate to the
PtII center more strongly than the PPh3 ligands, which would be
explained in terms of the strong π-accepting nature of P(OPh)3
ligands.
Thermal Reaction of cis-[PtH(SeTrip){P(OPh)3}2] (6).
Heated in refluxing toluene for 17 h, 6 was recovered unreacted,
which is in stark contrast to the fact that 50% of (PPh3)2-
PtII complex 1a was converted to the corresponding 1,2-
selenaplatinacycle 4 on heating in refluxing toluene for 2 h. As
a result, higher temperatures were necessary for the cyclo-
metalation of 6: Heating at 130 °C in xylene for 17 h led to 30%
of conversion of 6 to the corresponding 1,2-selenaplatinacycle 7
(Scheme 3).
R'
R3P
R3P
SePh
SePh
R3P
R3P
Se
Se
Pt
Pt
[Pt(SePh)2(PR3)2]
[Pt(Se2naph)(PR3)2]
(R' = H)
In the 31P{1H} NMR of 7, two doublets appeared at ¤ = 96.7
and 116.9 (2JP-P = 45 Hz) accompanied by satellite signals due
to the 195Pt isotope (1JPt-P = 5056 and 2888 Hz, respectively).
[Pt(mt-Se2naph)(PR3)2]
(R' = tBu)
1
The doublet at ¤ = 96.7 having the larger JPt-P value (5056
Hz) is assigned to the phosphorus atom trans to the Se atom as
similarly as the case for 6.
PR3 = P(OPh)3 or PPh3
Figure 4. Diselenolato PPh3- and P(OPh)3-PtII complexes
reported by Woollins and co-workers.29
In the crystalline state, the Pt atom in 7 adopts a distorted
square-planar geometry, and the five-membered ring includ-
ing platinum and selenium atoms was slightly distorted
from planarity (Figure 5). As observed in the comparison
between P(OPh)3 complex 6 and PPh3 complex 1a, the Pt-Se
bond lengths of 1,2-selenaplatinalcycles 7 and 4 are similar
[2.4097(4) ¡ for 4], and the Pt-P bonds [2.2731(9) and
2.2175(9) ¡] in 7 are shorter than those in 4 [2.3318(10) and
2.2975(10) ¡]. The Pt(1)-P(1) bond was slightly longer than
the Pt(1)-P(2) bond, indicating that the carbon ligand has
larger trans influence than the selenium ligand does.
those of reported diselenolato-[P(OPh)3]2-PtII complexes; cis-
[Pt(SePh)2{P(OPh)3}2] [2.474(2)-2.481(2) ¡], [Pt(Se2naph)-
{P(OPh)3}2] [2.4600(7) and 2.4527(7) ¡], and [Pt(mt-Se2naph)-
{P(OPh)3}2] [2.4356(5) and 2.4256(5) ¡] (Figure 4).29 The
Pt(1)-P(1) bond [2.2677(11) ¡] is longer than the Pt(1)-P(2)
bond [2.1859(12) ¡], showing that the H ligand has larger trans
influence than that of the TripSe ligand. These Pt-P bond
lengths are comparable to those ranging from 2.224(4) to
2.290(2) ¡ observed in the above diselenolato-[P(OPh)3]2-PtII
complexes, and are shorter than those in (PPh3)2-PtII com-
plex 1a [2.3295(12) and 2.2474(12) ¡]. A similar tendency is
found between cis-[Pt(SePh)2{P(OPh)3}2] and cis-[Pt(SePh)2-
(PPh3)2]30,31 and between [Pt(Se2naph){P(OPh)3}2] and [Pt-
Reactions of cis-[PtH(SeTrip){P(OPh)3}2] (6) with
Alkynes.
The stoichiometric reaction of 6 with DMAD
was investigated first. Heating of 6 with DMAD in benzene
at 80 °C for 3 h gave a mixture of (E)- and (Z)-vinyl selenides
(E)-8 and (Z)-8, 1H-2-benzoselenin 5, and recovered 6 in the

H. Kamon et al.
Bull. Chem. Soc. Jpn. Vol. 87, No. 2 (2014)
277
Ph
6
7
+
PhCH=CH2
PhCH3
110 °C, 15 h
67%
Scheme 5. The stoichiometric reaction of cis-[PtH(SeTrip)-
{P(OPh)3}2] (6) with phenylacetylene in toluene at 110 °C
to give 1,2-selenaplatinacycle 7 and styrene.
SeTrip
(PhO)3P
(PhO)3P
Pt
+
Ph
PhCH3
D
110 °C, 15 h
6-d
Ph
+
H
D
Ph
D
H
Ph
D
H
H
+
7 +
H
H
Figure 5. ORTEP drawing of [Pt{κC1,κSe9-TripSe(2¹)}-
{P(OPh)3}2] (7). Thermal ellipsoids are set at 50%
probability. Hydrogen atoms were omitted for clarity.
Selected bond lengths [¡] and bond angles [°]: Pt(1)-P(1)
2.2731(9), Pt(1)-P(2) 2.2175(9), Pt(1)-Se(1) 2.4139(4),
Pt(1)-C(3) 2.087(3), Se(1)-C(1) 1.967(3), P(1)-Pt(1)-P(2)
94.02(3), P(1)-Pt(1)-Se(1) 89.03(2), P(2)-Pt(1)-Se(1)
167.75(3), P(1)-Pt(1)-C(3) 174.88(9), P(2)-Pt(1)-C(3)
91.04(9), Se(1)-Pt(1)-C(3) 85.85(9), Pt(1)-Se(1)-C(1)
97.37(10), Se(1)-C(1)-C(2) 110.0(2), C(1)-C(2)-C(3)
124.6(3), C(2)-C(3)-Pt(1) 117.9(2).
-d
cis- -d
trans- -d
9
:
0.5
:
0.5
(1H NMR)
Scheme 6. The stoichiometric reaction of 6-d with phenyl-
acetylene in toluene at 110 °C to give α-d-styrene and β-d-
styrene in the ratio of 9:1.
is in equilibrium with TripSeH and [Pt{P(OPh)3}2] at high
temperatures, and TripSeH during the equilibrium reacts with
DMAD to yield a mixture of (E)- and (Z)-8 and 5.18 However,
we cannot completely rule out the possibility that 8 and 5 are
formed by an identified pathway, because the formation ratio of
5 is lower than that in the controlled experiment.
Next, the reaction of 6 with phenylacetylene was examined.
While the reaction in refluxing benzene gave unidentifiable
materials with the recovery of 6, that performed at 110 °C
in toluene for 15 h produced 1,2-selenaplatinacycle 7 in 67%
yield (Scheme 5).33 Since cyclometalation of 6 to 7 does not
occur at 110 °C in toluene as mentioned above, phenylacety-
lene should play a crucial role for the cyclometalation. Indeed,
1H NMR analysis of the reaction mixture revealed the forma-
tion of styrene in an amount comparable to that of 7, suggesting
that the two hydrogen atoms in 6 were transferred to phenyl-
acetylene forming styrene.
To obtain insight into the mechanism of this unexpected
reaction, the following control experiments were carried out
employing deuterated 6 (6-d) and phenylacetylene-d. When
6-d was heated with phenylacetylene, the deuterium migrated
to the α-position of phenylacetylene mainly to yield α-d-
styrene (PhCD=CH2) together with β-d-styrene (cis- and trans-
PhCH=CHD) in the ratio of 9:1 (Scheme 6).34 This par-
tially regioselective formation of α-d-styrene clearly indicates
that styrene is not formed by addition of H2, eliminated from
6, to phenylacetylene, suggesting that an intermediate is
formed by the insertion of phenylacetylene to the Pt-H bond
where the 1,2-insertion leading to α-d-styrene is dominant.
On the other hand, heating of 6 with phenylacetylene-d fur-
nished PhCH=CHD as a 1:1 mixture of cis- and trans-isomers
(Scheme 7). It was separately verified that the isomerization
of trans-β-d-styrene to the cis-isomer occurred in the presence
6 or 7 in toluene at 110 °C.
SeTrip
H
DMAD
6
PhH
80 °C, 3 h
MeO2C
CO2Me
(E )- and (Z)-8
+
+
6
Se
MeO2C
CO2Me
5
(E )-8/(Z )-8/5/6 = 37/39/9/15 (judged by1H NMR)
Scheme 4. The stoichiometric reaction of cis-[PtH(SeTrip)-
{P(OPh)3}2] (6) with DMAD in benzene at 80 °C to yield
(E)-8, (Z)-8, and 5.
1
ratio of 37/39/9/15 on the basis the H NMR integral ratio
(Scheme 4). Previously we have observed a similar non-
stereoselective formation of vinyl selenides 8 together with 5
in the stoichiometric reaction of [PtH(SeTrip)(dppe)] [dppe:
1,2-bis(diphenylphosphino)ethane] with DMAD in refluxing
benzene. We have also verified that the reaction of TripSeH
with DMAD in benzene at 60 °C yielded a mixture of (E)-8,
(Z)-8, and 5 in the ratio of 16:18:18.18 Thus, it seems that 6

278
Bull. Chem. Soc. Jpn. Vol. 87, No. 2 (2014)
Isolable Hydrido-Selenolato PtII Complex
A plausible reaction pathway for the reaction of 6 with
phenylacetylene is depicted in Scheme 8: 1,2-Insertion of
phenylacetylene into the Pt-H bond of 6 occurs as the major
path, together with the 2,1-insetion as the minor one, to give
(E)-vinylplatinum intermediate 9 (only the major 1,2-insertion
is shown in Scheme 8). In this stage, the hydrido hydrogen
of 6 is transferred to the α-position of phenylacetylene. Then,
intramolecular cyclometalation occurs between the platinum
atom and the triptycyl group to yield styrene and 7, where the
hydrogen (H¤¤) on the triptycyl group migrates to the trans-β
position of the styrene. On this mechanism, trans-PhCH=CDH
should be formed stereoselectively in the control experiment
using phenylacetylene-d (Scheme 7). The non-stereoselective
formation of PhCH=CDH as the result is explained by the
ready cis-trans isomerization of PhCH=CDH in the presence
of platinum complexes 6 or 7 as mentioned above.
ism and modified Chalk-Harrod mechanism, respectively, in
hydrosilylation of alkynes with transition-metal catalysts.37
Ananikov and Beletskaya have described the insertion of
alkyne to the Pt-Se bond for their hydroselenation on the basis
of the formation of Markovnikov-type vinyl selenides.4,5 We
have also proposed the Pt-Se insertion mechanism in the
reaction shown in Scheme 1.18 The Pt-H insertion in Scheme 8
presents an alternative pathway in the reaction of alkynes with
PtII complexes. Incidentally, the reaction of hydrido-thiolato
PtII complex trans-[PtH(SC6H4-4-Cl)(PPh3)2], with phenyl-
acetylene in the presence of 4-ClC6H4SH has been reported to
furnish the Pt-H insertion product, cis-[Pt{(Z)-CH=CHPh}-
(SC6H4-4-Cl)(PPh3)2], under photoirradiation or in the presence
of AIBN.11 In the reaction, a pivotal role of thiyl radical
was proposed in the insertion with the anti-addition manner.
In addition, the insertion of 1-dodecyne to the Rh-H bond of
trans-[RhCl(H)(SPh)(PPh3)2] was observed to give the (E)-
vinylrhodium intermediate ([RhCl{(E)-CH=CH-n-C10H21}-
(SPh)(PPh3)n]).38 Reportedly, no solo reductive eliminations
of the vinylplatinum complex and the vinylrhodium complex to
yield vinyl sulfides occurred.11,38,39
In the stoichiometric hydroselenation of DMAD with cis-
[PtH(SeTrip)(PPh3)2] (1a), we have shown the necessity of the
initial dissociation of a PPh3 ligand from 1a to promote the
following reactions on the basis of the result that the addition
of excess PPh3 depressed the hydroselenation completely.18 To
ascertain whether this is true or not for the reaction of 6 with
phenylacetylene, a mixture of 6, phenylacetylene, and excess
P(OPh)3 was heated in toluene at 110 °C. As a result, the yield
of 1,2-selenaplatinacycle 7 was somewhat decreased from 67%
to 48%, and unexpectedly, complex 10 was isolated albeit in
a low yield of 16% (Scheme 9). The formation of 7 in a con-
siderable yield even in the presence of excess P(OPh)3, the
formation of 10 aside, suggests that hydrido-PtII complex 6
A similar alkyne-assisted cyclometalation, in which an
alkyne acts as a two-hydrogen acceptor, has been reported by
Chatani and co-workers in the synthesis of isoquinolones by the
reaction of N-2-pyridylmethyl aromatic amides with internal
alkynes in the presence of [Ni(cod)2]/PPh3.35 Templeton and
co-workers have also reported a related intramolecular cycliza-
tion of a three-coordinated PtII complex, generated via 2,1-
insertion of (triphenylsilyl)acetylene to the Pt-H bond of [Pt-
(Cl-nacnac)H(1-pentene)] [Cl-nacnac: bis(N-4-chlorophenyl)-
β-diiminato], to produce an alkene-coordinated Pt complex by
ortho-C-H activation.36
In the step of alkyne insertion into hydrido-selenolato PtII
complexes, there are two possible pathways, Pt-H insertion and
Pt-Se insertion, which correspond to Chalk-Harrod mechan-
+
6
Ph
D
PhCH3
110 °C, 15 h
Ph
H
D
Ph
D
Ph
P(OPh)3
SeTrip
(PhO)3P
PhO
7
+
+
:
Pt
O
H
H
H
+
6
7
48%
P
cis- -d
trans- -d
PhCH3
110 °C, 15 h
PhO
Ph
1
1
(1H NMR)
10 16%
Scheme 7. The stoichiometric reaction of 6 with phenyl-
acetylene-d in toluene at 110 °C to give cis- and trans-β-d-
styrenes.
Scheme 9. The stoichiometric reaction of 6 with phenyl-
acetylene in the presence of excess P(OPh)3 in toluene at
110 °C to give 7 and 1,2,3-oxaphosphaplatinacycle 10.
Se
Ph
H'
Se
Se
LnPt
LnPt
LnPt
H'
H"
H"
H
H
L = P(OPh)3
H'
H"
H
7 (n = 2)
Ph
6 (n = 2)
9
Ph
Scheme 8. A possible reaction pathway for the formation of selenaplatinacycle 7 and styrene in the reaction of cis-[PtH(SeTrip)-
{P(OPh)3}2] (6) with phenylacetylene.

H. Kamon et al.
Bull. Chem. Soc. Jpn. Vol. 87, No. 2 (2014)
279
6 coordinate to the PtII center more strongly than the PPh3
ligands in 1a, probably due to the stronger π-accepting ability
of P(OPh)3 ligands,20 leading to the dissociation of a P(OPh)3
ligand from 6 making the coordination-unsaturated state less
facile than that of a PPh3 ligand from 1a. This would result
in the non-stereoselective hydroselenation of DMAD with 6
unlike the case of the syn-selective hydroselenation of DMAD
with 1a. In addition, it is well known that P(OPh)3 is a weak
σ-donor,20 and consequently the platinum center in 6 would be
electron-deficient compared with the platinum center in 1a.
As our previous studies on the cyclometalation of the hydrido
PtII center to the triptycyl group in 1c15 or the dibenzobarrelenyl
group in 1e16 indicated that the dissociation of a phosphorus
ligand was not always important, the kinetics of the present
cyclometalation seems to be dependent on the electronic nature
of the Pt center. Thus, while we cannot deduce the mechanistic
aspect of the cyclometalation41 from the present results, the
result that 6 is less reactive than 1a to cyclometalation would
imply an important role of the nucleophilicity of the Pt cen-
ters rather than electrophilicity. On the other hand, the cyclo-
metalation of 6 was assisted by phenylacetylene to produce
selenaplatinacycle 7 together with styrene. A controlled experi-
ment evidenced that the hydrogen atom on the PtII center in 6
was transferred mainly to the α-position of phenylacetylene,
indicating that 1,2-insertion of phenylacetylene into the Pt-H
bond occurred there. The electron-deficient nature of the Pt
center in 6, in addition to the steric reason, would make the
hydroplatination of an alkyne favorable.22 Thus, we found that
the strongly coordinated P(OPh)3 ligands lead to a change of
the reaction pathway from the Pt-Se insertions for [PtH(SeR)-
(PPh3)2] to the Pt-H insertion for 6. We also reported the forma-
tion of PtII complex 10 in the thermal reaction of 6 and phenyl-
acetylene in the presence of excess P(OPh)3. 10 has a novel
five-membered 1,2,3-oxaphosphaplatinacycle ring system.
Figure 6. ORTEP drawing of (SP-4-2)-[Pt{κC,κP-(Z)-
CH=C(Ph)OP(OPh)2}(SeTrip){P(OPh)3}] (10). Thermal
ellipsoids are set at 50% probability, and hydrogen atoms
were omitted for clarity. One of two independent molecules
is shown and geometric parameters of the other molecule
are given in brackets: Selected bond lengths [¡] and bond
angles [°]: Pt(1)-P(1) 2.256(2) [2.253(2)], Pt(1)-P(2)
2.188(2) [2.189(2)], Pt(1)-Se(1) 2.4413(7) [2.4422(9)],
Pt(1)-C(40) 2.074(9) [2.057(7)], C(39)-C(40) 1.31(1)
[1.33(1)], P(2)-O(4) 1.600(6) [1.599(6)], P(1)-Pt(1)-P(2)
96.95(8) [97.66(8)], P(1)-Pt(1)-Se(1) 86.24(6) [85.17(6)],
P(2)-Pt(1)-Se(1) 171.92(6) [174.53(6)], P(1)-Pt(1)-C(40)
176.3(3) [177.1(2)], P(2)-Pt(1)-C(40) 79.6(3) [79.5(2)],
Se(1)-Pt(1)-C(40) 97.3(2) [97.7(2)], C(39)-C(40)-
Pt(1) 119.8(7) [120.6(6)], C(40)-C(39)-O(4) 118.7(8)
[118.6(7)], C(39)-O(4)-P(2) 113.7(5) [113.2(5)], O(4)-
P(2)-Pt(1) 108.0(2) [108.3(2)].
undergoes the attack of phenylacetylene at the four-coordinated
state and phenylacetylene inserts predominantly into the Pt-H
bond being sterically less hindered than the Pt-Se bond.
The formation of 10 formally requires the cleavage of a
strong Ph-O bond of P(OPh)3 in addition to the Pt-H bond with
formation of O-Cvinyl and Pt-Cvinyl bonds. Since we have not
determined the fate of the phenyl and the hydrogen, the for-
mation mechanism of 10 is not clear at present. Complex 10
has a novel ring system, five-membered 1,2,3-oxaphospha-
platinacycle.40 In the 1H NMR spectrum of 10, the vinyl proton
resonated at ¤ = 5.49-5.51 as a doublet of doublets by two 31P
Experimental
General Procedure. Melting points were determined on
1
a Melt-Temp capillary tube apparatus and are uncorrected. H,
13C, and 31P NMR spectra were recorded on Bruker AVANCE-
300 (300 MHz for 1H), AVANCE-400 (400, 101, and 162 MHz,
respectively), and AVANCE-500 (500, 126, and 202 MHz,
respectively) spectrometers at room temperature, unless other-
wise noted. IR spectra were recorded with a Perkin-Elmer
System 2000 FTIR spectrometer. Elemental Analyses were
performed at Comprehensive Analysis Center for Science,
Saitama University. Solvents were dried by standard methods
and freshly distilled prior to use. Anhydrous diethyl ether and
THF were purchased from Kanto Chemical Co., Inc. and used
without further purification. Column chromatography was
performed with silica gel (70-230 mesh) and eluent is shown
in parentheses. TripSeH was prepared according to a reported
procedure.42 Styrene-trans-β-d was prepared as a mixture with
styrene-α-d (the ratio of trans-β-d/α-d 84:16) by reduction of
phenylacetylene with DIBAH in the presence of [NiCl2(PPh3)2]
followed by quenching with D2O.43
2
nuclei (2JP(trans)-H = 6.5, JP(cis)-H = 4 Hz) accompanying satel-
lite signals due to the 195Pt isotope. In the 31P{1H} NMR, two
doublets were observed at ¤ = 113.0 (2JP-P = 33, 1JPt-P = 4606
1
Hz) and 116.7 (2JP-P = 33, JPt-P = 3393 Hz). The structure of
10 was finally identified by X-ray crystallography as depicted
in Figure 6. The Pt atom adopts a distorted planar geometry
and the five-membered ring involving Pt, P, and O atoms is
almost planar.
Conclusion
We have succeeded in the synthesis of an isolable hydrido-
selenolato PtII complex cis-[PtH(SeTrip){P(OPh)3}2] (6) that
has two P(OPh)3 ligands with cis-configuration and in the full
characterization of the structure in comparison with the PPh3
analogue cis-[PtH(SeTrip)(PPh3)2] (1a). The P(OPh)3 ligands in
Synthesis of cis-[PtH(SeTrip){P(OPh)3}2] (6). [PtCl2{P-
(OPh)3}2] was prepared by a reported procedure:26 A solution
of K2[PtCl4] (1.414 g, 3.41 mmol) and P(OPh)3 (1.8 mL, 6.85
mmol) in H2O (30 mL) and CH2Cl2 (30 mL) was stirred at room

280
Bull. Chem. Soc. Jpn. Vol. 87, No. 2 (2014)
Isolable Hydrido-Selenolato PtII Complex
temperature for 4 days to give [PtCl2{P(OPh)3}2] (2.25 g, 74%)
as a white powder: 31P{1H} NMR ¤ = 60.2 (1JPt-P = 5696 Hz).
To a mixture of [PtCl2{P(OPh)3}2] (227.2 mg, 0.256 mol) and
NaBH4 (44.0 mg, 1.165 mmol) was added ethanol (4 mL), and
the mixture was stirred at room temperature for 10 min.24 To the
solution of [Pt{P(OPh)3}2] was added a solution of TripSeH
(77.8 mg, 0.233 mmol) in THF (3 mL), and the reaction mixture
was stirred at room temperature for 2.5 h. After removal of
the solvent under reduced pressure, to the residue was added
dichloromethane (ca. 5 mL) and the solution was filtered
through a pad of Celiteμ. After removal of the solvent of
the filtrate under reduced pressure, the residue was purified
by column chromatography (hexane/CH2Cl2 = 1/1) to give
cis-[PtH(SeTrip){P(OPh)3}2] (6) (251.8 mg, 93%): Pale yellow
crystals, mp 184-186 °C decomp. 1H NMR (500 MHz, CDCl3):
¤ ¹5.23 (dd, 2JP(trans)-H = 311, 2JP(cis)-H = 6.4, 1JPt-H = 887
Hz, 1H), 5.24 (s, 1H), 6.61 [br s, 3H; Trip; at 328 K: ¤ = 6.64
(br t, J = 7 Hz)], 6.72 (d, J = 6.5 Hz, 6H; o-H of P(OPh)3),
6.84 (t, J = 7.3 Hz, 3H; p-H of P(OPh3)), 6.99-7.07 (m, 9H; 3H
for p-H of P(OPh)3 and 6H of Trip), 7.19-7.24 (m, 6H), 7.36
(t, J = 7.0 Hz, 6H; m-H of P(OPh)3), 7.45 (d, J = 7.5 Hz, 6H;
o-H of P(OPh)3), 7.73 (br s, 3H; Trip; at 328 K: ¤ = 7.73 (d,
J = 7.5 Hz)); 13C{1H} NMR (101 MHz, CDCl3): ¤ 54.6 (CH),
column chromatography (hexane/CH2Cl2 = 1/1) to give 1,2-
selenaplatinacycle 7 (19.5 mg, 67%): Pale yellow crystals,
mp 193-194 °C decomp. H NMR (400 MHz, CDCl3): ¤ 5.23
1
(s, 1H), 6.60 (dt, J = 7.5, 2.5 Hz, 1H), 6.88-6.94 (m, 20H),
7.12 (t, J = 7 Hz, 3H), 7.20-7.28 (m, 14H), 7.77-7.83 (m, 3H);
13C{1H} NMR (101 MHz, CDCl3): ¤ 55.7 (CH), 64.6 (C),
119.2 (CH; CH of Trip), 120.8 [CH; o-CH of P(OPh)3], 120.9
[CH; o-CH of P(OPh)3], 122.1 (CH; 2CH of Trip), 124.2 (CH;
2CH of Trip), 124.5 (CH; 2CH of Trip), 124.6 (CH; 2CH of
Trip), 124.7 [CH; 2(p-CH) of P(OPh)3], 129.4 [CH; m-CH of
P(OPh)3], 129.6 [CH; m-CH of P(OPh)3], 137.6 (dd, JP-C = 12,
6.7 Hz, CH; CH of Trip), 144.0 (d, JP-C = 5 Hz, C; C of Trip),
145.9 (C; 2C of Trip), 146.6 (d, JP-C = 126 Hz, C; C of Trip),
149.3 (C; 2C of Trip), 150.6 [d, JP-C = 7 Hz, C; ipso-C of
P(OPh)3], 151.2 [d, JP-C = 7 Hz, C; ipso-C of P(OPh)3], 165.6
(d, JP-C = 5 Hz, C; C of trip) (one of CH carbons of Trip,
which correlates to the proton observed at ¤ 6.60 (dt), was not
assigned due to overlapping with signals appearing between
¤ 124.2 to 124.7); 31P{1H} NMR (202 MHz, CDCl3): ¤ 96.7
(d, 2JP-P = 45, 1JPt-P = 5056 Hz), 116.9 (d, 2JP-P = 45, 1JPt-P
=
2888 Hz). Anal. Calcd for C56H42O6P2PtSe: C, 58.64; H,
3.69%. Found: C, 58.41; H, 3.65%.
Detection of Styrene:
6 (27.7 mg, 0.0241 mmol) and
3
58.1 (dd, JP-C = 15, 6 Hz, C), 120.9 [d, J = 4 Hz, CH; o-CH
phenylacetylene (4.0 ¯L, 3.7 mg, 0.036 mmol) were placed in
a valved NMR tube, and the NMR tube was connected to a
vacuum line. The NMR tube was cooled with liquid nitrogen
and evacuated, and into it was condensed ca. 0.5 mL of toluene-
d8. The valve of the NMR tube was closed and the tube was
disconnected from the vacuum line and warmed naturally. The
NMR tube was heated by being immersed in an oil bath at
110 °C for 6 h. The 1H NMR spectrum (300 MHz) displayed the
signals of styrene at ¤ 5.08 (dd, J = 11, 0.9 Hz) for the trans-
β-proton, at ¤ 5.60 (dd, J = 18, 0.9 Hz) for the cis-β-proton,
and at ¤ 6.56 (dd, J = 18, 11 Hz) for the α-proton together
with signals for 1,2-selenaplatinacycle 7 and unreacted 6. The
integral ratio of 7/styrene/6 was 34/39/27.
of P(OPh)3], 121.2 [d, J = 6 Hz, CH; o-CH of P(OPh)3], 122.0
(CH; Trip), 123.8 (CH; Trip), 124.1 (CH; Trip), 124.8 [CH;
p-CH of P(OPh)3], 125.0 [CH; p-CH of P(OPh)3], 126.9 (br s,
CH; Trip), 129.3 [CH; m-CH of P(OPh)3], 129.7 [CH; m-CH of
P(OPh)3], 146.0 (br s, C; Trip), 148.5 (C; Trip), 150.4 [d, J =
7 Hz, C; ipso-C of P(OPh)3], 151.2 [d, J = 5 Hz, C; ipso-C
of P(OPh)3]; 31P{1H} NMR (202 MHz, CDCl3): ¤ 104.2 (d,
1
2JP-P = 34, 1JPt-P = 5184 Hz), 125.8 (d, 2JP-P = 34, JPt-P
=
¹1
~
3094 Hz); IR (KBr): ¯ 2086 cm (Pt-H). Anal. Calcd for
C56H44O6P2PtSe: C, 58.54; H, 3.86%. Found: C, 58.08; H,
3.89%.
Thermal Reaction of cis-[PtH(SeTrip){P(OPh)3}2] (6). A
solution of 6 (13.6 mg, 0.011 mmol) in xylene (2 mL) was
heated at 130 °C for 17 h. The solvent was removed under
reduced pressure to give a mixture of (SP-4-2)-[Pt{κC1,κSe9-
TripSe(2¹)}{P(OPh)3}2] (7) and 6 in the ratio of 3:7 on the
Thermal Reaction of cis-[PtD(SeTrip){P(OPh)3}2] (6-d) in
the Presence of Phenylacetylene. Synthesis of [PtD(SeTrip)-
{P(OPh)3}2] (6-d): D2O (0.4 mL) was added to a solution of
6 (70 mg, 0.061 mmol) in toluene (2 mL) under argon atmos-
phere, and the mixture was heated under reflux for 1.5 h.
Removal of the solvent in vacuo left [PtD(SeTrip){P(OPh)3}2]
1
basis of the integral ratio in the H NMR spectrum.
Reaction of cis-[PtH(SeTrip){P(OPh)3}2] (6) with DMAD.
A solution of DMAD in benzene (0.8 M, 0.32 mL, 0.261 mmol)
was added to a solution of 6 (99.1 mg, 0.0863 mmol) in
benzene (4 mL) at room temperature under argon atmosphere.
The mixture was heated at 80 °C for 3 h. The solvent was
removed under reduced pressure to give a mixture of 6 (14.9
mg, 15%), (E)-87 (15.3 mg, 37%), (Z)-87 (15.9 mg, 39%), and
1H-2-benzoselenin 57 (3.7 mg, 9%). The yields of 6, (E)-8,
(Z)-8, and 5 were calculated on the basis of the integral ratio in
1
(6-d). The H NMR spectrum showed the complete disappear-
ance of the Pt-H signal. 6-d: 31P{1H} NMR (162 MHz, CDCl3):
2
1
2
¤ 103.6 (d, JP-P = 34, JPt-P = 5184 Hz), 124.6 (td, JD-P
=
2
1
78, JP-P = 36, JPt-P = 3094 Hz).
Thermal Reaction of cis-[PtD(SeTrip){P(OPh)3}2] (6-d)
with Phenylacetylene: 6-d (13.9 mg, 0.0121 mmol) and
phenylacetylene (2.0 ¯L, 1.9 mg, 0.0182 mmol) were placed in
a valved NMR tube, and the NMR tube was connected to a
vacuum line. The NMR tube was cooled with liquid nitrogen
and evacuated, and into it was condensed ca. 0.5 mL of toluene-
d8. The valve of the NMR tube was closed and the tube was
disconnected from the vacuum line and warmed naturally. The
NMR tube was heated by being immersed in an oil bath at
1
the H NMR spectrum of the reaction mixture.
Thermal Reaction of cis-[PtH(SeTrip){P(OPh)3}2] (6) in
the Presence of Phenylacetylene. Isolation of (SP-4-2)-
[Pt{κC1,κSe9-TripSe(2¹)}{P(OPh)3}2] (7):
A solution of
phenylacetylene in toluene (0.9 M, 0.04 mL, 0.038 mmol) was
added to a solution of 6 (29.0 mg, 0.025 mmol) in toluene
(2 mL) at room temperature under argon atmosphere. The mix-
ture was heated at 110 °C for 15 h, and then the solvent was
removed under reduced pressure. The residue was purified by
1
110 °C for 15 h. The H NMR spectrum (300 MHz) displayed
signals of α-d-styrene (PhCD=CH2), cis- and trans-β-d-
styrenes (PhCH=CDH) and styrene (PhCH=CH2) at ¤ 5.07
(d, J = 11 Hz, trans-β-H of cis-PhCH=CDH), 5.08 (dd, J =

H. Kamon et al.
Bull. Chem. Soc. Jpn. Vol. 87, No. 2 (2014)
281
11, 1 Hz, trans-β-H of PhCH=CH2), 5.08 (pseudo q, JD-H
=
=
decomp. 1H NMR (500 MHz, CDCl3): ¤ 5.38 (s, 1H), 5.50 (dd,
J = 6.5, 4 Hz, JPt-H = 33 Hz, 1H), 6.24 (d, J = 7.8 Hz, 2H),
2
J
H-H = 1.4 Hz, trans-β-H of PhCD=CH2), 5.57 (dt, JD-H
2.6 Hz, JH-H = 1.0 Hz, trans-β-H of PhCD=CH2), 5.58 (d,
J = 18 Hz, cis-β-H of trans-PhCH=CDH), 5.59 (dd, J = 18,
1 Hz, cis-β-H of PhCH=CH2), 6.53-6.61 (m, α-Hs of cis- and
trans-PhCH=CDH and PhCH=CH2) together with 1,2-selena-
platinacycle 7, recovered 6-d and a small amount of 6. The
ratio of PhCD=CH2/cis-PhCH=CDH/trans-PhCH=CDH/
PhCH=CH2 was 63/3.5/3.5/30.
6.75 (dt, J = 7.5, 0.8 Hz, 3H), 6.84 (t, J = 7.8 Hz, 2H), 6.88 (dt,
J = 7, 1 Hz, 3H), 6.94 (t, J = 7.5 Hz, 1H), 7.13 (t J = 7 Hz,
3H), 7.16 (d, J = 8.5 Hz, 4H), 7.21-7.26 (m, 8H), 7.29-7.33
(m, 13H), 7.75 (d, J = 7.5 Hz, 3H); 13C{H} NMR (101 MHz,
3
CDCl3): ¤ 54.6 (CH), 54.9 (dd, JP-C = 12, 4 Hz, C), 120.4 (d,
J = 6 Hz, CH), 121.4 (d, J = 6 Hz, CH), 122.0 (CH), 122.8 (dd,
2JP-C = 153, 8 Hz, CH), 124.0 (CH), 124.6 (CH), 124.8 (CH),
125.1 (CH), 125.2 (CH), 126.9 (CH), 126.9 (CH), 127.7 (CH),
129.6 (CH), 129.7 (CH), 145.1 (C), 147.9 (C), 150.8 (d, J =
7 Hz, C), 151.0 (d, J = 7 Hz, C), 153.9 (d, J = 6 Hz, C), 154.2
Thermal Reaction of cis-[PtH(SeTrip){P(OPh)3}2] (6)
with Phenylacetylene-d.
Phenylacetylene-d:
Phenyl-
acetylene (1.0 mL, 9.11 mmol) in ether (10 mL) was treated
with BuLi (1.59 M, 6.9 mL, 10.9 mmol) at 0 °C. After stirring
for 1 h at 0 °C, D2O (4 mL) was added. The mixture was
extracted with ether, and the extract was dried over anhydrous
sodium sulfate and evaporated to dryness to give phenyl-
acetylene-d (0.82 g, 87%, 97%-D).
(d, J = 6 Hz, C); 31P{1H} NMR (202 MHz, CDCl3): ¤ 113.0 (d,
1
2JP-P = 33, 1JPt-P = 4606 Hz), 116.7 (d, 2JP-P = 33, JPt-P
=
3393 Hz). Anal. Calcd for C58H44O6P2PtSe: C, 59.39; H,
3.78%. Found: C, 59.86; H, 3.92%.
X-ray Crystallographic Analyses of 6, 7, and 10. Pale-
yellow single crystals of 6, 7, and 10 were grown by slow
evaporation of their saturated toluene solutions at ¹18 °C.
The intensity data were collected at 103 K on a Bruker AXS
SMART diffractometer employing graphite-monochromated
Mo Kα radiation (- = 0.71073 ¡). The structures were solved
by direct methods and refined by full-matrix least-squares
procedures on F2 for all reflections (SHELX-97).44 Hydrogen
atoms except the PtH hydrogen of 6 were located by assuming
ideal geometry and were included in the structure calculations
without further refinement of the parameters. Crystallographic
data have been deposited with Cambridge Crystallographic
Data Centre: Deposition number CCDC-965691, -965692, and
-965693 for compounds 6, 7, and 10, respectively. Copies of
the data can be obtained free of charge via http://www.ccdc.
cam.ac.uk/conts/retrieving.html (or from the Cambridge Crys-
tallographic Data Centre, 12, Union Road, Cambridge, CB2
1EZ, U.K.; Fax: +44 1223 336033; e-mail: deposit@ccdc.cam.
ac.uk).
Thermal Reaction of 6 with Phenylacetylene-d: Complex
6 (14.3 mg, 0.0124 mmol) and phenylacetylene-d (2.0 ¯L, 1.9
mg, 0.018 mmol) were placed in a valved NMR tube, and the
NMR tube was connected to a vacuum line. The NMR tube
was cooled with liquid nitrogen and evacuated, and into it
was condensed ca. 0.5 mL of toluene-d8. The valve of the NMR
tube was closed and the tube was disconnected from the
vacuum line and warmed naturally. The NMR tube was heated
by being immersed in an oil bath at 110 °C for 15 h. The
1H NMR spectrum (300 MHz) displayed signals at ¤ 5.07
(d, J = 11 Hz, trans-β-H of cis-PhCH=CDH), 5.08 (dd, J =
11, 1 Hz, trans-β-H of PhCH=CH2), 5.58 (d, J = 18 Hz, cis-β-
H of trans-PhCH=CDH), 5.59 (dd, J = 18, 1 Hz, cis-β-H
of PhCH=CH2), and 6.53-6.59 (m, α-Hs of cis- and trans-
PhCH=CDH and PhCH=CH2) together with 1,2-selenaplati-
nacycle 7 and unreacted 6. The ratio of cis-PhCH=CDH/trans-
PhCH=CDH/PhCH=CH2 was 45.7/45.7/8.6.
Thermal Isomerization of trans-β-d-Styrene in the Pres-
ence of 6 or 7. A toluene-d8 (0.5 mL) solution of trans-
PhCH=CDH (the ratio of trans-PhCH=CDH/PhCD=CH2 =
84:16) (5 ¯L, 0.043 mmol) and 6 (24.8 mg, 0.0216 mmol) in
an NMR tube under argon atmosphere was heated at 110 °C for
6 h. The ratio of cis-PhCH=CDH/trans-PhCH=CDH deter-
mined by 1H NMR spectroscopy was 0.9:1.0. In a similar
manner, a toluene-d8 solution (0.5 mL) of trans-PhCH=CDH
(4 ¯L, 0.0345 mmol) and 7 (19.1 mg, 0.0167 mmol) was
heated at 110 °C for 6 h. The ratio of cis-PhCH=CDH and
Crystal Data for 6: C56H44O6P2PtSe, MW: 1148.90, tri-
ꢀ
clinic, space group P1, Z = 2, a = 13.0955(6), b = 13.7065(6),
c = 15.4994(8) ¡, ¡ = 97.141(1), ¢ = 103.705(1), £ =
¹3
116.683(1)°,
V = 2328.14(19) ¡3,
Dcalcd = 1.639 g cm ,
R1 [I > 2σ(I)] = 0.0350, wR2 (all data) = 0.0878 for 8643
reflections, 599 parameters, GOF = 1.019.
Crystal Data for 7:
triclinic, space group P1, Z = 2, a = 11.7925(12), b =
12.9308(13), c = 17.7593(17) ¡, ¡ = 95.307(2), ¢ =
C56H42O6P2PtSe, MW: 1146.89,
ꢀ
1
trans-PhCH=CDH determined by H NMR spectroscopy was
104.917(2), £ = 116.598(2)°, V = 2271.2(4) ¡3, Dcalcd
=
0.8:1.0.
1.677 g cm¹3, R1 [I > 2σ(I)] = 0.0282, wR2 (all data) = 0.0716
for 8398 reflections, 595 parameters, GOF = 0.950.
Reaction of cis-[PtH(SeTrip){P(OPh)3}2] (6) with Phenyl-
acetylene in the Presence of P(OPh)3.
A solution of
Crystal Data for 10:
C58H44O6P2PtSe, MW: 1172.92,
phenylacetylene in toluene (0.9 M, 0.04 mL, 0.038 mmol) was
added to a mixture of 6 (29.0 mg, 0.025 mmol) and P(OPh)3
(10 ¯L, 0.038 mmol) in toluene (2 mL) at room temperature
under argon atmosphere. The mixture was heated at 110 °C for
15 h, and then the solvent was removed under reduced pressure.
The residue was subjected to column chromatography (hexane/
CH2Cl2 = 1/1) to give 1,2,3-oxaphosphaplatinacycle 10 (4.6
mg, 16%) and 1,2-selenaplatinacycle 7 (14.0 mg, 48%) in this
order.
orthorhombic, space group Pca21, Z = 8, a = 17.2952(7), b =
16.7925(7), c = 33.0774(13) ¡, V = 9606.7(7) ¡3, Dcalcd
=
1.622 g cm¹3, R1 [I > 2σ(I)] = 0.0503, wR2 (all data) = 0.0690
for 21275 reflections, 1225 parameters, and 1 restraint, GOF =
1.021.
This work was supported by a Grant-in-Aid for Science
Research (C) (No. 21550035) and a Grant-in-Aid for Scientific
Research on Priority Areas (Nos. 19027014 and 20036013,
Synergy of Elements) from the Ministry of Education, Culture,
Sports, Science and Technology, Japan.
(SP-4-2)-[Pt{κC,κP-(Z)-CH=C(Ph)OP(OPh)2}(SeTrip)-
{P(OPh)3}] (10):
Yellow white crystals, mp 205-206 °C

282
Bull. Chem. Soc. Jpn. Vol. 87, No. 2 (2014)
Isolable Hydrido-Selenolato PtII Complex
J. Chem. Soc., Dalton Trans. 1997, 1831.
References
23 S. J. Sabounchei, A. Naghipour, Molecules 2001, 6, 777.
24 N. Nakata, S. Fukazawa, A. Ishii, Organometallics 2009,
28, 534.
#
Dedicated to Professor Renji Okazaki on the occasion of
his 77th birthday.
25 W. R. Meyer, L. M. Venanzi, Angew. Chem., Int. Ed. Engl.
1984, 23, 529.
1
2
I. Beletskaya, C. Moberg, Chem. Rev. 1999, 99, 3435.
F. Alonso, I. P. Beletskaya, M. Yus, Chem. Rev. 2004, 104,
26 H. Itaya, K. Nakajima, Jpn. Tokkyo Koho JP 1968-30031;
H. Itaya, K. Nakajima, Chem. Abstr. 1976, 84, 16722.
27 A. Crispini, K. N. Harrison, A. G. Orpen, P. G. Pringle,
J. R. Wheatcroft, J. Chem. Soc., Dalton Trans. 1996, 1069.
28 M. Green, D. M. Grove, J. L. Spencer, F. G. A. Stone,
J. Chem. Soc., Dalton Trans. 1977, 2228.
3079.
3
Hydrofunctionalization in Topics in Organometallic Chem-
istry, ed. by V. P. Ananikov, M. Tanaka, 2013, Vol. 43. doi:10.
1007/978-3-642-33735-2.
4
V. P. Ananikov, D. A. Malyshev, I. P. Beletskaya, G. G.
Aleksandrov, I. L. Eremenko, J. Organomet. Chem. 2003, 679,
29 A. L. Fuller, F. R. Knight, A. M. Z. Slawin, J. D. Woollins,
Eur. J. Inorg. Chem. 2010, 4034.
162.
5
V. P. Ananikov, M. A. Kabeshov, I. P. Beletskaya, G. G.
30 V. P. Ananikov, I. P. Beletskaya, G. G. Aleksandrov, I. L.
Eremenko, Organometallics 2003, 22, 1414.
Aleksandrov, I. L. Eremenko, J. Organomet. Chem. 2003, 687,
451.
31 M. S. Hannu, R. Oilunkaniemi, R. S. Laitinen, M. Ahlgén,
Inorg. Chem. Commun. 2000, 3, 397.
6
G. Mugesh, W.-W. du Mont, H. Sies, Chem. Rev. 2001,
101, 2125.
32 S. M. Aucott, H. L. Milton, S. D. Robertson, A. M. Z.
Slawin, G. D. Walker, J. D. Woollins, Chem.®Eur. J. 2004, 10,
1666.
7
C. W. Nogueira, G. Zeni, J. B. T. Rocha, Chem. Rev. 2004,
104, 6255.
8
R. Ugo, G. La Monica, S. Cenini, A. Segre, F. Conti,
33 1,2-Selenaplatinacycle 7 was also formed in the reaction of
6 with 1-hexyne in toluene at 110 °C.
J. Chem. Soc. A 1971, 522.
9
A. E. Keskinen, C. V. Senoff, J. Organomet. Chem. 1972,
34 In the reaction of 6-d and styrene, undeuterated styrene was
formed (30%) together with the deuterated styrenes (70%). This
would be due to a fast D-H exchange of 6-d by residual H2O under
the reaction conditions.
35 H. Shiota, Y. Ano, Y. Aihara, Y. Fukumoto, N. Chatani,
J. Am. Chem. Soc. 2011, 133, 14952.
36 N. M. West, P. S. White, J. L. Templeton, Organometallics
2008, 27, 5252.
37 S. Sakaki, N. Mizoe, M. Sugimoto, Organometallics 1998,
17, 2510.
37, 201.
10 A. Ogawa, J.-i. Kawakami, M. Mihara, T. Ikeda, N.
Sonoda, T. Hirao, J. Am. Chem. Soc. 1997, 119, 12380.
11 A. Ohtaka, H. Kuniyasu, M. Kinomoto, H. Kurosawa,
J. Am. Chem. Soc. 2002, 124, 14324.
12 H. Kuniyasu, K. Takekawa, F. Yamashita, K. Miyafuji, S.
Asano, Y. Takai, A. Ohtaka, A. Tanaka, K. Sugoh, H. Kurosawa,
N. Kambe, Organometallics 2008, 27, 4788.
13 A. Ishii, N. Nakata, R. Uchiumi, K. Murakami, Angew.
Chem., Int. Ed. 2008, 47, 2661.
38 H. Singer, G. Wilkinson, J. Chem. Soc. A 1968, 2516.
39 S. Shoai, P. Bichler, B. Kang, H. Buckley, J. A. Love,
Organometallics 2007, 26, 5778.
40 N. Nakata, N. Furukawa, T. Toda, A. Ishii, Angew. Chem.,
Int. Ed. 2010, 49, 5784.
41 A. S. Goldman, K. I. Goldberg, in Activation and
Functionalization of C-H Bonds in ACS Symposium Series,
ed. by K. I. Goldberg, A. S. Goldman, 2004, Vol. 885, pp. 1-43.
doi:10.1021/bk-2004-0885.ch001.
14 N. Nakata, Y. Yamaguchi, A. Ishii, J. Organomet. Chem.
2010, 695, 970.
15 N. Nakata, T. Yoshino, A. Ishii, Phosphorus, Sulfur Silicon
Relat. Elem. 2010, 185, 992.
16 A. Ishii, Y. Yamaguchi, N. Nakata, Dalton Trans. 2010, 39,
6181.
17 N. Nakata, T. Ikeda, A. Ishii, Inorg. Chem. 2010, 49, 8112.
18 A. Ishii, H. Kamon, K. Murakami, N. Nakata, Eur. J. Org.
Chem. 2010, 1653.
42 A. Ishii, S. Matsubayashi, T. Takahashi, J. Nakayama,
J. Org. Chem. 1999, 64, 1084.
19 A. Ishii, Y. Yamaguchi, N. Nakata, Org. Lett. 2011, 13,
3702.
43 F. Gao, A. H. Hoveyda, J. Am. Chem. Soc. 2010, 132,
10961.
44 G. M. Sheldrick, SHELXL-97, Program for Crystal
Structure Refinement, University of Göttingen, Germany, 1997.
20 C. A. Tolman, Chem. Rev. 1977, 77, 313.
21 L. S. Hegedus, B. C. G. Söderberg, Transition Metals in
the Synthesis of Complex Organic Molecules, 3rd ed., University
Science Books, Sausalito, California, 2010, p. 17.
22 A. M. Trzeciak, T. Glowiak, R. Grzybek, J. J. Ziólkowski,