Synthesis and structures of η1-allenyl and/or -propargyl Pd(II) complexes and their reactivity toward trimethylsilyl pseudohalides, organic thiols, and N-heterocyclic carbene ligands

Article abstract of DOI:10.1016/j.ica.2012.12.011

Facile oxidative additions of various propargyl halides to [Pd(CH ₂CHPh)(PR₃)₂], which could be generated in situ from trans-[PdEt₂(PR₃)₂] (PR ₃PMe₃, PEt₃, PMe₂Ph) and styrene, gave the bis(phosphine) η¹-allenyl and/or η¹- propargyl Pd(II) complexes. The chloro ligand in the η¹-allenyl Pd(II) complex could be replaced by pseudohalides to produce the new corresponding pseudohalo complexes, trans-[XPd(CHCCH₂)(PMe ₃)₂], when treated with trimethylsilyl pseudohalides (Me₃SiX: X = NCS, CN, N₃). The η¹-allenyl complex was also converted into the thiolato complexes when treated with various organic thiols. In addition, the phosphine ligand in the η¹- allenyl complex could be replaced by NHC (N-heterocyclic carbene) to produce η¹-allenyl or -propargyl Pd(II) complex possessing the NHC ligand, depending on the coordinated η¹-allenyl moiety. On the other hand, oxidative addition of phenyl propargyl sulfide to the [Pd(CH ₂CHPh)(PMe₃)₂] gave a phenyl thiolato η¹-allenyl Pd(II) complex, trans-[(C₆H ₅S)Pd(CHCCH₂)(PMe₃)₂].

Full text of DOI:10.1016/j.ica.2012.12.011

Inorganica Chimica Acta 398 (2013) 54–63
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Inorganica Chimica Acta
journal homepage: www.elsevier.com/locate/ica
Synthesis and structures of g
1-allenyl and/or -propargyl Pd(II) complexes
and their reactivity toward trimethylsilyl pseudohalides, organic thiols,
and N-heterocyclic carbene ligands
a
Yong-Joo Kim a, , Hyun-Kyung Kim , Jung-Hyun Lee a,b, Zhen Nu Zheng b, Soon W. Lee b
⇑
a Department of Chemistry, Kangnung-Wonju National University, Gangneung 210-702, Republic of Korea
b Department of Chemistry, Sungkyunkwan University, Natural Science Campus, Suwon 440-746, Republic of Korea
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 23 April 2012
Received in revised form 7 December 2012
Accepted 7 December 2012
Available online 19 December 2012
Facile oxidative additions of various propargyl halides to [Pd(CH2@CHPh)(PR3)2], which could be gener-
ated in situ from trans-[PdEt2(PR3)2] (PR3@PMe3, PEt3, PMe2Ph) and styrene, gave the bis(phosphine) g1
-
allenyl and/or g g
1-propargyl Pd(II) complexes. The chloro ligand in the 1-allenyl Pd(II) complex could be
replaced by pseudohalides to produce the new corresponding pseudohalo complexes, trans-
[XPd(CH@C@CH2)(PMe3)2], when treated with trimethylsilyl pseudohalides (Me3SiX: X = NCS, CN, N3).
The
organic thiols. In addition, the phosphine ligand in the
(N-heterocyclic carbene) to produce
1-allenyl or -propargyl Pd(II) complex possessing the NHC ligand,
depending on the coordinated
1-allenyl moiety. On the other hand, oxidative addition of phenyl prop-
g
1-allenyl complex was also converted into the thiolato complexes when treated with various
Keywords:
g
1-allenyl complex could be replaced by NHC
Allenyl complexes
Propargyl complexes
Trimethylsilyl isothiocyanate
Trimethyl cyanide
Trimethylsilyl azide
Palladium
g
g
argyl sulfide to the [Pd(CH2@CHPh)(PMe3)2] gave a phenyl thiolato
g
1-allenyl Pd(II) complex, trans-
[(C6H5S)Pd(CH@C@CH2)(PMe3)2].
Ó 2012 Elsevier B.V. All rights reserved.
1. Introduction
ligands is needed. In addition, it would be desirable to develop
more efficient synthetic routes to (g
1-allenyl)–Pd(II) complexes.
g
1-Allenyl or -propargyl Pd(II) complexes are one of key inter-
In this work, we investigated oxidative additions of organic ha-
mediates in the Pd-catalyzed C–C coupling reactions or nucleo-
philic substitutions of allyllic or propargyl complexes with
various nucleophiles including thiols [1–5]. Such complexes can
be prepared by oxidative addition of organic allenyl or propargyl
halides to zerovalent palladium complexes [6–9]. Studies on the
lides to [Pd(CH2@CHPh)(PR3)2] (PR3@PMe3, PEt3, PMe2Ph) to pre-
pare new
basic phosphines. We also attempted to synthesize such complexes
by the ligand substitution with trimethylsilyl pseudohalides. The
reactivity of the products toward various organic thiols and NHC
(N-heterocyclic carbene) was examined.
g g
1-allenyl or 1-propargyl Pd(II) complexes possessing
isomeric conversion between the
and Pt(II) complexes were reported [6c,9,10]. In addition, reactions
of the
1-allenyl complexes with organozinc agents [7a], small
g g
1-allenyl and 1-propargyl Pd(II)
2. Experimental
g
molecules such as CO and organic isocyanides (CN–R) [11], alkali
metal carbanions [8], and organic nucleophiles [12] were previ-
ously investigated. Further treatment of these complexes with an-
other zerovalent complex to produce dinuclear Pd complexes,
bridged by an allenyl or propargyl moiety, were also reported
2.1. General, materials, and measurements
All manipulations of air-sensitive complexes were performed
under N2 or Ar by standard Schlenk-line techniques. The analytical
laboratories at Kangnung-Wonju National University carried out
elemental analyses with a CE instruments EA1110. IR spectra were
recorded on a Perkin Elmer BX spectrophotometer. NMR (1H,
13C{1H}, and 31P{1H}) spectra were obtained on a JEOL Lamda 300
and ECA 600 MHz spectrometer. Chemical shifts were referenced
to internal Me4Si or to external 85% H3PO4. Trans-[PdEt2(PMe3)2]
was prepared by the literature method [13b]. IPr (1,3-bis(2,6-diiso-
propylphenyl)imidazol-2-ylidene) was prepared by the literature
method [14] or purchased from Strem or Sejin Chemical.
[7c,10c,d]. However, most g
1-allenyl Pd(II) or Pt(II) complexes in
the above mentioned reactions contain less basic PPh3 ligands as
a supporting ligand. In this context, a systematic investigation of
reactivity of the complexes containing various tertiary phosphine
⇑
Corresponding author. Tel.: +82 33 640 2308; fax: +82 33 640 2264.
E-mail address: yjkim@kangnung.ac.kr (Y.-J. Kim).
0020-1693/$ - see front matter Ó 2012 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.ica.2012.12.011

Y.-J. Kim et al. / Inorganica Chimica Acta 398 (2013) 54–63
55
2
1
2.2. Preparation of trans-[XPd(CH@C@CH2)(PR3)2] (A-type) (1–4) and
trans-[BrPd(CH2C„CR)(PMe3)2] (R = SiMe3, 5; naphthyl, 6)
(t, JPC = 2.2 Hz, CH2), 0.1 (s, Si(CH3)3), 13.6 (t, JPC = 14 Hz,
3
P(CH3)3), 84.5 (t, JPC = 1.8 Hz, C„C–SiMe3), 111.5 (s, C„C–SiMe3).
31P{1H} NMR (120 MHz in CDCl3, d): ꢁ15.9 (s).
To a Schlenk flask containing trans-[PdEt2(PMe3)2] (0.244 g,
0.77 mmol) at 0 °C were added sequentially styrene (0.241 ml,
1.54 mmol) and THF (2 ml). The mixture was heated at 55 °C for
1 h to give a yellow solution. At room temperature, propargyl chlo-
ride (0.061 ml, 0.85 mmol) was added to the mixture, and then the
initial pale yellow solution turned to a yellow solution. After stir-
ring the reaction mixture for 3 h, the solvent was removed com-
pletely under vacuum, and then the resulting oily residue was
solidified with hexane. The solids were filtered and washed with
hexane (1 ml ꢀ 3) to give pale yellow solids, which were recrystal-
lized from excess diethyl ether to give pale yellow solids of trans-
[ClPd(CH@C@CH2)(PMe3)2] (1, 0.181 g, 71%). Anal. Calc. for C9H21-
ClP2Pd: C, 32.45; H, 6.36. Found: C, 32.21; H, 6.36%. IR (KBr,
Trans-[BrPd(CH2C„CR)(PMe3)2] (R = naphthyl, 6, 86%) was pre-
pared analogously. The pure complex 6 could be obtained by re-
peated recrystallizations in excess diethyl ether. Anal. Calc. for
C
19H27BrP2Pd: C, 45.31; H, 5.40. Found: C, 45.42; H, 5.85%. IR
(KBr, cmꢁ1):
m
(C„C) 2174. 1H NMR (CDCl3 in 300 MHz, d): 1.58
2
3
(t, JHP = 3.3 Hz, 18H, PMe3), 2.17 (t, JHP = 7.7 Hz, 2H, CH2), 7.34–
7.53 (m, 4H, Ar), 7.72–7.84 (m, 2H, Ar), 8.29–8.32 (m, 1H, Ar).
13C{1H} NMR (75 MHz, CDCl3, d): ꢁ3.0 (t, JPC = 2.2 Hz, CH2), 14.2
2
1
(t, JPC = 15 Hz, P(CH3)3), 84.5 (s, C„C–C10H7), 100.1 (s, C„C–
C
10H7), 125.4, 126.1, 126.2, 126.3, 127.0, 128.2, 128.6, 128.7,
133.3. 31P{1H} NMR (120 MHz in CDCl3, d): –15.6 (s).
2.3. Preparation of trans-[ClPd(C(Ph)@C@CH2)(PR3)2] (7, PMe3 and 8,
PMe2Ph), trans-[ClPd(CH2C„CPh)(PEt3)2] (9) and trans-[BrPd(C(Me)–
C@C@CH2)(PMe3)2] (10A) and trans-[BrPd(CH2C„C–Me)(PMe3)2]
(10P)
cmꢁ1):
m
(@C@) 1910. 1H NMR (CDCl3 in 300 MHz, d): 1.41 (t,
4
5
2JHP = 3.5 Hz, 18H, PMe3), 4.00 (dt, JHH = 6.6 Hz, JHP = 4.0 Hz, 2H,
@CH2), 5.22 (tt, JHH = 6.6 Hz, JHP = 5.9 Hz, 1H, CH@). 13C{1H}
NMR (75 MHz, CDCl3, d): 13.5 (t, JPC = 15 Hz, P(CH3)3), 65.8
4
3
1
2
3
(s,@CH2), 79.1 (t, JPC = 8.6 Hz, Pd–CH@), 199.5 (t, JPC = 3.7 Hz,
To a Schlenk flask containing trans-[PdEt2(PMe3)2] (0.203 g,
0.64 mmol) at 0 °C were added sequentially styrene (0.200 ml,
1.92 mmol) and THF (2 ml). The mixture was heated at 55 °C for
1 h to give a yellow solution. At room temperature, 3-chloro-1-
phenyl-1-propyne (0.097 ml, 0.71 mmol) was added to the
mixture. After stirring the reaction mixture for 3 h, the solvent
was removed, and then the resulting oily residue was solidified
with hexane. The solids were filtered and washed with hexane
(1 ml ꢀ 3) to give pale yellow solids, which were recrystallized
from excess diethyl ether to give white crystals of trans-
[ClPd(C(Ph)@C@CH2)(PMe3)2] (7, 0.164 g, 63%). Anal. Calc. for
@C@). 31P{1H} NMR (120 MHz in CDCl3, d): ꢁ15.9 (s).
g
1-Allenyl complexes trans-[XPd(CH@C@CH2)(PR3)2] (2–4)
were prepared analogously. Trans-[BrPd(CH@C@CH2)(PMe3)2] (2,
79%): Anal. Calc. for C9H21BrP2Pd: C, 28.63; H, 5.61. Found: C,
28.76; H, 5.77%. IR (KBr, cmꢁ1): (@C@) 1909. 1H NMR (CDCl3 in
m
300 MHz, d): 1.45 (t, 2JHP = 3.7 Hz, 18H, PMe3), 4.02 (dt, 4JHH = 6.6 -
Hz, 5JHP = 4.0 Hz, 2H, @CH2), 5.29 (tt, 4JHH = 6.6 Hz, 3JHP = 5.9 Hz, 1H,
1
CH@). 13C{1H} NMR (75 MHz, CDCl3, d): 14.3 (t, JPC = 15 Hz,
2
P(CH3)3), 65.9 (s, @CH2), 81.5 (t, JPC = 7.8 Hz, Pd–CH), 198.9 (t,
3JPC = 3.4 Hz, @C@). 31P{1H} NMR (120 MHz in CDCl3, d): ꢁ17.5 (s).
Trans-[ClPd(CH@C@CH2)(PEt3)2] (3, 97%): Anal. Calc. for C15H33-
C
15H25ClP2Pd: C, 44.03; H, 6.16. Found: C, 44.15; H, 6.47%. IR
ClP2Pd: C, 43.18; H, 7.97. Found: C, 43.48; H, 8.53%. IR (KBr, cmꢁ1):
(KBr, cmꢁ1):
m
(@C@) 1898. 1H NMR (CDCl3 in 300 MHz, d): 1.31
3
2
5
m
(@C@) 1909. 1H NMR (CDCl3 in 300 MHz, d): 1.15 (qn, JHP = 7.9 -
(t, JHP = 3.7 Hz, 18H, PMe3), 4.37 (t, JHP = 3.5 Hz, 2H, @CH2), 7.11
Hz, 18H, P(CH2CH3)3), 1.82 (m, 12H, P(CH2CH3)3), 3.95 (dt,
(m, 1H, Ph), 7.22 (m, 2H, Ph), 7.67 (m, 2H, Ph). 13C{1H} NMR
5
4
1
4JHH = 6.6 Hz, JHP = 3.7 Hz, 2H,@CH2), 5.22 (tt, JHH = 6.6 Hz,
(75 MHz, CDCl3, d): 13.7 (t, JPC = 15 Hz, P(CH3)3), 68.6 (s,@CH2),
3JHP = 6.2 Hz, 1H, CH@). 13C{1H} NMR (75 MHz, CDCl3, d): 8.0 (s,
98.2 (t, JPC = 8.6 Hz, Pd–C), 126.1, 127.9, 129.0, 140.2 (t, JPC = 2.5
Hz, Ph), 197.4 (s, @C@). 31P{1H} NMR (120 MHz in CDCl3, d):
ꢁ15.3 (s).
2
3
1
P(CH2CH3)3), 14.2 (t, JPC = 13 Hz, P(CH2CH3)3), 65.3 (s, @CH2),
78.5 (t, JPC = 8.0 Hz, Pd–CH), 199.1 (t, JPC = 3.4 Hz, @C@). 31P{1H}
2
3
NMR (120 MHz in CDCl3, d): 14.5 (s).
Complexes 8 and 9 were prepared analogously. Trans-[ClPd
(C(Ph)@C@CH2)(PMe2Ph)2] (8, 91%): Anal. Calc. for C25H29ClP2Pd:
Trans-[ClPd(CH@C@CH2)(PMe2Ph)2] (4, 98%): Anal. Calc. for
C
19H25ClP2Pd: C, 49.91; H, 5.51. Found: C, 50.32; H, 5.84%. IR
C, 56.30; H, 5.48. Found: C, 56.52; H, 5.96%. IR (KBr, cmꢁ1):
(KBr, cmꢁ1):
m
(@C@) 1912. 1H NMR (CDCl3 in 300 MHz, d): 1.72
m
(@C@) 1903. 1H NMR (CDCl3 in 300 MHz, d): 1.60 (dt, JHP = 3.3,
2
(t, JHP = 3.3 Hz, 12H, PMe2Ph), 3.66 (dt, 4JHH = 6.6 Hz, JHP = 3.7 Hz,
47 Hz, 12H, PMe2Ph), 3.87 (t, JHP = 3.1 Hz, 2H, @CH2), 7.00–7.02
2
5
5
4
3
2H,@CH2), 4.91 (tt, JHH = 6.6 Hz, JHP = 5.9 Hz, 1H, CH@), 7.39 (m,
(m, 3H, Ph), 7.26–7.39 (m, 8H, Ph), 7.46–7.53 (m, 4H, Ph). 13C{1H}
4H, Ph), 7.64 (m, 6H, Ph). 13C{1H} NMR (75 MHz, CDCl3, d): 12.6
NMR (75 MHz, CDCl3, d): 12.6 (dt, JPC = 5.6, 15 Hz, P(CH3)2Ph),
1
1
2
2
(t, JPC = 15 Hz, P(CH3)2Ph), 66.1 (s, @CH2), 79.9 (t, JPC = 7.4 Hz,
68.5 (s, @CH2), 98.3 (t, JPC = 5.6 Hz, Pd–C), 125.7, 127.5, 128.1 (t,
2
1
3
Pd–CH), 120.4 (t, JPC = 4.6 Hz, Ph), 129.7, 131.1 (t, JPC = 5.9 Hz,
3JPC = 4.6 Hz, Ph), 129.0, 129.4, 130.7 (t, JPC = 5.6 Hz, Ph), 134.6 (t,
Ph), 134.6, 199.7 (t, JPC = 3.4 Hz, @C@). 31P{1H} NMR (120 MHz
2JPC = 22 Hz, Ph), 139.6 (t, JPC = 2.5 Hz, Ph), 197.8 (t, JPC = 4.6 Hz,
3
4
3
in CDCl3, d): –6.7 (s).
@C@). 31P{1H} NMR (120 MHz in CDCl3, d): ꢁ6.9 (s).
To a Schlenk flask containing trans-[PdEt2(PMe3)2] (0.236 g,
0.75 mmol) at 0 °C were added sequentially styrene (0.233 ml,
2.24 mmol) and THF (2 ml). The mixture was heated at 55 °C for
1 h to give a yellow solution. At room temperature, when 3-bro-
mo-1-(trimethylsilyl)-1-propyne (0.134 ml, 0.82 mmol) was added
to the mixture, the initial pale yellow solution turned to a yellow
solution. After stirring the reaction mixture for 3 h, the solvent
was removed, and the resulting oily residue was solidified with
hexane. The solids were filtered and washed with hexane
(1 ml ꢀ 3) to give pale yellow solids, which were recrystallized
from excess diethyl ether to give pale yellow solids of trans-
[BrPd(CH2C„C–SiMe3)(PMe3)2] (5, 0.231 g, 69%). Anal. Calc. for
Trans-[ClPd(CH2C„CPh)(PEt3)2] (9, 97%): Anal. Calc. for C21H37-
ClP2Pd: C, 51.13; H, 7.56. Found: C, 51.13; H, 7.70%. IR (KBr,
cmꢁ1): (@C@) 2186. 1H NMR (CDCl3 in 300 MHz, d): 1.14 (qn,
m
3JHP = 7.8 Hz, 18H, P(CH2CH3)3), 1.86 (m, 12H, P(CH2CH3)3), 1.93
3
(t, JHP = 3.3 Hz, 2H, CH2), 7.21–7.25 (m, 5H, Ph). 13C{1H} NMR
2
(75 MHz, CDCl3, d): ꢁ8.3 (t, JPC = 3.1 Hz, CH2), 8.2 (s, P(CH2CH3)3),
1
13.8 (t, JPC = 11 Hz, P(CH2CH3)3), 80.7 (s, C„C–Ph), 95.9 (s, C„C–
Ph). 31P{1H} NMR (120 MHz in CDCl3, d): 15.3 (s).
To a Schlenk flask containing trans-[PdEt2(PMe3)2] (0.259 g,
0.81 mmol) at 0 °C were added sequentially styrene (0.255 ml,
2.43 mmol) and THF (2 ml). The mixture was heated at 55 °C for
1 h to give a yellow solution. On addition of 3-bromo-1-methyl-
1-propyne (0.081 ml, 0.89 mmol) to the mixture, and then the ini-
tial pale yellow solution turned to a yellow solution. After stirring
the reaction mixture for 3 h, the solvent was removed, and then the
resulting oily residue was solidified with hexane. The solids were
C
12H29BrP2SiPd: C, 32.05; H, 6.50. Found: C, 32.34; H, 6.97. IR
(KBr, cmꢁ1):
m
(C„C) 2142. 1H NMR (CDCl3 in 300 MHz, d): 0.11
2
(s, 9H, Si(CH3)3), 1.52 (t, JHP = 3.3 Hz, 18H, PMe3), 1.80
(t, JHP = 7.7 Hz, 2H, CH2). 13C{1H} NMR (75 MHz, CDCl3, d): ꢁ3.6
3

56
Y.-J. Kim et al. / Inorganica Chimica Acta 398 (2013) 54–63
filtered and washed with hexane (1 ml ꢀ 3) to give pale yellow sol-
ids, which were recrystallized from excess diethyl ether to give
pale yellow solids of trans-[BrPd(C(Me)–C@C@CH2)(PMe3)2] (10A)
and trans-[BrPd(CH2C„C–Me)(PMe3)2] (10P) in the ratio of
60:40. trans-[BrPd(C(Me)–C@C@CH2)(PMe3)2]: 1H NMR (CDCl3 in
300 MHz, d): 1.51 (t, 2JHP = 3.3 Hz, 18H, PMe3), 1.80 (t, 4JHP = 2.9 Hz,
diethyl ether gave white crystals of trans-[(N3)Pd(CH@C@CH2)-
(PEt3)2] (14, 0.551 g, 86%). Anal. Calcd. for C15H33N3P2Pd: C,
42.51; H, 7.85; N, 9.91. Found: C, 42.27; H, 7.91; 9.84%. IR (KBr,
cmꢁ1):
m
(@C@) 1909,
m
(N3) 2037. 1H NMR (CDCl3 in 300 MHz, d):
1.14 (qn, 4J = 7.9 Hz, 18H, P(CH2CH3)3), 1.82 (m, 12H, P(CH2CH3)3),
4
5
4
3.95 (dt, JHH = 6.6 Hz, JHP = 4.0 Hz, 2H, @CH2), 5.21 (tt, JHH
=
5
5
3
3H, CH3), 3.98 (dq, JHH = 3.3 Hz, JHP = 2.9 Hz, 2H, CH2). 31P{1H}
6.6 Hz, JHP = 6.2 Hz, 1H, CH@). 13C{1H} NMR (75 MHz, CDCl3, d):
1
NMR (120 MHz in CDCl3, d): ꢁ16.0 (s). Trans-[BrPd(CH2C„C–
8.1 (s, P(CH2CH3)3), 14.2 (t, JPC = 13 Hz, P(CH2CH3)3), 65.3
2
2
3
Me)(PMe3)2]: 1H NMR (CDCl3 in 300 MHz, d): 1.46 (t, JHP = 3.3 Hz,
(s,@CH2), 78.5 (t, JPC = 8.0 Hz, Pd–CH), 199.1 (t, JPC = 3.4 Hz,
18H, PMe3), 1.51(overlap, 2H, CH2), 1.72 (s, 3H, CH3). 31P{1H} NMR
(120 MHz in CDCl3, d): ꢁ17.0 (s).
@C@). 31P{1H} NMR (120 MHz in CDCl3, d): 14.5 (s).
2.5. Reactions of trans-[ClPd(CH@C@CH2)(PMe3)2] with RSH
2.4. Reactions of trans-[ClPd(CH@C@CH2)(PR3)2] (1, PMe3; 3, PEt3)
(R = C6H5, C6H5CH2, C6H4–SH)
with Me3Si–X (X = NCS, CN, N3)
To a Schlenk flask containing complex 1 (0.128 g, 0.33 mmol)
were added THF (3 ml) and C6H5SH (0.035 ml, 0.34 mmol). After
stirring for 3 h at room temperature, the resulting orange solution
was evaporated, and the oily residue was solidified with n-hexane.
The solids were filtered and washed with hexane (3 ꢀ 2 ml).
Recrystallization from a diethyl ether gave orange crystals of
trans-[ClPd(SC6H5)(PMe3)2] (15, 0.240 g, 99%). Anal. Calc. for
To a Schlenk flask containing 1 (0.041 g, 0.12 mmol) were added
THF (2 ml) and Me3Si–NCS (0.052 ml, 0.37 mmol). After stirring for
3 h at room temperature, the resulting yellow solution was evapo-
rated, and then the oily residue was solidified with n-hexane. The
solids were filtered and washed with hexane (2 ꢀ 2 ml). Recrystal-
lization from excess diethyl ether gave white crystals of trans-
[(SCN)Pd(CH@C@CH2)(PMe3)2] (11, 0.020 g, 46%). Anal. Calc. for
C10H21NP2SPd: C, 33.77; H, 5.95; N, 3.94. Found: C, 33.30; H,
C
12H23ClP2SPd: C, 35.75; H, 5.75. Found: C, 35.74; H, 5.84%. 1H
2
NMR (CDCl3 in 300 MHz, d): 1.41 (t, JHP = 3.6 Hz, 18H, PMe3),
6.30; N, 3.50%. IR (KBr, cmꢁ1):
m
(@C@) 1913;
m
(NCS) 2100. 1H
6.93 (m, 1H, Ph), 7.04 (m, 2H, Ph), 7.56 (m, 2H, Ph). 13C{1H} NMR
1
NMR (CDCl3 in 300 MHz, d): 1.41 (br, 18H, PMe3), 4.03 (dt,
(75 MHz, CDCl3, d): 13.3 (t, JPC = 16 Hz, P(CH3)3), 122.3, 127.8,
4JHH = 6.6 Hz, JHP = 4.0 Hz, 2H,@CH2), 5.06 (br, 1H, CH@). 13C{1H}
130.5, 145.8 (s, Ph). 31P{1H} NMR (120 MHz in CDCl3, d): ꢁ12.3 (s).
Trans-[ClPd(SCH2C6H5)(PMe3)2] (16) was prepared analogously.
Trans-[ClPd(SCH2C6H5)(PMe3)2] (16, 93%): Anal. Calc. for C13H25-
ClP2SPd: C, 37.42; H, 6.04. Found: C, 37.42; H, 6.43%. 1H NMR
5
1
NMR (75 MHz, CDCl3, d): 13.5 (t, JPC = 15 Hz, P(CH3)3), 66.1 (s,
@CH2), 76.1 (br, Pd–CH), 136.5 (s, NCS), 200.4 (br, @C@). 31P{1H}
NMR (120 MHz in CDCl3, d): ꢁ14.6 (s).
2
To a Schlenk flask containing 1 (0.200 g, 0.60 mmol) were added
THF (3 ml) and Me3Si–CN (0.240 ml, 1.80 mmol). After stirring for
3 h at room temperature, the resulting yellow solution was evapo-
rated, and then the oily residue was solidified with n-hexane. The
solids were filtered and washed with hexane (2 ꢀ 2 ml). Recrystal-
lization from excess diethyl ether gave white crystals of trans-
[(NC)Pd(CH@C@CH2)(PMe3)2] (12, 0.190 g, 98%). Anal. Calc. for
(CDCl3 in 300 MHz, d): 1.51 (t, JHP = 3.6 Hz, 18H, PMe3), 3.46 (s,
2H, CH2), 7.16 (m, 1H, Ph), 7.27 (m, 2H, Ph), 7.35 (m, 2H, Ph).
13C{1H} NMR (75 MHz, CDCl3, d): 13.4 (br, P(CH3)3), 36.2 (s, CH2),
126.1, 128.4, 143.7 (s, Ph). 31P{1H} NMR (120 MHz in CDCl3, d):
ꢁ13.6 (s).
To a Schlenk flask containing complex 1 (0.160 g, 0.48 mmol)
were added THF (3 ml) and HS–C6H4–SH (0.034 g, 0.24 mmol).
After stirring for 3 h at room temperature, the resulting orange sol-
ids were washed with n-hexane. Recrystallization from CH2Cl2/
C
10H21NP2Pd: C, 37.11; H, 6.54; N, 4.33. Found: C, 37.12; H, 6.99;
N, 4.42%. IR (KBr, cmꢁ1):
m(@C@) 1905;
m
(CN) 2123. 1H NMR (CDCl3
4
in 300 MHz, d): 1.43 (br, 18H, PMe3), 3.75 (dt, JHH = 6.6 Hz,
hexane gave orange crystals of trans,trans-[Pd(PMe3)2Cl]2(l-SC6H4-
5JHP = 4.0 Hz, 2H,@CH2), 4.98 (m, 1H, CH@). 13C{1H} NMR
S) (17, 0.157 g, 90%): Anal. Calc. for C18H40Cl2P4S2Pd2: C, 29.69; H,
1
(75 MHz, CDCl3, d): 15.0 (t, JPC = 16 Hz, P(CH3)3), 62.6 (s, @CH2),
5.54. Found: C, 30.46; H, 5.79%. 1H NMR (CDCl3 in 300 MHz, d):
2
2
2
82.6 (t, JPC = 8.1 Hz, Pd–CH), 138.9 (t, JPC = 18 Hz, CN), 200.5 (br,
1.33 (t, JHP = 3.3 Hz, 36H, PMe3), 7.20 (s, 4H, Ph). 13C{1H} NMR
1
@C@). 31P{1H} NMR (120 MHz in CDCl3, d): ꢁ15.2 (s).
(75 MHz, CDCl3, d): 13.3 (t, JPC = 16 Hz, P(CH3)3), 130.6, 139.0 (s,
To a Schlenk flask containing complex 1 (0.190 g, 0.57 mmol)
were added THF (3 ml) and Me3Si–N3 (0.225 ml, 1.71 mmol). After
stirring for 3 h at room temperature, the resulting yellow solution
was completely evaporated, and then the oily residue was solidi-
fied with n-hexane. The solids were filtered and washed with hex-
ane (2 ꢀ 2 ml). Recrystallization from excess diethyl ether gave
white crystals of trans-[(N3)Pd(CH@C@CH2)(PMe3)2] (13, 0.150 g,
Ph). 31P{1H} NMR (120 MHz in CDCl3, d): ꢁ12.4 (s).
2.6. Reactions of trans-[ClPd(CH@C@CH2)(PMe3)2] (1) and trans-
[ClPd{(Ph)C@C@CH2)(PMe3)2}] (7) with NHC (IPr)
To a Schlenk flask containing 1 (0.170 g, 0.51 mmol) was added
IPr (0.198 g, 9.51 mmol) dissolved in THF (6 ml). After stirring the
reaction mixture for 3 h at room temperature, the solvent was
completely removed. To the resulting oily residue was added a
diethyl ether/n-hexane (3:1) solution and then stored in the free-
zer to give crude solids. The solids were filtered, washed with hex-
ane (2 ml ꢀ 2), and recrystallized from diethyl ether to give white
crystals of [ClPd(IPr)(CH@C@CH2)(PMe3)], (18, 0.291 g, 88%). Anal.
Calc for C33H48ClN2PPd: C, 61.39; H, 7.49; N, 4.34. Found: C,
77%). IR (KBr, cmꢁ1): (N3) 2036. 1H NMR (CDCl3
m(@C@) 1910; m
2
in 300 MHz, d): 1.14 (t, JHP = 3.5 Hz, 18H, PMe3), 4.00 (dt,
5
3
4JHH = 6.6 Hz, JHP = 4.0 Hz, 2H, @CH2), 5.22 (tt, JHP = 5.9 Hz, 1H,
CH@). 13C{1H} NMR (75 MHz, CDCl3, d): 13.5 (t, JPC = 15 Hz,
1
2
P(CH3)3), 65.8 (s, @CH2), 79.1 (t, JPC = 8.6 Hz, Pd–CH), 199.5 (t,
3JPC = 3.7 Hz, @C@). 31P{1H} NMR (120 MHz in CDCl3, d): –15.9 (s).
In spite of several recrystallizations, the pure analytical data could
not be obtained due to quite a similar solubility of this complex
and [ClPd(N3)(PMe3)2], and the observed peak integration ratio of
31P{1H} NMR spectrum was 90:10.
60.95; H, 7.94; N, 4.29%. IR (KBr, cmꢁ1):
m
(@C@) 1916. 1H NMR
2
(300 MHz, CDCl3, d): 1.10 (d, JHP = 9.5 Hz, 9H, P(CH3)3), 1.11 (d,
2JHH = 6.6 Hz, 12H, CH(CH3)2), 1.42 (d, JHH = 6.6 Hz, 12 H,
2
2
To a Schlenk flask containing complex 3 (0.633 g, 1.52 mmol)
were added THF (6 ml) and Me3Si–N3 (0.598 ml, 4.54 mmol). After
stirring for 3 h at room temperature, the resulting yellow solution
was completely evaporated, and then the oily residue was solidi-
fied with diethyl ether at ꢁ34 °C. The solids were filtered and
washed with hexane (2 ꢀ 2 ml). Recrystallization from excess
CH(CH3)2), 3.13 (sep, JHH = 6.6 Hz, 4 H, CH(CH3)2), 3.63 (dd,
5
4
4JHH = 6.6 Hz, JHP = 3.3 Hz, 2H, @CH2), 4.54 (dt, JHH = 6.6 Hz,
3
3JHP = 2.2 Hz, 1H, @CH), 7.05 (d, JHH = 1.5 Hz, 2H, @CH), 7.28 (m,
3H, Ar–H), 7.44 (m, 3 H, Ar–H). 13C{1H} NMR (75 MHz, CDCl3, d):
13.3 (d, 1JPC = 29 Hz, P(CH3)3), 23.2 (s, CH(CH3)2), 25.9 (s, CH(CH3)2),
2
28.6 (s, CH(CH3)2), 64.6 (s, @CH2), 77.9 (d, JPC = 9.9 Hz, Pd–CH),

Y.-J. Kim et al. / Inorganica Chimica Acta 398 (2013) 54–63
57
123.5 123.6, 123.7, 129.4, 136.1, 145.9 (s, Ar), 181.7 (d, 2JPC = 168 -
collected with a Bruker Smart APEX2 diffractometer equipped with
a Mo X-ray tube. Collected data were corrected for absorption with
SADABS based upon the Laue symmetry by using equivalent reflec-
tions [15]. All calculations were carried out with SHELXTL programs
[16]. All structures were solved by direct methods. All non-
hydrogen atoms were refined anisotropically, and all hydrogen
atoms were positioned in ideal positions and refined in a riding
model.
3
Hz, NCN), 200.1 (d, JPC = 5.6 Hz, @C@). 31P{1H} NMR (120 MHz in
CDCl3, d): ꢁ15.0 (s).
To a Schlenk flask containing complex 7 (0.224 g, 0.55 mmol)
was added IPr (0.213 g, 0.55 mmol) in THF (5 ml). After stirring
the reaction mixture for 3 h at room temperature, the solvent
was completely removed. To the resulting oily residue was added
a diethyl ether/n-hexane (2:4) solution and then stored in the free-
zer to give crude solids. The solids were filtered, washed with hex-
ane (2 ml ꢀ 2), and recrystallized from (diethyl ether)/hexane to
give yellow crystals of [ClPd(IPr)(CH2C„CPh)(PMe3)], (19,
0.328 g, 83%). Anal. Calc. for C39H52ClN2PPd: C, 64.90; H, 7.27; N,
3. Results and discussion
3.88. Found: C, 64.87; H, 7.68; N, 3.84%. IR (KBr, cmꢁ1):
m
(C„C)
3.1. Preparation of g
1-allenyl and/or -propargyl Pd(II) complexes
2
2184. 1H NMR (300 MHz, CDCl3, d): 1.12 (d, JHH = 6.6 Hz, 12H,
CH(CH3)2), 1.20 (d, 2JHP = 9.5 Hz, 9H, P(CH3)3), 1.44 (d, 2JHH = 6.6 Hz,
Oxidative addition of propargyl halides (XCH2C„CH) to the Pd–
alkene complex, [Pd(CH2@CHPh)(PR3)2] [13] gave the
1-allenyl
Pd(II) complexes, trans-[XPd(C@C@CH2)(PR3)2] (A-type) (1–4), or
the
1-propargyl Pd(II) complexes, trans-[BrPd(CH2C„CR)(PMe3)2]
3
12H, CH(CH3)2), 1.46 (d, JHP = 5.5 Hz, 2 H, CH2), 2.88 (br, 4H,
g
CH(CH3)2), 3.32 (br, 4H, CH(CH3)2), 7.03–7.38 (m, 11H, Ar–H). The
1H signal of CH in the heterocyclic ring was overlapped to the
g
2
aromatic signals. 13C{1H} NMR (75 MHz, CDCl3, d): ꢁ9.7 (d, JPC
=
(P-type) (R = SiMe3, 5; naphthyl, 6), depending on the identity of
organic halides and supporting ligands (Scheme 1). In a similar
way, ClCH2C„C–Ph oxidatively adds to [Pd(CH2@CHPh)(PR3)2]
1
1.9 Hz, CH2), 12.9 (d, JPC = 27 Hz, P(CH3)3), 23.2 (s, CH2), 26.1 (s,
3
CH(CH3)2), 28.7 (s, CH(CH3)2), 31.6 (s, CH(CH3)2), 78.7 (d, JPC = 3.7
Hz, C„C–Ph), 98.5 (d, JPC = 2.7 Hz, C„C–Ph), 123.6 123.7, 125.7,
(PR3@PMe3, PMe2Ph) to produce the g
1-allenyl complexes trans-
4
2
126.5, 127.8, 129.6, 130.6, 130.7, 146.5 (s, Ar), 184.6 (d, JPC = 159
[ClPd{C(Ph)@C@CH2}(PR3)2] (7 and 8) (Scheme 2). In contrast, the
Hz, NCN). 31P{1H} NMR (120 MHz in CDCl3, d): ꢁ13.2 (s).
To a Schlenk flask containing the PMe3–NHC–Pd(0) complex
[(Me3P)Pd(NHC)] (NHC = IPr) (0.340 g, 0.59 mmol) were added
same reaction involving the PEt3 analog [Pd(CH2@CHPh)(PEt3)2]
exclusively gave the
(CH2C„CPh)(PEt3)2] (9).
The IR spectra of the products clearly show characteristic bands
at 1898–1912 cmꢁ1 for 1-allenyl (1–4 and 7–8) or at
(@ꢂ@) of the
2142–2186 cmꢁ1 for 1-propargyl group (5–6 and
(C„C) of the
9). 1H NMR peaks due to the CH and CH2 in the 1-CH@C@CH2
(or
1-CH2C„CR) ligands are consistent with those in the literature
data [6–9]. The carbon signal (@ꢂ@) in the
1-allenyl ligand of the
above complexes appears at ca. 197–199 ppm in the 13C{1H}
NMR spectra and also proves its existence. Interestingly, g1
g
1-propargyl Pd(II) complex trans-[ClPd
diethyl ether (5 ml) and propargyl chloride (47 ll, 0.65 mmol) at
0 °C. After stirring the reaction mixture for 1 h at room tempera-
ture, the solvent was completely removed. To the resulting oily
residue was added n-hexane to give crude solids. The solids were
filtered and recrystallized from n-hexane to give white crystals of
[ClPd(IPr)(CH@C@CH2)(PMe3)], (18, 0.272 g, 71%). Its identity was
confirmed by comparing its 1H and 31P NMR spectra with those
of the ligand-substitution product.
m
g
m
g
g
g
g
-
The analogous reaction of [(Me3P)Pd(NHC)] (NHC = IPr) with an
equivalent of 3-chloro-1-phenyl-1-propyne gave the product
[ClPd(IPr)(CH2C„CPh)(PMe3)] (19, 0.118 g, 66%). The 1H and 31P
NMR data of the product were compared with those of the li-
gand-substitution product.
propargyl complexes 5, 6, and 9 show upfield shifts of the carbon
atom (Pd–CH2) at d ꢁ3.6, ꢁ3.0 ppm (2JPC = 2.2 Hz), and ꢁ8.3 ppm
2.7. Reaction of [Pd(styrene)(PMe3)2] with C6H5S–CH2C„CH
To a Schlenk flask containing trans-[PdEt2(PMe3)2] (0.266 g,
0.84 mmol) at 0 °C were added sequentially styrene (0.289 ml,
2.52 mmol) and THF (3 ml). The mixture was heated at 55 °C for
1 h to give a yellow solution. At room temperature, on addition
of phenyl propargyl sulfide (0.122 ml, 0.89 mmol) to the mixture,
the initial pale yellow solution turned to a yellow solution. After
stirring the reaction mixture for 3 h, the solvent was removed,
and then the resulting oily residue was solidified with hexane.
The solids were filtered and washed with hexane (1 ml ꢀ 3) to give
pale yellow solids, which were recrystallized from diethyl ether to
produce yellow crystals of trans-[(C6H5S)Pd(CH@C@CH2)(PMe3)2]
(20, 0.208 g, 59%). Anal. Calc. for C15H26P2SPd: C, 44.29; H, 6.44.
Scheme 1.
Found: C, 44.45; H, 6.75%. IR (KBr, cmꢁ1):
m
(@C@) 1906. 1H NMR
2
(CDCl3 in 300 MHz, d): 1.34 (t, JHP = 3.3 Hz, 18H, PMe3), 3.88 (dt,
4JHH = 6.6 Hz, JHP = 3.7 Hz, 2H,@CH2), 5.29 (tt, JHH = 6.6 Hz,
5
4
3JHP = 5.1 Hz, 1H, CH@). 13C{1H} NMR (75 MHz, CDCl3, i): 13.8 (t,
1JPC = 15 Hz, P(CH3)3), 63.2 (s,@CH2), 83.7 (t, JPC = 9.9 Hz, Pd–CH),
2
3
3
121.2, 127.4, 132.1, 149.2 (t, JPC = 1.2 Hz, Ph), 199.2 (t, JPC = 3.4
Hz,@C@). 31P{1H} NMR (120 MHz in CDCl3, d): ꢁ15.6 (s).
2.8. X-ray structure determination
Single crystals of 8, 9, 11, 15 and 19 for X-ray crystallography
were grown from diethyl ether at ꢁ35 °C. All X-ray data were
Scheme 2.

58
Y.-J. Kim et al. / Inorganica Chimica Acta 398 (2013) 54–63
(2JPC = 3.1 Hz), respectively. Wojcicki and co-workers [17a] previ-
ously reported the closely related complex trans-[PtCl{CH2-
C„CPh}(PPh3)2], whose 13C NMR spectrum displays the Pt–CH2
peak at d ꢁ5.5 ppm (JPC = 3.9 Hz), practically the same value as
those found for complexes 5, 6, and 9. At this point, we speculate
that a combination of the electronegative trans Cl or Br group
and the aryl alkynyl group nearly perpendicular to the molecular
plane (see ORTEP drawing of 9 in Fig. 2), which is known as a better
donor ligand than halide, might shield the Pd–CH2 carbon to result
in such an upfield shift. A singlet in the 31P NMR data of the com-
plexes strongly supports the trans conformation of complexes 1–9.
NMR studies for complexes 1–9 except 6 indicates no equilib-
by NMR spectroscopy (Scheme 3). However, we could not separate
it due to their similar solubility.
When a mixture of 10A and 10P is heated to 80 °C in toluene,
the isomerization between
g g
1-allenyl and 1-propargyl Pd(II)
complex or other stereo isomerization (trans to cis) is not observed.
This result may stem from the strong basicity of PMe3 in complexes
10A and 10P. In other words, our PMe3-coordinated
1-propargyl Pd(II) complexes compared to the PPh3-coordinated
Pd(II) complexes do not allow the interconversion between g1
allenyl and
1-propargyl Pd(II) complexes by phosphine dissocia-
tion to form an intermediate such as an
3-allenyl complex to
g
1-allenyl and
g
-
g
g
produce the isomer. This result is quite contrast to a couple of
known isomerizations, including (1) an isomerization of trans-
[XPt(CH2C„CPh)(PPh3)2] to trans-[XPt{C(Ph)@C@CH2}(PPh3)2]
rium between
data contrast with the previously reported NMR data that show an
equilibrium product mixture of the
1-allenyl and 1-propargyl
g g
1-allenyl and 1-propargyl Pd(II) complexes. These
g
g
(X = Cl, Br), an (g
1-propargyl) ? allenyl platinum isomerization,
Pd(II) complexes in the ratio of 75:25, when [Pd(PPh3)4] reacted
under thermal conditions observed by Kurosawa and
co-workers [10a], (2) a cis ? trans isomerization of cis-[BrPt(CH2-
C„CPh)(PPh3)2] under thermal conditions reported by Wojicki
and co-workers [17a], and (3) a trans ? cis isomerization of
trans-[PdBr(C@C@CRR0)(PPh3)2] (R = Me, n-C5H11, t-Bu; R0 = Me, H,
Me, Et; R = R0 = (CH2)5) at room temperature observed by Elsevier
co-workers [7c].
with ClCH2C„C–Ph [9a]. However, 1H and 31P{1H} NMR data of ini-
tially isolated 6 show a mixture of
Pd(II) complexes in the ratio of 14:86, but the pure
g
1-allenyl and
g
g
1-propargyl
1-propargyl
complex trans-[BrPd(CH2C„CR)(PMe3)2] (R = naphthyl, 6) can be
obtained by repeated recrystallizations. In contrast, it should be
mentioned that reactions of [Pd(CH2@CHPh)(PMe3)2] with 1 equiv
of BrCH2C„C–Me in THF or n-hexane produced a mixture of the
In case of propargyl halides (XCH2C„CH; X = Cl, Br), g
1-allenyl
g
1-allenyl complex, trans-[BrPd{C(Me)@C@CH2}(PMe3)2] (10A),
Pd(II) complexes (1–4) in Scheme 1 are selectively obtained.
However, similar reactions of Pd(0) complexes with several prop-
argyl halides containing substituents (XCH2C„C–R; R = Ph, SiMe3,
and the
g
1-propargyl Pd(II) complex, trans-[BrPd(CH2-
C„CMe)(PMe3)2] (10P) in the ratio of 60:40, which was confirmed
naphthyl, Me) produced various
g g
1-allenyl or/and 1-propargyl
complexes, depending on the substituents as well as supporting
phosphine ligands. For example, Scheme 2 shows the formation
of sole allenyl (7 and 8) or g
1-propargyl (9) Pd(II) complexes when
ClCH2C„C–Ph is treated, depending on the phosphine ligands. In
spite of limited information, these results suggest that the relative
steric bulk (cone angle) of phosphine ligands (PMe3 < PMe2Ph <
PEt3) may play an important role in directing the selective
g g
1-allenyl or 1-propargyl Pd(II) complex. By
Scheme 3.
formation of the
Fig. 1. ORTEP drawing of complex 8 showing the atom-labeling scheme and 50% probability thermal ellipsoids. Selected bond lengths (Å) and angles (°): Pd1–C1 2.027(2),
Pd1–P2 2.3053(7), Pd1–P1 2.3079(7), Pd1–Cl1 2.3780(7), C1–C8 1.290(4), C1–C2 1.491(3), C8–C9 1.307(5); C1–Pd1–P2 88.84(8), C1–Pd1–P1 87.66(8), P2–Pd1–P1 172.11(2),
C1–Pd1–Cl1 177.36(7), C8–C1–C2 121.3(2), C8–C1–Pd1 117.3(2), C2–C1–Pd1 121.5(2), C1–C8–C9 177.7(5).

Y.-J. Kim et al. / Inorganica Chimica Acta 398 (2013) 54–63
59
Fig. 2. ORTEP drawing of complex 9. Selected bond lengths (Å) and angles (°): Pd1–C1 2.071(2), Pd1–P2 2.3176(5), Pd1–P1 2.3207(5), Pd1–Cl1 2.3919(5), C1–C2 1.449(3), C2–
C3 1.193(3); C1–Pd1–P2 91.83(6), C1–Pd1–P1 91.80(6), P2–Pd1–P1 174.19(2), C1–Pd1–Cl1 178.80(5), C2–C1–Pd1 108.3(1), C3–C2–C1 178.1(2).
contrast, Kurosawa and co-workers previously reported that
Pd(PPh3)4 reacts with ClCH2C„C–Ph to afford a mixture of g1
allenyl and
1-propargyl Pd(II) complexes in the ratio of 75:25
(5), is only obtained when BrCH2C„C–SiMe3 is used (Scheme 1).
This is consistent with the case of trans-[ClPd(CH2C„CSiMe3)-
(PPh3)2] [9a]. Therefore, we believe that the basicity or steric bulk
of phosphine ligands as well as electronic properties of propargyl
halides based on the substituent may work together in the selec-
tive formation of the products.
-
g
[9a]. Scheme 3 shows the formation of a similar mixture when
[Pd(CH2@CHPh)(PMe3)2] is treated with BrCH2C„C–Me. It should
be worth noting that a single product, g
1-propargyl Pd(II) complex
Table 1
X-ray data collection and structure refinement for complexes 8, 9, 11, 15 and 19.
Complex
8
9
11
15
19
Empirical formula
Formula weight
T (K)
Crystal system
Space group
a (Å)
C
25H29ClP2Pd
C21H37ClP2Pd
493.30
296(2)
monoclinic
P21/c
12.1748(5)
14.5911(6)
14.2045(6)
90
100.889(2)
90
2477.9(2)
4
C10H21NP2PdS
355.68
296(2)
monoclinic
P21/c
8.6682(1)
9.8587(2)
18.9137(3)
90
95.411(1)
90
1609.11(5)
4
C12H23ClP2PdS
403.16
296(2)
monoclinic
P21/c
14.0682(6)
11.0519(4)
11.8852(5)
90
107.039(2)
90
1766.8(1)
4
C39H52ClN2PPd
721.65
296(2)
monoclinic
P21/n
12.7346(3)
15.8979(3)
19.2990(4)
90
98.601(1)
90
3863.2(1)
4
533.27
296(2)
triclinic
ꢀ
P1
9.2242(3)
9.4337(3)
15.2031(4)
89.970(1)
81.774(1)
74.289(1)
1259.41(7)
2
b (Å)
c (Å)
a
(°)
b (°)
c
(°)
V (Å3)
Z
Dcal (g cmꢁ3
)
1.406
0.979
1.322
0.988
1.468
1.457
1.516
1.481
1.241
0.618
l
(mmꢁ1
)
F(000)
544
1024
720
816
1512
Tmax
Tmin
0.9085
0.8135
1.35–28.35
17602
6031
0.8906
0.7427
1.70–28.29
42303
6110
0.8446
0.6691
2.16–28.31
28739
3992
0.8660
0.6649
1.51–28.37
29877
4381
0.9185
0.8460
1.67–28.39
99016
9593
h range (°)
No. of reflections collected
No. of reflections independent
No. of reflections with I > 2
r(I)
5301
4820
3275
3614
7070
Number of parameters
270
0.787
226
0.364
148
0.541
3614
0.503
397
0.515
Max., in
Min., in
D
q
(e Åꢁ3
)
)
D
q
(e Åꢁ3
ꢁ0.334
ꢁ0.253
ꢁ0.513
ꢁ0.422
ꢁ0.513
Goodness-of-fit GOF on F2
1.059
1.027
1.039
1.033
1.029
Ra
0.0321
0.0751
0.0250
0.0530
0.0245
0.0573
0.0284
0.0654
0.0336
0.0733
b
wR2
P
P
a
R = [|Fo| ꢁ |Fc|]/ |Fo|].
P
P
b
2
wR2
=
[w(Fo ꢁ Fc2)2]/ [w(Fo2)2]1/2
.

60
Y.-J. Kim et al. / Inorganica Chimica Acta 398 (2013) 54–63
Scheme 4.
Molecular structures of complexes 8 and 9 are given in Figs. 1
involving 3 equiv or excess Me3Si–N3 gave a mixture of trans-[(N3-
)Pd(CH@C@CH2)(PMe3)2](13) and [PdCl(N3)(PMe3)2] in the ratio of
90:10, which was determined by peak integration of 31P{1H} NMR
spectra. However, the similar treatment with NaN3 in the presence
of water gave unidentꢁified materials, probably due to the nucleo-
philic attack of the N3 at the allenyl moiety. In addition, the sim-
ilar reaction of trans-[ClPd(CH@C@CH2)(PEt3)2] (3) with Me3SiN3
selectively gives the ligand-substitution complex, trans-[(N3)-
Pd(CH@C@CH2)(PEt3)2] (14), as a sole product.
and 2, respectively. Crystal refinement data are listed in Table 1.
To our best knowledge, these structures represent the first
molecular structures of
complexes. The ORTEP drawings for 8 and 9 clearly show a
square-planar geometry containing
1-allenyl group or 1-propar-
gyl group around the Pd center, respectively. The
1-allenyl group
g g
1-allenyl or 1-propargyl palladium(II)
g
g
g
for 8 is nearly perpendicular to the molecular plane with the dihe-
dral angle of 89.59(7)°, which is similar to those reported for a
number of
g
1-allenyl Pt(II) complexes [7c,12,17b]. The allenyl
The substitution of the chloro ligand by the pseudohalogen
groups can be easily monitored by looking at the appearance of
group C1–C8–C9 is linear (177.7(5)°), and the bond distances
of C1–C8 and C8–C9 (1.290(4) and 1.307(5) Å) are close to those
characteristic of pseudohalogen bands at 2036 for
2100 cmꢁ1 for (NCS) or at 2119 cmꢁ1 for
(CN) in IR spectra, in
addition to the change in the allenyl spectra at 1905–1912 cmꢁ1
m(N3), at
in the
g
1-allenyl Pt(II) complexes. The Pd–C bond length
m
m
(2.027(2) Å) of 8 is close to those of trans-[PtBr(CH@C@CH2)-
(PPh3)2] [12] (2.040(5) Å), trans-[PtBr(CH@C@CMe2)(PPh3)2] [7c]
(2.10(3) Å), and [(PMe3)3Pt(C(Ph)@C@CH2)](BPh4) [17b] (2.084(9)
and 2.090(9) Å). The bond angle, Pd–C1–C8 (117.3(2)°) is smaller
than those of trans-[PtBr(CH@C@CH2)(PPh3)2] (126.2(5)°), trans-
[PtBr(CH@C@CMe2)(PPh3)2] (131(4)°), and [(PMe3)3Pt(C(Ph)@
C@CH2)](BPh4) (121.2(7)° and (118.4(7)°). The molecular structure
.
of 9 in Fig. 2 also clearly indicates the formation of
Pd(II) complex. The Pd1–C1 bond length (2.071(2) Å) is typical of
the Pd–C(sp3)
-bond length [18]. The C2–C3 bond length
g
1-propargyl
r
(1.193(3) Å) in the propargyl fragment also falls in the range
1.181–1.195 Å, typically observed for the organic C„C–C (sp2,
aromatic) fragments [19].
3.2. Reactivity toward trimethylsilyl pseudohalides, Me3S–X (X = NCS,
CN, N3) and organic thiols R–SH (R = Ph, CH2Ph, C6H4–SH)
Insertion of small molecules such as isocyanides or CO into the
M–C bond is one of the fundamental steps in the late transition
metal-catalyzed synthesis of organic unsaturated compounds
[20–22]. Considering this reactivity, a similar reactivity may occur
for the (
-allenyl metal complexes can behave as important starting
materials or precursors for the aforementioned reactions. In this
context, the reactivity of the allenyl moiety of the
1-allenyl Pd(II)
r-allenyl)–Pd or –Pt bonds. If this reactivity occurs, the
r
g
complexes toward trimethylsilyl pseudohalides (Me3SiX: X = NCS,
CN, N3) was investigated. First, the reaction of complex 1 with 3
equiv of trimethylsilyl isothiocyanate (Me3Si–NCS) readily
undergoes to give the iosthiocyanato allenyl complex trans-
[(SCN)Pd(CH@C@CH2)(PMe3)2] (11, 46%) by ligand replacement.
Similarly, the chloride substitution with 3 equiv of Me3Si–CN also
produces the cyanato allenyl complex trans-[(NC)Pd(CH@C@CH2)-
(PMe3)2] (12, 98%), as shown in Scheme 4. In contrast, the reaction
Fig. 3. ORTEP drawing of complex 11. Selected bond lengths (Å) and angles (°): Pd1–
C2 2.010(2), Pd1–N1 2.058(2), Pd1–P1 2.3108(6), Pd1–P2 2.3116(6), S1–C1
1.632(3), N1–C1 1.149(3); C2–C3 1.284(4), C3–C4 1.295(4); C2–Pd1–N1
179.04(9),C2–Pd1–P1 86.77(7), N1–Pd1–P1 93.96(6), P1–Pd1–P2 172.69(2), N1–
C1–S1 179.6(2), C2–C3–C4 178.6(3).

Y.-J. Kim et al. / Inorganica Chimica Acta 398 (2013) 54–63
61
In 13C{1H} NMR spectra, the allenyl carbon appears as a triplet
complexes, trans-[ClPd(SR)(PMe3)2] (R = phenyl, 15; benzyl, 16),
are readily obtained (Scheme 4). In addition, complex 1 reacts with
0.5 equiv of benzene-1,4-dithiol to produce a dinuclear dithiolato-
(JPC = 3.7 Hz) at 195.5–200.5 ppm and this NMR pattern strongly
supports the existence of the
g
1-allenyl group in the products.
The ORTEP drawing of trans-[(SCN)Pd(CH@C@CH2)(PMe3)2] (11)
in Fig. 3 clearly shows a square plane consisting of Pd, NCS,
PMe3, and an allenyl group. In particular, the isolated complex 12
is believed to be a key intermediate in the Pd-catalyzed cyanation
of propargylic carbonates [23].
bridged complex, trans,trans-[Pd(PMe3)2Cl]2(l-SC6H4S) (17, 90%).
The IR stretching band (at 1910 cmꢁ1) of the allenyl group in the
starting material disappeared, because of the elimination of the
allenyl group. The molecular structure of 15 in Fig. 4 definitely
demonstrates the substitution of the allenyl group by the nuclo-
philic attack of the organic thiols and shows a square-planar
geometry.
When complex 1 is treated with 1 equiv of organic thiol such as
benzenethiol and benzylic thiol at room temperature, new thiolato
Fig. 4. ORTEP drawing of complex 15. Selected bond lengths (Å) and angles (°): Pd1–S1 2.2999(7), Pd1–P2 2.3096(7), Pd1–P1 2.3180(6), Pd1–Cl1 2.3449(7),S1–C1 1.763(3);
S1–Pd1–P2 88.38(3), S1–Pd1–P1 92.77(3), P2–Pd1–P1 178.47(3), S1–Pd1–Cl1 177.72(3), C1–S1–Pd1 104.46(8).
Fig. 5. ORTEP drawing of complex 19. The co-crystallized diethtyl ether molecule is omitted for clarity. Selected bond lengths (Å) and angles (°): Pd1–C1 2.052(2), Pd1–C28
2.072(2), Pd1–P1 2.2855(6), Pd1–Cl1 2.4110(6), C28–C29 1.429(3), C29–C30 1.204(3); C1–Pd1–C28 87.86(8), C1–Pd1–P1 173.12(6), C28–Pd1–P1 90.60(6), C28–Pd1–Cl1
174.91(6), C29–C28–Pd1 111.4(2), C30–C29–C28 177.3(3), C29–C30–C31 175.7(3).

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Y.-J. Kim et al. / Inorganica Chimica Acta 398 (2013) 54–63
3.3. Reactivity toward NHC (N-heterocyclic carbene) ligand
NHC (N-heterocyclic carbene) ligands are well known as one of
alternative complexes of tertiary phosphine ligands [24–27]. In
this work, we also examined the ligand replacement by the NHC
ligand. Complex 1 reacted with an equimolar amount of IPr (1,3-
bis(2,6-diisopropylphenyl)imidazol-2-ylidene) to give the ex-
pected the IPr–Pd(II) complex [ClPd(IPr)(CH@C@CH2)(PMe3)] (18,
88%) by the substitution of the PMe3 ligand. In contrast, the
reaction of complex 7 with IPr as shown in Scheme 4 causes
Scheme 6.
71% yield (Scheme 6). The IR spectrum of this complex displays a
the selective formation of the
g
1-propargyl Pd(II) complex
characteristic band at 1905 cmꢁ1 due to the
m
(@ꢂ@). This result
may provides an alternative method to prepare new
g
1-allenyl
[ClPd(IPr)(CH2C„CPh)(PMe3)] (19, 83%). IR absorption bands of
complexes 18 and 19 at 1916 (@ꢂ@) and 2184 (C„C) cmꢁ1 strongly
Pd(II) complexes.
g
1-allenyl or propargyl
In summary, we prepared g g
1-allenyl or 1-propargyl Pd(II) com-
plexes by the oxidative addition of organic propargyl halides to
[Pd(CH2@CHPh)(PR3)2] (PR3@PMe3, PEt3, PMe2Ph). In most cases,
formation of these complexes depended on the nature of the sup-
support the existence of a characteristic
group coordinated to the Pd atom. The 13C{1H} NMR peak at
200.1 ppm also indicates the carbon atom (@ꢂ@) in the
g
1-allenyl
group of complex 18. The ORTEP drawing of complex 19 clearly re-
veals a square plane consisting of IPr, Cl, PMe3, and a propargyl
group (Fig. 5). The propargyl ligand is located slightly perpendicu-
lar to the molecular plane, which may relieve steric congestion be-
tween the bulky IPr ligand and the alkynyl group. The 13C signal at
porting ligands and propargyl halides. Treatments of
g
1-allenyl
Pd(II) complex, trans-[(Cl)Pd(CH@C@CH2)(PR3)2] (PR3@PMe3,
PEt3) with excess Me3SiX (X = NCS, CN, N3) caused the ligand sub-
stitution to give trans-[(X)Pd(CH@C@CH2)(PR3)2]. Reactions of the
2
ꢁ9.7 ppm with a doublet (d JPC = 1.9 Hz) of the Pd–C28 carbon
g
1-allenyl Pd(II) complex with organic thiols gave new thiolato
also exhibits an upfield shift, indicating the effects of the strongly
complexes, trans-[ClPd(SR)(PMe3)2] (R = phenyl, benzyl), and a
new dinuclear dithiolato complex, trans,trans-[Pd(PMe3)2Cl]2(
SC6H4S) in high yields. In particular, the reaction of trans-
r
-donating IPr and electron-donating alkynyl ligands on the Pd to
l-
result in the shielding of that carbon atom.
Earlier works by Kurosawa and co-workers [7c,9,10a,b] demon-
[ClPd(C(Ph)@C@CH2)(PMe3)2] with 1 equiv of NHC (N-heterocyclic
strated the interconversion between
g g
1-allenyl Pd(II) and 1-prop-
carbene, IPr) afforded an
g
1-propargyl Pd(II) complex possessing
3-allenyl/propargyl intermediate.
the NHC ligand, [ClPd(IPr)(CH2C„CPh)(PMe3)], via an
g
3-allenyl/
argyl Pd(II) complexes via an
g
Our reactions also seem to follow somewhat a similar mechanistic
pathway. In a previous work, we reported the oxidative addition of
small molecules such as dichloromethane or 1,2-dichloroethylene
to the Pd(0) complex, [(Me3P)Pd(NHC)] (NHC = IPr) [28]. In this
work, we attempted to prepare complexes 18 and 19 by the similar
oxidative additions with organic propargyl chlorides. As shown in
Scheme 5, these reactions readily proceed to give corresponding
oxidative-addition products, [ClPd(IPr)(CH@C@CH2)(PMe3)] (18,
71% yield) and [ClPd(IPr)(CH2C„CPh)(PMe3)], (19, 66% yield),
which have been characterized by spectroscopy. Bulkier
3-chloro-1-phenyl-1-propyne oxidatively adds to the Pd(0) com-
propargyl intermediate.
Acknowledgment
This work was supported by Basic Science Research Program
through the National Research Foundation of Korea (NRF) funded
by the Ministry of Education, Science and Technology (Grant Nos.
2009-0074917 and 2012R1A1B3001569).
Appendix A. Supplementary material
plex to give the corresponding g
1-propargyl Pd(II) complex. These
CCDC 875234–875238 contain the supplementary crystallo-
graphic data for this paper. These data can be obtained free of
charge from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif. Supplementary data associ-
ated with this article can be found, in the online version, at http://
dx.doi.org/10.1016/j.ica.2012.12.011.
results suggest that the steric hindrance between the IPr group and
the substituent on the propargyl halide for the selective formation
of 18 and 19 plays a role in the reaction Pd(0) complex with prop-
argyl halides as well as in the reaction of 7 with IPr.
3.4. Oxidative addition of propargyl phenyl sulfide to the Pd(0)
complex
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