Palladium-assisted formation of carbon-carbon bonds. 5. Reactions of (o-styrylaryl)palladium complexes with alkynes. Synthesis of palladium complexes with highly functionalized indenyl ligands. Crystal and molecular structures of (1-benzyl-2,3-diphenyl-5,6,7-trimethoxyindenyl)- and (1-benzyl-3-phenyl-5,6,7-trimethoxyindenyl)palladium(II) complexes

Article abstract of DOI:10.1021/om950847h

The reactions of [Pd(E-R)Cl(tmeda)] [R = C6H(E-CH=CHPh)-6-(OMe)3-2,3,4; tmeda = N,N,N′,N′-tetramethylethylenediamine] with Tl(CF₃SO₃) and CH≡CH, PhC≡CPh, or PhC≡CH selectively give compounds [Pd(η-Ind)(tmeda)]CF₃SO₃ [Ind = 1-benzyl-5,6,7-trimethoxyindenyl (2), 1-benzyl-2,3-diphenyl-5,6,7-trimethoxyindenyl (3), 1-benzyl-3-phenyl-5,6,7-trimethoxyindenyl (4)]. When a mixture of [Pd(E-R)Cl(bipy)] (bipy = 2,2′-bipyridine) and [Pd(Z-R)Cl(bipy)] is reacted with Tl(CF₃SO₃) and MeC≡CMe, the complex [Pd(η-Ind)(bipy)]CF₃SO₃ [1-benzyl-2,3-dimethyl-5,6,7-trimethoxyindenyl (5)] is obtained. The structures of 3 and 4 have been determined by X-ray studies at 203 and 173 K, respectively. According to the structural data for 3 and 4, the hapticity of the indenyl ligands is intermediate between η³-and η⁵-coordination.

Full text of DOI:10.1021/om950847h

1422
Organometallics 1996, 15, 1422-1426
P a lla d iu m -Assisted F or m a tion of Ca r bon -Ca r bon Bon d s.
5.1 Rea ction s of (o-Styr yla r yl)p a lla d iu m Com p lexes w ith
Alk yn es. Syn th esis of P a lla d iu m Com p lexes w ith High ly
F u n ction a lized In d en yl Liga n d s. Cr ysta l a n d Molecu la r
Str u ctu r es of
(1-Ben zyl-2,3-d ip h en yl-5,6,7-tr im eth oxyin d en yl)- a n d
(1-Ben zyl-3-p h en yl-5,6,7-tr im eth oxyin d en yl)p a lla d iu m (II)
Com p lexes
J ose´ Vicente,*,† J ose´-Antonio Abad,*,‡ and Ralph Bergs
Grupo de Quı´mica Organometa´lica, Departamento de Quı´mica Inorga´nica, Facultad de
Quı´mica, Universidad de Murcia, Aptdo. 4021, E-30071 Murcia, Spain
Peter G. J ones*,§ and M. Carmen Ram´ırez de Arellano
Institut fu¨r Anorganische und Analytische Chemie, Technische Universita¨t Braunschweig,
Postfach 3329, 38023 Braunschweig, Germany
Received October 25, 1995X
The reactions of [Pd(E-R)Cl(tmeda)] [R ) C6H(E-CHdCHPh)-6-(OMe)3-2,3,4; tmeda )
N,N,N′,N′-tetramethylethylenediamine] with Tl(CF3SO3) and CHtCH, PhCtCPh, or PhCtCH
selectively give compounds [Pd(η-Ind)(tmeda)]CF3SO3 [Ind ) 1-benzyl-5,6,7-trimethoxyin-
denyl (2), 1-benzyl-2,3-diphenyl-5,6,7-trimethoxyindenyl (3), 1-benzyl-3-phenyl-5,6,7-tri-
methoxyindenyl (4)]. When a mixture of [Pd(E-R)Cl(bipy)] (bipy ) 2,2′-bipyridine) and [Pd(Z-
R)Cl(bipy)] is reacted with Tl(CF3SO3) and MeCtCMe, the complex [Pd(η-Ind)(bipy)]CF3SO3
[1-benzyl-2,3-dimethyl-5,6,7-trimethoxyindenyl (5)] is obtained. The structures of 3 and 4
have been determined by X-ray studies at 203 and 173 K, respectively. According to the
structural data for 3 and 4, the hapticity of the indenyl ligands is intermediate between η3-
and η5-coordination.
In tr od u ction
best of our knowledge, [Pd2(µ-η3-C9H7)2(CNR)2] (R ) But,
C6H3Me2-2,6, C6H2Me3-2,4,6, and C6H2But -2,4,6)17 and
3
It is well-known that transition metal indenyl com-
plexes display a higher reactivity in stoichiometric and
catalytic reactions than their cyclopentadienyl ana-
logues.2-4 Very interesting polymerization catalysts
have been described that involve ansa metallocenes
containing indenyl groups.5 In addition, some rhodium,
iridium, and early transition metal catalysts with
substituted indenyl ligands show increased activity and
lifetimes compared with the corresponding unsubsti-
tuted derivatives.6-8 However, apart from the parent
ligand C9H7, very few substituted indenyl complexes are
known, most of them being alkyl-, aryl-,2,5-13 halo-,14,15
or ferrocenylindenyl derivatives.16 Furthermore, to the
[Pd2(η3-C9H7)2(µ-Cl)2]18 are the only known indenylpal-
ladium complexes. Several impure (methyl- or (phe-
nylindenyl)palladium derivatives, prepared from the
reaction of cyclopropenes and [PdCl2(PhCN)2], have been
reported only in a preliminary communication.19
The reactivity of arylpalladium compounds with
alkynes constitutes a topic of current interest.20 These
reactions usually involve insertion of 1, 2, or 3 alkyne
molecules into the carbon-palladium bond giving new
species, which may be stable and isolable or can undergo
(9) Kakkar, A. K.; J ones, S. F.; Taylor, N. J .; Collins, S.; Marder, T.
B. J . Chem. Soc., Chem. Commun. 1989, 1454.
(10) Lewis, J .; Raithby, P. R.; Ward, G. N. J . Chem. Soc., Chem.
Commun. 1995, 755.
(11) O’Hare, D.; Murphy, V.; Diamond, G. M.; Arnold, P.; Mountford,
P. Organometallics 1994, 13, 4689 and references therein.
(12) Ceccon, A.; Elsevier, C. J .; Ernsting, J . M.; Gambaro, A.; Santi,
S.; Venzo, A. Inorg. Chim. Acta 1993, 204, 15.
(13) Erker, G.; Aulbach, M.; Knickmeier, M.; Wingbermuhle, D.;
Kruger, C.; Nolte, M.; Werner S. J . Am. Chem. Soc. 1993, 115, 4590.
(14) Honan, M. B.; Atwood, J . L.; Bernal, I.; Herrmann, W. A. J .
Organomet. Chem. 1979, 179, 403.
(15) Han, Y. H; Heeg, M. J .; Winter, C. H. Organometallics 1994,
13, 3009.
(16) Scott, P.; Rief, U.; Diebold, J .; Brintzinger, H. H. Organome-
tallics 1993, 12, 3094.
(17) Tanase, T.; Nomura, T.; Fukushima, T.; Yamamoto, Y.; Koba-
yashi, K. Inorg. Chem. 1993, 32, 4578.
(18) Nakasuji, K.; Yamaguchi, M.; Murata, I.; Tatsumi, K.; Naka-
mura, A. Organometallics 1984, 3, 1257. Samuel, E.; Bigorgne, M. J .
Organomet. Chem. 1969, 19, 9.
† E-mail: jvs@fcu.um.es.
‡ E-mail: jaab@fcu.um.es.
§ E-mail: P.J ONES@TU-BS.DE.
X Abstract published in Advance ACS Abstracts, February 1, 1996.
(1) Part 4: Vicente, J .; Abad, J . A.; Ferna´ndez-de-Bobadilla, R.;
J ones, P. G.; Ram´ırez de Arellano, M. C. Organometallics 1996, 15,
24.
(2) Frankom, T. M.; Green, J . C.; Nagy, A.; Kakkar, A. K.; Marder,
T. B. Organometallics 1993, 12, 3688 and references therein.
(3) Trost, B. M.; Kulawiec, R. J . J . Am. Chem. Soc. 1993, 115, 2027.
(4) O’Connor, J . M.; Casey, C. P. Chem. Rev. 1987, 87, 307.
(5) Halterman, R. L. Chem. Rev. 1992, 92, 965. Razavi, A.; Atwood,
J . L. J . Am. Chem. Soc. 1993, 115, 7529 and references therein.
(6) Hauptman, E.; Saboetienne, S.; White, P. S.; Brookhart, M.;
Garner, J . M.; Fagan, P. J .; Calabrese, J . C. J . Am. Chem. Soc. 1994,
116, 8038.
(7) Bonifaci, C.; Ceccon, A.; Gambaro, A.; Ganis, P.; Mantovani, L.;
Santi, S. J . Organomet. Chem. 1994, 475, 267.
(8) De Boer, H. J . R.; Royan, B. W. J . Mol. Catal. 1994, 90, 171 and
references therein.
(19) Fiato, R. A.; Mushak, P.; Battiste, M. A. J . Chem. Soc., Chem.
Commun. 1989, 869.
(20) Pfeffer, M. Recl. Trav. Chim. Pays-Bas 1990, 109, 567.
0276-7333/96/2315-1422$12.00/0 © 1996 American Chemical Society

Pd-Assisted Formation of C-C Bonds
Organometallics, Vol. 15, No. 5, 1996 1423
described elsewhere.21 Some 13C NMR signals were assigned
with the help of the DEPT technique. The carbon analyses
for complexes 2-4 give low values (-2 to -3% absolute error)
despite repeated recrystallizations. However, good analyses
for H, N, and S as well as their NMR spectra prove they are
pure compounds. We believe this problem is associated with
the presence of triflate in these compounds. Complexes 1a ,b
were prepared as previously described.22
Rea ction of 1a w ith HCtCH. Syn th esis of 2. Acetylene
was bubbled for 5 min through a suspension of 1a (120 mg,
0.228 mmol) and Tl(CF3SO3) (81 mg, 0.228 mmol) in CH2Cl2
(10 cm3). The brown suspension was stirred for 20 h and
filtered over anhydrous MgSO4. The solution was concentrated
to 1 cm3, and diethyl ether was added to precipitate 2 as a
brown solid. Yield: 88 mg, 58%. Mp: 145-147 °C. ΛM
(acetone): 104 Ω-1 cm2 mol-1
.
NMR: 1H-NMR (200 MHz,
CDCl3, ppm) 7.20-7.40 (m, C6H5, 5 H), 6.71 (d, indenyl-CH, 1
3
H, J ) 3 Hz), 6.44 (s, Aryl-H, 1 H), 5.71 (d, indenyl-CH, 1 H,
3J ) 3 Hz), 3.92, 3.81 and 3.79 (s, MeO, 3 H), 3.36 (d, CH2Ph,
1 H, 2J ) 15 Hz), 3.27 (d, CH2Ph, 1 H, 2J ) 15 Hz), 2.55-2.85
(m, CH2CH2, 4 H), 2.87, 2.77, 2.75, and 2.60 (s, MeN, 3 H);
13C NMR (50 MHz, CDCl3, ppm) 154.34, 144.79, 141.29, 136.14,
and 133.57 (C-aryl), 128.79 and 128.23 (o,m-C6H5), 126.97 (p-
C6H5), 122.32 (C-aryl), 109.66 (indenyl-CH), 96.57 (R-CH),
93.74 (indenyl-C), 74.48 (indenyl-CH), 61.73 (CH2CH2), 61.17
and 61.10 (MeO), 60.73 (CH2CH2), 56.52 (MeO), 54.32, 52.73,
51.61, and 51.39 (MeN), 32.80 (PhCH2). Anal. Calcd for
F igu r e 1. Crystal structure of 3. Selected bond distances
(Å) and angles (deg) not included in the text: Pd-N(1)
2.147(4), Pd-N(2) 2.145(4), C(1)-C(2) 1.434(6), C(1)-C(12)
1.491(5), C(2)-C(3) 1.422(6), C(3)-C(11) 1.479(6), C(11)-
C(12) 1.424(6), C(12)-C(13) 1.392(6), C(13)-C(14) 1.395-
(6), C(14)-C(15) 1.396(6), C(15)-C(16) 1.382(6), N(2)-Pd-
N(1) 84.3(2), C(2)-C(1)-C(12) 107.5(4), C(3)-C(2)-C(1)
108.1(4), C(2)-C(3)-C(11) 107.8(4), C(12)-C(11)-C(3) 107.7-
(4), C(11)-C(12)-C(1) 107.0(4).
C
26H35F3N2O6PdS: C, 46.82; H, 5.29; N, 4.20; S, 4.81. Found:
C, 45.44; H, 5.51; N, 4.58; S, 4.96.
Rea ction of 1a w ith P h CtCP h . Syn th esis of 3. Brown
3 was similarly prepared from diphenylacetylene (68 mg, 0.380
mmol), 1a (100 mg, 0.190 mmol), and Tl(CF3SO3) (67 mg, 0.190
mmol). Yield: 106 mg, 56%. Mp: 158-159 °C. ΛM (ac-
etone): 109 Ω-1 cm2 mol-1. NMR: 1H-NMR (200 MHz, CDCl3,
ppm) 7.25-7.35 (m, C6H5, 6 H), 7.05-7.20 (m, C6H5, 7 H),
6.85-6.93 (m, C6H5, 2 H), 6.57 (s, R-H, 1 H), 3.91, 3.85, and
3.82 (s, MeO, 3 H), 3.31 (s, CH2Ph, 2 H), 2.60-3.00 (m, CH2-
CH2, 4 H), 3.01, 2.73, 2.63, and 2.40 (s, MeN, 3 H); 13C NMR
(50 MHz, CDCl3, ppm) 154.49, 145.91, 142.23, 134.91, 132.91,
131.58, and 131.56 (C-aryl), 131.04 (CH), 129.84 (C-aryl),
128.61, 128.40, 128.37, 128.25, 128.06, 127.13, 126.68 (CH-
aryl), 118.90, 96.88, and 94.95 (indenyl-C), 90.86 (CH-aryl),
62.14 and 61.38 (CH2CH2), 60.82, 60.22, and 56.54 (MeO),
53.07, 52.75, 50.72, and 50.40 (MeN), 30.91 (PhCH2). Anal.
Calcd for C38H43F3N2O6PdS: C, 55.71; H, 5.29; N, 3.42; S, 3.91.
Found: C, 54.50; H, 5.41; N, 3.60; S, 3.83. Single crystals of
3 were obtained by liquid diffusion of diethyl ether into a
solution of 3 in dichloromethane.
X-r a y Str u ctu r e Deter m in a tion of 3.2CH2Cl2. Crystal
data: C40H47Cl4F3N2O6PdS, monoclinic, P21/c, a ) 18.301(2)
Å, b ) 11.335(2) Å, c ) 21.351(3) Å, â ) 96.380(8)°, V ) 4401.5
Å3, Z ) 4, Dx ) 1.493 Mg m-3, λ(Mo KR) ) 0.710 73 Å, µ ) 0.8
mm-1. Data collection: A dichroic brown/violet plate 0.75 ×
0.4 × 0.1 mm was mounted on a Siemens P4 diffractometer
fitted with an LT-2 low-temperature device. A total of 10 228
intensities were recorded at 203 K to 2θmax 50°. After
absorption corrections (ψ-scans), 7743 unique reflections were
used for all calculations. Structure refinement was on F2
(program SHELXL-93, G. M. Sheldrick, Univ. of Go¨ttingen)
with riding H atoms; the carbon atoms of the tmeda ligand
are disordered over two sites wR(F2) ) 0.098, and conventional
R(F) ) 0.047 for 502 parameters and 510 restraints (S ) 0.81;
maximum ∆F ) 0.66 e Å-3).
F igu r e 2. Crystal structure of 4. Selected bond distances
(Å) and angles (deg) not included in the text: Pd-N(1)
2.126(5), Pd-N(2) 2.132(5), C(1)-C(2) 1.415(7), C(1)-C(12)
1.500(6), C(2)-C(3) 1.407(7), C(3)-C(11) 1.482(6), C(11)-
C(12) 1.407(6), C(12)-C(13) 1.409(6), C(13)-C(14) 1.398-
(7), C(14)-O(2) 1.375(5), C(14)-C(15) 1.396(7), C(15)-
C(16) 1.386(6); N(1)-Pd-N(2) 84.1(2), C(2)-C(1)-C(12)
105.8(4), C(3)-C(2)-C(1) 110.3(4), C(2)-C(3)-C(11) 106.3-
(4), C(12)-C(11)-C(3) 108.1(4), C(11)-C(12)-C(1) 107.4-
(4).
a depalladation process to give organic compounds.20,21
The subject of this article is the reactivity of some (o-
styrylaryl)palladium complexes with alkynes, leading
to indenyl complexes.
Rea ction of 1a w ith P h CtCH. Syn th esis of 4. Dark
brown 4 was similarly prepared from phenylacetylene (44 mg,
0.431 mmol), 1a (100 mg, 0.190 mmol), and Tl(CF3SO3) (67
mg, 0.190 mmol). Yield: 117 mg, 83%. Mp: 96-98 °C. ΛM
Exp er im en ta l Section
1
Infrared spectra, H and 13C NMR spectra, C, H, N, and S
(acetone): 115 Ω-1 cm2 mol-1
.
NMR: 1H-NMR (200 MHz,
analyses, conductance measurements, melting point determi-
nations, and purification of solvents were carried out as
CDCl3, ppm) 7.85-7.95 (m, C6H5, 2 H), 7.20-7.50 (m, C6H5, 8
(21) Vicente, J .; Abad, J . A.; Gil-Rubio, J .; J ones, P. G. Organome-
tallics 1995, 14, 2677.
(22) Vicente, J .; Abad, J . A.; Bergs, R.; J ones, P. G.; Bautista, D. J .
Chem. Soc., Dalton Trans. 1995, 3093.

1424 Organometallics, Vol. 15, No. 5, 1996
Vicente et al.
Sch em e 1. Su ggested P a th w a y (Da sh ed Ar r ow s) for th e Syn th esis of 2-5 (LL ) tm ed a , LL′ ) bip y)
Ta ble 1. Cr ysta l Da ta a n d Str u ctu r e Refin em en t for 3 a n d 4
empirical formula
fw
C40H47Cl4F3N2O6PdS
989.06
C33H40Cl3F3N2O6PdS
862.48
temp, K
wavelength, Å
cryst system
space group
a, Å
203
0.710 73
monoclinic
P21/c
173
0.710 73
monoclinic
P21/c
18.301(2)
14.836(2)
b, Å
11.335(2)
12.150(2)
c, Å
21.351(3)
20.906(3)
â, deg
96.380(8)
4401.5(11)
1.493
0.771
101.58(1)
3691.7(10)
1.552
0.836
V, Å3
D
calc, Mg/m3
abs coef, mm-1
F(000)
2024
1760
cryst size, mm
θ, deg
lim ind
0.75 × 0.40 × 0.10
0.80 × 0.30 × 0.20
3.11-25.00
3.09-25.00
-21 e h e 5, 0 e k e 13, -25 e l e 25
10 228
-17 e h e 1, -14 e k e 3, -24 e l e 24
8618
reflcns collcd
indepdt reflcns
abs corr
7743 [R(int) ) 0.0394]
ψ-scans
6462 [R(int) ) 0.0285]
ψ-scans
max and min transm
refinement method
data/restraints/parameters
goodness-of-fit on F2
final R indices [I > 2σ(I)]
R indices (all data)
largest diff peak and hole, e‚Å-3
0.781 and 0.740
full-matrix least squares on F2
7741/510/502
0.869 and 0.735
full-matrix least squares on F2
6461/469/463
0.807
0.894
R1 ) 0.0469, wR2 ) 0.0855
R1 ) 0.1072, wR2 ) 0.0979
0.665, -0.529
R1 ) 0.0471, wR2 ) 0.0981
R1 ) 0.1010, wR2 ) 0.1132
0.468, -0.687
H), 6.75 and 6.56 (s, aryl-H and indenyl-CH, 1 H), 3.86, 3.84,
and 3.82 (s, MeO, 3 H), 3.41 (d, CH2Ph, 1 H, 2J ) 15 Hz), 3.26
(d, CH2Ph, 1 H, 2J ) 15 Hz), 2.65-2.90 (m, CH2-CH2, 4 H),
2.78, 2.67, 2.43, and 2.31 (s, MeN, 3 H); 13C NMR (50 MHz,
CDCl3, ppm) 154.48, 146.09, 142.18, 135.93, 135.09, 133.15 (C-
aryl), 128.86, 128.76, 128.53, 128.37, 127.05 (CH-aryl), 120.22
(C-aryl), 110.33 (indenyl-C), 96.65 (R-CH), 95.06, 91.63 (inde-
nyl-C), 61.64 and 61.21 (CH2CH2), 60.96, 60.75, and 56.53
(MeO), 51.87, 51.46, 51.32, and 50.16 (MeN), 32.83 (PhCH2).
Anal. Calcd for C32H39F3N2O6PdS: C, 51.72; H, 5.29; N, 3.77;
S, 4.31. Found: C, 50.72; H, 5.41; N, 3.90; S, 4.28. Single
crystals of 4 were obtained by liquid diffusion of diethyl ether
into a solution of 4 in chloroform.
122-124 °C. ΛM (acetone): 110 Ω-1 cm2 mol-1 NMR: 1H-
.
NMR (200 MHz, CDCl3, ppm) 8.65-8.72, 8.40-8.50, 8.05-
8.25, 7.80-7.90, 7.60-7.70 (m, 8 H, bipy), 7.15-7.45 (m, C6H5,
2
5 H), 6.62 (s, aryl-H, 1 H), 4.06 (d, CH2Ph, 1 H, J ) 15 Hz),
2
3.88, 3.79, and 3.74 (s, MeO, 3 H), 3.47 (d, CH2Ph, 1 H, J )
15 Hz), 2.34, 1.82 (s, indenyl-CH3, 3 H); 13C NMR (50 MHz,
CDCl3, ppm) 154.51 and 153.11 (C-aryl), 153.00 (CH-aryl),
152.33 (C-aryl), 151.14 (CH-aryl), 145.62 and 141.71 (C-aryl),
140.87 and 140.61 (CH-aryl), 135.13 and 133.28 (C-aryl),
128.72, 128.29, 127.95, 126.97, and 126.80 (CH-aryl), 124.31
(indenyl-C), 124.15 and 123.90 (CH-aryl), 121.69 (C-aryl), 97.21
(R-CH), 91.18 and 90.86 (indenyl-C), 60.90, 60.77 and 56.40
(MeO), 30.70 (PhCH2), 12.50 and 12.38 (indenyl-CH3). Anal.
X-r a y St r u ct u r e Det er m in a t ion of 4‚CH Cl3: Crystal
data: C33H40Cl3F3N2O6PdS, monoclinic, P21/c, a ) 14.836(2)
Å, b ) 12.150(2) Å, c ) 20.906(3) Å, â ) 101.58(1)°, V ) 3691.7
Å3, Z ) 4, Dx ) 1.552 Mg m-3, µ ) 0.8 mm-1. Other details
are as for 3, with the following differences: dark red prism
0.8 × 0.3 × 0.2 mm, 8618 intensities at 173 K, 6462 unique,
wR(F2) ) 0.113, conventional R(F) ) 0.047 for 463 parameters
and 469 restraints (S ) 0.89; maximum ∆F ) 0.47 e Å-3).
Rea ction of 1b (Z/E Mixtu r e) w ith MeCtCMe. Syn -
th esis of 5. Red brown 5 was similarly prepared from
2-butyne (40 mg, 0.740 mmol), 1b (120 mg, 0.211 mmol), and
Tl(CF3SO3) (75 mg, 0.211 mmol). Yield: 125 mg, 81%. Mp:
Calcd for
Found: C, 52.23; H, 4.47; N, 3.91.
C32H31F3N2O6PdS: C, 52.29; H, 4.25; N, 3.81.
Resu lts a n d Discu ssion
The complex [Pd(R)Cl(LL)] (1a ) [R ) C6H(E-CHd
CHPh)-6-(OMe)3-2,3,4; LL ) tmeda ) N,N,N′,N′-tet-
ramethylethylenediamine; see Scheme 1], which we
have prepared through a Wittig reaction,22 reacts with
HCtCH or PhCtCPh, in the presence of Tl(CF3SO3),
to give the indenylpalladium derivative 2 or 3, respec-

Pd-Assisted Formation of C-C Bonds
Organometallics, Vol. 15, No. 5, 1996 1425
Ta ble 2. Atom ic Coor d in a tes (×104) a n d
Equ iva len t Isotr op ic Disp la cem en t P a r a m eter s
(Å2 × 103) for 3a
tively. As far as we are aware, these are the first
examples in which an indenyl ligand is formed through
such a simple procedure. Also remarkable is the highly
functionalized nature of the indenyl ligands. If the
reaction is carried out with an unsymmetric alkyne,
such as PhCtCH, the reaction is regioselective and
complex 4, with the phenyl group in the 3 position, is
formed as the only isomer. The clean results achieved
with terminal alkynes, even with acetylene, in particu-
lar contrasts markedly with the usual reactions of
arylpalladium complexes with terminal alkynes to give
intractable mixtures.20,23 The reactions with the other
alkynes are also very clean as observed in the NMR of
the crude products.
A reasonable pathway for the formation of these
indenylpalladium complexes is proposed in Scheme 1.
The synthesis of monoinserted palladium compounds,
such as A, when arylpalladium complexes are reacted
with alkynes, is well documented.20 Addition of the
Pd-C bond to the alkenyl sustituent, which is a well-
known process occurring in palladium-catalyzed cycliza-
tion reactions,24 would give B. The successive â-hydride
elimination and readdition to give a σ-indenyl complex
E could occur through hydrido(η2-benzofulvene)palla-
dium(II) complexes C and D. Finally, the three-
coordinated complex E would give the more stable
η-indenyl complex.
According to this proposal, the regioselectivity of the
reaction with PhCtCH must be determined in the first
step. However, when this type of insertion reaction is
regiospecific and the alkyne does not contain electron-
withdrawing substituents, the regioisomer obtained is
that in which the least bulky substituent is adjacent to
the aryl ligand.21,23,25,26 The same applies to reactions
of alkynes with arylmanganese(II) complexes27 or with
haloarenes in the presence of catalytic amounts of
palladium complexes.28 Therefore, the insertion of
PhCtCH follows a contrasting pattern. As far as we
are aware, there is only one other reported exception.26
Further, according to our pathway the result would be
the same if the Z-isomer of the starting complex were
used. In fact, by reaction of a mixture of [Pd(E-R)Cl-
(bipy)] (bipy ) 2,2′-bipyridine) and [Pd(Z-R)Cl(bipy)]
(1b) with Tl(CF3SO3) and MeCtCMe, only one complex,
[Pd(η-Ind)(bipy)]CF3SO3 [1-benzyl-2,3-dimethyl-5,6,7-
trimethoxy-indenyl (5)], is obtained.
Complexes 3 and 4 have been studied by X-ray
diffraction, confirming the proposed structures (see
Figures 1 and 2 and Tables 1-3; figure captions give
selected bond lengths and angles). In both cases, the
distances of Pd to the allylic carbons C(1) [2.253(4),
2.208(5) Å; here and below, data are for 3 and 4,
respectively], C(2) [2.187(5), 2.151(5) Å], and C(3) [2.191-
(4), 2.212(6) Å] are significantly shorter than those to
C(11) [2.585(5), 2.572(5) Å] and C(12) [2.564(4) Å, 2.564-
x
y
z
U(eq)
Pd
O(1)
O(2)
O(3)
C(1)
C(2)
C(3)
C(4)
N(1)
N(2)
C(5)
C(6)
C(7)
C(8)
C(9)
C(10)
C(5′)
C(6′)
C(7′)
C(8′)
C(9′)
C(10′)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(17)
C(18)
C(19)
C(21)
C(22)
C(23)
C(24)
C(25)
C(26)
C(31)
C(32)
C(33)
C(34)
C(35)
C(36)
C(41)
C(42)
C(43)
C(44)
C(45)
C(46)
S
2547.9(2)
819(2)
6352.4(3)
8004(3)
7298(3)
5329(3)
6293(4)
5255(4)
4644(4)
3464(4)
6065(4)
8150(4)
5585(8)
5221(8)
7205(7)
8196(7)
9010(8)
8427(8)
6173(16)
4970(12)
7096(12)
8159(12)
8815(15)
8842(14)
5140(4)
6178(4)
6918(4)
6589(4)
5546(4)
4821(4)
8394(4)
8139(5)
4416(5)
7106(4)
7573(4)
8320(4)
8609(5)
8117(4)
7368(4)
4861(4)
4542(4)
4066(4)
3908(4)
4229(4)
4714(4)
2436(4)
1861(4)
928(4)
3458.2(2)
2365.5(13)
1140.3(14)
930.9(14)
3446(2)
3733(2)
3269(2)
3356(2)
3271(2)
3603(2)
2626(4)
3713(4)
3338(5)
3320(4)
3329(5)
4301(3)
2581(5)
3503(7)
3591(8)
3608(9)
3006(7)
4113(7)
2646(2)
2751(2)
2245(2)
1644(2)
1550(2)
2048(2)
1980(2)
1018(3)
807(2)
3760(2)
4354(2)
4643(2)
4349(2)
3763(2)
3479(2)
4397(2)
4597(2)
5192(2)
5587(2)
5395(2)
4804(2)
3323(2)
2760(2)
2729(3)
3265(3)
3828(3)
3861(2)
3040.4(7)
2976(2)
3089(2)
3457(2)
2276(3)
2238(2)
2162(2)
1819.9(15)
1068(4)
1025.0(13)
379.2(9)
353(4)
26.8(1)
29.1(8)
1043(2)
1745(2)
1316(2)
1654(3)
2007(2)
2383(2)
3663(2)
2893(2)
3688(6)
4057(6)
4026(5)
3601(5)
2364(5)
3043(5)
3653(10)
4034(11)
4067(8)
3689(7)
2536(9)
2650(9)
1732(2)
1325(2)
1103(2)
1256(3)
1634(3)
1887(3)
159(3)
44.1(10)
42.3(10)
23.6(10)
24.4(11)
22.9(11)
26.5(11)
41.5(12)
43.6(12)
54.2(12)
54.2(12)
54(2)
54(2)
54.2(12)
54.2(12)
54.2(12)
54.2(12)
54(2)
54(2)
54.2(12)
54.2(12)
21.8(10)
21.9(10)
23.5(10)
29.0(12)
30.2(12)
28.6(11)
39.6(14)
77(2)
1584(4)
2235(3)
842(3)
1058(3)
600(3)
48(2)
24.0(10)
29.9(12)
39.0(14)
40.8(12)
34.6(12)
27.1(11)
23.8(10)
31.4(12)
40.2(13)
43.0(14)
42.5(14)
33.5(12)
27.0(11)
33.1(12)
42.0(14)
48.7(15)
46.6(14)
37.5(14)
66.1(5)
98(2)
90(2)
79.7(13)
59(2)
106(2)
84.2(13)
78.2(12)
124(3)
170.0(13)
112.3(8)
172(5)
-82(3)
-319(3)
143(3)
1632(3)
960(3)
942(3)
1580(3)
2236(3)
2274(3)
1852(3)
1637(3)
1146(3)
855(3)
1060(3)
1563(3)
6422.8(9)
6852(3)
6826(3)
5861(2)
5894(4)
5470(2)
5469(2)
6332(2)
3973(5)
3705(2)
4282.1(13)
4223(6)
4478(2)
3636(2)
564(4)
1126(4)
2047(4)
6432(2)
5339(5)
7509(4)
6346(5)
6510(6)
7468(4)
5589(3)
6566(3)
8563(7)
7161(2)
9108(2)
3031(8)
4293(3)
3058(2)
O(4)
O(5)
O(6)
C(99)
F(1)
F(2)
F(3)
C(97)
Cl(1)
Cl(2)
C(98)
Cl(3)
Cl(4)
701(2)
-285.3(11)
172.2(13)
137.2(10)
a
U(eq) is defined as one-third of the trace of the orthogonalized
(23) Maassarani, F.; Pfeffer, M.; Spencer, J .; Wehman, E. J . Orga-
nomet. Chem. 1994, 466, 265.
Uij tensor.
(24) See for example: Ma, S. M.; Negishi, E. I. J . Am. Chem. Soc.
1995, 117, 6345 and references therein.
(25) Maassarani, F.; Pfeffer. M; Le Borgne, G. Organometallics 1987,
6, 2043.
(26) Spencer, J .; Pfeffer, M.; Kyritsakas, N.; Fischer, J . Organome-
tallics 1995, 14, 2214.
(27) Liebenskind, L. S.; Gasdaska, J . R.; McCallum, J . S.; Tremont,
S. J . J . Org. Chem. 1989, 54, 669.
(28) Larock, R. C.; Doty, M. J ., Cacchi, S. J . Org. Chem. 1993, 58,
4579. Larock, R. C.; Yum, E. K.; Doty, M. J .; Sham, K. K. C. J . Org.
Chem. 1995, 60, 3270.
(4) Å]. However, these differences are not sufficient to
allow the coordination to be described as simply η3.
Thus, the ∆MC values (difference between the average
of the metal carbon distances to the “allyl” and “ene”
carbons)14,29 0.35 and 0.39 Å lie between those expected
for an η3 (0.5-0.9 Å) and those expected for an η5-

1426 Organometallics, Vol. 15, No. 5, 1996
Vicente et al.
Ta ble 3. Atom ic Coor d in a tes (×104) a n d
Equ iva len t Isotr op ic Disp la cem en t P a r a m eter s
(Å2 × 103) for 4a
vector)14,29,30c (12.7, 12.4°), which lie between the cor-
responding values observed in η3- (or η3-C5H5) (20-24°)
and η5-complexes (2-5°).29,30c However, whereas the
fold angles (dihedral angles between the plane defined
by the three allylic carbons and that formed by the
benzenoid carbons)9 (7, 10°) are in the range corre-
sponding to η5-complexes (7.4-10°; the η3-complexes
show values of 20-26°),30c the slip distortions, ∆ (dis-
tance between the C5 ring centroid and the projection
of the metal atom on the ring)14,29,30c (0.44, 0.39 Å), are
near to the lowest limit of 0.3 Å proposed for an
η3-coordination.29 In addition, C-C bond distances
within the allylic and benzenoid fragments (C(1-3),
C(11)/(12), respectively) are significantly shorter than
the bonds between them (see figure captions), which
supports an η3-coordination. In consequence, we cannot
assign unambigously the hapticity of the substituted
indenyl ligands in our complexes.
x
y
z
U(eq)
Pd
O(1)
O(3)
N(1)
N(2)
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
C(9)
C(10)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(17)
O(2)
C(18)
C(18′)
C(19)
C(21)
C(22)
C(23)
C(24)
C(25)
C(26)
C(31)
C(32)
C(33)
C(34)
C(35)
C(36)
C(99)
S
3438.3(3)
1190(2)
2622(3)
4878(3)
3689(3)
1930(3)
2383(4)
2899(3)
3414(3)
5349(4)
5043(4)
5255(5)
4639(4)
3040(4)
3626(5)
2569(3)
1990(3)
1708(3)
1937(3)
2471(3)
2821(3)
1360(5)
1613(2)
2440(7)
548(7)
3091(4)
1290(4)
1484(5)
842(6)
15(6)
-177(5)
452(4)
2764(4)
2627(5)
2013(6)
1505(6)
1637(6)
2243(4)
3841(4)
4601.6(15)
4368(5)
4454(4)
5492(3)
4005(4)
2986(3)
3886(3)
207(5)
3695.0(4)
3410(3)
6732(3)
3884(5)
2033(4)
3856(5)
4498(5)
5338(5)
6242(5)
4514(6)
4443(6)
2756(6)
2020(6)
1630(5)
1283(6)
5411(4)
4504(4)
4313(4)
5090(4)
6011(4)
6160(4)
2761(6)
4952(3)
4588(10)
5275(10)
7731(5)
2978(5)
2368(5)
1596(5)
1432(6)
2038(7)
2800(6)
7124(5)
8097(5)
8867(6)
8664(6)
7716(6)
6950(5)
965(6)
3142.2(2)
4114(2)
5005(2)
3487(2)
3455(2)
2846(2)
2442(2)
2807(2)
2551(2)
3042(3)
4129(3)
3551(3)
3850(3)
3854(3)
2880(3)
3429(2)
3464(2)
4059(2)
4559(2)
4491(2)
3930(2)
4681(3)
5126(2)
5715(5)
4945(5)
4915(3)
2563(2)
2042(3)
1718(3)
1912(4)
2425(3)
2743(3)
2228(2)
2539(3)
2241(3)
1612(3)
1302(3)
1598(3)
5814(3)
6023.4(8)
6577(3)
5447(2)
6157(3)
5307(2)
5672(3)
6299(2)
3888(4)
4264(2)
4477(5)
3589(4)
3770(3)
3887(4)
4544(4)
41.4(2)
45.6(10)
50.6(10)
54.5(14)
53.3(13)
38.8(12)
42.1(14)
37.2(12)
45.4(13)
75(2)
64(2)
76(2)
67(2)
67(2)
76(2)
31.6(11)
30.5(11)
32.2(11)
37.4(12)
36.6(13)
33.6(12)
72(2)
54.0(11)
49(2)
49(2)
54(2)
50.3(15)
60(2)
79(2)
98(3)
87(2)
67(2)
44.6(13)
62(2)
86(2)
95(3)
79(2)
60(2)
64(2)
As expected, the methylene protons of the benzyl
substituent appear as an AB system in the 1H NMR
spectra of all complexes except for 3, which shows a
deceptively simple singlet.
Con clu sion s
By reaction of (o-styrylaryl)palladium complexes with
Tl(CF3SO3) and different alkynes, highly functionalized
indenyl palladium complexes are obtained. The process
requires a monoinsertion of the alkyne into the C-Pd
bond and a H scrambling involving a C-H bond cleav-
age and a C-H bond formation. The hapticity of the
indenyl ligands is intermediate between η3- and η5-
coordination. The reactions are highly specific. The
regioselectivity observed with PhCtCH is contrary to
the usually found in other processes involving the
monoinsertion of an alkyne into a Pd-aryl bond.
Ack n ow led gm en t. We thank the Direccio´n General
de Investigacio´n Cient´ıfica y Te´cnica (Grant PB92-0982-
C) and the Fonds der Chemischen Industrie for financial
support. R.B. is grateful to the Human Capital and
Mobility Research Program of the Commission of the
European Communities for a research training fellow-
ship (Contract No. ERBCHBGCT920143), and M.C.R-
.d.A., for a stipendium from the Alexander-von-Humboldt-
Stiftung.
2107(2)
2580(5)
2749(4)
1516(8)
427(4)
88.8(7)
139(3)
109(2)
166(4)
112(2)
150(2)
94.4(14)
94(2)
O(4)
O(5)
O(6)
F(1)
F(2)
F(3)
C(98)
Cl(1)
Cl(2)
Cl(3)
Cl(1′)
Cl(2′)
Cl(3′)
1305(5)
262(4)
9060(7)
9349(4)
8385(11)
10200(5)
9816(5)
10126(6)
8310(7)
-864(3)
877(6)
411(7)
1357(4)
-455(4)
654(5)
80(2)
217(6)
209(5)
107(2)
145(4)
105(3)
Su p p or tin g In for m a tion Ava ila ble: For 3 and 4, tables
giving crystal data and details of the structure determination,
complete atom coordinates and U values, bond lengths and
angles, and anisotropic displacement coefficients (25 pages).
Ordering information is given on any current masthead page.
a
U(eq) is defined as one-third of the trace of the orthogonalized
Uij tensor.
OM950847H
coordination (0-0.2 Å).14,29,30 The same occurs with the
slip angles ψ (the angles between the normal to the
plane through the metal atom and the centroid-metal
(30) (a) Nesmeyanov, A. N.; Ustynyuk, N. A.; Makarova, L. G.;
Andrianov, V. G.; Struchkov, Yu. T.; Andrae, S.; Ustynyuk, Yu. A.;
Malyugina, S. G. J . Organomet. Chem. 1978, 159, 189. (b) Merola, J .
S.; Kacmarcik, R. T.; Van Engen, D. J . Am. Chem. Soc. 1986, 108,
329. (c) Kowalesky, R. M.; Reingold, A. L.; Trogler, W. C.; Basolo, F.
J . Am. Chem. Soc. 1986, 108, 2460. (d) Forschner, T. C.; Cutler, A. R.;
Kullnig, R. K. Organometallics 1987, 6, 889.
(29) Faller, W.; Crabtree, R. H.; Habib, A. Organometallics 1985,
4, 929.