Synthesis, spectroscopic and structural characterization of orthopalladated complexes with 4-phenylbenzoylmethylene triphenyl phosphorane ylide

Article abstract of DOI:10.1007/s11243-010-9372-z

The orthometalated complex [Pd(μ-Cl)(C₆H₅-C ₆H₄C(O)CHPPh₂C₆H₄- κ²-C,C)]₂ (1) was prepared by refluxing in MeOH/CH₂Cl₂ equimolecular amounts of Pd(OAc)₂ and (Ph)₃PCHCOC₆H₄-Ph-4 (=PhBPPY) followed by addition of excess NaCl. Complex 1 reacts with 4-picoline to give the mononuclear derivative [Pd(PhC₆H₄- COCHPPh ₂C₆H₄)(4-picoline)] (2) whose crystal structure has been determined by X-ray diffraction. The precursor complex (1) could not be isolated in a pure form, but it can be used as a starting material for the synthesis of derivatives of mononuclear cyclo-palladated complexes. Orthometallation and ylide C-coordination in complexes 3-5 were characterized by elemental analysis as well as various spectroscopic techniques. Springer Science+Business Media B.V. 2010.

Full text of DOI:10.1007/s11243-010-9372-z

Transition Met Chem (2010) 35:621–626
DOI 10.1007/s11243-010-9372-z
Synthesis, spectroscopic and structural characterization
of orthopalladated complexes with 4-phenylbenzoylmethylene
triphenyl phosphorane ylide
•
•
¨
K. Karami O. Bu¨yu¨kgu¨ngor H. Dalvand
Received: 14 March 2010 / Accepted: 11 May 2010 / Published online: 29 May 2010
Ó Springer Science+Business Media B.V. 2010
Abstract The orthometalated complex [Pd(l-Cl)(C6H5-
C6H4C(O)CHPPh2C6H4-j2-C,C)]2 (1) was prepared by
refluxing in MeOH/CH2Cl2 equimolecular amounts of
Pd(OAc)2 and (Ph)3PCHCOC6H4-Ph-4 (=PhBPPY) fol-
lowed by addition of excess NaCl. Complex 1 reacts with
4-picoline to give the mononuclear derivative [Pd(PhC6H4-
COCHPPh2C6H4)(4-picoline)] (2) whose crystal structure
has been determined by X-ray diffraction. The precursor
complex (1) could not be isolated in a pure form, but it can
be used as a starting material for the synthesis of deriva-
tives of mononuclear cyclo-palladated complexes. Ortho-
metallation and ylide C-coordination in complexes 3–5
were characterized by elemental analysis as well as various
spectroscopic techniques.
metallation. A method for the synthesis of orthopalladated
adducts of the phosphorus ylide Ph3P=CHCO2Me has been
reported [13, 14]. It is possible to obtain orthopalladated
complexes derived from CH activation at Ph rings belonging
to PPh3 moieties. In this work, we describe the synthesis and
characterization of Pd(II) complexes (1–5) of new phos-
phorus ylides (Scheme 1). The X-ray crystal structure of
complex 2 shows both the orthopalladation and ylide C-
coordination in this complex and confirms the endo meta-
lation of the phosphorus ylide.
Experimental
Pd (OAc)2, 2-Bromo-40-Phenylacetophenone, and triphenyl
phosphine were purchased from Merck. The ylides were
synthesized by the reaction of triphenylphosphine with a
chloroform solution of 2-bromo compounds and dehydro-
genated with NaOH [15]. All solvents were reagent grade
and used without further purification. Solution-state 1H and
31P NMR spectra at 300 K were obtained in CDCl3 using a
500 MHz Bruker spectrometer operating at 500.13 MHz
for 1H and 161.97 MHz for 31P and referenced to H3PO4
(85%) for 31P{1H}NMR spectra. IR spectra were recorded
on an FTIR JASCO 680 spectrophotometer, using KBr
disks. Melting points were measured on a Gallenhamp 9B
3707 F apparatus. Elemental analysis for C, H and N was
performed using a Perkin-Elmer 2400 series analyzer.
Introduction
The activation of C–H bonds in organic compounds pro-
moted by transition metals is an important research topic
nowadays [1]. Synthesis of cyclopalladated complexes has
attracted considerable attention by a number of research
groups, due to its implication, in the fundamental steps of
several catalytic cycles, in the functionalization of simple
substrates through orthometallation and in other relevant
chemical processes [2–12]. It is usual to find two or more
C–H bonds in the same compound that can be activated to
K. Karami (&) ꢀ H. Dalvand
Synthesis of PhC6H4COC=HPPh3 (PhBPPY)
Department of Chemistry, Isfahan University of Technology,
Isfahan 84156, I.R. Iran
e-mail: karami@cc.iut.ac.ir
To a dichloromethane solution (15 mL) of 2-bromo 40-
phenyl acetophenone (1.38 g, 5 mmol) was added PPh3
(1.31 g, 5 mmol) and the resulting mixture was stirred for
5 h. The suspension was filtered and the precipitate washed
¨
O. Bu¨yu¨kgu¨ngor
Department of Physics, Faculty of Arts and Sciences,
Ondokuz Mayıs University, 55139 Samsun, Turkey
123

622
Transition Met Chem (2010) 35:621–626
Ph
P
O
M.p. 298 °C (dec); yield (0.234 g, 40%); Anal Found.
for C64H48O2Cl2P2Pd2 C, 63.1; H, 3.8; Calcd C, 64.3; H,
Ph
1
4.0; IR (KBr, cm-1): m (CO) 1,623; H NMR (500 MHz,
H
Endo
Exo
ppm, CDCl3)): d = 4.90 (s, CHP, minor): 4.97 (s, CHP,
major), 7.12–8.12 (m, 4C6H5 ? C6H4CO, both isomers),
31P{1H} NMR (CDCl3, ppm): 18.41 (s br both isomers).
R= Ph
R
O
Ph Ph
P
O
PPh3
i, ii
5
2
4
CH
Pd
Synthesis of [Pd(Cl)(C6H5C6H4C(O)CHPPh2C6
H4-j2-C,C)(4-Picoline)] (2)
3
Ph
1
Ph
Cl
1
2
To a suspension of complex 1 (0.1194 g, 01 mmol) in
dichloromethane (15 cm3) at room temperature, 4-picoline
(0.02 mL, 02 mmol) was added. The suspension gave a
clear solution immediately. After 12-h stirring, the result-
ing solution was filtered over a Celite pad. The solvent was
completely removed by evaporation under vacuum and
CH2Cl2 (2 mL) plus n-hexane (15 mL) or Et2O (7 mL) was
added to give mononuclear complex 2 as a pale green
precipitate, which was filtered off and air-dried.
+2L CH2Cl2
oC, 24 h
2
i)+Pd(O
Ac)2,
C
H2Cl2,60
Ph Ph
P
O
ii) NaCl, MeOH, 12 h
CH
Pd
Cl
Ph
L
L= 4-Picoline( 2), 3-Picoline( 3), Me3Py(4), PPh3 (5)
Scheme 1
Yield: 0.1008 g, 73%; Anal. Found for C32H26NOB-
rClPPd.H2O: C, 53.4; H, 3.4; N, 1.8; Calcd. C, 53.9; H, 3.4;
N, 2.0. IR (KBr, cm-1); m(CO) 1,619; 1H NMR (500 MHz,
CDCl3, ppm): d = 2.13 (s, 3H, Me major isomers), 2.39 (s,
3H, Me minor isomer), 5.16 (br s, 1H, CHP, major isomer),
5.23 (d, 1H, CHP minor isomers, 3JPH = 4 Hz), 6.6 (d, 1H,
with diethyl ether and air-dried. Further treatment with
aqueous NaOH (0.5 M) led to elimination of HBr, giving
free PhBPPY.
M.p. 230–231 °C; Yield: 1.87 g, 82%; IR (KBr, cm-1):
m(CO) 1,507; 1H NMR (500 MHz, CDCl3, ppm): d = 4.52
(d, 1H, CHP, 2JPH = 24 Hz), 7.38 (t 1H, Hp, C6H5) 7.48 (t,
2H, Hm, C6H5), 7.47 (t 2H, Hm, C6H4) 7.53 (m, 6H, Hm,
3
H6, C6H4, JHH = 7.6 Hz major isomer), 6.65 (d, 2H, H5,
H4, C6H4, 3JHH = 5.8 Hz minor isomers), 7.06 (d, 2H, H5,
3
H4, C6H4, JHH = 6 Hz major isomers), 7.10 (m, 1H, H6,
3
PPh3), 7.6 (m, 2H, Ho, C6H5, JHH = 6 Hz), 7.65 (t, 3H,
3
Hp, PPh3, JHH = 6 Hz), 7.84 (m, 6H, Ho, PPh3), 8.08 (d,
C6H4, major isomer), 7.20 (m, 2H, H3, C6H4, both iso-
mers), 7.50 (m, 12H, Hm, PPh2 ? Hm, C6H5 both iso-
mers), 7.60 (m, 8H, Hm, C6H4CO ? Hm, 4-MePy both
isomers), 7.69 (m, 12H, Ho, PPh2 ? Ho, C6H5 both iso-
mers), 7.74 (m, 2H, Hp, C6H5 both isomers), 7.90 (t, 4H,
2H, Ho, C6H4), 31P{1H} NMR (CDCl3): d = 17.2 (s, 1P,
CHP).
13C NMR (CDCl3) d C: 51.3 (d, 1JPC = 111.2 Hz, CH);
125.4 (C6H5 (i)); 126.2 (d, JPC = 93.24 Hz, PPh3 (i));
1
3
126.8 (C6H5 (m)); 127.81 (COPh (m)); 128.4 (C6H5 (p));
128.88 (PPh3 (p)); 129.34 (d, 3JPC = 12.41 Hz, PPh3 (m));
4
128.4 (C6H5 (o)); 131.80 (d, JPC = 2.81 Hz, COPh (o));
Hp, PPh2, JHH = 6 Hz, both isomer), 8.26 (m, 2H, Ho,
4-MePy minor isomers), 8.37 (m, 4H, Ho, C6H4CO both
isomers), 8.41 (m, 2H, Ho, 4-MePy major isomers), 8.62 (d,
2H, Ho, C6H4CO major isomers), 31P{1H} NMR (CDCl3):
d = 15.96 (s, 1P, CHP, minor isomer), 20.32 (s, 1P, CHP,
major isomer). 13C{1H} NMR: d = 21.16, 21.51 (C, Me
both isomer), Caromatic for both isomer {d = 125.48,
125.92, 126.84, 127.04, 127.5, 127.6, 127.7, 128.56,
128.65, 128.95, 129.05, 129.2, 129.4, 129.7, 129.8, 129.9,
130.25, 130.47, 133.11 (d, jPC = 9.56 Hz), 133.32, 133.58
(d, jPC = 9.43 Hz), 136.5, 136.6,136.72}199.2 (CO, both
isomers), 201.8 (CO both isomers).
133.40 (d, 2JPC = 10.25 Hz, PPh3 (o)); 135.86 (COPh (p));
2
2
140.63 (d, JPC = 14.69 Hz, COPh (i)); 185.3 (d, JPC
=
3.3 Hz, CO).
Synthesis of [Pd(l-Cl)(C6H5C6H4C(O)CHPPh2
C6H4-j2-C,C)]2 (1)
Pd(OAc)2 (0.0673 g, 0.3 mmol) was added to a solution of
PhBPPY (0.1365 g, 0.3 mmol) in CH2Cl2 (15 mL) and the
resulting mixture was refluxed overnight. The solvent was
then evaporated and the yellow solid residue was dissolved
in MeOH (10 mL) and anhydrous NaCl (0.0342 g,
0.6 mmol) was added, where upon a pale yellow solid
precipitated immediately. The mixture was stirred for 12 h
at room temperature and the resulting suspension was fil-
tered. The yellow solid was washed with H2O (5 mL) and
Et2O (15 mL) and air-dried to produce complex 1.
Synthesis [Pd(Cl)(C6H5C6H4C(O)CHPPh2
C6H4-j2-C,C)(3-Picoline)] (3)
To a suspension of complex 1 (0.1194 g, 01 mmol) in
dichloromethane (15 cm3) at room temperature, 3-picoline
(0.02 mL. 02 mmol) was added. The resulting suspension
gave a clear solution immediately. After 12-h stirring, the
123

Transition Met Chem (2010) 35:621–626
623
2
resulting solution was filtered over a Celite pad. The sol-
vent was completely removed by evaporation under vac-
uum and CH2Cl2 (2 mL) plus n-hexane (15 mL) or Et2O
(7 mL) was added to give mononuclear complex 3 as a pale
green precipitate, which was filtered off and air-dried.
M.p. 202–204 °C (dec), yield (0.0988 g, 72%), Anal.
Found for C38H31NOClPPd: C, 65.08; H, 4.21; N, 1.91
Calcd C, 66.10; H, 4.52; N, 2.03, IR (cm-1), m (C=O):
1624.73.
3jPC = 9.o5 Hz), 134.96 (d, Co, PPh2, jPC = 10.06 Hz),
3
137.93 (d,C3, jPC = 9.18 Hz), 137.93 (d, C2, jPC
2
=
2
12.83 Hz), 158.47 (d, Co, PPh2, jPC = 10.31 Hz). Other
Caromatic {d = 123.63, 124.1, 126.7, 126.9, 126, 127.23,
127.67, 128.1, 129.1, 130.23, 132.68, 134.48, 139.1,
140.01, 141.03}, 196.2 (CO).
Synthesis of [Pd(Cl)(C6H5C6H4C(O)CHPPh2C6H4-j2-
C,C)(PPh3)] (5)
Complex 3 was characterized (NMR) as a mixture of
two isomers in 1.5/1 M ratio; 1H NMR (500 MHz, CDCl3,
ppm): d = 1.9 (s, Me major isomers), 2.29 (s, Me minor
isomer), 5.19 (brs, 1H, CHP, major isomer), 5.24 (s, 1H,
To a suspension of complex 1 (0.1194 g, 0.1 mmol) in
CH2Cl2 (15 mL) was added PPh3 (0.0524 g, 0.2 mmol).
The initial yellow suspension gradually dissolved, and after
8-h stirring at room temperature, the resulting solution was
filtered over a Celite pad. The clear solution was evapo-
rated to dryness and treatment of the residue with Et2O
(30 mL) gave 5 as a yellow solid.
3
CHP minor isomers, JPH = 4 Hz), 6.55 (d, H6, C6H4,
3JHH = 7.6 Hz minor isomer), 6.65 (dd, H6, C6H4,
3JHH = 6 Hz major isomers), 6.99–7.11 (m, 3H, H5, H4,
H3, C6H4, minor isomer), 7.11–7.13 (m, m, 3H, H5, H4, H3,
C6H4, major isomer), 7.14 (m, H2, 3MePy, both isomers),
7.58-761 (m, 7H, Hm, PPh2 ? Hm ? Hp, C6H5, both
isomers), 7.65–7.72 (m, 10H, Ho,p, PPh2, Hm, C6H4CO ?
Ho, C6H5 both isomers), 7.86 (m, Ho, C6H4CO ? Hp, C6H5
major isomers), 8.39 (m, Ho, C6H4CO ? Hp, C6H5 minor
isomers), 8.42 (m, H4, H5, MePy both isomers ? H6, MePy
minor isomer), 8.25 (d, H6, 3-MePy, 3JH–H = 8.5 Hz major
isomers); 31P{1H} NMR (CDCl3): d = 15.95 (s, 1P, CHP,
minor isomer), 20.43 (s, 1P, CHP, major isomer).
M.p.146 °C; yield (0.1014 g, 59%); Anal found for
C44H34ClFOP2PdCl. C, 65.4; H, 4.0, Calcd C, 65.9; H, 4.3;
IR (KBr, cm-1): m C=O): 1,619 1H NMR (500 MHz,
CDCl3, ppm); d = 5.5 (s, 1H, CHP), 6.5 (m, 2H, C6H4),
6.90 (m, 1H, C6H4), 7.19 (m, 6H, Hm, PPh3), 7.32 (m, 6H,
Hm, PPh2 ? Hm, C6H5), 7.44 (m, 6H, Hp, C6H5
?PPh2 ? PPh3), 7.6 (m, 6H, Ho, PPh3), 7.66 (m, 2H, Hm,
C6H4CO), 7.88 (m, 2H, Ho, C6H5), 8.02 (m, 2H, Ho, PPh2),
8.29 (m, 2H, Ho, PPh2), 8.31 (d, 2H, Ho, C6H4CO,
3JHH = 7.1). 31P{1H} NMR (CDCl3): d 15.09 (s, 1P, CHP),
31.86 (s, 1P, Pd-PPh3).
13C{1H} NMR: d = 21.16, 21.51 (C, Me both isomer),
Caromatic for both isomer {d = 125.48, 125.92, 126.84,
127.04, 127.5, 127.6, 127.7, 128.56, 128.65, 128.95, 129.05,
129.2, 129.4, 129.7, 129.8, 129.9, 130.25, 130.47, 133.11
1
13C{1H}NMR: d = 40.47 (dd, CHP, jPC = 63.13 Hz,
1
2jPC = 21 Hz), 123.72 (d, C1, jPC = 13.20 Hz), C aro-
3
3
(d, jPC = 9.56 Hz), 133.32, 133.58 (d, jPC = 9.43 Hz),
136.5, 136.6, 136.72}, 198.3 (CO, both isomers), 200.3 (CO
both isomers).
matic{d = 126.71, 127.46, 128.12 (d, Co PPh2 or Co PPh3,
3
2jPC = 10.19 Hz), 129.08 (d, Cm PPh2, jPC = 6.03 Hz),
2
129.68 (d, Ci, PPh2, jPC = 11.82 Hz), 130.02, 130.53,
130.66, 131.72, 132.84, 134.64, 138.06, 139.2, 140.8,
3
Synthesis of [Pd(Cl)(C6H5C6H4C(O)CHPPh2C6H4-j2-
C,C)(Me3py)] (4)
144.2}, d = 133.31 (d, C3, jPC = 9.31 Hz), d = 135.16
2
(d, Ci PPh3, jPC = 11.82 Hz), d = 197.5 (CO).
Complex 4 was prepared in a similar manner to complex 3.
Yield (0.0965 g, 67 %); Anal Found for C44H34ClFO-
P2PdCl: C, 65.4; H, 4.0 Calcd C, 65.9; H, 4.3; IR (KBr,
X-ray crystal structure determination
A suitable single crystal was chosen for the crystallo-
graphic study and mounted on the goniometer of a STOE
IPDS II diffractometer. All diffraction measurements were
taken at room temperature (296 K) using graphite mono-
1
cm-1): m C=O): 1,621 H NMR (500 MHz, CDCl3, ppm);
d = 2.10 (s, 3H, Me), 2.27 (s, 3H, Me), 2.96 (s, 3H, Me),
5.27 (d, 1H, CHP, JPH = Hz), 6.57 (d, 1H, H6, C6H4,),
3
˚
chromated MoKa radiation (k = 0.71073 A). The data
6.94 (s, 2H, H5, H4, C6H4), 7.18 (m, 1H, H3, C6H4), 7.40
3
(t, 1H, Me3Py, JHH = Hz), 7.46 (m, 4H, Hm, PPh2), 7.52
collection was performed using the X-scan technique and
using the STOE X-AREA software package [16]. The
crystal structures were solved by direct methods and
refined by full-matrix least-squares on F2 by SHELXL97
[17] and using the ORTEP-3 crystallographic software
package [18]. All non-hydrogen atoms were refined
anisotropically using reflections I [ 2r (I). Hydrogen
atoms were inserted at calculated positions using a riding
mode with fixed thermal parameters.
(t, 2H, Hp, PPh2), 7.60 (m, 1H, Me3Py), 7.69 (m, 7H, Ho,
PPh2 ? Hm, Hp, C6H5) 7.93 (dd, 2H, Hm, C6H4CO), 8.27
(m, 2H, Ho, C6H5), 8.59 (d, 2H, Ho, C6H4CO), 31P{1H}
NMR (CDCl3): d 18.92 (s, 1P, CHP).
13C{1H}NMR: d = 21.14, 26.58, 27.185 (s, 3C, Me), 35
(d, CHP, 1jPC = 59.45 Hz), 124.93 (s, Ci, C6H5), 124.39(d,
1
C1, jPC = 13.20 Hz), 129.625 (d, C6, jPC = 11.95 Hz),
2
1
130.49 (d, Ci PPh2, jPC = 15.22 Hz), 133.78 (d, C5,
123

624
Transition Met Chem (2010) 35:621–626
Results and discussion
(minor) or broad doublet (major). The presence of two
chiral carbon centers (forming diastereoisomers) in 1 was
confirmed using the 1H NMR spectra as two sets of signals
with unequal populations for the CH and PCH groups.
In the 1H NMR spectra of complexes 1–5, the signals due
to the methinic protons are doublets or broad. Similar
behavior was observed earlier in the case of ylide complexes
The IR spectrum of PhBPPY shows a strong absorption at
1,507 cm-1, due to the carbonyl stretch, while the 31H
NMR spectrum shows a doublet at 4.30 ppm assigned to
methinic protons. The absorption due to the carbonyl
stretch appears at lower energies than expected (about
1,720 cm-1), due to the conjugation of the C=O bond with
the P=C bond. The localization of the density charge in the
P–C–C–O bond system is responsible for the stability of
these compounds and can also be inferred from the
31P{1H} NMR spectra [13, 14, 19]. These spectra show a
single peak at about 17.2 ppm, a position shifted to low
field with respect to that observed in other non-stabilized
systems (about 0-6 ppm) and showing the lower shielding
of the P atom in the stabilized compounds due to delo-
calization. The IR spectra of complexes 1–5 show a sharp,
very strong absorption in the 1,618–1,625 cm -1 range (see
Table 1), corresponding to the carbonyl absorption. This
absorption is shifted to higher energies with respect to that
in the free ylide (1,507 cm-1) [1]. The observation of this
positive shift for vCO in the complexes indicates that the
of palladium(II) [19]. The expected downfield shifts of 31
P
and 1H signals for the PCH group upon complexation in the
case of C-coordination were observed in their corresponding
spectra. The 31 P {1H} NMR spectrum of 1 showed two sets
of single peaks at 18.82 (major) and 19.41 ppm (minor). The
presence of two lines of different intensities can be explained
by the presence of two diastereoisomers (RR/SS and RS/SR),
as a result of the C-bonding of the ylide and the binuclear
nature of 1. The bridge-splitting reactions of 2 with neutral
ligands produced exclusively the corresponding mononu-
clear compounds 2–5. The1H and 31P{1H} NMR signals for
the PCH group of all the complexes were shifted downfield in
comparison with those in free ylides, as a consequence of the
2
inductive effects of the metal center. The J(PH) values for
complexes 2–5 were smaller than those in the free ylides and
phosphonium salts; this behavior has already been observed
for other C-coordinated carbonyl-stabilized phosphorus
ylide complexes because the hybridization changes in the
ylidic carbon (Sp2 to Sp3) in the C-coordination mode [20].
1
ylide is C-coordinated to Pd(II). In the H NMR spectrum
of 1, the signals due to the methinic proton were broad
Table 1 Crystal data and structure refinement for complex 5
1
The H NMR spectra of complexes 2 and 3 showed two
Formula
2 (C38 H31Cl N O P Pd)Cl
1416.37
signals for the CH group that are assigned to a fast equilib-
rium between the cis and trans isomers or a dynamic activity
for exchange of Methyl Py and Cl groups in solution [21].
The 1H NMR spectrum of complex 4 showed one signal for
the CH group at 5.16 ppm, while the 31P{1H} NMR spec-
trum shows only one sharp singlet at 18.92 ppm. The
appearance of single signals for the PCH group in each of the
31P and 1H NMR spectra indicates the presence of only one
molecule for this complex, as expected for C-coordination
[1, 22, 23]. The 1H NMR spectrum of complex 5 showed one
signal for the CH group at 5.5 ppm. The 31P{1H} NMR
spectrum of 5 showed two singlet resonances in this case
(range 15.09 and 31.86 ppm), which are shifted to low field
with respect to the parent ylide, in good agreement with the
C-bonding of the ylides.
Formula weight
Crystal system
Triclinic
Space group
P - 1
a
b
10.3826(14)
12.7884(18)
13.8852(17)
110.363(10)
101.145(10)
95.724(11)
1667.6(4)
˚
c (A)
Alpha
Beta
Gamma (°)
3
˚
V (A )
Z
1
D(calc) (g/cm3)
Mu(MoKa) (mm)
F(000)
1.41
0.755
721
The 13C NMR spectra of the complexes 2–5 show
upfield shifts of the signals due to the ylidic carbon atoms.
Such shifts were observed in other complexes, due to the
change in hybridization of the ylidic carbon atom on
coordination [20]. Similar upfield shifts of 2–3 ppm with
reference to the parent ylide were also observed for other
complexes [20, 23]. The 13C shifts of the CO group in the
complexes are between 196 and 202 ppm, which is higher
field than the 185.3 ppm noted for the same carbon in the
parent ylide, indicating much lower shielding of the carbon
atom of the CO group in the complexes. For complex 5, the
Crystal size (mm)
Temperature (K)
0.05 9 0.20 9 0.46
296
˚
Radiation (A)
MoKa 0.71073
1.6, 26.5
Theta min–max (°)
Dataset
-13: 13; -16: 16; -17: 17
16,240, 6,909, 0.109
3480
Tot., Uniq. Data, R(int)
Observed data [I [ 2.0 sigma(I)]
Nref, Npar
6,909, 398
0.0640, 0.1016, 0.90
-0.68, 0.55
R, wR2, S
3
Min. and Max. Resd. Dens. [e/A ]
˚
123

Transition Met Chem (2010) 35:621–626
625
˚
ylidic protons appear as doublets of doublets at
d = 40.47 ppm, meaning that each carbon is coupled with
two different P nuclei (PPh3 and C=P). The coupling
constants (1jPC = 63.13 Hz, 2jPC = 21 Hz) suggest that the
PPh3 is located trans to the ylidic carbon [23], in good
agreement with the expected trans effect between the PPh3
and the arylic carbon [24].
Table 2 Selected bond lengths (A) and angles (°) for complexes 2
Pd1–Cl1
Pd1–N1
2.359(2)
2.136(6)
2.002(6)
2.101(6)
1.803(5)
1.777(6)
1.794(8)
1.775(6)
1.231(7)
1.321(8)
1.340(10)
1.494(8)
1.482(8)
118.1(4)
120.6(5)
Cl1–Pd1–N1
Cl1–Pd1–C7
Cl1–Pd1–C19
N1–Pd1–C7
N1–Pd1–C19
C7–Pd1–C19
C1–P1–C12
C1–P1–C13
C1–P1–C19
C12–P1–C13
C12–P1–C19
C13–P1–C19
Pd1–N1–C33
Pd1–N1–C37
Pd1–C19–P1
88.19(18)
93.6(2)
Pd1–C7
176.76(16
175.8(2)
94.8(2)
Pd1–C19
P1–C1
P1–C12
83.5(3)
P1–C13
110.1(3)
105.4(3)
116.2(3)
111.1(3)
98.2(3)
X-ray crystallography study
P1–C19
O1–C20
N1–C33
N1–C37
C19–C20
C20–C21
P1–C19–C20
O1–C20–C19
The X-ray crystal structure of complex 2 is shown in
Fig. 1. Crystallographic data and parameters concerning
data collection and structure solution and refinement are
115.8(3)
119.5(5)
122.5(5)
97.9(3)
˚
summarized in Table 1 and some selected bond lengths (A)
and angles (°) for complex 2 are collected in Table 2.
These crystals were grown by the diffusion of n-hexane
into a CH2Cl2 solution. In complex 2, each palladium atom
has a slightly distorted square-planar environment, sur-
rounded by the orthometalated C(7) atom, the ylide C(19),
that forms a five-member cycle, one chlorine (Cl1) and one
phosphorus (P1) atom. Complex 2 crystallized in the triclinic
system with space group P - 1. The absolute configuration
of the C(19) atom is depicted in the structure shown in Fig. 1.
The summation of the bond angles around the palladium is
almost 360 °C. Although the orthometallated ligand is
remarkably warped, the environment around the Pd is planar.
bond [25]. The bond length of P(1)–C(19) in the similar ylide
˚
is 1.706 A [1, 26] which shows that the above bond has
˚
considerably elongated to 1.775 (6) A in complex 2. The
˚
Pd1–C19 bond distance (2.101(6) A) in complex 2 with
respect to published examples appears at the low end of the
usual range [(2.090(3)–2.161(8)] [1, 13].
The angles subtended by the ligands at the Pd(II) center
in complex 2 varied from 83.5(3)) to 94.8(2) and 175.8(2)
to 176.76(16), indicating a distorted square-planar envi-
˚
The Pd1-C7 bond distance (2.002(6) A) is similar to those
˚
ronment. The Cl1–Pd1–C19 (176.76(16) A) and N1–Pd1–
found in other ortho-palladated complexes [1, 13] and the
Pd-N(1) distance falls also in the usual range found for this
C7 (175.8(2)) bond angles deviated only a little from
Fig. 1 ORTEP view of the X-
ray crystal structure of complex
2
123

626
Transition Met Chem (2010) 35:621–626
Acknowledgments The authors acknowledge the Department of
Chemistry Isfahan University of Technology and the Faculty of Arts
and Sciences, Ondokuz Mayıs University, Turkey, for the use of the
Stoe IPDSII diffractometer (purchased under grant F. 279 of the
University Research Fund).
Table 3 IR data for PhBPPY and complexes 1–5
Compound
C=O
C=C
C=N
P–C
Ligand PhBPPY
1,507
1,623
1,619
1,625
1,621
1,619
1,566
1,564
1,566
1,564
–
881
839
854
852
[Pd(l-Cl)(PhBPPY)]2 (1)
[PdCl(PhBPPY)4-Picoline)] (2)
[PdCl(PhBPPY)3-Me Py] (3)
[PdCl(PhBPPY)(Me3Py)] (4)
[PdCl(PhBPPY)PPh3] (5)
–
1,601
1,602
1601.6
–
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˚
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˚
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that the cyclopalladation has occurred at one phenyl ring of
the PPh3 (endo) with an additional chiral carbon center.
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dination to the metal center (Table 3).
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Supplementary data
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CCDC 749675 contains the supplementary crystallographic
data for this paper. These data can be obtained free of
charge from The Cambridge Crystallographic Data Centre
via http://www.ccdc.cam.ac.uk/deposit or deposit@ccdc.
cam.ac.uk.
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123