Cyclometallation of 3-Phenyl-6-p-toluidinopyridazine forming a six-membered auracycle and a five-membered palladacycle certified by X-ray analysis

Article abstract of DOI:10.1016/S0277-5387(01)00912-3

3-Phenyl-6-p-toluidinopyridazine (abbreviated as Hptp) was prepared as an ambidentate substrate of cyclometallation. Sodium tetrachloroaurate(III), gold(III) bromide, lithium tetrachloropalladate(II), and rhodium(III) chloride cyclometallated Hptp to give [Au(ptp)Cl₂], [Au(ptp)Br₂], [Pd(ptp)Cl], and [Rh(ptp)₂Cl], respectively. These complexes and [Pd(ptp)Cl(PBu₃)] (PBu₃ = tri-n-butylphosphine) were characterized spectroscopically. The square-planar structures of [Au(ptp)Br₂]·(CH₃)₂SO and [Pd(ptp)Cl(PBu₃)]·CH₃OH were determined by X-ray analysis. Cycloauration preferred forming a six-membered metallacycle while cyclopalladation and cyclorhodation formed five-membered metallacycles.

Full text of DOI:10.1016/S0277-5387(01)00912-3

Polyhedron 20 (2001) 3019–3025
www.elsevier.com/locate/poly
Cyclometallation of 3-phenyl-6-p-toluidinopyridazine forming a
six-membered auracycle and a five-membered palladacycle certified
by X-ray analysis
Matsuo Nonoyama a,*, Kiyohiko Nakajima b, Kiyoko Nonoyama c
a Department of Chemistry, Faculty of Science, Nagoya Uni6ersity, Chikusa, Nagoya 464-8602, Japan
b Department of Chemistry, Aichi Uni6ersity of Education, Igaya, Kariya 448-8542, Japan
c Konan Junior College, Takaya-cho, Konan, Aichi 483-8086, Japan
Received 2 May 2001; accepted 22 August 2001
Abstract
3-Phenyl-6-p-toluidinopyridazine (abbreviated as Hptp) was prepared as an ambidentate substrate of cyclometallation. Sodium
tetrachloroaurate(III), gold(III) bromide, lithium tetrachloropalladate(II), and rhodium(III) chloride cyclometallated Hptp to give
[Au(ptp)Cl2], [Au(ptp)Br2], [Pd(ptp)Cl], and [Rh(ptp)2Cl], respectively. These complexes and [Pd(ptp)Cl(PBu3)] (PBu3=tri-n-
butylphosphine) were characterized spectroscopically. The square-planar structures of [Au(ptp)Br2]·(CH3)2SO and
[Pd(ptp)Cl(PBu3)]·CH3OH were determined by X-ray analysis. Cycloauration preferred forming a six-membered metallacycle
while cyclopalladation and cyclorhodation formed five-membered metallacycles. © 2001 Published by Elsevier Science Ltd.
Keywords: Cycloauration; Cyclopalladation; Cyclorhodation; 3-Phenyl-6-p-toluidinopyridazine
1. Introduction
6-p-toluidinopyridazine (abbreviated as Hptp, Fig. 1)
having two metallating sites 2% (phenyl ring) and 2¦
(p-tolyl group) which will result in forming a five- or a
six-membered metallacycle, respectively (Fig. 2(A) and
(B)). Double cyclometallation is also expected (Fig.
2(C)). Equimolar reactions of Hptp with sodium tetra-
chloroaurate(III) and lithium tetrachloropalladate(II)
gave a six- and five-membered metallacycle, respectively
(Fig. 2) but double cyclometallation was, so far, not
achieved. To augment our knowledge, the reaction with
Rh(III)Cl3·3H2O was also carried out. Au(III) and
Pd(II) have a d8 electron configuration and are expected
to form square-planar complexes but Rh(III) has a d6
electron configuration and will form octahedral
complexes.
Cyclometallation is a procedure for activating di-
rectly the CꢀH bonds of organic molecules bearing
suitable donor groups with appropriate metal com-
pounds (metal=Pd, Rh, Pt, etc.) and in general, occurs
preferably for substrates forming five-membered metal-
lacycles [1]. Contrary to the well-developed area, direct
cycloauration reported recently concerns, in many
cases, six-membered metallacycles [2]. Such six-mem-
bered auracycles are, e.g. formed upon direct cycloaura-
tion of 2-benzylpyridine, 2-anilinopyridine, etc. while
many five-membered auracycles have been obtained
indirectly by transmetallation from the corresponding
organomercury compounds: mercurated N,N-dimethyl-
benzylamine, azobenzene, etc. [3]. It looks as if cycloau-
ration prefers forming a six-membered metallacycle. We
are interested in this point and have prepared 3-phenyl-
2. Results and discussion
The reaction of 3-chloro-6-phenylpyridazine with p-
toluidine in refluxing xylene gave 3-phenyl-6-p-tolu-
idinopyridazine (Hptp: atom-labeling scheme for NMR
spectra is given in Fig. 1) which was characterized by
* Corresponding author. Tel.: +81-52-789-2475; fax: +81-52-789-
5913.
E-mail address: nonoyama@chem4.chem.nagoya-u.ac.jp (M.
Nonoyama).
0277-5387/01/$ - see front matter © 2001 Published by Elsevier Science Ltd.
PII: S0277-5387(01)00912-3

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M. Nonoyama et al. / Polyhedron 20 (2001) 3019–3025
the IR, H and 13C{1H} NMR [in dimethylsulfoxide-d6
(dmso-d6)] spectra. Hptp reacted in an equimolar ratio
with sodium tetrachloroaurate(III) and gold(III) bro-
mide in a refluxing mixture of water and ethanol to give
[Au(ptp)Cl2] and [Au(ptp)Br2], respectively, and with
lithium tetrachloropalladate(II) in refluxing methanol
[Pd(ptp)Cl]. Attempted double cyclometallation of
Hptp with the two equivalent metal salts resulted in
single cyclometallation: [Au(ptp)Cl2] and [Pd(ptp)Cl]2
PdCl2 were obtained (the structure of the latter remains
unexplained so far). Only monopalladation was re-
ported for ligands potentially capable of undergoing
double cyclopalladations, 3,6-diphenoxypyridazine and
4,6-diphenoxypyrimidine[4]. [Pd(ptp)Cl], the structure
of which may be a Cl-bridged dimer as established
generally for the related cyclopalladated complexes [1],
did not give any suitable crystals for X-ray analysis and
then the tri-n-butylphosphine (PBu3) derivative,
[Pd(ptp)Cl(PBu3)], was prepared.
tained but that of the p-tolyl group was altered appear-
ing as two doublets and one singlet. In the 13C{1H}
NMR spectra the number of peaks is consistent with
1
1
the H NMR results: six peaks were observed for the
phenyl group and four for the p-tolyl in Pd complexes
while vice versa in Au complexes. These facts suggest
the modes of metallation shown in Fig. 2 ((A) for Au
and (B) for Pd).
In the IR spectra (Nujol mulls) of the above com-
plexes, the presence of w(NH) bands indicates that the
amino groups remain intact. In the w(CN) region of the
secondary aromatic amino groups, two medium-strong
bands were observed for free Hptp (1324 and 1372
cm−1) and similarly two for [Pd(ptp)Cl] (1355 and 1377
cm−1). For [Au(ptp)X2] (X=Cl, Br), however, only
one band was observed (1377 (Cl) and 1378 (Br)
cm−1). The fact indicates different modes of coordina-
tion of the ligand towards the two metals. In the
spectrum of [Pd(ptp)Cl] a characteristic band of five
adjacent ring H atoms of free Hptp at 698 cm−1 was
absent in the region of aromatic ring CꢀH out-of-plane
deformation vibrations sensitive to ring substitution
modes [5], while the band persisted in those of
[Au(ptp)X2]: 685 (Cl) and 694 (Br) cm−1. These facts
indicate that auration occurred at the p-tolyl group
incorporating the amino group in a chelate ring and
retaining the phenyl substituent intact (Fig. 2(A)) and
that palladation occurred at the phenyl ring without the
participation of the p-toluidino group (Fig. 2(B)) in
agreement with the NMR results. The low energy
bands of w(MꢀX) are consistent with the structures
where X is coordinated trans to the metallated carbon
donor with a strong trans influence.
1
The H NMR spectra of the complexes revealed that
one aromatic proton was lost upon coordination and
that the NH group was left intact. The H chemical
1
shifts of NH differed markedly between the Pd and Au
complexes, suggesting the NH groups in different sur-
roundings. The spectral pattern due to the aromatic
ring protons also differed between the Pd and Au
complexes. For Pd complexes the pattern of the p-tolyl
group was retained but that of the phenyl group was
altered, the latter being similar to those of the orthopal-
ladated phenyl moieties reported in Ref. [4]. For Au
complexes, the pattern of the phenyl group was re-
The square-planar structure of [Au(ptp)Br2]·
(CH3)2SO in Fig. 3 is characterized with a six-mem-
bered auracycle and the overall structure is similar to
that reported for [Au(anp)Cl2] (Hanp=2-anilinopy-
ridine) [6,7]. The selected bond distances and bond
angles are given in Table 1. One mole of dmso was
included as a solvent of crystallization and the S atom
was disordered. The O atom holds to N(3) through a
Fig. 1. Structure of 3-phenyl-6-p-toluidinopyridazine (Hptp) and
atom-labeling scheme for NMR spectra.
,
hydrogen bond {N(3)ꢀO(1) 2.75(1) A}. The AuꢀBr
lengths reflected the strong trans influence of the au-
rated carbon atom: the length trans to the carbon atom
,
was approximately 0.12 A longer than that trans to the
nitrogen atom. The six-membered auracycle adopted a
boat conformation and both Au(1) and N(3) are, re-
,
spectively, 0.75(2) and 0.27(1) A out of the mean plane
defined by C(1), C(11), C(12) and N(1). The H(8) on
,
C(13) is calculated to be close to Br(1) {2.81 A} within
,
the sum of the van der Waals radii (1.20+1.85 A) and
the unfavorable contact is relieved by the boat confor-
mation, the aurated aromatic ring {C(11)ꢀC(16)} mak-
ing a dihedral angle of 36.4(3)° with the coordination
plane {Au(1), Br(1), Br(2), C(12) and N(1)}. The angle
86.9(4)° at Au in the chelate ring is small as for
Fig. 2. Three modes of cyclometallation.

M. Nonoyama et al. / Polyhedron 20 (2001) 3019–3025
3021
[Pd(CꢀN)XP] (X=a halogen donor and P=a phos-
phorus donor) [1]. The coordination bond distances
and bond angles around the Pd atom are normal for
these type of complexes: the long PdꢀCl bond is due to
the strong trans influence of the trans carbon donor
C(6) [9], and the PdꢀN(1) is longer than the
PdꢀN(pyridine-like) bonds in PdN4-type complexes [10]
reflecting the strong trans influence of the trans PBu3
ligand. The acute N(1)ꢀPd(1)ꢀC(6) angle of 80.9(4)°
reflects a strained five-membered palladacycle. This
complex also shows a similar asymmetric tendency as
above between the two NꢀC bond distances of the
aniline-like N(3) atom. The coordination plane is tetra-
hedrally distorted slightly {displacements form the
mean plane: N(1)+0.207(8), C(6)−0.15(1), P(1)+
,
0.030(1), and Cl(1) and Pd(1)B0.01 A}. The palladated
ring {C(5)ꢀC(10)} makes a dihedral angle of 12.2(4)°
with the coordination plane. The angle between the
palladated and pyridazine rings is 6.4(5)°, slightly larger
than the corresponding angle {3.1(5)°} of [Au(ptp)Br2],
where the moiety is free.
Table 1
,
Selected bond lengths (A) and bond angles (°)
[Au(ptp)Br2]·(CH3)2SO
Fig. 3. ORTEP diagram for [Au(ptp)Br2]·(CH3)2SO with atom labeling
scheme. The hydrogen atoms and (CH3)2SO are omitted for clarity.
Bond lengths
Au(1)ꢀBr(1)
Au(1)ꢀN(1)
N(1)ꢀC(1)
N(3)ꢀC(11)
N(1)ꢀN(2)
C(4)ꢀC(5)
2.402(1)
2.001(7)
1.33(1)
1.42(1)
1.37(1)
1.48(1)
Au(1)ꢀBr(2)
Au(1)ꢀC(12)
C(1)ꢀN(3)
C(11)ꢀC(12)
N(2)ꢀC(4)
C(5)ꢀC(6)
2.518(1)
1.990(9)
1.38(1)
1.39(1)
1.34(1)
1.41(1)
the usual six-membered chelate rings and reflects the
boat conformation. The NꢀC lengths around the ani-
,
line-like N(3) atom are asymmetric: 1.38(1) A for C(1)
,
of the heterocycle and 1.42(1) A for C(11) of the phenyl
Bond angles
Br(1)ꢀAu(1)ꢀBr(2)
Br(2)ꢀAu(1)ꢀN(1)
Au(1)ꢀC(12)ꢀC(11) 121.8(6)
C(12)ꢀC(11)ꢀN(3) 122.2(8)
N(3)ꢀC(1)ꢀN(1)
C(6)ꢀC(5)ꢀC(4)
C(6)ꢀC(5)ꢀC(10)
ring. A similar trend was also found in the structures of
[Au(anp)Cl2] and those of non-metallated 2-(1-naphthy-
lamino)pyridine and 2-anilinopyridine [8]. The phenyl
substituent of the pyridazine ring C(4) exerted no ap-
preciable effect on the structure. The phenyl and pyrid-
azine rings make only a small dihedral angle of 3.1(5)°.
The large angle of 30.9(4)° between the aurated aro-
matic and pyridazine rings compared with that
{9.2(4)°} of the corresponding fragment in [Pd-
Cl(ptp)(PBu3)] should result from the chelation of the
fragment.
89.24(4) Br(1)ꢀAu(1)ꢀC(12)
91.8(2)
91.9(3)
86.9(4)
125.1(6)
123.5(7)
114.0(8)
121.6(9)
N(1)ꢀAu(1)ꢀC(12)
Au(1)ꢀN(1)ꢀC(1)
C(11)ꢀN(3)ꢀC(1)
N(2)ꢀC(4)ꢀC(5)
C(4)ꢀC(5)ꢀC(10)
119.8(7)
119.8(9)
118.4(9)
C(12)ꢀC(11)ꢀC(16) 121.9(8)
[Pd(ptp)Cl(Pbu3)]·CH3OH
Bond lengths
Pd(1)ꢀCl(1)
Pd(1)ꢀN(1)
C(6)ꢀC(5)
C(4)ꢀC(5)
N(2)ꢀC(1)
N(3)ꢀC(11)
2.406(3)
Pd(1)ꢀP(1)
Pd(1)ꢀC(6)
N(1)ꢀC(4)
N(1)ꢀN(2)
C(1)ꢀN(3)
C(11)ꢀC(16)
2.277(3)
2.02(1)
1.34(1)
1.34(1)
1.37(1)
1.41(1)
2.104(8)
1.40(1)
1.48(1)
1.33(1)
1.40(1)
The structure of [PdCl(ptp)(PBu3)]·CH3OH was also
square-planar (Fig. 4) but a five-membered palladacycle
was formed in the complex. The selected bond distances
and the bond angles are given in Table 1. One mole of
methanol was contained as a solvent of crystallization
and the O atom was involved in hydrogen bond with
Bond angles
Cl(1)ꢀPd(1)ꢀP(1)
P(1)ꢀPd(1)ꢀC(6)
Pd(1)ꢀC(6)ꢀC(5)
C(6)ꢀC(5)ꢀC(4)
N(3)ꢀC(1)ꢀN(2)
C(12)ꢀC(11)ꢀN(3) 117(1)
C(6)ꢀC(5)ꢀC(10) 122(1)
91.7(1)
95.9(3)
113.7(8)
116(1)
Cl(1)ꢀPd(1)ꢀN(1)
N(1)ꢀPd(1)ꢀC(6)
Pd(1)ꢀN(1)ꢀC(4)
N(1)ꢀC(4)ꢀC(5)
C(11)ꢀN(3)ꢀC(1)
C(16)ꢀC(11)ꢀN(3) 127(1)
C(12)ꢀC(11)ꢀC(16) 116(1)
92.1(2)
80.9(4)
113.6(7)
115(1)
,
HN(3) {O(1)ꢀN(3) 2.87(1) A}. The tip parts of the Bu
group of PBu3 are considerably disordered. The pal-
ladacycle was nearly planar and the Cl atom was
coordinated trans to the palladated carbon atom, as
usually observed in related cyclopalladated complexes,
121.8(9)
129.0(9)

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M. Nonoyama et al. / Polyhedron 20 (2001) 3019–3025
Fig. 4. ORTEP diagram for [Pd(ptp)Cl(PBu3)]·CH3OH with atom labeling scheme. The hydrogen atoms and CH3OH are omitted for clarity.
the IR spectrum the region of NH vibrations was
interfered by the presence of water and several peaks
appeared. The characteristic band of the five adjacent
aromatic ring H atoms of free Hptp at 689 cm−1
disappeared as in [PdCl(ptp)]. Two bands at 244 and
Comparison of the structural parameters of the ptp
ligands between the two structures reveals that bond
distances differ only slightly while bond angles and
conformations differ significantly (Table 1). Metallation
deformed the benzene rings: the interior angle at the
ipso carbon, C(5) (Pd) and C(11) (Au), became obtuse
while that at the metallated carbon, C(6) (Pd) and
C(12) (Au), became acute [from 120(1) to 115(1)° for
Pd and from 122(1) to 115.8(8)° for Au] in the coordi-
nated rings compared with the uncoordinated ones. The
auration at C(12) {or C(16)} decreases the angle,
C(1)ꢀN(3)ꢀC(11), and one of the external angles at
C(11) compared with the corresponding angles in
[Pd(ptp)Cl(PBu3)], where the part is free from metalla-
cycle, an analogous change is induced at C(5) upon
palladation of C(6) {or C(10)}. The angle deformations
should be accompanied by conformation changes: as
indicated above, upon cyclometallation the dihedral
angles between the benzene and pyridazine rings are
altered compared with that when the part is free.
In addition to the above 1:1 complexes, the 1:2
complex formulated as [Rh(ptp)2Cl]·1.5H2O was ob-
tained by the reaction of Hptp with RhCl3·3H2O in a
2:1 molar ratio. The 1:1 reaction product could not be,
however, identified so far. The IR, 1H and 13C{1H}
NMR (in dmso-d6) spectra of [Rh(ptp)2Cl]·1.5H2O were
complicated compared with those discussed above. In
1
302 cm−1 may be assigned to w(RhꢀCl). The H and
13C{1H} NMR spectra can be interpreted as a superim-
position of signals of the two ptp in slightly different
environments, each sets of the signal patterns being
assigned to the structure in Fig. 2(B) (the phenyl ring
cyclometallation like the Pd complex). The complex
should exist as [Rh(ptp)2Cl(dmso-d6)] in a dmso-d6 so-
lution, the two ptp ligands not being equivalent: e.g.
l(NH) at 10.72 and 10.31; l(CH3) at 2.24 and 2.31;
and l(CH3) at 20.4 and 20.6 ppm. The rhodated car-
bon signals were observed as the two doublets at 162.9
{J(RhC) 35.0 Hz} and 164.7 {36.1} ppm. The structure
in the solid state may be a Cl-bridged dimer with cis-C
and trans-N disposition as generally found for cy-
clorhodated [Rh(CꢀN)2(v-Cl)]2-type complexes [11,12].
Until now, several attempts failed to obtain crystals
suitable for X-ray analysis.
The ambidentate substrate, Hptp, was cyclometal-
lated with gold(III) to form a six-membered auracycle
while with Pd(II) and Rh(III) a five-membered pallada-
and rhoda-cycle, respectively. The factors causing the
regioselectivity are not clear at present and further
studies are in progress to solve the problem.

M. Nonoyama et al. / Polyhedron 20 (2001) 3019–3025
3023
3. Experimental
3.2.3. [Au(ptp)Br2]
Reaction of 473 mg (1 mmol) of AuBr3·2H2O with
261 mg (1 mmol) of Hptp in similar conditions as
above gave 97 mg (16%) of a yellow powder. M.p.
(dec.) 207–209 °C. Gold mirror appeared on the reac-
tion vessel and this might have lowered the yield. Calc.
for C17H14N3Br2Au: C, 33.09; H, 2.29; N, 6.81. Anal.
Found: C, 32.86; H, 2.28; N, 6.65%. IR (Nujol, cm−1):
3.1. Measurements
Measurements were carried out by the methods re-
ported earlier [6]. Abbreviations: tl=p-tolyl, pd=pyri-
dadinyl, and ph=phenyl; s=singlet, d=doublet,
t=triplet, m=multiple, and br=broad. Signals of
13C{1H} NMR spectra were singlet unless otherwise
indicated. The intensity of each signal was indicated in
parentheses, if necessary.
1
w(NH) 3290; w(AuBr) 254, 193. H NMR (dmso-d6, l
ppm): 2.34s (3H, CH3); 7.12d, 7.16d, 7.66s (tl); 7.83d,
8.39d (pd); 7.59m (3H), 8.18m (2H) (ph); 11.3s (NH).
13C{1H} NMR (l ppm): 20.5 (CH3); 122.3 (CꢀAu),
117.1, 129.7, 136.2 (tl); 124.0, 239.1, 147.4, 151.3 (pd);
126.8(2C), 129.0(2C), 130.5 (ph); 133.9 (2C), 128.2
(quaternary C of ph and tl). Recrystallization from hot
dmso gave crystals suitable for X-ray analysis.
3.2. Preparation
3.2.1. 3-Phenyl-6-p-toluidinopyridazine
A mixture of 5.00 g (26.2 mmol) of 3-chloro-6-
phenylpyridazine and 2.81 g (26.2 mmol) of p-toluidine
in 30 cm3 of xylene was heated in an oil bath at 150 °C
with continuous stirring for 6 h. The oil bath was
removed and after the mixture was cooled briefly, 30
cm3 of water was added cautiously with stirring fol-
lowed by 4.00 g of solid sodium hydroxide. To the
mixture cooled to room temperature (r.t.) 50 cm3 of
dichloromethane was added and the suspension was
stirred until the brown lump was loosened to a yellow
powder. The powder was filtered, washed with water
and ethyl ether, dried in air, and recrystallized from hot
acetone to give light yellow crystals. Yield: 4.92 g
(72%). M.p. (dec.) 218–219 °C. Calc. for C17H15N3: C,
78.13; H, 5.79; N, 16.08. Anal. Found: C, 77.80; H,
5.74; N, 16.41%. IR (Nujol, cm−1): w(NH) 3180, 3230.
1H NMR (dmso-d6, l ppm): 2.33s (3H, CH3); 7.20d
(2H), 7.75d (2H) (tl); 7.26d, 8.02d (pd); 7.48t, 7.56t
(2H), 8.11d (2H) (ph); 9.38s (NH). 13C{1H} NMR (l
ppm): 20.4 (CH3), 118.9 (2C), 129.2 (2C), 130.3, 138.2
(tl); 116.6, 125.3, 151.3, 156.6 (pd); 125.7 (2C), 128.8,
128.9 (2C), 136.6 (ph).
3.2.4. [Pd(ptp)Cl]
A mixture of 261 mg (1 mmol) of Hptp and
Li2[PdCl4], prepared in situ from 177 mg (1 mmol) of
PdCl2 and 85 mg (2 mmol) of LiCl in 30 cm3 of
methanol, was stirred overnight and then refluxed for 6
h. After cooling, the product was filtered, washed with
methanol, and dried in air. The product was refluxed
with 300 cm3 of CH2Cl2 with stirring for 30 min and the
undissolved material was collected, washed with
CH2Cl2, and dried in air. Yield: 288 mg (72%). M.p.
(dec.) 282 °C. Calc. for C17H14N3ClPd: C, 50.77; H,
3.51; N, 10.45. Anal. Found: C, 50.81; H, 3.55; N,
10.42%. IR (Nujol, cm−1): w(NH) 3402, 3386; w(PdCl)
250, 239. 1H NMR (dmso-d6, 373 K, l ppm): 2.31s (3H,
CH3); 7.15d (2H), 7.70d (2H) (tl); 7.40d, 8.03d (pd);
6.97td, 7.09td, 7.44dd, 7.79d (ph); 9.25s (NH). 13C{1H}
NMR (373 K, l ppm): 19.7 (CH3); 119.1 (2C), 128.6
(2C), 130.8, 136.9 (tl); 119.7, 125.1, 154,7, 159.0 (pd);
122.6, 123.8, 127.0, 135.2, 141.8, 149.7 (CꢀPd) (ph).
3.2.5. Attempted double cyclometallation
The reaction of 261 mg (1 mmol) of Hptp and 796
mg (2 mmol) of Na[AuCl4]·2H2O under the conditions
used for the synthesis of [Au(ptp)Cl2] precipitated a
yellow powder analyzed as [Au(ptp)Cl2]·C2H5OH (272
mg, 95%). Calc. for C19H20N3OCl2Au: C, 39.74; H,
3.51; N, 7.32. Anal. Found: C, 39.33; H, 3.31; N,
7.27%. Recrystallization of the powder from acetone
gave the same complex as above.
3.2.2. [Au(ptp)Cl2]
A mixture of 398 mg (1 mmol) of Na[AuCl4]·2H2O
and 261 mg (1 mmol) of Hptp in a mixture of 15 cm3
of water and 15 cm3 of ethanol was refluxed overnight
with stirring. After cooling, the product was filtered,
washed with water and ethanol, dried in air, and recrys-
tallized from acetone to give 425 mg (80%) of a yellow
powder. M.p. (dec.) 233–234 °C. Calc. for
C17H14N3Cl2Au: C, 38.66; H, 2.67; N, 7.96. Anal.
Found: C, 38.41; H, 2.60; N, 7.87%. IR (Nujol, cm−1):
The reaction of 261 mg (1 mmol) of Hptp and
Li2[PdCl4], prepared in situ from 355 mg (2 mmol) of
PdCl2 and 170 mg (4 mmol) of LiCl in 30 cm3 of
methanol, under the above conditions for the synthesis
of [Pd(ptp)Cl] formed a brown powder of the composi-
tion [Pd(ptp)Cl]2·PdCl2 (209 mg, 85%). M.p. (dec.)
295 °C. Calc. for C34H28N6Pd3Cl4: C, 41.60; H, 2.87;
N, 8.56. Anal. Found: C, 41.79; H, 2.98; N, 8.31%. IR
(Nujol, cm−1): w(NH) 3330, 3321; w(PdCl) 354, 340,
1
w(NH) 3212, 3230; w(AuCl) 354, 283. H NMR (dmso-
d6, l ppm): 2.35s (3H, CH3); 7.13d, 7.16d, 7.51s (tl);
7.84d, 8.38d (pd); 7.59m (3H), 8.15d (2H) (ph); 11.4s
(NH). 13C{1H} NMR (343 K, l ppm): 20.1 (CH3);
120.1 (CꢀAu), 116.9, 129.3, 133.5 (tl); 123.8, 128.6,
146.8, 151.3 (pd); 126.5 (2C), 128.6 (2C), 130.0 (ph);
128.4, 133.6 133.7 (quaternary C of ph and tl).
1
263. The H and 13C{1H} NMR spectra (dmso-d6) were
identical to those of [Pd(ptp)Cl].

3024
M. Nonoyama et al. / Polyhedron 20 (2001) 3019–3025
3.2.6. [Pd(ptp)Cl(PBu3)]
with stirring. After cooling to r.t., a yellow orange
precipitate was filtered, washed with ethanol, and dried
in air. The product was dissolved in 3 cm3 of dmso on
a hot plate at 128 °C, and the solution was filtered and
allowed to cool to r.t. A precipitate was collected,
washed with a small amount of dmso and then with
methanol to afford 251 mg (37%) of a yellow–orange
powder formulated as [Rh(ptp)2Cl]·1.5H2O. M.p. (dec.)
280 °C. Calc: for C34H31N6O1.5ClRh: C, 59.53; H, 4.55;
N, 12.25. Anal. Found: C, 59.74; H, 4.62; N, 12.14%.
1H NMR (dmso-d6, l ppm): 2.24s, 2.31s (CH3); 5.77d,
6.96d, 7.17d, 7.68d (tl); 7.10d, 8.24d, 7.60d, 8.41d (pd),
6.33d, 6.38d, 6.48t, 6.89t, 6.90t, 6.96t, 7.65d, 7.70d (ph);
10.31s, 10.72s (NH). 13C{1H} NMR (dmso-d6, l ppm):
20.4, 20.6 (CH3):119.2(2C), 122.5(2C), 129.1(2C),
129.8(2C) (tl); 118.0, 120.7, 122.3, 122.8, 124.1, 124.7,
127.2, 128.1, 128.7, 129.1, 131.8, 133.7 (CH); 132.6.
135.0, 134.0, 136.7, 140.2, 140.9, 155.3, 159.4,
To a suspension of 1 mmol (402 mg) of [Pd(ptp)Cl] in
30 cm3 of dichloromethane 1 mmol (202 mg) of PBu3
was added and the mixture was stirred for 30 min at r.t.
The solution was treated with Florisil and filtered. The
filtrate was concentrated to a small volume and mixed
with 20 cm3 of hexane to precipitate the product. Yield:
276 mg (46%). M.p. (dec.) 191–192 °C. Calc. for
C29H41N3ClPPd: C, 57.62; H, 6.84; N, 6.95. Anal.
Found: C, 57.68; H, 6.92; N, 6.88%. IR (Nujol, cm−1):
1
w(NH) 3276; w(PdCl) 255. H NMR (CDCl3, 298 K, l
ppm): 2.26s (3H, CH3); 0.86t (9H), 1.41m (6H), 1.62m
(6H), 2.07m (6H) (Bu); 7.04d (2H), 7,53d (2H) (tl);
7.08m (2H), 7.18dd (1H), 7.27m (1H) (ph); 7.37d (1H),
7.40d (1H) (pd); 7.58br (NH). 13C{1H} NMR (CDCl3,
298 K, l ppm): 20.3 (CH3); 13.7, 24.1d (28.2), 24.2d
(13.9), 29.6 (Bu); 120.9(2C), 129.7(2C), 132.7, 136.5 (tl);
123.6, 124.5, 128.6d (4.6), 135.7d (9.3), 144.4, 156.0d
(5.7) (CꢀPd) (ph); 118.2, 124.7, 154.7, 159.6d (1.2) (pd)
ppm [figures in parentheses are J(PꢀC) in Hz]. Crystals
for X-ray analysis were obtained by recrystallization
from a mixture of dichloromethane and methanol.
158.6{2.9},
159.7{3.0}
(quaternary
carbons);
162.9{35.0}, 164.7{36.1} (CꢀRh). Figures in braces are
J(RhꢀC) in Hz. Several attempts to obtain crystals
suitable for X-ray analysis failed.
3.3. Crystallographic analysis
3.2.7. [Rh(ptp)2Cl]
To a solution of 1 mmol (263 mg) of RhCl3·3H2O in
30 cm3 of 2-methoxyethanol, 2 mmol (523 mg) of Hptp
was added and the mixture was refluxed for six days
The crystallographic data for [Au(ptp)Br2]·(CH3)2SO
and [Pd(ptp)Cl(PBu3)]·CH3OH are given in Table 2. A
prismatic red crystal of [Au(ptp)Br2]·(CH3)2SO with
dimensions of 0.20×0.25×0.33 mm was glued onto a
glass fiber and coated with epoxy resin. A prismatic
yellow crystal of [Pd(ptp)Cl(PBu3)]·CH3OH with di-
mensions of 0.10×0.20×0.30 mm was sealed in a
glass capillary tube together with the mother liquor.
X-ray diffraction data were collected at 25 °C on a
Rigaku RAXIS-RAPID diffractometer with graphite-
Table 2
Crystal data and structure refinement parameters for [Au(ptp)Br2]·
(CH3)2SO and [Pd(ptp)Cl(PBu3)]·CH3OH
[Au(ptp)Br2]·
[Pd(ptp)Cl(PBu3)]·
(CH3)2SO
CH3OH
Empirical formula
Formula weight
Crystal system
Space group
Unit cell dimensions
C
695.22
triclinic
P1
19H20AuBr2N3OS C30H45ClN3OPPd
,
636.53
monochromated Mo Ka radiation (u=0.71069 A). A
monoclinic
P21/n
total of 44 images was collected with two different
goniometer settings (2qmax=55°). Exposure time was 3
min per degree, and the readout was performed in 0.100
mm pixel mode. The diffraction data were processed by
the PROCESS-AUTO program package. After the removal
of the redundant data, a set of 4387 reflections [I\
2|(I)] for [Au(ptp)Br2]·(CH3)2SO and 2608 reflections
[I\2|(I)] for [Pd(ptp)Cl(PBu3)]·CH3OH were used for
the structure determination. A numerical absorption
correction was applied to the data using the NUMABS
program [13]. For each of the data sets the positions of
the heavy atoms were found by the direct methods
(
,
a (A)
10.9151(2)
12.6283(7)
9.9454(6)
90.007(5)
115.602(5)
65.908(4)
1102.4(1)
2
10.5111(3)
20.1628(2)
15.8599(3)
,
b (A)
,
c (A)
h (°)
i (°)
k (°)
V (A )
100.320(3)
3
,
3306.9(1)
4
Z
Absorption coefficient
103.56
7.15
(cm−1
)
Crystal color
Dcalc (g cm−3
2q Range (°)
R
red
2.094
55
0.060
0.085
yellow
1.278
55
0.062
0.078
1.47
)
(SIR-92) [14], and subsequent cycles of full-matrix least-
square refinement followed by difference Fourier syn-
theses (DIRDIF-94) [15] revealed the positions of the
remaining non-hydrogen atoms. In the final refinement
cycles all the non-hydrogen atoms were refined an-
isotropically and the hydrogen atoms were included in
the refinement with idealized parameters. In each com-
plex a hydrogen atom bound to the N(3) atom and
Rw
S, Goodness-of-fit on F2 1.82
2 1/2
R=ꢀꢁ ꢁFoꢁ−ꢁFcꢁ ꢁ/ꢀꢁFoꢁ;
Rw=[ꢀw(ꢁFoꢁ−ꢁFcꢁ)2/ꢀwꢁFoꢁ ]
;
w=
[|c2(Fo)+(p2/4)ꢁFoꢁ2]−1; p=0.0700 for [Au(ptp)Br2]·(CH3)2SO and
0.0600 for [Pd(ptp)Cl(PBu3)]·CH3OH; S=[ꢀw(ꢁFoꢁ−ꢁFcꢁ)2/(m−n)]1/2
(m=number of used reflections, n=number of refined parameters).

M. Nonoyama et al. / Polyhedron 20 (2001) 3019–3025
3025
those of the solvent of crystallization were not located.
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4. Supplementary material
Crystallographic data for structural analysis have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC Nos. 163482 and 163483 for
[Au(ptp)Br2]·(CH3)2SO and [Pd(ptp)Cl(PBu3)]·CH3OH,
respectively. Copies of this information may be ob-
tained free of charge from The Director, CCDC, 12
Union Road, Cambridge, CB2 1EZ, UK (fax: +44-
1223-336033; e-mail: deposit@ccdc.cam.ac.uk or www:
http://www.ccdc.cam.ac.uk).
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Acknowledgements
The authors thank the Analytical Chemistry Labora-
tory, Faculty of Science, Nagoya University for allow-
ing them to use the Bruker NMR spectrometer. The
present work was partially supported by a Grant-in-Aid
(Scientific Research No. 13640557) from the Ministry
of Education, Science, and Culture.