Synthesis and properties of arylpalladium(II) azido complexes PdAr(N3)(PR3)2. Nucleophilic reactions of the azido ligand with CO and with isocyanides to afford Pd(II) isocyanate, C-tetrazolate and carbodiimide complexes

Article abstract of DOI:10.1016/S0022-328X(00)00145-5

The tmeda ligand in the complexes, PdAr(N₃)(tmeda) is easily replaced by addition of tertiary phosphine or chelated phosphine to give the corresponding palladium(II) azido complexes with the phosphines ligand, PdAr(N₃)L₂ (1: Ar=Ph, L=PMe₃; 2: Ar=Ph, L=PEt₃; 3: Ar=tolyl, L=PMe₃; 4: Ar=naphthyl, L=PMe₃; 5: L₂=dppe). Complex 3 was characterized by X-ray crystallography. Complexes 1-2 react with CO (1 atm) to afford Pd(II) isocyanates, PdPh(NCO)L₂ (6, L=PMe₃; 7: L=PEt₃), in 98 and 76% yields, respectively. In contrast, the reaction of trans-PdMe(N₃)(PMe₃)₂ with CO gives acetylpalladium isocyanate, trans-Pd(COMe)(NCO)(PMe₃)₂ (8) in 96% yield, which is characterized by X-ray crystallography. Reactions of 1 with an equal amount of tert-butyl and cyclohexyl isocyanides cause 1,3-dipolar addition of the isocyanides to the azido ligand, to give the complexes, trans-PdPh[CN₄(R)](PMe₃)₂ (R=C(CH₃)₃, 9; C₆H₁₁, 10) with a five-membered heterocyclic ring (C-coordinated tetrazolato group). However, similar reactions of 1 and 3 with 2,6-dimethylphenyl isocyanide result in the unusual formation of Pd(II) complexes containing carbodiimido ligand, trans-(p-Y-C₆H₄)Pd(NCN-2,6-Me₂C ₆H₃)(PMe₃)₂ (Y=H, 11; Y=Me, 12) in 51 and 94% yields, respectively. Reactions of 1 with protonating agents such as benzenthiol and phenylacetylene are also described.

Full text of DOI:10.1016/S0022-328X(00)00145-5

www.elsevier.nl/locate/jorganchem
Journal of Organometallic Chemistry 603 (2000) 152–160
Synthesis and properties of arylpalladium(II) azido complexes
PdAr(N3)(PR3)2. Nucleophilic reactions of the azido ligand with
CO and with isocyanides to afford Pd(II) isocyanate, C-tetrazolate
and carbodiimide complexes
Yong-Joo Kim a,*,1, Yong-Su Kwak a, Soon-W. Lee b
a Department of Chemistry, Kangnung National Uni6ersity, Kangnung 210-702, South Korea
b Department of Chemistry, Sung Kyun Kwan Uni6ersity, Suwon 440-746, South Korea
Received 13 December 1999; received in revised form 7 February 2000; accepted 25 February 2000
Abstract
The tmeda ligand in the complexes, PdAr(N3)(tmeda) is easily replaced by addition of tertiary phosphine or chelated phosphine
to give the corresponding palladium(II) azido complexes with the phosphines ligand, PdAr(N3)L2 (1: Ar=Ph, L=PMe3; 2:
Ar=Ph, L=PEt3; 3: Ar=tolyl, L=PMe3; 4: Ar=naphthyl, L=PMe3; 5: L2=dppe). Complex 3 was characterized by X-ray
crystallography. Complexes 1–2 react with CO (1 atm) to afford Pd(II) isocyanates, PdPh(NCO)L2 (6, L=PMe3; 7: L=PEt3),
in 98 and 76% yields, respectively. In contrast, the reaction of trans-PdMe(N3)(PMe3)2 with CO gives acetylpalladium isocyanate,
trans-Pd(COMe)(NCO)(PMe3)2 (8) in 96% yield, which is characterized by X-ray crystallography. Reactions of 1 with an equal
amount of tert-butyl and cyclohexyl isocyanides cause 1,3-dipolar addition of the isocyanides to the azido ligand, to give the
complexes, trans-PdPh[CN4(R)](PMe3)2 (R=C(CH3)3, 9; C6H11, 10) with a five-membered heterocyclic ring (C-coordinated
tetrazolato group). However, similar reactions of 1 and 3 with 2,6-dimethylphenyl isocyanide result in the unusual formation of
Pd(II) complexes containing carbodiimido ligand, trans-(p-Y-C6H4)Pd(NCN-2,6-Me2C6H3)(PMe3)2 (Y=H, 11; Y=Me, 12) in 51
and 94% yields, respectively. Reactions of 1 with protonating agents such as benzenthiol and phenylacetylene are also described.
© 2000 Elsevier Science S.A. All rights reserved.
Keywords: Palladium; Azido; Isocyanate; Carbodiimide; Tetrazolato
compounds exhibit poorer chemical properties [2]. Sev-
eral Group 10 metal azido complexes with chelating or
tertiary phosphine and amine ligands were studied from
the viewpoints of the structural and magnetic properties
and reactions such as formation of metal nitrides spe-
cies or cluster compounds [3–7]. Recently, we also
reported synthesis and reactions of palladium(II) and
platinum(II) azido complexes containing chelating di-
amines or bisphosphines and monodentate tertiary
phosphines [8]. Among these studies of Group 10 metal
azido complexes, those of chemical reactions on the
metal azido complexes having alkyl or aryl ligand are
scarce [5,8]. The organometallic complexes with the
azido ligand possess potential utility as a precursor of
organotransition metal amide complex or organic
amines since the use of a suitable reducing agent would
cause the hydrogenation of the coordinated azido
1. Introduction
The azido (N−3 ) group coordinated to transition
metals has been intensively studied for many years, as
one of the important pseudo-halogeno ligands includ-
ing CN, SCN, and NCS [1]. The azido group can be
easily introduced into transition metal complexes by
metathesis reaction of NaN3 with halogeno complexes
of the transition metals. The azido ligand bonded to
transition metals undergo thermally or photo induced
cycloaddition or nitrene compounds formation,
whereas halogeno or other pseudo-halogeno ligands
* Corresponding author. Tel.: +82-391-6471183.
E-mail address: yjkim@knusun.kangnung.ac.kr (Y.-J. Kim)
1 Present address: Department of Chemistry, University of
Rochester, Rochester, NY 14627-0216, USA.
0022-328X/00/$ - see front matter © 2000 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(00)00145-5

Y.-J. Kim et al. / Journal of Organometallic Chemistry 603 (2000) 152–160
153
group, which can be extended to transformation of
organic azides to amines catalyzed by Group 10 metal
complexes.
As an extension of our recent work on the methylpal-
ladium(II) and platinum(II) azido complexes, herein we
report the preparation of arylpalladium(II) azido com-
plexes and their chemical properties toward CO and
isocyanides.
summarized in Tables 1–3, respectively. IR spectra
show a strong absorption band due to asymmetric
stretching vibrations w(N3) in the range 2028–2037
cm−1
.
(1)
2. Results and discussion
2.1. Preparation of arylpalladium(II) azido complexes
It is well known that tmeda (N,N,N%,N%-tetra-
methylethylenediamine) or COD (1,5-cyclooctadiene)
ligand coordinated to late transition metal is labile and
easily replaced by other P-donor ligands [9–11]. Re-
cently we reported the formation of methylpalla-
dium(II) and -platinum(II) azido complexes containing
tmeda or COD which is easily replaced with various
tertiary or chelating phosphines to give the correspond-
ing phosphine complexes with the azido ligand [8a,b].
In this work we applied similar ligand exchange reac-
Colorless crystals of 3 were obtained from an ether
solution at −30°C and analyzed by X-ray crystallogra-
phy. The molecule of 3 depicted in Fig. 1 contains a
4-methylphenyl, two PMe3 at mutually trans positions,
and one azido ligand around the square-planar Pd
center. The plane of the tolyl group lies almost perpen-
dicular to the coordination plane. The PdꢀN1 bond
tions
of
PdAr(N3)(tmeda)
(Ar=phenyl,
4-
,
length (2.114(3) A) is close to that of trans-
methylphenyl, naphthyl) with PMe3, PEt3, and
chelating phosphine as shown in Eq. (1). These reac-
tions provide a convenient synthetic method for various
new arylpalladium(II) azido complexes. The complexes
1–5 are isolated in 78–91% yields as colorless or pale-
yellow crystalline solids, which are thermally stable in
the solid state and in solution. The complexes were
characterized by IR, NMR (1H and 13C{1H}) spectra
,
PdMe(N3)(PMe3)2 (2.132(9) A) [8b], and is slightly
longer than that of (tmeda)Pd(N3)(C6H4-p-Me)
,
,
(2.017(9) A) [8a], [(C6H5CH2)3P]2Pd(N3)2 (2.045(6) A)
[12], and Pd2(N3)2− (2.004(5) A) [13], implying a larger
,
trans influence of phenyl ligand than azido group. The
bond angle N1ꢀN2ꢀN3 (176.3 (4)°) belongs to the
range of previously reported coordinated azide (173–
1
,
and elemental analyses. Analytical and IR data, H-,
180°) [2c]. A longer N1ꢀN2 (1.176 (4) A) distance than
13C{1H}-, and 31P{1H}-NMR data of the complexes are
the N2ꢀN3 (1.152 (4) A) distance indicates contribution
,
Table 1
Color, yield, analytical and IR results for complexes 1–13
b
Complex
Color
Yield (%)
Analyses a
C (%)
IR (cm−1
)
H (%)
N (%)
1
2
3
4
5
6
7
8
Pale yellow
Colorless
Colorless
Pale yellow
Pale yellow
Colorless
Pale yellow
Colorless
91
78
86
78
80
98
77
96
37.97 (38.16)
46.63 (46.81)
39.67 (39.86)
44.96 (44.93)
61.06 (61.60)
41.25 (41.34)
49.34 (49.41)
31.04 (31.46)
6.29 (6.14)
7.50 (7.64)
6.43 (6.43)
5.88 (5.89)
4.75 (4.68)
5.78 (6.14)
7.62 (7.64)
6.05 (6.16)
10.80 (11.13)
8.91 (9.10)
10.75 (10.73)
9.72 (9.82)
6.57 (6.73)
3.67 (3.71)
3.03 (3.03)
3.94 (4.08)
2032 n(N3)
2028 n(N3)
2035 n(N3)
2037 n(N3)
2028 n(N3)
2180 n(NCO)
2180 n(NCO)
2176 n(NCO)
1642 n(CO)
9
Colorless
White
Colorless
White
78
51
51
94
71
44.01 (44.31)
45.55 (46.87)
52.48 (52.46)
53.34 (53.40)
49.18 (48.60)
6.91 (7.00)
7.18 (7.04)
6.64 (6.71)
6.79 (6.92)
6.56 (6.34)
11.91 (12.16)
9.94 (11.51)
5.72 (5.83)
5.62 (5.66)
6.90 (7.21)
10
11
12
13
2127 n(NCN)
2149 n(NCN)
White
a Calculated values are given in parentheses.
b KBr disks.

154
Y.-J. Kim et al. / Journal of Organometallic Chemistry 603 (2000) 152–160
Table 2
1H-NMR data for complexes 1–13 a
b
Complex
PR3
Others c
Scheme 1.
1
2
1.14 (t, 18H,
4 Hz, PMe3)
1.09 (q, 18H, 8
Hz, P(CH2CH3)3) (d, 2H)
1.51 (m, 12H,
6.82 (t, 1H), 6.93 (t, 2H), 7.12
(d, 2H)
6.85 (t, 1H), 6.97 (t, 2H), 7.19
of structure (A) rather than the alternative resonance
structure shown in Scheme 1.
2.2. Reactions of phenyl(or methyl)palladium(II) azido
complexes with CO
P(CH2CH3)3)
3
4
1.18 (t, 18H,
3 Hz, PMe3)
1.08 (t, 18H,
3 Hz, PMe3)
2.21 (s, 3H, ꢀCH3), 6.83 (d, 2H),
7.03 (d, 2H)
7.14–7.19 (m, 1H), 7.36–7.45
(m, 4H)
7.66–7.71 (m, 1H), 8.39–8.42
(m, 1H)
Reactions of 1 and 2 with CO (1 atm) at room tem-
perature (r.t.) in THF, smoothly proceed to give iso-
cyanato complexes trans-PdPh(NCO)L2 (L=PMe3, 6;
PEt3, 7) in 98 and 76% yields, respectively, as shown in
Eq. (2).
5
2.18 (m, 2H,
PꢀCH2)
6.76–6.87 (m, 3H), 7.09–7.15 (2H)
2.46 (m, 2H,
PꢀCH2)
1.16 (t, 18H,
4 Hz, PMe3)
1.01 (q, 18H, 8
7.28–7.47 (m, 17H), 7.83–7.90
(m, 3H)
6.87 (t, 1H), 6.99 (t, 2H), 7.20
(d, 2H)
(2)
6
7
6.83 (t, 1H), 6.95 (t, 2H), 7.20
Hz, P(CH2CH3)3) (d, 2H)
1.48 (m, 12H,
PCH2)
The reaction was monitored by the IR spectra of the re-
action mixture, which shows a decrease in the intensity
of the asymmetric stretching band of the N3 group at ca.
2030 cm−1, and growth of a new band at 2180 cm−1 of
the product. The reactions occurred cleanly and gave no
other by products such as benzoyl isocyanato complex,
PhC(ꢁO)Pd(NCO)L2 or benzoyl azido complex,
PhC(ꢁO)Pd(N3)L2. Complexes 6 and 7 are obtained as
colorless crystals and characterized by IR, NMR (1H-,
13C{1H}-, and 31P{1H}-), and elemental analyses (Tables
1–3). A weak 13C-NMR signal at 128 ppm of 6 is as-
signed to the quaternary carbon of NꢁCꢁO, indicating a
conversion of the azido to the isocyanate ligand.
The reaction of trans-PdMe(N3)(PMe3)2 [8b] with CO
(1 atm) gives the acetylpalladium isocyanato complex
trans-Pd(COMe)(NCO)(PMe3)2 (8) in 96% yield as
shown in Eq. (3).
8
1.38 (t, 18H,
4 Hz, PMe3)
0.96 (t, 18H,
3 Hz, PMe3)
0.97 (t, 18H,
4 Hz, PMe3)
2.30 (s, 3H, ꢀCOCH3)
9
1.84 (s, C(CH3)3), 6.90 (t, 1H),
7.02 (br, 2H), 7.34 (br, 2H)
1.25–1.48 (m, 4H, ꢀC6H11),
10
1.79–2.16 (m, 7H, ꢀC6H11
)
4.55 (m, 1H, ꢀC6H11), 6.92
(t, 1H), 7.05 (t, 2H), 7.34 (br, 2H)
2.39 (s, 6H, (CH3)2ꢀC6H3), 6.66
(t, 1H), 6.88–7.01 (m, 5H), 7.22
(d, 2H)
11
12
1.16 (t, 18H,
4 Hz, PMe3)
1.16 (t, 18H,
4 Hz, PMe3)
2.21 (s, 3H, C6H4-p-CH3), 2.38
(s, 6H, (CH3)2ꢀC6H3)
6.65 (t, 1H), 6.83 (d, 2H), 6.91
(d, 2H), 7.06 (d, 2H)
13
1.12 (t, 18H,
3 Hz, PMe3)
6.89 (t, 1H), 6.92 (t, 1H), 7.04
(m, 4H), 7.37 (d, 2H), 7.62 (d, 2H)
a At 25°C in CDCl3. 500 MHz for 1, 2, 5, 6, 8–10, and 13. 300
MHz for 3, 4, 7, 11, and 12.
(3)
b Apparent triplet or quintet due to virtual coupling unless other-
wise stated. Splitting, due to the virtual coupling, is in parentheses.
c Aryl hydrogens unless otherwise stated.
The reaction results in both CO insertions into the
Pdꢀmethyl bond to give an acyl group and conversion
of the azido ligand to an isocyanato group coordinated
to Pd center. The IR spectrum of 8 shows a strong ab-
sorption bands at 1642 cm−1 due to carbonyl in the acyl
group and at 2176 cm−1 due to the isocyanato group.
The former band falls within the value (1610–1675
cm−1) of acyl group coordinated Pd center [14]. The
1H-NMR signal at 2.30 ppm of 8 is attributed to the
CH3 hydrogen of the acetyl ligand. The 13C{1H}-NMR
spectrum contains a signal at 228.9 and 128.5 ppm,
which are assigned to the carbonyl carbon of the acetyl
ligand and the quaternary carbon of the NꢁCꢁO ligand,
respectively. All these spectroscopic data of 8 are well
consistent with the proposed structure.
Crystals of 8 were analyzed by X-ray crystallography.
The molecular structures of 8 with the atomic number-
ing scheme are shown in Fig. 2. The molecule of 8 has a
square planar coordination around a Pd center contain-
ing two PMe3 ligands, an acetyl, and an isocyanato lig-
and. The isocyanato (NꢁCꢁO) and acetyl ligands are at
mutually trans positions. The acetyl plane is essentially
perpendicular to the equatorial plane with a dihedral
,
angle of 86.0(2)°. The PdꢀN bond distance of 2.119(5) A
,
is close to that found in 3 (2.114(3) A) and that of trans-
,
PdPh(NHPh)(PMe3)2 (2.116(13) A) [15]. The CO (1.187
A) bond distance in the NCO ligand is longer than the
,
,
CN (1.127 A) distance similarly to those found in other

Y.-J. Kim et al. / Journal of Organometallic Chemistry 603 (2000) 152–160
155
Table 3
13C{1H}- and 31P{1H}-NMR data for complexes 1–13
a
13C{1H}
31P{1H} b
c
PR3
Others d
1
2
3
13.17 (t, 14 Hz, PMe3)
7.8 (s, P(CH2CH3)3) 13.9 (t, 13 Hz, PCH2)
13.2 (t, 14 Hz, PMe3)
122.9 (s), 127.8 (s), 135.9 (s), 159.5 (t)
−15.7
14.6
−15.9
122.3 (s), 127.5 (s), 136.0 (t, J=4 Hz), 150.7 (s)
20.7 (s, CH3), 128.6 (s), 131.9 (s), 135.5 (t, 5 Hz), 145.2
(t, J=8 Hz)
4
5
13.4 (t, 14 Hz, PMe3)
122.8, 124.4, 125.0, 125.4, 128.2, 132.3, 132.6 (t, J=3 Hz), 134.0,
139.0, 153.1 (t, J=9 Hz) (naphthyl)
127.8, 127.9, 128.7, 128.8, 129.0, 129.1, 129.3, 129.7, 130.8, 131.0,
131.6, 131.2, 131.2, 132.9, 133.0, 133.2, 133.3, 135.1, 135.2, 135.1,
135.2
−14.5
22.5 (dd, ꢀCH2) J=11, 21 Hz 29.9 (dd,
ꢀCH2) J=22, 31 Hz
32.7, 50.4,
J=28 Hz
6
13.4 (t, 15 Hz, PMe3)
7.82 (s, P(CH2CH3)3) 14.1 (t, 13 Hz, PCH2)
14.1 (t, 14 Hz, PMe3)
122.8 (s), 127.6 (s), 128.3 (s, NCO), 136.1 (t, J=5 Hz), 150.4 (s)
122.2, 127.4 (Ph), 136.4 (t, J=4 Hz), 150.3 (Ph)
42.0 (t, J=18 Hz, ꢀCOCH3), 128.5 (s, NCO), 228.8 (s, ꢀCOCH3)
31.3 (s, C(CH3)3), 57.2 (s, C(CH3)3), 122.7 (s), 126.9 (s), 127.3 (s),
137.9 (s), 138.4 (s), 160.4 (t, J=10 Hz), 168.4 (t, 16 Hz, CN4
(t-Bu))
−16.4
14.6
−18.7
−18.1
7 e
8
9
14.5 (t, 15 Hz, PMe3)
10
14.5 (t, 15 Hz, PMe3)
22.6 (s, C6H11), 25.8 (s, C6H11), 34.0 (s, C6H11), 58.8 (s, C6H11),
122.8 (s), 126.9 (s), 127.4 (s), 137.1 (s), 138.3 (s), 161.3 (t, J=10
−17.0
Hz), 171.3 (t, J=17 Hz, CN4(C6H11
19.4 (s, (CH3)2ꢀC6H3), 119.1 (s), 122.7 (s), 127.6 (s), 127.7 (s), 130.9 −16.3
(s), 136.2 (t, J=5 Hz), 145.2 (s), 150.9 (bs)
19.5 (s, C6H4-p-Me), 20.7 (s, (CH3)2ꢀC6H3), 119.1, 127.7, 128.6,
130.9, 131.8), 131.9 (s), 135.9 (t, J=5 Hz), 145.3 (s)
120.9, 122.6), 127.4, 127.5, 132.5 (s), 136.6 (t, J=5 Hz), 149.9 (s),
159.0 (t, J=8 Hz)
)
11 e 13.5 (t, 14 Hz, PMe3)
12 e 13.6 (t, 14 Hz, PMe3)
−16.4
13
13.9 (t, 15 Hz, PMe3)
−16.4
a At 25°C in CDCl3. 125 MHz for 1, 2, 5, 6, 8–10, and 13. 75 MHz for 3, 4, 7, 11, and 12.
b At 25°C in CDCl3. 200 MHz for 1, 2, 5, 6, 8–10, and 13. 120 MHz for 3, 4, 7, 11, and 12.
c Apparent triplet or quintet due to virtual coupling except 5. Splitting due to the virtual coupling are in parentheses except 5.
d Aromatic carbons unless otherwise stated.
e NCN and NCO carbon signals are weak and not observed.
transition metal isocyanates [1]. The CN bond length is
2.3. Reactions of 1 with isocyanides
,
nearer to that of reported the CꢂN (1.16 A) [16] rather
,
than the CꢀN single bond distance (1.47 A) (see Table
We have further developed small-molecule insertion
reactions using isocyanides, which are isoelectronic with
4 for a full list of bond lengths and angles).
It is assumed that the CO coordinates in the central
metal atom as the initial step and is followed by the
interaction between azido group and the coordinated
CO and then finally NꢀN2 bond cleaves to give the
isocyanato group. Another possibility of the prior dis-
sociation of azido anion or phosphine ligand has been
considered. Earlier work by Beck and co-workers
demonstrated that several transition metal azido com-
plexes react with CO to give corresponding isocyanato
complexes [2a,17]. They also suggested the mechanism
by the basis of kinetic experiments. Several additional
examples of the complexes by other researcher also
have been reported [18,19].
Different products in the preceding two reactions
(Eqs. (2) and (3)) show that CO is inserted into the
Pdꢀmethyl bond more easily than the Pdꢀphenyl bond
under mild conditions and vice versa, indicate that the
MꢀC (sp2) bond is more kinetically stable than the
MꢀC(sp3) bond toward CO.
Fig. 1. An ORTEP drawing of 3 showing the atom-labeling scheme and
50% probability thermal ellipsoids.

156
Y.-J. Kim et al. / Journal of Organometallic Chemistry 603 (2000) 152–160
[CN4(R)](PMe3)2 (R=t-Bu, (9); R=cyclohexyl, (10) in
51 and 78% yield as shown in Eq. (4). The complexes
were obtained as colorless crystals, which are stable in
solid state and in solution, and characterized by IR,
NMR, and elemental analyses. The product formation
was easily confirmed by disappearance of w(N3) absorp-
tion band. Other insertion products such as imino acyl
complex, trans-PhC(ꢁNR)PdN3(PMe3)2 by isocyanide
insertion into the Pdꢀphenyl bond were not observed.
The cycloaddition reactions of late transition metal
complexes using isocyanides to give the complexes with
C-coordinated tetrazolato ring, have been originally
studied by Beck and co-workers [20], whereas similar
reactions of azido complexes of Pd(II) [19], Co(II) [21],
Cu(I), Ag(I), and Au(I) [22] having terminal or bridging
azido ligands with CS2 or CF3CN to give the complexes
with N-coordinated tetrazolato ring have also been
studied by several research groups.
Fig. 2. An ORTEP drawing of 8 showing the atom-labeling scheme and
50% probability thermal ellipsoids.
Table 4
,
Selected bond distances (A) and bond angles (°) for 3, 8, and 11
3
8
11
Similar reactions of 1 and 3 with 2,6-dimethylphenyl
isocyanide under similar conditions unusually afford
the palladium(II) complexes containing carbodiimido
Bond distances
Pd1ꢀC7
Pd1ꢀN1
Pd1ꢀP1
Pd1ꢀP2
N1ꢀN2
2.010(3)
2.114(3)
2.3106(8)
2.3252(8)
1.176(4)
1.152(4)
1.963(5)
2.119(5)
2.324(1)
2.318(1)
2.014(3)
2.087(3)
2.3111(9)
2.3231(8)
ligand,
trans-(p-Y-C6H4)Pd(NCN-2,6-Me2C6H3)-
(PMe3)2 (Y=H, (11); Y=Me, (12)) in 51 and 94%
yields, respectively, as shown in Eq. (5).
N2ꢀN3
(4)
O1ꢀC7
O2ꢀC9
N1ꢀC9
C7ꢀC8
1.200(6)
1.187(6)
1.127(7)
1.499(7)
N1ꢀC13
N2ꢀC13
N2ꢀC14
1.172(4)
1.270(4)
1.408(4)
Bond angles
C7ꢀPd1ꢀN1
P1ꢀPd1ꢀP2
C7ꢀPd1ꢀP1
N1ꢀPd1ꢀP1
C7ꢀPd1ꢀP2
N1ꢀPd1ꢀP2
N2ꢀN1ꢀPd1
N3ꢀN2ꢀN1
C9ꢀN1ꢀPd1
O1ꢀC7ꢀC8
O1ꢀC7ꢀPd1
C8ꢀC7ꢀPd1
N1ꢀC9ꢀO2
N1ꢀC13ꢀN2
178.44(12)
174.77(3)
87.58(8)
93.37(8)
87.75(8)
91.24(8)
132.4(2)
176.3(4)
175.8(2)
170.27(5)
89.0(1)
91.3(1)
89.9(1)
90.5(2)
175.36(11)
169.62(3)
85.28(9)
92.99(8)
88.88(9)
93.45(8)
(5)
166.9(5)
119.7(5)
125.4(4)
115.0(4)
178.8(7)
The carbodiimido complexes 11 and 12 exhibit new
strong w(NCN) IR bands at 2126 and 2149 cm−1. Their
completion can be monitored easily by the disappear-
ance of the asymmetric stretching band of the N3
group, at ca. 2030 cm−1 in the IR spectrum of the
reaction mixture. The reactions occurred cleanly and
gave no other by products such as the tetrazolato
172.8(3)
CO. Previously we observed 1,3-dipolar addition of
isocyanides to the azido moiety of methylpalladium(II)
and platinum(II) azido complexes giving five-membered
heterocycles [8b]. In this work we have carried out
similar additional reactions using various isocyanides.
Reactions of an equimolar amount of tert-butyl iso-
cyanide and cyclohexyl isocyanide with 1 in THF at r.t.
give the complexes with a five-membered heterocyclic
ring (C-coordinated tetrazolato ring), trans-PdPh-
complex,
trans-(p-Y-C6H4)Pd[CN4(2,6-Me2C6H3)]-
(PMe3)2 and the iminoacyl complex, trans-(p-Y-
C6H4)C(ꢁNR)PdN3(PMe3)2. To our knowledge, com-
plexes 11 and 12 are the first isolated examples of
Group 8–10 transition metal carbodiimido complexes.
Fig. 3 shows the molecular structure of 11, which has
a slightly distorted square-planar coordination, con-
taining two PMe3, phenyl, and NCN-2,6-Me2C6H3
group. The carbodiimido (NꢁCꢁN) group with an ap-

Y.-J. Kim et al. / Journal of Organometallic Chemistry 603 (2000) 152–160
157
proximate linear angle (N1ꢀC13ꢀN2, 172.8°) is out of
benzenethiol and phenylacetylene with 1. The reaction
of 1 with an equimolar amount of benzenethiol at r.t.,
produced a thiolato complex trans-PdPh(SPh)(PMe3)2
(13) in 71% yield, as a white solid, as shown in Eq. (6).
,
the equatorial plane. The PdꢀN (2.087 A) distance falls
in the range of PdꢀN distances as the case previously
discussed metal azides and other comparable bond
lengths are not available, because there have been no
related reports. However, interestingly, the N1ꢀC13
,
(1.172 A) bond distance is very close to the general
,
CꢂN (1.16 A) and is shorter than that of N2ꢀC13
,
,
(1.270 A). This feature is similar to the NC (1.139 A)
and CN (1.314 A) bond lengths of (CO)5CrNCN-
,
(6)
(C2H5)2 [23], prepared from the reaction of
[(CO)5CrCN(C2H5)2][BF4] with [N(C4H9)]N3. Beck and
co-workers [20d] reported the preparation of an Au
carbodiimide complex from the thermolysis of
AsPh4[Au(CN4CH2C6H5)4]. Polymerization of carbodi-
imide has been reported recently by the use of transi-
tion metal complexes as the catalyst [24]. The
carbodiimide complexes are considered as an important
intermediate in the polymerization.
The phenyl- and methylpalladium azido complexes
with a trans structure, react with CO and CNR to
afford various kinds of products as described previ-
ously. The reactions probably involves initial nucleo-
philic attack of the azido ligand to CO or CNR
molecules coordinated to the Pd center to form a new
CꢀN bond. Ensuing elimination of N2 molecule or
cyclization occurs to give isocyanate complex or C-te-
trazolato complex. Direct formation of the carbo-
diimide complex is a new reaction and seems to involve
initial formation of the C-coordinated tetrazolato com-
plex, which undergoes elimination of an N2 molecule to
give the product. The carbodiimide formation may be
explained by the electronic or steric factor of the coor-
dinated ligands around the Pd center as well as attack-
ing isocyanide.
The isolated complex is soluble in ether and hexane.
However, the same reaction of an excess amount of
benzenethiol gave 13 (62%) as a major product and a
bisthiolato complex, trans-Pd(SPh)2(PMe3)2 (12%) as a
minor product, which was identified by comparison of
the NMR data with that of the authentic complex. A
similar reaction of 1 with an excess amount of phenyl-
acetylene, did not occur and resulted in stoichiometric
recovery of the starting complex. Previously we have
reported that reaction of trans-PdMe(N3)(PMe3)2 with
an equimolar or excess amount of phenylacetylene at
r.t. in THF afforded
a
bisacetylide complex,
Pd(CꢂCPh)2(PMe3)2 [8b]. These results indicate that the
Pdꢀphenyl bond is more stable than the Pdꢀmethyl
bond toward protonating agents.
In summary, we have prepared new arylpalladium(II)
azido complexes with a trans structure and the reaction
with CO, CNR and HSPh to convert the azido ligand
to NꢁCꢁO, CN4R, and SPh ligands, respectively. The
products of the two former reactions suggest nucleo-
philic attack of the azido ligand bonded to the metal
center toward electrophilic carbons of CO and CNR or
protic hydrogen of HSPh. The functionality of the
azido ligand bonded to the metal center having aryl or
alkyl ligand seems to be of interest as the reaction
intermediate of the corresponding synthetic organic
reactions catalyzed by the Group 10 metals.
2.4. Other reactions of 1
In order to get further insight on chemical properties
of the azido complexes we have examined reactions of
3. Experimental
All the manipulations of air-sensitive compounds
were performed under N2 or argon atmosphere with use
of standard Schlenk technique. Solvents were distilled
from Na-benzophenone. PdAr(N3)(tmeda) (Ar=C6H5,
C6H4-p-Me, and 1-naphthyl) [8a] and trans-
PdMe(N3)(PMe3)2 [8b] were prepared by the literature
method. Elemental analyses were carried out by the
analytical laboratory at Basic Science Institute of Ko-
rea. IR spectra were recorded on a Hitachi 270–30 and
Perkin–Elmer BX spectrophotometer. NMR (1H,
13C{1H} and 31P{1H}) spectra were obtained on
Bruker-300 and 500 MHz and on JEOL Lamda 300
MHz spectrometers. Chemical shifts were referenced to
an internal Me4Si and to an external 85% H3PO4.
Fig. 3. An ORTEP drawing of 11 showing the atom-labeling scheme
and 50% probability thermal ellipsoids.

158
Y.-J. Kim et al. / Journal of Organometallic Chemistry 603 (2000) 152–160
3.1. Preparation of arylpalladium(II) azido complexes
(1–5)
gen. After stirring for 3 h the reaction mixture was fully
evaporated and then the resulting solid was washed
with hexane (3×2 ml). Recrystallization from
CH2Cl2–hexane gave colorless crystals of trans-
PdPh(NꢁCꢁNꢀR)(PMe3)2 (R=2,6-Me2C6H3) (11, 0.136
g, 51%). Reaction of 3 with 2,6-dimethylphenyl iso-
cyanide proceeded analogously to give trans-Pd(C6H4-
p-Me)(NꢁCꢁNꢀR)(PMe3)2 (R=2,6-Me2C6H3) (12,
0.449 g, 94%).
To a stirred THF (30 ml) solution containing
PdPh(N3)(tmeda) (0.424 g, 1.24 mmol) was slowly
added PMe3 (0.282 ml, 2.73 mmol) at r.t. by a syringe.
After stirring for 1 h, the pale yellow solution was
evaporated and the resulting solid was washed with
hexane. Recrystallization from THF–hexane gave pale
yellow crystals of 1 (0.424 g, 91%). Complexes 2–5
were prepared analogously.
3.6. Reactions of 1 with HSPh and diphenylacetylene
3.2. Reactions of 1 and 2 with CO
To a THF (4 ml) solution of 1 (0.222 g, 0.59 mmol)
was added benzenethiol (0.065 g, 0.59 mmol) at r.t. The
initial colorless solution instantly turned yellow. After
stirring for 2 h the yellow solution was fully evaporated
to give a yellowish residue. Addition of hexane dis-
solved the residue. Cooling of the filtered solution for
several hours at −30°C produced a white precipitate,
which was collected by filtration to give trans-PdPh(-
SPh)(PMe3)2 (13, 0.188 g, 71%) as a white solid. trans-
Pd(SPh)2(PMe3)2 was obtained from a similar reaction
in low yield (12%), or reaction of trans-PdMe2(PMe3)2
with excess benzenethiol and identified by comparison
of the spectroscopic data with the authentic complexes.
Similar reaction with excess amount of pheny-
lacetylene resulted in recovery of the starting material.
Complex 1 (0.300 g, 0.80 mmol) was dissolved in
THF (3 ml) at r.t. After evacuation of the system, CO
(1 atm) was introduced and the initial solution slowly
turned colorless. After stirring for 24 h the solvent was
evaporated under reduced pressure to give a white
solid. Recrystallization from THF–hexane gave color-
less crystals of 6 (0.295 g, 98%).
Reaction of 2 with CO proceeded analogously, to
give 7 as pale yellow crystals (77%).
3.3. Reaction of trans-PdMe(N3)(PMe3)2 with CO
trans-PdMe(N3)(PMe3)2 (0.327 g, 1.035 mmol) was
dissolved in THF (4 ml) at r.t. After evacuation of the
system, CO (1 atm) was introduced and the initial
solution slowly turned colorless. After stirring for 48 h
the solvent was evaporated under reduced pressure to
give a white solid. Recrystallization from THF–hexane
gave colorless crystals of 8 (0.343 g, 96%).
3.7. X-ray structure determination
All X-ray data were collected using a Siemens P4
diffractometer equipped with a Mo X-ray tube and a
graphite crystal monochromator. The orientation ma-
trix and unit cell parameters were determined by least-
squares analyses of the setting angles of 51 reflections in
the range 10.0°B2qB25.0°. Intensity data were cor-
rected for Lorentz and polarization effects. Decay cor-
rections were also made. The intensity data were
empirically corrected with „-scan data. All calculations
were carried out using the SHELX-97 programs [25]. The
structure was solved by direct methods and refined by
full-matrix least-squares calculations of F2 values, ini-
tially with isotropic, and finally anisotropic temperature
factors for all non-hydrogen atoms. All hydrogen
atoms were located in the difference Fourier map and
refined isotropically.
3.4. Reaction of 1 and 4 with tert-butyl and cyclohexyl
isocyanides
To a THF (5 ml) solution containing 1 (0.267 g, 0.71
mmol) was added tert-butyl isocyanide (0.071 g, 0.85
mmol) at r.t. The initial yellow solution turned color-
less. After stirring for 4 h, the reaction mixture was
stored at −20°C for ca. 12 h and the resulting white
precipitate was washed with hexane (2×3 ml). Recrys-
tallization from THF–hexane gave colorless crystals of
trans-PdPh[CN4(R)](PMe3)2 (R=C(CH3)3) (9, 0.253 g,
78%). Reaction of 1 with cyclohexyl isocyanide gave
trans-PdPh[CN4(R)](PMe3)2
analogously (51%).
(R=C6H11)
(10)
The crystal data, and details in structure refinement
of 3, 8, and 11 are summarized in Table 5.
3.5. Reactions of 1 and 3 with 2,6-dimethylphenyl
isocyanide
4. Supplementary material
To a CH2Cl2 (1 ml) solution containing 1 (0.211 g,
0.56 mmol) was added 2,6-dimethylphenyl isocyanide
(0.073 g, 0.56 mmol) at r.t. The initial pale yellow
solution instantly turned yellow with evolution of nitro-
Crystallographic data (excluding structural factors)
for the structure in the paper have been deposited with
the Cambridge Crystallographic Data Centre as supple-
mentary publication nos. CCDC 137699–137701.

Y.-J. Kim et al. / Journal of Organometallic Chemistry 603 (2000) 152–160
159
Table 5
Crystallographic data and refinement details for 3, 8, and 11
3
8
11
Chemical formula
Formula weight
Crystal system
Space group
C13H25N3P2Pd
391.70
Monoclinic
P21/c
C9H21NO2P2Pd
343.61
Orthorhombic
Pbca
C21H32N2P2Pd
480.83
Monoclinic
P21/c
,
a (A)
13.021(1)
6.8472(7)
20.260(1)
98.315(9)
1787.3(3)
4
1.209
800
1.456
10.152(1)
13.547(2)
22.144(2)
14.624(3)
8.769(2)
18.890(4)
108.75(1)
2293.6(7)
4
0.956
992
1.392
,
b (A)
,
c (A)
i (°)
V (A )
3
,
3045.6(7)
8
1.413
1392
1.499
Z
v (mm−1
F(000)
)
Dcalc (g cm−3
)
Crystal size (mm)
Scan range
0.72×0.14×0.12
3.5°B2qB50°
3279
3132
2709
172
1.027
0.377, −0.490
0.3283, 0.3679
0.0282 (0.0698)
0.80×0.60×0.12
3.5°B2qB50°
2619
2617
2206
137
1.025
0.698, −1.258
0.2209, 0.2820
0.0430 (0.1147)
0.52×0.36×0.10
3.5°B2qB50°
4474
4037
3471
236
1.039
0.361, −0.344
0.4720, 0.5227
0.0305 (0.0753)
Measured reflections
Unique reflections
Used reflections [I]2|(I)]
No. of parameters
Goodness-of-fit on F2
−3
,
Max/min in Dz (e A
)
Tmin, Tmax
a
R (wR2
)
a wR2=S[w(Fo2−Fc2)2]/S[w(Fo2)2]1/2
.
[7] (a) A. Escuer, R. Vicente, M.S. El Fallah, X. Solans, M.
Font-Bardia, Inorg. Chim. Acta 247 (1996) 85. (b) J. Ribas, M.
Monfort, B.K. Ghosh, R. Cortes, X. Solans, M. Font-Bardia,
Inorg Chem. 35 (1996) 864 and references therein.
[8] (a) Y.-J. Kim, D.-H. Kim, S.-W. Song, T.-I. Son, Bull. Korean
Chem. Soc. 19 (1998) 125. (b) Y.-J. Kim, D.-H. Kim, J.-Y. Lee,
S.-W. Lee, J. Organomet. Chem. 538 (1997) 189. (c) Y.-J. Kim,
J.-Y. Lee, Bull. Korean Chem. Soc. 16 (1995) 558.
Copies of this information may be obtained 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).
[9] P.M. Maitlis, P. Espinet, M.J.H. Russel, in: G. Wilkinson,
F.G.A. Stone, E.W. Abel (Eds.), Comprehensive Organometallic
Chemistry, vol. 6, Pergamon, Oxford, 1982.
Acknowledgements
[10] H.C. Clark, L.E. Manzer, J. Organomet. Chem. 59 (1973) 411.
[11] W. de Graaf, J. Boersma, W.J.J. Smeets, A.L. Spek, G. van
Koten, Organometallics 8 (1989) 2907.
[12] B. Bendiksen, W.C. Riley, M.W. Babich, J.H. Nelson, R.A.
Jacobson, Inorg. Chim. Acta 57 (1982) 29.
This work was supported by the Basic Science Re-
search Institute Program (No. BSRI-98-3440), Korean
Ministry of Education.
[13] W.P. Fehlhammer, L.F. Dahl, J. Am. Chem. Soc. 94 (1972) 3377.
[14] G. Booth, J. Chatt, J. Chem. Soc. (A) (1966) 634.
[15] L.A. Villanueva, K.A. Abboud, J.M. Boncella, Organometallics
13 (1994) 3921.
References
[16] J.E. Huheey, E.A. Keitter, R.L. Keitter, Inorganic Chemistry,
fourth ed., Harper Collins, 1993, Appendix, Table E1.
[17] (a) W. Beck, W.P. Fehlhammer, P. Pollmann, H. Schachl, Chem.
Ber. 102 (1969) 1976. (b) W. Beck, M. Bauder, W.P. Fehlham-
mer, P.P. Pollmann, H. Schachl, Inorg. Nucl. Chem. Lett. 4
(1969) 143.
[1] G. Wilkison, R.D. Gillard, J.A. McCleverty, Comprehensive
Coordination Chemistry, vol. 2, Pergamon, Oxford, 1987, p. 225.
[2] For reviews: (a) W. Beck, J. Organomet. Chem. 383 (1990) 143.
(b) J. Strahle, Comments Inorg. Chem. 4 (1985) 295. (c) S.
Cenini, G. La Monica, Inorg. Chim. Acta 18 (1976) 279. (d) Z.
Dori, R.F. Ziolo, Chem. Rev. 73 (1973) 247.
[3] A. Becalska, R.J. Batchelor, F.W.B. Einstein, R.H. Hill, B.J.
Palmer, Inorg. Chem. 31 (1992) 3118.
[4] H. Klein, S. Haller, H. Ko¨nig, M. Dartiguenave, Y. Dartigue-
nave, M. Menu, J. Am. Chem. Soc. 113 (1993) 4673.
[5] G. Alibrandi, L. Monsu Scolaro, D. Minniti, R. Romeo, Inorg.
Chem. 29 (1990) 3467.
[18] W.O. Siegl, S.J. Lapporte, J.P. Collman, Inorg. Chem. 10 (1971)
2158.
[19] L. Busetto, A. Palazzi, R. Ros, Inorg. Chim. Acta 13 (1975) 233.
[20] (a) P. Kreutzer, Ch. Weis, H. Bock, J. Erbe, W. Beck, Chem. Ber.
116 (1983) 2691. (b) J. Erbe, W. Beck, Chem. Ber. 116 (1983)
3867. (b) P. Kreutzer, Ch. Weis, H. Boehme, T. Kemmerich, W.
Beck, C. Spencer, R. Mason, Z. Naturforsch. Teil B 27 (1972)
745. (d) W. Beck, K. Burger, W.P. Fehlhammer, Chem. Ber. 104
(1971) 1816. (e) W. Beck, W.P. Fehlhammer, H. Bock, M.
Bauder, Chem. Ber. 102 (1969) 3637.
[6] (a) J. Strahle, J. Organomet. Chem. 488 (1995) 15. (b) M. Breuer,
J. Strahle, Z. Anorg. Allg. Chem. 619 (1993) 1564. (c) M. Laupp,
J. Strahle, Angew. Chem. Int. Ed. Engl. 33 (1994) 207.

160
Y.-J. Kim et al. / Journal of Organometallic Chemistry 603 (2000) 152–160
[21] S. Kozima, I. Itano, N. Mihara, K. Sisido, T. Isida, J.
Organomet. Chem. 44 (1972) 117.
[22] (a) R.F. Ziolo, Z. Dori, J. Am. Chem. Soc. 90 (1968) 6560. (b)
R.F. Ziolo, J.A. Phich, Z. Dori, Inorg. Chem. 11 (1972) 626. (c)
A.P. Gaughan, K.S. Bowman, Z. Dori, Inorg. Chem. 11 (1972)
601.
Organomet. Chem. 149 (1978) C40. (b) U. Schubert, D. Neuge-
bauer, P. Fridrich, Acta Crystallogr. Sect. B 34 (1978) 2293.
[24] K. Shibayama, S.W. Seidel, B. Novak, Polymer Preprints, Divi-
sion of Polymer C 19960802 (US), The Division Program for the
Orlendo Meeting.
[25] G.M. Sheldrick, SHELX-97, University of Go¨ttingen, Germany,
1997.
[23] (a) E.O. Fisher, W. Leine, U. Schubert, D. Neugebauer, J.
.