Palladium(II) amido complexes with an unsymmetrical PNP′ pincer-type coordination and a new (E,E)-tetradentate diphosphinoazine coordination mode

Article abstract of DOI:10.1016/j.ica.2004.06.022

Cationic palladium(II) complexes [PdCl{PR₂CH ₂C(Bu^t)NNC(Bu^t)CH₂PR₂}] Cl (R=Prⁱ, c-C₆H₁₁, Bu^t) were synthesized. Their reactions with triethylamine gave complexes [PdCl{PR ₂CHC(Bu^t)NNC(Bu^t)CH₂PR ₂}], containing deprotonated diphosphinoazines in ene-hydrazone unsymmetrical pincer-like configuration which represent several of the still rare examples of Pd(II) amido bis(phosphine) complexes. A novel (E,E) tetradentate coordination mode of diphosphinoazines was also discovered. Cationic palladium(II) complexes [PdCl{PR₂CH₂C(Bu ^t)NNC(Bu^t)CH₂PR₂}]Cl, where R = isopropyl, cyclohexyl or tert-butyl, were synthesized by the reactions of the corresponding diphosphinoazines with bis(acetonitrile)palladium(II) dichloride. When bis(benzonitrile)palladium(II) dichloride was used instead, in the molar ratio of 2:1 to the diphosphinoazine, a new complex was isolated with the isopropyl ligand showing a previously unknown (E,E) tetradentate coordination mode. Crystal and molecular structure was determined by X-ray diffraction. The solid complex was a racemate of two axially chiral enantiomers and the chirality was preserved in solution. Reactions of the cationic complexes with triethylamine gave complexes [PdCl{PR₂CHC(Bu^t)NNC(Bu ^t)CH₂PR₂}], containing deprotonated diphosphinoazines in ene-hydrazone unsymmetrical pincer-like configuration. The complexes represent several of the still rare examples of Pd(II) amido bis(phosphine) complexes with a chlorine atom covalently bonded trans to the amide nitrogen.

Full text of DOI:10.1016/j.ica.2004.06.022

Inorganica Chimica Acta 357 (2004) 4165–4171
www.elsevier.com/locate/ica
Palladium(II) amido complexes with an unsymmetrical PNP0
pincer-type coordination and a new (E,E)-tetradentate
diphosphinoazine coordination mode
a
Jan Storch , Jan Cermak , Pavel Vojtısek , Ivana Cısarova
a,
b
c
*
ˇ
´
´
ˇ
´ ˇ
´
a
´
Institute of Chemical Process Fundamentals, AS CR, Rozvojova 135, Prague 6, Czech Republic
Department of Inorganic Chemistry, Faculty of Natural Sciences, Charles University, Hlavova 2030, CZ-12840 Prague, Czech Republic
b
c
Center of Molecular and Crystal Structures, Faculty of Natural Sciences, Charles University, Hlavova 2030, CZ-12840 Prague, Czech Republic
Received 9 February 2004; accepted 12 June 2004
Available online 29 July 2004
Abstract
Cationic palladium(II) complexes [PdCl{PR2CH2C(But)‚NN‚C(But)CH2PR2}]Cl, where R=isopropyl, cyclohexyl or tert-bu-
tyl, were synthesized by the reactions of the corresponding diphosphinoazines with bis(acetonitrile)palladium(II) dichloride. When
bis(benzonitrile)palladium(II) dichloride was used instead, in the molar ratio of 2:1 to the diphosphinoazine, a new complex was
isolated with the isopropyl ligand showing a previously unknown (E,E) tetradentate coordination mode. Crystal and molecular
structure was determined by X-ray diffraction. The solid complex was a racemate of two axially chiral enantiomers and the chirality
was preserved in solution. Reactions of the cationic complexes with triethylamine gave complexes [PdCl{PR2CH‚C(But)NN‚C-
(But)CH2PR2}], containing deprotonated diphosphinoazines in ene-hydrazone unsymmetrical pincer-like configuration. The com-
plexes represent several of the still rare examples of Pd(II) amido bis(phosphine) complexes with a chlorine atom covalently bonded
trans to the amide nitrogen.
ꢀ 2004 Elsevier B.V. All rights reserved.
Keywords: Axial chirality; Amido complexes; Palladium; Diphosphinoazine; P–N ligand
1. Introduction
electron pair. Coordination of diphosphinoazines in
(E,E) configuration has not been reported so far.
Diphosphinoazines derived from pinacolone azine
were introduced by Shaw and coworkers [1] as very flex-
ible and versatile polydentate phosphorus–nitrogen lig-
ands. They can coordinate in (Z,Z) configuration to
one [2–4] or two [5,6] transition metals. More frequently,
they chelate a metal in (E,Z) configuration with the two
phosphorus atoms either in cis- [7] or trans- [8] posi-
tions; a terdentate PNP0 coordination is found in the lat-
ter case with one of the nitrogens coordinated by an
There is, however, another coordination mode of
diphosphinoazines which seems to be a little overlooked.
In a so called ene-hydrazone coordination mode [5] (1),
the deprotonated diphosphinoazine is formally monoan-
ionic, PNP0 coordinated through an amide nitrogen and
two phosphoruses, forming thereby a bicyclic pincer-
type structure with an inequal size of the rings. This
structure resembles those of unsymmetrical PCP0 pincer
ligands of Eberhard et al. [9,10] (2, 3) who claim the syn-
thesis of the first pincers with the inequal rings and doc-
ument their advantages when used as catalysts.
Moreover, the ene-hydrazone ligand frame represents
one of the still rare examples of late transition metal am-
ido complexes. While a few examples of amido complex-
*
Corresponding author. Tel.: +42-02-039-0356; fax: +42-02-092-
0661.
ˇ
E-mail address: cermark@icpf.cas.cz (J. Cermak).
´
0020-1693/$ - see front matter ꢀ 2004 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2004.06.022

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J. Storch et al. / Inorganica Chimica Acta 357 (2004) 4165–4171
es with nickel triad metals were known for some time
[11–14], there is currently a renewed interest in them mo-
tivated by their intermediacy in the metal-catalyzed
hydroamination [15,16]. Also, square planar Ni, Pd
and Pt complexes with a rigid donor-amide-donor
framework are believed to show an unusual reactivity
due to the presence of a strongly electron-donating
amide trans to the potential reaction site [17,18].
Since only a couple of ene-hydrazone diphosphinoa-
zine transition metal complexes are known in the litera-
ture [5,19,20], all of them with only one example from
the diphosphinoazine family (the phenyl derivative),
we report here a simple synthesis of such palladium(II)
complexes with the chlorine atom covalently bonded
trans to the amide nitrogen, as suitable precursors for
other amido complexes. In addition to that, we bring
the first example of an (E,E)-tetradentate diphosphinoa-
zine coordination mode.
2J(PP)=11.9 Hz, 4J(PP)=4.4 Hz), 3.89 (2H, dd,
2J(PP)=9.7 Hz, 4J(PP)=5.3 Hz); 13C{1H} NMR
1
(CDCl3): 15.10 (d, J(PC)=10.7 Hz, CH2P), 17.91 (s,
(CH3)2CH), 18.35 (d, 2J(PC)=3.2 Hz, (CH3)2CH),
18.61 (s, (CH3)2CH), 19.09 (d, 2J(PC)=2.0 Hz,
(CH3)2CH), 24.02 (dd, 1J(PC)=20.2 Hz, 3J(PC)=4.0
1
3
Hz, CH), 24.44 (dd, J(PC)=18.9 Hz, J(PC)=3.0 Hz,
CH), 27.36 (s,(CH3)3C), 29.19 (s, (CH3)3C), 33.90 (d,
1J(PC)=19.6 Hz, CH2P), 41.08 (s, (CH3)3C), 42.09 (d,
3J(PC)=6.0 Hz), 174.18 (s, C‚N), 194.48 (d,
2J(PC)=6.0 Hz, C‚N).
2.4. [PdCl{P(C6H11)2CH2C(But)‚NN‚C(But)CH2P-
(C6H11)2}]Cl, 5b, yield 98%
31P{1H} NMR (CDCl3): 58.7, 71.0 (AB, 2J(PP)= 437
Hz); 1H NMR (CDCl3): 1.1–2.4 (44H, bm), 1.26 (9H, s),
1.46 (9H, s), 2.69 (2H, bdd, 2J(PP)=11.4 Hz,
4J(PP)=3.5 Hz), 4.00 (2H, bs); 13C{1H} NMR (CDCl3):
15.53 (d, 1J(PC)=8 Hz, CH2P), 25.43 (s, CH2), 25.72 (s,
CH2), 26.27 (s, CH2), 26.51 (s, CH2), 27.34 (s, (CH3)3C),
27.70 (s, CH2), 27.86 (s, CH2), 28.97 (s, (CH3)3C), 29.54
2. Experimental
1
3
2.1. General
(s, CH2), 32.73 (dd, J(PC)=19.0 Hz, J(PC)=4.2 Hz,
PCH), 33.79 (dd, 1J(PC)=17.5 Hz, 3J(PC)=3 Hz,
PCH), 34.19 (d, 1J(PC)=19.3 Hz, CH2P), 41.16 (s,
All the manipulations were carried out in an inert at-
mosphere of nitrogen or argon using standard Schlenk
techniques. Hexane and heptane were distilled from
Na, diethyl ether from sodium benzophenone ketyl,
chloroform and dichloromethane (Lachema a.s.) were
used as received. Starting [PdCl2(CH3CN)2] [21],
[PdCl2(C6H5CN)2] [22] and the diphosphinoazines [6]
were prepared according to literature methods, triethyl-
3
C(CH3)3), 41.93 (d, J(PC)=5.9 Hz, C(CH3)3), 174.42
2
(s, C‚N), 194.1 (d, J(PC)=5.2 Hz, C‚N).
2.5. [PdCl{PBut2CH2C(But)‚NN‚C(But)CH2PBut2}]-
Cl, 5c, yield quantitative
31P{1H} NMR (CDCl3): 78.4, 81.3 (AB, 2J(PP)= 425
1
amine (Aldrich) was dried by KOH and distilled. H,
1
Hz); H NMR (CDCl3): 1.36 (9H, s), 1.49 (9H, s), 1.52
31P{H}, and 13C{H}, spectra were measured on a Vari-
an Mercury 300 spectrometer at 299.98, 80.98 and 75.44
MHz, respectively, in CDCl3 solvent unless stated other-
wise. Chemical shifts are reported in ppm (d) relative to
TMS, referenced to hexamethyldisilane and external
H3PO4 (31P{H}).
(18H, d, 3J(PP)=3.1 Hz), 1.57 (18H, d, 3J(PP)=2.9 Hz),
2.60 (2H, dd, 2J(PP)=6.9 Hz, 4J(PH) not resolved), 4.16
(2H, dd, 2J(PP)=6.3 Hz, 4J(PP)=3.0 Hz); 13C{1H}
NMR (CDCl3): 14.00 (t, J not resolved, CH2P), 29.02
(s, overlapped, (CH3)3CP), 29.06 (s, overlapped,
(CH3)3C), 29.78 (t, /2J(PC)+4J(PC)/=2.4 Hz,
(CH3)3CP), 34.98 (dd, 1J(PC)=12.7 Hz, 3J(PC)=2.9
Hz, CH2P), 37.16 (dd, 1J(PC)=9.8 Hz, 3J(PC)=5.9
Hz, PC(CH3)3), 37.97 (dd, 1J(PC)=7.8 Hz,
3J(PC)=4.9 Hz, PC(CH3)3), 42.18 (s, C(CH3)3), 176.07
(s, C‚N), 195,20 (bs, C‚N).
2.2. Cationic azine diphosphine palladium complexes
An azine diphosphine (1 mmol) in chloroform (15 ml)
was added to a solution of [PdCl2(CH3CN)2] (1 mmol)
in chloroform (15 ml) and the mixture stirred for 2 h un-
der reflux. After cooling to ambient temperature, a small
amount of precipitate was filtered off (if necessary), the
solution was evaporated to a low volume (3 ml) and
the same volume of heptane was added. After one day,
yellow crystals were filtered off and dried under vacuum.
2.6. Preparation of binuclear complex 7
The azine diphosphine 4a (300 mg, 0.7 mmol) and
[PdCl2(CH3CN)2] (538 mg, 1.4 mmol) were mixed in a
Schlenk tube, chloroform (14 ml) was added, and the
mixture stirred for 45 min during which time most of
the solids dissolved. A small amount of precipitate was
filtered off and the solvent slowly evaporated by gas dif-
fusion into toluene. After several weeks yellow–orange
crystals separated, they were filtered off, washed with di-
2.3.
Pri2}]Cl, 5a, yield quantitative
[PdCl{PPri2CH2C(But)‚NN‚C(But)CH2P-
2
31P{1H} NMR (CDCl3): 67.5, 79.6 (AB, J(PP)=439
Hz); 1H NMR (CDCl3): 1.0–1.6 (46H, m), 2.75 (2H, dd,

J. Storch et al. / Inorganica Chimica Acta 357 (2004) 4165–4171
4167
ethyl ether, and dried under vacuum. Yield 406 mg
(78%).
28.98 (s, (CH3)3C), 31.15 (s, (CH3)3C), 33.26 (dd,
1J(PC)=15.6 Hz, 3J(PC)=3.2 Hz, PCH), 33.63 (dd,
1J(PC)=21.0 Hz, 3J(PC)=4.4 Hz, PCH), 39.32 (d,
2.7. [(PdCl2)2({PPri2CH2C(But)‚NN‚C(But)CH2P-
Pri2})], (7)
3J(PC)=14.4 Hz, C(CH3)3), 39.62 (d, J(PC)=2.0 Hz,
3
1
C(CH3)3), 72.53 (d, J(PC)=45.2 Hz, CHP), 149.8 (m,
2
C‚N), 190.24 (d, J(PC)=20.5 Hz, C‚N).
31P-{1H} NMR (DMSO-d6): 65.7; 1H NMR
(DMSO-d6): 1.11–1.52 (24H, m), 1.57 (18H, s), 2.39
2.11.
But2}], 8c, yield 88%
[PdCl{PBut2CH‚C(But)NN‚C(But)CH2P-
2
(2H, m), 3.05 (2H, m), 3.57 (4H, ABX, J(HH)=20.1
Hz, 2J(PP)=12.2 Hz); 13C NMR (DMSO-d6): 19.93
(bs, CH(CH3)2), 20.86 (bs, CH(CH3)2), 27.41 (d,
1J(PC)=29.4 Hz, CH(CH3)2), 28.40 (d, 1J(PC)=27.4
31P–{1H} NMR (CDCl3): 68.5, 99.9 (AB,
1
2J(PP)=409 Hz); H NMR (CDCl3): 1.19 (9H, s), 1.22
1
3
(9H, s), 1.43 (18H, d, J(PP)=19.1 Hz), 1.48 (18H, d,
Hz, CH(CH3)2), 33.09 (s, CH3), 36.22 (d, J(PC)=25.9
3
Hz, CH2), 46.35 (d, J(PC)=7.5 Hz, C(CH3)3), 190.29
3J(PP)=17.9 Hz), 2.10 (2H, dd, 2J(PP)=10.0 Hz,
4J(PP)=2.9 Hz), 4.26 (1H, bs).
(s, C‚N).
2.8. Deprotonation of cationic azine diphosphine palladi-
um complexes
2.12. X-ray structure determination of 7Æ2CDCl3 Æ3H2O
The diffraction-quality crystals of the Pd complex
were grown from CDCl3 solution by slow evaporation
while standing for a week in an NMR tube in air at
room temperature. The picked up crystal was trans-
ferred to Nujol and mounted on a glass fiber in a ran-
dom orientation by silicon fat. Using a Nonius Kappa
CCD diffractometer, diffraction data were collected at
150(1)K (Cryostream Cooler (Oxford Cryosystem))
and analyzed with HKL program package [23].
An eightfold molar excess of triethylamine was added
to a solution of the corresponding cationic complex in
15 ml of dichloromethane and the mixture stirred for
20 min at room temperature. After that, the mixture
was evaporated to dryness and extracted three times
with 2 ml each of dry hexane or diethyl ether (8a). Com-
bined extracts were evaporated and the red product
dried under vacuum.
The structure was solved by direct methods and re-
fined by full-matrix least-squares techniques (SIR92
[24], SHELXL-97 [25]). Final geometric calculations were
carried out with a recent version of PLATON program
[26]. Scattering factors for neutral atoms used were in-
cluded in the program SHELXL-97. The hydrogens
bonded to C-atoms were kept in theoretical positions
2.9.
Pri2}], 8a, yield 71%
[PdCl{PPri2CH‚C(But)NN‚C(But)CH2P-
31P-{1H} NMR (CDCl3): 57.8, 78.1 (AB, 2J(PP)=
1
415 Hz); H NMR (CDCl3): 1.00–1.45 (28H, m), 1.18
2
(9H, s), 1.26 (9H, s), 2.08 (2H, dd, J(PP)=10.6 Hz,
4J(PP)=3.5 Hz), 2.21 (2H, m), 2.36 (2H, m), 3.78 (1H,
(SHELXL-97), the hydrogen atoms of water molecules
2
4
dd, J(PP)=5.9 Hz, J(PP)=2.9 Hz); 13C–{1H} NMR
were not found and could not be included in calculation.
The rather high remaining peak was observed in final
Fourier difference map probably due to bad quality of
the crystal used.
1
(CDCl3): 10.18 (dd, J(PC)=13.8 Hz, J(PC)=2.3 Hz
3
3
CH2P), 17.62 (d, J(PC)=2.3 Hz, CH3CH), 18.43 (m,
1
3
CH3CH), 23.66 (dd, J(PC)=16.4 Hz, J(PC)=3.2 Hz,
PCH), 24.30 (dd, 1J(PC)=26.3 Hz, 3J(PC)=4.2 Hz,
PCH), 28.87 (s, (CH3)3C), 31.04 (s, (CH3)3C), 39.24 (d,
3J(PC)=14.7 Hz, C(CH3)3), 39.49 (d, J(PC)=2.0 Hz,
3. Results and discussion
3
1
C(CH3)3), 71.51 (d, J(PC)=45.8 Hz, CHP), 149.56 (s,
2
C‚N), 190.71 (d, J(PC)=21.0 Hz, C‚N).
Diphosphinoazines 4a–c with isopropyl, cyclohexyl
and tert-butyl substituents on donor phosphorus atoms
reacted with bis(benzonitrile)palladium(II) chloride in
an equimolar ratio in chloroform at room temperature
(Scheme 1) with the formation of a mixture of two prod-
ucts in aproximately 3:1 ratio, cationic trans- (E,Z)
chelated complexes 5a–c and insoluble coordination pol-
ymers 6a–c, respectively, i.e., exactly in the same way as
the phenyl analog 4d did [8]. In addition to that, a very
small amount of another compound, 7, crystallized out
in the NMR tube from the CDCl3 solution after the
spectra of 5a were taken; the quality of crystals was suf-
ficient for X-ray diffraction measurement (vide infra).
2.10.
CH2P(C6H11)2}], 8b, yield 71%
[PdCl{P(C6H11)2CH‚C(But)NN‚C(But)-
31P–{1H} NMR (CDCl3): 49.2, 68.0 (AB, J(PP)=
1
416 Hz); H NMR (CDCl3): 1.00–2.20 (44H, m), 1.17
2
2
(9H, s), 1.25 (9H, s), 2.08 (2H, dd, J(PP)=10.2 Hz,
4J(PP)=3.2 Hz), 3.72 (1H, dd, J not resolved); 13C–
{1H} NMR (CDCl3): 11.42 (d, 1J(PC)=12.7 Hz,
CH2P), 26.02 (s, CH2), 26.26 (s, CH2), 26.58 (s, CH2),
26.78 (s, CH2), 26.87 (s, CH2), 27.05 (s, CH2), 27.24 (s,
CH2), 27.91 (s, CH2), 28.25 (s, CH2), 28.32 (s, CH2),

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J. Storch et al. / Inorganica Chimica Acta 357 (2004) 4165–4171
PBut2
t-Bu
O
PPri2
PR2
MLn
PR2
N
Cl
Cl
PPri2
Pd
O
Pd
O
N
PPri2
t-Bu
1
2
3
Cl
t-Bu
t-Bu
PR2
PR2
t-Bu
(C6H5CN)2PdCl2
R2P
N
P
dCl2
N
Pd
Cl
N
+
N
N
PR2
N
PR2
n
R2P
t-Bu
t-Bu
t-Bu
4a, R = Pri
5a, R = Pri
6a, R = Pri
4b, R = c-C6H11
4c, R = But
4d, R = Ph
5b, R = c-C6H11
5c, R = But
6b, R = c-C6H11
6c, R = But
t-Bu
Pd
t-Bu
+
N
N
Pri2P
PPri2
Pd
Cl
Cl
Cl
Cl
7, R = Pri
Scheme 1.
Since we supposed that only the cationic complexes are
precursors for the desired ene-hydrazone pincer com-
plexes, we sought for an alternative starting palladi-
the proper ratio of 2:1 (Scheme 3). The yellow–orange
product was air-stable and insoluble in common
organic solvents except dipolar aprotic ones. X-ray dif-
fraction showed it to be a 2:1 palladium–diphosphino-
azine complex with a new coordination mode of the
diphosphinoazine viz. (E,E)-tetradentate coordination
with two separate P, N chelated five membered rings
(Fig. 1). Selected bond lengths and angles are shown
in Table 2. The compound crystallized as a solvate with
two chloroform and three water molecules, the latter
probably coming from the adventitious moisture during
slow evaporation in air. The crystals were in the form
of racemic twins and the molecule exhibited axial chi-
rality caused by hindered rotation around N–N bond
due to the presence of chlorine atoms on palladiums
and the two tert-butyl groups on sp2 carbons next to ni-
trogens. The angle between the least-squares-planes of
the two five membered rings was 87.5ꢁ with one of
the five-membered rings almost planar (ring 2, maxi-
um(II)
complex.
Indeed,
by
refluxing
the
diphosphinoazines in chloroform with bis(acetonitri-
le)palladium(II) chloride prepared in situ, we were able
to obtain the desired compounds 5a–c in high yields
(Scheme 2). NMR spectra of the yellow complexes were
very similar to each other as far as the diphosphinoazine
ligand frame is concerned, the differences were naturally
stemming from different substituents on phosphoruses.
2
Large J(PP) between 425 and 439 Hz showed that in
the complexes phosphorus atoms are mutually trans,
the existence of two different methylene group signals
in 1H and 13C spectra confirmed the terdentate structure
with one of the nitrogens coordinated by an electron
pair. The known palladium phenyl analog [8] and nickel
analogs [27] exhibit the same features.
The preparation of 7 has also been improved by us-
ing the palladium(II) benzonitrile complex and 4a in
˚
mum deviation 0.055 A), while the other was in a more

J. Storch et al. / Inorganica Chimica Acta 357 (2004) 4165–4171
4169
Cl
t-Bu
t-Bu
PR2
PR2
(CH3CN)2PdCl2
N
Pd
Cl
PR2
N
N
N
R2P
t-Bu
t-Bu
4a, R = Pri
5a, R = Pri
4b, R = c-C6H11
4c, R = But
5b, R = c-C6H11
5c, R = But
Scheme 2.
t-Bu
t-Bu
N
t-Bu
PR2
2 (C6H5CN)2PdCl2
N
N
N
Pri2P
PPri2
Pd
Pd
Cl
Cl
R2P
Cl
Cl
t-Bu
4a, R = Pri
7, R = Pri
Scheme 3.
˚
usual conformation with C(1) over the plane (0.213 A)
and C(2) together with P(1) under the plane (0.117 and
˚
0.169 A, respectively). The deviations from planarity of
square planar palladium coordination polyhedron were
were diastereotopic showing a doublet of AB systems
which collapsed into an AB system after decoupling
from 31P. Similarly, signals of CH protons of isopropyl
groups in 1H spectra were inequivalent forming
multiplets with considerable difference in chemical
shifts (2.39 and 3.05 ppm) which collapsed into seven-
line multiplets after phosphorus decoupling, as
expected.
˚
smaller (0.087 and 0.041 A). The chirality was pre-
served in solution, too. The two phosphorus atoms as
well as the two tert-butyl proton and carbon signals
were equivalent in NMR spectra but methylene protons
Fig. 1. ORTEP view of 7. Hydrogen atoms are omitted for clarity.

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J. Storch et al. / Inorganica Chimica Acta 357 (2004) 4165–4171
Table 1
Experimental data for the X-ray difraction of 7Æ2CDCl3 Æ3H2O
Table 2
˚
Selected bond lengths [A] and angles [ꢁ] for 7Æ2CDCl3 Æ3H2O with
e.s.d.s. in parentheses
Formula
M
C26H58Cl10N2O3P2Pd2
1075.98
150(1)
Cl(1)–Pd(1)
Cl(2)–Pd(1)
N(1)–Pd(1)
P(1)–Pd(1)
C(1)–P(1)
2.377(2)
2.297(2)
2.080(8)
2.202(2)
1.808(10)
1.515(12)
1.354(10)
1.536(14)
1.824(10)
1.800(12)
1.403(10)
Cl(3)–Pd(2)
Cl(4)–Pd(2)
N(2)–Pd(2)
P(2)–Pd(2)
C(4)–P(2)
2.393(2)
2.293(2)
2.081(7)
2.192(2)
1.801(9)
1.531(12)
1.298(11)
1.518(13)
1.887(11)
1.879(11)
3.988(1)
T (K)
Crystal dimension (mm)
0.1·0.3·0.3
irregular plate, orange
orthorhombic
P212121 (no. 18)
14.524(5)
14.505(5)
21.477(5)
90
Shape and colour
Crystal system
Space group
a (A)
C(1)–C(2)
C(2)–N(1)
C(2)–C(61)
C(11)–P(1)
C(21)–P(1)
N(1)–N(2)
C(3)–C(4)
C(3)–N(2)
C(3)–C(51)
C(31)–P(2)
C(41)–P(2)
Pd(1) – Pd(2)
b (A)
c (A)
a (ꢁ)
b (ꢁ)
90
90
c (ꢁ)
U (A3)
4525(2)
4
1.580
Cl(2)–Pd(1)–P(1)
Cl(1)–Pd(1)–N(1)
Cl(1)–Pd(1)–Cl(2)
N(1)–Pd(1)–P(1)
C(1)–P(1)–C(11)
C(1)–P(1)–C(21)
Pd(1)–P(1)–C(1)
C(21)–P(1)–C(11)
C(11)–P(1)–Pd(1)
C(21)–P(1)–Pd(1)
C(2)–N(1)–N(2)
C(61)–C(2)–N(1)
C(1)–C(2)–N(1)
C(2)–C(1)–P(1)
91.1(1)
95.9(2)
Cl(4)–Pd(2)–P(2)
Cl(3)–Pd(2)–N(2)
Cl(3)–Pd(2)–Cl(4)
N(2)–Pd(2)–P(2)
C(4)–P(2)–C(31)
C(4)–P(2)–C(41)
Pd(2)–P(2)–C(4)
C(31)–P(2)–C(41)
C(31)–P(2)–Pd(2)
C(41)–P(2)–Pd(2)
C(3)–N(2)–N(1)
C(51)–C(3)–N(2)
C(4)–C(3)–N(2)
C(3)–C(4)–P(2)
88.2(1)
96.0(2)
Z
Dcalc (gcmꢀ3
)
89.8(1)
83.4(2)
91.7(1)
83.9(2)
˚
k (A)
0.71069
1.485
2176.0
l (mmꢀ1
F(000)
)
105.7(5)
102.1(5)
99.6(3)
109.5(5)
107.4(5)
102.3(3)
106.9(6)
117.0(3)
113.4(4)
120.2(7)
130.2(8)
114.3(8)
114.6(6)
h Range of data collection (ꢁ)
Index ranges
1.40–27.10
h: ꢀ17, 18; k: ꢀ16, 18;
l: ꢀ27, 27
38,890
112.2(5)
116.8(4)
117.6(4)
121.7(7)
131.5(8)
109.6(8)
115.0(6)
Number of reflections measured
Rr
0.0471
Number of reflections observed [I>2r(I)] 8865
Number of independent reflections
9746
0.0568
Rint
Coefficients in weighting schemea
Data, restrains, parameters
Goodness-of-fit on F2
Final R, R0 indices [Iꢁ2r(I)]b
Maximum shift (e.s.d.)
Largest difference peak and hole (eA3)b
a
0.0872, 2.3892
9746, 0, 403
1.081
c, nevertheless large enough (409–416 Hz) to confirm
trans arrangement of phosphorus atoms. The ene-hydra-
zone ligand frame followed from the presence of me-
thine proton signals at 3.78, 3.72, and 4.26 ppm for
8a, 8b, and 8c, with half of the integral intensity of the
methylene signals at 2.08, 2.08, and 2.10 ppm, respec-
tively. Both methylene and methine protons were cou-
pled to both phosphorus atoms forming generally
doublets of doublets; methine signals of cyclohexyl
and tert-butyl derivatives were broad. Ene-hydrazone
coordination was further confirmed by disappearance
of one of the methylene carbon signals and appearance
0.0498, 0.1271
0.029
1.24, ꢀ0.66
w=1/[r2(Fo2)+(A P)2 +B P] where P=(Fo2 +2Fc2)/3 (SHELXL
-
*
*
97, Ref. [25]).
b
P
P
P
P
R0=[ w(Fo ꢀFc2)2/ w(Fo2)2]1/2
2
R ¼
j F o ꢀ F c j = j F c
j
(
SHELXL-97, Ref. [25]).
Complexes 5a–c reacted with excess triethylamine
yielding targeted title complexes 8a–c with deprotonated
ene-hydrazone ligand frame (Scheme 4). The red prod-
ucts showed AB systems in 31P NMR spectra with
2J(PP) somewhat smaller than cationic complexes 5a–
1
of methine carbon signal around 72 ppm with J(PC)
coupling about 45 Hz for all the complexes. The spectra
Cl
t-Bu
t-Bu
PR2
PR2
NEt3
N
Pd
Cl
PR2
N
Pd
Cl
PR2
N
N
t-Bu
t-Bu
5a, R = Pri
8a, R = Pri
5b, R = c-C6H11
5c, R = But
8b, R = c-C6H11
8c, R = But
Scheme 4.

J. Storch et al. / Inorganica Chimica Acta 357 (2004) 4165–4171
4171
ˇ
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4. Supplementary material
Table 1 gives pertinent crystallographic data. Crystal-
lographic data for the structures reported in this paper
have been deposited with the Cambridge Crystallo-
graphic Data Centre as supplementary publication num-
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Copies of the data can be obtained free of charge on
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Acknowledgements
The authors thank Mr. M. Grus for skillful experi-
mental assistance and Grant Agencies (GA AS CR:
A4072005; GA CR: 203/01/0554; 203/99/M037) for
support.
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