Synthesis, characterisation and catalytic of Pd(II) and Ni(II) complexes with new cyclic α-diphenylphosphino-ketoimines. Crystal structure of 2,6-diisopropyl-N-(2-diphenylphosphino-cyclopentylidene)aniline and of 2,6-diisopropyl-N-(2-diphenylphosphino-cyclohexylidene)aniline

Journal of Organometallic Chemistry 662 (2002) 150Á171

/

www.elsevier.com/locate/jorganchem

Synthesis, characterisation and catalytic activity of Pd(II) and Ni(II)

complexes with new cyclic a-diphenylphosphino-ketoimines. Crystal

structure of 2,6-diisopropyl-N-(2-diphenylphosphino-

cyclopentylidene)aniline and of 2,6-diisopropyl-N-(2-

diphenylphosphino-cyclohexylidene)aniline

Wilhelm Keim ^a, Stefan Killat ^b, Cosimo F. Nobile ^c, Gian Paolo Suranna ^c,*,

Ulli Englert ^d, Ruimin Wang ^d, Stefan Mecking ^e, Dirk Lucas Schroder ^a

¨

^aInstitut fur Technische und Makromolekulare Chemie der RWTH, Worringer Weg 1, D-52074 Aachen, Germany

¨

^bWacker Polymer Systems GmbH&Co.KG, Postfach 1560, D-84483 Burghausen, Germany

^cSezione Chimica del D.I.C.A. Politecnico di Bari, and centro CNR ICCOM, sezione di Bari, via Orabona 4, I-70126 Bari, Italy

^dInstitut fur Anorganische Chemie der RWTH, Prof. Pirlet Str. 1, D-52074 Aachen, Germany

¨

^eInstitut fur Makromolekulare Chemie, Albert-Ludwigs Universitat Freiburg, Stefan Meier Str. 31, D-79104 Freiburg, Germany

¨

Received 29 April 2002; accepted 5 September 2002

Abstract

New cyclic a-diphenylphosphino-ketoimines have been synthesised by deprotonation of the corresponding imine and subsequent

reaction with chlorodiphenylphosphine. The crystal structures of two of these compounds containing a cyclopentylidene and

cyclohexylidene backbone are discussed. Reaction of these bidentate phosphorusÁ

nitrogen (P^ﬄN) ligands with (cod)Pd(CH₃)Cl

/

leads to neutral complexes of the general formula (P^ﬄN)Pd(CH₃)Cl which have been reacted with AgSbF₆to yield cationic

complexes of formula [(P^ﬄN)Pd(CH₃)(NCCH₃)]SbF₆. Reaction of these ligands with (1,2-dimethoxyethane)NiBr₂yields neutral

nickel(II) complexes that have been characterised by IR and elemental analysis. Cationic Pd(II) complexes as well as MAO-activated

neutral nickel(II) complexes have been used as ethylene oligomerisation catalysts. The cationic palladium(II) complexes show a

marked pressure dependence of TOF, with a-olefin fraction and Schulz-Flory a-values explainable in the light of the accepted

mechanism for analogous complexes. By increasing the steric bulkiness of the substituent on the imine, or by using ligands with

cyclohexylidene or cycloheptylidene backbone instead of cyclopentylidene, a drop in catalytic activity is observed. Nickel(II)

complexes of the title ligands activated with MAO permit to confirm the latter conclusions. In comparison with palladium their use

brings to comparable linearities but higher oligomerisation grades as well as a-olefin fraction. Cationic palladium(II) complexes are

also active in the propene and 1-butene oligomerisation.

Keywords: Palladium; Nickel; Methyl complexes; Phosphino ketoimines; Ethylene oligomerisation

1. Introduction

tance mainly lies in the different trans-effect due to the

different s-donor and p-acceptor properties of phos-

phorus and of the heteroatom. This accounts for the

importance of such ligands for applications in homo-

genous catalysis, for example the selectivity control in

ethylene oligomerisation [2] or the CO migratory inser-

Bidentate ligands based on a phosphine and an

additional donor atom such as oxygen, sulphur or

nitrogen possess intriguing features [1]. Their impor-

tion into a Pdꢀ

/

CH₃bond [3].

In this framework, P^ﬄN ligands are important

because of their peculiar features [4]. Nitrogen donor

atoms in most P^ﬄN bidentate ligands reported in the

* Corresponding author. Tel.: ꢀ

0611

E-mail address: surannag@poliba.it (G.P. Suranna).

/

39-80-546-0608; fax: ꢀ39-80-546-

/

PII: S 0 0 2 2 - 3 2 8 X ( 0 2 ) 0 1 9 0 3 - 4

W. Keim et al. / Journal of Organometallic Chemistry 662 (2002) 150Á

/

171

151

Nomenclature

cod

1,5-cyclooctadiene

dppCyPentMA

dppCyPentPA

dppCyHexMA

dppCyHexPA

dppCyHexMOA

dpptBuCyHexPA

dppCyHeptPA

dppHeptPA

2,6-dimethyl-N-(2-diphenylphosphino-cyclopentylidene)aniline

2,6-diisopropyl-N-(2-diphenylphosphino-cyclopentylidene)aniline

2,6-dimethyl-N-(2-diphenylphosphino-cyclohexylidene)aniline

2,6-diisopropyl-N-(2-diphenylphosphino-cyclohexylidene)aniline

2-methoxy-N-(2-diphenylphosphino-cyclohexylidene)aniline

2,6-diisopropyl-N-[4-tert-butyl-2-diphenylphosphino-cyclohexylidene)]aniline

2,6-diisopropyl-N-(2-diphenylphosphino-cycloheptylidene)aniline

2,6-diisopropyl-N-(2-diphenylphosphino-1-n-propyl-butylidene)aniline

As part of our continuing interest in P^ﬄE ligands [20

23] (Eꢁoxygen, sulphur or nitrogen), we lately started

to investigate the behaviour towards palladium(II) and

nickel(II) of a-diphenylphosphino ketoimines, the gen-

eral formula of which is described in Fig. 1.

An a-diphenylphosphino-ketoimine derived from the

linear ketone heptane-4-one has also been synthesised

for comparison. The catalytic activity of their cationic

palladium(II) complexes or of their nickel(II) complexes

(the latter in association with MAO) in the ethylene

oligomerisation reaction has also been investigated.

literature bind to an aromatic system or are in the form

of an amino- or imino- group. An important property of

this class of compounds is the wide possibility to fine-

tune the stereoelectronic features of the ligands, provid-

ing potential for tailoring. This advantage has been

exploited for the synthesis of palladium and platinum

complexes of several phosphino-imines [5]. The coordi-

nation of these P^ﬄN ligands is influenced by the

phosphine functionality and by the s-donor capacity

of the lone pair on nitrogen while a p-coordination of

Á

/

the Cꢁ

/

N double bond is only rarely observed in the case

of imines [6]. Methyl palladium complexes of several

phosphino-benzaldimines have been synthesised for a

better understanding of an in situ ethylene oligomerisa-

tion catalytic system comprising palladium acetate, one

equivalent of P^ﬄN ligand and two equivalents of p-

tolyl-sulfonic acid [7]. Palladium complexes of o-(diphe-

nylphosphino)-N-benzaldimine derivatives have re-

cently received much attention as catalysts for the

Heck reaction [8] as well as for the alkene/CO copoly-

merisation [9], also providing a useful insight into

reaction mechanisms [10]. An interesting alternative to

the P^ﬄN ligands with a benzaldimine backbone are

ligands with pyrrolimine and dihydroxyoxazoline back-

bone which have originally been designed for asym-

metric catalysis [11] and have recently been used in the

palladium catalysed allylic substitution [12]. The induc-

tive effect of these ligands has also been exploited for the

CO/styrene [13] or CO/ethylene copolymerisation [14].

Phosphino-imines have also been used as ligands in the

palladium catalysed alkynylstannylation [15] or in the

alkoxycarbonylation [16] of alkynes. A phosphino-imine

palladium complex was used as catalyst for the oxidative

homocoupling reaction of organostannanes using air as

oxidant [17]. Also cross-coupling of various types of aryl

halides with alkynyl-, alkenyl- and arylstannanes have

been catalysed by palladium(II) complexes with phos-

phino-imines [18]. Recently, the synthesis of an a-

2. Results and discussion

2.1. Synthesis of phosphino ketoimines

The synthesis of the a-(diphenylphosphino)-ketoi-

mines has been accomplished through condensation

reaction between suitable ketones and anilines followed

by a-deprotonation of the obtained ketoimines and

reaction with P-chloro-diphenylphosphine. The synthe-

sised ketoimines are reported in Table 1.

The deprotonation of an imine to yield an 1-aza-allyl

anion is of great practical importance in organic

chemistry [24]. Although the use of MeLi, n-BuLi or

of Grignard reagents is generally not advisable because

of the addition side-reactions that can occur to the Cꢁ

/

N-Ar double bond, carrying out comparative syntheses

using LDA and n-BuLi resulted in no difference in the

final product. Since the use of LDA requires more

difficult purification, n-BuLi was used as deprotonating

agent. The steric hindrance of the formed imines is held

responsible for the absence of addition reaction.

Contrary to the phosphino-imine reported by Green

[19], where the formation of E and Z isomers in the

diphenylphosphino-ketoimine

of

formula

[Ph₂PCH₂C(Ph)ꢁN(2,6-Me₂C₆H₃)] has been reported,

/

together with the study of its palladium(II) complexes

[19].

Fig. 1. a-(Diphenylphosphino) cyclic ketoimines (Arꢁ

/2,6-dimethyl-

phenyl or 2,6-diisopropylphenyl, nꢁ1Á3).

/

152

W. Keim et al. / Journal of Organometallic Chemistry 662 (2002) 150Á171

/

Table 1

observed for 1 and 2, respectively. The ³¹P-NMR

integral ratio allows a rough evaluation of the imine/

enamine ratio in CDCl₃at 20 8C: 5.7 for 1 and 4.0 for 2.

Concerning the other synthesised ligands, the imine/

enamine equilibrium was not observed in CDCl₃solu-

tion for 3, 4, 7 and 8, as monitored by ³¹P{¹H}-NMR

spectroscopy.

Ketoimines p-1 Áp-8

/

b

R¹, R²

R³

R⁴

Label

2.2. Crystal structural aspects of ligands 2 and 4

a

ꢀ(CH₂)₄ꢀ

ꢀ(CH₂)₅ꢀ

Me

i-Pr

Me

i-Pr

H

Me

p-1

p-2

p-3

p-4

p-5

p-6

p-7

p-8

i-Pr

Me

The conformation of the new chelating ligands 2 and

4 has been disclosed by single crystal X-ray diffraction.

The crystals have been obtained by precipitation from

methanol and confirm the proposed imine structure.

Ligands 2 and 4 crystallise in centrosymmetric space

groups, i.e. as racemic crystals containing both R and S

enantiomers. In Figs. 4 and 5 are shown the molecular

structures of ligands 2 and 4.

i-Pr

OMe

i-Pr

ꢀ(CH₂)₂ꢀCH^tBuꢀ(CH₂)₂ꢀ

ꢀ(CH₂)₆ꢀ

n-C₃H₇, n-C₃H₇

i-Pr

a

Literature known ketoimines (details are given in the Supplemen-

tary Material).

b

Geometrical parameters found in the structures of 2

N bond distance

See Section 3.

and 4 and, in particular, the Cꢁ

/

3

˚

[1.2588(17) A in (2) and 1.267(2) A in (4)], the C(sp )ꢀ

/

ratio 85:15 is reported, in our case the electrophilic

attack of the chlorophosphine on the 1-aza-allyl anion

takes place for steric reasons on the opposite side of the

aryl functionality so that only the anti-substituted imine

is formed as a racemate (Fig. 2). The imine form of the

synthesised ligands is depicted in Table 2. Ligand 6,

which was synthesised in order to study the effect of

reducing the ligand backbone flexibility on catalytic

activity (vide infra), is obtained as a mixture of

diastereoisomers.

Elemental analyses as well as mass spectrometry

confirmed the proposed molecular formula for all

ligands. Although in the solid state ligand 2 apparently

exists only in the imine form (vide infra), solution NMR

at room temperature supports an imine/enamine tau-

tomery for the cyclopentylidene ligands 1 and 2, as also

recently observed for similar cyclic phosphino-ketoi-

mines [25]. The equilibrium is shown in Fig. 3. The

depicted enamine structure is in our opinion favoured by

the possibility of further delocalisation on phosphorus.

The ³¹P{¹H} chemical shift of the phosphine function-

˚

P bond distance [1.8458(16) A in (2) and 1.881(2) A in

(4)] are in the range found for analogous compounds

[26]. A list of relevant crystallographic data is given in

Table 3, while selected bond distances and angles are

given in Table 4.

The cycloalkylidene backbone is in the thermodyna-

mically favoured envelope conformation (2) or in the

chair conformation (4). An almost perpendicular ar-

rangement between the aromatic ring and the planes

N1ꢀ

/

C11ꢀ

/

C12 (2) or Nꢀ

/

C1ꢀ

/

C2 (4) places the bulky

isopropyl substituents above and below this latter plane.

These conformations are compatible with the bis-imino

ligands described by Brookhart and Gibson [27].

While k²-P,N coordination can occur for 2 without

major ligand distortion, for compound 4 a ring inversion

is required. Fig. 6 shows how the phosphine function-

ality is displaced from the axial to the equatorial

position to permit a chelating coordination to the metal.

2.3. Neutral palladium(II) methyl complexes

ality lies at dꢁ

enamine, values of dꢁ

/

ꢂ

/

6.6 and ꢂ

/

6.7 ppm, while for the

The synthesised a-diphenylphosphino-ketoimines

have been used as ligands for the preparation of the

neutral palladium(II) complexes listed in Table 2.

Methyl palladium complexes have been chosen because

/

ꢂ

/

30.3 and dꢁ

/

ꢂ

/

30.5 ppm are

of their importance in catalytic Cꢀ/C bond forming

reactions. The synthetic approach envisages cycloocta-

diene exchange by reaction of (cod)Pd(CH₃)Cl with one

equivalent of bidentate ligand, as depicted in Fig. 7. The

main ³¹P{¹H}-, ¹³C{¹H}-NMR and IR spectroscopic

features of all synthesised ligands and complexes are

reported in Table 5.

All reported spectroscopic data for neutral complexes

9, 12, 15, 18, 21, 23, 26 and 29 prove a k²-P,N square

planar coordination of the synthesised phosphino ke-

Fig. 2. Followed approach in the synthesis of a-(diphenylphosphino)-

ketoimines exempliﬁed for 2.

W. Keim et al. / Journal of Organometallic Chemistry 662 (2002) 150Á

/

171

153

Table 2

Synthesised ligands and complexes

toimines and a cis configuration of the methyl group

with respect to phosphorus. A strong downfield shift in

Mass spectrometry analysis of the synthesised neutral

complexes is straightforward by SIMS spectrometry in

3-nitrobenzylalcohol (NBA). In all cases, the highest

³¹P{¹H}-NMR ranging from Ddꢁ

/49.35 ppm (12) to

Ddꢁ

/

62.64 ppm (26) with respect to the free ligand,

molecular weight peak is seen as the anion [Mꢂ

1]^ꢂ,

/

clearly points out the coordination of phosphorus to

palladium [28]. As expected on the basis of the

comparison with similar phosphino-imine complexes

[10b,10c], the coordination of the N donor atom can

be clearly identified by a shift to lower wavenumbers in

thus ruling out the formation of chloro bridged dimeric

complexes with k¹-P coordination as was clearly shown

by the same technique in the case of analogous

palladium methyl complexes with the large byte bisꢂ

/

phosphine monoxide ligand dpppO. Other relevant

the IR spectra. The observed values are in the range ꢂ

46 cm^ꢂ1B 28 cm^ꢂ1. The imine coordi-

Dn(CꢁN)B

nation also causes a downfield shift of the ¹³Cꢁ

N-signal.

/

peaks in the SIMS anion spectrogram of these com-

15]^ꢂdue to the loss of the methyl

group, and different adducts of the chloride ion with the

/

ꢂ

/

plexes are the [Mꢂ

/

154

W. Keim et al. / Journal of Organometallic Chemistry 662 (2002) 150Á171

/

Table 3

Crystal data, data collection parameters and convergence results for

dppCyPentPA (2) and for dppCyHexPA (4)

Table 4

˚

Selected bond distances (A) and angles (8) for ligands (2) dppCyPent-

PA and (4) dppCyHexPA

2

4

2

4

a

Empirical formula

Crystal size (mm)

Crystal system

Space group

C

₂₉H₃₄NP

C₃₀H₃₆NP

0.40ꢃ0.48ꢃ0.52

Triclinic

Bond distances

P1ꢀC15

0.85ꢃ0.53ꢃ0.28

Monoclinic

P2₁/n

1.8458(16)

1.8366(16)

1.8253(18)

1.2588(17)

1.4242(17)

1.512(2)

PꢀC6

1.881(2)

1.832(2)

1.843(2)

1.267(2)

1.429(2)

1.515(2)

1.534(3)

1.527(3)

1.519(3)

1.546(2)

1.510(2)

P1ꢀC30

PꢀC21

PꢀC31

NꢀC1

¯

P1

P1ꢀC36

˚

a (A)

16.8779(13)

16.7624(13)

18.4817(14)

90

10.610(2)

11.637(4)

12.044(4)

72.33(3)

65.56(2)

86.80(2)

1285.7(7)

2

N1ꢀC11

N1ꢀC42

C11ꢀC12

C12ꢀC13

C13ꢀC14

C14ꢀC15

C15ꢀC11

˚

b (A)

NꢀC11

C1ꢀC2

C2ꢀC3

C3ꢀC4

C4ꢀC5

C5ꢀC6

C6ꢀC1

˚

c (A)

a (8)

b (8)

g (8)

1.520(2)

1.511(2)

97.356(3)

90

1.534(2)

1.5109(19)

3

˚

V (A )

5185.7(7)

8

Z

˚

Wavelength l (A)

0.71073

293(2)

1.54184

293

a

Bond angle

Temperature (K)

Scan type

C15ꢀP1ꢀC30

C15ꢀP1ꢀC36

C30ꢀP1ꢀC36

C11ꢀN1ꢀC42

N1ꢀC11ꢀC12

N1ꢀC11ꢀC15

C12ꢀC11ꢀC15

C11ꢀC12ꢀC13

C12ꢀC13ꢀC14

C13ꢀC14ꢀC15

C11ꢀC15ꢀC14

P1ꢀC15ꢀC11

P1ꢀC15ꢀC14

P1ꢀC36ꢀC37

99.74(7)

C6ꢀPꢀC21

C6ꢀPꢀC31

C21ꢀPꢀC31

C1ꢀNꢀC11

NꢀC1ꢀC2

NꢀC1ꢀC6

C2ꢀC1ꢀC6

C1ꢀC2ꢀC3

C2ꢀC3ꢀC4

C3ꢀC4ꢀC5

C4ꢀC5ꢀC6

C1ꢀC6ꢀC5

PꢀC6ꢀC1

103.11(8)

99.56(9)

102.70(8)

121.5(1)

126.7(2)

118.3(2)

115.0(1)

110.7(2)

112.4(1)

111.1(2)

112.5(2)

109.6 (2)

110.5(1)

109.8(1)

v

v Á

4.0Á

/

2u

70.0

103.49(8)

100.92(7)

119.69(12)

128.68(14)

121.93(13)

109.32(13)

104.12(14)

103.92(16)

104.06(15)

103.12(12)

112.11(10)

114.58(12)

118.08(18)

Theta range for data 1.54Á

collection (8)

Diffractometer

/27.45

/

Bruker AXS SMART Nonius CAD4

APEX

Reflections collected 41 234

Independent reflec-

tions

8366

11 847 [R_intꢁ0.0422] 4862 [R_intꢁ0.041]

Reflection observed 6185 [I ꢀ2s(I)]

Absorption correc-

tion

4212 [I ꢀ1s(I)]

Numerical

None

Refinement method Full-matrix least-

squares on F²

Full-matrix least-

squares on F²

Refined isotropically

PꢀC6ꢀC5

Hydrogen treatment Riding with U_isore-

fined

Final R indices (ob- R₁ꢁ0.0445

served data)

Rꢁ0.064

wR₂ꢁ0.1020

wRꢁ0.068

Fig. 3. Imine-enamine tautomeric equilibrium for ligand 2.

Fig. 5. Crystal structure of 2,6-diisopropyl-N-(2-diphenylphosphino-

cyclohexylidene)aniline (4).

Fig. 4. Crystal structure of 2,6-diisopropyl-N-(2-diphenylphosphino-

cyclopentylidene)aniline (2).

Fig. 6. Ring inversion of 4 favouring chelation on a metal centre

(Arꢁ2,6-diisopropyl-C₆H₃).

/

W. Keim et al. / Journal of Organometallic Chemistry 662 (2002) 150Á

/

171

155

Table 5

Relevant spectroscopic data for ligands, and cationic palladium(II) complexes

matrix. In the SIMS cation spectrogram, the highest

molecular peaks observed are always due to the loss of

chloride or of the methyl group.

cis configuration of the methyl group relative to

phosphorus, as the ¹³C{¹H} chemical shift relative to

the same fragment, which is shifted to d $

/

ꢂ4 ppm

/

A ³J_H,Pcoupling constant ranging from 2.4 to 3.3 Hz

[3a,5b] with respect to the precursor. Quite interestingly,

21 seems to be formed as a mixture of isomers in 1:1

ratio due to the unsymmetrical methoxy substituent on

for the doublet of the Pdꢀ

/

CH₃protons in all methyl

complexes except 26 can be invoked as a proof for the

the phenyl ring, as evidenced by the appearance of two

1

close Pdꢀ

/

CH₃signals both in the H (dꢁ

/

0.55 and 0.56

4.6 ppm).

Two singlets appear also for the OCH₃signal both in the

¹H (dꢁ3.70 and 3.80 ppm) and in the ¹³C{¹H}

spectrum (dꢁ55.9 and 56.2 ppm). The corresponding

signals in the ³¹P{¹H} spectrum are at dꢁ

50.22 and

dꢁ50.56 ppm.

ppm) and in the ¹³C{¹H} spectrum (dꢁ

/

ꢂ

/

Fig. 7. Followed approach for the synthesis of neutral and cationic

phosphino ketoimine complexes.

/

156

W. Keim et al. / Journal of Organometallic Chemistry 662 (2002) 150Á171

/

Table 6

Selected IR data for neutral complexes (P^ﬄN)NiBr₂

Number

(P^ﬄCꢁNR)NiBr₂complex

(P^ﬄN)NiBr₂n(CꢁN)/cm^ꢂ1

Dn/cm^ꢂ1respect to ligand

11

14

17

20

25

28

31

(dppCyPentMA)NiBr₂

(dppCyPentPA)NiBr₂

(dppCyHexMA)NiBr₂

(dppCyHexPA)NiBr₂

(dpptBuCyHexPA)NiBr₂

(dppCyHeptPA)NiBr₂

(dppHeptPA)NiBr₂

1642.6; 1625.9

1642.8

1616.7

ꢂ50.7; ꢂ34.0

ꢂ34.3

ꢂ36.3

ꢂ34.6

ꢂ38.4

1616.2

1619.9

1595.4

1571.1

ꢂ41.8

ꢂ62.9

2.4. Cationic palladium(II) methyl complexes

band at about 658 cm^ꢂ1for the synthesised cationic

complexes is clearly attributable to an octahedral

hexafluoroantimonate anion. Of the P^ﬄN cationic

complexes, only 24 is in the form of a diastereoisomeric

mixture due to the presence of the ligand dpptBuCy-

HexPA (6). This aspect considerably complicates the

¹H- and ¹³C{¹H}-NMR interpretation of 24 and of its

precursor 23. However, based on ³¹P{¹H}-NMR, which

Halogenide metathesis with AgSbF₆in the presence of

acetonitrile yielded the corresponding white or light-

yellow cationic complexes listed in Table 2.

SIMS spectrograms obtained in DTT/DTE/Sul (see

Section 3) point out that the palladium complexes are

also monomeric species. Relevant signals are observed

for all complexes at m/z values corresponding to

[(P^ﬄN)Pd(CH₃)]^ꢀin the SIMS cation spectrogram

(loss of the counteranion and of acetonitrile). The

hexafluoroantimonate anion is seen as the only peak

clearly shows two signals at dꢁ

24, and at dꢁ50.15 and 52.09 ppm for 23, on IR data

showing the expected red shift of the imine group

[ꢂ

42.2 cm^ꢂ1in the case of 23 and ꢂ30.0 cm^ꢂ1in the

/53.66 and 54.00 ppm for

/

case of 24], as well as on elemental and mass analysis, it

is safe to assume for the above mentioned complexes,

the structure proposed for the analogous neutral and

cationic compounds.

in the SIMS anion spectrogram (m/zꢁ

ingly, for all complexes but 16 a complex matrix adduct

of the kind [(P^ﬄN)Pdꢀ 1]^ꢀis observed.

DTE/DTTꢂ

/

235). Interest-

/

All spectroscopic data reported for cationic complexes

10, 13, 16, 19, 22, 24, 27 and 30 confirm the k²-P,N

square planar coordination and the cis configuration of

2.5. Neutral nickel bromide complexes

3

the methyl group with respect to phosphorus. The J_H,P

coupling constant ranging from 1.2 to 2.1 Hz for the

Substitution of the weakly coordinating 1,2-di-

methoxyethane in (dme)NiBr₂with the P^ﬄN ligands

permitted the obtainment of neutral nickel(II) com-

plexes in quantitative yields. Selected IR data are

summarised in Table 6. In analogy to the palladium(II)

complexes described above, the chelation of the imine

doublet of the Pdꢀ

/

CH₃protons in almost all cationic

methyl complexes synthesised clearly speaks for a

retention of the cis configuration of the methyl group

relatively to phosphorus after halide metathesis. The

change in nature, from neutral to cationic complexes is

held responsible for a stronger downfield shift in

functionality is proven by a red-shift (ꢂ

/

63 cm^ꢂ1B

/

³¹P{¹H}-NMR that ranges from Ddꢁ

Ddꢁ65.8 ppm with respect to the free ligands. By

comparing the Dn values of CꢁN stretching frequencies

for cationic complexes with respect to the free ligand,

the Dn values are in the range ꢂ Dn(Cꢁ

34.7 cm^ꢂ1B

N)B

15.6 cm^ꢂ1. This observation may tentatively be

/51.1 ppm to

Dn B N double bond stretching.

/

ꢂ

/

34 cm^ꢂ1) of the Cꢁ

Elemental analysis of the synthesised Ni(II) complexes is

in accordance with the proposed structure.

/

2.6. Ethylene oligomerisation

/

ꢂ

/

In order to evaluate the potentiality of the new P^ﬄN

ligands, their cationic palladium complexes have been

used as catalyst for the ethylene oligomerisation reaction

in homogeneous phase. The influence of ethylene

pressure on activity and selectivity was first tested with

ascribed to a stronger back-donation to the coordinated

imine in the case of neutral complexes. The observed

shifts of the ¹³Cꢁ

/

N-signals fall in the range 12.2 ppmB

15.5 ppm with the exception of 22, for which the

Dd(¹³Cꢁ

N) value is only 6.7 ppm. Stabilisation of all

/

Dd B

/

cationic methyl complexes by acetonitrile was moni-

tored by IR. As expected for a large number of nitrile

complexes in general [29], as well as for similar

compounds [10b,10c], the two typical absorptions in

complex 13 in the range 10 bar5

/

P 560 bar. The results

/

obtained by carrying out reactions at constant ethylene

pressure are collected in Table 7.

From the reported data it is evident that, while the

selectivity towards linear products does not considerably

change in the explored range, by raising the pressure

from 10 to 60 bars, a raise in catalyst activity (TOF

the n(Cꢂ

/

N)-region (2200Á

2260 cm^ꢂ1) caused by the

CN stretching are shifted to higher wavenumbers (about

/

50 cm^ꢂ1) by end-on coordination to the metal. A strong

W. Keim et al. / Journal of Organometallic Chemistry 662 (2002) 150Á

/

171

157

Table 7

Ethylene oligomerisation with 13; inﬂuence of the pressure

a

Linearity (%)

a

Terminal olefin fraction (%)

b

Entry

P(ethylene) (bar)

TOF (h^ꢂ1

)

a

C_max

1

2

3

4

5

6

10

20

30

40

50

60

312

407

89.5

88.8

88.1

89.1

89.6

90.5

25.7

26.8

29.0

31.1

33.0

34.8

0.54

0.66

0.61

0.69

0.68

0.72

14

16

20

22

26

662

822

1174

1337

Conditions: 0.05 mmol Pd; 20 ml CH₂Cl₂; Tꢁ70 8C; tꢁ2 h.

In the C₆-fraction.

a

b

aꢁ(mol C₁₀/mol C₈).

Fig. 8. Postulated reaction pathways explaining the pressure dependence of the a-oleﬁn fraction in the Pd(II) catalysed ethylene oligomerisation with

P^ﬄN ligands.

passing from 312 h^ꢂ1at 10 bars to 1337 h^ꢂ1at 60 bars),

ingly a higher ethylene pressure should in principle raise

the ratio of the chain transfer rate versus isomerisation

rate thus leading to higher a-olefin fractions. The

ethylene pressure also influences the reinsertion of

in selectivity towards a-olefin (passing from 25.7% at 10

bars to 34.8% at 60 bars), and in the SchulzÁFlory a-

/

value is observed. This behaviour is in agreement with

the mechanism proposed by Brookhart for ethylene

oligomerisation with diimine complexes [30], as ex-

plained below considering the possible mechanistic steps

of isomerisation and chain transfer. Consequently to the

previously formed olefins [reaction (b)0

/

(e)] that should

¯

also have less influence with raising the ethylene

concentration. The possibility for reinsertion of pre-

viously formed olefins with consequent isomerisation

was proven by the addition of an aliquot of 1-heptene to

an ethylene oligomerisation run with 13 as a catalyst. As

a result, 1-heptene was isomerised to internal heptenes

without being converted to C₉- or higher alkenes.

Furthermore, oligomerisation tests carried out with 1-

hexene or 1-decene as substrates and 13 as catalyst, only

resulted in very low oligomerisation grades and high

isomerisation activity.

raise in SchulzÁFlory a-value, the C_maxvalues are also

/

positively influenced by pressure. These values are

unusually high compared with similar cationic systems

for ethylene oligomerisation [31] (Fig. 8).

Starting from the postulated metal-alkyl species

exhibiting a b-agostic interaction (a) and (c) and from

the hydride species (b), the chain transfer is controlled

¯

by ethylene concentration. The chain isomerisation

starting from the hydride species (b), on the contrary

In order to check the results obtained and discussed

for complex 13, other catalysts have been used as

¯

is not dependent on the ethylene pressure. Correspond-

158

W. Keim et al. / Journal of Organometallic Chemistry 662 (2002) 150Á171

/

Table 8

Ethylene oligomerisation with cationic palladium(II) complexes; inﬂuence of the pressure

a

Linearity (%)

a

Terminal olefin fraction (%)

b

Entry Complex Ligand

P(ethylene) (bar)

TOF (h^ꢂ1

)

a

C_max

1

2

3

4

5

6

10

19

27

dppCyPentMA

dppCyHexPA

dppCyHeptPA

30

40

30

40

30

40

750

1215

155

88.4

90.2

84.4

70.6

75.2

24.4

34.1

25.3

29.7

31.4

35.6

0.67 28

0.73 30

c

Á/

12

424

331

0.65 16

0.67 14

0.72 16

398

Conditions: 0.05 mmol Pd; 20 ml CH₂Cl₂; Tꢁ70 8C; tꢁ2 h.

In the C₆-fraction.

a

b

aꢁ(mol C₁₀/mol C₈).

Not determined because of the low conversion.

c

comparison at 30 and 40 bar of ethylene pressure. The

results are collected in Table 8.

crowded complexes 10 and 16. Interesting results have

been obtained with 22 bearing a methoxy functionality.

On raising the ethylene pressure, complexes 10, 19

and 27, which differ from 13 in steric hindrance on

nitrogen [2,6-dimethylphenyl (10)] or in the cycloalk-

ylidene size [cyclohexylidene (19), cycloheptylidene (27)],

show the expected raise in TOF, a-fraction and C_max

(comparison of entries 1 and 2, 3 and 4, 5 and 6). TOF

rises dramatically with pressure for complexes 10 and 19

while for complex 27 a limited effect is observed

probably because of the more flexible backbone. The

pressure effect on a-fraction is more evident for complex

10 (from 24.4 to 34.1% entries 1 and 2 of Table 8). The

percentage of linear products remains almost unchanged

for complexes 10 and 19, only for complex 27 a raise

from 70.6 to 75.2% being observed.

Not only are the TOFs above the average, and C_max

30 carbon atoms, but also very high selectivity to linear

products (ꢀ96%) distinguishes the catalyst. The meth-

ꢀ

/

oxy group is to be held responsible for these character-

istics. The reasons may be: (a) a different basicity of the

nitrogen donor atom, due to mesomeric effects,

although this should not, in comparison with the alkyl

substituted derivatives, cause any major difference; (b)

an interaction of the methoxy oxygen atom with the

metal centre. This latter effect could directly influence

the electronic properties on palladium but it could also

bring to the blocking of one of the axial positions by

interaction of the methoxy group lone pair with the

metal centre during the catalytic cycle.

The steric crowding in the vicinity of the catalytic

active site may have a considerable effect on activity and

selectivity [32]. All literature results point out a blocking

of the axial position on the metal through the bulky

ligands therefore avoiding the approach of ethylene

from one of these positions, consequently bringing to

higher rates for b-H-elimination. These effects should in

principle be noticeable also by using a-diphenylpho-

sphino-ketoimines catalyst precursors. Moreover, as is

known for P^ﬄO-nickel complexes [33], the limitation of

ligand backbone flexibility brings to higher catalyst

selectivities and oligomerisation grades. In order to

obtain other clues for this behaviour of palladium

complexes with a-diphenylphosphino-ketoimine, ligands

forming five terms metallacycle but with different ligand

backbone have been used in catalysis. In this study,

summarised in Table 9, cyclic as well as open-chain

hydrocarbons have been used as backbone. For the sake

of comparison, entries 1, 2 and 4, that have already been

discussed, are reported again in Table 9.

As to ligand backbone variation, comparing entry 1

with 3 and entries 2 with 4 (same steric hindrance on

nitrogen) the effect of enlarging ligand backbone from

cyclopentylidene to cyclohexylidene clearly shows the

two aforementioned effects: while linearities are slightly

but significantly affected (from 88 to 84% on average

thus evidencing a reduced chelate control consequent to

higher ligand backbone flexibility), the effect on a-

fraction seems to be clear only for complexes 10 and 16

(entries 1 and 3 of Table 9: 24.4 and 32.8%, respectively).

By reducing backbone flexibility of the cyclohexylidene

structure by embodying a t-butyl group into it as in 24

(entry 6, Table 9), a slightly higher TOF and C_maxwere

obtained, while product linearity and a-fraction are

unchanged with respect to 19 (entry 4, Table 9). The

results obtained with complex 27 bearing a cyclohepty-

lidene backbone (entry 5, Table 8) showed a markedly

lower product linearity although both activity and

oligomerisation grades were slightly higher than for

19. Using an open chain alkylidene backbone, as in

complex 30, has the expected effect of a marked

lowering in activity, to the point that a chromatographic

analysis to assess selectivity was hampered (entry 7,

Table 9).

Noteworthy, changing the ortho-substituents on the

aniline from methyl to iso-propyl (comparison of entries

1 and 2 and of entries 3 and 4) points out an almost

identical selectivity to linear products and a slightly

higher activity and oligomerisation grades for the less

W. Keim et al. / Journal of Organometallic Chemistry 662 (2002) 150Á

/

171

159

Table 9

Ethylene oligomerisation with cationic palladium(II) complexes. Inﬂuence of ligand backbone and steric hindrance

a

Linearity (%)

a

Terminal olefin fraction (%)

b)

Entry

Complex

Ligand

TOF (h^ꢂ1

)

a

C_max

1

2

3

4

5

6

7

10

13

16

19

22

24

30

dppCyPentMA

dppCyPentPA

dppCyHexMA

dppCyHexPA

dppCyHexMOA

dpptBuCyHexPA

dppHeptPA

750

662

314

155

1034

258

225

88.4

88.1

83.8

84.4

96.6

24.4

29.0

32.8

25.3

52.3

0.67

0.61

28

20

18

12

34

16

12

0.71

c

Á/

0.74

0.48

0.51

83.1

c

Á/

27.5

c

Á/

Conditions: 0.05 mmol Pd; 20 ml CH₂Cl₂; 30 bar ethylene, Tꢁ70 8C; tꢁ2 h.

In the C₆-fraction.

a

b

aꢁ(mol C₁₀/mol C₈).

Not determined because of the low conversion.

c

Table 10

Ethylene oligomerisation with the in situ catalytic system (P^ﬄN)NiBr₂/MAO

a

Terminal olefin fraction (%)

b

Entry

Complex

TOF (h^ꢂ1

)

Linearity

a

C_max

1

2

3

4

5

6

7

11 (dppCyPentMA)NiBr₂

14 (dppCyPentPA)NiBr₂

17 (dppCyHexMA)NiBr₂

20 (dppCyHexPA)NiBr₂

25 (dpptBuCyHexPA)NiBr₂

28 (dppCyHeptPA)NiBr₂

31 (dppHeptPA)NiBr₂

29 500

8420

10 900

2750

3100

4600

5540

84.3

85.0

86.1

82.9

84.8

80.6

49.1

33.1

36.4

43.6

50.0

45.2

Waxes

0.83

n.det.

0.85

0.95

0.93

30

28

30

28

Conditions: 0.02 mmol Ni; 100 eq. MAO; 20 ml toluene; 30 bar ethylene; Tꢁ50 8C; tꢁ2 h.

The results described here point to a chelate control of

the reaction which brings to a loss in catalyst activity

and selectivity on raising the flexibility of the ligand

backbone: a continuous decrease in selectivity towards

linear products is observed passing from cyclopentyli-

dene (entry 2 Table 9: 88%) to cyclohexylidene (entry 4

Table 9: 84%) or to cycloheptylidene (entry 5 Table 8:

71%). The catalytic results seem to point out to the

formation, in the case of more flexible rings, of more

stable and catalytically inactive complexes. Blocking the

catalyst flexibility of the cyclohexylidene backbone by a

t-butyl group has only a minor beneficial effect on

catalyst activity but does not modify dramatically the

catalyst selectivity (comparison of entries 4 and 6, Table

9).

A first remark concerns the catalyst activity and

confirms an observation previously pointed out for

palladium catalysts: comparing activities in entries 1

and 2, as well as in 3 and 4 (Table 10), a drop in TOF is

observed for complexes with phosphino ketoimines

bearing the sterically crowded diisopropyl group.

In analogy with results obtained with cationic palla-

dium complexes, comparison of entry 1 with entry 3 and

of entry 2 with entry 4 shows a drop in catalytic activity

consequent to backbone enlargement from cyclopenty-

lidene to cyclohexylidene. The highest activity is reached

for complex 11 (entry 1, Table 10) which also permits

the obtainment of highly linear (84.3%) terminal olefins

(49%) with high oligomerisation grade (C_max

Using cycloheptylidene [28, entry 6] or ‘‘blocked’’

ꢁ30).

/

cyclohexylidene backbone [25, entry 5] has no dramatic

influence neither on TOF nor on selectivities or on C_max.

2.7. Ethylene oligomerisation with nickel dibromide

complexes activated with MAO

Unexpectedly, the use of complex 31 bearing the open

chain heptylidene brings to the formation of waxes

(Table 10, entry 7), in contrast with its palladium

analogue which is sparingly active as oligomerisation

catalyst (Table 9, entry 7).

In order to check the potentiality of the a-diphenyl-

phosphino-ketoimine ligands also in the nickel(II)

catalysed homogeneous ethylene oligomerisation, the

P^ﬄN nickel dibromide complexes have been used as

catalysts with MAO as activating agent. Results are

collected in Table 10. All systems tested show much

higher activity compared to their analogous palladium

catalysts.

2.8. Oligomerisation of higher oleﬁns

The activity of the cationic palladium complexes was

also tested in the oligomerisation of higher olefins by

160

W. Keim et al. / Journal of Organometallic Chemistry 662 (2002) 150Á171

/

Table 11

Oligomerisation of propene with cationic palladium(II) complexes

a

Linearity (%)

Entry

Complex

Ligand

TOF (h^ꢂ1

)

C_max

1

2

3

4

5

6

7

8

10

13

16

19

22

24

27

30

dppCyPentMA

dppCyPentPA

dppCyHexMA

dppCyHexPA

dppCyHexMOA

dpptBuCyHexPA

dppCyHeptPA

dppHeptPA

75.1

37.8

22.8

3.4

43.4

55.5

33.6

44.1

42.5

45.7

18

15

12

9

22.3

11.1

5.4

12

9

36.8

b

Á/

1.4

Conditions: 0.05 mmol Pd; 20 ml CH₂Cl₂; 0.2 mol propene; Tꢁ70 8C; tꢁ16 h.

In the C₆-fraction.

a

b

Not determined because of the low conversion.

Table 12

1-Butene-oligomerisation with cationic palladium(II) complexes

a

Entry

Complex

Ligand

TOF (h^ꢂ1

)

Linearity

C₈%

C_max

C₁₂%

C₁₆%

1

2

3

10

13

16

dppCyPentMA

dppCyPentPA

dppCyHexMA

2.5

12.9

1.1

34.8

53.8

5.2

28.8

3.1

14.2

16

12

b

Á/

0.05 mmol Pd; 20 ml CH₂Cl₂; 0.1 mol 1-butene; Tꢁ70 8C; tꢁ16 h.

In the C_x-fraction (determined after hydrogenation).

a

b

Not determined because of the low conversion.

conducting batch tests under the conditions optimised

for the ethylene oligomerisation. The reaction time was

prolonged to 16 h because of the lower activity of the

substrates. The oligomerisation of propene was carried

out in dichloromethane at 70 8C. The results are

collected in Table 11.

atoms are obtained. The reaction solution does not

show signs of decomposition through Pd(0) formation.

Reducing the crowding on the imine substituent (entry

1) or using the more flexible cyclohexylidene backbone

(entry 3) dos not bring a beneficial effect on the catalytic

activity.

Complexes 10 and 13 that embody a cyclopentylidene

backbone, are more active then their homologues based

on a cyclohexylidene 16 and 19 or cycloheptylidene 27

structure. Complex 22 bearing the o-methoxy substi-

tuted ligand shows a scarce oligomerisation grade

combined with a moderate activity. A drop in catalytic

activity is shown by complexes 13 and 19 compared to

complexes 10 and 16, as a result of a higher steric

hindrance on palladium. The importance of a certain

backbone rigidity in the chelate control is evidenced by

entry 8: complex 30 is practically inactive in the propene

oligomerisation. It is interesting to note again how

reducing the ligand backbone flexibility by the t-butyl

group in complex 24 has the effect of raising the catalyst

activity (comparison of entry 6 with entry 4).

The most active complexes in the propene oligomer-

isation, 10, 13 and 16, have been tested in the 1-butene

oligomerisation. Results have been collected in Table 12.

It is evident, by comparing TOFs of Table 12 with those

of Table 11, that the catalytic activity is lowered. The

sterically hindered dppCyPentPA complex 13 shows in

this case the highest TOF (entry 2). Products up to 16 C-

Surprisingly, the fraction of linear products is rela-

tively high, in particular in the trimer and tetramer

fraction. The formation of linear dimers can be deduced

directly from the insertion mechanism, but for the

formation of linear trimers a palladium-alkyl isomerisa-

tion must first occur. Fig. 9 represents a possible

reaction pathway for the formation of butene linear

trimers.

A palladium-iso-alkyl compound can be formed by a

1,2- and subsequent 2,1- insertion of 1-butene in a

palladium hydride species. The palladium atom is

localised on the third carbon atom. If a b-elimination

takes place now, then 2-octene or 3-octene can be

formed. On the contrary, if a chain growth takes place

through another butene insertion, the formation of

branched trimers is inevitable. The formation of linear

trimers of 1-butene can only be explained in terms of

isomerisation of the palladium-iso-alkyl species by chain

walking to a stable n-octyl palladium intermediate

before the necessary 2,1-insertion of the third butene

takes place [34].

W. Keim et al. / Journal of Organometallic Chemistry 662 (2002) 150Á

/

171

161

(dme)NiBr₂(97%) were purchased from Aldrich; tetra-

methyltin was purchased from Fluka; P-chlorodiphe-

nylphosphine (95%) was purchased from Strem.

Reagents were used as received.

Palladium complexes (cod)PdCl₂[36], [(cod)-

Pd(CH₃)Cl] [37] have been synthesised following litera-

ture procedures. Palladium chloride was furnished by

Degussa AG. MAO was purchased from WITCO as

10% toluene solution (6Á

/

8% MAO and 2Á4% trimethy-

/

laluminum), ethylene 2.8 (99.8% purity) was purchased

from Gerling, Holz & Co. Reagents were used as

received.

Gas-chromatograms were obtained on Siemens Syn-

chromat systems equipped with a 25 m SE 54-CS

column using nitrogen as carrier gas, or with a 100 m

Pona CB using helium as carrier gas. Yields of ethylene

oligomers were obtained with the use of the internal

standard method (nonane). In the GC analytic an FID

detector was used. Concerning the determination of

linearity and quantity of 1-hexene in the C₆-fraction,

after having removed high boiling products by flash

distillation at room temperature the separation of the

C₆-fraction was performed on a Siemens Sichromat 1-4

instrument equipped with a 50 m Pona-HP-FS column.

Turn over frequencies (TOF) was calculated as [mole

Fig. 9. Mechanism of formation of linear trimers of 1-butene with

cationic Pd (II) complexes. The ligand and the charge of the

intermediate species have been omitted for clarity.

3. Experimental

3.1. General procedures and techniques

All procedures were routinely performed under pure

dry Ar using standard Schlenk techniques. ¹H-,

¹³C{¹H}-, and ³¹P{¹H}-NMR spectra were recorded

on a Bruker DPX 300 NMR spectrometer at 293 K. ³¹P-

NMR chemical shifts relative to 85% phosphoric acid

are reported with positive values downfield from the

reference. IR spectra were recorded on a Nicolet 510 P

FT spectrometer. For secondary ion mass spectra

(SIMS), obtained on a Finnigan MAT 95 spectrometer,

the samples were prepared as dispersion in 3-nitroben-

zylalcohol (NBA), or in a mixture of 1,4-dithio-DL-

threitol, 1,4-dithioerythritol, sulfolane (DTT/DTE/Sul).

Mass spectra of vaporisable solids (P^ﬄN-ligands) have

consumed monomer/(mole catalyst ×

3.2. General procedure for the synthesis of ligands 1Á

3.2.1. General procedure A

/

time)].

/

8

The alkylidene anilines were obtained by condensa-

tion from a ketone and an aniline. The reaction was

driven to completion by azeotropic distillation of water.

A 250 ml round flask was added of 0.1 mol of

substituted aniline, 0.11 mol of ketone, 0.3 g (1.7 mmol)

of p-tolyl sulphonic acid and 200 ml of toluene as

stripping agent. The mixture was kept under vigorous

stirring and refluxed with a water extractor for at least 6

h, in most cases overnight, until no more water was

formed. Eventually, the major part of the solvent was

distilled at normal pressure and the residue on a Vigreux

column under reduced pressure. The alkylidene anilines

(mostly obtained as very viscous liquids) have been

been recorded on a Varian MAT 112 S (E.I.ꢁ

/

70 eV,

10^ꢂ6Torr). The attributions of the frag-

210 8C, 2ꢃ

/

mentation pattern have been assigned through compar-

ison of isotopic abundance of ions with those calculated

from isotopic abundance of elements. Elemental ana-

lyses were performed on a Carlo Erba 1106 CHN-

Analyser. Single crystal X-ray diffraction studies were

carried out on Nonius CAD4 instruments equipped with

serial scintillation counters and a Bruker-AXS SMART

diffractometer with an APEX CCD detector.

stored under argon at ꢂ30 8C.

/

Spectroscopic data for the obtained ketoimines have

been deposited as supplementary material.

3.3. Synthesis of a-(diphenylphosphino)-ketoimines

If not otherwise specified, all solvents were purified by

common laboratory techniques and distilled prior to use

under a stream of Ar; deionised water was repeatedly

degassed with a water pump under ultrasound stirring

and eventually saturated with Ar. Deuterated solvents

for NMR spectroscopy have been purchased from

Aldrich and kept under Ar [35]. 2,6-Dimethyl-aniline,

2,6-diisopropyl-aniline, o-anisidine, AgSbF₆(97%),

3.3.1. General procedure B

In a round flask, 10 mmol of substituted alkylidene

aniline are solubilised in 20 ml n-pentane and 5 ml Et₂O

or THF, cooled at ꢂ30 8C and kept under vigorous

/

stirring. An equivalent quantity of a solution of n-BuLi

in hexanes was added dropwise and the reaction mixture

warmed to 0 8C in about 2 h. Incipient precipitation is

162

W. Keim et al. / Journal of Organometallic Chemistry 662 (2002) 150Á171

/

dissolved with the addition of a few millilitres of THF.

The now yellow mixture is again cooled at ꢂ30 8C and

lisation from methanol. Anal. Found: C, 81.54; H, 8.10;

N, 3.35. Calc. for C₂₉H₃₄NP: C, 81.46; H, 8.02; N,

3.28%. The compound is subject to a r.t. imine to

/

at this temperature 1.0 equivalent of P-chlorodiphenyl-

phosphine is added dropwise over a 30’ time, so that the

incipient red colour has disappeared before the next

drop is added. When all reagents are mixed, the reaction

vessel is warmed to room temperature (r.t.) and kept

under overnight stirring. The yellow suspension is

1

enamine tautomer equilibrium ratio of about 4:1. H-

NMR (CDCl₃, 300 MHz): [ppm] dꢁ

1.10 (4*d, Jꢁ

6.9 Hz, 4*3H, CHⁱ₃^Pr), 1.51Á

CH₂), 2.65, 2.72, 3.29 (hept., Jꢁ

6.9 Hz, 2H, CH^iPr),

3.59 (m, 0.8H, PCH), 6.05 (d, Jꢁ5.7 Hz, 0.2H), 6.88Á

7.68 (m, 13H, H_arom); ¹³C{¹H}-NMR (CDCl₃, 75 MHz,

only data for the main isomer are given) [ppm]: dꢁ22.7,

22.9 (CH₃), 23.4 (d, J_C,P6.4 Hz, CH₂), 23.5, 23.6

(CH₃), 27.8, 28.2 (CH^iPr), 28.9 (d, J_C,P

10.1 Hz, CH₂),

31.9 (CH₂), 44.6 (d, J_C,P16.6 Hz, PCH), 122.7Á134.6

(CH_arom), 135.3Á138.6 (C_ipso), 147.6, 147.8 (NC_ipso),

180.2 (d, J_C,P

10.5 Hz, Cꢁ

N); ³¹P{¹H}-NMR (CDCl₃,

121 MHz): [ppm] dꢁ

6.65 (s, ca. 0.8P, Ph₂P^ﬄCꢁ

NAr), ꢂ NHAr); IR

30.45 (s, ca. 0.2P, Ph₂P^ﬄCꢀ

(KBr): [cm^ꢂ1] nꢁ

1677.1 (s, CꢁN); MS: m/z (I_rel.

%)ꢁ

427 (5) [M]^ꢀ, 412 (16) [MꢂCH₃]^ꢀ, 385 (30)

[Mꢀ1ꢂ

C₃H₇]^ꢀ, 242 (5) [Mꢂ

/

0.84, 1.05, 1.06,

/

/2.26 (m, 6H,

/

diluted with 20 ml of Et₂O and washed with 2ꢃ20 ml

/

water. The organic phase is separated and dried over

sodium sulphate. The solvent is eventually evaporated in

vacuo. In some of the syntheses the P^ﬄN ligand

precipitates as a yellow solid that is purified by washing

/

ꢁ

/

ꢁ

/

ꢁ

/

with n-pentane. In general, the obtained yellowÁ

oils are diluted with methanol, n-pentane or THF and

kept at ꢂ10 8C for crystallisation.

/orange

/

ꢁ

/

ꢂ

/

3.3.2. 2,6-Dimethyl-N-(2-diphenylphosphino-

cyclopentylidene)aniline; dppCyPentMA (1)

/

C₃H₇]^ꢀ, 384 (100) [Mꢂ

/

The synthesis of the ligand was performed following

general procedure B described above starting from 5.62

g (30.01 mmol) of substituted alkylidene aniline p-1, 19

ml of a 1.6 M n-BuLi-solution and 6.28 g (28.46 mmol)

ClPPh₂. Yield: 5.07 g (13.64 mmol, 48%) of an off-white

solid, obtained by crystallisation from MeOH. Anal.

Found: C, 80.91; H, 7.10; N, 3.82. Calc. for C₂₅H₂₆NP:

C, 80.84; H, 7.06; N, 3.77%. The compound is subject to

a r.t. imine to enamine tautomer equilibrium ratio of

PPh₂]^ꢀ, 226 (8) [CH₂CH₂CHPPh₂]^ꢀ, 201 (8)

[CH₂CNAr]^ꢀ, 183 (10) [CNAr]^ꢀ, 108 (6), 91 (7)

[C₇H₇]^ꢀ, 77 (5) [C₆H₅]^ꢀ, 43 (9) [C₃H₇]^ꢀ.

3.3.4. 2,6-Dimethyl-N-(2-diphenylphosphino-

cyclohexylidene)aniline; dppCyHexMA (3)

about 6:1. ¹H-NMR (CDCl₃, 300 MHz): [ppm] dꢁ

1.55Á2.25 (br m, 6H, CH₂), 1.81 (s, 3H, CH₃), 1.97 (s,

3H, CH₃), 3.56 (dt, J_H,H4.2 Hz, J_H,P7.8 Hz, 1H,

PCH), 6.74Á

7.65 (m, 13H, H_arom); ¹³C{¹H}-NMR

(CDCl₃, 75 MHz) [ppm]: dꢁ17.9, 18.0 (CH₃), 23.2 (d,

J_C,P6.6 Hz, CH₂), 29.0 (d, J_C,P9.4 Hz, CH₂), 31.7

(CH₂), 45.0 (d, J_C,P16.3 Hz, PCH), 122.4, 127.7Á

134.7 (CH_arom), 125.9, 125.7, 137.1Á138.5 (C_ipso),

150.0 (NC_ipso), 180.5 (d, J_C,PN);

10.5 Hz, Cꢁ

³¹P{¹H}-NMR (CDCl₃, 121 MHz): [ppm] dꢁ

6.61

(s, ca. 0.85P, Ph₂P^ﬄCꢁ

NAr), ꢂ30.27 (s, ca. 0.15P,

Ph₂P^ﬄCꢀNHAr); IR (KBr): [cm^ꢂ1] nꢁ

1676.6 (s, Cꢁ

N); MS: m/z (I_rel./%)ꢁ372 (10) [Mꢀ

1]^ꢀ, 371 (33)

[M]^ꢀ, 357 (20) [Mꢀ CH₃]^ꢀ, 356 (100) [MꢂCH₃]^ꢀ,

1ꢂ

199 (15), 186 (54) [MꢂPPh₂or PPh₂ꢀ

1]^ꢀ, 185 (66)

/

The synthesis of the ligand was performed following

general procedure B starting from 3.28 g (16.29 mmol)

substituted alkylidene aniline p-3, 10 ml of a 1.6 M n-

BuLi solution and 3.60 g (16.32 mmol) ClPPh₂. The

product precipitates as white solid, is filtered, washed

/

ꢁ

/

ꢁ

/

with n-pentane and crystallised from THFÁEt₂O. Yield:

/

ꢁ

/

ꢁ

/

3.86 g (10.01 mmol, 61%). Anal. Found: C, 80.95; H,

7.28; N, 3.61. Calc. for C₂₆H₂₈NP: C, 81.01; H, 7.32; N,

ꢁ

/

1

3.63%. H-NMR (CDCl₃, 300 MHz): [ppm] dꢁ

/

1.45Á

/

ꢁ

/

2.10 (m, 7H, CH₂), 1.47 (s, 3H, CH₃), 1.78 (s, 3H, CH₃),

2.24Á2.37 (m, 1H, CH₂), 3.62 (dt, J_H,H5.4 Hz, J_H,P

11.4 Hz, 1H, PCH), 6.69Á7.68 (m, 13H, H_arom).

¹³C{¹H}-NMR (CDCl₃, 75 MHz): [ppm] dꢁ

17.7, 18.1

(CH₃), 23.8 (d, J_C,P8.7 Hz, CH₂), 27.8 (CH₂), 30.7 (d,

J_C,P3.5 Hz, CH₂), 31.1 (d, J_C,P11.1 Hz, CH₂), 47.3

(d, J_C,P

134.2 (CH_arom), 126.1 (MeC_ipso), 137.0 (d, J_C,P

Hz, PC_ipso), 137.8 (d, J_C,P

(NC_ipso), 173.8 (d, J_C,P

9.9 Hz, Cꢁ

(CDCl₃, 121 MHz): [ppm] dꢁ 12.78 (s); IR (KBr):

[cm^ꢂ1] nꢁ

1653.0 (s, CꢁN); MS: m/z (I_rel./%)ꢁ386 (15)

[Mꢀ 1ꢂ

1]^ꢀ, 385 (47) [M]^ꢀ, 371 (24) [Mꢀ CH₃]^ꢀ, 370

(100) [Mꢂ

CH₃]^ꢀ, 277 (18), 276 (46), 200 (29) [Mꢂ

PPh₂]^ꢀ, 199 (37), 185 (22) [PPh₂, MꢂPPh_2ꢂCH₃]^ꢀ,

/

ꢂ

/

ꢁ

/

ꢁ

/

ꢁ

/

ꢁ

/

ꢁ

/

[PPh₂]^ꢀ,184 (33), 183 (35), 144 (18), 109 (18), 108 (32),

105 (26) [C₈H₉]^ꢀ, 91 (15) [C₇H₇]^ꢀ, 79 (34), 77 (33)

[C₆H₅]^ꢀ.

ꢁ

/

11.9 Hz, PCH), 122.3, 127.5, 127.6, 128.2Á

/

ꢁ/11.8

ꢁ

/

16.0 Hz, PC_ipso), 148.2

ꢁ

/

N); ³¹P{¹H}-NMR

/

ꢂ

/

3.3.3. 2,6-Diisopropyl-N-(2-diphenylphosphino-

cyclopentylidene)aniline; dppCyPentPA (2)

/

The synthesis of the ligand was performed following

general procedure B starting from 10.22 g (41.99 mmol)

substituted alkylidene aniline p-2, 26.0 ml of a 1.6 M n-

BuLi solution and 9.00 g (40.79 mmol) ClPPh₂. Suitable

crystals for X-ray diffraction analysis have been ob-

tained by precipitation from MeOH. Yield: 8.37 g (19.58

mmol, 48%) of colourless crystals obtained by crystal-

/

183 (30), 172 (15) [Mꢂ

/

PPh_2ꢂC₂H₄]^ꢀ, 158 (23) [Mꢂ

/

PPh_2ꢂC₃H₆]^ꢀ, 145 (21), 108 (15), 105 (25) [C₈H₉]^ꢀ,

79 (23), 77 (27) [C₆H₅]^ꢀ, 41 (26) [C₃H₅]^ꢀ, 27 (16)

[C₂H₃]^ꢀ.

W. Keim et al. / Journal of Organometallic Chemistry 662 (2002) 150Á

/

171

163

3.3.5. 2,6-Diisopropyl-N-(2-diphenylphosphino-

cyclohexylidene)aniline; dppCyHexPA (4)

0.8P, Ph₂P^ﬄCꢁ

NHAr); IR (KBr): [cm^ꢂ1] nꢁ

m/z (I_rel./%)ꢁ388 (9) [Mꢀ

[Mꢀ1ꢂ

OCH₃]^ꢀ, 356 (100) [Mꢂ

202 (8) [Mꢂ

/

NAr), ꢂ

/

18.70 (s, ca. 0.2P, Ph₂P^ﬄCꢀ

/

1660.6 (s, Cꢁ

/

N); MS:

The synthesis of the ligand was performed following

general procedure B starting from 5.74 g (22.28 mmol)

substituted alkylidene aniline p-4, 14.5 ml of a 1.6 M n-

BuLi-solution and 4.90 g (22.21 mmol) ClPPh₂. The

addition of n-pentane to the yellow crude caused the

product precipitation. Suitable crystals for X-ray dif-

fraction analysis have been obtained by precipitation

/

1]^ꢀ, 387 (31) [M]^ꢀ, 357 (24)

/

OCH₃]^ꢀ, 319 (20),

/

PPh₂]^ꢀ, 185 (7) [PPh₂]^ꢀ, 183 (13), 160 (10)

[CH₂CHCNAr]^ꢀ, 133 (8) [CNAr]^ꢀ, 108 (10), 77 (15)

[C₆H₅]^ꢀ, 44 (15), 31 (18) [OCH₃]^ꢀ.

3.3.7. 2,6-Diisopropyl-N-(2-diphenylphosphino-4-^tbutyl-

cyclohexylidene)aniline; dpptBuCyHexPA (6)

from methanol at ꢂ20 8C. Yield: 6.18 g (13.99 mmol,

/

63%) of colourless powder or crystals. Anal. Found: C,

81.68; H, 8.27; N, 3.20. Calc. for C₃₀H₃₆NP: C, 81.60;

The synthesis of the ligand was performed following

general procedure B described above starting from 4.36

g (13.90 mmol) substituted alkylidene aniline p-6, 8.7 ml

of a 1.6 M n-BuLi-solution and 3.05 g (13,82 mmol)

ClPPh₂. The yellow raw product was treated with n-

1

H, 8.22; N, 3.17%. H-NMR (CDCl₃, 300 MHz): [ppm]

dꢁ

1.42Á

CH^iPr), 2.29Á

1H, CH^iPr), 3.59 (dt, J_H,H

PCH), 6.84Á

7.68 (m, 13H, H_arom); ¹³C{¹H}-NMR

(CDCl₃, 75 MHz): [ppm] dꢁ23.1, 23.3, 23.5, 23.6

(CH₃), 23.9 (d, J_C,P8.7 Hz, CH₂), 27.2 (CH₂), 27.4,

27.5 (CH^iPr), 30.7 (d, J_C,P

10.7 Hz, CH₂), 31.1 (d,

J_C,P2.8 Hz, CH₂), 47.0 (d, J_C,P12.1 Hz, PCH),

122.5Á

134.3 (CH_arom), 136.6, 136.7 (ⁱPrC_ipso), 137.2 (d,

J_C,P11.8 Hz, PC_ipso), 138.0 (d, J_C,P16.5 Hz, PC_ipso),

145.4 (NC_ipso), 173.1 (d, J_C,PN);

10.3 Hz, Cꢁ

³¹P{¹H}-NMR (CDCl₃, 121 MHz): [ppm] dꢁ

12.42

(s); IR (KBr): [cm^ꢂ1] nꢁ

1650.8 (s, CꢁN); MS: m/z

(I_rel./%)ꢁ

441 (5) [M]^ꢀ, 426 (7) [MꢂCH₃]^ꢀ, 399 (29)

[Mꢀ1ꢂ

C₃H₇]^ꢀ, 398 (100) [MꢂC₃H₇]^ꢀ, 256 (9) [Mꢂ

PPh₂]^ꢀ, 240 (19) [(CH₂)₃CHPPh₂]^ꢀ, 212 (11)

/

0.79, 0.84, 0.87, 1.00 (4*d, Jꢁ

2.02 (m, 7H, CH₂), 2.27 (hept., Jꢁ

2.41 (m, 1H, CH₂), 2.47 (hept., Jꢁ

6.3 Hz, J_H,P11.4 Hz, 1H,

/

6.9 Hz, 4*3H, CHⁱ₃^Pr),

/

/6.9 Hz, 1H,

/

6.9 Hz,

pentane and kept at ꢂ20 8C in order to induce crystal-

/

ꢁ

/

ꢁ

/

lisation. Yield: 3.56 g (7.15 mmol, 52% of the theory) of

colourless powder. Anal. Found: C, 82.10; H, 8.97; N,

2.88. Calc. for C₃₄H₄₄NP: C, 82.05; H, 8.91; N, 2.81%.

Being the compound obtained as a mixture of diaster-

eoisomers, an assignment of the NMR signals can only

/

ꢁ

/

ꢁ

/

ꢁ

/

ꢁ

/

tentatively be given. ¹H-NMR (CDCl₃, 300 MHz):

t

/

[ppm] dꢁ

(4*d, Jꢁ

2.80Á2.92 (m, 1H), 3.19Á

0.5H), 6.87Á

7.83 (m, 13H, H_arom); ¹³C{¹H}-NMR

/

0.65, 0.68 (s, 9H, Bu), 0.53, 0.88, 1.08, 1.11

ꢁ

/

ꢁ

/

6.9 Hz, 4*3H, CHⁱ₃^Pr), 1.15Á

3.33 (m, 0.5H), 3.90 (br m,

/2.50 (m, 8H),

ꢁ

/

ꢂ

/

(CDCl₃, 75 MHz): [ppm] dꢁ22.8, 23.3, 23.3, 23.4,

/

23.5, 23.5, 23.6 (CHⁱ₃^Pr), 27.2, 27.4 (CH₃^tBu), 27.4 (CH₂),

27.5, 27.7 (CH^iPr), 28.3, 29.2 (d), 31.6 (d), 31.8, 32.2

/

(CH₂), 34.7, 35.6 (CMe₃), 41.6 (d, J_C,P

CH^tBu), 45.8 (d, J_C,P8.5 Hz, CH^tBu), 47.4 (d,

J_C,P15.0 Hz, PCH), 48.1 (d, J_C,P7.8 Hz, PCH),

122.4Á134.7 (CH_arom), 136.0Á139.2 (C_ipso), 145.5, 145.6

(NC_ipso), 172.5 (d, J_C,PN), 174.6 (d, J_C,P

6.6 Hz, Cꢁ

13.7 Hz, Cꢁ

N); ³¹P{¹H}-NMR (CDCl₃, 121 MHz):

[ppm] dꢁ 8.35 (s, ca. 0.7P), ꢂ15.46 (s, ca. 0.3P); IR

(KBr): [cm^ꢂ1] nꢁ

1658.3 (s, CꢁN); MS: m/z (I_rel./%)ꢁ

498 (1) [Mꢀ

1]^ꢀ, 497 (4) [M]^ꢀ, 482 (5) [MꢂCH₃]^ꢀ, 455

(31) [Mꢀ1ꢂ

C₃H₇]^ꢀ, 454 (100) [MꢂC₃H₇]^ꢀ, 312 (10)

[Mꢂ

PPh₂]^ꢀ, 296 (10), 254 (10), 214 (23)

ꢁ/8.8 Hz,

[CH₂CHPPh₂]^ꢀ, 186 (10) [398ꢂ

/

212]^ꢀ, 185 (9)

ꢁ

/

[PPh₂]^ꢀ, 183 (14), 108 (9), 91 (9) [C₇H₇]^ꢀ, 77 (7)

[C₆H₅]^ꢀ, 44 (18), 43 (20) [C₃H₇]^ꢀ, 41 (15).

ꢁ

/

ꢁ

/

ꢁ

/

ꢁ

/

3.3.6. 2-Methoxy-N-(2-diphenylphosphino-

/

cyclohexylidene)aniline; dppCyHexMOA (5)

/

ꢂ

/

The synthesis of the ligand was performed following

general procedure B described above starting from 1.00

g (4.91 mmol) substituted alkylidene aniline p-5, 3.5 ml

of a 1.6 M n-BuLi-solution and 1.10 g (4.99 mmol)

ClPPh₂. The solid raw product was washed with n-

pentane and dried in vacuo. Yield: 0.80 g (2.06 mmol,

42% of the theory) colourless powder. The compound is

probably subject to a r.t. imine to enamine tautomer

equilibrium ratio of about 3.5:1. Anal. Found: C, 77.55;

H, 6.81; N, 3.71. Calc. for C₂₅H₂₆NOP: C, 77.50; H,

6.76; N, 3.62%. ¹H-NMR (CDCl₃, 300 MHz): [ppm]

/

[CH₂CHCNAr]^ꢀ, 201 (10), 186 (15), 185 (14) [PPh₂]^ꢀ,

183 (17), 108 (12), 91 (12) [C₇H₇]^ꢀ, 77 (11) [C₆H₅]^ꢀ, 57

(37) [C₄H₉]^ꢀ, 43 (42) [C₃H₇]^ꢀ, 41 (52) [C₃H₅]^ꢀ, 29 (27)

[C₂H₅]^ꢀ.

3.3.8. 2,6-Diisopropyl-N-(2-diphenylphosphino-

cycloheptylidene)aniline; dppCyHeptPA (7)

dꢁ

3.69 (2*s, 3H, OCH₃), 6.10Á

¹³C{¹H}-NMR (CDCl₃, 75 MHz, only data for the

main isomer are given) [ppm]: dꢁ23.4 (d, J_C,P8.7 Hz,

CH₂), 27.9 (CH₂), 30.8 (d, J_C,P12.6 Hz, CH₂), 31.2 (d,

J_C,P3.9 Hz, CH₂), 48.3 (d, J_C,P13.0 Hz, PCH), 55.4,

55.5 (OCH₃), 110.3Á139.6 (CH_arom

(NC_ipso), 175.7 (d, J_C,P

9.3 Hz, Cꢁ

NMR (CDCl₃, 121 MHz): [ppm] dꢁ

/

1.48Á

/

2.35 (br m, 8H, CH₂), 3.54 (m, 1H PCH), 3.59,

The synthesis of the ligand was performed following

general procedure B starting from 5.08 g (18.71 mmol)

substituted alkylidene aniline p-7, 11.4 ml of a 1.6 M n-

BuLi-solution and 4.05 g (18.36 mmol) ClPPh₂. The

product precipitates as a solid and is recrystallised from

n-pentane. Yield: 5.50 g (12.07 mmol, 66%) of colourless

powder. Anal. Found: C, 81.64; H, 8.40; N, 3.00. Calc.

/

7.58 (m, 14H, H_arom);

/

ꢁ

/

ꢁ

/

ꢁ

/

ꢁ

/

,

C_ipso), 149.1

N); ³¹P{¹H}-

1

ꢁ

/

for C₃₁H₃₈NP: C, 81.72; H, 8.41; N, 3.07%. H-NMR

/

ꢂ

/

10.17 (s, ca.

(CDCl₃, 300 MHz): [ppm] dꢁ0.69, 0.85, 0.90, 1.01

/

164

W. Keim et al. / Journal of Organometallic Chemistry 662 (2002) 150Á171

/

(4*d, Jꢁ

CH₂), 2.13Á

1H, CH^iPr), 2.51 (hept., Jꢁ

1H, PCH), 6.86Á

7.65 (m, 13H, H_arom); ¹³C{¹H}-NMR

(CDCl₃, 75 MHz): [ppm] dꢁ22.6, 22.8, 23.8, 23.9

(CHⁱ₃^Pr), 24.4 (CH₂), 27.5, 27.7 (CH^iPr), 28.9 (CH₂),

29.5 (d, J_C,P9.5 Hz, CH₂), 30.4 (d, J_C,P13.6 Hz,

CH₂), 34.0 (CH₂), 47.2 (d, J_C,P9.8 Hz, PCH), 122.7Á

134.4 (CH_arom), 135.5, 136.6 (ⁱPrC_ipso), 138.1 (d, J_C,P

14.4 Hz, PC_ipso), 138.5 (d, J_C,P17.4 Hz, PC_ipso), 145.5

(NC_ipso), 175.9 (d, J_C,P

8.7 Hz, Cꢁ

N); ³¹P{¹H}-NMR

(CDCl₃, 121 MHz): [ppm] dꢁ 10.91(s); IR (KBr):

[cm^ꢂ1] nꢁ

1637.2 (s, CꢁN); MS: m/z (I_rel./%)ꢁ456 (1)

[Mꢀ 1ꢂ

1]^ꢀ, 455 (5) [M]^ꢀ, 413 (26) [Mꢀ C₃H₇]^ꢀ, 412

(100) [Mꢂ

C₃H₇]^ꢀ, 378 (4) [MꢂPh]^ꢀ, 270 (26) [Mꢂ

PPh₂]^ꢀ, 269 (26) [Mꢂ 1]^ꢀ, 254 (13)

CNArꢀ

[(CH₂)₄CHPPh₂]^ꢀ, 226 (20) [(CH₂)₂CHPPh₂]^ꢀ, 186

/

6.9 Hz, 4*3H, CHⁱ₃^Pr), 1.23Á

2.20 (m, 2H, CH₂), 2.20 (hept., Jꢁ

6.9 Hz, 1H, CH^iPr), 3.71 (m,

/

1.80 (m, 8H,

3.4. Synthesis of neutral palladium complexes

/

/6.9 Hz,

3.4.1. General procedure C

/

To a solution of 1.00 mmol palladium precursor in 5

ml CH₂Cl₂kept under vigorous stirring, a solution of

1.00 equivalent of ligand in 7 ml of the same solvent is

added dropwise at r.t. The solution is stirred for 30 min,

then the solvent is reduced to 2 ml in vacuo and the

product is precipitated by adding 20 ml n-pentane. The

/

ꢁ

/

ꢁ

/

ꢁ

/

ꢁ

/

solid is filtered, washed with 3ꢃ10 ml pentane and

/

ꢁ

/

dried. Complexes are obtained in nearly quantitative

yields.

ꢁ

/

ꢂ

/

3.4.2. [{2,6-Dimethyl-N-(2-diphenylphosphino-

/

cyclopentylidene)aniline-k²-P,N} (chloro)(methyl)-

palladium(II)]; (dppCyPentMA)Pd(CH₃)Cl (9)

Scale: 262.3 mg (0,989 mmol) (cod)Pd(CH₃)Cl; 367.5

mg (0.989 mmol) (1); Yield: 496.6 mg (0.94 mmol, 95%)

white solid. Anal. Found: C, 59.04; H, 5.50; N, 2.55.

Calc. for C₂₆H₂₉ClNPPd: C, 59.11; H, 5.53; N, 2.65%.

/

(17) [Mꢂ

C₃H_7ꢂ(CH₂)₂CHPPh₂]^ꢀ, 183 (12), 108 (9),

/

91 (11) [C₇H₇]^ꢀ, 43 (20) [C₃H₇]^ꢀ, 41 (18) [C₃H₅]^ꢀ.

¹H-NMR (CDCl₃, 300 MHz): [ppm] dꢁ

J_H,P3.3 Hz, 3H, PdCH₃), 1.51Á1.68 (m, 2H, CH₂),

1.88Á2.09 (m, 4H, CH₂), 2.11 (s, 3H, CH₃), 2.13 (s, 3H,

CH₃), 4.14 (m, 1H, PCH), 6.88Á7.94 (m, 13H, H_arom);

¹³C{¹H}-NMR (CDCl₃, 75 MHz): [ppm] dꢁ

3.5

(PdCH₃), 18.4, 19.0 (CH₃), 25.9 (d, J_C,P7.1 Hz,

CH₂), 26.8 (d, J_C,P8.4 Hz, CH₂), 30.1 (d, J_C,P6.6

Hz, CH₂), 56.6 (d, J_C,P26.1 Hz, PCH), 125.6Á136.6

(CH_arom, C_ipso), 146.1 (NC_ipso), 191.3 (d, J_C,P10.4 Hz,

Cꢁ

N); ³¹P{¹H}-NMR (CDCl₃, 121 MHz): [ppm] dꢁ

43.17 (s); IR (KBr): [cm^ꢂ1] nꢁ

1645.2 (s, CꢁN); SIMS

(NBA), cation: m/z (I_rel.(%))ꢁ514 (15)

[(P^ﬄN)Pd(Cl)]^ꢀ, 492 (42) [(P^ﬄN)Pd(CH₃)]^ꢀ, 477 (9)

[(P^ﬄN)Pd]^ꢀ, 291 (7) [PdPPh₂]^ꢀ, 186 (100) [(P^ﬄN)ꢀ

PPh₂or PPh₂ꢀ

1]^ꢀ; SIMS (NBA), anion: m/z (I_rel.

(%))ꢁ528 (100) [Mꢂ

1]^ꢂ, 341 (9) [Clꢀ2NBA]^ꢂ, 188

(49) [Clꢀ

NBA]^ꢂ.

/

0.55 (d,

ꢁ

/

3.3.9. 2,6-Diisopropyl-N-(1-n-propyl-2-

/

diphenylphosphino-butylidene)aniline; dppHeptPA (8)

The synthesis of the ligand was performed following

general procedure B starting from 5.08 g (18.57 mmol)

substituted alkylidene aniline p-8, 11.4 ml of a 1.6 M n-

BuLi-solution and 4.05 g (18.36 mmol) ClPPh₂. Recrys-

tallised from n-pentane. Yield: 5.19 g (11.33 mmol, 62%)

colourless powder. Anal. Found: C, 81.46; H, 8.85; N,

3.12. Calc. for C₃₁H₄₀NP: C, 81.36; H, 8.81; N, 3.06%.

/

ꢂ

/

ꢁ

/

ꢁ

/

ꢁ

/

ꢁ

/

ꢁ

/

¹H-NMR (CDCl₃, 300 MHz): [ppm] dꢁ

Hz, 3H, CH₃), 0.83, 0.88 (2*d, Jꢁ6.9 Hz, 2*3H,

CHⁱ₃^Pr), 0.95 (t, Jꢁ

7.2 Hz, 3H, CH₃), 1.00, 1.01 (2*d,

Jꢁ 2.15 (m, 6H, CH₂), 2.37

6.9 Hz, 2*3H, CHⁱ₃^Pr), 1.25Á

(hept., Jꢁ 6.9 Hz,

6.9 Hz, 1H, CH^iPr), 2.61 (hept., Jꢁ

1H, CH^iPr), 3.45 (m, 1H, PCH), 6.87Á

7.64 (m, 13H,

_arom); ¹³C{¹H}-NMR (CDCl₃, 75 MHz): [ppm] dꢁ

/

0.69 (t, Jꢁ7.2

/

H

/

3.4.3. [{2,6-Diisopropyl-N-(2-diphenylphosphino-

cyclopentylidene)aniline-k²-P,N} (chloro)(methyl)-

palladium(II)]; (dppCyPentPA)Pd(CH₃)Cl (12)

Scale: 527.5 mg (1.990 mmol) (cod)Pd(CH₃)Cl; 850.9

mg (1.990 mmol) (2); Yield: 1128.2 mg (1.930 mmol,

97%) white solid. Anal. Found: C, 61.78; H, 6.40; N,

2.45. Calc. for C₃₀H₃₇ClNPPd: C, 61.65; H, 6.38; N,

2.40%.

13.9 (d, J_C,P

ꢁ8.8 Hz, CH₃), 14.6 (CH₃), 19.3 (CH₂),

/

22.6, 22.7, 23.6, 24.1 (CHⁱ₃^Pr), 23.9 (CH₂), 27.4, 27.8

(CH^iPr), 37.2 (d, J_C,P

15.0 Hz, PCH), 122.5Á

(ⁱPrC_ipso), 137.6 (d, J_C,P

J_C,P17.4 Hz, PC_ipso), 145.7 (NC_ipso), 174.4 (d, J_C,P

8.7 Hz, Cꢁ

N); ³¹P{¹H}-NMR (CDCl₃, 121 MHz):

[ppm] dꢁ 1634.0 (s,

2.95 (s); IR (KBr): [cm^ꢂ1] nꢁ

CꢁN); MS: m/z (I_rel./%)ꢁ458 (1) [Mꢀ

1]^ꢀ, 457 (5)

[M]^ꢀ, 415 (8) [Mꢀ C₃H₇]^ꢀ, 414 (37) [MꢂC₃H₇]^ꢀ,

1ꢂ

272 (19) [Mꢂ

PPh₂]^ꢀ, 230 (100) [H₃C(CH₂)₂CNAr]^ꢀ,

228 (37) [H₃CCH₂CHPPh₂ꢀ 187 (14)

1]^ꢀ,

C₃H₇]^ꢀ, 185 (10) [PPh₂]^ꢀ, 91 (18)

ꢁ

/

3.0 Hz, CH₂), 47.8 (d, J_C,P

133.8 (CH_arom), 136.0, 136.2

15.5 Hz, PC_ipso), 137.7 (d,

ꢁ

/

ꢁ

/

ꢁ

/

ꢁ

/

¹H-NMR (CDCl₃, 300 MHz): [ppm] dꢁ

J_H,P3.3 Hz, 3H, PdCH₃), 0.90, 1.03, 1.32, 1.44 (4*d,

Jꢁ 1.66 (m, 2H, CH₂),

6.9 Hz, 4*3H, CHⁱ₃^Pr), 1.54Á

1.88Á2.12 (m, 4H, CH₂), 2.94 (hept., Jꢁ6.9 Hz, 2H,

CH^iPr), 4.18 (m, 1H, PCH), 7.04Á

7.96 (m, 13H, H_arom);

¹³C{¹H}-NMR (CDCl₃, 75 MHz): [ppm] dꢁ

3.6 (d,

J_C,P

2.0 Hz, PdCH₃), 23.3, 23.9, 24.0, 24.8 (CHⁱ₃^Pr),

25.7 (d, J_C,P7.1 Hz, CH₂), 26.9 (d, J_C,P8.2 Hz,

CH₂), 28.1, 28.5 (CH^iPr), 31.2 (d, J_C,P

6.5 Hz, CH₂),

56.2 (d, J_C,P25.5 Hz, PCH), 123.3Á138.7 (CH_arom

/0.57 (d,

/

ꢂ

/

ꢁ

/

ꢂ

/

[H₃C(CH₂)₂CNArꢀ

/

ꢁ

/

[C₇H₇]^ꢀ, 55 (11) [C₄H₇]^ꢀ, 43 (40) [C₃H₇]^ꢀ, 41 (20)

[C₃H₅]^ꢀ.

ꢁ

/

ꢁ

/

ꢁ

/

ꢁ

/

,

W. Keim et al. / Journal of Organometallic Chemistry 662 (2002) 150Á

/

171

165

C_ipso), 143.4 (NC_ipso), 191.7 (d, J_C,P

³¹P{¹H}-NMR (CDCl₃, 121 MHz): [ppm] dꢁ

IR (KBr): [cm^ꢂ1] nꢁ

1648.8 (s, CꢁN); SIMS (NBA),

cation: m/z (I_rel.(%))ꢁ

570 (27) [(P^ﬄN)Pd(Cl)]^ꢀ, 548

(30) [(P^ﬄN)Pd(CH₃)]^ꢀ, 533 (17) [(P^ﬄN)Pd]^ꢀ, 346 (63)

ꢁ

/

10.1 Hz, Cꢁ

/

N);

CH₂), 28.1, 28.5 (CH^iPr), 30.8 (d, J_C,P

33.7 (d, J_C,P

PCH), 123.0Á

181.7 (d, J_C,P

121 MHz): [ppm] dꢁ

1604.8 (s, CꢁN); SIMS (NBA), cation: m/z (I_rel.(%))ꢁ

584 (37) [(P^ﬄN)Pd(Cl)]^ꢀ, 562 (42) [(P^ﬄN)Pd(CH₃)]^ꢀ,

547 (20) [(P^ﬄN)Pd]^ꢀ, 398 (2) [(P^ﬄN)ꢀC₃H₇]^ꢀ, 360 (62)

[(CH₂)₄CHPPh₂Pd]^ꢀ, 291 (13) [PdPPh₂]^ꢀ, 256 (100)

[(P^ﬄN)ꢀPPh₂]^ꢀ, 254 (69) [(CH₂)₄CHPPh₂]^ꢀ, 240 (9)

[(CH₂)₃CHPPh₂]^ꢀ, 212 (12) [CH₂CHPPh₂]^ꢀ, 186 (5)

[(P^ﬄN)ꢀC₃H_7ꢂCH₂CHPPh₂]^ꢀ; SIMS (NBA), anion:

m/z (I_rel.(%))ꢁ598 (100) [Mꢂ

1]^ꢂ, 188 (25) [Clꢀ

NBA]^ꢂ.

ꢁ

/

4.2 Hz, CH₂),

/

42.70 (s);

ꢁ

/

6.2 Hz, CH₂), 53.6 (d, J_C,P

138.6 (CH_arom, C_ipso), 142.5 (NC_ipso),

7.5 Hz, Cꢁ

N); ³¹P{¹H}-NMR (CDCl₃,

49.78 (s); IR (KBr): [cm^ꢂ1] nꢁ

ꢁ

/

26.9 Hz,

/

ꢁ

/

[C₁₇H₂₂NPd]^ꢀ, 291 (11) [PdPPh₂]^ꢀ, 242 (100) [(P^ﬄN)ꢀ

/

PPh₂]^ꢀ, 240 (87) [C₁₇H₂₂N]^ꢀ, 238 (20), 226 (16)

[(CH₂)₂CHPPh₂]^ꢀ, 224 (11), 215 (10), 201 (8)

[CH₂CHNAr]^ꢀ, 198 (11) [CHPPh₂]^ꢀ, 183 (13)

/

[CNAr]^ꢀ; SIMS (NBA), anion: m/z (I_rel.(%))ꢁ

(100) [Mꢂ

1]^ꢂ, 341 (5) [Clꢀ

NBA]^ꢂ.

/

584

/

2NBA]^ꢂ, 188 (37) [Clꢀ

/

3.4.4. [{2,6-Dimethyl-N-(2-diphenylphosphino-

cyclohexylidene)aniline-k²-P,N}(chloro)(methyl)-

palladium(II)]; (dppCyHexMA)Pd(CH₃)Cl (15)

Scale: 290.0 mg (1.094 mmol) (cod)Pd(CH₃)Cl; 421.7

mg (1.094 mmol) (3); Yield: 581.7 mg (1.072 mmol, 98%)

white solid. Anal. Found: C, 59.70; H, 5.74; N, 2.55.

Calc. for C₂₇H₃₁ClNPPd: C, 59.79; H, 5.76; N, 2.58%.

3.4.6. [{2-Methoxy-N-(2-diphenylphosphino-

cyclohexylidene)aniline-k²-P,N}(chloro)(methyl)-

palladium(II)]; (dppCyHexMOA)Pd(CH₃)Cl (21)

Scale: 113.9 mg (0.430 mmol) (cod)Pd(CH₃)Cl; 166.3

mg (0.429 mmol) (5); yield: 221.5 mg (0.407 mmol, 95%)

white solid; Anal. Found: C, 57.40; H, 5.42; N, 2.63.

Calc. for C₂₆H₂₉ClNOPPd: C, 57.37; H, 5.37; N, 2.57%.

The product seems to be a mixture of diastereomers

or rotamers in the ratio 1:1.

¹H-NMR (CDCl₃, 300 MHz): [ppm] dꢁ

J_H,P2.7 Hz, 3H, PdCH₃), 1.20Á1.52 (m, 3H, CH₂),

1.62Á1.91 (m, 4H, CH₂), 1.94 (s, 3H, CH₃), 2.20 (s, 3H,

CH₃), 2.30Á2.38 (m, 1H, CH₂), 3.60 (m, 1H, PCH),

6.91Á

7.73 (m, 13H, H_arom); ¹³C{¹H}-NMR (CDCl₃, 75

MHz): [ppm] dꢁ 3.9 (PdCH₃), 18.3, 19.0 (CH₃), 26.0

(d, J_C,P7.5 Hz, CH₂), 26.1 (CH₂), 31.9 (d, J_C,P3.1

Hz, CH₂), 32.9 (d, J_C,P6.2 Hz, CH₂), 53.9 (d, J_C,P

135.4 (CH_arom, C_ipso), 145.2

7.5 Hz, Cꢁ

N); ³¹P{¹H}-

49.60 (s); IR

N); SIMS (NBA),

528 (16) [(P^ﬄN)Pd(Cl)]^ꢀ, 506

(23) [(P^ﬄN)Pd(CH₃)]^ꢀ, 491 (4) [(P^ﬄN)Pd]^ꢀ, 384 (2)

[(P^ﬄN)ꢂ1]^ꢀ, 306 (16), 291 (10) [PdPPh₂]^ꢀ, 214 (3), 200

(100) [(P^ﬄN)ꢀPPh₂]^ꢀ, 198 (12) [CHPPh₂]^ꢀ, 153 (26);

SIMS (NBA), anion: m/z (I_rel.(%))ꢁ542 (100) [Mꢂ

1]^ꢂ, 341 (4) [Clꢀ2NBA]^ꢂ, 188 (43) [ClꢀNBA]^ꢂ, 152

(9).

/

0.54 (d,

ꢁ

/

¹H-NMR (CDCl₃, 300 MHz): [ppm] dꢁ

(2*d, J_H,P2.7 Hz, 3H, PdCH₃), 1.33Á2.10 (br m, 7H,

CH₂), 2.50 (m, 1H, CH₂), 3.53 (m, 1H, PCH), 3.70, 3.80

(2*s, 3H, OCH₃), 6.71Á

7.76 (m, 14H, H_arom); ¹³C{¹H}-

NMR (CDCl₃, 75 MHz): [ppm] dꢁ 4.6, ꢂ4.6 (2*s,

PdCH₃), 25.6Á33.8 (CH₂), 53.5 (d, J_C,P28.2 Hz,

PCH), 54.0 (d, J_C,P28.6 Hz, PCH), 55.9, 56.2 (2*s,

OCH₃), 111.5Á136.3 (CH_arom, C_ipso), 149.9, 150.0

(NC_ipso), 183.0 (br, CꢁN), 183.8 (d, J_C,P6.9 Hz, Cꢁ

N); ³¹P{¹H}-NMR (CDCl₃, 121 MHz): [ppm] dꢁ

50.22

(s, 0.5P), 50.56 (s, 0.5P); IR (KBr): [cm^ꢂ1] nꢁ

1618.0

(m, CꢁN); SIMS (NBA), cation: m/z (I_rel.(%))ꢁ530

(15) [(P^ﬄN)Pd(Cl)]^ꢀ, 508 (43) [(P^ﬄN)Pd(CH₃)]^ꢀ, 493

(3) [(P^ﬄN)Pd]^ꢀ, 291 (5) [PdPPh₂]^ꢀ, 202 (100) [(P^ﬄN)ꢀ

PPh₂]^ꢀ, 183 (4), 133 (4) [CNAr]^ꢀ; SIMS (NBA), anion:

m/z (I_rel.(%))ꢁ544 (83) [Mꢂ

1]^ꢂ, 528 (5) [MꢂCH₃]^ꢂ,

341 (14) [Clꢀ

2NBA]^ꢂ, 188 (100) [ClꢀNBA]^ꢂ.

/0.55, 0.56

/

ꢂ

/

ꢁ

/

ꢁ

/

ꢁ

/

ꢁ

/

ꢁ

/

27.8 Hz, PCH), 125.4Á

/

ꢂ

/

(NC_ipso), 182.5 (d, J_C,P

ꢁ

/

ꢁ

/

NMR (CDCl₃, 121 MHz): [ppm] dꢁ

(KBr): [cm^ꢂ1] nꢁ

1615.3 (s, Cꢁ

cation: m/z (I_rel.(%))ꢁ

/

ꢁ

/

ꢁ

/

3.4.5. [{2,6-Diisopropyl-N-(2-diphenylphosphino-

hexylidene)aniline-k²-P,N}(chloro)(methyl)-

palladium(II)]; (dppCyHexPA)Pd(CH₃)Cl (18)

Scale: 224.6 mg (0.847 mmol) (cod)Pd(CH₃)Cl; 373.7

mg (0.846 mmol) (4); Yield: 479.8 mg (0.802 mmol, 95%)

white solid. Anal. Found: C, 62.34; H, 6.62; N, 2.41.

Calc. for C₃₁H₃₉ClNPPd: C, 62.21; H, 6.57; N, 2.34%.

/

3.4.7. [{2,6-Diisopropyl-N-(2-diphenylphosphino-4-tert-

butyl-cyclohexylidene)aniline-k²-P,N}(chloro)(methyl)-

palladium(II)]; (dpptBuCyHexPA)Pd(CH₃)Cl (23)

Scale: 401.2 mg (1.513 mmol) (cod)Pd(CH₃)Cl; 752.2

mg (1.511 mmol) (6); yield: 923.5 mg (1.411 mmol, 93%)

white solid. Anal. Found: C, 64.30; H, 7.27; N, 2.21.

Calc. for C₃₅H₄₇ClNPPd: C, 64.22; H, 7.24; N, 2.14%.

Being the compound obtained as a mixture of

diastereoisomers in the approximate ratio of 3:1, an

assignment of the NMR signals can only tentatively be

given.

¹H-NMR (CDCl₃, 300 MHz): [ppm] dꢁ

J_H,P2.7 Hz, 3H, PdCH₃), 0.97, 1.03 (2*d, Jꢁ

Hz, 2*3H, CHⁱ₃^Pr), 1.16Á

1.27 (m, 1H, CH₂), 1.27, 1.44

(2*d, Jꢁ 1.53 (br m, 2H,

6.9 Hz, 2*3H, CHⁱ₃^Pr), 1.32Á

CH₂), 1.68Á1.95 (m, 4H, CH₂), 2.41Á2.49 (m, 1H, CH₂),

2.67, 3.00 (2*hept., Jꢁ

6.9 Hz, 2*1H, CH^iPr), 3.60 (m,

1H, PCH), 7.05Á

7.79 (m, 13H, H_arom); ¹³C{¹H}-NMR

(CDCl₃, 75 MHz): [ppm] dꢁ 3.9 (PdCH₃), 23.6, 23.8,

24.0, 24.0 (CHⁱ₃^Pr), 25.0 (CH₂), 25.7 (d, J_C,P

7.1 Hz,

/

0.54 (d,

6.9

ꢁ

/

¹H-NMR (CDCl₃, 300 MHz): [ppm] dꢁ

(2*d, Jꢁ3.0 Hz, 3H, PdCH₃), 0.66, 0.68 (2*s, 9H,

CH^t₃^Bu), 0.96Á 6.9 Hz, 4*3H, CHⁱ₃^Pr),

1.46 (8*d, Jꢁ

/0.54, 0.55

/

ꢂ

/

ꢁ

/

166

W. Keim et al. / Journal of Organometallic Chemistry 662 (2002) 150Á171

/

1.04Á

CH₂), 2.64, 2.91 (2*hept., Jꢁ

3.63, 3.81 (2*m, 1H, PCH), 7.05Á

¹³C{¹H}-NMR [selected signals] (CDCl₃, 75 MHz):

3.9 (s, PdCH₃), 21.7 (CH₂), 23.5, 23.6,

23.7, 23.8, 23.9, 24.0, 24.7 (CHⁱ₃^Pr), 25.1 (d), 26.0 (CH₂),

26.7, 27.2 (CH^t₃^Bu), 28.1, 28.2, 28.5, 28.6 (CH^iPr), 31.6

(d), 31.8 (d), 33.1 (d) (CH₂), 32.5, 34.4 (CMe₃), 42.1 (d,

/

1.37 (br m, 2H, CH₂), 1.57Á

6.9 Hz, 2*1H, CH^iPr),

7.85 (m, 13H, H_arom);

/

2.85 (br m, 5H, CH,

3.4.9. [{2,6-Diisopropyl-N-(1-n-propyl-2-

diphenylphosphinobutylidene)aniline-k²-P,N}(chloro)-

(methyl)palladium(II)]; (dppHeptPA)Pd(CH₃)Cl

(29)

Scale: 477.2 mg (1.800 mmol) (cod)Pd(CH₃)Cl; 823.8

mg (1.800 mmol) (8); yield: 1070.7 mg (1.742 mmol,

97%) white solid. Anal. Found: C, 62.51; H, 7.04; N,

2.31. Calc. for C₃₂H₄₃ClNPPd: C, 62.54; H, 7.05; N,

2.28%.

/

[ppm] dꢁ

/

ꢂ

/

J_C,P

49.2 (d, J_C,P

PCH), 123.0Á

(NC_ipso), 181.9 (d, J_C,P

J_C,P

6.9 Hz, Cꢁ

N); ³¹P{¹H}-NMR (CDCl₃, 121

MHz): [ppm] dꢁ50.15 (s, ca. 0.75P), 52.09 (s, ca.

0.25P); IR (KBr): [cm^ꢂ1] nꢁ

1616.2 (s, CꢁN); SIMS

(NBA), cation: m/z (I_rel.(%))ꢁ640 (99)

[(P^ﬄN)Pd(Cl)]^ꢀ, 618 (73) [(P^ﬄN)Pd(CH₃)]^ꢀ, 603 (40)

[(P^ﬄN)Pd]^ꢀ, 416 (70) [310ꢀPd]^ꢀ, 312 (87) [(P^ﬄN)ꢀ

CNAr]^ꢀ, 308 (12), 291 (29)

ꢁ

/

4.9 Hz, CH^tBu), 47.4 (d, J_C,P

25.5 Hz, PCH), 53.1 (d, J_C,P

138.7 (CH_aromC_ipso), 142.4, 142.5

7.4 Hz, CꢁN), 184.3 (d,

ꢁ

/

5.9 Hz, CH^tBu),

¹H-NMR (CDCl₃, 300 MHz): [ppm] dꢁ

6.9 Hz, 3H, CHⁱ₃^Pr), 0.78 (d, J_H,P

2.4 Hz, 3H, PdCH₃),

0.71, 0.73 (2*t, Jꢁ7.2 Hz, 2*3H, CH₃), 1.01, 1.17, 1.35

(3*d, Jꢁ 2.08 (m, 6H,

6.9 Hz, 3*3H, CHⁱ₃^Pr), 1.40Á

CH₂), 2.16, 2.67 (2*hept. , Jꢁ

6.9 Hz, 2*1H, CH^iPr),

3.65 (m, 1H, PCH), 6.93Á7.95 (m, 13H, H_arom);

¹³C{¹H}-NMR (CDCl₃, 75 MHz): [ppm] dꢁ

4.5

(PdCH₃), 13.5 (d, J_C,P6.7 Hz, CH₃), 14.4 (CH₃),

19.8 (CH₂), 22.6, 24.2, 24.2, 25.0 (CHⁱ₃^Pr), 25.9 (d, J_C,P

5.6 Hz, CH₂), 27.6, 28.2 (CH^iPr), 37.1 (d, J_C,P

5.5 Hz,

CH₂), 52.7 (d, J_C,P28.6 Hz, PCH), 123.2Á138.6

(CH_arom, C_ipso), 142.0 (NC_ipso), 184.2 (d, J_C,P6.7

Hz, Cꢁ

N); ³¹P{¹H}-NMR (CDCl₃, 121 MHz): [ppm]

dꢁ 1599.5 (s, CꢁN);

53.29 (s); IR (KBr): [cm^ꢂ1] nꢁ

SIMS (NBA), cation: m/z (I_rel.(%))ꢁ600 (60)

[(P^ﬄN)Pd(Cl)]^ꢀ, 578 (67) [(P^ﬄN)Pd(CH₃)]^ꢀ, 562 (19)

[(P^ﬄN)Pdꢂ1]^ꢀ, 376 (83) [270ꢀPd]^ꢀ, 291 (14)

[PdPPh₂]^ꢀ, 272 (100) [(P^ﬄN)ꢀPPh₂]^ꢀ, 270 (54)

[C₁₉H₂₈N]^ꢀ, 230 (56) [H₃C(CH₂)₂CNAr]^ꢀ, 228 (90)

[H₃CCH₂CHPPh₂ꢀ 226 (26), 214 (24)

1]^ꢀ,

[CH₂CHPPh₂]^ꢀ, 212 (14), 201 (11) [CH₂CNAr]^ꢀ, 186

(28) [PPh₂ꢀ

1]^ꢀ, 183 (12), 172 (14), 133 (12); SIMS

(NBA), Anion: m/z (I_rel.(%))ꢁ614 (100) [Mꢂ

1]^ꢂ, 598

(6) [Mꢂ

CH₃]^ꢂ, 341 (5) [Clꢀ2NBA]^ꢂ, 188 (54) [Clꢀ

NBA]^ꢂ.

/

0.55 (d, Jꢁ

/

ꢁ

/

ꢁ

/

26.0 Hz,

ꢁ

/

,

/

ꢁ

/

ꢁ

/

ꢂ

/

ꢁ

/

ꢁ

/

ꢁ

/

PPh₂]^ꢀ, 310 (74) [(P^ﬄN)ꢀ

/

ꢁ

/

[PdPPh₂]^ꢀ, 256 (15), 254 (15), 252 (11), 238 (12),

236 (10), 214 (17) [CH₂CHCNAr]^ꢀ, 212 (19)

[CH₂CHPPh₂]^ꢀ, 201 (19), 196 (12), 186 (29)

ꢁ

/

[CNArꢂ

m/z (I_rel.(%))ꢁ

NBA]^ꢂ.

/

1]^ꢀ, 183 (17), 133 (100); SIMS (NBA), anion:

654 (100) [Mꢂ

1]^ꢂ, 188 (25) [Clꢀ

/

3.4.8. [{2,6-Diisopropyl-N-(2-diphenylphosphino-

cycloheptylidene)aniline-k²-P,N}(chloro)(methyl)-

palladium(II)]; (dppCyHeptPA)Pd(CH₃)Cl (26)

Scale: 434.8 mg (1.640 mmol) (cod)Pd(CH₃)Cl; 747.6

mg (1.641 mmol) (7); Yield: 963.7 mg (1.573 mmol, 96%)

white solid. Anal. Found: C, 62.83; H, 6.80; N, 2.35.

Calc. for C₃₂H₄₁ClNPPd: C, 62.75; H, 6.75; N, 2.29%.

/

3.5. Synthesis of cationic palladium complexes

3.5.1. General procedure D

¹H-NMR (CD₂Cl₂, 300 MHz): [ppm] dꢁ

3H, PdCH₃), 0.69, 0.99, 1.00, 1.34 (4*d, Jꢁ

4*3H, CHⁱ₃^Pr), 1.18Á

1.32 (br m, 2H, CH₂), 1.50Á

(m, 6H, CH₂), 2.05Á

2.25 (br m, 3H, CH₂, CH^iPr), 2.72

(hept., Jꢁ

6.9 Hz, 1H, CH^iPr), 3.88 (br m, 1H, PCH),

6.95Á

7.84 (m, 13H, H_arom); ¹³C{¹H}-NMR (CD₂Cl₂, 75

MHz): [ppm] dꢁ 4.7 (PdCH₃), 23.6, 24.6, 24.7, 24.8

(CH₃^iPr), 25.4, 28.3 (CH₂), 28.5, 28.5 (CH^iPr), 30.7

(CH₂), 30.9 (d, J_C,P11.0 Hz, CH₂), 35.7 (d, J_C,P

7.1 Hz, CH₂), 123.9Á139.3 (CH_arom, C_ipso), 143.2

(NC_ipso), 186.7 (d, J_C,P

6.3 Hz, Cꢁ

N); ³¹P{¹H}-

NMR (CD₂Cl₂, 121 MHz): [ppm] dꢁ51.73 (s); IR

(KBr): [cm^ꢂ1] nꢁ

1604.2 (s, CꢁN); SIMS (NBA),

cation: m/z (I_rel.(%))ꢁ

598 (23) [(P^ﬄN)Pd(Cl)]^ꢀ, 576

(36) [(P^ﬄN)Pd(CH₃)]^ꢀ, 560 (10) [(P^ﬄN)Pdꢂ1]^ꢀ, 374

(20) [268ꢀ

Pd]^ꢀ, 270 (100) [(P^ﬄN)ꢀPPh₂]^ꢀ, 268 (58)

[(CH₂)₅CHPPh₂]^ꢀ, 266 (11); SIMS (NBA), anion: m/z

(I_rel.(%))ꢁ612 (100) [Mꢂ

1]^ꢂ, 459 (64), 352 (18), 341

(29) [Clꢀ

2NBA]^ꢂ, 321 (13), 190 (17), 188 (86) [Clꢀ

NBA]^ꢂ.

/

0.58 (br s,

6.9 Hz,

1.90

/

0.7 mmol of the relevant (chloro)(methyl)palladiu-

m(II) complex [(P^ﬄN)Pd(CH₃)Cl] are dissolved in 4 ml

CH₂Cl₂and 0.4 ml MeCN. To this solution, kept under

vigorous stirring, 1.02 equivalents of AgSbF₆suspended

in 4 ml CH₂Cl₂are added at a temperature ranging from

0 to 208C, causing the immediate precipitation of silver

chloride. The suspension is stirred for 5 min, AgCl is

filtered on Celite^†and the clear solution concentrated

to 1 ml. The product is obtained by adding 20 ml of n-

pentane, isolated and dried in vacuo.

/

ꢂ

/

ꢁ

/

ꢁ

/

ꢁ

/

3.5.2. [(Acetonitrile){2,6-dimethyl-N-(2-

diphenylphosphino-cyclopentylidene)aniline-k²-

P,N}(methyl)palladium(II)]hexaﬂuoroantimonate;

[(dppCyPentMA)Pd(CH₃)(NCCH₃)]SbF₆(10)

Scale: 273.2 mg (0.517 mmol) (9); 174.9 mg (0.509

mmol) AgSbF₆; Yield: 351.0 mg (0.456 mmol, 90%)

white powder. Anal. Found: C, 43.74; H, 4.20; N, 3.68.

/

W. Keim et al. / Journal of Organometallic Chemistry 662 (2002) 150Á

/

171

167

Calc. for C₂₈H₃₂F₆N₂PPdSb: C, 43.69; H, 4.19; N,

3.64%.

3.5.4. [(Acetonitrile){2,6-dimethyl-N-(2-

diphenylphosphino-cyclohexylidene)aniline-k²-

P,N}(methyl)palladium(II)]hexaﬂuoroantimonate;

[(dppCyHexMA)Pd(CH₃)(NCCH₃)]SbF₆(16)

¹H-NMR (CD₂Cl₂, 300 MHz): [ppm] dꢁ

/

0.34 (d,

1.70 (m, 2H, CH₂),

2.24 (br m, 4H, CH₂), 2.12,

2.16 (2*s, 2*3H, CH₃), 4.39 (m, 1H, PCH), 7.01Á7.86

(m, 13H, H_arom); ¹³C{¹H}-NMR (CD₂Cl₂, 75 MHz):

[ppm] dꢁ 3.1 (PdCH₃), 2.0 (NCCH₃), 18.2, 18.9

(CH₃), 26.6 (d, J_C,P6.3 Hz, CH₂), 27.8 (d, J_C,P9.3

Hz, CH₂), 30.6 (d, J_C,P7.0 Hz, CH₂), 58.5 (d, J_C,P

30.0 Hz, PCH), 119.5 (NCCH₃), 124.5Á137.0 (CH_arom

_ipso), 145.5 (NC_ipso), 195.8 (d, J_C,P

³¹P{¹H}-NMR (CD₂Cl₂, 121 MHz): [ppm] dꢁ

IR (KBr): [cm^ꢂ1] nꢁ

1661.0 (m, Cꢁ

(w, CꢂN); SIMS (DTE/DTT/Sul), cation: m/z (I_rel.

(%))ꢁ DTE/DTTꢂ

630 (15) [(P^ﬄN)Pdꢀ 1]^ꢀ, 492 (43)

[(P^ﬄN)Pd(CH₃)]^ꢀ, 477 (22) [(P^ﬄN)Pd]^ꢀ, 372 (4)

[(P^ﬄN)ꢀ1]^ꢀ, 370 (6) [(P^ﬄN)ꢂ1]^ꢀ, 291 (11)

[PdPPh₂]^ꢀ, 186 (100) [(P^ﬄN)ꢀ 1]^ꢀ; SIMS

PPh₂, PPh₂ꢀ

235 (100)

J_H,P

ꢁ

/

1.8 Hz, 3H, PdCH₃), 1.48Á

/

1.73 (s, 3H, NCCH₃), 2.01Á

/

Scale: 354.9 mg (0,654 mmol) (15); 230.8 mg (0.672

mmol) AgSbF₆; yield: 474.7 mg (0.605 mmol, 92%)

white solid. Anal. Found: C, 44.58; H, 4.42; N, 3.61.

Calc. for C₂₉H₃₄F₆N₂PPdSb: C, 44.44; H, 4.37; N,

3.57%.

/

ꢂ

/

ꢁ

/

ꢁ

/

ꢁ

/

ꢁ

/

¹H-NMR (CDCl₃, 300 MHz): [ppm] dꢁ

J_H,P1.8 Hz, 3H, PdCH₃), 1.17Á1.32 (m, 2H, CH₂),

1.60Á1.83 (m, 4H, CH₂), 1.74 (s, 3H, NCCH₃), 2.01,

2.20 (2*s, 2*3H, CH₃), 2.16Á2.40 (m, 2H, CH₂), 4.00 (m,

1H, PCH), 7.00Á

7.69 (m, 13H, H_arom); ¹³C{¹H}-NMR

(CDCl₃, 75 MHz): [ppm] dꢁ 3.2 (PdCH₃), 1.3

(NCCH₃), 17.9, 18.5 (CH₃), 25.2 (d, J_C,P8.3 Hz,

CH₂), 26.3 (CH₂), 32.3 (d, J_C,P3.2 Hz, CH₂), 32.6 (d,

J_C,P6.1 Hz, CH₂), 53.8 (d, J_C,P31.2 Hz, PCH),

118.5 (NCCH₃), 124.4Á135.6 (CH_arom, C_ipso), 144.6

(NC_ipso), 186.0 (d, J_C,P

5.3 Hz, Cꢁ

N); ³¹P{¹H}-

NMR (CDCl₃, 121 MHz): [ppm] dꢁ52.85 (s); IR

(KBr): [cm^ꢂ1] nꢁ

1622.7 (m, CꢁN), 2318.2, 2289.6 (w,

CꢂN); SIMS (NBA), cation: m/z (I_rel.(%))ꢁ506 (17)

[(P^ﬄN)Pd(CH₃)]^ꢀ, 491 (3) [(P^ﬄN)Pd]^ꢀ, 384 (2)

[(P^ﬄN)ꢂ1]^ꢀ, 327 (4), 291 (12) [PdPPh₂]^ꢀ, 281 (7),

221 (6), 214 (5), 200 (100) [(P^ﬄN)ꢀPPh₂]^ꢀ, 198 (13)

[CHPPh₂]^ꢀ, 147 (33); SIMS (NBA), anion: m/z (I_rel.

(%))ꢁ

235 (100) [SbF₆]^ꢂ.

/

0.32 (d,

/

,

ꢁ

/

C

ꢁ

/

9.0 Hz, Cꢁ

/

N);

/

44.51 (s).

/

N), 2309.2, 2282.1

/

ꢂ

/

ꢁ

/

ꢁ

/

ꢁ

/

ꢁ

/

(DTE/DTT/Sul), Anion: m/z (I_rel.(%))ꢁ

/

ꢁ

/

[SbF₆]^ꢂ.

/

3.5.3. [(Acetonitrile){2,6-diisopropyl-N-(2-

diphenylphosphino-cyclopentylidene)aniline-k²-P,N}

(methyl)palladium(II)]hexaﬂuoroantimonate;

[(dppCyPentPA)Pd(CH₃)(NCCH₃)]SbF₆(13)

Scale: 464.6 mg (0.795 mmol) (12); 276.7 mg (0.805

mmol) AgSbF₆; yield: 631.6 mg (0,765 mmol, 96%)

white powder. Anal. Found: C, 46.53; H, 4.92; N, 3.30.

Calc. for C₃₂H₄₀F₆N₂PPdSb: C, 46.54; H, 4.88; N,

3.39%.

/

3.5.5. [(Acetonitrile){2,6-diisopropyl-N-(2-

diphenylphosphino-cyclohexylidene)aniline-k²-

P,N}(methyl)palladium(II)]hexaﬂuoroantimonate;

[(dppCyHexPA)Pd(CH₃)(NCCH₃)]SbF₆(19)

Scale: 447.3 mg (0.747 mmol) (18); 260.8 mg (0.759

mmol) AgSbF₆; yield: 612.8 mg (0.730 mmol, 98%)

white powder. Anal. Found: C, 47.32; H, 5.10; N, 3.36.

Calc. for C₃₃H₄₂F₆N₂PPdSb: C, 47.20; H, 5.04; N,

3.34%.

¹H-NMR (CDCl₃, 300 MHz): [ppm] dꢁ

J_H,P2.1 Hz, 3H, PdCH₃), 0.95, 1.16, 1.21, 1.40 (4*d,

Jꢁ 1.76 (m, 2H, CH₂), 1.71

6.9 Hz, 4*3H, CHⁱ₃^Pr), 1.49Á

(s, 3H, NCCH₃), 1.98Á2.30 (m, 4H, CH₂), 2.89 (hept.,

Jꢁ 6.9 Hz, 1H,

6.9 Hz, 1H, CH^iPr), 2.96 (hept., Jꢁ

CH^iPr), 4.67 (dt, J_H,H

7.8 Hz, J_H,P11.4 Hz, 1H,

PCH), 7.13Á

7.85 (m, 13H, H_arom); ¹³C{¹H}-NMR

(CDCl₃, 75 MHz): [ppm] dꢁ 3.2 (d, J_C,P2.1 Hz,

PdCH₃), 1.3 (NCCH₃), 23.5, 23.7, 23.8, 24.5 (CHⁱ₃^Pr),

25.9 (d, J_C,P6.6 Hz, CH₂), 27.0 (d, J_C,P9.4 Hz,

CH₂), 28.2, 28.3 (CH^iPr), 30.9 (d, J_C,P

7.0 Hz, CH₂),

57.1 (d, J_C,P30.0 Hz, PCH), 119.0 (NCCH₃), 124.9Á

138.6 (CH_arom, C_ipso), 142.2 (NC_ipso), 195.7 (d, J_C,P

8.7 Hz, Cꢁ

N); ³¹P{¹H}-NMR (CDCl₃, 121 MHz):

[ppm] dꢁ 1653.4 (s,

45.07 (s); IR (KBr): [cm^ꢂ1] nꢁ

CꢁN), 2317.6, 2289.7 (w, CꢂN); SIMS (DTE/DTT/Sul),

cation: m/z (I_rel.(%))ꢁ DTE/

686 (7) [(P^ﬄN)Pdꢀ

DTTꢂ

1]^ꢀ, 548 (37) [(P^ﬄN)Pd(CH₃)]^ꢀ, 533 (22)

[(P^ﬄN)Pd]^ꢀ, 346 (12) [C₁₇H₂₂NPd]^ꢀ, 291 (4)

/

0.33 (d,

ꢁ

/

ꢁ

/

ꢁ

/

ꢂ

/

ꢁ

/

¹H-NMR (CDCl₃, 300 MHz): [ppm] dꢁ

J_H,P1.5 Hz, 3H, PdCH₃), 1.08, 1.09, 1.16 (3*d, Jꢁ

6.9 Hz, 3*3H, CHⁱ₃^Pr), 1.16Á

1.30 (m, 2H, CH₂), 1.39 (d,

Jꢁ 1.96

6.9 Hz, 3H, CHⁱ₃^Pr), 1.69 (s, 3H, NCCH₃), 1.68Á

(m, 4H, CH₂), 2.20 (m, 1H, CH₂), 2.44 (m, 1H, CH₂),

2.63 (hept., Jꢁ 6.9

6.9 Hz, 1H, CH^iPr), 2.90 (hept., Jꢁ

Hz, 1H, CH^iPr), 4.07 (m, 1H, PCH), 7.13Á

7.71 (m, 13H,

_arom); ¹³C{¹H}-NMR (CDCl₃, 75 MHz): [ppm] dꢁ

3.6 (PdCH₃), 1.1 (NCCH₃), 23.4, 23.5, 23.7, 23.8

(CHⁱ₃^Pr), 24.8 (d, J_C,P

8.1 Hz, CH₂), 25.3 (CH₂),

28.0, 28.3 (CH^iPr), 31.5 (d, J_C,P

3.5 Hz, CH₂), 33.3

(d, J_C,P5.9 Hz, CH₂), 53.5 (d, J_C,P30.7 Hz, PCH),

118.8 (NCCH₃), 123.7Á138.9 (CH_arom, C_ipso), 141.8

(NC_ipso), 185.5 (d, J_C,P

6.3 Hz, Cꢁ

N); ³¹P{¹H}-

NMR (CDCl₃, 121 MHz): [ppm] dꢁ53.41 (s); IR

(KBr): [cm^ꢂ1] nꢁ

1620.8 (m, CꢁN), 2319.4, 2291.6 (w,

CꢂN); SIMS (DTE/DTT/Sul), cation: m/z (I_rel.(%))ꢁ

/0.29 (d,

ꢁ

/

ꢁ

/

ꢁ

/

ꢁ

/

ꢁ

/

ꢁ

/

H

/

ꢂ

/

ꢁ

/

ꢁ

/

ꢁ

/

ꢁ

/

[PdPPh₂]^ꢀ, 242 (58) [(P^ﬄN)ꢀ

/

PPh₂]^ꢀ, 240 (27)

/

[C₁₇H₂₂N]^ꢀ, 238 (7), 226 (6) [(CH₂)₂CHPPh₂]^ꢀ, 147

(19), 109 (26), 97 (13), 95 (40), 93 (16), 83 (25), 81 (95),

69 (100), 67 (31); SIMS (DTE/DTT/Sul), Anion: m/z

ꢁ

/

(I_rel.(%))ꢁ

/

235 (100) [SbF₆]^ꢂ.

/

168

W. Keim et al. / Journal of Organometallic Chemistry 662 (2002) 150Á171

/

700 (16) [(P^ﬄN)Pdꢀ

/

DTE/DTTꢂ

/

1]^ꢀ, 562 (32)

MHz): [ppm] dꢁ

/

ꢂ

/

3.6,

(NCCH₃), 22.0 (br, CH₂), 23.4, 23.5, 23.8, 23.9 (CHⁱ₃^Pr),

ꢂ3.5 (2*s, PdCH₃), 1.2

/

[(P^ﬄN)Pd(CH₃)]^ꢀ, 547 (22) [(P^ﬄN)Pd]^ꢀ, 360 (28)

[(CH₂)₄CHPPh₂Pd]^ꢀ, 291 (10) [PdPPh₂]^ꢀ, 256 (100)

26.3 (br, CH₂), 26.7, 27.1 (CH^t₃^Bu), 28.1, 28.3 (CH^iPr),

[(P^ﬄN)ꢀ

/

PPh₂]^ꢀ, 254 (36) [(CH₂)₄CHPPh₂]^ꢀ, 240 (10)

32.7 (br, CH₂), 32.3, 34.1 (CMe₃), 42.6 (d, J_C,P

CH^tBu), 45.8 (d, J_C,P6.9 Hz, CH^tBu), 50.2 (d, J_C,P

30.0 Hz, PCH), 53.0 (d, J_C,P30.1 Hz, PCH), 118.6 (br,

NCCH₃), 123.7Á139.0 (CH_arom, C_ipso), 141.6, 141.9

(NC_ipso), 185.8 (d, J_C,PN), 188.2 (d,

5.3 Hz, Cꢁ

J_C,P

5.4 Hz, Cꢁ

N); ³¹P{¹H}-NMR (CDCl₃, 121

MHz): [ppm] dꢁ53.66 (s, ca. 0.75P), 54.00 (s, ca.

0.25P); IR (KBr): [cm^ꢂ1] nꢁ

1628.3 (s, CꢁN), 2319.7,

2292.4 (w, CꢂN); SIMS (DTE/DTT/Sul), cation: m/z

(I_rel.(%))ꢁ DTE/DTTꢂ

756 (43) [(P^ﬄN)Pdꢀ 1]^ꢀ, 618

(80) [(P^ﬄN)Pd(CH₃)]^ꢀ, 603 (43) [(P^ﬄN)Pd]^ꢀ, 416 (55)

[310ꢀ

Pd]^ꢀ, 312 (100) [(P^ﬄN)ꢀPPh₂]^ꢀ, 310 (53)

[(P^ﬄN)ꢀCNAr]^ꢀ, 291 (20) [PdPPh₂]^ꢀ, 256 (13), 254

(12), 214 (27) 212 (16)

[CH₂CHCNAr]^ꢀ,

[CH₂CHPPh₂]^ꢀ, 201 (12), 186 (20) [CNAr-1, Ph₂Pꢀ

1]^ꢀ, 183 (17), 133 (94); SIMS (DTE/DTT/Sul), Anion:

m/z (I_rel.(%))ꢁ

235 (100) [SbF₆]^ꢂ.

ꢁ/5.1 Hz,

[(CH₂)₃CHPPh₂]^ꢀ, 214 (16), 212 (11) [CH₂CHPPh₂]^ꢀ,

133 (67), 73 (41); SIMS (DTE/DTT/Sul), Anion: m/z

ꢁ

/

ꢁ

/

ꢁ

/

(I_rel.(%))ꢁ

235 (100) [SbF₆]^ꢂ.

/

ꢁ

/

ꢁ

/

3.5.6. [(Acetonitrile){2-methoxy-N-(2-

diphenylphosphino-cyclohexylidene)aniline-k²-

P,N}(methyl)palladium(II)]hexaﬂuoroantimonate;

[(dppCyHexMOA)Pd(CH₃)(NCCH₃)]SbF₆(22)

Scale: 142.8 mg (0.262 mmol) (21); 93.8 mg (0.273

mmol) AgSbF₆; Yield: 190.0 mg (0.242 mmol, 92%)

bright yellow powder. Anal. Found: C, 42.68; H, 4.05;

N, 3.52. Calc. for C₂₈H₃₂F₆N₂OPPdSb: C, 42.80; H,

4.10; N, 3.56%.

/

¹H-NMR (CDCl₃, 300 MHz): [ppm] dꢁ

3H, PdCH₃), 1.20Á1.79 (br m, 5H, CH₂), 1.84 (s, 3H,

NCCH₃), 2.20 (m, 1H, CH₂), 2.46 (m, 2H, CH₂), 3.82 (s,

3H, OCH₃), 3.85 (m, 1H, PCH), 6.88Á7.72 (m, 14H,

_arom); ¹³C{¹H}-NMR (CDCl₃, 75 MHz): [ppm] dꢁ

4.2 (PdCH₃), 1.6 (NCCH₃), 25.1 (d, J_C,P7. Hz, CH₂),

27.8 (CH₂), 31.2 (br, CH₂), 33.2 (d, J_C,P5.2 Hz, CH₂),

53.7 (br, PCH), 55.9 (s, OCH₃), 118.7 (NCCH₃), 111.6Á

135.5 (CH_arom, C_ipso), 150.0 (NC_ipso), 182.4 (br, CꢁN);

³¹P{¹H}-NMR (CDCl₃, 121 MHz): [ppm] dꢁ

53.07 (br

s); IR (KBr): [cm^ꢂ1] nꢁ

1625.9 (m, CꢁN), 2318.6,

2290.7 (w, CꢂN); SIMS (DTE/DTT/Sul), cation: m/z

(I_rel.(%))ꢁ DTE/DTTꢂ

646 (5) [(P^ﬄN)Pdꢀ 1]^ꢀ, 508

(45) [(P^ﬄN)Pd(CH₃)]^ꢀ, 493 (8) [(P^ﬄN)Pd]^ꢀ, 388 (5),

291 (4) [PdPPh₂]^ꢀ, 202 (100) [(P^ﬄN)ꢀPPh₂]^ꢀ, 185 (4),

/0.31 (br s,

/

H

/

ꢂ

/

ꢁ

/

3.5.8. [(Acetonitrile){2,6-diisopropyl-N-(2-

diphenylphosphino-cycloheptylidene)aniline-k²-

P,N}(methyl)palladium(II)]hexaﬂuoroantimonate;

[(dppCyHeptPA)Pd(CH₃)(NCCH₃)]SbF₆(27)

Scale: 474.0 mg (0.774 mmol) (26); 275.0 mg (0.800

mmol) AgSbF₆; yield: 640.0 mg (0.750 mmol, 97%)

white powder. Anal. Found: C, 47.90; H, 5.23; N, 3.34.

Calc. for C₃₄H₄₄F₆N₂PPdSb: C, 47.83; H, 5.19; N,

3.28%.

ꢁ

/

¹H-NMR (CDCl₃, 300 MHz): [ppm] dꢁ

J_H,P1.2 Hz, 3H, PdCH₃), 0.81, 0.94, 1.11, 1.27 (4*d,

Jꢁ 1.53 (br m, 2H, CH₂),

6.9 Hz, 4*3H, CHⁱ₃^Pr), 1.20Á

1.70 (s, 3H, NCCH₃), 1.68Á1.95 (m, 6H, CH₂), 2.20

(hept., Jꢁ 6.6 Hz, 2H,

6.9 Hz, 1H, CH^iPr), 2.31 (t, Jꢁ

CH₂), 2.74 (hept., Jꢁ

6.9 Hz, 1H, CH^iPr), 4.16 (m, 1H,

PCH), 7.06Á

7.74 (m, 13H, H_arom); ¹³C{¹H}-NMR

(CDCl₃, 75 MHz): [ppm] dꢁ 4.1 (PdCH₃), 1.3

(NCCH₃), 23.3, 23.8, 23.8, 24.3 (CHⁱ₃^Pr), 24.2, 27.6

(CH₂), 27.9, 28.0 (CH^iPr), 29.7 (d, J_C,P

11.1 Hz, CH₂),

30.2 (CH₂), 35.1 (d, J_C,P3.5 Hz, CH₂), 53.9 (d, J_C,P

31.0 Hz, PCH), 118.8 (NCCH₃), 124.0Á139.0 (CH_arom

C_ipso), 141.7 (NC_ipso), 188.8 (d, J_C,PN);

5.0 Hz, Cꢁ

³¹P{¹H}-NMR (CDCl₃, 121 MHz): [ppm] dꢁ

54.43 (s);

IR (KBr): [cm^ꢂ1] nꢁ

1606.9 (m, CꢁN), 2319.0, 2290.8

(w, CꢂN); SIMS (DTE/DTT/Sul), cation: m/z (I_rel.

(%))ꢁ DTE/DTTꢂ

714 (22) [(P^ﬄN)Pdꢀ 1]^ꢀ, 576 (67)

[(P^ﬄN)Pd(CH₃)]^ꢀ, 561 (23) [(P^ﬄN)Pd]^ꢀ, 387 (18), 374

(30) [(CH₂)₅CHPPh₂ꢀ

Pd]^ꢀ, 291 (12) [PdPPh₂]^ꢀ, 270

/0.50 (d,

183 (4); SIMS (DTE/DTT/Sul), anion: m/z (I_rel.(%))ꢁ

/

235 (100) [SbF₆]^ꢂ, 119 (11).

ꢁ

/

3.5.7. [(Acetonitrile){2,6-diisopropyl-N-(4-tert.-butyl-

2-diphenylphosphino-cyclohexylidene)-aniline-k²-

P,N}(methyl)palladium(II)]hexaﬂuoroantimonate;

[(dpptBuCyHexPA)Pd(CH₃)(NCCH₃)]SbF₆(24)

Scale: 466.7 mg (0.713 mmol) (23); 251.2 mg (0.731

mmol) AgSbF₆; yield: 596.4 mg (0.667 mmol, 93%)

white powder. Anal. Found: C, 49.68; H, 5.67; N, 3.18.

Calc. for C₃₇H₅₀F₆N₂PPdSb: C, 49.60; H, 5.62; N,

3.13%.

Being the compound obtained as a mixture of

diastereoisomers in the approximate ratio of 3:1, an

assignment of the NMR signals can only tentatively be

given.

/

ꢂ

/

ꢁ

/

ꢁ

/

ꢁ

/

,

ꢁ

/

¹H-NMR (CDCl₃, 300 MHz): [ppm] dꢁ

(2*s, 3H, PdCH₃), 0.63, 0.65 (2*s, 9H, CH^t₃^Bu), 0.78Á

0.83 (m, 2H, CH₂), 1.03, 1.08, 1.10, 1.16 (4*d, Jꢁ6.9

Hz, 4*3H, CHⁱ₃^Pr), 1.77 (s, 3H, NCCH₃), 1.50Á

2.56 (br

m, 5H, CH, CH₂), 2.64 (br m, 1H, CH^iPr), 2.91 (br m,

1H, CH^iPr), 4.18 (m, 1H, PCH), 7.15Á

7.74 (m, 13H,

_arom); ¹³C{¹H}-NMR [selected signals] (CDCl₃, 75

/0.31, 0.34

/

(100) [(P^ﬄN)ꢀ

/

PPh₂]^ꢀ, 268 (41) [(CH₂)₅CHPPh₂]^ꢀ, 226

/

(10) [(CH₂)₂CHPPh₂]^ꢀ, 147 (18), 133 (86), 119 (13), 85

(23), 73 (59); SIMS (DTE/DTT/Sul), Anion: m/z (I_rel.

(%))ꢁ

235 (100) [SbF₆]^ꢂ.

/

H

/

W. Keim et al. / Journal of Organometallic Chemistry 662 (2002) 150Á

/

171

169

3.5.9. [(Acetonitrile){2,6-diisopropyl-N-(2-

diphenylphosphino-1-n-propyl-butylidene)aniline-k²-

P,N}(methyl)palladium(II)]hexaﬂuoroantimonate;

[(dppHeptPA)Pd(CH₃)(NCCH₃)]SbF₆(30)

Scale: 513.4 mg (0.835 mmol) (29); 296.6 mg (0.863

mmol) AgSbF₆; yield: 683.1 mg (0.798 mmol, 96%)

white powder. Anal. Found: C, 47.70; H, 5.38; N, 3.23.

Calc. for C₃₄H₄₆F₆N₂PPdSb: C, 47.71; H, 5.42; N,

3.27%.

Found: C, 57.12; H, 6.20; N, 2.00. Calc. for

C₃₄H₄₄Br₂NNiP: C, 57.02; H, 6.19; N, 1.96%; (28)

Found: C, 55.15; H, 5.71; N, 2.08. Calc. for

C₃₁H₃₈Br₂NNiP: C, 55.23; H, 5.68; N, 2.08%; (31)

Found: C, 55.10; H, 5.91; N, 2.12. Calc. for

C₃₁H₄₀Br₂NNiP: C, 55.07; H, 5.96; N, 2.07%.

3.7. Typical procedure for palladium catalysed alkene

oligomerisation

¹H-NMR (CDCl₃, 300 MHz): [ppm] dꢁ

3H, PdCH₃), 0.62 (d, Jꢁ

6.9 Hz, 3H, CHⁱ₃^Pr), 0.76, 0.77

(2*t, Jꢁ7.2 Hz, 2*3H, CH₃), 1.07, 1.10, 1.22 (3*d, Jꢁ

6.9 Hz, 3*3H, CHⁱ₃^Pr), 1.73 (br s, 3H, NCCH₃), 1.59Á

2.29 (m, 7H, CH₂, CH^iPr), 2.60 (hept., Jꢁ

6.9 Hz, 1H,

CH^iPr), 3.98 (m, 1H, PCH), 7.07Á

7.62 (m, 13H, H_arom);

¹³C{¹H}-NMR (CDCl₃, 75 MHz): [ppm] dꢁ

4.4

(PdCH₃), 1.3 (NCCH₃), 12.9 (d, J_C,P6.5 Hz, CH₃),

14.3 (CH₃), 19.8 (CH₂), 22.8, 23.5, 23.5, 24.8 (CHⁱ₃^Pr),

26.2 (d, J_C,P

3.5 Hz, CH₂), 27.7, 28.0 (CH^iPr), 37.0 (d,

J_C,P5.9 Hz, CH₂), 53.4 (d, J_C,P32.3 Hz, PCH),

118.7 (NCCH₃), 123.4Á138.9 (CH_arom, C_ipso), 141.5

(NC_ipso), 187.6 (d, J_C,P

5.0 Hz, Cꢁ

N); ³¹P{¹H}-

NMR (CDCl₃, 121 MHz): [ppm] dꢁ55.72 (s); IR

(KBr): [cm^ꢂ1] nꢁ

1609.3 (s, CꢁN), 2318.6, 2291.1 (w,

Cꢂ

716 (43) [(P^ﬄN)Pdꢀ

/0.60 (br s,

/

The ethylene oligomerisation tests were performed

under a constant ethylene pressure in 75 ml steel

autoclaves equipped with glass inlets and magnetic

stirring bar. A Schlenk tube was added of 0.05 mmol

catalyst and 5 ml solvent and the obtained solution

transferred into the autoclave, washing the tube with

/

ꢂ

/

ꢁ

/

other 3ꢃ5 ml solvent. The autoclave was then set to the

/

ꢁ

/

desired constant ethylene pressure, temperature and

stirring rate (set to 1000 rpm). After reaction time

(typically 2 h) the autoclave was cooled in an ice bath

ꢁ

/

ꢁ

/

ꢁ

/

and opened. The obtained butenes were collected at ꢂ

/

78 8C and their quantity determined by weighing. The

liquid products were added of a weighed amount of

internal standard (n-nonane) and analysed by GC.

/

N); SIMS (DTE/DTT/Sul), cation: m/z (I_rel.(%))ꢁ

/

DTE/DTTꢂ

/

1]^ꢀ, 578 (46)

Reported SchulzÁFlory a-values were determined

/

[(P^ﬄN)Pd(CH₃)]^ꢀ, 564 (18) [(P^ﬄN)Pdꢀ

[C₁₉H₂₈Nꢀ

[(P^ﬄN)ꢀPPh₂]^ꢀ, 270 (26) [C₁₉H₂₈N]^ꢀ, 230 (52)

[H₃C(CH₂)₂CNAr]^ꢀ, 228 (45) [H₃CCH₂CHPPh₂ꢀ1]^ꢀ,

226 (12), 214 (14) [CH₂CHPPh₂]^ꢀ, 212 (8), 186 (16)

[PPh₂ꢀ

1]^ꢀ, 172 (8), 133 (18); SIMS (DTE/DTT/Sul),

Anion: m/z (I_rel.(%))ꢁ

235 (100) [SbF₆]^ꢂ.

/

1]^ꢀ, 376 (40)

from the ratio of C₁₀and C₈product quantity. The

palladium catalysed oligomerisation of propene and 1-

butene were conducted in the batch mode in steel

autoclaves. In the first case, after filling of the autoclave

with the catalyst solution (see above) the desired

quantity of propene or 1-butene was pressed under

vigorous stirring. After the desired reaction time, the

autoclave was cooled in an ice bath and opened. The

internal standard was added and the reaction mixture

analysed by GC. In order to determine product linearity

in high oligomer fraction, a part of the liquid product

was hydrogenated on Pd/C and then analysed by CG.

/

Pd]^ꢀ, 291 (9) [PdPPh₂]^ꢀ, 272 (100)

/

3.6. Synthesis of P^ﬄN nickel(II) bromide complexes

0.4 mmol of (1,2-dimethoxyethane)nickel(II)bromide

are suspended in 4 ml CH₂Cl₂at r.t. with the aid of an

ultrasound bath and slowly reacted with a solution of

1.00 equivalent of ligand dissolved in 3 ml CH₂Cl₂. The

suspension colour turns into red brown. It is vigorously

stirred for 1 h and eventually filtered with Celite^†. The

filtrate is concentrated, washed with n-pentane and

dried in vacuo. Yields are almost quantitative and the

products can be crystallised from CH₂Cl₂. NMR

measures could not be possible due to paramagnetism.

IR characterisation was reported in the discussion (vide

supra).

3.8. Typical procedure for ethylene oligomerisation

catalysed by [(P^ﬄN)NiBr₂]/MAO

1.3 ml of a 10% MAO solution in toluene was added

to a solution obtained dissolving 0.02 mmol of the

relevant (P^ﬄN)NiBr₂complex in 19.0 ml toluene

(MAO/Ni$100 mol/mol). The above described proce-

/

Elemental analyses: (11) Found: C, 50.95; H, 4.50; N,

2.39. Calc. for C₂₅H₂₆Br₂NNiP: C, 50.90; H, 4.44; N,

2.37%; (14) Found: C, 53.95; H, 5.38; N, 2.20. Calc. for

C₂₉H₃₄Br₂NNiP: C, 53.91; H, 5.31; N, 2.17%; (17)

Found: C, 51.80; H, 4.74; N, 2.38. Calc. for

C₂₆H₂₈Br₂NNiP: C, 51.70; H, 4.67; N, 2.32%; (20)

Found: C, 54.60; H, 5.51; N, 2.10. Calc. for

C₃₀H₃₆Br₂NNiP: C, 54.59; H, 5.50; N, 2.12%; (25)

dure was then followed. During the product workup, the

excess MAO was quenched with water, and the organic

phase extracted with toluene, dried over sodium sulfate

and then analysed by GC. In this case, the reported

SchulzÁFlory a-values were determined from the ratio

/

of C₁₂and C₁₀product quantity. In the case of the

obtainment of high molecular weight products, only the

TOF was determined.

170

W. Keim et al. / Journal of Organometallic Chemistry 662 (2002) 150Á171

/

[6] (a) M.D. Fryzuk, W.E. Piers, Organometallics 9 (1990) 986;

(b) G.A. Stark, J.A. Gladysz, Inorg. Chem. 35 (1996)

5509.

4. Supplementary material

Supplementary material contains preparation and

characterisation of alkylidene anilines p-2, p-4, p-5, p-

6, p-7, p-8, as well as of literature known p-1 and p-3.

The complete crystallographic data for 2 and 4 are also

given. Crystallographic data for these structural ana-

lyses have been deposited with the Cambridge Crystal-

lographic Data Centre, CCDC nos. 171806 for

compound 2, and 171807 for compound 4, respectively.

Copies of this information may be obtained free of

charge from The Director, CCDC, 12 Union Road,

[7] E.K. van den Beuken, W.J.J. Smeets, A.L. Spek, B.I. Feringa,

Chem. Commun. (1998) 223.

[8] K.R. Reddy, K. Surekha, G.-H. Lee, S.-M. Peng, S.-T. Liu,

Organometallics 19 (2000) 2637.

[9] Y.-C. Chen, C.-L. Chen, J.-T. Chen, S.-T. Liu, Organometallics

20 (2001) 1285.

[10] (a) K.R. Reddy, K. Surekha, C.-L. Chen, Y.-H. Liu, S.-M. Peng,

J.-T. Chen, S.-T. Liu, Organometallics 18 (1999) 2574;

(b) K.R. Reddy, K. Surekha, G.-H. Lee, S.-M. Peng, J.-T. Chen,

S.-T. Liu, Organometallics 20 (2001) 1292;

(c) K.R. Reddy, K. Surekha, G.-H. Lee, S.-M. Peng, S.-T. Liu,

Organometallics 20 (2001) 5557.

Cambridge CB2 1EZ, UK, (Fax. ꢀ44-1223-336033; e-

mail: deposit@ccdc.cam.ac.uk or www: http://

www.ccdc.cam.ac.uk).

/

[11] H. Brunner, H. Weber, Chem. Ber. 118 (1985) 3380.

[12] (a) P. von Matt, A. Pfaltz, Angew. Chem. 105 (1993) 614;

(b) J. Sprinz, G. Helmchen, Tetrahedron Lett. 34 (1993)

1769;

(c) G.J. Dawson, C.G. Frost, J.M.J. Williams, S.J. Coote,

Tetrahedron Lett. 34 (1993) 3149.

[13] M. Sperrle, A. Aeby, G. Consiglio, A. Pfaltz, Helv. Chim. Acta 79

(1996) 1387.

Acknowledgements

[14] K.R. Reddy, W.-W. Tsai, K. Surekha, G.-H. Lee, S.-M. Peng,

J.-T. Chen, S.-T. Liu, J. Chem. Soc. Dalton Trans. (2002) 1776.

[15] (a) H. Yoshida, E. Shirakawa, T. Kurahashi, Y. Nakao, T.

Hiyama, Organometallics 19 (2000) 5671;

DFG (Deutsche Forschungsgemeinschaft), and Ita-

lian MIUR are acknowledged for ﬁnancial support.

G.P.S. gratefully acknowledges Dr. Maria Rosaria

Taurino for helpful discussions.

(b) E. Shirakawa, T. Hiyama, J. Organomet. Chem. 576 (1999)

169.

[16] A. Scrivanti, U. Matteoli, V. Beghetto, S. Antonaroli, R.

Scarpelli, B. Crociani, J. Mol. Catal. A 170 (2001) 51.

[17] E. Shirakawa, Y. Murota, Y. Nakao, T. Hiyama, Synlett 10

(1997) 1143.

References

[18] E. Shirakawa, H. Hoshida, H. Takaya, Tetrahedron Lett. 38

(1997) 3759.

[19] K.S. Coleman, M.L.H. Green, S.I. Pascu, N.H. Rees, A.R.

Cowley, L.H. Rees, J. Chem. Soc. Dalton Trans. (2001)

3384.

[1] (a) A. Bader, E. Lindner, Coord. Chem. Rev. 108 (1991) 27;

(b) J.R. Dilworth, N. Wheatley, Coord. Chem. Rev. 199 (2000)

89.

[20] (a) S. Mecking, W. Keim, Organometallics 15 (1996) 2650;

(b) A. Ecke, W. Keim, M.C. Bonnet, I. Tkatschenko, F. Dahan,

Organometallics 14 (1995) 5302.

[2] (a) W. Keim, Angew. Chem. Int. Ed. Engl. 29 (1990) 235;

(b) S. Mecking, Coord. Chem. Rev. 203 (2000) 325 (and references

cited therein).

[21] I. Brassat, U. Englert, W. Keim, D.P. Keitel, S. Killat, G.P.

Suranna, R. Wang, Inorg. Chim. Acta 280 (1998) 150.

[22] I. Brassat, W. Keim, S. Killat, M. Moethrath, P. Mastrorilli, C.F.

Nobile, G.P. Suranna, J. Mol. Catal. A 157 (2000) 41.

[23] G.P. Suranna, P. Mastrorilli, C.F. Nobile, W. Keim, Inorg. Chim.

Acta 305 (2000) 151.

[3] (a) G.P.C.M. Dekker, A. Buijs, C.J. Elsevier, K. Vrieze,

P.W.N.M. van Leeuwen, W.I.J. Smeets, A.L. Spek, Y.F. Wang,

C.H. Stam, Organometallics 11 (1992) 1937;

(b) P.W.N.M. van Leeuwen, C.S. Roobeek, H. van der Heijden, J.

Am. Chem. Soc. 116 (1994) 12117.

[4] (a) P. Braunstein, F. Naud, Angew. Chem. Int. Ed. 40 (2001)

680;

[24] G. Tennant, in: I.O. Sutherland (Ed.), Comprehensive Organic

Chemistry; Vol. 2, Nitrogen Compounds, Carboxylic Acids,

Phosphorus Compounds, Pergamon Press, Oxford, 1979, chapter

8.

(b) P.J. Guiry, M. McCarthy, P.M. Lacey, C.P. Saunders, S.

Kelly, D.J. Connolly, Curr. Org. Chem. 4 (2000) 821;

(c) P. Espinet, J.K. Soulantica, Coord. Chem. Rev. 193 (1999)

499.

[25] Z. Guan, W.J. Marshall, Organometallics 21 (2002) 3580.

[26] (a) S. Patai, in: S. Patai (Ed.), The Chemistry of the CarbonÁ

/

[5] (a) P. Wehman, R.E. Rulke, V.E. Kaasjager, P.C.J. Kamer, H.

¨

Nitrogen Double Bond, Wiley, London, 1970;

(b) D.G. Gilheany, in: Patai, The Chemistry of Organopho-

sphorus Compounds, F.R. Hartley (Ed.), Wiley, Chichester,

1990.

Kooijman, A.L. Spek, C.J. Elsevier, K. Vrieze, P.W.N.M. van

Leeuwen, J. Chem. Soc. Chem. Commun. (1995) 331;

(b) H.A. Ankersmit, B.H. Løken, H. Kooijman, A.L. Spek, K.

Vrieze, G. van Koten, Inorg. Chim. Acta 252 (1996) 141;

(c) H.A. Ankersmit, N. Veldman, A.L. Spek, K. Vrieze, G. van

Koten, Inorg. Chim. Acta 252 (1996) 339;

[27] (a) B.L. Small, M. Brookhart, A.M.A. Bennett, J. Am. Chem.

Soc. 120 (1998) 4049;

(b) G.J.P. Britovsek, V.C. Gibson, B.S. Kimberley, P.J. Maddox,

S.J. McTavish, G.A. Solan, A.J.P. White, D.J. Williams, J. Chem.

Soc. Chem. Commun. (1998) 849.

(d) R.E. Rulke, V.E. Kaasjager, P. Wehman, C.J. Elsevier,

¨

P.W.N.M. van Leeuwen, K. Vrieze, J. Fraanje, K. Goubitz,

A.L. Spek, Organometallics 15 (1996) 3022;

(e) P. Wehman, H.M.A. van Donge, A. Hagos, P.C.J. Kamer,

P.W.N.M. van Leeuwen, J. Organomet. Chem. 535 (1997) 183;

(f) A.G.J. Ligtenbarg, E.K. van den Beuken, A. Meetsma, N.

Veldman, W.J.J. Smeets, A.L. Smeets, B.L. Feringa, J. Chem.

Soc. Dalton Trans. (1998) 263.

[28] P.E. Garrou, Chem. Rev. 81 (1981) 229.

[29] K. Nakamoto, Infrared and Raman Spectra of Inorganic

and Coordination Compounds, Wiley-Interscience, New York,

1986.

[30] S. Svejda, M. Brookhart, Organometallics 18 (1999) 65.

W. Keim et al. / Journal of Organometallic Chemistry 662 (2002) 150Á

/

171

[31] P.-Y. Shi, Y.-H. Liu, S.-M. Peng, S.-T. Liu, Organometallics 21

(2002) 3203.

[35] D.D. Perrin, W.L.F. Armarengo, D.R. Perrin, Puriﬁcation of

Laboratory Chemicals, 2nd ed., Pergamon Press, Oxford,

1980.

[32] B.L. Small, M. Brookhart, J. Am. Chem. Soc. 120 (1998) 7143.

[33] W. Keim, R.P. Schulz, J. Mol. Catal. 92 (1994) 21.

[34] M.D. Leathermann, M. Brookhart, Macromolecules 34 (2001)

2748 and references cited therein.

[36] D. Drew, J.R. Doyle, Inorg. Synth. 13 (1972) 52.

[37] R.E. Rulke, J.M. Ernsting, A.L. Spek, C.J. Elsevier, P.W.N.M.

¨

van Leeuwen, K. Vrieze, Inorg. Chem. 32 (1993) 5769.

Article Doi

Synthesis, characterisation and catalytic of Pd(II) and Ni(II) complexes with new cyclic α-diphenylphosphino-ketoimines. Crystal structure of 2,6-diisopropyl-N-(2-diphenylphosphino-cyclopentylidene)aniline and of 2,6-diisopropyl-N-(2-diphenylphosphino-cyclohexylidene)aniline

DOI: 10.1016/S0022-328X(02)01903-4

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