Platinum(II) and palladium(II) compounds derived from [(η5-C5H5)Fe{(η5-C 5H4)-CH=N-CH2-CH2-OH}]

www.elsevier.nl/locate/jorganchem

Journal of Organometallic Chemistry 598 (2000) 87–102

Platinum(II) and palladium(II) compounds derived from

[(h⁵-C₅H₅)Fe{(h⁵-C₅H₄)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH}]

Concepcio´n Lo´pez ^a,*, Amparo Caubet ^a, Xavier Solans ^b, Merce` Font-Bard´ıa ^b

^aDepartament de Qu´ımica Inorga`nica, Facultat de Qu´ımica, Uni6ersitat de Barcelona, Mart´ı Franque`s 1-11, E-08028 Barcelona, Spain

^bDepartament de Cristallograf´ıa, Mineralogia i Dipo`sits Minerals, Facultat de Geologia, Mart´ı Franque`s s/n, E-08028 Barcelona, Spain

Received 17 September 1999; received in revised form 29 October 1999

Abstract

The reactions of the novel ferrocenyl ligand: [(h⁵-C₅H₅)Fe{(h⁵-C₅H₄)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH}] (1) with platinum(II) and

palladium(II) salts are described. These reactions have allowed us to isolate and characterize the coordination complexes:

[Pt{[(h⁵-C₅H₄)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH]Fe(h⁵-C₅H₅)}Cl₂(dmso)] (2), [Pd{[(h⁵-C₅H₄)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH]Fe(h⁵-C₅H₅)}₂Cl₂] (3)

and the cyclopalladated derivative: [Pd{[(h⁵-C₅H₃)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH]Fe(h⁵-C₅H₅)}(m-Cl)]₂(4). Compound 4 reacts with

deuterated pyridine, triphenylphosphine or 1,2-bis(diphenylphosphino)ethane giving: [Pd{[(h⁵-C₅H₃)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH]-

Fe(h⁵-C₅H₅)}Cl(L)] (L=py-d₅(5) or PPh₃(6)) and [Pd{[(h⁵-C₅H₃)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH]Fe(h⁵-C₅H₅)}(dppe)]Cl (7), which

contain a ﬁve-membered metallacycle with a s(PdꢀC_{sp ,ferrocene}) bond. The reactions of 4 with tert-butylisonitrile or the alkynes:

2

RꢀCꢂCꢀR (with R=Et, Ph or CO₂Me) are also described and produced: [Pd{[(h⁵-C₅H₃)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH]Fe(h⁵-C₅H₅)}Cl-

(CNCMe₃)] (8) and the nine-membered palladacycles of general formula: [Pd{[(RꢀCꢁCꢀR)₂(h⁵-C₅H₃)ꢀCHꢁNꢀCH₂ꢀ

CH₂ꢀOH]Fe(h⁵-C₅H₅)}Cl(L)] (with R=Et (9), Ph (10) or CO₂Me (11)). All the compounds included in this work were

characterized by elemental analyses, infrared and NMR spectroscopy. The X-ray crystal structures of 1, 6, 8 and 10 are also

Keywords: Platinum; Palladium; Cyclopalladation; Ferrocenyl ligand

base: [(h⁵-C₅H₅)Fe{(h⁵-C₅H₄)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH}]

(1) (Scheme 1), which contains two heteroatoms (N and

1. Introduction

O) with good electron donating abilities, and to study

its reactivity towards platinum(II) or palladium(II)

salts.

One of the areas of organometallic chemistry that has

attracted great interest during the last decade is that

concerning ferrocene derivatives containing het-

eroatoms with good electron donating abilities (i.e.

nitrogen, oxygen, sulfur, phosphorus, etc.) since the

coordination of a metal to these heteroatoms produces

polymetallic molecules [1–12]. In compounds of this

kind the presence of proximal metals may affect the

properties of iron(II). For instance, it has been proven

that the proclivity of the iron(II) to oxidize depends on

several factors [13–23] including the nature of the

transition metal and the mode of coordination of the

ferrocenyl unit to it. On these basis we attempted to

prepare and characterize the novel ferrocenyl Schiff

These reactions could produce different sorts of com-

plexes depending on the mode of coordination of the

ligand to the metal atom. The ligand may act as a

neutral monodentate group if it binds exclusively to

the nitrogen. However, if the deprotonation of the

terminal ꢀOH group and/or the activation of the

|(C_{sp ,ferrocene}ꢀH) bond in the ortho site occur, the lig-

2

and can also behave as a monoanionic mono-, bi- or

terdentate group. In this paper we report the syntheses

and characterization of a wide variety of M(II) com-

plexes (M=Pt or Pd) in which ligand 1 acts a

monodentate N-donor group or as a monoanionic

(C,N)⁻bidentate ligand, forming ﬁve-membered cyclo-

* Corresponding author. Tel.: +34-93-402-1274; fax: +34-93-490-

7725.

E-mail address: clopez@kripto.qui.ub.es (C. Lo´pez)

palladated complexes with a s(PdꢀC_{sp ,ferrocene}) bond.

2

The reactivity of this bond versus tert-butylisonitrile or

PII: S0022-328X(99)00682-8

88

C. Lo´pez et al. / Journal of Organometallic Chemistry 598 (2000) 87–102

Scheme 1. (i) cis-[PtCl₂(dmso)₂] in reﬂuxing methanol. (ii) Na₂[PdCl₄] in methanol at room temperature.

the alkynes RꢀCꢂCꢀR (with R=Et, Ph and CO₂Me) is

\CꢁNꢀ group. Despite the fact that ligand 1 could

adopt two different forms (E- or Z-), its ¹H- and

¹³C{¹H}-NMR (Tables 1 and 2) spectra, which agreed

with those reported for related ferrocenyl Schiff bases

[24–27], revealed that only one isomer (E-form) was

present in solution.

also reported.

2. Results and discussion

Compound

[(h⁵-C₅H₅)Fe{(h⁵-C₅H₄)ꢀCHꢁNꢀCH₂ꢀ

2.1. The ligand

CH₂ꢀOH}] (1) has also been characterized by X-ray

diffraction. The molecular structure of this compound

together with the atom labeling scheme is shown in Fig.

1, and a selection of bond lengths and angles is pre-

sented in Table 3.

Compound

[(h⁵-C₅H₅)Fe{(h⁵-C₅H₄)ꢀCHꢁNꢀCH₂ꢀ

CH₂ꢀOH}] (1) was prepared according to the general

procedure described for most ferrocenylketimines

[24,25]. This method consists of the reaction of equimo-

lar amounts of ferrocenecarboxaldehyde and the corre-

The structure consists of discrete molecules of [(h⁵-

C₅H₅)Fe{(h⁵-C₅H₄)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH}] (1) sepa-

rated by van der Waals contacts. The \CꢁNꢀ bond

sponding amine in reﬂuxing benzene, using

a

Dean–Stark apparatus to remove the benzene–water

azeotrope formed during the process, followed by con-

centration to dryness of the resulting solution. When

2-aminoethanol was used as starting material, this pro-

cess yielded bright-red needles of ligand 1.

The ligand was characterized by elemental analyses,

infrared and NMR spectroscopy. The elemental analy-

ses were consistent with those expected for the pro-

posed formula (see Section 3). The infrared spectrum

showed a sharp, intense band in the range 1620–1640

cm⁻¹, which is assigned to the stretching of the

,

length (1.25(2) A) is similar to those reported for

related ferrocenyl Schiff bases [26,27] and the ferrocenyl

and the CH₂ꢀCH₂OH groups are in a trans arrange-

ment as reﬂected in the torsion angle deﬁned by the set

of atoms: C(10), C(11), N and C(12) (−173.8°), thus

indicating that the ligand has the E-form. The func-

tional group \CꢁNꢀ forms an angle of 11.16° with the

substituted pentagonal ring of the ferrocenyl fragment.

Bond lengths and angles in the ferrocenyl fragment

are consistent with those reported for other ferrocene

C. Lo´pez et al. / Journal of Organometallic Chemistry 598 (2000) 87–102

89

Table 1

¹H-NMR data (500 MHz, in ppm) for the free ligand (1) and for the platinum(II) (2) and palladium(II) complexes (3–11) under study ^a

Complex

Ferrocenyl moiety

ꢀCHꢁNꢀ

\NꢀCH₂ꢀ

ꢀCH₂ꢀ

Others

1

4.16, C₅H₅

4.34, H², H⁵

4.61, H³, H⁴

4.36, C₅H₅

5.64, H², H⁵

4.73, H³, H⁴

4.35, C₅H₅

5.81, H², H⁵

4.74, H³, H⁴

4.26, C₅H₅

5.61, H², H⁵

4.59, H³, H⁴

3.89, C₅H₅

3.80, H³

8.13, s

3.83, t

3.56, t

4.18, t, ꢀOH ^b

2

8.15, s ^c

7.76, s

7.72, s

4.30, m

4.41, m

4.10, m ^g

3.85, m

3.80, m

3.60, m

3.60, m ^g

2.91, t, ꢀOH

3.42, s, SꢀCH₃

d

3 ^e

3.05, t, ꢀOH

3.10, t, ꢀOH

3.49, br, ꢀOH

4 ^f

3.96, H⁴

4.05, H⁵

5 ^f,h

4.34, C₅H₅

8.00, s

8.14, d ^j

8.60, d ^j

8.04, s

7.92, s

7.69, s

7.71, s

4.06, br, m ^g

3.78, br, m ^g

i

3.91, H³

4.25, H⁴

4.46, H⁵

6 ^f

3.88, C₅H₅

4.17, m

4.05, m

3.90, m

3.75, m

2.75, t, ꢀOH

7.30–8.25, m, Ph

3.33, H³

4.05, H⁴

4.38, H⁵

7 ^f

4.04, C₅H₅

3.60, br, m

3.20, br, m

3.30, br, m

3.76, br, m

3.00, br, ꢀOH

3.53, H³

k

4.12, H⁴

4.60, H⁵

8 ^f

4.24, C₅H₅

4.60, br, m

4.22, br, m

3.52, br, m

3.72, br, m

3.40, br, ꢀOH

1.59, s, ꢀCH₃

4.09, H³

4.28, H⁴

4.37, H⁵

9 ^f

4.35, C₅H₅

4.20, br, m ^g

4.10, br, m

3.90, br, m ^g

2.95, t, ꢀOH

3.94, H³

l

4.44, H⁴

4.57, H⁵

10 ^f

11 ^f

4.20, C₅H₅

3.28, br, m

3.89, br, m

6.90–7.50, m, Ph

4.26, H³

m

4.35, H⁴

4.68, H⁵

3.71, C₅H₅

4.25, br, m

4.58, br, m

3.28, br, m

3.60, br, m

3.45, t, ꢀOH

4.02, H³

n

4.30, H⁴

4.61, H⁵

^aLabelling of the atoms refers to the schemes shown above.

^bBroad and partially overlapped with the signal due to the protons of the C₅H₅ring.

^{c 3}J(¹⁹⁵PtꢀH)=85 Hz.

^{d 3}J(¹⁹⁵PtꢀH)=17 Hz.

^eSee text.

^fThe protons of the ꢀCH₂ꢀ moieties are diastereotopic.

^gPartially overlapped.

^hIn this case the spectrum was recorded in the presence of py-d₅.

ⁱOverlapped by the multiplet due to the protons of the ꢀCH₂ꢀ group.

^jDoublet due to phosphorus coupling: ³J(PꢀH)=8 Hz (for 6) and 21 Hz (for 7).

^kTwo additional multiplets due to the protons of the PꢀCH₂ꢀ groups of the dppe were also observed at 2.06 and 2.60 ppm.

^lThe signals due to the protons of the ethyl groups appeared as four triplets (at 1.60, 1.19, 1.05 and 0.93 ppm, ꢀCH₃protons) and four

multiplets centered at: 2.80, 2.45, 2.37 and 2.20 ppm (ꢀCH₂ꢀ).

^mThe signal due to the proton of the ꢀOH group was not observed.

ⁿThe resonance of the protons of the ꢀOCH₃fragments appeared as four singlets at 3.99, 3.95, 3.86 and 3.45 ppm.

90

C. Lo´pez et al. / Journal of Organometallic Chemistry 598 (2000) 87–102

Table 2

a

¹³C-NMR data (in ppm) for the free ligand (1) and for the platinum(II) (2) and palladium(II) complexes under study

Complex

Ferrocenyl moiety

ꢀCHꢁNꢀ

\NꢀCH₂ꢀ

ꢀCH₂ꢀ

Others

–

1

69.18, C₅H₅

70.58, C², C⁵

68.59, C³, C⁴

70.42, C₅H₅

73.94, C², C⁵

73.01, C³, C⁴

70.18, C₅H₅

70.22, C₅H₅

72.90

163.24

63.60

62.25

b

2

171.40

67.76

59.96

43.18, SꢀCH₃

3 ^c

171.56

171.36

67.68

67.31

60.02

59.57

–

72.08

73.08

72.90

4

70.22, C₅H₅

74.99, C²

68.85, C³

71.52, C⁴

73.08, C⁵

70.17, C₅H₅

87.02, C¹

102.91, C²

66.45, C³

69.15, C⁴

68.37, C⁵

70.31, C₅H₅

89.39, C¹

102.91, C²

68.85, C³

62.91, C⁴

71.60, C⁵

70.74, C₅H₅

89.58, C¹

99.69, C²

70.52, C³

71.58, C⁴

73.41, C⁵

71.90, C₅H₅

86.55, C¹

88.32, C²

70.30, C³

73.17, C⁴

75.59, C⁵

68.97, C₅H₅

74.85, C²

68.06, C³

70.98, C⁴

72.78, C⁵

171.58

173.30

67.30

63.03

59.56

59.43

–

6 ^d

e

7 ^f

178.78

165.82

165.93

173.46

62.91

63.61

64.10

65.11

59.01

63.05

62.00

61.47

g

9

12.82

14.30

14.86

17.91

h

i

j

10

11

k

^aLabelling of the atoms refers to the schemes shown at the top of Table 1.

^{b 2}J(PtꢀC)=22.1 Hz.

^cTwo superimposed spectra were detected in this case, due to the inhibition of the rotation around the PdꢀN bond (see text).

^dThe signal due to the C²carbon appears as a doublet due to phosphorus coupling.

^eFour additional doublets (centered at ca. 134.74, 131.50, 130.40 and 128.02 ppm) due to the four types of carbon atoms of the phenyl rings

of the triphenylphosphine ligand.

^fThe signals due to the carbons: C¹, C³and ꢀNꢀCH₂ꢀ appeared as doublets due to phosphorus coupling centered at the values given, and a

doublet of doublets was observed for the carbons of the ꢀCH₂ꢀCH₂ꢀ fragment of the dppe.

^gSelected additional data: 30.60 and 27.20, CH₂ꢀ of the dppe.

^hThe signals due to the ꢀCH₂ꢀ groups of the h³-butadienyl unit appeared at 35.29, 24.98, 24.42 and 21.89 ppm.

ⁱAdditional signals at 144.89, 136.88, 177.29 and 108.49 ppm.

^jAdditional signals at: 110.15, 124.64, 126.24, 126.38, 126.80, 127.48, 127.56, 127.82, 127.90, 128.046, 130.95, 134.39, 137.75, 139.72, 140.19,

145.25 and 153.60 ppm.

^kThe signals due to the carbons of the ꢀOCH₃moieties appeared at: 59.65, 59.43, 58.81 and 52.85 ppm.

C. Lo´pez et al. / Journal of Organometallic Chemistry 598 (2000) 87–102

91

derivatives [28]. The two pentagonal rings are planar¹,

nearly parallel (tilt angle: 0.59°) and deviate −3.4°

from the ideal eclipsed conformation.

assumed that compound 2 also corresponds to the

trans-isomer.

The reaction of the ferrocenyl Schiff base 1 with a

stoichiometric amount of Na₂[PdCl₄] in methanol at

room temperature produced an orange solid. Its char-

acterization data based on elemental analyses and

IR and NMR spectroscopic data were consistent with

those expected for [Pd{[(h⁵-C₅H₄)ꢀCHꢁNꢀCH₂ꢀ

CH₂ꢀOH]Fe(h⁵-C₅H₅)}₂Cl₂] (3) (Scheme 1). This com-

pound was obtained in higher yield when the reaction

was performed using a two-fold excess of the imine 1.

However, when the reaction was carried out in

the presence of a stoichiometric amount of Na(CH₃-

COO)·3H₂O, the di-m-chloro-bridged cyclopalladated

complex: [Pd{[(h⁵-C₅H₃)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH]Fe(h⁵-

C₅H₅)}(m-Cl)]₂(4) was obtained (Scheme 2).

2.2. Reacti6ity of 1 6ersus platinum(II) and

palladium(II) salts

When ligand 1 was treated with cis-[PtCl₂(dmso)₂] in

reﬂuxing methanol for 3 h, a red solution was obtained.

Concentration of this solution on a rotary evaporator

to ca. 10 cm³produced the precipitation of a red solid,

which was identiﬁed according to elemental analy-

ses and infrared and ¹H-NMR data as [Pt{[(h⁵-

C₅H₄)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH]Fe(h⁵- C₅H₅)}Cl₂(dmso)]

(2) (Scheme 1).

Quite recently, Wu et al. [29] reported that the reac-

tion of the ferrocenyl ketimine: [(h⁵-C₅H₅)Fe{(h⁵-

C₅H₄)ꢀC(CH₃)ꢁNꢀC₆H₅}] with cis-[PtCl₂(dmso)₂] in

reﬂuxing methanol produced [Pt{[(h⁵-C₅H₄)ꢀC(CH₃)ꢁ

NꢀC₆H₅]Fe(h⁵-C₅H₅)}Cl₂(dmso)] (2%). The structural

characterization of (2%) revealed that the two chlorine

groups are in a trans-arrangement. On this basis we

This compound arises from the activation of

a

|(C_{sp ,ferrocene}ꢀH) bond and contains two ﬁve-membered

2

palladacycles. These results are consistent with those

reported previously for related ferrocenyl aldimines

and ketimines, for which the activation of the

s(PdꢀC_{sp ,ferrocene}) required the presence of a base such

2

as NaCH₃COO [24,25,30,31].

Complex 4 undergoes bridge-splitting reactions in the

presence of deuterated pyridine (py-d₅) in CDCl₃or

triphenylphosphine (PPh₃) in benzene to give the corre-

sponding monomeric derivatives: [Pd{[(h⁵-C₅H₃)ꢀ

CHꢁNꢀCH₂ꢀCH₂ꢀOH]Fe(h⁵-C₅H₅)}Cl(L)], with L=

py-d₅(5) or PPh₃(6) (Scheme 2), in which the ligand

acts as a monoanionic (C,N)⁻group.

When 1,2-bis(diphenylphosphino)ethane was added

to a CH₂Cl₂suspension of 4 at room temperature (ca.

20°C), dissolution of the starting material immediately

took place. Concentration of the resulting mixture on a

rotary evaporator to ca. 5 cm³followed by the slow

evaporation of the solution at room temperature (ca.

20°C) produced a red microcystalline material. Its char-

acterization data, based on elemental analyses and in-

frared and NMR {¹H, ¹³C and ³¹P} spectroscopies

were consistent with those expected for: [Pd{[(h⁵-

C₅H₃)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH]Fe(h⁵- C₅H₅)}(dppe)]Cl

(7) (Scheme 2).

Fig. 1. Molecular structure and atom numbering scheme for the

ligand: [(h⁵-C₅H₅)Fe{(h⁵-C₅H₄)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH}] (1).

Table 3

5

,

Selected bond lengths (A) and angles (°) for [(h -C₅H₅)Fe{(h -

C₅H₄)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH}] (1) ^a

Bond lengths

NꢀC(11)

OꢀC(13)

1.252(5)

1.389(6)

1.496(7)

1.398(21)

NꢀC(12)

C(10)ꢀC(11)

FeꢀC_ring

1.467(6)

1.459(6)

2.017(5)

b

C(12)ꢀC(13)

2.3. Study of the reacti6ity of the

b

|(PdꢀC_{sp , ferrocene}) bond in [Pd{[(p⁵-C₅H₃)ꢀ

CꢀC_ring

2

CHꢁNꢀCH₂ꢀCH₂ꢀOH]Fe(p⁵-C₅H₅)}(v-Cl)]₂(4)

Bond angles

C(6)ꢀC(10)ꢀC(11) 127.9(4)

C(9)ꢀC(10)ꢀC(11)

C(11)ꢀNꢀC(12)

C(12)ꢀC(13)ꢀO

123.7(4)

117.6(4)

109.2(4)

C(10)ꢀC(11)ꢀN

NꢀC(12)ꢀC(13)

122.9(4)

109.5(4)

Cyclopalladated complexes are particularly relevant

due to the high reactivity of the s(PdꢀC) bond, which

has provided new methods for the syntheses of organic

and organometallic compounds [32–34]. Most of these

reactions are based on the insertion of small molecules

(mainly alkynes and to a lesser extent, isonitriles, al-

kenes or CO) into the s(PdꢀC) bond. On this basis,

complex 4 appeared to be a good candidate for the

^aEstimated S.D. values in parenthesis.

^bAverage values for the ferrocenyl moiety.

¹The least-squares equation of the planes deﬁned by the sets of

atoms [C(1)ꢀC(5)] and [C(6)ꢀC(10)] are the following: (0.6873)XO+

(0.6835)YO+(−0.2456)ZO=2.6326

(0.6813)YO+(−0.2557)ZO=5.8573.

and

(0.6859)XO+

study of the reactivity of the s(PdꢀC_{sp ,ferrocene}) bond

2

92

C. Lo´pez et al. / Journal of Organometallic Chemistry 598 (2000) 87–102

Scheme 2. (i) Na₂[PdCl₄], Na(CH₃COO)·3H₂O in methanol at room temperature. (ii) L=py-d₅(in (CDCl₃) or PPh₃in benzene at room

temperature. (iii) 1,2-Bis(diphenylphosphino)ethane (dppe) in CH₂Cl₂at room temperature.

versus tert-butylisonitrile or the alkynes RꢀCꢂCꢀR (with

R=Et, Ph or CO₂Me), which differ in the electronic and

steric nature of the substituents [35].

[Pd{5%-OCH₃ꢀC₆H₃ꢀCHꢁNꢀC₆H₄-4-CH₃}(m-Cl)]₂(Ia)

which produces the ketimine (IIa in Scheme 3(B)) under

identical experimental conditions [34]. These ﬁndings

suggest that compound 4 is less prone to undergo the

insertion of tert-butylisonitrile than [Pd{5%-OCH₃ꢀ

C₆H₃ꢀCHꢁNꢀC₆H₄-4-CH₃}(m-Cl)]₂(Ia).

In contrast with these results, when complex 4 was

treated with the alkynes RꢀCꢂCꢀR (with R=Et, Ph or

CO₂Me) in a 1:4 molar ratio in reﬂuxing chloroform for

1.5 h, the cyclopalladated complexes of general formula:

[Pd{[(RꢀCꢁCꢀR)₂(h⁵- C₅H₃)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH]-

Fe(h⁵-C₅H₅)}Cl] (with R=Et (9), Ph (10) or CO₂Me

(11)) were isolated (Scheme 4), and no evidence of the

formation of any other palladium(II) complex was de-

tected by NMR spectroscopy.

In a ﬁrst attempt to study the reactivity of the

cyclopalladated complex 4 versus the tert-butylisonitrile,

the procedure described by Albinati and co-workers [34]

was used. This method consists of the reaction of the

di-m-chloro-bridged cyclopalladated derivative with an

excess of the isonitrile and 1,2-bis(diphenylphos-

phino)ethane in CH₂Cl₂at room temperature. When the

reaction was carried out using compound 4 two products

were isolated (Scheme 3(A)). The characterization data

of one of them was identical to those obtained for

complex 7, which contains a ﬁve-membered metallacycle

where the diphosphine acts as a neutral (P,P%) bidentate

ligand. Elemental analyses and NMR data of the second

component conﬁrmed those expected for: [Pd{[(h⁵-C₅H₃)

ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH]Fe(h⁵-C₅H₅)}Cl(CNC-Me₃)]

(8). This complex arises from the bridge-splitting reaction

and the coordination of the isonitrile to the palladiu-

m(II). The X-ray crystal structure of compound 8 (see

below) conﬁrms these results. Compound 8 can be

obtained in higher yield by treatment of 4 with a two-fold

excess of the isonitrile in CH₂Cl₂.

Compounds 9–11 arise from the bis(insertion) of the

corresponding alkyne into the s(PdꢀC_{sp ,ferrocene}) and

2

contain a nine-membered palladacycle. The X-ray crystal

structure of [Pd{[(PhꢀCꢁCꢀPh)₂(h⁵-C₅H₃)ꢀCHꢁNꢀ

CH₂ꢀCH₂ꢀOH]Fe(h⁵-C₅H₅)}Cl] (10) described below

conﬁrms these results.

It is widely accepted that the nature of the ﬁnal product

formed in the reaction of alkynes and cyclopalladated

complexes containing s(PdꢀC_{sp ,aryl}) bonds depends on

2

The results obtained in the reaction of 4 with tert-

butylisonitrile are in contrast with those reported for

a wide variety of factors including: (a) the nature of the

substituents (R) of the alkyne; (b) the structure and

C. Lo´pez et al. / Journal of Organometallic Chemistry 598 (2000) 87–102

93

Scheme 3. (i) CNCMe₃and dppe in CH₂Cl₂at room temperature. (ii) SiO₂, column chromatography, using CHCl₃as eluent.

Scheme 4. (i) RꢀCꢂCꢀR in reﬂuxing CHCl₃, 1.5 h, followed by SiO₂column chromatography, using a 100:1 CHCl₃–CH₃OH mixture as eluant.

nature of the metallated ligand; (c) the stoichiometry;

(d) the lability of the PdꢀN bond; and (e) the remaining

ligands bound to the palladium [32]. In the reactions

under study, the nature of the sub stituent of the alkyne

was the only variable introduced in all the reactions

[35]. It has been postulated that for the insertion of

though the R groups of the three alkynes used in this

study have different electronic properties [35], the for-

mation of the bis(insertion) products is strongly favored

in all cases.

In addition, it is also interesting to compare the

results obtained in the reaction of 4 with the alkyne:

MeO₂CꢀCꢂCꢀCO₂Me with those reported for the cy-

clopalladated complexes: [Pd{RꢀC₆H₃ꢀCHꢁNꢀC₆H₄-4-

CH₃}(m-CH₃COO)]₂(I) (with R=5-NO₂(Ib), 4-NO₂

(Ic), 5-Cl (Id) or 4-Cl (Ie)) (Scheme 5). Addition of an

excess of the alkyne to the bridged acetate dimers

containing electron-withdrawing R groups (Ib–e) pro-

alkynes into the s(PdꢀC_{sp ,aryl}) bond of cyclopalladated

2

complexes containing N,N-dimethylbenzylamines, the

electron-donating or electron-withdrawing nature of the

substituents (R) of the alkynes appears to play a crucial

role in determining the nature of the ﬁnal product (a

mono(insertion) or a bis(insertion) derivative) [36]. Al-

94

C. Lo´pez et al. / Journal of Organometallic Chemistry 598 (2000) 87–102

Scheme 5. (i) MeO₂CꢀCꢂCꢀCO₂Me in methanol, 40°C, 12 h.

duced [Pd{RꢀC₆H₃ꢀCHꢁNꢀC₆H₄-4-CH₃}{OC(OCH₃)ꢀ

C(OCH₃)ꢁC(COOCH₃)}] (IIIb–e) in fairly good yields

(in the range: 70–90%) [34]. The nature of compounds

III, which contain a ﬁve-membered palladacycle and a

six-membered chelate ring, is markedly different from

that of 11 in which a nine-membered palladacycle is

formed through the bis(insertion) of the MeO₂CꢀC

¹H-NMR spectroscopic data for compounds under

study are summarized in Table 1. The ¹H-NMR spectrum

of 2 showed the typical pattern of monosubstituted

ferrocene derivatives: three signals of relative intensities

2:2:5 in the range 5.00–3.50 ppm. In contrast with these

results, the spectrum of 3 exhibited higher complexity

and some of the signals appeared in duplicate, which

suggested the existence of two isomeric species in solu-

tion. In an initial attempt to explain the complexity of

the ¹H-NMR spectrum, a molecular model of the trans-

isomer of 3 was constructed. Its manipulations revealed

that a coplanar arrangement between the ‘PdCl₂’ frag-

ment and the backbone of the imine group is not possible

since such an orientation would involve short contacts

between one of the chlorines and the ortho-hydrogen of

the C₅H₄ring. In order to conﬁrm these facts, the

pm3(tm) program included in the ^SPARTANpackage [37]

was used. For this arrangement of groups, the estimated

Cl···H_orthodistance obtained by the program is too small

ꢂCꢀCO₂Me into the s(PdꢀC_{sp ,ferrocene}) bond. The differ-

2

ences observed in the reactivity of compounds I and 4

versus this alkyne may be related to the nature of the

metallated carbon (C_{sp ,aryl}in I and C_{sp ,ferrocene}in 4), the

2

different lability of the PdꢀN bond, or even the remaining

ligands bound to the palladium. All these factors may

modify the net charge of the metallated carbon. Accord-

ing to the literature, this factor plays a crucial role in the

reactions of cyclopalladated complexes with alkynes [36].

2.4. Characterization of the platinum(II) and

palladium(II) compounds

,

(0.66 A). A nearly orthogonal orientation of the ‘PdCl₂’

fragment and the imine groups signiﬁcantly reduces the

steric hindrance. Consequently, this steric repulsion pre-

cludes free rotation around the PdꢀN bond. Thus, it

Compounds 2–6 were characterized by elemental

analyses and infrared and NMR spectroscopies. Except

for compound 5, which was prepared and characterized

in situ, for the remaining complexes, the elemental

analyses (see Section 3) are consistent with the proposed

formulae. The most outstanding feature observed in the

IR spectra of these complexes is the band due to the

stretching of the imine group, which appears in the range:

1560–1640 cm⁻¹. It is noteworthy that in the ﬁve-mem-

bered cyclopalladated complexes 4, 6–8 this band ap-

pears strongly shifted to lower wavenumbers than in the

coordination complexes 2, 3.

1

would seem that the complexity of the H-NMR spec-

trum might be due to the presence of rotameric species

(Fig. 2(A and B)), which differ in the relative arrange-

ment of the ‘Fe(h⁵-C₅H₅)’ moieties in each one of the

ligands.

The ¹³C{¹H}-NMR data (see below) are consistent

with this hypothesis. However, it should be noted that

for compounds: trans-[Pd(R¹C(R²)ꢁNꢀNR³R⁴)Cl₂]

(where R¹=H, Me, Et; R²=Me, Et or ⁱPr, R³=Me or

Et and R⁴=Me} [38] and trans-[Pd{(h⁵-C₅H₅)Fe{(h⁵-

C. Lo´pez et al. / Journal of Organometallic Chemistry 598 (2000) 87–102

95

C₅H₄)ꢀCHꢁNꢀNMe₂}Cl₂] (3%) [39] the complexity of the

NMR spectra was also interpreted in terms of the

presence of rotameric species in solution. As well as

this, the X-ray crystal structure of (3%) conﬁrmed a

nearly orthogonal arrangement of the imine fragments

versus the ‘PdCl₂’ moiety [39].

1

The H-NMR spectra of the cyclopalladated deriva-

tives 4–11 showed the typical pattern of 1,2-disubsti-

tuted ferrocene complexes, i.e. four signals of relative

intensities 1:1:1:5 in the range 3.50–4.80 ppm.

¹³C-NMR spectroscopic data are presented in Table

2; the signals were assigned on the basis of 2D-het-

Fig. 4. Molecular structure and atom numbering scheme for:

[Pd{[(h⁵- C₅H₃)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH]Fe(h⁵- C₅H₅)}Cl(CNCMe₃)]

(8)

eronuclear {¹H–¹³C}-NMR experiments. The ³¹P{¹H}-

NMR spectrum of 6 showed a singlet at 37.40 ppm.

The position of this signal is consistent with a trans

arrangement between the PPh₃ligand and the imine

nitrogen [24,26,31,40–42]. For compound 7, which con-

tains two phosphorus atoms in different environments,

the ³¹P{¹H}-NMR spectra showed two doublets cen-

tered at 48.04 and 62.38 ppm in close accord with the

results obtained for [Pd{[(h⁵-C₅H₃)ꢀCHꢁNꢀR]Fe{(h⁵-

C₅H₅)}(dppe)]Cl, with R=phenyl or benzyl groups

[24].

Fig. 2. Schematic view of the two isomers A and B of 3 present in

solution. In the ﬁgure the dashed lines indicate that they are in a

lower plane. The main difference between the two isomer is found in

the relative orientation of the ‘Fe(h⁵-C₅H₅)’ moieties in each one of

the ligands. In A the two ‘Fe(h⁵-C₅H₅)’ fragments are on the same

side of one of the chlorines; while in B each one of the ‘Fe(h⁵-C₅H₅)’

moieties is facing a different chlorine, and in this case the whole

molecule is centrosymmetric.

Compound 2 was also characterized by ¹⁹⁵Pt{¹H}-

NMR spectroscopy. The spectrum showed a complex

signal at −3025 ppm. The position of the signal

is consistent with the ¹⁹⁵Pt chemical shifts reported

for cis-[PtCl₂(NH₃)(dmso)] (l= −3046 ppm [43]),

[Pt₂{Fe[(h⁵-C₅H₄)ꢀCH₂ꢀN(CH₃)₂]₂}Cl₄(dmso)₂]

(l=

−3006 ppm [44]) or related platinum(II) complexes

containing a (NSCl₂) environment around the platinum

[43,45,46]. The complexity of the signal could be due to

the coupling between the platinum(II) and the protons

of the NꢀCH₂ꢀ group and/or of the methyl groups of

the coordinated dmso ligand.

Compounds [Pd{[(h⁵-C₅H₃)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH]-

Fe(h⁵-C₅H₅)}Cl(PPh₃)] (6) and [Pd{[(h⁵-C₅H₃)ꢀ

CHꢁNꢀCH₂ꢀCH₂ꢀOH]Fe(h⁵-C₅H₅)}Cl(CNCMe₃)] (8)

were also characterized by X-ray diffraction. The

molecular structure of these complexes together with

the atom labeling schemes are shown in Figs. 3 and 4,

respectively. A selection of bond lengths and angles is

presented in Tables 4 and 5.

These structures consist of discrete molecules of

[Pd{[(h⁵-C₅H₃)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH]Fe(h⁵-C₅H₅)}-

Cl(PPh₃)] (in 6) or [Pd{[(h⁵-C₅H₃)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀ

Fig. 3. Molecular structure and atom numbering scheme for:

[Pd{[(h⁵-C₅H₃)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH]Fe(h⁵-C₅H₅)}Cl(PPh₃)] (6).

96

C. Lo´pez et al. / Journal of Organometallic Chemistry 598 (2000) 87–102

OH]Fe(h⁵-C₅H₅)}Cl(CNCMe₃)] (in 8) separated by van

der Waals contacts. The palladium is bound to the

chlorine, the imine nitrogen, the ortho-carbon of the

ferrocenyl fragment (C(9) in 6 or C(6) in 8) and the

phosphorus of the PPh₃ligand in 6 or the terminal

carbon atom of the isonitrile (C(14)) in 8 in a slightly

distorted square-planar environment²).

In the two cases, the metallacycles are practically

planar³and contain the \CꢁNꢀ functional group, thus

conﬁrming the endo-type structure predicted by ¹H- and

¹³C-NMR spectroscopies. The palladacycles are practi-

cally co-planar with the C₅H₃ring of the ferrocenyl

moiety (the dihedral angle formed by the normals to

their main planes is 4.71° in 6 and 3.57° in 8). The

,

\CꢁNꢀ bond distance (1.278(5) A in 6 or 1.272(6) A

in 8) is similar to the distances found in related ﬁve-

membered palladacycles with s(PdꢀC_{sp ,ferrocene}) bonds

2

and is slightly greater, if signiﬁcant, than that of the

,

free ligand (1.252(5) A). The ferrocenyl- and the

Table 4

Selected bond lengths (A) and angles (°) for [Pd{[(h⁵-C₅H₃)ꢀ

Fig. 5. Molecular structure and atom numbering scheme for:

[Pd{[(PhꢀCꢁCꢀPh)₂(h⁵-C₅H₃)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH]Fe(h⁵-C₅H₅)}-

Cl] (10).

,

CHꢁNꢀCH₂ꢀCH₂ꢀOH]Fe(h⁵-C₅H₅)}Cl(PPh₃)] (6) ^a

Bond lengths

PdꢀP

PdꢀN

C(9)ꢀC(10)

NꢀC(11)

C(12)ꢀC(13)

2.240(2)

2.135(4)

1.447(6)

1.278(5)

1.513(7)

2.043(11)

PdꢀCl

2.375(2)

1.998(4)

1.424(6)

1.457(6)

1.395(6)

1.413(20)

PdꢀC(9)

C(10)ꢀC(11)

NꢀC(12)

C(13)ꢀO

CH₂ꢀCH₂OH groups are in a trans-arrangement, thus

indicating that the ligand retains the E-form during the

reaction.

b

In compound 8 the isonitrile group is bound to the

palladium through the terminal carbon (C(14)) and the

fragments: PdꢀC(14)ꢀC(15) and C(14)ꢀN(2)ꢀC(15) are

practically linear (bond angles 176.2(5) and 174.4(6)°,

respectively). The torsion angle PdꢀC(14)ꢀN(2)ꢀC(15) is

−49.82°.

FeꢀC_ring

CꢀC_ring

Bond angles

NꢀPdꢀC(9)

NꢀPdꢀP

80.9(2)

170.24(9)

92.31(11)

113.1(3)

111.0(3)

120.0(4)

109.7(4)

PꢀPdꢀC(9)

ClꢀPdꢀC(9)

PꢀPdꢀCl

PdꢀNꢀC(12)

C(10)ꢀC(11)ꢀN

NꢀC(12)ꢀC(13)

92.21(13)

171.44(11)

95.14(7)

126.8(3)

117.3(4)

112.5(4)

NꢀPdꢀCl

PdꢀNꢀC(11)

PdꢀC(9)ꢀC(10)

C(11)ꢀNꢀC(12)

C(12)ꢀC(13)ꢀO

Table 5

Selected bond lengths (A) and angles (°) for [Pd{[(h⁵-

,

^aEstimated S.D. values in parenthesis.

^bAverage value for the ferrocenyl moiety.

C₅H₃)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH]Fe(h⁵-C₅H₅)}Cl(CNCMe₃)] (8) ^a

Bond lengths

PdꢀC(14)

PdꢀN

C(9)ꢀC(10)

NꢀC(11)

1.991(5)

2.080(4)

1.414(7)

1.272(6)

1.513(7)

1.131(6)

1.472(12)

1.453(12)

1.39(2)

PdꢀCl

PdꢀC(6)

C(10)ꢀC(11)

NꢀC(12)

C(13)ꢀO

N(2)ꢀC(15)

C(15)ꢀC(17)

FeꢀC_ring

2.394(2)

1.951(5)

1.423(6)

1.451(5)

1.411(7)

1.472(9)

1.392(12)

2.02(2)

²For 6: the least-squares equation of the plane deﬁned by the

atoms Pd, Cl, P, N and C(9) is: (−0.1453)XO+(0.8876)YO+

(−0.4371)ZO= −3.3167. The deviations from the mean plane are:

,

Pd, +0.014; P, −0.100; Cl, +0.086; and N, −0.012 A. For 8: the

C(12)ꢀC(13)

C(14)ꢀN(2)

C(15)ꢀC(16)

C(15)ꢀC(18)

least-squares equation of the plane deﬁned by the atoms Pd, Cl, N(1),

C(8) and C(14) is: (−0.6051)XO+(0.7082)YO+(−0.3638)ZO=

10.1058. The deviations from the mean plane are: Pd, +0.0297; Cl,

b

,

−0.0354; N(1), +0.0271; C(8), −0.0483; and C(14), 0.0269 A.

b

CꢀC_ring

³For 6: The least-squares equation of the plane deﬁned by the

atoms Pd, N, C(9), C(10) and C(11) is: (−0.1045)XO+

(0.9248)YO+(−0.3658)ZO= −2.3622. The deviations from the

mean plane are: Pd, +0.0172; N, −0.0.0161; C(9), +0.0231; C(10),

Bond angles

NꢀPdꢀC(6)

NꢀPdꢀC(14)

NꢀPdꢀCl

81.1(2)

169.6(2)

92.31(11)

113.1(3)

C(14)ꢀPdꢀC(6)

ClꢀPdꢀC(9)

PꢀPdꢀCl

92.21(13)

171.44(11)

95.14(7)

,

−0.0180; and C(10), −0.0040 A. For 8: the least-squares equation

of the plane deﬁned by the atoms Pd, N(1), C(8), C(10) and C(11) is:

(−0.6634)XO+(0.6894)YO+(0.2905)ZO=9.4569. The deviations

from the mean plane are: Pd, −0.0268; N(1), 0.0729; C(8), +0.0303;

PdꢀNꢀC(11)

PdꢀNꢀC(12)

126.8(3)

^aEstimated S.D. values in parenthesis.

^bAverage value for the ferrocenyl moiety.

,

C(10), −0.0345; and C(14), −0.0419 A.

C. Lo´pez et al. / Journal of Organometallic Chemistry 598 (2000) 87–102

97

after referred to as ) in a distorted square planar

environment. The deviations from the mean plane⁵) are

as follows: Cl(1), 0.1534; N, −0.1528; C(35), −0.2036

Bond lengths and angles in the ferrocenyl fragment

are very similar to those reported for other ferrocene

derivatives [28]. The two pentagonal rings are planar⁴),

nearly parallel (tilt angles: 1.03 and 4.27° for 6 and 8,

respectively) and they deviate from the ideal eclipsed

conformation by −3.74° in 6 and by 1.75° in 8. The

long distance between the Fe(II) and the Pd(II) ions

,

and , 0.2031 A. The PdꢀN, PdꢀCl(1) and PdꢀC(35)

bond lengths are similar to those found in ﬁve-mem-

bered cyclopalladated complexes [14,21,24–28,40,41].

The palladium is symmetrically bound to the carbons

,

C(14) and C(21) (PdꢀC(14): 2.085(4) A and PdꢀC(21):

,

(3.5635(3) A in 6 or 3.5020(3) A in 8) suggests that

there is no direct interaction.

,

2.085(4) A) and the angle C(14)ꢀPdꢀC(21) is 39.6(2)°.

The C(14)ꢀC(21) double bond forms a dihedral angle of

70.97° with the coordination plane of the complex. The

The molecular structure of compound 10 and the

atom labeling scheme are shown in Fig. 5, and a

selection of bond lengths and angles is presented in

Table 6.

The structure consists of discrete molecules of

[Pd{[(PhꢀCꢁCꢀPh)₂(h⁵-C₅H₃)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH]-

Fe(h⁵-C₅H₅)}Cl] separated by van der Waals contacts

and also contains a molecule of CH₂Cl₂as solvate. The

palladium is tetracoordinated bound to a chlorine

(Cl(1)), the nitrogen, C(35) and the middle point of the

segment deﬁned by the atoms C(14) and C(21) (here-

,

C(14)ꢀC(21) bond length is clearly longer (1.427(6) A)

,

than the C(28)ꢀC(35) double bond (1.294(5) A), and

this difference can be attributed to the different type of

coordination of the two groups to the palladium atom

(h²and h¹, respectively).

The complex contains a [5,9] bicyclic system, which

arises from the fusion of the substituted pentagonal

ring of the ferrocenyl moiety and a nine-membered

palladacycle formed by the set of atoms: Pd, N, C(11),

C(9), C(10), C(14), C(21), C(28) and C(35).

The \CꢁNꢀ functional group is contained in the

nine-membered metallacycle, thus conﬁrming its endo-

structure. The imine ligand has an anti-conformation

(E-form) as reﬂected in the torsion angle: C(9)ꢀC(11)ꢀ

NꢀC(12): 174.1(2)°. The distance between the two metal

Table 6

5

,

Selected bond lengths (A) and angles (°) for [Pd{[PhꢀCꢁCꢀPh)₂(h -

C₅H₃)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH]Fe(h⁵-C₅H₅)}Cl] (10) ^a

Bond lengths

,

atoms (4.263(3) A) is clearly longer than that found in

the ﬁve-membered cyclopalladated complexes

PdꢀC(14)

PdꢀC(28)

Pdꢀ

2.085(4)

2.522(5)

1.9791(4)

2.128(4)

1.439(6)

1.326(6)

1.427(6)

1.294(5)

1.37(3)

PdꢀC(21)

PdꢀC(35)

PdꢀCl(1)

NꢀC(11)

2.085(4)

1.987(5)

2.215(2)

1.227(5)

1.471(7)

1.452(6)

1.470(6)

1.99(3)

6

,

(3.5635(3) A) and 8 (3.5020(3) A), and consequently

there is no direct interaction between Pd and Fe.

The average CꢀC bond length in the two pentagonal

rings (1.37(2) A) is similar to the values reported for

other ferrocene derivatives [28]. The FeꢀC(ring) bond

PdꢀN

NꢀC(12)

C(13)ꢀO

C(14)ꢀC(21)

C(28)ꢀC(35)

C(12)ꢀC(13)

C(10)ꢀC(14)

C(21)ꢀC(28)

,

b

FeꢀC_ring

b

CꢀC_ring

,

distance ranges from 1.941(5) to 2.049(4) A. The

longest bond distance corresponds to the FeꢀC(10)

bond which is directly involved in the insertion process.

The two pentagonal rings are parallel (tilt angle: 3.79°)

and their relative orientation deviates by 22.97° from

the ideal eclipsed conformation.

Bond angles

NꢀPdꢀCl(1)

NꢀPdꢀC(35)

NꢀPdꢀC(14)

C(21)ꢀPdꢀCl(1)

90.36(12) NꢀPdꢀC(28)

136.55(14)

103.7(2)

153.36(2)

96.9(2)

165.1(2)

96.9(2)

NꢀPdꢀC(21)

C(14)ꢀPdꢀCl(1)

C(35)ꢀPdꢀCl(1)

103.7(2)

^aEstimated S.D. values in parenthesis.

^bAverage value for the ferrocenyl moiety.

The phenyl substituents on the double bond

C(14)ꢀC(21) are trans to each other, and those of the

C(28)ꢀC(35) are cis. This arrangement of the four

phenyl groups is consistent with the common distribu-

tion of substituents of h³-butadienyl fragments in nine-

membered metallacycles formed by bis(insertion)

processes [47–52]. The X-ray crystal structure of 10

shows that the C(14)ꢀC(21) bond of the butadienyl

fragment is located below the plane deﬁned by the

atoms N, C(11) and opposite to the iron center and the

C₅H₅ring of the ferrocenyl moiety, and that the phenyl

ring at the C(14) atom is oriented towards the unsubsti-

tuted pentagonal ring.

⁴For 6: the least-squares equation of the plane deﬁned by the

set of atoms [C(1)ꢀC(5)] is: (−0.1264)XO+(0.9516)YO+

(−0.2801)ZO=1.8224. The deviations from the mean plane are:

C(1), −0.0005; C(2), +0.0019; C(3), −0.0025; C(4), 0.0022; C(5):

,

−0.0010 A. The least-squares equation of the plane deﬁned by the

set of atoms [C(6)ꢀC(10)] is: (−0.1103) XO+(0.9512) YO+

(−0.2882) ZO= −1.5156. The deviations from the mean plane are:

C(6), −0.0001; C(7), 0.0031; C(8), −0.0048; C(9), 0.0047; and C(10),

,

−0.0028 A. For 8: the least-squares equation of the plane deﬁned by

the set of atoms [C(1)ꢀC(5)] is: (−0.7515)XO+(0.5794)YO+

(0.3153)ZO=5.1555. The deviations from the mean plane are

the followings: C(1), +0.021; C(2), −0.011; C(3), −0.002; C(4),

,

+0.015; and C(5), −0.020 A. The least-squares equation of the

plane deﬁned by the set of atoms [C(6)ꢀC(10)] is: (−0.7161) XO+

(0.6373) YO+(0.2847) ZO=8.9222. The deviations from the mean

plane are: C(6), −0.024; C(7), +0.001; C(8), −0.001; C(9), −0.001;

⁵The least-squares equation of the plane deﬁned by the atoms:

Cl(1), N, C(35) and the middle point () of the segment deﬁned by

C(14) and C(21) is: (−0.2417)XO+(0.7099)YO+(0.6616)ZO=

4.8195.

,

and C(10), −0.002 A.

98

C. Lo´pez et al. / Journal of Organometallic Chemistry 598 (2000) 87–102

Table 7

sequence 4B8B6. These ﬁndings are consistent with

data reported for related cyclopalladated complexes

derived from N-donor ferrocenyl units for which the

di-m-chloro derivatives were less resistant to oxidation

Summary of the electrochemical data: anodic (E_pa) and cathodic (E_pc

)

potentials (in mV) for compounds under study ^a

Compound

E_paE_pc

98 30

than their analogues of general formula [Pd(C N)-

[(h⁵-C₅H₅)Fe{(h⁵-C₅H₄)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH}] (1)

Cl(PR₃)] [14,23,41]. For compounds 9–11 the oxidation

occurs at higher potentials, thus indicating that the

nine-membered cyclopalladated complexes are more re-

sistant to oxidation than the free ligand 1 and the

ﬁve-membered palladacycles 4, 6 and 8. For complex

11, no reduction peak was detected in the reverse scan,

thus suggesting that the oxidation is electrochemically

irreversible.

[Pd{[(h⁵-C₅H₄)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH]Fe(h⁵-C₅H₅)}₂- 304 230

Cl₂] (3)

[Pd{[(h⁵-C₅H₃)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH]Fe(h⁵-C₅H₅)}-

(m-Cl)]₂(4)

57 −43

[Pd{[(h⁵-C₅H₃)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH]Fe(h⁵-C₅H₅)}- 108

Cl(PPh₃)] (6)

8

[Pd{[(h⁵-C₅H₃)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH]Fe(h⁵-C₅H₅)}-

Cl(CNCMe₃)] (8)

72

25

[Pd{[EtꢀCꢁCꢀEt)₂(h⁵-C₅H₃)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH]-

Fe(h⁵-C₅H₅)}Cl] (9)

318 201

[Pd{[PhꢀCꢁCꢀPh)₂(h⁵-C₅H₃)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH]- 336 231

2.6. Conclusions

Fe(h⁵-C₅H₅)}Cl] (10)

[Pd{[MeO₂CCꢁCCO₂Me)₂(h⁵-C₅H₃)ꢀ

375

b

CHꢁNꢀCH₂ꢀCH₂ꢀOH]Fe(h⁵-C₅H₅)}Cl] (11)

The results presented in this study, show the great

versatility of the coordination mode of the ferrocenyl

Schiff base 1. In compounds 2 and 3 it binds to the

M(II) ion through the imine nitrogen exclusively, thus

acting as a neutral N-donor group, while in the cyclo-

palladated derivatives 4–8 the ferrocenyl imine behaves

as monoanionic (C,N)⁻bidentate ligand. The studies of

the reactivity of the ‘Pd(m-Cl)₂Pd’ moiety and of the

^aThe values given below refer to the ferroceneꢀferricinium couple.

^bNo reduction peak was observed in the reverse scan.

2.5. Electrochemistry

s(PdꢀC_{sp ,ferrocene}) bond allowed the isolation and char-

2

Electrochemical studies based on cyclic voltammetry

for compounds 1, 3–11 were undertaken. In all cases

the experiments were performed at ca. 20°C using 10⁻³

M solutions of the complexes in acetonitrile (HPLC

grade) and using different scan rates (from 0.1 to 100 V

acterization of monomeric complexes containing ﬁve-

(for 5–8) or nine-membered palladacycles (9–11). As

well as this, the s(PdꢀC_{sp ,ferrocene}) bond (in 4) exhibits

2

greater tendency to undergo the bis(insertion) of the

alkynes RꢀCꢂCꢀR than the s(PdꢀC_{sp ,aryl}) bond in

2

s

⁻¹).

[Pd{RꢀC₆H₃ꢀCHꢁNꢀC₆H₄-4-CH₃}(v-CH₃COO)]₂(I)

(with R=5-NO₂(Ib), 4-NO₂(Ic), 5-Cl (Id) or 4-Cl

(Ie)). However, attempts to insert tert-butylisonitrile

The cyclic voltammogram of the ligand showed one

anodic peak with a directly associated reduction peak

in the reverse scan, which is attributed to the one-elec-

tron oxidation–reduction process (Table 7). The posi-

tion of the peaks for 1 are consistent with the values

reported for related ferrocenyl Schiff bases of general

formula [(h⁵-C₅H₄)ꢀCHꢁNꢀR}Fe(h⁵-C₅H₅)] [23].

The cyclic voltammogram of 3 was similar to that of

the free ligand except for the position of the wave

which appeared strongly shifted to more anodic poten-

tials (E_1/2=267 mV). This is consistent with the results

reported for [(h⁵-C₅H₅)Fe{(h⁵-C₅H₄)ꢀCHꢁNꢀNMe₂}]

(E_1/2= −30 mV) and trans-[Pd{(h⁵-C₅H₅)Fe{(h⁵-

C₅H₄)ꢀCHꢁNꢀNMe₂}Cl₂] [39] (E_1/2=320 mV), thus

suggesting that the coordination of the palladium to the

N-donor ligands inhibits the oxidation of the ferrocenyl

unit. Except for compound 11, the cyclic voltam-

mograms of the remaining palladium(II) compounds

also showed one anodic peak with a directly associated

reduction peak in the reverse scan. The tendency of

the ferrocenyl unit to oxidize in the palladium(II)

into the s(PdꢀC_{sp ,ferrocene}) bond of 4 were unsuccess-

2

ful in all the studied cases. This observation differs

from the results obtained for [Pd{5%-OCH₃ꢀC₆H₃ꢀ

CHꢁNꢀC₆H₄-4-CH₃}(m-Cl)]₂(Ia), which contains a

s(PdꢀC_{sp ,aryl}) bond, which reacted with the same isoni-

2

trile under identical experimental conditions.

3. Experimental

3.1. General comments

Ferrocenecarboxaldehyde, 2-ethanolamine, triphenyl-

phosphine, deuterated pyridine, 1,2-bis(diphenylphos-

phino)ethane and the alkynes: hex-3-yne, diphenyl-

acetylene and dimethylacetylenedicarboxylate were ob-

tained from standard sources and used as received.

cis-[PtCl₂(dmso)₂] was prepared as described before

[53]. Some of the preparations described below require

benzene, which should be handled with CAUTION.

Elemental analyses (C, H, N and S (for 3)) were

carried out at the Serveis Cient´ıﬁco-Te`cnics (U.B.).

complexes containing ﬁve-membered rings and

s(PdꢀC_{sp ,ferrocene}) bond depends on the nature of the

remaining ligands bound to the palladium, as reﬂected

a

2

in the increase of the E_pavalues which follow the

C. Lo´pez et al. / Journal of Organometallic Chemistry 598 (2000) 87–102

99

Infrared spectra were obtained with a Nicolet Impact-

400 FTIR instrument using KBr pellets. Routine H-

terization data: Anal. Calc. for C₁₅H₂₁NO₂Cl₂FePtS: C,

29.97; H, 3.52, N, 2.33 and S, 5.20. Found: C, 29.6; H,

1

3.5; N, 2.40; S, 5.3. IR: w(\CꢁNꢀ): 1629 cm⁻¹

.

¹⁹⁵Pt-

NMR spectra were recorded at ca. 20°C on a Gemini

200 MHz instrument using CDCl₃(99.5%) as solvent

and SiMe₄as internal standard. ¹³C{¹H}-NMR spectra

were preformed ca. 20°C with a Varian 300 NMR

instrument using CDCl₃as solvent and SiMe₄as inter-

nal standard. The spectra ¹H–¹³C two-dimensional

NMR were run at 500 MHz either using a Varian

VXR-500 or a Bruker Avance DMX 500 instrument.

Heteronuclear single-quantum coherence ¹H–¹³C

(HSQC) with gradient selection and phase-sensitive ex-

periments were recorded. A total of 2×128 increments

of 2 K spectra (two scans) were collected and zero-ﬁlled

to 512 in F₁and 4096 in F₂.

NMR (in ppm): −3025.

3.2.3. trans-[Pd{[(p⁵-C₅H₄)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH]-

Fe(p⁵-C₅H₅)}₂Cl₂] (3)

A 200 mg (7.78×10⁻⁴mol) amount of ligand 1 was

dissolved in 5 cm³of methanol. Then a solution con-

taining 114 mg (7.78×10⁻⁴mol) of Na₂[PdCl₄] and 5

cm³of methanol was added. The resulting mixture was

stirred at room temperature (ca. 20°C) for 1 h. The

orange–red solid formed during this period was col-

lected by ﬁltration, washed with methanol (ca. 3 cm³)

and air-dried. (Yield: 79%). Characterization data:

Anal. Calc. for C₂₆H₃₀N₂O₂Cl₂Fe₂Pd·H₂O: C, 44.01; H,

4.55; N, 3.95. Found: C, 43.8; H, 4.45; N, 3.9%. IR:

³¹P{¹H}-NMR spectra of compounds 6 and 7 were

recorded at ca. 20°C with a Bruker 250 DXR instru-

ment using CDCl₃as solvent and P(OMe)₃as standard,

(l ³¹P [P(OMe)₃]ꢁ140.17 ppm). ¹⁹⁵Pt{¹H}-NMR spec-

trum of 2 was recorded with a Bruker 250 DXR

instrument using CDCl₃as solvent.

w(\CꢁNꢀ): 1586 cm⁻¹

.

3.2.4. [Pd{[(p⁵-C₅H₃)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH]-

Fe(p⁵-C₅H₅)}(v-Cl)]₂(4)

A mixture containing the ferrocenylimine 1 (300

mg, 1.17×10⁻³mol), Na₂[PdCl₄] (0.344 g, 1.17 mmol),

Na(CH₃COO)^.3H₂O (0.159 g, 1.17×10⁻³mol) and

30 cm³of methanol was stirred at room temperature for

12 h. The solid formed was collected by ﬁltration,

washed with methanol (3×5 cm³) and air-dried. (Yield:

59%). Compound 4 was recrystallized in CH₂Cl₂. Char-

acterization data: Anal. Calc. for C₂₆H₂₈N₂O₂Fe₂-

Pd₂Cl^.₂CH₂Cl₂: C, 36.82; H, 3.43; N, 3.19. Found:

3.2. Preparation of the compounds

3.2.1. [{(p⁵-C₅H₄)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH}]Fe-

(p⁵-C₅H₅)] (1)

Ferrocenecarboxaldehyde (1.090 g, 5.1×10⁻³mol)

was suspended in 20 cm³of benzene and stirred at

room temperature for 10 min. The undissolved materi-

als were ﬁltered out and discarded. Then, 0.311 g

(5.1×10⁻³mol) of 2-aminoethanol was added to the

ﬁltrate. The reaction ﬂask was connected to a con-

denser equipped with a Dean–Stark apparatus. The

mixture was reﬂuxed in an ethyleneglycol bath until

ca. 10 cm³had condensed in the Dean–Stark appara-

tus. Then, the hot solution was carefully ﬁltered out,

and the ﬁltrate was allowed to cool to room tempera-

ture. During this period, bright-orange needles formed.

The crystals were collected by ﬁltration and air-dried.

(Yield: 82%). Characterization data: Anal. Calc.

for C₁₃H₁₅NOFe: C, 60.73; H, 5.88 and N, 5.45. Found:

C, 60.5; H, 5.8; N, 5.6%. IR: w(\CꢁNꢀ): 1649

C, 36.9; H, 3.3; N, 3.2%. IR: w(\CꢁNꢀ): 1586 cm⁻¹

.

3.2.5. [Pd{[(p⁵-C₅H₃)CHꢁNꢀCH₂ꢀCH₂ꢀOH]-

Fe(p⁵-C₅H₅)}Cl(py-d₅)] (5)

This complex was prepared in situ and characterized

by NMR spectroscopies. The method used for its syn-

thesis was as follows: compound 4 (50 mg, 5.68×10⁻⁵

mol) was suspended in 0.7 cm³of CHCl₃, then an

excess of deuterated pyridine (py-d₅) (10 ml, 1.2×10⁻⁴

mol) was added. The reaction mixture was shaken

vigorously at room temperature (ca. 20°C) for 2 min to

favor the dissolution of the di-m-chloro cyclopalladated

complex, and produced an orange solution.

cm⁻¹

.

3.2.2. trans-[Pt{[(p⁵-C₅H₄)ꢁNꢀCH₂ꢀCH₂ꢀOH]-

Fe(p⁵-C₅H₅)}Cl₂(dmso)] (2)

A

3.2.6. [Pd{[(p⁵-C₅H₃)CHꢁNꢀCH₂ꢀCH₂ꢀOH]-

Fe(p⁵-C₅H₅)}Cl(PPh₃)] (6)

100 mg amount (2.37×10⁻⁴mol) of cis-

Triphenylphosphine (115 mg, 4.4×10⁻⁴mol) was

added to a suspension containing 150 mg (2.2×10⁻⁴

mol) of 4 and 10 cm³of benzene. Then the reaction

mixture was stirred at room temperature (ca. 20°C) for

1 h. The undissolved materials were removed by ﬁltra-

tion and discarded. The ﬁltrate was then concentrated

to dryness on a rotary evaporator giving an orange–red

residue, which was treated with the minimum amount

of CH₂Cl₂. Addition of n-hexane produced the precipi-

[PtCl₂(dmso)₂] was suspended in 20 cm³of methanol

and reﬂuxed until complete dissolved. Then a solution

formed from 61 mg (2.37×10⁻⁴mol) of 1 and 5 cm³

of methanol was added, and the reaction mixture was

stirred at room temperature for 5 h. The undissolved

materials were removed by ﬁltration and discarded. The

red ﬁltrate was then concentrated to ca. 10 cm³on a

rotary evaporator. The deep-red solid formed was col-

lected by ﬁltration and air-dried (Yield: 45%). Charac-

100

C. Lo´pez et al. / Journal of Organometallic Chemistry 598 (2000) 87–102

tation of a reddish solid which was collected by ﬁltra-

tion and air-dried. (Yield: 75%). Characterization data:

Anal. Calc. for C₃₁H₂₉NOFePPdCl: C, 56.3; H, 4.43;

N, 2.12. Found: C, 56.25; H, 4.45; N, 2.0%. IR:

H, 6.10; N, 2.49. Found: C, 53.7; H, 6.2; N, 2.3%. IR:

w(\CꢁNꢀ): 1628 cm⁻¹. For 10: Anal. Calc. for

C₄₁H₃₄ClNOFePd·CH₂Cl₂: C, 60.10; H, 4.32; N, 1.67.

Found: C, 60.05; H, 4.4; N, 1.7%. IR: w(\CꢁNꢀ): 1632

cm⁻¹. For 11: Anal. Calc. for C₂₅H₂₆ClNO₉FePd: C,

44.02; H, 3.84; N, 2.05. Found: C, 43.95; H, 3.85; N,

w(\CꢁNꢀ): 1602 cm⁻^{1 31}P-NMR (in ppm): 37.40.

.

3.2.7. [Pd{[(p⁵-C₅H₃)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH]-

1.9%. IR: w(\CꢁNꢀ): 1640 cm⁻¹

.

Fe(p⁵-C₅H₅)}(dppe)]Cl (7)

A 200 mg (2.9×10⁻⁴mol) amount of 4 was sus-

pended in 20 cm³of CH₂Cl₂. Then, a stoichiometric

amount of dppe (225 mg, 5.8×10⁻⁴mol) was added.

The resulting mixture was stirred at room temperature

(ca. 20°C) for 20 min and ﬁltered out. The orange–red

ﬁltrate was concentrated to ca. 5 cm³on a rotary

evaporator. Evaporation of the solvent at room temper-

ature produced a microcrystalline red solid, which was

collected by ﬁltration and air-dried. (Yield: 71%). Char-

acterization data: Anal. Calc. for C₃₈H₃₈ClNOFeP₂-

Pd·1/2CH₂Cl₂: C, 55.93; H, 4.75; N, 1.67. Found: C,

3.3. Electrochemistry

Cyclic voltammograms were obtained on

a

VERSSTAT potentiostat under argon at 25°C using

acetonitrile as solvent and [Bu₄N][PF₆] (0.1 mol×

dm⁻³) as supporting electrolyte. The potentials were

referred to an AgꢀAgNO₃(0.1 mol×dm⁻³) electrode

separated from the solution by a medium-porosity frit-

ted disc. A platinum wire auxiliary electrode was used

in conjunction with a platinum disc working electrode

and a Tacussel EDI-rotary electrode (3.14 mm²). A

cyclic voltammogram of freshly prepared (10⁻²mol

dm⁻³) solution of the complexes in CH₃CN was

recorded at 10 V s⁻¹, and the values of the measured

potentials were afterwards referred to the fer-

roceneꢀferrocenium couple, which was used as internal

reference.

55.6; H, 4.8; N, 1.7%. IR: w(\CꢁNꢀ): 1605 cm⁻¹

.

³¹P-NMR (in ppm): 48.04 and 62.38.

3.2.8. [Pd{[(p⁵-C₅H₃)ꢁNꢀCH₂ꢀCH₂ꢀOH]-

Fe(p⁵-C₅H₅)}Cl(CNCMe₃)] (8)

A 200 mg (2.9×10⁻⁴mol) amount of 4 was sus-

pended in 20 cm³of CH₂Cl₂. Then, the stoichiometric

tert-butylisonitrile (70 ml, 6.1×10⁻⁴mol) was added.

The resulting mixture was stirred at room temperature

(ca. 20°C) for 2 h and ﬁltered out. The red ﬁltrate was

concentrated to ca. 5 cm³on a rotary evaporator.

Evaporation of the solvent at room temperature pro-

duced small red–violet crystals, which were collected by

ﬁltration and air-dried. (Yield: 65%). Characterization

data: Anal. Calc. for C₁₈H₂₃ClN₂OFePd: C, 44.94; H,

4.82; N, 5.82. Found: C, 45.0; H, 4.9; N, 5.75%. IR:

3.4. Crystal structure analyses of 1, 6, 8 and 10

A prismatic crystal (0.1×0.1×0.2 mm) of 1, 6, 8 or

10 was selected and mounted on an Enraf–Nonius

CAD4 four circle diffractometer. Unit cell parameters

(Table 8) were determined from automatic centering of

25 reﬂections in the range 12BqB21° and reﬁned by

the least-squares method in all cases. Intensities were

collected with a graphite monochromated MoꢀK_aradi-

ation, using a ꢀ/2q scan technique. A total of 1913

reﬂections (for 1), 6349 reﬂections (for 6), 4625 reﬂec-

tions (for 8) and 4389 (for 10) were measured in the

ranges: 2.44BqB29.5°, 2.20BqB29.97°, 2.44BqB

29.97° and 2.20BqB31.51° for 1, 6, 8 and 10, respec-

tively. The number of non-equivalent reﬂections by

symmetry was 1913 for 1 [R_int(on I)=0.053], 6290 for

6 [R_int(on I)=0.017], 4446 for 8 [R_int(on I)=0.042]

and 4389 for 10 [R_int(on I)=0.014]. The number of

observed reﬂections [I\2|(I)] is given in Table 8.

Three reﬂections were measured every 2 h as orienta-

tion and intensity control and no signiﬁcant decay was

observed. Lorentz polarization corrections were per-

formed, but absorption corrections were not.

w(\CꢁNꢀ): 1605 cm⁻¹

.

3.2.9. [Pd{[(RꢀCꢁCꢀR)₂(p⁵-C₅H₃)ꢀCHꢁNꢀCH₂ꢀ

CH₂ꢀOH]Fe(p⁵-C₅H₅)}Cl] (R =Et (9), Ph (10) or

CO₂Me (11))

Complex 4 (206 mg, 3.0×10⁻⁴mol) was suspended

in 20 cm³of CHCl₃, then 1.2×10⁻³mol of the corre-

sponding alkyne was added dropwise for ca. 10 min.

Once the addition had ﬁnished, the reaction mixture

was reﬂuxed for 1.5 h. The resulting red–brown solu-

tion was ﬁltered out and the ﬁltrate was concentrated to

ca. 5 cm³on a rotary evaporator. The residue was then

passed through a SiO₂column (10 mm×250 mm).

Elution with a 100:1 CHCl₃–CH₃OH mixture released

an orange band, which was concentrated to dryness on

a rotary evaporator giving an orange solid, which was

collected and vacuum dried. (Yields: 67, 62 and 56% for

9, 10 and 11, respectively). Good crystals for X-ray

analyses of 10 were obtained by slow evaporation of a

CH₂Cl₂solution at room temperature. Characterization

data for 9: Anal. Calc. for C₂₅H₃₄ClNOFePd: C, 53.41;

The structures were solved by direct methods using

the SHELXS computer program [54] and reﬁned by

full-matrix least-squares methods with the SHELX-93

computer program [55] using 1846 reﬂections (for 1),

6420 (for 6), 4396 (for 8) and 5952 (for 10) (very

negative intensities were not assumed). The functions

minimized were: S wꢁF_oꢀ −ꢀF_cꢀ ꢀ , where w=[|²(I)+

2

2 2

C. Lo´pez et al. / Journal of Organometallic Chemistry 598 (2000) 87–102

101

Table 8

Crystal data and details of the reﬁnement of the crystal structure of compounds: [(h⁵-C₅H₅)Fe{(h⁵-C₅H₄)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH}] (1),

[Pd{[(h⁵-C₅H₃)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH]Fe(h⁵-C₅H₅)}Cl(PPh₃)] (6), [Pd{[(h⁵-C₅H₃)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH]Fe(h⁵-C₅H₅)}Cl(CNCMe₃)] (8) and

[Pd{[(PhꢀCꢁCꢀPh)₂(h⁵-C₅H₃)ꢀCHꢁNꢀCH₂ꢀCH₂ꢀOH]Fe(h⁵-C₅H₅)}Cl] (10)

1

6

8

10

Empirical formula

Formula weight

T (K)

C₁₃H₁₅FeNO

257.11

293(3)

C₃₁H₂₉ClFeNOPdP

660.22

293(2)

C₁₈H₂₃ClFeN₂OPd

481.08

293(2)

C₄₂H₃₆Cl₃FeNOPd

839.32

293(2)

,

u (MoꢀK_a) (A)

0.71069

Monoclinic

P2₁/a

7.779(6)

10.159(5)

14.816(4)

90.0

100.54(5)

90.0

1151.1(11)

1.484

0.71069

Triclinic

0.71069

Monoclinic

P2₁/c

7.575(10)

16.689(13)

15.040(4)

90.0

95.84(6)

90.0

1892(3)

1.689

0.71069

Triclinic

Crystal system

(

Space group

P1

,

a (A)

9.838(9)

11.016(5)

13.660(3)

96.60(3)

96.06(4)

108.02(5)

1382.8(14)

1.586

10.165(7)

12.304(6)

14.960(10)

83.56(5)

78.51(5)

67.65(4)

1694(2)

1.645

,

b (A)

,

c (A)

h (°)

i (°)

k (°)

3

,

V (A )

D_calc.(mg m⁻³

)

v (mm⁻¹

F(000)

)

1.286

536

1.354

668

1.865

968

1.232

852

q Range (°)

Index ranges

2.44, 29.95

−105h510,

05k514,

05l520

1913

2.20, 29.97

−135h513,

−155k515,

05l519

6349

2.44, 29.97

−105h510, 05k5

23, 05l521

2.20, 31.51

−145h514,

−165k517,

05l520

6019

No. of reﬂections collected

No. of independent reﬂections

[R_int(on F)]

Reﬁnement method

No. of data

4625

4446

0.0429

1846

0.0539

6290

0.0172

5952

0.0144

Full-matrix least-squares on F²

1846

6420

4396

5952

No. of parameters

Goodness of ﬁt on F²

Final R [I\2|(I)]

202

0.814

450

1.035

199

1.037

503

0.786

R₁=0.0397,

wR₂=0.0666

R₁=0.0763,

wR₂=0.0733

0.413 and −0.438

R₁=0.0485,

wR₂=0.0998

R₁=0.0586,

wR₂=0.1088

0.429 and −0.471

R₁=0.0583,

wR₂=0.1431

R₁=0.0673,

wR₂=0.1626

0.460 and −0.170

R₁=0.0389,

wR₂=0.0631

R₁=0.0692,

wR₂=0.0687

0.700 and −0.611

R indices (all data)

Largest difference peak and

−3

,

hole (e A

)

2

(0.00186P)²]⁻¹for 1; w=[|²(I)+(0.0513P)²]⁻¹for 6,

w=[|²(I)+(0.1021P)²]⁻¹for 8, and w=[|²(I)+

ꢀFꢀ )=0.066 (for 1), 0.099 (for 6), 0.143 (for 8) and 0.063

(for 10). Further details concerning the reﬁnement of the

structures of compounds 1, 6, 8 and 10 are summarized

in Table 8.

(0.0105P)²]⁻¹for 10, and P=[ꢀF_oꢀ +2ꢀF_cꢀ ]/3. ƒ, ƒ% and

ƒ%% were taken from the literature [56]. For 1, 14 hydrogen

atoms were located from a difference synthesis and

reﬁned with an overall isotropic temperature factor and

one hydrogen was computed and reﬁned with an overall

isotropic temperature factor using a riding model. For

compounds 6 and 8, all hydrogen atoms were located

from a difference synthesis and reﬁned with an overall

isotropic temperature factor. For 10, 15 hydrogen atoms

were located from a difference syntheses and were reﬁned

with an overall isotropic temperature factor, and 21

hydrogen atoms were computed and reﬁned with an

overall isotropic temperature factor using a riding model.

The ﬁnal R (on F) factors were 0.039, 0.048, 0.058 and

0.038 for 1, 6, 8 and 10, respectively, and wR (on

2

4. Supplementary material

Further details of the crystal structures (CIF ﬁles) of

compounds 1, 6, 8 and 10 are available from the

Cambridge Crystallographic Data Centre. CCDC nos.:

127947 (for 1), 127948 (for 6), 127949 (for 8) and 127950

(for 10). Copies of this information may be obtained free

of charge from: The Director, CCDC, 12 Union Road,

Cambridge, CB2 1EZ, UK (fax: +44-1223-336033;

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

ccdc.cam.ac.uk).

102

C. Lo´pez et al. / Journal of Organometallic Chemistry 598 (2000) 87–102

[25] R. Bosque, C. Lo´pez, J. Sales, X. Solans, M. Font-Bard´ıa, J.

Acknowledgements

Chem. Soc. Dalton Trans. (1994) 735.

[26] R. Bosque, M. Font-Bard´ıa, C. Lo´pez, J. Sales, J. Silver, X. Solans,

J. Chem. Soc. Dalton Trans. (1994) 747.

[27] C. Lo´pez, R. Bosque, X. Solans, M Font-Bardia, New. J. Chem.

20 (1996) 1285.

[28] T.H. Allen, O. Kennard, Chem. Des. Automat. News 8 (1993) 146.

[29] Y.J. Wu, L. Ding, H.X. Wang, Y.H. Liu, H.Z. Yuan, X.A. Mao,

J. Organomet. Chem. 535 (1997) 49.

[30] R. Bosque, C. Lo´pez, X. Solans, M. Font-Bard´ıa, Organometallics

18 (1999) 1267 and references therein.

We thank the Ministerio de Educacio´n and the Gen-

eralitat de Catalunya for ﬁnancial support (Grants:

PB96-0164 and 1997-SRG-0044). We are also grateful

to Dr C. Muller (Departament de Qu´ımica-F´ısica,

U.B.) for the facilities provided for the electrochemical

studies.

[31] R. Bosque, C. Lo´pez, J. Sales, X. Solans, J. Organomet. Chem.

483 (1994) 61.

[32] M. Pfeffer, Recl. Trav. Chim. Pays-Bas 109 (1990) 567.

[33] A.D. Ryabov, Synthesis (1985) 233.

[34] A. Albinati, P.S. Pregosin, R. Ru¨edi, Helv. Chim. Acta 68 (1985)

2046.

[35] C. Hansch, A. Leo, D. Hoekman, Exploring QSAR: Hydropho-

bic, Electronic and Steric Constants, ACS, Washington, DC, 1995.

[36] A.D. Ryabov, R. van Eldik, G. Le Borgne, M. Pfeffer,

Organometallics 12 (1993) 1386.

References

[1] A. Togni, Ferrocenes. Homogeneous Catalysis. Organic Synthesis.

Materials Sciences, VCH, Weinheim, 1995.

[2] W.R. Cullen, J.D. Woolins, Coord. Chem. Rev. 39 (1981) 1.

[3] I.R. Whittall, A.M. McDonagh, M.G. Humphrey, M. Samoc, in:

F.G.A. Stone, R. West (Eds.), Advances in Organometallic

Chemistry, vol. 42, Academic Press, San Diego, CA, 1998, p. 291.

[4] O. Crespo, M.C. Gimeno, P.G. Jones, A. Laguna, C. Sarroca,

Chem. Commun. (1998) 1481.

[5] J.M. Poblet, M. Be´nard, Chem. Commun. (1998) 1179.

[6] K. Severin, R. Bergs, W. Beck, Angew. Chem. Int. Ed. Engl. 37

(1998) 1634.

[37] ^SPARTAN5.0, Wavefunction Inc., 1995, 18401-Von Karman, Av.

370-Irvine, CA-92612, USA.

[38] G. Natile, F. Gasparrini, D. Misiti, G. Perego, J. Chem. Soc.

Dalton Trans. 1977, 1747.

[39] C. Lo´pez, R. Bosque, X. Solans, M. Font-Bard´ıa, J. Organomet.

Chem. 535 (1997) 99.

[7] Y. Nishibayashi, I. Takei, S. Uemura, M. Hidai, Organometallics

17 (1998) 3420.

[40] C. Lo´pez, J. Granell, J. Organomet. Chem. 555 (1998) 211.

[41] M. Benito, C. Lo´pez, X. Solans, M. Font-Bard´ıa, Tetrahedron:

Asymm. 9 (1998) 4219.

[42] C. Lo´pez, R. Bosque, D. Sainz, X. Solans, M. Font-Bard´ıa,

Organometallics 16 (1997) 3261.

[8] L. Schwink, P. Knochel, T. Eberle, J. Okuda, Organometallics 17

(1998) 7.

[9] S. Back, H. Pritzkow, H. Lang, Organometallics 17 (1998) 41.

[10] W.C. du Plessis, T.G. Vosloo, J.C. Swarts, J. Chem. Soc. Dalton

Trans. (1998) 2507.

[43] P.S. Pregosin, Coord. Chem. Rev. 44 (1982) 247.

[44] P.R.R. Ranatunge-Bandarage, N.W. Duffy, S.M. Johnston, B.H.

Robinson, J. Simpson, Organometallics 13 (1994) 511.

[45] X. Riera, V. Moreno, M. Font-Bard´ıa, X. Solans, Polyhedron 18

(1998) 65.

[11] M.A. Zhuravel, D.S. Glueck, L.M. Liable-Sands, A.L. Rheingold,

Organometallics 17 (1998) 574.

[12] C. Jiang, Y.S. Wen, L.K. Liu, T.S.A. Hor, Y.K. Yan,

Organometallics 17 (1998) 173.

[13] A.D. Ryabov, G.M. Kazankov, I.M. Payashkina, O.V. Gro-

zovsky, O.G. Dyachenko, V.A. Polyakov, L.G. Kuz’mina, J.

Chem. Soc. Dalton Trans. (1997) 4385.

[46] A. Caubet, C. Lo´pez, R. Bosque, J. Organomet. Chem. 577 (1999)

292.

[47] W. Tao, L.J. Silverberg, A.L. Rheingold, R.F. Heck,

Organometallics 8 (1989) 2550.

[14] C. Lo´pez, R. Bosque, X. Solans, M. Font-Bard´ıa, New J. Chem.

22 (1998) 977.

[48] J.P. Sutter, M. Pfeffer, A. De Cian, J. Fischer, Organometallics

11 (1992) 386.

[49] M. Pfeffer, M.A. Rotteveel, J.P. Sutter, A. De Cian, J. Fischer,

J. Organomet. Chem. 371 (1989) C21.

[15] C.E.L. Headford, R. Mason, P.R. Ranantunge-Bandarage, B.H.

Robinson, J. Simpson, J. Chem. Soc. Chem. Commun. (1990) 601.

[16] R. Costa, C. Lo´pez, E. Molins, E. Espinosa, Inorg. Chem. 37

(1998) 5686.

[50] M. Pfeffer, J.P. Sutter, A. De Cian, J. Fischer, Inorg. Chim. Acta

220 (1994) 115.

[51] C. Lo´pez, X. Solans, D. Tramuns, J. Organomet. Chem. 471 (1994)

265.

[52] C. Lo´pez, R. Bosque, X. Solans, M. Font-Bard´ıa, J. Silver, G.

Fern, J. Chem. Soc. Dalton Trans. (1995) 1839.

[53] J.H. Price, A.N. Williamson, R.F. Schramm, B.B. Wayland,

Inorg. Chem. 11 (1972) 1280.

[17] A. Benito, J. Cano, R. Martinez-Ma´n˜ez, J. Soto, J. Paya´, F. Lloret,

M. Julve, J. Faus, M.D. Marcos, Inorg. Chem. 32 (1993) 1197.

[18] M. Bracci, C. Ercolani, B. Floris, M. Bassetti, A. Chiesi-Villa, C.

Guastini, J. Chem. Soc. Dalton. Trans. (1990) 1357.

[19] A. Louati, M. Gross, L. Douce, D. Matt, J. Organomet. Chem.

438 (1992) 167.

[20] K. Hamamura, M. Kita, M. Nonoyama, J. Fujita, J. Organomet.

Chem. 463 (1993) 169.

[54] G.M. Sheldrick, Acta Crystallogr. Sect. A 46 (1990) 467.

[55] G.M. Sheldrick, ^SHELXL-93, A Computer Program for Determina-

tion of Crystal Structures, University of Go¨ttingen, Germany,

1994.

[56] International Tables of X-Ray Crystallography, vol. IV, Kynoch

Press, Birmingham, UK, 1974, pp. 99, 100 and 149.

[21] C. Lo´pez, R. Bosque, X. Solans, M. Font-Bard´ıa, J. Silver, G.

Fern, J. Chem. Soc. Dalton Trans. (1995) 1839.

[22] J.C. Kotz, E.E. Getty, L. Lin, Organometallics 4 (1985) 610.

[23] R. Bosque, C. Lo´pez, J. Sales, Inorg. Chim. Acta 244 (1996) 141.

[24] C. Lo´pez, J. Sales, X. Solans, R. Zquiak, J. Chem. Soc. Dalton

Trans. (1992) 2321.

.

Article Doi

Platinum(II) and palladium(II) compounds derived from [(η5-C5H5)Fe{(η5-C 5H4)-CH=N-CH2-CH2-OH}]

DOI: 10.1016/S0022-328X(99)00682-8

Source and publish data:

Authors:

Article abstract of DOI:10.1016/S0022-328X(99)00682-8

Full text of DOI:10.1016/S0022-328X(99)00682-8

Products guided by the article

R&D Labs maybe for 267661-67-6

Relevant to this article

Hot Product