Synthesis, characterization of [{(N-methyl-N-benzyl)amino}methyl]ferrocenes and their cyclopalladated complexes: Crystal structure of σ-Pd[(η5-C5H5)Fe(η5-C5H3CH2N(CH3)

Article abstract of DOI:10.1016/j.ica.2006.05.019

Condensation of aminomethylferrocene (1) and substituted benzaldehydes resulted in aldimines 2a-c which followed by reduction with sodium borohydride to give 3a-c. N-methylation of 3a-c with HCHO/NaCNBH₃/HOAc led to 4a-c. Treatment of 4a-c with

Full text of DOI:10.1016/j.ica.2006.05.019

Inorganica Chimica Acta 359 (2006) 4114–4120
www.elsevier.com/locate/ica
Synthesis, characterization of [{(N-methyl-N-benzyl)amino}methyl]-
ferrocenes and their cyclopalladated complexes: Crystal structure of
r-Pd[(g5-C5H5)Fe(g5-C5H3CH2N(CH3)CH2C6H4NO2-4)]Cl(PPh3)
a,
a
a
a
Hong-Xing Wang *, Hong-Fei Wu , Hui-Chao Zhou , Feng-Ying Geng ,
a
a
a
a
b
Ren-Qing Gao , Xiao-Li Yang , Li Wan , Wen-Qin Zhang , Rong Jin
a
Department of Chemistry, College of Sciences, Tianjin University, No. 92, Weijin Road, Nankai District, Tianjin 300072, PR China
b
Department of Ultrasound, The First Central Hospital of Tianjin, Tianjin 300192, PR China
Received 13 April 2006; received in revised form 12 May 2006; accepted 12 May 2006
Available online 24 May 2006
Abstract
Condensation of aminomethylferrocene (1) and substituted benzaldehydes resulted in aldimines 2a–c which followed by reduction
with sodium borohydride to give 3a–c. N-methylation of 3a–c with HCHO/NaCNBH3/HOAc led to 4a–c. Treatment of 4a–c with
sodium palladium tetrachloride in the presence of sodium acetate afforded cleanly cyclopalladated 5a–c in which configurations consisted
of the RNRC, SNSC. The preferable activation of CFerrocenyl–H bond over CPhenyl–H bond was also observed. All compounds 2–5 were
1
characterized by elemental analysis, IR and H NMR. In addition, the molecular structure of 5c was confirmed by single crystal X-ray
diffraction. The possible mechanism for the formation of 5 was also discussed.
ꢀ 2006 Elsevier B.V. All rights reserved.
Keywords: Ferrocenylamines; N-methylation; Cyclopalladation; Stereoselectivity; Crystal
1. Introduction
of the endo effect. In addition, the preferred activations of
CFerrocenyl–H bond over CPhenyl–H bond were documented
very well in the literatures [6]. Although a large number
of cyclopalladated compounds have been described [6],
reports on cyclopalladated ferrocenylamines are still rare
[5,7] mostly because the lack of suitable substrates. In
the recent papers, we described the synthesis and character-
ization of [{(N-methyl-N-phenyl)amino}methyl]ferrocenes
(PFcN) and their cyclopalladated complexes in which
configurations consisted of RNRC, SNSC [8]. In addition,
such stereoselectivity was also observed in cycloplatinated
[{(N-methyl-N-benzyl)amino}methyl]ferrocenes [9]. In
order to extend our researches of stereoselective cyclomet-
allation on ferrocenylamines, in this paper, we wish to
report the cyclopalladation of [(N-methyl-N-benzyl)-
amino]methylferrocenes (Schemes 1 and 2) starting from
aminomethylferrocene and para-benzaldehydes, particu-
larly the relationship between the N–Pd coordination
modes and the selectivities.
Transition metals mediated activation of C(sp2)–H
bonds in the aromatic compounds especially those contain-
ing nitrogen-chelating atom has attracted much attention
[1] in the past decades due to their wide applications in
organic synthesis such as Heck reaction [2], Suzuki cou-
pling reaction [3], etc. The first example of cyclopalladation
of ferrocenylamines, i.e., N,N-dimethylaminomethylferro-
cene (FcN) was reported by Sokolov et al. [4]. Later, Lopez
and co-workers [5] found that treatment of ferrocenyli-
mines [(g5-C5H5)Fe(g5-C5H4CH2AN@CHC6H4R)] (R =
H, 2-Cl) with sodium palladium tetrachloride in the
presence of sodium acetate resulted in two kinds of cyclo-
palladated complexes either with a r-Pd–Csp2, Ferrocenyl
bond or with a r-Pd–Csp2, phenyl bond due to the presence
*
Corresponding author. Tel.: +86 22 27892355; fax: +86 22 27403475.
E-mail address: hongxing_wang@hotmail.com (H.-X. Wang).
0020-1693/$ - see front matter ꢀ 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2006.05.019

H.-X. Wang et al. / Inorganica Chimica Acta 359 (2006) 4114–4120
4115
12
12
12
14
17
14
17
14
17
11
5
11
5
11
5
13
18
13
18
13
18
15
16
15
16
15
16
NH2
i
1
1
1
2
2
2
N
N
N
H
R
R
R
19
ii
iii
Fe
Fe
Fe
Fe
6
7
6
6
7
7
10
10
10
1
2a-c
3a-c
4a-c
Scheme 1. (i) 4-RC6H4CHO(R = MeO (a), H (b), NO2 (c)), MeOH, reflux 2 h; (ii) NaBH4, methanol/water; (iii) NaCNBH3, HCHO (37%), CH3CO2H.
bond for the other ferrocenylimines [(g5-C5H5)Fe(g5-C5-
H4CH@NACH2C6H4R)] (ꢀm 1620 cmÀ1) [9] due to their
different systems of electron delocalization. In the 1H
NMR spectra of 2a–c, a singlet appeared at d 8.20 ppm
corresponds to H12. For 3a–c, the presence of a weak
absorption 3300 cmÀ1 in IR and a broad peak d
2.19 ppm (when D2O is added this peak disappeared) in
1H NMR both confirm the presence of a N–H group. In
4a–c, a singlet around d 2.14 ppm is assigned to H19 and
this value is very close to those (d 2.12 ppm) of the other
ferrocenylamines [(g5-C5H5)Fe(g5-C5H4CH2N(CH3)CH2-
C6H4R-4)](R@CH3, Cl) [9].
19
14
15
12
13
R
16
17
11
N
2
18
3
1
4
Pd Cl
PPh3
5 Fe
i
ii
4a-c
6
7
10
rac- 5a-c
Scheme 2. (i) Na2PdCl4, NaOAc, MeOH; (ii) PPh3, MeOH.
2. Results and discussion
For 5a–c, their IR spectra all display two medium
absorption bands around m 1100 and 1000 cmÀ1, implying
that an unsubstituted cyclopentadienyl ring (Cp) is present
[11]. In 1H NMR spectra, the d values of protons in N–CH3
shifts from upfield d ꢀ 2.14 ppm in 4 to downfield
d ꢀ 2.8 ppm in 5, suggesting that a N–Pd coordination
2.1. Synthesis of ferrocenylamines 4 and their
cyclopalladated compounds 6
Condensation of 1 and para-substituted benzaldehydes
produced ferrocenylimines 2a–c (Scheme 1) which were fol-
lowed by reduction with sodium borohydride to give quan-
titatively secondary 3a–c. N-methylation [10] of 3a–c with
aqueous formaldehyde, sodium cyanoborohydride and ace-
tic acid finally led to 4a–c in the moderate yields.
1
exists in 5. Also in H NMR spectra of 5, a broad doublet
and a multiplet around d ꢀ 3.70, 3.80 ppm are assigned to
H5 and H4, respectively, a doublet d ꢀ 3.90 ppm is attrib-
uted to H3. The protons on substituted phenyl rings all
give their corresponding splitting patterns.
Treatment of 4a–c with stoichiometric sodium palla-
dium tetrachloride in the presence of sodium acetate in
methanol resulted in cleanly cyclopalladated ferrocenylam-
ines 6a–c (Scheme 2). Compounds 6a–c were isolated as
red-brown solids in good yields after column chromatogra-
phy (see Section 3). They are very stable in air and soluble
in dichloromethane, chloroform, ethyl acetate, acetone and
benzene, but poorly soluble in methanol, particularly insol-
uble in petroleum ether.
Unlike PFcN which are easily oxidated by sodium palla-
dium tetrachloride [8], 4a–c show a strong anti-oxidation
ability toward palladium (II). It is believed that a stronger
coordination between 4a–c and Pd than the former and
hence reducing the oxidation potential of palladium (II)
accounts for such significant different behavior.
2.3. Chemoselectivity and stereoselectivity
It was observed that cyclopalladations of 4a–c exhibited
a preferable activation of CFerrocenyl–H bond over the CPhenyl
–
H bond. Since 4a–c have two different chemoselective met-
allation sites (Scheme 3), metallation of these two sites by
the coordinated N–Pd complexes 6 can provide stable five
membered rings 5 and 7, respectively. In fact, only 5a–c
were isolated in our experiment. The preferable activation
of CFerrocenyl–H bond in 4a–c is in good agreement with
our early observations [9], i.e., electrophilic substitution
of palladium on the ring with higher electron density (Cp
ring) is facile than that with lower electron density (phenyl
ring).
However, the 0 optical rotations of 5 measured at given
˚
2.2. Spectra characterizations of 2–5
conditions (k = 5893 A, CH2Cl2, 293 K) implies that they
probably consist of racemers and this hypothesis is out-
lined in Scheme 4. Theoretically, two isomers 4a,b are in
equilibrium and they will possess the similar conformation
Compounds 2–5 were characterized by elemental analy-
sis, IR and 1H NMR. Elemental analyses are in good
agreement with the proposed formula. In the IR spectra
of 2a–c, a strong absorption band appeared m 1640 cmÀ1
indicates that the C@N bond exists in these molecules.
And these data are in sharp contrast to those of the C@N
to
[(N-methyl-N-4-methylbenzyl)amino]methylferrocene
[13]. It can be imaged that after coordination the interme-
diates 6a(b) (Scheme 4) will keep the stable conformation
similar to that of coordinated Pt–FcN complex [12]. The

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H.-X. Wang et al. / Inorganica Chimica Acta 359 (2006) 4114–4120
N
N
Pd
PPh3
Cl
PPh3
R
R
Pd
Cl
Cl
5a-c
Fe
Fe
PPh3
L
6a-c
7a-c
Scheme 3. The preferred activation of C–H bond on Cp ring over that on phenyl ring. L = FcCH2N(CH3)CH2C6H4-R.
2
N
1
11
2
Fe 5
1
Bz
N
11
Fe5
Bz
4
Na2PdCl4
Na2PdCl4
Cl
2
L
Cl
Pd
1
11
N
2
1
Fe5
6
(RNSp)
trace
6
(SNRp)
trace
Bz
N
Cl
11
Fe5
Pd
Bz
Cl
L
6
PPh3
Cl
attack at C2
Ph3P
PPh3
attack at C5
2
Pd
1
11
N
2
Fe5
Bz
N
1
Pd
Bz
11
Fe5
Cl
(SNSp)
Ph3P
5
(RNRp)
5
Scheme 4. The possible mechanism for the formation of 5. L = FcCH2N(Me)CH2Ar.
palladium in 6a(b) either activate C2(5)–H bonds to give a
pair of enantiomers 5a(b) or rotate around C1–C11 bond
and then activate C5(2)–H bonds to produce another pair
of enantiomers 5c(d). Since the orientations of palladium
in 6a(b) approach C2–H, C5–H bonds, respectively [12],
thus activation of these bonds to yield 5a(b) will be
favored. And in turn, the formation of 5c(d) will not be dis-
favored due to the steric hindrance between benzyl and H
atom in Cp ring when N–Pt moiety rotates around the axis
of C1–C11 bond [9].
As we know, diastereomers can be easily separated by
chromatography, fractional crystallization, etc. We paid
much effort to isolate 5c(d) from 5a(b) by column chroma-
tography, only a trace product (assumed to be the pair of
5c(d)) was obtained and was not sufficient to identify.
Based on the discussion as mentioned above together with
the configuration (RNRC) of 5c (Fig. 1), we suggest that 5
consist of a pair 5a(b). In addition, the possible coordina-
tion of palladium with either isomer 4a or 4b resulting in
only a pair of diastereomers 5a,c or 5b,d is also excluded.
2.4. X-ray single crystal studies of 5c
The molecular structure of 5c was confirmed by single
crystal X-ray diffraction (Fig. 1). Crystallographic data,
selected bond lengths and angles are listed in Tables 1
and 2, respectively. X-ray diffraction studies demonstrate
that 5c consists of discrete molecules {PdCl(PPh3)[(g5-
C5H5)Fe(g5-C5H3CH2N(CH3)–CH2C6H4–NO2-4)]} sepa-
rated by van der Waals contact in which palladium is in
a slight distorted square-planar environment, bonded to
Cl1, P1, N1 and C29. The deviation of each atom from
the mean plane is Pd1, À0.0304; P1, 0.1353; N1, 0.1509;
˚
Cl1, À0.1079; C29, À0.1479 A, respectively. Compound
5c contains a bicycle, which is formed by the substituted
pentagonal ring of the ferrocenyl fragment and a five mem-
bered palladacycle with an envelop-like conformation. The
˚
bond length N1–Pd1 2.195 A is slightly longer than that in
˚
cyclopalladated FcN (2.170A) [6h]. In addition, trip-
henylphosphino moiety adopts a trans configuration to
N1, with a bond angle N1–Pd1–P1 169.00(9)ꢁ. The bond

H.-X. Wang et al. / Inorganica Chimica Acta 359 (2006) 4114–4120
4117
Table 2
Selected bond lengths (A) and angles (ꢁ) for compound 5c
˚
˚
Bond lengths (A)
Pd1–C29
Pd1–N1
Pd1–P1
Pd1–Cl1
1.988(4)
2.195(3)
2.224(1)
2.395(1)
N1–C26
N1–C27
N1–C19
C27–C28
1.484(5)
1.500(5)
1.501(5)
1.481(5)
Angles (ꢁ)
C29–Pd1–N1
C29–Pd1–P1
N1–Pd1–P1
C29–Pd1–Cl1
83.05(1)
91.20(1)
169.00(9)
171.99(1)
N1–Pd1–Cl1
P1–Pd1–Cl1
C27–N1–Pd1
C28–C29–Pd1
91.37(9)
95.22(4)
109.5(2)
113.0(3)
3. Experimental
3.1. Materials and instruments
Aminomethylferrocene was prepared according to the
literature procedure [14], substituted benzaldehydes, lith-
ium aluminum hydride, aqueous formaldehyde, sodium
cyanoborohydride, acetic acid, sodium acetate, triphenyl-
phosphine were obtained commercially and used without
further purification. Sodium palladium tetrachloride was
prepared in our laboratory. All of the solvents were purified
with standard methods prior to use. Melting points were
obtained from Yanaco micro melting point apparatus and
were uncorrected. Elemental analyses were measured from
Carlo Erba 1106 Elemental analyzer. 1H NMR spectra were
obtained with Bruker AV-400 spectrometer by using CDCl3
as a solvent and TMS as internal standard. IR spectra were
taken on BIO-RAD 3000 spectrophotometer.
Fig. 1. Crystal structure of 5c with numbering scheme (H atoms were
omitted for clarity).
Table 1
Crystallographic data for 5c
Compound
5c
Empirical formula
C
37H34ClFeN2O2PPd
Formula weight
767.33
Crystal dimensions (mm)
Crystal system, space group
0.28 · 0.16 · 0.10
monoclinic, P2(1)/c
17.451(2)
16.653(3)
11.704(2)
90.00
105.00(2)
90.00
3285.4(8)
4
˚
a (A)
3.2. Synthesis of ferrocenylaldimines 2
˚
b (A)
˚
c (A)
General procedure: To a stirred solution of aminometh-
ylferrocene (5 mmol) in 20 ml methanol was added drop-
wise a solution of substituted benzaldehyde (5.5 mmol) in
10 ml ethanol. The mixture was refluxed for 4 h and cooled
to room temperature. If no crystal precipitated, the mixture
was kept at 5 ꢁC in refrigerator or removed the solvent in
vacuo. The crude product was recrystallized from ethyl ace-
tate and petroleum ether (60–90 ꢁC) to give out 2a–c.
a (ꢁ)
b (ꢁ)
c (ꢁ)
3
˚
V (A )
Z
qcalcd (g cmÀ3
)
1.551
1.155
l (mmÀ1
)
h Range for data collection (ꢁ)
Limiting indices
1.72 6 h 6 26.45
À16 6 h 6 21,
À16 6 k 6 20,
À14 6 l 6 14
18330/6731
4026
3.2.1. {(g5-C5H5)Fe(g5-C5H4CH2N@CHC6H4OCH3-4)}
(2a)
Reflections collected/unique [Rint = 0.068]
Reflections [I > 2r(I)]
Yield: (55%); a red-brown solid; m.p. 67–70 ꢁC. Anal.
Calc. for C19H19FeNO: C, 68.49; H, 5.75; N, 4.20. Found:
C, 68.25; H, 5.73; N, 4.19%. FT-IR(KBr): 3092(w),
2935(w), 2888(w), 1641(m), 1604(s), 1512(s), 1315(s),
Data/restraints/parameters
Final R1, wR2 [I > 2r(I)]
Largest difference in peak and hole (e A
6731/0/407
0.042, 0.072
0.513 and À0.538
À3
˚
)
1258(s), 1167(s), 1104(m), 1028(s), 999(m), 816(s) cmÀ1
.
1H NMR (CDCl3): d 3.85(s, 3H, OCH3), 4.14(m, 2H, H2,
H5), 4.16(s, 5H, g5-C5H5), 4.21(m, 2H, H3, H4), 4.51(s,
2H, H11), 6.93(d, 2H, H15, H17), 7.71(d, 2H, H14, H18),
8.20(s, 1H, H12).
˚
length Pd1–CFerrocenyl 1.988(4) A is nearly the same as that
in cyclopalladated FcN (1.983(1) A) [6h]. The average C–C
bond length in the pentagonal rings 1.415 A is similar to
˚
˚
the values reported for the other ferrocene derivatives
[11]. The Fe–C (Cp ring) bond lengths range from 2.024
3.2.2. {(g5-C5H5)Fe(g5-C5H4CH2N@CHC6H5)} (2b)
Yield: (65%); a red-brown solid; m.p. 74–76 ꢁC [lit. [6g]:
72–76 ꢁC]. FT-IR(KBr): 3083(w), 2880(w), 1639(s),
˚
to 2.097 A. The two pentagonal rings of the ferrocenyl moi-
ety are planar and nearly parallel (the interplane angle
6.4ꢁ). In addition, the Cp rings are also nearly eclipsed.

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H.-X. Wang et al. / Inorganica Chimica Acta 359 (2006) 4114–4120
1577(m), 1447(m), 1302(s), 1215(m), 1101(s), 1002(s),
809(s), 692(s) cmÀ1
1105(m), 1001(w), 859(m), 831(m) cmÀ1. 1H NMR (CDCl3)
d 1.98(s, 1H, NH), 3.64(s, 2H, H11), 3.91(s, 2H, H12),
4.11(s, 5H, g5-C5H5), 4.16(d, 2H, H2, H5), 4.24(m, 2H,
H3, H4), 7.61(d, 2H, H14, H18), 8.20(d, 2H, H15, H17).
.
3.2.3. {(g5-C5H5)Fe(g5-C5H4CH2N@CHC6H4NO2-4)}
(2c)
Yield: (80%); a purple solid; m.p. 148–150 ꢁC. Anal.
Calc. for C18H16FeN2O2: C, 62.09; H, 4.63; N, 8.05.
Found: C, 61.93; H, 4.56; N, 8.01. FT-IR (KBr):
3105(w), 2837(w), 2363(w), 1643(m), 1603(m), 1524(s),
3.4. Synthesis of tertiary ferrocenylamines 4
General procedure: To a vigorous stirred solution of 3
(2 mmol) and 10 mmol of 37% aqueous formaldehyde in
20 ml of acetonitrile was added 0.20 g (3.2 mmol) of
sodium cyanoborohydride. Thirty minutes later, glacial
acid was added dropwise until the pH value of the mixture
reached neutral. The mixture was stirred at room tempera-
ture for 6 h and TLC monitored the reaction until it com-
pleted. The solvent was removed and 20 ml of 2N sodium
hydroxide was then added to the residue. The mixture
was stirred for 30 min. and extracted with diethyl ether
(3 · 20 ml), and finally separated. The organic layer was
dried over anhydrous sodium sulfate and removed to give
out crude product which was purified by column chroma-
tography (silica gel, ethyl acetate/petroleum ether (60–
90 Cꢁ) = 1:5, v/v) to afford 4a–c.
1343(s), 1103(m), 1001(m), 832(m) cmÀ1
.
1H NMR
(CDCl3): d 4.13(d, 2H, H2, H5), 4.16(s, 5H, g5-C5H5),
4.21(m, 2H, H3, H4), 4.59(2H, s, H11), 7.91(d, 2H, H14,
H18), 8.26(d, 2H, H15, H17), 8.33(s, 1H, H12).
3.3. Synthesis of secondary ferrocenylamines 3
General procedure: To a stirred solution of 2 (3.3 mmol)
in 20 ml dry THF was added sodium borohydride
(6.6 mmol) under the argon. The mixture was refluxed for
4 h and cooled to room temperature. Solvent was evapo-
rated under reduced pressure. The mixture was extracted
with dichloromethane (3 · 30 ml). The extract was dried
over anhydrous sodium sulfate and evaporated in vacuo.
The residue was recrystallized from ethyl acetate–petro-
leum ether (60–90 ꢁC) or crystallized from the above men-
tioned mixture of solvents or purified by column
chromatography (silica-gel, ethyl acetate–petroleum ether
(60–90 ꢁC) = 1:2, v/v) to give 3a–c.
3.4.1. {(g5-C5H5)Fe(g5-C5H4CH2N(CH3)CH2C6H4O-
CH3-4)} (4a)
Yield: (80%);
a yellow liquid. Anal. Calc. for
C20H23FeNO: C, 68.78; H, 6.64; N, 4.01. Found: C,
68.58; H, 6.60; N, 4.00%. FT-IR (KBr): 3094(w),
2935(w), 2835(m), 1612(s), 1512(s), 1463(m), 1365(w),
1301(m), 1246(s), 1175(s), 1105(s), 1035(s), 1003(s),
3.3.1. {(g5-C5H5)Fe(g5-C5H4CH2NHCH2C6H4OCH3-4)}
(3a)
.
815(s) cmÀ1 1H NMR((CDCl3): d 2.13(s, 3H, H19),
Yield: (83%);
a
yellow liquid. Anal. Calc. for
3.46(s, 3H, OCH3), 3.50(s, 2H, H11), 3.74(s, 2H, H12),
3.82(d, 2H, H2, H5), 4.09(s, 5H, g5-C5H5), 4.15(m, 2H,
H3, H4), 6.87(d, 2H, H15, H17)), 7.25(d, 2H, H14, H18).
C19H21FeNO: C, 68.08; H, 6.31; N, 4.18. Found: C,
67.83; H, 6.25; N, 4.12%. FT-IR (KBr): 3298(s), 3093(w),
2934(w), 2835(m), 2363(w), 1611(s), 1512(s), 1456(m),
1355(w), 1247(vs), 1175(s), 1105(m), 1035(s), 999(m),
3.4.2. {(g5-C5H5)Fe(g5-C5H4CH2N(CH3)CH2C6H5)}
(4b)
1
816(s) cmÀ1. H NMR(CDCl3): d 1.83(s, 1H, NH), 3.42(s,
3H, OCH3), 3.49(s, 2H, H11), 3.73(s, 2H, H12), 3.80(d,
2H, H2, H5), 4.09(s, 5H, g5-C5H5), 4.14(t, 2H, H3, H4),
6.86(d, 2H, H15, H17), 7.24(d, 2H, H14, H18).
Yield: (75%); a yellow solid; m.p. 39–40 ꢁC. Anal. Calc.
for C19H21FeN: C, 71.49; H, 6.63; N, 4.39. Found: C,
71.21; H, 6.58; N, 4.36%. FT-IR (KBr): 3093(w),
2938(w), 1598(w), 1491(m), 1448(s), 1326(m), 1105(s),
3.3.2. {(g5-C5H5)Fe(g5-C5H4CH2NHCH2C6H5)} (3b)
Yield: (70%); a yellow solid; m.p. 37–39 ꢁC. Anal. Calc.
for C18H19FeN: C, 70.84; H, 6.27; N, 4.59. Found: C,
70.59; H, 6.25; N, 4.55%. FT-IR (KBr): 3319(s), 3084(w),
2934(w), 2858(m), 1494(s), 1451(s), 1330(s), 1103(s),
1023(s), 999(m), 810(s), 733(s), 696(m) cmÀ1
.
1H
NMR(CDCl3): d 2.14(s, 3H, H19), 3.46(m, 4H, H11,
H12), 4.05(d, 2H, H2, H5), 4.10(s, 5H, g5-C5H5), 4.16(m,
2H, H3, H4), 7.27–7.32(m, 5H, H14-H18).
999(m), 803(s), 729(s), 697(s) cmÀ1
.
1H NMR(CDCl3) d
3.4.3. {(g5-C5H5)Fe(g5-C5H4CH2N(CH3)CH2C6H4NO2-
4)} (4c)
Yield: (85%); a yellow solid; m.p. 66–68 ꢁC. Anal. Calc.
for C19H20FeN2O2: C, 62.66; H, 5.53; N, 7.69. Found: C,
62.49; H, 5.48; N, 7.60%. FT-IR (KBr): 3081(w),
2935(w), 2836(w), 1600(w), 1517(s), 1465(w), 1345(s),
1.85(s, 1H, NH), 3.53(s, 2H, H11), 3.82(s, 2H, H12),
4.10(s, 5H, g5-C5H5), 4.11(d, 2H, H2, H5), 4.20(t, 2H,
H3, H4), 7.33(m, 5H, H14-H18).
3.3.3. {(g5-C5H5)Fe(g5-C5H4CH2NHCH2C6H4NO2-4)}
(3c)
Yield: (90%); a yellow solid; m.p. 97–98 ꢁC. Anal. Calc.
for C18H18FeN2O2: C, 61.74; H, 5.18; N, 8.00. Found: C,
61.68; H, 5.15; N, 7.98%. FT-IR (KBr): 3321(s), 3084(w),
2911(w), 1603(w), 1519(s), 1452(w), 1345(s), 1227(w),
1225(w),
1105(m),
1028(m),
1101(w),
857(m),
820(m) cmÀ1 1H NMR(CDCl3): d 2.15(s, 3H, H19),
.
3.46(s, 2H, H11), 3.51(s, 2H, H12), 4.10(s, 5H, g5-C5H5),
4.14(d, 2H, H2, H5), 4.16(m, 2H, H3, H4), 7.47–8.17(q,
4H, H14, H15, H17, H18).

H.-X. Wang et al. / Inorganica Chimica Acta 359 (2006) 4114–4120
4119
3.5. Synthesis of cyclopalladated ferrocenylamines 5
temperature over a period of one week. The single crystal
of this complex was mounted on a Bruker SMART CCD
diffractometer equipped with a monochromator graphited
General procedure: To a stirred solution of 4 (1 mmol),
sodium acetate (82 mg, 1 mmol) in 30 ml methanol was
added dropwise a solution of sodium palladium tetrachlo-
ride (0.29 g, 1 mmol) in 15 methanol. The mixture was stir-
red for 4 h at room temperature with protection of argon
gas and TLC monitored the reaction progress. Then triphe-
nylphosphine (0.41 g, 1.5 mmol) was added and the mix-
ture was stirred for another 30 min. The solvent was
removed in vacuo, the residue was purified by column chro-
matography (silica gel, ethyl acetate/petroleum ether (60–
90 Cꢁ) = 1:1, v/v) to give 5.
˚
Mo Ka (k = 0.71073 A) radiation at ambient temperature
(T = 294 K) using x À 2h multi-scans technique for data
collection. Semi-empirical absorption corrections were
applied using SABABS program [15]. The structure was
solved by direct methods and refined by full-matrix least-
squares procedure on F2 using the SHELX suite of program
[16]. Crystallographic data, selected bond lengths and
angles are listed in Tables 1 and 2, respectively.
4. Supplementary materials
3.5.1. [PdCl(PPh3){(g5-C5H5)Fe(g5-C5H3CH2N(CH3)-
CH2C6H4OCH -4)}] (5a)
Crystallographic data (excluding structure factors) for
the structure of 5c in this paper has been deposited with
the Cambridge Crystallographic Data Centre as supple-
mentary publication numbers CCDC-280750. Copies of
the data can be obtained, free of charge, on application
to CCDC, 12 Union Road, Cambridge CB2 1EZ, UK;
fax: +44 1223 336033 or e-mail: deposit@ccdc.cam.ac.uk.
3
Yield: (80%); a red-brown solid; m.p. > 216 ꢁC (dec.).
Anal. Calc. for C38H37ClFeNOPPd: C, 60.66; H, 4.96; N,
1.86. Found: C, 60.38; H, 4.89; N, 1.82%. FT-IR (KBr):
3073(w), 2909(w), 1609(s), 1510(s), 1435(s), 1303(m),
1247(s), 1178(s), 1096(s), 1033(m), 997(m), 806(s),
691(s) cmÀ1
.
1H NMR(CDCl3): d 2.81(s, 3H, H19),
3.50(m, 2H, H12), 3.65(m, 2H, H11), 3.43(s, 3H, OCH3),
3.74(s, 5H, g5-C5H5), 3.76(d, 1H, H5), 3.77(m, 1H, H4),
3.84(bs, 1H, H3), 6.80(d, 2H, H15, H17), 6.95(d, 2H,
H14, H18), 7.38–7.67(m, 15H, PPh3).
Acknowledgement
We are grateful to the Natural Science Foundation of
Tianjin Metropolis (Project No. 033609011) and the Open-
ing Fund from the State Key Laboratory of Elemento-or-
ganic Chemistry, Nankai University, People’s Republic of
China for financial support for this project.
3.5.2. [PdCl(PPh3){(g5-C5H5)Fe(g5-C5H3CH2N(CH3)-
CH2C6H5)}] (5b)
Yield: (80%); a red-brown solid; m.p. > 221 ꢁC (dec.).
Anal. Calc. for C37H35ClFeNPPd: C, 61.52; H, 4.88; N,
1.94. Found: C, 61.32; H, 4.81; N, 1.96%. FT-IR (KBr):
3090(w), 2932(w), 1595(w), 1490(m), 1450(s), 1103(s),
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