Metal complexes with mono- and bis{[bis(2-pyridyl)amino]carbonyl}ferrocene ligands

Article abstract of DOI:10.1002/ejic.200800286

The ligands {[bis(2-pyridyl)amino]carbonyl}ferrocene (L1) and 1,1′-bis{[bis(2-pyridyl)amino]carbonyl}ferrocene (L2) have been prepared by treatment of the mono- or 1,1′-bis(chlorocarbonyl)ferrocene derivatives with dipyridylamine in a 1:1 or 1:2 ratio, respectively. The ligand properties of these compounds towards group 11 and palladium complexes have been studied. Ligand L1 coordinates to these compounds to give four-coordinate [Cu(L1) ₂]⁺, [PdCl₂(L1)] and [Ag(OTf)(L1)(PR ₃)] or three-coordinate [Ag(OTf)(L1)] and [Au(C₆F ₅)(L1)] compounds. The ligand coordinates in a chelate fashion in all cases. The reactivity of L2 is somewhat different because coordination to copper or silver atoms can take place through several pyridine units either from different cyclopentadienido rings, as in [Cu(L2)]⁺, [Ag ₂(OTf)₂-(L2)] and [Ag(OTf)(L2)(PPh₃)], or from the same cyclopentadienido ring, as in [Ag₂(OTf)₂(L2) (PPh₃)₂]. Coordination as a bridging ligand for four gold atoms has also been achieved in [Au₄(C₆F₅) ₄(L2)] and [Au₄(L2)(PPh₃)₄](OTf) ₄. The ligands and some complexes have been characterized by X-ray diffraction studies and show the presence of several hydrogen bonds that lead to supramolecular structures. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.

Full text of DOI:10.1002/ejic.200800286

FULL PAPER
DOI: 10.1002/ejic.200800286
Metal Complexes with Mono- and Bis{[bis(2-pyridyl)amino]carbonyl}ferrocene
Ligands
Javier E. Aguado,[a] Olga Crespo,[a] M. Concepción Gimeno,*[a] Peter G. Jones,[b]
Antonio Laguna,[a] and Yolanda Nieto[a]
Keywords: Gold / Silver / Copper / Sandwich complexes / N ligands
The ligands {[bis(2-pyridyl)amino]carbonyl}ferrocene (L1)
and 1,1Ј-bis{[bis(2-pyridyl)amino]carbonyl}ferrocene (L2)
have been prepared by treatment of the mono- or 1,1Ј-
bis(chlorocarbonyl)ferrocene derivatives with dipyridyl-
amine in a 1:1 or 1:2 ratio, respectively. The ligand properties
of these compounds towards group 11 and palladium com-
plexes have been studied. Ligand L1 coordinates to these
compounds to give four-coordinate [Cu(L1)2]+, [PdCl2(L1)]
and [Ag(OTf)(L1)(PR3)] or three-coordinate [Ag(OTf)(L1)]
and [Au(C6F5)(L1)] compounds. The ligand coordinates in a
chelate fashion in all cases. The reactivity of L2 is somewhat
different because coordination to copper or silver atoms can
take place through several pyridine units either from dif-
ferent cyclopentadienido rings, as in [Cu(L2)]+, [Ag2(OTf)2-
(L2)] and [Ag(OTf)(L2)(PPh3)], or from the same cyclo-
pentadienido ring, as in [Ag2(OTf)2(L2)(PPh3)2]. Coordination
as a bridging ligand for four gold atoms has also been
achieved in [Au4(C6F5)4(L2)] and [Au4(L2)(PPh3)4](OTf)4. The
ligands and some complexes have been characterized by X-
ray diffraction studies and show the presence of several hy-
drogen bonds that lead to supramolecular structures.
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2008)
ferrocene moieties and the varying coordination numbers
of metal ions. Several reports have dealt with the synthesis
of ferrocene-based bidentate ligands that contain pyridine
moieties and their interesting coordination properties.[18]
1,1Ј-Bis(4-pyridyl)ferrocene, for example, gives supramolec-
ular heterometallic metallamacrocycles.[19] Supramolecular
networks resulting from coordination or weak hydrogen
bonding have also been achieved with other substituted fer-
rocenes with azolate ligands.[20]
Continuing our studies in this field, in which we have
described several ferrocene ligands that show interesting co-
ordination properties and, in some cases, supramolecular
motifs through weak hydrogen bonds,[21–27] we report here
the synthesis of two (aminocarbonyl)ferrocene derivatives
that contain several pyridine groups. The coordination
properties of these ligands towards group 11 metals and
palladium have been studied. They can act as bidentate or
tetradentate chelating or bridging ligands. The structurally
characterized derivatives show supramolecular structures
through weak hydrogen bonding involving the oxygen, flu-
orine and/or chlorine atoms.
Introduction
Ferrocene is a very versatile molecule with important
properties such as high electron density, aromaticity and re-
dox reversibility. These characteristics, together with the
ease of preparation of mono- and 1,1Ј-disubstituted ferro-
cene derivatives with a great variety of organic fragments
that may contain O, N, S, P, etc. as donor atoms, make
ferrocene an ideal building block in many fields of re-
search.[1–3] Current areas of interest in ferrocene chemistry
include its use in catalysis, materials and bioinorganic
chemistry. These functionalized ferrocene derivatives and
the study of their coordination to metal centres are an im-
portant topic of research in many areas that seek special
properties for such species, especially nonlinear optical
properties, charge transport, liquid crystals, electrochemical
recognition, catalysis, nanoparticles, immunoassay reagents
or biological applications.[1–17]
The introduction of a ferrocene group into supramolec-
ular coordination systems not only incorporates a redox-
active group but could also lead to interesting assembled
structures because of the conformational flexibility of the
[a] Departamento de Química Inorgánica, Instituto de Ciencia de
Materiales de Aragón,
Results and Discussion
Universidad de Zaragoza – C.S.I.C.,
The ligands {[bis(2-pyridyl)amino]carbonyl}ferrocene
(L1) and 1,1Ј-bis{[bis(2-pyridyl)amino]carbonyl}ferrocene
(L2) were prepared by treatment of the mono- or 1,1Ј-
bis(chlorocarbonyl)ferrocene derivatives with dipyridyl-
amine, in a 1:1 or 1:2 molar ratio, respectively, in dichloro-
50009 Zaragoza, Spain
[b] Institut für Anorganische und Analytische Chemie der Tech-
nischen Universität,
Postfach 3329, 38023 Braunschweig, Germany
Supporting information for this article is available on the
WWW under http://www.eurjic.org or from the author.
Eur. J. Inorg. Chem. 2008, 3031–3039
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J. E. Aguado, O. Crespo, M. C. Gimeno, P. G. Jones, A. Laguna, Y. Nieto
FULL PAPER
methane in the presence of NEt3 [see Equations (1) and (2)]. for the equivalent pyridine moieties. The molecular peak in
The IR spectrum of L1 shows a ν(C=O) absorption for the the mass spectrum (LSIMS+) appears at m/z (%) = 383
amide group at 1674 cm–1 and ν(C=N) absorptions at 1558 (100). The ligand L2 also shows the ν(C=O) absorption of
1
and 1567 cm–1. The 1H NMR spectrum shows two mul- the amide group at 1670 cm–1 in its IR spectrum. The H
tiplets for the α- and β-protons of the substituted cyclopen- NMR spectrum contains two multiplets for the α- and β-
tadienido group, a singlet for the protons of the unsubsti- protons of the cyclopentadienido groups and four reso-
tuted cyclopentadienido ring and four typical resonances nances for the pyridine units. The mass spectrum shows the
molecular peak with an additional proton at m/z (%) = 581
(20).
The structures of both ligands were established by X-
ray diffraction. Selected bond lengths and angles and the
drawings of the molecules are available as Supporting Infor-
mation. The cyclopentadienido rings in L1 are almost
eclipsed, and the pyridine units are almost perpendicular to
each other (interplanar angle 98.7°). The bond lengths and
angles are typical of this type of compounds. There are sev-
eral contacts between the oxygen atom and the protons of
the cyclopentadienido or pyridine rings in the range 2.37–
2.60 Å with angles close to 180°; these can be classified as
hydrogen bonds (Table 1) and lead to a supramolecular net-
work. The shortest one [O1···H16 2.370(1) Å] leads to the
formation of chains (Figure 1). The molecule of L2 shows
crystallographic twofold symmetry with the two bis(2-pyr-
idyl)amino units in the ferrocene moiety staggered by 72°.
Table 1. Hydrogen bonds for L1, L2, 6 and 8 [Å and °].
d(H···A)
d(D···A)
Ͻ(DHA)
L1
C(5)–H(5)···O(1)#1
2.60
2.37
3.463(2)
3.267(2)
150.9
157.3
C(16)–H(16)···O(1)#2
Symmetry transformations used to generate equivalent atoms: #1:
x, y + 1, z; #2: x, –y, z – 1/2.
L2
C(16)–H(16)···N(22)#1
C(23)–H(23)···O#2
C(15)–H(15)···O#3
Symmetry transformations used to generate equivalent atoms:
#1: –x + 1, y, –z + 1/2; #2: x, –y + 1, z – 1/2; #3: –x + 1, –y + 1,
–z + 1.
2.59
2.63
2.67
3.395(2)
3.546(2)
3.609(2)
143.1
162.8
168.1
Figure 1. Formation of chains through hydrogen bonds (dotted
lines) in L1.
Complex 6
C(15)–H(15)···O(1)#1
C(22)–H(22A)···Cl(1)#2
C(18)–H(18)···Cl(2)#2
C(20)–H(20)···Cl(3)#3
C(21)–H(21)···Cl(1)#4
C(16)–H(16)···Cl(3)#1
2.48
2.85
2.87
2.84
2.87
2.87
3.259(4)
3.669(4)
3.524(3)
3.645(3)
3.510(3)
3.595(4)
138.7
140.9
126.8
142.6
125.5
133.4
Symmetry transformations used to generate equivalent atoms:
#1: –x, –y + 1, –z + 1; #2: x + 1, y, z; #3: x, y, z – 1; #4: –x, –y
+ 1, –z.
Complex 8
C(9)–H(9)···O(1)#1
C(3)–H(3)···O(2)#2
C(4)–H(4)···O(4)#2
C(8)–H(8)···F(1)#2
C(53)–H(53)···O(3)
C(33)–H(33)···O(5)
2.53
2.37
2.48
2.45
2.35
2.57
3.408(5)
3.223(5)
3.403(5)
3.241(5)
3.096(5)
3.309(6)
154.2
149.0
164.5
140.7
135.4
134.3
Symmetry transformations used to generate equivalent atoms:
Figure 2. Chains of molecules parallel to the z axis formed by hy-
drogen bonds (dotted lines) in L2.
#1: –x, –y, –z + 1; #2: –x + 1, –y, –z + 1.
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Metal Complexes with {[Bis(2-pyridyl)amino]carbonyl}ferrocene Ligands
The two carbonyl groups point to the inside of the ferro- at –55 °C due to coupling of the phosphorus atoms with
cene moiety, with the pyridine rings perpendicular to them. the two silver nuclei 107Ag and 109Ag.
The C=O and N–C distances are normal for this type of
The reaction of L1 with 1 equiv. of [Au(C6F5)(tht)] gives
compound. This molecule also contains several hydrogen the complex [Au(C6F5)(L1)] (5) in which the ligand may be
bonds with the oxygen atom as acceptor. The contacts acting in a chelating mode to afford a three-coordinate
1
O···H15 (2.65 Å) and O···H23 (2.63 Å) combine to form gold(I) derivative. The H NMR spectrum of 5 shows that
chains of molecules parallel to the z axis (Figure 2).
the resonances for both pyridine groups are equivalent,
The reaction of L1 with [Cu(NCMe)4]PF6 in a 2:1 molar which is consistent with a trigonal-planar disposition for
ratio gives the complex [Cu(L1)2]PF6 (1). We assume that the gold centre. The 19F NMR spectrum shows the three
the structure corresponds to a four-coordinate copper atom typical resonances for a pentafluorophenyl ring (two mul-
with a tetrahedral geometry (Scheme 1). The 1H NMR tiplets for the ortho- and meta-fluorine atom and a triplet
spectrum shows broad resonances with chemical shifts dif- for the para-fluorine atom). The mass spectrum contains
ferent from those of the uncoordinated ligand. The mass the molecular peak at m/z (%) = 747 (80).
spectrum shows the cationic molecular peak [Cu(L1)2]+ at
Treatment of L1 with [PdCl2(NCPh)2] in a 1:1 molar
m/z (%) = 829 (95). Treatment of L1 with Ag(OTf) in a 1:1 ratio leads to the complex [PdCl2(L1)] (6), by displacement
molar ratio gives the mononuclear complex [Ag(OTf)(L1)] of the benzonitrile ligands, in which the ligand coordinates
(2), whose spectroscopic data are consistent with the coor- as a chelate. The 1H NMR spectrum of this complex shows
dination of the silver centre to the ligand, presumably the typical resonances for the coordinated ligand. The mass
through the nitrogen atoms of the pyridine moieties and the spectrum contains the molecular peak at m/z (%) = 561
oxygen atom of the triflate anion. The mass spectrum shows (65).
the cationic molecular peak [Ag(L1)]+ at m/z (%) = 490
The structure of complex 6 was confirmed by X-ray dif-
(55). Treatment of the ligand with the silver complex [Ag- fraction (Figure 3). A selection of bond lengths and angles
(OTf)(PR3)] gives the four-coordinate species [Ag(OTf)- are collected in Table 2. The coordination of the palladium
(L1)(PR3)] [PR3 = PPh3 (3), PPh2Me (4)] in high yields. centre is square-planar with very regular angles, with the
Complexes 3 and 4 show two multiplets for the α- and β- largest deviation corresponding to the N–Pd–N angle
protons of the substituted cyclopentadienido rings, a singlet [86.54(10)°]. The Pd–Cl [2.2801(8) and 2.2906(9) Å] and
for the protons of the unsubstituted cyclopentadienido Pd–N distances [2.029(3) and 2.034(3) Å] are similar to
units and resonances for the pyridine and phenyl protons those found in other palladium complexes, and the cyclo-
in their 1H NMR spectra. Compound 4 also shows a broad pentadienido rings are almost ideally staggered. There are
resonance for the methyl protons coupled to the phospho- several secondary bonds that can be classified as hydrogen
rus atom. The 31P{1H} NMR spectrum contains a broad bonds, as, for example, those formed between the oxygen
resonance at room temperature that splits into two doublets atom and one of the protons of a pyridine ring (H15) of
Scheme 1. (i) 1/2 [Cu(NCMe)4]PF6, (ii) Ag(OTf), (iii) [Ag(OTf)(PR3)], (iv) [Au(C6F5)(tht)], (v) [PdCl2(NCPh)2].
Eur. J. Inorg. Chem. 2008, 3031–3039
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J. E. Aguado, O. Crespo, M. C. Gimeno, P. G. Jones, A. Laguna, Y. Nieto
FULL PAPER
2.485 Å (H···O), which leads to the formation of dimers
(Figure 4), or those involving the chlorine atoms bound to
the palladium atom and the dichloromethane solvent,
which leads to a three-dimensional network.
Figure 4. Some hydrogen bonds in complex 6.
two pyridine groups of different ligands. The IR spectrum
of compound 8 shows the presence of coordinated triflate
ligands, with νs(SO3) absorptions at 1273 and 1255 (vs),
νs(CF3) absorptions at 1231 (s), νas(CF3) absorptions at
1166 (s) and νs(SO3) absorptions at 1046 cm–1 (s). The α-
Figure 3. Molecular structure of complex 6 showing the atom-num-
bering scheme. Displacement parameter ellipsoids represent 50%
probability surfaces. Hydrogen atoms and solvent molecules have
been omitted for clarity.
1
and β-protons appear as two multiplets in the H NMR
spectrum, thereby indicating that both cyclopentadienido
rings are equivalent. There are also three resonances for the
pyridine protons, some of which are overlapped.
Table 2. Selected bond lengths [Å] and angles [°] for complex 6.
The structure of complex 8 was confirmed by X-ray dif-
fraction and is shown in Figure 5. No short argentophilic
interaction is present [Ag(1)–Ag(2) 3.461 Å]. Each silver
atom is bonded to two nitrogen atoms of the pyridine rings
of different bis(2-pyridyl)amino units that are staggered by
61.5° (72° in L2). The geometry around the silver atoms is
Pd–N(2)
2.029(3)
2.034(3)
2.2801(8)
2.2906(9)
86.54(10)
176.60(8)
91.09(7)
90.50(8)
174.42(8)
92.07(3)
114.9(3)
116.4(3)
119.5(2)
121.8(2)
Pd–N(3)
Pd–Cl(2)
Pd–Cl(1)
N(2)–Pd–N(3)
N(2)–Pd–Cl(2)
N(3)–Pd–Cl(2)
N(2)–Pd–Cl(1)
N(3)–Pd–Cl(1)
Cl(2)–Pd–Cl(1)
N(2)–C(12)–N(1)
N(3)–C(17)–N(1)
C(12)–N(2)–Pd
C(16)–N(2)–Pd
The reactivity of L2 towards group 11 metals has also
been studied (Scheme 2). Thus, the treatment of L2 with
1 equiv. of [Cu(NCMe)4]PF6 gives a compound of stoichi-
ometry [Cu(L2)]PF6 (7). The ligand possesses four pyridine
groups that can coordinate to the copper centre in a tetra-
hedral geometry, thereby acting as a tetradentate ligand.
The IR spectrum of 7 shows the absorption of the hexafluo-
rophosphate anion at 884 cm–1 (vs) and the ν(C=O) absorp-
1
tion at 1667 cm–1 (s). The H NMR spectrum shows two
multiplets for the α- and β-protons of the cyclopentadienido
rings and one unique broad multiplet for the pyridine pro-
tons. The mass spectrum shows the cationic molecular peak
at m/z (%) = 644 (75).
Figure 5. Molecular structure of compound 8 showing the atom-
numbering scheme. Displacement parameter ellipsoids represent
30% probability surfaces. Hydrogen atoms have been omitted for
The reaction of L2 with 2 equiv. of Ag(OTf) gives [Ag2-
(OTf)2(µ-L2)] (8), in which each silver centre is bonded to clarity. Only one position of the disordered triflate group is shown.
3034 Eur. J. Inorg. Chem. 2008, 3031–3039
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Metal Complexes with {[Bis(2-pyridyl)amino]carbonyl}ferrocene Ligands
Scheme 2. (i) 1/2 [Cu(NCMe)4]PF6, (ii) 2 Ag(OTf), (iii) [Ag(OTf)(PPh3)], (iv) 2 [Ag(OTf)(PPh3)], (v) 4 [Au(C6F5)(tht)], (vi) 4 [Au(-
OTf)(PPh3)].
slightly distorted from linear [N(32)–Ag(1)–N(52) 178.03°, Table 3. Selected bond lengths [Å] and angles [°] for compound 8;
see Table 1 for definition of symmetry operations used to generate
equivalent atoms.
N(42)–Ag(2)–N(22) 161.37°; Table 3]. This distortion is
probably due to the coordination of each silver atom to one
Ag(1)–N(32)
Ag(1)–O(3)
Ag(2)–N(22)
Ag(2)–N(42)
Ag(2)–O(6)
Ag(1)–N(52)
N(32)–Ag(1)–N(52)
N(32)–Ag(1)–O(3)
N(52)–Ag(1)–O(3)#1
N(22)–Ag(2)–N(42)
N(22)–Ag(2)–O(6)
N(42)–Ag(2)–O(6)
2.159(3)
2.641(13)
2.165(3)
2.164(3)
2.572(9)
2.171(3)
178.03(12)
94.63(11)
86.91(11)
161.41(12)
110.9(2)
86.4(2)
oxygen atom belonging to one triflate group. The triflate
group bonded to Ag2 is disordered, and the Ag(2)–O(6)
distance in Table 3 should be interpreted with caution (see
refinement, special details). The Ag(1)–O(3) distance
[2.641(3) Å] is shorter than those in [Ag(PPh2Me)2](OTf)
[Ag–O 2.775(2), 2.854(2) Å][28] and longer than that found
in [Ag(H2O)L]2(NO3)2 [2.592(2) Å; L = 1,4-bis(2-pyridoxy)-
benzene],[29a] in which the silver atoms are coordinated to
two nitrogen atoms of pyridine rings and an oxygen atom
of a water molecule. In this case, there are also weaker con-
tacts between each atom of the pyridoxy unit with one sil-
ver atom (ca. 2.9 Å). These contacts are also observed in 8
[Ag(1)–O(2) 2.961, Ag(2)–O(1) 3.074 Å]. The Ag–N dis- Among them, those formed by the amide oxygen atoms join
tances in [AgL(NO3)]2 [L = 1,4-bis(2-pyridylsulfanylmeth- the molecules in an almost head (the part of the molecule
yl)benzene;[29b] 2.166(2), 2.165(2) Å] are longer than those with the ferrocene unit)-to-tail fashion. The result is the for-
in 8 [2.159(3)–2.171(2) Å]. The bond lengths in the ferro- mation of chains in which the angle between the plane
cene ligand L2 are similar to those observed in 8. The C=O formed by the two silver atoms and the two hydrogen atoms
distances in 8 are very similar [1.216(5) and 1.214(5) Å] and (O1, H9, O1A, H9A) with the plane formed by atoms O2,
shorter than that in L2 [1.227(2) Å]. The coordination to H3, O2B and H3B is 78.4° (Figure 6). Two different triflate
the silver atoms seems to have no significant effect on the ligands complete the pattern. One of these belongs to the
N–C distances or the C–N–C angles.
same asymmetric unit and uses O5, as well as O3 (also
Some hydrogen bonds (Table 1) of the type C–H···O and bonded to Ag1), to form hydrogen bonds with the hydrogen
C–H···F (H···O distances between 2.35 and 2.57 Å; H···F atoms of one pyridine ring. The other triflate group belongs
distance 2.45 Å) have been found (those involving the oxy- to the same asymmetric unit as that involved in O2···H3
gen atoms of the disordered triflate are not considered). hydrogen bonds and uses O4 and F1 to form hydrogen
Eur. J. Inorg. Chem. 2008, 3031–3039
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J. E. Aguado, O. Crespo, M. C. Gimeno, P. G. Jones, A. Laguna, Y. Nieto
FULL PAPER
Figure 6. Formation of chains through hydrogen bonding (dotted lines) in complex 8.
bonds with the hydrogen atoms of the ferrocene rings. C– sorption at 1652 cm–1; the most significant absorptions for
H···X interactions, although weaker than strong hydrogen compound 10 are those due to the triflate anion and
bonds with oxygen or nitrogen atoms, have been classified ν(C=O). The 1H NMR spectra contain one (11) or two
as real hydrogen bonds.[30]
multiplets (12) for the α- and β-protons of the cyclopen-
The reaction of L2 with [Ag(OTf)(PPh3)] was carried out tadienido units and four multiplets for the equivalent pyr-
in a 1:1 and 1:2 molar ratio to give the compounds [Ag- idine protons in each case. Compound 11 shows three reso-
(OTf)(L2)(PPh3)] (9) and [Ag2(OTf)2(L2)(PPh3)2] (10), nances in its 19F NMR spectrum, thereby indicating the
respectively. There are two possibilities for the structure of equivalence of the pentafluorophenyl groups. The 31P{1H}
complex 9: the silver centre coordinates to two pyridine NMR spectrum of complex 12 contains a singlet at δ =
rings of one of the substituted cyclopentadienido ligands, 29.8 ppm due to the equivalent phosphorus atoms whose
or the silver atom coordinates to two pyridine units from chemical shift is typical of N–Au–P units.
different cyclopentadienido groups. The first case would
give nonequivalent cyclopentadienido units and pyridine
groups. This situation is not observed in the 1H NMR spec-
trum; therefore, we propose a structure in which the silver
centre is coordinated to two pyridine units from different
cyclopentadienido substituents for complex 9. A coordina-
tion similar to that in complex 8 is possible for compound
10, in other words coordination to pyridine units from dif-
ferent substituents, but the presence of a bulky ligand such
as PPh3 could promote coordination to pyridine moieties
from the same cyclopentadienido units in an antiperiplanar
fashion. The bands due to the trifluoromethanesulfonate
anion in the IR spectra suggest that it is covalent. In both
Conclusions
The ligands {[bis(2-pyridyl)amino]carbonyl}ferrocene
(L1) and 1,1Ј-bis{[bis(2-pyridyl)amino]carbonyl}ferrocene
(L2) show different coordination modes in their coordina-
tion to copper, silver, gold and palladium. In the complexes
studied L1 always acts as a bidentate chelating ligand,
whereas the coordination of L2 is governed by the metal
and the stoichiometric ratio. Thus, with copper it acts as a
tetradentate chelate, with silver as a bidentate chelate and
with gold as a tetradentate bridging ligand. The presence
of secondary interactions, such as weak hydrogen bonds of
the type C–H···O, C–H···N or C–H···X (X = F, Cl), which
lead to supramolecular networks in the structures of some
of these derivatives, is noteworthy.
1
cases the H NMR spectra show two multiplets for the α-
and β-protons of the cyclopentadienido groups, thereby in-
dicating that they are equivalent, along with several mul-
tiplets, some of which are overlapped, for the pyridine pro-
tons. The 31P{1H} NMR spectra show one broad resonance
at room temperature that splits into two doublets at –90 °C
in dichloromethane as a consequence of the coupling of the
phosphorus atoms with the silver nuclei.
Experimental Section
Instrumentation: Infrared spectra were recorded in the range 4000–
200 cm–1 with a Perkin–Elmer 883 spectrophotometer as Nujol
mulls between polyethylene sheets. Conductivities were measured
in ca. 5ϫ10–4  acetone solutions with a Philips 9509 conductim-
eter. C, H, N and S analyses were performed with a Perkin–Elmer
2400 microanalyzer. Mass spectra were recorded with a VG Au-
tospec, with the liquid secondary-ion mass spectra (LSIMS) tech-
nique, using nitrobenzyl alcohol as matrix. NMR spectra were re-
Finally, the reactions of L2 with the gold derivatives
[Au(C6F5)(tht)] (tht = tetrahydrothiophene) and [Au(OTf)-
(PPh3)] in a 1:4 molar ratio were carried out to afford the
tetranuclear gold species [Au4(C6F5)4(µ-L2)] (11) and
[Au4(µ-L2)(PPh3)4](OTf)4 (12). The IR spectrum of 11
shows absorptions due to the pentafluorophenyl groups at
1505 (vs), 954 (vs) and 799 cm–1 (s) together a ν(C=O) ab- corded with a Varian Unity 300 spectrometer and a Bruker ARX
3036 Eur. J. Inorg. Chem. 2008, 3031–3039
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© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Metal Complexes with {[Bis(2-pyridyl)amino]carbonyl}ferrocene Ligands
300 spectrometer in CDCl3, unless otherwise stated. Chemical
shifts are cited relative to SiMe4 (1H, external), CFCl3 (19F, exter-
nal) and 85% H3PO4 (31P, external).
(m, 4 H, α-C5H4), 4.03 (s, 4 H, C5H5), 3.93 (m, 4 H, β-C5H4), 7.38
(m, 2 H, py), 7.41 (m, 17 H, py + Ph), 7.88 (m, 2 H, py), 8.69 (m,
2 H, py) ppm. 31P(1H) NMR: δ = 14.5 (2 d, JAg,P = 738.1 and
651.8 Hz, PPh3) ppm. Complex 4: Yield: 0.058 g (69%). ΛM
=
Starting Materials: The starting materials Fc(COCl),[31] Fc-
(COCl)2,[32] [Au(C6F5)(tht)],[33] [Ag(OTf)(PR3)],[28] [Cu(NCMe)4]-
PF6,[34] and [PdCl2(NCPh)2][35] were prepared according to pub-
lished procedures. [Au(OTf)(PPh3)] was obtained by treatment of
[AuCl(PPh3)][36] with Ag(OTf) in dichloromethane and used in situ.
All other reagents were commercially available.
85 Ω–1 cm2 mol–1. C35H30AgF3FeN3O4PS (840.37): calcd. C 50.02,
1
H 3.60, N 5.0, S 3.81; found C 50.17, H 3.69, N 4.85, S 3.58. H
NMR: δ = 2.15 (m, 3 H, Me), 4.26 (m, 4 H, α-C5H4), 4.33 (s, 4 H,
C5H5), 4.38 (m, 4 H, β-C5H4), 7.50 (m, 17 H, py + Ph), 7.72 (m, 2
H, py), 8.09 (m, 2 H, py), 8.65 (m, 2 H, py). 31P(1H), δ = –4.1 (2
d, JAg,P = 759.1 and 658 Hz, PPh3) ppm.
Synthesis of L1: NEt3 (0.61 mL, 1 mmol) was added to a solution
of HN(py)2 (0.712 g, 1 mmol) in dichloromethane (20 mL) under
argon, and a solution of FcCOCl (0.248 g, 1 mmol) in dichloro-
methane (20 mL) was added dropwise at 0 °C. When the addition
was complete, the solution was stirred at 0 °C for 1 h, and the mix-
ture was left to react for 24 h. After chromatography on alumina,
with a dichloromethane/ethanol (99:1) mixture as eluent, L1 was
Synthesis of [Au(C6F5)(L1)] (5): [Au(C6F5)(tht)] (0.045 g, 0.1 mmol)
was added to a solution of L1 (0.038 g, 0.1 mmol) in dichlorometh-
ane (20 mL), and the mixture was stirred for 1 h. Evaporation of
the solvent to ca. 5 mL and addition of n-hexane gave complex 5
as a yellow solid. Yield: 0.066 g (80%). ΛM = 4.5 Ω–1 cm2 mol–1.
C33H17AuF5FeN3O (819.31): calcd. C 43.39, H 2.29, N 5.62; found
C 43.68, H 2.37, N 5.86. 1H NMR: δ = 4.34 (m, 9 H, C5H4
+
obtained as
a
red solid. Yield: 0.182 g (49%). ΛM
=
C5H5), 7.34 (m, 2 H, py), 7.69 (m, 2 H, py), 7.88 (m, 2 H, py), 8.51
(m, 2 H, py) ppm. 19F NMR: δ = –116.0 (m, 2 F, o-F), –159.9 (t,
3JF,F = 20.9 Hz, 1 F, p-F), –163.4 (m, 2 F, m-F) ppm.
0.1 Ω–1 cm2 mol–1. C21H17FeN3O (383.22): calcd. C 65.81, H 4.47,
1
N 10.96; found C 65.51, H 4.27, N 10.93. H NMR: δ = 4.21 (m,
4 H, C5H4), 4.27 (m, 9 H, C5H4 + C5H5), 7.16 (m, 2 H, py), 7.36
(m, 2 H, py), 7.70 (m, 2 H, py), 8.42 (m, 2 H, py) ppm.
Synthesis of [PdCl2(L1)] (6): [PdCl2(NCPh)2] (0.038 g, 0.1 mmol)
was added to a solution of L1 (0.038 g, 0.1 mmol) in dichlorometh-
ane (20 mL), and the mixture was stirred for 1 h. Evaporation of
the solvent to ca. 5 mL and addition of n-hexane gave complex 6
Synthesis of L2: NEt3 (0.42 mL, 4.2 mmol) was added to a solution
of HN(py)2 (0.684 g, 4 mmol) in dichloromethane (20 mL) under
argon, and a solution of 1,1Ј-bis(chlorocarbonyl)ferrocene (0.510 g,
2 mmol) in dichloromethane (20 mL) was added dropwise at 0 °C.
When the addition was complete, the solution was stirred at 0 °C
for 1 h, and the mixture was left to react for 24 h. After chromatog-
raphy on alumina, using a dichloromethane/ethanol (95:5) mixture
as eluent, L2 was obtained as a red solid. Yield: 0.371 g (32%).
ΛM = 1.1 Ω–1 cm2 mol–1. C32H24FeN6O2 (580.41): calcd. C 66.21,
as
a
yellow-orange solid. Yield: 0.070 g (92%). ΛM
=
11 Ω–1 cm2 mol–1. C21H17AuCl2FeN3OPd (757.51): calcd. C 44.99,
H 3.05, N 7.49; found C 44.78, H 2.97, N 7.16. 1H NMR: δ = 4.35
(m, 2 H, α-C5H4), 4.40 (m, 2 H, β-C5H4), 4.50 (s, 5 H, C5H5), 7.46
(m, 2 H, py), 7.63 (m, 2 H, py), 7.93 (m, 2 H, py), 9.10 (m, 2 H,
py) ppm.
1
H 4.16, N 14.48; found C 66.34, H 4.19, N 14.22. H NMR: δ =
Synthesis of [Cu(L2)]PF6 (7): [Cu(NCMe)4]PF6 (0.038 g, 0.1 mmol)
was added to a solution of L2 (0.058 g, 0.1 mmol) in dichlorometh-
ane (20 mL) under argon. The mixture was stirred for 1 h, and then
evaporation of the solvent to ca. 5 mL and addition of diethyl ether
4.31 (m, 4 H, α-C5H4), 4.40 (m, 4 H, β-C5H4), 7.16 (t, JH,H
=
5.84 Hz, 4 H, py), 7.70 (t, JH,H = 7.21 Hz, 4 H, py), 7.30 (d, JH,H
= 8.24 Hz, 4 H, py), 8.43 (m, 4 H, py) ppm.
gave complex 7 as an orange solid. Yield: 0.047 g (60%). ΛM
=
Synthesis of [Cu(L1)2]PF6 (1): [Cu(NCMe)4]PF6 (0.038 g,
0.1 mmol) was added to a solution of L1 (0.073 g, 0.2 mmol) in
dichloromethane (20 mL) under argon. The mixture was stirred for
1 h, and then evaporation of the solvent to ca. 5 mL and addition
of diethyl ether gave complex 1 as a yellow solid. Yield: 0.073 g
(75%). ΛM = 98 Ω–1 cm2 mol–1. C42H34CuF6Fe2N6O2P (974.75):
calcd. C 51.74, H 3.51, N 8.62; found C 51.35, H 3.28, N 8.35. H
NMR: δ = 4.24 (m, 18 H, C5H4 + C5H5), 7.52 (m, 4 H, py), 7.65
(m, 4 H, py), 7.94 (m, 4 H, py), 8.41 (m, 4 H, py) ppm.
99 Ω–1 cm2 mol–1. C32H24CuF6FeN6O2P (788.92): calcd. C 48.71, H
1
3.06, N 10.65; found C 48.68, H 2.77, N 11.04. H NMR: δ = 4.01
(m, 4 H, α-C5H4), 4.39 (m, 4 H, β-C5H4), 8.42 (br. m, 8 H, py)
ppm.
Synthesis of [Ag2(OTf)2(L2)] (8): Ag(OTf) (0.051 g, 0.2 mmol) was
added to a solution of L2 (0.058 g, 0.1 mmol) in dichloromethane
(20 mL), and the mixture was stirred for 1 h. Evaporation of the
solvent to ca. 5 mL and addition of diethyl ether gave complex
8 as a yellow solid. Yield: 0.061 g (56%). C34H24Ag2F6FeN6O8S2
(1094.3): calcd. C 37.31, H 2.21, N 7.68, S 5.86; found C 37.45, H
2.46, N 8.04, S 6.07. 1H NMR: δ = 4.12 (m, 4 H, α-C5H4), 4.31
(m, 4 H, β-C5H4), 7.45 (m, 4 H, py), 7.85 (m, 8 H, py), 8.79 (m, 4
H, py) ppm.
1
Synthesis of [Ag(OTf)(L1)] (2): Ag(OTf) (0.026 g, 0.1 mmol) was
added to a solution of L1 (0.038 g, 0.1 mmol) in dichloromethane
(20 mL), and the mixture was stirred for 1 h. Evaporation of the
solvent to ca. 5 mL and addition of diethyl ether gave complex 2
as an orange solid. Yield: 0.039 g (61%). ΛM = 62 Ω–1 cm2 mol–1.
C22H17AgF3FeN3O4S (640.16): calcd. C 41.27, H 2.67, N 6.56, S
Synthesis of [Ag(OTf)(L2)(PPh3)] (9): [Ag(OTf)(PPh3)] (0.051 g,
5.01; found C 41.53, H 2.87, N 6.78, S 4.79. 1H NMR: δ = 4.40 0.1 mmol) was added to a solution of L2 (0.058 g, 0.1 mmol) in
(m, 9 H, C5H4 + C5H5), 7.38 (m, 2 H, py), 7.49 (m, 2 H, py), 7.89 dichloromethane (20 mL), and the mixture was stirred for 1 h.
(m, 2 H, py), 8.54 (m, 2 H, py) ppm.
Evaporation of the solvent to ca. 5 mL and addition of diethyl
ether gave complex 9 as a yellow solid. Yield: 0.062 g (56%).
C51H39AgF3FeN6O5PS (1099.6): calcd. C 55.70, H 3.57, N 7.64, S
2.98; found C 55.51, H 3.48, N 7.49, S 2.98. 1H NMR: δ = 4.18
(m, 4 H, α-C5H4), 4.32 (m, 4 H, β-C5H4), 7.37 (m, 15 H, py), 7.73
(m, 8 H, py), 8.48 (m, 8 H, py). 31P(1H) NMR: δ = 14.4 (2d, JAg,P
= 745 and 645 Hz, PPh3) ppm.
Synthesis of [Ag(OTf)(L1)(PR3)] [PR3 = PPh3 (3), PPh2Me (4)]:
[Ag(OTf)(PPh3)] (0.052 g, 0.1 mmol) or [Ag(OTf)(PPh2Me)]
(0.045 g, 0.1 mmol) was added to a solution of L1 (0.038 g,
0.1 mmol) in dichloromethane (20 mL), and the mixture was stirred
for 1 h. Evaporation of the solvent to ca. 5 mL and addition of
diethyl ether gave complexes 3 or 4 as yellow-orange solids.
Complex 3: Yield: 0.060 g (67%). ΛM
=
93 Ω–1 cm2 mol–1.
Synthesis of [Ag2(OTf)2(µ-L2)(PPh3)2] (10): [Ag(OTf)(PPh3)]
(0.103 g, 0.2 mmol) was added to a solution of L2 (0.058 g,
C40H32AgF3FeN3O4PS (902.44): calcd. C 53.23, H 3.57, N 4.65, S
3.55; found C 53.46, H 3.82, N 4.41, S 3.20. 1H NMR: δ = 3.93 0.1 mmol) in dichloromethane (20 mL), and the mixture was stirred
Eur. J. Inorg. Chem. 2008, 3031–3039
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
3037

J. E. Aguado, O. Crespo, M. C. Gimeno, P. G. Jones, A. Laguna, Y. Nieto
FULL PAPER
Table 4. X-ray data for complexes L1, L2, 6 and 8.
Compound
L1
L2
6·CH2Cl2
8
Empirical formula
Mr
Habit
Crystal size [mm]
Crystal system
Space group
C21H17FeN3O
383.23
yellow prism
0.22ϫ0.17ϫ0.15
monoclinic
C2/c
C32H24FeN6O2
580.42
orange prism
0.22ϫ0.07ϫ0.04
monoclinic
C2/c
C22H19Cl4FeN3OPd
645.45
C35H26Ag2Cl2F6FeN6O8S2
1179.23
orange plate
0.25ϫ0.06ϫ0.06
monoclinic
P21/n
orange prism
0.24ϫ0.20ϫ0.12
triclinic
¯
P1
a [Å]
b [Å]
c [Å]
α [°]
41.434(2)
6.4855(3)
12.8719(6)
90
104.7110(10)
90
3345.6
8
1.522
20.886(2)
9.2643(10)
15.5288(18)
90
121.626(3)
90
2558.5(5)
4
1.507
8.7095(6)
11.8124(8)
11.9898(8)
86.322(1)
69.849(1)
84.157(1)
1151.43(14)
2
12.6165(12)
18.723(2)
17.1694(18)
90
97.933(3)
90
4016.9(7)
4
1.950
β [°]
γ [°]
V [Å3]
Z
DX [Mgm–3]
1.862
1.896
µ [mm–1]
0.917
0.634
1.6
F(000)
T [°C]
1584
–173
1200
–130
640
–173
2328
–130
2θmax [°]
56.78
10404
3873
0.82–0.87
0.023
56.56
14779
3179
–
57.14
7661
5119
0.65–0.80
0.022
52
57967
8219
0.82–0.96
0.066
No. measured reflections
No. independent reflections
Transmissions
Rint
0.061
Parameters
Restraints
235
0
0.095
0.038
1.062
0.63
186
0
0.083
0.036
0.965
0.357
289
0
0.069
0.037
0.923
0.862
632
375
0.080
0.033
0.964
1.038
wR (F2, all reflections)
R [F, Ͼ4σ(F)]
S
Max. ∆ρ [eÅ–3]
for 1 h. Evaporation of the solvent to ca. 5 mL and addition of
diethyl ether gave complex 10 as a yellow solid. Yield: 0.105 g
(65%). C70H54Ag2F6FeN6O8P2S2 (1618.9): calcd. C 51.93, H 3.36,
were collected using monochromated Mo-Kα radiation (λ =
0.71073 Å). Scan type ω and φ. Absorption correction based on
multiple scans were applied with the program SADABS[37] for L1,
6 and 8. The structures were refined on F2 using the program
1
N 5.19, S 3.96; found C 52.21, H 3.56, N 5.21, S 4.11. H NMR:
δ = 4.06 (m, 4 H, α-C5H4), 4.27 (m, 4 H, β-C5H4), 7.43 (m, 38 H, SHELXL-97.[38] All non-hydrogen atoms were refined anisotropi-
py + Ph), 7.74 (m, 4 H, py), 8.50 (m, 4 H, py). 31P(1H) NMR: δ =
14.6 (2d, JAg,P = 744 and 644 Hz, PPh3) ppm.
cally. Hydrogen atoms were included using a riding model. Special
refinement details for 8: One of the triflate anions was severely
disordered. The model used in the refinement was based on two
positions, but this could be too simple, and it is not possible to
compare its coordination to silver with that of Ag1 and O3. Fur-
ther details of the data collection and refinement are given in
Table 4. CCDC-661893 (for L1), -661894 (for L2), -661895
(for 6), and -661896 (for 8) contain the supplementary crystallo-
graphic data for this paper. These data can be obtained free of
charge from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif.
Synthesis of [Au4(C6F5)4(µ-L2)] (11): [Au(C6F5)(tht)] (0.180 g,
0.4 mmol) was added to a solution of L2 (0.058 g, 0.1 mmol) in
dichloromethane (20 mL), and the mixture was stirred for 1 h.
Evaporation of the solvent to ca. 5 mL and addition of n-hexane
gave complex 11 as
a yellow solid. Yield: 0.130 g (64%).
C56H24Au4F20FeN6O2 (2036.5): calcd. C 33.02, H 1.18, N 4.12;
found C 33.30, H 1.12, N 4.41. 1H NMR: δ = 4.51 (m, 8 H, C5H4),
7.25 (m, 2 H, py), 7.68 (m, 2 H, py), 7.85 (m, 2 H, py), 8.38 (m, 2
H, py) ppm. 19F NMR: δ = –115.4 (m, 2 F, o-F), –159.8 (t, 3JF,F
19.9 Hz, 1 F, p-F), –163.1 (m, 2 F, p-F) ppm.
=
Supporting Information (see footnote on the first page of this arti-
cle): Selected bond lengths and angles and molecular structures of
L1 and L2.
Synthesis of [Au4(µ-L2)(PPh3)4](OTf)4 (12): [Au(OTf)(PPh3)]
(0.243 g, 0.4 mmol) was added to a solution of L2 (0.058 g,
0.1 mmol) in dichloromethane (20 mL), and the mixture was stirred
for 1 h. Evaporation of the solvent to ca. 5 mL and addition of n-
hexane gave complex 12 as a yellow solid. Yield: 0.238 g (79%).
C108H84Au4F12FeN6O14P4S4 (3013.7): calcd. C 43.04, H 2.80, N
Acknowledgments
We thank the Dirección General de Investigación Científica y
Técnica (CTQ2007-67273-C02-01) for financial support.
1
2.78, S 4.62; found C 43.41, H 3.07, N 2.55, S 4.49. H NMR: δ =
4.09 (m, 4 H, C5H4), 4.37 (m, 4 H, C5H4), 7.20 (m, 2 H, py), 7.37
(m, 60 H, Ph), 7.75 (m, 2 H, py), 7.88 (m, 2 H, py), 8.39 (m, 2 H, [1] Ferrocenes, Homogeneous Catalysis, Organic Synthesis and Ma-
py). 31P(1H) NMR: δ = 29.8 (s, PPh3) ppm.
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Crystal Structure Determinations: Crystals were mounted in inert
oil on glass fibers and transferred to the cold gas stream of a
Bruker Smart 1000 CCD (L2, 8) or Smart Apex CCD (L1, 6) dif-
fractometer equipped with a low-temperature attachment. Data
3038
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© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2008, 3031–3039

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