Synthesis and structural characterisation of palladium and group-12 metal complexes with a hybrid phosphanylphosphonate ferrocene ligand

Article abstract of DOI:10.1002/ejic.200500725

Diethyl [1′-(diphenylphosphanyl)ferrocenyl]phosphonate (1) was synthesised by stepwise metallation/functionalisation of 1,1′- dibromoferrocene and studied as a ligand for palladium(II) and group-12 metals. Treatment of [PdCl₂(cod)] (cod = η

Full text of DOI:10.1002/ejic.200500725

FULL PAPER
DOI: 10.1002/ejic.200500725
Synthesis and Structural Characterisation of Palladium and Group-12 Metal
Complexes with a Hybrid Phosphanylphosphonate Ferrocene Ligand
[a]
[a]
[a]
ˇ
ˇ
ˇ
ˇ
Petr Stepnicka,* Ivana Císarová, and Róbert Gyepes
Keywords: Group 12 metals / Phosphanes / Phosphonate esters / Palladium / Sandwich complexes / Structure eluicidation
Diethyl [1Ј-(diphenylphosphanyl)ferrocenyl]phosphonate (1)
was synthesised by stepwise metallation/functionalisation of
1,1Ј-dibromoferrocene and studied as a ligand for palladi-
um(II) and group-12 metals. Treatment of [PdCl2(cod)] (cod =
η2:η2-cycloocta-1,5-diene) with 1 in 1:1 or 1:2 molar ratios
gave, respectively, the dinuclear, chloride-bridged complex
[{Pd(µ-Cl)Cl(1-κP2)}2] (2) and the mononuclear complex
trans-[PdCl2(1-κP2)2] (3), where 1 coordinates exclusively
through the phosphane function. The reactions between 1
and group-12 metal bromides MBr2 in a 1:1 molar ratio gave
the adducts [MBr2(1)] [M = Zn (4), Cd (5), and Hg (6)], whose
crystal structures change considerably with the metal ion.
Thus, whereas 4 is a molecular complex with 1 coordinating
as an O1,P2-chelate, its cadmium(II) analogue is a polymer
built up from symmetric {CdBr(µ-Br)}2 units interconnected
by pairs of O1,P2-bridging phosphanylphosphonate ligands.
Finally, the mercury(II) complex 6 is a halide-bridged dimer,
[{Hg(µ-Br)Br(1-κP2)}2]. However, this compound is structur-
ally fluxional in solution (NMR spectra) and, in the crystal, it
attains a structure similar to 5 owing to weak interactions
between mercury and phosphonate-O1 atoms from adjacent
molecules. An isomer to 6, [{HgBr2(1-κ2O1,P2)}2] (7), was iso-
lated from attempted alkylation of 6 and structurally charac-
terised as a dimer, where ligands 1 bridge two {HgBr2} units.
All compounds were studied by spectroscopic methods (IR,
NMR, mass) and the solid-state structures of 1, 2·½H2O,
3·4CHCl3, 4, 5, 6·5C6H6, and 7 have been determined by
single-crystal X-ray diffraction.
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2006)
design the ferrocene phosphanylphosphonate ligand
Ph2PfcP(O)(OEt)2 (1) and study its coordination behaviour.
In this contribution, we report the synthesis, characterisa-
tion and structures of this ligand and its complexes with
palladium() and group-12 metals. It should be noted that
compound 1 was reported as an intermediate in the synthe-
Introduction
Ferrocene donors have attracted considerable attention
as valuable ligands for coordination compounds and cata-
lytic applications. Among the numerous multidentate ferro-
cene donors that have been synthesised during the last few
decades, chiral, mixed-donor (typically PN) ligands derived
from a 1,2-disubstituted ferrocene backbone have proved to
be particularly successful.[1] In contrast, the related unsym-
metrical, 1,1Ј-disubstituted ferrocene derivatives have been
studied much less.[2] This applies particularly to donors
whose asymmetry arises from the presence of two different
phosphorus groups. To date only a few ferrocene diphos-
sis of diphosphanes Ph2PfcPH2 and Ph2PfcPR2 [PR2
=
(R,R)-2,5-dimethylphospholan-1-yl] while this work was in
progress.[11] However, no investigation into its donor prop-
erties was mentioned.
Results and Discussion
phanes Ph2PfcPR2 {fc
=
ferrocene-1,1Ј-diyl; PR2
=
Diethyl [1Ј-(diphenylphosphanyl)ferrocenyl]phosphonate
(1) was prepared by lithiation of 1-bromo-1Ј-(diphenylphos-
phanyl)ferrocene followed by addition of diethyl chloro-
phosphate to the formed lithio intermediate, using the gene-
ral methodology developed by Butler et al.[7a] Subsequent
chromatography of the crude product contaminated with
(diphenylphosphanyl)ferrocene and some other minor im-
purities on alumina furnished a good yield of pure 1 as an
amber oil, which slowly crystallised upon standing at room
temperature (faster at +4 °C) to give an orange, waxy solid.
The compound was characterised by standard spectro-
scopic methods and its structure determined by X-ray dif-
fraction analysis (see Figure 1 and the section dealing with
the crystal structures below). It was then studied as a ligand
in palladium() and group-12 metal complexes.
[4]
PPh(tBu),[3] P(tBu)2,
and P(C6H4Y-4)2, Y = OMe,
CF3[5]}, phosphanylphosphonites Ph2PfcP(OR)2,[6] and
dppf semi-chalcogenides Ph2PfcP(E)R2 (E = O,[7] S, and
Se[8]) have been reported in the literature, which stands
markedly against the vast chemistry of the “popular”, sym-
metric ferrocene diphosphane 1,1Ј-bis(diphenylphosphanyl)-
ferrocene (dppf).[9]
Recent interest in the synthesis and coordination chemis-
try of ferrocene phosphonate esters and acids[10] led us to
[a] Department of Inorganic Chemistry, Faculty of Science,
Charles University,
Hlavova 2030, 12840 Prague, Czech Republic
E-mail: stepnic@natur.cuni.cz
Supporting information for this article is available on the
WWW under http://www.eurjic.org or from the author.
926
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2006, 926–938

Pd and Group-12 Metal Complexes with Hybrid Phosphanylphosphonate Ferrocene Ligand
FULL PAPER
Scheme 1.
Figure 1. Molecular structure of 1 showing the atom-labelling
scheme; for the consecutively numbered ring atoms, only labels of
the pivotal atom and its adjacent ring carbon atoms are shown for
More information about the structure of 2 was obtained
from the far-IR spectrum, which contains a strong band at
356 cm–1 (with shoulder at 350 cm–1), and several bands at
249–256 cm–1 attributable to ν(PdCl) stretching vibrations
involving the terminal and bridging chloride ligands,
respectively. An unambiguous proof of the compound
structure came from the X-ray diffraction analysis (Fig-
ure 2). Crystals amenable to the diffraction analysis were
obtained directly from the reaction mixture. However, since
the poor quality of the available crystals (disorder of the
phosphonate group and crystal defects) resulted in a rela-
tively low overall quality of the structural data, only the
most important structural features will be addressed
here.[12]
clarity (note: the atom-numbering scheme adopted for the ligand
moieties in all complexes is similar). Displacement ellipsoids are
scaled to the 30% probability level. Selected distances [Å] and
angles [°]: Fe–Cg(1) 1.6488(9), Fe–Cg(2) 177.00(5), P(1)–O(1)
1.467(2), P(1)–O(2) 1.587(2), P(1)–O(3) 1.572(2), P(1)–C(1)
1.761(2), P(2)–C(6) 1.813(2), P(2)–C(11) 1.838(2), P(2)–C(17)
1.831(2); Cg(1)–Fe–Cg(2) 177.00(5), range of O–P(1)–O angles
105.9(1)–115.7(1), range of C(1)–P(1)–O angles 98.59(9)–117.7(1),
range of C–P(2)–C angles: 100.88(9)–102.13(8), Є Cp1,Cp2 4.5(1)°,
τ[C(1)–Cg(1)–Cg(2)–C(6)] = 155.2(1)°; Cg(1) and Cg(2) are the
centroids of the cyclopentadienyl rings C(1–5) (Cp1) and C(6–10)
(Cp2), respectively.
Palladium(II) Complexes
Depending on the stoichiometry, the reaction of [Pd(cod)-
The structure determination for 2 revealed a doubly ha-
Cl2] (cod = η2:η2-cycloocta-1,5-diene) with 1 gives either lide-bridged dimeric structure with a sym-trans geometry.
the chloride-bridged dipalladium() complex trans-[{Pd(µ- Remarkably, the dihedral angle subtended by the {PdCl2P}
Cl)Cl(1-κP2)}2] (2) or the bis(phosphane) complex trans- least-squares planes is as high as 40.91(5)°, which is rather
[PdCl2(1-κP2)2] (3; Scheme 1). Attempted removal of the uncommon for compounds of this type. A search in the
chloride ligands from 3 by treatment with AgClO4 gave an Cambridge crystallographic database[13] revealed that the
intractable, dark-red, oily residue that shows broad signals observed tilting of the coordination planes is among the
in the NMR spectra.
highest observed.[14] As expected, the Pd–Cl bonds to ter-
The reaction in a 1:1 molar ratio in methanol produced minal chlorides (2.27 Å) are significantly shorter than those
a dark-red, crystalline solid, which was structurally charac- to bridging ones (2.33–2.44 Å). The Pd–P bonds in 2 are
terised as trans-[{Pd(µ-Cl)Cl(1-κP2)}2] (2). The spectro- about 0.12 Å shorter than those in 3 (see below), which can
scopic data for 2 give no clear signs about the coordination be ascribed to a lower trans influence of the chloride ligand
mode of the phosphanylphosphonate ligand and do not al- in comparison with the phosphane donor, and possibly also
low us to distinguish between two possible isomeric forms, to a less sterically strained structure of 2 where the two
namely 2 and [PdCl2(1-κ2O1,P2)]. For instance, the 1H bulky phosphanylphosphonate ligands are separated by the
NMR spectra exhibit markedly downfield-shifted ferrocene Pd(µ-Cl)2Pd core.
signals (as compared to 1 and 3) but practically unaffected
For complex 3, which is formed at a 2:1 ligand-to-metal
signals for the ethoxy groups [∆δH(CH2) Ϸ +0.03 ppm] ratio, the exclusive P-coordination of 1 is clearly manifested
whilst the 31P NMR spectra show two distinct signals at δP by a considerable shift to lower fields for the phosphanyl
= 24.6 and 31.1 ppm due to the phosphonate and phos- signal and practically unaffected phosphonate resonance
phanyl groups, respectively {coordination shifts [∆δP
=
[∆δP(PIII) = 32.3 ppm/∆δP(PV) = –0.6 ppm]. The 31P coordi-
δP(complex) – δP(ligand)] of 48.1 (PIII) and –1.1 ppm (PV), nation shifts for the palladium complexes reflect a relatively
recorded in CDCl3}.
higher trans influence of the phosphane donor (see also
Eur. J. Inorg. Chem. 2006, 926–938
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
927

ˇ
P. S teˇpnicˇka, I. Císarˇová, R. Gyepes
FULL PAPER
Figure 2. A view of the structure of complex 2 as determined for the solvate 2·½H2O. For clarity, the solvating water molecule and
hydrogen atoms have been omitted and only one orientation of the disordered phosphonate group [the group involving the P(11) atom]
is shown. Displacement ellipsoids are drawn at the 20% probability level. The atom-numbering scheme is analogous to that of 1; the first
digit is added to distinguish the symmetrically independent molecular parts. Selected distances [Å] and angles [°]: Pd(1)–Cl(11) 2.273(2),
Pd(1)–Cl(12) 2.329(2), Pd(1)–Cl(22) 2.443(2), Pd(1)–P(12) 2.229(2), Pd(2)–Cl(21) 2.273(2), Pd(2)–Cl(12) 2.415(2), Pd(2)–Cl(22) 2.325(2),
Pd(2)–P(22) 2.227(2); Cl(11)–Pd(1)–Cl(22) 92.48(5), Cl(11)–Pd(1)–P(12) 93.54(6), Cl(12)–Pd(1)–Cl(22) 83.88(5), Cl(12)–Pd(1)–P(12)
90.06(6), Cl(12)–Pd(2)–Cl(21) 91.70(6), Cl(12)–Pd(2)–Cl(22) 84.58(6), Cl(21)–Pd(2)–P(22) 88.19(7), Cl(22)–Pd(2)–P(22) 95.85(6), Pd(1)–
Cl(12)–Pd(2) 89.50(6), Pd(1)–Cl(12)–Pd(2) 88.92(5).
above), which causes the 31P NMR resonance to shift to vapour gave adducts [MBr2(1)] [M = Zn (4), Cd (5), and
higher field.[16] Simple phosphanes behave similarly; see, for Hg (6)] as air-stable, yellow-orange, crystalline solids.[18]
instance, the pair of related complexes trans-[{Pd(µ-Cl)- However, the exact formulation for these compounds as
Cl(L)}2] (∆δP = 39.5 ppm) and trans-[PdCl2L2] (∆δP
=
based on spectral evidence and crystallographic data (see
below) is rather complex and differs for all the members
29.4 ppm), where L is tri-p-tolylphosphane.[15]
The 1H NMR spectra of 3 spectra exhibit a shift to lower of the series. Thus, whereas compound 4 is a monomeric
field for all ferrocene signals but virtually no change for tetrahedral complex featuring 1 as an O,P-chelating donor,
the phosphonate ethoxy groups. The 13C NMR spectrum [ZnBr2(1-κ2O1,P2)], its cadmium analogue is a coordination
displays resonances due to the carbon atoms at the phos- polymer in which dinuclear {Cd(µ-Br)Br}2 units are linked
phanyl-substituted cyclopentadienyl and phenyl rings as into infinite chains by means of symmetric pairs of the
virtually coupled triplets arising from ABX spin systems O1,P2-bridging phosphanylphosphonate ligands (see
[12C-31P(A)-(metal)-31P(B)-13C(X)] with relatively large JA,B Scheme 2). This is reflected also by the very poor solubility
values.[16] Very similar features have been observed for the of 5 compared to the well soluble 4 and 6.
The 31P NMR spectrum of 4 is clearly indicative of O,P-
related complex with P-monodentate 1Ј-(diphenylphos-
phanyl)ferrocenecarboxylic acid (Hdpf), trans-[PdCl2(Hdpf-
κP)2].[17] The solid-state structure of the solvate 3·4CHCl3
was determined by single-crystal X-ray diffraction analysis
(see below).
chelate coordination by showing a pair of doublets at δP =
–19.9 and 26.1 ppm (3JP,P = 5 Hz) assignable to the mutu-
ally coupled phosphane and phosphonate phosphorus
atoms, respectively. The coordination shifts (∆δP) of –2.9
(PIII) and +0.4 (PV) ppm correspond favourably with the
shifts observed for [ZnCl2L] complexes with P,PЈ-chelating
Group-12 Metal Complexes
symmetric ferrocene diphosphanes [L/∆δP
=
dppf/
Mixing the phosphanylphosphonate 1 with bromides of –4.5 ppm,[19] and dippf/–6.6 ppm; dippf = 1,1Ј-bis(diisoprop-
divalent group-12 metals in a 1:1 molar ratio in acetone ylphosphanyl)ferrocene],[20] and a complex containing two
and subsequent crystallisation by diffusion of diethyl ether O1-monodentate diethyl ferrocenylphosphonate ligands,
928
www.eurjic.org
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2006, 926–938

Pd and Group-12 Metal Complexes with Hybrid Phosphanylphosphonate Ferrocene Ligand
FULL PAPER
Scheme 2. Schematic drawing of structures of the products arising from group-12 metal dibromides and 1. For compound 5, the arrows
indicate where propagation of the one-dimensional infinite polymeric chain occurs.
[ZnCl2{FcPO3Et2-κO1}2] (∆δP = +0.7 ppm in CD3OD, Fc the sample concentration (see Table 1 and Figures S1 and
= ferrocenyl).[10c] Furthermore, the coordination of the S2 in the Supporting Information). Upon raising the sam-
phosphonate group is manifested by a shift of the multiplet ple temperature, the signal due to the phosphane group
due to the OCH2 protons by about 0.3 ppm to lower field (PIII) in the 31P NMR spectrum shifts to lower fields while
1
in the H NMR spectrum.
the coupling to 199Hg increases. In contrast, the phos-
The IR spectra of 4 and 5 in the region down to about phonate resonance moves upfield with increasing tempera-
1
300 cm–1 exhibit mostly bands due to the ligand; useful in- ture. In the H NMR spectrum the major change occurs in
formation about the coordination geometry is provided by the region of the ferrocene cyclopentadienyl resonances: the
the far-IR region. In the case of 4, two bands attributable signals due to the phosphonate ethoxy groups exhibit prac-
to symmetric and antisymmetric ν(ZnBr) stretching vi- tically constant chemical shifts (note that the multiplet of
brations are observed at 219 and 251–254 cm–1, respectively, the methylene group is not entirely invariant as it becomes
close to the values reported for [ZnBr2(PPh3)2] (236 and better resolved at higher temperatures).
205 cm–1).[21] The far-IR spectrum of 5 exhibits a pair of
bands as well (at 193 and 158 cm–1). The positions of these
bands assignable to ν(CdBr) stretching vibrations involving
terminal and bridging bromide atoms correspond to those
of the binuclear, halide-bridged complex [{Cd(µ-Br)-
Br(PCy3)}2], which, however, features only tetracoordinate
cadmium centres (208 and 169–144 cm–1).[22] Notably, the
ν(ZnBr)/ν(CdBr) ratios for the band pairs (1.31 and 1.39)
correspond well to the expected value obtained from the
mass factor: [Ar(Cd)/Ar(Zn)]½ Ϸ 1.31.
Table 1. Variable temperature (VT) 31P{1H} NMR spectroscopic
data for 6.[a]
1
III
T
δ(PV)
δ(PIII
)
JHg,P
[°C]
[ppm]
[ppm]
[Hz]
[b]
+50
+25
0
–25
–50
+25[c]
23.73
23.88
24.06
24.22
24.35
23.88
–
–
24.38
23.69
23.52
23.02
24.56
6587
6702
6809
6908
6560
As revealed by X-ray analysis, compound 6 is a symmet-
ric, halide-bridged dimer with the ligand coordinating as a
simple phosphane: [{Hg(µ-Br)Br(1-κP2)}2] (Scheme 2). The
solution NMR spectroscopic data, particularly the rela-
[a] The spectra were recorded for a 0.036  solution in CDCl3. The
1
VT H and 31P{1H} NMR spectra are available as Supporting In-
formation (see Figures S1 and S2, respectively). Reference data for
1: δP = –17.0 (PIII) and 25.7 ppm (PV) (in CDCl3 at 25 °C). [b] Not
detected due to signal broadening. [c] Data for a 0.018  solution.
1
tively large JHg,P coupling constant and the coordination
shift ∆δP(PIII) of 41.4 ppm, indicate that this structure is
most likely retained in solution (cf. the parameters for
These spectral characteristics resemble in some respects
[HgBr2(PPh3)2] (1JHg,P = 4240 Hz/∆δP = 27.3 ppm) and the solution behaviour of the phosphane complexes
[{Hg(µ-Br)Br(PPh3)}2] (1JHg,P = 6450 Hz/∆δP = 32.6 ppm) [HgX2(PR3)2],[23] and are clearly indicative of structural
recorded in CDCl3/CH2Cl2, 1:1[23]). However, a detailed fluxionality. Considering the NMR and structural data (see
NMR study revealed a fluxional behaviour in solution: the below), as well as the donor ability of the ligand, the dy-
spectra of 6 change with temperature, solvent and also with namic processes occurring in solutions of [HgBr2(1)] may
Eur. J. Inorg. Chem. 2006, 926–938
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
929

ˇ
P. S teˇpnicˇka, I. Císarˇová, R. Gyepes
FULL PAPER
be formulated as shown in Scheme 3. One may expect the Crystal Structures
hybrid donor 1 to coordinate to the soft mercury atom
The crystal structure of the solvate 3·4CHCl3 (Figure 3,
Table 2) corroborates the expected trans square-planar co-
ordination of the palladium atom. The molecule of the
complex is perfectly planar and centrosymmetric due to the
imposed crystallographic symmetry. Nevertheless, owing to
the steric bulk of the P-bonded (diphenylphosphanyl)ferro-
cenyl ligands, the interligand angles deviate slightly from
the ideal value of 90°. The ferrocene units in 3 are rotated
with respect to the coordination plane by approximately
53°, which seems to minimise the steric interactions of the
bulky phosphane ligands by bringing the “PC3” moieties of
the phosphanylferrocene ligands into a close-to-staggered
conformation. This coordination geometry seems to be
common to all structurally characterised complexes
involving 1Ј-functionalised ferrocene phosphanes: trans-
[PdCl2(Ph2PfcX-κP)], where X = CO2H,[17] P(O)Ph2,[24]
SMe,[25] and (S)-4-isopropyl-4,5-dihydrooxazolyl-1-yl.[26]
more strongly through its phosphane group than through
the phosphonate oxygen. The inherent weakness of Hg–O
bonds would facilitate the formation of tricoordinate spe-
cies I which, in turn, can give rise to intermediate II (by
closure of the O,P-chelate ring with the Hg–P bond acting
as a pivot) or, by dimerisation, to the halide (6) or O,P-1-
bridged (7) dimers. As mentioned above, the NMR spectro-
scopic data indicate that the solution equilibrium is shifted
in favour of dimer 6. However, since solvent, concentration
and temperature influence the overall distribution, individ-
ual components may separate from solutions of [HgBr2(1)]
depending on their relative solubility in the reaction media
(see the structure of 7 below).
Table 2. Selected bond lengths [Å] and angles [°] for 2·4CHCl3.[a]
Pd–Cl
Pd–P(2)
P(1)–O(1) 1.467(3)
P(1)–O(2) 1.572(3)
P(1)–O(3) 1.593(3)
P(1)–C(1) 1.755(3)
P(2)–C(6) 1.802(3)
2.2984(7)
2.3467(6)
Cl–Pd–P(2)
Cl–Pd–P(2i)
O–P(1)–O[b]
86.71(2)
93.29(2)
101.3(2)–115.3(2)
C(1)–P(1)–O[c] 100.4(1)–115.6(2)
Pd–P(2)–C[d]
C–P(2)–C[e]
110.89(9)–121.1(1)
102.3(1)–104.8(1)
Fe–Cg(1)
Fe–Cg(2)
1.650(1)
1.650(1)
Є Cp1,Cp2
2.7(2)
–135.8(2)
τ[f]
[a] Symmetry operations used to generate equivalent positions: i:
–x, –y, 2 – z. Definition of the ring planes: Cp1: C(1–5); Cp(2):
C(6–1). Cg(1) and Cg(2) are the respective ring centroids. [b] The
range of O(1)–P–O(2,3) and O(2)–P(1)–O(3) angles. [c] The range
of C(1)–P(1)–O(1,2,3) angles. [d] The range of Pd–P(2)–C(6,11,17)
angles. [e] The range of C(6)–P(2)–C(11,17) and C(11)–P(2)–C(17)
angles. [f] Torsion angle C(1)–Cg(1)–Cg(2)–C(6).
Scheme 3. Schematic depiction of the exchange equilibria of
[HgBr2(1)].
Figure 3. Molecular structure of 3·4CHCl3. Displacement ellipsoids are drawn at the 30% probability level; the solvate molecules have
been omitted for clarity. Half of the molecule is generated by a (crystallographic) inversion operation, the centre of which coincides with
the palladium atom.
930
www.eurjic.org
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2006, 926–938

Pd and Group-12 Metal Complexes with Hybrid Phosphanylphosphonate Ferrocene Ligand
FULL PAPER
The ligand phosphonate groups, which do not participate lar chelate (Figure 4, Table 3). The unit cell of 4 contains
in coordination, are rotated away from the phosphanyl sub- two symmetrically independent but structurally very similar
stituent such that the disubstituted ferrocene framework molecules of the complex that differ slightly in the mutual
adopts a conformation near to anti-eclipsed with a τ angle orientation of the ferrocene ligand and the embedded
of 136° (cf. the ideal value of 144°). Due to the symmetry of ZnBr2 motif, and further by conformation of the flexible
the crystal assembly, the phosphonate groups in individual ferrocene, phenyl and ethoxy groups. The coordination
molecules are inclined towards each other, forming polar spheres around the zinc atoms in both molecules are quite
domains that accommodate the solvate: each phosphonate regularly tetrahedral, albeit with rather varying zinc–donor
moiety binds two solvent molecules by O···H–CCl3 hydro- distances: the coordination mode can be described as [3+1]
gen bonds to its phosphoryl oxygen atom [C(80)–H(80)··· with Zn–Br Ϸ Zn–P Ͼ Zn–O. The individual bond lengths
O(1i): C(80)···O(1i) 3.134(5) Å, angle at H(80) 147°; C(90)– are
H(90)···O(1i): C(90)···O(1i) 3.014(5) Å, angle at H(80) 167°;
i (x, 1 + y, z). Consequently, the overall crystal packing
can be described as molecular, built up from {2(CHCl3)4}
repeating units.
comparable
with
the
data
reported
for
As mentioned above, the solid-state structures of 1:1
complexes involving all group-12 metals [MBr2(1)] [M = Zn
(4), Cd (5) and Hg (6)] were established by single-crystal X-
ray diffraction. Furthermore, an isomer of the latter com-
pound (denoted as 7, Scheme 3) was also structurally char-
acterised. Crystals of 7 suitable for diffraction analysis were
obtained from an attempted alkylation of 6 with iodome-
thane in methanol, followed by evaporation and crystallisa-
tion of the residue from acetone/diethyl ether. Although the
IR and solution NMR spectra of the bulk material are vir-
tually identical with the starting material 6, their crystal
structures differ markedly. Structural drawings for 4–7 are
shown below; selected structural parameters are listed in
the appropriate tables.
Clearly, the structures change with the metal and are dic-
tated by a subtle interplay between the hardness of the cen-
tral atom and the donor abilities of the functional groups
available at the ferrocene ligand. With zinc, the smallest and
hardest (though polarizable) metal in group 12, the ligand
Figure 4. A view of the molecular structure of complex 4 (molecule
1). Displacement ellipsoids enclose 30% probability. Atom labels
for molecule 2 (see text) are obtained by adding one to the first
coordinates through both donor groups to form a molecu- digit of the respective atom label in molecule 1.
Table 3. Selected bond lengths [Å] and angles [°] for 4.[a]
Molecule 1
Molecule 2
Zn(1)–Br(11)
Zn(1)–Br(12)
Zn(1)–P(12)
Zn(1)–O(11)
P(11)–O(11)
P(11)–O(12)
P(11)–O(13)
P(11)–C(101)
P(12)–C[b]
Angles at Zn(1)
Zn(1)–O(11)–P(11)
O–P(11)–O[d]
C–P(12)–C[f]
Fe(1)–Cg(11)
Fe(1)–Cg(21)
Є Cp(11),Cp(12)
τ(1)[h]
2.3602(5)
2.3401(5)
2.4097(8)
2.008(2)
1.479(2)
1.559(2)
1.577(2)
1.757(3)
1.794(3)–1.824(3)
101.44(6)–116.85(2)
144.0(1)
101.8(1)–116.4(1)
103.6(1)–106.8(1)
1.650(1)
1.647(1)
2.9(2)
53.0(2)
Zn(2)–Br(21)
Zn(2)–Br(22)
Zn(2)–P(22)
Zn(2)–O(21)
P(21)–O(21)
P(21)–O(22)
P(21)–O(23)
P(21)–C(201)
P(12)–C[c]
angles at Zn(2)
Zn(2)–O(21)–P(21)
O–P(21)–O[e]
C–P(22)–C[g]
Fe(2)–Cg(21)
Fe(2)–Cg(21)
Є Cp(21),Cp(22)
τ(2)[i]
2.3661(5)
2.3636(5)
2.4249(8)
2.004(2)
1.481(2)
1.551(2)
1.571(2)
1.747(3)
1.800(3)–1.825(3)
99.17(6)–115.73(2)
145.3(1)
101.5(1)–116.7(1)
104.5(1)–107.9(1)
1.645(2)
1.648(2)
1.8(2)
–60.2(2)
[a] Definitions of the ring planes: Cp(11) C(101–105), Cp(12) C(106–110), Cp(21) C(201–205), Cp(22) C(206–210). Cg(ij) denotes the
respective ring centroid. [b] The range of P(12)–C(106,C111,C117) bond lengths. [c] The range of P(22)–C(206,C211,C217) bond lengths.
[d] The range of O(11)–P(11)–O(12,13) and O(12)–P(11)–O(13) angles. [e] The range of O(21)–P(21)–O(22,23) and O(22)–P(21)–O(23)
angles. [f] The range of C(106)–P(12)–C(111,117) and C(111)–P(12)–C(117) angles. [g] The range of C(206)–P(22)–C(211,217) and C(211)–
P(22)–C(217) angles. [h] Torsion angle C(101)–Cg(11)–Cg(12)–C(106). [i] Torsion angle C(201)–Cg(21)–Cg(22)–C(206).
Eur. J. Inorg. Chem. 2006, 926–938
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
931

ˇ
P. S teˇpnicˇka, I. Císarˇová, R. Gyepes
FULL PAPER
[ZnCl2{FcP(O)(OEt)2-κO1}2] [Zn–O 1.978(4), P=O structural index parameter proposed by Addison et al.[27]
1.467(4), P–OEt 1.555(4) and 1.568(4), P–C 1.770(6) Å][10c] allows us to classify the donor set around the cadmium
and [ZnCl2(dippf-κ2P,PЈ)] (Zn–P av. 2.415 Å).[20b]
atoms as trigonal bipyramid rather than a square pyramid
The solid-state structure of cadmium complex 5 (Fig- (this parameter has a value of 0.76; the values for an ideal-
ure 5) is relatively complicated (Scheme 2, Table 4). For- ised trigonal bipyramid and square pyramid are 1 and 0,
mally, the “CdBr2” units associate into dimers through two respectively). It should be noted that pentacoordinate cad-
bromide bridges. In addition, each cadmium atom is coor- mium centres are relatively common, in line with the larger
dinated to two phosphanylphosphonate ligands (once atomic radius of the metal,[28] and has even precedents
through P=O and once through PPh2) and thus has a coor- among structurally characterised complexes featuring sim-
dination number of five. The dicadmium {Cd2Br4} units are ple[29a] and functionalised phosphanes.[29b,29c]
interconnected by means of symmetric ligand pairs to form
infinite one-dimensional ribbons (Scheme 2; see also Fig-
ure 6).
The molecular structure of mercury complex 6 seems, a
priori, to be different from 5 as it consists of dimeric
[{HgBr2(1-κP2)}2] units (Figure 7, Table 5) as commonly
observed for 1:1 phosphane–mercury() halide complexes.
However, a closer inspection of the crystal structure reveals
the structures to be very similar. The atoms within the cells
of both compounds are distributed in a similar manner (see
Figure 6), which brings the phosphoryl oxygen O(1) and
mercury atoms from neighbouring molecules into proximity
[Hg···O = 2.788(2) Å]. Thus, the O(1) atom is capping the
{Br(1),Br(2),P(2)} face of a severely distorted tetrahedral
donor array formed by phosphane and bromide ligands, al-
though somewhat asymmetrically with respect to the Hg–
Br(2i) axis (i: 1 – x, –y, 1 – z), being displaced towards the
Br(2)···P(2) edge. As a result, the primary donor set around
the mercury atom exhibits severe angular deformation. The
protrusion of an extra donor into the coordination sphere
of mercury leads to a considerable opening of the Br(2)–
Hg–P(2) and, mainly, Br(1)–Hg–P(2) angles (up to about
134° in the latter case), which is compensated by closure of
the Br(2)–Hg–Br(2i) and Br(2i)–Hg–P(2) angles. It should
be noted that in view of the asymmetric “[4+1]” donor envi-
ronment around the mercury atom, the bonding situation
can be described equally well as highly distorted trigonal
pyramidal.
The coordination sphere around the mercury atom in 6
is also asymmetric as far as the mercury–donor atom bond
lengths are concerned: the three different Hg–Br bond
lengths vary by as much as 0.45 Å. As expected, the bond
to the terminal bromide Hg–Br(1) is the shortest one while
the Hg–Br(2i) distance is the longest. This clearly points to
a competition between the O(1) and Br(2i) atoms for the
coordination site at the mercury.
The bonding situation in solid 7, yet another isomer of
the [HgBr2(1)] adduct, is more straightforward. The crystal
structure (Figure 8, Table 6) consists of discrete centrosym-
metric dimers where two phosphanylphosphonate ligands
span two HgBr2 units {i.e., 7 can be formulated as [(µ-
1κP2:2κO1-1)(µ-1κO1:2κP2-1)(HgBr)2]}. The coordination
sphere around the mercury centres departs slightly from a
Figure 5. A view of the dicadmium core in 5. Atomic radii corre-
spond to the isotropic displacement parameters (Uiso); symmetry
codes: i: 1 – x, 1 – y, –z; ii: 1 – x, 1 – y, 1 – z; iii: x, y, z – 1.
Table 4. Selected bond lengths [Å] and angles [°] for 5.[a]
Cd–Br(1)
Cd–Br(2)
Cd–Br(2i)
Cd–P(2ii)
Cd–O(1)
Cd···Cdi
P(1)–O(1)
P(1)–O(2)
P(1)–O(3)
P(1)–C(1)
P(2)–C[b]
2.5556(4)
2.6458(4)
2.8373(3)
2.6306(7)
2.394(2)
4.0737(3)
1.481(2)
1.571(2)
1.566(2)
1.771(3)
O(1)–Cd–Br(2i)
O(1)–Cd–Br(1)
O(1)–Cd–Br(2)
O(1)–Cd–P(2ii)
167.50(5)
94.82(5)
86.82(5)
87.60(5)
Br(2i)–Cd–Br(1) 97.05(1)
Br(2i)–Cd–Br(2) 84.10(1)
Br(2i)–Cd–P(2ii) 89.41(2)
Br(1)–Cd–Br(2) 118.44(1)
Br(1)–Cd–P(2ii)
Br(2)–Cd–P(2ii)
122.06(2)
119.50(2)
100.3(1)–115.0(1)
103.2(1)–104.5(1)
1.3(2)
1.804(2)–1.823(3) O–P(1)–O[c]
C–P(2)–C[d]
Fe–Cg(1)
Fe–Cg(2)
1.648(2)
1.643(2)
Є Cp(1),Cp(2)
τ(1)[e]
–155.9(2)
[a] Definitions of the ring planes: Cp(1) C(1–5), Cp(2) C(6–10);
Cg(i) denotes the respective ring centroid. Symmetry operations
used to generate equivalent positions: i: 1 – x, 1 – y, –z; ii: 1 – x,
1 – y, 1 – z. [b] The range of P(2)–C(6,11,17) bonds lengths. [c] The
range of O(1)–P(1)–O(2,3) and O(2)–P(1)–O(3) angles. [d] The
range of C(6)–P(2)–C(11,17) and C(11)–P(2)–C(17) angles. [e] Tor-
sion angle C(1)–Cg(1)–Cg(2)–C(6).
The dicadmium core in 5 (Figure 5) is centrosymmetric regular tetrahedron, most likely due to the presence of the
and its geometry is best described as two identical trigonal sterically encumbered phosphanylferrocene moiety and its
bipyramids sharing an edge connecting the axial and equa- orientation towards the {Hg,Br(1),Br(2)} plane: the P(2)–
torial positions. Because of the steric demands of the li- Hg–Br(1,2) angles are less acute, which, in turn, causes a
gands and the different cadmium–donor distances [Cd– closure of the O(2ii)–Hg–Br(1,2) and O(2ii)–Hg–P(1) angles
O(1i) Ͻ Cd–Br(1) Ͻ Cd–P(2ii) Ϸ Cd–Br(2) Ͻ Cd–Br(2i); (i: –x, 2 – y, –z). However, the deformation is much less
for symmetry codes, see Figure 5], the trigonal bipyramidal pronounced than in 6. The Hg–Br distances in 7 are very
arrangements are markedly distorted. Nonetheless, the similar and do not differ much from the remaining Hg–
932
www.eurjic.org
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2006, 926–938

Pd and Group-12 Metal Complexes with Hybrid Phosphanylphosphonate Ferrocene Ligand
FULL PAPER
Figure 6. Views of the individual polymeric chain in the structure of 5 (top) and a part of the linear assembly of the dimeric molecules
of 6 in the solid state, emphasising the similarity of both structures [intermolecular Hg···O contacts are indicated with arrows; symmetry
operations: A: 1 – x, –y, 1 – z; B: 1 – x, 1 – y, 1 – z; C: x, 1 + y, z]. Hydrogen atoms and solvate molecules have been omitted to avoid
complicating the figure.
Figure 7. A view of the molecular structure of complex 6 as determined for the solvate 6·5C6H6 (solvent molecules have been omitted
for clarity). The dimeric molecule is perfectly centrosymmetric due to the imposed symmetry: the halves lie across the crystallographic
inversion centre that coincides with the midpoint of the central {Hg2Br2} ring. Displacement ellipsoids are drawn with 30% probability.
Symmetry operations: i: 1 – x, –y, 1 – z.
donor bond lengths (compare with 6). Remarkably, the Hg– dination of the ligand moiety does not alter its structure in
O(1ii) distance in 7 is only about 5% shorter than that in any significant way. The P=O bond lengths are practically
6.[30]
identical in all compounds regardless of whether the phos-
A comparison of the structures determined for the free phonate group is free or bonded to a metal (the relative
and several forms of coordinated ligand 1 reveals that coor- elongation accompanying the coordination is typically less
Eur. J. Inorg. Chem. 2006, 926–938
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
933

ˇ
P. S teˇpnicˇka, I. Císarˇová, R. Gyepes
FULL PAPER
Table 5. Selected bond lengths [Å] and angles [°] for 6·5C6H6.[a]
than 1%). Likewise, the O–P–O angles at the phosphonate
group do not change upon coordination; in all the struc-
tures determined, the O(1)–P(1)–O(2,3) angles are about
10–15° less acute than the remaining angle O(2)–P(1)–O(3).
On the other hand, the coordination of the diphenylphos-
phanyl moiety leads to a slight opening of the C–P(2)–C
angles, which thus approach values closer to the tetrahedral
ones, albeit without influencing the P(2)–C bond lengths in
any significant manner.
More importantly, coordination causes conformational
changes to the ferrocene framework. In the free ligand as
well and in the complexes, where it acts as an O,P bridge in
a discrete dimer (7), a polymeric chain (5), and in a supra-
molecularly interacting assembly (6), the 1,1Ј-disubstituted
Hg–Br(1)
Hg–Br(2)
Hg–Br(2i)
Hg–P(2)
P(1)–O(1)
P(1)–O(2)
P(1)–O(3)
P(1)–C(1)
P(2)–C[c]
Fe–Cg(1)
Fe–Cg(2)
2.5362(5)
2.6523(4)
2.9858(4)
2.4342(9)
1.472(3)
1.578(3)
1.571(4)
1.776(4)
Br(1)–Hg–Br(2) 105.48(1)
Br(1)–Hg–Br(2i) 100.76(1)
Br(1)–Hg–P(2)
Br(2)–Hg–Br(2i) 83.85(1)
Br(2)–Hg–P(2) 118.95(3)
134.49(3)
Br(2i)–Hg–P(2) 93.59(2)
Hg–Br(2)–Hgi
O–P(1)–O[b]
96.15(1)
102.3(2)–115.3(2)
104.2(2)–106.1(2)
1.0(2)
1.791(4)–1.824(3) C–P(2)–C[d]
1.657(2)
1.654(2)
ЄCp(1),Cp(2)
τ(1)[e]
–155.9(2)
[a] Definitions of the ring planes: Cp(1) C(1–5), Cp(2) C(6–10);
Cg(i) denotes the respective ring centroid. Symmetry operation
used to generate equivalent positions: i: 1 – x, –y, 1 – z. [b] The
range of O(1)–P(1)–O(2,3) and O(2)–P(1)–O(3) angles. [c] The
range of P(2)–C(6,11,17) bonds lengths. [d] The range of C(6)– ferrocene unit adopts a conformation between syn-eclipsed
P(2)–(11,17) and C(11)–P(2)–C(17) angles. [e] Torsion angle C(1)–
(τ = 144°) and anti-staggered (τ = 180°), with the torsion
Cg(1)–Cg(2)–C(6).
angles falling in the very narrow range of 155–156°.[31] On
the other hand, the P2-monodentate ligands in hydrated 2
and 3·4CHCl3 have the donor groups rotated towards each
Table 6. Selected bond lengths [Å] and angles [°] for 7.[a]
other, as indicated by τ values of 103/92° (for ligand moie-
ties 1/2) and about 136°, respectively. Chelate coordination
Hg–Br(1) 2.5939(6)
Hg–Br(2) 2.5692(7)
Br(1)–Hg–Br(2) 110.10(2)
Br(1)–Hg–P(2) 127.60(3)
Br(1)–Hg–O(1i) 99.8(1)
Br(2)–Hg–P(2) 122.14(4)
Br(2)–Hg–O(1i) 89.06(9)
P(2)–Hg–O(1i) 86.4(1)
of 1 in the zinc() complex 4 brings the donor groups even
further into proximity, which is reflected by the τ values
of around 53° and 60° for molecules 1 and 2, respectively,
indicating an intermediate conformation between syn-stag-
gered (36°) and syn-eclipsed (72°) for the ferrocene unit.
Hg–P(2)
2.446(2)
Hg–O(1i) 2.638(4)
P(1)–O(1) 1.468(5)
P(1)–O(2) 1.574(5)
P(1)–O(3) 1.571(5)
P(1)–C(1) 1.777(5)
P(2)–C[d] 1.799(5)–1.813(6)
Fe–Cg(1) 1.654(3)
Fe–Cg(2) 1.645(3)
O–P(1)–O[b]
C–P(2)–C[c]
102.2(2)–115.6(2)
104.2(3)–106.0(3)
Conclusions
Є Cp(1),Cp(2) 0.3(3)
τ(1)[e]
155.2(5)
In summary, organometallic phosphanylphosphonate 1,
which is accessible in good yield by sequential metallation/
functionalisation of 1,1Ј-dibromoferrocene, is a typical ex-
ample of a hybrid ligand that is novel to ferrocene chemis-
try. In palladium() complexes it binds predominantly
through the phosphanyl group. However, the participation
[a] Definitions of the ring planes: Cp(1) C(1–5), Cp(2) C(6–10);
Cg(i) are the respective ring centroids. Symmetry operation used to
generate equivalent positions: i: –x, 2 – y, –z. [b] The range of O(1)–
P(1)–O(2,3) and O(2)–P(1)–O(3) angles. [c] The range of C(6)–
P(2)–(11,17) and C(11)–P(2)–C(17) angles. [d] The range of P(2)–
C(6,11,17) bonds lengths. [e] Torsion angle C(1)–Cg(1)–Cg(2)–C(6).
Figure 8. Molecular structure of compound 7. Similarly to 6, the parts of the dimeric structure are related by a crystallographic inversion
operation. Displacement ellipsoids are shown with 30% probability.
934
www.eurjic.org
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2006, 926–938

Pd and Group-12 Metal Complexes with Hybrid Phosphanylphosphonate Ferrocene Ligand
FULL PAPER
with diethyl chlorophosphate (0.9 mL, 6 mmol). The resulting yel-
low-brown solution was stirred for another 15 min at –80 °C and
then for 3 h at room temperature. The mixture was evaporated un-
der reduced pressure and the resulting orange-brown oil (contain-
ing precipitated LiCl) was purified by column chromatography on
alumina with chloroform/diethyl ether (2:3) as the eluent. The first
fraction containing mostly (diphenylphosphanyl)ferrocene was dis-
carded and the second, major band was collected and carefully
evaporated under vacuum to give 1 as a viscous, amber oil, which
crystallised upon standing at +4 °C. Yield: 2.185 g (86%). 1H
in coordination of the hard phosphonate group can be trig-
gered by increasing the hardness of the ligated metal. This
is exemplified by the crystal structures of group-12 metal
complexes 4–7, where the increasing hardness of the metal
cation results in an increase of the role of O1 Ǟ M dative
bonding. The hybrid nature of 1 is reflected also by the
behaviour of “[HgBr2(1)]” in solution: the presence of a
weakly coordinating group (phosphonate) renders this ad-
duct structurally fluxional and also allows for isolation of
isomeric complexes (6 and 7).
It should be pointed out that the direct structural (crys-
tallographic) data discussed in this paper represent the most
complete series available thus far for a single phosphanyl-
phosphonate ligand.[32] The data not only demonstrate the
flexible nature of 1 as a ligand in the individual molecules
of the complexes but also its potential to act as a building
block in supramolecular coordination structures. Further
investigations into the coordination properties of 1 aimed
at new structural motifs are currently underway.
3
NMR (CDCl3): δ = 1.30 (t, JH,H = 7.1 Hz, 6 H, CH3), 4.03–4.14
(m, 4 H, OCH2), 4.21 (vt, 2 H), 4.26 (d of vt, 2 H), 4.39 (vq, 2 H),
4.58 (vt, 2 H) (fc), 7.29–7.38 (m, 10 H, PPh2) ppm. 13C{1H} NMR
3
2
(CDCl3): δ = 16.44 (d, JP,C = 7 Hz, CH3), 61.73 (d, JP,C = 6 Hz,
OCH2), 67.59 (d, JP,C = 215 Hz, CPV of fc), 72.29 (d, JP,C
=
1
15 Hz), 72.92 (dd, JP,C = 14 and 1 Hz), 73.39 (d, JP,C = 4 Hz), 74.26
(d, JP,C = 14 Hz) (4×CH of fc), 77.70 (d, 1JP,C = 8 Hz, CPIII of fc),
128.19 (d, JP,C = 7 Hz), 128.62, 133.44 (d, JP,C = 20 Hz) (3×CH of
PPh2), 138.60 (d, 1JP,C = 10 Hz, Cipso of PPh2) ppm. 31P{1H} NMR
(CDCl3): δ = –17.0 (PIII), +25.7 (PV) ppm. IR (neat): ν = 3069 (m),
˜
3052 (m), 2981 (s), 2903 (m) ν(C–H); 1478 (s), 1434 (s), 1389 (s),
1369 (m), 1249 (vs), 1188 (s), 1162 (m), 1096 (m), 1050 (vs), 1030
(vs), 961 (vs), 831 (s), 794 (m), 746 (s), 699 (s), 595 (s), 492 (s), 454
(m) cm–1. EI MS: m/z (%) = 507 (25), 506 (100) [M+·], 449 (5) [M –
C4H9]+ or [M – C2H5 – C2H4]+, 321 (12) (possibly [FeC5H4POPh2]+;
see ref.[33]), 226 (6), 225 (18), 201 (19), 198 (6), 197 (5), 183 (35),
171 (16), 170 (10), 141 (5), 133 (8), 121 (14), 119 (13), 56 (5).
HRMS calcd. for C26H2856FeO3P2: 506.0863; found 506.0860.
Preparation of trans-[{Pd(µ-Cl)Cl(1-κP2)}2] (2): Solid [PdCl2(cod)]
(57 mg, 0.20 mmol) and 1 (107 mg, 0.21 mmol) were mixed with
methanol (3 mL). The solids quickly dissolved to give a burgundy-
red solution. The mixture was stirred at room temperature for
90 min and then allowed to stand at –18 °C for several days. The
separated microcrystalline solid was filtered off, washed with di-
ethyl ether and dried under vacuum. Yield: 105 mg (76%) of dark
red-brown solid (the product typically contains traces of 2 detect-
able in the 31P NMR spectrum). A crystal selected directly from
the reaction mixture (prior to the isolation) was shown to be the
Experimental Section
Materials and Methods: The synthesis of 1 was carried out under
argon using tetrahydrofuran (THF) freshly distilled from potas-
sium-benzophenone ketyl. The complexes were synthesised in ar-
gon-flushed vessels with exclusion of direct daylight. Chloroform
and benzene were dried with anhydrous potassium carbonate and
potassium, respectively. Acetone was dried with phosphorus pent-
oxide, distilled, and stored over activated molecular sieves (4 Å). 1-
Bromo-1Ј-(diphenylphosphanyl)ferrocene was prepared from 1,1Ј-
dibromoferrocene as reported in the literature.[7a] Other chemicals
(Lachema, Fluka) and solvents used for crystallisations (methanol,
diethyl ether and hexane; Lachema) were used as received.
NMR spectra were recorded with a Varian Unity Inova spectrome-
ter (1H: 399.95; 13C: 100.58; 31P: 161.90 MHz) at 25 °C (unless
noted otherwise). Chemical shifts (δ, ppm) are given relative to in-
1
3
solvate 2·½H2O. H NMR (CDCl3): δ = 1.33 (t, JH,H = 7.1 Hz, 6
H, CH3), 4.07–4.20 (m, 4 H, OCH2), 4.70 (vq, 2 H), 4.76 (vq, 4
H), 4.81 (vq, 2 H), 5.27 (br. s, 2 H) (fc), 7.34–7.65 (m, 10 H, PPh2)
1
ternal tetramethylsilane (13C and H) or to external 85% aqueous
H3PO4 (31P). The phosphorus-substituted cyclopentadienyl rings
1
represent AAЈBBЈX spin systems (A, B = H, X = 31P), which give
ppm. 13C{1H} NMR (CDCl3): δ = 16.49 (d, JP,C = 6 Hz, CH3),
3
rise to characteristic non-binomial multiplets in the 1H NMR spec-
tra. Hence, the multiplicity of the signals of these magnetically non-
equivalent protons is given as virtual triplet (vt) or virtual quartet
(vq). A similar notation is used for virtual triplets occurring in
the 13C{1H} NMR spectrum of 3. Note: the JЈ values given below
2
1
62.03 (d, JP,C = 6 Hz, OCH2), 68.96 (very br. d, JP,C Ϸ 210 Hz,
CPV of fc), 70.22 (d, JP,C = 67 Hz, CPIII of fc), 73.59 (d, JP,C
=
1
15 Hz), 74.35 (d, JP,C = 9 Hz), 75.89 (d, JP,C = 13 Hz), approx.
76.97 (d, JP,C Ϸ 10 Hz, CH of fc; partly obscured by the solvent
1
signal), 128.23 (d, JP,C = 6 Hz, CH of PPh2), 128.34 (d, JP,C
=
(n)
(n+2)
represent an average of the
J
P,C
and
J
P,C
coupling constants
61 Hz, Cipso of PPh2), 134.69 (d, JP,C = 2 Hz), 133.70 (d, JP,C
=
in the ABX spin system 12C-31P(A)-(metal)-31P(B)-13C(X).[16] IR
spectra were measured with an FT IR Nicolet Magna 650 (all com-
pounds in the range 4000–400 cm–1, the complexes also in the far-
IR region: 600–100 cm–1). Positive-ion electron impact (EI) and
fast atom bombardment (FAB) mass spectra were measured with
a ZAB SEQ spectrometer. Electrospray (ESI) mass spectra were
recorded with a Bruker Esquire 3000 spectrometer; the samples
were dissolved in methanol or firstly in a little chloroform and then
diluted with a large excess of methanol.
12 Hz, CH of PPh2) ppm. 31P{1H} NMR (CDCl3): δ = +24.6 (PV),
+31.1 ppm (PIII) (tentative assignment). IR (Nujol): ν = 1246 (m),
˜
1184 (m), 1166 (m), 1100 (m), 1027 (vs), 969 (m), 956 (m), 842 (w),
753 (m), 692 (m), 594 (m), 545 (m), 522 (m), 480 (s) cm–1. Far-IR
(polyethene): ν = 356 (s), 350 (sh), 258 (s), 147 (m), 229 (w), 155 (w)
˜
cm–1. ESI MS: m/z = 933, 647 [Pd(1)Cl]+. C52H56Cl4Fe2O6P4Pd2
(1367.3): calcd. C 45.68, H 4.13; found C 45.24, H 4.17.
Preparation of trans-[PdCl2(1-κP2)2] (3): Neat
1
(112 mg,
0.22 mmol) was added to a suspension of [PdCl2(cod)] (29 mg,
0.10 mmol) in chloroform (4 mL). The yellow complex quickly dis-
solved to give a red solution, which was allowed to stand for 30 min
at room temperature and was then layered with hexane (ca. 10 mL)
and allowed to crystallise at 0 °C for several days to afford 2 as an
orange, crystalline solid. The complex forms solvates with varying
chloroform content: the crystals isolated directly from the mother
Diethyl [1Ј-(Diphenylphosphanyl)ferrocenyl]phosphonate (1): Butyl-
lithium (2.4 mL 2.5  in hexanes, 6 mmol) was slowly added to a
stirred solution of 1-bromo-1Ј-(diphenylphosphanyl)ferrocene
(2.25 g, 5.0 mmol) in THF (50 mL) at –80 °C (temperature in bath).
The mixture, which darkened somewhat during the addition, was
stirred for another 30 min at the same temperature and then treated
Eur. J. Inorg. Chem. 2006, 926–938
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
935

ˇ
P. S teˇpnicˇka, I. Císarˇová, R. Gyepes
FULL PAPER
liquor and immediately analysed by X-ray diffractions were shown
to be the solvate 3·4CHCl3. The main portion of the crystalline
product, which was isolated by filtration, washed with a little hex-
ane and dried in air, was characterised as 3·3CHCl3 (114 mg, 74%;
orange crystals). 1H NMR (CDCl3): δ = 1.30 (td, 3JH,H = 7.1, 4JP,H
was stirred at room temperature. The solids dissolved quickly to
give a clear, orange solution, which immediately deposited a yellow
precipitate. After stirring for 30 min, the mixture was transferred
to a freezer and allowed to stand at –18 °C overnight. The sepa-
rated solid was filtered off, washed with diethyl ether (3×2 mL)
= 0.5 Hz, 6 H, CH3), 4.02–4.15 (m, 4 H, OCH2), 4.58 (vq, 2 H), and dried under vacuum. Yield of 6: 75 mg (87%) of a yellow,
4.66 (s, 4 H), 4.89 (d of vt, 2 H) (fc), 7.34–7.62 (m, 10 H, PPh2) powdery solid. A similar reaction in benzene as the solvent (3 mL)
3
ppm. 13C{1H} NMR (CDCl3): δ = 16.45 (d, JP,C = 7 Hz, CH3), gave the microcrystalline solvate 6·5C6H6, which quickly decom-
2
1
61.85 (d, JP,C = 6 Hz, OCH2), 68.33 (d, JP,C = 214 Hz, CPV of poses in air by losing solvent. Crystals suitable for X-ray measure-
fc), 72.83 (vt, JЈ = 27 Hz, CPIII of fc), 72.95 (d, JP,C = 15 Hz, CH ments were taken directly from the reaction and covered with
of C5H4PV), 74.35 (vt, JЈ = 4 Hz, CH of C5H4PIII), 74.92 (d, JP,C
paraffin oil to prevent their decomposition. The selected specimen
= 13 Hz, CH of C5H4PV), 76.70 (m, CH of C5H4PIII; obscured by was fixed onto a glass fibre with wax and transferred to the dif-
the solvent signal), 127.84 (vt, JЈ = 5 Hz), 130.43 (2×CH of PPh2), fractometer (see also X-ray crystallography below). 1H NMR
3
130.90 (vt, JЈ = 25 Hz, Cipso of PPh2), 134.11 (vt, JЈ = 6 Hz, CH (CDCl3): δ = 1.29 (t, JH,H = 7.1 Hz, 6 H, CH3), 4.00–4.14 (m, 4
of PPh2) ppm. 31P{1H} NMR (CDCl3): δ = +15.3 (PIII), +25.1 (PV) H, OCH2), 4.47 (vq, 2 H), 4.69 (d of vt, 2 H), 4.77 (br. vq, 2 H),
ppm. IR (Nujol): ν = 1248 (s), 1179 (s), 1169 (s), 1096 (m), 1056 4.86 (br. vt, 2 H) (fc), 7.52–7.79 (m, 10 H, PPh2) ppm. 13C{1H}
˜
3
2
(s), 1030 (vs), 965 (vs), 836 (m), 797 (m), 745 (s), 692 (m), 592 (m), NMR (CDCl3): δ = 16.42 (d, JP,C = 7 Hz, CH3), 62.05 (d, JP,C
=
504 (s) cm–1. Far-IR (polyethene): ν = 354 (m), 189 (w) cm–1.
6 Hz, OCH2), 68.11 (d, JP,C = 60 Hz, CPIII of fc), 69.11 (d, JP,C
1
1
˜
ESI MS: m/z = 1211/1213 [M + Na]+, 1153/1155 [M – Cl]+,
= 60 Hz, CPV of fc), 73.34 (d, JP,C = 15 Hz), 74.30 (d, JP,C = 13 Hz),
1119/1121 [Pd(1)
+
H]+, 861 [Pd(1)2
–
FeC5H4PO3Et2]+. 75.08 (d, JP,C = 13 Hz), 75.94 (d, JP,C = 9 Hz) (CH of fc), 127.71
1
C52H56Cl2Fe2O6P4Pd·3CHCl3 (1654.5): calcd. C 42.67, H 3.84; (d, JP,C = 54 Hz, Cipso of PPh2), 129.55 (d, JP,C = 12 Hz, CH of
found C 42.71, H 3.82.
PPh2), 132.46 (d, JP,C = 3 Hz), 133.53 (d, JP,C = 13 Hz) (CH of
PPh2) ppm. 31P{1H} NMR (CDCl3): δ = 24.3 (s with 199Hg satel-
Preparation of [ZnBr2(1-κ2O1,P2)] (4): Phosphonate 1 (58 mg,
0.11 mmol) and anhydrous zinc() bromide (23 mg, 0.10 mmol)
were dissolved in acetone (2 mL). The resulting orange solution
was stirred for one day and then allowed to crystallise by diffusion
of diethyl ether vapour. Well-developed orange crystals of the prod-
uct, which formed during several days, were filtered off, washed
with hexane and dried under reduced pressure. Yield: 52 mg (71%).
1
3
lites, JHg,P = 6610 Hz, PIII), +23.9 (d, JP,P = 5 Hz, PV). Note:
the spectra change with the sample concentration (see Table 1). IR
(Nujol): ν = 1225 (s), 1185 (m), 1099 (m), 1065 (m), 1051 (m), 1019
˜
(s), 977 (w), 963 (m), 845 (m), 750 (m), 694 (m), 596 (m), 518 (w),
498 (s), 845 (w), 468 (w) cm–1. Far IR (polyethene): ν = 343 (w),
˜
316 (w), 264 (w), 254 (m), ν(HgBr) 182 (sh), 176 (s) cm–1. ESI MS:
m/z = 787 [Hg(1)Br]+, 529 [1 + Na]+. C26H28Br2FeHgO3P2
(866.70): calcd. C 36.03, H 3.26; found C 35.95, H 3.24.
1H NMR (CDCl3): δ = 1.41 (td, JH,H = 7.0, JP,H = 0.7 Hz, 6 H,
3
4
CH3), 4.26–4.37 (m, 4 H, OCH2 and CH of fc), 4.45 (ddq, J = 7.8,
3
Attempted Alkylation of 6. Isolation of 7: Neat methyl iodide
(0.31 mL, 5 mmol) was added to a solution of 6 prepared in situ
by stirring HgBr2 (36 mg, 0.10 mmol) and 1 (57 mg, 0.11 mmol) in
methanol (2 mL) for 15 min. The mixture was stirred for 1 h at
room temperature, allowed to stand at 0 °C overnight, and then
evaporated under vacuum. The oily residue was dissolved in ace-
tone (ca. 2 mL) and crystallised by gas-phase diffusion of diethyl
ether over several days. The crystalline solid formed was filtered
off, washed with diethyl ether and dried under vacuum to give 7 as
an orange microcrystalline solid. Yield: 81 mg (93%). IR and solu-
tion NMR spectra of 7 are identical to those of 6.
9.9 Hz, JH,H = 7.0 Hz, 2 H, OCH2), 4.56 (vq, 2 H), 4.65 (d of vt,
2 H), 4.79 (vq, 2 H) (fc), 7.39–7.71 (m, 10 H, PPh2) ppm. 13C{1H}
3
1
NMR (CDCl3): δ = 16.19 (d, JP,C = 7 Hz, CH3), 64.46 (d, JP,C
=
223 Hz, CPV of fc), 64.61 (d, JP,C = 6 Hz, OCH2), 69.19 (d, JP,C
= 42 Hz, CPIII of fc), 72.83 (d, JP,C = 15 Hz), 73.37 (d, JP,C = 7 Hz),
73.62 (d, JP,C = 16 Hz), 75.52 (d, JP,C = 11 Hz) (CH of fc), 128.88
2
1
1
(d, JP,C = 7 Hz, CH of PPh2), 129.37 (d, JP,C = 38 Hz, Cipso of
PPh2), 131.06 (d, JP,C = 2 Hz), 133.74 (d, JP,C = 13 Hz) (CH of
PPh2) ppm. 31P{1H} NMR (CDCl3): δ = –19.9 (d, JP,P = 5 Hz,
3
PIII), +26.1 (d, 3JP,P = 5 Hz, PV). IR (Nujol): ν = 1212 (s), 1177 (s),
˜
1100 (m), 1027 (vs), 983 (w), 966 (w), 845 (w), 828 (m), 813 (m),
754 (m), 743 (m), 694 (m), 592 (s), 489 (s), 466 (s) cm–1. Far-IR
X-ray Crystallography: Crystals suitable for single-crystal X-ray dif-
fraction analysis were selected directly from the reaction batch [1:
(polyethene): ν = 356 (m), 317 (m), 317 (m), 2351 (s), 244 (s), 219
˜
(s) cm–1. ESI MS: m/z = 651 [Zn(1)Br]+, 529 [1 + Na]+.
C26H28Br2FeO3P2Zn (731.50): calcd. C 42.69, H 3.86; found C
42.68, H 3.76.
orange
plate,
0.08×0.25×0.50 mm;
4:
orange
prism,
0.30×0.33×0.45 mm; 5: orange block, 0.15×0.20×0.20 mm,
6·5C6H6: fragment of a yellow plate, 0.08×0.08×0.28 mm (see
preparation of this compound above), 7: orange prism,
0.05×0.08×0.08 mm] or grown by recrystallisation from chloro-
form/hexane (2·4CHCl3: orange plate, 0.10×0.30×0.43 mm). Full-
set diffraction data (θ Յ 27.5°) were collected on a Nonius Kap-
paCCD diffractometer equipped with a Cryostream Cooler (Ox-
ford Cryosystems) using graphite-monochromated Mo-Kα radia-
tion (λ = 0.71073 Å) and analysed with the HKL program pack-
age.[34] The data were corrected for absorption by using the routines
incorporated in the diffractometer software (1, 4, 5, and 6·5C6H6:
Gaussian correction after indexation of the crystal faces;
2·4CHCl3: numerical correction from the indexed crystal shape;
7: numerical correction based on multiply measured diffractions);
transmission factor ranges are given in Table 7. The structures were
solved by direct methods (SIR97[35]) and refined by a weighted full-
matrix least-squares procedure on F2 (SHELXL97[36]). All non-hy-
drogen atoms were refined with anisotropic thermal motion param-
Preparation of [CdBr2(1-κ2O,P2)] (5): Phosphonate 1 (56 mg,
0.11 mmol) and CdBr2·4H2O (35 mg, 0.10 mmol) were suspended
in a mixture of acetone (2 mL) and methanol (1 mL), and the reac-
tion mixture was stirred for 1 d. The solids quickly dissolved to
give a clear, orange solution. Crystallisation and isolation as above
afforded 5 as an orange, crystalline solid (64 mg, 82%). IR (Nujol):
ν = 1212 (vs), 1178 (vs), 1095 (m), 1067 (m), 1047 (m), 1022 (vs),
˜
982 (m), 964 (m), 837 (w), 795 (w), 751 (s), 697 (s), 591 (s), 498 (s),
486 (m), 458 (w), 442 (w) cm–1. Far-IR (polyethene): ν = 367 (m),
˜
336 (m), 321 (m), 266 (m), 254 (m), 214 (w), 193 (s), 158 (s), 116
(m) cm–1. ESI MS: m/z = 699 [Cd(1)Br]+, 529 [1 + Na]+.
C26H28CdBr2FeO3P2 (778.52): calcd. C 40.11, H 3.63; found C
40.04, H 3.62.
Reaction of HgBr2 with 1 to Form 6: A mixture of phosphonate 1
(57 mg, 0.11 mmol), HgBr2 (36 mg, 0.10 mmol) and acetone (2 mL)
936
www.eurjic.org
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2006, 926–938

Pd and Group-12 Metal Complexes with Hybrid Phosphanylphosphonate Ferrocene Ligand
Table 7. Crystallographic data and data-collection and structure-refinement parameters for 2·4CHCl3, and 4–7.[a]
FULL PAPER
Compound
1
2·4CHCl3
4
5
6·5C6H6
7
[b]
Formula
C26H28FeO3P2 C56H60Cl14Fe2O6P4Pd[a] C26H28Br2FeO3P2Zn C26H28CdBr2FeO3P2 C82H86Br4Fe2Hg2O6P4 C52H56Br4Fe2Hg2O6P4
M [gmol–1
]
506.27
1667.32
triclinic
P1 (no. 2)
9.2420(2)
9.6900(1)
20.6309(4)
98.613(1)
90.8192(9)
109.896(1)
1
731.46
778.49
2123.91
triclinic
P1 (no. 2)
11.3805(3)
13.1881(2)
14.8156(4)
87.526(2)
73.830(1)
68.706(1)
1
1733.37
triclinic
P1 (no. 2)
11.4381(2)
11.4585(2)
12.1543(2)
88.924(1)
83.964(1)
61.7160(8)
1
Crystal system
Space group
a [Å]
b [Å]
c [Å]
α [°]
β [°]
γ [°]
triclinic
orthorhombic
Pca21 (no. 29)[c]
19.1144(2)
17.1194(1)
17.5230(2)
triclinic
¯
¯
¯
¯
¯
P1 (no. 2)
P1 (no. 2)
8.4620(2)
12.4184(2)
12.7060(2)
74.290(1)
72.094(1)
77.3483(9)
2
11.2372(2)
11.4026(3)
13.0812(3)
70.580(1)
78.680(1)
61.164(1)
2
Z
V [Å3]
8
1209.56(4)
1.390
1713.49(5)
1.616
5734.00(9)
1.695
1383.46(5)
1.869
1985.68(8)
1.776
1394.14(4)
2.065
Dcalcd. [g mL–1
T [K]
]
150(2)
150(2)
150(2)
150(2)
150(2)
150(2)
µ(Mo-Kα) [mm–1
T[d]
]
0.781
1.363
4.267
1.323
6.356
9.027
0.747–0.930
35528
0.670–0.859
29888
0.227–0.387
97688
0.367–0.613
24724
0.273–0.664
31669
0.379–0.539
48178
Reflns. total
Rint [%][e]
3.93
4.24
5.11
4.05
5.43
7.95
Unique/obsd.[f] reflns. 5556/4944
7818/6733
4.08
13125/11869
2.67
6346/5734
2.55
9106/7962
3.00
6395/5095
3.59
R (obsd. data) [%][g]
R, wR (all data)[%][g] 4.11, 9.89
∆ρ [eÅ–3
1.05, –0.98
3.55
5.01, 10.3
1.46, –0.54
3.47, 5.27
1.34, –0.99
3.03, 6.19
1.12, –0.94
3.85, 714
0.98, –2.03
5.56, 8.36
1.37, –1.74
]
[a] (C52H56Cl2Fe2O6P4Pd)(CHCl3)4. [b] (C26H28Br2FeHgO3P2)2(C6H6)5. [c] Flack’s enantiomorph parameter: –0.007(4). [d] The range of
transmission coefficients. [e] Rint = Σ|Fo2 Ϫ Fo2(mean)|/ΣFo2, where Fo2(mean) is the average intensity for symmetry-equivalent reflections.
[f] Diffractions with Io Ͼ 2σ(Io). [g] R = Σ||Fo| – |Fc||/Σ|Fo|, wR = [Σ{w(Fo – Fc ) }/Σw(Fo2)2]1/2
.
2
2 2
[6]
[7]
a) M. Laly, R. Broussier, B. Gautheron, Tetrahedron Lett. 2000,
41, 1183; b) J.-C. Hierso, F. Lacassin, R. Broussier, R. Amard-
eil, P. Meunier, J. Organomet. Chem. 2004, 689, 766.
a) I. R. Butler, R. L. Davies, Synthesis 1996, 1350; b) V. V. Gru-
shin, Organometallics 2001, 20, 3950; c) T. S. A. Hor, H. S. O.
Chan, K. L. Tan, L. T. Phang, Y. K. Yan, L. K. Liu, Y. S. Wen,
Polyhedron 1991, 10, 2437; d) L. T. Phang, K. S. Gan, H. K.
Lee, T. S. A. Hor, J. Chem. Soc., Dalton Trans. 1993, 2697; e)
G. Pilloni, B. Longato, G. Bandoli, Inorg. Chim. Acta 1998,
277, 163; f) R. J. Coyle, Yu. L. Slovokhotov, M. Yu. Antipin,
V. V. Grushin, V. Vladimir, Polyhedron 1998, 17, 3059.
a) G. Pilloni, B. Longato, G. Bandoli, Inorg. Chim. Acta 1998,
277, 163; b) R. Broussier, E. Bentabet, M. Laly, P. Richard,
L. G. Kuzmina, P. Serp, N. Wheatley, P. Kalck, B. Gautheron,
J. Organomet. Chem. 2000, 613, 77.
eters whilst the hydrogen atoms were included in the calculated
positions and refined using the riding model. Relevant crystallo-
graphic data are given in Table 7. Geometric parameters and struc-
tural drawing were produced with a recent version of the Platon
program.[37]
CCDC-281044 (for 1), -281045 (for 2·½H2O), -281046 (for
3·4CHCl3), -281047 (for 4), -281048 (for 5), -281049 (for 6·5C6H6),
and -281050 (for 7) contain the supplementary crystallographic
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.
[8]
Supporting Information (see footnote on the first page of this arti-
cle): The Supporting Information contains VT 1H and 31P{1H }
NMR spectra for 6 (Figures S1 and S2).
a) T. S. A. Hor in ref.[1a], chapter 1, p. 3; b) G. Bandoli, A.
Dolmela, Coord. Chem. Rev. 2000, 209, 161.
[9]
[10]
a) T. L. Schull, D. A. Knight, Coord. Chem. Rev. 2005, 249,
1269; b) S. R. Alley, W. Henderson, J. Organomet. Chem. 2001,
637–639, 216 and references cited therein; c) O. Oms, F. Mau-
rel, F. Carré, J. Le Bideau, A. Vioux, D. Leclercq, J. Or-
ganomet. Chem. 2004, 689, 2654.
Acknowledgments
This work was financially supported by the Grant Agency of the
Czech Republic (grant no. 104/05/0192).
[11]
[12]
S. Basra, J. G. de Vries, D. J. Hyett, G. Harrison, K. M. Heslop,
A. G. Orpen, P. G. Pringle, K. von der Luehe, Dalton Trans.
2004, 1901.
Crystallographic data for 3: C52H56Cl4Fe2O6P4Pd2·½H2O (sol-
[1] a) Ferrocenes: Homogeneous Catalysis, Organic Synthesis Mate-
rials Science (Eds.: A. Togni, T. Hayashi); VCH, Weinheim,
1995; b) A. Togni, in Metallocenes: Synthesis, Reactivity, Appli-
cations (Eds.: A. Togni, R. L. Halterman), Wiley-VCH,
Weinheim, 1998; vol. 2, chapter 11, p. 685; c) T. J. Colacot,
Chem. Rev. 2003, 103, 3101.
[2] R. C. J. Atkinson, V. C. Gibson, N. J. Long, Chem. Soc. Rev.
2004, 33, 313.
[3] I. R. Butler, W. R. Cullen, T. J. Kim, S. J. Rettig, J. Trotter, Or-
ganometallics 1985, 4, 972.
[4] I. R. Butler, S. J. Coles, M. B. Hursthouse, D. J. Roberts, N.
Fujimoto, Inorg. Chem. Commun. 2003, 6, 760.
[5] a) M. Yamashita, J. V. C. Vicario, J. F. Hartwig, J. Am. Chem.
Soc. 2003, 125, 16347; b) T. Tu, W.-P. Deng, X.-L. Hou, L.-X.
Dai, X.-C. Dong, Chem. Eur. J. 2003, 9, 3073.
¯
vating water), triclinic, space group P1 (no. 2), a = 9.8080(3),
b = 16.6990(7), c = 17.2320(8) Å; α = 93.588(2)°, β =
105.485(3)°, γ = 95.326(3)°; V = 2696.9(2) Å3, Z = 2, µ(Mo-
Kα) = 1.550 mm–1 (Gaussian absorption correction applied, T
range: 0.744–0.940); 36531 total, 9465 unique and 6850 ob-
served [Io Ͼ 2σ(Io)] reflections, final R (observed data) =
5.07%; wR (all data) = 13.21%. Atoms in the disordered phos-
phonate group were refined over two positions (with idealised
distances) with isotropic thermal motion parameters. All other
heavy atoms were refined anisotropically; hydrogen atoms were
included in calculated positions and refined using the riding
model (SHELXL97).
[13]
CSD version 5.24 (November 2004) with updates of February
and May 2005.
Eur. J. Inorg. Chem. 2006, 926–938
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
937

ˇ
P. S teˇpnicˇka, I. Císarˇová, R. Gyepes
FULL PAPER
[14] A search for structural fragments {Pd(µ-X)X(P)}2, where X is
any halide, furnished 36 hits with R below 10%. Most of them
are planar molecules (mostly due to imposed symmetry) with
the dihedral angle, φ, equal or close to 0°. Only four structures
exhibit φ higher than 15°; refcode (φ, °): NEHVUR (16.2),
QAHNOC (29.2), QIVLEM (38.0 and 41.9, two independent
fragments), WAVPOY (16.2); φ is the dihedral angle subtended
by the {PdX2P} planes.
[29] The following structures of phosphane–halide complexes fea-
turing pentacoordinate cadmium() centres have been retrieved
from the Cambridge Crystallographic Database (version 5.26
of November 2004 with updates from February and May
2005). None of the above compounds is polymeric; a) N. A.
Bell, T. D. Dee, I. W. Nowell, Inorg. Chim. Acta 1982, 65, L87
(code: BIYDIW); b) L. W. Houk, P. K. S. Gupta, M. B. Hos-
sain, D. van der Helm, Acta Crystallogr., Sect. B 1982, 38, 91
(code: BAZMIY); c) J. T. Mague, J. L. Krinsky, Inorg. Chem.
2001, 40, 1962 (code: QIWBON).
[30] Notably, the mercury-to-oxygen distances in 6 and 7 fall be-
tween the sum of covalent (2.38 Å) and contact (4.02 Å) radii
(atomic radii were taken from the Platon program[37]). The flex-
ibility of HgǟO dative bonding can be accounted for by its
relative weakness because a variation of the Hg–O distance will
result in relatively low energy changes which can, in turn, be
compensated by other operating effects, such as steric factors
and crystal packing forces.
[15] The ∆δP values were calculated from shifts given in ref.[16] (the
complexes) and in: S. O. Grim, A. W. Yanowsky, S. A. Bruno,
W. J. Bailey, E. F. Davidoff, T. J. Marks, J. Chem. Eng. Data
1970, 15, 497 (the ligand).
[16] P. S. Pregosin, R. W. Kunz, in 31P and 13C NMR of Transition
Metal Phosphane Complexes, NMR Basic Principles and Pro-
gress (Eds.: P. Diehl, E. Fluck, R. Kosfeld), Springer, Berlin,
1979, vol. 16, ch. E, p. 65 and references cited therein.
ˇ
[17] P. Steˇpnicˇka, J. Podlaha, R. Gyepes, M. Polásˇek, J. Organomet.
Chem. 1998, 552, 293.
[18] Similar reactions with a 2:1 molar ratio gave no defined solid
products, possibly due to a higher solubility of the compounds
formed.
[31] See also the discussion of conformations adopted by the related
ligand 1Ј-(diphenylphosphanyl)ferrocenecarboxylic acid in the
ˇ
solid state: P. Steˇpnicˇka, Eur. J. Inorg. Chem. 2005, 3787.
[19] [MCl2(dppf-κP,PЈ)]: M (∆δP) = Zn (–4.5 ppm), Cd (8.1 ppm) [32] According to the CSD,[13] the only other structurally character-
and Hg (+36.0 ppm). Data from: B. Corrain, B. Longato, G.
Favero, D. Ajò, G. Pilloni, U. Russo, F. R. Kreissl, Inorg. Chim.
Acta 1989, 157, 259.
ised ligand is diethyl 2-(diphenylphosphanyl)phenylphos-
phonate whereas the complexes featuring this and some related
donors whose structures were determined are limited exclu-
sively to those with palladium() and platinum() and just a
few examples for each ligand. Representative examples for di-
ethyl 2-(diphenylphosphanyl)phenylphosphonate: a) D. D. El-
lis, G. Harrison, A. G. Orpen, H. Phetmung, P. G. Pringle, J. G.
de Vries, H. Oevering, J. Chem. Soc., Dalton Trans. 2000, 67
(ligand and Pt complex); for diethyl 2-(diphenylphosphanyl)-
ethylphosphonate: b) S. Ganguly, J. T. Mague, D. M.
Roundhill, Inorg. Chem. 1992, 31, 3500 (Pd complex); for di-
ethyl 3-(diphenylphosphanyl)propylphosphonate: c) G. Guer-
rero, P. H. Mutin, F. Dahan, A. Vioux, J. Organomet. Chem.
2002, 649, 113 (Pd and Pt complexes).
[20] [MCl2(dippf-κP,PЈ)]: M (∆δP) = Zn (–6.6 ppm), Cd (+9.8 ppm)
and Hg (+40.3 ppm). The shifts were calculated from the data
cited in: a) A. R. Elsagir, F. Gassner, H. Görls, E. Dinjus, J.
Organomet. Chem. 2000, 597, 139; b) J. H. L. Ong, C. Nataro,
J. A. Golen, A. L. Rheingold, Organometallics 2003, 22, 5027.
[21] A. K. S. Chauhan, N. Singh, R. D. Srivastava, Appl. Or-
ganomet. Chem. 2003, 17, 586 and references cited therein.
[22] R. G. Goel, W. P. Henry, N. K. Jha, Inorg. Chem. 1982, 21,
2551.
[23] G. A. Bowmaker, J. J. Clase, N. W. Alcock, J. M. Kessler, J. H.
Nelson, J. S. Frye, Inorg. Chim. Acta 1993, 210, 107.
[24] R. J. Coyle, Y. L. Slovokhotov, M. Y. Antipitin, V. V. Grushin,
Polyhedron 1998, 17, 3059.
ˇ
[33] M. Polásˇek, P. Steˇpnicˇka, J. Mass Spectrom. 1998, 33, 739.
[34] Z. Otwinowski, W. Minor, HKL Denzo and Scalepack Program
Package, Nonius BV, Delft, The Netherlands. For a reference,
see: Z. Otwinowski, W. Minor, Methods Enzymol. 1997, 276,
307.
[25] V. C. Gibson, N. J. Long, A. J. P. White, C. K. Williams, J.
Chem. Soc., Dalton Trans. 2002, 3280.
ˇ
[26] D. Drahonˇovský, I. Císarˇová, P. Steˇpnicˇka, D. Dvorˇáková, P.
Malonˇ, D. Dvorˇák, Collect. Czech. Chem. Commun. 2001, 66,
[35] A. Altomare, M. C. Burla, M. Camalli, G. L. Cascarano, C.
Giacovazzo, A. Guagliardi, A. G. G. Moliterni, G. Polidori, R.
Spagna, J. Appl. Crystallogr. 1999, 32, 115.
[36] G. M. Sheldrick, SHELXL97. Program for Crystal Structure
Refinement from Diffraction Data, University of Göttingen,
Germany, 1997.
[37] A. L.Spek, Platon, a multipurpose crystallographic tool, Utrecht
University, Utrecht, The Netherlands, 2003 and updates. Dis-
tributed via Internet; home page: http://www.cryst.chem.uu.nl/
platon/.
588.
[27] A. W. Addison, T. N. Rao, J. Reedijk, J. van Rijn, G. C. Ver-
schoor, J. Chem. Soc., Dalton Trans. 1984, 1349.
[28] The ionic radii for divalent metals with coordination number
of six are 0.88 (Zn), 1.09 (Cd) and 1.16 Å (Hg). Besides, cad-
mium(), like any other metal ion with a d10 configuration, has
no preferred coordination geometry due to ligand-field stabili-
sation. Consequently, the coordination geometries are deter-
mined chiefly by interplay of electrostatic forces, the nature of
the ligands and steric factors. For a reference see, for example:
F. A. Cotton, G. Wilkinson, C. A. Murillo, M. Bochmann, Ad-
vanced Inorganic Chemistry, 6th ed., Wiley, New York, 1999,
chapter 15, p. 598 ff.
Received: August 15, 2005
Published Online: January 16, 2006
938
www.eurjic.org
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2006, 926–938