Synthesis and structural characterization of rac-2-[(diphenylphosphino)methyl]ferrocenecarboxylic acid, its selected derivatives and some rhodium complexes

Article abstract of DOI:10.1016/j.jorganchem.2005.06.035

rac-2-[(Diphenylphosphino)methyl]ferrocenecarboxylic acid (1) was prepared in a good yield from rac-2-(N,N-dimethylaminomethyl)bromoferrocene (2) via rac-2-(hydroxymethyl)bromoferrocene (4) and rac-2-[(diphenylphosphino)methyl]bromoferrocene (5), and further converted to the respective phosphine oxide (6), phosphine sulfide (7) and methyl ester (8). The phosphines 1 and 8 were studied as ligands in rhodium complexes. The reaction of di-μ-chloro-bis[chloro-(η ⁵-pentamethylcyclopentadienyl)rhodium(III)] with the stoichiometric amounts of 1 and 8 yielded the corresponding mononuclear complexes with P-monodentate ligands: [RhC₂(η⁵-C₅Me ₅)(L-κP)], 9 and 10, respectively. Attempted deprotonation of 9 with LiBu or KOt-Bu gave intractable mixtures, in which the parent complex 9 as the major component was accompanied by two new compounds, likely the diastereoizomeric phosphinocarboxylate complexes. A defined O,P-chelating phosphinocarboxylate complex, [SP-4-2]-carbonyl-[rac-2-{(diphenylphosphino)methyl} ferrocenecarboxylato-κ²O,P]-tricyclohexylphosphinerhodium(I) (12), was obtained from the displacement of acetylacetonate(1-) (acac) ligand in [Rh(acac)(CO)(PCy₃)] (Cy = cyclohexyl) with acid 1. The structures of 1, 6 ? CHCl₃, and 7 ? 1/2 CH ₂Cl₂, 10, and hydrated complexes 9 and 12 were determined by single-crystal X-ray diffraction.

Full text of DOI:10.1016/j.jorganchem.2005.06.035

Journal of Organometallic Chemistry 690 (2005) 4285–4301
www.elsevier.com/locate/jorganchem
Synthesis and structural characterization
of rac-2-[(diphenylphosphino)methyl]ferrocenecarboxylic acid,
its selected derivatives and some rhodium complexes
ˇ
*
´ ˇ
´
ˇ
ˇ
Martin Lamacˇ, Ivana Cısarova, Petr Stepnicka
Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 40 Prague, Czech Republic
Received 4 January 2005; received in revised form 2 June 2005; accepted 2 June 2005
Available online 11 August 2005
Abstract
rac-2-[(Diphenylphosphino)methyl]ferrocenecarboxylic acid (1) was prepared in a good yield from rac-2-(N,N-dimethylaminom-
ethyl)bromoferrocene (2) via rac-2-(hydroxymethyl)bromoferrocene (4) and rac-2-[(diphenylphosphino)methyl]bromoferrocene (5),
and further converted to the respective phosphine oxide (6), phosphine sulfide (7) and methyl ester (8). The phosphines 1 and 8 were
studied as ligands in rhodium complexes. The reaction of di-l-chloro-bis[chloro-(g5-pentamethylcyclopentadienyl)rhodium(III)]
with the stoichiometric amounts of 1 and 8 yielded the corresponding mononuclear complexes with P-monodentate ligands:
[RhCl2(g5-C5Me5)(L-jP)], 9 and 10, respectively. Attempted deprotonation of 9 with LiBu or KOt-Bu gave intractable mixtures,
in which the parent complex 9 as the major component was accompanied by two new compounds, likely the diastereoizomeric
phosphinocarboxylate complexes. A defined O,P-chelating phosphinocarboxylate complex, [SP-4-2]-carbonyl-[rac-2-{(diphenyl-
phosphino)methyl}ferrocenecarboxylato-j2O,P]-tricyclohexylphosphinerhodium(I) (12), was obtained from the displacement of
acetylacetonate(1ꢀ) (acac) ligand in [Rh(acac)(CO)(PCy3)] (Cy = cyclohexyl) with acid 1. The structures of 1, 6 Æ CHCl3, and
7 Æ 1/2CH2Cl2, 10, and hydrated complexes 9 and 12 were determined by single-crystal X-ray diffraction.
ꢀ 2005 Elsevier B.V. All rights reserved.
Keywords: Hybrid ligands; Phosphines; Phosphinocarboxylic acids; Ferrocene; Rhodium; Crystal structure
1. Introduction
[5], the respective carboxylate can bind transition metals
as an O,O0-donor [6] or O,P-chelate [7]. Moreover, the
acid and the respective methyl ester have been tested
successfully as ligands in palladium-catalyzed Suzuki
cross-coupling [8], and the acid was utilized as a modifier
to MCM-41 with an aim of preparing supported cata-
lysts [9].
More recently, we [10] and others [11] prepared the
planarly chiral isomer of Hdpf, (Sp)-2-(diphenylphosph-
ino)ferrocenecarboxylic acid (A in Chart 1), and used
this chiral carboxyphosphine as a ligand in coordination
compounds [10] and as a precursor for the synthesis of
chiral ligands to be used in enantioselective catalysis
[11a,11b,12]. As a continuation of our work on ferrocene
carboxyphosphines, we turned to a formal homologue of
In spite of recent developments in the chemistry of
phosphinoferrocene ligands [1], there is still only little
known about ferrocene phosphines modified with polar
functional groups [2]. In 1996, we reported the syn-
thesis of 10-(diphenylphosphino)ferrocenecarboxylic
acid (Hdpf; see Chart 1) [3] – the first organometallic
compound falling into the class of hybrid phosphino-
carboxylic ligands [4]. Later studies revealed that
whereas Hdpf coordinates usually as a simple phosphine
*
Corresponding author. Fax: +420 221 951 253.
ˇ
E-mail address: stepnic@natur.cuni.cz (P. Steˇpnicˇka).
0022-328X/$ - see front matter ꢀ 2005 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2005.06.035

4286
M. Lamacˇ et al. / Journal of Organometallic Chemistry 690 (2005) 4285–4301
PPh
CO H
O
2
2
NMe
O
PPh
2
2
Fe
Fe
Me
Ac2O
Br
Br
Fe
Fe
CO H
2
Hdpf
A
3
2
CO H
PPh
2
CO H
2
KOH/H2O
PPh
2
2
Fe
Fe
PPh2
OH
B
1
i. Me3SiCl/NaI
ii. HPPh2
Br
Br
Fe
Fe
Chart 1.
5
4*
the latter compound, rac-[2-(diphenylphosphino)ferr-
ocenyl]acetic acid (B) [13]. A rather unique donor flexi-
bility of ligand B and the corresponding methyl ester
was demonstrated in a series of palladium(II) complexes,
where the compounds behaved as P-monodentate phos-
phines, O,P-chelating ligands (B in the form of carboxyl-
ate) [13,14] and, after deprotonation of the ester at the
activated methylene group, also as a C,P-chelating donor
[15].
Considering the promising results obtained with com-
pound B, we decided to prepare and study its isomer,
rac-2-[(diphenylphosphino)methyl]ferrocenecarboxylic
acid (1). In this contribution, we report on the synthesis
and structural characterization of this ferrocene phosph-
inocarboxylic acid, its selected derivatives, and their
rhodium complexes.
i. LiBu
ii. CO2 , then H
+
E
PPh2
PPh2
CO2H
H2O2 or S
CO2H
Fe
Fe
6 *(E = O)
7* (E = S)
1*
CH2N2
PPh2
CO2Me
Fe
8
2. Results and discussion
Scheme 1. Synthesis of carboxyphosphine 1 and the derivatives (the
asterisk indicates that the solid state structure has been determined).
2.1. Preparation and characterization of rac-[2-
(diphenylphosphino)methyl]ferrocenecarboxylic acid and
the derivatives
The subsequent preparation of phosphine bromide 5
proved rather difficult since neither bromoamine 2 nor
the oxygen derivatives 3 and 4 reacted with diphenyl-
phosphine to give the respective phosphinylated com-
pound 5 under the reaction conditions described for
the related 1-ferrocenylethyl derivatives [19]. It should
be noted that in an early attempt at the preparation of
1, we tried to replace similarly dimethylamino group in
rac-2-[(dimethylamino)methyl]ferrocenecarboxylic acid
with diphenylphosphine. However, the aminoacid,
which itself was difficult to synthesize and purify due
to its amphoteric nature (30% yield was obtained by
using the procedure described for the synthesis of rac-
The preparation of the target ligand, rac-2-[(diph-
enylphosphino)methyl]ferrocenecarboxylic acid (1), is
outlined in Scheme 1. The synthesis started from rac-
2-(N,N-dimethylaminomethyl)bromoferrocene (2), which
is accessible in a good yield from (N,N-dimethylami-
nomethyl)ferrocene by ortho-metallation and bromina-
tion with 1,2-dibromo-tetrafluoroethane as reported in
the literature [16]. Bromoamine 2 was then converted
by heating in acetic anhydride to acetate 3 and the ace-
tate hydrolyzed to alcohol 4. The alcohol was obtained
also directly by alkaline hydrolysis of the reaction mix-
ture resulting from the acetylation reaction. This one-
pot procedure proved more practical and better yielding
(85% vs. 75% for the two-step procedure). Compounds 3
[17] and 4 [18,17] have been already reported in the lit-
erature, but were synthesized by different methods.
The solid-state structure of alcohol 4 is presented below.
2-[1-(dimethylamino)ethyl]ferrocenecarboxylic
acid
[20]), did not react with the phosphine either – even
upon heating to 100 ꢁC in glacial acetic acid.
Finally, the key intermediate 5 was obtained in an
excellent yield directly from 4 by reacting the alcohol
in acetonitrile with chlorotrimethylsilane/sodium iodide

M. Lamacˇ et al. / Journal of Organometallic Chemistry 690 (2005) 4285–4301
4287
and then with an excess of diphenylphosphine as it was
recently described for related compounds by Sebesta
gism between conjugation of the carboxyl group with
the ferrocene unit and hydrogen-bond formation in the
solid state involving the carboxyl groups (see discussion
of the crystal structures below). Accordingly, the fre-
quency observed for 1 (1661 cmꢀ1) is very similar to
Hdpf (1666 cmꢀ1, [3]), which has the carboxyl group at-
tached directly to the ferrocene backbone and forms
similar hydrogen bonded associates, and lower than
for the isomeric acid B (1712 + 1695 sh cmꢀ1 [13]),
where the direct ferrocene-carboxyl conjugation is dis-
rupted. The m(C@O) band shifts to higher energies with
increasing the electron withdrawing properties of the
phosphorus substituent [m(C@O): 1 < 7 < 6]; esterifica-
tion has a similar but more pronounced effect (8:
1704 cmꢀ1).
Electron-impact mass spectra of 1–8 show fragment
ions typical for ferrocene compounds, e.g., those result-
ing from Fe–cyclopentadienyl bond cleavage such as
[C5H5Fe]+ and Fe+ (for complete data, see Section 4).
In addition, there are observed fragments specific for
the individual compounds. Thus, acetate 3 fragments
via a (formal) loss of C6H5Br, giving ions at m/z 180,
which can be most likely formulated as [C5H5FeOAc]+ꢀ,
and further by the loss of cyclopentadienyl radical (!
m/z 115). A similar transfer of an oxygen group to iron
was observed also for the respective alcohol: the molec-
ular ion 4+ꢀ fragments by elimination of bromine atom
yielding fragment species at m/z 215, which further elim-
inate phenyl radical to give ions [C5H5FeOH]+ꢀ (m/z
138) and, subsequently, cyclopentadienyl to give
[FeOH]+ (m/z 73). The transfer of oxygen groups to iron
atom during electron impact-induced fragmentation is
not unprecedented in ferrocene chemistry. For instance,
ferrocenecarboxylic acid and its methyl ester fragment
to ions [C5H5FeOR]+ꢀ (R = H or Me) [24] and 10-(diphe-
nylphosphinoyl)ferrocenecarboxylic acid (HdpfO) pro-
duces [Ph2PC5H5FeOH]+ꢀ [25].
ˇ
[21]. As the last step, bromide 5 was lithiated with butyl
lithium and the lithio intermediate carboxylated with
carbon dioxide. A subsequent acidification gave the de-
sired phosphinocarboxylic acid 1 in 73% yield after puri-
fication by column chromatography.
Furthermore, acid 1 was converted by the standard
procedures to the corresponding phosphine oxide (6),
phosphine sulfide (7) and methyl ester (8). All com-
pounds were characterized by spectral methods, elemen-
tal analysis, and the structures of 1, 6 Æ CHCl3, and
7 Æ 1/2CH2Cl2 have been determined by single-crystal
X-ray diffraction (see below).
Compounds 1–8 are chiral, possessing an unsymmet-
rically 1,2-disubstituted ferrocene unit but were synthe-
sized in the racemic form. Nevertheless, the chirality is
reflected in the spectra. For instance, the presence of chi-
rality plane makes the methylene protons diastereotopic
and, hence, anisochronous. As a result, the methylene
groups give rise to pairs of doublets in 1H NMR spectra
2
with the typical JHH coupling constants of ca. 12–
15 Hz. For compounds 1 and 5–8, these doublets are
further split by an interaction with the directly bonded
phosphorus groups. However, the extent of this interac-
2
tion as reflected by the magnitude of the JPH coupling
constants changes with the properties of phosphorus
group and with the overall molecular geometry. For
the mentioned series, the 2JPH values change from virtu-
ally no detected coupling in 5 and 1.3–1.5 Hz in the
phosphines (1 and 8) to ca. 12–15 Hz for the compounds
possessing pentavalent phosphorus groups (6 and 7).
The nature of the phosphorus group influences mark-
edly also the 13C NMR spectra. Apart from characteris-
tic changes in the region of PPh2 resonances (d and JPC
values) [22], this concerns mainly the directly attached
methylene group. Upon oxidation of carboxyphosphine
1 to the corresponding phosphine oxide or sulfide, the
doublet due to the methylene group moves to lower field
Fragmentation of phosphine bromide 5 differs from
the above compounds, the major fragmentation path-
ways for 5 being eliminations of PhBr (! m/z 306) or
PPh2 fragment (! m/z 277/279; this species is observed
also in the spectrum of 3). The presence of the diph-
enylphosphino group is reflected mainly by the character-
istic peaks at m/z 183, attributable to 9-phosphofluorene
cations (formally [PPh2 ꢀ 2 H]+, [26]).
1
and the direct JPC constant increase from ca. 15 Hz
(phosphines) to 67 Hz (6) and 49 Hz (7). 31P NMR
chemical shifts within the series 1 + 5–8 follow the ex-
pected trend [cf. ꢀ10.1 (1 and 8), 32.2 (6), 42.4 (7)].
However, the magnitude of the low field shift associated
with oxidation of phosphines to PV-compounds is signif-
icantly lower than in the homologous series derived
Likewise, the mass spectrum of acid 1 shows ions
resulting from C–P bond breakage (m/z 243,
[M ꢀ PPh2]+; base peak) as well as the ꢀcomplementaryꢁ
ions at m/z 183, originating from PPh2 (see above). Be-
sides, ions 1+ꢀ decompose by a simultaneous elimination
of CO2 + C6H6 (! m/z 306). Decarboxylation of frag-
ment ions at m/z 243 very likely gives rise to ferro-
cenylmethylium cation, [FcCH2]+ (or its isomeric
form) at m/z 199.
from rac-2-[(diphenylphosphino)ferrocenyl]acetic acid
31
(B in Chart 1). Besides, the
P NMR shift observed
for 1 compares favourably with that of FcCH2PPh2
(ꢀ11.8, [23]).
IR spectra of the studied compounds are too complex
for an unambiguous complete interpretation, an excep-
tion being the characteristic strong m(C@O) bands in
the spectra of the carboxylic derivatives 1 and 6–8.
The fact that the acids (1, 6, 7) show the m(C@O) bands
at relatively low frequencies can be ascribed to a syner-
The corresponding phosphine oxide (6+ꢀ) fragments
by a loss of cyclopentadienyl radical to give ions at m/z

4288
M. Lamacˇ et al. / Journal of Organometallic Chemistry 690 (2005) 4285–4301
379. In addition, the molecular ion and the ions at m/z
379 decarboxylate to give fragments at m/z 400 and
335, respectively. Analogous fragmentation pathways
are the major fragmentation processes for phosphine sul-
fide 7. In addition, the sulfide fragments by elimination
of sulfur atom from the molecular ion, giving ions iso-
baric (and likely isostructural) with 1+ꢀ, which further
decompose as described above for the acid.
a
Similarly to the parent acid, the spectra of ester 8 are
dominated by ions at m/z 257, resulting from an elimina-
tion of the diphenylphosphino group, which in turn
gives rise to fragments at m/z 183. The ions at m/z 257
are homologues to the ions at m/z 243 observed in the
spectrum of the parent acid and apparently relate to
the ions at m/z 227/229 observed in the spectrum of 3.
b
2.2. The solid-state structures of 4, 1, 6 Æ CHCl3, and 7 Æ
1/2CH2Cl2
As mentioned above, the compounds studied are
racemic and crystallize to form racemic crystals with
the symmetry of centrosymmetric space groups. Among
the structurally characterized compounds, alcohol 4 is
an exception, crystallizing with two molecules in the
asymmetric unit (C2/c space group; two molecules with
(Sp) configuration were chosen arbitrarily for the refine-
ment). Geometric parameters for the independent mole-
cules (Fig. 1(a), Table 1) differ only very marginally, e.g.,
in tilt of the cyclopentadienyl (Cp) rings and in torsion
angles at C(Cp)–C(OH) bond, the latter specifying the
orientation of the flexible hydroxymethyl side arm to-
wards its parent cyclopentadienyl ring. Besides, the mol-
ecules differ in conformation of the ferrocene unit: the
cyclopentadienyl rings in molecules 1 and 2 are rotated
by ca. 3ꢁ and 36ꢁ, which indicates a near-to-eclipsed
and a perfectly staggered conformation, respectively.
Considering such minimum differences between the mol-
ecules, the increase in the number of symmetrically inde-
pendent molecules should be sought in intermolecular
association. The molecules associate predominantly by
means of O–Hꢁ ꢁ ꢁO interactions so that each hydroxyl
group acts as both the hydrogen bond donor and accep-
tor, forming infinite helical chains parallel to the crystal-
lographic b-axis (Fig. 1(b), Table 2). The individual
chains involve molecules with the same configuration
[(Rp) or (Sp)] and, consequently, the unit cell accommo-
dates two pairs of chains differing only by their polarity.
Fig. 1. (a) A view of the molecular structure of molecule 1 in the
structure of alcohol 3. Thermal motion ellipsoids enclose 30%
probability. The respective atom labels for molecule 2 are obtained
by adding 20 [except for Fe(2), Br(2), O(2) and H(92)]. (b) Crystal
packing of 3 as viewed along the crystallographic b-axis showing the
hydrogen bonds as dashed lines. Hydrogen atoms except those at OH
groups are omitted for clarity.
tures are shown in Figs. 2–4 and the relevant structural
data are listed in Table 3. The arrangement of the ferro-
cene units in the acids is quite regular: the iron-ring cen-
troid distances for both cyclopentadienyl ring differ by
less than 0.5% and the ring tilts are lower than 5ꢁ. Nota-
bly, acid 1 exhibits a significant torsion at the C(1)–C(2)
bond whereas its phosphinoyl and thiophosphoryl deriv-
atives bearing bulkier phosphorus groups show only
negligible such deformation. In all compounds, the rota-
tion of the carboxyl group from the least-squares plane
of the substituted cyclopentadienyl ring does not exceed
15ꢁ and the carboxyl group is oriented so that the C@O
bond points to the methylene arm.
˚
The Oꢁ ꢁ ꢁO separations of ca. 2.75 A compare favour-
ably with the values observed for rac-[2-(diph-
˚
enylphosphino)ferrocenyl]methanol (2.751(3) A, [27])
and are shorter than those in [10-(diphenylphosph-
˚
ino)ferrocenyl]methanol (2.835(4)–2.866(4) A, [28]).
Steric demands of the phosphorus group increasing in
the order 1 (lone pair) > 6 (O) > 7 (S) are reflected by an
opening of the C(2)–C(12)–P angle. In the same order,
the angle subtended by the P–C(12) bond and the Cp1
The molecular structures of the acids differ only at the
phosphorus substituent. Therefore, structural parame-
ters for 1 and the solvates 6 Æ CHCl3 and 7 Æ 1/2CH2Cl2
will be discussed jointly. Views of the molecular struc-

M. Lamacˇ et al. / Journal of Organometallic Chemistry 690 (2005) 4285–4301
4289
Table 1
a
˚
Selected distances and angles for 4 (in A and ꢁ)
Molecule 1
Molecule 2
Fe–Cg1
Fe–Cg2
\Cp1,Cp2
C(1)–C(11)
C(11)–O(1)
Br(1)–C(2)
1.636(1)
1.652(2)
2.0(2)
1.483(4)
1.436(3)
1.889(3)
Fe–Cg3
Fe–Cg4
\Cp3,Cp4
C(21)–C(31)
C(31)–O(2)
Br(2)–C(22)
1.639(1)
1.651(2)
0.9(2)
1.489(4)
1.439(3)
1.888(3)
C(1)–C(11)–O(1)
C(2)–C(1)–C(11)
C(2)–C(1)–C(11)–O(1)
C(11)–C(1)–C(2)–Br(1)
a
108.8(2)
C(21)–C(31)–O(2)
C(22)–C(21)–C(31)
C(22)–C(21)–C(31)–O(2)
C(31)–C(21)–C(22)–Br(2)
108.1(2)
127.6(2)
ꢀ98.2(3)
1.6(4)
127.8(2)
ꢀ94.7(3)
0.4(4)
Ring definition: Cp1 = C(1–5), Cp2 = C(6–10), Cp3 = C(21–25), Cp4 = C(26–30). Cg denotes the respective ring centroid.
Table 2
Hydrogen bond parameters for 4, 1, 6 Æ CHCl3, 7 Æ 1/2CH2Cl2 (in A and ꢁ)
a
˚
D–Hꢁ ꢁ ꢁA
D–Hꢁ ꢁ ꢁA
D–H
D–Hꢁ ꢁ ꢁA
Compound 4
O(1)–H(91)ꢁ ꢁ ꢁO(2i)
2.746(3)
2.751(3)
0.75(3)
0.71(3)
178(6)
176(3)
O(2)–H(92) Æ Æ O(1)
Compound 1
O(2)–H(90)ꢁ ꢁ ꢁO(1ii)
2.629(3)
0.88(6)
171(5)
Compound 6 Æ CHCl3
O(2)–H(90)ꢁ ꢁ ꢁO(1iii)
C(25)–H(25)ꢁ ꢁ ꢁO(3iv)
2.646(2)
2.976(2)
0.69(3)
0.98
176(3)
173
Compound 7 Æ 1/2CH2Cl2
O(2)–H(90)ꢁ ꢁ ꢁO(1v)
2.663(2)
0.85(4)
179(6)
a
Values involving hydrogen atoms in geometrically defined positions are given without esdꢁs. Symmetry operations: (i) 1/2 ꢀ x, y ꢀ 1/2, 1/2 ꢀ z;
(ii) 1 ꢀ x, 1 ꢀ y, 1 ꢀ z; (iii) 1 ꢀ x, ꢀy, ꢀz; (iv) 1 + x, y, z; (v) ꢀx, ꢀy, 1 ꢀ z.
plane becomes more acute [76.3(2)ꢁ, 70.6(1)ꢁ, 67.2(1)ꢁ;
N.B. only the angle between 0ꢁ and 90ꢁ is considered],
though with only a minor change of the conformation
at the C(2)–C(12) bond (see the C(1)–C(2)–C(12)–P tor-
sional angles in Table 3).
In crystal, the acids associate into centrosymmetric
hydrogen-bonded dimers connected by a pair of O–
Hꢁ ꢁ ꢁO@C hydrogen bonds (notation according to
the graph set theory: R22ð8Þ [29]). The Oꢁ ꢁ ꢁO distances
are virtually independent of the phosphorus group,
differing relatively by only ca. 1% in the whole series
(Table 2). Compounds 1, 6, and 7 thus parallel the
˚
behaviour of Hdpf (Oꢁ ꢁ ꢁO ca. 2.65 A for Hdpf [3]
and complexes featuring P-coordinated Hdpf [5]) and
˚
B (Oꢁ ꢁ ꢁO 2.646(2) A [13]), which form similar supra-
molecular aggregates. The phosphinoyl oxygen atom
in 6, which is not involved in this interaction, forms
additional hydrogen bonds to the solvating chloro-
form molecules: P@Oꢁ ꢁ ꢁHCCl3 (Fig. 5, Table 2),
which fix the solvent molecules in the structure. On
the other hand, the structure of solvate 7 Æ 1/2CH2Cl2
lacks similar interactions, very likely due to much
worse hydrogen-bond acceptor properties of the sulfur
atom. Consequently, the solvating dichloromethane
is bonded only loosely in hydrophobic channels
defined by the phenyl rings. The solid-state assemblies
of the acids are further supported by graphitic
pꢁ ꢁ ꢁp stacking of the phenyl rings and C–Hꢁ ꢁ ꢁp
interactions.
Fig. 2. A view of the molecular structure of acid 1. Thermal motion
ellipsoids are drawn at the 30% probability level.

4290
M. Lamacˇ et al. / Journal of Organometallic Chemistry 690 (2005) 4285–4301
Fig. 3. The molecular structure of 6 Æ CHCl3. For clarity, the solvate
molecule is omitted. Thermal motion ellipsoids are drawn at the 30%
probability level.
Fig. 4. A view of the molecular structure of 7 Æ 1/2CH2Cl2. Disordered
solvate molecule are omitted. Thermal motion ellipsoids correspond to
the 30% probability level.
2.3. Preparation and structures of (g5-pentamethyl-
cyclopentadienyl)rhodium(III) complexes
gands bind as monodentate phosphines (Scheme 2).
The complexes were characterized by IR and NMR
spectra and their structures corroborated by single-crys-
tal X-ray diffraction. Exclusive P-coordination of the li-
gands is best reflected by 31P NMR spectra, where the
ligand signals are shifted to lower fields (coordination
shifts: DP 45.2 (9), 45.1 (10)) and show characteristic
Cleavage of the chloro bridges in di-l-chloro-bis-
[chloro-(g5-pentamethylcyclopentadienyl)rhodium(III)]
with the stoichiometric amounts of acid 1 and methyl es-
ter 8 gave the corresponding (g5-cyclopentadienyl)rho-
dium(III) complexes [RhCl2(g5-C5Me5)(1-jP)] (9) and
[RhCl2(g5-C5Me5)(8-jP)] (10), where the ferrocene li-
1
coupling with 103Rh (I = 1/2, 100% abundance; JRhP
ca. 140 Hz). On the other hand, 13C NMR resonances
Table 3
a
˚
Selected distances and angles for 1, 6 Æ CHCl3, and 7 Æ 1/2CH2Cl2 (in A and ꢁ)
Parameter
1
6 Æ CHCl3
7 Æ 1/2CH2Cl2
E
Void
O(3)
S
Fe–Cg1
Fe–Cg2
1.644(2)
1.651(2)
0.1(2)
1.462(4)
1.233(4)
1.313(4)
1.502(5)
1.861(4)
1.828(4)
1.828(4)
1.6475(9)
1.656(1)
4.4(1)
1.644(1)
1.649(1)
2.7(2)
\Cp1,Cp2
C(1)–C(11)
C(11)–O(1)
C(11)–O(2)
C(2)–C(12)
P–C(12)
P–C(13)
P–C(19)
P@E
O(1)–C(11)–O(2)
C(2)–C(12)–P
C–P–Cb
C–P–Ec
C(1)–C(2)–C(12)–P
C(11)–C(1)–C(2)–C(12)
\COO,Cp1d
a
1.460(3)
1.232(2)
1.315(2)
1.498(3)
1.817(2)
1.807(2)
1.801(2)
1.493(1)
122.9(2)
110.6(1)
105.55(8)–107.05(9)
112.16(8)–112.63(8)
93.6(2)
1.459(3)
1.228(3)
1.322(3)
1.497(3)
1.828(2)
1.817(2)
1.816(3)
1.9588(9)
122.7(2)
112.4(2)
104.7(1)–106.0(1)
112.49(8)–114.33(8)
92.5(2)
–
123.1(3)
107.7(2)
98.6(2)–105.0(2)
87.6(4)
12.9(6)
5.4(4)
1.5(3)
12.9(2)
3.8(4)
9.3(3)
Definitions of the ring planes: Cp1 = C(1–5), Cp2 = C(6–10), Cg1 and Cg2 are the respective ring centroids.
The range of C(12)–P–C(13,19) and C(13)–P–C(19) angles.
The range of C(12,13,19)–P–E angles.
b
c
d
Dihedral angle of the Cp1 and carboxyl [C(11)O(1)O(2)] planes.

M. Lamacˇ et al. / Journal of Organometallic Chemistry 690 (2005) 4285–4301
4291
Fig. 5. A schematic drawing of the hydrogen bonded aggregates in the structure of 6 Æ CHCl3.
the diastereoisomers of the formed phosphinocarboxy-
late complex 11 (Scheme 2) [30]. Unfortunately, all
attempts to purify the reaction mixtures by crystalliza-
tion or chromatography were unsuccessful.
The molecular structures of 9 and 10 as determined
by X-ray crystallography are shown in Figs. 6 and 7,
respectively, while the pertinent geometric data are
summarized in Table 4. Complex 9 crystallized from
aqueous acetic acid as an ill-defined hydrate, having
the solvating molecules located in a space close to the
polar carboxyl groups (see Section 4).
CO2Y
Fe
Rh
Rh
Cl
1 or 8
Cl
Cl
P
Cl
Cl
Cl
Ph
Rh
Ph
9 (Y = H)
10 (Y = Me)
only for 9
The molecules of the complexes are very similar,
adopting the expected three-legged piano stool geome-
try. In both cases, the phosphinocarboxylic ligand is
coordinated only via the phosphino group and its phe-
nyl rings are orientated towards the pentamethylcyclo-
pentadienyl (Cp*) ring. The respective dihedral angles
are: Ph vs. Cp3 29.5(2)ꢁ and 29.4(2)ꢁ for 9, and
14.1(2)ꢁ and 39.1(2)ꢁ for 10 (see Table 4 for the defini-
tion of the ring planes). The ferrocene moieties are direc-
ted to the other side of the Cp*Rh unit and rotated with
respect to the Cp* plane (cf. dihedral angle Cp1 vs. Cp3:
50.3(2)ꢁ for 9 and 42.6(3)ꢁ for 10). The coordination
spheres around the rhodium(III) atoms in both com-
pounds show noticeable deformations: the Cg3–Rh–P
angles are by ca. 10ꢁ less acute than the Cg3–Rh–
Cl(1,2) angles. However, this deformation, which appar-
ently results from the steric demands of the phosphine
group, causes virtually no slanting to the [Cp*RhL3]
unit (cf. the dihedral angles subtended by the Cp3 and
[PCl(1)Cl(2)] planes of 4.3(1)ꢁ and 3.8(1)ꢁ, respectively).
As far as the geometry of the phosphinocarboxylic li-
gand is concerned, the coordination influences the
arrangement of the phosphine substituent only, leaving
the rest of the ligand molecule nearly intact. The ligands
are coordinated without any deformation to the ferro-
cene unit and torsion at the C(1)–C(2) bond (see data
in Table 4). Coordination of the diphenylphosphino
base, - HCl
Rh
Cl
Ph
P
O
Ph
O
Fe
+ isomer
11
Scheme 2. Preparation of (g5-cyclopentadienyl)rhodium(III) com-
plexes.
of the carboxylic carbons as well as carbonyl stretching
bands in IR spectra shift upon coordination only very
slightly, thus excluding any significant involvement of
the carboxyl moieties in coordination to the rhodium
centres.
Attempts to synthesize a phosphinocarboxylate com-
plex by deprotonation of 9 with bases such as KOtBu or
LiBu failed. According to NMR spectra (see Section 4),
the reaction mixtures contained the parent complex 9
(major) and two new compounds, likely attributable to

4292
M. Lamacˇ et al. / Journal of Organometallic Chemistry 690 (2005) 4285–4301
Table 4
a
˚
Selected distances and angles for 9 and 10 (in A and ꢁ)
Parameter
9 (hydrate)
10
Rh–Cl(1)
Rh–Cl(2)
Rh–P
Rh–Cg3
Cg3–Rh–Cl(1)
Cg3–Rh–Cl(2)
Cg3–Rh–P
Cl(1)–Rh–Cl(2)
P–Rh–Cl(1)
P–Rh–Cl(2)
Fe–Cg1
2.4038(9)
2.4125(9)
2.3326(8)
1.814(2)
122.51(5)
121.34(5)
132.62(5)
91.76(3)
89.44(3)
87.66(3)
1.640(2)
1.645(2)
2.7(2)
2.4070(7)
2.4060(8)
2.3159(7)
1.815(1)
121.34(5)
123.29(5)
132.22(4)
92.69(3)
90.89(2)
84.96(3)
1.644(1)
1.650(2)
1.6(2)
1.466(4)
1.210(3)
1.338(4)
1.446(4)
1.496(4)
1.824(3)–1.853(2)
123.9(3)
115.8(2)
Fe–Cg2
\Cp1,Cp2
C(1)–C(11)
C(11)–O(1)
C(11)–O(2)
O(2)–C(35)
C(2)–C(12)
P–Cb
O(1)–C(11)O(2)
C(2)C(12)–P
C–P–Cc
1.461(5)
1.221(5)
1.327(5)
1.498(5)
1.823(3)–1.849(3)
121.7(4)
115.8(2)
104.2(2)–105.6(1)
111.4(3)
103.1(1)–107.4(1)
ꢀ90.6(3)
ꢀ1.3(4)
C(1)–C(2)–C(12)–P
C(11)–C(1)–C(2)–C(12)
\Cp1,COOH
a
ꢀ6.9(5)
6.7(5)
16.3(3)
Definition of the ring planes: Cp1 = C(1–5), Cp2 = C(6–10),
Cp3 = C(25–29). Cg(1–3) stand for the respective ring centroids.
COOH is the carboxyl plane [C(11)O(1)O(2)]
Fig. 6. The molecular structure of 9 (the solvate molecules are not
shown). Thermal motion ellipsoids are drawn at the 30% probability
level.
b
The range of P–C(12,13,19) distances.
The range of C(12)–P–C(13,19) and C(13)–P–C(19) angles.
c
group results in tetrahedrally surrounded phosphorus
atoms, which in turn causes an opening of the C–P–C
angles, similarly to oxidation of 1–6 or 7 (compare data
in Tables 3 and 4). Correspondingly, the C(1)–C(2)–P
angles are more opened due to an increased bulk of
the ꢀgroupꢁ attached to the methylene spacer.
2.4. Preparation and structure of a rhodium(I)
phosphinocarboxylate complex 12
The reaction of carboxyphosphine 1 with the stoichi-
ometric amount of rhodium(I)-acetylacetonato (acac)
complex [Rh(acac)(PCy3)(CO)] (Hacac = pentan-2,4-
dione, Cy = cyclohexyl) proceeds with acid–base dis-
placement of the acac ligand and formation of a chelating
phosphinocarboxylate complex 12 (Scheme 3). Acid 1
Ph
Ph
P
1
O
O
O
C
Rh
- Hacac
Fe
CO
PCy
Rh
O
3
Cy P
CO
3
12
Scheme 3. Synthesis of the chelating phosphinocarboxylatecomplex 12.
Fig. 7. A view of the molecular structure of 10. Thermal motion
ellipsoids are drawn at the 30% probability level.

M. Lamacˇ et al. / Journal of Organometallic Chemistry 690 (2005) 4285–4301
4293
Fig. 8. The molecular structure of 12. The solvate molecules are omitted for clarity. Thermal motion ellipsoids correspond to 30% probability level.
Table 5
thus seemingly parallels the reactivity of (diph-
enylphosphino)acetic acid [31] and Hdpf [7]. The complex
a
˚
Selected distances and angles for solvated 12 (in A and ꢁ)
Rh–P(1)
Rh–P(2)
Rh–O(2)
Rh–C(25)
2.301(2)
2.346(2)
2.078(4)
1.793(7)
O(1)–Rh–C(25)
P(2)–Rh–C(25)
O(2)–Rh–P(1)
O(2)–Rh–P(2)
Rh–C(25)–O(3)
89.5(2)
91.4(2)
91.6(1)
87.4(1)
179.6(6)
was characterized by standard spectral methods and ele-
mental analysis. In 31P NMR spectra, complex 12 exhibits
a pair of double doublets at dP 32.8 (carboxylate) and 40.9
(PCy3) with the characteristic 1JRhP (ca. 130 Hz) and 2JPP
(322 Hz) coupling constants [32]. On the other hand,
deprotonation and coordination of the carboxyl group
is reflected by a low-shift of the 13C NMR signal due
the carboxyl group (dC 175.28) and, mainly, by a shift
of the m(C@O) band to lower energies (ca. 60 cmꢀ1).
Recrystallization of 12 from commercial methanol
gives hydrates with varying water content. This corre-
sponds with the solid-state structure of 12 Æ 0.7H2O,
which revealed that the water molecules are distributed
rather freely in the crystal (though in hydrogen bond
distances) in voids left between the bulky hydrophobic
complex molecules, which itself are packed at the dis-
tances of the van der Walls contacts without further sig-
nificant intermolecular contacts.
C(25)–O(3) 1.148(8)
Fe–Cg1
Fe–Cg2
1.639(3)
1.653(4)
\Cp1,Cp2
\Cp1,COO
\[Rh],Cp1
\[Rh],COO
O(1)–C(11)–O(2) 122.2(5)
C(2)–C(12)–P(1) 110.7(4)
2.9(5)
41.0(7)
86.5(3)
58.8(7)
C(1)–C(11) 1.494(8)
C(11)–O(1) 1.238(8)
C(11)–O(2) 1.282(7)
C(2)–C(12) 1.494(7)
P(1)–Cb
P(2)–Cc
a
Definitions of the ring planes: Cp1 = C(1–5), Cp2 = C(6–10),
COO = [O(1)O(2)C(11)], [Rh] = [RhP(1)P(2)O(2)C(25)]. Cg1 and Cg2
are the centroids for Cp1 and Cp2, respectively.
1.800(5)–1.832(7) C–P(1)–Cd
1.841(6)–1.848(6) C–P(2)–Ce
103.9(3)–106.1(3)
104.4(3)–110.9(2)
b
The range of P(1)–C(12,13,19).
The range of P(2)–C(31,41,51).
The range of C(12)–P(1)–C(13,19) and C(13)–P(1)–C(19).
The range of C(31)–P(2)–C(41,51) and C(41)–P(2)–C(51).
c
d
e
The molecular structure of 12 is shown in Fig. 8 and
the pertinent geometric data are given in Table 5. Coor-
dination sphere around rhodium is nearly perfectly pla-
nar, with the interligand angles deviating from 90ꢁ only
very slightly. The individual Rh-donor distances are
practically identical with the respective values in trans-
[Rh(dpf-jO,P)(PCy3)(CO)] (Rh–P(dpf) 2.335(1), Rh–P-
bonyl ligands are almost identical to those in the former
reference compound.
On going from 1 to 12, the ligand moiety undergoes a
substantial change at the diphenylphosphino group
attaining a geometry similar to 9 and 10 (see above),
while the Rh O bonding is reflected only by a slight
shortening of the C(11)–O(2) and elongation of the
C(1)–C(11) distances. However, the main difference
can be seen in the ligand conformation: chelate forma-
tion results in rotation of the carboxyl group from the
plane of the Cp1 ring by as much as ca. 41ꢁ (see Table
˚
(PCy3) 2.342(1), Rh–O2.071(2), and Rh–CO 1.793(3) A
[7]) and trans-[Rh(Ph2PCH2CO2-jO,P)(Ph2PCH2CO2-
H-jP)(CO)] (Rh–P(carboxylate) 2.302(2), Rh–P(acid)
˚
2.346(2), Rh–O 2.064(6), and Rh–CO 1.77(1) A [31a]).
Likewise, the overall arrangements of the PCy3 and car-

4294
M. Lamacˇ et al. / Journal of Organometallic Chemistry 690 (2005) 4285–4301
5 for plane definitions) and reorientation of the
CH2PPh2 side arm (cf. the dihedral angle C(1)–C(2)–
C(12)–P(1) of ꢀ79.3(7)ꢁ). Consequently, the ferrocene
unit is nearly perpendicular to the coordination plane.
Phosphorus–carbon bonds (ꢀPC3ꢁ units) of both phos-
phine ligands are practically eclipsed. The cyclohexyl
rings in PCy3 adopt chair conformation with the phos-
phorus atom attached in equatorial positions (cf. the
NMR spectra were recorded on a Varian Unity Inova
spectrometer (1H, 399.95; 13C, 100.58; 31P, 161.90 MHz)
at 25 ꢁC. Chemical shifts (d/ppm) are given relative to
internal tetramethylsilane (13C and 1H) or external
85% aqueous H3PO4 (31P). IR spectra in the range of
400–4000 cmꢀ1 were measured on an FT IR Nicolet
Magna 760 instrument in Nujol mulls. Mass spectra
were measured either on a GS-MS Finnigan MAT IN-
COS 50 (GC–MS, EI mode) or on a ZAB-SEQ VG
Analytical (direct inlet EI, high resolution EI and FAB
spectra) spectrometers. Melting points were determined
on a Kofler hot stage and are uncorrected.
˚
ring puckering parameters: C(31-26) Q = 0.574(7) A,
˚
u1 = 2.3(7)ꢁ; C(41-46) Q = 0.558(8) A, u1 = 180.0(8)ꢁ;
˚
C(51-56) Q = 0.559(7) A, u1 = 174.9(7)ꢁ [33]).
3. Conclusions
4.2. Preparation of rac-(2-bromoferrocenyl)methyl
acetate (3)
Phosphinocarboxylic acid 1, a new organometallic
hybrid ligand, can be obtained by a multistep procedure
in a good overall yield from the readily accessible amine
2 (56% over the three steps 2 ! 4 ! 5 ! 1, see Scheme
1). As shown for the case of rhodium complexes, the li-
gand can coordinate as a P-monodentate phosphine and
O,P-chelating phosphinocarboxylate. A comparison of
the structural data available for the ligand and its com-
plexes indicates favourable ligand geometry, requiring
no significant structural deformation upon coordination
in either form.
rac-2-(N,N-dimethylaminomethyl)bromoferrocene
(2; 0.65 g, 2.0 mmol) was dissolved in acetic anhydride
(15 mL) and the reaction flask was transferred into an
oil bath heated to 100 ꢁC. After stirring for 3 h, the mix-
ture was cooled in an ice bath and hydrolyzed by careful
addition of saturated aqueous Na2CO3 solution (15 mL;
caution: exothermic, copious CO2 evolution) and stir-
ring for another 2.5 h, whereupon the product separated
as an orange oil. The mixture was extracted with diethyl
ether (3 · 15 mL), the combined organic phases were
washed twice with saturated aqueous NaHCO3, dried
over MgSO4 and evaporated under reduced pressure.
The crude product was purified by column chromatog-
raphy on silica gel using diethyl ether–hexane mixture
(1:1) as the eluent to afford 3 as an orange oil, which
solidifies to a yellow-orange solid (0.566 g, 83%).
4. Experimental
4.1. Materials and methods
1
M.p. 51–52 ꢁC. H NMR (CDCl3): d 2.05 (s, 3H,
Unless noted otherwise, all manipulations were car-
ried out under argon atmosphere. rac-2-(N,N-dimethy-
laminomethyl)bromoferrocene (2) was prepared by
metalation/bromination of (N,N-dimethylaminom-
ethyl)ferrocene [34] as described in the literature [16].
Compounds [{(l-Cl)RhCl(g5-C5Me5)}2] [35] and [Rh-
(acac)(CO)(PCy)3] [31b] were synthesized by the literature
procedures. Acetic anhydride and chlorotrimethylsilane
were freshly distilled under argon. Other reagents were
used as received from commercial sources (Lachema,
Fluka, Aldrich).
OC(O)Me), 4.16 (apparent t, J ꢂ 2.6 Hz, 1H, C5H3),
4.20 (s, 5H, C5H5), 4.30 (m, 1H, C5H3), 4.49 (m, 1H,
2
C5H3), 4.96 (d, JHH = 12.2 Hz, 1H, CH2), 5.06 (d,
2JHH = 12.2 Hz, 1H, CH2). 13C{1H} NMR (CDCl3): d
20.91 (OC(O)C3), 61.34 (CH2), 67.15 (C5H3 CH), 68.41
(C5H3 CH), 70.98 (C5H3 CH), 71.16 (C5H5), 80.07
(C5H3 Cipso), 80.09 (C5H3 Cipso), 170.87 (OCOCH3).
NMR data correspond with the literature [17]. IR (Nu-
jol, cmꢀ1): 1745 sh, 1730 vs, 1259 sh, 1240 vs, 1226 sh,
1172 w, 1106 w, 1071 w, 1026 m, 1001 m, 945 m, 916
w, 841 w, 814 m, 643 vw, 607 w, 520 w, 492 m, 456 w.
GC–MS, m/z (relative abundance): 338 (29.5), 336
(31.8), 279 (2.2), 277 (3.0), 181 (10.3), 180 (100.0), 141
(7.0), 134 (20.4), 121 (28.3), 115 (10.6), 77 (6.5), 56
(13.7), 43 (10.2). HR MS: calcd. for C13H1356Fe79BrO2
336.9448, found 336.9439.
Diethyl ether and tetrahydrofuran (THF) were dried
by refluxing with potassium and benzophenone until
blue, and then distilled. Acetonitrile was dried with
˚
phosphorus pentoxide, distilled and stored over 4 A
molecular sieves. The dry solvent was once again dis-
tilled before use. Toluene was dried with sodium metal
and distilled. Dichloromethane and chloroform were
dried by standing over anhydrous potassium carbonate
and distilled. Butan-2-one was dried over phosphorus
pentoxide and distilled just prior to use. Solvents for
workup, crystallizations and chromatography were used
without purification.
4.3. Preparation of rac-2-(hydroxymethyl)bromo-
ferrocene (4)
To a methanol solution of acetate 3 (300 mg,
0.89 mmol in 25 mL) was added potassium hydroxide
(2 g, 36 mmol) dissolved in water (25 mL) and the mix-

M. Lamacˇ et al. / Journal of Organometallic Chemistry 690 (2005) 4285–4301
4295
ture was heated to reflux overnight. After cooling to
room temperature, the organic solvent was removed
by evaporation under vacuum, and the aqueous residue
extracted with diethyl ether (3 · 15 mL). The combined
extracts were washed with saturated aqueous sodium
chloride, dried over magnesium sulfate, and evaporated
to dryness. The crude product was purified by column
chromatography on silica gel, eluting with diethyl ether.
A subsequent evaporation yielded alcohol 4 as a yellow
orange solid. Yield: 242 mg, 92%.
tion mixture turned from orange to dark red and a fine
precipitate formed (NaCl). After stirring for 5 min,
diphenylphosphine (3.45 mL, 20 mmol) was added,
causing the colour of the mixture to change to yellow.
The mixture was stirred for 24 h and then quenched with
saturated aqueous NaCl solution (40 mL). The mixture
was diluted with diethyl ether (50 mL), the organic layer
separated, washed twice with saturated aqueous NaCl
solution, dried (MgSO4), and then pre-adsorbed on sil-
ica gel. The solid material was transferred onto a top
of a chromatographic column and eluted with hexane–
diethyl ether (20:1). Unreacted phosphine is eluted first
followed by a yellow band of the product, which was
collected and evaporated to give 5 as an orange oil,
which solidified at 4 ꢁC. Yield: 4.17 g (90%).
M.p. 72.5–73.5 ꢁC. 1H NMR (CDCl3): d 1.64 (bs, 1H,
OH), 4.14 (apparent t, J ꢂ 2.6 Hz, 1H, C5H3), 4.21 (s,
5H, C5H5), 4.26 (m, 1H, C5H3), 4.41 (d, 2JHH = 12.3 Hz,
1H, CH2), 4.47 (m, 1H, C5H3), 4.58 (d, 2JHH = 12.3 Hz,
1H, CH2). 13C{1H} NMR (CDCl3): d 59.76 (CH2), 66.55
(C5H3 CH), 66.98 (C5H3 CH), 70.62 (C5H3 CH), 70.91
(C5H5), 79.39 (C5H3 Cipso), 85.67 (C5H3 Cipso). Analyti-
cal data are in accord with those in [17,18]. IR (Nujol,
cmꢀ1): 3220 br s, 1313 m, 1252 m, 1169 w, 1104 w,
1071 w, 1031 w, 1003 s, 981 m, 947 w, 824 m, 760 br
w, 695 br w, 618 w, 529 m, 488 s, 443 m. GC–MS,
m/z (relative abundance): 296 (59.9), 294 (63.2), 215
(5.1), 141 (12.6), 138 (100.0), 121 (11.5), 94 (5.4), 77 (8.8),
73 (12.8), 56 (16.1). Analysis calcd. for C11H11BrFeO:
44.79% C, 3.76% H, found 44.71% C, 3.61% H.
1
M.p. 55–56 ꢁC. H NMR (CDCl3): d 3.20 (d, 1H,
2
2JHH = 14.2 Hz CH2), 3.30 (d, 1H, JHH = 14.2 Hz
CH2), 3.77 (m, 1H, C5H3), 3.94 (apparent t, J ꢂ 2.6 Hz,
1H, C5H3), 4.13 (s, 5H, C5H5), 4.36 (m, 1H, C5H3),
7.31–7.48 (m, 10H, PPh2). 13C{1H} NMR (CDCl3): d
1
28.54 (d, JPC = 16 Hz, CH2), 65.61 (C5H3 CH), 67.16
3
(d, JPC = 6 Hz, C5H3 CH), 69.38 (C5 H3 CH), 71.33
3
(C5H5), 80.51 (d, JPC = 3 Hz, C5H3 C–Br), 83.36 (d,
3
2JPC = 16 Hz, C5H3 C–CH2), 128.32 (d, JPC = 3 Hz,
3
PPh2 Cm), 128.39 (d, JPC = 4 Hz, PPh2 CHm), 128.41
(PPh2 CHp), 128.96 (PPh2 CHp), 132.35 (d,
2
4.4. Preparation of 4 directly from amine 2
2JPC = 18 Hz, PPh2 CHo), 133.46 (d, JPC = 20 Hz,
1
PPh2 CHo), 138.12, 138.47 (2· d, JPC = 15 Hz, PPh2
A solution of amine 2 (16.18 g, 50 mmol) in acetic
anhydride (60 mL) was heated to 100 ꢁC in an oil bath
for 3 h while stirring and then evaporated under reduced
pressure (ca. 0.5 Torr). The orange oily residue, which
slowly crystallized, was immediately dissolved in metha-
nol (50 mL) and an aqueous solution of KOH (17 g,
0.3 mol in 50 mL of water) was added. The mixture
was refluxed for 20 h, cooled to room temperature,
and evaporated under vacuum to remove methanol.
The heterogeneous aqueous residue was extracted with
diethyl ether (3 · 50 mL), the extracts were washed with
water and saturated aqueous NaCl solution, and dried
over MgSO4 overnight. The solvent was removed under
reduced pressure, the residue dissolved in hot ethyl ace-
tate and crystallized by addition of hexane and standing
at room temperature and then at ꢀ18 ꢁC. The separated
orange crystalline product was filtered off, washed with
hexane and dried in air. Evaporation of the mother li-
quor and crystallization as above gave a second crop
of the alcohol. Combined yield of 4: 12.56 g (85%).
Cipso). 31P{1H} NMR (CDCl3): d ꢀ13.7 (s). MS (direct
inlet), m/z (relative abundance): 465 (10.4), 464 (37.9),
463 (11.2), 462 (40.9), 306 (5.0), 280 (13.8), 279 (94.0),
278 (17.9), 277 (100.0), 197 (23.5), 183 (39.5), 141
(37.0), 121 (15.9), 115 (15.6), 56 (17.3). HR MS: calcd.
for C23H2056Fe79BrOP (phosphine oxide) 477.9785,
found 477.9791.
4.6. Synthesis of rac-2-[(diphenylphosphino)methyl]-
ferrocenecarboxylic acid (1)
A solution of phosphine 5 (3.61 g, 7.8 mmol) in THF
(60 mL) cooled to ꢀ78 ꢁC (ethanol/CO2) was treated
with butyl lithium (3.9 mL, 2.5 M in hexanes, 9.8 mmol).
After stirring for 1 h at ꢀ78 ꢁC, the reaction solution was
poured onto a large excess of finely crushed solid CO2
(ca. 50 g) and allowed to stand overnight at room tem-
perature. Then, the mixture was diluted with dichloro-
methane (20 mL), washed with saturated aqueous NaCl
solution (2· 30 mL). The organic phase was dried over
MgSO4 and evaporated under vacuum. The residue
was purified by chromatography on silica gel with dichlo-
romethane–methanol (10:1). Some [(diphenylphosphino)
methyl]ferrocene was eluted first (ca. 0.49 g, identified by
NMR spectroscopy [23]), followed by a second major
band of acid 1, which after evaporation afforded the acid
as an orange solid. Yield: 2.44 g (73%).
4.5. Preparation of rac-2-[(diphenylphosphino)methyl]-
bromoferrocene (5)
At room temperature, neat chlorotrimethylsilane
(3.15 mL, 25 mmol) was introduced to a mixture of alco-
hol 4 (2.95 g, 10 mmol), NaI (3.00 g, 20 mmol) and dry
acetonitrile (80 mL) with stirring, whereupon the reac-

4296
M. Lamacˇ et al. / Journal of Organometallic Chemistry 690 (2005) 4285–4301
M.p. 172–173 ꢁC. 1H NMR (CDCl3): d 3.34 (dd,
1JPC = 34 Hz, PPh2 CHipso), 131.17, 131.27 (2· d,
2
1
2JHH = 13.7 Hz, JPH ꢂ 1.3 Hz, 1H, CH2), 3.90 (d,
2JPC = 7 Hz, PPh2 CHo); 131.85 (d, JPC = 34 Hz,
2JHH = 13.7 Hz, 1H, CH2), 4.06 (m, 1H, C5H3), 4.18
(s, 5H, C5H5), 4.25 (apparent t, J ꢂ 2.6 Hz, 1H,
C5H3), 4.77 (m, 1H, C5H3), 7.29–7.48 (m, 10H, PPh2).
PPh2 CHipso), 131.89, 132.00 (2· d, JPC = 3 Hz, PPh2
4
CHp); 175.22 (CO2H), signal due to C(C5H3)–CO2H
was not found. 31P{1H} NMR (CDCl3): d 32.2 (s). IR
(Nujol, cmꢀ1): 1689 s, 1591 w, 1281 m, 1213 m, 1171
s, 1120 s, 1099 s, 1074 m, 1036 w, 1001 m, 818 m, 785
w, 741 s, 694 s, 525 m, 507 s, 434 w. MS (direct inlet),
m/z (relative abundance): 445 (29.8), 444 (100.0), 400
(4.9), 380 (18.9), 379 (81.8), 336 (10.5), 335 (46.2), 333
(11.9), 322 (14.4), 257 (7.3), 201 (11.9), 183 (7.4), 121
(14.0), 105 (51.1), 77 (24.8), 56 (15.5). HR MS: calcd.
for C24H2156FeO3P 444.05778, found 444.0595.
1
13C{1H} NMR (CDCl3): d 28.57 (d, JPC = 15 Hz,
3
CH2), 67.56 (d, JPC = 3 Hz, C5H3 C–CO2H), 70.00
(C5H3 CH), 70.77 (C5H3 CH), 70.85 (C5H5), 73.71 (d,
2
3JPC = 5 Hz, C5H3 CH), 87.92 (d, JPC = 16 Hz, C5H3
C–CH2), 128.23, 128.27 (2· PPh2 CHm), 128.34, 128.91
2
(2· PPh2 CHp); 132.29 (d, JPC = 18 Hz, PPh2 CHo),
2
133.66 (d, JPC = 20 Hz, PPh2 CHo), 138.22, 138.73
1
(2· d, JPC = 15 Hz, PPh2 CHipso); 178.67 (C2H).
31P{1H} NMR (CDCl3): d ꢀ10.1 (s). IR (Nujol,
cmꢀ1): 1661 s, 1409 w, 1347 w, 1306 sh, 1289 s, 1229
m, 1173 w, 1155 w, 1113 w, 1104 m, 1072 w, 1038 w,
997 w, 934 br w, 863 w, 843 w, 827 w, 815 w, 783 w,
763 w, 752 m, 741 s, 701 m, 691 m, 626 w, 559 w, 516
m, 506 m, 494 w, 483 m, 471 m. MS (direct inlet), m/z
(relative abundance): 429 (15.5), 428 (51.0), 306 (14.2),
257 (5.7), 244 (30.4), 243 (100.0), 199 (16.2), 186
(14.2), 183 (18.9), 121 (8.8), 108 (24.5), 105 (53.0), 57
(19.6). HR MS: calcd. for C24H2156FeO2P 428.0629,
found 428.0652. Analysis calcd. for C24H21FeO2P:
67.31% C, 4.94% H, found 66.79% C, 4.86% H.
4.8. Preparation of rac-2-[(diphenylthiophosphoryl)
methyl]ferrocenecarboxylic acid (7)
A solution of acid 1 (170 mg, 0.40 mmol) and sulfur
(14 mg, 0.44 mmol) in toluene (20 mL) was heated at re-
flux for 1 h. After cooling to room temperature, the
solution was evaporated to ca. 5 mL and allowed to
crystallize at ꢀ18 ꢁC overnight. The orange microcrys-
talline solid was filtered off and dried in air. Yield:
156 mg (85%).
1
M.p. dec. above 135 ꢁC. H NMR (CDCl3): d 3.59
2
2
(virtual t, JHH ꢂ JPH ꢂ 14.3 Hz, 1H, CH2), 4.19 (s,
4.7. Preparation of rac-2-[(diphenylphosphoryl)methyl]-
ferrocenecarboxylic acid (6)
5H, C5H5), 4.41 (apparent t, J = 2.7 Hz, 1H, C5H3),
2
2
4.69 (m, 1H, C5H3), 4.77 (dd, JHH ꢂ JPH ꢂ 12 Hz,
1H, CH2), 4.77 (m, 1H, C5H3), 7.16–7.98 (m, 10H,
In air, hydrogen peroxide (0.5 mL 30%, 4 mmol) was
added dropwise to a stirred solution of acid 1 (160 mg,
0.37 mmol) in acetone (15 mL) with cooling in an ice
bath. After the addition had been completed, the cooling
bath was removed and stirring was continued at room
temperature for 15 min (the conversion was complete
in this time according to TLC analysis). Then, acetone
was removed under reduced pressure, the residue diluted
with water (20 mL) and extracted with dichloromethane
(3 · 15 mL). Combined extracts were washed with satu-
rated aqueous NaCl solution (20 mL), dried shortly over
MgSO4, and evaporated under vacuum. The residue was
purified by column chromatography on silica gel eluting
with dichloromethane–methanol (10:1) to yield 6 as a
brown solid after evaporation. Yield: 84 mg (51%; a
considerable amount of a dark material remains ad-
sorbed at the top of the chromatographic column).
PPh2). 13C{1H} NMR (CDCl3):
d
34.78 (d,
3
1JPC = 49 Hz, CH2), 67.63 (d, JPC ꢂ 1 Hz, C5H3 C–
CO2H), 70.74 (C5H3 CH), 70.94 (C5H3 CH), 71.09
3
(C5H5), 74.66 (d, JPC ꢂ 2 Hz, C5H3 CH), 81.73 (d,
2JPC ꢂ 2 Hz, C5H3 C–CH2), 127.96, 128.55 (2· d,
3JPC = 12 Hz, PPh2 CHm); 128.61 (d, JPC = 81 Hz,
1
4
PPh2 Cipso), 131.27, 131.61 (2· d, JPC = 3 Hz, PPh2
2
CHp); 131.70, 131.80 (2· d, JPC = 6 Hz, PPh2 CHo);
1
131.81 (d, JPC = 153 Hz, PPh2 Cipso), 177.47 (C2H).
31P{1H} NMR (CDCl3): d 42.4 (s). IR (Nujol, cmꢀ1):
1678 s, 1295 s, 1241 w, 1222 w, 1105 m, 1078 w, 998
m, 866 m, 840 m, 814 w, 742 m, 732 m, 707 m, 690 m,
643 w, 601 w, 499 w, 488 w. MS (direct inlet), m/z (rel-
ative abundance): 461 (24.7), 460 (83.2), 428 (8.2), 416
(16.7), 396 (11.7), 395 (48.2), 351 (17.2), 338 (13.7),
273 (10.3), 244 (11.5), 243 (55.9), 217 (9.6), 199 (15.3),
185 (10.7), 183 (16.2), 149 (12.8), 121 (8.8), 105 (53.0),
92 (80.1), 91 (100.0), 69 (25.0), 56 (11.5). HR MS: calcd.
for C24H2156FeO2PS 460.0349, found 460.0334.
1
M.p. 120–122 ꢁC (dec.). H NMR (CDCl3): d 3.57
2
2
(virtual t, JHH ꢂ JPH ꢂ 14.8 Hz, 1H, CH2), 4.17 (s,
5H, C5H5), 4.30 (apparent t, J ꢂ 2.6 Hz, 1H, C5H3),
2
2
4.42 (dd, JHH = 15.1 Hz, JPH = 10.6 Hz, 1H, CH2),
4.46 (m, 1H, C5H3), 4.75 (m, 1H, C5H3), 7.34–7.80 (m,
10H, PPh2). 13C{1H} NMR (CDCl3): d 31.13 (d,
1JPC = 67 Hz, CH2), 70.32 (C5H3 CH), 71.03 (C5H5),
4.9. Preparation of methyl rac-2-[(diphenylphosphino)
methyl]ferrocenecarboxylate (8)
A solution of diazomethane in diethyl ether (prepared
from 5 mmol of N-methyl-N-nitroso-p-toluenesulfon-
amide) was added to a solution of acid 1 (0.400 g,
0.93 mmol) in THF (10 mL). The mixture was stirred
3
71.72 (C5H3 CH), 73.66 (d, JPC = 2 Hz, C5H3 CH),
2
79.92 (d, JPC = 4 Hz, C5H3 C–CH2), 128.34, 128.55
(2· d, 3JPC = 12 Hz, PPh2 CHm); 130.86 (d,

M. Lamacˇ et al. / Journal of Organometallic Chemistry 690 (2005) 4285–4301
4297
2
at room temperature for 30 min and then evaporated
under vacuum. The residue was purified by column
chromatography (silica gel, diethyl ether). Evaporation
of a single band gave methyl ester 8 as an oil, which
solidified upon standing at 4 ꢁC. Yield: 0.404 g (98%).
According to NMR spectra, the product is contami-
nated with trace amount of the respective phosphine
oxide, which forms slowly in the air.
(CDCl3): d 8.64 (d, JRhC ꢂ 1 Hz, C5Me5), 28.95 (d,
1JPC = 21 Hz, C2), 68.70 (C5H3 C–CO2H), 70.09 (C5H3
CH), 70.28 (C5H3 CH), 70.99 (C5H5), 74.78 (C5H3
2
CH), 85.05 (d, JPC = 10 Hz, C5H3 C–CH2), 98.51 (dd,
1JRhC = 7 Hz, 2JPC = 3 Hz, C5Me5), 127.20 (d,
1JPC = 43 Hz, PPh2 Cipso), 127.64, 127.68 (2· d,
3JPC = 10 Hz, PPh2 CHm); 129.35 (d, JPC = 41 Hz,
1
4
PPh2 Cipso), 130.42, 130.90 (2· d, JPC = 2 Hz, PPh2
CHp); 134.17, 135.26 (2· d, JPC = 9 Hz, PPh2 CHo);
2
M.p. 58–60 ꢁC. 1H NMR (CDCl3): d 3.31 (dd,
2JHH = 13.7, JPH = 1.5 Hz, 1H, CH2), 3.74 (s, 3H,
176.05 (CO2H). 31P{1H} NMR (CDCl3): d 35.1 (d,
1JRhP = 141 Hz). IR (Nujol, cmꢀ1): 1677 s, 1635 sh,
1399 w, 1298–1289 m, 1250 w, 1236 w, 1215 w, 1183
w, 1157 w, 1107 w, 1098 m, 1071 w, 1026 w, 1000 w,
861 w, 825 m, 813 w, 744 s, 725 m, 696 m, 661 w, 615
w, 562 w, 521 w, 505 m, 487 m, 447 m. FAB+ (thioglyc-
erol–glycerol), m/z: 701 ([M ꢀ Cl]+), 666 ([M ꢀ 2Cl]+);
M+ not observed. HR MS (FAB): calcd. for
C34H3635Cl56FeO2PRh 701.0546, found 701.0539; calcd.
for C34H3656FeO2PRh 666.0857, found 666.0880.
2
2
CO2Me), 3.89 (d, JHH = 13.7, 1H, CH2), 4.00 (m, 1H,
C5H3), 4.11 (s, 5H, C5H5), 4.17 (apparent t, J ꢂ 2.7 Hz,
1H, C5H3), 4.68 (m, 1H, C5H3), 7.25–7.46 (m,
10H, PPh2). 13C{1H} NMR (CDCl3): d 28.98 (d,
1JPC = 15 Hz, CH2), 51.31 (CO2Me), 68.88 (d,
3JPC = 2 Hz, C5H3 C–CO2Me), 69.30 (C5H3 CH),
3
70.12 (C5H3 CH), 70.47 (C5H5), 72.99 (d, JPC = 5 Hz,
2
C5H3 CH), 87.46 (d, JPC = 16 Hz, C5H3 C–CH2),
3
128.16, 128.25 (2· d, JPC = 3 Hz, PPh2 CHm); 128.38,
2
128.91 (2· PPh2 CHp); 132.24 (d, JPC = 18 Hz,
2
PPh2CHo), 133.68 (d, JPC = 20 Hz, PPh2 CHo),
4.11. Preparation of dichloro-{methyl rac-2-[(diphenyl-
phosphino-jP)methyl]ferrocenecarboxylate}-(g5-
pentamethylcyclopentadienyl)rhodium(III) (10)
1
138.17, 138.93 (2· d, JPC = 15 Hz, PPh2 Cipso); 172.58
(CO2Me). 31P{1H} NMR (CDCl3): d ꢀ10.1 (s). IR (Nu-
jol, cmꢀ1): 1704 s, 1403 w, 1366 sh, 1287 s, 1216 m, 1101
m, 1075–1069 w, 1015 w, 997 w, 933 w, 862 w, 827 w,
775 w, 757 w, 742 m, 695 m, 519 w, 507 w, 494 w, 472
w, 464 w, 432 w. MS (direct inlet), m/z (relative abun-
dance): 443 (12.6), 442 (40.9), 306 (9.4), 258 (17.9), 257
(100.0), 183 (7.8), 121 (4.7), 105 (43.9), 56 (3.4). HR
MS: calcd. for C25H2356FeO2P 442.0785, found
442.0764.
A solution of [{(g-Cl)RhCl(g5-C5Me5)}2] (62 mg,
0.10 mg) in chloroform (10 mL) was mixed with a solu-
tion of phosphinoester 8 (89 mg, 0.20 mmol) in the same
solvent (10 mL). The reaction mixture was stirred at
room temperature for 1 h and then evaporated under re-
duced pressure. The solid residue was dissolved in chlo-
roform (3 mL), the solution was filtered and crystallized
by addition of hexane and standing overnight at ꢀ18 ꢁC
to give 10 as a dark red crystalline solid, which was fil-
tered off and dried in air. Yield: 106 mg (71%).
4.10. Preparation of dichloro-{rac-2-[(diphenyl-
phosphino-jP)methyl]ferrocenecarboxylic acid}-(g5-
pentamethylcyclopentadienyl)rhodium(III) (9)
M.p. dec. above 120 ꢁC. 1H NMR (CDCl3): d 1.33 (d,
3JRhH = 3.5 Hz, 15H, C5Me5), 3.39 (s, 3H, CO2Me),
3.78 (m, 1H, C5H3), 4.05 (apparent t, J ꢂ 2.6 Hz, 1H,
A solution of [{(l-Cl)RhCl(g5-C5Me5)}2] (62 mg,
0.10 mmol) in dichloromethane (10 mL) was added to
a solution of carboxyphosphine 1 (86 mg, 0.20 mmol)
in the same solvent (10 mL). The mixture was stirred
at room temperature for 1 h and evaporated under vac-
uum. The residue was redissolved in dichloromethane
(3 mL), the solution was layered with hexane and al-
lowed to crystallized by diffusion at room temperature.
Orange red needles of complex 9, which separated after
several days, were filtered off, washed with hexane and
dried in air. Yield: 141 mg (96%). (Note: in repeated syn-
theses, dichloromethane was replaced with chloroform
and the product was precipitated with excess hexane
without lowering the yield or product purity).
2
C5H3), 4.07 (s, 5H, C5H5), 4.21 (dd, JHH = 15.5,
2JPH = 8.3 Hz, 1H, CH2), 4.46 (dd, JHH = 15.5,
2
2JPH = 7.0 Hz, 1H, CH2), 4.52 (m, 1H, C5H3), 7.22–
7.94 (m, 10H, PPh2). 13C{1H} NMR (CDCl3): d 8.59
2
1
(d, JRhC ꢂ 1 Hz, C5Me5), 29.07 (d, JPC = 21 Hz,
CH2), 50.98 (CO2Me), 69.70 (C5H3, CH), 69.83 (C5H3,
CH), 70.53 (C5H5), 71.61 (C–COOH, C5H3), 73.01
(C5H3, CH), 83.82 (d, JPC = 10 Hz, C–CH2C5H3),
98.50 (dd, JRhC = 7 Hz, JPC = 3 Hz, C5Me5), 125.40
2
1
2
1
(d, JPC = 42 Hz, Cipso PPh2), 127.14, 127.93 (2· d,
3JPC = 10 Hz, Cm PPh2); 130.32 (d, JPC = 2 Hz, Cp
4
1
PPh2), 131.00 (d, JPC = 40 Hz, Cipso PPh2), 131.24 (d,
4JPC = 2 Hz, Cp PPh2), 132.76 (d, JPC = 7 Hz, CHo
2
M.p. dec. above 240 ꢁC. 1H NMR (CDCl3): d 1.36 (d,
3JRhH = 3.4 Hz, 15H, C5Me5), 3.87 (m, 1H, C5H3), 4.05
(apparent t, J ꢂ 2.7 Hz, 1H, C5H3), 4.13 (s, 5H, C5H5),
PPh2), 136.33 (d, JPC = 10 Hz, CHo PPh2), 171.69
2
(COOMe). 31P{1H} NMR (CDCl3):
d 35.0 (d,
1JRhP = 142 Hz). IR (Nujol, cmꢀ1): 1712 m, 1687 s,
1506 w, 1408 w, 1296 s, 1248 w, 1233 m, 1213 w, 1194
w, 1174 m, 1159 w, 1122 w, 1107 w, 1099 m, 1080 w,
1015 m, 861 w, 846 w, 836 w, 824 w, 777 w, 752 sh,
2
2
4.25 (dd, JHH = 15.3, JPH = 9 Hz, 1H, CH2), 4.54 (m,
2
2
1H, C5H3), 4.56 (dd, JHH = 15.3, JPH = 7 Hz, 1H,
CH2), 7.33–7.88 (m, 10H, PPh2). 13C{1H} NMR

4298
M. Lamacˇ et al. / Journal of Organometallic Chemistry 690 (2005) 4285–4301
744 s, 704 sh, 697 m, 660 w, 612 w, 522 w, 504 m, 489 m,
445 m. FAB+ (thioglycerol–glycerol), m/z: 751
([M ꢀ Cl]+), 680 ([M ꢀ 2Cl]+); M+ not observed. HR
MS (FAB): calcd. for C35H3835Cl56FeO2PRh 715.0702,
found 715.0689; calcd. for C35H3856FeO2PRh
680.1014, found 680.0997.
C5H5), 4.69 (m, 1H, C5H3), 7.29–7.82 (m, 10H, PPh2).
3C{1H} NMR (CDCl3): d 26.60 (s, PCy3 c-CH2),
3
27.57 (d, JPC = 10 Hz, PCy3 b-CH2), 29.72 (dd,
2
1JPC = 18 Hz, JRhC ꢂ 2 Hz, CH2PPh2), 30.23 (d,
1
2JPC = 38 Hz, PCy3 a-CH2), 33.45 (d, JPC = 18 Hz,
3
PCy3 CH), 66.37 (C5H3 CH), 69.80 (d, JPC = 2 Hz,
C5H3 CH), 70.59 (C5H5), 72.01 (C5H3 CH), 77.44 (d,
2
4.12. Attempted preparation of O,P-chelate complexes by
deprotonation of 9
3JPC = 7 Hz, C5H3 C–COOH), 85.55 (d, JPC = 2 Hz,
1
C5H3 C–CH2), 127.97, 128.78 (2· d, JPC = 9 Hz, PPh2
4
Cm); 130.30, 130.34 (2· d, JPC = 2 Hz, PPh2 CHp);
3
Butyl lithium (0.1 mL 2.5 M in hexanes, 0.25 mmol)
was added to a solution of complex 9 (148 mg,
0.20 mmol) in THF (10 mL) at room temperature. After
stirring for 24 h, the volatiles were removed under vac-
uum and the residue was subjected to column chroma-
tography on silica gel using dichloromethane–methanol
(10:1) as the eluent. NMR analysis of the fractions col-
lected indicated the presence of unchanged 9 and a two
compounds in a ratio of ca. 10:1, which were tentatively
assigned to diastereoisomers of chloro-{rac-2-[(diph-
enylphosphino-jP)methyl]ferrocenecarboxylate-jO}-(g5-
pentamethylcyclopentadienyl)rhodium(III) (11). Subse-
quent attempts to purify the obtained material by
crystallization or chromatography gave either intracta-
ble mixtures or the starting complex 9.
132.58, 133.72 (2· d, JPC = 11 Hz, PPh2 CHm); 175.28
1
2
(C@O), 190.11 (dt, JRhC = 72 Hz, JPC = 16 Hz,
C„O); the Cipso (PPh2) signals are obscured by other
phenyl resonances. 31P{1H} NMR (CDCl3): d 32.8
1
2
(dd, JRhP = 128 Hz, JPP = 322 Hz, PPh2), 40.9 (dd,
RhP = 126 Hz, JPP = 322 Hz, PCy3). IR (Nujol,
1
2
cmꢀ1): 1956 vs, 1624 w, 1603 s, 1582 m, 1564 w, 1398
vw, 1351 sh, 1331 m, 1314 w, 1301 w, 1246 w, 1176 w,
1101 w, 1043 w, 1028 vw, 1000 w, 852 vw, 830 w, 783
w, 745–733 m str, 693 w, 591 w, 557 vw, 514 vw, 488
w, 466 vw. Analysis calcd. for C43H53FeO3P2Rh Æ H2O:
60.29% C, 6.47% H; found 60.25% C, 6.43% H.
4.14. X-ray crystallography
NMR data for the more abundant new component:
Crystals suitable for diffraction measurements have
been obtained by crystallization from hot hexane (4: yel-
low plate, 0.06 · 0.13 · 0.25 mm3), ca. 50% aqueous ace-
tic acid (1: rusty orange plate, 0.05 · 0.13 · 0.25 mm3; 9:
red prism, 0.10 · 0.15 · 0.28 mm3), and methanol (sol-
vated 12: tiny yellow needle: 0.03 · 0.05 · 0.30 mm3),
or by liquid-phase diffusion from chloroform–hexane
(6: rusty orange block, 0.23 · 0.25 · 0.30 mm3), dichlo-
romethane–hexane (7: orange plate, 0.13 · 0.28 ·
0.50 mm3), and ethyl acetate–hexane (10: red prism,
0.13 · 0.18 · 0.23 mm3). Full-set diffraction data
3
1H NMR (CDCl3): d 1.56 (d, JRhH = 3.4 Hz, 15H,
2
2
C5Me5), 3.02 (dd, JPH = 16.7, JHH = 12.6 Hz, 1H,
CH2), 3.37 (m, 1H, C5H3), 3.83 (apparent t, J ꢂ 2.6 Hz,
2
1H, C5H3), 4.12 (s, 5H, C5H5), 4.42 (dd, JHH = 12.5,
2JPH = 9.3 Hz, 1H, CH2), 4.78 (m, 1H, C5H3), 6.98–
7.65 (m, 10H, PPh2). 31P{1H} NMR (CDCl3): d 41.0
1
(d, JRhP = 149 Hz). The minor component: 31P{1H}
1
NMR (CDCl3): d 41.4 (d, JRhP = 151 Hz).
4.13. Synthesis of [SP-4-2]-carbonyl-[rac-2-{(diphenyl-
phosphino)methyl}ferrocenecarboxylato-j2O,P]-
tricyclohexylphosphinerhodium(I) (12)
( h
k
l, h 6 27.5ꢁ) were collected on a Nonius Kap-
pa CCD diffractometer equipped with a Cryostream
Cooler (Oxford Cryosystems) using graphite monochro-
˚
To a warm solution [Rh(acac)(CO)(PCy3)] (51 mg,
0.10 mmol) in butan-2-one (3 mL) was added acid 1 dis-
solved in the same solvent (47 mg, 0.11 mmol in 3 mL)
and the mixture was heated at reflux for 5 min. The reac-
tion solution was cooled to room temperature and the
volatiles were removed under vacuum. The residue was
immediately dissolved in methanol (3 mL; the product
starts to crystallize instantly) and the solution was al-
lowed to crystallize overnight at ꢀ18 ꢁC. The separated
yellow microcrystalline product was filtered off, washed
with methanol and diethyl ether and dried in air. Yield:
71 mg, 85%; characterized as the solvate 12 Æ 0.7H2O.
matized Mo Ka radiation (k = 0.71073 A) and analyzed
with HKL program package [36]. The data for 2, solvated
10 and 11 were corrected for absorption by a numerical
method based on intensity variation for multiply mea-
sured diffractions as incorporated in the diffractometer
software (SORTAV routine [37]). The structures were
solved by direct methods (SIR97 [38]) and refined by
weighted full-matrix least-squares procedure on F2
(SHELXL97 [39]).
All non-hydrogen atoms were refined with aniso-
tropic thermal motion parameters. Carboxylic hydrogen
atoms in 1 and 6 as well as the hydroxyl hydrogen atoms
in 4 were identified on difference Fourier maps and iso-
tropically refined. The position of acidic hydrogen in 7
was located similarly and refined with Uiso(H) =
1.2Ueq(O). Carboxylic hydrogen atom in 9 was identified
on a difference Fourier map and subsequently refined
1
M.p. 149–151 ꢁC (dec.). H NMR (CDCl3): d 1.16–
2.34 (m, 33H, PCy3), 3.22 (ddd, J = 13.6, 13.5, 5.1 Hz,
1H, CH2PPh2), 3.44 (m, 1H, C5H3), 3.49 (br s, 1.4H,
H2O), 3.91 (apparent t, J ꢂ 2.5 Hz, 1H, C5H3), 3.96
(dd, J = 12.8, 5.2 Hz, 1H, CH2PPh2), 4.13 (s, 5H,

Table 6
Crystallographic data and data collection and structure refinement parameters for 4, 1, 6 Æ CHCl3, 7 Æ 1/2CH2Cl2, 9, 10, and 12
Compound
4
1
6 Æ CHCl3
7 Æ 1/2CH2Cl2
9
10
12
Formula
M (g molꢀ1
C
294.96
11H11BrFeO
C24H21FeO2P
428.23
C25H22Cl3FeO3Pf
563.60
C24.5H22ClFeO2PSg
502.75
C34H36Cl2FeO3.5PRhh
761.26
C35H38Cl2FeO2PRh
751.28
C43H53FeO3.7P2Rhj
849.75
)
Crystal system
Space group
Monoclinic
C2/c (no. 15)
26.0392(5)
6.7871(1)
Monoclinic
P21/c (no. 14)
8.7357(3)
19.3632(6)
11.9639(3)
Triclinic
Triclinic
Monoclinic
P21/n (no. 14)
10.6862(1)
10.2992(1)
30.7045(4)
Monoclinic
P21/n (no. 14)
9.1402(1)
32.6789(5)
11.6107(2)
Orthorhombic
P212121 (no. 19)
11.3304(2)
14.2815(3)
26.1049(5)
ꢀ
ꢀ
P1 ðno: 2Þ
P1 ðno: 2Þ
˚
a (A)
10.0374(3)
10.8070(3)
11.6368(3)
77.978(2)
80.357(2)
83.161(2)
2
7.0924(2)
12.6061(3)
14.2396(4)
106.050(1)
93.817(1)
99.914(2)
2
˚
b (A)
˚
c (A)
25.1973(5)
a (ꢁ)
b (ꢁ)
c (ꢁ)
Z
104.184(1)
102.133(2)
95.4566(8)
111.8426(8)
16
4317.4(1)
1.815
150(2)
5.061
0.591–0.731
30,594, 4.5
4937/3981
3.29
4.80, 7.95
0.52, 0.68
4
4
4
4
3
˚
V (A )
1978.5(1)
1.438
150(2)
1.438
1212.52(6)
1.544
150(2)
1196.43(6)
1.396
150(2)
3364.00(6)
1.503
150(2)
3219.05(8)
1.550
150(2)
4224.2(1)
1.336
150(2)
0.847
Dcalc (g mLꢀ1
T (K)
)
l (Mo Ka) (mmꢀ1
)
1.045
0.914
1.162
1.210
Ta
–
–
0.591–0.731
21,465, 3.0
5493/4716
4.21
5.12, 12.1
0.83, ꢀ0.83i
0.798–0.894
47,798, 4.6
7691/6442
3.96
5.10, 10.4
1.34, ꢀ0.74i
0.644–0.935
40,462, 5.3
7359/5637
3.49
5.79, 7.28
0.63, ꢀ0.52
–
e
e
e
Collected diffrations, Rint (%)b
Unique/observedc diffractions
R (observed data) (%)d
36,709, 7.3
4545/2758
4.90
10.24, 12.14
0.42, ꢀ0.42
18,715, 2.6
5549/4877
3.36
4.04, 8.41
0.55, ꢀ0.57
58,572, 11.9
7442/5597
4.83
8.52, 11.1
0.57, ꢀ0.41
R, wR (ꢀal3l data) (%)d
˚
Dq (e A
)
a
The range of transmission coefficients.
P
P
b
c
d
e
f
Rint
¼
P
jF o2 ꢀ F o2ðmeanÞj= F 2o, where F 2oðmeanÞ is the average intensity for symmetry equivalent diffractions.
Diffractions with I0 > 2r(I0).
P
P
P
2
2 1=2
R = iFoi ꢀ iFci/ Foi, wR ¼ ½ fwðF 2o ꢀ F c2Þ g= wðF o2Þ ꢃ
.
Not corrected.
C24H21FeO3P Æ CHCl3.
g
h
i
C24H21FeO2PS Æ 1/2CH2Cl2.
C34H36Cl2FeO2PRh Æ O1.5
Residuals in the space accommodating the disordered solvate molecules.
C43H53FeO3P2Rh Æ O0.7
.
j
.

4300
M. Lamacˇ et al. / Journal of Organometallic Chemistry 690 (2005) 4285–4301
using a riding model and assigned Uiso(H) = 1.2Ueq(O).
Other hydrogen atoms were included in the calculated
positions and refined using the riding model [C–H bond
lengths: 0.96 (methyl), 0.97 (methylene), 0.98 (methine),
and 0.93 (aromatic); Uiso(H) = 1.5Ueq(C) (methyl) or
Uiso(H) = 1.2Ueq(C) (all other)].
References
[1] (a) A. Togni, R.L. Haltermann (Eds.), Metallocenes, VCH,
Weinheim, 1998;
(b) A. Togni, T. Hayashi (Eds.), Ferrocenes – Homogenous
Catalysis, Organic Synthesis, Materials Science, VCH, Weinheim,
1995;
The structure of 7 contains molecules of solva-
ting dichloromethane. The solvate molecules are
extensively disordered in channels defined by the
non-polar phenyl and ferrocene moieties, running par-
allel to the crystallographic a-axis. The disordered sol-
vent molecules were modelled over two independent
positions with fractional occupancies 0.40 and 0.10,
thus, giving one dichloromethane molecule per the
unit cell.
(c) C.J. Richards, A.J. Locke, Tetrahedron: Asymm. 9 (1998)
2377;
(d) T.J. Colacot, Chem. Rev. 103 (2003) 3101.
[2] R.C.J. Atkinson, V.C. Gibson, N.J. Long, Chem. Soc. Rev. 33
(2004) 313.
ˇ
´
ˇ
´
´
[3] J. Podlaha, P. Steˇpnicˇka, I. Cısarova, J. Ludvık, Organometallics
15 (1996) 543.
[4] A. Bader, E. Lindner, Coord. Chem. Rev. 108 (1991) 27.
ˇ
[5] (a) P. Steˇpnicˇka, R. Gyepes, O. Lavastre, P.H. Dixneuf, Organo-
metallics 16 (1997) 5089;
ˇ
´ˇ
(b) P. Steˇpnicˇka, J. Podlaha, R. Gyepes, M. Polasek, J. Organo-
The crystals of 9 obtained from aqueous acetic acid
accommodate water molecules in the space close to
the carboxyl groups of the ligands. The water mole-
cules, which seem to occupy various positions with
fractional occupancies (though in the usual hydrogen
bond distances), were included in the refined model
only as oxygen atoms with partial occupancies (0.8,
0.5, and 0.2; the first two anisotropically and the least
populated with an isotropic thermal motion para-
meter).
met. Chem. 552 (1998) 293;
ˇ
(c) P. Steˇpnicˇka, R. Gyepes, J. Podlaha, Collect. Czech. Chem.
Commun. 63 (1998) 64;
ˇ
´
ˇ
´
´
(d) P. Steˇpnicˇka, I. Cısarova, J. Podlaha, J. Ludvık, M. Nejezch-
leba, J. Organomet. Chem. 582 (1999) 319;
ˇ
ˇ
(e) J. Pinkas, Z. Bastl, M. Slouf, J. Podlaha, P. Steˇpnicˇka, New J.
Chem. 25 (2001) 1215;
ˇ
´
´
´
ˇ
´
ˇ
ˇ
(f) L. Lukesˇova, J. Ludvık, I. Cısarova, P. Stepnicka, Collect.
Czech. Chem. Commun. 65 (2000) 1897.
ˇ
´
ˇ
´
ˇ
ˇ
[6] K. Mach, J. Kubisˇta, I. Cısarova, P. Stepnicka, Acta Crystallogr.
C58 (2002) m116.
ˇ
´
ˇ
´
[7] P. Steˇpnicˇka, I. Cısarova, J. Chem. Soc., Dalton Trans. (1998)
The solvate molecules in hydrate 12 Æ 0.7H2O were re-
fined similarly (occupancies 0.3, 0.3, and 0.2; all with
isotropic thermal motion parameters). The crystals suf-
fered from racemic twinning. The refinement revealed
practically identical contributions from the enantiomeric
forms (0.488:0.512).
Selected crystallographic data are given in Table 6.
The geometric data presented and the molecular draw-
ings were obtained with a recent version of PLATON
program [40].
2807.
ˇ
´
ˇ
´
[8] P. Steˇpnicˇka, M. Lamacˇ, I. Cısarova, Polyhedron 23 (2004)
921.
ˇ
ˇ
[9] P. Steˇpnicˇka, J. Demel, J. Cejka, J. Mol. Catal. A: Chem. 224
(2004) 161.
ˇ
[10] P. Steˇpnicˇka, New J. Chem. 26 (2002) 567.
[11] (a) J.M. Longmire, B. Wang, X. Zhang, Tetrahedron Lett. 41
(2000) 5435;
(b) S.-L. You, X.-L. Hou, L.-X. Dai, B.-X. Cao, J. Sun, Chem.
Commun. (2000) 1933;
(c) Deng, X.-L. Hou, L.-X. Dai, J. Organomet. Chem. 637–639
(2001) 845.
[12] (a) Deng, X.-L. Hou, L.-X. Dai, J. Organomet. Chem. 637–639
(2001) 762;
(b) S.-L. You, X.-L. Hou, L.-X. Dai, X.-Z. Zhu, Org. Lett. 3
(2001) 149;
5. Supplementary material
(c) J.M. Longmire, B. Wang, X. Zhang, J. Am. Chem. Soc. 124
(2002) 13400;
(d) B. Breit, D. Breuninger, J. Am. Chem. Soc. 126 (2004) 10244.
Crystallographic data excluding structure factors
have been deposited with the Cambridge Crystallo-
graphic Data Centre. Copies of the data can be obtained
upon application to The Director, CCDC, 12 Union
Road, Cambridge, CB2 1EZ, UK (fax: +44 1223
336408; e-mail: deposit@ccdc.cam.ac.uk). CCDC refer-
ence numbers: CCDC-266155 (4), -266156 (1), -266157
(6 Æ CHCl3), -266158 (7 Æ 1/2CH2Cl2), -266159 (9 hy-
drate), -266160 (10), and -266161 (12 hydrate).
ˇ
´
ˇ
´
[13] P. Steˇpnicˇka, I. Cısarova, Organometallics 22 (2003) 1728.
ˇ
´
ˇ
´
[14] P. Steˇpnicˇka, I. Cısarova, Z. Anorg. Allg. Chem. 630 (2004) 1321.
ˇ
[15] P. Steˇpnicˇka, Inorg. Chem. Commun. 7 (2004) 426.
[16] L. Xiao, K. Mereiter, W. Weissensteiner, M. Widhalm, Synthesis
(1999) 1354.
[17] M. Widhalm, U. Nettekoven, K. Mereiter, Tetrahedron: Asymm.
10 (1999) 4369.
[18] G. Marr, R.E. Moore, B.W. Rockett, J. Chem. Soc. Sect. C
(1968) 24.
[19] A. Togni, C. Breutel, A. Schnyder, F. Spindler, H. Landert, A.
Tijani, J. Am. Chem. Soc. 116 (1994) 4062, For other examples,
see [1].
Acknowledgement
[20] W.R. Cullen, E.B. Wickenheiser, Can. J. Chem. 68 (1990) 705.
ˇ
[21] R. Sebesta, Ph.D. Thesis, Comenius University, Bratislava,
This work was financially supported by the Grant
Agency of Charles University (Grant No. 318/2005/B-
CH/PrF)
Slovakia, 2003.
[22] H.-O. Kalinowski, S. Berger, S. Braun, 13C-NMR-Spektroskopie,
Thieme, Stuttgart, 1984, pp. 199–200, 530–538.

M. Lamacˇ et al. / Journal of Organometallic Chemistry 690 (2005) 4285–4301
4301
[23] N.J. Goodwin, W. Henderson, B.K. Nicholson, Inorg. Chim.
Acta 295 (1999) 18.
[24] (a) M. Cais, M.S. Lupin, in: F.G.A. Stone, R. West (Eds.), Adv.
Organomet. Chem., Academic Press, New York, 1970, pp. 211–
333;
[32] P.S. Pregosin, R.W. Kunz, 31P and 13C NMR Data of
Transition Metal Phosphine Complexes, in NMR Basic Prin-
ciples and Progress, Springer, Berlin, 1979, see also data in
[7,32].
[33] D. Cremer, J.A. Pople, J. Am. Chem. Soc. 97 (1975)
1354.
[34] D. Lednicer, C.R. Hauser, in: H.E. Baumgarten (Ed.), Org.
Synth., Coll., 5, Wiley, New York, 1973, pp. 434–436.
[35] C. White, D. Yates, P.M. Maitlis, in: R.N. Grimes (Ed.), Inorg.
Synth., 13, McGraw-Hill, New York, 1972, pp. 47–55.
[36] Z. Otwinowski, W. Minor, HKL DENZO and SCALEPACK Program
Package, Nonius BV, Delft, The Netherlands, 1997;
For a reference, see: Z. Otwinowski, W. Minor, Meth. Enzymol.
276 (1997) 307.
(b) A. Mandelbaum, M. Cais, Tetrahedron Lett. (1964) 3847;
(c) D.T. Roberts Jr., W.L. Little, M.M. Bursey, J. Am. Chem.
Soc. 89 (1967) 6156.
ˇ
´ˇ
ˇ
ˇ
[25] M. Polasek, P. Stepnicka, J. Mass. Spectrom. 33 (1988) 739.
[26] (a) D.H. Williams, R.S. Ward, R.G. Cooks, J. Am. Chem. Soc.
90 (1968) 966;
(b) K.A. Asker, A.M. Greenway, K.R. Seddon, A.A. Shimran, J.
Organomet. Chem. 354 (1998) 257.
ˇ
´
ˇ
´
[27] P. Steˇpnicˇka, I. Cısarova, New J. Chem. 26 (2002) 1389.
ˇ
[28] P. Steˇpnicˇka, T. Basˇe, Inorg. Chem. Commun. 4 (2001) 682.
[37] R.H. Blessing, J. Appl. Crystallogr. 30 (1997) 421.
[38] 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. 32 (1999) 115.
[39] G.M. Sheldrick, SHELXL97, Program for Crystal Structure Refine-
ment from Diffraction Data, University of Go¨ttingen, Germany,
1997.
[29] M.C. Etter, J.C. MacDonald, Acta Crystallogr. B46 (1990) 256.
[30] Complex 11 possesses a stereogenic rhodium atom and, hence, it
should give rise to a mixture of two diastereoisomeric pairs:
(RRh,Sp)/(SRh,Rp) and (RRh,Rp)/(SRh,Sp), observable in NMR
spectra.
´
´
[31] (a) A. Jegorov, B. Kratochvıl, V. Langer, J. Podlahova, Inorg.
Chem. 23 (1984) 4288;
(b) A. Jegorov, J. Podlaha, J. Podlahova, F. Turecek, J. Chem.
Soc., Dalton Trans. (1990) 3259.
[40] A.L. Spek, PLATON A Multipurpose Crystallographic Tool,
Utrecht University, The Netherlands, 2003. Available from:
<http://www.cryst.chem.uu.nl/platon/> .
´
ˇ