Synthesis of a new C3-symmetric tripodal P4-tetradentate ligand and its application to the formation of chiral metal complexes

Article abstract of DOI:10.1021/om900923t

A novel C₃-symmetric tetradentate tripodal ligand with phosphorus as coordinating atoms has been synthesized in good yields. Its coordination ability through the four phosphorus atoms, three at the arms and one at the bridging position, is shown by formation of rigid Pd(II) and Rh(I) complexes. These C₃-iymmetric complexes are intrinsically chiral; experimental evidence for their configurational stability is included.

Full text of DOI:10.1021/om900923t

Organometallics 2010, 29, 703–706 703
DOI: 10.1021/om900923t
Synthesis of a New C3-Symmetric Tripodal P4-Tetradentate Ligand and
Its Application to the Formation of Chiral Metal Complexes
†
Dirk Penno, Igor O. Koshevoy, Francisco Estevan, Mercedes Sanau,
†
†
ꢀ †
†
Maria Angeles Ubeda, and Julia Perez-Prieto*
,‡
ꢀ
†
´
ꢀ
´
Departamento de Quımica Inorganica, Facultad de Quımica, Universidad de Valencia,
Dr. Moliner 50, 46100 Burjassot, Valencia, Spain and Instituto de Ciencia Molecular (ICMOL),
´
Polıgono La Coma s/n, 46980 Paterna, Valencia, Spain
‡
Received October 21, 2009
Chart 1. C,P3-Tetradentate Ligand
Summary: A novel C3-symmetric tetradentate tripodal ligand
with phosphorus as coordinating atoms has been synthesized
in good yields. Its coordination ability through the four phos-
phorus atoms, three at the arms and one at the bridging
position, is shown by formation of rigid Pd(II) and Rh(I)
complexes. These C3-symmetric complexes are intrinsically
chiral; experimental evidence for their configurational stabi-
lity is included.
The synthesis of tripodal ligands and their facial coordina-
tion to metals to generate C3-symmetric complexes are of
interest in the research area of selective catalysis. In parti-
cular, C3-symmetric chiral complexes are of great signifi-
cance since, in principle, orders of rotational symmetry
higher than 2-fold would lead to an increased control of
stereochemistry.1,2 This type of complex is rather unusual,
and most of them are based on tripodal nitrogen,3 although
examples of coordination through phosphorus, oxygen,
selenium, and sulfur have also been reported.4 Gade et al.
emphasized the interest in ligands that can provide a rela-
tively rigid and well-defined geometry, such as 1,1,1-tris-
(oxazolinyl)alkane compounds, which facially coordinate as
a tridentate ligand to transition metals.5
The most common method for synthesizing C3-symmetric
chiral metal complexes is the coordination of chiral ligands
to the metal ion,1-6 although there are examples of chiral
complexes generated from achiral ligands.7 We have recently
reported the synthesis of a chiral Pd complex with a C3-sym-
metric propeller-shaped ligand without any chiral center; the
enantiomers are configurationally stable and can be isolated
by chiral HPLC. This Pd complex possesses a rigid phos-
phorus-tripodal ligand (HTIMP3, Chart 1),8 whose coordi-
nation to other metals, such as Mo, Ag, Ir, and Rh, via the
three phosphorus atoms has been also demonstrated.8,9 In
the cases of the Pd, Ir, and Rh complexes, there is an
additional coordination to the metal through the central
carbon bridge of the P-tripodal ligand; that is, the ligand
actually acts as a C,P3-tetradentante ligand.
*Corresponding author. Tel: þ34-963543050. Fax: þ34-963543274.
E-mail: julia.perez@uv.es.
(1) Nugent, W. A.; RajanBabu, T. V.; Burk, M. J. Science 1993, 259,
479.
Aimed at synthesis of new C3-symmetric ligands with
phosphorus coordinating atoms and with a view to obtaining
chiral C3-symmetric complexes of potential interest in cata-
lysis, we focused on the synthesis of new rigid tripodal
phosphanes using 3-methylindole as the starting material.
Herein we report the efficient synthesis of a new tripodal
P4-tetradentate ligand, namely, tris(2-diphenylphosphino)-
3-methyl-1H-indol-1-yl)phosphine (TIPP3), and an investi-
gation of its coordination to transition metals, in particular
Pd(II) and Rh(I). The structure of the ligand and that of
both metal complexes was confirmed by NMR spectroscopy
(1H, 13C, and 31P) and X-ray analysis of their crystal struc-
ture. NMR experiments demonstrated the axial chirality and
(2) Moberg, C. Angew. Chem., Int. Ed. 1998, 37, 248.
(3) (a) Forcato, M.; Lake, F.; Blazquez, M. M.; Renner, P.; Crisma,
M.; Gade, L. H.; Licini, G.; Moberg, C. Eur. J. Inorg. Chem. 2006, 1032.
(b) Hammes, B. S.; Ramos-Maldonado, D.; Yap, G. P. A.; Liable-Sands, L.;
Rheingold, A. L.; Young, V. G.; Borovik, A. S. Inorg. Chem. 1997, 36, 3210.
(c) Memmler, H.; Kauper, U.; Gade, L. H.; Stalke, D. Organometallics 1996,
15, 3637.
(4) (a) Parkin, G. New J. Chem. 2007, 31, 1996. (b) Brule, E.; Pei, Y.;
Lake, F.; Rahm, F.; Moberg, C. Mendeleev Commun. 2004, 14, 276. (c) Di
Furia, F.; Licini, G.; Modena, G.; Motterle, R.; Nugent, W. A. J. Org. Chem.
1996, 61, 5175. (d) Nugent, W. A.; Harlow, R. L. J. Am. Chem. Soc. 1994,
116, 6142. (e) Ward, T. R.; Venanzi, L. M.; Albinati, A.; Lianza, F.; Gerfin, T.;
Gramlich, V.; Ramos Tombo, G. M.; Gerardo, M. Helv. Chim. Acta 1991,
74, 983. (f) Burk, M. J.; Harlow, R. L. Angew. Chem., Int. Ed. Engl. 1990,
29, 1462.
(5) Gade, L. H.; Marconi, G.; Dro, C.; Ward, B. D.; Poyatos, M.;
Bellemin-Laponnaz, S.; Wadepohl, H.; Sorace, L.; Poneti, G. Chem.;
Eur. J. 2007, 13, 3058.
(6) Bringmann, G.; Breuning, M.; Pfeifer, R.-M.; Schreiber, P.
Tetrahedron: Asymmetry 2003, 14, 2225.
ꢀ
(8) Ciclosi, M.; Lloret, J.; Estevan, F.; Lahuerta, P.; Sanau, M.;
ꢀ
Perez-Prieto, J. Angew. Chem., Int. Ed. 2006, 45, 6741.
ꢀ
ꢀ
(9) (a) Ciclosi, M.; Lloret, J.; Estevan, F.; Sanau, M.; Perez-Prieto, J.
(7) (a) Zheng, J.; Yang, N.; Liu, W.; Yu, K. J. Mol. Struct. 2008, 873,
89. (b) Bailey, P. J.; Dawson, A.; McCormack, C.; Moggach, S. A.; Oswald,
I. D. H.; Parsons, S.; Rankin, D. W. H.; Turner, A. Inorg. Chem. 2005, 44,
8884.
Dalton Trans. 2009, 5077. (b) Ciclosi, M.; Estevan, F.; Lahuerta, P.;
ꢀ
Passarelli, V.; Perez-Prieto, J.; Sanaꢀu, M. Dalton Trans. 2009, 2290.
ꢀ
(c) Ciclosi, M.; Estevan, F.; Lahuerta, P.; Passarelli, V.; Perez-Prieto, J.;
Sanaꢀu, M. Adv. Synth. Catal. 2008, 350, 234.
r
2010 American Chemical Society
Published on Web 01/12/2010
pubs.acs.org/Organometallics

704 Organometallics, Vol. 29, No. 3, 2010
Penno et al.
Scheme 1. Preparation of Tris(2-diphenylphosphino)-3-methyl-
1H-indol-1-yl)phosphine, as Well as the Rh(I) and Pd(II)
Complexes
Figure 1. ORTEP view of TIPP3 (1). Hydrogen atoms are
omitted for clarity. Only the ipso C atoms of the phenyl rings
˚
are shown for clarity. Important bond distances (A) and angles
(deg): P-N(1), 1.729(7); P-N(2), 1.732(7); P-N(3), 1.739(8);
N(1)-P-N(2), 101.0(4); N(1)-P-N(3), 100.9(4); N(3)-P-N(2),
101.0(3).
configurational stability of the complexes at temperatures up
to 85 °C.
The ligand TIPP3 (1) was synthesized with a satisfactory
yield by treatment of 2-(diphenylphosphino)-3-methylin-
dole10 with n-butyllithium, followed by the addition of phos-
phorus trichloride (Scheme 1). The structure of this com-
pound was established by means of NMR spectroscopy (see
Figures S1 and S2 in the Supporting Information) and finally
confirmed by X-ray analysis of a single crystal grown in
CH2Cl2/hexane (Figure 1). The perspective view showed the
three-blade propeller shape of the molecule.11
Subsequently, the coordination chemistry of this new
tripodal tetradentate ligand to Pd and Rh was explored, as
these metals are the most promising for applications in
catalysis. Thus, TIPP3 easily reacted with bis(benzonitrile)-
palladium(II) dichloride at room temperature, yielding the
corresponding red, cationic metal complex [Pd(η4-PP3-
TIPP3)Cl]þ (Scheme 1), isolated as its chloride salt (2). This
compound shows a molar conductivity (ΛM) of 84 S cm2 mol-1
in dichloromethane at room temperature, similar to a 1:1
electrolyte.12
Figure 2. ORTEP view of the Pd(II) complex 2. Hydrogen
atoms are omitted for clarity. Only the ipso C atoms of the
˚
phenyl rings are shown for clarity. Important bond distances (A)
and angles (deg): Pd(1)-P, 2.153(2); Pd(1)-Cl(1), 2.361(2);
Pd(1)-P(1), 2.491(2); Pd(1)-P(2), 2.373(2); Pd(1)-P(3), 2.492(2);
P-Pd(1)-Cl(1), 176.38(9); Cl(1)-Pd(1)-P(1), 101.64(9).
The NMR spectra of 2 are in agreement with the symmetry
found in the X-ray structure. The 31P NMR spectrum
(Figure S3) shows a quadruplet at lower field for the central
phosphorus bridge and a doublet at higher field for the
pendant phosphorus atoms. In the 1H NMR spectrum
(Figure S4) the singlet at 1.67 ppm indicates the three methyl
substituents attached to the methine are equivalent.
In addition, TIPP3 was reacted with (1,5-cycloocta-
diene)rhodium(I) chloride dimer at room temperature, giv-
ing rise to the red, neutral [Rh(η4-PP3-TIPP3)Cl] complex 3
(Scheme 1 and Figure S5). The solid-state structure of 3
(Figure 3) was analyzed by X-ray diffraction of a single
crystal (grown in CH2Cl2/hexane), which demonstrated a
similar geometry to that of 2 (Table 1 compares selected
bond distances and angles of 2 and 3).
Single-crystal X-ray diffraction revealed that the geometry
of the metal complex is trigonal bipyramidal and the ligand is
tetracoordinated to the metal. The view along the 3-fold
molecular axis of the palladium complex revealed its axial
chirality (Figure 2). Table 1 summarizes selected bond dis-
tances and angles.
(10) Yu, J. O.; Lam, E.; Sereda, J. L.; Rampersad, N. C.; Lough, A. J.;
Browning, C. S.; Farrar, D. H. Organometallics 2005, 24, 37.
(11) For other examples of chiral phosphanes with similar symmetry
see: Benincori, T.; Marchesi, A.; Mussini, P. R.; Pilati, T.; Ponti, A.;
Rizzo, S.; Sannicolo, F. Chem.;Eur. J. 2009, 15, 86.
(12) Svorstol, H.; Hoiland, J.; Songstad Acta Chem. Scand. 1984,
B38, 885.
In addition, complex 2 was reacted with AgBF4 followed
by treatment with (R)-phenylethylamine. The 19F NMR
spectrum shows one signal at -154 ppm, which is indicative

Note
Organometallics, Vol. 29, No. 3, 2010 705
Table 1. Selected Crystal Structure Data for the Tripodal
Ligand 1 and Metal Complexes 2 and 3a
yields. A key feature of this ligand is the orientation and
steric demand of its pendant ligands, whose coordination
to Pd and Rh leads to new examples of rare inherently chiral
C3-symmetric metal complexes. These new complexes show a
unique configurational stability. Also of considerable impor-
tance is the stability of compounds 2 and 3 in solution, as
five-coordinated d8 complexes are usually unstable and are
sometimes proposed as intermediates in catalytic systems.14
ligand 1
Pd complex 2
Rh complex 3
˚
Distances (A)
(Pc-N)
1.729, 1.732, 1.660, 1.673,
1.739 1.680
2.153
1.681, 1.699,
1.700
2.106
2.314, 2.322,
2.378
2.430
(Pc-M)
(Ps-M)
2.373, 2.491,
2.492
2.361
Experimental Section
(M-Cl)
General Procedures. All manipulations were performed under
purified argon in standard (Schlenk) glassware. 2-Diphenylphos-
phino-3-methylindole was obtained according to the literature.10
All the other reagents were commercially available. Solvents
were of analytical grade and were dried according to standard
procedures. The 1H, 13C, 31P, and 19F NMR spectra were
recorded on a Bruker DRX-400 spectrometer (at 400, 100.5,
161.8, and 376.2 MHz, respectively), using tetramethylsilane
(1H and 13C NMR) or H3PO4 85% (31P NMR) as reference.
Chemical shifts are reported in ppm. The coupling constants (J)
are in hertz (Hz). Elemental analyses were provided by Centro de
Microanalisis Elemental, Universidad Complutense de Madrid.
Column chromatography was performed on silica gel (35-70 mesh).
Solvent mixtures are volume/volume mixtures, unless otherwise
specified. Conductivity measurements were made with a Crison
GLP 31 conductimeter at 25 °C.
Angles (deg)
(M-Pc-N)
(Pc-M-Ps)
109.8, 110.6, 111.2 111.4, 112.2, 112.9
82.71, 81.73, 79.90 81.00, 83.58, 82.93
a c=central, s=side arm, M=metal.
Synthesis of TIPP3 (1). n-Butyllithium (2.05 mL, 1.6 M in
hexane, 3.28 mmol) was slowly added to a solution of 2-diphe-
nylphosphino-3-methylindole (1 g, 3.17 mmol) in THF (25 mL)
at -78 °C. After stirring for 15 min at the same temperature, the
solution was warmed to room temperature and stirred for
another 15 min. After cooling again at -78 °C, PCl3 (92.5 mL,
1.06 mmol) was added. The solution was allowed to warm to
room temperature and subsequently refluxed for 5 h. The
solution was evaporated to dryness, leaving a light brown solid,
which was extracted with CH2Cl2 (50 mL) and filtered over
silica. The obtained colorless solution was concentrated under
reduced pressure, and upon addition of diethyl ether, the
product precipitated as a white solid (328 mg). Further pre-
cipitation from the mother solution yielded more compound
(148 mg). Yield: 476 mg (46%). Crystals suitable for single-
crystal X-ray diffraction were grown from a dichloromethane
solution of the product carefully layered with hexane.
Figure 3. ORTEP view of the Rh(I) complex 3. Hydrogen atoms
are omitted for clarity. Only the ipso C atoms of the phenyl rings
˚
are shown for clarity. Important bond distances (A) and angles
(deg): Rh(1)-P, 2.106(2); Rh(1)-Cl(1), 2.430(2); Rh(1)-P(1),
2.378(2); Rh(1)-P(2), 2.314(2); Rh(1)-P(3), 2.322(2); P-
Rh(1)-Cl(1), 173.65(8); Cl(1)-Rh(1)-P(1), 103.40(8).
of uncoordinated BF4. The formation of diastereoisomers
would lead to a doubling of the 31P NMR signals and
demonstrate the existence of the complex as a racemic mix-
ture. In fact, the 31P NMR spectrum of the complex shows
two signals of the same intensity, at -2.8 and -3.2 ppm, for
the pendant phosphines (Figure S6), which proves that the
axial chirality of the complex is retained in solution.
Inversion between P and M enantiomers of C3-symmetric
chiral metal complexes with ligands devoid of a chiral center
has been studied by NMR spectroscopy performed at dif-
ferent temperatures.13,7b The configurational stability of
complexes 2 and 3 was assessed by registering their NMR
spectra at temperatures ranging from -50 to 85 °C, using
either dichloromethane or toluene as the solvent. Complexes
2 and 3 possess a considerable intramolecular crowding
between the three methyl groups. 1H NMR spectra of these
complexes show the three methyl groups are equivalent.
Consequently, the indolyl groups are twisted in the same
sense. A broadening of the signals should have been expected
while the temperature was varied in the range -50 to 85 °C if
racemization occurred.
1H NMR (CDCl3): δ 1.76 (s, 9H), 6.49 (t, J=7.2, 6H), 6.64 (d,
J = 8.4, 3H), 6.93-7.19 (m, 27H), 7.24-7.29 (m, 3H), 7.53 (d,
J=7.8, 3H). 13C NMR (CDCl3): δ 10.7 (s, CH3), 114.0 (s, CH,
indolyl), 119.4 (s, CH, indolyl), 120.8 (s, CH, indolyl), 124.9 (s,
CH, indolyl), 125.8 (s, Cquart, indolyl), 127.2 (s), 127.9 (d, J =
5.5 Hz), 128.3 (d, J=7.9 Hz), 128.5 (s), 131.4 (d, J=18.1 Hz),
133.4 (d, J=42.4 Hz), 133.8 (d, J = 31.0 Hz), 134.2 (d, J = 20.7
Hz), 136.8 (d, J = 11 Hz, Cquart, indolyl), 136.9 (d, J = 9.7 Hz,
C
quart, indolyl), 142.0 (m, Cquart, indolyl). 31P NMR (CDCl3): δ
-30.0 (d, J = 197 Hz, 3P), 73.4 (q, J = 197 Hz, 1P). Anal. Calcd
for C63H51N3P4: C 77.24, H 5.43, N 4.43. Found: C 77.69,
H 5.28, N 4.31.
Synthesis of [Pd(η4-PP3-TIPP3)Cl]Cl (2). Tris(2-(diphenyl-
phosphino)-3-methyl-1-indolyl)phosphine (TIPP3) (50 mg,
0.051 mmol) was added to a solution of bis(benzonitrile)-
palladium(II) dichloride (20 mg, 0.051 mmol) in dichloro-
methane (20 mL). The color of the solution immediately chan-
ged from yellow to red. After stirring for 1 h, the solution
was evaporated to dryness, and the solid red residue was purified
by column chromatography (silica, 2 ꢀ 8 cm, chloroform to
In conclusion, a novel rigid C3-symmetric ligand with
phosphorus as coordinating atoms was synthesized in good
(14) (a) Crabtree, R. H. The Organometallic Chemistry of Transition
Metals, 2nd ed.; John Wiley and Sons: New York, 1994. (b) Koshevoy, I. O.;
(13) Chmura, A. J.; Chuck, C. J.; Davidson, M. G.; Jones, M. D.;
Lunn, M. D.; Bull, S. D.; Mahon, M. F. Angew. Chem., Int. Ed. 2007, 46,
2280.
€
Sizova, O. V.; Tunik, S. P.; Lough, A.; Poe, A. J. Eur. J. Inorg. Chem. 2005,
4516.

706 Organometallics, Vol. 29, No. 3, 2010
Penno et al.
chloroform/methanol, 10:1). The red band was collected and
evaporated to dryness. Recrystallization from dichloromethane/
diethyl ether gave a red microcrystalline solid. Yield: 47 mg,
82%. Crystals suitable for single-crystal X-ray diffraction were
grown from a dichloromethane solution of the product carefully
layered with hexane.
remove its contribution to the overall intensity data.16 An
improvement was observed in all refinement parameters and
residuals.
Proof of the Chirality of Complex 2. A methanol solution of
AgBF4 was added to a dichloromethane solution of complex 2.
The solution became a brighter red and a precipitate was
formed, which was filtered and dried. The 31P NMR spectrum
of the product (red solid) in CDCl3 showed two signals, one at
80 ppm (broad band, 1P) and the other at -1 ppm (doublet, 3P).
A drop of (R)-phenylethylamine was added to the NMR tube,
and the 31P NMR spectrum of the complex showed two signals
of the same intensity, at -2.8 and -3.2 ppm, for the pendant
phosphines (Figure S6).
1H NMR (CDCl3): δ 1.67 (s, 9H), 6.40 (d, J = 8.4, 3H),
6.92-6.96 (m, 6H), 7.02-7.07 (m, 6H), 7.18-7.24 (m, 6H),
7.38-7.42 (m, 15H), 7.48-7.51 (m, 3H), 7.58 (d, J = 8.0, 3H).
13C NMR (CDCl3): δ 10.1 (s), 112.6 (s, CH, indolyl), 121.9 (s,
CH, indolyl), 124.8 (s, CH, indolyl), 125.3 (m), 128.2 (m), 128.3
(s, CH, indolyl), 128.9 (m), 129.0 (m), 129.8 (m), 130.8 (s), 131.0
(m), 131.8 (m), 131.9 (s), 134.2 (m), 135.1 (m), 139.6 (m). 31P
NMR (CDCl3): δ -3.4 (d, J=8.4, 3P), 95.6 (q, J=8.4, 1P). MS
(FAB): m/z (%) 1114 (100), [M - Cl]þ; 1079 (5), [M - 2Cl]þ.
Synthesis of [Rh(η4-PP3-TIPP3)Cl] (3). Tris(2-(diphenyl-
phosphino)-3-methyl-1-indolyl)phosphine (TIPP3) (30 mg,
0.031 mmol) was added to a solution of (1,5-cyclooctadiene)-
rhodium(I) chloride dimer (7.9 mg, 0.016 mmol) in dichloro-
methane (10 mL). The color of the solution immediately chan-
ged from yellow to red. After stirring for 1 h, the solution
was evaporated to dryness and the solid red residue was puri-
fied by recrystallization from tetrahydrofuran/hexane, giving
a red microcrystalline solid. Yield: 33 mg, 97%. Crystals sui-
table for single-crystal X-ray diffraction were grown from a
dichloromethane solution of the product carefully layered with
hexane.
X-ray crystal structure data for 1: C63H51N3P4. rhombohe-
˚
˚
dral, space group R3, a=b=35.013(5) A, c=28.018(6) A, V=
29746(8) A , Z = 18, Fcalcd = 0.979 g cm-3, crystal dimensions
3
˚
0.24 ꢀ 0.28 ꢀ 0.29 mm3; Mo KR radiation, 298(2) K; 4417
reflections, 4471 independent (μ=0.149 mm-1); refinement (on
F2), 635 parameters, 0 restraints, R1= 0.1071 (I>2σ) and wR2
(all data) = 0.2786, GOF = 1.122, max./min. residual electron
-3
˚
density 0.476/-0.433 e A
.
X-ray crystal structure data for 2 Cl- 2CH2Cl2 (H2O):
˚
C65H55PdCl6N3OP4. triclinic, space group P1, a = 12.5610(3) A,
3
3
3
˚
˚
b = 15.5230(4) A, c = 16.3090(5) A, R = 94.3130(14)°, β =
3
˚
91.6340(14)°, γ=99.015(2)°, V=3129.20(16) A , Z=2, Fcalcd
=
1.419 g cm-3, crystal dimensions 0.22 ꢀ 0.26 ꢀ 0.28 mm3; Mo
KR radiation, 298(2) K; 27 53 reflections, 9845 independent (μ=
0.699 mm-1); refinement (on F2), 724 parameters, 0 restraints,
R1= 0.0827 (I > 2σ) and wR2 (all data)=0.2629, GOF=1.101,
1H NMR (toluene-d8): δ 1.60 (s, 9H), 6.69 (d, J = 8.4, 6H),
6.79 (m, 3H), 6.84 (m, 3H), 6.97-7.10 (m, 15H), 7.20 (m, 3H),
7.34 (m, 6H), 7.50 (m, 6H). 13C NMR (CDCl3): δ 10.1 (s, CH3),
113.6 (s, CH, indoly1), 120.3 (s, CH, indolyl), 122.0 (s, CH,
indolyl), 125.1 (s, CH, indolyl), 126-140. 31P NMR (CDCl3): δ
0
-3
˚
max./min. residual electron density 2.177/-0.745 e A
.
X-ray Crystal Structure Data for 3 CH2Cl2. C64H53Rh-
˚
Cl3N3P4. monoclinic, space group P2(1)/c, a = 12.2170(2) A,
3
˚
˚
5.0 (dd, JP-Rh=138.4 Hz, JP-P =30.4 Hz), 131.3 (dq, JP-Rh
=
b = 18.7130(3) A, c = 25.2030(5) A, β = 97.0640(7)°, V =
168.2 Hz, JP-P = 30.4P). MS (FABþ): m/z (%) 1112 (100),
[M]þ; 1076 (16), [M - Cl]þ. Anal. Found: C 67.27, H 4.59,
N 3.93. Calcd for C63H51ClN3P4Rh: C 68.02, H 4.62, N 3.78.
Crystallographic data were collected on a Kappa CCD
diffractometer for compounds 1 and 2 and on a Kappa 2000
for compound 3. The structures were solved by direct methods
and refined using the SHELXTL15 program. Non-hydrogen
atoms were refined with anisotropic displacement parameters.
Hydrogen atoms were added in calculated positions. The
H atoms of the water molecule on compound 2 could not be
located. In compound 1 the solvent molecules could not be
modeled properly, due to the low crystal quality. The program
SQUEEZE, part of the PLATON package of crystallographic
software, was used to calculate the solvent disorder area and
5718.09(17) A , Z=4, Fcalcd=1.391 g cm-3, crystal dimensions
3
˚
0
0.25 ꢀ 0.29 ꢀ 0.32 mm3; Cu KR radiation, 298(2) K; 15 747
reflections, 6853 independent (μ=5.096 mm-1); refinement (on
F2), 680 parameters, 0 restraints, R1 = 0.0736 (I>2σ) and wR2
(all data) = 0.2141, GOF = 1.037, max./min. residual electron
-3
˚
density 0.888/-1.310 e A
.
Acknowledgment. This work was supported by the
Spanish Ministry of Science and Technology [CTQ2005-
06909-C02-01/BQU and CTQ2008-06466].
Supporting Information Available: NMR spectra of com-
pounds 1-3. This material is available free of charge via the
Internet at http://pubs.acs.org.
(15) Sheldrick, G. M. SHELXTL 6.1; Bruker AXS, Inc.: Madison, WI,
2001.
(16) Spek, A. L. PLATON; Utrecht University: Utrecht, The Netherlands,
2005.