New bis-biphosphole - transition-metal complexes: Spontaneous isomerization of trans-meso- into cis-±[Ru(trifluoroacetate)2(1,1′- diphenyl-3,3′,4,4′-tetramethyl-2,2′-biphosphole)2]

Article abstract of DOI:10.1021/om980667i

The reaction of [Ru₂(O₂CCF₃) ₂(μ-O₂CCF₃)₂-(COD) ₂(μ-H₂O)] with 1,1′-diphenyl-3,3′,4, 4′-tetramethyl-2,2′-biphosphole (1) provides trans-meso- [Ru(trifluoroa

Full text of DOI:10.1021/om980667i

Organometallics 1998, 17, 5927-5930
5927
New Bis-bip h osp h ole-Tr a n sition -Meta l Com p lexes:
Sp on ta n eou s Isom er iza tion of tr a n s-m eso- in to
cis-(()-[Ru (tr iflu or oa ceta te)2(1,1′-d ip h en yl-3,3′,4,4′-
tetr a m eth yl-2,2′-bip h osp h ole)2]
Olivier Tissot, Maryse Gouygou,*,† J ean-Claude Daran, and
Gilbert G. A. Balavoine*,‡
Laboratoire de Chimie de Coordination du CNRS, 205 Route de Narbonne,
31077 Toulouse Cedex, France
Received August 3, 1998
Summary: The reaction of [Ru2(O2CCF3)2(µ-O2CCF3)2-
(COD)2(µ-H2O)] with 1,1′-diphenyl-3,3′,4,4′-tetramethyl-
2,2′-biphosphole (1) provides trans-meso-[Ru(trifluoro-
a ceta te)2 (1,1′-d iph en yl-3,3′,4,4′-tetr a m eth yl-2,2′-
biphosphole)2] complex 3, which spontaneously isomerizes
in solution into cis-(()-[Ru(trifluoroacetate)2(1,1′-diphe-
nyl-3,3′,4,4′-tetramethyl-2,2′-biphosphole)2] complex 4.
These new bis-biphosphole-ruthenium complexes have
been characterized by X-ray diffraction.
The structural characterization of 1,1′-diphenyl-
3,3′,4,4′-tetramethyl-2,2′-biphosphole1 (1) (BIPHOS) led
to a renewed interest in the coordination chemistry of
this C2-symmetric bidentate ligand, first described by
Mathey.2 Recently, we have synthesized and fully
characterized new nickel, palladium, and platinum
complexes [MX2(BIPHOS)].3 With Pd(II) and Rh(I), we
obtained the first bis-biphosphole complexes,3 proving
that BIPHOS is a rather good ligand for transition
metals. A similar palladium complex was later described
by Matsuda and co-workers.4 We report here the syn-
thesis, spectroscopic characterization and X-ray struc-
tural analysis of new ruthenium(II) bis-biphosphole
complexes.
F igu r e 1. Molecular view of complex 3. The ellipsoids are
drawn at 30% probability. Phenyl carbons are omitted for
clarity.
Sch em e 1
[Ru2(O2CCF3)2(µ-O2CCF3)2(COD)2(µ-H2O)]5 (2) is a
good precursor for the preparation of diphosphine di-
carboxylato ruthenium complexes [Ru(O2CCF3)2(P-P)].6
Surprisingly, the reaction of biphosphole 1, prepared
according to the previously described method,7 with
complex 2 in dichloromethane at 30 °C gives in moder-
ate yield a bis-biphosphole-ruthenium complex 3
(Scheme 1), as indicated by elemental analysis and mass
spectroscopy. Crystals of complex 3, suitable for X-ray
analysis, were obtained by slow evaporation from a
dichloromethane solution.
octahedral geometry for ruthenium and mutually trans-
ligated monodentate trifluoroacetate groups. X-ray struc-
tural analysis confirms the formation of [Ru(O2CCF3)2-
(BIPHOS)2] as complex 3. This complex contains the SRR
and RSS absolute configurations of the biphosphole 1
(Figure 2), and it is then the meso diastereomer as
already observed in the [Pd(BIPHOS)2](BF4)2 complex.3
Surprisingly this compound 3 crystallized in the polar
enantiomorphous P21 space group. This non-centrosym-
metry might be induced by the packing arrangement
of the complex with the occurrence of four solvent
molecules. Indeed, it is worth noting that crystals of the
The CAMERON8 plot given in Figure 1 shows a near-
† E-mail: gouygou@lcc-toulouse.fr.
‡ E-mail: balavoin@lcc-toulouse.fr.
(1) Tissot, O.; Gouygou, M.; Daran, J .-C.; Balavoine, G. G. A. J .
Chem. Soc., Chem. Commun. 1996, 2288.
(2) Mercier, F.; Holand, S.; F. Mathey, F. J Organomet Chem. 1986,
316, 271.
(3) Gouygou, M.; Tissot, O.; Daran, J .-C.; Balavoine, G. G. A.
Organometallics 1997, 5, 1008.
(4) Kojima, T. K.; Saeki, K.; Ono, K.; Ohda, M.; Matsuda, Y. J . Chem.
Soc., Chem. Commun. 1997, 1679; 1998, 521.
(5) Albers, M. O.; Liles, D. C.; Singleton, E.; Yates, J . E. J Organomet
Chem. 1984, 272, C62.
(6) Heiser, B.; Broger, E. A.; Crameri, Y. Tetrahedron: Asymmetry
1991, 2, 51.
(7) Deschamps, E.; Mathey, F. Bull. Soc. Chim. Fr. 1992, 29, 486.
(8) Watkin, D. J .; Prout, C. K.; Pearce, L. J . CAMERON; Chemical
Crystallography Laboratory, University of Oxford: Oxford, 1996.
10.1021/om980667i CCC: $15.00 © 1998 American Chemical Society
Publication on Web 12/01/1998

5928 Organometallics, Vol. 17, No. 26, 1998
Notes
F igu r e 2. Configuration of the 2,2′-biphosphole ligand in
complex 3. The projection is along the axis of the C-C bond
linking the phosphole rings. Superscript refers to axial
chirality generated by the biphosphole framework; sub-
script refers to phosphorus central chirality.
Ta ble 1. Selected Bon d Len gth s (Å) a n d Bon d
An gles (d eg) w ith esd ’s in P a r en th eses for
Com p ou n d s 3 a n d 3′
F igu r e 3. Molecular view of complex 4. The ellipsoids are
drawn at 30% probability.
molecule 3
molecule 3′
Ta ble 2. Selected Bon d Len gth s (Å) a n d Bon d
An gles (d eg) w ith esd ’s in P a r en th eses for
Com p ou n d s 4
Ru(1)-P(1)
2.359(1)
2.388(1)
2.379(1)
2.396(1)
2.125(3)
2.129(3)
Ru(1)-P(1)
2.358(4)
2.392(4)
2.372(4)
2.375(3)
2.106(9)
2.112(8)
Ru(1)-P(2)
Ru(1)-P(5)
Ru(1)-P(4)
Ru(1)-O(1)
Ru(1)-O(3)
Ru(1)-P(2)
Ru(1)-P(5)
Ru(1)-P(4)
Ru(1)-O(1)
Ru(1)-O(3)
Ru(1)-P(1)
Ru(1)-P(4)
Ru(1)-O(1)
2.358(4)
2.275(3)
2.173(9)
Ru(1)-P(2)
Ru(1)-P(5)
Ru(1)-O(3)
2.296(4)
2.394(4)
2.130(9)
P(4)-Ru(1)-P(2)
P(4)-Ru(1)-P(1)
P(2)-Ru(1)-P(1)
O(3)-Ru(1)-P(5)
O(1)-Ru(1)-P(5)
P(4)-Ru(1)-P(5)
P(2)-Ru(1)-P(5)
P(1)-Ru(1)-P(5)
94.2(1)
88.6(1)
84.3(1)
82.8(2)
95.0(3)
84.2(1)
98.6(1)
172.4(1)
O(3)-Ru(1)-O(1)
O(3)-Ru(1)-P(4)
O(1)-Ru(1)-P(4)
O(3)-Ru(1)-P(2)
O(1)-Ru(1)-P(2)
O(3)-Ru(1)-P(1)
O(1)-Ru(1)-P(1)
82.8(3)
95.9(2)
178.6(3)
169.9(2)
87.1(2)
95.6(2)
92.1(3)
P(1)-Ru(1)-P(2)
P(1)-Ru(1)-P(5)
P(2)-Ru(1)-P(5)
P(1)-Ru(1)-P(4)
P(2)-Ru(1)-P(4)
P(5)-Ru(1)-P(4)
P(1)-Ru(1)-O(1)
P(2)-Ru(1)-O(1)
P(5)-Ru(1)-O(1)
P(4)-Ru(1)-O(1)
P(1)-Ru(1)-O(3)
P(2)-Ru(1)-O(3)
P(5)-Ru(1)-O(3)
P(4)-Ru(1)-O(3)
O(1)-Ru(1)-O(3)
83.75(5)
179.17(6)
97.06(5)
95.38(5)
178.89(6)
83.80(5)
83.3(1)
81.8(1)
96.7(1)
97.5(1)
96.4(1)
P(1)-Ru(1)-P(2)
P(1)-Ru(1)-P(5)
P(2)-Ru(1)-P(5)
P(1)-Ru(1)-P(4)
P(2)-Ru(1)-P(4)
P(5)-Ru(1)-P(4)
P(1)-Ru(1)-O(1)
P(2)-Ru(1)-O(1)
P(5)-Ru(1)-O(1)
P(4)-Ru(1)-O(1)
P(1)-Ru(1)-O(3)
P(2)-Ru(1)-O(3)
P(5)-Ru(1)-O(3)
P(4)-Ru(1)-O(3)
O(1)-Ru(1)-O(3)
83.4(1)
178.7(1)
97.3(1)
95.8(1)
179.1(1)
83.5(1)
84.8(3)
82.5(3)
96.3(3)
96.9(3)
95.7(3)
98.2(2)
83.1(3)
82.5(2)
179.2(3)
palladium complex [Pd(BIPHOS)2](BF4)2.3 Transforma-
tion of complex 3 was observed in solution, leading to
the formation of a new complex 4 (Scheme 1). By
following the course of this conversion by 31P NMR
spectroscopy, we observed the disappearance of the
singlet at δ ) 54.5 corresponding to four equivalent
phosphorus nuclei in complex 3 concomitant with the
appearance of an ABCD system corresponding to four
nonequivalent phosphorus nuclei in complex 4. Elemen-
97.5(1)
83.7(1)
83.3(1)
179.2(2)
same meso form having only two CH2Cl2 solvent mol-
ecules, compound 3′, belong to the centrosymmetric
space group P21/c. Although unexpected, the monoden-
tate coordination mode of the trifluoroacetate groups is
not unprecedented, and there are many examples of a
such bonding mode for the trifluoroacetate.9 The four
Ru-P bond distances lie in the range 2.32-2.42 Å found
for related ruthenium(II) bisphosphine trans-disubsti-
tuted complexes10 (cf. Table 1).
1
tal analysis, mass spectroscopy, and H NMR spectros-
copy confirmed the formation of a bis-biphosphole-
ruthenium complex 4. The molecular structure deter-
mined by X-ray analysis and represented in Figure 3
shows a chiral near-octahedral geometry for ruthenium.
As in 3, this complex 4 contains the pair of enantiomers
of biphosphole 1 with SRR and RSS absolute configura-
tions but with two cis monodentate trifluoroacetate
groups leading to a chiral arrangement around the
metal atom. The two Ru-P bond lengths corresponding
to the P atoms trans to each other, 2.358(4) and 2.394-
(4) Å, are similar to those observed for 3, whereas for
the two P atoms trans to the trifluoroacetate the Ru-P
distances are much shorter, 2.275(3) and 2.296(4) Å, as
also observed in related complexes11 (cf. Table 2). This
large difference could be the consequence of a strong
trans influence of the trifluoroacetate ligands. We
assume that the formation of the kinetic product 3 is
This meso-Ru complex 3 is stereochemically less
stable in dichloromethane solution than the meso-
(9) (a) Fachinetti, G.; Funaioli, T.; Lecci, L.; Marchetti, F. Inorg.
Chem. 1996, 35, 7217; (b) Wong, W.-K.; Lai, K.-K.; Tse, M.-S.; Tse,
M.-C.; Gao, J .-X.; Wong, W.-T.; Chan, S. Polyhedron 1994, 13, 2751;
(c) Nishiyama, H.; Itoh, Y.; Sugawara, Y.; Matsumoto, H.; Aoki, K.;
Itoh, K. Bull. Chem. Soc. J pn. 1995, 68, 1247; (d) Zanetti, N. C.;
Spindler, F.; Spencer, J .; Togni, A.; Rihs, G. Organometallics 1996,
15, 860.
(10) (a)Touchard, D.; Morice, C.; Cadierno, V.; Haquette, P.; Toupet,
L.; Dixneuf, P. H. J . Chem. Soc., Chem. Commun. 1994, 859. (b) Field,
L. D.; Hambley, T. W.; Yau, B. C. K. Inorg. Chem. 1994, 33, 2009. (c)
Hockless, D. C. R.; Wild, S. B.; McDonagh, A. M.; Whittall, I. R.;
Humphrey, M. G. Acta Crystallogr., Sect. C 1996, 52, 1639. (d)
Faulkner, C. W.; Ingham, S. L.; Khan, M. S.; Lewis, J .; Long, N. J .;
Raithby, P. R. J . Organomet. Chem. 1994, 482, 139. (e) Buys, I. E.;
Field, L. D.; George, A. V.; Hambley, T. W.; Purches, G. R. Aust. J .
Chem. 1995, 48, 27. (f) Szczepura, L. F.; Giambra, J .; See, R. F.;
Lawson, H.; J anik, T. S.; J ircitano, A. J .; Churchill, M. R.; Takeuchi,
K. J . Inorg. Chim. Acta 1995, 239, 77.
(11) (a) Dobson, A.; Moore, D. S.; Robinson, S. D.; Hurthouse, M.
B.; New, L. Polyhedron 1985, 4, 1119. (b) Albers, M. O.; Liles, D. C.;
Singleton, E. Acta Crystallogr., Sect. C 1987, 43, 860.

Notes
Organometallics, Vol. 17, No. 26, 1998 5929
Ta ble 3. Cr ysta l Da ta
3
3′
4
formula
C
52H48F6O4P4Ru,
C52H48F6O4P4Ru,
(CH2Cl2)2
1245.8
C52H48F6O4P4Ru,
C5H12, CH3CO2C2
1155.98
(CH2Cl2)4
1415.6
fw
cryst size, mm
cryst system
space gp
a, Å
0.58 × 0.45 × 0.30
monoclinic
P21
11.120(2)
23.012(3)
12.145(2)
96.38(2)
3088.6(8)
2
0.8 × 0.3 × 0.3
monoclinic
P21/c
0.38 × 0.08 × 0.05
orthorhombic
Pcab
22.416(5)
11.144(2)
22.628(2)
104.58(2)
5493(8)
20.652(2)
b, Å
21.906(3)
24.229(3)
c, Å
â, deg
V, Å3
10961(2)
8
1.401
4.70
33 608
5777(0.212)
full-matrix on F2
5777/0/644
0.0847
Z
4
D
calcd, g cm-3
1.522
7.650
17 973
1.501
µ(Mo KR), cm-1
6.511
no. of rflns collected
no. of unique rflns (Rint
refinement method
3937
)
9373(0.055)
full-matrix on F
8095/0/714
0.0476
3789(0.026)
full-matrix on F
2343/0/389
0.0676
no. of data/restraints/params
R (I > 2σ(I))a
a
Rw
0.0555
0.0796
wR2 (all data)a
goodness of fit
0.1749
1.068
1.070
1.170
a
2
R ) ∑(||Fo| - |Fc||)/∑(|Fo|), Rw ) {∑[w(|Fo| - |Fc|)]2/∑[w(Fo)2}1/2, wR2 ) {∑[w(Fo - Fc2)2]/∑[w(Fo)2]}1/2
.
12,52,42), 138.89 (t, J CP 19.0 Hz, C1,11,41,51), 128.12 (t, J CP
20.8 Hz, C4,14,44,54), 112.29 (q, J CF 293.4 Hz, O2CCF3), 17.37
(t, J CP 2.5 Hz, C31,131,431,531), 15.02 (t, J CP 1.7 Hz, C21,-
121,421,521).
probably controlled by steric factors. Indeed, the mo-
lecular structures reveal that steric constraints between
the two enantiomers of 1 seem to be lower in the trans-
meso-3 than in the cis-(()-4. On the other hand, we
assume that the isomerization of the trans-meso-3 into
the thermodynamic product cis-(()-4 is triggered by the
trans influence of the monodentate trifluoroacetate
ligands. We may consider that this trans influence
facilitates a decoordination-recoordination process of
one of the trifluoroacetate ligands eventually assisted
by the formation of an intermediate with a trihapto
coordination of the other.
Syn th esis of [Ru (O2CCF 3)2(BIP HOS)2], 4. Complex 4 was
quantitatively obtained by slow evolution of 3 in a dichlorome-
tane solution within 8 days at room temperature. 4 crystallizes
from an ethyl acetate solution by slow diffusion with pentane
as yellow plates. Mp: 203 °C (decomp). Anal. Calcd for
C52H48P4O4F6Ru: C, 58.05; H, 4.49. Found: C, 58.35; H, 4.54.
MS (FAB, MNBA matrix), m/z: 963 ([M - O2CCF3]+, 100); 849
([M - 2(O2CCF3)]+, 44). 1H NMR (CD2Cl2 ): δ 1.38 (s, 3H),
1.91 (s, 3H), 2.11 (s, 3H), 2.32 (s, 3H) [Me21,121,321,421], 1.66
(s, br, 3H), 1.70 (d,4J HH 1.8 Hz, 3H), 1.90 (s, br, 3H), 2.16 (d,
2
4J HH 2.7 Hz, 3H) [Me31,131,321,421], 5.61 (d, J HP 28.9 Hz,
Exp er im en ta l Section
1H), 6.17 (d, 2J HP 28.8 Hz, 1H), 6.71 (d, 2J HP 27.3 Hz, 1H), 7.03
2
(d, J HP 21.1 Hz, 1H) [dCH-P], 6.23-8.05 (m, 20H, Ph). 31P-
Gen er a l P r oced u r es. All reactions were conducted under
an inert atmosphere of dry argon by using Schlenk glassware
and vacuum line techniques. Solvents were freshly distilled
from standard drying agents.
{1H} NMR (CD2Cl2 ): δ 63.35 (m, PA, PB), 54.11 (m, PC), 44.78
(m, PD). 13C{1H} NMR (CD2Cl2 ): δ 153.23 (d, J CP 8.7 Hz),
152.00 (m), 150.39 (m), 149.32 (m) [C3,13,43,53], 146.94 (t, J CP
12.7 Hz), 142.47 (t, J CP 13.0 Hz), 137.54 (s, br), 136.72 (d, J CP
13.7 Hz) [C2,12,52,42], 145,12 (m), 140.13 (m), 139.69 (m),
137.16 (m) [C1,11,41,51], 133.92 (d, J CP 39.5 Hz), 132.05 (m),
127.04 (d, J CP 38.0 Hz), 121.25 (d, J CP 46.0 Hz) [C4,14,44,54],
18.44 (d, J CP 5.0 Hz), 17.53 (d, J CP 10.8 Hz), 17.1 (d, J CP 10.2
Hz), 16.96 (d, J CP 9.7 Hz) [C31,131,431,531], 15.37 (d, J CP 6.9
Hz), 15.21 (d, J CP 7.1 Hz), 14.60 (d, J CP 7.9 Hz), 14.40 (d, J CP
9.6 Hz) [C21,121,421,521].
1H, 13C{1H, 31P}, and 31P{1H} NMR spectra were recorded
on the Bruker WMX 400 instrument operating at 400, 162,
and 100 MHz, respectively. Chemical shifts are reported in
parts per million (ppm) relative to Me4Si (1H and13C) or 85%
H3PO4 (31P).
Elemental analyses were performed by the “Service d’Analyse
du Laboratoire de Chimie de Coordination” at Toulouse,
France.
Mass spectra were obtained on a Mermag R10-10 instru-
ment.
X-r a y Str u ctu r e Deter m in a tion . For 3 and 4, the data
were collected on a Stoe IPDS (Imaging Plate Diffraction
System) equipped with an Oxford Cryosystems cooler device,
whereas for 3′ an Enraf-Nonius CAD4F was used. The final
unit cell parameters were obtained by the least-squares
refinement of 5000 reflections for 3 and 4 and based on 25
well-centered reflections for 3′. Only statistical fluctuations
were observed in the intensity monitors over the course of the
data collection for 3 and 4, but a decrease of 44% was observed
in the case of 3′.
The three structures were solved by direct methods (SIR92)12
and refined by least-squares procedures. H atoms were
introduced in calculation in idealized positions (d(CH) ) 0.96
Å) and were treated as riding models with isotropic thermal
parameters 20% higher than those of the carbon to which they
Syn th esis of [Ru (O2CCF 3)2(BIP HOS)2], 3. To a solution
of 31 mg of [Ru2(O2CCF3)2(µ-O2CCF3)2(COD)2(µ-H2O) ] (0.033
mmol) in 2 mL of dichloromethane was added a solution of 52
mg of biphosphole 1 (0.13 mmol, 4 equiv) in 1 mL of dichlo-
romethane. The yellow mixture was stirred for 3 h at 30 °C.
After removal of the solvent the resulting orange solid was
washed two times with 1 mL of diethyl ether at 0 °C and then
dried in vacuo. Orange blocks of 3 were isolated after crystal-
lization in a CH2Cl2 solution. Yield: 30 mg (40%). Mp: 197 °C
(decomp). Anal. Calcd for C52H48P4O4F6Ru: C, 58.05; H, 4.49.
Found: C, 57.86; H, 4.28. MS (FAB, MNBA matrix), m/z: 1077
(M+, 27); 963 ([M - O2CCF3]+, 100); 849 ([M - 2(O2CCF3)]+,
56). 1H NMR (CD2Cl2 ): δ 1.99 (s, 12H, Me21,121,321,421),
4
2.08 (d, 12H, J HH 1.0 Hz, Me31,131,321,421), 6.79 (m, 4H,
(12) Altomare, A.; Cascarano, G.; Giacovazzo, G.; Guagliardi, A.;
Burla, M. C.; Polidori, G.; Camalli, M. SIR92-a program for automatic
solution of crystal structures by direct methods. J Appl. Crystallogr.
1994, 27, 435.
dCH-P), 6.91-7.15 (m, 20H, Ph). 31P{1H} NMR (CD2Cl2 ): δ
2
54.5. 13C{1H} NMR (CD2Cl2 ): δ 161.11 (q, J CF 38.2 Hz,
O2CCF3), 151.74 (s, C3,13,43,53), 142.43 (t, J CP 6.9 Hz, C2,-

5930 Organometallics, Vol. 17, No. 26, 1998
Notes
are attached. Details of data collections and refinements are
given in Table 3. In crystal 4, there is apparently a disordered
mixture of pentane and ethyl acetate solvents statistically
distributed around inversion centers; however no correct
models could be defined and all the residual electron densities
were considered as C atoms. The calculations were carried out
with the CRYSTALS package13 or the SHELXL97 program14
running on a PC. The drawing of the molecule was realized
with the help of CAMERON.8
Selected bond lengths and bond angles are given in Tables
1 and 2.
Ack n ow led gm en t. We acknowledge the CNRS and
Rhoˆne-Poulenc for financial support and Professor F.
Mathey for advice and fruitful discussions.
Su ppor tin g In for m ation Available: The fractional atomic
coordinates, full bond lengths and bond angles, anisotropic
thermal parameters, and atomic coordinates for H atoms for
3, 3′, and 4 (20 pages). Ordering information is given on any
current masthead page. This information has also been
deposited at the Cambridge Crystallographic Data Centre.
(13) Watkin, D. J .; Prout, C. K.; Carruthers, J . R.; Betteridge, P.
W. CRYSTALS Issue 10; Chemical Crystallography Laboratory, Uni-
versity of Oxford: Oxford, 1996.
(14) Sheldrick, G. M. SHELXL-97, program for crystal structure
refinement; University of Go¨ttingen, 1997.
OM980667I