[μ-1κ2O,O′:2(η5)-cyclopentadienylc arboxylato][2(η5)-diphenylphosphinocyclopentadienyl]bis[1,1(η 5)-tetramethylcyclopentadienyl]iron(II)titanium(III)

Article abstract of DOI:10.1107/S0108270101019370

A novel paramagnetic titanocene-ferrocene complex was produced and characterized by spectral methods. The crystal structure of the compound was also determined. The arrangement of the carboxylate moiety in the compound was similar to the titanocene comple

Full text of DOI:10.1107/S0108270101019370

metal-organic compounds
[Ti(ꢀ5-C5R5)2(ꢀ2-Me3SiC CSiMe3)] (R is H or Me), which
behave as a source of reactive titanocenes, [Ti(ꢀ5-C5R5)2]
(Varga et al., 1996). The reaction of [Ti(ꢀ5-C5HMe4)2-
(ꢀ2-Me3SiC CSiMe3)] with one molar equivalent of Hdpf
Acta Crystallographica Section C
Crystal Structure
Communications
ISSN 0108-2701
produced
a
novel paramagnetic titanocene±ferrocene
complex, namely the title compound, (I), in high yield. The
title complex has been characterized by spectral methods and
its structure determined. The results are presented here.
[l-1j2O,O0:2(g5)-Cyclopentadienyl-
carboxylato][2(g5)-diphenylphos-
phinocyclopentadienyl]bis[1,1(g5)-
tetramethylcyclopentadienyl]iron(II)-
titanium(III)
a
a
Âb
Ï
Ï
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Â
Â
Karel Mach, Jirõ Kubista, Ivana Cõsarova and Petr
b
Æ
Ï
Ï
Stepnicka *
a
Â
J. Heyrovsky Institute of Physical Chemistry, Academy of Sciences of the Czech
Republic, Dolejskova 3, 182 23 Prague 8, Czech Republic, and bDepartment of
Ï
The molecular structure is shown in Fig. 1 and selected
geometric parameters are given in Table 1. Both metallocene
units exhibit the expected arrangement. The titanocene
moiety is bent, with a dihedral angle between the least-squares
cyclopentadienyl planes Cp3 and Cp4 of 46.24 (5)ꢀ, and is very
nearly bisected by the TiO2 plane [angle between Cp3 and
TiO2 22.88 (4), and between Cp4 and TiO2 23.46 (5)ꢀ]. The
planes are de®ned as follows: Cp1 = C1±C5, Cp2 = C6±C10,
Cp3 = C30±C34, Cp4 = C40±C44, Ph1 = C12±C17, Ph2 = C18±
C23, TiO2 = Ti/O1/O2 and CO2 = C11/O1/O2. Cg denotes the
ring centroid of the corresponding least-squares cyclopenta-
dienyl plane. The Cg3ÐTiÐCg4 angle is 137.09 (4)ꢀ; the TiÐ
Inorganic Chemistry, Charles University, Hlavova 2030, 128 40 Prague 2, Czech
Republic
Correspondence e-mail: stepnic@mail.natur.cuni.cz
Received 2 November 2001
Accepted 13 November 2001
Online 23 January 2002
Reacting stoichiometric amounts of 1-(diphenylphosphino)-
ferrocenecarboxylic acid and [Ti(ꢀ5-C5HMe4)2(ꢀ2-Me3SiC C-
SiMe3)] produced the title carboxylatotitanocene complex,
[{ꢁ-1ꢂ2O,O0:2(ꢀ5)-C5H4CO2}{2(ꢀ5)-C5H4P(C6H5)2}{1(ꢀ5)-C5H-
(CH3)4}2FeIITiIII] or [FeTi(C9H13)2(C6H4O2)(C17H14P)]. The
angle subtended by the Ti/O/O0 plane, where O and O0 are
the donor atoms of the ꢂ2-carboxylate group, and the plane of
the carboxyl-substituted ferrocene cyclopentadienyl is
24.93 (6)ꢀ.
Ê
Cg distances differ only slightly: TiÐCg3 = 2.0513 (8) A and
Ê
TiÐCg4 = 2.0567 (8) A. The titanocene cyclopentadienyls are
staggered [ꢃ(C30ÐCg3ÐCg4ÐC40) = 39.1 (1)ꢀ; ideal value =
36ꢀ], with the non-substituted ring C atoms located at the
hinge position. The methyl substituents are disposed from the
cyclopentadienyl planes outwards from the Ti centre, the
Ê
maximum perpendicular distance being 0.100 (3) A for atom
C45 and the Cp4 plane.
Comment
Multidentate ligands possessing donor groups of different
natures according to Pearson's hard and soft acid and base
concept (so-called hybrid ligands) are capable of hemilabile
coordination and of linking (different) transition metals into
multinuclear complexes. Whereas the former property plays
an important role in homogeneous catalysis, the latter is
relevant mainly to fundamental research and material chem-
istry.
We have recently reported the synthesis of a ferrocene
carboxyphosphine ligand, 1-(diphenylphosphino)ferrocene-
carboxylic acid (Hdpf; Podlaha et al., 1995), and its coordi-
Æ
Ï
Ï
nation properties towards various metals (Stepnicka et al.,
1999; Pinkas et al., 2001). In order to obtain novel titanocene±
ferrocene complexes, which to date are represented mostly by
compounds having the metallocene units directly connected or
Figure 1
A view of the molecular structure of (I). Displacement ellipsoids are
drawn at the 30% probability level. For clarity, H atoms have been
omitted.
Æ
Ï
Ï
separated by hydrocarbon bridges (Stepnicka et al., 2000), we
have studied the reactivity of Hdpf towards TiII complexes
m116 # 2002 International Union of Crystallography
DOI: 10.1107/S0108270101019370
Acta Cryst. (2002). C58, m116±m118

metal-organic compounds
Table 1
Selected geometric parameters (A, ).
The cyclopentadienyl rings of the bridging ferrocene unit
are nearly parallel [Cp1/Cp2 = 1.1 (1)ꢀ] and, as indicated by
the torsion angle ꢃ(C1ÐCg1ÐCg2ÐC6) of 163.4 (1)ꢀ, adopt
a conformation halfway between anticlinal eclipsed (ꢃ = 144ꢀ)
and antiperiplanar staggered (ꢃ = 180ꢀ). The distances of the
Fe atom to the cyclopentadienyl ring centroids, FeÐCg1 =
ꢀ
Ê
FeÐC1
FeÐC2
FeÐC3
FeÐC4
FeÐC5
FeÐC6
FeÐC7
FeÐC8
FeÐC9
FeÐC10
TiÐO1
TiÐO2
TiÐC30
TiÐC31
2.0409 (15)
2.0566 (17)
2.0569 (17)
2.0478 (17)
2.0360 (17)
2.0435 (16)
2.0380 (17)
2.0484 (17)
2.0512 (17)
2.0457 (16)
2.1582 (12)
2.1658 (11)
2.3489 (16)
2.3435 (16)
TiÐC32
TiÐC33
TiÐC34
TiÐC40
TiÐC41
TiÐC42
TiÐC43
TiÐC44
PÐC6
PÐC12
PÐC18
O1ÐC11
O2ÐC11
C1ÐC11
2.3718 (16)
2.4166 (16)
2.4095 (17)
2.3256 (16)
2.3771 (16)
2.4440 (16)
2.4189 (16)
2.3493 (16)
1.8122 (17)
1.8359 (18)
1.8349 (17)
1.2697 (19)
1.2693 (19)
1.474 (2)
Ê
1.6513 (8) and FeÐCg2 = 1.6476 (8) A, correspond well to the
FeÐCg distances in uncoordinated Hdpf (Podlaha et al.,
1995). Likewise, the arrangement at the phosphino substi-
tuent, which remains unaffected by coordination, resembles
that of Hdpf [dihedral angles: Ph1/Ph2 = 82.85 (5)ꢀ, Cp2/Ph1 =
75.31 (6)ꢀ and Cp2 = Ph2 84.06 (6)ꢀ].
The two metallocene units are mutually rotated, as de®ned
by the dihedral angle of 24.93 (6)ꢀ between the Cp1 and TiO2
planes. Although the pseudo-tetrahedral arrangement
around the Ti atom is severely distorted due to the steric
requirements of the carboxylate and cyclopentadienyl
ligands [O1ÐTiÐO2 = 60.85 (4)ꢀ and Cg3ÐTiÐCg4 =
46.24 (5)ꢀ], the carboxylate ligand is bonded in a symmetric
O1ÐTiÐO2
C6ÐPÐC12
C6ÐPÐC18
C12ÐPÐC18
C11ÐO1ÐTi
60.85 (4)
100.71 (8)
100.52 (8)
101.96 (8)
89.68 (9)
C11ÐO2ÐTi
O2ÐC11ÐO1
O2ÐC11ÐC1
O1ÐC11ÐC1
89.35 (9)
119.18 (14)
121.10 (14)
119.59 (14)
TiÐO1ÐC11ÐC1
TiÐO2ÐC11ÐC1
166.29 (13)
166.26 (13)
C2ÐC1ÐC11ÐO1
C5ÐC1ÐC11ÐO2
19.0 (2)
17.7 (2)
Ê
fashion. The TiÐO bond lengths differ by only 0.014 A, whilst
the lengths of the carboxylic CÐO bonds are identical within
the precision of measurement. The four-membered Ti/O1/O2/
C11 ring is slightly bent along the O1Á Á ÁO2 diagonal, with the
Ê
Experimental
carboxylic C11 atom disposed by 0.124 (2) A from the TiO2
plane, though without deformation of the planar arrangement
at C11, as evidenced by the sum of the bond angles being
359.9ꢀ.
The arrangement of the carboxylate moiety is similar to the
titanocene complex with chelating benzoate, [Ti(ꢀ5-
C5H5)2(PhCO2-ꢂ2O,O0)] (Clauss et al., 1983), which exhibits
TiÐO bond lengths of 2.134 (3), 2.147 (3), 2.152 (4) and
On a vacuum line, a solution of Hdpf (207 mg, 0.50 mmol) in toluene
(20 ml) was added to solid [Ti(ꢀ5-C5HMe4)2(ꢀ2-Me3SiC CSiMe3)]
(235 mg, 0.51 mmol; Varga et al., 1996) and the resulting green±brown
solution was heated to 333 K for 1 h. All volatiles were then removed
under vacuum and the residue was extracted with hexane (50 ml).
The extracts were concentrated to crystallization and kept at 273 K
overnight to afford compound (I) as thin brown crystals. The mother
liquor was concentrated and crystallized as above to provide an
additional crop of crystals (combined yield: 307 mg, 84%; m.p.
398 K). Spectroscopic analysis: electron-spin resonance (toluene,
295 K): g = 1.9793, H = 3.0 G, aTi = 7.3 G; IR (KBr, cm 1): 3068 (w),
3050 (w), 2943 (m), 2907 (s), 2858 (m), 1585 (m), 1506 (s) [ꢅas(CO2)],
1434 (m), 1396 (s) [ꢅs(CO2)], 1358 (m), 1190 (w), 1163 (m), 1092 (w),
1027 (s), 828 (s), 812 (s), 798 (m), 744 (s), 697 (s), 634 (m), 506 (m),
486 (w), 451 (m), 422 (m); MS [m/z (relative abundance)]: 706 (6),
705 (21), 704 (53), 703 (100, M+Á), 702 (18), 701 (17), 582 (4), 352 (7),
Ê
2.155 (3) A (two independent molecules), and CÐO distances
Ê
in the range 1.254 (6)±1.271 (5) A. As a comparison, the
monodentate phosphinocarboxylate in [Ti(ꢀ5-C5H5)2(Ph2P-
CH2CO2-ꢂO)2] (Edwards et al., 2000) shows similar TiÐO
Ê
bond lengths of 1.925 (5) and 1.972 (4) A, but clearly distinct
CÐO distances within the carboxylate moiety of 1.282 (8) and
Ê
Ê
1.300 (7) A for CÐO, and 1.189 (8) and 1.216 (6) A for C O.
The Cp1 and CO2 planes in (I) are rotated by as much as
19.3 (1)ꢀ from a coplanar arrangement, and the C1ÐC11 bond
is slightly shorter than the corresponding distance in Hdpf
305 (4), 292 (11), 290 (14), 289 {14, [(C5Me4H)2Ti
105 (7).
H]+}, 287 (4),
Ê
(1.452 and 1.458 A). Nevertheless, it is likely that conjugation
Crystal data
between the Cp1 ring and the carboxylate group remains
active, since it has been shown for ferrocenoyl derivatives of
the general formula [Fe(ꢀ5-C5H5)(ꢀ5-C5H4C(O)X)] (X is OH
or NH2) that the ꢄ systems interact even at Cp-to-COX twist
angles of 40±50ꢀ (Lin et al., 1998). Hence, the rotation as well
as the bending of the Ti/O1/O2/C11 ring can be ascribed to
inter- and intramolecular steric interactions of the bulky
octamethyltitanocene and (diphenylphosphino)ferrocene
moieties. An inspection of intermolecular contacts has
revealed that the solid-state packing in (I) is dictated mostly
by steric requirements. The only notable exception is edge-to-
face interaction between H21 and the ferrocene cyclopenta-
dienyl Cp1 ring in a neighbouring molecule [H21Á Á ÁCg1i =
3
[FeTi(C9H13)2(C6H4O2)(C17H14P)]
Mr = 703.48
Dx = 1.337 Mg m
Mo Kꢇ radiation
Monoclinic, P21=c
Cell parameters from 97 200
re¯ections
Ê
a = 8.4660 (1) A
ꢈ = 1.0±27.5ꢀ
ꢁ = 0.72 mm
T = 150 K
Ê
b = 29.5260 (3) A
1
Ê
c = 14.1002 (1) A
ꢆ = 97.3941 (5)ꢀ
V = 3495.28 (6) A
Z = 4
3
Ê
Prism, dark red±brown
0.75 Â 0.50 Â 0.40 mm
Data collection
Nonius KappaCCD area-detector
diffractometer
! scans
Absorption correction: multi-scan
(SORTAV; Blessing, 1997)
Tmin = 0.606, Tmax = 0.757
47 188 measured re¯ections
7976 independent re¯ections
6981 re¯ections with I > 2ꢉ(I)
Rint = 0.049
ꢈmax = 27.5ꢀ
h = 0 ! 10
i
i
Ê
Ê
2.845 A, C21Á Á ÁCg1 = 3.708 (2) A and C21ÐH21Á Á ÁCg1 =
k = 38 ! 38
1
155.0ꢀ; symmetry code: (i) x 1, 12 y, + z].
l = 18 ! 18
2
ꢁ
Acta Cryst. (2002). C58, m116±m118
Karel Mach et al.
[FeTi(C9H13)2(C6H4O2)(C17H14P)] m117

metal-organic compounds
Re®nement
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: GD1183). Services for accessing these data are
described at the back of the journal.
Re®nement on F2
R[F2 > 2ꢉ(F2)] = 0.033
wR(F2) = 0.085
S = 1.04
7976 re¯ections
w = 1/[ꢉ2(Fo2) + (0.0368P)2
+ 1.8480P]
where P = (Fo2 + 2Fc2)/3
(Á/ꢉ)max = 0.001
3
Ê
Áꢊmax = 0.29 e A
References
3
Ê
0.34 e A
415 parameters
H-atom parameters constrained
Áꢊmin
=
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Polidori, G. & Camalli, M. (1994). J. Appl. Cryst. 27, 435.
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Ê
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Minor, 1997); data
Minor, 1997) and
HKL SCALEPACK (Otwinowski
reduction: HKL DENZO (Otwinowski
&
&
SCALEPACK; program(s) used to solve structure: SIR92
(Altomare et al., 1994); program(s) used to re®ne structure:
SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek,
1999); software used to prepare material for publication: SHELXL97
and PLATON.
Æ
Æ
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Ï
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Æ
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Ï
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543±550.
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È
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Æ
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Ï
1204±1205, and references therein.
Ï
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 Ï
Æ
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Ï
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Ï
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Financial support from the Grant Agency of the Czech
Republic is gratefully acknowledged (grant Nos. 203/01/P002,
203/99/0846 and 203/99/M037).
 Ï
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Troyanov, S. I. (1996). J. Organomet. Chem. 506, 241±251.
ꢁ
m118 Karel Mach et al. [FeTi(C9H13)2(C6H4O2)(C17H14P)]
Acta Cryst. (2002). C58, m116±m118