Syntheses, structures, and properties of phenyltrihydroborate complexes of zirconocene and titanocene

Article abstract of DOI:10.1016/j.jorganchem.2004.09.026

The phenyltrihydroborate complexes, Cp₂ZrCl{(μ-H) ₂BHPh}, 1, and Cp₂Zr{(μ-H)₂BHPh}₂ ? (1/2 toluene), 2, were prepared from the reactions of Cp ₂ZrCl₂ with one and two moles of LiBH₃Ph. The Zr-H-B bonds in 2 are stable under vacuum at 100°C for hours without significant decomposition. An inductive effect has been proposed for this strong interaction. This hydrogen bridge bond can be broken upon reacting with the Lewis base N(C₂H₅)₃ to produce (C ₂H₅)₃N ? BH₂Ph and the zirconium hydride compound Cp₂ZrH{(μ-H)₂BHPh}, 3. Compound 3 also can be prepared from the reaction of Cp₂ZrHCl with LiBH₃Ph. The reaction of 1 with the Lewis acid B(C₆F ₅)₃ is solvent dependent, the metathesis product Cp ₂ZrCl{(μ-H)₂B(C₆F₅)₂}, 4, was formed in the toluene solution, whereas the ionic complex [Cp ₂ZrCl(OEt₂)][HB(C₆F₅)₃], 5, was isolated from the ether solution. The reaction of titanocene dichloride, Cp₂TiCl₂, with LiBH₃Ph produced a 17-electron, paramagnetic complex, Cp₂Ti{(μ-H)₂BHPh}, 6. Single crystal X-ray structures of 1, 2, 3, 4, 5, and 6 were also determined. A coplanar structure of the four bridge hydrogens in 2 was observed.

Full text of DOI:10.1016/j.jorganchem.2004.09.026

Journal of Organometallic Chemistry 690 (2005) 291–300
www.elsevier.com/locate/jorganchem
Syntheses, structures, and properties of
phenyltrihydroborate complexes of zirconocene and titanocene
a,
a
a
a
Fu-Chen Liu *, Jung-Hua Chen , Shou-Chon Chen , Ko-Yu Chen ,
b
Gene-Hsian Lee , Shie-Ming Peng
b
a
Department of Chemistry, National Dong Hwa University, Hualien 974, Taiwan, ROC
b
Department of Chemistry, National Taiwan University, Taipai 106, Taiwan, ROC
Received 17 May 2004; accepted 14 September 2004
Available online 14 October 2004
Abstract
The phenyltrihydroborate complexes, Cp2ZrCl{(l-H)2BHPh}, 1, and Cp2Zr{(l-H)2BHPh}2 Æ (1/2 toluene), 2, were prepared
from the reactions of Cp2ZrCl2 with one and two moles of LiBH3Ph. The Zr–H–B bonds in 2 are stable under vacuum at 100
ꢀC for hours without significant decomposition. An inductive effect has been proposed for this strong interaction. This hydrogen
bridge bond can be broken upon reacting with the Lewis base N(C2H5)3 to produce (C2H5)3N Æ BH2Ph and the zirconium hydride
compound Cp2ZrH{(l-H)2BHPh}, 3. Compound 3 also can be prepared from the reaction of Cp2ZrHCl with LiBH3Ph. The reac-
tion of 1 with the Lewis acid B(C6F5)3 is solvent dependent, the metathesis product Cp2ZrCl{(l-H)2B(C6F5)2}, 4, was formed in the
toluene solution, whereas the ionic complex [Cp2ZrCl(OEt2)][HB(C6F5)3], 5, was isolated from the ether solution. The reaction of
titanocene dichloride, Cp2TiCl2, with LiBH3Ph produced a 17-electron, paramagnetic complex, Cp2Ti{(l-H)2BHPh}, 6. Single crys-
tal X-ray structures of 1, 2, 3, 4, 5, and 6 were also determined. A coplanar structure of the four bridge hydrogens in 2 was observed.
ꢁ 2004 Elsevier B.V. All rights reserved.
Keywords: Phenyltrihydroborate; Organohydroborate; Hydroborate; Crystal structure; Zirconocene; Titanocene
1. Introduction
[BH3C(SiMe3)3]ꢀ anions [3,5]. While many methyl-
trihydroborate, [BH3CH3]ꢀ, and cyanotrihydroborate,
[BH3CN]ꢀ, complexes have been reported, most of the
cyanotrihydroborate anion bonds to the metal through
a nitrogen atom and, except for five compounds [2a–c]
the methyltrihydroborate complexes involve actinide
and lanthanide metals. The chemical properties of these
organotrihydroborate complexes are not well studied.
In our recent study, we found that the Zr–H–B bond
of the methyltrihydroborate disubstituted complex
Cp2Zr{(l-H)2BHCH3}2 [2a] is significantly weaker than
that of the tetrahydroborate complex Cp2Zr{(l-
H)2BH2}2 [6] or the organodihydroborate complex
Cp2Zr{(l-H)2BC5H10}2 [7]. While complex Cp2Zr-
{(l-H)2BC5H10}2 is stable under vacuum at room tem-
perature and complex Cp2Zr{(l-H)2BH2}2 can be sub-
limed under reduced pressure at 120 ꢀC, complex
Many tetrahydroborate metal complexes have been
studied extensively during the past 50 years [1], however,
only a few examples of the organohydroborate metal
complexes have been reported. While most of the known
complexes are organodihydroborate compounds, the
organotrihydroborate complexes are rare. To our
knowledge, there are only several organotrihydroborate
anions, including [BH3CH3]ꢀ [2], [BH3CO2R]ꢀ (R = H,
CH3, C2H5) [3], [BH3CN]ꢀ [4], and [BH3C(SiMe3)3]ꢀ
[5], that have been used to prepare the corresponding
complexes. However, only few complexes were prepared
from the [BH3CO2R]ꢀ (R = H, CH3, C2H5) or the
*
Corresponding author. Tel.: +038633601; fax: +038633570.
E-mail address: fcliu@mail.ndhu.tw (F.-C. Liu).
0022-328X/$ - see front matter ꢁ 2004 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2004.09.026

292
F.-C. Liu et al. / Journal of Organometallic Chemistry 690 (2005) 291–300
Cp2Zr{(l-H)2BHCH3}2 decomposes to Cp2ZrH{(l-
H)2BHCH3} and (CH3BH2)2 under vacuum at room
temperature [2a]. This weak Zr–H–B bond is unexpected
and we proposed that this weak Zr–H–B interaction is
caused by the electron releasing property of the methyl
group on the boron atom. This effect causes the accumu-
lation of the excess electron density on the central zirco-
nium atom and destabilizes the Zr–H–B interaction. In
the present study we are interested to examine this prop-
osition and have selected phenyltrihydroborate com-
plexes for study. We present the syntheses, structures,
and the properties of the phenyltrihydroborate deriva-
tives of the zirconocene and titanocene complexes, and
we also report the reaction of Cp2ZrCl{(l-H)2BHPh}
with the Lewis acid, B(C6F5)3, in non-coordinating
and coordinating solvent.
H
H
B
H
H
H
H
CH3
Zr
Zr
1/2 (CH3BH2)2
+
H
H
H
H
B
B
CH3
CH3
ð3Þ
Compound 2 was subjected to sublimation under re-
duced pressure; however, compound 3 did not form,
even when the temperature was raised to 100 ꢀC for
4 h. After heating, most of the crystals turned light
pink and the metal luster disappeared. However, the
NMR spectra indicated that the compound Cp2Zr{(l-
H)2BHPh}2 was still intact, and only the absence of
the toluene signals was observed. These NMR spectra
suggest that the Zr–H–B bond strength of compound
2 is comparable to that of the tetrahydroborate com-
plex, Cp2Zr{(l-H)2BH2}2 [6], which is stable above
100 ꢀC under reduced pressure. From a steric point
of view, the phenyl group on the boron atom has a lar-
ger steric requirement than that of the methyl group on
compound Cp2Zr{(l-H)2BHCH3}2, and this factor
might destabilize compound 2, however, this result
was not observed [8]. On the other hand, the inductive
effect of the substituent on the boron atom may play a
key role for its stability. Formally, the zirconium is
associated with 20 valence electrons in compound 2,
the same as the methyltrihydroborate disubstituted
compound Cp2Zr{(l-H)2BHCH3}2. Unlike the electron
donor methyl substituted group on compound
Cp2Zr{(l-H)2BHCH3}2, which directs electron density
to the zirconium and weakens the Zr–H–B bond, the
electron withdrawing phenyl substituted group on com-
pound 2 relieves the accumulation of excess electron
density on the zirconium and stabilizes the Zr–H–B
interaction.
2. Results and discussion
2.1. Formation and properties of Cp2ZrCl{(l-H)2BHPh}
(1), Cp2Zr{(l-H)2BHPh}2 Æ (1/2 toluene) (2), Cp2ZrH
{(l-H)2BHPh} (3), Cp2ZrCl{(l-H)2B(C6F5)2} (4),
[Cp2ZrCl(OEt2)][HB(C6F5)3] (5), and Cp2Ti{(l-
H)2BHPh} (6)
The phenyltrihydroborate compounds Cp2ZrCl{(l-
H)2BHPh}, 1, and Cp2Zr{(l-H)2BHPh}2 Æ (1/2 toluene),
2, were prepared from the reactions of Cp2ZrCl2 with
one and two moles of LiBH3Ph, as shown in Eqs. (1)
and (2). Compound 2 was crystallized from toluene
solution and contained one-half solvent molecule.
Cl
Cl
Zr
Zr
H
PhBH3Li
+
LiCl
+
Cl
H
27
B
H
Compound 3 can be prepared from the reaction of
Cp2Zr{(l-H)2BHPh}2 with N(C2H5)3 in toluene solu-
tion, as shown in Eq. (4).
Ph
1
ð1Þ
H
H
B
H
H
H
H
H
H
B
Ph
Zr
Zr
H
H
N(C2H5)3
+
Cl
Cl
Ph
(C2H5)3N BH2Ph
+
Zr
Zr
2 PhBH3Li
+
2 LiCl
+
H
H
H
H
B
B
H
H
Ph
Ph
B
2
3
Ph
2
ð4Þ
ð2Þ
These two products, 3 and (C2H5)3N Æ BH2Ph, were iso-
lated from repeated crystallizations and manual separa-
tions. The second method to prepare compound 3 is
from the reaction of Cp2ZrHCl with LiBH3Ph in toluene
solution, as shown in Eq. (5). After reacting for one day,
only 50% yield of compound 3 was observed from the
boron spectra and compound 3 did not increase signifi-
cantly for further reaction.
Previously we reported the preparation of the zirco-
nium hydride compound Cp2ZrH{(l-H)2BHCH3}
through the decomposition of the methyltrihydroborate
disubstituted compound Cp2Zr{(l-H)2BHCH3}2 under
reduced pressure at room temperature [2a] (Eq. (3)).
An attempt to prepare the zirconium hydride compound
Cp2ZrH{(l-H)2BHPh}, 3, using the same method failed.

F.-C. Liu et al. / Journal of Organometallic Chemistry 690 (2005) 291–300
293
coupling constants of these organotrihydroborate
complexes are comparable with that of the free lig-
ands. This behavior is different from that of the tetra-
hydroborate or cyclic organodihydroborate complexes,
which display smaller coupling constants than that of
the free ligands [1a,7,10].
H
H
Zr
Zr
H
PhBH3Li
+
LiCl
+
Cl
H
B
H
Ph
3
In the 1H NMR spectra, the signals of the BH3
hydrogens of complexes 1, 2, and 3 appeared at 1.00,
1.39, and ꢀ0.42 ppm, as a broad quartet, respectively.
The terminal and bridge hydrogens in these complexes
are indistinguishable in the proton spectra [1a]. The
chemical shift of the terminal Zr–H hydride of com-
pound 3 appears at 4.48 ppm, as a broad signal that falls
within the range observed for other zirconium hydride
complexes [2b, 6b,7,12,13].
The boron signal of compound 4 appears at ꢀ10.6
ppm (t, JB–H = 67 Hz). This chemical shift and coupling
constant are consistent with that of the bis(pentafluoro-
phenyl)borate zirconocene complexes [9,14]. The bridge
Zr–H–B hydrogens appear at 0.38 ppm as a broad
signal.
The NMR data of compound 5 was collected in deu-
teriated THF where the coordinating ether was replaced
by the deuteriated THF. The terminal B–H hydrogen
appeared at 3.80 ppm as a broad quartet. The anionic
borate signal appeared at ꢀ25.9 ppm as a doublet
(JB–H = 93 Hz) in the boron spectrum. These chemical
shifts and coupling constant are consistent with other io-
nic complexes with the same anion [15].
ð5Þ
The reaction of 1 with B(C6F5)3 produces the cova-
lent metathesis product Cp2ZrCl{(l-H)2B(C6F5)2}, 4,
in toluene solution, and produces the ionic complex
[Cp2ZrCl(OEt2)][HB(C6F5)3], 5, in diethyl ether, as
shown in Eq. (6).
Cl
H
Zr
C6F5
B
C6F5
Cl
H
H
toluene
ether
Zr
H
B
+
B(C6F5)3
4
H
Ph
1
Cl
Zr
HB(C F5)3
6
OEt2
5
ð6Þ
These reactions are not balanced since the by-products
could not be identified through an NMR study. We
could not prepare pure compound 4 on a large scale,
since a small amount of by-product could not be re-
moved successfully, however, we isolated a few crystals
which were sufficient for the NMR study and the solid
state X-ray structure determination. Compound 4 has
also been prepared from the reaction of Cp2ZrHCl with
HB(C6F5)2 in a NMR tube, and identified through a
multinuclear NMR spectroscopy [9]. Compound 5 is
soluble in THF and acetontrile, however, it gradually
decomposed in these solvents during the NMR measure-
ments; one of the decomposition products is Cp2ZrCl2.
The boron chemical shifts of compounds 1, 2, and
3 appear as a quartet at d 2.37 (JB–H = 76 Hz), ꢀ6.0
(JB–H = 70 Hz), and 16.62 ppm (JB–H = 73 Hz), respec-
tively. The apparent equivalence of bridge and termi-
nal hydrogens of the hydroborate compounds at
ambient temperature is well known [1a], which causes
the quartet nature of the boron signals. These reso-
nances are downfield with respect to that of lithium
phenyltrihydroborate (ꢀ26.5 ppm, JB–H = 75 Hz).
These results are consistent with those obtained from
methyltrihydroborate analogs, where the boron chem-
ical shifts of the methyltrihydroborate complexes
Cp2ZrCl{(l-H)2BHCH3} [2a], Cp2Zr{(l-H)2BHCH3}2
[2a], and Cp2ZrH{(l-H)2BHCH3} [2b] appear at
3.84, ꢀ6.82, and 18.2 ppm, respectively. The B–H
The IR spectrum of compound 3 displays a broad
signal at 1597 cmꢀ1 assigned to the Zr–H stretching
mode, which agrees with bands observed in the IR
spectra of other zirconium hydride complexes
[2b,6b,7,12].
Compound Cp2Ti{(l-H)2BHPh}, 6, was prepared
from the reaction of Cp2TiCl2 with two moles of
LiBH3Ph, as shown in Eq. (7).
H
H
H
Cl
Cl
B
Ti
Ti
+ 2 PhBH3Li
+
2 LiCl
Ph
6
+
1/2 (PhBH2)2
1/2 H2
+
ð7Þ
During the reaction, hydrogen gas was evolved and the
solution turned purple in color. The titanium was re-
duced from Ti(IV) to Ti(III), producing a 17-electron
species. No obvious signal was observed in the 100
1
ppm range in the boron spectra. In the H NMR spec-
trum, three signals were observed in the range 6.55–
7.68 ppm. These signals appeared in the range of the
aromatic protons and were assigned to the resonances
1
of the phenyl protons, using a proton detected H–13C
correlation experiment (heteronuclear multiple quantum

294
F.-C. Liu et al. / Journal of Organometallic Chemistry 690 (2005) 291–300
coherence, HMQC). A broad signal that appeared at
7.68 ppm was assigned to the resonance of the b proton
of the phenyl group, which is five bonds away from the
paramagnetic center. This result is consistent with our
previous study of the cyclic organohydroborate com-
plexes of titanocene where the proton signals are
NMR silent until they are five bonds away from the par-
amagnetic center [16].
2.2. Molecular structures
The molecular structures of 1, 2, 3, 4, 5, and 6 were
determined by single-crystal X-ray diffraction analysis,
and they are shown in Figs. 1–6. Crystallographic data
and selected bond distances and bond angles are given
in Tables 1–4. A complete listing of distances and an-
gles, as well as the atomic coordinates, can be found
in the Supporting Information.
Fig. 2. Molecular structure of Cp2Zr{(l-H)2BHPh}2 Æ (1/2 toluene)
(2), showing 50% probability thermal ellipsoids. Toluene molecule is
omitted.
The coordination geometry around the zirconium
atom in 1, 2, 3, and 4 is best described as a distorted tet-
rahedron. At the corners of the tetrahedron are the cen-
ters of the two Cp rings, a boron atom which is
connected to the zirconium through two bridge hydro-
gens, and a Cl (1 and 4), or a second boron atom (2)
which is also connected to the zirconium through two
bridge hydrogens, or a hydrogen atom (3). Two inde-
pendent molecules of 4 were found in the unit cell. These
two molecules have slightly different bond distances and
angles, and only one molecule is shown in Fig. 4.
In compound 2, one-half solvent molecule, toluene,
was found in the crystal lattice and one Cp ring dis-
played 50% occupancy. There is a crystallographically
imposed mirror plane which passes through the Zr,
C(7), C(15), C(16), and C(19), to generate the rest of the
molecule. The carbon atoms C(15), C(16), and C(19) are
from the solvent, they are not shown in Fig. 2. The four
bridge hydrogens are coplanar. The coplanarity of the
four bridge hydrogens in Cp2Zr{(l-H)2BH2}2 has been
Fig. 3. Molecular structure of Cp2ZrH{(l-H)2BHPh} (3), showing
50% probability thermal ellipsoids.
Fig. 4. Molecular structure of Cp2ZrCl{(l-H)2B(C6F5)2} (4), showing
50% probability thermal ellipsoids.
suggested by Hoffmann and Lauher through molecular
orbital calculations [17]. Although the solid state struc-
ture of Cp2Zr{(l-H)2BH2}2 has been reported, hydro-
gen atoms around the boron atom were not found due
to the low quality of the crystal [18]. Some metallocene
hydroborate disubstituted complexes have been re-
ported, which include (C5H4Me)2Hf{(l-H)2BH2}2 [19],
Fig. 1. Molecular structure of Cp2ZrCl{(l-H)2BHPh} (1), showing
50% probability thermal ellipsoids.

F.-C. Liu et al. / Journal of Organometallic Chemistry 690 (2005) 291–300
295
relatively small and the steric effect is minimal. This
may suggest the electronic effect dominates the metal–
ligand interaction. Support for this argument is given
by the two cyclic organodihydroborate compounds,
˚
Cp2ZrH{(l-H)2BC5H10} (2.587(7) A) [7] and Cp2ZrH-
˚
{(l-H)2BC4H8} (2.548(4) A) [12], both have an electron
releasing alkyl group, which have Zr–B distances com-
parable to that in Cp2ZrH{(l-H)2BHCH3}, but are
longer than that observed in the electron withdrawing
substituted compound 3.
˚
The Zr–B distance is 2.604(8) A in 4. It is slightly
longer than that in 1, however, it is significantly shorter
Fig. 5. Molecular structure of the cation [Cp2ZrCl(OC4H10)]+ (5),
showing 30% probability thermal ellipsoids.
than the Zr–B distances found in the bulky bis(penta-
fluorophenyl)borate
compound
Cp2Zr{(l-H)2B-
˚
(C6F5)2}2 (2.696(10) and 2.679(10) A), due to the steric
reason [14].
The bridge Zr–Hb and bridge B–Hb distances of com-
pounds 1–4 are listed in Table 3. Comparing with the
˚
bridge Zr–H distances (1.96(5)–2.17(9) A) and the
˚
bridge B–H distances (1.10(9)–1.32(5) A) of the zircono-
cene hydroborate complexes [2a,7,9,12,21], compound 3
has a shorter bridge B–H distance and compound 4 has
a longer Zr–H distance. These may account for the short
Zr–B distance in 3 and long Zr–B distance in 4.
˚
The terminal B–Ht bond distances of 1 (1.22(5) A), 2
˚
˚
(1.21(6) A), and 3 (1.14(6) A) are comparable with one
of the bridge B–H bond distances and are longer than
the other one found in each compound. These results
are different compared with those were observed in the
tetrahydroborate complexes where the bridge B–H bond
Fig. 6. Molecular structure of Cp2Ti{(l-H)2BHPh} (6), showing 50%
probability thermal ellipsoids.
˚
Cp2Zr{(l-H)2BC5H10}2 [7], Cp2Zr{(l-H)2BHCH3}2
[2a], and Cp2Zr{(l-H)2B(C6H5)2}2 [9], the bridge hydro-
gen atoms in these compounds are not coplanar. In
distances are 0.06–0.10 A longer than the terminal B–H
bond distances [1a,21].
˚
The Zr–Cl distance is 2.4844(13) A in 1 and 2.460(2)
˚
˚
A in 4. It is comparable to the Zr–Cl distances observed
compound 2, the zirconium atom is 0.1831 A above,
˚
and each boron atom is 0.1719 A below the plane de-
in other hydroborate complexes [2a,10,22].
The terminal Zr–H distance in 3 is 1.70(7) A. This
˚
fined by the four bridge hydrogens. The B–Zr–B angle
of 2 is 107.9(3)ꢀ which is larger than that in compounds
distance is significantly shorter than that in (g5-
˚
Cp2Zr{(l-H)2BH2}2
(103.3(7)ꢀ)
[18],
Cp2Zr{(l-
C5Me5)ZrH(g-C8H8) (1.81 A) [23], Cp2ZrH{(l-
˚
H)2BC5H10}2 (89.3ꢀ) [7] and Cp2Zr{(l-H)2BHCH3}2
(99.7(3)ꢀ) [2a,20].
The Zr–B distances are 2.592(4) in 1, 2.628(6) in 2,
H)2BC5H10} (1.786(4) A) [7], Cp2ZrH{(l-H)2BHCH3}
˚
(1.78(2) A) [2b], and {ZrH(l-H)(g-C5H4Me)2}2
˚
(1.78(2) A) [24], but is comparable to those distances ob-
˚
˚
and 2.538(11) A in 3. These distances reflect the steric
served in Cp2ZrH{(l-H)2BC4H8} (1.68(5) A) [12] and
(g -C8H11)ZrH(dmpe) (1.67 A) [25].
5
˚
bulk of the fourth ligand which is Cl (1), BH3Ph (2),
and H (3), respectively. However, an interesting result
is observed when these distances are compared with
those in the methyltrihydroborate analogs: Cp2ZrCl-
{(l-H)2BHCH3} (2.578(6) A) [2a], Cp2Zr{(l-
˚
H)2BHCH3}2 (2.599(8) and 2.612(9) A) [2a], and
The coordination geometry around the zirconium
atom in 5 is best described as a distorted tetrahedron,
where the centers of the two Cp rings, a chlorine atom,
and an oxygen atom occupy the corners of the tetrahe-
˚
˚
dron. The Zr–Cl distance is 2.4148(17) A and the Zr–O
˚
˚
distance is 2.211(3) A. The Zr–Cl distance is slightly
Cp2ZrH{(l-H)2BHCH3} (2.558(4) A) [2b]. Although
the phenyl substituted compounds 1 and 2 have longer
Zr–B distances compared with the methyltrihydroborate
analogs, compound 3 has a shorter Zr–B distance than
that in compound Cp2ZrH{(l-H)2BHCH3}. Obviously,
the steric bulk of the phenyl substituted group alone
does not account for the discrepancy in these distances.
Compared with other ligands, the hydride ligand is
shorter than that in compounds 1, 4, and other organ-
ohydroborate compound [2a,10,22]. The Zr–O distance
was consistent with that observed in [Cp2Zr(OEt2)-
˚
(OEt)][HB(C6F5)] (2.209(8) A) [15] and is slightly longer
˚
than the sum of the covalent radii, 2.16 A [26]. These
bond distances suggest a weak interaction between the
zirconium atom and the ether molecule, which has been

296
F.-C. Liu et al. / Journal of Organometallic Chemistry 690 (2005) 291–300
Table 1
Crystallographic data for Cp2ZrCl{(l-H)2BHPh} (1), Cp2Zr{(l-H)2BHPh}2 Æ (1/2 toluene) (2), and Cp2ZrH{(l-H)2BHPh} (3)
Empirical formula
Fw
C16H18BClZr
347.78
150(1)
C25.5H30B2Zr
449.33
150(1)
C16H19BZr
313.34
150(1)
T (K)
Cryst system
Space group
Monoclinic
Cc
Tetragonal
ꢀ
Monoclinic
Pn
P421m
˚
a (A)
17.5766(3)
8.8102(2)
11.0359(2)
16.9483(2)
16.9483(2)
7.9935(1)
6.1535(1)
8.2688(2)
14.5763(3)
˚
b (A)
˚
c (A)
a (ꢀ)
b (ꢀ)
c (ꢀ)
114.0895(9)
99.9431(13)
3
˚
V (A )
1560.11(5)
4
1.481
2296.09(5)
4
1.300
730.53(3)
2
1.424
Z
qcalc. (g/cm3)
Cryst size (mm3)
0.40 · 0.32 · 0.25
Mo Ka (0.71073)
2.54–27.49
ꢀ22 6 h 6 22
ꢀ10 6 k 6 11
ꢀ14 6 l 6 14
9597
0.25 · 0.25 · 0.23
Mo Ka (0.71073)
1.70–27.50
ꢀ22 6 h 6 21
ꢀ22 6 k 6 22
ꢀ10 6 l 6 10
16177
0.30 · 0.20 · 0.16
Mo Ka (0.71073)
2.46–27.50
ꢀ7 6 h 6 7
ꢀ10 6 k 6 10
ꢀ18 6 l 6 17
9723
˚
Radiation (k, A)
2h Limits (ꢀ)
Index ranges
Reflns collected
Unique reflns
3331
704
2759
932
3112
320
Unique reflns [I > 2.0r (I)]
Completeness to h (%)
99.8
0.859
100.0
0.487
99.9
0.732
l (mmꢀ1
Max/min transm
)
0.843, 0.738
3331/2/185
0.0329
0.888, 0.821
2759/0/136
0.0462
0.881, 0.799
3112/2/177
0.0387
Data/restraints/parameters
a
R1 [I > 2.0r(I)]
wR2 (all data)
b
0.0919
0.0446
1.192
0.1153
0.0731
1.118
0.1003
0.0460
1.145
Rint
GOF on F2
P
P
a
R1 = ||Fo||ꢀjFc||/ ||Foj.
P
P
2
2 1=2
b
wR2 ¼ f wðF 2o ꢀ F c2Þ = wðF 2oÞ g
.
confirmed through a NMR study where the coordinated
ether molecule was replaced by the THF molecule.
The coordination geometry of the titanium atom in
compound 6 is best described as a trigonal. The centers
of the two Cp rings and the boron atom which is con-
nected to the titanium atom through two bridge hydro-
gens define the trigonal coordination geometry of the
metal center. The bond distances of Ti–B, bridge Ti–
Hb, and bridge B–Hb are all consistent with those in
B(C6F5)3 were purchased from Strem and used as re-
ceived. LiBH3Ph was prepared according to the litera-
ture method [11a]. Elemental analyses were recorded
1
on a Hitachi 270–30 spectrometer. H NMR spectra (d
(TMS) 0.00 ppm) were recorded on a Varian Mercury
200 spectrometer operating at 199.975 MHz or recorded
on a Varian Unity Inova 600 spectrometer operating at
599.948 MHz. 11B spectra (externally referenced to
BF3 Æ OEt2 (d 0.00 ppm)) were recorded on a Varian
Unity Inova 600 operating at 192.481 MHz. Infrared
spectra were recorded on a Jasco FT/IR-460 Plus spec-
trometer with 2 cmꢀ1 resolution.
other
titanocene
organohydroborate
complexes
˚
[2a,15,16,27]. The terminal B–H distance of 1.14(2) A
is shorter than the bridge B–H distances.
3.2. X-ray crystal structure determination
3. Experimental
Suitable single crystals of 1, 2, 3, 4, 5, and 6 were
mounted and sealed inside glass capillaries under nitro-
gen. Crystallographic data collections were carried out
on a Nonius KappaCCD diffractometer equipped with
graphite-monochromated Mo Ka radiation (k =
3.1. General procedures
All manipulations were carried out using a standard
high vacuum line or in a drybox under an atmosphere
of nitrogen. Diethyl ether and toluene were dried over
Na/benzophenone and were freshly distilled prior to
use. Cp2ZrCl2, Cp2TiCl2, and LiAlH4 were purchased
from Aldrich and used as received. PhB(OH)2 and
˚
0.71073 A) at 150(1) K. Cell parameters were retrieved
and refined using DENZO-SMN [28] software on all
reflections. Data reduction was performed with the
DENZO-SMN [28] software. An empirical absorption
was based on the symmetry-equivalent reflections and

F.-C. Liu et al. / Journal of Organometallic Chemistry 690 (2005) 291–300
297
Table 2
Crystallographic data for Cp2ZrCl{(l-H)2B(C6F5)2} (4), [Cp2ZrCl(OC4H10)][HB(C6F5)] (5), and Cp2Ti{(l-H)2BHPh} (6)
Empirical formula
Fw
C22H12B2ClF10Zr
603.8
150(1)
C32H21BClF15OZr
843.97
150(1)
C16H18BTi
269.01
150(1)
T (K)
Crystal system
Space group
Triclinic
ꢀ
Monoclinic
P21/n
Orthorhombic
Pbca
P1
˚
a (A)
7.3519(1)
16.2967(3)
18.1612(3)
89.9137(7)
89.1789(7)
83.7631(6)
2162.82(6)
4
12.5124(6)
20.5626(10)
12.9849(6)
11.47130(10)
14.3734(2)
16.7301(2)
˚
b (A)
˚
c (A)
a (ꢀ)
b (ꢀ)
c (ꢀ)
106.118(1)
3
˚
V (A )
3209.5(3)
4
1.747
2758.49(6)
8
1.296
Z
qcalc. (g/cm3)
1.854
Cryst size (mm3)
0.25 · 0.25 · 0.10
Mo Ka (0.71073)
1.12–27.50
ꢀ9 6 h 6 9
ꢀ21 6 k 6 21
ꢀ23 6 l 6 23
29319
0.23 · 0.20 · 0.15
Mo Ka (0.71073)
1.91–27.50
ꢀ15 6 h 6 16
ꢀ26 6 k 6 26
ꢀ16 6 l 6 15
29319
0.25 · 0.20 · 0.10
Mo Ka (0.71073)
2.43–27.50
ꢀ14 6 h 6 14
ꢀ18 6 k 6 18
ꢀ21 6 l 6 21
20458
˚
Radiation (k, A)
2h Limits (ꢀ)
Index ranges
Reflns collected
Uique reflns
9824
1184
7372
1672
3166
1128
Uique reflns [I > 2.0r(I)]
Cmpleteness to h (%)
98.6
0.727
99.9
0.541
99.9
0.598
l (mmꢀ1
Max/min transm
)
0.943, 0.821
9824/1/648
0.0785
0.9233, 0.8857
7372/0/464
0.0707
0.945, 0.859
3166/0/176
0.0364
Data/restraints/parameters
a
R1 [I > 2.0r(I)]
wR2 (all data)
b
0.2344
0.0655
1.098
0.1787
0.0525
1.062
0.0985
0.0507
1.051
Rint
GOF on F2
P
P
a
R1 = ||Fo||ꢀjFc||/ ||Foj.
P
P
2
2 1=2
b
wR2 ¼ f wðF 2o ꢀ F c2Þ = wðF 2oÞ g
.
Table 3
˚
Selected bond distances (A) and bond angles (ꢀ) for Cp2ZrCl{(l-H)2BHPh} (1), Cp2Zr{(l-H)2BHPh}2 Æ (1/2 toluene) (2), Cp2ZrH{(l-H)2BHPh} (3),
Cp2ZrCl{(l-H)2B(C6F5)2} (4), and Cp2Ti{(l-H)2BHPh} (6)
1
2
3
4
6
Bond distances
M–B
2.592(4)
2.628(6)
2.538(11)
2.604(8)
2.619(8)
2.302(10)
2.18(8)
2.17(7)
2.30(8)
1.15(9)
1. 03(8)
1.109(8)
1.36(8)
2.417(2)
M–Hbridge
2.06(4)
2.10(5)
1.90(5)
2.09(6)
2.09(7)
2.07(7)
1.875(18)
1.904(18)
B–Hbridge
1.15(4)
1.23(4)
1.16(5)
1.22(6)
1.04(8)
1.11(7)
1.221(18)
1.218(18)
B–Hterminal
Zr–Cl
1.22(5)
2.4844(13)
1.21(6)
1.14(6)
1.70(7)
1.14(2)
2.460(2)
2.456(2)
Zr–Hterminal
Bond angles
B–Zr–B
B–Zr–Cl
107.9(3)
100.10(11)
99.2(2)
110.5(2)
B–Zr–Hterminal
97(2)

298
F.-C. Liu et al. / Journal of Organometallic Chemistry 690 (2005) 291–300
Table 4
3.3.2. Cp2Zr{(l-H)2BHPh}2 Æ (1/2 toluene) (2)
˚
Selected bond distances (A) and bond angles (ꢀ) for
[Cp2ZrCl(OC4H10)][HB(C6F5)3] (5)
In the drybox, 407 mg (4.2 mmol) of LiBH3Ph and
584.7 mg (2.0 mmol) of Cp2ZrCl2 were charged into a
flask. The flask was evacuated, and 20 ml of toluene
was condensed to the flask at ꢀ78 ꢀC. The system was
warmed to room temperature over a 1 h period and stir-
red for additional 10 h. The LiCl was separated from the
solution through filtration and the solvent was reduced
to about 10 ml. The toluene solution was kept at ꢀ35
ꢀC for crystallization. A 776 mg (86.3% yield) of colorless
product was isolated. 11B NMR (C6H6): d ꢀ6.0 ppm (q,
Bond distances
Zr–O(1)
2.211(3)
2.4148(17)
1.461(6)
1.498(7)
1.489(9)
1.452(11)
Zr–Cl(1)
O(1)–C(1)
O(1)–C(3)
C(1)–C(2)
C(3)–C(4)
Bond angles
O(1)–Zr–Cl(1)
C(1)–O(1)–C(3)
C(1)–O(1)–Zr
C(3)–O(1)–Zr
96.53(11)
114.7(4)
120.4(3)
120.9(3)
1
JB–H = 70 Hz). H NMR (C6D6): d 7.65–7.27 (m, 10H,
Ph), 7.17–6.95 (m, Ph, toluene), 5.51 (s, 10H, Cp), 2.07
(s, CH3, toluene), and 1.39 ppm (br, 6H, BH3). IR(KBr):
3140(vw), 3103(w), 3084(vw), 3060(w), 2997(w),
2375(m), 2345(w), 2256(vw), 2172(w), 2094(m),
1484(vw), 1460(vw), 1438(w), 1342(m), 1253(s),
1175(w), 1124(vw), 1085(m), 1023(m), 929(vw), 848(w),
824(vs), 766(vw), 728(s), 701(m), 671(w), 537(vw), and
464(vw) cmꢀ1. Anal. Calc. for C25.5H30B2Zr: C, 68.16;
H, 6.73. Found: C, 67.82; H, 6.65%.
was applied to the data using the SORTAV [29] pro-
gram. The structure was solved using the SHELXS-97
[30] program and refined using SHELXL-97 [31] pro-
gram by full-matrix least-squares on F2 values. All
non-hydrogen atoms, except for C10–C19 in com-
pound 2, were refined with anisotropic thermal param-
eters. Hydrogen atoms attached to the zirconium and
the boron atoms, and the carbon atoms C10–C19 in
compound 2 were located from the difference Fourier
map and were refined isotropically. Hydrogen atoms
attached to the carbons were fixed at calculated posi-
tions and refined using a riding mode. Detailed crystal
data are listed in Tables 1 and 2.
3.3.3. Cp2ZrH{(l-H)2BHPh} (3)
Method 1. In the drybox, 899 mg (2.0 mmol) of
Cp2Zr{(l-H)2BHPh}2 Æ (1/2 toluene) was charged into
a flask. The flask was evacuated, and 20 ml of toluene
was condensed to the flask at ꢀ78 ꢀC. A 0.28 ml (2.0
mmol) of N(C2H5)3 was measured and transferred to
the flask at ꢀ78 ꢀC. The flask was warmed to room tem-
perature and continued to stir for 4 h. The cloudy solu-
tion turned clear after stirring at room temperature for
few minutes. After the reaction the toluene was removed
and the resulting white solid was dissolved in the diethyl
ether and kept at ꢀ35 ꢀC for crystallization. Both com-
pounds, Cp2ZrH{(l-H)2BHPh} and (C2H5)3N Æ BH2Ph,
were crystallized and they were isolated through manual
separation and repeated recrystallization. A 455 mg
(72.6% yield) of Cp2ZrH{(l-H)2BHPh} and a 289 mg
(75.6% yield) of (C2H5)3N Æ BH2Ph were obtained.
Method 2. A 234.9 mg (2.4 mmol) of LiBH3Ph and
515 mg (2.0 mmol) of Cp2ZrHCl were charged to a flask
covered with aluminum foil. The flask was evacuated
and about 20 ml of toluene was condensed into the flask
at ꢀ78 ꢀC. The system was warmed to room tempera-
ture and stirred overnight. The LiCl was removed
through filtration and an oily species was obtained after
removal of the solvent under vacuum. The oily species
was allowed to stand at room temperature for days
and a 60 mg (9.6% yield) of colorless crystals was ob-
tained. Analysis data for Cp2ZrH{(l-H)2BHPh}: 11B
NMR (toluene): d 17.40 ppm (q, JB–H = 75 Hz). 1H
NMR (C6D6): d 7.48–7.10 (m, 5H, Ph), 5.53 (s, 10H,
Cp), 4.48 (s, 1H, ZrH), and ꢀ0.42 ppm (br, 3H, BH3).
IR(KBr): 3102(w), 3063(w), 3003(w), 2964(w),
2774(vw), 2394(m), 2346(w), 2265(vw), 2173(vw),
2033(w), 2008(w), 1962(m), 1924(m), 1920(m),
3.3. Preparation of complexes
3.3.1. Cp2ZrCl{(l-H)2BHPh} (1)
Cp2ZrCl2 (438 mg, 1.50 mmol) and LiBH3Ph (152
mg, 1.55 mmol) were charged to a flask in the drybox.
The flask was evacuated and 20 ml of the diethyl
ether was condensed to the flask at ꢀ78 ꢀC. The sys-
tem was warmed to room temperature and stirred
overnight. The LiCl formed was separated from the
solution through filtration. A white solid was obtained
after removal of the solvent from the filtrate. Colorless
crystals of 1 (438 mg, 84% yield) were obtained after
crystallization in Et2O at ꢀ35 ꢀC. 11B NMR (d8-
THF): d 2.37 ppm (q, JB–H = 76 Hz). 1H NMR (d8-
THF): d 7.27–6.29 (m, 5H, Ph), 6.32 (s, 10H, Cp),
and 1.00 ppm (br, 3H, BH3). IR(KBr): 3110(m),
3087(vw), 3065(vw), 3050(vw), 3011(vw), 2953(vw),
2924(vw), 2855(vw), 2692(vw), 2400(w), 2366(w),
2348(vw), 2271(vw), 2185(vw), 2087(m), 1992(w),
1936(vw), 1439(m), 1436(m), 1345(s), 1305(m),
1279(m), 1263(m), 1185(w), 1156(vw), 1126(vw),
1092(m), 1070(w), 1014(m), 926(vw), 826(vs),
770(vw), 720(s), 700(m), 671(vw), 651(vw), 610(vw),
581(vw), 548(vw), and 471(vw) cmꢀ1. Anal. Calc. for
C16H18BClZr: C, 55.25; H, 5.22. Found: C, 55.52;
H, 5.14%.

F.-C. Liu et al. / Journal of Organometallic Chemistry 690 (2005) 291–300
299
1912(m), 1597(br, m), 1432(m), 1420(m), 1396(s),
1389(s), 1261(m), 1181(m), 1088(s), 1066(m), 1028(m),
1014(s), 915(vw), 812(vs), 716(s), 698(m), 653(w),
583(w), and 458(vw) cmꢀ1. Anal. Calc. for C16H19BZr:
C, 61.33; H, 6.11. Found: C, 61.42; H, 6.06%. Analysis
data for (C2H5)3N Æ BH2Ph: 11B NMR (toluene): d
ꢀ6.78 ppm (t, JB–H = 97 Hz). 1H NMR (C6D6): d
7.81–7.29 (m, 5H, Ph), 2.86 (br, q, 2H, BH2), 2.22 (q,
6H, CH2, JH–H = 7.3 Hz), and 0.74 ppm (t, 9H, CH3,
JH–H = 7.3 Hz). IR(KBr): 3080(vw), 3064(w), 3045(w),
2999(s), 2976(m), 2943(w), 2912(w), 2877(w), 2816(vw),
2418(w), 2349(br, vs), 2295(m), 2276(w), 2256(w),
2210(vw), 2191(vw), 2092(vw), 1560(vw), 1475(m),
1460(m), 1452(m), 1444(w), 1429(w), 1414(vw),
1381(s), 1356(w), 1340(vw), 1261(vw), 1198(s),
1173(m), 1151(s), 1126(w), 1107(s), 1088(m), 1068(w),
1055(w), 1034(m), 1011(m), 993(w), 904(vw), 889(vw),
854(vw), 823(vw), 800(vw), 776(m), 760(m), 737(s),
708(s), 638(m), and 449(vw) cmꢀ1. Anal. Calc. for
C12H22BN: C, 75.41; H, 11.60; N, 7.33. Found: C,
75.05; H, 11.50; N, 7.30%.
3001(w), 2987(w), 2947(vw), 2908(vw), 2873(vw),
2366(br, m), 2339(w), 2027(vw), 1863(vw), 1776(vw),
1639(s), 1601(w), 1550(w), 1512(s), 1460(br, vs),
1390(m), 1375(m), 1321(w), 1273(s), 1184(w), 1115(s),
1101(s), 1072(s), 1014(m), 970(vs), 906(m), 879(w),
825(s), 754(s), 723(m), 685(vw), 654(m), 602(w),
563(w), 521(w), 469(vw), and 409(vw) cmꢀ1 Anal. Calc.
for C32H21BClF15OZr: C, 45.54; H, 2.51. Found: C,
45.60; H, 2.49%.
3.3.6. Cp2Ti{(l-H)2BHPh} (6)
In the drybox, 470 mg (4.8 mmol) of LiBH3Ph and
500 mg (2.0 mmol) of Cp2TiCl2 were charged to a flask.
The flask was evacuated and about 20 ml of diethyl
ether was condensed to the flask at ꢀ78 ꢀC. The system
was warmed to room temperature and stirred for 6 h.
During the reaction, H2 gas evolved and the solution be-
came purple in color. The LiCl was removed by filtra-
tion and the volatile materials were removed under
vacuum. The purple solid left in the flask was dissolved
in Et2O and kept at ꢀ35 ꢀC for crystallization. A 518 mg
(96.3% yield) of purple crystals were obtained. 11B
1
3.3.4. Reaction of Cp2ZrCl{(l-H)2BHPh} with B(C6F5)3
in toluene
NMR (d8-THF): not observed. H NMR (d8-THF): d
7.68(br, s), 6.89(s), and 6.55(s) ppm. IR(KBr):
3117(vw), 3091(vw), 3066(w), 3045(vw), 2999(w),
2969(vw), 2928(vw), 2029(vw), 2003(w), 1911(m),
1896(m), 1820(w), 1804(w), 1431(m), 1389(vs),
1365(m), 1343(w), 1309(w), 1263(w), 1176(w), 1156(w),
1120(w), 1064(w), 1015(s), 997(w), 916(vw), 906(vw),
819(m), 804(vs), 779(w), 739(m), 710(s), 666(vw),
604(w), 558(w), 487(vw), and 436(vw) cmꢀ1. Anal. Calc.
for C16H18BTi: C, 71.44; H, 7.74. Found: C, 71.66; H,
7.63%.
In the drybox, 347.8 mg (1.00 mmol) of Cp2ZrCl{(l-
H)2BHPh} and 342.0 mg (0.67 mmol) of B(C6F5)3 were
charged into a 50 ml flask. The flask was evacuated and
20 ml of the toluene was condensed to the flask at ꢀ78
ꢀC. The flask was warmed to room temperature and
continued to stir overnight. The solution was separated
from the solids through filtration and the solids were
washed with two portions of 20 ml of toluene. The solu-
tion were combined and white solids were obtained after
removal of the volatile species. Several crystals of
Cp2ZrCl{(l-H)2B(C6F5)2} were obtained from a hex-
ane/toluene mixed solvent system. 11B NMR (toluene):
d ꢀ10.6 ppm (t, JB–H = 67 Hz). 1H NMR (C6D6): d
5.63 (s, 10H, Cp) and 0.38 ppm (br, q, 2H, BH2).
Acknowledgement
This work was supported by the National Science
Council of the ROC through Grant NSC 92-2113-M-
259-007.
3.3.5. [Cp2ZrCl(OC4H10)][HB(C6F5)3] (5)
Cp2ZrCl{(l-H)2BHPh}, (347.8 mg, 1.0 mmol) and
B(C6F5)3 (512.0 mg, 1.0 mmol) were charged into a flask
in the drybox. The flask was evacuated and 15 ml of
diethyl ether was condensed to the flask at ꢀ78 ꢀC.
The system was warmed to room temperature gradually
and stop stirring after a clear solution was formed. Pale
yellow-green crystals were grown gradually. After stand-
ing at room temperature for 10 h, the crystals of
[Cp2ZrCl(OC4H10)][HB(C6F5)3] were separated from
the solution through filtration. These crystals were
washed with two portions of 10 ml ether and were dried
under vacuum. A 674.0 mg (79.9% yield) of pale yellow-
green crystals was obtained. 11B NMR (THF): d ꢀ25.9
Appendix A. Supplementary material
Crystallographic data for the structural analysis have
been deposited with the Cambridge Crystallographic
Data Center, CCDC Nos. 238550 (compound 1),
238551 (compound 2), 238552 (compound 3), 238553
(compound 4), 238554 (compound 5), 238555 (com-
pound 6), Copies of this information may be obtained
free of charge from The Director, CCDC, 12 Union
Road, Cambridge CB2 1EZ, UK (fax: +44 1223
336033; e-mail: deposit@ccdc.cam.ac.uk or www:
http://www.ccdc.cam.ac.uk). Supplementary data asso-
ciated with this article can be found, in the online
version at doi:10.1016/j.jorganchem.2004.09.026.
1
ppm (q, JB–H = 93 Hz). H NMR (d8-THF): d 6.85 (s,
10H, Cp), 3.80 (br, q, 1H, BH), 3.38 (q. 2H, CH2),
1.11 ppm (t, 3H, CH3). IR(KBr): 3123(m), 3095(w),

300
F.-C. Liu et al. / Journal of Organometallic Chemistry 690 (2005) 291–300
[11] (a) B. Singaram, T.E. Cole, H.C. Brown, Organometallics 3
(1984) 774;
References
(b) W. Biffar, H. No¨th, D. Sedlak, Organometallics 2 (1983) 579.
[12] F.-C. Liu, B. Du, J. Liu, E.A. Meyers, S.G. Shore, Inorg. Chem.
38 (1999) 3228.
[1] (a) T.J. Marks, J.R. Kolb, Chem. Rev. 77 (1977) 263;
(b) K.B. Gilbert, S.K. Boocock, S.G. Shore, Compounds with
bonds between a transition metal and boron, in: G. Wilkinson,
F.G.A. Stone, E.W. Abel (Eds.), Comprehensive Organometallic
Chemistry, Pergamon Press Inc., New York, 1982, pp. 879–945;
(c) L. Barton, D.K. Srivastava, Metallaboranes, in: G. Wilkinson,
E.W. Abel, F.G.A. Stone (Eds.), Comprehensive Organometallic
Chemistry, Pergamon Press Inc., New York, 1995, pp. 275–372;
(d) M. Ephritikhine, Chem. Rev. 97 (1997) 2193.
[2] (a) F.-C. Liu, K.-Y. Chen, J.-H. Chen, G.-H. Lee, S.-M. Peng,
Inorg. Chem. 42 (2003) 1758;
[13] P.T. Wolczanski, J.E. Bercaw, Organometallics 1 (1982) 793.
[14] R.E. von H. Spence, D.J. Parks, W.E. Piers, M.-A. MacDonald,
M.J. Zaworotko, S.J. Rettig, Angew. Chem., Int. Ed. Engl. 34
(1995) 1230.
[15] F.-C. Liu, J. Liu, E.A. Meyers, S.G. Shore, J. Am. Chem. Soc.
122 (2000) 6106.
ˇ
[16] F.-C. Liu, C.E. Plecnik, S. Liu, J. Liu, E.A. Meyers, S.G. Shore,
J. Organomet. Chem. 627 (2001) 109.
[17] J.W. Lauher, R. Hoffmann, J. Am. Chem. Soc. 98 (1976) 1729.
(b) W.K. Kot, N.M. Edelstein, A. Zalkin, Inorg. Chem. 26 (1987)
1339;
´
[18] B. Sztaray, E. Rosta, Z. Bo¨cskey, L. Szepes, J. Organomet.
Chem. 582 (1999) 267.
(c) R. Shinomoto, E. Gamp, N.M. Edelstein, D.H. Templeton,
A. Zalkin, Inorg. Chem. 22 (1983) 2351;
[19] P.L. Johnson, S.A. Cohen, T.J. Marks, J.M. Williams, J. Am.
Chem. Soc. 100 (1978) 2709.
(d) R. Shinomoto, A. Zalkin, N.M. Edelstein, Inorg. Chem. Acta
139 (1987) 97;
[20] The B–Zr–B angles of other metallocene hydroborate disubsti-
tuted compounds were not reported.
(e) J. Brennan, R. Shinomoto, A. Zalkin, N.M. Edelstein, Inorg.
Chem. 23 (1984) 4143;
[21] R.W. Broach, I.-S. Chuang, T.J. Marks, J.M. Williams, Inorg.
Chem. 22 (1983) 1081.
(f) R. Shinomoto, A. Zalkin, N.M. Edelstein, D. Zhang, Inorg.
Chem. 26 (1987) 2868;
[22] (a) G.T. Jordan IV, S.G. Shore, Inorg. Chem. 35 (1996) 1087;
(b) G.T. Jordan IV, F.-C. Liu, S. Shore, J. Inorg. Chem. 36 (1997)
5597.
(g) R. Shinomoto, J. Brennan, N.M. Edelstein, A. Zalkin, Inorg.
Chem. 24 (1985) 2896.
[23] W.J. Highcock, R.M. Mills, J.L. Spencer, P. Woodward, J.
Chem. Soc., Dalton Trans. (1986) 821.
[3] (a) J.C. Bommer, K.W. Morse, Inorg. Chem. 22 (1983) 592;
(b) J.C. Bommer, K.W. Morse, Inorg. Chem. 18 (1979) 531;
(c) J.C. Bommer, K.W. Morse, Inorg. Chem. 19 (1980) 587.
[4] (a) D.G. Holah, A.N. Hughes, N.I. Khan, Can. J. Chem. 62
(1984) 1016;
[24] S.B. Stones, J.L. Peterson, Inorg. Chem. 20 (1981) 2889.
[25] M.B. Fischer, E.J. James, T.J. McNeese, S.C. Nyburg, B. Posin,
W. Wong-Ng, S.S. Wreford, J. Am. Chem. Soc. 102 (1980) 4941.
[26] (a) W.A. Howard, G. Parkin, J. Am. Chem. Soc. 116 (1994) 606;
(b) W.A. Howard, M. Waters, G. Parkin, J. Am. Chem. Soc. 115
(1993) 4917.
(b) B.G. Segal, S.J. Lippard, Inorg. Chem. 16 (1977) 1623;
(c) K.M. Melmed, T.-I. Li, J.J. Mayerle, S.J. Lippard, J. Am.
Chem. Soc. 96 (1974) 69;
[27] (a) K.M. Melmed, D. Coucouvanis, S.J. Lippard, Inorg. Chem.
12 (1973) 232;
(d) R. Hedelt, C. Schulzke, D. Rehder, Inorg. Chem. Commun. 3
(2000) 300.
(b) G.I. Mamaeva, I. Hargittai, V.P. Spiridonov, Inorg. Chim.
Acta 25 (1977) L123.
[5] P. Paetzold, L. Geret, R. Boese, J. Organomet. Chem. 381 (1990)
1.
[28] DENZO-SMN Z. Otwinowsky, W. Minor, Processing of X-ray
diffraction data collected in oscillation mode, in: C.W. CarterJr.,
R.M. Sweet (Eds.), Methods in Enzymology, vol. 276: Macromo-
lecular Crystllography, Part A, Academic Press, New York, 1997,
pp. 307–326.
[6] (a) R.K. Nanda, M.G.H. Wallbridge, Inorg. Chem. 3 (1964)
1798;
(b) B.D. James, R.K. Nanda, M.G.H. Wallbridge, Inorg.
Chem. 6 (1967) 1979.
[7] F.-C. Liu, J. Liu, E.A. Meyers, S.G. Shore, Inorg. Chem. 37
(1998) 3293.
[8] The closest non-bonded contact distance of the phenyl group with
[29] (a) R.H. Blessing, Acta Crystallogr. Sect. A 51 (1995) 33;
(b) R.H. Blessing, J. Appl. Crystallogr. 30 (1997) 421–426.
[30] SHELXS-97 G.M. Sheldrick, Acta Crystallogr., Sect. A 46 (1990)
467.
˚
other atoms is 3.405 A in C(1A)—(13).
[9] R.E. von H. Spence, W.E. Piers, Y. Sun, M. Parvez, L.R.
MacGillivray, M.J. Zaworotko, Organometallics 17 (1998) 2459.
[10] J. Liu, E.A. Meyers, S.G. Shore, Inorg. Chem. 37 (1998) 496.
[31] G.M. Sheldrick, SHELXL-97, University of Go¨ttingen: Go¨ttingen,
Germany, 1997.