Bis(?5:?1-pentafulvene)titanium complexes: Catalysts for intramolecular alkene hydroamination and reagents for selective reactions with N'H acidic substrates

Article abstract of DOI:10.1021/om100056q

Intramolecular catalytic hydroamination reactions of geminally disubstituted amino alkenes employing the bulky substituted bis(? ⁵:?¹-pentafulvene)titanium complexes 1a and 1b and the corresponding benzannelated derivative 2 as catalysts are presented. While all three complexes are competent hydroamination catalysts, best results are achieved with the bis(benzofulvene) derivative 2. In addition, a series of Ti'N-containing compounds became available by stoichiometric reactions of 1 with N'H acidic substrates. In such a way, using aniline derivates (H ₂N'Ar, Ar: p-tolyl, 1-naphthyl) the bisamides (?⁵-C ₅H₄'CHR₂)₂Ti(NHAr)₂ (CHR₂: adamantyl, Ar: p-tolyl 5a; R: p-tolyl, Ar: p-tolyl 5b; R: p-tolyl, Ar: 1-naphthyl 5c; CHR₂: adamantyl, Ar: 1-naphthyl 5d) are prepared in high yields under mild conditions. In contrast to this, the employment of the catalytically relevant amine H₂NCH ₂C(Ph)₂CH₂CH-CH₂ (3a) in a reaction with (?⁵:?¹-C₅H₄-CR ₂)₂Ti (CR₂: adamantylidene, 1a) leads to the titanium monoamide (?⁵:?¹-C₅H ₄-CR₂)(?⁵-C₅H₄'CHR ₂)Ti(NHCH₂C(Ph)₂CH₂CH-CH ₂) (6), characterized by X-ray diffraction. In reaction of 1a and 1b with benzophenone imine the titanocene bis(enamides) (?⁵-C ₅H₄'CHR₂)₂Ti(N-CPh₂) ₂ 7a and 7b are formed. Titanium nitrogen double bonds are formed by treatment of 1a with 1,1-diphenylhydrazine. In that manner the hydrazido titanocene (?⁵-C₅H₄'CHR₂) ₂Ti-N'N(Ph)₂ (CHR₂: adamantyl) was structurally characterized as the pyridine adduct 9. Three different Ti'N bonds are formed in one step by reaction of (?⁵:?¹-C₅H ₄-CR₂)₂Ti (R: p-tolyl, 1b) with 1,1-diphenylhydrazine and pyridine (py), leading to (?⁵-C ₅H₄'CHR₂)Ti(-N'NPh₂)('N'NPh ₂)py 10b (dative Ti'N bond: Ti'py 2.211(2) ?, single Ti'N bond: Ti'NNPh₂^' 1.968(2) ?, double Ti'N bond: Ti'NNPh ₂^2' 1.738(1) ?). The formation of 10b is accompanied by the liberation of one C₅H₅CHR₂ ligand. Generally, the bis(?⁵:?¹-pentafulvene)titanium complexes 1 and 2 are valuable catalysts in hydroamination reactions and reagents in order to prepare Ti'N-containing metallocene-type derivatives.

Full text of DOI:10.1021/om100056q

1806 Organometallics 2010, 29, 1806–1817
DOI: 10.1021/om100056q
Bis(η5:η1-pentafulvene)titanium Complexes: Catalysts for
Intramolecular Alkene Hydroamination and Reagents for Selective
Reactions with N-H Acidic Substrates†
ꢀ
Thomas Janssen, Rene Severin, Mira Diekmann, Marion Friedemann, Detlev Haase,
€
Wolfgang Saak, Sven Doye,* and Rudiger Beckhaus*
Institute of Pure and Applied Chemistry, Carl von Ossietzky University Oldenburg, D-26111 Oldenburg,
Germany
Received January 22, 2010
Intramolecular catalytic hydroamination reactions of geminally disubstituted amino alkenes
employing the bulky substituted bis(η5:η1-pentafulvene)titanium complexes 1a and 1b and the
corresponding benzannelated derivative 2 as catalysts are presented. While all three complexes are
competent hydroamination catalysts, best results are achieved with the bis(benzofulvene) derivative
2. In addition, a series of Ti-N-containing compounds became available by stoichiometric reactions
of 1 with N-H acidic substrates. In such a way, using aniline derivates (H2N-Ar, Ar: p-tolyl, 1-
naphthyl) the bisamides (η5-C5H4-CHR2)2Ti(NHAr)2 (CHR2: adamantyl, Ar: p-tolyl 5a; R: p-tolyl,
Ar: p-tolyl 5b; R: p-tolyl, Ar: 1-naphthyl 5c; CHR2: adamantyl, Ar: 1-naphthyl 5d) are prepared in
high yields under mild conditions. In contrast to this, the employment of the catalytically relevant
amine H2NCH2C(Ph)2CH2CHdCH2 (3a) in a reaction with (η5:η1-C5H4dCR2)2Ti (CR2: adaman-
tylidene, 1a) leads to the titanium monoamide (η5:η1-C5H4dCR2)(η5-C5H4-CHR2)Ti(NHCH2-
C(Ph)2CH2CHdCH2) (6), characterized by X-ray diffraction. In reaction of 1a and 1b with
benzophenone imine the titanocene bis(enamides) (η5-C5H4-CHR2)2Ti(NdCPh2)2 7a and 7b are
formed. Titanium nitrogen double bonds are formed by treatment of 1a with 1,1-diphenylhydrazine.
In that manner the hydrazido titanocene (η5-C5H4-CHR2)2TidN-N(Ph)2 (CHR2: adamantyl) was
structurally characterized as the pyridine adduct 9. Three different Ti-N bonds are formed in one
step by reaction of (η5:η1-C5H4dCR2)2Ti (R: p-tolyl, 1b) with 1,1-diphenylhydrazine and pyridine
(py), leading to (η5-C5H4-CHR2)Ti(dN-NPh2)(-N-NPh2)py 10b (dative Ti-N bond: Ti-py
-
2.211(2) A, single Ti-N bond: Ti-NNPh2 1.968(2) A, double Ti-N bond: Ti-NNPh22- 1.738(1)
ꢀ
˚
ꢀ
˚
ꢀ
˚
A). The formation of 10b is accompanied by the liberation of one C5H5CHR2 ligand. Generally, the
bis(η5:η1-pentafulvene)titanium complexes 1 and 2 are valuable catalysts in hydroamination reac-
tions and reagents in order to prepare Ti-N-containing metallocene-type derivatives.
Introduction
case of early transition metals by reaction of TiCl3 3thf
3
with Mg in the presence of bulky substituted pentafulvenes
(Fv).3
Metallocene derivatives of the early transition metals of
the type Cp2M(CR3)2 (A, M: Ti, Zr, Hf) are well-known
complexes for a large number of catalytic as well as stoichio-
metric transformations of many substrates.1,2 By formal
combination of the Cp anion with the σ-bonded carbon
ligand, bis(pentafulvene)metal complexes B become avail-
able (Scheme 1). These complexes can be synthesized in the
In such a way the bulky substituted bis(pentafulvene)- 1,
and bis(benzofulvene)titanium complexes 2 can be obtained
in high yields (Scheme 2).3
The bonding situation of the bis(fulvene)titanium com-
plexes 1 is best described as a π-η5:σ-η1 coordination mode.4
Due to the general strong nucleophilic character of the
exocyclic carbon in the pentafulvene complexes (Cexo) of
early transition metals, subsequent reactions with electro-
philes are found under comparably mild conditions. While
Cp2Ti(CH3)2 itself is stable against electrophiles (e.g., water)
at room temperature,5,6 fulvene complexes 1 and 2 show
significantly higher reactivity, even at -78 °C. Such reaction
patterns are observed for fulvene titanium derivatives in
† Dedicated to Prof. Dr. Uwe Rosenthal on the occasion of his 60th
birthday.
*Corresponding authors. (S.D.) Phone: þ49 441 798 3888. E-mail:
doye@uni-oldenburg.de. (R.B.) Phone: þ49 441 798 3656. Fax: þ49 441
798 3851. E-mail: ruediger.beckhaus@uni-oldenburg.de.
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Togni, A.; Manners, I., Metallocenes; Wiley-VCH: Weinheim, 1998.
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pubs.acs.org/Organometallics
Published on Web 03/05/2010
2010 American Chemical Society

Article
Scheme 1. Bentmetallocenes vs Bis(pentafulvene)metal
Complexes
Organometallics, Vol. 29, No. 7, 2010 1807
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1808 Organometallics, Vol. 29, No. 7, 2010
Janssen et al.
Scheme 4. Originally Proposed Catalytic Cycle of Ti-Catalyzed
Intramolecular Hydroamination Reactions of Alkenes60
However, on the basis of experimental findings75 as well as
computational studies,76 alternative mechanisms for the
group IV metal-catalyzed intramolecular hydroamination
of alkenes have recently been proposed. For example, Stub-
bert and Marks have suggested that the rate-limiting step of
the catalytic cycle of the group IV metal-catalyzed cycliza-
tion of aminoalkenes is an insertion of the alkene moiety into
a group IV metal amido bond of a simple amido complex.75
Although a similar mechanism is operative in rare-earth-
metal-catalyzed hydroamination reactions,77-80 it is also
possible that metal imido amido complexes are the catalyti-
cally active species.76 However, the formation of such species
from common catalyst precursors such as Cp2TiMe2 or
Ind2TiMe2 (Ind: η5-indenyl) must involve a possible loss of
one of the Cp (or Ind) ligands.81 With regard to the ongoing
discussion of the mechanistic details of Ti-catalyzed alkene
hydroamination the isolation of intermediates of the cataly-
tic cycle seems to be inevitable. However, most mechanistic
investigations and especially studies dealing with the isola-
tion or the synthesis of possible intermediates of a catalytic
cycle are performed under conditions and with starting
materials or catalyst precursors that are different from those
applied during the original reaction. Interestingly, our bis-
(fulvene)titanium complexes 1 and 2 (Scheme 2) are very
reactive even at room temperature, which is in sharp contrast
to most of the extensively used hydroamination precatalysts
(e.g., Cp2TiMe2, Ind2TiMe2), which need high temperatures
to react with amines.31,39,53 On the basis of this fact, we
decided to use the bis(fulvene)titanium complexes 1 and 2 as
tools for studying some mechanistic details of the Ti-cata-
lyzed intramolecular hydroamination of alkenes. Herein, we
present the catalytic application of 1 and 2 in hydroamina-
tion reactions of aminoalkenes as well as stoichiometric
reactions of 1 with amines, imines, and hydrazines. In
addition, some hints are discussed concerning the alternative
insertion mechanism75 as well as the possible loss of one Cp
ligand during the catalytic reaction.81
limited to the cyclization of aminoalkenes.59-73 In the case of
titanium-catalyzed reactions of alkynes, imido intermediates
are generally accepted to be the catalytically active species.74
These react with an alkyne in a [2þ2]-cycloaddition via a
precoordinated species41 to give an azatitanacyclobutene.
The azatitanacyclobutene then reacts with additional amine
to a bisamide, which finally liberates the hydroamination
product and regenerates the catalytically active imido spe-
cies. On the basis of this knowledge, it was initially proposed
that the intramolecular hydroamination of alkenes per-
formed with neutral titanium catalysts takes place by a
corresponding [2þ2]-cycloaddition mechanism (Scheme 4)
that involves the imido intermediate II as the catalytically
active species.60
Results and Discussion
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Article
Organometallics, Vol. 29, No. 7, 2010 1809
Table 1. Synthesis of Pyrrolidines by Intramolecular Hydroamination
a Reaction conditions: (1) amino alkene (2.40 mmol), catalyst (0.12 mmol, 5 mol %), toluene (2.0 mL), 105 °C, 24 h; (2) BzCl (2.64 mmol), NEt3 (7.2
mmol), CH2Cl2 (10 mL), 25 °C, 12 h. Yields refer to the isolated pure compounds.
substituents at the alkyl tether. While the reaction of this less
Thorpe-Ingold-activated substrate still went to completion
within 24 h at 105 °C in the presence of the bis(benzofulvene)-
titanium complex 2, the use of the bis(pentafulvene)titanium
complexes 1a and 1b led to only 68% and 70% conversion,
respectively. Correspondingly, the pyrrolidine product 4b
was obtained in good yield (93%) from the reaction per-
formed in the presence of 2, while only modest yields (58%
and 61%) were reached with the catalysts 1a and 1b. These
results as well as the fact that the simple bis(indenyl)titanium
complex Ind2TiMe2 is a catalytically more active hydroami-
nation catalyst than the corresponding bis(cyclopentadi-
the nonvolatile benzamides 4c and 4d could be isolated in
70% and 18% yield, respectively.
Reactions with Amines. As shown, the bis(pentafulvene)- 1
and bis(benzofulvene)titanium 2 complexes are active hydro-
amination catalysts. We decided to use 1 in subsequent
reactions with N-H acidic compounds due to the better
crystallization tendency of the reaction products. Reacting 1
with aniline derivatives at room temperature, a fast color
change from green to red occurs. The crystalline titanocene
amides 5 are obtained in yields from 41% (5a) to 61% (5b).
They are easily soluble in benzene, toluene, and thf and
moderately soluble in n-hexane. Solid 5 reacts very slowly if
exposed to air, although solutions degrade faster. The pri-
mary expected imido derivates C (Scheme 3) are never
observed, not even using different stoichiometries or pyri-
dine as trapping agent.82
39
enyl)titanium complex Cp2TiMe2 suggest that the bis-
(benzofulvene)titanium complex 2 represents a more active
hydroamination catalyst than the bis(pentafulvene)titanium
complexes 1a and 1b. This hypothesis is strongly supported
by the fact that the less Thorpe-Ingold-activated substrates
3c and 3d (Table 1, entries 7-11) do not undergo any
cyclization at 105 °C in the presence of 1a or 1b, while under
identical reaction conditions, 2 is still able to convert these
substrates to the desired pyrrolidines. Due to the low boiling
points of the hydroamination products initially formed
from 3c and 3d, benzoyl chloride and NEt3 were added to
the crude reaction mixtures prior to isolation. Subsequently,
However, as expected, the nucleophilic Cexo fulvene atoms
are protonated first by the amine to form the corresponding
substituted CpR derivates 5, as shown in Scheme 5. The 1H
NMR spectra of 5a-d show characteristic signals of the NH
unit between 7.39 (5a) and 8.72 ppm (5c) as a broadened
(82) Dunn, S. C.; Mountford, P.; Robson, D. A. J. Chem. Soc.,
Dalton Trans. 1997, 293–304.

1810 Organometallics, Vol. 29, No. 7, 2010
Janssen et al.
Scheme 5. Reactions of 1 with Primary Anilines
Table 2. Selected 1H NMR Data [δ, ppm] (C6D6, 500.13 MHz,
300 K) of 5a-d
5a
5b
5c
5d
CHR2
Ar
C5H4
adamantyl
p-tolyl
5.64
6.06
7.39
R = p-tolyl
p-tolyl
5.13
5.88
7.84
R = p-tolyl
1-naphthyl
5.61
6.06
8.72
adamantyl
1-naphthyl
5.70
6.10
8.30
Figure 1. ORTEP plot of the solid-state molecular structure of
˚
5a (50% probability ellipsoids). Selected bond lengths (A) and
NH
angles (deg): Ti1-N1 2.0127(13), Ti1-N2 2.0101(13), Ti1-Ct1
2.122, Ti1-Ct2 2.127, N1-C1 1.392(2), N2-C8 1.399(2), C15-
C20 1.534(2), C30-C35 1.5206(18), Ti1-C15 2.4835(15), Ti1-
C16 2.4650(15), Ti1-C17 2.4240(16), Ti1-C18 2.3801(16),
Ti1-C19 2.4442(16), Ti1-C30 2.5218(13), Ti1-C31 2.4474(15),
Ti1-C32 2.3701(16), Ti1-C33 2.4028(16), Ti1-C34 2.4699(15),
C15-C19 1.415(2), C15-C16 1.434(2), C16-C17 1.402(2),
C17-C18 1.413(2), C18-C19 1.417(2), C30-C31 1.411(2),
C30-C34 1.426(2), C31-C32 1.414(2), C32-C33 1.406(2),
C33-C34 1.404(2), C1-N1-Ti1 133.27(10), C8-N2-Ti1
135.19(10), N2-Ti1-N1 95.33(6), Ct-Ti1-Ct 128.2; Ct1 =
centroid of C15-C19; Ct2 = centroid of C30-C34. Hydrogen
atoms are omitted for clarity.
singlets (Table 2). Of high diagnostic value in the formation
of 5 are the two signals for the C5H4 fragment in the expected
range (Table 2), in contrast to the four singlets for the
C5H4dCR2 ligands in 1. Additionally, characteristic singlets
are found at 5.30 (5b) and 5.42 ppm (5c) for the CexoH proton
if bistolylfulvene is used. The corresponding signals for the
adamantyl derivates are found in the expected range. The
complexes 5a-d do not give an Mþ signal in the mass
spectrum (neither CI nor EI mode).
Dark red crystals of 5 suitable for X-ray structure deter-
mination can be obtained at room temperature from a
saturated n-hexane solution. Due to the similarities of the
molecular structures of 5a-d, only 5a is given in Figure 1.83
Selected bond distances and angles of 5a-d are summarized
in Table 3.
˚
Table 3. Selected Bond Lengths [A] and Angles [deg] of 5a-d
5a
5b
5c
5da
CHR2
Ar
adamantyl
R = p-tolyl
R = p-tolyl
adamantyl
The titanocene amides 5a crystallize in the monoclinic
space group P21/n, 5b and 5c in P21/c, and 5d in the
orthorhombic space group Pbcn. The Ti(IV) atom has the
typical pseudotetrahedral coordination features when the
Ct-Ti-Ct (128°) and the N-Ti-N (95-98°) angles are
compared with other titanocene derivatives.84 The observed
p-tolyl
p-tolyl
1-naphthyl
1-naphthyl
Bond Lengths
Ti-N
2.010(1)
2.013(1)
1.392(2)
1.399(2)
2.122
2.008(3)
2.015(3)
1.399(5)
1.415(5)
2.122
2.021(4)
2.027(3)
1.403(5)
1.398(5)
2.116
2.041(2)
1.384(3)
2.102
˚
N-C
Ti-N bond lengths, 2.01 to 2.04 A, are in the expected range
for Ti-N single bonds without pπ-dπ interactions.85 If
pπ-dπ interactions become possible, depending on the
rotameric orientation of the Ti-NR2 unit, shorter Ti-N
Ti-Ctb
2.127
2.125
2.113
86
Bond Angles
˚
distances are found (CpTiCl2(NHt-Bu) 1.879(3) A;
87
CpTiCl2(Ni-Pr2) 1.865(2) A ). If the nitrogen lone pair is
˚
Ct-Ti-Ct
Ti-N-C
128.2
128.5
127.6
128.6
133.7(2)
133.3(1)
135.2(1)
95.3(1)
132.8(3)
133.8(3)
96.5(1)
136.5(3)
134.6(3)
94.5(2)
orientated perpendicular to the mirror plane of the metallo-
cene fragement,88,89 longer Ti-N distances are found (Cp2-
TiCl(C5H3N4) 2.131(5) A; Cp*2TiN(Me)Ph 2.054(2) A ).
90
88
N-Ti-N
98.2(1)
˚
˚
a Molecule on the dyadic axis. b Ct = centroid of Cp rings.
(83) Structural data of 5b, 5c, 5d, and 7b are given in the Supporting
Information.
(84) Cozak, D.; Melnik, M. Coord. Chem. Rev. 1986, 74, 53–99.
(85) Herrmann, W. A.; Denk, M.; Albach, R. W.; Behm, J.; Herdtweck,
E. Chem. Ber. 1991, 124, 683–689.
(86) Giolando, D. M.; Kirschbaum, K.; Graves, L. J.; Bolle, U. Inorg.
Chem. 1992, 21, 3887–3890.
(87) Pupi, R. M.; Coalter, J. N.; Petersen, J. L. J. Organomet. Chem.
1995, 497, 17–25.
(88) Feldman, J.; Calabrese, J. C. J. Chem. Soc., Chem. Commun.
In contrast to the reaction course of aniline derivates and
1, which leads to the bisamides 5, the reaction of bis-
(adamantylidenefulvene)titanium 1a with catalytically rele-
vant alkylamine 3a leads to the monoamide 6. Independent
from the stoichiometric conditions, 5 is formed in a selective
way, even if an excess of 3a is used. This reaction proceeds at
room temperature leading to the orange-red crystalline 6.
Surprisingly, only one fulvene ligand of 1a is protonated, to
give the mixed CpR-fulvene complex 6 (Scheme 6). The
formation of the monoamide 6, in contrast to the bisamides
5a-d, becomes understandable by the lower acidities of
1991, 1042–1044.
(89) Lukens, W. W., Jr.; Smith, M. R., III; Andersen, R. A. J. Am.
Chem. Soc. 1996, 118, 1719–1728.
(90) Beauchamp, A. L.; Cozak, D.; Mardhy, A. Inorg. Chim. Acta
1984, 92, 191–197.

Article
Organometallics, Vol. 29, No. 7, 2010 1811
Figure 3. Detail of the molecular structure of 6 (olefinic C-C
double bond green).
Scheme 7. Reaction of 1 with Benzophenone Imine
Figure 2. ORTEP plot of the solid-state molecular structure of
˚
6 (50% probability ellipsoids). Selected bond lengths (A) and
angles (deg): Ti1-N1 1.9386(15), Ti1-Ct1 2.019, Ti1-Ct2
2.058, Ti1-C18 2.1724(19), Ti1-C19 2.3324(18), Ti1-C20
2.472(2), Ti1-C21 2.464(2), Ti1-C22 2.3085(19), Ti1-C23
2.4034(19), Ti1-C33 2.4010(18), Ti1-C34 2.3824(18), Ti1-
C35 2.3682(19), Ti1-C36 2.376(2), Ti1-C37 2.3869(19), N1-
C1 1.460(2), C4-C5 1.314(4), C18-C19 1.438(3), C18-C22
1.453(3), C18-C23 1.434(3), C19-C20 1.410(3), C20-C21
1.406(3), C21-C22 1.391(3), C33-C34 1.417(3), C33-C37
1.423(3), C33-C38 1.514(3), C34-C35 1.418(3), C35-C36
1.403(3), C36-C37 1.403(3), C1-N1-Ti1 141.32(12), Ct1-
Ti1-Ct2 136.4; Ct1 = centroid of C18-C22; Ct2 = centroid
of C33-C37. Hydrogen atoms are omitted for clarity.
bond of the fulvene ligand in 6 is bent out of the five-
membered ring plane by 34.5°, as expected for titanium
fulvene complexes.3 The Ti-N-C angle (141.32(12)°) is
typical for an amidotitanium complex and comparable to 5
˚
(av 133-135°), although the Ti-N bond (1.9386(15) A) is
slightly shortened compared to the bisamides 5 (av 2.01-
˚
2.04 A). The C-C double bond of the amido alkenyl side
chaine in 6 is orientated in a suprafacial manner in the
direction of the titanium-nitrogen center (Figure 3). This
orientation can be explained on one hand by the Thor-
pe-Ingold effect of the phenyl groups on the amine 3a.92
On the other hand, the ligand geometry of 6 is in accordance
with the intermediate I in the catalytic hydroamination cycle
(Scheme 4). A second R-H-shift from the N atom in 6 to the
Scheme 6. Reaction of 1a with the Aminoalkene 3a
C
exo atom of the intact fulvene ligand would lead to the active
imido species (II or III). However, under experimental
conditions this rearrangement was not observable upon
heating to 60 °C for 5 h.
Reactions with Imines. The effect of the shortened Ti-N
bond can also be observed in the reaction products of 1 with
benzophenone imine in n-hexane at room temperature.
Again a fast reaction of 1 to 7 can be observed by the change
of color from green to dark red. Dark red crystals of 7 are
isolated in 74% (7a, mp 179 °C dec) and 54% (7b, mp 154 °C
dec) yield. Solid 7 can be handled without inert conditions in
the short-term, but solutions degrade faster, which is visible
by a change in color from red to yellow. The Cexo atoms are
protonated to give the CpR derivate and two N ligands are
bound, comparable to the bisamides 5 as shown in Scheme 7.
In the 1H NMR spectra two characteristic triplets (J = 2.6
Hz) of the CpR ligands at 5.47, 5.89 (7a) and 5.22, 5.76 ppm
(7b) are found. These values are in agreement with 5 (5.64,
6.06 (5a); 5.13, 5.88 (5b); 5.61, 6.06 (5c), and 5.70, 6.10 (5d)).
Again the typical new CexoH singlet for p-tolyl derivative 7b
is found at 5.56 ppm. Crystals suitable for X-ray structure
determination can be obtained directly from the reaction
solution after a few days at room temperature. The com-
plexes 7a,b do not give an Mþ signal in the mass spectrum
(neither CI nor EI mode). The molecular structure of 7a is
given in Figure 4 as an example, and selected bond distances
alkylamines compared with anilines.91 Isolated crystalline 6
is very sensitive to air and moisture, particularly in contrast
to the bisamides 5a-d. The monoamide 6 is easily soluble in
thf, benzene, toluene, and even n-hexane.
The 1H NMR spectrum shows four singlets for the proto-
nated fulvene ligand C5H4-Cp (5.05, 5.08, 5.72, 5.86 ppm),
whereas for the unchanged fulvene C5H4-Fv four singlets
(4.13, 5.24, 5.29, 5.99 ppm) are found. The NH singlet (6.15
ppm) is characteristically broadened. The complex 6 does
give an Mþ signal in the mass spectrum (CI mode, m/z (%):
681 (8)). The EI mode spectrum shows that in a primary step
the liberation of the amine 3a leads to an [M - C17H18N]þ
fragment (m/z: 445). Crystals of 6, suitable for X-ray struc-
ture determination, can be directly obtained from the reac-
tion mixture (benzene/n-hexane) after a few days at room
temperature. 6 crystallizes in the triclinic space group P1.
The molecular structure of 6 is given in Figure 2. The
adamantyle CpR fragment and the adamantylidenefulvene
ligand can easily be distinguished (Figure 2) comparing the
˚
C18-C23 fulvene bond (1.434(3) A) and the elongated
˚
C33-C38 distance (1.514(3) A). The exocyclic C-C double
(91) Habibi-Yangjeh, A.; Pourbasheer, E.; Danandeh-Jenagharad,
M. Monatsh. Chem. 2009, 140, 15–27.
(92) Beesley, R. M.; Ingold, C. K.; Thorpe, J. F. J. Chem. Soc., Trans.
1915, 107, 1080–1106.

1812 Organometallics, Vol. 29, No. 7, 2010
Janssen et al.
Table 4. Selected Bond Lengths [A] and Angles [deg] of 7a,b and 8
˚
7a
Bond Lengths
7b
893
Ti-N
N-C
1.957(2)
1.960(2)
1.260(3)
1.266(3)
1.945(1)
2.015(1)
1.272(2)
1.274(2)
1.901(2)
1.259(3)
Bond Angles
Ti-N-C
168.6(2)
168.4(2)
101.9(1)
135.1
164.8(1)
151.8(1)
101.2(1)
135.3
179.1(2)
N-Ti-N/C
Ct-Ti-Ct
96.41(8)
138.9
Scheme 8. Reaction of 1a with 1,1-Diphenylhydrazine
Figure 4. ORTEP plot of the solid-state molecular structure of
˚
7a (50% probability ellipsoids). Selected bond lengths (A) and
angles (deg): Ti1-N1 1.9573(18), Ti1-N2 1.9595(18), Ti1-Ct1
2.092, Ti1-Ct2 2.093, N1-C1 1.260(3), N2-C14 1.266(3),
Ti1-C27 2.453(2), Ti1-C28 2.423(2), Ti1-C29 2.376(2), Ti1-
C30 2.395(2), Ti1-C31 2.425(2), Ti1-C42 2.444(2), Ti1-C43
2.417(3), Ti1-C44 2.396(2), Ti1-C45 2.386(2), Ti1-C46
2.432(2), C27-C28 1.418(3), C27-C31 1.434(3), C27-C32
1.520(3), C28-C29 1.409(3), C29-C30 1.420(3), C30-C31
1.405(3), C42-C46 1.413(3), C42-C43 1.429(3), C42-47
1.530(3), C43-C44 1.407(3), C44-C45 1.417(4), C45-C46
1.416(3), C1-N1-Ti1 168.61(16), C14-N2-Ti1 168.36(16),
N1-Ti1-N2 101.89(7), N1-Ti1-C29 132.44(9), Ct1-Ti1-
Ct2 135.1; Ct1 = centroid of C27-C31; Ct2 = centroid of
C42-C46. Hydrogen atoms are omitted for clarity.
Reactions with Hydrazine. Whereas the desired TidN
double-bond-containing complexes are not available by
reaction of 1 with primary amines, the reaction of bis-
(adamantylidenefulvene)titanium 1a with 1,1-diphenylhy-
drazine is successful. Reacting 1a with 1,1-diphenylhydra-
zine and pyridine at room temperature in a benzene/
n-hexane mixture (1:2) as solvent, the titanium hydrazide
can be obtained as the pyridine adduct 9 (Scheme 8). The
reaction mixture turns instantly from green to red with the
1,1-diphenylhydrazine and does not change when the pyri-
dine is added. It is important to add the pyridine after the
hydrazine, because otherwise the pyridine reacts directly
with the bis(fulvene)complex 1, forming unknown products.
Again the Cexo atoms are both protonated, as shown in
Scheme 8, to give the CpR derivative, and the pyridine
saturates the coordination of the titanium center. After a
few days at 6 °C the product 9 crystallizes directly from the
reaction mixture in the form of brown-red crystals suitable
for X-ray structure determination. The molecular structure
is given in Figure 5. The titanium hydrazide 9 degrades
instantly with air or moisture even as a solid and is easily
soluble in benzene, toluene, and thf and moderately soluble
in n-hexane. However, in solution rearrangement processes
are observed, leading to the mono-Cp derivative 10 by a
liberation of one CpR ligand (vide infra). Therefore it was not
possible to obtain a representative 1H NMR spectra of 9. The
complex 9 does not give an Mþ signal in the mass spectrum
(neither CI nor EI mode).
are summarized in Table 4. 7a crystallizes in the monoclinic
space group P21/c and 7b in the triclinic space group P1. The
titanium center has the typical pseudotetrahedral coordina-
tion features with a Ct-Ti-Ct angle of 135° (7a 135.1°, 7b
135.2°) and a N-Ti-N angle of 102° (7a 101.9(1)°, 7b
101.2(1)°).
A comparable reaction pattern was observed by trapping a
titanaallene intermediate, Cp*2TidCdCH2, with benzophe-
none imine and formation of Cp*2Ti(CHdCH2)(N=CPh2)
(8). Generally, two different ligand motives of the imine
ligand are discussed, leading to azavinylidene (TidNdCR2)
or enamide (Ti-NdCR2) forms.93 To distinguish between
both forms, the Ti-N-C angle is the essential criterion. In
the case of the azavinylidene form a perfect Ti-N-C angle
of 180° is observed, e.g., in 8. In contrast, for 7 (7a 168.6° and
168.4°, 7b 164.8° and 151.8°) smaller angles are found.
9 crystallizes in the monoclinic space group P21/n. The
molecular structure of 9 (Figure 5) reveals a typical titanium
pseudotetrahedral coordination mode with a Ct-Ti-Ct angle
of 126.2° and a N-Ti-N angle of 92.42(6)°. The molecular
structure of 9 is clearly indicative for an end-on bonded
NNPh22- ligand. This structure motive is in contrast to side-on
hydrazido(1-) moieties95-97 as well as bridging coordination
˚
Additionally, the Ti-N bond length in 8 (1.90 A) is shorter
˚
˚
than in 7a (1.96 A) or in 7b (1.95/2.02 A). The N-C bonds
˚
(1.26-1.27 A) are in the range of typical NdC double bonds.
A similar bonding situation can be found for Cp2Ti-
(NCPh2)2.94 However, this complex is formed in a quite
different reaction, by a N-N bond cleavage of benzophe-
none azine.
(95) Hughes, D. L.; Leigh, G. J.; Walker, D. G. J. Chem. Soc., Dalton
Trans. 1989, 1413–1416.
(96) Latham, I. A.; Leigh, G. J.; Huttner, G.; Jibril, I. J. Chem. Soc.,
(93) Beckhaus, R.; Wagner, M.; Burlakov, V. V.; Baumann, W.;
Peulecke, N.; Spannenberg, A.; Kempe, R.; Rosenthal, U. Z. Anorg.
Allg. Chem. 1998, 624, 129–134.
Dalton Trans. 1986, 385–392.
(97) Goetze, B.; Knizek, J.; Noth, H.; Schnick, W. Eur. J. Inorg.
€
(94) Zippel, T.; Arndt, P.; Ohff, A.; Spannenberg, A.; Kempe, R.;
Rosenthal, U. Organometallics 1998, 17, 4429–4437.
Chem. 2000, 1849–1854.

Article
Organometallics, Vol. 29, No. 7, 2010 1813
Scheme 9. Reaction of 1b with Two Equivalents of
1,1-Diphenylhydrazine
[Cp2ZrdNNPh2(DMAP)]
(DMAP
=
dimethylami-
nopyridine).105 The N-N distance of 1.364(10) A versus
˚
˚
1.3534(18) A (9) is indicative of an N-N single bond (NtN:
106
107
˚
˚
1.0975(2) A,
PhNdNPh: 1.255 A,
Ph(H)N-N(H)Ph:
1.394(7) A108). However, the N-N distance in the Ph2NN2-
complexes is characterized by a weak shortening of the
N-N bond compared to free hydrazines (H2N-NH2:
˚
109
110
˚
˚
1.46 A, Ph2N-NPh2: 1.406(4) A,
Py(H)N-N(H)Py:
1.3934(14) A111).
˚
In the presence of two equivalents of Ph2NNH2 the
expected liberation of one CpRH ligand is observed, leading
to a monocyclopentadiene derivative 10 as shown in Scheme
9. When the solution of 1,1-diphenylhydrazine in n-hexane is
added to the solution of 1b in benzene, the reaction can
instantly be observed by the rapid change in color from green
to red. Again the pyridine has to be added after the hydra-
zine. After stirring for 70 h orange-red 10b can be isolated in
59% yield (mp 111 °C) by filtration. 10b degrades very fast
with air and moisture, visible in a color change from orange-
red to green (less dark than 1b) to light yellow, and is easily
soluble in benzene, toluene, and thf and moderately soluble
in n-hexane. 10a was obtained from a solution of 9 after
heating for a few minutes to 60 °C.
Figure 5. ORTEP plot of the solid-state molecular structure of
˚
9 (50% probability ellipsoids). Selected bond lengths (A) and
angles (deg): Ti1-Ct1 2.199, Ti1-Ct2 2.192, Ti1-N1
1.7567(13), Ti1-N3 2.2430(14), N1-N2 1.3534(18), N2-C1
1.401(2), N2-C7 1.438(2), Ti1-C18 2.6123(16), Ti1-C19
2.5239(17), Ti1-C20 2.3936(17), Ti1-C21 2.4582(17), Ti1-
C22 2.5399(16), Ti1-C332.4484(16), Ti1-C342.4480(17), Ti1-
C35 2.5419(17), Ti1-C36 2.5813(18), Ti1-C37 2.4734(17),
C18-C19 1.406(2), C18-C22 1.435(2), C18-C23 1.511(2),
C19-C20 1.416(3), C20-C21 1.413(3), C21-C22 1.401(2),
C33-C34 1.412(2), C33-C37 1.417(2), C33-C38 1.514(2),
C34-C35 1.416(3), C35-C36 1.392(3), C36-C37 1.416(2),
N1-Ti1-N3 92.42(6), N2-N1-Ti1 171.05(11), N1-N2-C1
121.99(13), N1-N2-C7 116.78(12), Ct1-Ti1-Ct2 126.2; Ct1 =
centroid of C18-C22; Ct2 = centroid of C33-C37. Hydrogen
atoms are omitted for clarity.
The liberation of one equivalent of the corresponding
CpRH derivate was proven by GC-MS. Instead of this
ligand, a second hydrazido ligand (Ph2N-(H)N-) is bound
and pyridine saturates the coordination sphere of the tita-
nium center. Product 10b is isolated independently from the
start stoichiometry. 10a was characterized via NMR spec-
troscopy, and the corresponding signals are very similar to
10b. The characteristic NMR signals are four singlets of a
CpR ligand at 5.62, 5.78, 6.22, 6.31 (10a) compared to 5.60,
5.87, 6.10, 6.19 (10b) ppm and a broadened singlet at 8.33
(10a) compared to 8.29 (10b) ppm for the NH unit. The
modes (e.g., μ1:μ2-[CpTiCl(NNPh2)]2,98 [Ti2(μ-η2,η1-NN-
Me2)2Cl4(HNMe2)2]99). The TidN bond lengths to the
˚
hydrazido(2-) ligand (1.7567(13) A) is in the range of typical
TidN double bonds, and the almost linear TidN-N angle
(171.05(11)°) indicates an sp-hybridized N atom, as found
also in comparable compounds ([Ti(NNPh2)Cl2(HC(Me2-
Pz)3)]:99 TidN 1.718(2) A,Ti-N-N 176.03(16)°;[Ti(NNMe2)-
˚
(t-Bu-bpy)(dpma)]:100 TidN 1.708(3) A, Ti-N-N 177.3(2)°;
˚
C
exoH singlet of 10b at 5.72 ppm is in the same range as the
[Ti{MeN(CH2CH2NSiMe3)2}(NNPh2)(py)]:101 TidN 1.733(5)
corresponding signals for 5b (5.30 ppm), 5c (5.42 ppm), and
7b (5.56 ppm). The complexes 10a,b do not give an Mþ signal
in the mass spectrum (neither CI nor EI mode). Crystals
suitable for X-ray structure determination were obtained
from a saturated benzene solution after a few days at room
temperature. The piano stool titanium complex 10b crystal-
lizes in the triclinic space group P1. The molecular structure
of 9 is given in Figure 6, and selected bond distances
compared to 9 are summarized in Table 5.
102
˚
A, Ti-N-N 177.7(4)°; [Ti(NNPh2)(Me2Calix)]
TidN
˚
1.717(2) A, Ti-N-N 177.3(2)°; [Ti[NN(H)Ph](t-Bu-bpy)-
(dpma)]:103 TidN 1.712(4) A; [Cp*Ti(NXylN)(NNPh2)]:104
˚
˚
TidN 1.736(2) A, Ti-N-N 168.2(2)°). A structural analogue
to 9 is found in the case of a zirconocene derivative in the form of
(98) Hughes, D. L.; Latham, I. A.; Leigh, G. J. J. Chem. Soc., Dalton
Trans. 1986, 393–398.
(99) Parsons, T. B.; Hazari, N.; Cowley, A. R.; Green, J. C.; Mount-
ford, P. Inorg. Chem. 2005, 44, 8442–8458.
(100) Li, Y.; Shi, Y.; Odom, A. L. J. Am. Chem. Soc. 2004, 126, 1794–
1803.
(106) Wilkinson, P. G.; Hounk, N. B. J. Chem. Phys. 1956, 24, 528–
534.
(101) Selby, J. D.; Manley, C. D.; Feliz, M.; Schwarz, A. D.; Clot, E.;
Mountford, P. Chem. Commun. 2007, 4937–4939.
(102) Clulow, A. J.; Selby, J. D.; Cushion, M. G.; Schwarz, A. D.;
Mountford, P. Inorg. Chem. 2008, 47, 12049–12062.
(103) Patel, S.; Li, Y.; Odom, A. L. Inorg. Chem. 2007, 46, 6373–6381.
(104) Weitershaus, K.; Wadepohl, H.; Gade, L. H. Organometallics
2009, 28, 3381–3389.
(107) Allen, F. H.; Kennrad, O.; Watson, D. G.; Brammer, L.; Orpen,
A. G.; Taylor, R. J. Chem. Soc., Perkin Trans. 2 1987, S1–S19.
(108) Pestana, D. C.; Power, P. P. Inorg. Chem. 1991, 30, 528–535.
(109) Sutton, L. E. Tables of Interatomic Distances and Configura-
tions in Molecules and Ions; Chemical Socienty: London, 1958; Vol. 11.
(110) Hoekstra, A.; Vos, A.; Braun, P. B.; Hornstra, J. Acta Cryst.,
Sect. B 1975, B31, 1708–1715.
(105) Walsh, P. J.; Carney, M. J.; Bergman, R. G. J. Am. Chem. Soc.
(111) Theilmann, O.; Saak, W.; Haase, D.; Beckhaus, R. Organome-
1991, 113, 6343–6345.
tallics 2009, 28, 2799–2807.

1814 Organometallics, Vol. 29, No. 7, 2010
Janssen et al.
titanium hydrazido(1-) complexes are unknown up to now.
The Ti-N-N angles of the (NNPh2)2- ligand are found
nearly linear (av 170°) in 9 and 10b compared to 131.53(14)°
for the (N(H)NPh2)- ligand in 10b. The N-Cphenyl bond
˚
lengths (1.40-1.44 A) are in the expected range.
The liberation of one Cp ligand during attempts of the
preparation of [Cp*2TidNNPh2(py)] is observed by Mount-
ford et al., leading to [Cp*Ti(dNNPh2)(NHNPh2)(py)],101
comparable to 10. However, the X-ray structural characteri-
zation of these Cp* derivatives failed. The mixed hydrazido-
(2-)/(1-) adduct 10 itself is comparable to Bergman’s
amide/imide complex CpTi(NAr)(NHAr)(py), which is used
as a model for the active species in the Cp2TiMe2-catalyzed
hydroamination of alkynes and allenes.81
Conclusion
Bis(pentafulvene)titanium complexes are thermally stable,
storable, and efficient alternative substrates in applications
of titanocene(IV) derivatives. In such a way, the bis(penta-
fulvene)titanium complexes have been found to be compe-
tent catalysts for intramolecular hydroamination reactions
of geminally disubstituted amino alkenes. Among the cata-
lysts investigated, best activities are found for the benzoful-
vene derivative 2.
Generally, the bis(pentafulvene)titanium complexes are
valuable reagents for the preparation of Ti-N-containing
products under comparably mild conditions. In stoichio-
metric reactions of 1 with aniline derivates and keto imines
CpR2Ti(NHAr)2 and CpR2Ti(NdCPh2)2 complexes become
available in high yields. The expected formation of imido
derivatives CpR2TidNR in reactions of primary aryl amines
with 1 is not observed. Employing the catalytically relevant
amine H2NCH2C(Ph)2CH2CHdCH2 (3a) in reaction with 1,
a selective formation of a structurally characterized titanium
monoamide (6) occurs. In reactions of diphenylhydrazine
and 1, hydrazido complexes are formed. Further detailed
mechanistic investigations are in progress.
Figure 6. ORTEP plot of the solid-state molecular structure of
˚
10b (50% probability ellipsoids). Selected bond lengths (A) and
angles (deg): Ti1-Ct1 2.076, Ti1-N3 1.7338(17), Ti1-N1
1.9575(18), Ti1-N5 2.2053(17), N1-N2 1.410(2), N2-C7
1.402(3), N2-C1 1.420(3), N3-N4 1.370(2), N4-C13 1.414(3),
N4-C19 1.422(3), Ti1-C30 2.386(2), Ti1-C31 2.382(2), Ti1-
C32 2.423(2), Ti1-C33 2.412(2), Ti1-C34 2.375(2), C30-C31
1.421(3), C30-C34 1.410(3), C30-C35 1.523(3), C31-C32
1.410(3), C32-C33 1.402(3), C33-C34 1.420(3), N3-Ti1-N1
101.55(8), N3-Ti1-N5 96.71(7), N1-Ti1-N5 98.83(7), N2-N1-
Ti1 131.53(14), C7-N2-N1 117.79(16), N1-N2-C1116.78(17),
N4-N3-Ti1 170.20(14), N3-N4-C13 116.54(17), N3-N4-
C19 118.59(17), Ct1-Ti1-N1 115.8, Ct1-Ti1-N3 122.8,
Ct1-Ti1-N5 116.9; Ct1 = centroid of C30-C34. Hydrogen
atoms are omitted for clarity.
˚
Table 5. Selected Bond Lengths [A] and Angles [deg] of 9 and 10b
9
10b
Bond Lengths
Ti-N (NNPh2)2-
Ti-N (N(H)NPh2)-
Ti-N (pyridine)
1.757(1)
1.7338(17)
1.9575(18)
2.2053(17)
1.370(2)
1.410(2)
1.414(3)
1.422(3)
1.402(3)
1.420(3)
Experimental Section
2.243(1)
1.353(2)
N-N (NNPh2)2-
N-N (N(H)NPh2)-
N-C (NNPh2)2-
General Considerations. All reactions were carried out under
an inert atmosphere of argon or nitrogen with rigorous exclu-
sion of oxygen and moisture using standard glovebox and
Schlenk techniques. Solvents were dried according to standard
procedures. Solvents were distilled over Na/K alloy and benzo-
phenone under a nitrogen atmosphere. 1H and 13C NMR
spectra were recorded on a Bruker AVANCE III 500 spectro-
meter (1H 500.1 MHz; 13C 125.8 MHz) or a Bruker AVANCE
300 spectrometer (1H 300.1 MHz). The NMR chemical shifts
were referenced to residual protons of the solvent (benzene-d6 or
CDCl3) or the internal standard TMS. Electron impact (EI)
mass spectra were taken on a Finnigan-MAT 95 spectrometer.
IR spectra were recorded on a Bio-Rad FTS-7 spectrometer
using KBr pellets or on a Bruker Tensor 27 spectrometer using
an attenuated total reflection (ATR) method. Elemental ana-
lyses were carried out on a EuroEA 3000 elemental analyzer.
Melting points were determined using a Mel-Temp by Labora-
tory Devices, Cambridge. The bis(fulvene)titanium complexes 1
and 2 were prepared according to literature procedures.3 The
1,1-diphenylhydrazine was generated from the hydrochloride by
the literature method.114 All hydroamination reactions were
performed under an inert atmosphere of nitrogen in oven-dried
1.401(2)
1.438(2)
N-C (N(H)NPh2)1-
Bond Angles
171.1(1)
Ti-N-N (NNPh2)2-
170.20(14)
131.53(14)
Ti-N-N (N(H)NPh2)-
In the molecular structure of 10b the (NNPh2)2- and the
(N(H)NPh2)- ligand can easily be distinguished by the TidN
˚
double bond length of 1.7338(17) A as a typical double bond
˚
(comparable to 1.757(1) A in 9, vide supra) in contrast to the
˚
Ti-N single bond length of 1.9575(18) A for a slightly
shortened single bond (comparable to 1.96 A in 7a). Both
˚
hydrazido ligands are bonded in a end-on coordina-
tion mode, in contrast to side-on hydrazido(2-)98-100 and
hydrazido(1-)95-97,100,112,113 ligands. To the best of our
knowledge, structurally characterized end-on coordinated
(112) Hemmer, R.; Thewalt, U.; Hughes, D. L.; Leigh, G. J.; Walker,
D. G. J. Organomet. Chem. 1987, 323, C29–C32.
(113) Hughes, D. L.; Jimenez-Tenorio, M.; Leigh, G. J.; Walker,
(114) Blake, A. J.; McInnes, J. M.; Mountford, P.; Nikonov, G. I.;
Swallow, D.; Watkin, D. J. J. Chem. Soc., Dalton Trans. 1999, 379–391.
D. G. J. Chem. Soc., Dalton Trans. 1989, 2389–2395.

Article
Organometallics, Vol. 29, No. 7, 2010 1815
Schlenk tubes (Duran glassware, 100 mL, i 30 mm) equipped
with Teflon stopcocks and magnetic stirring bars (15 ꢀ 4.5 mm).
For flash chromatography, silica gel 60 from Fluka (230-
400 mesh, particle size 0.040-0.063 mm) was used. PE: light
petroleum ether, bp 40-60 °C. MTBE: tert-butyl methyl ether.
Hydroamination of Nonvolatile Aminoalkenes. General Pro-
cedure A. An oven-dried Schlenk tube equipped with a Teflon
stopcock and a magnetic stirring bar was transferred into a
nitrogen-filledglovebox andchargedwiththe catalyst (0.12 mmol,
5 mol %), toluene (1.0 mL), the aminoalkene (2.40 mmol), and
toluene (1.0 mL). Then the tube was sealed and the resulting
mixture was heated to 105 °C for 24 h. After the mixture had
been cooled to room temperature, the solution was diluted with
CH2Cl2 (30 mL) and washed with saturated aqueous NH4Cl
solution. The aqueous layer was extracted with CH2Cl2 (3 ꢀ
50 mL), and the combined organic layers were dried with
MgSO4. After concentration under vacuum in the presence of
Celite, the product was isolated by flash chromatography.
Hydroamination of Volatile Aminoalkenes and Subsequent
Formation of Benzoylamides. General Procedure B. An oven-
dried Schlenk tube equipped with a Teflon stopcock and a
magnetic stirring bar was transferred into a nitrogen-filled
glovebox and charged with the catalyst (0.12 mmol, 5 mol %),
toluene (1.0 mL), the aminoalkene (2.40 mmol), and toluene
(1.0 mL). Then the tube was sealed, and the resulting mixture
was heated to 105 °C for 24 h. After the mixture had been cooled
to room temperature, CH2Cl2 (10 mL) and NEt3 (1.0 mL,
7.2 mmol) were added. Then benzoyl chloride (0.3 mL, 2.64
mmol) was added dropwise at 25 °C, and the resulting mixture
was stirred for 12 h. Then the solution was diluted with CH2Cl2
(30 mL) and washed with a saturated aqueous NH4Cl solution.
The aqueous layer was extracted with CH2Cl2 (3 ꢀ 50 mL), and
the combined organic layers were dried with MgSO4. After
concentration under vacuum in the presence of Celite, the
product was isolated by flash chromatography.
2-Methyl-4,4-diphenylpyrrolidine (4a). General procedure A
was used to synthesize 4a from 1-amino-2,2-diphenyl-4-pentene
(3a, 570 mg, 2.40 mmol). After chromatography (SiO2, MTBE/7
N NH3 in MeOH, 95:5, Rf = 0.35), 4a (502 mg, 2.12 mmol, 88%,
catalyst: 2) was obtained as a colorless oil. IR (neat): 1/λ 2960
(w), 2869 (w), 1599 (w), 1494 (m), 1447 (m), 1374 (w), 1099 (w),
1034 (w), 774 (m), 756 (m), 698 (s) cm-1. 1H NMR (CDCl3, 500
MHz): δ 1.20 (d, J = 6.7 Hz, 3 H, CH3), 2.03 (dd, J = 12.5, 8.9
Hz, 1 H, CH3-CH-CH2), 2.10 (br s, 1 H, NH), 2.74 (dd, J = 12.5,
6.4 Hz, 1 H, CH3-CH-CH2), 3.32-3.41 (m, 1 H, CH3-CH), 3.47
(d, J = 11.0 Hz, 1 H, NH-CH2), 3.67 (d, J = 11.6 Hz, 1 H, NH-
CH2), 7.14-7.18 (m, 2 H, aryl-H), 7.20-7.31 (m, 8 H, aryl-H)
ppm. 13C NMR (CDCl3, 126 MHz, DEPT): δ 22.3 (CH3), 47.0
(CH2), 53.0 (CH), 57.2 (C), 57.9 (CH2), 125.9 (CH), 125.9 (CH),
126.9 (CH), 127.0 (CH), 128.2 (CH), 128.3 (CH), 147.0 (C),
147.8 (C) ppm. MS (EI, 70 eV): m/z (%) 237 (12) [M]þ, 178 (5),
165 (6), 115 (5), 91 (4), 57 (100), 56 (6). HRMS: calcd (C17H19N)
237.1517; found 237.1520.
264 (14), 250 (12), 187 (14), 174 (51), 173 (53), 115 (12), 96 (37),
91 (92), 65 (13), 57 (100). HRMS: calcd (C19H23N) 265.1830;
found 265.1827.
(3-Methyl-2-azaspiro[4.5]decan-2-yl)(phenyl)methanone (4c).
General procedure B was used to synthesize 4c from (1-allylcy-
clohexyl)methanamine (3c, 368 mg, 2.40 mmol). After chromato-
graphy (SiO2, PE/EtOAc, 80:20, Rf = 0.57), 4c (433 mg, 1.68 mmol,
70%, catalyst: 2) was obtained as a colorless oil. IR (neat): 1/λ 2992
(m), 2853 (m), 1626 (vs), 1577 (m), 1447 (s), 1403 (vs), 1354 (w),
1304 (w), 1221 (w), 1179 (w), 1142 (w), 1106 (w), 792 (m), 716 (s),
1
698 (s), 661 (s) cm-1. H NMR (CDCl3, 500 MHz, 50 °C): δ
1.22-1.49 (m, 14 H), 2.12 (dd, J = 12.6, 7.5 Hz, 1 H, CH3-CH-
CH2), 3.16 (d, J = 11.0 Hz, 1 H, NH-CH2), 3.29 (br s, 1 H, NH-
CH2), 4.30 (br s, 1 H, CH3-CH), 7.33-7.41 (m, 3 H), 7.43-7.55 (m,
2 H) ppm. 13C NMR (CDCl3, 126 MHz, DEPT, 50 °C): δ 20.3
(CH3), 22.6 (CH2), 23.7 (CH2), 26.1 (CH2), 33.7 (CH2), 36.3 (CH2),
42.2 (C), 44.8 (CH2), 52.0 (CH), 60.2 (CH2), 127.2 (CH), 128.1
(CH), 129.6 (CH), 137.5 (C), 170.1 (C) ppm. MS (EI, 70 eV): m/z
(%) 257 (10) [M]þ, 242 (6), 161 (5), 160 (12), 106 (6), 105 (100), 77
(25), 56 (7), 41 (4). HRMS: calcd (C17H24NO) 258.1858; found
258.1864.
Phenyl(2,4,4-trimethylpyrrolidin-1-yl)methanone (4d). Gener-
al procedure B was used to synthesize 4d from 1-amino-2,2-
dimethyl-4-pentene (3d, 272 mg, 2.40 mmol). After chromato-
graphy(SiO2, PE/EtOAc, 80:20, Rf =0.27) 4d (91mg, 0.42mmol,
18%, catalyst: 2) was obtained as a colorless oil. IR (neat): 1/λ
2957 (m), 2868 (m), 1716 (w), 1626 (vs), 1577 (m), 1447 (m), 1403
(vs), 1372 (m), 1352 (m), 1290 (m), 1213 (m), 1136 (m), 1074 (w),
851 (w), 792 (m), 716 (s), 698 (s), 661 (m) cm-1. 1H NMR (CDCl3,
500 MHz): δ 0.91 (s, 3 H, CH3), 1.05 (s, 3 H, CH3), 1.37-1.45 (m,
4 H), 1.95 (dd, J = 12.8, 7.3 Hz, 1 H, CH3-CH-CH2), 3.10 (d, J =
10.4 Hz, 1 H, NH-CH2), 3.29 (d, J = 10.4 Hz, 1 H, NH-CH2),
4.31-4.40 (m, 1 H, CH3-CH), 7.36-7.55 (m, 5 H, aryl-H) ppm.
13C NMR (CDCl3, 126 MHz, DEPT): δ 20.2 (CH3), 25.4 (CH3),
25.7 (CH3), 38.2 (C), 47.5 (CH2), 52.9 (CH), 62.6 (CH2), 127.5
(CH), 128.1 (CH), 129.9 (CH), 137.1 (C), 170.1 (C) ppm. MS (EI,
70eV): m/z (%) 217 (14) [M]þ, 174 (26), 105 (100), 77 (82), 56(64),
55 (27), 51 (51), 50 (11), 42 (14), 41 (47). HRMS: calcd
(C14H19NO) 217.1467; found 217.1464.
X-ray Diffraction. Single-crystal experiments were performed
on a Stoe IPDS or Bruker ApexII diffractometer with graphite-
˚
monochromated Mo KR radiation (λ = 0.71073 A). The struc-
tures were solved by direct phase determination and refined by
full-matrix least-squares techniques against F2 with the SHELXL-
97 program system.115 X-ray data of compounds 5a, 6, 7a, 9, and
10b are given in Table 6 (for 5b, 5c, 5d, and 7b see ref 83).
CpAd2Ti(NHp-tolyl)2, 5a. 1a (200 mg, 0.45 mmol) and 96 mg
(0.9 mmol) of p-methylaniline were placed in a Schlenk tube, and
20 mL of n-hexane was added. The color of the reaction mixture
changed instantly from green to red. Storing the solution for a
few days at room temperature and filtration led to a fine
crystalline product. X-ray-quality crystals were obtained from
a saturated n-hexane solution of X at room temperature. The
solid product can be handled without inert atmosphere for short
periods. Yield: 112 mg (38%). Mp: 162 °C. IR (KBr): 1/λ 3364
(s), 3087 (w), 2999 (s), 2896 (vs), 2848 (s), 1601 (s), 1565 (w), 1496
(vs), 1447 (s), 1351 (w), 1294 (w), 1260 (vs), 1170 (s), 1098 (s),
1060 (w), 972 (w), 951 (w), 884 (w), 854 (s), 897 (vs), 764 (s), 649
(w), 571 (w), 529 (w), 511 (s) cm-1. 1H NMR (C6D6, 500 MHz):
δ 1.37-2.77 (m, 28 H, adamantyl), 2.18 (s, 6 H, CH3), 5.64 (s,
4 H, C5H4), 6.06 (s, 4 H, C5H4), 6.85 (d, J = 7.8 Hz, 4 H,
C6H4CH3), 6.97 (d, J = 7.9 Hz, 4 H, C6H4CH3), 7.39 (s, 2 H,
NH) ppm. 13C NMR (C6D6, 125 MHz): δ 20.8 (CH3), 28.0, 28.1,
32.2, 32.7, 38.1, 39.0, 44.5 (adamantyl), 110.7, 112.2, 118.5
(C5H4), 127.1, 128.3, 129.0, 129.4 (tolyl) ppm. MS (EI, 70 eV):
m/z (%) 106.1 (59) [NH-p-tolyl]þ, 200.1 (100) [CpHAd]þ, 335.0
(6) [CpAdTi(NH-p-tolyl)]þ.
4,4-Dibenzyl-2-methylpyrrolidine (4b). General procedure A
was used to synthesize 4b from 1-amino-2,2-dibenzyl-4-pentene
(3b, 637 mg, 2.40 mmol). After chromatography (SiO2, MTBE/7
N NH3 in MeOH, 90:10, Rf = 0.32), 4b (593 mg, 2.23 mmol,
93%, catalyst: 2) was obtained as a colorless oil. IR (neat): 1/λ
3026 (w), 2955 (w), 2921 (w), 2885 (w), 1602 (w), 1494 (m), 1453
(m), 1373 (w), 1083 (w), 1030 (w), 750 (s), 738 (s), 700 (vs) cm-1
.
1H NMR (CDCl3, 500 MHz): δ 0.97 (d, J = 6.7 Hz, 3 H, CH3),
1.30 (dd, J = 12.8, 9.2 Hz, 1 H, CH3-CH-CH2), 1.44 (br s, 1 H,
NH), 1.90 (dd, J = 12.8, 7.3 Hz, 1 H, CH3-CH-CH2), 2.73 (d,
J = 6.1 Hz, 4 H, CH2-aryl), 2.82 (d, J = 11.6 Hz, 1 H, NH-CH2),
2.94 (d, J = 11.6 Hz, 1 H, NH-CH2), 2.95-3.02 (m, 1 H, CH3-
CH), 7.14-7.25 (m, 6 H, aryl-H), 7.26-7.31 (m, 4 H, aryl-H)
ppm. 13C NMR (CDCl3, 126 MHz, DEPT): δ 21.4 (CH3), 43.9
(CH2), 45.0 (CH2), 45.3 (CH2), 48.7 (C), 54.1 (CH), 56.2 (CH2),
126.1 (CH), 126.1 (CH), 128.0 (CH), 130.4 (CH), 130.5 (CH),
139.0 (C), 139.1 (C) ppm. MS (EI, 70 eV): m/z (%) 265 (6) [M]þ,
(115) Sheldrick, G. M. SHELXL-97. A Program for Refining Crystal
€
Structures; University of Gottingen: Germany, 1997.

1816 Organometallics, Vol. 29, No. 7, 2010
Table 6. Crystal Structure Data for Compounds 5a, 6, 7a, 9, and 10b
Janssen et al.
5a
6
7a
9
10b
empirical formula
fw
C44H54N2Ti
658.79
C47H55NTi
681.82
C59H65N2Ti
850.03
C47H53N3Ti
707.82
C58H58N5Ti
872.99
color, habit
cryst dimens, mm
cryst syst
dark red prisms
0.45 ꢀ 0.31 ꢀ 0.17
monoclinic
P21/n
11.7970(6)
13.6327(5)
22.8239(12)
90
97.930(6)
90
3635.6(3)
4
1.204
0.268
153(2)
2.34 to 26.13
38 728
7181 [R(int) =
0.0548]
4561
orange red crystals
0.35 ꢀ 0.21 ꢀ 0.05
triclinic
dark red needles
1.10 ꢀ 0.34 ꢀ 0.13
monoclinic
P21/c
12.2434(8)
34.6448(14)
11.6890(6)
90
105.166(7)
90
4785.4(4)
4
1.180
0.219
153(2)
2.09 to 26.09
40 335
8895 [R(int) =
0.0629]
5282
red crystals
0.78 ꢀ 0.56 ꢀ 0.37
monoclinic
P21/n
12.2755(4)
13.1717(5)
23.3612(8)
90
99.800(2)
90°
3722.1(2)
4
1.263
0.268
153(2)
3.07 to 29.21
40 459
9952 [R(int) =
0.0320]
7599
red brown prisms
0.27 ꢀ 0.21 ꢀ 0.14
triclinic
space group
˚
P1
P1
a, A
10.3527(5)
12.7086(6)
15.6582(7)
73.898(3)
82.947(3)
66.625(3)
1816.67(15)
2
1.246
0.270
153(2)
3.32 to 30.11
40 975
12.8053(4)
12.8506(4)
15.4208(5)
93.880(2)
104.058(2)
102.959(2)
2378.78(13)
2
1.219
0.224
153(2)
2.59 to 28.00
35 642
˚
b, A
˚
c, A
R, deg
β, deg
γ, deg
3
˚
V, A
Z
Dcalc, g cm-3
μ, mm-1
T, K
θ range, deg
no. of reflns colld
no. of indep reflns
10 585 [R(int) =
0.0411]
7340
11 313 [R(int) =
0.0436]
7031
no. of reflns
with I > 2σ(I)
abs corr
numerical
numerical
none
numerical
none
max., min. transmn
final R indices
(I > 2σ(I))
0.9558 and 0.8888
R1 = 0.0305,
wR2 = 0.0630
R1 = 0.0584,
wR2 = 0.0670
0.9864 and 0.9116
R1 = 0.0544,
wR2 = 0.1306
R1 = 0.0900,
wR2 = 0.1499
0.9721 and 0.7948
R1 = 0.0420,
wR2 = 0.1038
R1 = 0.0748,
wR2 = 0.1128
0.9079 and 0.8191
R1 = 0.0449,
wR2 = 0.1119
R1 = 0.0670,
wR2 = 0.1273
0.9694 and 0.9425
R1 = 0.0508,
wR2 = 0.1096
R1 = 0.1020,
wR2 = 0.1289
R indices (all data)
CpTol2Ti(NHp-tolyl)2, 5b. 5b was prepared in the same man-
ner with 200 mg (0.35 mmol) of 1b and 76 mg (0.7 mmol) of p-
methylaniline. Yield: 175 mg (64%). Mp: 155 °C. IR (KBr): 1/λ
3365 (w), 3001 (s), 2914 (s), 2853 (s), 1602 (s), 1498 (vs), 1445 (w),
1374 (w), 1292 (w), 1257 (vs), 1172 (w), 1105 (s), 1019 (s), 944
(w), 919 (w), 891 (w), 853 (w), 804 (vs), 759 (s), 574 (s), 535 (w),
508 (s), 483 (s) cm-1. 1H NMR (C6D6, 300 MHz): δ 2.08 (s, 12 H,
CH3), 2.22 (s, 6 H, CH3-aniline), 5.13 (s, 4 H, C5H4), 5.30 (s, 2 H,
C5H4-CH), 5.88 (s, 4 H, C5H4), 6.89-6.99 (m, 16 H, C6H4CH3),
7.09 (d, J = 8.0 Hz, 8 H, aniline), 7.84 (s, 2 H, NH) ppm. MS (EI,
70 eV): m/z (%) 106 [p-tolyl-NH]þ, 258 [p-tolyl2Fv]þ, 260
[CpRH]þ, 516.3 [M - CpR - 3H]þ.
naphthyl), 7.27 (t, J = 7.7 Hz, 2 H, naphthyl), 7.33 (t, J =
7.5 Hz, 2 H, naphthyl), 7.42 (t, J = 7.6 Hz, 2 H, naphthyl), 7.55
(d, J = 7.2 Hz, 2 H, naphthyl), 7.72 (d, J = 8.1 Hz, 2 H,
naphthyl), 7.89 (d, J = 8.4 Hz, 2 H, naphthyl), 8.30 (s, 2 H, NH)
ppm. 13C NMR (C6D6, 125 MHz): δ 28.0, 28.1, 32.2, 32.5, 38.0,
38.6, 44.0 (adamantly), 111.0, 112.2, 116.0, 118.9, 121.6, 124.2,
124.7, 125.3, 129.2, 131.1, 135.0, 154.3 (C-N) ppm. MS (EI,
70 eV): m/z (%) 143 (100) [naphthyl-NH2]þ, 200 (43) [CpRH]þ,
267 (22) [CpCHTiNH-naphthyl]þ, 446 (2) [CpR2Ti]þ, 465 (10)
[CpRCpCHTiNH-naphthyl]þ, 587 (11) [CpR2TiNH-naphthyl]þ.
Anal. Calcd for C50H54N2Ti: C 80.53; H 7.45, N 3.83. Found: C
80.59, H 7.76, N 3.75.
CpTol2Ti(NH-naphthyl)2, 5c. 5c was prepared in the same
manner with 200 mg (0.35 mmol) of 1b and 102 mg (0.7 mmol)
of 1-naphthylamine. Yield: 132 mg (44%). Mp: 162 °C. IR
(KBr): 1/λ 3042 (w), 3015 (w), 2914 (w), 1563 (s), 1506 (s), 1438
(s), 1391 (vs), 1284 (s), 1221 (s), 1089 (s), 1018 (s), 918 (w), 882 (s),
815 (s), 784 (s), 764 (vs), 721 (s), 643 (w), 617 (s), 571 (s), 542 (w),
CpAd2TiNHCH2CPh2CH2CHdCH2, 6. 1a (178 mg, 0.4
mmol) was placed in a Schlenk tube, and 5 mL of benzene was
added. Then 95 mg (0.4 mmol) of 3a was dissolved in 10 mL of n-
hexane and added to the reaction solution. The color of the
reaction mixture changed instantly from green to red. Crystals
of X-ray-quality were obtained from the solution after a few
days at 6 °C. Yield: 42 mg (15.5%). Mp: 108 °C. IR (KBr): 1/λ
3350 (s), 3055 (w), 2900 (vs), 2846 (s), 2360 (w), 2342 (w), 1634
(vw), 1597 (vw), 1494 (s), 1447 (s), 1384 (w), 1260 (s), 1098 (vs),
914 (s), 870 (s), 793 (s), 756 (s), 723 (w), 699 (s), 665 (w), 564 (w)
1
507 (s), 482 (s) cm-1. H NMR (C6D6, 500 MHz,): δ 2.03 (s,
12 H, CH3), 5.42 (s, 2 H, C5H4-CH), 5.61 (t, 3J = 2.7 Hz, 4 H,
C5H4), 6.06 (t, 3J = 2.6 Hz, 4 H, C5H4), 6.82 (d, 3J = 7.9 Hz,
8 H, tolyl), 7.03 (d, J = 8.0 Hz, 8 H, tolyl), 7.15 (t, 3J = 7.8 Hz,
2 H, naphthyl), 7.21 (d, 3J = 8 Hz, 2 H, naphthyl), 7.35 (t, 3J =
7.6 Hz, 4 H, naphthyl), 7.44, (td, J = 7.0 Hz, 2 H, naphthyl), 7.73
(d, J = 7.5 Hz, 2 H, naphthyl), 8.08 (d, J = 8.5 Hz, 2 H,
naphthyl), 8.72 (s, 2 H, NH) ppm. 13C NMR (C6D6, 125 MHz,):
δ 20.9 (CH3), 31.9 (CH3), 52.2 (C5H4-CHR2), 110.6 (C5H4),
115.0 (C5H4), 115.8 (C5H4), 118.9 (C5H4), 121.9, 124.3, 124.4,
125.3, 127.8, 128.0, 128.2, 128.3, 129.1, 129.2, 129.4, 131.1,
135.0, 136.1, 142.0, 153.9 (NH-C) ppm. MS (EI, 70 eV): m/z
(%) 143 [Naph - NH2]þ, 258 [Fv]þ, 260 [Fv þ2H)]þ.
cm-1 1H NMR (C6D6, 500 MHz): δ 1.42-2.90 (m, 29 H,
.
adamantyl), 2.77 (m, 2 H, -CH2-CHd), 4.0 (d, J = 6.4 Hz, 2
H, -NH-CH2-), 4.13, 5.24, 5.29, 5.99 (s, 4 H, C5H4-Fv), 4.9, 5.0
(m, 2 H, dCH2), 5.05, 5.08, 5.72, 5.86 (s, 4 H, C5H4--Cp), 5.5
(m, 1 H, -CHd), 6.15 (s, 1 H, NH), 7.03-7.14 (m, 10 H, C6H5)
ppm. 13C NMR (C6D6, 125 MHz): δ 28.3-64.3 (adamantyl/
adamantylidene), 42.3 (-CH2-CHd), 64.3 (NH-CH2-), 100.8,
107.7, 108.1, 113.2 (C5H4), 107.7, 111.5, 113.2 (C5H4-Fv),109.8
(-CHd), 117.3 (dCH2), 125.1-128.7 (Ph) ppm. MS (EI, 70 eV):
m/z (%) 200 (100) [CpRH]þ, 445 (33) [CpRFvTi]þ. MS (CI,
isobutane): m/z (%) 200 (42) [CpRH]þ, 236 (100) [amine-H]þ,
443 (14) [CpR2Ti]þ, 681 (8) [M]þ. Anal. Calcd for C53H69NTi: C
81.33; H 9.06, N 1.82. Found: C 81.64, H 8.95, N 1.62.
CpAd2Ti(NH-naphthyl)2, 5d. 5d was prepared in the same
manner with 178 mg (0.4 mmol) of 1a and 115 mg (0.8 mmol)
of 1-naphthylamine. Yield: 170 mg (61%). Mp: 159 °C. IR
(KBr): 1/λ 2997 (s), 2847 (s), 1565 (s), 1504 (m), 1447 (m), 1397
(s), 1286 (s), 1225 (s), 1113 (m), 1090 (m), 1048 (m), 1019 (m), 885
(m), 818 (s), 783 (m), 768 (s), 723 (m), 572 (m), 515 (m), 391 (m)
CpAd2Ti(NdCPh2)2, 7a. 1a (200 mg 0.45 mmol) was placed in
a Schlenk tube, and 40 mL of n-hexane was added. Then 163 mg
(0.9 mmol) of benzophenone imine was added, and the color of
the reaction mixture changed instantly from green to red.
Storing the solution for a few days at room temperature and
cm-1 1H NMR (C6D6, 500 MHz): δ 1.58-1.82 (m, 24 H,
.
adamantyl), 1.99 (s, 4 H, adamantyl), 2.96 (s, 2 H, adamantyl),
5.70 (s, 4 H, C5H4), 6.10 (s, 4 H, C5H4), 7.24 (d, J = 7.8 Hz, 2 H,

Article
Organometallics, Vol. 29, No. 7, 2010 1817
filtration led to a fine crystalline product. X-ray-quality crystals
were obtained from a saturated n-hexane solution at room
temperature. In the solid state, 7a can be handled without inert
atmosphere for short periods. Yield: 238 mg (74%). Mp: 179 °C
(dec.). IR (KBr): 1/λ 3054 (w), 2897 (s), 2847 (m), 1616 (s), 1442
(m), 1232 (m), 1025 (m), 887 (m), 777 (s), 694 (s), 621 (m), 475
Crystals of X-ray quality were not obtained. Yield: 46 mg
(16%). Mp: 108 °C. H NMR (C6D6, 300 MHz): δ 1.44-2.34
1
(m, 14 H, adamantyl), 3.15 (s, 1 H, adamantyl), 5.62 (s, 1 H,
C5H4), 5.78 (s, 1 H, C5H4), 6.22 (t, J = 6.9 Hz, 2H, meta-
C5H5N), 6.31 (s, 1 H, C5H4), 6.32 (s, 1 H, C5H4), 6.66 (t, J =
7.6 Hz, 1 H, para-C5H5N), 6.80 (t, J = 7.2 Hz, 2 H, para-C6H5),
6.86 (t, J = 7.3 and 7.5 Hz, 2 H, para-C6H5), 7.08 (t, J = 7.7 Hz,
4 H, meta-C6H5), 7.18 (t, J = 7.7 Hz, 4 H, meta-C6H5), 7.26 (d,
J = 8.0 Hz, 4 H, ortho-C6H5), 7.65 (d, J = 7.7 Hz, 4 H, ortho-
C6H5), 8.20 (d, J = 4.8 Hz, 2 H, ortho-C5H5N), 8.33 (s, 1 H,NH)
ppm.
(m), 409 (m), 343 (w) cm-1 1H NMR (C6D6, 500 MHz): δ
.
1.36-1.99 (m, 28 H, adamantyl), 3.26 (s, 2 H, adamantyl), 5.47
(t, J = 2.6 Hz, 4 H, C5H4), 5.89 (t, J = 2.6 Hz, 4 H, C5H4), 7.19
(t, J = 7.2 Hz, 4 H, para-C6H5), 7.27 (t, J = 7.5 Hz, 8 H, ortho-
C6H5), 7.56 (d, J = 7.2 Hz, 8 H, meta-C6H5) ppm. 13C NMR
(C6D6, 125 MHz): δ 23.0, 28.1, 28.2, 32.1, 32.3, 38.1, 38.4, 42.7
(adamantly), 101.8, 114.9 (C5H4), 128.3, 128.4, 128.5, 128.5,
131.3, 141.5 (C6, 165.9 (-NdC) ppm. MS (EI, 70 eV): m/z (%)
180 (29) [Ph2CN]þ, 198 (10) [AdFv]þ, 444 (11) [AdFv2Ti - 2H],
446 (8) [CpR2Ti]þ, 625 (100) [CpR2TiNdCPh2]þ. Anal. Calcd
for C66H58N2Ti: C 81.86, H 7.24, N 3.47. Found: C 81.60, H
7.59, N 3.46.
CpTolTidN-NPh2(-NH-NPh2)py, 10b. 1b (565 mg , 1 mmol)
was placed in a Schlenk tube, and 10 mL of benzene was added.
Then 370 mg (2 mmol) of N,N-diphenylhydrazine was dissolved
in 20 mL of n-hexane, and this was added to the reaction
solution. The color of the reaction mixture changed instantly
from green to red. Then 0.2 mL (2.4 mmol) of pyridine was
added and the reaction mixture stirred for 70 h. After filtration
from the solvent the light yellow-brown product was dried in
vacuo. X-ray-quality crystals were obtained from a saturated
benzene solution. Yield: 449 mg (49%). Mp: 111 °C. (KBr): 1/λ
3255 (w), 3015 (w), 2913 (w), 1582 (vs), 1486 (vs), 1441 (s), 1364
(w), 1273 (s), 1260 (w), 1152 (w), 1068 (w), 1020 (w), 937 (w), 804
(vs), 743 (vs), 694 (vs), 574 (w), 503 (s) cm-1. 1H NMR (C6D6,
500 MHz): δ 2.03 (s, 3 H, CH3), 2.18 (s, 3 H, CH3), 5.60 (s, 1 H,
C5H4), 5.87 (s, 1 H, C5H4), 6.10 (s, 1 H, C5H4), 6.19 (s, 1 H,
C5H4), 5.72 (s, 1 H, C5H4-CHR2), 6.14 (t, 2 H, J = 7.2 and 6.6
Hz, meta-NC5H5), 6.61 (t, 1 H, J = 7.6 Hz, para-NC5H5), 6.77
(t, 2 H, 3J = 7.2 Hz, para-C6H5), 6.85 (m, 2 H, meta-C6H4CH3),
6.88 (t, 2 H, J = 8.2 Hz, para-C6H5), 7.00 (m, 2 H, meta-
C6H4CH3), 7.01-7.18 (m, 12 H, C6H5), 7.11 (m, 2 H, ortho-
C6H4CH3), 7.31 (m, 2 H, 3J = 7.9 Hz, ortho-C6H4CH3), 7.68 (d,
4H, 3J = 8.0 Hz, ortho-C6H6), 8,03 (d, 2 H, 3J = 4.9 Hz, ortho-
NC5H5), 8.29 (s, 1 H, NH) ppm. 13C NMR (C6D6, 125 MHz): δ
20.9 (CH3), 21.1 (CH3), 51.8 (Cp-CHR2), 106.2 (C5H4), 109.6
(C5H4), 112.4 (C5H4), 112.5 (C5H4), 119.2 (para-C6H5), 119.7
(para-C6H5), 119.8 (para-C6H5), 120.2 (para-C6H5), 122.1
(meta-C6H4CH3), 123.5 (meta-C5H5N), 128.3 (meta-C6H4CH3),
128.5, 128.9 (meta-C6H4CH3), 129.0 (ortho-C6H4CH3), 129.2
(ortho-C6H4CH3), 129.3, 129.4, 129.5, 129.8, 135.1, 135.3, 137.2
(para-C5H5N), 142.5, 144.0, 146.9, 149.7, 153.1 (ortho-C5H5N)
ppm. Anal. Calcd for C52H52N5Ti: C 78.57; H 6.59, N 8.81.
Found: C 78.14, H 6.72, N 8.74.
CpTol2Ti(NdCPh2)2, 7b. This was prepared in the same
manner with 200 mg (0.35 mmol) of 1b and 99 mg (0.7 mmol)
of benzophenone imine. Yield: 178 mg (54%). Mp: 154 °C (dec).
IR (KBr): 1/λ 3015 (m), 2918 (m), 1609 (s), 1509 (s), 1486 (m),
1441 (m), 1233 (s), 1071 (m), 1056 (m), 1022 (m), 890 (s), 838 (m),
798 (m), 780 (s), 763 (s), 697 (s), 624 (m), 574 (m), 507 (m), 479
1
(m) cm-1. H NMR (C6D6, 500 MHz): δ 2.01 (s, 12 H, CH3),
5.22 (t, J = 2.6 Hz, 4 H, C5H4), 5.56 (s, 2 H, C5H4-CH), 5.76 (t,
J = 2.6 Hz, 4 H, C5H4), 6.79 (d, J = 7.8 Hz, 8 H, C6H4CH3),
7.00 (d, J = 8.0 Hz, 8 H, C6H4CH3), 7.16-7.19 (m, 4 H, para-
C6H5), 7.20-7.24 (m, 8 H, ortho-C6H5), 7.44 (d, 3J = 7 Hz, 8 H,
meta-C6H5) ppm. 13C NMR (C6D6, 125 MHz): δ 20.9 (CH3),
50.8 (Cp-CHR2), 104.2 (C5H4), 115.6 (C5H4), 128.1, 128.3,
128.7, 129.1, 129.5, 131.4, 135.3, 142.5, 142.8, 167.3 (-NdC)
ppm. MS (EI, 70 eV): m/z (%) 180 (29) [Ph2CN]þ, 258 (26) [Fv]þ,
306 (70) [CpCHTiNdCPh2]þ, 384 (35) [CpRTiNdCPh2 - tolyl]þ,
487 (100) [CpRTiNdCPh2]þ, 565 (18) [FvR2Ti]þ, 667 (1)
[CpRTi(NdCPh2)2]þ, 745 (36) [CpR2TiNdCPh2]þ. Anal. Calcd
for C66H58N2Ti: C 84.22, H 6.31, N 3.02. Found: C 84.42, H
6.59, N 3.10.
CpAd2Ti(dN-NPh2)py, 9. 1a (178 mg, 0.4 mmol) was placed in
a Schlenk-tube and 2 mL benzene were added. 74 mg (0.4 mmol)
N,N-diphenylhydrazin were dissolved in 10 mL n-hexane and
added. The color of the reaction mixture changed instantly from
green to red. Then 0.1 mL (1.2 mmol) pyridine were given to the
reaction mixture. After storing the solution for a few days at 6 °C
crystals with X-ray-quality were obtained. Yield: 53 mg (12%).
Mp: 108 °C (dec.). Due to the high reractivity and spontanous
subsequent reactions of 9, forming 10b and further uncharac-
terized products, no further analytical data of 9 are available.
CpAdTidN-NPh2(-NH-NPh2)py, 10a. 1a (178 mg, 0.4 mmol)
was placed in a Schlenk tube, and 2 mL of benzene was added.
Then 148 mg (0.8 mmol) of N,N-diphenylhydrazine was dis-
solved in 10 mL of n-hexane, and this was added to the reaction
solution. The color of the reaction mixture changed instantly
from green to red. Then 0.1 mL (1.2 mmol) of pyridine was
added and the reaction mixture refluxed for a minute. The
product was isolated from the solution by filtration as a pale
brown-yellow solid after a few days at room temperature.
Acknowledgment. This investigation was financially
supported by the Deutsche Forschungsgemeinschaft.
Supporting Information Available: Additional crystallographic
data for structures 5-10 have been deposited with the Cambridge
Data Centre as supplementary publications nos. CCDC 75899
(5d), 75900 (5a), 759001 (7a), 759002 (7b), 759003 (9), 759004
(10b), 759005 (6), 759006 (5c), and 761178 (5b). Copies of the data
can be obtained free of charges on application to CCDC, 12 Union
Road, Cambridge CB21EZ, U.K. (fax (þ44)1223-336-033; e-mail
deposit@ccdc.cam.ac.uk), or free of charge via the Internet at
http://pubs.acs.org.