1-Methylimidazolin-2-yl functionalized cyclopentadienyl complexes of titanium and zirconium. Crystal structure of {[η5:η1-κN-C5H 4CPh2CH2-(1-Me-C3H4 N2)]ZrCl2}2(μ-Cl)2

Article abstract of DOI:10.1016/j.jorganchem.2008.04.015

The novel bidentate ligand, C₅H₄CPh₂CH₂-(1-Me-C ₃H₄N₂) (3), has been prepared and characterized as its lithium salt LiC₅H₄CPh₂CH₂-(1-Me-C ₃H₄N₂) (3-Li). Cyclopentadiene HC₅H₄CPh₂CH₂-(1-Me-C ₃H₄N₂) (3-H) has been obtained from 6,6-diphenylfulvene and 1,2-dimethylimidazoline (1). In THF-d₈ solution in the presence of 1, (1-methylimidazoline-2-yl)methyllithium (2) has been proved to undergo gradual conversion into a dilithium derivative of N¹-methyl-N²-[(1E,2E)-1-methyl-2-(1-methylimidazol idine-2-idene)ethylidene]ethane-1,2-diamine (2a). In a solution, cyclopentadiene 3-H has been shown to undergo isomerization into 3-{N-[2-(N-methylamino)ethyl]amino}-1,1-diphenyl-1,2-dihydropentalene (4) and, further, into a mixture of 4 and two rotameric 3-[N-(2-aminoethyl)-N-methylamino]-1,1-diphenyl-1,2-dihydropentalenes (5a) and (5b). Treatment of the lithium salt 3-Li with Me₃SiCl has lead to 3-{N-[2-(N-trimethylsilylamino)ethyl]amino}-1,1-diphenyl-1,2-dihydropent alene (6) as the dominant component in the reaction mixture. In the latter case the expected Me₃Si-C₅H₄CPh₂CH₂ -(1-Me-C₃H₄N₂) (3-Si) was not observed. Stannylation of 3-Li with 1 equiv. of Me₃SnCl has resulted in formation of a mixture of Me₃Sn-C₅H₄CPh₂CH₂ -(1-Me-C₃H₄N₂) (3-Sn), (Me₃Sn)₂-C₅H₃CPh₂ CH₂-(1-Me-C₃H₄N₂) (3-Sn₂), and cyclopentadiene 3-H in a ca. 2:1:1 molar ratio. Monocyclopentadienyl complexes {[η⁵:η¹-κN-C₅ H₄CPh₂CH₂-(1-Me-C₃H₄N ₂)]MCl₃ (M = Ti (7), Zr (8)) have been prepared starting from the organotin and organolithium compounds 3-Sn and 3-Li, respectively. The dynamic behavior of complexes 7 and 8 has been investigated by means of variable-temperature NMR spectroscopy in solutions. The molecular structures of the dihydropentalene 4, binuclear complex {[η⁵:η¹-κN-C₅ H₄CPh₂CH₂-(1-Me-C₃H₄N ₂)]ZrCl₂}₂(μ-Cl)₂ 8, and a coordination dimer of the dilithium salt 2a have been established by X-ray diffraction analysis. In the crystal structure of the 2a-dimer, the shortest known Li-Li contact has been found.

Full text of DOI:10.1016/j.jorganchem.2008.04.015

Journal of Organometallic Chemistry 693 (2008) 2355–2368
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
1-Methylimidazolin-2-yl functionalized cyclopentadienyl complexes
of titanium and zirconium. Crystal structure of
{[g5:g1-jN-C5H4CPh2CH2-(1-Me–C3H4N2)]ZrCl2}2(l-Cl)2
b
c
Wanli Nie a, Longyu Liao b,d, Wenqing Xu a,1, Maxim V. Borzov a,b, , Dmitrii P. Krut’ko , Andrei V. Churakov ,
*
Judith A.K. Howard e, Dmitri A. Lemenovskii b
a The North-West University of Xi’an, Department of Chemistry, Taibai Bei Avenue 229, Xi’an 710069, Shaanxi Prov., PR China
b M.V. Lomonosov Moscow State University, Department of Chemistry, Leninskie Gory, 119992 Moscow, Russia
c N.S. Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Science, Leninskii Prosp., 31, Moscow 119991, Russia
d Institute of Chemical Materials, CAEP, Mianyang 621900, PR China
e Department of Chemistry, University of Durham, South Road, Durham DH1 3LE, UK
a r t i c l e i n f o
a b s t r a c t
Article history:
The novel bidentate ligand, C5H4CPh2CH2-(1-Me–C3H4N2) (3), has been prepared and characterized as its
lithium salt LiC5H4CPh2CH2-(1-Me–C3H4N2) (3–Li). Cyclopentadiene HC5H4CPh2CH2-(1-Me–C3H4N2) (3–
H) has been obtained from 6,6-diphenylfulvene and 1,2-dimethylimidazoline (1). In THF-d8 solution in
the presence of 1, (1-methylimidazoline-2-yl)methyllithium (2) has been proved to undergo gradual con-
version into a dilithium derivative of N1-methyl-N2-[(1E,2E)-1-methyl-2-(1-methylimidazolidine-2-
idene)ethylidene]ethane-1,2-diamine (2a). In a solution, cyclopentadiene 3–H has been shown to
undergo isomerization into 3-{N-[2-(N-methylamino)ethyl]amino}-1,1-diphenyl-1,2-dihydropentalene
(4) and, further, into a mixture of 4 and two rotameric 3-[N-(2-aminoethyl)-N-methylamino]-1,1-diphe-
nyl-1,2-dihydropentalenes (5a) and (5b). Treatment of the lithium salt 3–Li with Me3SiCl has lead to 3-
{N-[2-(N-trimethylsilylamino)ethyl]amino}-1,1-diphenyl-1,2-dihydropentalene (6) as the dominant
component in the reaction mixture. In the latter case the expected Me3Si–C5H4CPh2CH2-(1-Me–
C3H4N2) (3–Si) was not observed. Stannylation of 3–Li with 1 equiv. of Me3SnCl has resulted in formation
of a mixture of Me3Sn–C5H4CPh2CH2-(1-Me–C3H4N2) (3–Sn), (Me3Sn)2-C5H3CPh2CH2-(1-Me–C3H4N2) (3–
Sn2), and cyclopentadiene 3–H in a ca. 2:1:1 molar ratio. Monocyclopentadienyl complexes {[g5:g1-jN-
C5H4CPh2CH2-(1-Me–C3H4N2)]MCl3 (M = Ti (7), Zr (8)) have been prepared starting from the organotin
and organolithium compounds 3–Sn and 3–Li, respectively. The dynamic behavior of complexes 7 and
8 has been investigated by means of variable-temperature NMR spectroscopy in solutions. The molecular
structures of the dihydropentalene 4, binuclear complex {[g5:g1-jN-C5H4CPh2CH2-(1-Me–C3H4N2)]-
ZrCl2}2(l-Cl)2 8, and a coordination dimer of the dilithium salt 2a have been established by X-ray diffrac-
tion analysis. In the crystal structure of the 2a-dimer, the shortest known Li–Li contact has been found.
Ó 2008 Elsevier B.V. All rights reserved.
Received 10 January 2008
Received in revised form 30 March 2008
Accepted 11 April 2008
Available online 16 April 2008
Keywords:
Zirconium
Titanium
Lithium
Cyclopentadienyl ligands
Imidazoline
Intramolecular coordination
1. Introduction
and is either in an sp3-hybridized state (N ? M coordination bond)
or in an sp2-hybridized state due to additional donation of the lone
The Group 4 transition metal complexes with cyclopentadienyl
ligands bearing a nitrogen-containing n-donor moiety in the side
chain have been extensively studied (see reviews [1–3]) and still
attract considerable attention [4–14]. In the most complexes of
this type, the nitrogen atom is bound to aliphatic substituents
electron pair to the metal atom (so-called geometry constrained
complexes). Complexes in which the N ? M coordination is pro-
vided by an sp2-hybridized nitrogen atom (aromatic or related aza-
heterocycle) are few and limited to pyridine or quinoline systems
[9,15–24] (i.e., to monoaza aromatic systems).
Consideration of 1,3-diazoles in this context seems to be top
intriguing. The presence of the second ‘‘external” nitrogen atom,
which is conjugated to the metal-linked nitrogen atom, provides
additional possibilities for control of the nitrogen–metal interac-
tions (for example, toggling between sp2- and sp3-hybridization
modes) and ‘‘fine tuning” of the p-donor–acceptor and r-donor
properties of the coordinating nitrogen atom.
* Corresponding author. Address: M.V. Lomonosov Moscow State University,
Department of Chemistry, Leninskie Gory, 119992 Moscow, Russia. Tel.: +7 095
9391234/+86 132 27799878; fax: +7 095 9328846.
E-mail address: maxborzov@mail.ru (M.V. Borzov).
A part of the Master Degree work at the Department of Chemistry of the North-
1
West University of Xi’an.
0022-328X/$ - see front matter Ó 2008 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2008.04.015

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W. Nie et al. / Journal of Organometallic Chemistry 693 (2008) 2355–2368
Ph
Li
Ph
Ph
Ph
N
N
N
n-BuLi
N
THF
hexane/THF
N
N
83%
97%
Li
1
2
3-Li
Scheme 1.
1,3-Diazoles seldom occur as N-donor ligands in organometallic
chemistry of the Group 4 metals (Arduengo carbenes are not con-
sidered in this context). The earliest works dating back to the
1960s [25,26] report preparation of 1:1 and 1:2 adducts of substi-
tuted imidazoles and benzimidazoles with MCl4 (M = Ti, Zr, Hf,
Th). Later in the middle of the 1980s a series of 1:1 binuclear imid-
azole adducts [MX4-(2-R–C3H2N2)]2 (M = Ti, Zr, R = H, Me) was pre-
pared [27]. However, no structural data on these complexes are
available. The first structurally characterized complexes of Ti and
Zr with imidazole-type ligands appeared comparatively recently.
To perform more detailed description of the ligand 3, the lith-
ium salt 3–Li was converted into cyclopentadiene 3–H by treat-
ment with methanol at 0–20 °C. As well as its imidazole analog
[31], 3–H represents a mixture of two isomers on positioning of
the double bonds in respect to the substituent (3–Ha:3–
Hb = 1:1.3, see Scheme 2). However, the other chemical features
of 3–H differ markedly from those of its imidazole analogue. Thus,
in its 1H NMR spectrum, the signals related to the Cp-ring hydro-
gens of the isomer 3–Ha are considerably broadened. This can be
explained by the reversible intramolecular deprotonation of the
Cp-ring in 3–Ha with the strongly basic imidazoline nitrogen (for
3–Hb such a process can be realized with difficulty, if at all).
Moreover, the cyclopentadiene 3–H is unstable thermally and,
if heated above 40 °C, turns quantitatively into substituted 1,
2-dihydropentalene 4. On further staying in a solution at room
temperature, compound 4 reversibly isomerizes into a mixture of
1,2-dihydropentalenes 5a and 5b, with the equilibrium establish-
ing after two weeks. Compounds 5a and 5b are rotamers in respect
to spinning around the C(3)–N bond which is cumbered due to
conjugation of the nitrogen lone pair with the C@C bond. Of inter-
est, both NMR (carbons C(3) and C(3a) are the quaternary ones)
and X-ray data (vide infra) indicate that dihydropentalene 4 exists
exclusively as an enamine. That may be due to the thermodynamic
preference of the fulvene-type system. For compound 4, rotamer-
izm around C(3)–N bond is not observed. All isomeric dihydropen-
talenes 4, 5a and 5b at room temperature are in an equilibrium one
with each other, with molar ratio 4:5a:5b being equal to 3.0:1.5:1
(NMR spectroscopy data).
These were
a dimeric dititanium complex [jN(3)-(1-Me3Si–
C3H2N2)TiCl3]2(l-Cl)2 [28] and dizirconium dihydroxyl bridged
zwitterionic complex [jN(3)-(1-(C6F5)3Bꢀ–C3H2N2)(g5-C5H5)2Zr+]2
(l-OH)2 prepared by hydrolysis from monomeric precursor
[jN(3)-(1-(C6F5)3Bꢀ–C3H2N2)(g5-C5H5)2Zr+Me] [29]. In the latter
publication the authors used imidazole moiety as a ‘‘spacer” be-
tween cationic and anionic centers of the zwitterionic system.
2-Methylimidazole was also applied as a ligand that successfully
competes for a coordination place even with a THF molecule for iso-
lation purposes (complexes [g5:g1-jP-C5H4CH2CH2P(2,4,6-Me3-
C6H2)][jN(3)-(1-Me3Si–C3H2N2)]MCl2 (M = Zr, Hf) [30]).
In our recent paper we reported preparation of the first imidazole
side chain functionalized cyclopentadienyl ligand C5H4CPh2CH2-
(1-Me–C3H2N2) in the forms of its Li-salt, CH-acid, and trimethyl-
silyl-derivative along with two monocyclopentadienyl titanium
and zirconium complexes derived from it [31].
However, while complexes of the Group 4 metals with imida-
zoles or related systems as N-ligands are known, imidazolines
have never been applied in this area of organometallic chemistry.
Meanwhile, the known greater basicity of imidazolines
(pK25a(2-Me–C3H6N+2) 11.1 [32]) comparatively to imidazoles
(pK25a(2-Me–C3H4N+2) 8.02 [33]), on one hand, and the greater
reactivity of the imidazoline moiety (possibility to accept nucleo-
philic attacks at the 2nd position and ring-opening reactions), on
the other, make them even somewhat more attractive than imida-
zoles for the purposes of coordination and organometallic chemis-
try of the Group 4 elements.
This paper describes preparation of the first imidazoline side-
chain functionalized ligand C5H4CPh2CH2-(1-Me–C3H4N2) (3), its
non-trivial properties and synthesis and structural investigations
of the half-sandwich complexes of titanium and zirconium com-
plexes based on it.
2.2. Crystal structure of 3-{N-[2-(N-methylamino)ethyl]amino}-1,1-
diphenyl-1,2-dihydropentalene (4)
Compound 4 was crystallized from a hexane solution of its equi-
librium mixture with 5a,b containing a small amount of methanol
as an adduct with one molecule of CH3OH. Molecular structure of 4
is depicted in Fig. 1, crystal structure of the adduct is presented in
Fig. 2. The selected bond lengths and angles are listed in Table 1.2
Both phenyl rings in 4 are disordered over several positions. The
cyclopentadienyl fragment C(4)–C(8) is planar within 0.005 Å, the
fulvene fragment C(1),C(4)–C(8) is planar within 0.006 Å. The
nitrogen atom N(1) is sp2-hybridized [valency angle sum at N(1)
equals 360(4)°]. The bond lengths C(1)–C(8) and C(1)–N(1)
(1.379(5) and 1.321(5) Å, respectively) indicates the enamine nat-
ure of 4 what is in a complete agreement with the NMR data for
solutions of 4.
2. Results and discussion
In crystal, the molecules of compound 4 and methanol assemble
in chains by the H(1)ꢁ ꢁ ꢁO(1) and H(3)ꢁ ꢁ ꢁN(2A) hydrogen bonds.
Likely, it is the presence of methanol in mother solution that pro-
vides the preference of the Z-conformer crystallization. Evidently,
2.1. Ligand synthesis
The functionalized cyclopentadienyl ligand 3 was prepared as
its lithium salt 3–Li by metallation of 1,2-dimethylimidazoline
(1) with n-BuLi in THF/hexane medium followed by a reaction of
(1-methylimidazoline-2-yl)methyllithium (2) with 6,6-diphenyl-
fulvene (Scheme 1). As for the imidazole analogue of 3–Li [31],
both salts 2 and 3–Li were isolated in pure state and characterized
by 1H and 13C NMR spectroscopy.
2
Numbering of atoms in the crystallographic section does not match the IUPAC
rules. For other sections of this paper the atom numbering given in corresponding
schemes is used.

W. Nie et al. / Journal of Organometallic Chemistry 693 (2008) 2355–2368
2357
Ph
Ph
Ph
Ph
Ph
Ph
1'
N
1'
N
N
2'
2'
2
1
1
2
MeOH
5'
5'
N
N
N
3
t < 20oC
5
3'
3'
5
3
4'
4'
Li
4
4
3-Hb
3-Li
3-Ha
intramolecular proton
transfer
Ph
Ph
Ph
Ph
N
HN
N
HN
Ph
Ph
Ph
Ph
NH
N
HN
H2N
Ph
Ph
Ph
Ph
1
6
Ph
Ph
6a
3a
2
5
3
4
NH
N
N
H2N
HN
5a
5b
H2N
4
Scheme 2.
the tendency of 4 to capture and retain methanol caused unsatis-
factory elemental analysis results obtained for 4.
Single crystal of compound 2a was grown up from the THF-d8
solution of organolithium compound 2 containing trace amounts
of imidazoline 1 in an NMR tube. Molecular structure of compound
2a was established by X-ray diffraction analysis and is presented in
Fig. 3 (ORTEP drawing). In Fig. 4, ball-and-stick drawing of 2a is
provided for clarification. The selected bond lengths and angles
for 2a are listed in Table 2.
In crystalline state, diamide 2a represents a centrosymmetric
coordination dimer and exists as an adduct with two molecules of
THF(-d8). In respect to each Li-atom, the organic part of the molecule
serves as an g3-jN,N,N-ligand, with the methyl group protected
nitrogen of the imidazoline moiety not participating in the coordina-
tion. Binding of the two parts of the molecule is provided by bonds
N(4)–Li(2) and N(4A)–Li(2A). The lithium atoms Li(1) and Li(2A)
are positioned on the opposite sides of the N(2),N(3),N(4) plane
2.3. Imidazoline ring-opening degradation of compound 2 and crystal
structure of the diamido-type product 2a
If not free from 1,2-dimethylimidazoline 1, organolithium com-
pound 2 in a THF-d8 solution gradually undergoes degradation and
interconverts into its formal dimer 2a (3 months, room tempera-
ture). As far as it is hardly believable that the C2 carbon in 2 can
accept any nucleophilic attacks this process of the imidazoline ring
opening, supposedly, may occur as it is depicted in Scheme 3 and is
catalyzed with non-deprotonated 1. Indeed, if presence of even the
traces of 1 is excluded, THF solutions of organolithium compound 2
are stable and no ring cleavage occurs.

2358
W. Nie et al. / Journal of Organometallic Chemistry 693 (2008) 2355–2368
remarkable feature of the 2a molecule. Analysis of the Cambridge
Structural Database (release: August 2007; 60 entries, 160 frag-
ments, Li–Li distance range 2.232–2.499 Å) [34] reveals that
Li(1)–Li(2A) contact is the shortest among ever observed. This con-
tact is remarkably shorter than the Li–Li distances in organolith-
ium clusters [Cambridge Structural Database (release: August
2007; 21 entries, 78 fragments, Li–Li distance range 2.342–
2.489 Å) [34]] and in earlier reported (l3-Me)4Li4 (2.56 Å) [35]
and closer to what is observed in lithium amides and polyamides
(2.252 Å [36], 2.281, 2.301 Å [37]; 2.232 Å [38]; 2.280 Å [39]).
However, it is considerably greater than the sum of the ionic radii
of two Li+ cations (1.18 Å for CNLi = 4 [40]). The fragment Li(1),-
Li(2),Li(1A),Li(2A),N(4),N(4A) (mean plane PL2) is planar within
0.05 Å, with the Li(1) and Li(1A) atoms deviating the most. Similar
assembling of lithium atoms and strongly electronegative hetero-
atoms (O, N, F) into a nearly planar moieties was observed earlier
[36–39,41,42].
As for the organic part of the molecule, the fragment
N(1),N(2),C(1),C(2) (mean plane PL3) is planar within 0.005 Å, with
the sum of the angles at C(1) being 359.99(54)°. Carbon atom C(3)
only slightly deviates from PL3 [0.0076(44) Å], while C(2)–PL3 and
C(5)–PL3 distances are considerably large [0.4291(51) and
0.4202(46) Å]. Thus, the imidazoline moieties of the molecule are
essentially non-planar and are in envelope conformations.
Carbon atom C(11) is also very close to the PL3 [0.0278(39) Å],
with the dihedral angle N(2)–C(1)–C(4)–C(11) being equal to
Fig. 1. Molecular structure of compound 4 (adduct with CH3OH 1:1). The methanol
molecule and hydrogen atoms are omitted for clarity.
(PL1), with the distance Li(1)–PL1 being ca. 0.05 Å shorter than
Li(2A)–PL1 [1.075(4) vs. 1.125(3) Å, respectively]. The ‘‘outer” Li(1)
atom is coordinated with an O(1) atom of the THF molecule. In re-
spect to electronegative atoms (O, N) all Li atoms exhibit CN = 4, with
Li(1) and Li(2A) sited very close to one of the faces of the respective
distorted tetrahedra [N(2),N(3),N(4),O(1); deviation of Li(1) from
N(2),N(4),O(1) plane 0.2891(40) Å; N(2),N(3),N(4),N(4A); deviation
of Li(2A) from N(2),N(4),N(4A) plane 0.2781(35) Å].
The presence of extremely close lithium–lithium contacts
[Li(1)–Li(2A) 2.201(5) Å and Li(2)–Li(2A) 2.396(6) Å] is the most
Fig. 2. Crystal structure of the adduct of 4 with one molecule of methanol. Hydrogen bonds are drawn as dashed lines. Hydrogen atoms linked to carbons are omitted for
clarity.

W. Nie et al. / Journal of Organometallic Chemistry 693 (2008) 2355–2368
2359
Table 1
Selected bond lengths (Å) and angles (°) for compound 4
N(1)–C(1)
N(1)–C(9)
N(1)–H(1)
N(2)–C(20)
N(2)–C(10)
N(2)–H(2)
C(1)–C(8)
C(1)–C(2)
C(2)–C(3)
C(3)–C(4)
C(4)–C(5)
C(4)–C(8)
C(5)–C(6)
C(6)–C(7)
C(7)–C(8)
C(9)–C(10)
1.321(5)
1.461(4)
0.91(4)
1.468(5)
1.470(4)
0.91(4)
1.379(5)
1.507(5)
1.555(6)
1.506(5)
1.377(6)
1.434(5)
1.430(5)
1.367(5)
1.431(5)
1.517(5)
C(1)–N(1)–C(9)
C(1)–N(1)–H(1)
C(9)–N(1)–H(1)
C(20)–N(2)–C(10)
C(20)–N(2)–H(2)
C(10)–N(2)–H(2)
N(1)–C(1)–C(8)
N(1)–C(1)–C(2)
C(8)–C(1)–C(2)
C(41)–C(3)–C(31)
C(5)–C(4)–C(8)
C(5)–C(4)–C(3)
C(8)–C(4)–C(3)
C(1)–C(8)–C(7)
C(1)–C(8)–C(4)
C(7)–C(8)–C(4)
N(1)–C(9)–C(10)
123.5(3)
116(2)
121(2)
113.2(3)
104(2)
111(2)
130.9(3)
119.7(3)
109.4(3)
93.2(8)
107.6(3)
140.1(3)
112.3(3)
142.1(3)
109.5(3)
108.3(3)
111.7(3)
Fig. 3. Molecular structure of a dimer of 2a (adduct with 2 molecules of THF-d8). All
hydrogen atoms are omitted for clarity. The thermal ellipsoids are shown at 50%
probability level.
0.5(4)° only. The next by the chain torsion angle C(1)–C(4)–C(11)–
N(3) is also small [9.13(35)°]. The C(11)–N(3) bond length
[1.300(2)] indicates its double nature. The bond lengths N(2)–
C(1), C(1)–C(4), C(4)–C(11) [1.330(2), 1.401(3), and 1.395(3) Å,
respectively] are in a range between single and double bond
lengths that is typical for conjugated systems with delocalized neg-
ative charge.
and conventional intermediate step in the Group 4 metal organoel-
ement chemistry. However, while the imidazole analogue of salt
3–Li, LiC5H4CPh2CH2-(1-Me–C3H2N2), gives the target silane
Me3Si–C5H4CPh2CH2-(1-Me–C3H2N2) in an excellent yield [31],
cyclopentadienide 3–Li reacted with Me3SiCl in an absolutely dif-
ferent manner and the desired silane 3–Si was not even observed
in the reaction mixture. The main product of this reaction is the
substituted 1,2-dihydropentalene 6 (ca. 60% in the isolated mixture
of the products, see Scheme 4). The suggested mechanism for for-
mation of 6 is given in Scheme 4, as well. The structure of dihydro-
pentalene 6 was established by 1H and 13C NMR spectroscopy and
mass spectrometry.
Trimethylstannylation of 3–Li with Me3SnCl (1:1 molar ratio)
also proceeds in a non-trivial manner and along with expected
stannane 3–Sn (ca. 50 mol.%) equimolar amounts of distannylated
(!) cyclopentadiene 3–Sn2 and cyclopentadiene 3–H (25 and
25 mol.%, NMR data, see Scheme 4). 1,2-Dihydropentalene-type
products analogous to 4, 5a,b and 6 were not observed. Monostan-
nylated compound 3–Sn was isolated in a mixture with 3–Sn2 and
3–H as yellow oil and this mixture was used for the further pur-
poses without the component separation.
As for the THF fragment, carbon atom C(22) and hydrogen
atoms H(22A,B), H(21A,B), and H(23A,B) (not depicted in Figs. 3
and 4) are disordered between two positions with the occupancies
0.44 (envelope conformation) and 0.56 (twisted conformation).
In THF-d8 solution, compound 2a exhibits dynamic behavior,
probably, due to monomerization–dimerization processes. Indeed,
in both 1H and 13C NMR spectra, the signals related to the end-of-
chain CH3–N-–CH2 amido-moiety are broadened the most (this
1
made accurate measurement of the JCH constants for C(70) and
1
C(50) impossible). All JCH constants for C(80), C(5), and C(40) are
of the normal value (135, 137, and 137 Hz, respectively), while
the ones for C(4) (129 Hz) and C(70) (126 Hz; measured as differ-
ence between the 13C satellites in 1H NMR spectrum) are consider-
13
ably lower. Both 1H and C chemical shifts for C(10) (3.78 and
1
73.86, respectively) along with rather high JCH (154 Hz) are in an
agreement with the retention of the chelating structure of the 2a
in a THF solution, as well.
The structure of the distannylated compound 3–Sn2 was estab-
lished by 1H and 13C NMR spectroscopy (3–Sn, 3–Sn2 and 3–H mix-
ture was investigated). The subspectra (both 1H and 13C) of
monostannylated cyclopentadiene 3–Sn exhibit all features typical
for monostannylated cyclopentadienes, with the signals related to
2.4. Trimethylsilylation and –stannylation reactions of lithium salt
3–Li
Conversion of alkali-metal cyclopentadienides into correspond-
ing trialkylsilyl and/or –stannyl derivatives is nowadays a routine
Li
N
LiN
N
N
THF
N
N
+
N
N
1
2
9'
2'
4'
1'
2
3'
N
N
NLi
N
5'
2
8'
N6'
Li
7'
N
-1
N
1
Li
3
N
2a
5
4
Scheme 3.

2360
W. Nie et al. / Journal of Organometallic Chemistry 693 (2008) 2355–2368
Fig. 4. Ball-and-stick drawing of a dimer of 2a (adduct with two molecules of THF-d8). All hydrogen atoms are omitted for clarity. Only the atoms participating in the
coordination interaction are labeled. View normal to PL2 [mean plane of the Li(1),Li(2),Li(1A),Li(2A),N(4),N(4A) fragment].
Table 2
The selected bond lengths (Å) and angles (°) for compound 2a
N(1)–C(1)
N(1)–C(2)
N(1)–C(5)
N(2)–C(1)
N(2)–C(3)
N(2)–Li(1)
N(2)–Li(2A)
N(3)–C(11)
N(3)–C(13)
N(3)–Li(1)
N(3)–Li(2A)
N(4)–C(14)
N(4)–C(15)
N(4)–Li(2)
N(4)–Li(2A)
N(4)–Li(1)
C(1)–C(4)
1.393(2)
1.442(3)
1.445(3)
1.330(2)
1.464(3)
2.052(4)
2.083(4)
1.300(2)
1.450(3)
2.028(4)
2.120(4)
1.445(3)
1.448(3)
2.012(4)
2.105(4)
2.107(4)
1.401(3)
1.514(3)
1.395(3)
1.515(4)
1.527(4)
2.201(5)
2.396(6)
1.908(4)
C(1)–N(1)–C(2)
C(1)–N(2)–C(3)
107.35(18)
107.30(17)
117.29(17)
125.13(17)
110.22(15)
127.2(2)
N(1)–C(2)–C(3)
N(2)–C(3)–C(2)
101.3(2)
104.6(2)
124.24(19)
120.8(2)
121.3(2)
118.0(2)
106.5(2)
110.6(2)
169.2(2)
60.01(14)
58.52(14)
58.46(13)
132.58(19)
108.87(15)
112.99(16)
129.02(19)
81.91(13)
77.57(14)
166.7(2)
57.15(13)
58.52(13)
55.93(14)
56.25(14)
155.7(3)
C(1)–N(2)–Li(1)
C(3)–N(2)–Li(1)
C(1)–N(2)–Li(2A)
C(3)–N(2)–Li(2A)
Li(1)–N(2)–Li(2A)
C(11)–N(3)–C(13)
C(11)–N(3)–Li(1)
C(13)–N(3)–Li(1)
C(11)–N(3)–Li(2A)
C(13)–N(3)–Li(2A)
Li(1)–N(3)–Li(2A)
C(14)–N(4)–C(15)
C(14)–N(4)–Li(2)
C(15)–N(4)–Li(2)
C(14)–N(4)–Li(2A)
C(15)–N(4)–Li(2A)
Li(2)–N(4)–Li(2A)
C(14)–N(4)–Li(1)
C(15)–N(4)–Li(1)
Li(2)–N(4)–Li(1)
Li(2A)–N(4)–Li(1)
N(2)–C(1)–N(1)
N(2)–C(1)–C(4)
C(11)–C(4)–C(1)
N(3)–C(11)–C(4)
N(3)–C(11)–C(12)
C(4)–C(11)–C(12)
N(3)–C(13)–C(14)
N(4)–C(14)–C(13)
O(1)–Li(1)–Li(2A)
N(3)–Li(1)–Li(2A)
N(2)–Li(1)–Li(2A)
N(4)–Li(1)–Li(2A)
N(4)–Li(2)–N(2A)
N(4)–Li(2)–N(4A)
N(2A)–Li(2)–N(4A)
N(4)–Li(2)–N(3A)
N(2A)–Li(2)–N(3A)
N(4A)–Li(2)–N(3A)
N(4)–Li(2)–Li(1A)
N(2A)–Li(2)–Li(1A)
N(4A)–Li(2)–Li(1A)
N(3A)–Li(2)–Li(1A)
N(4)–Li(2)–Li(2A)
N(2A)–Li(2)–Li(2A)
N(4A)–Li(2)–Li(2A)
N(3A)–Li(2)–Li(2A)
Li(1A)–Li(2)–Li(2A)
64.34(14)
123.9(2)
126.79(18)
108.20(18)
110.08(17)
102.42(18)
64.06(15)
108.6(2)
110.87(18)
97.68(17)
111.69(17)
139.5(2)
71.13(15)
90.68(17)
113.78(18)
133.92(16)
63.02(13)
111.81(18)
126.80(19)
121.38(17)
C(2)–C(3)
C(4)–C(11)
C(11)–C(12)
C(13)–C(14)
Li(1)–Li(2A)
Li(2)–Li(2A)
O(1)–Li(1)
52.62(13)
109.9(2)
111.0(2)
N(1)–C(1)–C(4)
Symmetry transformations used to generate equivalent atoms: ꢀx + 2, ꢀy, ꢀz + 1.
the Cp-ring –CH@ fragments averaged (AA0BB0 spin system, for
more detailed information on monostannylated cyclopentadienes
see review [43] and references cited therein). In the subspectra of
3–Sn2, all signals related to the Cp-ring –CH@ fragments are differ-
ent. The relative peak intensities of the 117/119Sn satellites (except
those of the Me3Sn-groups signals) in 13C NMR spectrum for the sig-
nals of 3–Sn2 are approximately two times greater than those for
the signals related to 3–Sn (the signal to noise ratio was not high
enough to make quantitative integration possible). For the 13C
NMR signal of the Me3Sn-group in 3–Sn2, two pairs of satellites
are observed (1J(C–119Sn) = 339 Hz, 3J(C–119Sn) = 4.3 Hz, SnMe3).
For compound 3–Sn2, the signal of the quaternary carbon of the
Cp-ring possesses a pair of satellites 117/119Sn (d = 51.37 ppm,
1J(C-119Sn) = 198 Hz). In the 1H and 13C NMR subspectra of 3–Sn2,
the observed relative intensity of the Me3Sn-group signals also
matches the presence of two trimethylstannyl moieties.
The formation of distannylated cyclopentadiene 3–Sn2, espe-
cially in such considerable amounts, is rather surprising. First of
all, it is a ‘‘sterically overhindered” molecule. Secondly, the mech-
anism of 3–Sn2 formation is not evident. In literature, no examples
of deprotonation of stannylated cyclopentadienes are known. Di-
and polystannylated cyclopentadienes can be prepared by a reac-
tion of stannylamines R3Sn–NR02 with corresponding CH-acidic
cyclopentadienes [44]. Consideration of these facts allows to sug-
gest the mechanism for the compound 3–Sn2 formation, as de-
picted in Scheme 5.

W. Nie et al. / Journal of Organometallic Chemistry 693 (2008) 2355–2368
2361
Ph
Ph
Ph
Ph
Ph
Ph
N
N
N
Me3SiCl
-LiCl
N
N
HN
3-Li
3-Si
Li
SiMe3
SiMe3
not observed
Ph
Ph
Ph
Ph
Ph
Ph
Me3Si
~SiMe3
~H
NH
Me3Si
N
N
dominating
product
HN
HN
H
Me3Si
6
allylic isomers
(only one is depicted)
N
vinylic isomers
Scheme 4.
It is worth mentioning here that compounds 4, 5a,b and 6
themselves can serve as precursors of new polydentate ligands
for organometallic chemistry. However, this should be a subject
for further investigations.
tain problems due to unavailability of silane 3–Si. Titanium and
zirconium complexes 7 and 8 were, however, prepared, starting
from 3–Sn (a 2:1:1 mixture with 3–Sn2 and 3–H) and 3–Li, respec-
tively (see Scheme 6). As it was expected, the yields of 7 and 8 were
lower than formerly observed for their imidazole analogues [g5:g1-
jN-C5H4CPh2CH2-(1-MeC3H2N2)]MCl3 (M = Ti, Zr) [31] what once
more illustrates the efficiency of application of the silylated cyclo-
pentadienes for preparation of monocyclopentadienyl complexes
of titanium and zirconium.
2.5. Preparation of titanium(IV) and zirconium(IV)
monocyclopentadienyl complexes 7 and 8
Unlike in case of the imidazole analogue of ligand 3 [31], syn-
thesis of complexes [g5:g1-jN-C5H4CPh2CH2-(1-MeC3H4N2)]TiCl3
(7) and [g5:g1-jN-C5H4CPh2CH2-(1-MeC3H4N2)]ZrCl3 (8) met cer-
Compounds 7 and 8 are both crystalline solids. Titanium complex
7 is red to orange (dependently on the size of the crystalline grains)
Ph
Ph
Ph
Cl
Ph
Ph
Ph
2'
1'
N
N
N
2
Me3SnCl
-LiCl
3
Me3SnCl
3'
N
N
5'
N
1
4'
3-Sn
~50%
Me3Sn
4
3-Li
5
Li
SnMe3
SnMe3
Ph
Ph
Ph
Ph
Cl
Ph
2'
1'
N
Ph
N
N
3
2
3-Li
5'
+
N
3'
N
1
-LiCl
HN
4'
4
5
3-H~25%
SnMe3
SnMe3
3-Sn2
SnMe3
SnMe3
~25%
Scheme 5.

2362
W. Nie et al. / Journal of Organometallic Chemistry 693 (2008) 2355–2368
Table 3
Ph
Ph
Selected bond lengths (Å) and angles (°) for compound 8
Ph
Zr(1)–N(1)
Zr(1)–Cl(3)
Zr(1)–Cl(2)
Zr(1)–Cl(1)
Zr(1)–Cl(1A)
N(1)–C(8)
N(2)–C(8)
Zr(1)–PLa
2.281(10)
2.466(4)
2.520(3)
2.592(4)
2.724(4)
1.278(15)
1.334(17)
2.205(6)
N(1)–Zr(1)–Cl(3)
N(1)–Zr(1)–Cl(2)
N(1)–Zr(1)–Cl(1)
Cl(3)–Zr(1)–Cl(1)
Cl(2)–Zr(1)–Cl(1)
Cl(3)–Zr(1)–Cl(2)
N(1)–Zr(1)–Cl(1A)
Cl(3)–Zr(1)–Cl(1A)
Cl(2)–Zr(1)–Cl(1A)
Cl(1)–Zr(1)–Cl(1A)
Zr(1)–Cl(1)–Zr(1A)
C(8)–N(1)–C(9)
84.4(3)
154.6(3)
83.2(3)
153.76(13)
90.78(13)
90.58(13)
78.6(3)
80.78(12)
76.09(12)
74.14(13)
105.86(13)
105.8(11)
131.8(9)
122.4(8)
117.0(12)
Ph
N
2'
ZrCl4
THF
1'
N
3'
N
Zr
N
Cl
Cl
5'
4'
Cl
Li
3-Li
8
M = Zr
20%
Me3SnCl
THF
Ph
Ph
Ph
C(8)–N(1)–Zr(1)
C(9)–N(1)–Zr(1)
N(1)–C(8)–N(2)
Ph
N
2'
TiCl4
a
1'
N
PL – mean plane of the Cp-ring.
3'
N
toluene
N
Ti
Cl
Cl
5'
ture-dependant 1H NMR spectra for 7 in CD2Cl2 and 8 in THF-d8 are
presented in Figs. 6 and 7, respectively.
Cl
4'
50%
3
Me3Sn
7
M =Ti 35%
+3-Sn2 + 3-H
Zirconium complex 8 in a THF-d8 solution exhibits dynamic
behavior similar to what observed formerly for its imidazole ana-
logue [g5:g1-C5H4CPh2CH2-(1-MeC3H2N2)]ZrCl3 [31]. At 55 °C,
compound 8 possesses the pseudo-Cs symmetry that vanishes
along with the temperature decrease due to slowing of the six-
member metallacycle –Zr–CCp–CPh2–CH2–C–N–(Zr) interconver-
sion. Analogous processes were observed previously for
(C5Me4CH2CH2SMe)ZrCl3 [45] and (C5Me4CH2CH2NMe2)ZrCl3 [12].
At ꢀ60 °C (the low-rate exchange limit), two pairs of the Cp-ring
protons, two pairs of the CH2–CH2 protons, bridge methylene
group protons and phenyl groups become non-equivalent. In 13C
NMR spectrum (ꢀ60 °C), Cp-ring carbons CH(2,5) and CH(3,4)
and the phenyl group carbons also become non-equivalent.
Within the range of ꢀ60 through +55 °C, the temperature drift
of the 13C NMR signals, except that for CH(2,5) cyclopentadienyl
carbons, does not exceed 0.5 ppm (at ꢀ60 °C the average shifts
for the corresponding pairs of the signals were considered). For
CH(2,5) cyclopentadienyl carbons the magnitude of this drift is
ca. 1 ppm that is also a regular value for the temperature drifts.
This agrees with the retention of the N ? Zr coordination within
all the temperature range studied.
Scheme 6.
while the zirconium complex 8 is nearly colorless. Formation of sta-
ble adducts with THF was not observed neither for 7 nor for 8.
2.6. Crystal structure of complex 8
Complex 8 is a centrosymmetric dimer with the Zr centers
linked one to another with two bridging chlorine atoms. The
molecular structure of 8 is depicted in Fig. 5. The selected bond
lengths and angles are listed in Table 3.
The coordination environment of the zirconium center is a dis-
torted octahedron (in an assumption that the Cp-ligand occupies
one coordination place). Three chlorine atoms and the non-methyl-
ated nitrogen atom of the imidazoline moiety occupy the equato-
rial positions while the Cp-ligand and one of chlorine atoms from
the environment of another Zr-center are located in the axial posi-
tions. This structural motif is rather typical for n-donor solvent free
zirconium half-sandwich cyclopentadienyl complexes [45–48]. In
general, complex 8 exhibits no remarkable quantitative or qualita-
tive structural particularities (CCDC, release August 2007 [34]).
The metallacycle inversion barrier for 8 was estimated by mea-
¼
suring the coalescence temperatures for CH(2,5) [DG = 49.6 ( 0.9)
(kJ/mol) = 11.9 ( 0.2) (kCal/mol), Tcoal = ꢀ13 °C], CH(3,4)
¼
2.7. NMR-studies of the fluxional behavior for complexes 7 and 8 in
solutions
[DG = 50.1 ( 0.9) (kJ/mol) = 12.0 ( 0.2) (kCal/mol), Tcoal = ꢀ25 °C],
¼
CH2(40) [DG = 49.7 ( 0.9) (kJ/mol) = 11.9 ( 0.2) (kCal/mol),
¼
Tcoal = ꢀ17 °C] and CH2(50) [DG = 49.6 ( 0.9) (kJ/mol) = 11.9 ( 0.2)
¼
The fluxional behavior of complexes 7 and 8 in solutions was
studied by variable-temperature NMR spectroscopy. The tempera-
(kCal/mol), Tcoal = ꢀ20 °C]. The average value DG = 49.8 ( 0.9) (kJ/
mol) = 11.9 ( 0.2) (kCal/mol). This is by 0.7 kCal/mol lower than
Fig. 5. Molecular structure of complex 8. All hydrogen atoms are omitted for clarity.

W. Nie et al. / Journal of Organometallic Chemistry 693 (2008) 2355–2368
2363
Fig. 6. Fluxional behavior of [g5:g1-C5H4CPh2CH2-(1-methylimidazolin-2-yl)]TiCl3 (7) in a CD2Cl2 solution.
¼
observed previously for the imidazole analogue of 8 [31]. The inter-
pretation of the cyclopentadienyl parts of the NMR spectra was per-
formed similarly to how it was done earlier [31].
and CH2CPh2 [DG = 46.8 ( 0.9) (kJ/mol) = 11.2 ( 0.2) (kCal/mol),
¼
Tcoal = ꢀ40 °C]. The average value DG = 46.5 ( 0.9) (kJ/
mol) = 11.1 ( 0.2) (kCal/mol). This value is by 0.8 kCal/mol lower
than for 8 and by 0.3 kCal/mol lower than observed previously
for the imidazole analogue of 7 in CD2Cl2 [31]. The low solubility
of 7 even in THF did not allow us to gain its 13C NMR spectrum.
Titanium complex 7, unlike its imidazole counterpart [g5:g1-
C5H4CPh2CH2-(1-MeC3H2N2)]TiCl3 [31], does not exhibit the
reversible intramolecular coordination–dissociation of the imidaz-
oline functionality towards the metal center in a solvating solvent
(THF-d8). Thus, its dynamic behavior in THF-d8 is fully analogous to
that of 8.
3. Experimental
The metallacycle inversion barrier for 7 was estimated by mea-
3.1. General remarks
¼
suring the coalescence temperatures for CH(2,5) [DG = 46.4 ( 0.9)
(kJ/mol) = 11.1
( 0.2)
(kCal/mol),
Tcoal = ꢀ35 °C],
CH2(40)
All procedures were performed in sealed-off evacuated glass
vessels. The employed solvents (and their perdeuterated ana-
¼
[DG = 46.4 ( 0.9) (kJ/mol) = 11.1 ( 0.2) (kCal/mol), Tcoal = ꢀ37 °C]

2364
W. Nie et al. / Journal of Organometallic Chemistry 693 (2008) 2355–2368
Fig. 7. Fluxional behavior of [g5:g1-C5H4CPh2CH2-(1-methylimidazolin-2-yl)]ZrCl3 (8) in a THF-d8 solution.
logues) were dried with and distilled from conventional agents
(namely: diethyl ether and THF, with sodium benzophenone ketyl,
benzene, toluene and hexane, with Na–K alloy, CH2Cl2 and with
CaH2). The degassed solvents were stored in evacuated reservoirs
over corresponding drying agent and transferred on a high-vacuum
line (the residual pressure of non-condensable gases of 10ꢀ3 torr or-
der) directly into reaction vessels by trapping them with liq. N2. The
operations with volatile reagents were performed similarly [Me3SiCl
(over Al powder), MeOH (over (MeO)2Mg)]. 6,6-Diphenylfulvene
was prepared as described previously [49]. 1,2-Dimethylimidazo-
line (1) was prepared from N-methylethylenediamine by an analogy
to [50]. TiCl4 was distilled under dry Ar atmosphere, heated under
reflux with freshly prepared reduced copper powder, degassed on
the high-vacuum line and packed by recondensation into
weighed-up glass receivers, that were then sealed off (Teflon grease
for joints was applied). ZrCl4 was sublimed in the stream of dry
hydrogen prior to use. For all compounds except 2a, 1H and 13C
NMR spectra were recorded on a Bruker Avance-400 spectrometer
at 400 and 100 MHz, respectively. 1H and 13C NMR spectra for com-
pound 2a were measured on a Bruker Avance 500 instrument at 500
and 125 MHz, respectively. For 1H and 13C spectra, the solvent
resonances [dH = 7.15 and dC = 128.0 (C6D6), dH = 1.73 and dC = 25.3
(THF-d8), and dH = 5.32 and dC = 53.8 (CD2Cl2)] were used as internal
reference standards. The calibration of the temperature controller

W. Nie et al. / Journal of Organometallic Chemistry 693 (2008) 2355–2368
2365
was performed by measuring the standard methanol sample spec-
tra. Mass spectra were measured on Finnigan MAT SSQ 7000 chro-
mato-mass spectrometer. The elemental analyses were performed
on the Carlo-Erba automated analyser.
dryness once more. The product was washed with hexane
(3 ꢂ 20 mL) and dried on the high vacuum line. Light-green pow-
der. Yield 1.98 g (96.9%). 1H NMR (THF-d8, 30 °C): d = 2.63 (s, 3H,
3
NCH3), 3.14, 3.35 (both t, 2H, JHH = 9.6 Hz, NCH2CH2N), 3.23 [s,
3+4
2H, CH2(7)], 5.51, 5.68 (both virt. t, 2H,
J
HH
= 5.4 Hz, C5H4),
3.2. (1-Methylimidazolin-2-yl)methyllithium (2)
7.01 (m, 2H, p-CH), 7.09 (m, 4H, m-CH), 7.23 (m, 4H, o-CH).
13C-{1H} NMR (THF-d8, 30 °C): d = 33.36 (NCH3), 40.07 [CH2(7)],
51.98, 52.80 (NCH2CH2N), 54.17 (CPh2), 103.29, 104.78 (CH in
C5H4), 121.75 (C in C5H4), 125.58 (p-CH), 127.50 (m-CH), 130.06
(o-CH), 152.22 (i-C), 169.81 (@NCN).
To a solution of 1,2-dimethylimidazoline (1) (1.77 g, 18.0 mmol)
in THF (10 mL), n-BuLi (10 mL of 2.45 M solution in hexane,
24.5 mmol, 35% excess) and diethyl ether (15 mL) were added at
ꢀ20 °C and vigorous shaking of the reaction mixture that caused
nearly immediate formation of white thin-crystalline voluminous
precipitate. The reaction mixture was allowed to warm up to room
temperature, stirred at room temperature for 4 h and left to stay
overnight. The yellow liquor was removed by filtering, the white
precipitate was washed on a filter with ether (3 ꢂ 10 mL) and dried
in high vacuum that gave 0.64 g of the organolithium compound 2
as white crystalline powder. Concentrating of the mother liquor and
etheral washings allowed to isolate additionally 0.93 g of the prod-
uct. Total yield 1.57 g (83.4%). NMR 1H (THF-d8, 30 °C): d = 1.93
(broad s, 2H, CH2Li), 2.56 (s, 3H, NCH3), 2.88, 3.26 (both t, 2H,
3JHH = 6.5 Hz, NCH2CH2N). 13C (THF-d8, 30 °C): d = 35.94 (q,
3.5. [2-(1-Methylimidazolin-2-yl)-1,1-diphenylethyl]cyclopentadiene
(3–H) (a mixture of isomers.)
Salt 3–Li (0.59 g, 1.76 mmol) was dissolved in a small amount of
methanol (5 mL). Methanol was removed by trapping into a vessel
cooled with liq. N2, the residue was extracted with hexane
(3 ꢂ 5 mL) and the hexane extract was evaporated and dried on
the high-vacuum line that gave 3–H as a yellow crystalline solid in
an almost quantitative yield. At all steps of the reaction and isolation
procedure the temperature was kept below 20 °C. 1H NMR (C6D6,
30 °C): d = 1.63 [s, NCH3(a)], 1.79 [s, NCH3(b)], 2.54, 3.42 [both t,
1
3
1JCH = 133 Hz, NCH3), 36.46 (t, JCH = 152 Hz, CH2Li), 49.70 [t,
3JHH = 9.6 Hz, NCH2CH2N(b)], 2.55, 3.45 [both t, JHH = 9.6 Hz,
1
3
1JCH = 136 Hz, NCH2(4)], 56.47 [tq, JCH = 136 Hz, NCH2(5)], 172.91
NCH2CH2N(a)], 2.75 [q, JHH = 4JHH = 1.5 Hz, CH2(5)(b)], 3.18 [br s,
(s, @NCN).
CH2(7)(a)], 3.19 [s, CH2(5)(a)], 3.32 [s, CH2(7)(b)], 6.19 (2H), 6.54
(1H) [both m, @CH(1, 3, 4)(b)], 6.25, 6.39, 6.45 [all br m, @CH(2, 3,
4)(a)], 7.00–7.16 [a set of m, m-, p-CH(a, b)], 7.38 [m, o-CH(a)],
7.51 [m, o-CH(b)]. 13C–{1H} NMR (C6D6, 30 °C): d = 32.52 [NCH3(a)],
33.02 [NCH3(b)], 36.55 [CH2(7)(b)], 36.95 [CH2(7)(a)], 40.92
[CH2(5)(b)], 43.05 [CH2(5)(a)], 52.58, 52.71, 52.80 (2C)
[NCH2CH2N(a, b)], 54.29 [CPh2(b)], 55.33 [CPh2(a)], 126.35 [p-
CH(a, b)], 127.69 [m-CH(a, b)], 128.05, 132.47, 135.47 [@CH(1, 3,
4)(b)], 129.61, 131.62, 132.87 [@CH(2, 3, 4)(a)], 129.77 [o-CH(a)],
130.04 [o-CH(b)], 146.05 [i-C(b)], 147.14 [i-C(a)], 153.10
[@C(2)(b)], 155.05 [@C(1)(a)], 163.78 [@NCN(b)], 163.82
[@NCN(a)]. Isomer ratio 3–Hb:3–Ha is 1.3. The numbering is given
in Scheme 2. GC/MS (EI, 70 eV, 70–290 °C), m/z (%): 328 [M]+ (0.4),
231 [C5H5CPh2]+ (18.6), 230 [C5H4CPh2]+ (100), 153 [C5H4CPh]+
(7.2), 84 [C3N2H5Me]+ (7.5), 77 [Ph]+ (3.3). Calc. for C23H24N2: C,
84.11; H, 7.36; N, 8.53. Found: C, 82.00; H, 7.81; N, 8.05%. The lower
content of carbon and the higher content of hydrogen can be ex-
plained by the presence of methanol. Thus, calc. for a 1:1 adduct
3.3. Dilithium salt of N1-methyl-N2-[(1E,2E)-1-methyl-2-
(1-methylimidazolidine-2-idene)ethylidene]-ethane-1,2-diamine (2a)
A solution of 2 in THF-d8 containing small amount of non-
deprotonated imidazoline 1 was kept at an ambient temperature
(25–35 °C) in sealed-off evacuated NMR tubes for 3 months.
Well-formed colorless single crystals grew on the bottom of the
tube. The first NMR tube was opened in a glove box under Ar atmo-
sphere, the single crystal for X-ray analysis was picked up and
mounted inside a Lindemann glass capillary that was sealed off.
The second tube was opened under high vacuum, the mother
liquor was removed from the crystals of 2a by decantation, the
crystals were washed with THF-d8, re-dissolved in the same THF-
d8 (THF-d8 was transferred by re-condensations) and the solution
was placed into the new NMR tube that was sealed off. Numbering
of atoms in 2a is provided in Scheme 3. NMR 1H (THF-d8, 25 °C):
1
d = 1.79 (broadened s, 3H, JCH = 125 Hz, CH3(90)), 2.59 (broad s,
C
23H24N2 ꢁ CH3OH: C, 79.96; H, 7.83; N, 7.77 element content is in
1
1
3H, JCH = 126 Hz, CH3(70)), 2.61 (broadened s, 3H, JCH = 132 Hz,
better agreement with the found values.
3
CH3(80)), 2.83 (broadened t, 2H, JHH = 4.7 Hz, CH2(50)), 2.94 (t,
3
2H, JHH = 8.0 Hz, CH2(4)), 3.30–3.39 (overlapped broadened t,
3.6. The 1,2-dihydropentalene-type products of cyclopentadiene 3–H
rearrangement (a mixture of isomeric 4, 5a and 5b)
2H + 2H, CH2(5) and CH2(40)), 3.78 (broadened s, 1H, 1JCH = 154 Hz,
CH(10)). 13C (THF-d8, 25 °C): d = 19.91 (q, JCH = 126 Hz, CH3(90)),
1
1
35.17 (q, JCH = 135 Hz, C(80)), 44.03 (broad q, C(70)), 50.68 (t,
Heating of the cyclopentadiene 3–H solution in C6D6 above 40 °C
for 20 min afforded quantitative formation of substituted 1,2-dihy-
dropentalene 4. On further staying in the solution at room temper-
ature, compound 4 reversibly isomerized into a mixture of 1,
2-dihydropentalenes 5a and 5b, with the equilibrium established
after two weeks. The numbering of atoms in the dihydropentalene
moiety is given in Scheme 2. Isomer 4 1H NMR (C6D6, 27 °C):
d = 0.04 (broad, 1H, NHCH3), 1.92 [s, 3H, NHCH3], 2.14 (broadened
s, 2H, CH3NHCH2), 3.04 [broadened s, 2H, CH2NHC(3)], 3.42 (s,2H,
CH2CPh2), 5.39 [broad, 1H, HNC(3)], 6.30 [s, 1H, H(6)], 6.42 [d, 1H,
3JHH = 4.4 Hz, H(4 or 5)], 7.14 [1H, overlaps with m-CH and C6D5H,
1JCH = 137 Hz, C(5)), 50.94 (t, JCH = 129 Hz, C(4)), 54.63 (t,
1
1JCH = 137 Hz, C(40)), 62.70 (broad t, C(50)), 73.86 (d, JCH = 154 Hz,
1
C(10)), 167.64, 171.80 (C(2), C(20)).
3.4. Lithium [2-(1-methylimidazolin-2-yl)-1,1-
diphenylethyl]cyclopentadienide (3–Li)
To a red solution of 6,6-diphenylfulvene (1.43 g, 6.21 mmol) in
THF (20 mL), the lithium salt 2 (0.63 g, 6.05 mmol) was added un-
der vigorous shaking and cooling at 0 °C. The color of the reaction
mixture immediately changed to dark-green. The solution was
heated at 35–45 °C for 2 days. The completeness of the reaction
was monitored by measuring the 1H NMR spectra of the control
sample in THF-d8. Concentrating of the solution till dryness gave
the crude product as green solidified foam soluble in ether and tol-
uene. To remove THF completely, the product was dissolved in tol-
uene (20 mL) and the resultant solution was evaporated till
H(5 or 4)], 7.01 (m, 2H, p-CH), 7.12 (m, 4H, m-CH), 7.45 (d, 4H,
1
3JHH = 7.6 Hz, o–CH). 13C NMR (C6D6, 27 °C): d = 35.64 (q, JCH
=
1
133 Hz, NCH3), 44.46, 49.31 (both t, JCH = 139 Hz, NCH2CH2N),
1
54.53 (s, CPh2), 57.00 [t, JCH = 130 Hz, CH2CPh2], 107.22 (d,
1JCH = 167 Hz), 112.01 (d, JCH = 164 Hz), 131.59 (d, JCH = 160 Hz)
1
1
1
[CH(4, 5, 6)], 121.44 [s, C(3a)], 125.90 (d, JCH = 160 Hz, p-CH),
128.23, 128.28 (both d, JCH = 158 Hz, m-, o-CH), 149.48 (s, i-C),
1

2366
W. Nie et al. / Journal of Organometallic Chemistry 693 (2008) 2355–2368
153.40, 157.14 [both s, C(3, 6a)]. Isomers 5a and 5b in a mixture
with 4 (aliphatic part of the spectra; the low-field signals of 5a
and 5b overlap with those of 4). 1H NMR (C6D6, 27 °C): d = 0.11
[broad, NH2 (5a)]; 0.32 [broad, NH2 (5b)]; 2.07 [broadened. qint,
3JHH = 6.0 Hz, CH2NH2 (5a)]; 2.22 [c, NCH3 (5b)]; 2.48 [broadened
t, 3JHH = 6.0 Hz, CH2NCH3 (5a)]; 2.54 [broad, CH2NH2 (5b)]; 2.65 [s,
NCH3 (5a)]; 3.05 [overlaps with CH2NHC(3) of 4, CH2NCH3 (5a)];
3.61 [s, CH2CPh2 (5b)]; 3.76 [s, CH2CPh2 (5a)].
(3–Sn2)], 52.75, 52.90 [NCH2CH2N (3–Sn)], 52.93, 52.95 [NCH2CH2N
(3–Sn2)], 54.57 [CPh2 (3–Sn)], 54.63 [CPh2 (3-Sn2)], 90.91 [broad-
ened s, JCSn = 55 Hz, CH(4, 5) (3–Sn)], 125.96 [p-CH (3–Sn2)],
126.03 [p-CH (3–Sn)], 127.44 [m-CH (3–Sn, 3–Sn2)], 127.91
[CH(1, 3) (3–Sn)], 129.44 [3JCSn = 25 Hz, CH(3) (3–Sn2)], 130.24
[o-CH (3–Sn2)], 130.36 [o-CH (3–Sn)], 132.80 (2JCSn = 12 Hz),
135.03 (2JCSn = 11 Hz) [CH(1, 4) (3–Sn2)], 147.75 [i-C (3–Sn)],
148.25 [i-C (3–Sn2)], 148.70 [3JCSn = 24 Hz, C(2) (3–Sn)], 149.00
[3JCSn = 27 Hz, C(2) (3–Sn2)], 163.87 [@NCN (3–Sn)], 163.92 [@NCN
(3–Sn2)].
1
3.7. Silylation of cyclopentadienide 3–Li (1,2-dihydropentalene-type
product 6)
3.9. [g5:g1-C5H4CPh2CH2(1-MeC3H4N2)]TiCl3 (7)
To a solution of Me3SiCl (0.34 mL, 0.27 g, 2.69 mmol) in THF
(20 mL) kept at ꢀ20 °C, the lithium salt 3–Li (0.90 g, 2.69 mmol)
was added. The resultant red slurry was allowed to warm up to
room temperature, stirred for 2 h and left to stay overnight. The sol-
vent was removed by trapping into a vessel cooled with liq. N2, the
residual red foam was extracted with hexane (15 mL), the extract
was concentrated and dried on the high-vacuum line that gave
0.88 g (82%) of 6 along with its minor isomers (1H NMR estimated
content of 6 is ca. 60%). The numbering of the atoms in the dihydro-
pentalene moiety is given in Scheme 2. 1H NMR (C6D6, 27 °C):
d = 0.04 (s, 9H, SiMe3), 2.17 (s, 3H, NCH3), 2.61 (t, 2H, 3JHH = 6.0 Hz,
CH2NCH3), 3.18 (q, 2H, 3JHH = 6.0 Hz, CH2NH), 3.55 (s, 2H, CH2CPh2),
To a solution of a mixture of 3–Sn, 3–Sn2 and 3–H (molar ratio
2:1:1, total amount 0.21 g, 0.43 mmol of stannanes) in toluene
(7 mL), a solution of TiCl4 in toluene (0.7 mL containing 0.06 g,
0.32 mmol of TiCl4) was added at room temperature. The color of
the solution turned dark-green. In a day, the color of the reaction
mixture changed to orange-red and orange precipitate formed.
The reaction mixture was stirred at room temperature for 3 addi-
tional days, the mother liquor was decanted, the precipitate was
washed with toluene (3 ꢂ 7 mL) and dried on the high-vacuum line
that gave 0.1 g (65%) of a crude product. Double recrystallization
from THF (ca. 5 mL) gave 0.06 g (39%) of pure 7. Fine-crystalline
powder. The numbering is given in Scheme 6. 1H NMR (THF-d8,
3
4.98 (broadened t, 1H, JHH = 5.0 Hz, NH), 6.26 [broadened s, 1H,
3
3
CH(6)], 6.48 [d, 1H, JHH = 4.3 Hz, CH(4 or 5)], 7.08 [overlaps with
27 °C): d = 3.03 (s, 3H, NCH3), 3.54 [t, 2H, JHH = 10.0 Hz, CH2(50)],
the signals of Ph, 1H, CH(5 or 4)], 7.00–7.16 (a set of m, 6H, m-, p-
CH), 7.47 (m, 4H, o-CH). 13C NMR (C6D6, 27 °C): d = 0.88 (q,
1JCH = 118 Hz, 1JCSi = 56.8 Hz, SiMe3), 33.83 (q, 1JCH = 134 Hz, NCH3),
43.25 (t, 1JCH = 138 Hz, CH2N), 48.27 (t, 1JCH = 134 Hz, CH2N), 54.51
(s, CPh2), 57.48 (t, 1JCH = 130 Hz, CH2CPh2), 107.17 (d, 1JCH = 167 Hz),
3.69 (s, 2H, CH2CPh2), 4.24 [t, 2H, 3JHH = 10.0 Hz, CH2(40)], 6.71 [vir-
3+4
3+4
tual t, 2H,
J
= 5.5 Hz, CH(3, 4)], 6.86 [virtual t, 2H,
J
HH
=
HH
5.5 Hz, CH(2, 5)], 7.13 (m, 4H, o-CH), 7.23 (m, 6H, m-, p-CH). 1H
NMR (THF-d8, ꢀ70 °C): d = 3.15 (s, 3H, NCH3), 3.52, 3.66 [both
broadened m, 1H, CH2(50)], 3.76 (A-part of an AB-system, 1H,
2JHH = 15.0 Hz, CHHCPh2), 3.95 (B-part of an AB-system,
1
1
111.94 (d, JCH = 164 Hz), 131.85 (d, JCH = 160 Hz) [CH(4, 5, 6)],
1
2
121.25 [s, C(3a)], 125.95 (d, JCH = 160 Hz, p-CH), 128.22, 128.28
(both d, JCH = 159 Hz, m-, o-CH), 149.39 (s, i-C), 153.63, 156.94
1H, JHH = 15.0 Hz, CHHCPh2), 4.00, 4.30 [both broadened m, 1H,
1
CH2(40)], 6.74 [broadened s, 1H, CH(4)], 6.79 [broadened s, 2H,
+
3
[both s, C(3, 6a)]. GC/MS (EI, 70 eV, 70–290 °C), m/z (%): 401 [M]
CH(3), CH(5)], 7.07 [broadened d, 2H, JHH = 7.6 Hz, o-CH], 7.14
(0.1), 328 [MꢀSiMe3]+ (2.0), 303 [MꢀMe2SiCH2ꢀC2H2]+ (27.3), 302
[MꢀSiMe3ꢀC2H2]+ (83.9), 288 [MꢀMe2SiCH2ꢀC2H2ꢀCH3]+ (19.4),
287 [MꢀSiMe3ꢀC2H2ꢀCH3]+ (67.9), 231 [C5H5CPh2]+ (11.0), 230
[C5H4CPh2]+ (52.2), 147 [(SiMe3)2H]+ (100), 91 [C7H7]+ (62.9), 73
[Me3Si]+ (29.9), 59 [Me2SiH]+ (8.2).
[broadened m, 3H, o-CH, CH(2)], 7.23 (broadened m, 4H, m-CH),
7.30 (broadened m, 2H, p-CH). Calc. for C23H23Cl3N2Ti: C, 57.35;
H, 4.81; N, 5.82. Found: C, 57.54; H, 4.71; N, 6.02%.
3.10. [g5:g1-C5H4CPh2CH2(1-MeC3H4N2)]ZrCl3 (8)
3.8. Stannylation of cyclopentadienide 3–Li (mono- and distannylated
compounds 3–Sn and 3–Sn2)
To a solution of ZrCl4 ꢁ 2THF (0.50 g, 1.33 mmol) in THF (40 mL), a
solution of the lithium salt 3–Li (0.46 g, 1.38 mmol) in THF (30 mL)
was added during 15 min under vigorous stirring and cooling
(ꢀ10 °C). The reaction mixture was then kept in a refrigerator at
ꢀ18 °C for 15 h. The solution was decanted from the white precipi-
tate and concentrated that gave a yellow oil. On drying of the oil was
on the high-vacuum line, toluene (0.5 mL) was added, the mixture
was homogenized and the solvent was removed in high vacuum.
The dry residue (a yellow powdered solid foam) was washed with
toluene (4 ꢂ 15 mL) and dried on the high-vacuum line that gave
0.43 g of crude product. Recrystallization from dichloromethane
(10 mL) gave 0.14 g (20%) of pure compound 8 as yellow crystals.
The numbering is provided in Scheme 6. 1H NMR (THF-d8, 55 °C):
To a solution of the salt 3–Li (0.25 g, 0.75 mmol) in diethyl ether
(15 mL), Me3SnCl (0.14 g, 0.70 mmol) was added and the reaction
mixture was stirred at room temperature for 1 h. The brownish-
red solution was decanted from the precipitated LiCl, ether was re-
moved by trapping into a liq. N2 cooled vessel and the residual oil
was dried on the high-vacuum line that gave red solidified foam
(0.21 g, 61%). The NMR spectroscopy data indicate the presence of
mono- and distannylated derivatives 3–Sn and 3–Sn2 along with
cyclopentadiene 3–H in a ca. 2:1:1 ratio. The numbering is given
in Scheme 5. Compounds 3–Sn and 3–Sn2. 1H NMR (C6D6, 27 °C):
d = ꢀ 0.13 [s, 2JHSn = 53.0 Hz, SnMe3 (3–Sn)], 0.04 [s, 2JHSn = 53.0 Hz,
3
d = 2.40 (s, 3H, NCH3), 3.29 [t, 2H, JHH = 10.3 Hz, CH2(50)], 3.63 (s,
3
3
SnMe3 (3–Sn)], 1.77 [s, NCH3 (3–Sn, 3–Sn2)], 2.55 [t, JHH = 9.6 Hz,
2H, CH2CPh2), 4.05 [t, 2H, JHH = 10.3 Hz, CH2(40)], 6.40 [virtual t,
3+4
3+4
NCH2(50) (3–Sn, 3–Sn2)], 3.45 [m, NCH2(40), CH2CPh2 (3–Sn, 3–
2H,
J
= 5.7 Hz, CH(3, 4)], 6.57 [virtual t, 2H,
J
HH
= 5.7 Hz,
HH
2
Sn2)], 5.12 [broadened s, JHSn = 45 Hz, CH(4, 5) (3–Sn)], 6.41 [dd,
CH(2, 5)], 7.18–7.29 (a set of m, 10H, Ph). 13C–{1H} NMR (THF-d8,
55 °C): d = 32.85 (NCH3), 39.02 (CH2CPh2), 52.20, 54.10 (NCH2CH2N),
52.28 (CPh2), 116.92 [CH(3, 4)], 123.53 [CH(2, 5)], 127.55 (p-CH),
128.78 (m-CH), 129.45 (o-CH), 133.32 [C(1)], 147.07 (i-C), 170.44
(@NCN). 1H NMR (THF-d8, ꢀ60 °C): d = 2.16 (s, 3H, NCH3), 3.07,
3.41 [both broadened m, 1H, CH2(50)], 3.62 (AB-system, 2H,
2JHH = 13.0 Hz, CH2CPh2), 3.76, 4.19 [both broadened m, 1H,
CH2(40)], 6.23 [broadened s, 2H, CH(4), CH(5)], 6.40 [broadened s,
1H, CH(3)], 6.89 [broadened s, 1H, CH(2)], 7.24–7.36 (a set of m,
4
3JHH = 4.5 Hz, JHH = 2.6 Hz, CH(4) (3–Sn)], 6.58 [broadened s,
3
CH(1, 3) (3–Sn), CH(1) (3–Sn2)], 6.84 [dd, JHH = 4.5 Hz,
4
4JHH = 1.3 Hz, JHSn = 9.0 Hz, CH(3) (3–Sn2)], 7.04 [m, p-CH (3–Sn,
3–Sn2)], 7.15 [m, m-CH (3–Sn, 3–Sn2)], 7.61 [m, o-CH (3–Sn,
3–Sn2)]. 13C–{1H} NMR (C6D6, 27 °C): d = ꢀ 8.46 [1JC–119Sn = 339 Hz,
3
JCSn = 4.3 Hz, SnMe3 (3–Sn2)], ꢀ8.30 [1JC–119Sn = 335 Hz, SnMe3 (3–
Sn)], 33.01 [NCH3 (3–Sn)], 33.10 [NCH3 (3–Sn2)], 36.91 [CH2CPh2
(3–Sn)], 37.31 [CH2CPh2 (3–Sn2)], 51.37 [1JCꢀ119Sn = 198 Hz, C(5)

W. Nie et al. / Journal of Organometallic Chemistry 693 (2008) 2355–2368
2367
10H, Ph). 13C-{1H} NMR (THF-d8, ꢀ60 °C): d = 32.49 (NCH3), 38.77
(CH2CPh2), 51.99 (CPh2), 52.03, 54.52 (NCH2CH2N), 114.19, 118.41
[CH(3, 4)], 122.21, 126.88 [CH(2, 5)], 127.41, 128.19 (p-CH),
128.77 (m-CH), 129.22, 130.33 (o-CH), 133.07 [C(1)], 144.43,
149.39 (i-C), 170.93 (@NCN). 1H NMR (CD2Cl2, 27 °C): d = 2.86 (s,
empirically from equivalents [52]. All structures were solved by di-
rect methods [53] and refined by full matrix least-squares on F2
[54]. In the structure of 4, all non-hydrogen atoms (except disor-
dered phenyl groups) were refined anisotropically. In 8, only Zr
and chlorine atoms were refined anisotropically due to the lack
of data (HKLF 5). In case of compound 4, amine hydrogen atoms
were found from difference Fourier synthesis and refined in an iso-
tropic approximation; all others were refined using a riding model.
In case of complex 8, all hydrogen atoms were placed in calculated
positions and refined using a riding model. In case of lithium salt
2a, all hydrogen atoms except those of disordered THF were found
from difference Fourier synthesis and refined in an isotropic
approximation; hydrogen atoms of the disordered THF molecule
were placed in calculated positions and refined using a riding
model. The rest of the crystal and structure refinement data is
listed in Table 4.
3
3H, NCH3); 3.52 (s, 2H, CH2CPh2); 3.55 [t, 2H, JHH = 10.1 Hz,
CH2(50)]; 4.13 [t, 2H, 3JHH = 10.1 Hz, CH2(40)]; 6.56, 6.72 [both virtual
t, 2H, 3+4JHH = 5.6 Hz, CH(2-5)]; 7.07 (m, 4H, o-CH); 7.29 (m, 6H, m-,
p-CH). 13C–{1H} NMR (CD2Cl2, 27 °C): d = 33.79 (NCH3); 38.80
(CH2CPh2); 51.29 (CPh2); 52.34 (2C, NCH2CH2N); 118.26, 118.34
[CH(2-5)]; 127.65 (p-CH); 128.46, 128.78 (o-, m-CH); 136.25
[C(1)]; 145.86 (i-C); 168.60 (@NCN).
3.11. X-ray crystallographic study
The single crystal of compound 4 suitable for X-ray diffraction
analysis was grown up from a hexane solution that contained a
small amount of methanol. The single crystal of complex 8 was
grown up from a dichloromethane solution. The single crystal of
compound 2a was grown up from THF-d8 (within the course of
its formation from 2, inside an NMR sample tube). X-ray data for
4 and 8 were collected on a Bruker SMART 6K diffractometer (graph-
ite-monochromatized Mo Ka radiation, 0.71073 Å) using x scan
mode at 120 K. X-ray data for 2a were collected on a Bruker SMART
APEX diffractometer (graphite-monochromatized Mo Ka radiation,
0.71073 Å) using x scan mode at 293 K. The crystal of 8 exhibited
twin behavior and the data for it was treated using GEMINI software
[51]. In all cases, the absorption corrections were performed semi-
4. Supplementary material
CCDC 667529, 667530 and 668555 contain the supplementary
crystallographic data for 4, 8, and 2a. These data can be obtained
free of charge from The Cambridge Crystallographic Data Centre
via www.ccdc.cam.ac.uk/data_request/cif.
Acknowledgements
The authors affiliated at the NWU of Xi’an are grateful to the
North-West University of Xi’an (Grant 05NW46) and the National
Science Foundation of the Shaanxi Province of the PR China (Grant
20051321) for the financial support. A.V.C. is grateful to the Royal
Society of Chemistry for the RSC Journal Grants for International
Authors. Authors are also thankful to Dr. Cheng Yaofeng (the Sang-
hai Institute of Organic Chemistry, Chinese Academy of Science,
Shanghai, PR China) for his kind help.
Table 4
Crystal and structure refinement data for 4 ꢁ CH3OH, 8 (dimer), and 2a (dimer, 1:1
adduct with THF-d8)
4
8
2a
Empirical formula
Formula weight
Color, habit
Crystal size (mm)
Crystal system
Space group
Cell dimensions
a (Å)
b (Å)
c (Å)
a (°)
b (°)
C
24H28N2O
C46H46Cl6N4Zr2
1050.01
Colorless block
C28H52Li4N8O2
560.54
Colorless block
360.48
Yellow block
0.20 ꢂ 0.15 ꢂ 0.15 0.15 ꢂ 0.03 ꢂ 0.02 0.41 ꢂ 0.35 ꢂ 0.21
References
Monoclinic
P21/c
Monoclinic
P21/n
Triclinic
ꢀ
P1
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16.8122(13)
9.1808(7)
12.9098(10)
90.00
94.489(2)
90.00
1986.5(3)
4
1.205
9.972(3)
9.520(3)
23.344(8)
90.00
99.625(8)
90.00
2184.9(13)
2
1.596
8.6775(10)
9.8895(11)
10.8199(13)
97.506(2)
90.229(2)
110.682(2)
859.98(17)
1
c (°)
Volume (Å3)
Z
Dcalc. (g cmꢀ3
)
1.082
Absorption
0.074
0.883
0.068
coefficient l
(mmꢀ1
F(000)
)
776
1064
304
h Range (°)
Index ranges
2.73 < h < 26.00
ꢀ20 6 h 6 20,
ꢀ10 6 k 6 11,
ꢀ8 6 l 6 15
9406
1.77 < h < 26.00
ꢀ10 6 h 6 10,
ꢀ11 6 k 6 11,
ꢀ28 6 l 6 28
3003
1.77 < h < 26.00
ꢀ8 6 h 6 10,
ꢀ12 6 k 6 11,
ꢀ12 6 l 6 13
4726
[14] M.A. Esteruelas, A.M. Lopez, A.C. Mateo, E. Onate, Organometallics 24 (2005)
5084.
Reflections
collected
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[23] G. Paolucci, G. Pojana, J. Zanon, V. Lucchini, E.V. Avtomonov, Organometallics
16 (1997) 5312.
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Independent
reflections (Rint
Reflections with
I > 2r(I)
Data/restraints/
parameters
3897 (0.0489)
2250
3050 (0.0000)
2154
3307 (0.0453)
1773
)
3897/0/256
3050/0/139
3307/0/271
R indices [I > 2r(I)]
R1 = 0.0932,
wR2 = 0.2012
R1 = 0.1627,
wR2 = 0.2233
ꢀ0.562/0.918
R1 = 0.0823,
wR2 = 0.1778
R1 = 0.1185,
wR2 = 0.1937
ꢀ0.528/0.538
R1 = 0.0574,
wR2 = 0.1346
R1 = 0.1011,
wR2 = 0.1525
ꢀ0.151/0.156
R indices (all data)
Largest difference
in hole/peak
(e Åꢀ3
)

2368
W. Nie et al. / Journal of Organometallic Chemistry 693 (2008) 2355–2368
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