Bridged dinuclear tripodal tris(amido)phosphane complexes of titanium and zirconium as diligating building blocks for organometallic polymers

Article abstract of DOI:10.1002/ejic.200701015

Appropriate bridging ligands allow for the preparation of bimetallic titanium and zirconium precursors to transition-metal-containing polymers using the formally trianionic P(CH₂NAr^R)₃ ligand (where Ar^R = Ph, and 3,5-Me₂C₆H₃ for a and b, respectively). Lithiation of the known amidophosphane ligand precursors P(CH₂NHAr^R)₃ (1a,b) with 3 equiv. of nBuLi cleanly provided the diethyl ether adducts P(CH₂NAr ^R)₃Li₃(OEt₂J_1.5 (2a,b). The THF adduct P(CH₂NPh)₃-Li₃(THF)₅ (2a-THF) was characterized by X-ray crystallography. Protonolysis reactions were used to prepare the mononuclear titanium complexes P(CH₂NAr ^R)₃TiOC₆H₄tBu (4a,b) and dinuclear species [P(CH₂NPh)₃TiNMe₂]₂-μ-4, 4′{O[3,3′,5,5′-(C₆H₂Me₂) ₂]O} (5a), [P(CH₂NPh)₃Ti]₂(μ-O) (6a), and P(CH₂N-3,5-Me₂C₆H₃) ₃Ti-μ-O-Ti(NMe₂)₃ (7b), from P(CH ₂NAr^R)₃TiNMe₂. The reactions of 1a,b with Zr(NEt₂)₄ afforded metal complexes of the type P(CH₂NAr^R)₃ZrNEt₂ (8a,b). The chloride complexes P(CH₂NAr^R)₃ZrCl(THF) (9a,b) were prepared by treatment of HNEt₃Cl with 1 or 2. The complexes 9a,b reacted with cyclopentadienyllithium (C₅H₅Li) to produce P(CH₂NAr^R)₃ZrCp (10a,b), which were also prepared by the reactions of the lithium salts 2a,b with CpZrCl₃. The dilithium salt of the fulvalene dianion (Li₂C₁₀H ₈) reacts with 9a,b to produce the dinuclear complexes trans-[P(CH₂NAr^R)₃Zr]₂(μ- η⁵:η⁵ -C₁₀H₈) (10a,b), respectively. The facile preparation of transition-metal-containing polymers from the bridged dinuclear complexes was illustrated by the reaction of 6a with half an equivalent of [Rh(CO)₂(μ-Cl)]₂, which precipitated polymeric Cl(CO)Rh[P(CH₂NPh)₃Ti] ₂(μ-O). Wiley-VCH Verlag GmbH & Co. KGaA, 2008.

Full text of DOI:10.1002/ejic.200701015

FULL PAPER
DOI: 10.1002/ejic.200701015
Bridged Dinuclear Tripodal Tris(amido)phosphane Complexes of Titanium and
Zirconium as Diligating Building Blocks for Organometallic Polymers
Hua Han[a] and Samuel A. Johnson*[a]
Keywords: Tripodal ligands / Phosphane ligands / Titanium / Zirconium / Polymers
Appropriate bridging ligands allow for the preparation of bi-
metallic titanium and zirconium precursors to transition-
metal-containing polymers using the formally trianionic
P(CH2NArR)3 ligand (where ArR = Ph, and 3,5-Me2C6H3 for
afforded metal complexes of the type P(CH2NArR)3ZrNEt2
(8a,b). The chloride complexes P(CH2NArR)3ZrCl(THF)
(9a,b) were prepared by treatment of HNEt3Cl with 1 or 2.
The complexes 9a,b reacted with cyclopentadienyllithium
a and b, respectively). Lithiation of the known amidophos- (C5H5Li) to produce P(CH2NArR)3ZrCp (10a,b), which were
phane ligand precursors P(CH2NHArR)3 (1a,b) with 3 equiv.
of nBuLi cleanly provided the diethyl ether adducts
P(CH2NArR)3Li3(OEt2)1.5 (2a,b). The THF adduct P(CH2NPh)3-
Li3(THF)5 (2a-THF) was characterized by X-ray crystallog-
raphy. Protonolysis reactions were used to prepare the
mononuclear titanium complexes P(CH2NArR)3TiOC6H4tBu
(4a,b) and dinuclear species [P(CH2NPh)3TiNMe2]2-µ-
4,4Ј{O[3,3Ј,5,5Ј-(C6H2Me2)2]O} (5a), [P(CH2NPh)3Ti]2(µ-O)
(6a), and P(CH2N-3,5-Me2C6H3)3Ti-µ-O-Ti(NMe2)3 (7b), from
P(CH2NArR)3TiNMe2. The reactions of 1a,b with Zr(NEt2)4
also prepared by the reactions of the lithium salts 2a,b with
CpZrCl3. The dilithium salt of the fulvalene dianion
(Li2C10H8) reacts with 9a,b to produce the dinuclear complexes
trans-[P(CH2NArR)3Zr]2(µ-η5:η5-C10H8) (10a,b), respectively.
The facile preparation of transition-metal-containing polymers
from the bridged dinuclear complexes was illustrated by the
reaction of 6a with half an equivalent of [Rh(CO)2(µ-Cl)]2, which
precipitated polymeric Cl(CO)Rh[P(CH2NPh)3Ti]2(µ-O).
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2008)
eter of this phosphane ligand,[12,18] and allows for the ob-
servation of through-space spin-spin coupling by NMR
spectroscopy when the central metal is spin-active,[19] and in
paramagnetic complexes provides an electronic exchange-
coupling pathway when a second paramagnetic metal center
is bound to the phosphane donor.[19] With suitable building
blocks, this interaction could be used to create hetero-
metallic[20,21] 1D wires, or 2D or 3D networks that could
have properties resulting from through-space exchange-
coupling, or through-space electron-transfer. The target bis-
(phosphane) building blocks for such an approach are
shown in Scheme 1, and feature a pair of metal-bearing
tripodal tris(amido)phosphane ligands, as well as a bridge
between the metal centers labeled M. The addition of suit-
able late-transition-metal fragments capable of bonding to
two phosphane moieties, labeled MЈLn in Scheme 1, should
provide a facile route to transition-metal-containing oligo-
mers and polymers. Although there are a plethora of exam-
ples of bis(phosphanes) used as bridging ligands,[22–24] as
well as flexible ligands incorporating hard and soft donors
that have been utilized as building blocks for bimetallic and
polynuclear early-late transition-metal clusters,[25,26] the
complexes we propose here could provide rare examples of
linear bis(phosphane) building blocks,[27–32] where through-
space interactions provide the potential for extended inter-
actions. In this paper, we test the synthetic feasibility of
Introduction
New methods to incorporate metal complexes into poly-
mers or extended 2D and 3D structures are of current inter-
est due to the additional physical properties, such as mag-
netism and redox chemistry, that the incorporation of these
metal centers permits. A variety of methods have been used
to incorporate metal centers in polymers or extended supra-
molecular networks,[1–3] which include the use of divergent
diligating[4–10] donors incapable of coordinating to a single
metal center.
Recently, we reported the synthesis and initial study of
the tripodal amido phosphane ligands of the type
[11–13]
P(CH2NHArR)3
where ArR is an aryl substituent.
With metals in oxidation states greater than +3, these li-
gands preferentially form complexes where all three amido
donors chelate to the metal, similar to other tripodal amido
ligands.[14–16] Although the lone-pair of the phosphane do-
nor is aimed away from the amido-chelated metal center,
the minor lobe of this hybridized lone-pair orbital extends
back towards the metal center. This through-space interac-
tion[17] has been shown to influence the electronic param-
[a] Department of Chemistry & Biochemistry, University of Windsor,
Windsor, ON, Canada, N9B 3P4
E-mail: sjohnson@uwindsor.ca
Fax: +1-519-973-7098
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H. Han, S. A. Johnson
FULL PAPER
preparing such building blocks using the diamagnetic early
The solid-state molecular structure of 2a-THF was deter-
transition metals zirconium and titanium, with the goal of mined by X-ray crystallography and is shown in Figure 1.
introducing redox active and paramagnetic metal-bridge The complex has an approximate mirror plane of symmetry,
fragments in future endeavours.
with the central Li ion, Li(3), chelated by all three amido
donors and bearing a single THF donor. The two remain-
ing Li ions bridge between amido donors, and adopt four-
coordinate geometries by bonding to two THF moieties
apiece. Lithium salts of tripodal amido donors are known
to adopt a multitude of bonding motifs in the solid state,[33]
and structurally related tripodal amido lithium salts are
known.[34]
Scheme 1.
Results and Discussion
The reaction of lithium salts of amido donors with tran-
sition-metal chlorides is a typical route to transition-metal
ancillary ligand complexes, and thus the lithium salts of
P(CH2NHArR)3 (1a,b) were sought after as useful precur-
sors (where the aromatic substituents, ArR = Ph and 3,5-
Me2C6H3 are denoted as a and b, respectively). The lithium
salt of the phenyl-substituent-bearing ligands were easily
obtained by the reaction of a slurry of P(CH2NHPh)3 in
diethyl ether with 3 equiv. of nBuLi, as shown in Scheme 2.
Figure 1. Solid-state molecular structure of 2a-THF as determined
by X-ray crystallography. Ellipsoids are shown at the 33% prob-
ability level. Hydrogen atoms are omitted and only the oxygen
atoms associated with the THF donors are shown for clarity. Se-
After the addition of 2 equiv. of nBuLi the solids dissolved, lected distances [Å]: Li(1)–N(2) 2.069(7), Li(1)–N(1) 2.189(8),
and the addition of the 3rd equiv. resulted in the precipi-
tation of the analytically pure product, P(CH2NPh)3Li3-
Li(2)–N(1) 2.150(9), Li(2)–N(3) 2.053(7), Li(3)–N(3) 2.063(7),
Li(3)–N(2) 2.088(7), Li(3)–N(1) 2.149(7), Li(3)–P(1) 3.074(6). Se-
lected bond angles (°): C(2)–P(1)–C(1) 104.38(18), C(2)–P(1)–C(3)
(OEt2)1.5 (2a). The lithium salt P(CH2N-3,5-Me2C6H3)3Li3-
101.5(2), C(1)–P(1)–C(3) 107.84(19).
(OEt2)1.5 (2b) was prepared in an analogous manner from
1b. The complexes 2a and 2b are insoluble in toluene, di-
The room temperature 1H, 7Li, and 13C{1H} NMR spec-
ethyl ether and dichloromethane, but soluble in THF. The
tra of both 2a and 2b are consistent with high symmetry
dissolution of THF results in the displacement of the di-
ethyl ether donors as demonstrated by the crystallization of
P(CH2NPh)3Li3(THF)5 (2a-THF) by cooling a THF solu-
tion of 2a. This THF adduct is soluble in cold CH2Cl2, but
lithium environment. The fluxional nature of Li salts of re-
decomposes over the course of 1 h at room temperature in
lated species is well documented.[34] The 31P{1H} NMR
this solvent.
1
species. The H NMR spectrum of 2a in [D8]THF consists
of a single PCH2 resonance and a set of three aromatic
resonances, and the Li NMR spectrum displays a single
7
spectrum of 2a and 2b in [D8]THF display singlets at δ =
–22.2 and –21.7 ppm, respectively, which are only slightly
altered from the δ = –32.1 and –29.6 ppm chemical shifts
observed for 1a and 1b. The change of shift is in the oppo-
site direction we have previously observed for early transi-
tion-metal complexes of these ligands, which exhibit 31P
chemical shifts as low as –108.5 ppm.[12]
Synthesis and Characterization of Titanium Complexes
A variety of synthetic approaches to P(CH2NArR)3TiCl
were attempted, due to the fact that it could serve as a
potential precursor to a variety of bridged dinuclear com-
plexes via salt metathesis. Unfortunately, the direct reaction
of the lithium salts 2a,b with TiCl4 produced a mixture
of products. The reaction of the ligand precursors
Scheme 2.
472
P(CH2NHArR)3 with stoichiometric quantities of (Me2N)3-
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Titanium and Zirconium Complexes for Organometallic Polymers
TiCl also failed to produce the desired product, and the metal center affects the properties of the phosphane donor,
[12]
previously characterized P(CH2NArR)3TiNMe2
and un- despite the fact that the phosphane lone-pair is not coordi-
reacted P(CH2NHArR)3 were identified as two of the major nated to the metal center.[12]
components of the reaction mixture in each case. Similarly,
the reaction of P(CH2NArR)3TiNMe2 with either the am-
monium salt HNEt3Cl, or Me3SiCl, failed to yield the
desired chloride complex.
Due to the difficulty in accessing the chloride complex,
we attempted to demonstrate that the amido complexes,
P(CH2NArR)3TiNMe2 (3a,b), could act as precursors to
bridged complexes through protonolysis reactions. To test
this hypothesis we prepared the mononuclear complexes
P(CH2NArR)3TiOC6H4tBu (4a,b) by the reaction of 1,4-
HOC6H4tBu with P(CH2NArR)3TiNMe2 in toluene, as
shown in Equation (1). The reactions are slow at room tem-
perature, and required 48 h to go to completion. The result-
ant products are thermally stable dark-red solids.
Figure 2. Solid-state molecular structure of 4b as determined by X-
ray crystallography. Ellipsoids are shown at the 50% probability
level. Hydrogen atoms are omitted for clarity. Selected distances
[Å]: Ti(1)···P(1) 3.0150(16), Ti(1)–N(1) 1.918(4), Ti(1)–N(2)
1.926(4), Ti(1)–N(3) 1.918(4), Ti(1)–O(1) 1.784(3), O(1)–C(28)
1.369(5), P(1)–C(1) 1.854(5), P(1)–C(2) 1.861(5), P(1)–C(3)
1.863(5). Selected bond angles: O(1)–Ti(1)–P(1) 178.20(12), Ti(1)–
O(1)–C(28) 160.20(3), C(1)–P(1)–C(2) 102.8(2), C(1)–P(1)–C(3)
102.8(2), C(2)–P(1)–C(3) 102.8(2), N(1)–Ti(1)–O(1) 112.66(16),
N(2)–Ti(1)–O(1) 115.74(16), N(3)–Ti(1)–O(1) 113.82(16), N(1)–
Ti(1)–N(3) 105.73(17), N(2)–Ti(1)–N(3) 104.02(16), N(2)–Ti(1)–
N(1) 103.77(16).
Aryloxy ligands have been utilized in the past as bridging
ligands to generate binuclear or larger complexes with
cyclopentadienyl-substituted titanium and zirconium
complexes.[35,37,38] The reaction of 4,4Ј-HO[3,3Ј,5,5Ј-
(C6H2Me2)2]OH with 2 equiv. P(CH2NPh)3TiNMe2 (3a)
in toluene is slow at room temperature, and after 48 h gave
the binuclear compound [P(CH2NPh)3Ti]2{µ-O[3,3Ј,5,5Ј-
(Me2C6H2)2]O-} (5a) as a red solid in 85% yield, as shown
in Equation (2). Compound 5a is soluble in aromatic hydro-
Crystalline 4b was obtained by slow evaporation of a
pentane solution, and the solid-state molecular structure
was determined by X-ray crystallography. The unit cells
contain two crystallographically distinct molecules of 4b in
the asymmetric unit, and an ORTEP depiction of one of
these is shown in Figure 2. The four-coordinate structure is
a distorted tetrahedron, with the phosphane lone pair for-
mally directed away from the titanium center. The Ti(1)–
O(1)–C(28) bond angle of 160.20(3)° is distorted signifi-
cantly from linearity, but this angle and the Ti–O distance
of 1.784(3) Å are typical.[35] The Ti–N bonds of 4b
[1.918(4), 1.918(4), 1.926(4) Å] are shorter than those of
P(CH2N-3,5-Me2C6H3)TiNMe2 (3b) [1.963(7), 1.941(6),
1.934(6) Å], reflecting the slightly stronger σ-bonding and
π-donation from these donors in compound 4b.[36] The
13C{1H} NMR chemical shift of the ipso carbon atoms
bonded directly to the oxygen atoms are at δ = 164.2 and
153.3 ppm, for 4a and 4b, respectively, which reflects how
strongly the degree of π-donation from the oxygen donor
in these complexes is influenced by the amido donor sub-
stituents.[35] The sum of C–P–C bond angles and P···Ti dis-
tances in the solid-state structure of complex 4b are similar
to those observed in the parent compound P(CH2N-3,5-
Me2C6H3)3TiNMe2 (3b); however, the 31P{1H} NMR
chemical shifts in 4a,b of δ = –81.1 and –77.9 ppm, respec-
tively, are significantly different than those of 3a,b, which
are δ = –65.6 and –61.6 ppm. This corroborates our pre-
vious observation that the electron density at the chelated
1
carbons such as toluene and benzene. The H NMR and
13C{1H} NMR spectra of compound 5a show the disap-
pearance of –NMe2 ligand and equivalence of the two Ti
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473

H. Han, S. A. Johnson
FULL PAPER
metal fragments, as well as one set of aromatic resonances. angles and lengths corroborate this hypothesis. For exam-
In the 1H NMR spectrum, the aromatic protons of the ple, the Ti(1)···P(1) separation of 3.051(2) Å is the longest
{µ-O[3,3Ј,5,5Ј-(C6H2Me2)2]O-}2– ligand are equivalent and we have observed in Ti complexes of these ancillary ligands.
appear as a singlet at δ = 7.17 ppm. The 31P{1H} NMR
spectrum displays a singlet at δ = –78.6, which is compar-
able to that of P(CH2NPh)3TiOC6H4tBu (4a) at δ =
–81.1 ppm. Unfortunately, the analogous complex 5b could
not be prepared by this method, and attempts to prepare
crystals of 5a suitable for study by X-ray diffraction only
generated a microcrystalline solid.
Single atom oxo-bridges are also accessible, though not by
direct reaction with H2O.[39] The reaction of P(CH2NPh)3-
TiNMe2 (3a) with 1/2 an equivalent of H2O results in an
insoluble colorless precipitate that likely consists largely of
TiO2. However, the slow addition of a stoichiometric
amount of water by using the hydrated salt Na2SO4·10H2O
resulted in the formation of the oxo-bridged binuclear com-
pound [P(CH2NPh)3Ti]2(µ-O) (6a), as shown in Equation (3).
Figure 3. Solid-state molecular structure of 6a as determined by X-
ray crystallography. Ellipsoids are shown at the 50% probability
level. Hydrogen atoms are omitted for clarity. Selected distances
[Å]: Ti(1)···P(1) 3.051(2), Ti(1)–N(1) 1.907(2), Ti(1)–O(1) 1.802(8),
C(1)–P(1) 1.855(3), C(1)–N(1) 1.467(4), C(2)–N(1) 1.397(3), Se-
lected bond angles: P(1)–Ti(1)–O(1)–Ti(2) 180.00(0), N(1)–Ti(1)–
O(1) 115.46(7), N(1)–C(1)–P(2) 115.53(2), C(1)–N(1)–C(2)
118.29(2),
C(2)–N(1)–Ti(1)
129.96(18),
C(1)–N(1)–Ti(1)
110.61(18), C(1)–P(1)–C(1) 102.05(11).
Attempts to make an analogous bridging oxo complex
with P(CH2N-3,5-Me2C6H3)3TiNMe2 (3b) have failed,
possibly due to the steric bulk afforded by the aromatic
methyl substituents; however, it may be that kinetic factors
prevent its facile preparation. In an attempt to find an alter-
nate route to these complexes, compound 3b was treated
with 1 equiv. of H2O and excess Ti(NMe2)4 at room tem-
perature to yield the binuclear titanium complex P(CH2N-
3,5-Me2C6H3)3Ti-µ-O–Ti(NMe2)3 (7b), as shown in Equa-
tion (4). Crystals suitable for an X-ray structure analysis
The bridging oxo formulation was confirmed by X-ray
crystallography, and an ORTEP depiction of the solid-state
molecular structure is shown in Figure 3. Complex 6a crys-
tallizes from toluene to give crystals belonging to the trigo-
nal space group and possessing the crystallographically im-
posed S6 symmetry. A second monoclinic pseudopoly-
morph containing cocrystallized toluene was also charac-
terized; however, no significant structural differences were
observed. The molecule has a strictly linear P–Ti–O–Ti–P
1
unit, which defines the S6 axis. As expected, the H NMR
spectrum of 6a contains only the PCH2 and three aromatic
resonances associated with the ancillary ligand. The
31P{1H} NMR shift of –39.3 ppm is unusual, compared to
the chemical shift of 4a and 5a, which are more negative by
almost 40 ppm. A reasonable rationale for this shift might
be that the steric interaction between the two ancillary li-
gand moieties in 6a result in a strained ligand conformation
with larger N–Ti–O angles and P–Ti distances. The bond
474
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Titanium and Zirconium Complexes for Organometallic Polymers
were grown by slow evaporation of a toluene solution at duced the mononuclear zirconium complexes P(CH2NArR)3-
–30 °C. Unfortunately, attempts to react 7b with ZrNEt2 (8a,b) with the concomitant elimination of 3 equiv.
P(CH2NH-3,5-Me2C6H3)3 failed to produce the desired of HNEt2, as shown in Scheme 3.
product, [P(CH2N-3,5-Me2C6H3)3Ti]2(µ-O).
Figure 4 shows the solid-state molecular structure of 7b,
as well as the selected bond lengths and bond angles. The
binuclear compound of 7b crystallizes in the rhombohedral
space group R-3, and the molecular structure has crystallo-
graphically imposed C3 symmetry. Both titanium atoms are
connected by a linear µ-oxo bridge, and the Ti(1)–O(1)
bond length of 1.757(3) Å is shorter than Ti(2)–O(1) bond
length of 1.886(3) Å. This is likely due to significantly
greater π-donation by the O-donor to Ti(1).[40] The aro-
matic substituents render the ancillary ligand amido donors
less potent than the -NMe2 groups, but also the hindered
rotation of the chelating amido donors prevents optimal
overlap of these orbitals with the available d orbitals on
Ti(1). The Ti(1)···P(1) distance of 2.968(14) Å is just slightly
shorter than observed for 3b or 4b, 3.015(5) and
3.015(16) Å, respectively. Also noteworthy is the 31P{1H}
NMR shift of δ = –62.9, which is significantly different than
the shift of –39.4 observed for 6a.
Scheme 3.
These reactions require 24–48 h to go to completion and
1
no intermediates were observed by H or 31P{1H} NMR
spectroscopy. The resultant products are all obtained in
69–86% yields as thermally stable yellow solids. The room-
temperature 1H NMR spectra ([D6]benzene) of P(CH2NArR)3-
ZrNEt2 (8a,b) correspond to apparent threefold symmetric
complexes in solution, similar to the structurally charac-
terized P(CH2NArR)3TiNMe2 (3a,b). The monomeric for-
mulations of the solution structures were verified by meas-
uring the diffusion rates of P(CH2NArR)3ZrNEt2 (8a,b) by
diffusion-ordered NMR spectroscopy (DOSY NMR). The
rates proved to be nearly identical to the complexes 3a and
3b.
The 31P{1H} chemical shifts are δ = –75.2 and –70.8 ppm
for 8a,b, respectively. These values are significantly more
negative than those of the Ti analogues, and opposite to
ray crystallography. Ellipsoids are shown at the 50% probability
Figure 4. Solid-state molecular structure of 7b as determined by X-
the expected shift due to the increase of C–P–C angles that
results from the ligand straining to accommodate a much
larger Zr metal center. These shifts provide additional evi-
dence that an electrostatic through-space interaction
strongly affects the phosphane moiety in these com-
plexes.[12]
level. Hydrogen atoms are omitted for clarity. Selected distances
[Å]: Ti(1)···P(1) 2.968(14), Ti(1)–N(1) 1.935(2), Ti(1)–O(1) 1.757(3),
Ti(2)···P(1) 6.612, Ti(2)–N(2) 1.881(2), Ti(2)–O(1) 1.886(3), C(1)–
P(1) 1.850(3), C(1)–N(1) 1.461(3), Selected bond angles: Ti(1)–
O(1)–Ti(2) 180.0, N(1)–Ti(1)–N(1) 106.15(7), N(1)–Ti(1)–O(1)
112.62(6), N(2)–Ti(2)–N(2) 105.13(8), N(2)–Ti(2)–O(1) 113.52(7),
C(1)–P(1)–C(1) 103.65(10), C(1)–N(1)–C(2) 115.74(2), C(1)–N(1)–
Ti(1) 108.01(16), C(2)–N(1)–Ti(1) 135.87(16), C(10)–N(2)–C(11)
The zirconium chloride complexes P(CH2NArR)3-
ZrCl(THF) (9a,b) were readily prepared by reaction of
P(CH2NArR)3ZrNEt2 (8a,b) with HNEt3Cl, and isolated in
84.1–89.6% yields as yellow solids. The reaction was carried
out in toluene at room temperature. After 1 h, THF was
added just before the solvent was removed. If the solvent
was removed without first adding THF, the product decom-
112.45(2),
C(10)–N(2)–Ti(2)
129.37(2),
C(11)–N(2)–Ti(2)
117.99(18).
Synthesis and Characterization of Zirconium Complexes
Similar to the Ti complexes, attempts to react posed. The chloride complex formed in the absence of THF
ZrCl4(THF)2 with the lithium salts 2a,b under a variety of is likely stabilized by HNEt2, which is removed under
reaction conditions produced only trace amounts of the vacuum. When the reaction of P(CH2NArR)3ZrNEt2 (8a,b)
complex P(CH2NArR)3ZrCl(THF), identifiable in the with HNEt3Cl was performed using THF as the solvent, it
31P{1H} NMR due to its later preparation by an alternate took more than 48 h to go to completion and a plethora of
route (vide infra). The reaction of phosphane ligands long-lived intermediates were observed by 31P{1H} NMR
[12]
P(CH2NHArR)3
with 1 equiv. Zr(NEt2)4 cleanly pro- spectroscopy. This probably indicates that the amido do-
Eur. J. Inorg. Chem. 2008, 471–482
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475

H. Han, S. A. Johnson
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nors of the tridentate ligands are protonated as easily as cyclopentadienyl ligand in the coordination pocket of the
diethylamido ligand, and the THF solvent molecules can trisamido-chelated P(CH2NArR)3Zr fragment. The sum of
then coordinate to the zirconium metal center and block C–P–C angles in 316.0(2)° is larger than observed in any of
proton-transfer pathways, thus rendering the formation of the titanium complexes, consistent with the strain on the
the thermodynamic products slow.
ancillary ligand to accommodate a large metal such as Zr.
The 31P{1H} NMR chemical shifts for P(CH2NArR)3- The Zr(1)···P(1) separation of 3.0523(6) Å is only slightly
ZrCl(THF) (9a,b) are δ = –71.5 and –66.0 ppm, respectively. longer than typical Zr–P bond lengths, which reside be-
The room-temperature 1H NMR spectra are consistent with tween 2.7–2.9 Å, and is nearly identical to the longest re-
the presence of 1 equiv. coordinated THF. Despite apparent ported Zr–P bond length of 3.033 Å, which was observed
five-coordinate geometries, 9a,b both exhibit 1H and in an organometallic PMe3 adduct.[41]
13C{1H} NMR spectra that are consistent with threefold
pseudosymmetry in solution. Attempts to gain insight into
the nature of the fluxional process required for such appar-
1
ent symmetry were made by monitoring the H spectra of
[D8]toluene solutions of 9a,b down to –80 °C, but no broad-
ening or decoalescence of resonances were observed. The
diffusion rates of the complexes P(CH2NArR)3ZrNEt2
(8a,b) and 9a,b, were obtained by diffusion-ordered NMR
spectra (DOSY NMR) and were found to be nearly iden-
tical; although it is notable that the resonances associated
with the coordinated THF moieties of 9a,b diffused at a
slightly faster rate, indicative of rapid dissociation and asso-
ciation in solution. Consistent with this observation, the ad-
dition of THF to C6D6 solutions of 9a,b resulted in a pair
of shifted resonances, rather than unique pairs of reso-
nances for coordinated and free THF molecules.
Figure 5. Solid-state molecular structure of 10b as determined by
X-ray crystallography. Ellipsoids are shown at the 50% probability
level. Hydrogen atoms are omitted for clarity. Selected distances
[Å]: Zr(1)···P(1) 3.0523(6), Zr(1)–N(1) 2.0536(18), Zr(1)–N(2)
2.0624(17), Zr(1)–N(3) 2.0986(17), Zr(1)–C(28) 2.5290(19), Zr(1)–
C(29) 2.553(2), Zr(1)–C(30) 2.541(2), Zr(1)–C(31) 2.518(2), Zr(1)–
C(32) 2.498(2), P(1)–C(1) 1.850(2), P(1)–C(2) 1.846(2), P(1)–C(3)
1.857(2). Selected bond angles: C(1)–P(1)–C(2) 104.93(12), C(1)–
P(1)–C(3) 106.40(12), C(2)–P(1)–C(3) 104.66(11), Zr(1)–N(1)–C(1)
Attempts to make the hydride, methyl, or benzyl-substi-
tuted complexes from the reaction of the zirconium chloride
precursor 9a,b with NaH, MeLi, or BrMgCH2Ph all failed.
The latter complex could also not be prepared by the reac-
tion of the P(CH2NHArR)3 ligand precursors with
Zr(CH2Ph)4. Similarly, attempts to make aryloxy species
similar to those prepared with the titanium complexes
failed, either by protonolysis reactions using 8a,b, or salt
107.31(13),
Zr(1)–N(1)–C(4)
139.05(14),
Zr(1)–N(2)–C(2)
109.55(13), Zr(1)–N(2)–C(12) 137.95(14), Zr(1)–N(3)–C(3)
105.76(13),
Zr(1)–N(3)–C(20)
P(1)–C(2)–N(2)
C(1)–N(1)–C(4)
C(3)–N(3)–C(20)
140.52(14),
118.48(15),
113.62(17),
113.60(17),
P(1)–C(1)–N(1)
P(1)–C(3)–N(3),
C(2)–N(2)–C(12)
N(1)–Zr(1)–N(2)
metathesis reactions using 9a,b. It appears that these rela- 120.31(16),
121.69(16),
112.46(16),
tively coordinatively unsaturated complexes are too un-
stable to isolate; however, the reaction of P(CH2NArR)3-
104.91(7), N(1)–Zr(1)–N(3) 99.37(7), N(2)–Zr(1)–N(3) 106.38(7).
ZrCl(THF) with CpLi (where Cp = C5H5) produced the
cyclopentadienyl complex P(CH2NArR)3ZrCp, as shown in
Scheme 4. The reaction of the lithium salts 2a,b with
CpZrCl3 provides an alternate route to these complexes.
The stability of the cyclopentadienyl zirconium com-
plexes 10a,b suggests that the most versatile dinuclear zirco-
nium building blocks should bear polyhapto ligands. The
fulvalene dianion (C10H8)2– has been used as a bridging
ligand to promote intermetal communication,[42–47] and its
obvious relation to the Cp ligand suggested that these com-
plexes should be stable and isolable. The reactions of
2 equiv. of P(CH2NArR)3ZrCl(THF) (9a,b) with 1 equiv. of
[48]
(C10H8)Li2
at room temperature provided the binuclear
zirconium complexes trans-[P(CH2NArR)3Zr]2(η5:η5-C10H8)
(11a,b), as shown in Equation (5). These hydrocarbon-solu-
ble complexes were purified by slow evaporation of satu-
rated benzene/hexamethyldisiloxane solutions, which pro-
vided yellow crystalline solids.
Scheme 4.
The structure of compound 11b was confirmed by X-
X-ray-quality single crystals of 10b were obtained from ray diffraction and an ORTEP depiction of the solid-state
the slow evaporation of a saturated toluene solution, and molecular structure is shown in Figure 6, together with se-
the solid-state molecular structure is depicted in Figure 5. lected bond lengths. The molecule crystallizes with a center
As anticipated, the structure reveals an η5-coordinated of symmetry; the two metal centers are crystallographically
476
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Titanium and Zirconium Complexes for Organometallic Polymers
this complex. A significant change of the 31P NMR chemi-
cal shift to lower field is observed for complexes 11a (δ =
–57.1 ppm) and 11b (δ = –56.3 ppm), compared to their
corresponding mononuclear zirconium complexes 10a (δ =
–67.5 ppm) and 10b (δ = –66.9 ppm).
Polymer Synthesis
The bridged binuclear complexes we have prepared
should provide a facile route to polymeric materials that
contain transition metals along the main polymer chain.
The synthetic viability of this approach can be demon-
strated using complex 6a. We have previously shown
that two equivalents of the mononuclear complexes
P(CH2NArR)TiNMe2 (3a,b) react cleanly with [Rh(CO)2-
(µ-Cl)]2 to generate the heterobimetallic complexes trans-
Cl(CO)Rh[P(CH2NArR)3TiNMe2]2.[12] An analogous reac-
tion with one equivalent of the dinuclear oxo-bridged tita-
nium complex 6a precipitated a red insoluble polymer that
analyses as Cl(CO)Rh[P(CH2NPh)3Ti]2O, as shown in
Equation (6). A single CO stretch is observed in the IR
spectrum of a KBr pellet of 12a at 1975.2 cm–1. Further
work in the preparation of a series of polymers and their
complete characterization is currently underway.
equivalent and are coordinated to the bridging fulvalenide
1
ligand in a trans manner.[49] Both H and 31P{1H} NMR
spectroscopy support the presence of only the trans isomer;
the 31P{1H} NMR spectra of complexes 11a and 11b exhi-
bit one signal each at δ = –57.1 and –56.3, respectively. The
central fulvalene C–C bond length of 1.471(6) Å is within
the normal range found in fulvalene metal complexes with a
degree of multiple bonding between the rings.[50] The bond
lengths and angles of the binuclear compound 11b are sim-
ilar to those of the analogous mononuclear compound 10b.
The P···Zr distance of 3.0698(9) Å for 11b is slightly larger
than that of 3.0523(6) Å for 10b.
Figure 6. Solid-state molecular structure of 11b as determined by
X-ray crystallography. Ellipsoids are shown at the 50% probability
level. Hydrogen atoms and 3,5-methyl substituents are omitted for
clarity. Selected distances [Å]: P(1)–Zr(1) 3.0698(9), C(28)–Zr(1)
2.620(3), C(29)–Zr(1) 2.544(3), C(30)–Zr(1) 2.487(3), C(31)–Zr(1)
2.488(3), C(32)–Zr(1) 2.539(3),C(28)-(C28) 1.471(6), C(28)–C(29)
1.414(4), C(29)–C(30) 1.408(4), C(30)–C(31) 1.410(4), C(31)–C(32)
1.407(4), C(28)–C(32) 1.418(4), N(1)–Zr(1) 2.052(2), N(2)–Zr(1)
2.093(3), N(3)–Zr(1) 2.073(3).
Conclusions
The design of divergent metal-containing building blocks
provides a facile route to linear rigid metal-containing poly-
mers. With the smaller metal Ti it proved possible to gener-
ate bridges with η1-bound ligands, whereas with the larger
metal Zr attempts to generate bridged complexes only suc-
In the 1H NMR spectra of trans-[P(CH2NArR)3Zr]2- ceeded by utilizing polyhapto ligands. Our future goals in-
(η5:η5-C10H8) (11a,b), the fulvalene protons consist of a clude the inclusion of redox active or paramagnetic metal–
pair of resonances that appear to be triplets for this ligand fragments in lieu of Ti and Zr in the bisphosphane
AAЈBBЈ spin system, consistent with the high symmetry of moiety, as well as an in-depth investigation into the proper-
Eur. J. Inorg. Chem. 2008, 471–482
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477

H. Han, S. A. Johnson
FULL PAPER
ethyl ether (50 mL) at 0 °C and stirred at room temperature for 1 h.
The resultant solid was filtered and dried under vacuum (2.12 g,
75%). 1H NMR ([D8]THF, 500.1 MHz, 298 K): δ = 1.11 (t, 3J =
6.9 Hz, 9 H, OCH2CH3), 2.08 (s, 18 H, ArCH3), 3.38 (m, 3J =
7.0 Hz, 6 H, OCH2CH3 & PCH2), 5.80 (s, 3 H, p-H), 6.10 (s, 6 H,
o-H) ppm. 31P{1H} NMR ([D8]THF, 202.5 MHz, 298 K): δ = –21.7
(s) ppm. 13C{1H} NMR ([D8]THF, 125.8 MHz, 298 K): δ = 15.6
(s, OCH2CH3), 22.1 (s, PhCH3), 50.1 (d, JPC = 11 Hz, PCH2), 66.3
(s, OCH2CH3), 112.0, 112.8, 137.3 (s, o,m,p-Ph), 164.2 (m, ipso-C)
ties and characteristics of these polymers and the use of
these building blocks in the assembly of higher-dimensional
networks with functional physical properties.
Experimental Section
General Procedures: Unless otherwise stated, all manipulations
were performed under an inert atmosphere of nitrogen using either
standard Schlenk techniques or an M. Braun glove box. Dry, oxy-
gen-free solvents were employed throughout. Anhydrous pentane,
toluene, diethyl ether and THF were purchased from Aldrich,
sparged with dinitrogen, and passed through activated alumina un-
der a positive pressure of nitrogen gas; toluene and hexanes were
further deoxygenated using Ridox catalyst columns.[51] Deuterated
benzene, toluene, and THF were dried by heating at reflux with
sodium/potassium alloy, sodium, and potassium, respectively, in a
sealed vessel under partial pressure, then trap-to-trap distilled, and
freeze-pump-thaw degassed three times. Deuterated dichlorometh-
ane was heated in a sealed vessel over CaH2, then trap-to-trap dis-
tilled, and freeze-pump-thaw degassed three times. NMR spectra
were recorded on Bruker AMX (300 MHz) or Bruker AMX
(500 MHz) spectrometer. All chemical shifts are reported in ppm,
and all coupling constants are in Hz. For 19F{1H} NMR spectra,
trifluoroacetic acid was used as the external reference at δ =
0.00 ppm. 1H NMR spectra were referenced to residual protons
(C6D5H, δ = 7.15; C7D7H, δ = 2.09 ppm) with respect to tetrameth-
ylsilane at δ = 0.00 ppm. 31P{1H} NMR spectra were referenced to
external 85% H3PO4 at δ = 0.0. 13C{1H} spectra were referenced
relative to solvent resonances (C6D6, δ = 128.0; C7D8, δ =
20.4 ppm). Elemental analyses were performed by the Centre for
Catalysis and Materials Research (CCMR), Windsor, Ontario,
Canada. The compounds TiCl4, ZrCl4(THF)2, HO-(4-tBuC6H3),
4,4Ј-HO[3,3Ј,5,5Ј-(Me2C6H2)2]OH, HNEt3Cl, (C5H5)Li, CpZrCl3,
[(CO)2Rh(µ-Cl)]2, and 1.6  nBuLi in hexanes were purchased from
Aldrich, and used as received. The compounds 1a–b,[12] 3a–b,[12]
Ti(NMe2)3Cl,[52] Zr(NEt2)4,[53] and (C10H8)Li2,[48] were prepared by
published procedures.
7
ppm. Li NMR ([D8]THF, 116.7 MHz, 298 K): δ = 1.06 (s) ppm.
C33H48Li3N3O1.5P (562.55): calcd. C 70.46, H 8.60, N 7.47; found
C 70.70, H 8.78, N 7.36.
P(CH2NPh)3TiO-4-tBuC6H3 (4a): HO(4-tBuC6H3) (150 mg,
1.0 mmol) were added to a solution of P(CH2NPh)3TiNMe2 (3a),
(438.3 mg, 1.0 mmol) in 50 mL of toluene. The solution was stirred
for 48 h. The solvent was removed under vacuum and the remain-
ing red solid was rinsed with a small portion of cold pentane, and
then dried under vacuum (277 mg, 51%). 1H NMR (C6D6,
2
300 MHz, 298 K): δ = 1.19 [s, 9 H, C(CH3)3], 3.85 (d, JPH
=
7.0 Hz, 6 H, PCH2), 6.81 (m, 3 H, Ph p-H), 7.04 (m, 2 H, C6H4),
7.06 (m, 6 H, Ph m-H), 7.13 (m, 2 H, C6H4), 7.18 (m, 6 H, Ph o-
H) ppm. 13C{1H} NMR (C6D6, 125.8 MHz, 298 K): δ = 1.35 [s,
C(CH3)3], 31.7 [s, C(CH3)3], 44.1 (d, JPC = 20.0 Hz, PCH2), 116.4,
119.8, 121.1, 127.0, 129.8, 146.5, and 153.3 (s, C6H5, C6H4), 164.2
(s, ipso-C) ppm. 31P{1H} NMR (C6D6, 202.5 MHz, 298 K): δ =
–81.1 (s) ppm. C31H34N3OPTi (543.46): calcd. C 68.51, H 6.31, N
7.73; found C 68.92, H 6.85, N 7.27.
P(CH2N-3,5-Me2C6H3)3TiOC6H3-4-tBu (4b): HOC6H3-4-tBu
(150 mg, 1.0 mmol) were added to a solution of P(CH2N-3,5-
Me2C6H3)3TiNMe2 (3b), (522.3 mg, 1.0 mmol) in 50 mL of toluene.
The solution was stirred for 48 h. The solvent was removed under
vacuum and the remaining red solid was rinsed with a small por-
tion of cold pentane, and then dried under vacuum (378 mg, 60%).
X-ray quality crystals were obtained from toluene by slow evapora-
1
tion. H NMR (C6D6, 300 MHz, 298 K): δ = 0.29 [s, 9 H, C(CH3)
3], 1.90 (s, 18 H, ArCH3), 3.97 (d, 2JPH = 6.8 Hz, 6 H, PCH2), 6.23
(m, 2 H, C6H4), 6.25 (s, 3 H, Ph p-H), 6.45 (m, 2 H, C6H4), 6.59
(s, 6 H, Ph o-H) ppm. 13C{1H} NMR (C6D6, 125.8 MHz, 298 K):
δ = 1.7 [s, C(CH3)3], 21.3 (s, ArCH3), 21.9 [s, C(CH3)3], 45.3 (d,
JPC = 18.4 Hz, PCH2), 112.0, 114.2, 116.0, 116.5, 120.8, 123.5, and
138.6 (s, C6H5, C6H4), 153.3 (s, ipso-C) ppm. 31P{1H} NMR (C6D6,
202.5 MHz, 298 K): δ = –77.9 (s) ppm. C37H46N3OPTi (627.62):
calcd. C 70.81, H 7.39, N 6.70; found C 69.59, H 7.61, N 6.99.
P(CH2NPh)3Li3·(Et2O)1.5 (2a) and P(CH2NPh)3Li3(THF)5 (2a-
THF): A 1.6  solution of nBuLi (28.0 mL, 17.5 mmol, 3 equiv.) in
hexanes was added dropwise to a stirred slurry of P(CH2NPh)3H3
(2.04 g, 5.84 mmol) in diethyl ether (80 mL) at 0 °C. After the ad-
dition of 2 equiv. of nBuLi the solution was clear. The addition of
the third equivalent precipitated a white solid. The solid was fil-
tered and dried under vacuum (2.17 g, 78%). The product is insolu-
ble in toluene, ether, or CH2Cl2. The addition of THF generates
the more soluble THF adduct. This adduct is soluble in THF and
CH2Cl2 but decomposes within an hour at room temperature in
the latter. Crystals of the THF adduct suitable for characterization
by X-ray diffraction were obtained from THF by slow evaporation.
[P(CH2NPh)3Ti]2-[µ-4,4Ј-O-3,3Ј,5,5Ј-(Me2C6H2)2O-] (5a): 4,4Ј-
HO[3,3Ј,5,5Ј-(Me2C6H2)2]OH (121 mg, 0.5 mmol) was added to a
solution of P(CH2NPh)3TiNMe2 (438.3 mg, 1.0 mmol) in 50 mL of
toluene. The solution was stirred for 48 h. The solvent was removed
under vacuum and the remaining red solid was rinsed with a small
portion of cold pentane, and then dried under vacuum (277 mg,
51%). 1H NMR (C6D6, 300 MHz, 298 K): δ = 2.24 [s, 12 H,
3
1H NMR ([D8]THF, 500.1 MHz, 298 K): δ = 1.12 (t, J = 7.0 Hz,
2
9 H, OCH2CH3) 3.39 (q, 3J = 7.0 Hz, 6 H, OCH2CH3), 3.47 (d,
C6H2(CH3)2], 3.93 (d, JPH = 7.0 Hz, 12 H, PCH2), 6.73 (m, 6 H,
3
2JPC = 7.0 Hz, 6 H, PCH2), 6.09 (t, 3 H, Ph p-H), 6.42 (d, JHH
=
Ph p-H), 6.95 (d, JHH = 8.3 Hz, 6 H, Ph m-H), 7.10 (m, 2 H, C6H4),
7.17 (s, 4 H, C6H2) ppm. 13C{1H} NMR (C6D6, 125.8 MHz,
298 K): δ = 18.4 [s, C6H2(CH3)2], 45.6 (d, JPC = 20.7 Hz, PCH2),
113.8, 117.0, 121.5, 127.7, 129.5, and 135.7 (s, C6H5, C6H2), 153.9
(s, ipso-C6H5), 164.2 (s, ipso-O-C6H2) ppm. 31P{1H} NMR (C6D6,
8.3 Hz, 6 H, Ph o-H), 6.85 (m, 6 H, Ph m-H) ppm. 31P{1H} NMR
([D8]THF, 202.5 MHz, 298 K): δ = –22.15 (s) ppm. 13C{1H} NMR
([D8]THF, 125.8 MHz, 298 K): δ = 15.9 (s, OCH2CH3), 50.3 (d,
JPC = 12 Hz, PCH2), 110.9, 114.2, 129.3 (s, o,m,p-Ph), 164.2 (m,
ipso-C) ppm. 7Li NMR ([D8]THF, 116.7 MHz, 298 K): δ = 1.34 (s)
ppm. C27H36Li3N3O1.5P (478.39): calcd. C 67.79, H 7.58, N 8.78;
found C 68.08, H 7.49, N 8.74.
202.5 MHz, 298 K):
δ = –78.6 (s) ppm. C58H58N6O2P2Ti2
(1028.80): calcd. C 67.71, H 5.68, N 8.17; found C 67.37, H 5.58,
N 7.89.
P(CH2N-3,5-Me2C6H3)3Li3(Et2O)1.5 (2b):
nBuLi (9.4 mL, 15 mmol) in hexanes was added dropwise to a
stirred slurry of P(CH2NH-3,5-Me2C6H3)3 (2.15 g, 5 mmol) in di-
A
1.6  solution of
[P(CH2NPh)3Ti]2(µ-O) (6a): Solid Na2SO4·10H2O (16.1 mg,
0.5 mmol H2O) was added to P(CH2NPh)3TiNMe2 (438.3 mg,
1.0 mmol) dissolved in 50 mL of toluene and 10 mL of THF. The
478
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Titanium and Zirconium Complexes for Organometallic Polymers
solution was stirred for two weeks. The solvent was removed under
vacuum and the remaining red solid was rinsed with a small por-
tion of cold pentane, and then dried under vacuum (200 mg, 49%).
X-ray quality crystals were obtained by recrystallization from tolu-
ene; both trigonal and a monoclinic pseudopolymorphs were iden-
tified by X-ray crystallography. 1H NMR (C6D6, 300 MHz, 298 K):
298 K): δ = –70.8 (s) ppm. C31H43N4PZr (593.90): calcd. C 62.69,
H 7.30, N 9.43; found C 62.50, H 6.99, N 9.12.
P(CH2NPh)3ZrCl(THF) (9a): Solid P(CH2NPh)3ZrNEt2 (8a)
(1.17 g, 2.0 mmol) was added to a slurry of HNEt3Cl (275 mg,
2.0 mmol) in 50 mL of toluene. The pale yellow solution was stirred
1 h, then 5 mL of THF was added. The solvent was removed under
vacuum and the remaining yellow solid was rinsed with a small
portion of pentane, and then dried under vacuum (0.91 g, 84.1%).
1H NMR (C6D6, 300 MHz, 298 K): δ = 0.74 (m, 4 H, OCH2), 3.47
2
δ = 3.68 (d, JPH = 7.8 Hz, 12 H, PCH2), 6.68 (t, J = 7.3 Hz, 6 H,
Ph p-H), 6.80 (d, J = 8.2 Hz, 6 H, Ph o-H), 6.92 (t, J = 7.8 Hz, 6
H, Ph m-H) ppm. 13C{1H} NMR (C6D6, 125.8 MHz, 298 K): δ =
45.4 (d, JPC = 19.8 Hz, PCH2), 117.2, 121.6 and 129.4 (s, C6H5),
153.8 (s, ipso-C) ppm. 31P{1H} NMR (C6D6, 202.5 MHz, 298 K):
δ = –39.3 (s) ppm. C42H42N6OP2Ti2 (804.50): calcd. C 62.70, H
5.26, N 10.45; found C 62.40, H 5.14, N 10.52.
2
(m, 4 H, OCH2CH2), 3.81 (d, JPH = 7.0 Hz, 6 H, PCH2), 6.77 (t,
3 H, Ph p-H), 6.98 (d, 6 H, Ph o-H), 7.16 (m, 6 H, Ph m-H) ppm.
13C{1H} NMR (C6D6, 125.8 MHz, 298 K): δ = 25.4 (s, OCH2),
44.1 (d, JPC = 21 Hz, PCH2), 72.8 (s, OCH2CH2) 117.8 and 129.5
(s, Ph o-C and m-C), 120.4 (s, Ph p-C), 153.4 (d, ipso-C) ppm.
31P{1H} NMR (C6D6, 121.5 MHz, 298 K): δ = –71.5 (s) ppm.
C25H29ClN3OPZr (545.17): calcd. C 55.08, H 5.36, N 7.71; found
C 54.83, H 5.48, N 8.02.
P(CH2N-3,5-Me2C6H3)3Ti-µ-O-Ti(NMe2)3
(7b):
Ti(NMe2)4
(224.2 mg, 1.0 mmol) and a 1.0  solution of H2O in diethyl ether
(1.0 mL, 1.0 mmol) were added to a solution of P(CH2N-3,5-
Me2C6H3)3TiNMe2 (522.3 mg, 1.0 mmol) in 50 mL of toluene. The
solution was stirred for 24 h and the solvents evaporated to dryness,
then 5 mL of pentane and 10 mL of hexamethyldisiloxane were
added. The solution was filtered and the remaining orange red solid
was rinsed with a small portion of cold pentane, and then dried
under vacuum (370 mg, 55%). X-ray quality crystals were grown
from toluene. 1H NMR (C6D6, 500 MHz, 298 K): δ = 2.27 (s, 18
P(CH2N-3,5-Me2C6H3)3ZrCl(THF) (9b): Solid P(CH2N-3,5-
Me2C6H3)3ZrNEt2 (8b) (2.93 g, 5.0 mmol) was added to a solution
of HNEt3Cl (0.688 g, 5.0 mmol) in 120 mL of toluene. The pale
yellow solution was stirred 1 h, then was added 12 mL of THF. The
solvent was removed under vacuum and the remaining yellow solid
was rinsed with a small portion of pentane, and then dried under
vacuum (2.80 g, 90%). 1H NMR (C6D6, 300 MHz, 298 K): δ = 0.79
(m, 4 H, OCH2), 2.20 (s, 18 H, PhCH3), 3.55 (m, 4 H, OCH2CH2),
2
H, ArCH3), 3.03 (s, 18 H, NMe2), 3.84 (d, JPH = 7.0 Hz, 6 H,
PCH2), 6.60 (s, 6 H, Ph o-H), 6.87 (s, 3 H, Ph p-H) ppm. 13C{1H}
NMR (C6D6, 125.8 MHz, 298 K): δ = 22.1 (s, ArCH3), 44.3 (s,
NMe2), 44.8 (d, JPC = 19.7 Hz, PCH2), 114.5, 122.2, and 138.3 (s,
Ph o-C, m-C and p-C), 153.8 (s, ipso-C) ppm. 31P{1H} NMR
(C6D6, 202.5 MHz, 298 K): δ = –62.9 (s) ppm. C33H51N6OPTi2
(674.51): calcd. C 58.76, H 7.62, N 12.46; found C 58.59, H 7.41,
N 11.99.
2
3.92 (d, JPH = 6.4 Hz, 6 H, PCH2), 6.45 (s, 6 H, Ph o-H), 6.72 (s,
3 H, Ph p-H) ppm. 13C{1H} NMR (C6D6, 125.8 MHz, 298 K): δ
= 21.7 (s, PhCH3), 25.1 (s, OCH2), 44.1 (d, JPC = 19.8 Hz, PCH2),
72.5 (s, OCH2CH2), 115.5 and 122.1 (s, Ph o-C and m-C), 138.2 (s,
Ph p-C), 153.1 (d, JCC = 2.7 Hz, ipso-C) ppm. 31P{1H} NMR
(C6D6, 121.5 MHz, 298 K): δ = –66.0 (s) ppm. C31H41ClN3OPZr
(629.33): calcd. C 59.16, H 6.57, N 6.68; found C 59.12, H 6.29, N
6.79.
P(CH2NPh)3ZrNEt2 (8a): Liquid Zr(NEt2)4 (3.246 g, 8.55 mmol)
was added to a solution of P(CH2NHPh)3 (2.987 g, 8.55 mmol) in
30 mL of toluene. The pale yellow solution was stirred 24 h. The
solvent was removed under vacuum and the remaining yellow solid
was rinsed with a small portion of pentane, and then dried under
vacuum (3.76 g, 86%). The product has only moderate solubility
in benzene at room temperature, but is quite soluble in hot benzene.
P(CH2NPh)3ZrCp (10a): Solid P(CH2NPh)3ZrCl(THF) (9a)
(545.17 mg, 1.0 mmol) was added to a solution of CpLi (72.03 mg,
1.0 mmol) in 50 mL of toluene. The yellow solution was stirred
20 h. The solvent was removed under vacuum and the remaining
yellow solid was rinsed with a small portion of pentane, and then
dried under vacuum (420 mg, 80%). 1H NMR (C6D6, 300 MHz,
298 K): δ = 3.90 (d, 2JPH = 7.3 Hz, 6 H, PCH2), 5.95 (s, 5 H, C5H5),
6.85 (d, 6 H, Ph o-H), 6.92 (t, 3 H, Ph p-H), 7.20 (m, 6 H, Ph m-
H) ppm. 13C{1H} NMR (C6D6, 125.8 MHz, 298 K): δ = 46.8 (d,
JPC = 23.1 Hz, PCH2), 72.8 (s, THF), 114.6, 121.9, 122.8, 129.3 (s,
Ph o-C, m-C, p-C, C5H5), 153.4 (s, ipso-C) ppm. 31P{1H} NMR
(C6D6, 121.5 MHz, 298 K): δ = –67.5 (s) ppm. C26H26N3PZr
(502.70): calcd. C 62.12, H 5.21, N 8.36; found C 62.37, H 5.48, N
8.02.
3
1H NMR (C6D6, 300 MHz, 298 K): δ = 1.01 (t, J = 7.0 Hz, 6 H,
3
2
NCH2CH3), 3.20 (q, J = 7.0 Hz, 4 H, NCH2CH3), 3.83 (d, JPH
= 6.4 Hz, 6 H, PCH2), 6.80 (d, 6 H, Ph o-H), 6.85 (t, 3 H, Ph p-
H), 7.23 (m,
6
H, Ph m-H) ppm. 13C{1H} NMR (C6D6,
125.8 MHz, 298 K): δ = 14.5 (s, NCH2CH3), 42.8 (s, ZrNCH2CH3),
44.5 (d, JPC = 23 Hz, PCH2), 117.8 and 129.7 (s, Ph o-C and m-
C), 120.2 (s, Ph p-C), 153.6 (d, ipso-C) ppm. 31P{1H} NMR (C6D6,
121.5 MHz, 298 K): δ = –75.2 (s) ppm. C25H31N4PZr (509.74):
calcd. C 58.91, H 6.13, N 10.99; found C 58.55, H 6.17, N 10.77.
P(CH2N-3,5-Me2C6H3)3ZrNEt2 (8b): Liquid Zr(NEt2)4 (3.79 g,
P(CH2N-3,5-Me2C6H3)3ZrCp(10b): SolidP(CH2N-3,5-Me2C6H3)3-
10.0 mmol) was added to a solution of P(CH2NH-3,5-Me2C6H3)3 ZrCl(THF) (9b) (629.33 mg, 1.0 mmol) was added to a solution of
(4.30 g, 10.0 mmol) in 50 mL of toluene. The pale yellow solution
was stirred 48 h. The solvent was removed under vacuum and the
remaining yellow solid was rinsed with a small portion of pentane,
and then dried under vacuum (4.12 g, 69.4%) The product has only
moderate solubility in benzene at room temperature, but is quite
soluble in hot benzene. 1H NMR (C6D6, 300 MHz, 298 K): δ =
CpLi (72.03 mg, 1.0 mmol) in 50 mL of toluene. The yellow solu-
tion was stirred 20 h. The solvent was removed under vacuum and
the remaining yellow solid was rinsed with a small portion of pen-
tane, and then dried under vacuum (530 mg, 90%). X-ray quality
crystals were obtained from slow evaporation of a toluene solution.
1H NMR (C6D6, 300 MHz, 298 K): δ = 2.23 (s, 18 H, PhCH3),
3
2
1.12 (t, J = 7.1 Hz, 6 H, NCH2CH3), 2.23 (s, 18 H, PhCH3), 3.37
4.00 (d, JPH = 6.7 Hz, 6 H, PCH2), 6.18 (s, 5 H, C5H5), 6.60 (s, 3
(q, 3J = 7.1 Hz, 4 H, NCH2CH3), 3.95 (d, JPH = 6.8 Hz, 6 H,
H, Ph p-H), 6.68 (s, 6 H, Ph o-H) ppm. 13C{1H} NMR (C6D6,
2
PCH2), 6.52 (s, 6 H, Ph o-H), 6.55 (s, 3 H, Ph p-H) ppm. 13C{1H} 125.8 MHz, 298 K): δ = 21.8 (s, PhCH3), 47.0 (d, JPC = 23.1 Hz,
NMR (C6D6, 125.8 MHz, 298 K): δ = 14.6 (s, NCH2CH3), 22.1 (s,
PhCH3), 42.8 (s, ZrNCH2CH3), 44.9 (d, JPC = 22.0 Hz, PCH2),
115.9 and 122.2 (s, Ph o-C and m-C), 138.9 (s, Ph p-C), 153.8 (d,
JCC = 2.7 Hz, ipso-C) ppm. 31P{1H} NMR (C6D6, 121.5 MHz,
PCH2), 114.6, 120.8, 123.8, 138.4 (s, Ph o-C, m-C, p-C, C5H5),
159.9 (s, ipso-C) ppm. 31P{1H} NMR (C6D6, 121.5 MHz, 298 K):
δ = –66.9 (s) ppm. C32H38N3PZr (586.86): calcd. C 65.49, H 6.53,
N 7.16; found C 65.68, H 6.64, N 6.69.
Eur. J. Inorg. Chem. 2008, 471–482
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
479

H. Han, S. A. Johnson
–57.1 (s) ppm.
FULL PAPER
[P(CH2NPh)3Zr]2(η5:η5-C10H8)
(11a):
Solid
P(CH2NPh)3-
NMR (C6D6, 121.5 MHz, 298 K):
δ
=
ZrCl(THF) (9a) (545.17 mg, 1.0 mmol) was added to a solution of
(C10H8)Li2[48] (72 mg, 0.5 mmol) in 50 mL of toluene. The solution
was stirred 12 h and filtered to remove the solid. The solvent was
removed under vacuum and the remaining yellow solid was rinsed
with a small portion of pentane, and then dried under vacuum
(C26H26N3PZr)2 (1005.4): calcd. C 62.12, H 5.21, N 8.36; found C
61.79, H 5.64, N 8.47.
[P(CH2N-3,5-Me2C6H3)3Zr]2(η5:η5-C10H8) (11b): P(CH2N-3,5-
Me2C6H3)3ZrCl(THF) (9b) (629.33 mg, 1.0 mmol) was added to a
[48]
(205 mg, 40%). 1H NMR (C6D6, 300 MHz, 298 K): δ = 3.89 (d, solution of (C10H8)Li2
(72 mg, 0.5 mmol) in 50 mL of toluene.
2JPH = 7.3 Hz, 12 H, PCH2), 5.49 (s, 4 H, C10H8), 5.93 (s, 4 H,
C10H8), 6.70 (d, 6 H, Ph o-H), 6.90 (t, 3 H, Ph p-H), 7.20 (m, 6 H,
Ph m-H) ppm. 13C{1H} NMR (C6D6, 125.8 MHz, 298 K): δ = 46.9
(d, JPC = 23.0 Hz, PCH2), 113.9 and 118.8, 123.1, 129.2, 129.8,
138.9 (s, Ph o-C, m-C, p-C, C10H8), 158.8 (s, ipso-C) ppm. 31P{1H}
The solution was stirred 12 h and filtered to remove the solid. The
solvent was removed under vacuum and the remaining yellow solid
was rinsed with a small portion of pentane, and then dried under
vacuum (280 mg, 48%). X-ray quality crystals were obtained from
slow evaporation of a mixture of benzene and hexamethyldisilox-
Table 1. Crystallographic data and structure refinement for 2a-THF, 4b, 6a, 7b, 10b and 11b.
2a-THF
4b
6a
6a
Empirical formula
Formula weight
Crystal system
a [Å]
b [Å]
c [Å]
C41H61Li3N3O5P
727.72
orthorhombic
25.863(14)
14.907(8)
10.978(6)
90
90
90
4232(4)
Pna21
C37H46N3OPTi·0.5(C5H12) C42H42N6OP2Ti2
C49H50N6OP2Ti2
896.69
monoclinic
23.062(2)
10.0301(10)
19.319(2)
90
90.8680(10)
90
4468.3(8)
Pc
663.71
804.56
trigonal
13.0770(14)
13.0770(14)
20.452(4)
90
triclinic
14.225(3)
14.471(3)
20.351(5)
71.232(3)
77.687(3)
68.183(3)
3661.6(14)
P-1
α [°]
β [°]
90
120
γ [°]
V [Å3]
3028.8(8)
R-3
Space group
Z value
4
4
3
4
Dcalcd. [g/cm3]
µ (Mo-Kα) [mm–1]
Temperature [K]
2θmax [°]
1.142
0.108
293(2)K
50.0
1.204
0.311
173(2)
50.0
1.323
0.515
173(2)
55.0
1.333
0.473
173(2)
55.0
Total number of reflections
Unique reflections, Rint
Transmission factors
Reflections with IՆ2σ(I)
Number of variables
Reflections/parameters
R; wR2 (all data)
GOF
17447
35194
11068
48484
6005; 0.0413
0.94–0.98
3834
471
12.7
0.078; 0.142
0.919
0.421, –0.196
12848; 0.0538
0.89–0.98
9800
825
15.6
0.1008; 0.1790
1.130
0.667, –0.548
1548; 0.0496
0.86–0.90
1356
81
19.1
0.0709; 0.1351
1.195
0.561, –0.437
19725; 0.0323
0.80–0.83
18481
1083
18.2
0.0625; 0.1398
1.162
0.703, –0.527
Residual density [e–/Å3]
7b
10b
11b
Empirical formula
Formula weight
Crystal system
a [Å]
b [Å]
c [Å]
C33H51N6OPTi2
674.57
trigonal
15.861(2)
15.861(2)
24.504(7)
90
90
120
5339(2)
R-3
C32H38N3PZr
586.84
triclinic
C76H86N6P2Zr2
1327.89
monoclinic
15.120(2)
13.8406(19)
18.128(3)
90
113.6850(10)
90
3474.2(8)
P21/n
11.4611(9)
15.4190(12)
18.5870(14)
101.2880(10)
107.8600(10)
102.3990(10)
2930.1(4)
P-1
α [°]
β [°]
γ [°]
V [Å3]
Space group
Z value
6
4
2
Dcalcd. [g/cm3]
µ (Mo-Kα) [mm–1]
Temperature [K]
2θmax [°]
1.259
0.527
173(2)
55.0
1.330
0.455
173(2)
50.0
1.269
0.392
173(2)
55.0
Total number of reflections
Unique reflections, Rint
Transmission factors
Reflections with IՆ2σ(I)
Number of variables
Reflections/parameters
R; wR2 (all data)
GOF
16998
28289
37628
2667; 0.0820
0.88–0.91
1808
134
19.9
0.0790; 0.1533
1.057
0.539, –0.599
10288; 0.0208
0.67–0.85
9362
679
15.2
0.0331; 0.0785
1.054
0.390, –0.260
7869; 0.0473
0.92–0.99
6849
394
20.0
0.0661; 0.1191
1.210
0.785, –0.660
Residual density [e–/Å3]
480
www.eurjic.org
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2008, 471–482

Titanium and Zirconium Complexes for Organometallic Polymers
ane solution. 1H NMR (C6D6, 300 MHz, 298 K): δ = 2.18 (s, 36
H, PhCH3), 3.86 (d, JPH = 7.2 Hz, 12 H, PCH2), 5.70 (s, 4 H,
C10H8), 6.17 (s, 4 H, C10H8), 6.50 (s, 6 H, Ph o-H), 6.55 (s, 3 H,
Ph p-H) ppm. 13C{1H} NMR (C6D6, 125.8 MHz, 298 K): δ = 21.8
(s, PhCH3), 48.1 (d, JPC = 22.2 Hz, PCH2), 112.6 and 121.8, 124.0,
138.2 (s, Ph o-C, m-C, p-C, C10H8), 158.9 (s, ipso-C) ppm. 31P{1H}
[5]
[6]
[7]
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2
[9]
NMR (C6D6, 121.5 MHz, 298 K):
δ
=
–56.3 (s) ppm.
(C32H38N3PZr)2 (1173.72): calcd. C 65.49, H 6.53, N 7.16; found
C 65.76, H 6.83, N 7.53.
[10]
[11]
[12]
Cl(CO)Rh[P(CH2NPh)3Ti]2O (12a): The dinuclear oxo-bridged ti-
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insoluble polymer begins to precipitate. The solution was stirred
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(67 mg, 87%). IR (KBr pellet):
ν
˜
=
1975.2 cm–1.
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[19]
X-ray Crystallography: The X-ray structures were obtained at low
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a Bruker APEX CCD diffractometer using a graphite monochro-
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Acknowledgments
We thank theNational Sciences and Engineering Council (NSERC)
of Canada and the Ontario Research and Development Challenge
Fund (University of Windsor Centre for Catalysis and Materials
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H. Han, S. A. Johnson
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