A general and facile one-step synthesis of imido-titanium(IV) complexes: Application to the synthesis of compounds containing functionalized or chiral imido ligands and bimetallic diimido architectures

FULL PAPER

DOI: 10.1002/ejic.200600475

A General and Facile One-Step Synthesis of Imido–Titanium(IV) Complexes:

Application to the Synthesis of Compounds Containing Functionalized or

Chiral Imido Ligands and Bimetallic Diimido Architectures

Christian Lorber,*^[a]Robert Choukroun,^[a]and Laure Vendier^[a]

Keywords: Imido / N ligands / Multiple bonds / Titanium / Synthesis design

One-pot reactions of Ti(NMe₂)₄with a wide range of primary

alkyl, aryl, and silylamines RNH₂in the presence of excess

chlorotrimethylsilane produced the corresponding imido–

the imido moiety have been prepared. The use of enantio-

merically pure primary amines affords the first group of tita-

nium complexes that contain chiral imido groups, and the

titanium(IV) complexes [Ti(=NR)Cl₂(NHMe₂)₂] (1a–j), in which use of diamines produces diimido complexes. Alternatively,

R = tBu, 1-adamantane, Ph₃C, Ph₃Si, Ph, 2,6-iPr₂–C₆H₃, 2,6-

Cl₂–C₆H₃, 2,6-Br₂–4-Me–C₆H₂, C₆F₅, and 3,5-(F₃C)₂–C₆H₃.

This general synthesis, which starts from commercially avail-

able reagents, represents a simple and direct route to imido

complexes. Reaction of complexes 1 with pyridine afforded

the six-coordinate tris-pyridine adducts [Ti(=NR)Cl₂(Py)₃] (2).

Another advantage of this method is its tolerance to other

functional groups; complexes that contain halides, ether, di-

alkylamino, cyano, ethynyl, olefin, and nitro substituents on

CH₃I has been used as an alkylating agent to generate tita-

nium–imido complexes of the type [Ti(NR)I₂(THF)₂]₂. All

compounds were fully characterized by spectroscopic meth-

ods (IR, ¹H NMR, ¹³C NMR) and elemental analysis. Some of

the compounds were also analyzed by single-crystal X-ray

diffraction studies.

Germany, 2006)

As part of an ongoing study of vanadium complexes sup-

ported by various ligands,^[20]we recently described the syn-

thesis and molecular structure of the new terminal aryl–

imido, and rare Cp-free, vanadium(IV)complex [V(=N–2,6-

iPr₂–C₆H₃)Cl₂(NHMe₂)₂].^[5]We have further demonstrated

that various aryl–imido groups could be very conveniently

introduced by a one-pot synthesis from V(NMe₂)₄, the cor-

responding aniline, and chlorotrimethylsilane.^[21]We have

also studied the coordination chemistry of these new com-

plexes with N- or P-donor neutral ligands,^[21,22]and the re-

sults suggest that imido compounds of this type could lead

to a large variety of vanadium coordination compounds.

Furthermore, some of these imido–vanadium species have

been shown to possess catalytic activities in olefin polymeri-

zation^[5]and in alkyne hydroamination.^[13a]Terminal

Introduction

The last two decades have witnessed a strong interest in

the coordination chemistry of transition-metal complexes

that contain imido ligands [NR]^2–(R = alkyl or aryl).^[1]

The dianionic π-donor terminal imido functional group is

involved in many facets of chemistry that can be subdivided

into two types: (1) reactions in which the imido group acts

as a spectator ligand, the [NR]^2–moiety is isolobal with

[C₅H₅]^–[2](e.g. in alkene metathesis^[3]or olefin polymeriza-

tion^[1c,4–6]), (2) reactions in which the M = NR linkage itself

is involved in stoichiometric or catalytic transformations

such as metathesis reactions (with imines,^[7]nitro- and

nitrosoarenes,^[8]or oxo–imido exchange^[9]), C–H acti-

vation,^[10]reactions with unsaturated C–C^[11]or C–X

bonds,^[12]alkyne hydroaminations,^[13,14]carboamination

reactions,^[15]and ring-opening reactions of strained hetero-

cycles.^[10d,16]Moreover, some imido derivatives have also

found applications in material chemistry (OMCVD,^[17]

polyoxometalate^[18]) and have been implicated in the

ammoxidation of propene.^[19]

imido–titanium complexes [Ti(=N–tBu)Cl₂L_n] [L_n

=

(NHMe₂)₂, Py₂, Py₃, TMEDA] have proven to be very use-

ful synthons for the preparation of many other imido deriv-

atives through chloride and/or ligand base exchange me-

tathesis; aryl– and silyl–imido derivatives are available by

transimination reactions with the appropriate aryl and silyl-

amine.^{[6a,13d,17c,23–26]}Some of these imido–titanium com-

plexes present potential activity in olefin polymerization,^[6]

alkyne hydroamination,^[13]and have been used for the syn-

thesis of TiN thin films,^[17a–17c]which further justifies the

quest for the cheapest and the most direct route for the

preparation of such useful precursors.

[a] Laboratoire de Chimie de Coordination, CNRS UPR 8241, lié

par convention à l’Université Paul Sabatier,

205 route de Narbonne, 31077 Toulouse Cedex 04, France

Fax: +33-5-61-55-30-03

E-mail: lorber@lcc-toulouse.fr

Supporting information for this article is available on the

WWW under http://ww w .eurjic.org or from the author.

Eur. J. Inorg. Chem. 2006, 4503–4518

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FULL PAPER

Two routes are commonly employed for the preparation pure amines (to afford chiral imido functions) and diamines

of the now widely used synthon [Ti(=N–R)Cl₂L_n] [L_n(to afford diimido complexes). Related complexes with pyri-

=

(NHMe₂)₂, Py₃]. In the first method, [Ti(=N–tBu)Cl₂Py₃] dine ligands prepared by the substitution of the NHMe₂

is prepared from TiCl₄, tBuNH₂, and pyridine.^[23]Neverthe- ligands in [Ti(=NR)Cl₂(NHMe₂)₂] by pyridine (Py) donors

less, other analogues (i.e. aryl–imido) cannot be obtained is also described. Finally, an alternative preparation for the

this way, and their synthesis requires a second step that con- related iodo analogue complex [Ti(NAr)I₂(thf)₂]₂is also de-

sists of an imido/amine exchange reaction (transimination) scribed; this method is based on the use of CH₃I instead of

of [Ti(=N–tBu)Cl₂Py₃] with the appropriate arylamine.^[23]Me₃SiCl (Scheme 3).

Moreover, the presence of pyridine renders these com-

pounds somewhat insoluble, and pyridine ligands may be

unwanted for certain applications. During the course of our

studies,

imido–titanium

complexes

[Ti(=N–R)Cl₂-

Results and Discussion

(NHMe₂)₂] have been prepared by Mountford et al. with a

procedure based on the reaction of Ti(NMe₂)₂Cl₂with a

primary alkyl- or arylamine.^[26]Although this route appears

more general than the one with TiCl₄, the precursor

Ti(NMe₂)₂Cl₂is not commercially available and needs to be

prepared from TiCl₄and Ti(NMe₂)₄.^[27]

In this paper, and as an extension of our imido–vana-

dium method^[21]to titanium, we report on a very conve-

nient, one-pot synthesis of a series of alkyl–, aryl–, and si-

lyl–imido derivatives of titanium(IV) complexes of the gene-

ral formula [Ti(=NR)Cl₂(NHMe₂)₂] (1), where R is an

alkyl-, an aryl-, or a silyl group. Part of this work [synthesis

of Ti(=NPh)Cl₂(NHMe₂)₂] has been previously communi-

cated.^[13a]Our method presents the advantage to afford the

imido derivative in one single step with the use of a very

simple one-pot synthesis from commercially available

Ti(NMe₂)₄, the corresponding primary amine RNH₂, and

This work constitutes a systematic investigation of the

synthetic and structural chemistry of imido–titanium(IV)

complexes of the general formula [Ti(=NR)Cl₂(NHMe₂)₂]

that are prepared directly from a one-pot reaction of

Ti(NMe₂)₄, RNH₂, and Me₃SiCl, as well as some related

compounds. The synthesis and proposed structures of the

imido complexes of titanium(IV) are summarized in

Schemes 1–3. The structures of eleven complexes are set out

in Figures 2–7, and Figures 9, 10, 12, and 14, selected met-

ric data are collected in Tables 1 and 2.

1. General Synthesis of the Imido Complexes [Ti(=NR)-

Cl₂(NHMe₂)₂] and [Ti(=NR)Cl₂Py₃]

In our previous study,^[21]we described the synthesis of

an excess of chlorotrimethylsilane. Another important goal paramagnetic aryl–imido–vanadium complexes [V(=NAr)-

of this study was to explore the selectivity and the func- Cl₂(NHMe₂)₂] from the reaction of an aniline with

tional group tolerance of the reaction. Amines that contain V(NMe₂)₄in toluene followed by the addition of an excess

additional functionality on their skeletons (e.g. ether, dialk- of chlorotrimethylsilane. Inspired by this result, we at-

ylamino, cyano, ethynyl, olefin, or nitro substituents) were tempted to use a similar one-pot synthesis for the pro-

successfully used to generate original imido derivatives. In duction of related titanium–imido analogue complexes, and

consequence, our procedure appears to be applicable to a the scope of this method was first illustrated with a range

wide range of primary amines including enantiomerically of primary amines listed in Scheme 2.

Scheme 1. Designation of imido–titanium complexes described in this study.

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Eur. J. Inorg. Chem. 2006, 4503–4518

A General and Facile One-Step Synthesis of Imido–Titanium(IV) Complexes

FULL PAPER

Scheme 2. General synthesis of imido–titanium(IV) complexes 1 and 2.

When a toluene solution of Ti(NMe₂)₄is reacted with

Single crystals of 2d were grown from a CH₂Cl₂/pyridine

one equiv. of RNH₂[with R = tBu, 1-adamantyl, Ph₃C, solution of 2d layered with pentane at room temp. and were

Ph₃Si, Ph, 2,6-iPr₂–C₆H₃, 2,6-Cl₂–C₆H₃, 2,6-Br₂–4-Me– analyzed by X-ray crystallography. A thermal ellipsoid plot

C₆H₂, C₆F₅, and 3,5-(F₃C)₂–C₆H₃] and an excess of chloro- is presented in Figure 1 along with selected bond lengths

trimethylsilane^[28](typically about 8 equiv.) at room temp. and angles in Table 1.

overnight, yellow–orange compounds [Ti(=NR)Cl₂-

(NHMe₂)₂] [R = tBu (1a), 1-adamantyl (1b), Ph₃C (1c),

Ph₃Si (1d), Ph (1e), 2,6-iPr₂–C₆H₃(1f), 2,6-Cl₂–C₆H₃(1g),

2,6-Br₂–4-Me–C₆H₂(1h), C₆F₅(1i), and 3,5-(F₃C)₂–C₆H₃

(1j)] are formed exclusively (Scheme 2). These complexes

often separated by crystallization (while the reaction pro-

ceeds or upon the addition of pentane) as large, generally

yellow–orange (for alkyl–imido) or red (for aryl–imido)

needles or crystals with good yields (73–96%).

The detailed experimental protocols and full characteri-

zation are given in the Experimental Section. Compounds

1a–j have been characterized by infrared spectroscopy (with

strong ν_NHabsorptions around 3250 cm^–1), multinuclear

NMR spectroscopy, elemental analysis, and by X-ray struc-

ture determination for some (vide infra). The products are

consistent with the proposed structure of a monomeric five-

coordinate compound with 2 dimethylamine ligands that

Figure 1. Molecular structure of 2d with selected bond lengths [Å]

and angles [°], which shows 50% probability ellipsoids and partial

atom-labeling schemes. Hydrogen atoms are omitted for clarity.

occupy the axes of the bipyramid. This one-pot synthesis

cleanly affords a wide range of alkyl–, silyl–, and aryl–imido

complexes Ti(=NR)Cl₂(NHMe₂)₂. It is important to note

that titanium silyl–imido complexes remain comparatively

rarer than their alkyl- or aryl analogues.^{[10b,12d,25,29]}

Compound 2d adopts a pseudooctahedral geometry

around the metal center with mutually trans chloride and

pyridine ligands. The third pyridine ligand is disposed trans

to the imido group. Bond lengths and angles are unexcep-

tional and were found to be very similar to those observed

in titanium^[23,25]and vanadium^[21]analogues; the titanium–

nitrogen bond lengths of the imido fragment is

1.7110(13) Å, with an almost linear Ti–N_imido–Si angle

[171.12(9)°], and an average Ti–Cl ca. 2.39 Å. The trans Ti–

N(Py) of 2.4742(14) Å is significantly longer than the

average cis Ti–N(Py) bond lengths [2.224(2) Å], which re-

flects the trans-labilizing ability of the imido ligand.

When dissolved in pyridine, bis-dimethylamine adducts 1

are instantly and generally quantitatively converted into

tris-pyridine complexes [Ti(=NR)Cl₂(Py)₃] (2). In a few

cases, it has been reported that the substitution of NHMe₂

ligands by pyridine is difficult or produces mixed NHMe₂–

pyridine adducts.^[21,26]Within this study, we have only expe-

rienced difficulties (vide infra) in the synthesis of one com-

pound (namely 5 from 4). We will not insist on this substi-

tution reaction that has already been described by us on

vanadium analogues,^[21]and by Mountford on titanium

complexes,^[26]but these tris-pyridine complexes are gen-

erally obtained as large crystals with good X-ray quality

that facilitates their structural characterization, vide infra

(although they are sometimes poorly soluble in common

2. Tolerance to Functional Groups on the Imido Moiety in

[Ti(=NR)Cl₂(NHMe₂)₂] and [Ti(=NR)Cl₂Py₃] Complexes

organic solvents). In consequence, in this article we will re- Functionalized organoimido complexes of titanium, that is

fer to this substitution reaction only when a related tris- complexes that contain additional functional groups on the

pyridine–imido compound was structurally characterized.

imido moiety, are extremely rare.^[23,30]Since we have easy

Eur. J. Inorg. Chem. 2006, 4503–4518

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C. Lorber, R. Choukroun, L. Vendier

Table 1. Comparison of the average interatomic distances [Å] and angles [°] in Ti(=NR)Cl₂(NHMe₂)₂and Ti(=NR)Cl₂(Py)₃complexes.

FULL PAPER

1k

1o

1p

1s*

2d

2l

2r

Ti–N_imido

N_imido–C_ipso/Si

Ti–Cl

1.6955(18)

1.390(2)

2.3567(9)

2.3553(11)

2.2185(18)

2.2186(17)

–

1.7028(11)

1.3889(16)

2.3393(4)

2.3509(4)

2.2005(11)

2.2119(11)

–

1.700(2)

1.384(4)

2.3261(9)

2.3301(9)

2.207(3)

2.210(2)

–

1.682(4)

1.455(6)

2.3602(15)

2.3393(17)

2.196(5)

2.214(5)

–

1.7110(13)

1.7098(14)^[a]

2.3752(5)

2.4037(5)

–

1.726(2)

1.357(3)

2.3756(4)

1.6988(12)

1.4448(18)

2.4353(5)

2.3999(5)

–

Ti–N_NHMe

–

2

Ti–N_Py(trans)

Ti–N_Py(cis)

2.4742(14)

2.2140(14)

2.2339(14)

–

2.425(2)

2.2201(13)

2.4000(12)

2.2433(12)

2.2314(13)

–

H_NHMe···Cl

2.516

2.530

2.391

2.708

2.563

–

2

[b]

Ti–N_imido–C_ipso/Si

Cl–Ti–Cl

178.21(15)

132.86(3)

167.27(6)

96.39(8)

96.33(8)

–

113.97(7)

113.17(6)

–

153.63

151.20

N_Et–C_Ar

1.386(3)

178.86(10)

131.357(16)

169.29(4)

95.36(5)

95.31(5)

–

115.08(4)

113.54(4)

–

169.4(2)

134.01(4)

168.35(10)

93.64(11)

97.85(11)

–

115.41(10)

110.45(10)

–

168.8(4)

140.12(6)

160.43(16)

100.88(18)

98.65(19)

–

112.79(15)

107.04(15)

–

171.12(9)

180.0

164.59(3)

–

174.31(10)

163.780(18)

–

162.03(2)

–

N_NHMe–Ti–N_NHMe

2

N –Ti–N_NHMe

N_imido

2

N_Py(cis)–Ti–N_Py(cis)

_imido–Ti–Cl

169.87(5)

91.44(4)

99.15(5)

178.09(6)

–

169.32(7)

97.705(15)

168.24(4)

98.77(4)

97.37(4)

179.23(5)

–

N

N_imido–Ti–N_Py(trans)

N–H···Cl

169.32(7)

–

164.94

153.17

147.90

functional group

C=C 1.338(2) CϵC 1.183(5)

–

NϵC 1.144(4) CϵC 1.187(2)

C–CϵC

175.5(4)

NϵC–C

180.0

C–CϵC

178.93(18)

[a] N_imido–Si bond length. [b] Ti–N_imido–Si angle.

access to various Ti–imido complexes from readily available with the formation of the expected corresponding bis-di-

amines, it was of interest to probe the tolerance of our syn- methylamine adducts [Ti(=NAr)Cl₂(NHMe₂)₂] (1k–q) [with

thetic procedure towards the presence of functional groups Ar = p-Et₂N–C₆H₄(1k), p-NC–C₆H₄(1l), o-NC–C₆H₄

on the alkyl/arylamine backbone, and also to learn the sta- (1m), p-H₂C=CH–C₆H₄(1n), o-MeC=CH₂–C₆H₄(1o), m-

bility of the resulting functionalized imido compounds. The HCϵC–C₆H₄(1p), and m-O₂N–o-Me–C₆H₃(1q)]. Not sur-

added functionality of the organoimido compounds may prisingly, some of these compounds have been easily con-

serve as an anchor to graft the complexes to a support, and verted into their tris-pyridine adducts [Ti(=NAr)Cl₂(Py)₃]

their reactivity could be studied as well. We have already (2) by the addition of an excess of pyridine to the corre-

shown in the previous section that halides and CF₃-substi- sponding dimethylamine precursor. Only [Ti(=N–p-NC–

tuted anilines can be employed, and we have screened se- C₆H₄)Cl₂(Py)₃] (2l) will be described later on as its molecu-

veral other anilines and amines that contain ether, dialk- lar structure has been established (vide infra). These func-

ylamine, cyano, alkyne, olefin, or nitro groups under the tional organoimido species have been characterized by me-

same conditions used above [Ti(NMe₂)₄, RNH₂, Me₃SiCl, ans of spectroscopic methods (NMR, IR), and combustion

toluene, room temp.]. These amines are depicted in Fig- analysis. The solution ¹H- and ¹³C NMR spectroscopic

ure 2.

data present features similar to those of their nonfunctional

The general one-pot procedure proceeded as anticipated analogues – a single set of resonances for the coordinated

with anilines substituted with p-NEt₂, p-CN, o-CN, p- NHMe₂ligands (in 1) or two different pyridine ligands in

HC=CH₂, o-MeC=CH₂, m-CϵCH, and m-NO₂groups the ratio 2:1 (in 2), and resonances attributable to the or-

Figure 2. Functional amines used in this study.

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Eur. J. Inorg. Chem. 2006, 4503–4518

A General and Facile One-Step Synthesis of Imido–Titanium(IV) Complexes

FULL PAPER

ganoimido group. These data are consistent with the func-

tional group that does not interact with the metal center.

Indeed, according to the IR data, some of these functional

groups are clearly observed in their normal regions (ν_CϵN

2243, 2242, and 2221 cm^–1, respectively, for 1l, 1m, and 2l;

ν_C=C1624 and 1629 cm^–1, respectively, for 1n and 2o; ν_CϵC

2208 cm^–1for 1p; ν_NO1517 cm^–1for 1q).

When reacted with ²Ti(NMe₂)₄in the presence of chloro-

trimethylsilane, 1-ethynylcyclohexylamine gave the imido

complex Ti[=N(C₆H₁₀CϵCH)]Cl₂(NHMe₂)₂(1r). Again,

spectroscopic (¹H- and ¹³C NMR) data suggest that the

carbon–carbon triple bond does not coordinate to the tita-

nium center. The corresponding pyridine analogue [Ti[= N-

(C₆H₁₀CϵCH)]Cl₂(Py)₃] (2r), formed upon the addition of

excess pyridine to 1r, has been characterized by X-ray struc-

ture determination (vide infra) that clearly shows the free

CϵC–H fragment.

Figure 4. Molecular structure of 1o with selected bond lengths [Å]

and angles [°], which shows 50% probability ellipsoids and partial

atom-labeling schemes. Hydrogen atoms are omitted for clarity.

Single-crystals suitable for X-ray diffraction studies were

obtained for these functionalized organoimido compounds

from room temp. toluene (1k, 1o), cold toluene/pentane

(1p), or pyridine-toluene/pentane (2l, 2r) solutions. Thermal

ellipsoid plots are presented in Figures 3, 4, 5, 6, 7; selected

metric parameters are given in Table 1.

Figure 3. Molecular structure of 1k with selected bond lengths [Å]

and angles [°], which shows 50% probability ellipsoids and partial

atom-labeling schemes. Hydrogen atoms are omitted for clarity.

Figure 5. Molecular structure of 1p with selected bond lengths [Å]

and angles [°], which shows 50% probability ellipsoids and partial

atom-labeling schemes. Hydrogen atoms are omitted for clarity.

In the solid state, the molecular structure of the three

NHMe₂adducts (1k, 1o, 1p) is best described as distorted in the trigonal bipyridine with a Cl1–Ti–Cl2 angle of

trigonal bipyramid with axial dimethylamine ligands [τ = 132.86(3)°, 131.357(16)°, and 134.01(4) Å for 1k, 1o, and

0.58 (1k), 0.63 (1o), and 0.57 (1p)],^[31]with N_imido–Ti–Cl 1p, respectively, and mean Ti–Cl bond lengths of 2.36 Å,

angles in the range 110–115°, and N_imido–Ti–N

angles 2.34 Å, and 2.33 Å for 1k, 1o, and 1p, respectively. The two

NHMe₂

in the range 93–98°. The distances and angles associated trans dimethylamino ligands form the axis of the bipyra-

with the titanium center and the ligands are comparable to mid, and have mean Ti–N_NHMebonds of ca. 2.21 Å for the

2

those found in other [M(=NR)Cl₂(NHMe₂)₂] complexes (M three compounds. The supramolecular structure is domi-

= Ti,^[26]V^[21]). Adducts 1k, 1o, and 1p exhibit a short Ti– nated by Me₂N–H···Cl hydrogen bonding (NH···Cl bond

N_imidodistance of 1.6955(18) Å for 1k, 1.7028(11) Å for 1o, lengths are in the range 2.391 to 2.708 Å; associated N–

and 1.700(2) Å for 1p. The imido linkage is almost linear H···Cl angles are 164.94 to 147.64°); features that they share

[Ti–N_imido–C_ipsoangle

=

178.21(15), 178.86(10), and with Mountford’s related compounds.^[26]

169.4(2)°, respectively, in 1k, 1o, and 1p], and is consistent

An ORTEP drawing of the molecular structure of 2l and

with the donation of the lone pair on nitrogen to an ac- 2r is shown in Figures 6 and 7, respectively. Crystals of 2r

ceptor orbital on titanium (the imido Ti–N bond can be contain one residual molecule of pyridine (not shown in

considered as a triple bond). The crystal structure determi- Figure 6). In 2l, the Ti–N_imidoand CϵN vectors lie on a

nations also unambiguously show noninteracting func- crystallographic two-fold rotation axis. The pendant func-

tional -NEt₂(1k), -C(Me)=CH₂(1o), and –CϵCH (1p) tional cyano (2l) and ethynyl (2r) group on the imido moie-

groups, with normal metric parameters that are listed in ties do not bind to the titanium center. Compounds 2l and

Table 1. Both of the chlorine atoms occupy equatorial sites 2r adopt a pseudooctahedral geometry around the titanium

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C. Lorber, R. Choukroun, L. Vendier

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center similar to the one described above for 2d (with mutu- R^o= 2-EtO–C₆H₄(3), and CH₂(CHO(CH₂)₃) (4)] (Fig-

ally trans chloride and pyridine ligands, the third pyridine ure 8), as judged by spectroscopic (NHMe₂/NR^o, 1:1) and

1

ligand is disposed trans to the imido group). Bond lengths analytical data. The H- and ¹³C NMR spectra of 3 reveal

and angles are normal, and found to be very similar to diastereotopic methyl groups for the NHMe₂ligand. Be-

those observed in titanium^[23]and vanadium^[21]analogues, cause of their poor solubility in common organic solvents,

as well as in previously described 2d (Table 1). The tita- these compounds are probably imido-bridged dimers with

nium–nitrogen bond length of the imido fragments are the oxygen atom coordinated to the metal center.

1.726(2) Å (2l) and 1.6988(12) Å (2r) with an angle Ti–

N

_imido–C_ipsoof 180.0° (2l) and 174.31(10)° (2r), and Ti–Cl

bond length of 2.3756(4) Å (2l) and 2.4353(5) and

2.3999(5) Å (2r).

Figure 8. Proposed structure for complexes 3–5.

Indeed, molecular structure determination (Figure 9) has

unambiguously established that 3 is the centrosymmetric di-

mer [Ti[µ₂-[N]-η¹[O]-N–2-EtO–C₆H₄]Cl₂(NHMe₂)]₂, with

two aryl–imido ligands that bridge two (Me₂HN)Cl₂Ti moi-

eties. The O atom of the ether function is coordinated cis

to the N atom of its own ligand set, trans to the N atom of

the other imido group, and the chlorine atoms are mutually

cis to one another. The coordination geometry of titanium

is distorted octahedral. The Ti₂N₂core is planar (torsion

angle 0°) and is characterized by a short Ti···Ti distance

common in imido dimers^[32][Ti1···Ti1Ј = 2.889(3) Å] with

two Ti–N_imidobond lengths of 1.830(6) Å and 2.027(6) Å.

The (Me₂HN)Cl₂Ti moiety is normal with the expected Ti–

N_amineand Ti–Cl bond lengths and angles [Ti–N_amine

2.226(6) Å, Ti–Cl avg. 2.346 Å].

Figure 6. Molecular structure of 2l with selected bond lengths [Å]

and angles [°], which shows 50% probability ellipsoids and partial

atom-labeling schemes. Hydrogen atoms are omitted for clarity.

Figure 7. Molecular structure of 2r with selected bond lengths [Å]

and angles [°], which shows 50% probability ellipsoids and partial

atom-labeling schemes. Hydrogen atoms and residual solvent (one

molecule of pyridine) of crystallization are omitted for clarity.

Figure 9. Molecular structure of 3 with selected bond lengths [Å]

and angles [°], which shows 50% probability ellipsoids and partial

atom-labeling schemes. Hydrogen atoms are omitted for clarity.

Unlike the previous functional anilines, however, amines

that contain an additional ether-function {i.e. 2-EtO–

C₆H₄NH₂

and

tetrahydrofurfurylamine

[H₂NCH₂-

Addition of pyridine to 4 affords the pyridine complex

(CHO(CH₂)₃)]} did not generate the bis-dimethylamine ad- [Ti(µ2-[N]-η¹[O]–NR^o)Cl₂(Py)]₂(5) [R^o

= CH₂(CHO-

duct, but rather reacted to afford the mono-dimethylamine (CH₂)₃)] and its molecular structure has also been assessed

adduct of the general formula [Ti(NR^o)Cl₂(NHMe₂)] [with on the basis of X-ray structure determination. The ORTEP

4508

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Eur. J. Inorg. Chem. 2006, 4503–4518

A General and Facile One-Step Synthesis of Imido–Titanium(IV) Complexes

FULL PAPER

drawing is shown in Figure 10, and selected bond lengths dral metal coordination spheres. Each distorted octahedron

and angles are given in Table 2. Like 3, compound 5 is di- is completed by two mutually cis chlorine atoms [Ti–Cl avg.

meric in the solid state, and the overall geometry, distances, 2.367(2) Å, Cl–Ti–Cl 90.69(4)°], one pyridine ligand [Ti–

and angles are broadly comparable to those of 3. Complex N_Py2.254(3) Å] and the O atom of the furan link [Ti–O

5 is an imido-bridged dimer with two edge-sharing octahe- 2.177(3) Å]. The Ti₂N₂core is planar (torsion angle 0°) and

is characterized by a short Ti···Ti distance [2.8502(13) Å].

The disymmetric imido bridges are characterized by two

Ti–N_imidobond lengths of 1.821(3) Å and 2.013(3) Å, that

are longer by ca. 0.1/0.3 Å than those generally observed in

terminal imido complexes. The angle formed by the bridg-

ing nitrogen atoms with the two metal centers [Ti–N_imido

–

TiЈ = 95.92(14)°] deviates significantly from that expected

for an sp²nitrogen atom. The (Py)Cl₂Ti moiety is normal

with the expected Ti–N_Pyand Ti–Cl bond lengths and

angles [Ti–N_Py2.254(3) Å, Ti–Cl avg. 2.367(2) Å].

3. Application to the Synthesis of Diimido Complexes and

Chiral Imido Complexes

In relation to the possible use of chiral imido complexes

in catalysis for stereoselective olefin polymerization^[33]and

their involvement in alkyne/alkene hydroamination,^[34]we

have initiated the synthesis of chiral imido groups on tita-

nium complexes from enantiomerically pure chiral amines.

Figure 10. Molecular structure of 5 with selected bond lengths [Å]

and angles [°], which shows 50% probability ellipsoids and partial

atom-labeling schemes. Hydrogen atoms are omitted for clarity.

Table 2. Comparison of the average interatomic distances [Å] and angles [°] in dimers 3, 5, 6*, and 8.

3

5

6*

8

Ti–N_imido

Ti1–N1 1.830(6)

Ti1–N1Ј 2.027(6)

Ti1–N1 2.013(3)

Ti1–N1Ј 1.821(3)

Ti1–N1 1.821(4)

Ti2–N1 1.965(4)

Ti1–N2 1.840(4)

Ti2–N2 1.971(4)

N1–C1 1.494(6)

N2–C9 1.487(6)

Ti1–Cl1 2.2542(17)

Ti1–Cl2 2.2482(16)

Ti2–Cl3 2.3500(16)

Ti2–Cl4 2.3588(16)

Ti2–N3 2.215(4)

Ti2–N4 2.233(4)

Ti1–N1 1.719(4)

Ti2–N5 1.710(4)

N_imido–C_ipso

N1–C1 1.395(10)

N1–C10 1.452(5)

N1–C16 1.374(6)

N5–C27 1.378(6)

Ti1–Cl1 2.4075(16)

Ti1–Cl2 2.4059(18)

Ti2–Cl3 2.4185(17)

Ti2–Cl4 2.3893(16)

Ti1–N2 2.249(5)

Ti1–N3 2.386(4)

Ti1–N4 2.235(5)

Ti2–N6 2.223(4)

Ti2–N7 2.406(4)

Ti2–N8 2.236(5)

–

Ti–Cl

Ti1–Cl1 2.360(2)

Ti1–Cl2 2.333(2)

Ti1–Cl1 2.3592(12)

Ti1–Cl2 2.3755(11)

Ti–N_NHMe

or Ti–N_Py

2.226(6)

Ti1–N1 2.254(3)

2

Ti–O

Ti1–O1Ј 2.240(5)

–

2.889(3)

Ti1–N1–C1 143.9(5)

Ti1Ј–N1–C1 119.2(5)

Ti1–O1 2.177(3)

–

2.8502(13)

Ti1–N1–C10 118.1(3)

Ti1Ј–N1–C10 145.6(3)

–

H_NHMe···Cl

2.638

2.8239(14)

–

2

Ti···Ti

13.33

Ti–N_imido–C_ipso

C1–N1–Ti1 130.2(3)

C1–N1–Ti2 133.0(3)

C9–N2–Ti1 132.4(3)

C9–N2–Ti2 132.0(3)

Cl1–Ti1–Cl2 114.10(7)

Cl3–Ti2–Cl4 95.91(6)

Ti1–N1–C16 174.6(4)

Ti2–N5–C27 178.1(4)

Cl–Ti–Cl

90.34(9)

90.69(4)

Cl1–Ti1–Cl2 163.93(7)

Cl3–Ti2–Cl4 166.35(6)

N1–Ti1–Cl1 98.51(15)

N1–Ti1–Cl2 97.32(15)

N5–Ti1–Cl3 95.76(16)

N5–Ti2–Cl4 97.89(16)

N1–Ti1–N3 177.00(19)

N5–Ti2–N7 178.20(18)

N2–Ti1–N4 166.03(17)

N6–Ti2–N8 165.37(16)

N_imido–Ti–Cl

N1–Ti–Cl1 98.3(2)

N1–Ti–Cl2 109.7(2)

N1–Ti–Cl1 169.36(11)

N1–Ti–Cl2 94.52(9)

misc.

N1–Ti1–O1Ј 157.7(2)

N1–Ti1Ј–O1 74.8(2)

Ti1–N1–Ti1Ј 96.9(3)

N1–Ti1–N1Ј 83.1(3)

N1–Ti1–O1 76.25(12)

N1Ј–Ti1–O1 159.71(12)

Ti1–N1–Ti1Ј 95.92(14)

N1–Ti1–N1Ј 84.08(14)

N–H···Cl 147.64

N3–Ti2–N4 163.95(16)

Ti1–N1–Ti2 96.41(19)

Ti1–N2–Ti2 95.57(19)

N1–Ti1–N2 87.56(18)

N1–Ti2–N2 80.10(17)

Eur. J. Inorg. Chem. 2006, 4503–4518

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4509

C. Lorber, R. Choukroun, L. Vendier

FULL PAPER

Following our one-pot procedure, the chiral amine (S)-

Note that when less than 1 equiv. of chiral benzylic

(–)-α-methylbenzylamine was treated with Ti(NMe₂)₄in the amine is used, we have observed by ¹H NMR spectroscopy

presence of excess Me₃SiCl, and the resulting yellow com- the concomitant formation of another imido species 6* as

plex [Ti{=N-[(S)-(–)-CHMePh]}Cl₂(NHMe₂)₂] (1s*) was a minor side product. The lower solubility of 6* allowed us

obtained in good yields (74%) (Figure 11). By the treatment to selectively obtain a few crystals and to determine its so-

with pyridine, 1s* was transformed into the tris-pyridine lid-state structure. 6s* crystallized in the tetragonal space

adduct [Ti{=N-[(S)-(–)-CHMePh]}Cl₂(Py)₃] (2s*). These group P4₂. The molecular structure is presented in Fig-

complexes represent the first examples of a chiral imido ure 13 and selected distances and angles are summarized in

group on titanium complexes.^[35]

Table 2. Compound 6* is an imido-bridged dimer formu-

lated as [Cl₂Ti{µ-N-[(S)-(–)-CHMePh]}₂TiCl₂(NHMe₂)₂]

that consists of one four- and one six-coordinate titanium

center.^[37]Molecules of 6* possess approximately tetrahe-

dral (Ti1) and octahedral (Ti2) metals linked by bridging

aryl–imido ligands. The Ti–Cl [average Ti1–Cl 2.25 Å,

average Ti2–Cl 2.35 Å] and Ti–N_imido[Ti1–N1 1.821(4) Å,

Ti1–N2 1.840(4) Å, Ti2–N1 1.965(4) Å, Ti2–N2 1.971(4) Å]

distances for Ti2 are longer than those for Ti1 by ca. 0.1 Å

(Ti–Cl) and ca. 0.13 Å (Ti–N_imido), which is consistent with

the higher coordination number of Ti2. The torsion angle

Ti1–N1–Ti2–N2 of the Ti₂N₂core is 4.5(2)°.

Figure 11. Chiral imido–titanium(IV) complexes.

Single-crystals of 1s* (yellow blocks) were obtained from

a toluene/pentane solution at room temp., and the crystal

structure was determined. Complex 1s* crystallized in the

monoclinic space group P2₁.^[36]A thermal ellipsoid plot is

presented in Figure 12 along with selected bond lengths and

angles in Table 1. In the solid state, the molecular structure

of 1s* resembles that of other five-coordinate M(=NR)-

Cl₂(NHMe₂)₂complexes described in this article and by

others (M = Ti,^[26]V^[21]), and the metric parameters are

comparable [avg. N_imido–Ti–Cl 109.9°, avg. N_imido–Ti–

N_NHMe99.8, Ti–N_imidodistance of 1.682(4) Å, Ti–N_imido

–

C1 ang²le = 168.8(4)°, Cl–Ti–Cl angle of 140.12(6)°, mean

Ti–Cl bond lengths of 2.350 Å, Ti–N_aminebond lengths of

avg. 2.205 Å]. In this case, the geometry around the metal

center is closer to square planar (τ = 0.34).

Figure 13. Molecular structure of 6* with selected bond lengths [Å]

and angles [°], which shows 50% probability ellipsoids and partial

atom-labeling schemes. Hydrogen atoms are omitted for clarity.

Similarly, we have attempted the synthesis of the related

imido complex [Ti{=N-[(–)-cis-myrtanyl]}Cl₂(NHMe₂)₂]

(1t*) that has a cis-myrtanyl function (Figure 11). However,

we have not been able to isolate 1t* in a pure form – the

resulting orange material probably contains a mixture of

imido compounds with a lower number of dimethylamine

coligands as judged by its poor solubility and by the low

N-content determined by combustion analysis (unfortu-

1

nately the H NMR spectrum was extremely broad and a

full assignment of the signals was not possible). Neverthe-

less, a subsequent addition of pyridine afforded the desired

pyridine complex [Ti{=N-[(–)-cis-myrtanyl]}Cl₂(Py)₃] (2t*)

as the unique product.^[38]

Interestingly, as an extension, our procedure may be used

to generate multimetallic architectures held together by

imido functions.^[39]For instance, diimido complexes have

Figure 12. Molecular structure of 1s* with selected bond lengths

[Å] and angles [°], which shows 50% probability ellipsoids and par-

tial atom-labeling schemes. Hydrogen atoms are omitted for clarity. been obtained directly from diamines. The reaction of

4510 Eur. J. Inorg. Chem. 2006, 4503–4518

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A General and Facile One-Step Synthesis of Imido–Titanium(IV) Complexes

FULL PAPER

3,3Ј,5,5Ј-tetramethyl[1,1Ј-biphenyl]-4,4Ј-diamine

(H₂N– method for the preparation of imido complexes when N-

BP–NH₂) with 2 equiv. of Ti(NMe₂)₄in the presence of an donor coligands (NHMe₂) are not wanted. The scope of

excess of Me₃SiCl afforded the binuclear derivative this synthesis will be developed elsewhere.

[(Me₂HN)₂Cl₂Ti(=N–BP–N=)TiCl₂(NHMe₂)₂] (7, Fig-

ure 14). Replacement of the dimethylamine ligands was

prompted by the addition of pyridine to 7 and afforded the

pyridine analogue [(Py)₃Cl₂Ti(=N–BP–N=)TiCl₂(Py)₃] (8).

An X-ray structure determination of a crystal of 8 (Fig-

ure 15 and Table 2) reveals a binuclear titanium complex

with a bridging spacer composed of the diimido unit. The

Scheme 3. Alternative synthesis of imido–titanium(IV) compounds.

Conclusions

two titanium centers have an octahedral geometry with

structure, bond lengths, and angles similar to the monome-

tallic species. The titanium–nitrogen bond length of the

imido fragments are 1.719(4) Å and 1.710(4) Å, the imido

fragment were found to be almost linear [Ti–N_imido–C_ipso

174.6(4)° and 178.1(4)°], and Ti–Cl bond lengths are in the

range 2.39–2.42 Å. The dihedral angle between the planes

of the two benzene rings of the biphenyl unit is 14.0(2)°.

We have reported a direct and efficient method to gener-

ate titanium(IV) complexes of the type Ti(=NR)-

Cl₂(NHMe₂)₂from commercially available Ti(NMe₂)₄and

a wide range of primary amines under simple and mild con-

ditions. We have also demonstrated the functional group

tolerance of this reaction, and it has been applied to the

synthesis of titanium complexes that have an additional

functionality on the imido moiety. The reactivity of these

functionalized imido groups can now be ascertained and

the added functionality may also serve as an anchor to graft

this species onto a support. Also of great interest, we have

been able to prepare complexes with diimido ligands, as

well as the first Ti compounds that contain chiral imido

supporting ligands. As an alternative method, we have re-

ported some preliminary results on the synthesis of imido–

titanium complexes of the type [Ti(NAr)I₂(thf)₂]₂that use

CH₃I as a reagent.

Figure 14. Diimido-titanium(IV) complex 7.

4. Alternative Synthesis of Imido–Titanium Species

Experimental Section

The reaction of Ti(NMe₂)₄with 2,6-iPr₂–C₆H₃NH₂in

THF with an excess of CH₃I in place of chlorotrimethylsil- General Methods and Instrumentation: All manipulations were car-

ried out with a standard Schlenk line or dry box techniques under

an atmosphere of argon. Solvents were refluxed and dried with

the appropriate drying agents under an atmosphere of argon, and

collected by distillation. NMR spectra were recorded with a Bruker

AM200, AM250, ARX250, DPX300, or Avance500 spectrometers,

referenced internally to residual protio-solvent (¹H) resonances,

and are reported relative to tetramethylsilane (δ = 0 ppm). ¹⁹F

NMR spectra were recorded with a Bruker AM200 spectrometer

(reference CF₃CO₂H). ²⁹Si NMR spectra were recorded with a

Bruker Avance500 spectrometer. Infrared spectra were prepared

ane can be used to generate an aryl–imido complex. This

reaction proceeds at room temperature (Scheme 3), with al-

kylation of the four dimethylamido groups.^[40]After fil-

tration of the insoluble Me₄NI salt, the imido complex for-

mulated as [Ti(NAr)I₂(thf)₂] (9) (Ar = 2,6-iPr₂–C₆H₃), as

1

judged by H NMR spectroscopy and combustion analysis,

is obtained in 79% yield. This compound is most probably

a dimer with bridging iodides as in the structurally estab-

lished phenylimido analogue [Ti(=NPh)Cl(µ-Cl)(thf)₂]₂.^[4c]

This new synthesis could be important as an alternative under an argon atmosphere in a glove box and were recorded with

Figure 15. Molecular structure of 8 with selected bond lengths [Å] and angles [°], which shows 50% probability ellipsoids and partial

atom-labeling schemes. Hydrogen atoms are omitted for clarity.

Eur. J. Inorg. Chem. 2006, 4503–4518

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4511

C. Lorber, R. Choukroun, L. Vendier

FULL PAPER

a Perkin–Elmer Spectrum GX FT-IR spectrometer. Elemental

analyses were performed at the Laboratoire de Chimie de Coordi-

nation (Toulouse, France) (C, H, N) or by the Service Central de

Microanalyses du CNRS at Vernaison (France) (C, H, N, Cl).

97^[43]integrated in the package WINGX version 1.64;^[44]empirical

absorption corrections were applied on the data.^[45]All hydrogen

atoms have been located on differences Fourier maps, and intro-

duced into the refinement as fixed contributors with a riding model

with an isotropic thermal parameter fixed at 20% higher than those

of the Csp²atoms and 50% for the Csp³atoms to which they were

connected. The methyl groups were refined with the torsion angle

as a free variable. Some exceptions for a few specific hydrogen

atoms were made, which have been isotropically refined (like nitro-

gen bound hydrogens). For the seven structures all non-hydrogen

atoms were anisotropically refined, and in the last cycles of the

refinement weighting schemes were used, where weights are calcu-

lated from the following formula: w = 1/[σ²(F_o²)+(aP)²+bP] where

The Ti(NMe₂)₄used in this study was prepared by a modification

of a literature procedure,^[41]or purchased from commercial sources

(Aldrich, Acros). Liquid anilines and amines were dried with KOH

or CaH₂, refluxed, distilled, and stored over 4 Å molecular sieves

under an argon atmosphere before use. Trimethylchlorosilane was

distilled and stored over 4 Å molecular sieves under an argon atmo-

sphere before use. The optical purity of the enantiomerically pure

chiral amines used in this study [(S)-(–)-α-methylbenzylamine and

(–)-cis-myrtanylamine] was 98% (Aldrich).

2

P = (F_o²+2F_c)/3. The poor quality of the structure determination

of 3 is due to the small size of the crystal, and was not sufficient

to give precise bond lengths and angles. For 8 it was not possible

to resolve diffuse electron-density residuals (enclosed solvent mole-

cules). Treatment with the SQUEEZE facility from PLATON,^[46]

with a localized void of about 1730 Å³and 75 recovered electrons,

resulted in a smooth refinement. Since a few low-order reflections

are missing from the data set, the electron count will be underesti-

mated. Thus, the values given for D_calc, F(000) and the molecular

weight are only valid for the ordered part of the structure. For 1s*,

the Flack parameter^[47]was refined to a value of 0.11(7). Although,

the standard deviation on this parameter is rather high, inversion

of the configuration gave a value of 0.89, and so the absolute con-

figuration could be determined and it agrees with the synthetic

pathway [in addition, the Flack parameter for complex 6*, which

is derived from 1s*, was refined to a satisfying value of 0.04(3)].

The deviation of the Flack parameter from 0 is probably due to

the weak anomalous diffusion of Ti and Cl atoms. CCDC-608174

to -608184 contain the supplementary crystallographic data

for this paper. These data can be obtained free of charge

from The Cambridge Crystallographic Data Centre via

www.ccdc.cam.ac.uk/data_request/cif.

Crystal Structure Determination: Crystals of 1k (dark-green

blocks), 1o (orange plates), 1p (orange plates), 1s* (yellow blocks),

2d (yellow blocks), 2l (orange plates), 2r (orange parallelepipeds),

3 (dark-red blocks), 5 (orange blocks), 6* (green plates), and 8

(orange blocks) were obtained. Crystal data collection and pro-

cessing parameters are given in Table 3 and Table 4. The selected

crystals, sensitive to air and moisture, were mounted on a glass

fiber with perfluoropolyether oil and cooled rapidly to 180 K in a

stream of cold N₂. Data were collected at low temperature (T =

180 K) with a Stoe Imaging Plate Diffraction System (IPDS)

equipped with an Oxford Cryosystems Cryostream Cooler Device

or an Oxford Diffraction Kappa CCD Excalibur diffractometer

equipped with an Oxford Instrument cryojet, with graphite-mono-

chromated Mo-K_αradiation (λ = 0.71073 Å). Final unit cell param-

eters were obtained by means of a least-squares refinement of a set

of 8000 well-measured reflections, and crystal decay was monitored

during data collection by the measurement of 200 reflections by

image; no significant fluctuation of intensities has been observed.

Structures have been solved by means of Direct Methods with the

program SIR92,^[42]and subsequent difference Fourier maps. Mod-

els were refined by least-squares procedures on a F²with SHELXL-

Table 3. Crystallographic data, data collection and refinement parameters for compounds 1k, 1p, 1o, 1s*, 2d, and 2l.

1k

1o

1p

1s*^[a]

2d

2l

Chemical formula

C₁₄H₂₈Cl₂N₄Ti

371.20

C₁₃H₂₃Cl₂N₃Ti

340.14

monoclinic

P2₁/c

13.9252(7)

10.2394(5)

12.1777(6)

90.0

89.897(4)

90.0

1736.36(15)

4

1.301

0.792

712

C₁₂H₁₉Cl₂N₃Ti

324.10

monoclinic

P2₁/a

8.9189(7)

20.246(2)

9.1104(8)

90.0

98.747(10)

90.0

1626.0(2)

4

1.324

0.842

672

C₁₂H₂₃Cl₂N₃Ti

328.10

monoclinic

P2₁

9.0267(9)

10.5665(18)

9.0580(12)

90.0

103.210(10)

90.0

841.1(2)

2

1.296

0.815

344

C₃₃H₃₀Cl₂N₄SiTi C₂₂H₁₉Cl₂N₅Ti

Formula weight

Crystal system

Space group

a [Å]

b [Å]

c [Å]

629.50

472.22

triclinic

monoclinic

P2₁/c

monoclinic

C2/c

¯

P1

9.182(5)

9.694(5)

12.436(5)

107.181(5)

109.035(5)

94.289(5)

981.6(8)

2

10.8267(5)

11.2667(5)

26.8863(14)

90.0

8.2536(6)

23.3710(11)

12.5545(6)

90.0

α [°]

β [°]

107.819(4)

90.0

105.544(5)

90.0

γ [°]

V( [Å]³)

Z

3122.3(3)

4

2333.1(2)

4

D_calc(gcm^–3

)

1.256

0.708

392

1.339

1.344

µ (Mo-K_α) [mm^–1

F(000)

]

0.513

0.614

1304

968

θ range [°]

3.51–32.06

10407

6192/0.0223

196/0

3.54–32.15

17009

5707/0.0277

183/3

2.48–25.68

12282

3070/0.0549

166/1

2.87–32.04

8603

3962/0.0746

169/1

2.96–32.26

26117

10210/0.0209

370/0

3.49–25.68

7813

2215/0.0242

140/0

Measured reflections

Unique reflections/Rint

Parameters/restraints

Final R indices [IϾσ2(I)] R₁= 0.0424

wR₂= 0.1131

R₁= 0.0338

wR₂= 0.0819

R₁= 0.0497

wR₂= 0.0873

1.067

R₁= 0.0509

wR₂= 0.1082

R₁= 0.0583

wR₂= 0.1106

1.167

R₁= 0.0552

wR₂= 0.1067

R₁= 0.1065

wR₂= 0.1383

0.841

R₁= 0.0452

wR₂= 0.1080

R₁= 0.0578

wR₂= 0.01157

1.070

R₁= 00.0304

wR₂= 0.0703

R₁= 0.0346

wR₂= 0.0731

1.051

Final R indices all data

R₁= 0.0516

wR₂= 0.1170

1.077

Goodness of fit

∆ρmax and ∆ρmin

0.905 and –0.514 0.531 and –0.311 0.349 and –0.305 0.360 and –0.407 0.462 and –0.529 0.264 and –0.210

[a] Absolute structure parameter: 0.11(7).

4512

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Eur. J. Inorg. Chem. 2006, 4503–4518

A General and Facile One-Step Synthesis of Imido–Titanium(IV) Complexes

FULL PAPER

Table 4. Crystallographic data, data collection and refinement parameters for compounds 2r, 3, 5, 6*, and 8.

2r

3

5

6*^[a]

C₂₀H₃₂Cl₄N₄O₂Ti₂C₂₀H₂₈Cl₄N₄O₂Ti₂C₂₀H₃₂Cl₄N₄Ti₂

8

Chemical formula

C₂₃H₂₆Cl₂N₄Ti,

C₅H₅N

C₄₆H₄₆Cl₄N₈Ti₂

Formula weight

Crystal system

Space group

a [Å]

b [Å]

c [Å]

556.38

598.04

monoclinic

P2₁/n

9.868(2)

7.9255(16)

16.575(3)

90.0

90.77(3)

90.0

1296.2(4)

2

1.532

1.053

616

594.06

monoclinic

P2₁/n

10.1969(15)

11.9115(13)

11.0227(15)

90.0

112.931(15)

90.0

1233.0(3)

2

1.600

1.107

608

566.10

tetragonal

P4₂

13.043(2)

15.073(3)

90.0

2564.2(8)

4

1.466

948.51

monoclinic

P2₁/n

15.7668(12)

17.2900(12)

21.7813(19)

90.0

96.202(7)

90.0

5903.0(8)

4

1.067

0.484

1960

monoclinic

¯

P1

9.1233(9)

10.3422(11)

15.5338(13)

76.531(8)

80.338(8)

87.611(9)

1405.2(2)

2

α [°]

β [°]

γ [°]

V( [Å]³)

Z

D_calc(gcm^–3)

µ (Mo-K_α) [mm^–1]

F(000)

1.315

0.520

580

1.055

1168

θ range [°]

Measured reflections

Unique reflections/Rint

Parameters/restraints

Final R indices [IϾσ2(I)] R₁= 0.0372

wR₂= 0.0923

2.73–32.05

14916

8919/0.0312

325/0

3.30–23.25

7332

1854/0.1297

148/0

R₁= 0.0996

wR₂= 0.2462

R₁= 0.1203

wR₂= 0.2684

1.058

2.64–25.68

9348

2332/0.1180

145/0

R₁= 0.0432

wR₂= 0.0951

R₁= 0.0853

wR₂= 0.1051

0.851

3.12–24.69

17232

4373/0.1019

277/1

R₁= 0.0431

wR₂= 0.0549

R₁= 0.0765

wR₂= 0.0622

0.784

3.02–26.37

41980

12047/0.1418

545/0

R₁= 0.0950

wR₂= 0.2361

R₁= 0.1510

wR₂= 0.2649

0.993

Final R indices all data

R₁= 0.0544

wR₂= 0.1045

0.958

Goodness of fit

∆ρmax and ∆ρmin

0.488 and –0.586

1.322 and –1.089

0.308 and –0.321

0.274 and –0.254

0.634 and –0.792

[a] Absolute structure parameter 0.04(3).

[Ti(=NR)Cl₂(NHMe₂)₂] (1a–t). General Synthetic Procedure: To a

toluene solution (5 mL) of Ti(NMe₂)₄(250 mg, 1.115 mmol),

amine RNH₂(1 equiv. 1.115 mmol) was added at room tempera-

ture. To this solution Me₃SiCl (1.00 g) was slowly added at room

temperature. The resulting solution was stirred overnight at room

temp. (or at 60 °C for 1a, for the other compounds we did not

notice significant changes in yields when the reaction was per-

formed at 60 °C). Depending on the amine RNH₂used, the prod-

uct separates from the solution as a crystalline compound (without

or upon the addition of pentane), or the volatiles were removed

under reduced pressure. The yellow–orange microcrystalline solid

was then washed with pentane (2×10 mL), and dried under vac-

uum to afford the analytically and spectroscopically pure material.

Pure 1 was obtained by recrystallization from toluene/pentane.

Yields are calculated on the basis of 250-mg scale reaction of

Ti(NMe₂)₄. Some of these compounds have been prepared with up

to 2 g of Ti(NMe₂)₄with similar yields.

[Ti(=N–CPh₃)Cl₂(NHMe₂)₂] (1c): Yield 475 mg (91%) (yellow). ¹H

NMR (250 MHz, CD₂Cl₂): δ = 7.21–7.38 (m, 15 H, C₆H₅), 3.27

(br. sept, 2 H, NH), 2.44 (d, ³J = 6.1 Hz, 12 H, NHMe₂) ppm.

¹³C{¹H} NMR (62.90 MHz, CD₂Cl₂): δ = 147.7, 129.0, 128.0,

126.9 (C₆H₅, one signal not observed), 40.7 (NHMe₂) ppm. IR

(KBr): ν = 3233 (m, NH), 2929 (m), 2780 (m), 1596 (m), 1467 (m),

˜

1443 (m), 1209 (m), 1020 (m), 991 (w), 893 (m), 755 (m), 699 (s),

636 (m), 420 (m) cm^–1. C₂₃H₂₉Cl₂N₃Ti (466.27): calcd. C 59.25, H

6.27, N 9.01; found: C 59.07, H 6.24, N 8.87.

[Ti(=N–SiPh₃)Cl₂(NHMe₂)₂] (1d): Yield 490 mg (91%) (yellow). ¹H

NMR (250 MHz, CD₂Cl₂): δ = 7.72 (m, 6 H, C₆H₅), 7.38 (m, 9 H,

C₆H₅), 3.39 (br. sept, 2 H, NH), 2.55 (d, ³J = 6.2 Hz, 12 H,

NHMe₂) ppm. ¹³C{¹H} NMR (125.81 MHz, CD₂Cl₂): δ = 136.9,

135.5, 130.6, 129.7 (C₆H₅), 41.2 (NHMe₂) ppm. ²⁹Si NMR

(99.40 MHz, CD Cl ): δ = –43 ppm. IR (KBr): ν = 3242 (s, NH),

˜

2

1465 (m), 1427 (m), 1111 (vs), 893 (w), 703 (s), 507 (s) cm^–1.

C₂₂H₂₉Cl₂N₃SiTi (482.34): calcd. C 54.78, H 6.06, N 8.71; found

C 54.66, H 6.07, N 8.66.

[Ti(=N–tBu)Cl₂(NHMe₂)₂] (1a): Yield 260 mg (93%) (yellow). ¹H

3

NMR (250 MHz, CD₂Cl₂): δ = 3.46 (br. m, 2 H, NH), 2.71 (d, J

= 6.2 Hz, 12 H, NHMe₂), 1.05 (s, 9 H, tBu) ppm. ¹³C{¹H} NMR

(62.90 MHz, CD₂Cl₂): δ = 73.6 (CMe₃), 41.1 (NHMe₂), 31.5

[Ti(=N–Ph)Cl₂(NHMe₂)₂] (1e): Yield 273 mg (81%) (red–orange).

¹H NMR (250 MHz, CD₂Cl₂): δ = 7.07 (t, 2 H, C₆H₅), 6.82 (m, 3

H, C₆H₅), 3.56 (br. sept, 2 H, NH), 2.76 (d, ³J = 6.2 Hz, 12 H,

NHMe₂) ppm. C₁₀H₁₉Cl₂N₃Ti (300.05): calcd. C 40.03, H 6.38, N

14.00; found C 39.86, H 6.41, N 13.92.

(CMe ) ppm. IR (KBr): ν = 3234 (s, NH), 2973 (s), 1517 (m), 1363

˜

3

(w), 1244 (m), 1184 (m), 1090 (m), 1015 (s), 975 (s), 901 (m), 810

(w), 557 (m), 498 (w) cm^–1. C₈H₂₃Cl₂N₃Ti (280.06): calcd. C 34.31,

H 8.28, N 15.00; found C 34.33, H 8.35, N 14.86.

[Ti(=N–2,6-iPr₂–C₆H₃)Cl₂(NHMe₂)₂] (1f): Yield 410 mg (96%)

1

3

[Ti(=N–1-Adamantane)Cl₂(NHMe₂)₂] (1b): Yield 320 mg (80%)

(orange). H NMR (300 MHz, C₆D₆): δ = 6.99 (d, J = 7.5 Hz, 2

(yellow). ¹H NMR (300 MHz, CD₂Cl₂): δ = 3.48 (br. m, 2 H, NH),

H, C₆H₃), 6.85 (t, ³J = 7.6 Hz, 1 H, C₆H₃), 4.67 (sept, ³J = 6.7 Hz,

3

2.71 (d, J = 6.0 Hz, 12 H, NHMe₂), 1.89 (br. s, 3 H, CH_ada), 1.66 2 H, CHMe₂), 2.91 (br. m, 2 H, NH), 2.27 (d, J = 6.3 Hz, 12 H,

(br. s, 6 H, CH_2ada), 1.48 (br. s, 6 H, CH_2ada) ppm. ¹³C{¹H} NMR

(75.47 MHz, CD₂Cl₂): δ = 75.4 (C_q), 45.4 (C_q), 41.2 (NHMe₂), 36.5 (75.47 MHz, C₆D₆): δ = 157.8, 144.7, 123.8, 122.7 (C₆H₃), 40.8

(C_ada), 30.1 (C_ada) ppm. IR (KBr): ν = 3233 (w, NH), 2921 (vs), (NHMe ), 28.0 (CHMe ), 24.6 (CHMe ) ppm. IR (KBr): ν = 3255

NHMe₂), 1.44 (d, ³J = 6.9 Hz, 12 H, CHMe₂) ppm. ¹³C{¹H} NMR

˜

2

1465 (m), 1365 (m), 1237 (s), 1097 (m), 1016 (m), 894 (s), 499 (w) (w, NH), 2961 (m), 1465 (s), 1334 (s), 1288 (s), 1021 (m), 896 (m),

cm^–1. C₁₄H₂₉Cl₂N₃Ti (358.17): calcd. C 46.95, H 8.16, N 11.73; 753 (s), 668 (vs) cm^–1. C₁₆H₃₁Cl₂N₃Ti (384.21): calcd. C 50.02, H

found C 47.05, H 8.19, N 11.60.

8.13, N 10.94; found C 49.93, H 8.20, N 10.81.

Eur. J. Inorg. Chem. 2006, 4503–4518

www.eurjic.org

4513

C. Lorber, R. Choukroun, L. Vendier

FULL PAPER

[Ti(=N–2,6-Cl₂–C₆H₃)Cl₂(NHMe₂)₂] (1g): Yield 300 mg (73%)

¹³C{¹H} NMR (62.90 MHz, CD₂Cl₂): δ = 160.5, 133.3, 131.9,

1

3

(orange). H NMR (250 MHz, C₆D₆): δ = 6.90 (d, J = 8.0 Hz, 2

129.2, 128.3, 123.8, 122.0, 41.3 (NHMe ) ppm. IR (KBr): ν = 3228

˜

2

3

H, C₆H₃), 6.13 (t, J = 7.9 Hz, 1 H, C₆H₃), 2.97 (br. m, 2 H, NH),

(m, NH), 2971 (w), 2934 (w), 2242 (s, CN), 1570 (s), 1462 (s), 1446

(s), 1350 (s), 1262 (m), 1018 (m), 995 (m), 973 (w), 898 (m), 765 (s)

cm^–1. C₁₁H₁₈Cl₂N₄Ti (325.06): calcd. C 40.64, H 5.58, N 17.24;

found C 40.37, H 5.44, N 17.06.

2.28 (d, ³J = 6.2 Hz, 12 H, NHMe₂) ppm. ¹³C{¹H} NMR

(62.90 MHz, C₆D₆): δ = 158.0, 130.6, 122.2 (C₆H₃, one signal not

observed, probably obscured under C₆D₆), 41.2 (NHMe₂) ppm. IR

(KBr): ν = 3251 (s, NH), 2977 (m), 2931 (m), 2783 (m), 1610 (w),

˜

[Ti(=N–4-H₂C=CH–C₆H₄)Cl₂(NHMe₂)₂] (1n): Yield 240 mg (74%)

1468 (m), 1434 (vs), 1397 (m), 1332 (s), 1258 (w), 1192 (w), 1071

(w), 1011 (s), 983 (m), 894 (s), 788 (s), 759 (m), 718 (m), 568 (m),

458 (w), 425 (w) cm^–1. C₁₀H₁₇Cl₄N₃Ti (368.94): calcd. C 32.55, H

4.64, N 11.39; found C 32.53, H 4.60, N 11.25.

1

3

(red). H NMR (250 MHz, C₆D₆): δ = 7.15 (d, J = 8.3 Hz, 2 H,

C₆H₄), 6.96 (d, ³J = 8.3 Hz, 2 H, C₆H₄), 5.57 (dd, J = 17.6 and

3

11.8 Hz, 1 H, =CH), 5.53 (d, J = 18.5 Hz, 1 H, =CH), 5.02 (d, J

3

= 12.0 Hz, 1 H, =CH), 2.62 (m, 2 H, NH), 2.25 (d, J = 6.1 Hz,

12 H, NHMe₂) ppm. ¹³C{¹H} NMR (62.90 MHz, C₆D₆): δ = 161.5

(C₆H₄), 137.2 (=CH), 132.6, 127.0, 124.5 (C₆H₄), 112.7 (=CH₂),

[Ti(=N–2,6-Br₂–4-Me–C₆H₂)Cl₂(NHMe₂)₂] (1h): Yield 451 mg

(96%) (orange). ¹H NMR (250 MHz, C₆D₆): δ = 6.97 (d, 2 H,

C₆H₂), 3.17 (br. m, 2 H, NH), 2.36 (d, ³J = 6.1 Hz, 12 H, NHMe₂),

1.69 (s, 3 H, Me_Ar) ppm. ¹³C{¹H} NMR (62.90 MHz, C₆D₆): δ =

152.7, 133.7, 132.4, 120.5 (C₆H₂), 41.4 (NHMe₂), 20.2 (Me_Ar) ppm.

41.0 (NHMe ) ppm. IR (KBr): ν = 3266 (m, NH), 3237 (m, NH),

˜

2

2973 (m), 2935 (m), 1624 (w, C=C), 1588 (w), 1491 (s), 1466 (s),

1400 (w), 1326 (s), 1264 (m), 1114 (m), 1018 (s), 893 (s), 842 (s),

609 (w) cm^–1. C₁₂H₂₁Cl₂N₃Ti (326.09): calcd. C 44.20, H 6.49, N

12.89; found C 44.10, H 6.50, N 12.54.

IR (KBr): ν = 3248 (s, NH), 3008 (w), 2975 (w), 2937 (w), 2781

˜

(w), 1465 (m), 1442 (s), 1332 (s), 1255 (w), 1011 (s), 896 (s), 850

(m), 741 (s), 713 (m), 581 (m), 568 (m), 459 (w), 423 (w) cm^–1.

C₁₁H₁₉Br₂Cl₂N₃Ti (471.87): calcd. C 28.00, H 4.06, N 8.91; found

C 28.05, H 4.08, N 8.89.

[Ti(=N–2-MeC=CH₂–C₆H₄)Cl₂(NHMe₂)₂] (1o): Yield 250 mg

(73%) (red). ¹H NMR (250 MHz, C₆D₆): δ = 7.31 (dd, ³J = 9.0 Hz,

1 H, C₆H₄), 7.07 (dd, ³J = 7.6 Hz, 1 H, C₆H₄), 7.00 (td, ³J = 9.6 Hz,

3

1

1 H, C₆H₄), 6.74 (t, J = 7.4 Hz, 1 H, C₆H₄), 5.26 (app d, app. J

[Ti(=N–C₆F₅)Cl₂(NHMe₂)₂] (1i): Yield 405 mg (93%) (orange). H

3

= 12.9 Hz, 2 H, CH₂), 2.77 (br. m, 2 H, NH), 2.52 (s, 3 H, CH₃),

2.26 (d, ³J = 6.3 Hz, 12 H, NHMe₂) ppm. ¹³C{¹H} NMR

(62.90 MHz, C₆D₆): δ = 158.8, 147.2, 136.0 (C₆H₄, 1 peak obscured

under C₆D₆), 123.2 (C=CH₂), 115.2 (C=CH₂), 41.0 (NHMe₂), 25.0

NMR (250 MHz, C₆D₆): δ = 2.70 (br. m, 2 H, NH), 2.21 (d, J =

6.1 Hz, 12 H, NHMe₂) ppm. ¹⁹F NMR (C₆D₆, 188.3 MHz): δ =

–78.8 (d, 2F, o-C₆F₅), –89.5 (t, 2F, m-C₆F₅), –90.3 (t, 1F, p-C₆F₅)

ppm. C₁₀H₁₄Cl₂F₅N₃Ti (390.00): calcd. C 30.80, H 3.62, N 10.77;

found C 30.75, H 3.57, N 10.70.

(CH ) ppm. IR (KBr): ν = 3226 (m, NH), 2973 (w), 2934 (w), 1629

˜

3

(w, C=C), 1517 (w), 1466 (s), 1430 (s), 1322 (s), 1115 (w), 1094 (w),

1020 (m), 997 (w), 973 (w), 982 (w), 894 (m), 750 (m), 573 (w), 472

(w) cm^–1. C₁₃H₂₃Cl₂N₃Ti (340.11): calcd. C 45.91, H 6.82, N 12.35;

found C 45.83, H 6.98, N 11.91.

[Ti[=N–3,5-(F₃C)₂–C₆H₃]Cl₂(NHMe₂)₂] (1j): Yield 380 mg (87%)

(red–orange). ¹H NMR (250 MHz, C₆D₆): δ = 7.36 (br. s, 3 H,

C₆H₃), 2.36 (br. m, 2 H, NH), 2.11 (d, ³J = 6.0 Hz, 12 H, NHMe₂)

ppm. ¹³C{¹H} NMR (62.90 MHz, C₆D₆): δ = 159.1, 132.7, 124.3,

123.7 (C₆H₃), 115.4 (CF₃), 41.0 (NHMe₂) ppm. ¹⁹F NMR

[Ti(=N–3-HCϵC–C₆H₄)Cl₂(NHMe₂)₂] (1p): Yield 260 mg (72%)

3

(red). ¹H NMR (500 MHz, CD₂Cl₂): δ = 7.07 (t, J = 8.0 Hz, 1 H,

(188.3 MHz, C D ): δ = 13.31 ppm. IR (KBr): ν = 3229 (m, NH),

˜

6

3

C₆H₄), 6.99 (s, 1 H, C₆H₄), 6.98 (d, J = 8.5 Hz, 1 H, C₆H₄), 6.85

3008 (w), 2982 (w), 1598 (w), 1466 (m), 1460 (m), 1387 (s), 1278

(vs), 1177 (s), 1132 (vs), 1040 (s), 1022 (m), 894 (m), 876 (m), 682

(m), 426 (w) cm^–1. C₁₂H₁₇Cl₂F₆N₃Ti (436.05): calcd. C 33.05, H

3.93, N 9.64; found C 33.03, H 3.94, N 9.51.

3

(d, J = 8.6 Hz, 1 H, C₆H₄), 3.60 (br. m, 2 H, NH), 3.11 (s, 1 H,

3

ϵCH), 2.78 (d, J = 6.1 Hz, 12 H, NHMe₂) ppm. ¹³C{¹H} NMR

(125.81 MHz, CD₂Cl₂): δ = 159.6, 128.4, 126.7, 126.0, 123.8, 121.9

(C₆H₄), 83.3 (CϵCH), 76.7 (ϵCH), 40.8 (NHMe₂) ppm. IR (KBr):

[Ti(=N–4-Et₂N–C₆H₄)Cl₂(NHMe₂)₂] (1k): Yield 345 mg (93%)

ν = 3270 (m, NH), 3255 (m, NH), 2977 (m), 2208 (w, CϵC), 1577

˜

3

(green). ¹H NMR (250 MHz, C₆D₆): δ = 7.11 (d, J = 8.9 Hz, 2 H,

(w), 1467 (s), 1407 (m), 1329 (s), 1261 (m), 1099 (m), 1025 (s), 993

(s), 794 (s), 676 (m) cm^–1. C₁₂H₁₉Cl₂N₃Ti (324.07): calcd. C 44.47,

H 5.91, N 12.97; found C 45.94, H 6.53, N 11.91. We were unable

to obtain satisfactory elemental analysis for this compound even

on a recrystallized sample (from cold toluene/pentane solutions).

3

C₆H₄), 6.40 (d, J = 9.0 Hz, 2 H, C₆H₄), 2.94 [q, J = 7.0 Hz, 4 H,

3

N(CH₂CH₃)₂], 2.80 (br. m, 2 H, NH), 2.36 (d, J = 6.1 Hz, 12 H,

NHMe₂), 0.86 [t, ³J = 7.0 Hz, 6 H, N(CH₂CH₃)₂] ppm. ¹³C{¹H}

NMR (250 MHz, C₆D₆): δ = 156.2, 144.2, 125.9, 112.7 (C₆H₄), 45.2

[N(CH₂CH₃)₂], 41.2 (NHMe₂), 13.4 [N(CH₂CH₃)₂] ppm. IR (KBr):

1

A H NMR spectrum is provided in the supporting information.

ν = 3249 (s, NH), 2973 (s), 1597 (m), 1499 (vs), 1465 (m), 1320 (m),

˜

[Ti(=N–3-O₂N–6-Me–C₆H₃)Cl₂(NHMe₂)₂] (1q): Yield 270 mg

1265 (vs), 1005 (m), 896 (m), 815 (s), 458 (w) cm^–1. C₁₄H₂₈Cl₂N₄Ti

(371.17): calcd. C 45.30, H 7.60, N 15.09; found C 45.12, H 7.74,

N 14.99.

1

(67%) (brown). H NMR (250 MHz, CD₂Cl₂): δ = 7.70 (s, 1 H, o-

3

C₆H₃), 7.54 (d, J = 8.3 Hz, 1 H, p-C₆H₃), 7.12 (d, J = 8.3 Hz, 1

H, m-C₆H₃), 3.57 (br. m, 2 H, NH), 2.78 (d, ³J = 5.6 Hz, 12 H,

NHMe₂), 2.56 (s,

3

H, C₆H₃Me) ppm. ¹³C{¹H} NMR

[Ti(=N–4-NC–C₆H₄)Cl₂(NHMe₂)₂] (1l): Yield 280 mg (77%)

1

3

(orange). H NMR (250 MHz, CD₂Cl₂): δ = 7.39 (d, J = 8.6 Hz,

(125.81 MHz, CD₂Cl₂): δ = 130.0 (C₆H₃), 40.9 (NHMe₂), 35.4

(C₆H₃Me) ppm (because of poor solubility, not all C₆H₃reso-

2 H, C₆H₄), 6.85 (d, ³J = 8.5 Hz, 2 H, C₆H₄), 3.54 (br. m, 2 H,

3

NH), 2.75 (d, J = 6.3 Hz, 12 H, NHMe₂) ppm. The low solubility

nances are observed). IR (KBr): ν = 3281 (s, NH), 2976 (w), 2934

˜

of 1l precluded its ¹³C{¹H} NMR analysis. IR (KBr): ν = 3214 (m,

˜

(w), 2776 (w), 1517 (vs, NO₂), 1468 (s), 1400 (m), 1353 (vs), 1313

(m), 1250 (w), 1099 (w), 1020 (m), 1002 (m), 894 (s), 844 (m), 740

(m), 640 (w), 420 (w) cm^–1. C₁₂H₂₀Cl₂N₄O₂Ti (359.07): calcd. C

36.79, H 5.61, N 15.60; found C 36.58, H 5.48, N 15.38.

NH), 2978 (w), 2923 (w), 2243 (s, CN), 1586 (s), 1487 (s), 1441 (s),

1168 (m), 1021 (m), 961 (w), 897 (m), 836 (m), 773 (w), 551 (w)

cm^–1. C₁₁H₁₈Cl₂N₄Ti (325.06): calcd. C 40.64, H 5.58, N 17.24;

found C 40.54, H 5.52, N 17.12.

[Ti{=N(C₆H₁₀CϵCH)}Cl₂(NHMe₂)₂] (1r): Yield 220 mg (60%)

1

[Ti(=N–2-NC–C₆H₄)Cl₂(NHMe₂)₂] (1m): Yield 350 mg (96%) (yellow). H NMR (500 MHz, C₆D₆): δ = 2.78 (m, 2 H, NH), 2.36

1

3

(orange). H NMR (250 MHz, CD₂Cl₂): δ = 7.31 (app. t, app. J

(d, J = 6.0 Hz, 12 H, NHMe₂), 2.10 (s, 1 H, ϵCH), 1.91 (br. m,

3

= 8.6 Hz, 2 H, C₆H₄), 6.85 (app. t, app. J = 7.3 Hz, 2 H, C₆H₄),

3.82 (br. m, 2 H, NH), 2.78 (d, J = 5.6 Hz, 12 H, NHMe₂) ppm.

2 H, CH₂), 1.62 (br. m, 2 H, CH₂), 1.54 (br. m, 4 H, CH₂), 1.41

(br. m, 1 H, CH_aH_b), 1.07 (br. m, 1 H, CH_aH_b) ppm. ¹³C{¹H}

3

4514

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Eur. J. Inorg. Chem. 2006, 4503–4518

A General and Facile One-Step Synthesis of Imido–Titanium(IV) Complexes

FULL PAPER

NMR (125.81 MHz, C₆D₆): δ = 88.0 (CϵCH), 73.0 (CN), 71.0 CD₂Cl₂): δ = 152.6 (cis-Py), 152.0 (trans-Py), 138.7 (cis-Py), 136.7

(CϵCH), 41.7 (CH₂), 41.5 (NHMe₂), 26.1 (CH₂), 23.7 (CH₂) ppm. (trans-Py), 123.9 (cis-Py), 123.5 (trans-Py), 87.1 (CϵCH), 71.1

IR (KBr): ν = 3278 (s, ϵCH), 3263, 3248 (m, NH), 2935 (s), 1466

(CN), 69.9 (CϵCH), 39.5 (CH₂), 25.3 (CH₂), 22.6 (CH₂) ppm.

˜

(m), 1342 (m), 1266 (s), 1198 (s), 1005 (s), 895 (s), 668 (m), 655 C₂₃H₂₆Cl₂N₄Ti (477.25): calcd. C 57.88, H 5.49, N 11.74; found C

(m), 600 (w), 537 (w), 487 (w), 419 (w) cm^–1. C₁₂H₂₅Cl₂N₃Ti

(330.12): calcd. C 43.66, H 7.63, N 12.73; found C 43.50, H 7.72,

N 12.34.

57.86, H 5.44, N 11.78.

[Ti{=N–[(S)-(–)-CHMePh]}Cl₂(Py)₃] (2s*): This compound was

obtained from 1s* (250 mg) with a procedure similar to the one

described for 2d. Yield 160 mg (44%) (orange needles). H NMR

1

[Ti{=N–[(S)-(–)-CHMePh]}Cl₂(NHMe₂)₂] (1s*): Yield 270 mg

(74%) (yellow). ¹H NMR (250 MHz, CD₂Cl₂): δ = 7.45 (d, ³J =

8.4 Hz, 2 H, o-C₆H₅), 7.31 (app t, app. J = 7.8 Hz, 2 H, m-C₆H₅),

7.20 (t, ³J = 7.3 Hz, 1 H, p-C₆H₅), 4.41 (q, ³J = 6.5 Hz, 1 H,

CHMe), 3.38 (br. m, 2 H, NH), 2.61 (d, ³J = 6.3 Hz, 12 H,

3

(250 MHz, CD₂Cl₂): δ = 9.04 (d, J = 4.9 Hz, 4 H, Py), 8.64 (s, 2

3

H, Py), 7.85 (t, J = 7.5 Hz, 2 H, Py), 7.69 (s, 1 H, Py), 7.38 (app.

t, app. J = 7.0 Hz, 6 H, Py, C₆H₅), 7.13–7.24 (m, 4 H, Py, C₆H₅),

4.49 (q, ³J = 6.7 Hz, 1 H, CHMe), 1.26 (d, ³J = 6.7 Hz, 3 H,

CHMe) ppm. ¹³C{¹H} NMR (62.90 MHz, CD₂Cl₂): δ = 146.0,

128.5, 126.6, 126.1 (C₆H₅), 77.4 (CHMe), 40.8 (NHMe_aMe_b), 40.7

(NHMe_aMe_b), 25.7 (CHMe) ppm. C₂₃H₂₄Cl₂N₄Ti (475.24): calcd.

C 58.13, H 5.09, N 11.79; found C 57.96, H 4.97, N 11.56.

3

NHMe₂), 1.31 (d, J = 6.7 Hz, 3 H, CHMe) ppm. ¹³C{¹H} NMR

(62.90 MHz, CD₂Cl₂): δ = 146.0, 128.5, 126.6, 126.1 (C₆H₅), 77.4

(CHMe), 40.8 (NHMe_aMe_b), 40.7 (NHMe_aMe_b), 25.7 (CHMe)

ppm. IR (KBr): ν = 3203 (s, NH), 3013 (w), 2979 (w), 2790 (w),

˜

1465 (m), 1452 (m), 1261 (w), 1112 (w), 1070 (w), 1051 (w), 1015

(m), 933 (m), 893 (s), 766 (m), 706 (m), 659 (m), 581 (m), 458 (m)

cm^–1. C₁₂H₂₃Cl₂N₃Ti (328.10): calcd. C 43.93, H 7.07, N 12.81;

found C 43.74, H 7.12, N 12.66.

[Ti{=N–[(–)-cis-myrtanyl]}Cl₂(Py)₃] (2t*): This compound was pre-

pared from unisolated 1t* [prepared from Ti(NMe₂)₄and (–)-cis-

myrtanylamine/Me₃SiCl as described above for 1a] with a pro-

cedure similar to the one described for 2d. Yield 250 mg [44%

based on starting Ti(NMe₂)₄] (orange). ¹H NMR (250 MHz,

C₆D₆): δ = 9.45 (br. s, 3 H, Py), 8.81 (br. s, 3 H, Py), 6.85 (br. t, 3

H, Py), 6.58 (br. d, 6 H, Py), 4.00 (s, 1 H, CH), 3.58 (dd, ³J =

7.5 Hz, 2 H, CH₂N), 2.52 (m, 1 H, CH), 2.28 (br. s, 2 H, CH₂),

1.95 (br. m, 1 H, CH), 1.83–1.74 (br. s, 3 H, CH, CH₂), 1.35 (m, 1

H, CH), 1.11 (s, 3 H, CH₃), 0.87 (s, 3 H, CH₃) ppm. ¹³C{¹H} NMR

(125.81 MHz, C₆D₆): δ = 152.2, 151.5, 138.3, 136.8, 124.1, 76.4,

55.1, 44.9, 42.2, 39.1, 34.1, 28.6, 27.1, 23.9, 20.1 ppm.

C₂₅H₃₂Cl₂N₄Ti (507.32): calcd. C 59.19, H 6.36, N 11.04; found C

59.04, H 6.35, N 10.91.

[Ti(=N–SiPh₃)Cl₂(Py)₃] (2d): Complex 1d (180 mg) was dissolved

in dichloromethane (2 mL) and pyridine (1 mL) was added. The

resulting solution stood overnight and was then layered with tolu-

ene (ca. 1 mL) and pentane (20 mL) to afford 2d as a crystalline

sample. The crystals were collected and washed with pentane

(3×5 mL) and dried under vacuum. Yield 220 mg (93%) (yellow).

3

¹H NMR (500 MHz, CD₂Cl₂): δ = 9.01 (d, J = 5.5 Hz, 4 H, cis-

3

Py), 8.61 (br. s, 2 H, trans-Py), 7.81 (t, J = 7.5 Hz, 2 H, cis-Py),

3

7.64 (d, J = 8.3 Hz, 6 H, C₆H₅), 7.38 (s, 1 H, trans-Py), 7.35 (d,

³J = 7.5 Hz, 3 H, C₆H₅), 7.30–7.25 (m, 12 H, cis-Py, trans-Py, C₆H₅)

ppm. ¹³C{¹H} NMR (75.81 MHz, CD₂Cl₂): δ = 151.6 (Py), 150.3

(Py), 139.2 (Py), 136.4 (C₆H₅), 135.5 (C₆H₅), 129.5 (C₆H₅), 127.8

(C₆H₅), 127.8 (Py), 124.4 (Py), 123.8 (Py) ppm. ²⁹Si NMR

[Ti(N–2-EtO–C₆H₄)Cl₂(NHMe₂)₁]₂(3): This compound was ob-

tained from a procedure similar to the one described for 1a–t. Pure

3 was obtained after recrystallization from a THF/toluene solution

layered with pentane. Yield 235 mg (70%) (dark red). ¹H NMR

(99.40 MHz, CD Cl ): δ = –43 ppm. IR (KBr): ν = 3050 (w), 1603

˜

2

(m), 1595 (m), 1485 (m), 1442 (m), 1425 (m), 1217 (m), 1109 (vs),

1068 (m), 755 (w), 693 (s), 511 (s) cm^–1. C₃₃H₃₀Cl₂N₃SiTi (629.48):

calcd. C 62.97, H 4.80, N 8.90; found C 62.90, H 4.70, N 8.81.

3

(250 MHz, CD₂Cl₂): δ = 7.58 (dd, J = 7.8 Hz, 2 H, C₆H₄), 7.05

3

(m, 4 H, C₆H₄), 6.91 (dd, J = 8.1 Hz, 2 H, C₆H₄), 5.37 (m, 2 H,

3

NH), 5.02 (qd, ³J = 7.1 Hz, 4 H, OCH₂CH₃), 2.48 (d, J = 5.8 Hz,

[Ti(=N–4-NC–C₆H₄)Cl₂(Py)₃] (2l): This compound was obtained

from 1l (100 mg) with a procedure similar to the one described for

2d. Yield 145 mg (99%) (orange). ¹H NMR (500 MHz, CD₂Cl₂): δ

= 9.07 (br. d, 4 H, cis-Py), 8.65 (br. s, trans-Py), 7.93 (br. t, 2 H,

6 H, NHMe_aMe_b), 2.35 (d, ³J = 6.1 Hz, 6 H, NHMe_aMe_b), 1.62 (t,

³J = 7.0 Hz, 6 H, OCH₂CH₃) ppm. ¹³C{¹H} NMR (125.81 MHz,

CD₂Cl₂): δ = 144.2, 142.3, 128.2, 126.7, 124.7, 111.4 (C₆H₄), 71.7

(OCH₂CH₃), 42.5 (NHMe_aMe_b), 40.0 (NHMe_aMe_b), 13.40

3

cis-Py), 7.73 (br. s, trans-Py), 7.46 (br. t, 4 H, cis-Py), 7.37 (d, J =

(OCH CH ) ppm. IR (KBr): ν = 3149 (w, NH), 2978 (m), 1473 (s),

˜

2

3

8.3 Hz, 2 H, C₆H₄), 7.32 (br. s, trans-Py), 6.84 (d, J = 8.5 Hz, 2

1254 (s, CO), 1191 (m), 1112 (m), 1041 (m), 1002 (m), 922 (m), 896

(m), 751 (m), 652 (w), 419 (w) cm^–1. C₂₀H₃₂Cl₄N₄O₂Ti₂(598.04):

calcd. C 40.17, H 5.39, N 9.37; found C 40.20, H 5.41, N 9.39.

H, C₆H₄) ppm (integration of the trans-Py signals is not given be-

cause of the poor solubility and partial decomposition of 2l in

CD₂Cl₂, which makes the integration of the trans-Py obscured by

1

[Ti[N–CH₂(CH(OCH₂)₃)]Cl₂(NHMe₂)₁]₂(4): This compound was

obtained from a procedure similar to the one described for 1a–t.

Yield 260 mg (89%) (orange). The very poor solubility of 4 in

free pyridine signals). H NMR (250 MHz, [D₅]Pyridine): δ = 7.40

(d, 2 H, C₆H₄), 7.14 (d, 2 H, C₆H₄) ppm. The low solubility and

partial decomposition of 2l in CD₂Cl₂precluded its ¹³C NMR

1

CD₂Cl₂and in [D₈]THF precluded its H and ¹³C NMR analysis.

analysis. IR (KBr): ν = 2221 (s, CN), 1603 (s), 1587 (s), 1484 (s),

˜

1

In [D₅]Py the HNMe₂ligands are displaced by [D₅]Py ligands. H

1442 (s), 1347 (s), 1212 (m), 1160 (m), 1043 (m), 966 (m), 841 (s),

759 (m), 700 (s), 680 (m), 638 (m), 549 (m). C₂₂H₁₉Cl₂N₅Ti

(472.19): calcd. C 55.96, H 4.06, N 14.83; found C 55.64, H 3.96,

N 14.63.

NMR (250 MHz, [D₅]Py): δ = 4.13 (br., 2 H), 3.90–3.25 (br., app

t), 1.96 (br., 4 H), 1.75–1.56 (br., 4 H) ppm. IR (KBr): ν = 3215

˜

(w, NH), 2983 (m), 2917 (s), 2773 (s), 1459 (m), 1257 (w, CO), 1126

(s), 1043 (s), 1029 (s), 981 (m), 893 (m), 821 (m), 699 (m), 463 (m)

cm^–1. C₁₄H₃₂Cl₄N₄O₂Ti₂(525.98): calcd. C 31.97, H 6.13, N 10.65;

found C 32.07, H 6.09, N 10.66.

[Ti[=N(C₆H₁₀CϵCH)]Cl₂(Py)₃] (2r): This compound was obtained

from 1r (100 mg) with a procedure similar to the one described for

1

2d. Yield 100 mg (69%) (ochre). H NMR (500 MHz, CD₂Cl₂): δ

= 9.20 (d, ³J = 5.0 Hz, 4 H, cis-Py), 8.65 (br. s, 2 H, trans-Py), 7.85

[Ti[N–CH₂(CHO(CH₂)₃)]Cl₂(Py)₁]₂(5): This compound was only

obtained as a few red crystals by the crystallization of 4 in pyridine/

toluene solutions. Attempted large scale synthesis (even in hot pyri-

dine) gave only insoluble materials (precluding NMR analysis), and

with an elemental analysis close to that of 4 which proves that

3

(t, J = 7.6 Hz, 2 H, cis-Py), 7.66 (br. s, 1 H, trans-Py), 7.40 (t, J

= 6.6 Hz, 4 H, cis-Py), 7.18 (br. s, 2 H, trans-Py), 2.36 (s, 1 H,

ϵCH), 1.64–1.48 (m, 6 H, CH₂), 1.33–1.22 (br. m, 3 H, CH₂,

CH_aH_b), 1.13 (m, 1 H, CH_aH_b) ppm. ¹³C{¹H} NMR (125.81 MHz,

Eur. J. Inorg. Chem. 2006, 4503–4518

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4515

C. Lorber, R. Choukroun, L. Vendier

FULL PAPER

New York, 1998; c) P. D. Bolton, P. Mountford, Adv. Synth.

Catal. 2005, 347, 355–366; d) P. Mountford, Chem. Commun.

1997, 2127–2134; e) L. H. Gade, P. Mountford, Coord. Chem.

Rev. 2001, 216–217, 65–97; f) A. P. Duncan, R. G. Bergman,

Chem. Rec. 2002, 2, 431–445.

D. N. Williams, J. P. Mitchell, A. D. Poole, U. Siemeling, W.

Clegg, D. C. R. Hockless, P. A. O’Neil, V. C. Gibson, J. Chem.

Soc., Dalton Trans. 1992, 739–751.

the substitution of NHMe₂in 4 by Py is difficult (vide infra). In

consequence, 5 was only characterized by X-ray analysis.

[Ti{=N–[(S)-(–)-CHMePh]}Cl₂(NHMe₂)₁]₂(6*): This compound

was observed in the synthesis of 1s* when only 0.8 equiv. of the

chiral amine was treated with Ti(NMe₂)₄(1 equiv.) and Me₃SiCl

(10 equiv.). ¹H NMR (250 MHz, CD₂Cl₂): δ = 7.70 (d, ³J = 8.3 Hz,

4 H, C₆H₅), 7.40 (m, 6 H, C₆H₅), 5.62 (q, ³J = 6.8 Hz, 2 H, CHMe),

3.00 (br. m, 4 H, NH), 2.59 (d, ³J = 6.1 Hz, 6 H, NHMe₂), 2.45

[2]

[3]

[4]

R. R. Schrock, Acc. Chem. Res. 1990, 23, 158–165.

3

(d, J = 5.9 Hz, 6 H, NHMe₂), 1.80 (d, J = 6.8 Hz, 6 H, CHMe)

a) M. C. W. Chan, K. C. Chen, C. I. Dalby, V. C. Gibson, A.

Kohlmann, I. R. Little, W. Reed, Chem. Commun. 1998, 1673–

1674; b) S. Scheuer, J. Fischer, J. Kress, Organometallics 1995,

14, 2627–2629; c) D. A. Pennington, M. Bochmann, S. J. Lanc-

aster, P. N. Horton, M. B. Hursthouse, Polyhedron 2005, 24,

151–156.

ppm.

[(Me₂HN)₂Cl₂Ti(=N–Me₂C₆H₂–C₆H₂Me₂–N=)TiCl₂(NHMe₂)₂]

(7): This compound was obtained from a procedure similar to the

one described for 1a–t. Yield 280 mg (77%) (yellow). ¹H NMR

3

(250 MHz, CD₂Cl₂): δ = 6.98 (s, 4 H, C₆H₂), 3.59 (m, J = 6.1 Hz,

[5]

[6]

C. Lorber, B. Donnadieu, R. Choukroun, J. Chem. Soc., Dal-

ton Trans. 2000, 4497–4498.

4 H, NH), 2.75 (d, ³J = 6.2 Hz, 24 H, NHMe₂), 2.56 (s, 12 H,

C₆H₂Me₂) ppm. ¹³C{¹H} NMR (125.81 MHz, CD₂Cl₂): δ = 159.4,

134.2, 133.9, 124.9 (C₆H₂), 41.0 (NHMe₂), 19.0 (C₆H₂Me₂) ppm.

a) A. J. Nielson, M. W. Glenny, C. E. F. Rickard, J. Chem. Soc.,

Dalton Trans. 2001, 232–239; b) N. A. H. Male, M. E. G. Skin-

ner, S. Y. Bylikin, P. J. Wilson, P. Mountford, M. Schröder, In-

org. Chem. 2000, 39, 5483–5491; c) N. Adams, P. D. Bolton,

S. R. Dubberley, A. J. Sealey, A. R. Cowley, P. Mountford, P. J.

Wilson, M. Schröder, D. Cowell, C. M. Grant, N. Friederichs,

B. Wang, M. Kranenburg, H. J. Arts, Chem. Commun. 2004,

10, 434–435.

IR (KBr): ν = 3251 (s, NH), 2972 (m), 2936 (m), 1465 (m), 1459

˜

(m), 1311 (s), 1117 (w), 1093 (w), 1020 (m), 1006 (m), 894 (m), 859

(m), 803 (w), 758 (w), 735 (w), 462 (w), 415 (w) cm^–1.

C₂₄H₄₄Cl₄N₆Ti₂(654.19): calcd. C 44.06, H 6.78, N 12.85; found

C 43.93, H 6.84 N 12.62.

[(Py)₃Cl₂Ti(=N–Me₂C₆H₂–C₆H₂Me₂–N=)TiCl₂(Py)₃] (8): This

compound was obtained from 7 (100 mg) with a procedure similar

to the one described for 2d. Yield 137 mg (94%) (orange). ¹H NMR

(250 MHz, [D₅]Py): δ = 7.31 (s, 4 H, C₆H₂), 2.79 (s, 12 H, Me)

ppm. The very poor solubility in CD₂Cl₂precluded its ¹³C NMR

[7]

[8]

a) K. E. Meyer, P. J. Walsh, R. G. Bergman, J. Am. Chem. Soc.

1995, 117, 974–982; b) K. E. Meyer, P. J. Walsh, R. G.

Bergman, J. Am. Chem. Soc. 1994, 116, 2669–2670; c) G. K.

Cantrell, T. Y. Meyer, Chem. Commun. 1997, 2, 1551–1552; d)

G. K. Cantrell, T. Y. Meyer, Organometallics 1997, 16, 5381–

5883; e) J. M. McInnes, P. Mountford, Chem. Commun. 1998,

1669–1670.

S. A. Blum, R. G. Bergman, Organometallics 2004, 23, 4003–

4005.

W. A. Nugent, Inorg. Chem. 1983, 22, 955–969.

analysis. IR (KBr): ν = 1604 (s), 1444 (vs), 1299 (s), 1217, 1069,

˜

1012 (m), 681 (w), 754 (m), 695 (vs), 637, 429 (m) cm^–1.

C₄₆H₄₆Cl₄N₈Ti₂(948.46): calcd. C 58.25, H 4.89, N 11.81; found

C 57.99, H 4.71, N 11.55.

[9]

[Ti(N–2,6-iPr₂–C₆H₃)I₂(thf)₂]₂(9): A THF solution (5 mL) of

Ti(NMe₂)₄(250 mg, 1.115 mmol) was treated with 2,6-iPr₂–

C₆H₃NH₂(1 equiv., 1.115 mmol) at room temperature. To this

solution, MeI (1.58 g) was slowly and carefully added. The re-

sulting solution was stirred at room temp. for 1 d. Toluene (5 mL)

were added and the white precipitate of Me₄NI was filtered and

washed with toluene(2×3 mL). The volatiles were removed under

vacuum, and the resulting sticky solid was washed with pentane

(2×10 mL) and dried under vacuum to afford the product. Yield

[10]

a) S. Y. Lee, R. G. Bergman, J. Am. Chem. Soc. 1995, 117,

5877–5878; b) J. L. Bennett, P. T. Wolczanski, J. Am. Chem.

Soc. 1997, 119, 10696–10709; c) A. J. Blake, P. E. Collier, P.

Mountford, L. H. Gade, M. Schubart, M. McPartlin, I. J.

Scowen, Chem. Commun. 1997, 2, 1555–1556; d) P. J. Walsh,

F. J. Hollander, R. G. Bergman, J. Am. Chem. Soc. 1993, 12,

3705–3723; e) H. M. Hoyt, F. E. Michael, R. G. Bergman, J.

Am. Chem. Soc. 2004, 126, 1018–1019.

a) D. J. M. Trösch, P. E. Collier, A. Bashall, L. H. Gade, M.

McPartlin, P. Mountford, S. Radojevic, Organometallics 2001,

20, 3308–3313; b) P. J. Walsh, A. M. Baranger, R. G. Bergman,

J. Am. Chem. Soc. 1992, 114, 1708–1719; c) S. Y. Lee, R. G.

Bergman, Tetrahedron 1995, 51, 4255–4276; d) J. L. Polse,

R. A. Andersen, R. G. Bergman, J. Am. Chem. Soc. 1998, 120,

13405–13414; e) B. D. Ward, A. Maisse-François, L. H. Gade,

P. Mountford, Chem. Commun. 2004, 10, 704–705; f) K. S. Lo-

kare, J. T. Ciszewski, A. L. Odom, Organometallics 2004, 23,

5386–5388; g) F. E. Michael, A. P. Duncan, Z. K. Sweeney,

R. G. Bergman, J. Am. Chem. Soc. 2005, 127, 1752–1764.

a) S. M. Pugh, P. Mountford, D. J. M. Trösch, L. H. Gade, D. J.

Wilson, F. G. N. Cloke, P. B. Hitchcock, J. F. Nixon, A. Bash-

all, M. McPartlin, Organometallics 2000, 19, 3205–3210; b) I.

Meisel, G. Hertl, K. Weiss, J. Mol. Catal. 1986, 36, 159–162;

c) S.-H. Hsu, J.-C. Chang, C.-L. Lai, C.-H. Hu, H. M. Lee, G.-

H. Lee, S.-M. Peng, J.-H. Huang, Inorg. Chem. 2004, 43, 6786–

6792; d) T. E. Hanna, I. Keresztes, E. Lobkovsky, W. H. Bern-

skoetter, P. J. Chirik, Organometallics 2004, 23, 3448–3458.

For some examples of hydroamination with imido–titanium

catalysts, see a) C. Lorber, R. Choukroun, L. Vendier, Organo-

metallics 2004, 23, 1845–1850; b) L. Ackermann, R. G.

Bergman, R. N. Loy, J. Am. Chem. Soc. 2003, 125, 11956–

11963; c) T.-G. Ong, G. P. A. Yap, D. S. Richeson, Organome-

tallics 2002, 21, 2839–2841; d) H. Wang, H.-S. Chan, Z. Xie,

Organometallics 2005, 24, 3772–3779.

[11]

1

550 mg (79%) (orange). H NMR (250 MHz, C₆D₆): δ = 6.96 (d,

³J = 7.7 Hz, 2 H, C₆H₃), 6.82 (t, ³J = 7.6 Hz, 1 H, C₆H₃), 4.89

3

(sept, J = 6.8 Hz, 2 H, CHMe₂), 4.32 (br. t, 8 H, OCH₂), 1.45 (d,

³J = 6.8 Hz, 12 H, CHMe₂), 1.24 (br. t, 8 H, CH₂) ppm. ¹³C{¹H}

NMR (62.90 MHz, C₆D₆): δ = 160.0, 144.3, 125.0, 122.8 (C₆H₃),

77.1 (OCH₂), 28.6 (CHMe₂), 25.2 (CH₂), 24.8 (CHMe₂) ppm. IR

(KBr): ν = 2954 (vs), 1459 (s), 1326 (s), 1279 (s), 1175 (w), 1037

˜

(w), 1011 (s), 921 (m), 853 (vs), 751 (s), 686 (w), 544 (w) cm^–1.

C₂₀H₃₃I₂NO₂Ti (621.16): calcd. C 38.67, H 5.35, N 2.25; found C

35.99, H 4.96, N 2.05 (the elemental analysis always gave low C

and N content).

[12]

[13]

Supporting Information (see footnote on the first page of this arti-

1

cle): H NMR spectra of complexes 1p and 9.

Acknowledgments

We are grateful to the CNRS for financial support.

[1] a) D. E. Wigley, Progress in Inorganic Chemistry. (Ed.: K. D.

Karlin), Interscience: 1994, vol. 42, 239–482; b) W. A. Nugent,

J. M. Mayer, Metal-Ligand Multiple Bonds. Wiley-Interscience,

4516

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Eur. J. Inorg. Chem. 2006, 4503–4518

A General and Facile One-Step Synthesis of Imido–Titanium(IV) Complexes

FULL PAPER

[14]

4037; c) R. Baumann, W. M. Davis, R. R. Schrock, J. Am.

Chem. Soc. 1997, 119, 3830–3831.

For selected examples of hydroamination with Group 4 pre-

catalysts, see a) Y. H. Li, Y. H. Shi, A. L. Odom, J. Am. Chem.

Soc. 2004, 126, 1794–1803; b) L. Ackermann, Organometallics [29]

2003, 22, 4367–4368; c) B. Ramanathan, J. A. Keith, D. Arm-

strong, A. L. Odom, Org. Lett. 2004, 6, 2957–2960; d) F.

Pohlki, I. Bytschov, H. Siebeneicher, A. Heutling, W. A. König,

S. Doye, Eur. J. Org. Chem. 2004, 1967–1972; e) J. A. Bexrud,

J. D. Beard, D. C. Leitch, L. L. Schafer, Org. Lett. 2005, 7,

1959–1962; f) A. Tillack, V. Khedkar, H. J. Jiao, M. Beller, Eur.

J. Org. Chem. 2005, 5001–5012; g) D. V. Gribkov, K. C.

Hultzsch, Angew. Chem. Int. Ed. 2004, 44, 5542–5546.

a) R. T. Ruck, R. G. Bergman, R. L. Zuckerman, S. W. Krska,

Angew. Chem. Int. Ed. 2004, 43, 5372–5374; b) R. T. Ruck,

R. G. Bergman, Angew. Chem. Int. Ed. 2004, 43, 5375–5377; c)

F. Basuli, H. Aneetha, J. C. Huffman, D. J. Mindiola, J. Am.

Chem. Soc. 2005, 127, 17992–17993.

a) C. C. Cummins, C. P. Schaller, G. D. Van Duyne, P. T. Wol-

czanski, A. W. C. Chan, R. Hoffmann, J. Am. Chem. Soc. 1991,

113, 2985–2994; b) J. L. Bennett, P. T. Wolczanski, J. Am.

Chem. Soc. 1994, 116, 2179–2180; c) H. Bürger, U. Wannagat,

Monatsh. Chem. 1963, 94, 761–764; d) N. W. Alcock, M.

Pierce-Butler, G. R. Willey, J. Chem. Soc., Dalton Trans. 1976,

707–713; e) R. Wollert, S. Wocadlo, K. Dehnicke, H. Goes-

mann, D. Fenske, Z. Naturforsch., Teil B 1992, 47, 1386; f) R.

Schlichenmaier, J. Strähle, Z. Anorg. Allg. Chem. 1993, 619,

1526–1529; g) L. M. Slaughter, P. T. Wolczanski, T. R. Klinck-

man, T. R. Cundari, J. Am. Chem. Soc. 2000, 122, 7953–7975;

h) M. A. Putzer, B. Neumüller, K. Dehnicke, Z. Anorg. Allg.

Chem. 1998, 624, 57–64; i) J. D. Gardner, D. A. Robson, L. H.

Rees, P. Mountford, Inorg. Chem. 2001, 40, 820–824; j) J. R.

Hagadorn, J. Arnold, Organometallics 1998, 17, 1355–1368.

J. E. Hill, P. E. Fanwick, I. P. Rothwell, Inorg. Chem. 1991, 30,

1143–1144.

τ is the angular parameter commonly used to describe the ge-

ometry around the metal center in pentacoordinate complexes

and defined as τ = (α–β)/60 (α and β are the two largest L–M–

L bond angles, with α Ն β). A. W. Addison, T. N. Rao, J. Reed-

ijk, J. V. van Rijn, J. Chem. Soc., Dalton Trans. 1984, 1349–

1356.

a) D. L. Thorn, W. A. Nugent, J. Am. Chem. Soc. 1981, 103,

357–363; b) W. A. Nugent, B. L. Haymore, Coord. Chem. Rev.

1980, 31, 123–175; c) S. Gambarotta, C. Floriani, A. Chiesi-

Villa, C. Guastini, J. Chem. Soc., Chem. Commun. 1982, 1015–

1017.

[15]

[16]

[17]

S. A. Blum, V. A. Rivera, R. T. Ruck, F. E. Michael, R. G.

Bergman, Organometallics 2005, 24, 1647–1659.

[30]

[31]

a) C. J. Carmalt, A. Newport, I. P. Parkin, P. Mountford, A. J.

Sealey, S. R. Dubberley, J. Mater. Chem. 2003, 13, 84–87; b)

C. J. Carmalt, A. C. Newport, I. P. Parkin, A. J. P. White, D. J.

Williams, J. Chem. Soc., Dalton Trans. 2002, 4055–4059; c)

C. H. Winter, P. H. Sheridan, T. S. Lewkebandara, M. J. Heeg,

J. W. Proscia, J. Am. Chem. Soc. 1992, 114, 1095–1097; d) O. J.

Bchir, K. M. Green, M. S. Hlad, T. J. Anderson, B. C. Brooks,

C. B. Wilder, D. H. Powell, L. McElwee-White, J. Organomet.

Chem. 2003, 684, 338–350; e) O. J. Bchir, K. M. Green, H. M.

Ajmera, E. A. Zapp, T. J. Anderson, B. C. Brooks, L. L. Reit-

fort, D. H. Powell, K. A. Abboud, L. McElwee-White, J. Am.

Chem. Soc. 2005, 127, 7825–7833.

a) Z. Peng, Angew. Chem. Int. Ed. 2004, 43, 930–935; b) A. R.

Moore, H. Kwen, A. M. Beatty, E. A. Maatta, Chem. Commun.

2000, 1793–1794; c) J. B. Strong, G. P. A. Yap, R. Ostrander,

L. M. Liable-Sands, A. L. Rheingold, R. Thouvenot, P. Gouz-

erh, E. A. Maatta, J. Am. Chem. Soc. 2000, 122, 639–649.

T. E. Hanna, Coord. Chem. Rev. 2004, 248, 429–440.

a) F. Wolff, C. Lorber, R. Choukroun, B. Donnadieu, Eur. J.

Inorg. Chem. 2004, 2861–2867; b) F. Wolff, R. Choukroun, C.

Lorber, B. Donnadieu, Eur. J. Inorg. Chem. 2003, 628–632; c)

F. Wolff, C. Lorber, R. Choukroun, B. Donnadieu, Inorg.

Chem. 2003, 42, 7839–7845; d) C. Lorber, B. Donnadieu, R.

Choukroun, Organometallics 2000, 19, 1963–1966; e) R. Chou-

kroun, C. Lorber, B. Donnadieu, Organometallics 2004, 23,

1434–1437; f) R. Choukroun, C. Lorber, L. Vendier, B. Donna-

dieu, Organometallics 2004, 23, 5488–5492; g) R. Choukroun,

C. Lorber, B. Donnadieu, Organometallics 2002, 21, 1124–

1126; h) R. Choukroun, B. Donnadieu, C. Lorber, P. M. Pellny,

W. Baumann, U. Rosenthal, Chem. Eur. J. 2000, 6, 4505–4509;

i) C. Lorber, F. Wolff, R. Choukroun, L. Vendier, Eur. J. Inorg.

Chem. 2005, 2850–2859.

[32]

[33]

[18]

For a review on the stereochemistry of polymerization, and an

example of polymerization with the use of an enantiomerically

pure catalyst, see a) G. W. Coates, Chem. Rev. 2000, 100, 1223–

1252; b) A. E. Cherian, E. B. Lobkovsky, G. W. Coates, Chem.

Commun. 2003, 2566–2567.

[19]

[20]

[34]

[35]

[36]

For some examples of the use of enantiomerically pure amines

as substrates for Ti-catalyzed hydroamination of alkynes, see

ref.^[13a]and ref.^[14c]

.

For an example of a chiral molybdenum diimido complex, see

E. A. Kretzschmar, J. Kipke, J. Sundermeyer, Chem. Commun.

1999, 2381–2388.

Complex 1s* has also been obtained as yellow needles that

crystallized in the orthorhombic space group P2₁2₁2₁[a:

6.5483(2), b: 7.7647(3), c: 33.3440(9)]. Bond lengths and angles

are similar, but the overall structure differs by the position of

the N–H bonds: syn in the P 2₁structure versus anti in the P

2₁2₁2₁structure, and by the NH···Cl network.

Overall, complex 6s* only differs from 1s* by the loss of one

NHMe₂ligand/Ti center. To explain its formation, we suspect

the concomitant formation [when Ti(NMe₂)₄/R*NH₂ratio Ͼ

1] of a small amount of [TiCl₃(NMe₂)(HNMe₂)]₂that would

trap some of the HNMe₂ligand needed to form 1s* and thus

6s* is formed. These studies, that are related to the mechanism

of the general reaction Ti(NMe₂)₄/RNH₂/Me₃SiCl, are under

current investigations and will be reported in due course.

The chiral imido–vanadium analogue complex has been pre-

pared similarly and its structure has been established by X-ray

structure determination. C. Lorber, Unpublished result.

Selected examples of Group 5/6 diimido complexes: a) E. A.

Maatta, D. D. Devore, Angew. Chem. Int. Ed. Engl. 1988, 27,

569–571; b) D. E. Wheeler, J.-F. Wu, E. A. Maatta, Polyhedron

1998, 17, 969–976; c) A. Antinolo, I. Dorado, M. Fajardo, A.

Garces, I. Lopez-Solera, C. Lopez-Mardomingo, M. M. Kub-

icki, A. Otero, S. Prashar, Eur. J. Inorg. Chem. 2004, 1299–

1310; d) S. Prashar, M. Fajardo, A. Garces, I. Dorado, A. Anti-

nolo, A. Otero, I. Lopez-Solera, C. Lopez-Mardomingo, J. Or-

ganomet. Chem. 2004, 689, 1304–1314.

[37]

[21]

[22]

[23]

[24]

C. Lorber, R. Choukroun, B. Donnadieu, Inorg. Chem. 2002,

41, 4217–4226.

C. Lorber, R. Choukroun, B. Donnadieu, Inorg. Chem. 2003,

42, 673–675.

A. J. Blake, P. E. Collier, S. C. Dunn, W.-S. Li, P. Mountford,

O. V. Shishkin, J. Chem. Soc., Dalton Trans. 1997, 1549–1558.

a) A. J. Nielson, Inorg. Chim. Acta 1988, 154, 177–182; b) T. S.

Lewkebandara, P. H. Sheridan, M. J. Heeg, A. L. Rheingold,

C. H. Winter, Inorg. Chem. 1994, 33, 5879–5889.

[38]

[39]

[25]

[26]

Y. Li, S. Banerjee, A. L. Odom, Organometallics 2005, 24,

3272–3278.

N. Adams, H. R. Bigmore, T. L. Blundell, C. L. Boyd, S. R.

Dubberley, A. J. Sealey, A. R. Cowley, M. E. G. Skinner, P.

Mountford, Inorg. Chem. 2005, 44, 2882–2894.

[27]

[28]

E. Benzing, W. Kornicker, Chem. Ber. 1961, 94, 2263–2267.

For some typical examples of the use of Me₃SiCl as a chlorinat-

ing agent for the cleavage of Ti–N_amidobond in Group 4 com-

plexes, see a) D. J. Arney, M. A. Bruck, S. R. Huber, D. E. Wig-

ley, Inorg. Chem. 1992, 31, 3749–3755; b) G. M. Diamond,

R. F. Jordan, J. L. Petersen, Organometallics 1996, 15, 4030–

[40]

For an example of cleavage of Ti–NMe₂with CH₃I, see A. R.

Johnson, P. W. Wanandi, C. C. Cummins, D. M. Davis, Orga-

nometallics 1994, 13, 2907–2909.

Eur. J. Inorg. Chem. 2006, 4503–4518

www.eurjic.org

4517

C. Lorber, R. Choukroun, L. Vendier

FULL PAPER

[41] D. C. Bradley, I. M. Thomas, J. Chem. Soc. 1960, 3857–3861.

[42] A. Altomare, G. Cascarano, G. Giacovazzo, A. Guagliardi,

M. C. Burla, G. Polidori, M. Camalli, J. Appl. Crystallogr.

1994, 27, 435.

[44] L. J. Farrugia, J. Appl. Crystallogr. 1999, 32, 837–838.

[45] N. Walker, D. Stuart, Acta Crystallogr., Sect. A 1983, 39, 158–

166.

[46] A. L. Spek, Acta Crystallogr., Sect. A 1990, 46, C34.

[43] G. M.

Sheldrick,

SHELX97

[Includes

SHELXS97, [47] G. Bernardinelli, H. D. Flack, Acta Crystallogr., Sect. A 1985,

SHELXL97, CIFTAB] - Programs for Crystal Structure Analy-

sis (Release 97–2). Institut für Anorganische Chemie der Uni-

versität, Tammanstrasse 4, D-3400 Göttingen, Germany, 1998.

41, 500–511.

Received: May 22, 2006

Published Online: August 7, 2006

4518

www.eurjic.org

Eur. J. Inorg. Chem. 2006, 4503–4518

Article Doi

A general and facile one-step synthesis of imido-titanium(IV) complexes: Application to the synthesis of compounds containing functionalized or chiral imido ligands and bimetallic diimido architectures

DOI: 10.1002/ejic.200600475

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