C-H activation of a MeN grouping in one of the CH2NMe2 ortho substituents of a NCN 'pincer' ligand in tungsten chemistry: X-ray structure of [WCl2(NPh)(C6H3{CH2NMeCH 2}-2-{CH2NMe2}-6)]

Article abstract of DOI:10.1016/S0022-328X(99)00199-0

Reaction of the aryl and alkyl metal derivatives, [Li(C₆H₃(CH₂NMe₂) ₂-2,6)]₂ (1), in situ prepared 'Zn(C₆H₃(CH₂NMe₂) ₂-2,6)_2' (2), [Li(CH₂{C₆H(CH₂NMe₂) ₂-2,6-Me₂-3,5})] (3) and [Zn(CH₂{C₆H(CH₂NMe₂) ₂-2,6-Me₂-3,5})₂] (4), respectively, with either WOCl₄ or [W(NPh)Cl₄(Et₂O)] in Et₂O yielded insoluble products. According to elemental analysis and mass balance the adducts that were formed contained all of the starting compounds, including the respective Li and Zn salts eventually formed. However, when the arylzinc reagent 2 was reacted with [W(NPh)Cl₄(Et₂O)] in CH₂Cl₂, [WCl₂(NPh)(C₆H₃{CH₂N(Me)CH ₂}-2-{CH₂NMe₂}-6)] (6) was formed, which was isolated in high yield. The single-crystal X-ray determination of 6 showed a NCN ligand that is η³-mer-N,C,N-bonded to the tungsten(VI) center via the (aryl)C_ipso carbon and the two ortho-N-donor atoms. As one of the NCH₃ groups has undergone C-H activation, thus forming an azatungstacyclopropane ring, the NCN-pincer ligand is overall bonded to the tungsten centre as a tetradentate, η⁴-N,C,N,C coordinating dianionic ligand. The corresponding tungsten(VI) alkylidene complex [W(CH₂SiMe₃)(NPh)(C₆H ₃{=CHN(Me)CH₂}-2-(CH₂NMe₂)-6)] (7) was generated by reaction of 6 with two equivalents of LiCH₂SiMe₃.

Full text of DOI:10.1016/S0022-328X(99)00199-0

www.elsevier.nl/locate/jorganchem
Journal of Organometallic Chemistry 585 (1999) 93–99
C–H activation of a MeN grouping in one of the CH2NMe2 ortho
substituents of a NCN ‘pincer’ ligand in tungsten chemistry: X-ray
structure of [WCl2(NPh)(C6H3{CH2NMeCH2}-2-{CH2NMe2}-6)]
Jim A.M. Brandts a, Elbertus Kruiswijk a, Jaap Boersma a, Anthony L. Spek b,1,
Gerard van Koten a,*
a Debye Institute, Department of Metal-Mediated Synthesis, Utrecht Uni6ersity, Padualaan 8, NL-3584 CH Utrecht, The Netherlands
b Bij6oet Institute for Biomolecular Research, Department of Crystal and structural Chemistry, Utrecht Uni6ersity, Padualaan 8,
NL-3584 CH Utrecht, The Netherlands
Received 1 January 1999
Abstract
Reaction of the aryl and alkyl metal derivatives, [Li(C6H3(CH2NMe2)2-2,6)]2 (1), in situ prepared ‘Zn(C6H3(CH2NMe2)2-2,6)2’
(2), [Li(CH2{C6H(CH2NMe2)2-2,6-Me2-3,5})] (3) and [Zn(CH2{C6H(CH2NMe2)2-2,6-Me2-3,5})2] (4), respectively, with either
WOCl4 or [W(NPh)Cl4(Et2O)] in Et2O yielded insoluble products. According to elemental analysis and mass balance the adducts
that were formed contained all of the starting compounds, including the respective Li and Zn salts eventually formed. However,
when the arylzinc reagent 2 was reacted with [W(NPh)Cl4(Et2O)] in CH2Cl2, [WCl2(NPh)(C6H3{CH2N(Me)CH2}-2-{CH2NMe2}-
6)] (6) was formed, which was isolated in high yield. The single-crystal X-ray determination of 6 showed a NCN ligand that is
h3-mer-N,C,N-bonded to the tungsten(VI) center via the (aryl)Cipso carbon and the two ortho-N-donor atoms. As one of the
NCH3 groups has undergone C–H activation, thus forming an azatungstacyclopropane ring, the NCN-pincer ligand is overall
bonded to the tungsten centre as a tetradentate, h4-N,C,N,C coordinating dianionic ligand. The corresponding tungsten(VI)
alkylidene complex [W(CH2SiMe3)(NPh)(C6H3{ꢀCHN(Me)CH2}-2-(CH2NMe2)-6)] (7) was generated by reaction of 6 with two
equivalents of LiCH2SiMe3. © 1999 Elsevier Science S.A. All rights reserved.
Keywords: Tungsten; C–H activation; Azatungstacyclopropane ring; C,N-chelate; Zinc
rearrangements [3] and interesting intramolecular
aminomethyl C–H activation reactions [4]. Despite the
stability of these complexes often high catalytic activity
in ring-opening metathesis polymerization (ROMP) re-
actions with strained cyclic olefins like norbornene and
dicyclopentadiene was found [2c].
To extend the number of tungsten complexes with
the C,N-chelating manifold we investigated the synthe-
sis of W(VI) complexes with aryl-, [C6H3(CH2NMe2)2-
2,6]− (I), and alkyl-, [CH2{C6H(CH2NMe2)2-2,6-
Me2-3,5})]− (II), pincer ligands which, so far, have not
been used in the field of W(VI) chemistry (see Fig. 1).
To generate the W(VI) alkylidene species containing
these new ligands, [Li(C6H3(CH2NMe2)2-2,6)]2 (1) [5],
in situ prepared ‘Zn(C6H3(CH2NMe2)2-2,6)2’ (2),
1. Introduction
Recently, we reported a number of Ta(V) [1] and
W(VI) [2] alkylidenes that contain either an ortho-
chelating bidentate mono aminoaryl or a bis ortho-
chelating terdentate diaminoaryl ligand. The presence
of a monoanionic, chelating ortho-amine ligand not
only stabilizes the resulting aryl–Ta(V) and –W(VI)
complexes but is also responsible for intramolecular
* Corresponding author. Tel.: +31-30-2533120; fax: +31-30-
2523615.
E-mail address: g.vankoten@chem.uu.nl (G. van Koten)
1 Correspondence pertaining to crystallographic studies to this
author. E-mail: a.l.spek@chem.uu.nl.
0022-328X/99/$ - see front matter © 1999 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(99)00199-0

94
J.A.M. Brandts et al. / Journal of Organometallic Chemistry 585 (1999) 93–99
[Li(CH2{C6H(CH2NMe2)2-2,6-Me2-3,5})] (3) [6], [Zn-
(CH2{C6H(CH2NMe2)2-2,6-Me2-3,5})2] (4) and [Me3Si-
CH2{C6H(CH2NMe2)2-2,6-Me2-3,5}] (5) [6], respec-
tively, were reacted with [W(NPh)(CH2SiMe3)3Cl] [7].
These reactions always resulted in the formation of
mixtures of compounds, e.g. several W(VI) alkylidenes
and the parent protonated ligands, which could not be
separated by crystallization or washing procedures.
Therefore, we decided to synthesize complexes such as
[WOCl3L] and [W(NPh)Cl3L] (L=ligand I or II) first,
and to generate the alkylidene moiety at a later stage.
Here we report results obtained from reactions between
1–4 and WOCl4 and [W(NPh)Cl4(Et2O)], respectively.
The main products of these reactions were insoluble
precipitates. However, products originating from unex-
pected C–H activation were also found when
[W(NPh)Cl4(Et2O)] was reacted with 2 in CH2Cl2 yield-
ing [WCl2(NPh)(C6H3{CH2N(Me)CH2}-2-{CH2Me2}-
6)] (6) and the corresponding alkylidene com-
2. Results and discussion
The reactions between compounds 1–4 and WOCl4
or [W(NPh)Cl4(Et2O)] in Et2O give insoluble, intense
colored solids (Table 1).
The mass balance and the elemental analysis of the
complexes formed suggested that the products obtained
from the reactions between 1–4 and WOCl4 contained
all of the starting compounds, as well as the lithium/
zinc chloride eventually formed. Subsequent slurry re-
actions of the insoluble reaction products with
Li–O–tBu to convert the blue/grey solids into more
soluble tert-butoxy complexes failed. Furthermore, at-
tempts to decomplex the probably strongly intermolec-
ularly coordinated complexes by addition of
coordinating bases like TMEDA and pyridine likewise
did not result in the formation of soluble products.
The reactions of 1–4 with [W(NPh)Cl4(Et2O)] yielded
brown/beige solutions at −78°C from which solids
precipitated upon warming to room temperature (r.t.).
The mass balance of the precipitates suggested that
again complexes were formed which contain all the
starting compounds, although in this case no satisfac-
tory elemental analysis could be obtained. Also for
these products additional slurry reactions with Li–O–
tBu or the use of strongly coordinating bases failed to
give secondary products with better solubility
properties.
plex
[W(CH2SiMe3)(NPh)(C6H3{ꢀCHN(Me)CH2}-2-
(CH2NMe2)-6)] (7) after reaction with excess
LiCH2SiMe3.
It was surprising to find that the reaction of 1 and 2
with WOCl4 and [W(NPh)Cl4(Et2O)], respectively,
yielded insoluble products, especially because the
mono-(dimethylamino)methyl analogues [WO(C6H3-
(CH2NMe2)-2)Cl3] and [W(NPh)(C6H3(CH2NMe2)-2)-
Cl3] can be made in high yields (77%) by reaction of
either WOCl4 or [W(NPh)Cl4(Et2O)] with half an equiv-
alent of [Zn(C6H3(CH2NMe2)-2)2] [3a,b]. Apparently,
the presence of an extra ortho-(dimethylamino)methyl
functionality plays a crucial role. We have shown that
the presence of this substituent can (i) cause the forma-
tion of coordination polymers [8]; (ii) accommodate an
HCl functionality by formation of an ammonium
molybdate in similar molybdenum(VI) chemistry [9];
(iii) accommodate ZnCl2 as shown in tantalum(V)
chemistry [1a] and (iv) play an important role in NCN
rearrangement reactions involving the (aryl)Cipso–M,
aryl C–H and (NCH3)C–M bonds [3]. In the present
study the presence of the second ortho-(dimethyl-
amino)methyl functionality possibly causes the forma-
tion of insoluble products by strong intermolecular
coordination to the zinc/lithium salts. This insolubility
prevented further purification and characterization of
the products. For that reason a salt-free reaction route
to the desired tungsten complexes was attempted, i.e.
the reaction of the trimethylsilyl derivative of ligand II,
[Me3SiCH2(C6H(CH2NMe2)2-2,6-Me2-3,5)] (5) with
WOCl4 and [W(NPh)Cl4(Et2O)], respectively, was un-
Fig. 1. The NCN-chelating ligands and the metalated complexes 1–5.
Table 1
Overview of the results of the reactions between the metal salts of the
ligands and tungsten complexes (stoichiometry I/II: W=1:1)
a
Compound
WOCl4
[W(NPh)Cl4(Et2O)] a
1
Purple/grey
Purple
Brown
Beige
Beige/green
Beige
0.5 Equiv. 2
3
0.5 Equiv. 4
Blue/grey b
Blue/grey c
a Et2O was used as solvent. Solutions or suspensions of 1–4 were
carefully added to solutions of the W compounds at −78°C.
b The elemental analysis of this product confirms the formation of
an addition product of the lithium salt and W compound: Anal. Calc.
for WOCl4LiC15H25N2 (%): C 30.96, H 4.33, N 4.81, Found: C 31.08,
H 4.29, N 4.63. The Li salt could not be removed by extraction with
THF.
c The elemental analysis of this product confirms the formation of
an addition product of the zinc salt and W compound: Anal. Calc.
for W2O2Cl8ZnC30H50N4(%): C 29.65, H 4.15, N 4.61, Found: C
29.81, H 4.19, N 4.48.

J.A.M. Brandts et al. / Journal of Organometallic Chemistry 585 (1999) 93–99
95
Scheme 1. Formation of the h4-N,C,N,C-pincer tungsten(VI) complex with the azatungstacyclopropane moiety. (i) In situ prepared
‘Zn(C6H3(CH2NMe2)2-2,6)2’ (2), CH2Cl2, r.t., ZnCl2(NCNH), 95% yield. (ii) 2LiCH2SiMe3, 2LiCl, -SiMe4, THF.
Fig. 2. Anisotropic displacement ellipsoid plot (ORTEP, at 50% probability level) of the molecular structure of 6, together with the adopted
numbering scheme. One disordered CH2Cl2 solvent molecule and hydrogen atoms have been omitted for clarity.
dertaken. Although this approach was applied with
success in other cases (cf. Morrison et al. [10], Knotter
et al. [11a] and Janssen et al. [11b]), we found that the
reactions yielded complicated mixtures and were very
slow, even when they were carried out under reflux
conditions for several days in different solvents.
When one equivalent of 2 was added dropwise to a
solution of [W(NPh)Cl4(Et2O)] in CH2Cl2 instead of
Et2O (stoichiometry I:W=2:1), a yellow crystalline
product could be isolated. It was identified by NMR,
elemental analysis and single-crystal X-ray diffraction
as the cyclometalated product [WCl2(NPh)(C6H3{CH2-
N(Me)CH2}-2-{CH2NMe2}-6)] (6) which was obviously
formed by C–H activation of one of the NMe2 sub-
stituents.
to the NMe groups and three AB patterns assigned to
the methylene hydrogens of the CH2N groups, i.e. these
CH2 hydrogens are diastereotopic. One set (5.32 and
5.10 ppm) shows 183W–1H coupling (2JWH=11.4 Hz).
The diastereotopicity of the NMe2 methyl groups estab-
lishes that intramolecular W–N coordination is rigid
on the NMR timescale. The 13C-{1H}-NMR data show
three signals in the benzylic region (78.1, 78.0 and 76.1
ppm) and three signals with chemical shift values char-
acteristic for NMe groups (60.3, 54.8 and 53.9 ppm).
These NMR data are characteristic and consistent with
the presence of a new NCH2 unit formed as a result of
C–H activation of one of the NMe groups of the
[C6H3(CH2NMe2)2-2,6]− ligand (see Scheme 1).
The solid state structure was determined by a single-
crystal X-ray determination and the molecular structure
with the adopted numbering scheme is depicted in Fig.
The 1H NMR spectrum of 6 shows three singlet
resonances (3.26, 3.13 and 2.84 ppm, CDCl3) assigned

96
J.A.M. Brandts et al. / Journal of Organometallic Chemistry 585 (1999) 93–99
diastereotopic CH2N protons and an AB pattern
which has been assigned to the CH2Si protons. It is
interesting to note that the alkylidene complex 7 was
formed only when two equivalents of LiCH2SiMe3
were reacted with 6. The use of other transmetallating
agents containing a-H atoms, e.g. C6H5CH2MgBr,
C6H5CMe2CH2MgCl or MeMgCl in the place of
LiCH2SiMe3, caused direct decomposition of 6 and
formation of [C6H4(CH2NMe2)2-1,3] (i.e. NCNH). No
C–H activation of a CH2SiMe3 group which would
2. Selected bond lengths and angles of 6 are given in
Table 2.
The tungsten complex contains one imidophenyl
group, two chloride atoms and an h3-mer-N,C,N-
bonded pincer ligand with an azatungstacyclopropane
unit as additional structural feature. The tungsten cen-
ter has a pseudo-octahedral coordination geometry
with mutually cis-positioned chloride atoms. The W–
Cl(1) bond is slightly shorter than the W–Cl(2) bond
with a Cl(1)–W–Cl(2) angle of almost 82°. The imido
ligand is virtually linear (W–N–C=173.6(6)°) and is
positioned trans to Cl(2). The N(101)–W(1)–C(109)
angle in the newly formed azatungstacyclopropane ring
amounts to 39.2(2)°. The size of this angle is similar to
those found in [TaCl2{C6H4(CH(Me)N(Me)CH2)–2}-
(CH2Ph)(THF)] (38.7(2)°) [4] and [TaCp*Cl2{h3-
C6H4(CH2N(Me)CH2)-2}] (40.2(3)°) [12].
lead
to
the
formation
of
[W(ꢀCHSi-
Me3)(NPh)(C6H3{CH2N(Me)CH2}-2-{CH2NMe2}-6)],
was observed. Compound 7 is very soluble in both
polar and apolar solvents but decomposes within sev-
eral hours with formation of paramagnetic tungsten
complexes and the corresponding arene NCNH, which
made complete characterization (13C-NMR, elemental
analysis) complicated. Recently, Royo et al. reported a
Ta(V) alkylidene complex which contains a similar
TaꢀCHNMe unit [12].
The tungsten alkylidene complex [W(CH2SiMe3)-
(NPh)(C6H3{ꢀCHN(Me)CH2}-2-(CH2NMe2)-6)]
(7)
can be synthesized by reaction of 6 with two equiva-
lents LiCH2SiMe3 in THF (see Scheme 1). Not only
both chlorides are replaced but also subsequent alkyli-
dene formation occurred. No information was ob-
tained whether direct elimination occurred with
LiCH2SiMe3 as a base or that first Cl substitution,
followed by a-H elimination at the NCH2-
W(CH2SiMe3) unit takes place. The 1H NMR spec-
trum of 7 in C6D6 shows the presence of an alkylidene
proton at l=9.74 ppm with a large tungsten coupling
(42.3 Hz), two AB patterns originating from the
C–H activation of NMe groups is a common phe-
nomenon in transition metal chemistry and has been
reported by different groups, e.g. Abbenhuis et al. [4],
De Castro et al. [12] and Bertuleit et al. [13]. The
mechanistic pathway involved, i.e. via s-bond
metathesis or via a stepwise process involving metal–
hydride complexes, is not clear yet, but C–H activa-
tion is facilitated when suitable anionic ligands are
present. The use of two equivalents of the anionic
NCN ligand I assures that two chloride ligands are
replaced and that one of the C–H bonds in a NMe
group is activated. The second NCN ligand is con-
verted into the protonated NCN ligand NCNH. The
resulting ZnCl2 and NCNH form an insoluble adduct
‘ZnCl2(NCNH)’ when the reaction is carried out in
CH2Cl2. However, in the absence of CH2Cl2 as a sol-
vent, the insoluble adduct which was also formed dur-
Table 2
a
Selected bond lengths (A) and angles (°) a of [WCl2(NPh)(C6H3-
,
{CH2N(Me)CH2}-2-{CH2NMe2}-6)] (6)
Bond lengths
W(1)–Cl(1)
2.4591(13)
2.5122(15)
ing the reaction of one equivalent of
2 with
W(1)–Cl(2)
[W(NPh)Cl4(Et2O)] (see Table 1), is isolated as the
main product. Most probably, the use of CH2Cl2 as a
co-solvent assures that intermediate complexes such as
[W(NPh)(NCN)Cl3] and [W(NPh)(NCN)2Cl2] remain
in solution. The spontaneous C–H bond activation at
r.t. prevented the isolation of these complexes.
W(1)–N(101)
W(1)–N(102)
W(1)–N(201)
W(1)–C(101)
W(1)–C(109)
N(101)–C(109)
N(201)–C(201)
N(102)–C(111)
N(102)–C(112)
N(101)–C(108)
2.142(5)
2.360(6)
1.745(4)
2.109(5)
2.160(7)
1.443(8)
1.390(7)
1.483(8)
1.487(8)
1.473(8)
3. Experimental
All reactions were carried out under an atmos-
phere of dry N2, using standard Schlenk techniques.
All solvents were distilled from sodium under nitro-
gen, prior to use, except CH2Cl2, which was dis-
Bond angles
Cl(1)–W(1)–Cl(2)
N(101)–W(1)–C(109)
N(201)–W(1)–C(101)
W(1)–N(201)–C(201)
81.94(5)
39.2(2)
101.96(19)
173.6(6)
1
tilled from CaH2. The H- (300 MHz) and 13C-{1H}-
a The estimated standard deviations of the last significant digits are
shown in parentheses.
(75 MHz) NMR spectra were recorded in benzene-d6
at r.t. unless otherwise indicated. Chemical shifts (in

J.A.M. Brandts et al. / Journal of Organometallic Chemistry 585 (1999) 93–99
97
ppm) are referenced to Me4Si. Commercially available
reagents were distilled prior to use. Elemental analyses
were carried out by Dornis und Kolbe, Mikroanalytis-
ches Laboratorium, Mu¨lheim a.d. Ruhr, Germany.
The compounds WOCl4 [7]; [W(NPh)Cl4(Et2O)] [7];
[W(NPh)(CH2SiMe3)3Cl] [7]; [Li(C6H3(CH2NMe2)2-
2,6)]2 (1) [6]; [Li(CH2{C6H(CH2NMe2)2-2,6-Me2-3,5})]
(3) [6]; [Me3SiCH2(C6H(CH2NMe2)2-2,6-Me2-3,5)] (5)
[6] and LiCH2SiMe3 [14] were synthesized according to
literature procedures.
was removed and the residual solids were washed with
Et2O (2×40 ml) and pentane (2×50 ml) and dried in
vacuo (3 h, 60°C) leaving behind a yellow solid which
was analysed as compound 6 (1.34 g, 2.56 mmol, 95%).
Crystals suitable for X-ray analysis were grown in
several weeks by putting a pentane layer on a CH2Cl2
solution of 6. 1H-NMR (l, CDCl3): 7.34 (m, 8H,
2
Ar–H), 5.32 (d, 1H, CHAHBN, JH
=13.8 Hz), 5.10
H
A
B
(d, 1H, CHAHBN, 2JH
=13.8 Hz), 4.79 (d, 1H,
=13.6 Hz), 4.06 (d, 1H,
=13.6 Hz), 3.62 (d, 1H, CHAHBN,
=5.2 Hz), 3.43 (d, 1H, CHAHBN, JH
H
A
B
WCHAHBN, 2JH
H
A
B
2
WCHAHBN, JH
H
A
B
2
3.1. In situ preparation of ‘Zn(C6H3(CH2NMe2)2-2,6)2’
(2)
2JH
=5.2
H
B
H
A
A
B
Hz), 3.26 (s, 3H, NMe), 3.13 (s, 3H, NMe), 2.84 (s, 3H,
NMe),. 13C-NMR (d, CD2Cl2): 191 (Cipso), 153.7
(Cipso NAr), 144.8, 130.6, 130.0, 129.8, 128.6, 124.5
(aryl-C), 78.1, 78.0 (CH2N), 76.1 (WCH2), 60.3, 54.8,
53.9 (NMe). Tmelt\210°C. Anal. Calc. for
C18H23N3WCl2: C, 40.08 (40.32); H, 4.44 (4.32); N, 7.70
(7.84).
To a solution of [Li(C6H3(CH2NMe2)2-2,6)]2 (1.07 g,
5.40 mmol) in Et2O (50 ml) was added ZnCl2 (0.37 g,
2.70 mmol) as a solid at once at r.t. After 2 h the
suspension was centrifuged and the clear upper layer
was separated from the white precipitate by decantation
and was used as such.
3.4. [W(CH2SiMe3)(NPh){C6H3(ꢀCHNMeCH2)-
2-(CH2NMe2)-6}] (7)
3.2. [Zn(CH2(C6H(CH2NMe2)2-2,6-Me2-3,5))2] (4)
To a solution of ZnCl2 (1.27 g, 9.20 mmol) in Et2O
(50 ml) was added a suspension of [Li(CH2{C6H-
(CH2NMe2)2-2,6-Me2-3,5})] (4.45 g, 18.52 mmol) in
Et2O (50 ml) at −78°C. The reaction mixture was
allowed to warm to r.t. and was stirred overnight. After
18 h, all volatiles were removed in vacuo. The residual
white solid was extracted with pentane (2×100 ml) and
the pentane layers were collected after centrifugation.
All volatiles were removed in vacuo leaving a white
solid (compound 4; yield: 4.68 g (8.80 mmol, yield:
95%)) which was pure by NMR and elemental analysis.
1H-NMR (l): 6.58 (s, 1H, Ph-Hp), 3.40 (s, 4H, CH2N),
2.30 (s, 6H, Me), 1.98 (s, 12H, NMe2), 1.85 (s, 2H,
ZnCH2). 13C NMR (l): 138.0, 133.1, 132.4 (C–Ph),
129.3 (Cipso), 59.4 (CH2N), 45.9 (NMe2), 19.8 (Me),
To a solution of 6 (0.30 g, 0.56 mmol) in THF (30
ml) was slowly added a solution of LiCH2SiMe3 (0.11
g, 1.12 mmol) in THF (10 ml) at −78 °C. After the
addition was completed the solution was slowly (1 h)
warmed to 0 °C. After 2 h all volatiles were removed in
vacuo leaving behind a sticky yellow/orange material
which was extracted with pentane (2 × 20 ml). The
pentane layers were centrifuged and the clear upper
layer was collected. All volatiles were removed in vacuo
leaving behind (0.19 g, 0.35 mmol, 62%) of a yellow
sticky solid, which slowly decomposes at r.t. yielding
paramagnetic compounds and [C6H4(CH2NMe2)2-2,6].
2
1H-NMR (l, C6D6): 9.74 (s, 1H, WꢀCH, JW–H=42.3
Hz), 7.34–6.85 (m, 8H, Ar–H), 4.30 (d, 1H, CHAHBN,
2
2JH
=21.0 Hz), 4.21 (d, 1H, CHAHBN, JH
=9.1
H
A
H
A
B
18.9 (ZnCH2).
Tdecomp=103°C. Anal. Calc. for
2
Hz), 3.86 (d, 1H, WCHAHBN, JH
=21.0 HzB), 3.03
H
A
B
C30H50N4Zn: C, 67.22 (67.71); H, 9.35 (9.47); N, 10.50
(10.53).
(d, 1H, WCHAHBN, 2JH
=9.1 Hz), 2.80 (s, 3H,
H
A
NMe), 2.69 (s, 3H, NMe), 1B.71 (s, 3H, NMe), 0.36 (s,
2
9H, SiMe3), 0.18 (d, 1H, CHAHBSi, JH
−0.18 (d, 1H, CHAHBSi, JH
=6.0 Hz),
H
A
B
3.3. [WCl2(NPh)(C6H3{CH2N(Me)CH2}-2-{CH2-
NMe2}-6)] (6)
2
=6.0 Hz).
H
A
B
A solution of 2 (5.40 mmol) in Et2O (50 ml) was
added over a period of 90 min to a CH2Cl2 (50 ml)
solution of [W(NPh)Cl4(Et2O)] (1.31 g; 2.70 mmol) at
r.t. After 18 h a yellowish precipitate was formed and
was removed by centrifugation. The residual, clear or-
ange solution was collected and all volatiles were re-
moved in vacuo. The brown/yellow solid was extracted
with THF (2×80 ml) and the clear solutions were
collected after centrifugation. The THF layers were
concentrated to 20 ml and upon addition of pentane (60
ml) a yellow precipitate appeared. The clear upper layer
3.5. Structure determination and refinement of 6
X-ray data were collected on an Enraf–Nonius
CAD4-T rotating anode diffractometer for a transpar-
ent, yellowish crystal glued on top of a glass fibre
placed in a stream of N2 at 150 K. Accurate unit-cell
parameters and an orientation matrix were determined
by least-squares refinement of the setting angles of a set
of 25 well-centered reflections (SET4) [15]. The unit-cell
parameters were checked for the presence of higher
lattice symmetry. Data were corrected for Lorentz po-

98
J.A.M. Brandts et al. / Journal of Organometallic Chemistry 585 (1999) 93–99
Table 3
in Table 3, final coordinates and equivalent isotropic
thermal parameters of the non-hydrogen atoms for 6
are given in Table 4. Selected geometrical details of the
structure are listed in Table 2.
Experimental data for the X-ray diffraction study of 6
6
Formula
C18H23N3Cl2W(CH2Cl2)
Formula weight
Temperature (K)
Crystal system
Space group
621.09
150
Monoclinic
P21/c
12.0819(7)
12.8782(7)
16.1180(7)
118.673(4)
2200.3(2)
4. Supplementary material
Crystallographic data for the structural analysis have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC No. 113892 for compound 6.
Copies of this information may be obtained free of
charge from The Director, CCDC, 12, Union Road,
Cambridge CB2 1EZ (Fax: +44-1223-0336033 or e-
mail: deposit@ccdc.cam.ac.uk or http://www.ccdc.
cam.ac.uk).
,
a (A)
,
b (A)
,
c (A)
i (°)
3
,
Volume (A )
Z
4
dcalc. (g cm−3
)
1.875
1208
60.54
0.15 × 0.18 × 0.40
Mo–Ka (0.71073) a
1.9, 27.5
F(000) (electrons)
v (Mo–Ka) (cm−1
Crystal size (mm)
)
,
Radiation (A)
q
min, qmax (°)
Scan (ꢀ-mode) (°)
h, k, l (min, max)
Total/unique reflections
Observed reflections
Nref, Npar
0.54 + 0.35 tan(q)
−15, 9; −16, 16; −18, 20
10 554, 5047
3958(I\2.0|(I))
5047, 221
0.0344; 0.0774; 1.03
|2(F2o)+(0.0353P)2+1.81P
−1.96, 2.12
Acknowledgements
J.A.M.B. gratefully acknowledges financial support
by Dutch Technology Foundation (STW) with financial
aid from the Council for Chemical Science of the
Netherlands/Organization for Scientific Research
(NWO/CW). Dr G.J.M. Gruter (DSM Research), Dr
b
R; wR; S
c
Weight (w−1
)
−3
,
Min., max. resd. dens. (e A
)
a Graphite monochromated.
b R=S ꢀꢀ Fo ꢀ−ꢀ Fc ꢀꢀ/S ꢀ Fo ꢀ. wR2={S [w(F2o−Fc2)2]/S [w(F2o)2]}
c P=(max(Fo2, 0)+2F2c)/3.
.
1/2
Table 4
Final coordinates and equivalent isotropic thermal parameters of the
non-hydrogen atoms for 6
larisation effects. An empirical absorption correction
was applied (PLATON DELABS) [16]. The structure was
2
a
,
Atom
x
y
z
Ueq (A )
/
solved by Direct methods and subsequent difference
Fourier techniques (SHELXS86) [17]. The structure was
found to contain voids filled with disordered CH2Cl2.
Their contribution to the structure factors in the least
squares refinement was taken into account by back-
W(1)
Cl(1)
Cl(2)
0.23858(2)
0.27789(13)
0.06416(14)
0.30092(2)
0.48026(10)
0.38762(11)
0.1905(4)
0.3450(4)
0.2482(3)
0.1888(4)
0.1794(4)
0.1794(4)
0.1104(5)
0.0510(5)
0.0597(5)
0.1291(4)
0.1538(5)
0.1010(5)
0.2872(5)
0.2452(5)
0.3903(5)
0.4178(5)
0.2176(4)
0.1124(4)
0.837(5)
0.35704(1)
0.41675(9)
0.21471(10)
0.3581(3)
0.2981(3)
0.4575(3)
0.2532(3)
0.2167(4)
0.2167(4)
0.1417(4)
0.1073(4)
0.1434(4)
0.2173(4)
0.2602(4)
0.4226(4)
0.3972(4)
0.2652(4)
0.3701(4)
0.2165(4)
0.5405(4)
0.5644(4)
0.6463(4)
0.7046(5)
0.6807(5)
0.5991(4)
0.0247(1)
0.0338(4)
0.0463(4)
N(101) 0.1067(4)
N(102) 0.3775(5)
N(201) 0.3652(4)
C(101) 0.2098(5)
C(102) 0.2918(6)
C(102) 0.2918(6)
C(103) 0.2640(7)
C(104) 0.1555(7)
C(105) 0.0733(6)
C(106) 0.1001(6)
C(107) 0.0168(5)
C(108) 0.1559(6)
C(109) 0.0924(5)
C(110) 0.4078(6)
C(111) 0.4986(5)
C(112) 0.3228(7)
C(201) 0.4707(5)
C(202) 0.4957(5)
C(203) 0.6012(6)
C(204) 0.6848(6)
C(205) 0.6597(6)
C(206) 0.5543(5)
0.0361(14)
0.0339(14)
0.0256(12)
0.0307(16)
0.0362(17)
0.0362(17)
0.0440(19)
0.049(2)
0.0459(19)
0.0372(19)
0.0397(17)
0.046(2)
0.0415(19)
0.0395(19)
0.0418(17)
0.048(2)
0.0274(14)
0.0369(17)
0.047(2)
fourier transformation using PLATON/SQUEEZE [16].
Refinement on F2 was carried out by full-matrix least-
squares techniques (SHELXL93) [18] using no obser-
vance criterion. Hydrogen atoms were included on
calculated positions, riding on their carrier atoms. All
non-hydrogen atoms were refined with anisotropic
atomic displacement parameters. All hydrogen atoms
were refined with a fixed isotropic atomic displacement
parameter related to the value of the equivalent
isotropic atomic displacement parameter of their carrier
atom. Weights were optimized in the final refinement
cycles. Neutral atom scattering factors and anomalous
dispersion corrections were taken from the Interna-
tional Tables for Crystallography [19]. Geometrical cal-
culations and illustrations were performed with PLATON
[16]. All calculations were performed on a DECstation
5000 cluster. Crystal data and numerical details of the
structure determinations and refinements are collected
0.1601(6)
0.2622(6)
0.2924(4)
0.053(2)
0.051(2)
0.0360(17)
a Ueq is one-third of the trace of the orthogonalized U tensor.

J.A.M. Brandts et al. / Journal of Organometallic Chemistry 585 (1999) 93–99
99
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[5] This monoanionic, potentially terdentate diaminoaryl ligand
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.
.