Molybdenum and tungsten complexes that contain the diamidoamine ligands [(C6F5NCH2CH2)2NMe]2 -,[(3,4,5-C6H2F3NCH2 CH2)2NMe]2-, and [(3-CF3 C6H4NCH2CH2)2 NMe]2-

Article abstract of DOI:10.1021/om030638u

Molybdenum and tungsten complexes have been prepared that contain three different types of diamidoamine ligands of the type [(ArNCH₂CH₂)₂NMe]^2- ([ArNMe]^2-, where Ar = C₆F₅, 3,4,5-F₃C₆H₂, 3-CF₃C₆H₄). The starting materials, which are of the type [Et₃NH]{[ArNMe]MCl₃}, are prepared from MCl₄ reagents and the ligand upon addition of triethylamine. X-ray studies for [Et₃NH]{[C₆F₅NMe]MoCl₃}, [Et₃NH]{[C₆F₅NMe]WCl₃}, and [Bu₄N]{[3-CF₃C₆H₄NMe] MoCl₃} reveal that the amido nitrogens are approximately cis to one another in a distorted-pseudooctahedral environment. Addition of various alkylating reagents to various [Et₃NH]{[ArNMe]MCl₃} species led to the formation of [C₆F₅NMe]MoMe₂ (3), [C₆F₅NMe]Mo(CH₂CMe₃)Cl (4b), [C₆F₅NMe]W(CH₂CMe₃)Cl (5), [3,4,5-F₃C₆H₂NMe]Mo(CH₂ CMe₃)Cl (8), [3,4,5-F₃C₆H₂NMe] Mo(CH₂CMe₃) (9), [3,4,5-F₃C₆ H₂NMe]Mo(CH₂SiMe₃)₂ (10), [3,4,5- F₃C₆H₂NMe]W(CH₂CMe₃) (CCMe₃) (11a), [3,4,5-F₃C₆H₂NMe] W(CH₂SiMe₃)(CSiMe₃) (11b), [3-CF₃ C₆H₄NMe]Mo(CH₂SiMe₃)₂ (13), [3-CF₃C₆H₄NMe]Mo(CH₂ CMe₃)Cl (14), and [3-CF₃C₆H₄NMe] Mo(CCMe₃)(CH₂CMe₃) (15). All M⁴⁺ complexes are paramagnetic with magnetic moments that are expected for high-spin d² complexes. X-ray studies of 3, 4b, and 9 show them to be trigonal-bipyramidal species in which the amido nitrogens occupy equatorial positions. The alkylidyne complexes form via elimination of dihydrogen, an α,α-dehydrogenation reaction, as shown by measuring the dihydrogen evolved in one case.

Full text of DOI:10.1021/om030638u

Organometallics 2004, 23, 665-678
665
Molybd en u m a n d Tu n gsten Com p lexes Th a t Con ta in th e
Dia m id oa m in e Liga n d s [(C6F 5NCH2CH2)2NMe]2-,
[(3,4,5-C6H2F 3NCH2CH2)2NMe]2-, a n d
[(3-CF 3C6H4NCH2CH2)2NMe]2-
Frank V. Cochran, Adam S. Hock, and Richard R. Schrock*
Department of Chemistry, Massachusetts Institute of Technology,
Cambridge, Massachusetts 02139
Received October 20, 2003
Molybdenum and tungsten complexes have been prepared that contain three different
types of diamidoamine ligands of the type [(ArNCH2CH2)2NMe]2- ([ArNMe]2-, where Ar )
C6F5, 3,4,5-F3C6H2, 3-CF3C6H4). The starting materials, which are of the type [Et3NH]-
{[ArNMe]MCl3}, are prepared from MCl4 reagents and the ligand upon addition of
triethylamine. X-ray studies for [Et3NH]{[C6F5NMe]MoCl3}, [Et3NH]{[C6F5NMe]WCl3}, and
[Bu4N]{[3-CF3C6H4NMe]MoCl3} reveal that the amido nitrogens are approximately cis to
one another in a distorted-pseudooctahedral environment. Addition of various alkylating
reagents to various [Et3NH]{[ArNMe]MCl3} species led to the formation of [C6F5NMe]MoMe2
(3), [C6F5NMe]Mo(CH2CMe3)Cl (4b), [C6F5NMe]W(CH2CMe3)Cl (5), [3,4,5-F3C6H2NMe]Mo-
(CH2CMe3)Cl (8), [3,4,5-F3C6H2NMe]Mo(CH2CMe3)(CCMe3) (9), [3,4,5-F3C6H2NMe]Mo(CH2-
SiMe3)2 (10), [3,4,5-F3C6H2NMe]W(CH2CMe3)(CCMe3) (11a ), [3,4,5-F3C6H2NMe]W(CH2-
SiMe3)(CSiMe3) (11b), [3-CF3C6H4NMe]Mo(CH2SiMe3)2 (13), [3-CF3C6H4NMe]Mo(CH2CMe3)Cl
(14), and [3-CF3C6H4NMe]Mo(CCMe3)(CH2CMe3) (15). All M4+ complexes are paramagnetic
with magnetic moments that are expected for high-spin d2 complexes. X-ray studies of 3,
4b, and 9 show them to be trigonal-bipyramidal species in which the amido nitrogens occupy
equatorial positions. The alkylidyne complexes form via elimination of dihydrogen, an “R,R-
dehydrogenation” reaction, as shown by measuring the dihydrogen evolved in one case.
In tr od u ction
the chemistry of d2 Mo and W alkyl complexes.18-21 For
example, molybdenum and tungsten complexes of the
type [(Me3SiNCH2CH2)3N]MCH2R were found to un-
dergo R-elimination reactions that are orders of mag-
nitude faster than â-elimination reactions and R,R-
dehydrogenation reactions that convert a complex of
the type [(Me3SiNCH2CH2)3N]MCH2R into one of the
type [(Me3SiNCH2CH2)3N]MtCR, presumably through
formation of the intermediate species [(Me3SiNCH2-
CH2)3N]M(H)(CHR) followed by loss of molecular hy-
drogen.
Transition-metal complexes that contain amido ligands
have become more numerous and important in coordi-
nation chemistry and in a variety of catalytic reactions
in the past decade.1-4 Over the last several years, we
have been interested in triamidoamine ligands of the
type [(RNCH2CH2)3N]3- or diamido-donor ligands of
the type [(RNCH2CH2)2D]2- (D ) a donor such as O or
NR′) and [H3CC(2-C5H4N)(CH2NR)2]2-.4 Triamidoamine
ligands have been employed primarily for the purpose
of exploring organometallic or dinitrogen chemistry of
Mo and W,5-9 while diamido-donor ligands have been
employed primarily for preparing Zr and Hf catalysts
for the polymerization of ordinary olefins.10-17 Triami-
doamine ligands also have been employed in studies of
We felt that Mo and W complexes containing a
diamido-donor ligand could be synthesized, since in the
(12) Baumann, R.; Stumpf, R.; Davis, W. M.; Liang, L.-C.; Schrock,
R. J . Am. Chem. Soc. 1999, 121, 7822.
(13) Schrock, R. R.; Baumann, R.; Reid, S. M.; Goodman, J . T.;
Stumpf, R.; Davis, W. M. Organometallics 1999, 18, 3649.
(14) Schrock, R. R.; Casado, A. L.; Goodman, J . T.; Liang, L.-C.;
Bonitatebus, P. J ., J r.; Davis, W. M. Organometallics 2000, 19, 5325.
(15) Schrock, R. R.; Bonitatebus, P. J ., J r.; Schrodi, Y. Organome-
tallics 2001, 20, 1056.
(16) Mehrkhodavandi, P.; Bonitatebus, P. J ., J r.; Schrock, R. R. J .
Am. Chem. Soc. 2000, 122, 7841.
(17) Mehrkhodavandi, P.; Schrock, R. R. J . Am. Chem. Soc. 2001,
123, 10746.
(18) Shih, K.-Y.; Totland, K.; Seidel, S. W.; Schrock, R. R. J . Am.
Chem. Soc. 1994, 116, 12103.
(19) Seidel, S. W.; Schrock, R. R.; Davis, W. M. Organometallics
1998, 17, 1058.
(20) Schrock, R. R.; Seidel, S. W.; Mo¨sch-Zanetti, N. C.; Dobbs, D.
A.; Shih, K.-Y.; Davis, W. M. Organometallics 1997, 16, 5195.
(21) Schrock, R. R.; Seidel, S. W.; Mosch-Zanetti, N. C.; Shih, K.-Y.;
O’Donoghue, M. B.; Davis, W. M.; Reiff, W. M. J . Am. Chem. Soc. 1997,
119, 11876.
(1) Kempe, R. Angew. Chem., Int. Ed. 2000, 39, 469.
(2) Britovsek, G. J . P.; Gibson, V. C.; Wass, D. F. Angew. Chem.,
Int. Ed. 1999, 38, 428.
(3) Gade, L. H. Chem. Commun. 2000, 173.
(4) Gade, L. H. Acc. Chem. Res. 2002, 35, 575.
(5) Greco, G. E.; Schrock, R. R. Inorg. Chem. 2001, 40, 3860.
(6) Yandulov, D. V.; Schrock, R. R. Science 2003, 301, 76.
(7) Yandulov, D. V.; Schrock, R. R. J . Am. Chem. Soc. 2002, 124,
6252.
(8) O’Donoghue, M. B.; Davis, W. M.; Schrock, R. R. Inorg. Chem.
1998, 37, 5149.
(9) O’Donoghue, M. B.; Davis, W. M.; Schrock, R. R.; Reiff, W. M.
Inorg. Chem. 1999, 38, 243.
(10) Aizenberg, M.; Turculet, L.; Davis, W. M.; Schattenmann, F.;
Schrock, R. R. Organometallics 1998, 17, 4795.
(11) Schrock, R. R.; Seidel, S. W.; Schrodi, Y.; Davis, W. M.
Organometallics 1999, 18, 428.
10.1021/om030638u CCC: $27.50 © 2004 American Chemical Society
Publication on Web 01/20/2004

666 Organometallics, Vol. 23, No. 4, 2004
Cochran et al.
process of exploring the dinitrogen chemistry of [(Me3-
SiNCH2CH2)3N]Mo complexes a compound was formed
as a consequence of degradation of the [(Me3SiNCH2-
CH2)3N]3- ligand, in which a free dimethylamine arm
was not coordinated to molybdenum;8 the ligand was
effectively a diamido-donor ligand. The desire to ex-
plore further the Mo or W chemistry of d2 alkyl
complexes in amido ligand environments gave rise to
the work reported here, which involves diamido-donor
ligands of the type [(RNCH2CH2)2NMe]2-, where R )
C6F5, 3,4,5-C6H2F3, 3-CF3C6H4. Some of the results
reported here have appeared in preliminary form22,23
and should be compared with several analogous molyb-
denum complexes in which the ligand is [(3,5-Cl2C6H3-
contains an adduct between H2[F5NMe] and MoCl4.
Attempts to isolate or identify this adduct were not
successful. Addition of 2 equiv of NEt3 caused the
solution to deepen in color rapidly and an off-white
precipitate of [Et3NH]Cl to form. Paramagnetic [Et3NH]-
{[F5NMe]MoCl3} (1a ) was isolated as a burgundy pow-
der in 83% yield upon filtering the reaction mixture and
adding pentane to the filtrate (eq 2). The 19F NMR
NCH2CH2)2NMe]2- 24
.
Resu lts
Syn t h esis a n d Ch a r a ct er iza t ion of {[F 5NMe]-
MCl3}- Sp ecies (M ) Mo, W). The reaction between
(H2NCH2CH2)2NH and hexafluorobenzene in the pres-
ence of K2CO3 in refluxing acetonitrile has been reported
to give (C6F5NHCH2CH2)2NH in 40% yield.25 The yield
was raised to 60% by flash-filtering a concentrated
solution of the product mixture in ether through acti-
vated alumina, thereby removing monoarylated mate-
rial. Approximately 18 g of pure (C6F5NHCH2CH2)2NH
could be obtained readily in this manner.
Replacement of the proton on the central amine
nitrogen with an alkyl group was desirable in order to
block formation of any complexes that contain the
trianionic ligand25 [(C6F5NCH2CH2)2N]3- and also in
order to create more steric protection near the metal.
Methylation of (C6F5NHCH2CH2)2NH in acetonitrile
with methyl iodide in the presence of K2CO3 gave (C6F5-
NHCH2CH2)2NMe (H2[F5NMe]) in 63% yield on a 6-7
g scale (eq 1). After standard workup, H2[F5NMe] was
spectrum of 1a in THF contained five resonances of
equal intensity at -95.46, -119.25, -131.27, -134.95,
and -169.26 ppm. Five shifted resonances are charac-
teristic of a paramagnetic metal complex in which the
pentafluorophenyl rings do not rotate rapidly on the
NMR time scale.
The tetrabutylammonium analogue [Bu4N]{[F5NMe]-
MoCl3} (1b) was prepared in 98% yield by reacting 1a
with Bu4NCl in THF (eq 3). The Et3NHCl was filtered
extracted into chloroform and any insoluble ammonium
salt formed by double methylation at the central nitro-
gen was removed by filtration. A slight excess (1.3 equiv)
of MeI was required in order to consume all starting
material as a consequence of over-methylation of the
central amine nitrogen. Methylation did not seem to
work as well on a large scale. Therefore, we could not
prepare H2[F5NMe] on a scale of more than 6-7 g at a
time. Methylation of the central amine nitrogen has
been employed in order to synthesize other triamines
of this general type.14,15,24
off and 1b isolated by precipitation with pentane.
Complex 1b displayed much greater solubility in ben-
zene and toluene than 1a .
The 19F NMR spectrum of 1b in C6D6 (Figure 1) is
similar to that of 1a with five broad resonances of about
equal intensity at -92.54, -115.76, -128.40, -133.75,
and -168.07 ppm. The resonances are assigned as
shown in Figure 1 on the basis of their breadth: i.e.,
the ortho fluorines, which are closest to the paramag-
netic metal center, are the broadest. The 1H NMR
spectrum of complex 1b in C6D6 (Figure 2) showed
resonances for the ligand backbone that are shifted
upfield to a degree found for the triamidoamine ligand
backbone in paramagnetic d2 complexes of molybde-
Addition of orange MoCl4(THF)2 to a stirred solution
of H2[F5NMe] dissolved in THF produced a deep red,
homogeneous solution in several seconds that we believe
(22) Cochran, F. V.; Bonitatebus, P. J .; Schrock, R. R. Organome-
tallics 2000, 19, 2414.
(23) Cochran, F. V.; Schrock, R. R. Organometallics 2001, 20, 2127.
(24) Araujo, J . P.; Wicht, D. K.; Bonitatebus, P. J ., J r.; Schrock, R.
R. Organometallics 2001, 20, 5682.
(25) Schrock, R. R.; Lee, J .; Liang, L.-C.; Davis, W. M. Inorg. Chim.
Acta 1998, 270, 353.

Mo and W Diamidoamine Complexes
Organometallics, Vol. 23, No. 4, 2004 667
F igu r e 3. Thermal ellipsoid plot (35% probability level)
of the anion structure of [Et3NH]{[F5NMe]MoCl3} (1a ).
Hydrogens have been omitted for clarity.
F igu r e 1. 19F NMR spectrum (282 MHz, C6D6) of
[Bu4N]{[F5NMe]MoCl3}.
rings on the NMR time scale can be attributed to
interactions between an ortho fluoride and the apical
chloride (1.3-1.4 Å away when the C6F5 ring is rotated,
so as to lie approximately in the N(1) or N(3) plane) and
between an ortho fluoride and the methylene protons
next to N(1) and N(3). The cation is oriented toward a
{[F5NMe]MoCl3}- ion in an adjacent asymmetric unit.
The triethylammonium proton approaches the trichlo-
ride face of the octahedron. The closest contact is to the
chloride trans to the Namine donor at a distance of 2.27
Å.
Tungsten complexes analogous to 1a and 1b could be
prepared from WCl4(dme).29 The reaction between (C6F5-
NHCH2CH2)2NMe, WCl4(dme), and 2 equiv of NEt3 was
carried out in diethyl ether instead of THF in order to
avoid formation of relatively insoluble and unreactive
WCl4(THF)2. The ether was removed in vacuo, and [Et3-
NH]{[F5NMe]WCl3} (2a ) was extracted into THF, from
which it could be crystallized in 60% yield. Cation
exchange was accomplished by salt metathesis of 2a
with Bu4NCl in THF to give [Bu4N]{[F5NMe]WCl3} (2b)
as a light green powder in good yield. Fluorine and
proton NMR spectra of 2a and 2b are similar to those
for 1a and 1b, except the resonances are much sharper
in the tungsten compounds as a consequence of greater
spin-orbit coupling for tungsten. A magnetic moment
of 2.7 µB was found for 2b in C6D6 by the Evans method,
consistent with two unpaired electrons.
Large dark green crystals of 2a were grown from a
THF solution layered with pentane. Crystallographic
data, collection parameters, and refinement parameters
can be found in Table 1, while selected bond lengths (Å)
and angles (deg) are given in Table 2. A thermal
ellipsoid plot of the anion structure is shown in Figure
4. As opposed to 1a , the triethylammonium cation
approaches the trichloride face of the pseudooctahedron
with the H-Cl distances to Cl(1), Cl(2), and Cl(3) being
longer (2.99, 2.73, and 2.77 Å, respectively). The core
structure of the molecule is not significantly different
from 1a and warrants no discussion.
F igu r e 2. 1H NMR spectrum (300 MHz, C6D6) of [Bu4N]-
{[F5NMe]MoCl3}.
num.26 The resonances near 1 ppm are assigned to the
tetrabutylammonium cation, while the resonances at
-4.15, -29.98, -123.84, and -149.7 ppm are assigned
to the four types of CH2 protons in the backbone of the
[F5NMe]2- ligand. The resonance at 18.82 ppm is
assigned to the methyl group on the central donor
nitrogen. The magnetic susceptibility of 1b in C6D6 at
22 °C was determined by the Evans method27 as
modified by Sur28 to be 3.1 µB, which is consistent with
the molybdenum having two unpaired electrons. This
value is essentially identical with several other experi-
mentally determined magnetic moments of related d2
Mo complexes in this work.
Complex 1a crystallized as dark red blocks from
toluene solution at -30 °C in the monoclinic space group
P21/c. Crystallographic data, collection parameters, and
refinement parameters can be found in Table 1, while
selected bond lengths (Å) and angles (deg) are listed in
Table 2. The anion (Figure 3) is a distorted-octahedral
species in which the [F5NMe]2- ligand is bound in a
facial manner. All Mo-N bond lengths and angles are
similar to those in an analogous species that contains
the [(3,5-Cl2C6H3NCH2CH2)2NMe]2- ligand.24 The Mo-
F
ortho distances (3.7-4.2 Å) are long enough to rule out
any significant interaction between the ortho fluorides
and the molybdenum, the closest approach of two ortho
fluorides being 2.84 Å. Restricted rotation of the C6F5
Or gan om etallic Com plexes of Molybden u m Th at
Con ta in th e [F 5NMe]2- Liga n d . Addition of 3 equiv
of MeMgCl to a dark red solution of [Et3NH]{[F5NMe]-
MoCl3} (1a ) in THF resulted in a color change from dark
(26) Greco, G. E.; Schrock, R. R. Inorg. Chem. 2001, 40, 3850.
(27) Evans, D. F. J . Chem. Soc. 1959, 2003.
(28) Sur, S. K. J . Magn. Reson. 1989, 82, 169.
(29) Persson, C.; Andersson, C. Inorg. Chim. Acta 1993, 203, 235.

668 Organometallics, Vol. 23, No. 4, 2004
Cochran et al.
Ta ble 1. Cr ysta llogr a p h ic Da ta , Collection P a r a m eter s, a n d Refin em en t P a r a m eter s for
[Et3NH]{[F 5NMe]MoCl3} (1a ), [Et3NH]{[F 5NMe]WCl3} (2a ), a n d [Bu 4N]{[CF 3NMe]MoCl3} (12b)a
1a b
2a c
12b
empirical formula
formula wt
cryst syst
space group
unit cell dimens
a (Å)
C
23H27N4Cl3F10Mo
C23H27N4Cl3F10
733.33
monoclinic
C2/c
W
C35H55N4MoCl3F6
848.12
triclinic
751.78
monoclinic
P21/c
P1h
11.811(3)
17.123(4)
17.325(4)
90
95.233(4)
90
3489.2(13)
4
19.8048(3)
11.48880(10)
27.8998(5)
90
92.8030(10)
90
6340.54(16)
8
1.759
10.631(6)
14.548(7)
15.045(8)
64.132(9)
78.308(9)
85.861(11)
2049.9(18)
2
b (Å)
c (Å)
R (deg)
â (deg)
γ (deg)
V (Å3)
Z
calcd density (Mg/m3)
1.605
0.687
1.374
0.572
abs coeff (mm-1
)
3.976
F(000)
1700
3264
880
θ range for data collecn (deg)
1.68-19.99
2.05-22.50
1.53-22.50
index ranges
-11 e h e 9, -16 e k e 16,
-16 e l e 14
10 314
-21 e h e 21, -12 e k e 9,
-21 e l e 30
-11 e h e 9, -15 e k e 15,
-16 e l e 16
no. of rflns collected
no. of indep rflns
abs cor
11 573
4141 (Rint ) 0.0976)
none
8724
3256 (Rint ) 0.1596)
empirical
5343 (Rint ) 0.1326)
none
no. of data/restraints/params
goodness of fit on F2
final R indices (I > 2σ(I))
R indices (all data)
3256/0/429
1.127
R1 ) 0.0612, wR2 ) 0.1517
R1 ) 0.0807, wR2 ) 0.1833
0.929 and -1.350
4141/0/371
1.074
R1 ) 0.0403, wR2 ) 0.1003
R1 ) 0.0453, wR2 ) 0.1033
0.787 and -1.883
5343/0/448
1.202
R1 ) 0.0788, wR2 ) 0.2201
R1 ) 0.1038, wR2 ) 0.2640
1.421 and -2.591
largest diff peak and hole (e Å-3
)
a
b
Conditions: wavelength, 0.710 73 Å; refinement by full-matrix least squares on F2; temperature, 183(2) K. One molecule of toluene
was present per molybdenum. c Excess electron density due to a highly disordered THF molecule was found in voids (a total of 230 electrons
per unit cell). It was “removed” using the program SQUEEZE.51
Ta ble 2. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for th e An ion s in [Et3NH][F 5NMe]MoCl3 (1a ),
[Et3NH]{[F 5NMe]WCl3} (2a ), a n d
[Bu 4N]{[CF 3NMe]MoCl3} (12b)
1a
2a
12b
M-N(1)
M-N(2)
M-N(3)
M-Cl(1)
M-Cl(2)
M-Cl(3)
1.991(8)
2.216(8)
2.019(9)
2.410(3)
2.514(3)
2.480(3)
1.996(6)
2.230(6)
2.010(6)
2.4010(18)
2.4505(19)
2.4845(19)
2.003(8)
2.250(8)
1.995(9)
2.377(3)
2.446(3)
2.496(3)
N(1)-M-N(2)
N(1)-M-N(3)
N(1)-M-Cl(1)
N(1)-M-Cl(2)
N(1)-M-Cl(3)
N(2)-M-Cl(1)
N(2)-M-Cl(2)
N(2)-M-Cl(3)
Cl(1)-M-Cl(2)
Cl(2)-M-Cl(3)
77.9(3)
102.9(3)
94.6(2)
78.2(2)
100.3(2)
81.0(3)
96.2(3)
97.3(2)
89.7(3)
169.2(3)
172.9(3)
93.2(3)
90.1(2)
92.29(10)
84.67(11)
97.60(18)
92.13(19)
170.82(19)
174.80(18)
90.59(19)
94.54(18)
92.67(7)
86.8(2)
167.8(2)
171.5(2)
87.7(2)
98.1(2)
96.11(9)
81.56(10)
F igu r e 4. Thermal ellipsoid plot (35% probability level)
of the anion structure of [Et3NH]{[F5NMe]WCl3} (2a ).
Hydrogens have been omitted for clarity.
82.21(7)
quence of the proximity of these protons to the para-
magnetic metal center. The magnetic susceptibility of
3 in solution (Evans method) was found to be 3.1 µB.
Compound 3 crystallized from ether in the monoclinic
space group P21/n. Crystallographic data, collection
parameters, and refinement parameters are given in
Table 3, while selected bond lengths (Å) and angles (deg)
can be found in Table 4. Compound 3 was found to be
approximately a trigonal bipyramid, as shown in Figure
5. The C(1)-Mo-N(2) bond angle is 171.4(2)°, while
N(1)-Mo-N(3) ) 123.3(2)° and C(2)-Mo-N(3) ) 114.9-
(2)°. The Mo-Cax bond length (2.269(4) Å) is signifi-
cantly longer than the Mo-Ceq bond length (2.134(6) Å).
The metal-amido and metal-amine bond lengths are
in the expected range.
red to green. Green paramagnetic [F5NMe]MoMe2 (3)
was isolated in 50% yield (eq 4) after recrystallization
from diethyl ether and pentane. The 19F and H NMR
1
spectra of 3 in THF are analogous to those of 1a and
other d2 compounds in this category. As expected,
resonances corresponding to the methyl groups directly
bound to the metal could not be located, as a conse-
Addition of 1 equiv of 2,6-lutidinium chloride to 3 in
diethyl ether yielded light green, paramagnetic [F5-
NMe]MoMeCl (4a ), which could be isolated in 47% yield

Mo and W Diamidoamine Complexes
Organometallics, Vol. 23, No. 4, 2004 669
Ta ble 3. Cr ysta llogr a p h ic Da ta , Collection P a r a m eter s, a n d Refin em en t P a r a m eter s for [F 5NMe]MoMe2 (3),
[F 5NMe]Mo(CH2CMe3)Cl (4b), a n d [F 3NMe]Mo(CH2CMe3)(CCMe3) (9)
3
4b
9
empirical formula
formula wt
cryst syst
space group
unit cell dimens
a (Å)
C
19H17N3F10Mo
C22H22N3ClF10Mo
649.81
orthorhombic
Pna21
C27H35N3F6Mo
611.52
monoclinic
P21/n
573.29
monoclinic
P21/n
11.7234(4)
14.8706(16)
12.5977(9)
b (Å)
12.0802(4)
10.3947(11)
14.7520(11)
c (Å)
16.2635(5)
15.9370(17)
15.0992(11)
R (deg)
90
90
90
90
90
â (deg)
110.599 (1)
90
2156.0(1)
98.1530(10)
90
2777.7(4)
γ (deg)
V (Å3)
2463.5(5)
Z
2
4
4
calcd density (Mg/m3)
1.769
0.706
1.752
0.735
1.462
0.533
abs coeff (mm-1
)
F(000)
1139
1292
1256
cryst size (mm3)
0.5 × 0.3 × 0.2
3.74-26.58
-13 e h e 12, -13 e k e 8,
-14 e l e 18
8595
0.2 × 0.1 × 0.1
0.2 × 0.2 × 0.2
θ range for data collecn (deg)
index ranges
2.34-22.50
2.66-23.28
-15 e h e 16, -16 e k e 11,
-10 e l e 17
8843
-10 e h e 14, -16 e k e 16,
-16 e l e 16
10 874
no. of rflns collected
no. of indep rflns
completeness to θmax (%)
abs cor
3098 (Rint ) 0.0395)
2838 (Rint ) 0.0383)
99.8
none
3983 (Rint ) 0.0390)
99.5
none
empirical
max and min transmissn
no. of data/restraints/params
goodness of fit on F2
final R indices (I > 2σ(I))
R indices (all data)
0.4139 and 0.3262
3096/0/328
1.222
R1 ) 0.0457, wR2 ) 0.1108
R1 ) 0.0496, wR2 ) 0.1127
0.666 and -0.352
2838/1/340
1.080
R1 ) 0.0310, wR2 ) 0.0769
R1 ) 0.0409, wR2 ) 0.0821
0.386 and -0.400
3983/0/362
0.943
R1 ) 0.0294, wR2 ) 0.0770
R1 ) 0.0374, wR2 ) 0.0812
0.337 and -0.526
largest diff peak and hole (e Å-3
)
a
Conditions: wavelength, 0.710 73 Å; refinement by full-matrix least squares on F2; temperature 183(2) K.
Ta ble 4. Selected Bon d Len gth s (Å) a n d An gles (d eg) for [F 5NMe]MoMe2 (3), [F 5NMe]Mo(CH2CMe3)Cl (4b),
a n d [F 3NMe]Mo(CCMe3)(CH2CMe3) (9)
3
4b
9
Mo-N(1)
1.970(4)
2.325(4)
1.957(4)
2.269(4)
2.134(6)
78.4(2)
123.3(2)
98.9(2)
118.8(2)
171.4(2)
96.7(2)
Mo-N(1)
1.974(3)
2.254(4)
1.974(3)
2.3847(14)
2.141(6)
79.67(10)
126.01(19)
94.50(9)
114.75(10)
166.69(12)
90.52(19)
102.79(16)
130.1(4)
Mo-N(1)
2.042(2)
2.392(2)
1.966(2)
1.776(3)
2.143(3)
75.42(9)
126.43(9)
101.19(10)
112.67(11)
170.66(10)
88.54(11)
100.78(12)
173.0(2)
Mo-N(2)
Mo-N(2)
Mo-N(2)
Mo-N(3)
Mo-N(1A)
Mo-N(3)
Mo-C(1)
Mo-Cl(1)
Mo-C(1)
Mo-C(2)
Mo-C(1)
Mo-C(6)
N(1)-Mo-N(2)
N(1)-Mo-N(3)
N(1)-Mo-C(1)
N(1)-Mo-C(2)
N(2)-Mo-C(1)
N(2)-Mo-C(2)
C(1)-Mo-C(2)
N(1)-Mo-N(2)
N(1)-Mo-N(1a)
N(1)-Mo-Cl(1)
N(1)-Mo-C(1)
N(2)-Mo-Cl(1)
N(2)-Mo-C(1)
C(1)-Mo-Cl(1)
Mo-C(1)-C(2)
N(1)-Mo-N(2)
N(1)-Mo-N(3)
N(1)-Mo-C(1)
N(1)-Mo-C(6)
N(2)-Mo-C(1)
N(2)-Mo-C(6)
C(1)-Mo-C(6)
Mo-C(1)-C(2)
91.7(2)
F igu r e 5. Thermal ellipsoid plot (30% probability level)
of the structure of [F5NMe]MoMe2 (3). Hydrogens have
been omitted for clarity.
in the equatorial plane. However, we do not know
whether the methyl group is in the equatorial position
or the axial position. The 19F NMR spectrum of 4a in
C6D6 is similar to those of other compounds discussed
here, although the 1H NMR spectrum of 4a in C6D6
(eq 5). On the basis of the structure of 3 and related
molecules reported here, we believe that 4a is likely to
be a trigonal bipyramid with the two amido nitrogens

670 Organometallics, Vol. 23, No. 4, 2004
Cochran et al.
solubility in common organic solvents other than THF.
A measurement of the magnetic moment in CD2Cl2 by
the Evans method gave a value of 2.6 µB for µeff, a figure
that is similar to µeff for other d2 W complexes reported
here.
Attempts to force more than one neopentyl group to
add to Mo or W to yield species analogous to 3 or
neopentyl/neopentylidyne species analogous to those
reported below were not successful.
Syn t h esis a n d Ch a r a ct er iza t ion of {[F 3NMe]-
MCl3}- Sp ecies (M ) Mo, W). A report that two
fluorides in pentafluorophenyl rings bound to secondary
amine nitrogens could be replaced upon treatment with
LiAlH4 in refluxing THF30 prompted us to attempt a
similar reaction starting with (C6F5NHCH2CH2)2NMe.
A mixture of (C6F5NHCH2CH2)2NMe and 2 equiv of
LiAlH4 in THF was heated to reflux for 4 h. Standard
workup led to the isolation of (C6H2F3NHCH2CH2)2NMe
(H2[F3NMe]) as a thick yellow oil in 85% yield on a 4-5
g scale (eq 6). Replacement of two fluorine atoms on each
F igu r e 6. Thermal ellipsoid plot (30% probability level)
of the structure of [F5NMe]Mo(CH2CMe3)Cl (4b). Hydro-
gens have been omitted for clarity.
revealed only three very broad resonances for the ligand
CH2 and CH3 groups at 14.3, -54.6, and -84.4 ppm.
As expected, a resonance for the methyl group bound
to the metal could not be located.
Addition of either 2 or 3 equiv of Me3CCH2MgCl to a
THF solution of 1a led to formation of deep green,
paramagnetic [F5NMe]Mo(CH2CMe3)Cl (4b), which could
be isolated in 60% yield. Five resonances of approxi-
mately equal intensity were found in the 19F NMR
spectrum of 4b in CD2Cl2, while in the 1H NMR
spectrum in CD2Cl2 five broadened resonances were
found at 9.5, 6.3, 3.2, -59.6, and -82.8 ppm. The most
intense resonance, at 3.2 ppm, was assigned to the
protons of the CMe3 group. A resonance corresponding
to the methylene protons of the neopentyl group could
not be located. For 4b in CD2Cl2 at room temperature
aryl ring with two hydrogen atoms was consistent with
observation of a multiplet at 5.73 ppm in the H NMR
1
spectrum of (C6H2F3NHCH2CH2)2NMe in C6D6 and two
resonances at -136.3 and -177.8 ppm in a 2:1 ratio in
the 19F NMR spectrum in C6D6. X-ray crystallographic
studies of complexes containing the [F3NMe]2- ligand
(described later) proved that the aryl is a 3,4,5-C6H2F3
ring. Formation of a 2,4,6-C6H2F3 ring was proposed in
the compounds in the original report.30
A deep red, homogeneous solution formed after sev-
eral seconds when orange MoCl4(THF)2 was stirred into
a solution of (C6H2F3NHCH2CH2)2NMe in THF. Sub-
sequent addition of 2 equiv of NEt3 caused the solution
to turn dark purple and an off-white precipitate of Et3-
NHCl to form. Paramagnetic [Et3NH]{[F3NMe]MoCl3}
(6a ) was isolated as a dark purple powder in 87% yield
by filtering the reaction mixture and precipitating the
product with pentane (eq 7). The 19F NMR spectrum of
µ
eff was found to be 3.1 µB (Evans method), as expected.
The solubility of 4b in common solvents other than THF
was surprisingly low, which made isolation of pure
material tedious and which limited the amount of 4b
that could be synthesized and purified readily.
Complex 4b crystallized from THF in the orthorhom-
bic space group Pna21 as dark green blocks. Crystal-
lographic data, collection parameters, and refinement
parameters are given in Table 3, while selected bond
lengths (Å) and angles (deg) are listed in Table 4. As
shown in Figure 6, compound 4b is approximately a
trigonal bipyramid in which the neopentyl group and
the two amido nitrogens of the [F5NMe]2- ligand
comprise the equatorial plane and the chloride is in the
apical site trans to the amine donor. The Cl(1)-Mo-
N(2) angle is only 166.69(12)°, as a consequence of steric
interaction between the apical chloride and the neopen-
tyl’s tert-butyl group, which is forced to point toward
the chloride as a consequence of steric interaction with
the methyl group on the central amine donor. All bond
lengths are in the expected range and are similar to
those found in [(3,5-Cl2C6H3NCH2CH2)2NMe]Mo(CH2-
CMe3)Cl,24 whose structure is analogous to that of 4b.
The low solubility of 4b and similar species remains a
curiosity.
The reaction between [Et3NH]{[F5NMe]WCl3} and
either 2 or 3 equiv of Me3CCH2MgCl in THF led to
green, paramagnetic [F5NMe]W(CH2CMe3)Cl (5) in 45%
yield. Complex 5 is believed to have a structure similar
to that of 4b. Like 4b, 5 also has surprisingly low
6a in THF displayed two resonances in a 2:1 ratio at
(30) Buchler, S.; Meyer, F.; J acobi, A.; Kircher, P.; Zsolnai, L. Z.
Naturforsch. 1999, 54b, 1295.

Mo and W Diamidoamine Complexes
Organometallics, Vol. 23, No. 4, 2004 671
-104.85 and -206.57 ppm, consistent with free rotation
of the C6H2F3 rings about the N-Cipso bond. Complex
6a is believed to have a structure analogous to the
structures of [Et3NH]{[F5NMe]MoCl3} (Figure 3) and
[Et3NH]{[(3,5-C6Cl2H3NCH2CH2)2NMe]MoCl3}.24
The reaction between 6a and tetrabutylammonium
chloride in THF gave the more soluble complex [Bu4N]-
{[F3NMe]MoCl3} (6b) in 90% yield as a purple powder.
The 19F NMR spectrum of 6b in C6D6 displayed two
resonances at -103.89 ppm and -207.48 ppm in a 2:1
ratio assigned to the meta and para fluorines of the
C6H2F3 rings on the [F3NMe]2- ligand, while the 1H
NMR spectrum of 6b in C6D6 displayed resonances
corresponding to the tetrabutylammonium ion at 1.64,
1.21, and 0.97 ppm. Broadened resonances correspond-
1
ing to the [F3NMe]2- ligand in the H NMR spectrum
were found at 28.25, 6.11, -3.84, -29.67, -96.83, and
-99.60 ppm. A measurement of the magnetic moment
of 6b by the Evans method27 as modified by Sur28 in
C6D6 gave µeff ) 3.1 µB.
collection parameters, and refinement parameters for
9 are given in Table 3, and selected bond lengths (Å)
and angles (deg) are listed in Table 4. The structure of
9 is approximately a trigonal bipyramid, with the
neopentylidyne ligand occupying an axial position trans
to the amine donor of the [F3NMe]2- ligand (Figure 7).
The fluorides were found in the 3-, 4-, and 5-positions
of the aryl rings. The two amido nitrogens of the
[F3NMe]2- ligand and the neopentyl group’s methylene
group are found in the equatorial positions. The short
Mo-C(1) bond length (1.776(3) Å) is that expected for
a metal-carbon triple bond.31 The tert-butyl group of
the neopentyl group is turned away from the methyl
group on the central amine donor, which forces the axial
neopentylidyne ligand away from the axial position
slightly (N(2)-Mo-C(1) ) 170.66(10)°).
A reaction between WCl4(dme), H2[F3NMe], and 2
equiv of NEt3 in diethyl ether produced [Et3NH]{[F3-
NMe]WCl3} (7a ) in 86% yield. The more soluble tet-
rabutylammonium analogue [Bu4N]{[F3NMe]WCl3} (7b)
was synthesized by salt metathesis of 7a with Bu4NCl
1
in THF in 78% yield. The 19F and H NMR spectra of
7a and 7b are entirely analogous to those of 6a and 6b,
except that the resonances for 7a and 7b are sharper.
A measurement of the magnetic moment of 6b by the
Evans method27 in C6D6 gave µeff ) 2.7 µB, consistent
with the tungsten center having two unpaired electrons.
Or ga n om eta llic Com p lexes of Molybd en u m a n d
Tu n gst en Th a t Con t a in t h e [F 3NMe]2- Liga n d .
Attempts to prepare and isolate methyl complexes of
molybdenum containing the [F3NMe]2- ligand analo-
gous to [F5NMe]MoMe2 and [F5NMe]MoMeCl were not
successful. However, organometallic derivatives could
be prepared that contain neopentyl and (trimethylsilyl)-
methyl groups. The reaction between [Et3NH]{[F3NMe]-
MoCl3} and 2 equiv of Me3CCH2MgCl in THF led to
green, paramagnetic [F3NMe]Mo(CH2CMe3)Cl (8) in
43% yield. Like other monoalkyl complexes of this type,
8 was only sparingly soluble in common organic sol-
vents, with the exception of THF. The structure of 8 is
believed to be approximately trigonal bipyramidal with
the neopentyl group in an equatorial position, on the
basis of the structures of crystallographically character-
ized 4b and [ArClNNMe]Mo(CH2CMe3)Cl (ArCl ) 3,5-
C6Cl2H3).24
We propose that the alkylidyne ligand in 9 is formed
through an R,R-dehydrogenation reaction in which [F3-
NMe]Mo(CH2CMe3)2 is the intermediate, as shown in
eq 9.20 This proposal is supported by the amount of
The reaction between [Et3NH]{[F3NMe]MoCl3} and
3 equiv of Me3CCH2MgCl in THF led to diamagnetic
[F3NMe]Mo(CH2CMe3)(CCMe3) (9) in 68% yield (eq 8).
The 1H NMR spectrum of 9 showed two singlet reso-
nances corresponding to two distinct tert-butyl groups
at 1.37 and 0.66 ppm. A resonance at 1.56 ppm was
assigned to the CH2 protons of the neopentyl ligand. The
alkylidyne carbon resonance was located at 307.7 ppm
in the 13C NMR spectrum in C6D6, which is typical for
a d0 alkylidyne complex.31 For comparison, the alkyli-
dyne carbon resonance for [ArClNNMe]Mo(CCMe3)(CH2-
CMe3) was located at 309.8 ppm.24
dihydrogen produced in the reaction between [Et3NH]-
{[F3NMe]MoCl3} and 3 equiv of Me3CCH2MgCl, as
measured with a Toepler pump. A yield of 90% was
found for the collected H2 (mmol of H2/mmol [ of F3NMe]-
Mo(CH2CMe3)(CCMe3) produced), consistent with the
proposal shown in eq 9.
Amber crystals of 9 were grown from a mixture of
benzene and pentane at -30 °C. Crystallographic data,
The reaction between [Et3NH]{[F3NMe]MoCl3} and
3 equiv of Me3SiCH2MgCl in THF led to paramagnetic,
(31) Schrock, R. R. Chem. Rev. 2002, 102, 145.

672 Organometallics, Vol. 23, No. 4, 2004
Cochran et al.
SiMe3)2 versus that in 10 is consistent with what has
been found in W and Mo triamido/amine complexes.18-21
Syn th esis a n d Ch a r a cter iza tion of Mo Com -
p lexes Th a t Con ta in th e [(3-CF 3C6H4NCH2CH2)2-
NMe]2- Liga n d . One of the main limitations to the
chemistry of complexes that contain the [F5NMe]2-
ligand, we believe, is the presence of side reactions that
involve the ortho fluorides in the pentafluorophenyl
group. An example of such a complication, exchange of
two dimethylamido ligands on Mo with two ortho
fluorides on the [F5NMe]2- ligand, was presented in a
preliminary communication.22 Although complications
involving ortho fluorides of course are not possible in
complexes that contain the [F3NMe]2- ligand, synthesis
of large quantities of H2[F3NMe] by the current route
is limited. Therefore, we searched for a H2[(ArylNCH2-
CH2)2NMe] species that (i) could be prepared on a large
scale, (ii) would react with MoCl4 in the presence of
triethylamine to give [Et3NH]{[(ArylNCH2CH2)2NMe]-
MoCl3}, and (iii) would lack any substituent in the ortho
position. It would be most desirable if the aryl group
were relatively electron withdrawing (in order to in-
crease the acidity of the amine proton in an initial
adduct) and were to contain one or more fluorides (in
order to allow for 19F NMR to be a viable diagnostic tool
for following reactions that involve paramagnetic spe-
cies). These considerations, in addition to the low cost
of 3-CF3C6H4NH2, attracted us to the 3-CF3C6H4 group.
The triamine (3-CF3C6H4NHCH2CH2)2NMe (H2[CF3-
NMe]) can be synthesized conveniently in three steps,
the first being the known synthesis33 of MeN(CH2-
CO2H)2 on a mole scale in good yield. Phosphite-
mediated coupling34-36 of the diacid with 3-aminoben-
zotrifluoride, as shown in eq 11, and the borane-
dimethyl sulfide reduction of the amide,37 as shown in
eq 12, proceed smoothly in good yield. A relatively large
F igu r e 7. Thermal ellipsoid plot (30% probability level)
of the structure of [F3NMe]Mo(CH2CMe3)(CCMe3) (9).
Hydrogens have been omitted for clarity.
purple [F3NMe]Mo(CH2SiMe3)2 (10) in 72% yield (eq
10). The 19F NMR spectrum of 10 displayed two reso-
nances in a 2:1 ratio at -99.06 and -160.17 ppm,
corresponding to the freely rotating C6H2F3 rings on the
[F3NMe]2- ligand, while the 1H NMR spectrum of 10
showed two broad resonances at 3.6 and 1.2 ppm,
assigned to the two different Me3Si groups. Unfortu-
nately, no suitable crystals for X-ray diffraction could
be obtained. In one instance a single crystal suitable
for data collection was obtained, but the structure was
revealed to be a bridging dinitrogen complex of molyb-
denum, {[F3NMe]Mo(CH2SiMe3)}2(µ-N2), in which the
dinitrogen is located in the axial position.32 Since we
could not find a method that yielded {[F3NMe]Mo(CH2-
SiMe3)}2(µ-N2) reproducibly in reasonable quantities, we
mention it here only for informational purposes. The low
solubility of the dimeric dinitrogen complex is the
primary reason it was discovered and isolated.
The reaction between [Et3NH]{[F3NMe]WCl3} and 3
equiv of either Me3CCH2MgCl or Me3SiCH2MgCl yielded
five-coordinate diamagnetic, alkylidyne complexes of the
type [F3NMe]W(CH2R)(CR) (R ) CMe3 (11a ), SiMe3
(11b)). The alkylidyne carbon atom resonances were
located at 295.7 ppm in 11a and 336.8 ppm in 11b in
13C NMR spectra. We assume that [F3NMe]W(CH2-
CMe3)2 and [F3NMe]W(CH2SiMe3)2 are intermediates
in the reactions in which 11a and 11b are formed. The
more facile R,R-dehydrogenation in [F3NMe]W(CH2-
quantity of H2[CF3NMe] therefore can be obtained
relatively easily.
Addition of MoCl4(THF)2 to a THF solution of H2[CF3-
NMe] followed by 2 equiv of triethylamine led to a
(33) Berchet, G. J . Org. Synth. 1938, 18, 56.
(34) Barnes, D. J .; Chapman, R. L.; Vagg, R. S.; Watton, E. C. J .
Chem. Eng. Data 1978, 23, 349.
(32) Cochran, F. Ph.D. Thesis, Massachusetts Institute of Technol-
ogy, 2002.
(35) Liu, X.; Ilankumaran, P.; Guzei, I. A.; Verkade, J . G. J . Org.
Chem. 2000, 65, 701.

Mo and W Diamidoamine Complexes
Organometallics, Vol. 23, No. 4, 2004 673
yellow crystalline [CF3NMe]Mo(CCMe3)(CH2CMe3) (15)
in high yield. The alkylidyne carbon resonance was
found at 307.7 ppm in 15. Both compounds are analo-
gous to other compounds that have been discussed here.
Discu ssion
Little is known about the chemistry of Mo(IV) and
W(IV) diamidoamine complexes in general, and alkyl
complexes in particular. We are most interested in d2
alkyl complexes as a consequence of our discovery of the
R,R-dehydrogenation process in d2 alkyl complexes of
tungsten(IV) that contain the [(Me3SiNCH2CH2)3N]3-
ligand.18 R,R-Dehydrogenation is an intriguing way to
form d0 alkylidyne complexes from reduced alkyl com-
plexes, even (in [(Me3SiNCH2CH2)3N]W(CH2R) spe-
cies21) when the CH2R group contains â-protons. For
example, some R,R-dehydrogenation could conceivably
be taking place when neopentyllithium is added to WCl6
or MoCl5 in ether to give complexes of the type M(C-t-
Bu)(CH2-t-Bu)3 (in low yield), since the metal is reduced
before it is alkylated under the conditions employed in
the original experiments.38 R,R-Dehydrogenation is
presumed to involve formation first of an alkylidene
hydride complex by R-elimination followed by an R-ab-
straction of the remaining alkylidene R-hydrogen by the
hydride (e.g., as shown in eq 9). In [(Me3SiNCH2CH2)3N]-
MCH2R complexes it was shown that the R,R-dehydro-
genation reaction to give [(Me3SiNCH2CH2)3N]MtCR
complexes was most facile when R ) t-Bu and M ) W.
In fact, the only [(Me3SiNCH2CH2)3N]WCH2R complex
that could be isolated was [(Me3SiNCH2CH2)3N]WCH3,
since the methyl group is the least likely to undergo
R-elimination or R-abstraction reactions. The only [(Me3-
SiNCH2CH2)3N]MoCH2R complex that could be induced
to lose dihydrogen relatively cleanly was [(Me3SiNCH2-
CH2)3N]MoCH2-t-Bu, since the neopentyl group is the
most likely to undergo R-elimination or R-abstraction
reactions.39 Similar reactions of molybdenum and tung-
sten alkyl complexes that contain the [(C6F5NCH2-
CH2)3N]3- ligand are known,19 but in general the
synthesis of d2 alkyl complexes and R,R-dehydrogenation
in [(C6F5NCH2CH2)3N]3- species has been more limited
in scope, perhaps as a consequence of side reactions that
involve the ortho fluorides. Formation of [(arylNCH2-
CH2)3N]MCH2R complexes, where the aryl group is (for
example) an ordinary phenyl group,26,40,41 has not yet
been investigated.
F igu r e 8. Thermal ellipsoid plot (35% probability level)
of the anion structure of [Bu4N]{[CF3NMe]MoCl3} (12b).
Hydrogens have been omitted for clarity.
precipitate of Et3NHCl and a purple solution that
contains [Et3NH]{[CF3NMe]MoCl3} (12a ). [Bu4N]{[CF3-
NMe]MoCl3} (12b) can be prepared using conditions
analogous to those employed to prepare 1b and 6b.
Compound 12b also can be prepared by treating the
solution of crude 12a with excess tetrabutylammonium
chloride. Both 12a and 12b are dark purple, paramag-
netic solids analogous to compounds that have been
discussed previously in this paper. Relatively sharp CF3
resonances are observed in 19F spectra at -54.5 and
-54.8 ppm for 12a and 12b, respectively.
Complex 12b crystallized from a THF/pentane solu-
tion -30 °C in the triclinic space group P1h as dark
purple plates. Crystallographic data, collection param-
eters, and refinement parameters can be found in Table
1, selected bond lengths (Å) and angles (deg) are listed
in Table 2, and a thermal ellipsoid plot of the anion is
shown in Figure 8. The structure of the {[CF3NMe]-
MoCl3}- ion is analogous to the previously characterized
triethylammonium salts 1a and 2a ; however, the weakly
coordinating tetrabutylammonium cation shows no as-
sociation with the anion in the solid state. A comparison
of bond angles and distances of the cores of 1a , 2a , and
12b reveal minimal reorganization of the anion core
upon changing the metal from Mo to W or the cation
from Et3NH+ to Bu4N+. The M-Namide distances are
virtually the same in the three structures.
The paramagnetic dialkyl complex [CF3NMe]Mo(CH2-
SiMe3)2 (13) can be prepared in 60% yield through
addition of 3.1 equiv of ((trimethylsilyl)methyl)magne-
sium chloride to 12a in THF at -78 °C. The 19F
resonance is observed at -55.8 ppm. Compound 13 is
dark red and paramagnetic, with properties that are
very similar to those of 10. We have been unable to
obtain diffraction-quality crystals of 13. It seems likely
that it is a pseudo trigonal bipyramid analogous to 3.
As was found in the case of the [F3NMe] ligand, all
attempts to synthesize a stable dimethyl species were
unsuccessful.
Addition of 2 equiv of Me3CCH2MgCl in ether to [Et3-
NH]{[CF3NMe]MoCl3} in THF led to formation of dark
green, paramagnetic [CF3NMe]Mo(CH2CMe3)Cl (14),
while addition of 3 equiv of Me3CCH2MgCl in ether to
[Et3NH]{[CF3NMe]MoCl3} in THF led to formation of
The study of Mo and W d2 alkyl complexes that
contain a [(arylNCH2CH2)2NMe]2- ligand are compli-
cated if the amine donor remains bound to the metal,
since an alkyl can reside in either an “axial” or an
“equatorial” site, and since the rate of R-elimination or
-abstraction could differ dramatically for an alkyl in
each of these sites. On the basis of what we have seen
so far in this study, it appears that an alkyl group
prefers to occupy the equatorial site in an alkyl chloride
complex, and R,R-dehydrogenation from the equatorial
site is not facile, even for a neopentyl group bound to
(38) Clark, D. N.; Schrock, R. R. J . Am. Chem. Soc. 1978, 100, 6774.
(39) Schrock, R. R. In Reactions of Coordinated Ligands; Braterman,
P. R., Ed.; Plenum: New York, 1986.
(40) Greco, G. E.; Popa, A. I.; Schrock, R. R. Organometallics 1998,
17, 5591.
(41) Greco, G. E. Ph.D. Thesis, Massachusetts Institute of Technol-
ogy, 2000.
(36) Ray, M.; Golombek, A.; Hendrich, M. P.; Young, V. G., J r.;
Borovik, A. S. J . Am. Chem. Soc. 2000, 118, 6084.
(37) Lane, C. F. Chem. Rev. 1976, 76, 773.

674 Organometallics, Vol. 23, No. 4, 2004
Cochran et al.
W. Therefore, we suspect that it is the axial alkyl group
trans to the amine donor in a dialkyl complex that is
prone to R-elimination followed by R-abstraction to give
a species that contains the alkylidyne in the axial
position (e.g. as shown in eq 9). This is, of course, the
same type of site where R,R-dehydrogenation takes place
in triamidoamine complexes. Perhaps the most surpris-
ing feature of R,R-dehydrogenation reactions in diami-
doamine dialkyl complexes is that reductive elimination
of alkane does not compete with formation of the alkyl/
alkylidyne product.
and for neopentyl complexes versus (trimethylsilyl)-
methyl complexes.
In a preliminary communication we reported that
heating a benzene solution of [F3NMe]Mo(CH2SiMe3)2
at 62 °C for 24 h led to formation of {[F3NMe]Mo-
(CSiMe3)}2 in 37% yield, a species that contains bridging
alkylidyne ligands and a Mo-Mo bond. Therefore,
bimolecular alternatives to intramolecular R,R-dehy-
drogenation in some [(arylNCH2CH2)2NMe]Mo(CH2R)2
species are competitive. Now that [CF3NMe]2- com-
plexes are available in quantity, in particular, [CF3NMe]-
Mo(CH2SiMe3)2, we hope to address some of the issues
surrounding the mode of decomposition of d2 dialkyl
complexes more broadly. We are especially interested
in how external reagents direct decomposition pathways
of dialkyl complexes. We also wish to prepare more
examples of [CF3NMe]Mo(CH2R)X species, for example,
where X is an alkoxide, amide, or thiolate, to broaden
our knowledge of ground-state structures and modes of
decomposition of monoalkyl d2 complexes. These studies
are under way and will be reported in full in due course.
At this stage we believe that the two unpaired
electrons in a dialkyl complex reside in the dxz and
dyz orbitals (if the z axis contains the Namine-M
bond). However, we suspect that the first (reversible20)
R-elimination step may take place from the singlet state,
in which one of these orbitals is doubly occupied and
the other is empty. The possibility that a singlet state
is required adds to the complexity that surrounds
reactions of this general type. The relationship between
spin states and reaction rates in transition-metal chem-
istry has been a subject of controversy,21,42,43 although
evidence that reaction rates can depend on spin state,
at least when a second- or third-row metal is involved,
has been accumulating.44-48 Finally, it should be noted
that in very crowded complexes, e.g., dineopentyl spe-
cies, the amine donor may essentially dissociate from
the metal, thereby creating a pseudo tetrahedral species
with approximately Cs symmetry, in which a singlet
state may be more accessible. In short, it is premature
to attempt to explain in detail how R,R-dehydrogenation
takes place in complexes of the type discussed here.
Exp er im en ta l Section
Gen er a l Deta ils. All experiments were conducted under
dinitrogen in
a Vacuum Atmospheres glovebox or using
standard Schlenk techniques. Pentane was washed with
HNO3/H2SO4 (5/95 v/v), sodium bicarbonate, and water, stored
over CaCl2, sparged with nitrogen, and then passed through
a column of activated alumina. Diethyl ether and toluene were
sparged with N2 and passed through a column of activated
alumina. THF was distilled from purple sodium benzophenone
ketyl or sparged with nitrogen and passed through two
columns of activated alumina. Acetonitrile was distilled from
CaH2. Deuterated solvents were sparged with N2 for several
minutes and dried over activated 4 Å molecular sieves unless
otherwise noted. All solvents, with the exception of acetonitrile,
were stored in the drybox over activated 4 Å molecular sieves.
Pyridine and triethylamine were distilled from CaH2 and
stored over 4 Å molecular sieves. Molecular sieves and Celite
were activated and dried in vacuo (>10-3 Torr) for 24 h at ∼180
°C.
In the chemistry presented here it seems that the
[F5NMe]2- ligand sterically protects the metal to a
greater degree than either the [F3NMe]2- or [CF3NMe]2-
ligands, as one might expect. For example, although [F5-
NMe]MoMe2 (3) could be prepared, no [F3NMe]2- or
[CF3NMe]2- analogues could be prepared; we suspect
that they decompose too readily bimolecularly. Only [F5-
NMe]Mo(CH2CMe3)Cl (4b) could be prepared, while all
attempts to add two neopentyl groups (which would
almost certainly would yield [F5NMe]Mo(CCMe3)(CH2-
CMe3)) failed, perhaps in part because of side reactions
involving aryl fluorides. In contrast, [F3NMe]2- and
[CF3NMe]2- bis((trimethylsilyl)methyl) and neopentyl
neopentylidyne complexes (which arise via dineopentyl
compounds) could be prepared readily. The chemistry
of [(C6F5NCH2CH2)3N]3- complexes of Mo and W19 also
was found to be more limited than that of [(Me3-
SiNCH2CH2)3N]3- complexes of Mo and W,20,21 perhaps
again because of steric problems and side reactions that
involve attack in the pentafluorophenyl rings, as noted
above. Formation of alkylidynes by R,R-dehydrogenation
again appears to be more facile for tungsten than for
molybdenum diamidoamine complexes reported here
1
Reported H and 13C NMR chemical shifts are listed as parts
per million downfield from tetramethylsilane and were refer-
enced using the residual protio solvent resonance. Unless
otherwise noted, 13C NMR experiments were proton decoupled.
19F NMR data were referenced using C6F6 in CDCl3 as an
external standard (-163 ppm vs CFCl3). Coupling constants
are listed in hertz, and routine coupling constants are not
reported. Spectra were obtained at ∼22 °C unless noted
otherwise. Elemental analyses were performed by H. Kolbe
Microanalytical Laboratory, Mu¨lheim an der Ruhr, Germany.
All Grignard reagents were titrated before use.
MoCl4(THF)2,49,50 WCl4(dme),29 and MeN(CH2CO2H)233 were
prepared according to literature procedures. Grignard reagents
were prepared by standard techniques. All other chemicals
were purchased from commercial suppliers and used as
received.
(C6F 5NHCH2CH2)2NMe (H2[F 5NMe]). Methyl iodide (1.86
mL, 29.88 mmol) was added dropwise to a stirred mixture of
(C6F5NHCH2CH2)2NH (10 g, 22.97 mmol) and K2CO3 (17.5 g,
126.62 mmol) in CH3CN (120 mL). The mixture was stirred
for 15 h, and the volatile components were removed in vacuo.
(42) Schrock, R. R.; Shih, K.-Y.; Dobbs, D.; Davis, W. M. J . Am.
Chem. Soc. 1995, 117, 6609.
(43) Detrich, J . L.; Reinaud, O. M.; Rheingold, A. L.; Theopold, K.
H. J . Am. Chem. Soc. 1995, 117, 11745.
(44) J in, N.; Groves, J . T. J . Am. Chem. Soc. 1999, 121, 2923.
(45) Veige, A. S.; Slaughter, L. M.; Wolczanski, P. T.; Matsunaga,
N.; Decker, S. A.; Cundari, T. R. J . Am. Chem. Soc. 2001, 123, 6419.
(46) Keogh, D. W.; Poli, R. J . Am. Chem. Soc. 1997, 119, 2516.
(47) J ensen, V. R.; Poli, R. J . Phys. Chem. A 2003, 107, 1424.
(48) Harvey, J . N.; Poli, R.; Smith, K. M. Coord. Chem. Rev. 2003,
238-239, 347.
(49) Dilworth, J . R.; Richards, R. L.; Chen, G. J .; McDonald, J . W.
Inorg. Synth. 1980, 20, 119.
(50) Stoffelbach, F.; Saurenz, D.; Poli, R. Eur. J . Inorg. Chem. 2001,
2699.
(51) (a) van der Sluis, P.; Spek, A. L. Acta Crystallogr. 1990, A46,
194-201. (b) Spek, A. L. Acta Crystallogr. 1990, A46, C34.

Mo and W Diamidoamine Complexes
Organometallics, Vol. 23, No. 4, 2004 675
The residue was then washed with water (200 mL) and
extracted into ethyl acetate (200 mL). The organic layer was
separated, dried over MgSO4, and concentrated to dryness. The
resulting solid was then extracted with CHCl3 (100 mL), and
the mixture was filtered in order to remove any insoluble white
powder. Removal of the CHCl3 in vacuo left a waxy, yellow
solid: yield 6.5 g (63%); 1H NMR (CDCl3) δ 4.20 (br s, 2, NH),
3.41 (q, 4, CH2), 2.65 (t, 4, CH2), 2.29 (s, 3, NCH3); 13C NMR
(CDCl3) δ 139.78, 136.55, 135.10, 131.87, 124.25 (C6F5), 57.05
(NCH3), 43.46 (CH2), 41.14 (CH2); 19F NMR (CDCl3) δ -160.48
(d, 4, Fo), -164.93 (t, 4, Fm), -172.26 (t, 2, Fp); HRMS (EI)
calcd for C17H13N3F10 449.094 98, found 449.0940.
13C NMR (125 MHz, CDCl3) δ 40.99 (CH2), 41.91 (CH2), 55.95
(NCH3), 108.85, 113.77, 116.074, 124.61 (q, J CF ) 272.38 Hz,
CF3C6H4), 129.81, 131.62 (q, J CF ) 31.6 Hz, C6H4), 148.61; 19
F
NMR (283 MHz, CDCl3) δ -63.2 (s); HRMS (ESI) calcd for
C
19H21F6N3 406.1712 [M + H+], found 406.1715 [M + H+].
[Et3NH]{[F 5NMe]MoCl3} (1a ). MoCl4(THF)2 (2.547 g, 6.67
mmol) was added as a solid to a stirred solution of (C6F5-
NHCH2CH2)2NMe (3 g, 6.67 mmol) in THF (50 mL) at room
temperature. The reaction mixture became nearly homoge-
neous after approximately 30 min. Addition of NEt3 (2.0 mL,
14.35 mmol) caused a white precipitate to form and the
resulting mixture was stirred for an additional 2 h. The white
powder was removed by filtering the reaction mixture through
Celite. The product precipitated upon dropwise addition of the
THF solution to a volume (100 mL) of rapidly stirred pentane.
The burgundy powder was collected on a frit, washed liberally
with pentane, and dried in vacuo: yield 4.70 g (83%); 1H NMR
(tol-d8) δ 1.51, 1.19 (Et3NH); 19F NMR (THF) δ -95.46,
(C6H2F 3NHCH2CH2)2NMe (H2[F 3NMe]). A solution of
H2[F5NMe] (3.37 g, 7.49 mmol) in THF (20 mL) was added
via syringe to LiAlH4 (1.28 g, 33.74 mmol) in THF (30 mL) at
room temperature. The reaction mixture was heated to reflux
for 4 h, cooled to room temperature, and stirred for an
additional 15 h. Water was then added dropwise until gas
evolution ceased. The reaction mixture was filtered through
Celite, and the precipitate was washed liberally with ad-
ditional THF. Volatile components were removed from the
filtrate under vacuum. The residue was extracted twice with
200 mL of dichloromethane, and the solution was washed with
0.5 M NaOH (300 mL). The organic layers were combined and
dried over MgSO4. All volatile components were removed in
vacuo to afford a thick yellow oil: yield 4.74 g (85%); 1H NMR
(C6D6) δ 5.73 (m, 4, C6H2F3), 3.46 (br s, 2, NH), 2.37 (q, 4, CH2),
1.94 (t, 4, CH2), 1.76 (s, 3, NCH3); 13C NMR (C6D6) δ 153.77,
151.80, 144.96, 133.83, 131.93, 96.64, 96.45 (C6H2F3), 55.77
(NCH3), 41.78 (CH2), 41.35 (CH2); 19F NMR (C6D6) δ -136.00
(m, 4, Fm), -177.29 (m, 2, Fp); HRMS (EI) calcd for C17H17N3F6
377.132 667, found 377.1319. Anal. Calcd for C17H17N3F6: C,
54.11; H, 4.54; N, 11.14. Found: C, 54.01; H, 4.43; N, 11.22.
CH3N[CH2CONH(3-CF 3C6H4)]2. In a 2 L round-bottom
flask equipped with an addition funnel, stir bar, and reflux
condenser was added 74 g (0.5 mol) of methyliminodiacetic
acid.33 A 300 mL portion of anhydrous pyridine was added via
cannula. To the resulting suspension was added 162.7 g (1 mol)
of 3-aminobenzotrifluoride (which had been sparged with
dinitrogen for 10 min) via cannula. The suspension was heated
to ca. 50 °C, and 260 mL (1.06 mol) of triphenyl phosphite was
added dropwise. The mixture was heated to 100 °C for 20 h.
The homogeneous, bright yellow reaction mixture was cooled
to room temperature, and pyridine was removed at reduced
pressure. The resulting thick yellow oil was stirred with 500
mL of 5 N HCl in methanol for 1 h, and then the entire mixture
was carefully added to 2 L of 2 N sodium hydroxide and
extracted with 3 × 1 L of CH2Cl2. The extracts were combined
and dried over MgSO4, and the solvent was removed at reduced
pressure. Crude CH3N[CH2CONH(3-CF3C6H4)]2 was obtained
as an off-white solid. The product was recrystallized by adding
an equal volume of hexanes to a concentrated THF solution
and storing at ∼5 °C overnight to give a white solid that was
dried in vacuo: yield 159.3 g (74%); 1H NMR (300 MHz, CDCl3)
δ 2.55 (s 3H, CH3N), 3.40 (s, 4H, NCH2CONH), 7.35-7.44 (m,
4H, Ar H), 7.85 (d, 2H, Ar H), 9.22 (s, 2H, CH2CONHAr); 19F
NMR (283 MHz, CDCl3) δ -63.87 (s); HRMS (ESI) calcd for
-119.25, -131.27, -134.95, -169.26. Anal. Calcd for C23H27
-
N4F10Cl3Mo: C, 36.75; H, 3.62; N, 7.45; Cl, 14.15. Found: C,
36.64; H, 3.54; N 7.33; Cl, 14.02.
[Bu 4N]{[F 5NMe]MoCl3} (1b). Tetrabutylammonium chlo-
ride (0.203 g, 0.73 mmol) was added to a solution of [Et3NH]-
[(C6F5NCH2CH2)2NMe]MoCl3 (0.5 g, 0.67 mmol) in THF (10
mL). The mixture was stirred vigorously for 12 h and filtered
through Celite. The volatile components were removed in
vacuo. The residue was dissolved in toluene (20 mL), the
extract was filtered, and the volume of the extract was halved
by removing solvent in vacuo. Dropwise addition of the toluene
solution to a rapidly stirred volume of pentane (125 mL)
produced a bright red powder, which was collected on a frit,
washed liberally with pentane, and dried in vacuo: yield 0.513
g (98%); 1H NMR (C6D6) δ 18.82, 4.15, 1.84, 1.21, 0.97 (Bu4N),
-29.98, -123.84, -149.7; 19F NMR (C6D6) δ -92.55, -115.76,
-129.40, -133.74, -168.07; µeff ) 3.1 µB (Evans method). Anal.
Calcd for C33H47N4F10Cl3Mo: C, 44.43; H, 5.31; N, 6.28; Cl,
11.92. Found: C, 44.28; H, 5.39; N, 6.16; Cl, 12.01.
[Et3NH]{[F 5NMe]WCl3} (2a ). A solution of (C6F5NHCH2-
CH2)2NMe (1.0 g, 2.22 mmol) and NEt3 (0.67 mL, 4.81 mmol)
in diethyl ether (10 mL) was added to a stirred mixture of
WCl4(dme) (0.92 g, 2.21 mmol) and diethyl ether (10 mL) at
-30 °C. The reaction mixture was warmed to room tempera-
ture and stirred for 15 h. The yellow-green precipitate was
collected on a frit, washed with additional diethyl ether (10
mL), and extracted with THF (15 mL). The mixture was
filtered through Celite in order to remove an off-white powder.
The volatile components were removed from the extract in
vacuo, and the residue was washed with diethyl ether (10 mL)
and collected on a frit. The resulting material was dissolved
in THF (15 mL), and the solution was filtered through Celite
and added dropwise to rapidly stirred pentane (125 mL). The
olive green powder produced was collected on a frit, washed
liberally with pentane, and dried in vacuo: yield 1.10 g (60%);
1H NMR (tol-d8) δ 5.54 (NMe), 0.42, -0.44 (Et3NH), -11.51,
-32.43, -48.30, -75.89 (CH2); 19F NMR (THF) δ -90.96,
105.14, -133.65, -134.48, -160.62. Anal. Calcd for C23H27N4F10
-
Cl3W: C, 32.90; H, 3.24; N, 6.67; Cl, 12.67. Found: C, 33.11;
H, 3.21; N, 6.64; Cl, 12.58.
C
19H17F6N3 434.1298 [M + H+], found 434.1304 [M + H+].
CH3N[CH2CH2NH(3-CF 3C6H4)]2 (H2[CF 3NMe]). To 52.18
[Bu 4N]{[F 5NMe]WCl3} (2b). Tetrabutylammonium chlo-
ride (0.182 g, 0.65 mmol) was added to a solution of [Et3NH]-
{[(C6F5NCH2CH2)2NMe]WCl3} (0.45 g, 0.54 mmol) in THF (10
mL). The mixture was stirred vigorously for 12 h and filtered
through Celite. The volatile components were removed from
the filtrate in vacuo, and the residue was dissolved in toluene
(20 mL). The mixture was filtered, and the volume was reduced
by half in vacuo. The toluene solution was added to rapidly
stirred pentane (125 mL) to yield a light green powder, which
was collected on a frit, washed liberally with pentane, and
dried in vacuo: yield 0.476 g (91%); 1H NMR (C6D6) δ 2.66
(NMe), 0.69, 0.16, -0.42 (Bu4N), -11.04, -32.48, -45.80,
-72.53 (CH2); 19F NMR (C6D6) δ -88.34, -102.82, -130.99,
g of CH3N[CH2CONH(3-CF3C6H4)]2 (0.12 mol) in 230 mL of
THF was added 62 mL (0.62 mol) of BH3SMe2 dropwise. The
mixture was then refluxed for 6 h and cooledl to room
temperature. The reaction mixture was carefully quenched
with 250 mL of 5 N HCl, made alkaline with NaOH pellets,
and extracted (3 × 250 mL) with methylene chloride. The
extracts were combined and dried with MgSO4. The mixture
was filtered, and the solvent was removed at reduced pressure
1
to yield H2[CF3NMe] as a colorless oil: yield 33 g (68%); H
NMR (300 MHz, C6D6) δ 1.77 (s, 3H, CH3N), 1.99 (t, 4H, NCH2-
CH2N), 2.53 (q, NCH2CH2N), 3.73 (br s, 2H, NH), 6.3 (m, 2H,
Ar H), 6.66 (s, Ar H), 6.90 (d, 2H, Ar H), 7.13 (s, 2H, Ar H);

676 Organometallics, Vol. 23, No. 4, 2004
Cochran et al.
-132.28, -158.76; µeff ) 2.7 µB (Evans method). Anal. Calcd
for C33H47N4F10Cl3W: C, 40.45; H, 4.83; N, 5.72; Cl, 10.85.
Found: C, 40.34; H, 4.97; N, 5.64; Cl, 10.93.
[Et3NH]{[F 3NMe]MoCl3} (6a ). MoCl4(THF)2 (2.02 g, 5.30
mmol) was added as a solid to a stirred solution of H2[F3NMe]
(2 g, 5.30 mmol) in THF (40 mL) at room temperature. The
reaction mixture became nearly homogeneous and deep red
after approximately 10 min. Addition of NEt3 (1.63 mL, 11.69
mmol) caused a white precipitate to form. The resulting purple
reaction mixture was stirred for 1 h, and the white powder
was removed by filtering the reaction mixture through Celite.
The product precipitated upon dropwise addition of the THF
solution to rapidly stirred, cold pentane (150 mL). The dark
purple powder was collected on a frit, washed liberally with
pentane, and dried in vacuo: yield 3.15 g (87%); 1H NMR
(C6D6) δ 1.38, 1.12 (Et3NH); 19F NMR (C6D6) δ -104.85,
-206.57. Anal. Calcd for C23H31N4Cl3F6Mo: C, 40.64; H, 4.60;
N, 8.24; Cl, 15.65. Found: C, 40.72; H, 4.55; N, 8.21; Cl, 15.57.
[Bu 4N]{[F 3NMe]MoCl3} (6b). Tetrabutylammonium chlo-
ride (0.25 g, 0.90 mmol) was added to a solution of [Et3NH]-
{[F3NMe]MoCl3} (0.5 g, 0.74 mmol) in THF (10 mL). The
mixture was stirred vigorously for 20 h and filtered through
Celite. The volatile components were removed in vacuo. The
residue was dissolved in toluene (20 mL), and the toluene
solution was filtered and added dropwise to a rapidly stirred
volume of cold pentane (100 mL). The purple powder was
collected on a frit, washed liberally with pentane, and dried
in vacuo: yield 0.54 g (90%); 1H NMR (C6D6) δ 28.26, 6.11,
1.64, 1.21, 0.97 (Bu4N), -3.84, -29.67, -96.83, -99.60; 19F
NMR (C6D6) δ -103.89 (4, Fm), -207.48 (2, Fp); µeff ) 3.1 µB
(Evans method). Anal. Calcd for C33H51N4Cl3F6Mo: C, 48.33;
H, 6.27; N, 6.83; Cl, 12.97. Found: C, 48.35; H, 6.35; N, 6.69;
Cl, 12.85.
[Et3NH]{[F 3NMe]WCl3} (7a ). WCl4(dme) (1.0 g, 2.1 mmol)
was added to a solution of H2[F3NMe] (0.79 g, 2.1 mmol) and
NEt3 (0.64 mL, 4.6 mmol) in diethyl ether (30 mL) at room
temperature. The reaction mixture was stirred for 15 h. The
mixture was taken to dryness in vacuo, and the residue was
extracted with THF (15 mL). The resulting solution was
filtered through Celite, and the filtrate was added dropwise
to rapidly stirred, cold pentane (75 mL). The dark orange
powder produced was collected on a frit, washed liberally with
pentane, and dried in vacuo: yield 1.39 g (86%); 1H NMR
(C6D6) δ 28.70, 0.04, 0.15 (Et3NH), -1.33 (Et3NH), -4.27
(Et3NH), -15.26, -32.03, -38.77, -45.91; 19F NMR (C6D6) δ
-108.34, -177.86. Anal. Calcd for C23H31N4Cl3F6W: C, 35.98;
H, 4.07; N, 7.30; Cl, 13.85. Found: C, 36.08; H, 3.92; N, 7.21;
Cl, 13.76.
[Bu 4N]{[F 3NMe]WCl3} (7b). Tetrabutylammonium chlo-
ride (0.12 g, 0.42 mmol) was added to a solution of [Et3NH]-
{[F3NMe]WCl3} (0.30 g, 0.38 mmol) in THF (5 mL). The
mixture was stirred vigorously for 14 h and filtered through
Celite. The volatile components were removed from the filtrate
in vacuo, and the residue was dissolved in toluene (15 mL).
The mixture was filtered, and the toluene solution was added
to rapidly stirred, cold pentane (75 mL) to yield a bright orange
powder, which was collected on a frit, washed liberally with
pentane, and dried in vacuo: yield 0.27 g (78%); 1H NMR
(C6D6) δ 28.74, 0.65 (Bu4N), 0.44 (Bu4N), -0.44 (Bu4N), -0.61
(Bu4N), -2.55, -13.88, -27.46, -39.21, -39.86; 19F NMR
(C6D6) δ -107.83 (m, 4, Fm), -179.38 (m, 2, Fp). µeff ) 2.7 µB
(Evans method). Anal. Calcd for C33H51N4Cl3F6W: C, 43.65;
H, 5.66; N, 6.17; Cl, 11.71. Found: C, 43.78; H, 5.72; N, 6.06;
Cl, 11.63.
[F 3NMe]Mo(CH2CMe3)Cl (8). A solution of Me3CCH2MgCl
(0.4 mL, 1.75 M in Et2O) was added to a solution of [Et3NH]-
{[F3NMe]MoCl3} (0.2 g, 0.29 mmol) in THF (7.5 mL) at -30
°C. The reaction mixture was warmed to room temperature
while it was stirred for 1 h. The reaction mixture was then
added to cold, stirred pentane (100 mL), and the precipitate
produced was collected on a frit, washed liberally with ad-
ditional pentane, and dried in vacuo. The gray-brown solid was
then added to Et2O (10 mL), and 1,4-dioxane (0.055 mL) was
added followed by stirring for 5 min. The solid was collected
[F 5NMe]MoMe2 (3). A solution of MeMgCl (0.94 mL, 3.2
M in THF) was added to a solution of [Et3NH]{[(C6F5NCH2-
CH2)2NMe]MoCl3} (0.75 g, 1.01 mmol) in THF (20 mL) at -30
°C. The reaction mixture immediately turned dark green and
was warmed to room temperature while it was stirred. After
30 min, the solution was concentrated to dryness in vacuo.
The residue was extracted into ether (20 mL), and 1,4-dioxane
(0.28 mL) was added. The mixture was stirred for 10 min and
filtered through Celite. The filtrate was added dropwise to a
rapidly stirred volume of pentane (100 mL). A small amount
of brown solid was filtered off. The filtrate was concentrated
to approximately 15 mL to produce green crystalline material,
which was collected, washed with pentane, and dried in
vacuo: yield 0.29 g (50%). An analytically pure sample was
obtained by recrystallization of the crude product from a
diethyl ether solution layered with pentane at -30 °C: 1H
NMR (C6D6) δ 26.79 (NMe), 10.82, 5.15, -51.59, -81.94 (CH2);
19F NMR (THF) δ -57.25, -72.97, -105.98, -147.40, -148.99;
µeff ) 3.1 µB (Evans method). Anal. Calcd for C19H17N3F10Mo:
C, 39.81; H, 2.99; N, 7.33. Found: C, 39.66; H, 3.09; N, 7.38.
[F 5NMe]MoMeCl (4a ). 2,6-Lutidinium chloride (86 mg,
0.60 mmol) was added to a solution of [(C6F5NCH2CH2)2NMe]-
MoMe2 (0.312 g, 0.54 mmol) in diethyl ether (18 mL) at -30
°C. The reaction mixture was stirred for 2 h. Tan solids were
filtered off, and the volatile components were removed in
vacuo. The residue was dissolved in minimal diethyl ether,
and the solution was layered with pentane and chilled to -30
°C overnight. The resulting blue-green crystals were collected
and dried in vacuo: yield 0.151 g (47%). An analytically pure
sample was recrystallized from a solution of diethyl ether
layered with pentane at -30 °C: 1H NMR (tol-d8) δ 14.26,
-54.59, -84.36; 19F NMR (Et2O) δ -86.61, -104.10, -105.13,
-141.87, -159.39. Anal. Calcd for C18H14N3F10ClMo: C, 36.41;
H, 2.38; N, 7.08; Cl, 5.97. Found: C, 36.52; H, 2.32; N, 7.04;
Cl, 5.91.
[F 5NMe]Mo(CH2CMe3)Cl (4b). A solution of Me3CCH2-
MgCl (0.28 mL, 2.07 M in THF) was added to a solution of
[Et3NH]{[(C6F5NCH2CH2)2NMe]MoCl3} (0.2 g, 0.11 mmol) in
THF (20 mL) at -30 °C. The reaction mixture immediately
turned dark green and was warmed to room temperature while
it was stirred. After 30 min, the solution was concentrated to
dryness in vacuo and the residue extracted into 30 mL of
toluene. 1,4-Dioxane (0.05 mL) was added, followed by stirring
for an additional 20 min. The mixture was filtered through
Celite and the filtrate added dropwise to cold, stirred pentane
(100 mL). The bright green, crystalline precipitate was col-
lected on a frit, washed liberally with pentane, and dried in
vacuo: yield 92 mg (60%); 1H NMR (CD2Cl2) δ 9.5, 6.3, 3.2
(CMe3), -59.6-82.8; 19F NMR (CD2Cl2) δ -88.67, -98.05,
-104.90, -138.46, -160.10. Anal. Calcd for C22H22N3F10
-
ClMo: C, 40.66; H, 3.41; N, 6.47; Cl, 5.46. Found: C, 40.63;
H, 3.54; N, 6.40; Cl, 5.56.
[F 5NMe]W(CH2CMe3)Cl (5). A solution of Me3CCH2MgCl
(0.29 mL, 2.07 M in THF) was added to a solution of [Et3NH]-
{[(C6F5NCH2CH2)2NMe]WCl3} (0.2 g, 0.24 mmol) in THF (20
mL) at -30 °C. The reaction mixture immediately turned dark
green and was warmed to room temperature while it was
stirred. After 30 min, the solution was concentrated to dryness
in vacuo and the residue extracted into 30 mL of toluene. 1,4-
Dioxane (0.05 mL) was added, followed by stirring for an
additional 20 min. The mixture was filtered through Celite
and the filtrate added dropwise to cold, stirred pentane (75
mL). The green precipitate was collected on a frit, washed
liberally with pentane, and dried in vacuo: yield 80 mg (45%);
1H NMR (CD2Cl2) δ 10.51 (CMe3), -5.07, -8.95, -34.45,
-58.23; 19F NMR (CD2Cl2) δ -88.67, -98.05, -104.90, -138.46,
-160.10. Anal. Calcd for C22H22N3F10ClW: C, 35.82; H, 3.01;
N, 5.70; Cl, 4.81. Found: C, 36.04; H, 3.11; N, 5.59; Cl, 4.72.

Mo and W Diamidoamine Complexes
Organometallics, Vol. 23, No. 4, 2004 677
on a frit and washed with additional Et2O. The solid was
transferred to a 20 mL vial, extracted three times with CH2-
Cl2 (20 mL), and filtered. The combined filtrates were concen-
trated in vacuo until a green precipitate began to form. The
solution was then added dropwise to rapidly stirred pentane
(100 mL), and the green powder produced was collected on a
frit, washed liberally with additional pentane, and dried in
vacuo: yield 73 mg (43%); 19F NMR (THF) δ -107.20 (4, Fm),
-164.96 (2, Fp). Anal. Calcd for C22H26N3F6ClMo: C, 45.73;
H, 4.54; N, 7.27; Cl, 6.14. Found: C, 45.66; H, 4.56; N, 7.17;
Cl, 6.19.
[F 3NMe]Mo(CH2CMe3)(CCMe3) (9). A solution of Me3-
CCH2MgCl (0.43 mL, 2.27 M in Et2O) was added to a solution
of [Et3NH]{[F3NMe]MoCl3} (0.2 g, 0.29 mmol) in THF (10 mL)
at -30 °C. After the reaction mixture was warmed to room
temperature and stirred for 1 h, all volatile components were
removed in vacuo. The residue was extracted into toluene (20
mL), and 1,4-dioxane (0.135 mL) was added. The mixture was
stirred for 10 min and filtered through Celite. The filtrate was
added dropwise to a rapidly stirred volume of cold pentane
(100 mL). A small amount of dark brown precipitate was
filtered off, and the filtrate was concentrated to dryness to
leave a brown crystalline solid: yield 0.122 g (68%). Analyti-
cally pure, amber crystals suitable for X-ray diffraction were
grown from a mixture of benzene and pentane at -30 °C: 1H
NMR (C6D6) δ 6.63 (m, 4, C6H2F3), 3.08 (t, 4, CH2), 2.13 (m, 2,
CH2), 1.94 (s, 3, NCH3), 1.91 (m, 2, CH2), 1.56 (s, 2, CH2), 1.37
(s, 9, C(CH3)3), 0.66 (s, 9, C(CH3)3); 13C NMR (C6D6) δ 307.74
(CCMe3), 160.28, 152.60, 149.31, 138.79, 135.55, 109.11 (C6H2F3),
72.74, 59.44, 55.59, 51.42, 44.49, 36.00, 35.90, 30.56; 19F NMR
(C6D6) δ -138.46 (m, 4, Fm), -170.87 (m, 2, Fp). Anal. Calcd
for C27H35N3F6Mo: C, 53.03; H, 5.77; N, 6.87. Found: C, 52.94;
H, 5.78; N, 6.83.
[F 3NMe]Mo(CH2SiMe3)2 (10). A solution of Me3SiCH2MgCl
(1.94 mL, 1.0 M in Et2O) was added to a solution of [Et3NH]-
{[F3NMe]MoCl3} (0.4 g, 0.59 mmol) in THF (20 mL) at -30
°C. After the reaction mixture was warmed to room temper-
ature and stirred for 1 h, all volatile components were removed
in vacuo. The residue was extracted into toluene (20 mL), and
1,4-dioxane (0.19 mL) was added. The mixture was stirred for
10 min and filtered through Celite. The filtrate was added
dropwise to a rapidly stirred volume of cold pentane (120 mL)
and filtered a second time to remove a small amount of gray
precipitate. All volatile components were removed in vacuo to
leave a purple, crystalline powder: yield 0.27 g (72%); 1H NMR
(C6D6) δ 21.29, 13.93, 3.58 (Si(CH3)3), 1.16 (Si(CH3)3), -40.28,
-62.26; 19F NMR (C6D6) δ -99.06 (m, 4, Fm), -160.17 (m, 2,
Fp); µeff ) 3.1 µB (Evans method). Anal. Calcd for C25H37N3F6-
Si2Mo: C, 46.50; H, 5.78; N, 6.51. Found: C, 46.38; H, 5.71;
N, 6.54.
[F 3NMe]W(CH2CMe3)(CCMe3) (11a ). A solution of Me3-
CCH2MgCl (0.33 mL, 1.3 M in Et2O) was added to a solution
of [Et3NH]{[F3NMe]WCl3} (0.1 g, 0.13 mmol) in THF (8 mL)
at -30 °C. After the reaction mixture was warmed to room
temperature and stirred for 4 h, all volatile components were
removed in vacuo. The residue was extracted into toluene (6
mL), and 1,4-dioxane (0.036 mL) was added. The mixture was
stirred for 10 min and filtered through Celite. The filtrate was
concentrated to dryness in vacuo to leave a tan powde: yield
75 mg (82%). An analytically pure sample was recrystallized
from a mixture of diethyl ether and pentane at -30 °C: 1H
NMR (CD2Cl2) δ 6.75 (m, 4, C6H2F3), 3.85 (m, 2, CH2), 3.79
(m, 2, CH2), 3.02 (m, 2, CH2), 2.78 (m, 2, CH2), 2.69 (s, 3,
NCH3), 1.22 (s, 9, C(CH3)3), 1.21 (s, 2, CH2), 0.44 (s, 9, C(CH3)3);
13C NMR (CD2Cl2) δ 295.71 (CCMe3), 160.74, 151.68, 149.23,
138.30, 135.87, 109.94 (C6H2F3), 76.55, 59.63, 54.54, 49.52,
44.72, 35.27, 34.73, 31.65; 19F NMR (CD2Cl2) δ -139.15 (m, 4,
Fm), -171.42 (m, 2, Fp). Anal. Calcd for C27H35N3F6W: C, 46.37;
H, 5.04; N, 6.01. Found: C, 46.43; H, 5.09; N, 5.95.
of [Et3NH]{[F3NMe]WCl3} (91 mg, 0.12 mmol) in THF (10 mL)
at -30 °C. After the reaction mixture was warmed to room
temperature and stirred for 1 h, all volatile components were
removed in vacuo. The light brown residue was extracted into
toluene (5 mL), and 0.07 mL of 1,4-dioxane was added. After
it was stirred for an additional 10 min, the solution was filtered
throuh Celite and the filtrate added dropwise to a stirred
volume of cold pentane (50 mL). The pentane was removed in
vacuo to leave a brown oil, which was redissolved in a minimal
amount of pentane and cooled to -30 °C to produce analytically
pure, amber crystals: yield 45 mg (52%); 1H NMR (C6D6) δ
6.80 (m, 4, C6H2F3), 3.08 (m, 4, CH2), 2.00 (m, 2, CH2), 1.88 (s,
3, NCH3), 1.76 (m, 2, CH2), 1.04 (s, 2, CH2), 0.24 (s, 9, Si(CH3)3),
0.36 (s, 9 Si(CH3)3); 13C NMR δ 336.84 (CCMe3), 161.36, 152.20,
148.89, 138.81, 135.50, 109.00 (C6H2F3), 58.13, 55.63, 47.40,
44.47, 4.44, 2.08; 19F NMR (C6D6) δ -137.50 (m, 4, Fm),
-170.19 (m, 2, Fp). Anal. Calcd for C25H35N3F6Si2W: C, 41.04;
H, 4.82; N, 5.74. Found: C, 40.93; H, 4.88; N, 5.84.
[Et3NH]{[CF 3NMe]MoCl3} (12a ). MoCl4(THF)2 (2.79 g,
0.78 mmol) was added in several portions to a stirred solution
of H2[CF3NMe] (3.14 g, 0.78 mmol) in 50 mL of THF. The
solution was stirred for 30 min at room temperature, upon
which the solution turned red. Et3N (2.28 mL, 1.63 mmol) in
5 mL of THF was then added dropwise via pipet, and the
solution was stirred for 2 h at room temperature. The volatile
components were removed in vacuo, and the residue was
extracted with 100 mL of THF, the extract was filtered through
Celite, and the Celite was washed with 3 × 50 mL of THF.
The product is crystallized by adding 2 volumes of pentane to
a concentrated THF solution and storing at -40 °C overnight.
The deep purple solid was collected on a frit, washed with 50
mL of pentane, and dried in vacuo: yield 4.57 g, 83%; 1H NMR
(C6D6) δ 19.4 (s, 3, NMe), 6.21, 1.54, 1.16, 0.97, -24.9, -30.8,
-97.7, -103.7; 19F NMR (C6D6) δ -54.5 (s).
[Bu 4N]{[CF3NMe]MoCl3} (12b). A 2.63 g amount of H2[CF3-
NMe] (6.5 mmol) and 2.49 g of MoCl4(Et2O)2 (6.5 mmol) were
combined in 80 mL of THF and stirred for 30 min. A 2.0 mL
portion of triethylamine (14.3 mmol) in 4 mL of THF was
added dropwise via pipet and the mixture stirred for 1 h. The
purple solution was filtered through Celite and washed with
2 × 40 mL of THF. A 1.98 g amount of tetrabutylammonium
chloride (7.1 mmol) was added as a solid to the solution, and
the mixture was stirred vigorously for 15 h. The solution was
then stripped to a dark purple solid and extracted with 200
mL of toluene, and the extract was filtered through Celite,
which was washed with 3 × 40 mL of additional toluene.
[Bu4N]{[CF3NMe]MoCl3} was isolated as a purple powder by
concentration of the solution and addition of pentane followed
by storage at -40 °C. The purple solid was dried thoroughly
in vacu: yield 4.18 g (76%); 1H NMR (C6D6, 500 MHz) δ 28.16,
25.95, 19.37 (s, 3, NMe), 6.29, 4.67, 1.1 (NBu), 1.0 (NBu), 0.87
(NBu), 0.78(NBu), -2.33, -30.9, -99.4, -105.4; 19F NMR
(C6D6) δ -54.8. Anal. Calcd for C35H55N4F6Cl3Mo: C, 49.66;
H, 6.51; N, 6.48; Cl, 12.61. Found: C, 49.57; H, 6.54; N, 6.61;
Cl, 12.54.
[CF 3NMe]Mo(CH2SiMe3)2 (13). A 3.036 g amount (4.3
mmol) of [Et3NH]{[CF3NMe]MoCl3} was dissolved in 25 mL
of THF and chilled to -78 °C. To the purple solution was added
a solution of ((trimethylsilyl)methyl)magnesium chloride (16.7
mL, 0.8 M in Et2O, 13.3 mmol, 3.1 equiv) with stirring. The
solution turned dark green over 4 h, and the color darkened
to deep red as the reaction mixture was naturally warmed to
room temperature. After 15 h all volatile components were
removed, and the residue was extracted into pentane, the
extract was filtered through Celite, and the Celite was washed
with pentane until the washings were colorless. The solution
was concentrated to ca. 30 mL and filtered through Celite a
second time. The solution was concentrated to 15 mL and
stored at -40 °C for 2 days, affording dark blocks of crystalline
[CF3NMe]Mo(CH2SiMe3)2, which were dried in vacuo: yield
1.6 g (55%). A second crop yielded an additional 180 mg of
[F 3NMe]W(CH2SiMe3)(CSiMe3) (11b). A solution of Me3-
SiCH2MgCl (0.71 mL, 1.0 M in Et2O) was added to a solution

678 Organometallics, Vol. 23, No. 4, 2004
Cochran et al.
product, for a total yield of 62%. The complex has also been
synthesized in the same fashion and in similar yield from
[Bu4N][{[CF3NMe]MoCl3}] and 2.1 equiv of alkylmagnesium
reagent. 1H NMR (C6D6): δ 15.8, 13.25 (s, 3, NMe), 11.68, 10.9,
5.43, 3.8, 3.5 (br s,9, SiMe3), 1.3, 1.2 (br s, 9, SiMe3), -46.3,
-60.1. 19F NMR (C6D6): δ -55.8. Anal. Calcd for C27H41N3F6-
Si2Mo: C, 47.88; H, 6.06; N, 6.14. Found: C, 48.13; H, 6.13;
N, 6.24.
[CF 3NMe]Mo(CH2CMe3)Cl (14). A sample of 12a (140 mg,
0.2 mmol) was dissolved in 12 mL of THF, and the solution
was chilled to -30 °C. A solution of neopentylmagnesium
chloride (0.21 mL, 2.1 M in Et2O, 0.44 mmol, 2.2 equiv) was
then added. After the reaction mixture was stirred for 30 min,
the color changed to dark green. All volatile components were
removed in vacuo, and the residue was taken up in a minimum
of diethyl ether. 1,4-Dioxane was added, the solution was
filtered through Celite, and the Celite was washed with 4 mL
of ether. The filtrate was concentrated in vacuo, and pentane
was added. After 18 h at 30 °C, dark green crystals were
isolated, rinsed with a minimum of pentane, and dried in
vacuo: yield 98 mg (89%); 1H NMR (C6D6) δ 15.67, 13.5 (br s,
3, NMe), 4.33 (2, s) 3.93 (br s, 9, CH2CMe3), -51 (br s, 2), -88
(br s, 2); 19F NMR (C6D6) δ -59.8. Anal. Calcd for C24H30N3F6-
ClMo: C, 47.64; H, 5.11; N, 6.58. Found: C, 47.58; H, 4.99; N,
6.94.
[CF3NMe]Mo(CCMe3)(CH2CMe3) (15). [Et3NH]{[CF3NMe]-
MoCl3} (220 mg, 0.31 mmol) was dissolved in 25 mL of THF,
and the solution was chilled to -30 °C. To the purple, cold
solution was added 0.55 mL of neopentylmagnesium chloride
in ether (1.76 M, 0.96 mmol) with stirring. After 2 h all
volatiles were removed from the dark yellow solution. The
residue was extracted into toluene, and 1,4-dioxane was added.
The mixture was stirred for 20 min and filtered through Celite,
and the Celite was washed with toluene until the washings
were clear (∼25 mL). The toluene was removed in vacuo to
leave a brown solid. This was taken up in a minimum of ether,
and pentane was added. Storage of the solution at -30 °C for
3 days afforded yellow crystalline [CF3NMe]Mo(CCMe3)(CH2-
CMe3): yield 126 mg (63%); 1H NMR (C6D6) δ 7.47 (s, 2, C6H4),
7.14 (d, 2, C6H4), 7.02-6.94 (m, 4, C6H4), 3.34 (m, 2, CH2), 3.25
(m, 2, CH2), 2.27 (m, 2, CH2), 2.04 (m, 2, CH2), 2.03 (s, 3, NMe),
1.64 (s, 2, CH2CMe3), 1.47, (s, 9, CCMe3), 0.52 (s, 9, CCMe3);
13C (tol-d8) δ 307.7 (MoCCMe3), 165.3, 137.7, 130.8 (J CF ) 31.6
Hz), 125.58, 125.1 (J CF ) 272.6 Hz), 121.5, 119.95, 69.90, 59.38,
55.13, 49.95, 43.45, 37.17, 34.98, 29.20; 19F NMR (C6D6) δ
-61.7 ppm.
The THF solution was freeze-pump-thaw degassed several
times. Once properly degassed (∼10-6 Torr), the THF solution
was added to solid [Et3NH]{[F3NMe]MoCl3} and then frozen
to -196 °C. The reaction mixture was allowed to thaw to room
temperature and stirred for 4 h. The reaction mixture was
again frozen in a liquid nitrogen bath and opened to the
Toepler pump. Gas collection occurred over the course of 3 h.
The gas was passed through three U-tubes, all of which were
immersed in liquid nitrogen, before reaching the pump. This
step ensured the removal of any condensable gases, reducing
error in the experiment. The reaction setup was then closed
to the pump and allowed to thaw for a second round of
degassing before collecting again. This process was repeated
a third time to ensure complete gas collection. In the end, 91
mmHg of gas was collected into a calibrated volume of 11.9
mL at 23.7 °C. The amount of gas collected was found to be
0.0585 mmol, as determined through the ideal gas law (PV )
nRT). The gas was then completely burned over a CuO catalyst
at 320 °C to verify its composition. A control experiment
demonstrated the efficiency of the pump by collecting a
predetermined amount of hydrogen in 94% yield.
To confirm the production of [F3NMe]Mo(CH2CMe3)(CCMe3),
the product solution was then brought back into the glovebox,
and the total volume was measured to be 4.09 mL. A 0.59 mL
aliquot was transferred to an NMR tube, and 4 µL of 4-fluo-
robromobenzene was added as an internal standard. The 19F
NMR spectrum of this mixture was acquired, and the number
of moles of [F3NMe]Mo(CH2CMe3)(CCMe3) produced was cal-
culated from the relative intensities of the resonances corre-
sponding to the meta fluorine resonance of the [F3NMe]2-
ligand aryl rings to that of 4-fluorobromobenzene. A value of
0.0656 mmol was calculated for the total amount of [F3NMe]-
Mo(CH2CMe3)(CCMe3) produced in the reaction. A yield of 90%
was found for the collected H2 (mmol of H2/mmol of [F3NMe]-
Mo(CH2CMe3)(CCMe3)).
Ack n ow led gm en t. R.R.S. thanks the National Sci-
ence Foundation (Grant No. CHE 9988766) for research
support and Peter J . Bonitatebus, J r., and William M.
Davis for assistance with X-ray studies.
Su p p or tin g In for m a tion Ava ila ble: Text giving experi-
mental details, labeled thermal ellipsoid drawings, and tables
giving crystal data and structure refinement details, atomic
coordinates, bond lengths and angles, and anisotropic dis-
placement parameters for [Et3NH]{[F5NMe]WCl3, [F5NMe]Mo-
(CH2CMe3)Cl, and [Bu4N]{[CF3NMe]MoCl3}. This material is
available free of charge via the Internet at http://pubs.acs.org.
Crystallographic data for [Et3NH]{[F5NMe]MoCl3}, [F5NMe]-
MoMe2, and [F3NMe]Mo(CH2CMe3)(CCMe3) were deposited as
Supporting Information in earlier publications.22,23
Mea su r em en t of Hyd r ogen Evolu tion . Inside the glove-
box, a solution of Me3CCH2MgCl (0.21 mL, 1.75 M in Et2O)
was diluted with THF (4 mL). The THF solution was trans-
ferred to a reaction flask and attached to one end of a swivel
frit. At the other end of the swivel frit was placed a second
reaction flask containing a stir bar and [Et3NH]{[F3NMe]-
MoCl3} (0.075 g, 0.1103 mmol). The reaction assembly was
taken out of the glovebox and attached to a high-vacuum line.
OM030638U