New piano stool cis-bis(organohydrazido) complexes of molybdenum. X-ray structure of [(η5-C5H5)Mo(NNPh2) 2(PPh3)]+CF3SO3 -

Article abstract of DOI:10.1021/om980092p

A two-step procedure for the synthesis of cationic organometallic complexes containing the robust cis-{Mo(NNRPh)₂}²⁺ core (R = Me, Ph) is reported. The reaction of silver triflate, AgOTf (OTf^-= CF₃SO₃^-), with an equimolar amount of [Mo(NNMePh)₂Cl₂(PPh₃)₂] (1) or [Mo(NNPh₂)₂Cl₂(PPh₃)] (2) (in the presence of 1 equiv of PPh₃) in CH₂Cl₂/CH₃CN yields ionic intermediates formulated as [Mo(NNRPh)₂Cl(PPh₃)₂]⁺OTf ^- (R = Me, [3]⁺OTf^-; R = Ph, [4]⁺OTf^-), which give ionic products formulated as [(η⁵-C₅H₅)Mo(NNRPh)₂(PPh ₃)]⁺OTf^- (R = Me, [5]⁺OTf^-; R = Ph, [6]⁺OTf^-) upon reaction with excess NaCp in THF. These compounds have been characterized by IR, UV-visible, and NMR spectroscopy and cyclic voltammetry. The molecular structure of [6]⁺OTf^- has also been determined by X-ray diffraction.

Full text of DOI:10.1021/om980092p

3728
Organometallics 1998, 17, 3728-3732
New P ia n o Stool cis-Bis(or ga n oh yd r a zid o) Com p lexes of
Molybd en u m . X-r a y Str u ctu r e of
-
[(η5-C5H5)Mo(NNP h 2)2(P P h 3)]+CF 3SO3
Carolina Manzur,† David Carrillo,*,† Francis Robert,‡,§ Pierre Gouzerh,*,‡ and
J ean-Rene´ Hamon*,|
Laboratorio de Quı´mica Inorga´nica, Instituto de Qu´ımica, Universidad Cato´lica de
Valparaı´so, Av. Brasil 2950, Valpara´ıso, Chile, Laboratoire de Chimie des Me´taux de
Transition, URA CNRS No. 419, Universite´ Pierre et Marie Curie, 4, Place J ussieu,
75252 Paris Cedex 05, France, and UMR CNRS 6509 “Organome´talliques et Catalyse: Chimie
et Ele´ctrochimie Mole´culaires”, Universite´ de Rennes 1, Campus de Beaulieu,
35042 Rennes Cedex, France
Received February 12, 1998
A two-step procedure for the synthesis of cationic organometallic complexes containing
the robust cis-{Mo(NNRPh)2}2+ core (R ) Me, Ph) is reported. The reaction of silver triflate,
AgOTf (OTf-) CF3SO3-), with an equimolar amount of [Mo(NNMePh)2Cl2(PPh3)2] (1) or
[Mo(NNPh2)2Cl2(PPh3)] (2) (in the presence of 1 equiv of PPh3) in CH2Cl2/CH3CN yields ionic
intermediates formulated as [Mo(NNRPh)2Cl(PPh3)2]+OTf- (R ) Me, [3]+OTf-; R ) Ph,
[4]+OTf-), which give ionic products formulated as [(η5-C5H5)Mo(NNRPh)2(PPh3)]+OTf- (R
) Me, [5]+OTf-; R ) Ph, [6]+OTf-) upon reaction with excess NaCp in THF. These
compounds have been characterized by IR, UV-visible, and NMR spectroscopy and cyclic
voltammetry. The molecular structure of [6]+OTf- has also been determined by X-ray
diffraction.
In tr od u ction
W,4,6,18 V,20 Nb,20 and Ta.20 However, to the best of our
knowledge, organometallic compounds containing such
a unit have not been reported.21 To date, only two types
of related binuclear compounds containing either two
equivalent (µ-η1),22,23 or nonequivalent (µ-η1 and µ-η2),24-26
NNR2 ligands have been described.
A number of coordination complexes containing the
cis-{M(NNRR′)2}z+ functional unit with two η1-bonded
hydrazido ligands (R, R′ ) alkyl, aryl) have been
characterized, particularly when M ) Mo,1-16 Re,17-19
We have recently reported the synthesis of molybde-
num complexes of general formula [Mo(NNRPh)2Cl2-
(PMexPh3-x)n] (R ) Me, Ph; x ) 0, 1, 2; n ) 1, 2),11 from
molybdenum complexes containing both the NNRPh
and NHNRPh ligands.27 Now, in view of the reactivity
of [Mo(NNMe2)2Cl(PPh3)2]+ toward various nucleo-
philes,4 we have investigated the potential of [Mo-
(NNMePh)2Cl2(PPh3)2] (1) and [Mo(NNPh2)2Cl2(PPh3)]
(2) in the synthesis of organometallic compounds con-
* To whom correspondence should be addressed.
† Universidad Cato´lica de Valpara´ıso.
‡ Universite´ Pierre et Marie Curie.
§ Deceased on February 5, 1998.
| Universite´ de Rennes 1.
(1) Chatt, J .; Crichton, B. A. L.; Dilworth, J . R.; Dahlstrom, P.;
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S0276-7333(98)00092-2 CCC: $15.00 © 1998 American Chemical Society
Publication on Web 07/22/1998

New Piano Stool Complexes of Mo
Organometallics, Vol. 17, No. 17, 1998 3729
taining the cis-{Mo(NNRPh)2}2+ unit (R ) Me, Ph). In
this context, we will now report on (i) the synthesis and
characterization of two new bis(organohydrazido)mo-
lybdenum complexes, [Mo(NNRPh)2Cl(PPh3)2]+OTf- (R
) Me, [3]+OTf-; Ph, [4]+OTf-), and the first two mem-
bers of a new class of organometallics compounds,
formulated as [(η5-C5H5)Mo(NNRPh)2(PPh3)]+OTf- (R
) Me, [5]+OTf-; R ) Ph, [6]+OTf-) and (ii) their full
spectroscopic characterizations, including the crystal
and molecular structure of [6]+OTf-.
1150 cm-1 for [3]+OTf- and 1273 and 1155 cm-1 for
[4]+OTf-.31,32 These data indicate unambiguously that
the triflate anions are not coordinated.32
The electronic spectra of [3]+OTf- and [4]+OTf- show
two bands of similar intensities at 354 and 380 nm and
at 358 and 404 nm, respectively. In addition, both
spectra show a shoulder at ca. 270 nm. Absorption in
the 260-360 nm region has been attributed to the {Mo-
(NNRPh)2}2+ chromophore.33
Secon d Step . Syn th eses of th e Or ga n om eta llic
Com p ou n d s [Cp Mo(NNRP h )2(P P h 3)]+OTf- (R )
Me, [5]+OTf-; R ) P h , [6]+OTf-). These syntheses
were performed at room temperature in THF by reaction
of [3]+OTf- and [4]+OTf-, respectively, with NaCp in
excess. These reactions involve the displacement of the
chloro and of one phosphine ligands by a cyclopentadi-
enyl ring. The compounds [5]+OTf- and [6]+OTf- were
isolated as air-stable solids in 34% and 39% yields,
respectively. Orange crystals of [6]+OTf- were obtained
from CH2Cl2 solutions carefully layered with n-hexane.
Resu lts a n d Discu ssion
The syntheses of the organometallic compounds
[5]+OTf- and [6]+OTf- have been conveniently achieved
from the neutral complexes 1 and 2, in a two-step
procedure.
F ir st Step . Syn th eses a n d Ch a r a cter iza tion s of
t h e In t er m ed ia t e Com p lexes [Mo(NNR P h )2Cl-
(P P h 3)2]+OTf- (R ) Me, [3]+OTf-; R ) P h , [4]+OTf-).
The synthesis of [3]+OTf- was carried out at room
temperature by reaction of Ag+OTf- with an equimolar
amount of 1 in CH2Cl2/CH3CN (2:1). In this way, one
chloro ligand of 1 is removed, which affords the stable
ionic species [Mo(NNPhMe)2Cl(PPh3)2]+OTf- in high
yield (96%, before recrystallization). However, the
similar reaction of Ag+OTf- with 2 gives a complex
mixture, from which [4]+OTf- was isolated in low yield
through successive recrystallizations. It was assumed
that the unstable intermediate [Mo(NNPh2)2Cl(PPh3)]+
transforms partially into the stable pentacoordinated
product [Mo(NNPh2)2Cl(PPh3)2]+ ([4]+). Consistent with
this hypothesis, the yield of [4]+OTf- was significantly
increased (91%, before recrystallization) when the reac-
tion was carried out in the presence of an equimolar
amount of PPh3. The cationic complexes [3]+ and [4]+
are similar to [Mo(NNMe2)2Cl(PPh3)2]+, which has been
authenticated by X-ray diffraction methods.4
1
The H NMR spectra of [5]+OTf- and [6]+OTf- show
a complex multiplet in the 6.80-7.80 ppm range,
corresponding to the phenyl proton resonances of the
hydrazido and phosphine ligands, and a singlet char-
acteristic of the Cp ligand at 6.10 and 5.67 ppm,
respectively. In addition, that of [5]+OTf- exhibits a
unique methyl proton resonance at 3.66 ppm, which
indicates the equivalence of both hydrazido ligands. The
13C NMR spectra of both compounds show also a
characteristic singlet for the carbons of the Cp ligand
at 102.6 and 103.0 ppm, respectively. On the other
hand, the 31P{1H} NMR spectra show the expected
singlet for the PPh3 ligand at 51.93 and 49.65 ppm,
respectively.
The IR spectra exhibit a characteristic medium-
intensity band at 1589 cm-1 due to the ν(NN) vibra-
tion.4,28-30 The characteristic strong bands due to the
ν(SO3) and ν(CF3) modes of the triflate counterions31,32
were observed at 1271 and 1150 cm-1, respectively,
which indicates that they are not coordinated.32 The
X-ray crystal structure of [6]+OTf- supports unambigu-
ously this conclusion (vide infra).
The compounds [3]+OTf- and [4]+OTf- were charac-
terized by 1H and 31P NMR, IR, and UV-visible
spectroscopy (for further details, see the Experimental
1
Section). The H NMR spectra of both complexes show
a complex multiplet in the 6.30-7.60 ppm range,
corresponding to the phenyl proton resonances of the
hydrazido and phosphine ligands. In addition, that of
[3]+OTf- shows a unique singlet at 3.51 ppm, indicating
the equivalence of the hydrazido methyl groups. The
31P{1H} NMR spectra of [3]+OTf- and of [4]+OTf- show
only one signal at 29.52 and 29.72 ppm, respectively,
indicating the magnetic equivalence of the phosphorus
atoms of both PPh3 ligands, in solution at room tem-
perature. The spectroscopic similarities between [3]+
and [4]+ and [Mo(NNMe2)2Cl(PPh3)2]+ 4 favor a trigonal-
bipyramidal geometry around the metal, in which the
two axial bulky phosphines adopt a trans arrangement.
The IR spectra of both complexes show a character-
istic medium-intensity band at 1588 cm-1, which has
been attributed to the ν(NN) vibration.4,28-30 The
characteristic strong bands due to the ν(SO3) and ν(CF3)
modes of the triflate anion were observed at 1264 and
The electronic spectra of [5]+OTf- and [6]+OTf-
exhibit three bands at 284, 316, and 388 nm and at 290,
322, and 384 nm, respectively. The bands in the 280-
330 nm region have been attributed to the {Mo(N-
NRPh)2}2+ chromophore.33
Cyclic voltammetry studies were carried out in CH3-
CN at a platinum electrode at scan rates varying from
10 to 500 mV s-1
. The electrochemical behavior of
[5]+OTf- and [6]+ OTf- is similar to that of compounds
1 and 2 and other related complexes.11 Both complexes
show a reduction peak at -1.70 and -1.64 V, respec-
tively, and an oxidation peak at +0.86 and +1.01 V vs
SCE, respectively. In the range of scan rates studied
both processes appear to be irreversible. The number
of electrons transferred was estimated to be 1 by
comparison to the ferrocene oxidation under the same
experimental conditions.
X-r a y Str u ctu r e of [Cp Mo(NNP h 2)2(P P h 3)]+OTf-
([6]+OTf-). Crystallographic data for [6]+OTf- are
(28) Nicholson, T.; Zubieta, J . J . Chem. Soc., Chem. Commun. 1985,
365.
(31) Bu¨rger, H.; Burczyk, K.; Blaschette, A. Monatsh. Chem. 1970,
101, 102.
(29) Shaikh, S. N.; Zubieta, J . Inorg. Chim. Acta 1986, 115, 19.
(30) Dilworth, J . R.; Morton, D. L. Transition Met. Chem. 1987, 12,
41.
(32) Lawrance, G. A. Chem. Rev. 1986, 86, 17.
(33) Shaikh, S. N.; Zubieta, J . Inorg. Chem. 1986, 25, 4613.

3730 Organometallics, Vol. 17, No. 17, 1998
Manzur et al.
F igu r e 1. CAMERON plot of [6]+ with the atom-labeling scheme. The hydrogen atoms and the OTf- anion have been
omitted for clarity.
Ta ble 1. Cr ysta llogr a p h ic Da ta for
Com p ou n d [6]+OTf-
Ta ble 2. Selected In ter a tom ic Dista n ces (Å)
for [6]+OTf-
-
formula
fw
space group
a, Å
b, Å
c, Å
R, deg
â, deg
γ, deg
V, Å3
Z
T, °C
[(η5-C5H5)Mo(NNPh2)2(PPh3)]+CF3SO3
Mo(1)-N(2)
N(2)-N(3)
1.816(4)
1.309(6)
1.416(7)
1.423(7)
2.382(4)
2.342(6)
2.361(6)
1.828(5)
1.817(5)
1.382(9)
1.406(9)
Mo(1)-N(16)
N(16)-N(17)
N(3)-C(10)
N(17)-C(24)
Mo(1)-C(31)
Mo(1)-C(33)
Mo(1)-P(35)
P(35) -C(36)
C(30)-C(31)
C(32)-C(33)
C(30)-C(34)
1.797(4)
1.312(6)
1.450(7)
1.444(7)
2.370(6)
2.338(6)
2.476(1)
1.818(5)
1.406(9)
1.427(9)
1.399(9)
936.81
P1h
12.414(2)
14.105(7)
14.304(2)
81.73(3)
66.10(1)
78.94(3)
2241
2
20
0.710 69
1.39
4.2
2-50
N(3)-C(4)
N(17)-C(18)
Mo(1)-C(30)
Mo(1)-C(32)
Mo(1)-C(34)
P(35) -C(42)
P(35) -C(48)
C(31)-C(32)
C(33)-C(34)
Ta ble 3. Selected Bon d An gles (d eg) for [6]+OTf-
λ, Å
µ(Mo KR), cm-1
N(2)-Mo(1)-N(16)
106.9(2) N(2)-Mo(1)-C(30)
97.1(2)
93.8(2)
121.3(2)
151.2(2)
128.2(2)
92.4(1)
F
calcd, g cm-3
N(16)-Mo(1)-C(30) 149.7(2) N(2)-Mo(1)-C(31)
N(16)-Mo(1)-C(31) 123.6(2) N(2)-Mo(1)-C(32)
2θ range, deg
octants collected
scan width, deg
diffractometer
no. of unique rflns
no. of rflns with
I > 3σ(I)
-13 to +14; -16 to +16; 0-16
0.8 + 0.345 tan θ
Enraf-Nonius CAD4F
7865
N(16)-Mo(1)-C(32)
N(16)-Mo(1)-C(33)
93.8(2) N(2)-Mo(1)-C(33)
94.0(2) N(2)-Mo(1)-C(34)
N(16)-Mo(1)-C(34) 124.8(2) N(2)-Mo(1)-P(35)
N(16)-Mo(1)-P(35)
93.9(1) C(30)-Mo(1)-P(35) 103.5(2)
5829
C(31)-Mo(1)-P(35) 137.9(2) C(32)-Mo(1)-P(35) 141.2(2)
C(33)-Mo(1)-P(35) 106.0(2) C(34)-Mo(1)-P(35)
86.9(2)
34.1(2)
34.8(2)
abs cor
DIFABS
550
0.053
0.056
C(30)-Mo(1)-C(31)
C(32)-Mo(1)-C(33)
34.4(2) C(31)-Mo(1)-C(32)
35.5(2) C(33)-Mo(1)-C(34)
no. of variables
Ra
Mo(1)-P(35)-C(36) 112.2(2) C(36)-P(35)-C(48) 104.6(2)
Mo(1)-P(35)-C(48) 114.7(2) C(36)-P(35)-C(42) 105.7(2)
Mo(1)-P(35)-C(42) 114.9(2) C(42)-P(35)-C(48) 103.7(2)
b
Rw (w ) 1.0)
a
b
2 1/2
R ) ∑||Fo| - |Fc||/∑|Fo|. Rw )[∑w(|Fo| - |Fc|)2/∑wFo
] .
Mo(1)-N(2)-N(3)
N(2)-N(3)-C(10)
Mo(1)-N(16)-N(17) 168.1(4) N(16)-N(17)-C(18) 119.9(4)
N(16)-N(17)-C(24) 118.5(4) C(18)-N(17)-C(24) 121.6(4)
C(30)-C(33)-C(32)
C(32)-C(33)-C(34)
C(31)-C(30)-C(34)
158.9(4) N(2)-N(3)-C(4)
118.2(4) C(4)-N(3)-C(10)
120.3(5)
121.1(4)
given in Table 1, and selected bond distances and angles
are listed in Tables 2 and 3, respectively. A CAMERON
plot of [6]+ is shown in Figure 1. The crystal structure
consists of discrete ions with two formula units in the
unit cell. The cation is approximately octahedrally
coordinated by the η5-C5H5 ligand, the two η1-bonded
hydrazido ligands, and the phosphine ligand. It has the
familiar distorted-piano-stool geometry found previously
for [CpMo(NNC6H4Me-p)(NNC6H4F-p)(PPh3)]+.34,35 The
short Mo-N (1.816(4) and 1.797(4) Å) and N-N dis-
108.6(6) C(31)-C(32)-C(33) 108.1(6)
107.0(6) C(33)-C(34)-C(30) 108.3(6)
107.9(6)
tances (1.309(6) and 1.312(6) Å) and the near-planarity
of the Mo-N-N-C2 moieties (maximum deviation from
the mean planes 0.057 Å) indicate extensive electronic
delocalization throughout the MoNNPh2 systems. These
parameters are similar for most of the complexes
containing the cis-{Mo(NNRR′)2}2+ unit.36 The depar-
ture from linearity of the Mo-N-N grouping (Mo-N-N
) 158.9(4) and 168.1(4)°) is similar to that observed in
(34) Carroll, W. E.; Condon, D.; Deane, M. E.; Lalor, F. J . J .
Organomet. Chem. 1978, 157, C58.
(35) Ferguson, G.; Ruhl, B. L.; Parvez, M.; Lalor, F. J .; Deane, M.
E. J . Organomet. Chem. 1990, 381, 357.

New Piano Stool Complexes of Mo
Organometallics, Vol. 17, No. 17, 1998 3731
[Mo(NNMePh)2Cl2(PPh3)2]11 and possibly arises from
intramolecular nonbonding contact interactions. On the
other hand, the origin of the slight asymmetry observed
in the bonding mode of the cyclopentadienyl ligand is
not clear. Indeed, both the longest (Mo(1)-C(30) )
2.382(6) Å) and the shortest (Mo(1)-C(33) ) 2.338(6)
Å) Mo-C bonds are approximately trans to the hy-
drazido ligands.
Although such complexes have been considered for a
long time as containing hydrazido(2-) ligands, a recent
theoretical investigation of mono- and bis(hydrazido)
metal complexes36 indicates that, taken as a whole, two
cis formally hydrazido(2-) ligands act as a 10-electron
system. Therefore, [3]+and [4]+ are 16-electron com-
plexes, while [5]+ and [6]+ fulfill the 18-electron rule.
In these compounds, the actual NNR2 oxidation state
is likely closer to 1- rather than to 2-.36 Such a ligand
formal charge leads us to consider molybdenum in the
IV (d2) oxidation state.
were 1.0 mM in the compound under study and 0.1 M in the
supporting electrolyte n-Bu4N+PF6-. Under these experimen-
tal conditions the FeCp2/FeCp2+ couple was located at 0.39 V.
P r ep a r a tion of [Mo(NNMeP h )2Cl(P P h 3)2]+OTf- ([3]+-
OTf-). To a solution of 1 (0.28 g, 0.30 mmol) in CH2Cl2/CH3-
CN (2:1, 15 mL) was added AgOTf (0.075 g, 0.30 mmol). The
mixture was stirred for 2.0 h at room temperature and filtered
through Celite. The solid was washed several times with CH2-
Cl2/CH3CN (2:1), and the combined filtrates were evaporated
to dryness under vacuum. The residue was stirred in CH2-
Cl2/Et2O (1:10, 30 mL) for 1.5 h and then filtered off. The solid
was washed with diethyl ether, dried under vacuum, and
recrystallized as follows: the crude product was dissolved in
CH2Cl2 and then diethyl ether was added with stirring until
a brown impurity precipitated. An additional amount of
diethyl ether was added to the filtrate. Cooling to -15 °C gave
a pale green microcrystalline solid. Further recrystallization
was carried out in CH2Cl2, which was layered with n-hexane
and cooled to -15 °C. Yield before recrystallization: 0.29 g
(96%). Mp: 181 °C dec. Anal. Calcd for C51H46ClF3MoN4-
O3P2S: C, 58.6; H, 4.44. Found: C, 58.8; H, 4.60. UV-vis
(CH2Cl2; λmax, nm (log ꢀ)): 280 sh (4.38); 354 (4.25); 380 sh
(4.20). IR (cm-1, KBr): 3056 (w), ν(CH) arom; 2929 (w), ν-
(CH) aliph; 1587 (m), ν(NN); 1480 (m, split), ν(CC) arom; 1264
(vs), ν(SO3); 1150 (m), ν(CF3). 1H NMR (CDCl3): δ 3.51 (s,
6H, 2CH3N); 6.80-7.53 (m, 40H, 8C6H5). 31P{1H} NMR
(CDCl3): δ 29.52 (s).
Con clu d in g Rem a r k s
The two-step procedure described herein provides a
convenient method for the preparation, under mild
conditions, of [5]+OTf- and [6]+OTf- from 1 and 2.
These compounds represent the first examples of orga-
nometallic derivatives that contain the cis-{Mo(NNR-
Ph)2}2+ moiety (R ) Me, Ph), where the organodinitro-
gen ligands are considered as potential models for
NNH2, which is a proven intermediate in the conversion
of N2 into NH3 at a mononuclear site.37 Furthermore,
the intermediates [3]+OTf- and [4]+OTf- open a facile
synthetic route to a number of coordination or organo-
metallic compounds, depending on the nature of the
incoming ligands, and we are currently investigating
along this line.
P r epar ation of [Mo(NNP h 2)2Cl(P P h 3)2]+OTf- ([4]+OTf-).
To a mixture of 2 (0.23 g, 0.30 mmol) and PPh3 (0.076 g, 0.30
mmol) suspended in CH2Cl2/CH3CN (2:1, 15 mL) was added
AgOTf (0.075 g, 0.30 mmol). The crude product was isolated
as described above for [3]+OTf- and then redissolved in CH2-
Cl2. The solution was filtered off, and diethyl ether was added
to the filtrate, which was cooled to -15 °C. The resulting
crystalline solid was finally dissolved in CH2Cl2 layered with
n-hexane to afford pure [4]+OTf- as a pale green microcrys-
talline solid. Yield before recrystallization: 0.30 g (91%).
Mp: 190 °C dec. Anal. Calcd for C61H50ClF3MoN4O3P2S: C,
62.7; H, 4.31; N, 4.79. Found: C, 62.4; H, 3.99; N, 4.76. UV-
vis ((CH2Cl2; λmax, nm (log ꢀ)): 260 sh (4.69); 358 (4.27); 404
(4.19). IR (cm-1, KBr): 3056 (w), ν(CH) arom; 1588 (m), ν-
(NN); 1483 (s), ν(CC); 1272 (vs), ν(SO3); 1150 (m), ν(CF3). 1H
NMR (CDCl3): 6.35-7.50 (m, C6H5). 31P{1H} NMR (CDCl3):
29.72 (s). MS (positive Cs-FAB, m-nitrobenzylic alcohol): calcd
m/z for C60H50ClMoN4P2, C+, 1021.2263; obsd 1021.2265.
P r ep a r a t ion of [Cp Mo(NNMeP h )2(P P h 3)]+OTf- ([5]+-
OTf-). To a 0.21 g (0.20 mmol) sample of [3]+OTf- dissolved
in 20 mL of THF was added 0.20 mL of NaCp 2.0 M in THF
(0.40 mmol). The mixture was stirred vigorously for 45 min
at room temperature. Then the solution was evaporated to
dryness under vacuum. The residue was extracted three times
with 10 mL portions of CH2Cl2, and the extracts were filtered
through Celite. The filtrate was concentrated to a final volume
of 10 mL and layered with diethyl ether. Orange microcrystals
appeared after 1 week at -15 °C. Yield: 0.056 g (34.1%).
Mp: 191 °C. Anal. Calcd for C38H36F3MoN4O3PS: C, 56.2;
H, 4.47. Found: C, 55.5; H, 4.50. UV-vis ((CH2Cl2; λmax, nm,
Exp er im en ta l Section
All manipulations were carried out on a vacuum/nitrogen
line using standard Schlenk techniques. Cyclopentadienyl-
sodium (NaCp) 2.0 M in THF, silver triflate (AgOTf-), and
tetrabutylammonium hexafluorophosphate (n-Bu4N+PF6-) were
purchased from commercial sources and used as received.
Reagent grade solvents were dried and distilled under nitro-
gen by standard methods prior to use. The compounds
[Mo(NNMePh)2Cl2(PPh3)2] and [Mo(NNPh2)2Cl2(PPh3)] were
prepared as described elsewhere.11 IR spectra were obtained
as KBr disks on a Perkin-Elmer Model 1600 FT-IR spectro-
photometer. 1H, 13C, and 31P NMR spectra were recorded in
CDCl3 on a Bruker FT AC/200P spectrometer. 1H and 13C
NMR spectra were referenced to Me4Si as an external stan-
dard. 31P NMR chemical shifts are reported relative to an
external standard of 85% H3PO4. Mass spectra were recorded
in a high-resolution ZabSpec TOF VG Analytical spectrometer
operating in the FAB+ mode. Ions were produced with the
standard Cs+ gun at ca. 8 kV, and 3-nitrobenzyl alcohol (NBA)
was used as the matrix. Melting points were determined by
using a Kofler apparatus. Cyclic voltammetry studies were
carried out with a homemade potentiostat of conventional
design, using a standard three-electrode setup with platinum
working and auxiliary electrodes and an aqueous saturated
calomel electrode (SCE) as the reference. CH3CN solutions
(log ꢀ)): 284 (4.42); 316 sh (4.30); 388 sh (4.05). IR (cm-1
,
KBr): 3060 (w), ν(CH) arom; 2931 (w), ν(CH) aliph; 1589 (m),
ν(NN); 1471 (m), ν(CC) arom; 1271 (vs), ν(SO3); 1150 (m), ν-
(CF3). 1H NMR (CDCl3): δ 3.66 (s, 6 H, 2CH3); 6.10 (s, 5 H,
C5H5); 7.08-7.78 (m, 25 H, 5C6H5). 31P{1H} NMR (CDCl3): δ
51.93 (s). 13C NMR (CDCl3): δ 43.41 (s, CH3); 102.6 (br s,
C5H5); 116.3, 125.2, 129.1, 129.2, 129.4, 131.6, 133.0, 133.2
(C6H5); 140.6 (OTf-).
P r epar ation of [CpMo(NNP h 2)2(P P h 3)]+OTf- ([6]+OTf-).
This compound was synthesized according to the procedure
described above using 0.36 g (0.20 mmol) of [4]+OTf- and 0.20
mL (0.40 mmol) of NaCp 2.0 M in THF. Suitable single
crystals for X-ray diffraction studies were obtained by slow
diffusion of n-hexane into a CH2Cl2 solution of the crude
(36) Kahlal, S.; Saillard, J .-Y.; Hamon, J .-R.; Manzur, C.; Carrillo,
D. J . Chem. Soc., Dalton Trans. 1998, 1229.
(37) Evans, D. J .; Henderson, R. A.; Smith, B. E. In Bioinorganic
Catalysis; Reedijk, J ., Ed.; Marcel Dekker: New York, 1994; p 89, and
references therein.

3732 Organometallics, Vol. 17, No. 17, 1998
Manzur et al.
product. Yield: 0.14 g (38.5%). Mp: 210 °C dec. Anal. Calcd
for C48H40F3MoN4O3PS: C, 61.5; H, 4.30. Found: C, 60.8; H,
4.38. UV-vis ((CH2Cl2; λmax, nm (log ꢀ)): 290 (4.57); 322 sh
(4.36); 384 sh (4.16). IR (cm-1, KBr): 3060 (w), ν(CH) arom;
1589 (m), ν(NN); 1486 (s), ν(CC) arom; 1271 (vs), ν(SO3); 1150
(s), ν(CF3). 1H NMR (CDCl3): δ 5.67 (s, 5H, C5H5); 6.80-7.56
(m, 35 H, 7C6H5). 31P{1H} NMR (CDCl3): δ 49.65 (s). 13C
NMR (CDCl3): δ 103.0 (C5H5); 129.4, 129.6, 130.2, 131.1,
131.90, 131.95, 133.1, 133.3 (C6H5); 205.3 (OTf-).
X-r a y Cr ysta llogr a p h ic An a lysis of [6]+OTf-. X-ray
data were recorded on an Enraf-Nonius CAD4F diffractometer
using graphite-monochromated Mo KR radiation. A crystal
of [6]+OTf- was mounted on a glass fiber. Lattice parameters
and the orientation matrix were obtained from a least-squares
fit of the setting angles of 25 accurately centered reflections.
Crystal data and data collection parameters are summarized
in Table 1. No significant variations were observed in the
intensities of two check reflections during data collection. The
data were corrected for Lorentz and polarization effects. An
empirical absorption correction using DIFABS was applied.38
All computations were performed using the PC version of
CRYSTALS.39 The structure was solved by direct methods and
refined with anisotropic thermal parameters for all non-
hydrogen atoms. Hydrogen atoms were included in fixed
positions in the last refinements, which gave R ) 0.053 and
Rw ) 0.056. Scattering factors and corrections for anomalous
dispersion were taken from the literature.40
Ack n ow led gm en t. We are grateful to Professor J .-
Y. Saillard (Universite´ de Rennes 1) for his assistance
and helpful discussions and Dr. P. Guenot (CRMPO,
Universite´ de Rennes 1) for mass spectrometry as-
sistance. D.C. and C.M. acknowledge financial support
of this work by the Fondo Nacional de Desarrollo
Cient´ıfico y Tecnolo´gico, (FONDECYT-Chile; Grant No.
1951088) and the Direccio´n General de Investigacio´n y
Postgrado, Universidad Cato´lica de Valpara´ıso, Val-
para´ıso, Chile.
Su p p or tin g In for m a tion Ava ila ble: Tables of atomic
coordinates, anisotropic thermal parameters, interatomic dis-
tances, and bond angles for [6]+OTf- (10 pages). Ordering
information is given on any current masthead page.
OM980092P
(39) (a) Watkin, D. J .; Carruthers, J . R.; Betteridge, P. W. Crystals
User Guide; Chemical Crystallography Laboratory, University of
Oxford: Oxford, U.K., 1988. (b) Pearce, L. J .; Watkin, D. J . CAMERON;
Chemical Crystallography Laboratory, University of Oxford: Oxford,
U.K., 1992.
(40) International Tables for X-ray Crystallography; Kynoch Press:
Birmingham, U.K., 1974; Vol. IV.
(38) Walker, N.; Stuart, D. Acta Crystallogr. 1983, 39A, 158.