The combination of organometallic {Mo(η3-allyl)(CO)2(phen)} fragments and hard aquo and hydroxo ligands: Controlled synthesis and structural characterization

Article abstract of DOI:10.1021/om0203882

The reaction of [Mo(η³-C₃H₄-Me-2)Cl(CO)₂(phen)] with NaBAr′₄ (Ar′ = 3,5-bis(trifluoromethyl)phenyl) and H₂O allowed the isolation of the aquo complex [Mo(η³-C₃H₄-Me-2)(OH₂)(CO)₂ (phen)]BAr′₄·2Et₂O (1). Deprotonation of 1 afforded a neutral monomeric hydroxo compound isolated as [{Mo(η³-C₃H₄-Me-2)(OH)(CO)₂(phen )}₂(μ-H₂O)] (2), which could be also obtained by reaction of [Mo(η³-C₃H₄-Me-2)Cl(CO)₂(phen)] with KOH in a biphasic CH₂Cl₂/ H₂O medium. The reaction of 1 and 2 afforded the binuclear hydroxo-bridged compound [{Mo(η³-C₃H₄-Me-2)(CO)₂(phen)} ₂(μ-OH)]BAr′₄ (3b) via nucleophilic substitution of water by the hydroxo ligand.

Full text of DOI:10.1021/om0203882

4934
Organometallics 2002, 21, 4934-4938
Th e Com bin a tion of Or ga n om eta llic
{Mo(η3-a llyl)(CO)2(p h en )} F r a gm en ts a n d Ha r d Aqu o a n d
Hyd r oxo Liga n d s: Con tr olled Syn th esis a n d Str u ctu r a l
Ch a r a cter iza tion
Dolores Morales, M. Elena Navarro Clemente,† J ulio Pe´rez,* Luc´ıa Riera, and
V´ıctor Riera
Departamento de Quı´mica Orga´nica e Inorga´nica-IUQOEM, Universidad de Oviedo-CSIC,
33071 Oviedo, Spain
Daniel Miguel
Departamento de Quı´mica Inorga´nica, Facultad de Ciencias, Universidad de Valladolid,
47071 Valladolid, Spain
Received May 13, 2002
The reaction of [Mo(η3-C3H4-Me-2)Cl(CO)2(phen)] with NaBAr′4 (Ar′ ) 3,5-bis(trifluoro-
methyl)phenyl) and H2O allowed the isolation of the aquo complex [Mo(η3-C3H4-Me-2)(OH2)-
(CO)2(phen)]BAr′4‚2Et2O (1). Deprotonation of 1 afforded a neutral monomeric hydroxo
compound isolated as [{Mo(η3-C3H4-Me-2)(OH)(CO)2(phen)}2(µ-H2O)] (2), which could be also
obtained by reaction of [Mo(η3-C3H4-Me-2)Cl(CO)2(phen)] with KOH in a biphasic CH2Cl2/
H2O medium. The reaction of 1 and 2 afforded the binuclear hydroxo-bridged compound
[{Mo(η3-C3H4-Me-2)(CO)2(phen)}2(µ-OH)]BAr′4 (3b) via nucleophilic substitution of water by
the hydroxo ligand.
In tr od u ction
We have recently reported the synthesis and prelimi-
nary reactivity studies of the new alkoxo complexes [Mo-
(η3-allyl)(OR)(CO)2(N-N)] (N-N ) bipyridine or phenan-
throline).2 As a continuation of these studies, we sought
to prepare the analogous hydroxo derivatives.3 Ex-
amples of complexes containing {Mo(η3-allyl)(CO)2}
fragments bridged by hydroxo groups are known;4
however, monometallic compounds of this kind have not
been reported. In fact, and despite the extensive studies
conducted on the chemistry of Mo(II) carbonyl com-
pounds,5 mononuclear hydroxo complexes remain un-
known, and the first mononuclear organometallic com-
pound of Mo(II) (without carbonyls) containing a terminal
hydroxo ligand, namely, [Mo(η5-C5H5)(OH)(PMe3)2], has
been reported only recently.6 On the other hand, in a
recent exploration of the catalytic activity of the Lewis-
acidic fragment {Mo(η3-allyl)(CO)2(phen)}+ (phen ) 1,-
10-phenanthroline) we found evidence suggesting the
Hard aquo and hydroxo ligands are prominent in
classical coordination chemistry due to the hard nature
of the metal fragments and to the widespread use of
water as solvent. In the organometallic chemistry of
transition metal fragments in low oxidation state, on
the other hand, complexes with these ligands are
relatively rare.1 Complexes with ligands both hard
(aquo, hydroxo) and soft (carbonyl and allyl are the ones
relevant to the work described here) bound to the same
metal center represent a borderline situation between
Werner-type complexes and organometallic compounds.
* Correspondence author. E-mail: japm@sauron.quimica.uniovi.es.
† Permanent address: ESIQIE-IPN, Edificio 6, 6217 UPALM, D.F.,
Mexico.
(1) Metal aquo complexes: (a) Hung, Y.; Kung, W.-J .; Taube, H.
Inorg. Chem. 1981, 20, 457. (b) Stebler-Ro¨thlisberger, M.; Hummel,
W.; Pittet, P.-A.; Burgi, H.-B.; Ludi, A.; Merbach, A. E. Inorg. Chem.
1988, 27, 1358. (c) Raab, K.; Olgemoeller, B.; Schloter, K.; Beck, W. J .
J . Organomet. Chem. 1981, 214, 81. (d) Laurenczy, G.; Helm, L.; Ludi,
A.; Merbach, A. Helv. Chim. Acta 1991, 74, 1236. (e) Alberto, R.; Egli,
A.; Abram, U.; Hegetschweiler, K.; Gramblich, V.; Schubiger, P. A. J .
Chem. Soc., Dalton Trans. 1994, 2815. (f) Funaioli, T.; Cavazza, C.;
Marchetti, F.; Fachinetti, G. Inorg. Chem. 1999, 38, 3361. (g) Crane,
T. W.; White, P. S.; Templeton, J . L. Inorg. Chem. 2000, 39, 1081, and
references therein. Metal hydroxo complexes: See ref 1g and: (h)
Bryndza, H. E.; Tam, W. Chem. Rev. 1988, 88, 1163. (i) Gilje, J . W.;
Roesky, H. W. Chem. Rev. 1994, 94, 895. (j) Grushin, V. V.; Alper, H.
Organometallics 1996, 15, 5242. (k) Tahmassebi, S. K.; McNeil, W. S.;
Mayer, J . M. Organometallics 1997, 16, 5342. (l) Boncella, J . M.; Eve,
T. M.; Rickman, B.; Abboud, K. A. Polyhedron 1998, 17, 725. (m) Ritter,
J . C. M.; Bergman, R. G. J . Am. Chem. Soc. 1998, 120, 6826. (n) Poli,
R.; Quadrelli, E. A. New J . Chem. 1998, 22, 435. (o) MacGregor, S. A.;
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A. J .; Holbert, T.; Sharp, T. P.; Sharp, P. R. Inorg. Chem. 1999, 38,
1563. For a rare example of chromium(0) hydroxo carbonyl complexes
see: McNeese, T. J .; Mueller, T. E.; Wierda, D. A.; Darensbourg, D.
J .; Delord, T. J . Inorg. Chem. 1985, 24, 3465.
(2) Hevia, E.; Pe´rez, J .; Riera, L.; Riera, V.; Miguel, D. Organome-
tallics 2002, 21, 1750.
(3) For a recent review containing hydroxo compounds see: Fulton,
J . R.; Holland, A. W.; Fox, D. J .; Bergman, R. G. Acc. Chem. Res. 2002,
35, 44.
(4) (a) Murdoch, H. D.; Henzi, R. J . Organomet. Chem. 1966, 5, 552.
(b) Prout, K.; Couldwell, M. C. Acta Crystallogr. 1977, B33, 2146. (c)
Breakell, K. R.; Rettig, S. J .; Storr, A.; Trotter, J . Can. J . Chem. 1979,
57, 139. (d) Lush, S.-F.; Wang, S.-H.; Lee, G.-H.; Peng, S.-M.; Wang,
S.-L.; Liu, R.-S. Organometallics 1990, 9, 1862. (e) Borgmann, C.;
Limberg, C.; Kaifer, E.; Pritzkow, H.; Zsolnai, L. J . Organomet. Chem.
1999, 580, 214. (f) Balzarek, C.; Weakley, T. J . R.; Kuo, L. Y.; Tyler,
D. R. Organometallics 2000, 19, 2927. (g) Borgmann, C.; Limberg, C.;
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(5) Baker, P. K. Adv. Organomet. Chem. 1995, 40, 45
(6) (a) Fettinger, J . C.; Kraatz, H.-B.; Poli, R.; Quadrelli, E. A. Chem.
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Quadrelli, E. A. J . Chem. Soc., Dalton Trans. 1999, 497.
10.1021/om0203882 CCC: $22.00 © 2002 American Chemical Society
Publication on Web 10/17/2002

Organometallic {Mo(η3-allyl)(CO)2(phen)} Fragments
Organometallics, Vol. 21, No. 23, 2002 4935
Sch em e 1
intervention of an aquo complex.7 The ionization of the
labile bis(nitrile) compound [Mo(η3-C3H5)Cl(CO)2(NCMe)2]
in water to give a putative cationic aquo complex has
been previously noted.8 In organotransition metal chem-
istry, where water is often excluded, and, in particular,
in the chemistry of molybdenum carbonyl compounds,
hydroxo and aquo complexes are obtained fortuitously
in most cases.1i The results of our search of a simple
and rational approach to the synthesis of {Mo(η3-allyl)-
(CO)2} complexes with aquo and hydroxo ligands are
summarized in what follows.
Mo) amounts of MeCN to these solutions yielded in-
stantaneously the compound [Mo(η3-C3H4-Me-2)(NCMe)-
(CO)2(phen)]BAr′4 (see Experimental Section), confirm-
ing the high lability of the aquo ligand.
Recrystallization from Et2O/hexane afforded single
crystals of 1, one of which was used for an X-ray
diffraction analysis. The crystal was found to be ther-
mally unstable due to loss of solvent; as a result, the
quality of the data is limited. The results of the
structure determination are displayed in Figure 1. The
cation of 1 consists of a {Mo(η3-C3H4-Me-2)(CO)2-
(phen)}+ moiety with a geometry resembling that found
in related neutral complexes,12 with a water molecule
coordinated trans to the allyl group (Figure 1a). The
coordinated water molecule makes two strong hydrogen
bonds with two molecules of diethyl ether, as indicated
by the distances O(3)-O(90) ) 2.603(8) Å and O(3)-
O(95) ) 2.707(9) Å (Figure 1b).
Resu lts a n d Discu ssion
As previously reported, the reaction of [Mo(η3-C3H5)-
(OTf)(CO)2(phen)] with NaBAr′4 (Ar′ ) 3,5-bis(trifluo-
romethyl)phenyl)9 in CH2Cl2 leads (through abstraction
of triflate as NaOTf, insoluble in CH2Cl2) to solutions
of cationic species that could include [Mo(η3-C3H5)(OH2)-
(CO)2(phen)]BAr′4.7 Repeated attempts to isolate crys-
talline solids from these solutions were unsuccessful.
However, we were pleased to find that upon addition of
water (3 equiv) to solutions obtained similarly from the
methallyl complex [Mo(η3-C3H4-Me-2)Cl(CO)2(phen)],10
red crystals of [Mo(η3-C3H4-Me-2)(OH2)(CO)2(phen)]-
BAr′4‚2Et2O (1) could be obtained (see Scheme 1) upon
crystallization from Et2O/hexane mixtures.11 The IR of
a CH2Cl2 solution of these crystals was identical to that
Treatment of THF solutions of 1 with strong bases
(BuLi or K[N(SiMe3)2]) led to IR νCO values considerably
lower than those of 1, suggesting deprotonation to give
a neutral hydroxo complex. A simple method to prepare
this complex was sought. The reaction of [Mo(η3-C3H4-
Me-2)Cl(CO)2(phen)] with KOH in a biphasic CH2Cl2/
H2O system afforded the targeted hydroxo complex
(Scheme 1), isolated as the hemihydrate [{Mo(η3-C3H4-
Me-2)(OH)(CO)2(phen)}2(µ-H2O)] (2), the structure of
which was determinated by single-crystal X-ray diffrac-
tion (Figure 2). Its IR was identical to that obtained by
deprotonation of 1. The IR νCO wavenumber values of 2
are close to those of related alkoxides [Mo(η3-C3H5)(OR)-
(CO)2(phen)].2 A difference between both types of com-
pounds is the high solubility of 2 in Et2O, due to
hydrogen bond interactions (the methoxo complex [Mo-
(η3-C3H5)(OMe)(CO)2(phen)] has a very small solubility
in Et2O). The presence of the hydroxo ligand is shown
1
of the mother solutions. H NMR examination of CD2-
Cl2 solutions obtained from the crystals showed a
multitude of signals that could not be assigned, in
agreement with extreme lability of the water ligand.
When excess water was added to the NMR tube, a single
species could be observed, corresponding to the aquo
complex 1. The addition of equimolar (with respect to
by the medium-intensity IR absorption at 3628 cm-1
,
(7) Morales, D.; Pe´rez, J .; Riera, L.; Riera, V.; Corzo-Sua´rez, R.;
Garc´ıa-Granda, S.; Miguel, D. Organometallics 2002, 21, 1540.
(8) Brisdon, B. J .; Cartwright, M.; Hodson, A. G. J . Organomet.
Chem. 1984, 277, 85.
(9) Brookhart, M.; Grant, B.; Volpe, A. F. Organometallics 1992, 11,
3920.
(10) Powell, P. J . Organomet. Chem. 1977, 129, 175.
(11) Note that while starting from the more labile triflato complex
was necessary for the generation of cationic complexes of the η3-C3H5
derivative, when the more electron-rich methallyl complex was used,
chloride abstration with NaBAr′4 was possible, saving the preparation
of the triflato complex.
and a broad signal at 1.61 ppm is assigned to exchange-
averaged hydroxo ligand and free water. The first
coordination sphere in 2 is similar to that found in the
complex [Mo(η3-C3H5)(OMe)(CO)2(phen)].2 As it is shown
in Figure 2, the unligated water molecule centered at
(12) Pe´rez, J .; Riera, L.; Riera, V.; Garc´ıa-Granda, S.; Garc´ıa-
Rodr´ıguez, E. Organometallics 2002, 21, 1622.

4936 Organometallics, Vol. 21, No. 23, 2002
Morales et al.
appreciably shorten this period. Thus, the long duration
of the reaction was attributed to its heterogeneous
nature. Accordingly, the synthesis of related alkoxo
complexes in homogeneous media is completed in min-
utes.2
Protonation of 2 with HOTf afforded [Mo(η3-C3H4-Me-
2)(OTf)(CO)2(phen)], pressumably via protonation of the
OH ligand followed by displacement of the resulting
aquo ligand by the triflate anion. On the other hand,
9
when the acid [H(Et2O)2]BAr′4 with less coordinating
anion was used, the protonation of 2 regenerated 1 (see
Experimental Section).
The reaction of equimolar amounts of 1 and 2 did not
lead to a simple mixture of 1 and 2 through H+ transfer;
rather, it afforded the binuclear cationic complex [{Mo-
(η3-C3H4-Me-2)(CO)2(phen)}2(µ-OH)]BAr′4 (3b) (Scheme
2) through water substitution by the nucleophilic hy-
droxo ligand. While this kind of reaction, termed ola-
tion,14 is believed to be common in condensation of acidic
aquo cations, no precedents involving isolated aquo and
hydroxo organometallic compounds are known to us.
The resulting cationic complex was isolated as BAr′4 salt
and characterized by spectroscopy and X-ray diffraction
(Figure 3) for the allyl derivative (3a ). The cation
consists of two identical {Mo(η3-C3H5)(CO)2(phen)} frag-
ments, similar to those present in 1 and 2, bridged by
a single OH ligand. Formation of 3b was also found to
occur upon addition of half the stoichiometric amount
of BuLi to THF solutions of 1. A search for an alterna-
tive synthesis starting from a simple precursor revealed
that complex 3a can be conveniently prepared by
reaction of [Mo(η3-C3H5)(OTf)(CO)2(phen)] with KOH in
anhydrous THF, as detailed in the Experimental Sec-
tion. A major difference between the synthetic routes
to the terminal 2 and bridged 3a ,b hydroxo complexes
is the presence of water in the former. We speculate
that, under these conditions, the chloride substitution
is effected by water rather than by hydroxide anion. The
resulting aquo complex would then be deprotonated in
the basic medium, yielding the terminal hydroxo com-
plex 2. Since the proton transfer is expected to be much
faster than the aquation step, significant concentrations
of the aquo complex would not build up, explaining why
it was not detected in the IR monitoring of the reaction.
On the other hand, working in water-free THF, hydrox-
ide would substitute the chloride ligand. The resulting
neutral hydroxo complex is highly soluble in THF, and
as its concentration grows, it becomes competitive with
free hydroxide ion (whose concentration in THF is low)
as a nucleophile (through the nondissociated OH ligand)
toward the remaining chloro complex, yielding the
observed OH-bridged product.
F igu r e 1. (a) Thermal ellipsoid (30% probability) plot of
the {Mo(η3-C3H4-Me-2)(OH2)(CO)2(phen)}+ cation of 1 with
hydrogen atoms omitted for clarity. (b) Structure of a 1
unit. Selected bond lengths (Å) and angles (deg): Mo(1)-
O(3) 2.196(7), O(3)-O(90) 2.603(8), O(3)-O(95) 2.707(9);
O(90)-O(3)-O(95) 104.2(5).
F igu r e 2. Thermal ellipsoid (30% probability) plot of 2.
Selected bond lengths (Å): Mo(1)-O(3) 2.055(5), Mo(51)-
O(53) 2.065(5), O(3)-O(91) 2.736(9), O(91)-O(53) 2.835-
(8).
Although compounds with OH bridges between {Mo-
(η3-C3H5)(CO)2} fragments are known,4 3a ,b are the first
complexes with a hydroxo group as a single bridge
between two molybdenum fragments. The Mo-O-Mo
angle in 3a (145.3(4)°) is, as expected, larger than in
species with several OH bridges4b,e-f and similar to the
Mo-Cl-Mo angle (134.0(1)°) in [{Mo(η3-C3H5)(CO)2-
(bipy)}2(µ-Cl)]BF4.15 Further aspects of the reactivity of
complexes 1-3 are under investigation in this labora-
tory.
O(91) participates in two hydrogen bonds, making
contacts of 2.736(9) and 2.835(8) Å with the hydroxy
oxygen atoms O(3) and O(53), respectively, of two [Mo-
(η3-C3H4-Me-2)(OH)(CO)2(phen)] molecules, acting as
donor in both hydrogen bonds.13
The preparation of 2 takes 24 h at room temperature
with good stirring. Starting from the more labile triflato
complex [Mo(η3-C3H4-Me-2)(OTf)(CO)2(phen)]7 did not
(13) In this context, donor means the group that formally bears the
hydrogen atom.
(14) J olivet, J . P. Metal Oxide Chemistry and Synthesis. From
Solution to Solid State; Wiley: Chichester, 2000; p 53.

Organometallic {Mo(η3-allyl)(CO)2(phen)} Fragments
Organometallics, Vol. 21, No. 23, 2002 4937
Sch em e 2
mmol) was added to the red solution. After 30 min stirring,
the solution was filtered through diatomaceous earth. In vacuo
concentration to 2 mL followed by addition of hexane (15 mL)
while stirring afforded a red precipitate that was dried in
vacuo. The dry solid was dissolved in diethyl ether (5 mL),
and hexane (15 mL) was layered. Slow diffusion at -20 °C
gave red-orange crystals of 1. The crystals were found to be
stable at room temperature under nitrogen for several days.
However, decomposition, showed by darkening and a decrease
in the intensity of the reflections, was observed when a single
crystal was subjected to a structure determination by X-ray
diffraction. When an NMR sample was prepared by dissolving
these crystals in CD2Cl2, the spectrum showed broad, nonin-
formative signals. However, addition of water (5 µL) to the
sample led to a well-resolved spectrum given below. Yield: 0.05
g, 60%. Anal. Calcd for C58H49BF24MoN2O5: C, 49.17; H, 3.48;
N, 1.98. Found: C, 49.44; H, 3.54; N, 2.12. IR (CH2Cl2): 1959,
1879 (νCO). 1H NMR (CD2Cl2): 9.29 [dd (J H2,3 ) 4.8, J H2,4
1.6), 2H, H2,9], 8.58 [dd (J H4,3 ) 7.9 Hz, J H4,5 ) 1.2 Hz), 2H,
4,7], 7.98 [s, 2H, H5,6], 7.93 [dd, 2H, H3,8], 7.71 [m, 8H, Ho],
7.50 [m, 8H, Hp], 6.23 [s, 2H, H2O], 3.37 [q (J ) 7.09), 8H,
Et2O], 3.14 [s, 2H, Hs], 1.44 [s, 2H, Ha], 1.08 [t (J ) 6.9), 12H,
Et2O], 0.68 [s, 3H, η3-C3H4(CH3)-2].
)
F igu r e 3. Thermal ellipsoid (30% probability) plot of the
[{Mo(η3-C3H5)(CO)2(phen)}2(µ-OH)]+ cation of 3a with hy-
drogen atoms omitted for clarity.
H
Syn th esis of [{Mo(η3-C3H4-Me-2)(OH)(CO)2(p h en )}2(µ-
H2O)] (2). A solution of KOH (0.1 g, excess) in H2O (0.5 mL)
was added to a solution of [Mo(η3-C3H4-Me-2)Cl(CO)2(phen)]
(0.03 g, 0.07 mmol) in CH2Cl2 (10 mL). After stirring for 24 h,
the mixture was cooled to -78 °C and the organic phase was
separated from the ice formed using filtration through a
cannula tipped with filter paper. The filtered solution was
concentrated in vacuo evaporation to a volume of 5 mL, layered
with hexane, and placed at -30°C, affording red needles of 2,
one of which was used for the structure determination by X-ray
diffraction. Yield: 0.03 g, 90%. Anal. Calcd for C18H16MoN2O3‚
0.5H2O: C, 52.31; H, 4.14; N, 6.78. Found: C, 52.20; H, 4.40;
N, 7.11. IR (THF): 1929, 1843 (νCO); (KBr): 3628 (νOH). 1H
NMR (CD2Cl2): 9.11 [dd (J H2,3 ) 5.1, J H2,4 ) 1.6), 4H, H2,9],
8.46 [dd (J H4,3 ) 8.2 Hz, J H4,5 ) 1.6 Hz), 4H, H4,7], 7.93 [s, 4H,
Exp er im en ta l Section
Gen er a l P r oced u r es. All manipulations were carried out
under nitrogen using standard Schlenk techniques. Solvents
were distilled from Na (hexane), Na/benzophenone (tetrahy-
drofuran), and CaH2 (CH2Cl2). CD2Cl2 was dried over molec-
ular sieves (4 Å) and stored over Na2CO3 in Young tubes in
the dark. Elemental analyses were obtained using a Perkin-
Elmer 240-B microanalyzer. The IR and NMR spectra were
recorded on Perkin-Elmer FT 1720-X (over the range 2200-
1600 cm-1) and Bruker AC-200 (or AC-300) spectrometers,
respectively, using TMS as internal reference for the NMR
spectra. [MoCl(η3-C3H4-(CH3)-2)(CO)2(phen)]10 was prepared
according to literature procedures.
Atom labelings for the allyl, phenanthroline, and BAr′4
groups are given in Scheme 3.
H
5,6], 7.80 [dd, 4H, H3,8], 2.98 [s, 4H, Hs], 1.61 [s br, 4H, H2O
Cr ysta l Str u ctu r e Deter m in a tion for Com p ou n d s 1, 2,
a n d 3a . Gen er a l Descr ip tion . The crystals of 1, 2, and 3a
were measured on a Bruker AXS SMART 1000 diffractometer.
Raw frame data were integrated with the SAINT16 program.
The structure was solved by direct methods with SHELXTL.17
All non-hydrogen atoms were refined anisotropically. All
calculations and graphics were made with SHELXTL.
Syn th esis of [Mo(η3-C3H4-Me-2)(OH2)(CO)2(ph en )]BAr ′4‚
2Et2O (1). CH2Cl2 (15 mL) was added to a mixture of [Mo(η3-
and OH], 1.27 [s, 4H, Ha], 0.84 [s, 6H, η3-C3H4(CH3)-2].
Syn th esis of [{Mo(η3-C3H5)(CO)2(p h en )}2(µ-OH)]BAr ′4
(3a ). KOH (0.1 g, excess) was added to a solution of [Mo(η3-
C3H5)(OTf)(CO)2(phen)]7 (0.10 g, 0.19 mmol) in THF (20 mL),
and the mixture was stirred for 20 h. The garnet solution was
filtered through paper-tipped cannula to eliminate the excess
of KOH and evaporated in vacuo. The residue was dissolved
in CH2Cl2 (10 mL), and NaBAr′4 (0.17 g, 0.19 mmol) was added,
causing the precipitation of a white solid. After stirring for 15
min the mixture was filtered through diatomaceous earth, and
the solution was concentrated in vacuo and precipitated with
hexane, affording a red microcrystalline solid, which was dried
in vacuo. Yield: 0.11 g, 73%. Single crystals suitable for an
X-ray diffraction analysis were obtained by slow diffusion of
hexane into a concentrated solution of 3a in CH2Cl2 at -20
°C. Anal. Calcd for C66H39BF24Mo2N4O5: C, 48.73; H, 2.42; N,
3.44. Found: C, 48.98; H, 2.40; N, 3.49. IR (CH2Cl2): 1964,
9
C3H4-Me-2)Cl(CO)2(phen)] (0.03 g, 0.07 mmol) and NaBAr′4
(0.06 g, 0.07 mmol). After 15 min stirring, water (4 µL, 0.22
(15) Curtis, M. D.; Fotinos, N. A.J . Organomet. Chem. 1984, 272,
43.
(16) SAINT+, SAX area detector integration program, Version 6.02;
Bruker AXS, Inc.: Madison, WI, 1999.
(17) Sheldrick, G. M. SHELXTL, An integrated system for solving,
refining, and displaying crystal structures from diffraction data,
Version 5.1; Bruker AXS, Inc.: Madison, WI, 1998.

4938 Organometallics, Vol. 21, No. 23, 2002
Ta ble 1. Cr ysta l Da ta a n d Refin em en t Deta ils for Com p lexes 1, 2, a n d 3b
Morales et al.
1
2
3b
formula
fw
cryst syst
space group
a, Å
C
58H47BF24MoN2O5
C18H17MoN2O3.50
413.28
triclinic
C66H38BF24Mo2N4O7
1657.69
tetragonal
P4hc2
18.0819(6)
18.0819(6)
21.5706(10)
90
90
90
7052(5)
4
1414.73
monoclinic
P2(1)/n
13.035(2)
13.655(3)
36.631(7)
90
99.132(4)
90
6438(2)
4
P1h
11.125(7)
12.985(8)
13.782(9)
106.383(12)
110.452(12)
99.849(12)
1707.4(19)
4
b, Å
c, Å
R, deg
â, deg
γ, deg
V, Å3
Z
T, K
293(2)
1.460
2848
299(2)
1.608
836
293(2)
1.561
3292
Dc, g cm-3
F(000)
λ(Mo KR), Å
cryst size, mm
µ, mm-1
scan range, deg
abs corr
no. of reflns measd
no. of ind reflns
no. of data/restraints/params
goodness-of-fit on F2
R1/Rw2 [I>2σ(I)]
R1/Rw2 (all data)
0.71073
0.14 × 0.15 × 0.20
0.319
1.13 e θ e 23.28
SADABS
28 177
9264
9264/0/825
0.983
0.71073
0.71073
0.10 × 0.10 × 0.10
0.473
1.13 e θ e 23.26
SADABS
31 382
5073
5073/0/475
1.019
0.02 × 0.06 × 0.31
0.790
1.70 e θ e 23.40
SADABS
7675
4925
4925/0/449
0.947
0.0944/0.2168
0.1972/0.2682
0.0518/0.0704
0.1068/0.0789
0.0588/0.1321
0.0997/0.1557
0.12 mmol). MeCN (0.5 mL) was added to the red solution.
After 10 min stirring, the solution was filtered through
diatomaceous earth, concentrated in vacuo to 2 mL, layered
with hexane (15 mL), and placed at -20 °C, affording orange
Sch em e 3
crystals. Yield: 0.105 g, 70%. Anal. Calcd for C52H30BF24
-
MoN3O2: C, 48.36; H, 2.34; N, 3.25. Found: C, 48.57; H, 2.52;
N, 3.39. IR(CH2Cl2): 1965, 1885 (νCO). 1H NMR (CDCl3): 9.15
[dd (J H2,3 ) 5.1, J H2,4 ) 1.6), 2H, H2,9], 8.38 [dd (J H4,3 ) 8.2 Hz,
J H4,5 ) 1.6 Hz), 2H, H4,7], 7.82 [dd, 2H, H3,8], 7.75 [s, 2H, H5,6],
7.71 [m, 8H, Ho], 7.50 [m, 8H, Hp], 3.24 [s, 2H, Hs], 1.89 [s,
3H, CH3CN], 1.74 [s, 2H, Ha], 1.29 [s, 3H, η3-C3H4(CH3)-2].
P r oton a tion of 2 w ith [H(Et2O)2]BAr ′4. A mixture of 2
(0.02 g, 0.05 mmol) and [H(Et2O)2]BAr′4 (0.05 g, 0.05 mmol)
was charged in a 5 mm NMR tube in the drybox. The tube
was stoppered with a rubber septum and taken out of the box.
CD2Cl2 (0.5 mL) was injected, causing the immediate dissolu-
1946, 1879, 1869 (νCO). 1H NMR (CD2Cl2): 8.88 [dd (J H2,3
)
5.0 Hz, J H2,4 ) 1.5), 4H, H2,9], 8.21 [dd (J H4,3 ) 8.2), 4H, H4,7],
7.75 [m, 8H, H-Co], 7.66 [s, 4H, H5,6], 7.57 [m, 8H, 4H-Cp and
4H of phen H3,8], 3.14 [d (J Hs,c ) 6.5), 4H, Hs], 2.78 [m, 2H,
Hc], 1.33 [d (J Ha,c ) 9.3), 4H, Ha], -2.47 [s, 1H, OH]. 3a is also
obtained by reaction of the aquo complex 1 with half the
1
tion of the solids. A H NMR spectrum showed the formation
of compound 1. Unlike when crystals of 1 are dissolved in CD2-
n
stoichiometric amount of BuLi in THF, as evidenced by the
1
Cl2 (see text) in the H NMR spectrum obtained as described
spectra of the resulting crude product. However, this method
was not further studied.
above, the signals of compound 1 can be clearly observed. We
attribute this difference to the presence of some adventitious
water in the extremely hygroscopic [H(Et2O)2]BAr′4 compound.
3
Syn th esis of [{Mo(η -C3H4-Me-2)(CO)2(p h en )}2(µ-OH)]-
BAr ′4 (3b). This compound can be prepared as described for
3a . The following method is an alternative. CH2Cl2 (10 mL)
was added to a mixture of 1 (0.05 g, 0.035 mmol) and 2 (0.02
g, 0.035 mmol), and the brown solution was stirred for 5 min,
concentrated in vacuo to a volume of 2 mL, layered with
hexane, and placed at -30 °C, affording brown-orange crystals,
which were dried in vacuo. Yield: 0.05 g, 86%. Anal. Calcd
for C68H43BF24Mo2N4O5: C, 49.35; H, 2.62; N, 3.38. Found: C,
49.52; H, 2.58; N, 3.41. IR (CH2Cl2): 1962 (sh), 1951, 1878 (sh),
1868 (νCO); KBr: 3700 (νOH). 1H NMR (CD2Cl2): 8.86 [dd (J H2,3
Ack n ow led gm en t. We thank Ministerio de Ciencia
y Tecnolog´ıa (Projects MCT-00-BQU2000-0220, PB97-
0470-C02-01) and Principado de Asturias (PR-01-GE-
7) for support, and predoctoral (L.R.) and postdoctoral
(D.M.) scholarships. M.E.N.C. thanks PCI-AL.E-2002,
AECI (Spain), and IPN (Mexico) for a visiting profes-
sorship.
) 4.9, J H2,4 ) 1.5), 4H, H2,9], 8.21 [dd (J H4,3 ) 8.2 Hz, J H4,5
)
Su p p or tin g In for m a tion Ava ila ble: General description
of crystal structure determination for compounds 1, 2, and 3a .
Tables giving positional and thermal parameters and bond
distances and bond angles for 1, 2, and 3a . This material is
available free of charge via the Internet at http://pubs.acs.org.
1.5 Hz), 4H, H4,7], 7.76 [m, 8H, Ho], 7.65 [s, 4H, H5,6], 7.59 [dd,
4H, H3,8], 7.55 [m, 8H, Hp], 2.95 [s, 4H, Hs], 1.32 [s, 4H, Ha],
0.53 [s, 6H, η3-C3H4(CH3)-2], -2.62 [s br, 1H, OH].
Syn th esis of [Mo(η3-C3H4-Me-2)(NCMe)(CO)2(p h en )]-
BAr ′4. CH2Cl2 (15 mL) was added to a mixture of [Mo(η3-C3H4-
Me-2)Cl(CO)2(phen)] (0.05 g, 0.12 mmol) and NaBAr′4 (0.10 g,
OM0203882