Reactivity of [MCl(η3-allyl)(CO)2(N-N)] complexes (M = Mo, W; N-N = bipy, phen) toward alkyl and acetylide anions

Article abstract of DOI:10.1021/om0107800

The reactions of [MoCl(η³-allyl)(CO)₂(N-N)] (N-N = bipy, phen) and of the related tungsten complexes with MgR₂ reagents (R = Me, Et, Bz) were discussed. These reactions gave as single products the new alkyls [M(R)(η^3<

Full text of DOI:10.1021/om0107800

1622
Organometallics 2002, 21, 1622-1626
Rea ctivity of [MCl(η3-a llyl)(CO)2(N-N)] Com p lexes (M )
Mo, W; N-N ) bip y, p h en ) tow a r d Alk yl a n d Acetylid e
An ion s
J ulio Pe´rez,*,† Luc´ıa Riera,† V´ıctor Riera,† Santiago Garc´ıa-Granda,‡ and
Esther Garc´ıa-Rodr´ıguez‡
Departamento de Quı´mica Orga´nica e Inorga´nica/ IUQOEM, and Departamento de Quı´mica
Fı´sica y Anal´ıtica, Facultad de Quı´mica, 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 August 27, 2001
The reactions of [MoCl(η3-allyl)(CO)2(N-N)] (N-N ) bipy, phen) and of the related
tungsten complexes with MgR2 reagents (R ) Me, Et, Bz) gave as single products the new
alkyls [M(R)(η3-allyl)(CO)2(N-N)] (3-9), which have the alkyl and allyl groups in trans
positions. Related alkynyls [M(CtCR)(η3-allyl)(CO)2(N-N)] with R ) Ph, SiMe3, H (10-15)
were obtained similarly employing alkaline acetylides.
In tr od u ction
migration with concomitant reductive elimination of the
resulting olefin would complete the cycle.7
In Trost’s seminal paper [MoX(η3-allyl)(CO)2(L-L)]
complexes were reported to react with stabilized carb-
anions to afford olefins.6a However, the reactivity of
these complexes toward nonstabilized carbanions re-
mains unexplored.8 This work reports our studies in this
area.9
Despite the extensive research carried out on the
organometallic chemistry of Mo(II) and W(II) halocar-
bonyl complexes,1 alkyl and alkynyl derivatives are
nearly limited to fragments containing cyclopentadienyl
ligands.2
The metathesis between a halocomplex and a main
group organometallic such as an organolithium or
organomagnesium reagent is often used to create new
metal-carbon bonds.3 However, this route can be
hampered by the presence of ligands able to (a) act as
alternative sites of the nucleophilic attack or (b) undergo
intramolecular migration of an initially formed alkyl
ligand. The presence of the carbonyl ligand itself can
bring about this problem. Thus, Carmona found that
η2-acyls are the only products of the reaction between
halocarbonyl Mo(II) phosphine complexes with carban-
ionic reagents, presumably via the intermediacy of alkyl
carbonyl complexes.4
For [MoX(η3-allyl)(CO)2(L-L)] (X ) anionic ligand,
L-L ) neutral chelate) compounds, the allyl group is a
potential target of the alkylation,5 and this reaction has
an added interest since molybdenum carbonyl com-
plexes catalyze the alkylation of allylic electrophiles.6
This is believed to occur by oxidative addition to an
electron-rich zerovalent species to give a Mo(II) η3-allyl
complex. Subsequent alkylation either directly to the
allyl or to the metal followed by an alkyl-to-allyl
Resu lts a n d Discu ssion
The reaction of [MoCl(η3-C3H5)(CO)2(bipy)]10 (1a ) with
MgMe2 in THF afforded the methyl complex [Mo(CH3)-
(η3-C3H5)(CO)2(bipy)] (3a ). Its spectroscopic data include
two similarly intense bands at wavenumbers lower than
in 1a , indicating the persistence of a cis-Mo(CO)2 unit,
(5) The stoichiometric nucleophilic addition to η3 ligands in molyb-
denum complexes was studied for η5-cyclopentadienyl or hydrotris-
(pyrazolyl)borate ligands. See, for instance: (a) VanArsdale, W. E.;
Winter, R. E. K.; Kochi, J . K. Organometallics 1986, 5, 645. (b) Faller,
J . W.; Linebarrier, D. Organometallics 1988, 7, 1670. (c) Ward, Y. D.;
Villanueva, L. A.; Allred, G. D.; Payne, S. C.; Semones, M. A.;
Liebeskind, L. S. Organometallics 1994, 13, 1476.
(6) (a) Trost, B. M.; Lautens, M. J . Am. Chem. Soc. 1982, 104, 5543.
(b) Trost, B. M.; Merlic, C. A. J . Am. Chem. Soc. 1990, 112, 9590. (c)
Trost, B. M.; Hachiya, I. J . Am. Chem. Soc. 1998, 120, 1104.
(7) Sjo¨gren, M. P. T.; Frisell, H.; Akermark, B.; Norrby, P. O.;
Eriksson, L.; Vitagliano, A. Organometallics 1997, 16, 942.
(8) The only such reaction reported is that of [MoX(η3-C3H5)(CO)2-
(DAB)] (X ) Cl, Br; DAB ) N,N′-dialkylethanediimine) with MeLi or
MeMgI, which afforded unidentified decomposition products: Hsieh,
A. T. T.; West, B. O. J . Organomet. Chem. 1976, 112, 285. The
possibility of nucleophilic attack to the metal was suggested: Curtis,
M. D.; Fotinos, N. A. J . Organomet. Chem. 1984, 272, 43. Trost found
results suggesting attack to the metal by the less bulky malonate
anions: Trost, B. M.; Lautens, M. J . Am. Chem. Soc. 1987, 109, 1469.
For another example of at-the-metal attack by a soft nucleophile, see:
Faller, J . W.; Linebarrier, D. Organometallics 1988, 7, 1670.
(9) Part of this work has been previously communicated: Pe´rez, J .;
Riera, L.; Riera, V.; Garc´ıa-Granda, S.; Garc´ıa-Rodr´ıguez, E. J . Am.
Chem. Soc. 2001, 123, 7469.
* Corresponding author. E-mail: japm@sauron.quimica.uniovi.es.
† Departamento de Qu´ımica Orga´nica e Inorga´nica/IUQOEM.
‡ Departamento de Qu´ımica F´ısica y Anal´ıtica.
(1) Baker, P. K. Adv. Organomet. Chem. 1995, 40, 45.
(2) (a) Nast, R. Coord. Chem. Rev. 1982, 47, 89. (b) Manna, J .; J ohn,
K. D.; Hopkins, M. D. Adv. Organomet. Chem. 1995, 38, 79.
(3) Crabtree, R. H. The Organometallic Chemistry of the Transition
Metals, 2nd Ed.; J ohn Wiley & Sons: New York, 1994; p 50.
(4) Carmona, E.; Sa´nchez, L.; Mar´ın, J . M.; Poveda, M. L.; Atwood,
J . L.; Priester, R. D.; Rogers, R. D. J . Am. Chem. Soc. 1984, 106, 3214.
(10) (a) Hull, C. G.; Stiddard, M. H. B. J . Organomet. Chem. 1967,
9, 519. (b) tom Dieck, H.; Friedel, H. J . Organomet. Chem. 1968, 14,
375. (c) Brisdon, B. J . J . Organomet. Chem. 1977, 125, 225.
10.1021/om0107800 CCC: $22.00 © 2002 American Chemical Society
Publication on Web 03/16/2002

[MCl(η3-allyl)(CO)2(N-N)] Complexes
Organometallics, Vol. 21, No. 8, 2002 1623
Sch em e 1
The new alkyls can be handled in the air for short
periods of time without noticeable decomposition, are
stable in nonchlorinated solvents, and are moderately
sensitive toward air and moisture. Their reflux in THF
(6 h) did not cause elimination of alkyl-allyl coupling
products, probably reflecting a configurational stability
that keeps the hydrocarbyl ligands on distant sites of
the molecule. The stability of the ethyl complexes
toward â-elimination can be attributed to the lack of
facile dissociation processes in these electron-precise
compounds.13 As a result of this saturation, the new
alkyls do not react with nucleophiles.14 Thus, treatment
with carbon monoxide (bubbling for 1 h at room tem-
perature) or trimethylphosphine (5 equiv, 70 h at room
temperature) does not induce alkyl migration to the
proximate CO ligands. The same reason can explain the
inertness of the new alkyls toward unsaturated organic
electrophiles such as p-tolyl isocyanate and carbon
disulfide, which typically insert into metal-carbon
bonds,15 since insertion usually requires previous coor-
dination of the unsaturated molecule. The new alkyls
do not react with weak acids such as methanol or
phenylacetylene (5 equiv, 20 h in acetone-d6 solution
at room temperature). Triflic acid or benzenethiol
selectively protonates the alkyl-molybdenum bond,
yielding [Mo(X)(η3-allyl)(CO)2(N-N)] (X ) OTf, SPh)
complexes and the alkane. This selectivity is remark-
able, since the allyl protonation of Mo(η3-allyl) com-
plexes has been used to generate a vacant coordination
site.16
Sch em e 2
The alkyl complexes underwent a transformation to
their chloroprecursors in chlorinated solvents. Our
attempts to grow single crystals of the new alkyls from
toluene, THF, or acetone solutions failed. Dark green
single crystals could be grown by slow diffusion of
hexane into concentrated solutions of the methyl com-
plexes 3a and 3b in CH2Cl2, but they were found to
consist of Mo-CH3 and Mo-Cl mixtures.17-19
a low-frequency 1H NMR singlet, typical of a metal-
bound methyl group, and a pattern of two doublets and
one multiplet in H NMR, diagnostic of a static (without
1
fast equilibration to η1) η3-C3H5 group like the one
present in 1a . The set of four multiplets for the bipy
hydrogens, together with the equivalence of the two syn
hydrogens and of the two anti hydrogens, maintained
when the temperature was lowered to 190 K,11 is
consistent with the existence of a mirror plane, and
therefore, the structure depicted in Scheme 1 can be
assigned to 3a .
We found that [Mo(CH3)(η3-methallyl)(CO)2(phen)]
(9), prepared as described for 3a , crystallized free from
the chlorinated companion. An X-ray diffraction deter-
mination (Figure 1 and Table 1) showed 9 to be
isostructural with 3a , 3b, and known [MoX(η3-allyl)-
(CO)2(N-N)] complexes,1 having the alkyl and allyl
groups on opposite sides of the equatorial plane defined
by the two carbonyls and the two nitrogen atoms, and
the allyl oriented with the wingtip carbons pointing
toward the carbonyls,20 resulting in Cs symmetry.
Related ethyl (4a ) and benzyl (5a ) derivatives, as well
as the three analogues with N-N ) phen (compounds
3b, 4b, and 5b), and the methyl (6), ethyl (7), and benzyl
(8) tungsten phen complexes were prepared.
These alkylations took place selectively at the metal,
and neither acyl complexes nor allylic alkylation prod-
ucts were formed.
(12) For tungsten alkyls see: (a) Carmona, E.; Contreras, L.; Poveda,
M. L.; Sa´nchez, L. J .; Atwood, J . L.; Rogers, R. D. Organometallics
1991, 10, 61. (b) Carmona, E.; Contreras, L.; Gutie´rrez-Puebla, E.;
Monge, A.; Sa´nchez, L. Organometallics 1991, 10, 71.
(13) Eagle, A. A.; Young, C. G.; Tiekink, E. R. T. Organometallics
1992, 11, 2934.
The higher solubility of the phen complexes allowed
their 13C NMR spectra to be acquired. The spectra of
the new complexes indicate a structure like that of 3a .
These compounds are the first [Mo(R)(η3-allyl)(CO)2L2]
derivatives and add to the very few examples of alkyl
carbonyl molybdenum and tungsten complexes without
cyclopentadienyl ligands.12 The lower νCO values for the
tungsten complexes reflect the more electron-rich nature
of the third-row metal.12a
(14) Reactivity of [MoCl(η3-allyl)(CO)2(NCMe)2] with excess trial-
kylphosphines is known to cause reductive elimination to yield Mo(0)
complexes: Clark, D. A.; J ones, D. L.; Mawby, R. J . J . Chem. Soc.,
Dalton Trans. 1998, 565.
(15) (a) Braunstein, P.; Nobel, D. Chem. Rev. 1989, 89, 1927. (b)
Legzdins, P.; Rettig, S. J .; Ross, K. J . Organometallics 1994, 13, 569.
(16) (a) Markham, J .; Menard, K.; Cutler, A. Inorg. Chem. 1985,
24, 1581-1587. (b) Calhorda, M. J .; Gamelas, C. A.; Gonc¸alves, I. S.;
Herdtweck, E.; Roma˜o, C. C.; Veiros, L. F. Organometallics 1998, 17,
2597-2611, and references therein.
(17) For an example of a mixture of isostructural Mo-Cl and Mo-
CH3 complexes in single crystals, see: Cotton, F. A.; Wiesinger, K.
Inorg. Chem. 1990, 29, 2594.
(11) In complexes [MoX(η3-allyl)(CO)2(P-P)] (X ) halide, P-P )
bidentate phosphine), a dynamic process fast at room temperature in
the NMR time scale lends an apparent Cs symmetry to the molecule.
However, the low-temperature NMR spectra indicate that one P is
trans to a CO ligand and the other P is trans to the allyl, a geometry
also found in the solid-state structure: Faller, J . W.; Haitko, D. A.;
Adams, R. D.; Chodosh, D. F. J . Am. Chem. Soc. 1979, 101, 865.
(18) See Supporting Information for details.
(19) For X-ray analyses of compositionally disordered crystals, see:
Parkin, G. Adv. Inorg. Chem. 1995, 42, 291.

1624 Organometallics, Vol. 21, No. 8, 2002
Pe´rez et al.
F igu r e 1. Molecular structure and numbering scheme of
9. Selected bond lengths (Å) and angles (deg): Mo(1)-C(1)
2.339(3); C(2)-Mo(1)-C(1) 88.31(11), C(3)-Mo(1)-C(1)
87.87(9); N(1)-Mo(1)-C(1) 79.18(9); N(2)-Mo(1)-C(1)
75.95(8).
Ta ble 1. Cr ysta l Da ta a n d Refin em en t Deta ils for
Com p lexes 9 a n d 10
F igu r e 2. Molecular structure and numbering scheme of
10. Selected bond lengths (Å) and angles (deg): Mo-C(3)
2.16(2); C(4)-C(41) 1.49(3); C(3)-C(4) 1.20(3); Mo-C(3)-
C(4) 169.6(19); C(3)-C(4)-C(41) 174(2).
9
10
formula
C
19H18MoN2O2
C23H18MoN2O2‚
1/2CH2Cl2
492.80
triclinic
P1
8.673(2)
10.337(2)
12.355(3)
96.58(2)
98.95(2)
100.32(2)
1064.8(4)
2
fw
402.29
monoclinic
P21/c
8.8017(4)
13.2357(6)
15.1162(7)
90
99.669(1)
90
1735.97(14)
4
The reaction of 1a with lithium phenylacetylide
afforded the alkynyl complex [Mo(CtCPh)(η3-allyl)-
(CO)2(bipy)] (10) as the only product. Its IR spectrum
displayed two strong νCO bands and a weak band at 2077
cm-1 assigned to the acetylenic C-C stretching.2,23 The
1H NMR spectrum 10 shows, in addition to the phenyl
multiplets, sets of bipy and allyl signals such as those
found for the alkyl compounds 3-5, indicating a similar
geometry. The limited solubility of 10 precluded the
observation of the acetylenic carbons in the 13C NMR
spectrum (see Experimental Section). The structure of
10 was determined by X-ray diffraction (see Figure 2
and Table 1).
cry syst
space group
a, Å
b, Å
c, Å
R, deg
â, deg
γ, deg
V, Å3
Z
T, K
293(2)
1.539
816
293(2)
1.537
498
Dc, g cm-3
F(000)
λ(Mo KR), Å
cryst size, mm
µ, mm-1
scan range, deg
no of reflns measd
no of ind reflns
0.71073
0.71073
0.24 × 0.15 × 0.11 0.23 × 0.17 × 0.10
0.768
0.763
1.69 e θ e 25.97
4379
The results confirm the geometry inferred from
spectroscopic data. In particular, the distance between
the two acetylenic carbons (1.20(3) Å) and the alignment
of those atoms, the ipso carbon, and the molybdenum
atom (Mo-C(3)-C(4) ) 170(2)°, C(3)-C(4)-C(41) )
174(2)°) are typical of alkynyl complexes.2b,24
2.06 e θ e 23.24
10 810
2492
4379
no. of data/restraints/ 2492/0/220
params
4379/3/635
goodness-of-fit on F2
R1/Rw2 [I > 2σ(I)]
R1/Rw2 (all data)
1.007
0.0222/0.0641
0.0239/0.0656
1.033
0.0370/0.0853
0.0788/0.1010
(22) Most Mo-Calkyl bond lengths are within the range 2.131-2.264
Å: Schrauzer, G. N.; Hughes, L. A.; Strampach, N.; Robinson, P. R.;
Schlemper, E. O. Organometallics 1982, 1, 44. For a very recent paper
containing structural data of several molybdenum methyl complexes,
see: Sharp, W. B.; Daff, P. J .; McNeil, W. S.; Legzdins, P. J . Am. Chem.
Soc. 2001, 123, 6272. For Mo-CH3 distances longer than the one found
in 9, see: (a) Sharp, W. B.; Daff, P. J .; McNeil, W. S.; Legzdins, P. J .
Am. Chem. Soc. 2001, 123, 6272. (b) Churchill, M. R. Perspectives in
Coordination Chemistry; Dunitz, J ., Ibers, J . A., Eds.; Wiley: New
York, 1970; Vol. 3, p 91.
Unlike for 3a and 3b, the metrical data of 9 could be
determined with considerable accuracy.21 The Mo-
Cmethyl distance (2.339(3) Å) is one of the longer ones
found for mononuclear molybdenum methyl complexes.22
We wished to study the reactivity of [MoCl(η3-allyl)-
(CO)2(N-N)] complexes with other carbanions. We
wanted to know whether the softer character of acetyl-
ides would translate into a regiochemistry different from
that found for alkyl anions (see above). Otherwise,
acetylide attack to the metal would yield alkynyl
complexes. Molybdenum and tungsten alkynyls without
cyclopolyenyl ligands are rare.23
(23) Gamasa, M. P.; Gimeno, J .; Zhang, L.; Lanfranchi, M.; Tiri-
picchio, A. J . Organomet. Chem. 1996, 514, 287.
(24) For crystallographically characterized molybdenum complexes
having terminal alkynyl ligands, see ref 23 and: (a) Buang, N. A.;
Hughes, D. L.; Kashef, N.; Richards, R. L.; Pombeiro, A. J . L. J .
Organomet. Chem. 1987, 323, C47. (b) Beddoes, R. L.; Bitcon, C.;
Ricalton, A.; Whiteley, M. W. J . Organomet. Chem. 1989, 367, 85. (c)
Pombeiro, A. J . L.; Hills, A.; Hughes, D. L.; Richards, R. L. J .
Organomet. Chem. 1990, 398, C15. (d) Beddoes, R. L.; Bitcon, C.;
Whiteley, M. W. J . Organomet. Chem. 1991, 402, C85. (e) Hills, A.;
Hughes, D. L.; Kashef, N.; Lemos, M. A. N. D. A.; Pombeiro, A. J . L.;
Richards, R. L. J . Chem. Soc., Dalton Trans. 1992, 1775. (f) Stoner, T.
C.; Geib, S. J .; Hopkins, M. D. Angew. Chem., Int. Ed. Engl. 1993, 32,
409. (g) Stoner, T. C.; Schaefer, W. P.; Marsh, R. E.; Hopkins, M. D. J .
Cluster Sci. 1994, 5, 107. (h) J ohn, K. D.; Geib, S. J .; Hopkins, M. D.
Organometallics 1996, 15, 4357.
(20) Curtis, M. D.; Eisenstein, O. Organometallics 1984, 3, 887.
(21) However, we have to recognize that the presence of a low level
of the chloro complex as an impurity in the crystal of 9, which would
have resulted in an elongated apparent Mo-Cmethyl distance and would
have been compatible with normal thermal parameters and with high
precision, is difficult to rule out conclusively; see p 375 of ref 19. We
did not detect the presence of the chloro complex in our analytic or
spectroscopic data.

[MCl(η3-allyl)(CO)2(N-N)] Complexes
Organometallics, Vol. 21, No. 8, 2002 1625
The complex [Mo(CtCSiMe3)(η3-allyl)(CO)2(bipy)] (11)
was prepared in a similar way and characterized
spectroscopically. The acetylenic C-C IR stretching
stages of the refinement, all positional parameters and the
anisotropic temperature factors of all the non-H atoms were
refined using SHELXL97.32 The H atoms were isotropically
refined. Plots were made with the EUCLID package.34 Geo-
metrical calculations were made with PARST.35
appears as a weak band at 2075 cm-1 25
The signals of
.
the acetylenic carbons could be observed in 13C NMR
as low-intensity singlets at 161.82 and 117.60 ppm,
assigned to the Mo- and Si-bonded carbons, respectively,
by comparison with known complexes.26
Syn th esis of [W(CH3)(η3-C3H5)(CO)2(p h en )] (6). To a
solution of 236 (0.10 g, 0.20 mmol) in THF (20 mL) was added
MgMe2 (0.20 mmol, 0.7 mL of a 0.29 M solution in Et2O). The
color of the solution changed immediately from orange to blue.
After stirring for 15 min, the solvent was removed under
vacuum. The residue was redissolved in toluene and filtered
through Celite. Solvent evaporation afforded 0.064 g of 6 (67%)
The ethynyl derivative [Mo(CtCH)(η3-allyl)(CO)2-
(bipy)] (14a ) was synthesized by reaction of 1a with
excess sodium acetylide. In addition to the two νCO
bands at 1947 and 1855 cm-1, the IR of 14a shows an
absorption at 1933 cm-1, attributed to the acetylenic
C-C stretching. The ethynyl hydrogen occurs at 2.12
1
as a blue solid. IR (CH2Cl2): 1914, 1820 (νCO). H NMR (CD2-
Cl2): 9.08, 8.48, 8.01 and 7.75 [m, 2H each, phen], 2.70 [d (5.9),
2H, Hsyn], 2.04 [m, 1H, CH of η3-C3H5], 1.64 [d (8.3), 2H, Hanti],
-0.83 [s, 3H W-CH3]. 13C{1H} NMR (CD2Cl2): 227.97 [CO],
150.97, 144.66, 135.33, 130.22, 127.00 and 124.36 [phen], 65.84
[C2 of η3-C3H5], 43.30 [C1 and C3 of η3-C3H5], 14.90 [W-CH3].
Anal. Calcd for C18H16N2O2W: C, 62.08; H, 4.34; N, 6.06.
Found: C, 61.78; H, 4.29; N, 6.13.
Syn th esis of [W(CH 2CH3)(η3-C3H5)(CO)2(p h en )] (7). 7
was obtained from 2 (0.10 g, 0.20 mmol) and MgEt2 (1.14 mL
of a 0.21 M solution in Et2O, 0.24 mmol). Yield: 0.057 g, 65%
(dark blue solid). IR (CH2Cl2): 1917, 1826 (νCO). 1H NMR (CD2-
Cl2): 9.02, 8.44, 7.97 and 7.74 [m, 2H each, phen], 2.71 [d (6.2),
2H, Hsyn], 2.66 [m, 1H, CH of η3-C3H5], 1.47 [t (7.8), 3H,
W-CH2CH3], 1.35 [d (8.2), 2H, Hanti], -0.34 [q (7.8), 2H, Mo-
CH2CH3]. 13C{1H} NMR (CD2Cl2): 227.87 [CO], 150.92, 143.36,
136.34, 127.06, 124.97 and 124.01 [phen], 67.63 [C2 of η3-C3H5],
45.01 [C1 and C3 of η3-C3H5], 24.41 [Mo-CH2CH3], 14.17 [Mo-
CH2CH3]. Anal. Calcd for C19H18N2O2W: C, 46.55; H, 3.70; N,
5.71. Found: C, 46.48; H, 3.59; N, 5.81.
Syn th esis of [W(CH2C6H5)(η3-C3H5)(CO)2(p h en )] (8). 8
was obtained from 2 (0.10 g, 0.20 mmol) and MgBz2 (0.6 mL
of a 0.34 M solution in THF, 0.20 mmol). Yield of 8 as a dark
blue solid: 0.082 g, 74%. IR (CH2Cl2): 1917, 1827 (νCO). 1H
NMR (CD2Cl2): 8.96, 8.34, 7.85 and 7.65 [m, 2H each, phen],
6.26 [m, 3H, C6H5], 6.19 [m, 2H, C6H5], 2.72 [d (6.1), 2H, Hsyn],
1.95 [s, 2H, W-CH2C6H5], 1.87 [m, 1H, CH of η3-C3H5], 1.66
[d (8.4), 2H, Hanti]. 13C{1H} NMR (CD2Cl2): 226.82 [CO],
151.50, 142.31, 135.63, 130.61, 128.85, 128.69, 127.56, 126.26,
125.10 and 124.79 [phen and C6H5], 65.67 [C2 of η3-C3H5], 45.10
[C1 and C3 of η3-C3H5], 38.24 [W-CH2C6H5]. Anal. Calcd for
1
ppm in the H NMR, and the two acetylenic carbons as
weak signals at 100.61 and 79.92 ppm in the 13C NMR.
The complex [Mo(CtCH)(η3-allyl)(CO)2(phen)] (14b)
and the tungsten alkynyls [W(CtCPh)(η3-allyl)(CO)2-
(phen)] (12), [W(CtCSiMe3)(η3-allyl)(CO)2(phen)] (13),
and [W(CtCH)(η3-allyl)(CO)2(phen)] (15) were prepared
analogously and characterized spectroscopically (see
Experimental Section).
In each reaction, the alkynyl complex was found to
be the only product. The new alkynyls are, like the
alkyls 3-9, reluctant to eliminate C-C coupling prod-
ucts when heated for hours in THF.
Exp er im en ta l Section
General procedures were given elsewhere.9
X-r a y Cr ysta llogr a p h ic An a lyses. The crystal of 9 was
measured on a Bruker AXS SMART 1000 CCD diffractometer.
Raw frame data were integrated with the SAINT27 program.
The structure was solved by direct methods with SHELXTL.28
A semiempirical absorption correction was applied with SAD-
ABS.29 All non-hydrogen atoms were refined as riding atoms,
with a common thermal parameter. All calculations were made
with SHELXTL.
The crystal of 10 was measured on a Nonius CAD4 diffrac-
tometer. On all reflections, a profile analysis was performed.30
Symmetry-equivalent and other redundant reflections were
averaged and drift, Lorentz, and polarization corrections were
applied. The structure was solved by Patterson methods using
DIRDIF-96.31 Isotropic least-squares refinement on F2 was
performed using SHELXL97.32 An empirical absorption cor-
rection was applied at this stage, using XABS2.33 All the H
atoms were located by Fourier synthesis. During the final
C
24H20N2O2W: C, 52.19; H, 3.65; N, 5.07. Found: C, 51.93; H,
3.72; N, 5.05.
Syn th esis of [Mo(CH3)(η3-m eth a llyl)(CO)2(p h en )] (9).
9 was obtained from 1c37 (0.10 g, 0.24 mmol) and MgMe2 (0.9
mL of a 0.29 M solution in Et2O, 0.24 mmol). Slow diffusion
of hexane into a solution of 9 in THF (10 mL) at -20 °C
afforded dark blue crystals of 9, one of which was used for the
X-ray analysis. Yield: 0.080, 84%. IR (CH2Cl2): 1921, 1831
(νCO). 1H NMR (CD2Cl2): 8.91, 8.39, 7.97 and 7.71 [m, 2H each,
phen], 2.55 [s, 2H, Hsyn], 1.56 [s, 2H, Hanti], 0.59 [s, 3H, CH3 of
methallyl], -0.72 [s, 3H, Mo-CH3]. 13C{1H} NMR (CD2Cl2):
235.80 [CO], 151.24, 144.20, 135.48, 130.57, 127.48 and 124.16
[phen], 83.32 [C2 of methallyl], 53.48 [C1 and C3 of methallyl],
18.86 [CH3 of methallyl], 11.15. [Mo-CH3]. Anal. Calcd for
C19H18MoN2O2: C, 56.73; H, 4.51; N, 6.96. Found: C, 56.81;
H, 4.49; N, 6.73.
(25) IR data of trimethylsilylacetylide complexes have been collected
in the Supporting Information of: J ohn, K. D.; Hopkins, M. D.
Organometallics 1997, 16, 4948.
(26) 13C NMR signals corresponding to the molybdenum-bonded
acetylenic carbon of a trimethylsilylacetylide ligand have been found
to occur at relatively high frequencies. (a) See ref 23. (b) Lang, H.;
Blau, S.; Rheinwald, G.; Zsolnai, L. J . Organomet. Chem. 1995, 494,
65.
(27) SAINT + SAX area detector integration program, version 6.02;
Bruker AXS, Inc.: Madison, WI, 1999.
(28) 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, 1988.
Syn th esis of [Mo(CtCP h )(η3-C3H5)(CO)2(bip y)] (10). To
a solution of phenylacetylene (51 µL, 0.46 mmol) in THF (10
mL) cooled to 195 K was added nBuLi (0.35 mL of 1.6 M
solution in hexane, 0.56 mmol), and the resulting solution of
LiCtCPh was transferred via cannula into a solution of 1a
(0.10 g, 0.26 mmol) in THF (20 mL). The mixture was allowed
to reach room temperature and stirred for 45 min. The
(29) Sheldrick, G. M. SADABS, empirical absorption correction
program; University of Go¨ttingen: Go¨ttingen, Germany, 1997.
(30) (a) Lehman, M. S.; Larsen, F. K. Acta Crystallogr. 1974, A30,
580. (b) Grant, D. F.; Gabe, E. J . J . Appl. Crystallogr. 1978, 11, 114.
(31) Beurskens, P. T.; Admiraal, G.; Beurskens, G.; Bosman, W. P.;
Garc´ıa-Granda, S.; Gould, R. O.; Smits, J . M. M.; Smykalla, C. The
DIRDIF96 Program System; Technical Report of the Crystallography
Laboratory: University of Nijmegen, The Netherlands, 1996.
(32) Sheldrick, G. M. SHELXL-97, Program for the refinement of
crystal structures; University of Go¨ttingen: Germany, 1989.
(33) Parkin, S.; Moezzi, B.; Hope, H. J . Appl. Crystallogr. 1995, 28,
53.
(34) Spek, A. L. The EUCLID Package. In Computational Crystal-
lography; Sayre, D., Ed.; Clerendon Press: Oxford, 1982; p 528.
(35) Nardelli, M. Comput. Chem 1983, 7, 95.
(36) Brisdon, B. J .; Griffin, G. F. J . Chem. Soc., Dalton Trans. 1975,
1999.

1626 Organometallics, Vol. 21, No. 8, 2002
Pe´rez et al.
resulting dark red solution was evaporated in vacuo, and the
residue was extracted with CH2Cl2 (30 mL) and filtered
through diatomaceous earth. Pure 10 was obtained by slow
diffusion of hexane into a CH2Cl2 solution at 250 K. One of
the resulting dark red crystals was used for the X-ray
determination. Yield: 0.070 g, 67%. IR (CH2Cl2): 2077 (νCtC);
[C1 and C3 of η3-C3H5], 1.18 [W-CtCSi(CH3)3]. Anal. Calcd for
C
22H22N2O2SiW: C, 47.32; H, 3.97; N, 5.02. Found: C, 47.61;
H, 4.07; N, 4.96.
[Mo(CtCH)(η3-C3H5)(CO)2(bip y)] (14a ). To a suspension
of 0.30 g (large excess) of NaCtCH (previously washed with
hexane from the mineral oil accompanying the commercial
product) in THF was added a solution of [MoCl(η3-C3H5)(CO)2-
(bipy)] (1a ) (0.10 g, 0.26 mmol) in THF. The mixture was
stirred for 3 h, and then the volatiles were removed in vacuo.
The residue was extracted with CH2Cl2 (30 mL) and filtered
through diatomaceous earth, and the resulting solution was
concentrated by in vacuo evaporation to a volume of 10 mL.
Addition of hexane (30 mL) caused the precipitation of 14a as
a red microcrystalline solid, which was dried under reduced
pressure. Yield: 0.060 g, 66%. IR (CH2Cl2): 1933 (νCtC); 1947,
1855 (νCO). 1H NMR (CD2Cl2): 8.82, 8.14, 7.99 and 7.52 [m,
2H each, bipy], 3.19 [d (6.7), 2H, Hsyn], 3.06 [m, 1H, CH of η3-
C3H5], 2.12 [s, 1H, Mo-CtCH], 1.64 [d (9.6), 2H, Hanti]. 13C-
{1H} NMR (CD2Cl2): 228.79 [CO], 152.16, 137.23, 130.29,
127.47 and 124.83 [bipy], 100.61 [Mo-CtC], 79.92 [Mo-CtC],
77.06 [C2 of η3-C3H5], 56.45 [C1 and C3 of η3-C3H5]. Anal. Calcd
for C17H14MoN2O2: C, 54.56; H, 3.77; N, 7.48. Found: C, 54.49;
H, 3.81; N, 7.46. 14b and 15 were prepared analogously.
1
1939, 1852 (νCO). H NMR (CD2Cl2): 8.72, 8.01, 7.95 and 7.44
[m, 2H each, bipy], 6.97 [m, 3H, C6H5], 6.77 [m, 2H, C6H5],
3.30 [m, 1H, CH of η3-C3H5], 3.15 [d (6.6), 2H, Hsyn], 1.69 [d
(9.7), 2H, Hanti]. 13C{1H} NMR (CD2Cl2): 229.38 [CO], 154.01,
152.43, 138.06, 137.37, 131.02, 127.94, 125.82, 125.18 and
122.31 [bipy and C6H5], 78.22 [C2 of η3-C3H5], 56.76 [C1 and
C3 of η3-C3H5]. Anal. Calcd for C23H18MoN2O2: C, 61.34; H,
4.03; N, 6.22. Found: C, 61.47; H, 3.92; N, 5.98.
Syn th esis of [Mo(CtCSiMe3)(η3-C3H5)(CO)2(bip y)] (11).
To a solution of 1a (0.10 g, 0.26 mmol) in THF cooled to 195 K
was added a LiCtCSiMe3 solution prepared in situ by reaction
of HCtCSiMe3 (74 µL, 0.52 mmol) and nBuLi (0.83 mL of a
1.6 M solution in hexane, 0.52 mmol) in THF at 195 K. The
mixture was stirred for 1 h, and the workup was as described
for 10. Compound 11 was obtained as a red-brown solid.
Yield: 0.080 g, 70%. IR (CH2Cl2): 2015 (νCtC); 1937, 1850 (νCO).
1H NMR (CD2Cl2): 8.64, 8.13, 7.98 and 7.42 [m, 2H each, bipy],
3.42 [m, 1H, CH of η3-C3H5], 3.15 [d (6.6), 2H, Hsyn], 1.64
[d (9.9), 2H, Hanti], -0.38 [s, 9H, Mo-CtCSi(CH3)3]. 13C{1H}
NMR (CD2Cl2): 229.69 [CO], 154.22, 152.33, 137.96, 152.67
and 122.18 [bipy], 161.82 [Mo-CtC], 117.60 [Mo-CtC], 78.00
[C2 of η3-C3H5], 56.71 [C1 and C3 of η3-C3H5], 1.13 [Mo-CtCSi-
(CH3)3]. Anal. Calcd for C20H22MoN2O2Si: C, 53.81; H, 4.97;
N, 6.27. Found: C, 54.02; H, 4.95; N, 6.31.
[W(CtCH)(η3-C3H5)(CO)2(p h en )] (15). 15 was prepared
from [WCl(η3-C3H5)(CO)2(phen)] (2) (0.10 g, 0.20 mmol) and
NaCtCH. Yield: 0.08 g, 86% (dark red solid). IR (CH2Cl2):
1929 (νCtC); 1950, 1841 (νCO). 1H NMR (CD2Cl2): 9.12, 8.52,
7.99 and 7.79 [m, 2H each, phen], 3.10 [d (6.3), 2H, Hsyn], 2.12
[s, 1H, W-CtCH], 2.02 [m, 1H, CH of η3-C3H5], 1.88 [d (9.1),
2H, Hanti]. 13C{1H} NMR (CD2Cl2): 221.42 [CO], 152.35, 146.35,
137.27, 130.69, 127.72 and 125.53 [phen], 131.38 [Mo-CtC],
102.17 [Mo-CtC], 70.39 [C2 of η3-C3H5], 40.47 [C1 and C3 of
η3-C3H5]. Anal. Calcd for C19H14N2O2W: C, 46.94; H, 2.90; N,
5.76. Found: C, 46.96; H, 2.97; N, 5.68.
[W(CtCP h )(η3-C3H5)(CO)2(p h en )] (12). Compound 12
was prepared as described above for 10, from 2 (0.10 g, 0.20
mmol) and LiCtCPh (0.40 mmol). Yield (brown solid): 0.090
g, 78%. IR (CH2Cl2): 2082 (νCtC); 1929, 1838 (νCO). 1H NMR
(CD2Cl2): 9.18, 8.53, 8.00 and 7.81 [m, 2H each, phen], 6.87
[m, 3H, C6H5], 6.48 [m, 2H, C6H5], 3.19 [d (6.4), 2H, Hsyn], 2.34
[m, 1H, CH of η3-C3H5], 1.94 [d (9.4), 2H, Hanti]. 13C{1H} NMR
(CD2Cl2): 221.76 [CO], 152.36, 146.52, 137.23, 130.82, 130.63,
127.84, 127.65, 127.51, 125.46 and 125.34 [phen and C6H5],
139.59 [W-CtC], 116.32 [W-CtC], 70.60 [C2 of η3-C3H5], 40.81
[C1 and C3 of η3-C3H5]. Anal. Calcd for C23H18N2O2W: C, 53.40;
H, 3.23; N, 4.98. Found: C, 53.16; H, 3.19; N, 5.04.
Ack n ow led gm en t. We thank Ministerio de Ciencia
y Tecnolog´ıa (Projects MCT-00-BQU-0220, PB97-0470-
C02-01, and CICYT BQU2000-0219) and FICYT (PR-
01-GE-7) for financial support and for a predoctoral
fellowship (to L.R.). Anonymous reviewers are thanked
for criticism.
[W(CtCSiMe3)(η3-C3H5)(CO)2(p h en )] (13). Compound 13
was prepared analogously from 2 (0.10 g, 0.20 mmol) and LiCt
CSiMe3 (0.40 mmol). Yield: 0.100 g, 85% (red-brown solid).
IR (CH2Cl2): 2027 (νCtC); 1934, 1850 (νCO). 1H NMR (CD2Cl2):
9.08, 8.50, 7.97 and 7.74 [m, 2H each, phen], 3.18 [d (6.6), 2H,
Su p p or tin g In for m a tion Ava ila ble: Complete details for
the synthesis of alkylating reagents, complexes 1-5, [MoI(η3-
C3H5)(CO)2(phen)], and [Mo(CtCH)(η3-C3H5)(CO)2(phen)] (14b),
and tables giving positional and thermal parameters and bond
distances and angles for 9 and 10. This material is available
free of charge via the Internet at http://pubs.acs.org.
H
syn], 2.43 [m, 1H, CH of η3-C3H5], 1.87 [d (9.7), 2H, Hanti],
-0.27 [s, 9H, W-CtCSi(CH3)3]. 13C{1H} NMR (CD2Cl2): 222.15
[CO], 152.25, 146.80, 137.09, 130.74, 127.49 and 125.32 [phen],
117.98 [W-CtC], 93.34 [W-CtC], 70.28 [C2 of η3-C3H5], 48.67
OM0107800