Hydridic character and reactivity of Di[1,2-bis(dimethylphosphino)ethane]hydridonitrosylmolybdenum(0)

Article abstract of DOI:10.1021/om021032t

The synthesis of the tetraphosphine-substituted molybdenum hydride complex trans-Mo-(dmpe)₂(H)(NO) (3) (dmpe = bis(dimethylphosphino)ethane) is described, which is obtained by starting from the known compound Mo(CO) ₄(NO)(ClAlCl

Full text of DOI:10.1021/om021032t

3382
Organometallics 2003, 22, 3382-3393
Hyd r id ic Ch a r a cter a n d Rea ctivity of Di[1,2-bis-
(d im eth ylp h osp h in o)eth a n e]h yd r id on itr osylm olybd en u m (0)
Fupei Liang, Helmut W. Schmalle, Thomas Fox, and Heinz Berke*
Anorganisch-chemisches Institut, Universita¨t Zu¨rich, Winterthurerstrasse 190,
CH-8057 Zu¨rich, Switzerland
Received December 20, 2002
The synthesis of the tetraphosphine-substituted molybdenum hydride complex trans-Mo-
(dmpe)2(H)(NO) (3) (dmpe ) bis(dimethylphosphino)ethane) is described, which is obtained
by starting from the known compound Mo(CO)4(NO)(ClAlCl3) via the isolable chloride trans-
Mo(Cl)(dmpe)2(NO) (1) and the borohydride trans-Mo(η1-BH4)(dmpe)2(NO) (2). Two deuteride
complexes trans-Mo(dmpe)2(D)(NO) (3a ) and mer-Mo(CO)(D)(NO)(PMe3)3 (4) have been
prepared. From these the Mo-D bond ionicities of both deuterides were obtained via
determinations of the deuterium quadrupole coupling constants (DQCC) in solution from
2
2
T1min measurements of the H nucleus and in solid state from static H NMR spectra. A
strongly polar character of the Mo-D(H) bond was found for 3 and 4. In agreement with its
enhanced hydridicity 3 revealed a very high propensity for hydride transfer reactions. It
reacted readily with benzophenone, acetophenone, and acetone to afford the corresponding
alkoxide complexes trans-Mo(dmpe)2(NO)(OCHRR′) (R ) R′ ) Ph (5); R ) Me, R′ ) Ph (6);
R ) R′ ) Me (7)). 3 also underwent rapid insertion with Fe(CO)5 and Re2(CO)10 to afford
µ-formyl complexes Mo(dmpe)2(NO)[(µ-OCH)Fe(CO)4] (8) and Mo(dmpe)2(NO)[(µ-OCH)Re2-
(CO)9] (9), respectively. Furthermore, reversible double insertion of 3 into Re2(CO)10 was
observed, which furnished the (ON)(dmpe)2Mo(µ-OCH)Re2(CO)8(µ-CHO)Mo(dmpe)2(NO)
complex (10). For this reaction equilibrium constants were determined by VT-NMR
measurements. ∆H and ∆S amount to -58.8 ( 2.7 kJ mol-1 and -48 ( 2 J ‚K-1.mol-1. The
reaction of 3 with Mn2(CO)10 gave the µ-carbonyl complex Mo(dmpe)2(NO)[(µ-OC)Mn(CO)4]
(12) via the intermediacy of Mo(dmpe)2(NO)[(µ-OCH)Mn2(CO)9] (11). The structures of
compounds 1, 2, 8, 9, 10, and 12 were studied by single-crystal X-ray diffraction.
In tr od u ction
ligands and additionally strongly σ-donating phosphines
as cis-ligands have been studied.4 The LnM-H bond in
such compounds was characterized by their dihydrogen
bonding capabilities with weakly acidic substrates,5
bond ionicity determinations,6 and insertion behavior
as a chemical measure for their hydride transfer capa-
bilities.7 These studies allowed conclusions on the
hydridic character of the hydride ligands as the crucial
electronic factor for reactivity.
Transition metal hydrides are useful reagents in
many stoichiometric reactions and important intermedi-
ates in a large number of catalytic conversions.1 In many
such hydrogenations using transition metal hydrides the
proper balance of proton or hydride transfer capabilities
is important.2 In particular, this is the case for ionic
hydrogenations occurring with formal splitting of H2
into H- and H+ and the formation of transition metal
hydrides with a pronounced hydridic character. For
many years our group has systematically investigated
the ligand sphere tuning of the character of the LnM-H
bond.3 In this context, a series of octahedral transition
metal hydrides with nitrosyl or carbyne groups as trans-
We have previously reported studies on the chemistry
of mer-Mo(CO)(H)(NO)(PMe3)3.8 This hydride shows an
unusually high propensity to undergo the carbonyl
(4) (a) van der Zeijden, A. A. H.; Sontag, C.; Bosch, H. W.; Shklover,
V.; Berke, H.; Nanz, D.; von Philipsborn, W. Helv. Chim. Acta 1991,
74, 1194. (b) J a¨nicke, M.; Hund, H.-U.; Berke, H. Chem. Ber. 1991,
124, 719. (c) van der Zeijden, A. A. H.; Bu¨rgi, T.; Berke, H. Inorg. Chim.
Acta 1992, 201, 131. (d) Gusev, D. G.; Nietlispach, D.; Vimenits, A.;
Bakhmutov, V. I.; Berke, H. Inorg. Chem. 1993, 32, 3270. (e) Bakh-
mutov, V. I.; Bu¨rgi, T.; Burger, P.; Ruppli, U.; Berke, H. Organome-
tallics 1994, 13, 4203. (f) Gusev, D. G.; Llamazares, A.; Artus, G.;
J acobsen, H.; Berke, H. Organometallics 1999, 18, 75. (g) Baur, J .;
J acobsen, H.; Burger, P.; Artus, G.; Berke, H.; Dahlenburg, L. Eur. J .
Inorg. Chem. 2000, 1423. (h) Bannwart, E.; J acobsen, H.; Furno, F.;
Berke, H. Organometallics 2000, 19, 3605.
(5) (a) Shubina, E. S.; Belkova, N. V.; Krylov, A. N.; Vorontsov, E.
V.; Epstein, L. M.; Gusev, D. G.; Niedermann, M.; Berke, H. J . Am.
Chem. Soc. 1996, 118, 1105. (b) Belkova, N. V.; Shubina, E. S.; Ionidis,
A. V.; Epstein, L. M.; J acobsen, H.; Messmer, A.; Berke, H. Inorg.
Chem. 1997, 36, 1522. (c) Messmer, A.; J acobsen, H.; Berke, H. Chem.
Eur. J . 1999, 5, 3341.
(1) (a) Parshall, G. W.; Ittel, S. D. Homogeneous Catalysis, 2nd ed.;
J ohn Wiley & Sons: New York, 1992. (b) Darensbourg, M. Y.; Ash, C.
E. Adv. Organomet. Chem. 1987, 27, 1. (c) Brunet, J . J . Eur. J . Inorg.
Chem. 2000, 1377. (d) Ba¨ckvall, J .-E. J . Organomet. Chem. 2002, 652,
105.
(2) (a) Hembre, R. T.; McQueen, S. J . Am. Chem. Soc. 1994, 116,
2141. (b) Bullock, R. M.; Voges, M. H. J . Am. Chem. Soc. 2000, 122,
12594. (c) Magee, M. P.; Norton, J . R. J . Am. Chem. Soc. 2001, 123,
1778. (d) Casey, C. P.; Singer, S. W.; Powell, D. R.; Hayashi, R. K.;
Kavana, M. J . Am. Chem. Soc. 2001, 123, 1090. (e) Voges, M. H.;
Bullock, R. M. J . Chem. Soc., Dalton Trans. 2002, 759.
(3) (a) Berke, H.; Burger, P. Comments Inorg. Chem. 1994, 16, 279.
(b) J acobsen, H.; Berke, H. In Recent Advances in Hydride Chemistry;
Poli, R., Peruzzini, M., Eds.; Elsevier: Amsterdam, 2001; p 89. Kubas,
G. J . Metal Dihydrogen and R-Bond Complexes, Structures, Theory and
Reactivity; Kluwer Academic/Plenum Press: New York, 2001.
(6) Nietlispach, D.; Bakhmutov, V. I.; Berke, H. J . Am. Chem. Soc.
1993, 115, 9191.
10.1021/om021032t CCC: $25.00 © 2003 American Chemical Society
Publication on Web 07/16/2003

Tetraphosphine-Substituted Molybdenum Hydride
Organometallics, Vol. 22, No. 17, 2003 3383
Sch em e 1
insertion, which was mainly attributed to the trans
influence of the NO ligand and the three trimethylphos-
phine moieties. On this basis we decided to study a
hydride, with four cis phosphorus donors in the coordi-
nation sphere of the molybdenum center. For synthetic
reasons trans-Mo(dmpe)2(H)(NO) bearing two 1,2-bis-
(dimethylphosphino)ethane (dmpe) ligands with four
phosphorus donor links seemed to be an appropriate
choice. We anticipated that trans-Mo(dmpe)2(H)(NO)
would show optimum tuning properties and that it
therefore would exhibit a highly activated Mo-H bond.
It was indeed found that this complex inserted not only
molecules with CdO double bonds, like ketones and
metal carbonyl compounds, but also imine compounds
with the normally quite reluctant CdN double bond. In
this paper, we will present the synthesis, the Mo-H
bond ionicity determination, and the carbonyl insertion
behavior of trans-Mo(dmpe)2(H)(NO). The insertion
reaction of Mo(dmpe)2(H)(NO) with imines to afford
amido complexes will be reported elsewhere.
Resu lts a n d Discu ssion s
Syn th esis a n d Ch a r a cter iza tion of tr a n s-Mo-
(d m p e)2(H)(NO) (3). To our knowledge the only previ-
ously reported molybdenum hydride with nitrosyl and
bidentate phosphine ligands is trans-[MoH(NO)(d-
ppe)2].9 It was prepared refluxing a mixture of trans-
[Mo(N2)2(dppe)2], diethyl-N-nitrosoamine, and methanol
in THF under irradition, or by heating trans-[Mo(OH)-
(NO)(dppe)2] in methanol. However, these procedures
seemed to be very special and not suitable for gener-
alization, because, as we will see later for the hydride
with dmpe ligands, methanol may react with such
highly hydridic hydride. As previously reported8 the
hydride mer-Mo(CO)(H)(NO)(PMe3)3 was readily acces-
sible starting from the known compound trans-Mo(CO)4-
(NO)(ClAlCl3) via the corresponding chloride and boro-
hydride intermediates. We considered that access to the
hydride with dmpe ligands may also be achieved by a
related route. Indeed, the hydride trans-Mo(dmpe)2H-
(NO) (3) can be obtained via the isolable compounds Mo-
(dmpe)2(Cl)(NO) (1) and the borohydride complex Mo(η1-
BH4)(dmpe)2(NO) (2) (Scheme 1).
Ta ble 1. Selected Bon d Len gth s [Å] a n d Bon d
An gles [d eg] of 1
Mo(1)-N(1)
Mo(1)-P(1)
Mo(1)-P(2)
Mo(1)-Cl(1)
N(1)-O(1)
1.851(4)
N(1)-Mo(1)-P(2)
N(1)-Mo(1)-P(1)
P(2)-Mo(1)-P(1)
P(2)-Mo(1)-Cl(1)
P(1)-Mo(1)-Cl(1)
N(1)-Mo(1)-Cl(1)
91.30(9)
89.02(9)
80.850(14)
87.98(2)
91.08(3)
179.25(9)
2.4509(4)
2.4433(5)
2.4881(14)
1.187(4)
temperatures and long reaction times) is the remaining
CO ligand also replaced.
The structure of complex 1 was established on the
basis of IR and NMR spectroscopy, mass spectrometry,
and elemental analyses. The IR spectrum in THF shows
a band at 1553 cm-1, which corresponds to the NO
stretching vibration. The mass spectrum shows the
correct molecular peak for trans-MoCl(dmpe)2(NO)+,
1
and no higher peaks are found. The H NMR in C6D6
displays a singlet at 1.35 ppm and two multiplets at 1.45
and 1.24 ppm, which are assigned to the proton reso-
nances of the PMe and PCH2 groups, respectively. The
31P NMR reveals only a singlet at 35.4 ppm, indicating
the chemical equivalence of the four phosphorus atoms
around the molybdenum center and on this basis the
trans disposition of the chloride and nitrosyl ligand.
The molecular structure of chloride 1 was then
unambiguously assigned by a X-ray diffraction study.
Crystals suitable for the X-ray analysis were grown by
cooling a saturated diethyl ether solution of 1 to -30
°C. Selected bond distances and angles of the complex
are given in Table 1. The structure is shown in Figure
1. In accordance with the spectroscopic data, complex 1
has a pseudo-octahedral structure with four phosphorus
atoms in the equatorial plane and the trans-disposed
nitrosyl and chloride ligands, which display disorder.
Treatment of chloride 1 with excess LiBH4 in diethyl
ether resulted in the conversion of 1 to the borohydride
2 (Scheme 1). The isolation of 2 proved to be trouble-
some. It was ulitmately accomplished by repeated
extraction of the solid mixture with toluene, which
Reaction of trans-Mo(CO)4(NO)(ClAlCl3) with 3 equiv
of dmpe in an autoclave in THF at 160 °C for 8 days
produced the chloride 1 in high yield. On the basis of
the fact that the analogous reaction with PMe3 pro-
ceeded under milder conditions to afford trisphosphine-
substituted compound,8 the reaction with dmpe is
believed to undergo first facile substitution of two or
three CO groups and only under forcing conditions (high
(7) (a) Kundel, P.; Berke, H. J . Organomet. Chem. 1987, 335, 353.
(b) van der Zeijden, A. A. H.; Berke, H. Helv. Chim. Acta 1992, 75,
513. (c) van der Zeijden, A. A. H.; Bosch, H. W.; Berke, H. Organome-
tallics 1992, 11, 2051. (d) van der Zeijden, A. A. H.; Veghini, D.; Berke,
H. Inorg. Chem. 1992, 31, 5106. (e) van der Zeijden, A. A. H.; Berke,
H. Helv. Chim. Acta 1992, 75, 513. (f) Nietlispach, D.; Bosch, H. W.;
Berke, H. Chem. Ber. 1994, 127, 2403. (g) Nietlispach, D.; Veghini,
D.; Berke, H. Helv. Chim. Acta 1994, 77, 2197. (h) Furno, F.; Fox, T.;
Schmalle, H. W.; Berke, H. Organometallics 2000, 19, 3620. (i) Ho¨ck,
J .; J acobsen, H.; Schmalle, H. W.; Artus, G. R. J .; Fox, T.; Amor, J . I.;
Ba¨th, F.; Berke, H. Organometallics 2001, 20, 1533. (j) Furno, F.; Fox,
T.; Alfonso, M.; Berke, H. Eur. J . Inorg. Chem. 2001, 1559.
(8) Liang, F.; J acobsen, H.; Schmalle, H. W.; Fox, T.; Berke, H.
Organometallics 2000, 19, 1950.
(9) Kann, C. T.; Hitchcock, P. B.; Richards, R. L. J . Chem. Soc.,
Dalton Trans. 1982, 79.

3384 Organometallics, Vol. 22, No. 17, 2003
Liang et al.
F igu r e 1. ORTEP plot of the structure of 1. Displacement
ellipsoids are drawn with 50% probability. Labeling for the
symmetry-related atoms (sym.op.i ) -x+1, -y+1, -z) is
not shown. The hydrogen atoms have been omitted for
clarity.
F igu r e 2. ORTEP plot of the structure of 2. Displacement
ellipsoids are drawn with 50% probability. Labeling for the
symmetry-related atoms (sym.op.i ) -x+1, -y+1, -z) is
not shown. The hydrogen atoms except for those of BH4
have been omitted for clarity.
provided the product in only 20-30% yield in a first
batch. Redissolution of the residue in diethyl ether and
cooling of the resulting solution to -30 °C overnight and
then removal of the diethyl ether and extraction again
with toluene afforded further product. For a better
overall yield, it was necessary to repeat this inconve-
nient and time-consuming separation procedure four to
five times. It can be inferred that the difficulty of the
isolation of 2 originates from the formation of higher
lithium borohydride adducts, which in diethyl ether
partly release 2 in equilibrium quantities as demon-
strated by eq 1:
Ta ble 2. Selected Bon d Len gth s [Å] a n d Bon d
An gles [d eg] of 2
Mo(1)-N(1)
Mo(1)-P(1)
Mo(1)-P(2)
N(1)-O(1)
Mo(1)-H(2)
1.966(5)
2.4569(7)
2.4512(7)
1.172(9)
1.66(5)
N(1)-Mo(1)-P(2)
N(1)-Mo(1)-P(1)
P(2)-Mo(1)-P(1)
Mo(1)-H(2)-B(1)
N(1)-Mo(1)-H(2)
87.72(14)
91.78(15)
80.62(2)
150(6)
167(3)
spite the interference of the 11B quadrupolar relaxation,
which normally causes broadening. The observation of
a quintet at -42.1 ppm (1J HB ) 81 Hz) in the 11B NMR
spectrum additionally confirms the presence of the
tetrahydroborate group in the molecule.
[trans-Mo(dmpe)2(HBH3)(NO)]x[LiBH4]y h
x [trans-Mo(dmpe)2(HBH3)(NO)] + y LiBH4 (1)
By cooling a saturated diethyl ether solution of 2 to
-30 °C overnight crystals suitable for an X-ray diffrac-
tion study were obtained. A model of 2 is displayed in
Figure 2. Although there is disorder of the nitrosyl and
BH4 groups, the η1-binding mode of the BH4 unit in 2
is unambiguously established. This feature is similar
to that in Mo(η1-BH4)(CO)(NO)(PMe3)3, and it is thought
to be enforced by the residual ligand sphere providing
sufficient electronic saturation to the metal center. The
Mo-N and Mo-HBH4 bond distances of 2 (Table 2) are
apparently different from those of Mo(η1-BH4)(CO)(NO)-
(PMe3)3. However, any definite structural comparison
of these complexes, e.g., the influence of the phosphine
donors on the binding strengths of the nitrosyl and BH4
groups, is precluded by the inaccuracy of the structural
data due to the disorder of NO and BH4 units.
Conversion of the borohydride complexes into the
corresponding hydride compounds is accomplished by
the reaction with Lewis bases to remove BH3. As in the
case of the conversion of Mo(η1-BH4)(CO)(NO)(PMe3)3,8
we have tried to use trimethylphosphine as a borane
scavenger. But PMe3 turned out to be less effective in
the case of 2. Only 50% conversion of the borohydride 2
was observed after 4 days employing even up to 15 equiv
of PMe3 in toluene at room temperature. Alternatively,
quinuclidine can be used.4h,7h
The lithium borohydride-enriched species are appar-
ently insoluble in toluene, which allows the extraction
of 2 from a solid equlibrium mixture with this solvent.
It may be invoked that it is the coordination ability of
the nitrosyl group that promotes formation of these
adduct. LiBH4 or Li[HBR3] forms related adducts with
the chloride 1, as well as with the hydride 3.10
1
In the H NMR spectrum in C6D6 2 shows a charac-
teristic broad quartet at -2.26 ppm with a 11B coupling
1
constant of J HB ) 81 Hz, which corresponds to the
proton resonance of the tetrahydroborate group. The
signal does not reveal further splitting at -60 °C in
C7D8, indicating a fast exchange process between the
bridging and nonbridging H atoms of the BH4 group
even at low temperature. In C6D6 two singlets at 1.40,
1.26 ppm and two multiplets at 1.47, 1.19 ppm are
assigned to the resonances of the PMe and PCH2 group
protons, respectively. The 31P NMR spectrum in C6D6
displays a singlet at 36.2 ppm, corresponding to the four
chemically equivalent phosphorus atoms of the phos-
phine ligands. In contrast to the previously reported
borohydride Mo(η1-BH4)(CO)(NO)(PMe3)3 and other
8
boron-containing compounds,11 sharp signals of the
proton and phosphorus resonances were observed, de-
(10) Liang, F. Ph.D. Thesis, University of Zurich, 2001.
(11) (a) Beall, H.; Bushweller, C. H. Chem. Rev. 1973, 73, 465. (b)
Marks, T. J .; Kolb, J . R. Chem. Rev. 1977, 77, 263.
Treatment of 2 with 8 equiv of quinuclidine in toluene
at room temperature for 2 days produced the desired

Tetraphosphine-Substituted Molybdenum Hydride
Organometallics, Vol. 22, No. 17, 2003 3385
hydride 3. The removal of the R3N f BH3 byproducts
and the excess of quinuclidine was achieved by extrac-
tion of the reaction mixture with pentane and subse-
quent sublimation of the impurities at 60 °C in vacuo.
The hydride 3 was finally isolated in yields over 90%.
In the IR spectrum of 3 in THF the NO stretching
vibration was found at 1557 cm-1. Similar to the case
of mer-Mo(CO)(H)(NO)(PMe3)3, the Mo-H bond vibra-
tion of 3 could not be observed. The 1H NMR of 3 in
C6D6 shows besides the proton resonances of the PMe
and PCH2 groups a quintet at -4.58 ppm due to the
coupling with the four chemically equivalent phosphorus
nuclei (2J HP ) 29 Hz). Compared with the corresponding
hydride resonance of mer-Mo(CO)(H)(NO)(PMe3)3 (-1.92
ppm), that of 3 appears at relatively high field. The 31P
NMR spectrum displays a singlet at 44.2 ppm.
Ion icities of th e Mo-D bon ds of tr a n s-Mo(dm pe)2-
(D)(NO) (3a ) a n d m er -Mo(CO)-(D)(NO)(P Me3)3 (4).
Our group has previously reported the determination
of bond ionicities (i) of a series of transition metal
deuterides via the T1min measurements of the 2H nucleus
in solution and used the bond ionicity as an indicator
of the hydridic character of the LnM-H bond.6 For this
the deuterides trans-Mo(dmpe)2(D)(NO) (3a ) and mer-
Mo(CO)(D)(NO)(PMe3)3 (4) had to be prepared.
3a and 4 were synthesized analogously to the corre-
sponding H compounds. An equimolar mixture of NaBD4
and LiCl was used as a substitute for LiBH4 in the
conversions of the chlorides to the borohydrides. The 2H
NMR T1 relaxation times for both deuterides have been
measured in toluene-h8 at different temperatures, which
resulted in values of T1min of 53 and 48 ms for 3a and
4, respectively. Accordingly, the deuterium quadrupole
coupling constants (DQCCs) were calculated to be 36 (
1 and 38 ( 1 kHz, and the ionicities of the Mo-D(H)
bonds are 84.1 ( 0.5% and 83.3 ( 0.5% for 3a and 4,
respectively. These bond ionicity values are significantly
larger than those reported previously for related ni-
trosyl-substituted transition metal deuterides6 such as
Re(CO)D2(NO)(PMe3)2 and W(CO)2D(NO)(PMe3)2, span-
ning a range from 69% to 76%, and they are close to
the value of 86% for LiD.12 This stresses the strong
polarity of the Mo-D bond in both complexes. These
highly polar characters for the Mo-D bonds in 3a and
4 may be attributed to the electronic effects of the ligand
sphere, specifically to the electron-donating property of
the phosphines and to the trans influence of the nitrosyl
group. The bond ionicity of 3a is somewhat larger than
that of 4, which, if significant, may reflect the higher
number of phosphine substitutents.
2
F igu r e 3. Static solid-state H NMR spectra of 4 (above)
and 3a (below) at various temperatures. The chemical shift
(Hz) of the center resonance has been arbitrarily set to zero.
state 2H NMR spectra of 3a and 4 are presented in
Figure 3. From the spectra the ∆ values of 36 and 39
kHz are obtained, DQCCs are calculated amounting to
48 ( 0.2 and 52 ( 0.2 kHz, and the bond ionicity i values
are 78.8 ( 0.1% and 77.1 ( 0.1% for 3a and 4,
respectively. The results indicate again that the hydridic
polarization of the Mo-D bond is stronger in 3a than
in 4. However, the DQCCs of both complexes 3a and 4
obtained from the measurements in solution are smaller
than those determined in the solid state. A similar
situation has been observed for W(CO)(D)(NO)(PMe3)3.14
This difference is probably due to an electrical field
anisotropy in the solid state. Since the two peaks of the
“Pake doublet”13 are broadened and the outside line
components are not observable due to strong dipolar
interactions with the neighboring 31P nuclei, it was not
possible to use simulation techniques to correct for the
anisotropy.
In addition the DQCCs of 3a and 4 were determined
by the rarely used solid-state 2H NMR method. The
following correlation is valid:13
DQCC ) (4/3)I∆(1-η)
where I is the nuclear spin of the 2H nucleus, ∆ is
defined as the distance between the two outer signals
in the solid-state 2H NMR spectrum, and η is the
asymmetry parameter of the electrical field. In an
isotropric solid system η would be zero. The VT solid-
2
It is noteworthy that the solid-state H NMR of 3a
and 4 display unexpected temperature dependencies in
the range -20 to +50 °C (Figure 3). For 4 a singlet
resonance can be observed at high temperature (55 °C),
while at low temperature (-20 °C), this resonance
(12) Wharton, L.; Gold, L. P.; Klemperer, W. J . Chem. Phys. 1962,
37, 2149.
(13) Fyfe, C. A. Solid State NMR for Chemists; CFC Press: Guelph,
1983.
(14) Ho¨ck, J . Ph.D. Thesis, University of Zurich, 2001.

3386 Organometallics, Vol. 22, No. 17, 2003
Liang et al.
Sch em e 2
becomes very weak and is replaced by the expected
“Pake doublet”. Such temperature dependence of the
2
solid-state H NMR spectra is similar to that observed
for W(CO)(D)(NO)(PMe3)314 and W(tCMes)(D)(dmpe)2,15
where the singlet resonance even fully disappeared at
low temperature (-30 and -40 °C, respectively). This
phenomenon is believed to result from 2H mobility in
2
the solid state of 4. The solid-state H NMR spectrum
of 3a displays a singlet over the whole available tem-
perature range. This is again interpreted in terms of
exchange and consequently mobility of the D ligand,
however, apparently occurring with an even lower
barrier than for 4. Although the observation is new and
a mechanism not yet available, it seems to be a general
characteristic for hydridic hydrides. Further detailed
work has to be carried out to trace the real cause and
the mechanism of this mobility behavior.
Rea ctivity of tr a n s-Mo(d m p e)2(H)(NO) (3). Con-
sidering the high reactivity of the hydride mer-Mo(CO)-
8
(H)(NO)(PMe3)3 and its high hydridic character of the
Mo-H bond, we may anticipate that the activity of such
hydrides parallels their hydridicity. The fact that hy-
dride 3 possesses an even enhanced hydridic Mo-H
bond led us to suspect that 3 would show an increased
propensity to undergo hydride transfer reactions. There-
fore, it was of great interest to test the insertion
capabilities of 3. Furthermore, insertion reactions of
metal hydrides are of fundamental importance, repre-
senting key steps in many catalytic transformations of
unsaturated substrates with transition metal com-
pounds.16 In this study simple ketones and metal car-
bonyl compounds were chosen as relatively polar sub-
strates, since they were supposed to react with a rela-
tively greater ease with polar hydride transfer agents.
Reactions of 3 with benzophenone, acetophenone, and
acetone were completed in 2, 1.5, and 3 h, respectively,
under otherwise mild conditions to afford the corre-
sponding alkoxide complexes trans-Mo(dmpe)2(NO)-
(OCHRR′) (R ) R′ ) Ph (5); R ) Me, R′ ) Ph (6); R )
R′ ) Me (7)). The reaction times are short compared
with the corresponding ones of mer-Mo(CO)(H)(NO)-
(PMe3)3 (3, 7, 10 h for Ph2CO, PhCOMe, Me2CO,
respectively) (Scheme 2). In contrast to the case of mer-
Mo(CO)(H)(NO)(PMe3)3, the reaction times of 3 with the
three ketones vary only little in dependence of the
electrophilic character of the Ccarbonyl atom. This lower
selectivity is presumably due to the fact that 3 is a
“hotter” species and the whole reaction profile more
exothermic so that the ability for kinetic distinction is
greatly reduced.
spectroscopy. The 1H NMR spectrum of 5 in C6D6 shows
among other resonances a characteristic singlet at 5.03
ppm, which corresponds to the proton resonance of the
newly formed -CH- moiety. In the 13C NMR spectrum
the characteristic resonance for this carbon atom ap-
pears at 85.3 ppm as a quintet signal. The splitting of
the signal results from the coupling with the four
phosphorus nuclei. The newly formed -CH- moiety for
1
6 appears in the H NMR spectrum at 4.14 ppm split
into a quartet signal due to coupling with the methyl
group. The resonance of the respective carbon atom was
observed as a quintet at 77.5 ppm in the 13C NMR
spectrum. The methyl groups of the dmpe ligands of 6
are diastereotopic due to the chiral center at the carbon,
which causes two sets of multiplets in the 1H NMR
spectrum at 1.30 and 1.22 ppm. This diastereotopy is
also reflected in the 31P{1H} NMR spectrum, where not
the expected singlet but a symmetric higher order
multiplet is observed at 32.4 ppm. For complex 7 the
1H NMR displays also a characteristic heptet resonance
at 3.25 ppm for the newly formed -CH- moiety. The
13C{1H} NMR shows for this CH group a quintet at 69.3
ppm.
Treatment of 3 with 1 equiv of Fe(CO)5 in toluene at
room temperature afforded the formyl-bridged complex
trans-Mo(dmpe)2(NO)[(µ-OCH)Fe(CO)4] (8) in a few
minutes (Scheme 2). 8 was found to be insoluble in
pentane, sparingly soluble in toluene, and soluble in
THF. After diffusion of pentane into a concentrated THF
solution the complex was isolated as orange crystals in
81% yield. The IR spectrum of 8 in THF displays three
bands at 2032, 1949, and 1918 cm-1 attributed to ν(CO)
vibrations of the Fe(CO)4 moiety. These spectroscopic
data are very similar to those of the analogous complex
mer-Mo(CO)(NO)(PMe3)3[(µ-OCH)Fe(CO)4]8 and the “par-
The alkoxide complexes 5, 6, and 7 have been fully
characterized by elemental analysis, MS, IR, and NMR
(15) Furno, F. Ph.D. Thesis, University of Zurich, 2001.
(16) Selected references: (a) Gladysz, J . A. Adv. Organomet. Chem.
1982, 20, 1. (b) Blackborow, J . R.; Daroda, R. J .; Wilkinson, G. Coord.
Chem. Rev. 1982, 43, 17. (c) Darensbourg, D. J .; Kudaroski, R. A. Adv.
Organomet. Chem. 1983, 22, 129. (d) Costa, L. C. Catal. Rev. Sci. Eng.
1983, 25, 325. (e) Dombek, B. P. Adv. Catal. 1983, 32, 325. (f) Noyori,
R.; Takaya, H. Acc. Chem. Res. 1990, 23, 345. (g) Klingler, R. J .;
Rathke, J . W. Prog. Inorg. Chem. 1991, 39, 113. (h) Su¨ss-Fink, G.;
Meister, G. Adv. Organomet. Chem. 1993, 35, 41. (i) Miller, R. L.;
Toreki, R.; La Pointe, R. E.; Wolczanski, P. T.; Van Duyne, G. D.; Roe,
D. C. J . Am. Chem. Soc. 1993, 115, 5570. (j) Simpson, M. C.; Cole
Hamilton, D. J . Coord. Chem. Rev. 1996, 155, 163. (k) Gibson, D. H.
Chem. Rev. 1996, 96, 2063. (l) Burk, M. J .; Gross, M. F.; Harper, T. G.
P.; Kalberg, C. S.; Lee, J . R.; Martinez, J . P. Pure Appl. Chem. 1996,
68, 37. (m) Nomura, K. J . Mol. Catal. A: Chem. 1998, 130, 1. (n)
Palmer, M. J .; Wills, M. Tetrahedron: Asymmetry 1999, 10, 2045.
1
ent” [Fe(CO)4CHO]- anion.17 In the H NMR spectrum
of 8 (C6D6) the characteristic proton resonance of the
bridging formyl group appears at 13.52 ppm as a singlet.
In the 13C{1H} NMR spectrum the resonance for the
carbon atom of this bridging formyl group is observed
at 299.3 ppm as a quintet.
(17) Collman, J . P.; Winter, S. R. J . Am. Chem. Soc. 1973, 95, 4089.

Tetraphosphine-Substituted Molybdenum Hydride
Organometallics, Vol. 22, No. 17, 2003 3387
F igu r e 5. ORTEP plot of the structure of 9. Displacement
ellipsoids are drawn with 50% probability. The hydrogen
atoms, except H2, have been omitted for clarity.
F igu r e 4. ORTEP plot of the structure of 8. Displacement
ellipsoids are drawn with 50% probability. Labeling for
symmetry-related atoms is not shown (sym. op. i ) -x+2,
y, z). The hydrogen atoms, except H7, have been omitted
for clarity.
Ta ble 4. Selected Bon d Len gth s [Å] a n d Bon d
An gles [d eg] of 9
Ta ble 3. Selected Bon d Len gth s [Å] a n d Bon d
An gles [d eg] of 8
Mo-N(1)
Mo-O(2)
Mo-P(1)
Mo-P(2)
Mo-P(3)
Mo-P(4)
N(1)-O(1)
C(2)-O(2)
Re(1)-C(2)
1.781(8)
2.258(8)
2.466(2)
2.454(3)
2.542(5)
2.407(5)
1.200(12)
0.914(15)
2.180(14)
N(1)-Mo-P(1)
N(1)-Mo-P(2)
N(1)-Mo-P(3)
N(1)-Mo-P(4)
N(1)-Mo-O(2)
P(1)-Mo-P(3)
P(4)-Mo-P(2)
O(2)-C(2)-Re(1)
C(2)-O(2)-Mo
88.9(3)
88.5(3)
82.5(3)
94.7(3)
164.1(4)
80.1(2)
80.7(2)
169.2(13)
164.8(11)
Mo-N(1)
Mo-O(2)
Mo-P(1)
Mo-P(2)
N(1)-O(1)
C(7)-O(2)
Fe-C(7)
1.791(5)
2.188(6)
N(1)-Mo-P(2)
N(1)-Mo-P(1)
P(2)-Mo-P(1)
O(2)-Mo-P(1)
O(2)-Mo-P(2)
C(7)-O(2)-Mo
O(2)-C(7)-Fe
91.18(12)
91.32(12)
80.35(4)
87.30(12)
90.20(12)
145.7(8)
2.4646(11)
2.4677(11)
1.205(7)
1.119(12)
1.953(11)
136.3(10)
the analogous complexes bearing the formyl groups in
equatorial positions.8,18 The Mo-N(1) distance of 1.781-
(8) Å of complex 9 (Table 4) does not reveal a significant
difference compared to the corresponding distance of the
previously reported complex mer-Mo(CO)(NO)(PMe3)3-
[(µ-OCH)Re2(CO)9] (1.772(6) Å);8 however the Mo-O(2)
distance of 2.258(8) Å and the Re(1)-C(2) distance of
2.180(14) Å in 9 are much longer than those in the
related complex bearing PMe3 ligands (2.173(5) and
2.102(7) Å, respectively). This indicates greater steric
repulsion at the level of a higher degree of phosphine
substitution. This influence is also reflected in the bond
angles of the Mo-O-C-Re bridge. In the complex mer-
Mo(CO)(NO)(PMe3)3[(µ-OCH)Re2(CO)9], the C(11)-O(3)-
Mo angle (127.8(5)°) and the O(3)-C(11)-Re(1) angle
(127.5(5)°) show much greater bends than those of
complex 9 (Table 4, corresponding bond angles are
164.8(11)° and 169.2(13)°). It is assumed that the
difference arises from steric factors. Again in complex
9 there is greater steric crowding of the dmpe ligands,
which prevents the Mo(dmpe)2(NO) fragment to come
closer to the Re2(CO)9 unit.
The hydride transfer reaction of 3 with Fe(CO)5 did
not show fundamental deviations from that of mer-Mo-
(CO)(H)(NO)(PMe3)3.8 Both reactions proceeded rapidly
to completion at room temperature. In contrast to this,
the reactions of both hydrides with Re2(CO)10 are
significantly different. While the reaction of mer-Mo-
(CO)(H)(NO)(PMe3)3 with Re2(CO)10 establishes an equi-
librium, the corresponding reaction of 3 proceeded to
completion, which reflects a less activated Mo-H bond
for 3. More interestingly, further reaction of complex 9
with 3 established double insertion of 3 into Re2(CO)10.
Crystals suitable for X-ray diffraction analysis of 8
were obtained by diffusion of pentane into a THF
solution of the complex. The molecular structure of 8 is
shown in Figure 4. The complex reveals an octahedral
coordination around the molybdenum center, which is
very similar to those of complexes 1 and 2. The
coordination around the iron center is pseudo-trigonal
bipyramidal. Both the Mo-N(1) and Mo-O(2) distances
(Table 3, 1.791(5) and 2.188(6) Å, respectively) of 8 are
only a little longer (about 0.015 Å) than the correspond-
ing distances in complex mer-Mo(CO)(NO)(PMe3)3[(µ-
OCH)Fe(CO)4],8 suggesting similar binding strengths of
the nitrosyl and the bridging formyl groups in both
species. The C(7)-O(2)-Mo angle of 145.7(8)° and the
O(2)-C(7)-Fe angle of 136.3(10)° in 8 are comparable
to the corresponding ones in mer-Mo(CO)(NO)(PMe3)3-
[(µ-OCH)Fe(CO)4], indicating only marginal influence
of the different phosphine environments of both com-
pounds.
Reaction of 3 with 1 equiv of Re2(CO)10 in toluene
proceeded to completion at room temperature with
formation of the corresponding formyl-bridged complex
trans-Mo(dmpe)2(NO)[(µ-OCH)Re2(CO)9] (9). The reac-
tion was over in a few minutes, and the product was
isolated as orange crystals in 86% yield. In the 1H NMR
spectrum of 9 (in C6D6) the characteristic resonance of
the formyl proton is observed as a singlet at 14.57 ppm.
The 13C{1H} NMR displays a multiplet at 298.4 ppm
for the resonance of the formyl carbon atom.
Diffusion of pentane into a concentrated toluene
solution of complex 9 gave crystals suitable for an X-ray
diffraction study. As shown in Figure 5 the molybdenum
center in 9 adopts a pseudo-octahedral geometry as in
the series of complexes 1, 2, and 8. The geometry of the
[Re2(CO)9CHO] fragment is grossly similar to that of
(18) Casey, C. P.; Neumann, S. M. J . Am. Chem. Soc. 1978, 100,
2544.

3388 Organometallics, Vol. 22, No. 17, 2003
Liang et al.
Sch em e 3
F igu r e 6. 1D-EXSY spectrum of the reaction mixture in
Scheme 2 (C7D8, 333 K).
F igu r e 7. Van’t Hoff plot for the equilibrium reaction of
9 with 3 to give 10 as shown in Scheme 3. ∆H and ∆S
values are given in the text.
reaction is moderately exothermic, which apparently can
be related to the relatively weak Mo-H bond of 3, and
the quite negative entropy value speaks for the associa-
tive nature of the reaction.
Even in the 1H NMR spectrum of the equimolar mixture
of 3 and Re2(CO)10 (in C7D8) a new singlet appeared at
14.66 ppm besides the signal at 14.57 ppm for the formyl
group of 9, suggesting the formation of the new com-
pound 10, also bearing formyl groups. In the 31P{1H}
spectrum of the same mixture a new singlet was
observed at 36.5 ppm besides the signals of 3 and 9,
confirming further the existence of a new species. We
assume that the new compound 10 is the product of a
second insertion reaction of 3 with 9. The observations
of the coexistence of the signals corresponding to 3, 9,
and the new complex 10 in the mixture of all these
constituents and the temperature-dependence of the
integrals of these signals indicate that the subsequent
transformation of 3 with 9 is a reversible process
(Scheme 3). The occurrence of an equilibrium was
confirmed by a 1D-EXSY experiment. When the hydride
signal of 3 at -4.72 ppm was irradiated, apparent
exchange of the signals at 14.57 and 14.66 ppm (reso-
nances for the formyl protons of 9 and 10, respectively)
was clearly indicated (Figure 6).
Due to the equilibrium reaction depicted in Scheme
3, 10 could not be isolated as an analytically pure
sample, since 10 tends to cocrystallize with 9, thus
impeding its full characterization by IR, NMR spectros-
copy, and elemental analysis. But the molecular struc-
ture of 10 has been established unambiguously by
single-crystal X-ray diffraction. A few crystals suitable
for this study were obtained by diffusion of pentane into
a concentrated toluene mixture containing 9 with 4
equiv of 3. Under these conditions complex 10 crystal-
lized as a toluene solvate. An ORTEP drawing of 10 is
given in Figure 8. For clarity the toluene solvate
molecule is omitted. Selected bond distances and angles
are given in Table 5. The structure shows clearly that
insertions of two molecules of 3 into one Re2(CO)10
occurred. Each Re(CO)5 unit of Re2(CO)10 bears one
inserted hydride molecule, and the two units are ar-
ranged in an anti-conformation. Both of the bridging
formyl groups are located in equatorial positions of the
Re(CO)5 moieties. The corresponding bond lengths and
angles of the two Re-C-O-Mo bridges of the formyl
groups are almost equal, and in contrast to the situation
of complex 9, they do not show great differences when
compared with those of the corresponding bond lengths
and angles of mer-Mo(CO)(NO)(PMe3)3[(µ-OCH)Re2-
(CO)9], indicating in this case only minor stereoelec-
The equilibrium constant K of the reaction of 3 with
9 shown in Scheme 3 has been determined by NMR
spectroscopy in THF-d8 at variable temperatures. At 298
K the K value was 1.99 L/mol, indicating that the
equilibrium lies mainly to the left side of the reaction.
From the van’t Hoff plot depicted in Figure 7, ∆H and
∆S were calculated to be -58.8 ( 2.7 kJ ‚mol-1 and -48
( 2 J ‚K-1‚mol-1. The ∆H value indicates that the

Tetraphosphine-Substituted Molybdenum Hydride
Organometallics, Vol. 22, No. 17, 2003 3389
Sch em e 4
F igu r e 8. ORTEP plot of the structure of 10. Displace-
ment ellipsoids are drawn with 50% probability. The
hydrogen atoms, except H29 and H30, have been omitted
for clarity.
Ta ble 5. Selected Bon d Len gth s [Å] a n d Bon d
An gles [d eg] of 10
Mo(1)-N(1)
Mo(1)-O(8)
Mo(1)-P(1)
Mo(1)-P(2)
Mo(1)-P(3)
Mo(1)-P(4)
N(1)-O(1)
1.782(7)
2.207(5)
2.449(2)
2.458(2)
2.465(2)
2.463(2)
1.212(10)
1.230(10)
2.140(8)
1.771(7)
2.194(5)
2.457(2)
2.467(2)
2.444(2)
2.449(2)
1.223(10)
1.251(10)
2.132(8)
N(1)-Mo(1)-P(1)
N(1)-Mo(1)-P(2)
N(1)-Mo(1)-P(3)
N(1)-Mo(1)-P(4)
N(1)-Mo(1)-O(8)
P(1)-Mo(1)-P(2)
P(4)-Mo(1)-P(3)
O(8)-C(30)-Re(1)
C(30)-O(8)-Mo(1)
N(2)-Mo(2)-P(5)
N(2)-Mo(2)-P(6)
N(2)-Mo(2)-P(7)
N(2)-Mo(2)-P(8)
N(2)-Mo(2)-O(7)
P(5)-Mo(2)-P(6)
P(7)-Mo(2)-P(8)
O(7)-C(29)-Re(2)
C(29)-O(7)-Mo(2)
89.2(3)
92.7(3)
87.5(3)
91.5(2)
176.6(3)
80.69(9)
80.00(8)
127.6(6)
134.5(5)
90.5(2)
89.5(3)
90.7(3)
90.6(2)
175.4(3)
80.22(8)
80.87(8)
127.8(6)
135.8(5)
C(30)-O(8)
Re(1)-C(30)
Mo(2)-N(2)
Mo(2)-O(7)
Mo(2)-P(5)
Mo(2)-P(6)
Mo(2)-P(7)
Mo(2)-P(8)
N(2)-O(2)
attacks the hydridic species 3 to again deliver 12 and
H2, and this step is assumed to be faster the higher the
concentration of 3 is. The involvement of HMn(CO)5 was
probed in a separate experiment and was found to react
readily with 3 in the proposed fashion. This provides
evidence that especially the last step of Scheme 4 is
based on realistic grounds.
C(29)-O(7)
Re(2)-C(29)
1
In the H NMR spectrum (C7D8, room temperature)
11 revealed a characteristic singlet at 13.51 ppm as-
signed to the formyl proton. A singlet at 33.9 ppm in
the 31P{1H} NMR spectrum belongs to the phosphorus
nuclei of 11. Compound 12 was isolated from the
reaction mixture as analytically pure, yellow crystals
tronic influences of the dmpe ligands on the structure
of the formyl group. The reasons for this remain to be
explained.
It was of further interest to extend the study to the
reaction of 3 with Mn2(CO)10,19 which displays a weaker
metal-metal bond and therefore was expected to show
a different reaction pattern. The reaction of 3 with
equimolar amounts of Mn2(CO)10 was carried out in
C7D8 and monitored by NMR spectroscopy. From the
time-dependent 1H and 31P{1H} NMR spectra of the
reaction mixture, one could see that 3 was consumed
in a few minutes to yield the new compound trans-Mo-
(dmpe)2(NO)[(µ-OCH)Mn2(CO)9], 11, in analogy with the
reaction with Re2(CO)10 (Scheme 4). However, in con-
trast to 9, 11 was quite unstable and decomposed into
another complex, trans-Mo(dmpe)2(NO)[(µ-OC)Mn(CO)4]
(12) within 2 days. Attempts to isolate and further
characterize complex 11 were unsuccessful. The mech-
anism for the conversion of 11 into 12 could not fully
be traced. A mechanistic scheme is suggested in accord
with that found by J . A. Gladysz et al.25 for the cleavage
of Mn2(CO)10 by LiHB(C2H5)3 Superhydride (Scheme 4).
1
in 73% yield. The H NMR of 12 in C6D6 displays two
multiplets at 1.21, 1.02 ppm and two singlets at 1.16,
1.07 ppm, which can be assigned to the resonances of
the CH2 and CH3 groups of the dmpe ligands. The 31P-
{1H} NMR in C6D6 merely shows a singlet at 36.0 ppm.
In the 13C{1H} NMR spectrum a quintet at 29.1 ppm
and a multiplet at 14.3 ppm were observed for the C
nuclei of the dmpe ligands, and furthermore multiplets
(20) Darensbourg, M. Y.; Darensbourg, D. J .; Burns, D.; Drew, D.
A. J . Am. Chem. Soc. 1976, 98, 3127.
(21) Horwitz, C. P.; Shriver, D. F. Adv. Organomet. Chem. 1984,
23, 219.
(22) (a) Schneider, M.; Weiss, E. J . Organomet. Chem. 1976, 121,
365. (b) Tilley, T. D.; Andersen, R. A. J . Chem. Soc., Chem. Commun.
1981, 985. (c) Marsella, J . A.; Huffmann, J . C.; Caulton, K. G.; Longato,
B.; Norton, J . R. J . Am. Chem. Chem. 1982, 104, 6360. (d) Merola, J .
S.; Gentile, R. A.; Ansel, G. B.; Modrick, M. A.; Zenta, S. Organome-
tallics 1982, 1, 1731. (e) Merola, J . S.; Campo, K. S.; Gentile, R. A.;
Modrick, M. A.; Zenta, S. Organometallics 1984, 3, 334. (f) Sartain,
W. J .; Selegue, J . P. Organometallics 1984, 3, 1922. (g) Boncella, J .
M.; Andersen, R. A. Inorg. Chem. 1984, 23, 432. (h) Osborne, J . H.;
Rheingold, A. L.; Trogler, W. C. J . Am. Chem. Soc. 1985, 107, 6292.
(23) Hamilton, D. M.; Willis, W. S.; Stucky, G. D. J , Am. Chem.
Chem. 1981, 103, 4255.
(24) (a) Clegg, W.; Wheatley, P. J . J . Chem. Soc. A 1971, 3572. (b)
Frenz, B. A.; Ibers, J . A. Inorg. Chem. 1972, 11, 1109. (c) Katacher,
M. L.; Simon, G. L. Inorg. Chem. 1972, 11, 1651. (d) Clegg, W.;
Wheatley, P. J . J . Chem. Soc., Dalton Trans. 1973, 90; 1974, 424. (e)
Herberhold, M.; Wehrmann, F.; Neugebauer, D.; Huttner, G. G. J .
Organomet. Chem. 1978, 152, 329.
-
Via the intermediacy of HMn(CO)5, Mn(CO)5 and H2
are formed. H2 also evolves from the reaction according
to Scheme 4 (signal at 4.45 ppm), which is found to be
accelerated in the presence of an excess of 3. This may
imply that in 11 Mn(CO)5- acts first as a leaving group
and then as a weak base. Subsequently 12 and the
acidic hydride HMn(CO)5 are formed. The latter then
(25) Gladysz, J . A.; Williams, G. M.; Tam, W.; J ohnson, D. L. J .
Organomet. Chem. 1977, 140, C1.
(19) Meyer, T. J . Prog. Inorg. Chem. 1975, 19, 1.

3390 Organometallics, Vol. 22, No. 17, 2003
Liang et al.
µ-OC carbonyl, usually possess oxophilic main group
metals, f group elements, or early transition metals as
the acceptors of the OCO atom. To our knowledge
complex 12 is the first structurally characterized case
with the oxygen of the µ-OC moiety binding to a mid
transition metal center. The alternative metal-metal
bonded structure [(dmpe)2(NO)Mo-Mn(CO)5] isomeric
to 12 is presumably not formed, because of a too weak
heterobimetallic Mo-Mn interaction. The Mn(CO)5
fragment in 12 adopts a trigonal-bipyramidal structure
similar to those found in related complexes.24 It is one
of the equatorial carbonyl groups that acts as the
bridging ligand connecting to the Mo(dmpe)2(NO) frag-
ment. The angles of O(2)-C(1)-Mn(1) and C(1)-O(2)-
Mo(1) are 179.2(3)° and 159.0(3)°, respectively. The
latter shows a relatively large bend, which however
resembles those found in previously reported examples
of µ-OC bridges.22,23 The average length of the terminal
Mn-C bonds is 1.828(5) Å larger than the length of the
bridging Mn-C bond of 1.759(4) Å, whereas the average
distance of 1.145(5) Å for the terminal CO groups is
shorter than the distance of 1.180(5) Å for the bridging
C-O bond. The shortening of the Mn-C bond and the
lengthening of the C-O bond for the µ-OC carbonyl
group are consistent with the idea that the formation
of the bridging bonds increases the participation of CO
π* character.23
F igu r e 9. ORTEP plot of the structure of 12. Displace-
ment ellipsoids are drawn with 50% probability. The
hydrogen atoms have been omitted for clarity.
Ta ble 6. Selected Bon d Len gth s [Å] a n d Bon d
An gles [d eg] of 12
Mo(1)-N(1)
Mo(1)-O(2)
Mo(1)-P(1)
Mo(1)-P(2)
Mo(1)-P(3)
Mo(1)-P(4)
N(1)-O(1)
Mn(1)-C(1)
Mn(1)-C(2)
Mn(1)-C(3)
Mn(1)-C(4)
Mn(1)-C(5)
C(1)-O(2)
C(2)-O(3)
C(3)-O(4)
C(4)-O(5)
C(5)-O(6)
1.761(3)
2.259(3)
2.4506(11)
2.4545(10)
2.4554(10)
2.4595(11)
1.220(4)
1.759(4)
1.831(5)
1.823(4)
1.826(5)
1.830(4)
1.180(5)
1.141(6)
1.154(5)
1.143(6)
1.143(5)
N(1)-Mo(1)-P(1)
N(1)-Mo(1)-P(2)
N(1)-Mo(1)-P(3)
N(1)-Mo(1)-P(4)
P(1)-Mo(1)-P(2)
P(3)-Mo(1)-P(4)
N(1)-Mo(1)-O(2)
C(1)-O(2)-Mo(1)
O(2)-C(1)-Mn(1)
C(1)-Mn(1)-C(2)
C(1)-Mn(1)-C(3)
C(1)-Mn(1)-C(4)
C(1)-Mn(1)-C(5)
C(3)-Mn(1)-C(2)
C(4)-Mn(1)-C(2)
C(3)-Mn(1)-C(5)
C(4)-Mn(1)-C(5)
89.93(12)
92.73(12)
93.54(12)
93.83(12)
80.28(4)
80.73(4)
178.09(14)
159.0(3)
179.2(3)
92.8(2)
115.06(15)
115.8(2)
95.60(19)
88.6(2)
88.3(2)
86.64(15)
89.3(2)
The possibility of a double insertion of 3 into Mn2-
(CO)10, as it was the case for Re2(CO)10, has also been
explored. Reaction of Mn2(CO)10 with up to 3 equiv of 3
was carried out in C7D8 at room temperature and
monitored by NMR spectroscopy. Trace resonances for
a double insertion product could presumably be identi-
fied in the reaction mixture, but the amount of the
product was so small that any attempt of isolation
failed.
in the range 233.9-234.2 ppm are found, confirming the
presence of metal-bound carbonyl groups. The IR spec-
trum of 12 (Nujol mull) shows among others a band at
1580 cm-1 corresponding to a ν(NO) vibration, and five
bands at 2022, 1923, 1908, 1885, and 1746 cm-1 are
assigned to ν(CO) vibrations. This five-band pattern of
the IR spectrum is similar to that of NaMn(CO)5,20
revealing the presence of a Mn(CO)5 fragment. A band
at relatively low wavenumbers (1746 cm-1) provides
evidence for the bridging carbonyl ligand.21 However,
it should be mentioned that by IR spectroscopy alone
the carbonyl coordination mode cannot unambiguously
be distinguished from alternative binding ways.21
To elucidate the structure of complex 12, especially
with respect to the coordination mode of the bridging
carbonyl group, a single-crystal X-ray diffraction study
was carried out. Single crystals suitable for the diffrac-
tion analysis were obtained from diffusion of pentane
into a toluene solution of 12. An ORTEP drawing of 12
is shown in Figure 9. Selected bond distances and angles
are listed in Table 6. The geometry of the Mo(dmpe)2-
(NO) fragment in 12 is very similar to those of all of
the aforementioned structurally characterized com-
plexes. The novel aspect of the structure of 12 is indeed
the coordination mode of the bridging carbonyl group.
It binds to manganese via carbon and to molybdenum
via oxygen, acting as a µ-OC group. This binding feature
remains a rarity22,23 among the versatile bonding modes
of CO groups. The reported complexes, which bear a
Con clu sion s
The molybdenum hydride Mo(dmpe)2(H)(NO) (3) pos-
sesses due to its specific ligand sphere of a tetraphos-
phorus donor substitution pattern and the presence of
the trans influence ligand nitrosyl a strong hydridic
character of the Mo-H bond. This hydride is even more
hydridic than mer-Mo(CO)(H)(NO)(PMe3)3. This was
quantitatively demonstrated with DQCC and bond
ionicity determinations of the corresponding deuterides
obtained from T1min measurements in solution and in
2
solid state from the Pake doublets of static H NMR
spectra. In agreement with its enhanced hydridic prop-
erties, 3 exhibits a high propensity to undergo hydride
transfer reactions, as demonstrated by its reactions with
simple ketones and metal carbonyls, which by insertions
led to alkoxy or formyl compounds. 3 was capable of
reacting even twice with the Re-CO bonds of Re2(CO)10.
The high activity of 3 may be attributed to the effect of
its increased number of strongly σ-donating phosphorus
ligands. This work therefore demonstrates the possibil-
ity of a tuning of the ionic or covalent character of
LnM-H bonds of metal hydrides via appropriate adjust-
ment of the ancillary ligand spheres.
Exp er im en ta l Section
All reactions and manipulations with air-sensitive com-
pounds were performed under an atmosphere of dry nitrogen

Tetraphosphine-Substituted Molybdenum Hydride
Organometallics, Vol. 22, No. 17, 2003 3391
using conventional Schlenk techniques or a glovebox. Solvents
were dried by standard methods and freshly distilled under
nitrogen before use. dmpe26 and trans-Mo(CO)4(NO)(ClAlCl3)27
were prepared following literature procedures. Other reagents
were purchased from Fluka or Aldrich. NMR spectra were
recorded on the following NMR spectrometers: Varian Gemini-
300 instrument, 1H at 300.1 MHz, 13C at 75.4 MHz, 31P at 121.5
MHz, 11B at 96.2 MHz; Bruker DRX-500 instrument, 1H at
500.2 MHz, 13C at 125.8 MHz, 31P at 202.5 MHz, 11B at 160.5
MHz. δ(1H) and δ(13C) relative to SiMe4, δ(31P) relative to 85%
H3PO4, δ(11B) relative to BF3‚OEt2. IR spectra: Biorad FTS-
45 instrument. Mass spectra: Finnigan-MAT-8400 spectrom-
eter; FAB spectra in 3-nitrobenzyl alcohol matrix. Elemental
analyses: Leco CHN(S)-932 instrument.
product of 3 as a yellow solid. Yield: 0.16 g (92%). IR (cm-1
THF): 1557 (NO). H NMR (C6D6): 1.47 (s, 12H, PMe), 1.27
,
1
2
(s, 12H, PMe′), 1.37 (m, 8H, PCH2), -4.58 (quint, br, J HP
)
)
1
29 Hz, 1H, MoH). 13C{1H} NMR (C6D6): 32.1 (quint, J CP
1
11 Hz, PCH2), 22.9 (quint, J CP ) 6.6 Hz, PMe), 18.0 (quint,
1J CP ) 4.4 Hz, PMe′). 31P{1H} NMR (C6D6): 44.2 (s). EI-MS:
427 (86, M+), 412 (16, [M+ - CH3]), 397 (13, [M+ - NO]), 337
(15, [M+ - NO - 4Me]), 277 (11, [M+ - dmpe]). Anal. Calcd
for C12H33MoNOP4: C 33.73, H 7.80, N 3.28. Found: C 34.10,
H 7.66, N 3.00.
tr a n s-Mo(d m p e)2(D)(NO) (3a ). 3a was prepared from 2a
in a procedure analogous to that for 3. 31P{1H} NMR (C7D8):
2
44.3 (t, J PD ) 5 Hz). 2H NMR (C7H8): -4.72 (m, MoD). IR
(cm-1, THF): 1542 (NO).
tr a n s-Mo(Cl)(d m p e)2(NO) (1). A 40 mL autoclave was
charged under nitrogen with a mixture of 0.84 g (2.06 mmol)
of trans-Mo(CO)4(NO)(ClAlCl3) and 1.0 g (6.66 mmol) of dmpe
in 25 mL of THF and then heated to 160 °C. During this time
the produced CO was released periodically from the autoclave
under N2 to facilitate the reaction. After 8 days the mixture
was cooled to room temperature and then filtered. The filtrate
was dried in vacuo, and the remaining residue was extracted
with Et2O. Concentration and chilling of the combined solu-
tions to -30 °C afforded yellow crystals of 1. Yield: 0.80 g
m er -Mo(CO)(D)(NO)(P Me3)3 (4). At first the borodeu-
teride mer-Mo(η1-BD4)(CO)(NO)(PMe3)3 was prepared in a
procedure analogous to that for mer-Mo(η1-BH4)(CO)(NO)-
(PMe3)3 except that NaBD4 and LiCl were used as a substitute
for LiBD4.8 Then 4 was prepared from the borodeuteride in a
procedure analogous to that for mer-Mo(CO)(H)(NO)(PMe3)3.8
2
2
31P{1H} NMR (C7D8): -3.80 (dt, J PP ) 29 Hz, J PD ) 5 Hz, 2
PMe3 trans), -11.4 (tt, 2J PP ) 29 Hz, 2J PD ) 4 Hz, PMe3 trans
2
CO). H NMR (C7H8): -1.90 (m, br, MoD). IR (cm-1, hexane):
1916 (CO), 1597 (NO).
1
(84%). IR (cm-1, THF): 1553 (NO). H NMR (C6D6): 1.35 (s,
tr a n s-Mo(d m p e)2(NO)(OCHP h 2) (5). A mixture of 0.0210
g (0.049 mmol) of 3 and 0.0095 g (0.052 mmol) of benzophenone
was dissolved in ca. 0.7 mL of C7D8. The reaction was
monitored by 1H NMR. After 2 h the reaction was complete.
The solvent was removed in vacuo, and the remaining residue
was extracted with pentane. The combined solutions were
concentrated and cooled to -30 °C to give yellow crystals of 5.
Yield: 0.265 g (89%). IR (cm-1, THF): 1528 (NO). 1H NMR
(C6D6): 7.32 (m, 4H, Ph), 7.10 (m, 4H, Ph), 6.95 (m, 2H, Ph),
5.03 (s, 1H, OCH), 1.34 (s, 12H, PMe), 1.19 (s, 12H, PMe′),
1.26 (m, 8H, PCH2). 13C{1H} NMR (C6D6): 153.9, 127.7, 126.4,
br, 24H, PMe), 1.45 (m, 4H, PCH2), 1.24 (m, 4H, PCH2′). 13C-
1
{1H} NMR (C6D6): 29.9 (quint, J CP ) 10 Hz, PCH2), 14.9
(quint, 1J CP ) 5.3 Hz, PMe), 14.8 (quint, 1J CP ) 5.3 Hz, PMe′).
31P{1H} NMR (C6D6): 35.4 (s). EI-MS: 462 (48, M+), 431 (22,
[M+ - NO]), 371 (24, [M+ - NO - 4Me3]), 312 (44, [M+
-
-
dmpe]), 282 (16, [M+ - dmpe - NO]). Anal. Calcd for C12H32
ClMoNOP4: C 31.21, H 7.00, N 3.03. Found: C 31.54, H 6.93,
N 3.00.
tr a n s-Mo(η1-BH4)(d m p e)2(NO) (2). A 0.16 g (0.35 mmol)
sample of 1 was dissolved in 20 mL of Et2O, and then 0.04 g
(1.84 mmol) of LiBH4 was added. The resulting mixture was
stirred at room temperature for 4 days, then the solvent was
removed in vacuo. The residue was extracted with toluene
until the solution remained colorless. The remaining solid was
redissolved in Et2O and cooled to -30 °C. After one night the
Et2O was removed again in vacuo and the residue extracted
with toluene. This procedure was repeated four times. Com-
bination of the extracts and removal of the toluene gave a
yellow solid. Recrystallization from Et2O at -30 °C afforded
3
125.5 (4s, Ph), 85.3 (quint, J CP ) 3.9 Hz, OCH), 30.2 (quint,
1
1J CP ) 9.5 Hz, PCH2), 16.4 (quint, J CP ) 4.2 Hz, PMe), 15.3
1
(quint, J CP ) 5.3 Hz, PMe′). 31P{1H} NMR (C6D6): 31.9 (s).
EI-MS: 610 (65, M+), 459 (100, [M+ - dmpe]), 426 (14, [M+
-
Ph2CHO]), 396 (13, [M+ - Ph2CHO - NO]). Anal. Calcd for
25H43MoNO2P4: C 49.26, H 7.13, N 2.30. Found: C 49.24, H
C
7.22, N 2.31.
tr a n s-Mo(d m p e)2(NO)[OCH(CH3)(P h )] (6). To a solution
of 0.023 g (0.054 mmol) of 3 in ca. 0.7 mL of C7D8 in an NMR
tube was added 6.5 µL (0.056 mmol) of acetophenone. The
reaction was monitored at room temperature by 1H NMR. After
1.5 h the reaction was complete. Then the solvent was removed
in vacuo and the remaining residue recrystallized from pen-
tane at -30 °C to afford 6 as a yellow solid. Yield: 0.025 g
analytically pure crystals of 2. Yield: 0.12 g (80%). IR (cm-1
,
1
THF): 1567 (NO). H NMR (C6D6): 1.40 (s, 12H, PMe), 1.26
(s, 12H, PMe′), 1.47 (m, 4H, PCH2), 1.19 (m, 4H, PCH2′), -2.26
(quart, br, 1J HB ) 81 Hz, 4H, BH4). 13C{1H} NMR (C6D6): 30.0
(quint, 1J CP ) 10 Hz, PCH2), 16.5 (quint, 1J CP ) 6.0 Hz, PMe),
1
15.1 (quint, J CP ) 5.4 Hz, PMe′). 11B NMR (C6D6): -42.1
(85%). IR (cm-1, THF): 1524 (NO). 1H NMR (C6D6): 7.26-
1
(quint, J BH ) 81 Hz). 31P{1H} NMR (C6D6): 36.2 (s). EI-MS:
3
7.15 (m, 4H, Ph), 7.10-7.05 (m, 1H, Ph), 4.14 (quart, J HH
)
441 (11, M+), 427 (86, [M+ - BH3]), 411 (21, [M+ - NO]), Anal.
Calcd for C12H36BMoNOP4: C 32.67, H 8.24, N 3.18. Found:
C 32.88, H 8.21, N 3.19.
6 Hz, 1H, OCH), 1.37 (m, 12H, PMe), 1.30 (m, 6H, PMe′), 1.22
3
(m, 6H, PMe′), 1.34 (m, 8H, PCH2), 1.04 (d, J HH ) 6 Hz, 3H,
-CH3). 13C{1H} NMR (C6D6): 155.2, 127.5, 125.9, 125.4 (4s,
tr a n s-Mo(η1-BD4)(d m p e)2(NO) (2a ). 2a was prepared in
a procedure analogous to that for 2 except that NaBD4 and
LiCl were used as a substitute for LiBD4 in the conversion of
chloride 1. 31P{1H} NMR (C6D6): 36.3 (t, 2J PD ) 5 Hz). 2H NMR
(C6H6): -2.30 (m, br, DBD3).
tr a n s-Mo(d m p e)2(H)(NO) (3). A 0.18 g (0.41 mmol) sample
of 2 and 0.36 g (3.24 mmol) of quinuclidine were dissolved in
15 mL of toluene. The resulting solution was stirred at room
temperature for 48 h, then the solvent was removed in vacuo.
The remaining residue was extracted with pentane. Removal
of pentane at room temperature and subsequent sublimation
of excess quinuclidine at 60 °C for 24 h in vacuo afforded the
3
Ph), 77.5 (quint, J CP ) 3.5 Hz, OCH), 31.8 (s, br, PCH2), 16.0
(m, PMe), 15.7 (m, PMe′), 15.3 (m, PMe). 31P{1H} NMR
(C6D6): 32.4 (m). EI-MS: 547 (88, M+), 427 (32, [M+
-
-
MePhCHO]), 397 (100, [M+ - dmpe]). Anal. Calcd for C20H41
MoNO2P4: C 43.88, H 7.56, N 2.56. Found: C 44.07, H 7.36,
N 2.62.
tr a n s-Mo(d m p e)2(NO)[OCH(CH3)2] (7). A 4.4 µL (0.06
mmol) sample of acetone was added to a solution of 0.025 g
(0.059 mmol) of 3 in ca. 0.7 mL of C7D8 in an NMR tube. The
mixture was monitored by 1H NMR. After 3 h the reaction was
complete. The solvent was removed in vacuo and the residue
was extracted with pentane. Concentration and chilling to -30
°C of the extracts produced a yellow solid of 7. Yield: 0.023 g
(80%). IR (cm-1, THF): 1520 (NO). 1H NMR (C6D6): 3.25 (hept,
3J HH ) 6 Hz, 1H, OCH), 1.40 (s, br, 12H, PMe), 1.29 (s, br,
(26) Burt, R. J .; Chatt, J .; Hussain, W.; Leigh, G. J . J . Organomet.
Chem. 1979, 182, 203.
(27) Seyferth, K.; Taube, R. J . Organomet. Chem. 1982, 229, 275;
Cheng, T. Y.; Southern T. S.; Hillhouse, G. L. Organometallics 1997,
16, 2335.
3
12H, PMe′), 1.35 (m, 8H, PCH2), 0.87 (d, J HH ) 6 Hz, 6H,
-CH3). 13C{1H} NMR (C6D6): 69.3 (quint, 3J CP ) 3.6 Hz, OCH),

3392 Organometallics, Vol. 22, No. 17, 2003
Ta ble 7. Cr ysta llogr a p h ic Da ta a n d Str u ctu r e Refin em en t P a r a m eter s for 1, 2, a n d 8
Liang et al.
1
2
8
formula
color
C
12H32ClMoNOP4
C
12H36BMoNOP4
C17H33FeMoNO6P4
orange
yellow
yellow
cryst dimens (mm)
temp (K)
cryst syst
space group (No.)
a (Å)
b (Å)
c (Å)
R (deg)
â (deg)
γ (deg)
V (Å3)
0.40 × 0.33 × 0.30
0.49 × 0.42 × 0.30
0.44 × 0.21 × 0.20
173(2)
173(2)
183(2)
monoclinic
P21/n (14)
9.5217(8)
11.3764(7)
10.0280(8)
90
92.438(10)
90
1085.28(14)
2
monoclinic
P21/n (14)
8.4970(7)
13.2450(10)
9.7498(8)
90
94.501(10)
90
1093.89(15)
2
orthorhombic
Cmc21 (36)
14.9570(10)
15.3181(11)
12.0282(9)
90
90
90
2755.8(3)
4
Z
fw
461.66
1.413
1.019
476
441.05
1.339
0.888
460
623.11
1.502
1.243
1272
d(calcd) (g cm-3
abs coeff (mm-1
F(000)
)
)
2θ scan range (deg)
no. of unique data
no. of data obsd [I > 2σ(I)]
abs corr
6.80 < 2θ < 60.48
6.86 < 2θ < 60.72
7.62 < 2θ < 60.58
3081
3026
3918
2623
2582
3531
numerical
Patterson
110
2.69, 5.78
2.18, 5.53
1.03
numerical
Patterson
108
5.12, 12.79
4.26, 12.25
1.21
numerical
Patterson
155
4.48, 11.66
3.51, 9.17
1.125
solution method
no. of params refined
R, wR2 (%) all data
R1, wR2 (obsd) (%)a
goodness-of-fit
R1 ) ∑(Fo - Fc)/∑Fo; I > 2σ(I); wR2 ) {∑w(Fo - Fc2)2/∑w(Fo2)2}1/2
.
a
2
30.4 (quint,1J CP ) 9.8 Hz, PCH2), 29.9 (s, CH3), 15.4 (m, PMe).
31P{1H} NMR (C6D6): 32.8 (s). EI-MS: 485 (70, M+), 426 (28,
[M+ - Me2CHO]), 396 (28, [M+ - Me2CHO - NO]), 335 (100,
[M+ - dmpe]). Anal. Calcd for C15H39MoNO2P4: C 37.12, H
8.12, N 2.89. Found: C 37.23, H 8.44, N 2.96.
(ON)(d m p e)2Mo(µ-OCH )R e2(CO)8(µ-CH O)Mo(d m p e)2-
(NO) (10). 3 (0.0375 g, 0.088 mmol) and Re2(CO)10 (0.0143 g,
0.022 mmol) were treated in toluene (ca. 2 mL). In a few
minutes the Re2(CO)10 dissolved completely and a yellow
solution was obtained. Diffusion of pentane into this solution
afforded yellow crystals. IR (cm-1, THF): 2048, 1996, 1881
(Re2(CO)8), 1565(NO). 1H NMR (C7D8): 14.66 (s, 2H, OCH),
1.27 (m, 16H, PCH2), 1.14 (s,br, 48H, PMe). 13C{1H} NMR
(C7D8): 298.9 (m, OCH), 207.1, 200.8 (2s, Re2(CO)8), 29.9
tr a n s-Mo(d m p e)2(NO)[(µ-OCH)F e(CO)4] (8). A 0.028 g
(0.066 mmol) sample of 3 was dissolved in ca. 0.7 mL of C7D8
in an NMR tube, and 9.0 µL (0.068 mmol) of iron pentacar-
bonyl was added. In a few minutes some crystals precipitated
from the solution and the reaction was complete (1H NMR
monitoring). The solvent was removed in vacuo, and the
remaining residue was dissolved in ca. 0.5 mL of THF.
Diffusion of pentane into the THF solution afforded 8 as orange
crystals. Yield: 0.033 g (81%). IR (cm-1, THF): 2032, 1949,
1918 (Fe(CO)4), 1570 (NO). 1H NMR (C6D6): 13.52 (m, 1H,
OCH), 1.23 (m, 8H, PCH2), 1.14 (s, br, 12H, PMe), 1.11 (s, br,
1
(quint,1J CP ) 10 Hz, PCH2), 14.9 (quint, J CP ) 5 Hz, PMe),
1
14.7 (quint, J CP ) 5 Hz, PMe′). 31P{1H} NMR (C7D8): 36.5
(s). Anal. Calcd for C34H66Mo2N2O12P8Re2: C 27.10, H 4.42, N
1.86. Found: C 32.05, H 4.68, N 1.75. An analytically pure
sample could not be obtained. But crystals suitable for X-ray
diffraction study were selected from the mixture.
tr a n s-Mo(d m p e)2(NO)[(µ-OC)Mn (CO)4] (12). A 0.018 g
(0.042 mmol) sample of 3 was dissolved in ca. 0.7 mL of
C7D8. To this solution was added 0.017 g (0.044 mmol) of
dimanganese decacarbonyl. The reaction was monitored by
1H NMR. After 2 days the solvent was removed and the
residue was dissolved in toluene. Diffusion of pentane into the
toluene solution afforded yellow crystals of 12. Yield: 0.019 g
(73%).
3
12H, PMe′). 13C{1H} NMR (C6D6): 299.3 (quint, J CP ) 4 Hz,
-OCH-), 218.5 (s, Fe(CO)4), 29.2 (quint, 1J CP ) 10 Hz, PCH2),
14.3 (m, PMe). 31P{1H} NMR (C6D6): 35.3 (s). EI-MS: 473 (40,
[M+ - dmpe]), 426 (83, [M+ - Fe(CO)4CHO]), 411 (31, [M+
-
Fe(CO)4CHO - CH3]), 396 (18, [M+ - Fe(CO)4CHO - NO]).
Anal. Calcd for C17H33FeMoNO6P4: C 32.76, H 5.35, N 2.25.
Found: C 33.06, H 5.52, N 2.27.
tr a n s-Mo(d m p e)2(NO)[(µ-OCH)Re2(CO)9] (9). To a solu-
tion of 0.023 g (0.054 mmol) of 3 in ca. 0.7 mL of C7D8 was
added 0.035 g (0.054 mmol) of dirhenium decacarbonyl. In a
few minutes the Re2(CO)10 dissolved and the reaction was
complete (NMR monitoring). The solvent was removed in
vacuo, and the remaining residue was extracted with Et2O.
Concentration and cooling to -30 °C of the extracts gave
orange crystals of 9. Yield: 0.050 g (86%). IR (cm-1, THF):
2094, 2031, 2009, 1981, 1952, 1939, 1911 (Re2(CO)9), 1571
(NO). 1H NMR (C7D8): 14.57 (s, 1H, OCH), 1.27 (m, 8H, PCH2),
1.10 (s, br, 24H, PMe). 13C{1H} NMR (C7D8): 298.4 (m, OCH),
Alternative method: to a solution of 0.021 g (0.049 mmol)
of 3 in ca. 0.7 mL of C7D8 was added 0.0096 g (0.049 mmol) of
manganese pentacarbonyl hydride, which was prepared ac-
cording to a literature procedure.28 H2 gas liberated im-
mediately and in a few minutes the reaction was complete
(NMR monitoring). The product was isolated by the procedure
described above in a yield of 90% (0.028 g). IR (cm-1, Nujol):
2022(w), 1923(m), 1908(m), 1885(s) (Mn(CO)4), 1746(s) (Mn-
1
CO-Mo), 1580(s) (NO). H NMR (C6D6): 1.21 (m, 4H, PCH2),
1.02 (m, 4H, PCH2′), 1.16 (s, br, 12H, PMe), 1.07 (s, br, 12H,
PMe′). 13C{1H} NMR (C6D6): 234.1 (m, MnCO), 29.1 (quint,
1J CP ) 10 Hz, PCH2), 14.3 (m, PMe). 31P{1H} NMR (C6D6): 36.0
(s). Anal. Calcd for C17H32MnMoNO6P4: C 32.86, H 5.20, N
2.26. Found: C 33.00, H 4.86, N 2.26.
1
200.9, 196.2, 192.2 (3s, Re2(CO)9), 29.6 (quint, J CP ) 10 Hz,
1
1
PCH2), 14.6 (quint, J CP ) 5.4 Hz, PMe), 14.4 (quint, J CP
)
5.4 Hz, PMe′). 31P{1H} NMR (C7D8): 36.0 (s). EI-MS: 749 (28,
[M+ - 2dmpe - NO]), 662 (50, [M+ - H - Re(CO)5 - NO -
4CH3]), 632 (32, [M+ - H - Re(CO)5 - NO - 6CH3]), 602 (18,
[M+ - H - Re(CO)5 - dmpe]), 422 (46, [M+ - H - Re(CO)5 -
2dmpe - NO]). Anal. Calcd for C22H33MoNO11P4Re2: C 24.47,
H 3.09, N 1.30. Found: C 24.77, H 3.08, N 1.18.
X-r a y Cr ysta l Str u ctu r e An a lyses. The intensity diffrac-
tion data were collected at 173(2) K (1, 2) and 183(2) K (8, 9,
(28) Sanders, J . R. J . Chem. Soc., Dalton Trans. 1973, 748; 1975,
2340.

Tetraphosphine-Substituted Molybdenum Hydride
Organometallics, Vol. 22, No. 17, 2003 3393
Ta ble 8. Cr ysta llogr a p h ic Da ta a n d Str u ctu r e Refin em en t P a r a m eter s for 9, 10, a n d 12
9
10
12
formula
color
cryst dimens (mm)
temp (K)
cryst syst
space group (No.)
a (Å)
b (Å)
c (Å)
R (deg)
â (deg)
γ (deg)
V (Å3)
C
22H33MoNO11P4Re2
C
41H74Mo2N2O12P8Re2
C
17H32MnMoNO6P4
orange
yellow
yellow
0.34 × 0.33 × 0.20
0.26 × 0.24 × 0.16
0.33 × 0.26 × 0.14
183(2)
183(2)
183(2)
monoclinic
P21 (4)
10.7609(9)
12.4912(11)
12.8377(11)
90
93.193(10)
90
1722.9(3)
2
orthorhombic
Fdd2 (43)
34.9624(16)
65.681(3)
10.5624(6)
90
90
90
24255(2)
16
triclinic
P1h (2)
9.4800(8)
9.7992(9)
16.3841(15)
105.481(10)
95.446(11)
109.324(10)
1355.8(2)
2
Z
fw
1079.71
2.081
7.602
1599.06
1.752
4.646
621.20
1.522
1.193
632
d(calcd) (g cm-3
abs coeff (mm-1
F(000)
)
)
1024
12544
2θ scan range (deg)
no. of unique data
no. of data obsd [I > 2σ(I)]
abs corr
5.82 < 2θ < 60.84
4.08 < 2θ < 47.36
5.60 < 2θ < 60.54
10 198
9113
7353
8034
8635
5864
numerical
Patterson
334
7.72, 16.10
6.00, 15.02
1.063
numerical
Patterson
622
3.51, 8.26
3.34, 8.20
1.106
numerical
Patterson
279
5.45, 14.13
3.98, 11.54
1.149
solution method
no. of params refined
R, wR2 (%) all data
R1, wR2 (obsd) (%)a
goodness-of-fit
R1 ) ∑(Fo - Fc)/∑Fo; I > 2σ(I); wR2 ) {∑w(Fo - Fc2)2/∑w(Fo2)2}1/2
.
a
2
10, 12) using an imaging plate detector system (Stoe IPDS)
with graphite-monochromated Mo KR radiation. A total of 150,
129, 167, 120, 260, and 167 images were exposed at constant
times of 1.50, 1.80, 2.50, 3.50, 3.00, and 3.00 min/image for
compounds 1, 2, 8, 9, 10, and 12, respectively. The crystal-to-
image distances were set to 50 mm, except for compound 10,
which had a necessary large distance of 82 mm. The corre-
sponding θmax values were 30.24°, 30.36°, 30.29°, 30.42°, 23.68°,
and30.27°, respectively. φ-oscillation (10, 12) or rotation scan
modes (1, 2, 8, 9) were selected for the φ increments of 1.2°,1.4°,
1.2°, 1.5°, 0.7°, and1.2° per exposure in each case. Total
exposure times for the six compounds were 14, 13, 19, 15, 31,
and 20 h in the order of the complexes given above. After
integrations and corrections for Lorentz and polarization
effects, a total of 8000 reflections were selected out of the whole
limiting sphere for the cell parameter refinements. A total of
11 098, 11 328, 16 263, 14 313, 27 084, and 15 938 reflections
were collected, of which 3081, 3026, 3918, 10198, 9113, and
7353 reflections were unique (Rint ) 4.54%, 3.08%, 3.07%,
7.66%, 3.68%, and 2.98%); data reduction and numerical
absorption correction used 14, 15, 15, 15, 13, and 9 indexed
crystal faces.29
using Flack’s x-parameter refinement.32 The absolute structure
parameter x for 8, 9, and 10 was -0.01(3), 0.520(17), and
0.224(5), respectively. Merohedrical twinning was observed for
9 and 10 with an appoximate twin ratio of 1:1 and 1:4,
respectively. The X-ray data collections and the processing
parameters are given in Table 7 and Table 8.
Ackn owledgm en t. Financial support from the Swiss
National Science Foundation is gratefully acknowl-
edged.
Su p p or tin g In for m a tion Ava ila ble: Tables of crystal
data and structure refinement parameters, atomic coordinates,
bond lengths, bond angles, anisotropic displacement param-
eters, and hydrogen coordinates of 1, 2, 8, 9, 10, and 12.
Additional IR and NMR spectra of 10. This material is
available free of charge via the Internet at http://pubs.acs.org.
OM021032T
(29) Stoe IPDS software for data collection, cell refinement and data
reduction, Version 2.87-2.92 (the latter used for 5); Stoe & Cie:
Darmstadt, Germany, 1997-1999.
(30) SHELXS-97: Sheldrick, G. M. Acta Crystallogr. 1990, 46A, 467.
(31) SHELXL-97: Sheldrick, G. M. Program for the Refinement of
Crystal Structures; University of Go¨ttingen: Germany, 1997.
(32) (a) Flack, H. D. Acta Crystallogr. 1983, A39, 876. (b) Flack, H.
D.; Bernardinelli, G. Acta Crystallogr. 1999, A55, 908.
The structures were solved by the Patterson method using
the Program SHELXS-97,30 and they were refined with
SHELXL-97.31 The absolute structure was determined by