Reaction of [Cp2(CO)3Mo2(μ-η2-P 2)(PPh2)]- with the cumulenes 3-ClC6H4NCO, PhNCS, and CS2 and with Michael acceptors: Synthesis and reactivity

Article abstract of DOI:10.1021/om990729k

Deprotonation of the complex [Cp₂(CO)₃Mo₂(μ-η-P₂)(PPh ₂H)] (1) yields the anion [Cp₂(CO)₃-Mo₂(μ-η²-P ₂)(PPh₂)]^- (2). Reacti

Full text of DOI:10.1021/om990729k

984
Organometallics 2000, 19, 984-993
Rea ction of [Cp 2(CO)3Mo2(µ-η2-P 2)(P P h 2)]- w ith th e
Cu m u len es 3-ClC6H4NCO, P h NCS, a n d CS2 a n d w ith
Mich a el Accep tor s: Syn th esis a n d Rea ctivity of
[Cp 2(CO)3Mo2(µ-η3-P h 2P C(H)SP 2S)], a Com p lex
Con ta in in g a n Un u su a l CSP 2S F ive-Mem ber ed Rin g
J ohn E. Davies, Neil Feeder, Martin J . Mays,* Peter K. Tompkin, and
Anthony D. Woods
Department of Chemistry, Lensfield Road, Cambridge CB2 1EW, U.K.
Received September 16, 1999
Deprotonation of the complex [Cp2(CO)3Mo2(µ-η2-P2)(PPh2H)] (1) yields the anion [Cp2(CO)3-
Mo2(µ-η2-P2)(PPh2)]- (2). Reaction of 2 with cumulenes such as 3-ClC6H4NCO and PhNCS
leads, after reprotonation, to the simple addition products [Cp2(CO)3Mo2(µ-η2-P2){PPh2C(d
X)NHR}] (R ) 3-ClPh, X ) O, 4a ; R ) Ph, X ) S, 4b). Reaction of 2 with the Michael acceptors
H2CdC(H)R gives the related products [Cp2(CO)3Mo2(µ-η2-P2)(PPh2C2H4R)] (R ) COOMe,
5a ; R ) CN, 5b; R ) COMe, 5c). In contrast, reaction of 2 with CS2 followed by HBF4 yields
the complex [Cp2(CO)3Mo2(µ-η3-Ph2PC(H)SP2S)] (3), which has an unprecedented bridging
t
ligand containing a CSP2S five-membered ring. Reaction of 3 with BuLi followed by MeI
yields [Cp2(CO)3Mo2(µ-η2-P2){PPh2C(S)SMe}] (6), in which ring scission and re-formation of
the tetrahedral Mo2P2 core present in complex 1 has taken place. Reaction of 3 with metal
carbonyls can also lead to re-formation of the Mo2P2 moiety. The crystal structures of five of
the new complexes have been determined.
In tr od u ction
anion [Cp2(CO)3Mo2(µ-η2-P2)(PPh2)]- (2) with cumulenes
other than CS2 and with Michael accceptors. Addition-
ally, we report reactions of the complex [Cp2(CO)3Mo2(µ-
η3-Ph2PC(H)SP2S)] (3) with metal carbonyls and of
deprotonated 3 with MeI and HBF4.
The deprotonation of a secondary phosphine within
the coordination sphere of a metal complex, followed by
subsequent reaction of the resulting anion with a wide
variety of electrophiles, can be used to generate novel
phosphine ligands, including stereogenic phosphines
which are not readily obtainable by other means.1,2 We
recently reported in a preliminary communication that
this approach leads in the case of the reaction of
[Cp2(CO)3Mo2(µ-η2-P2)(PPh2)]- (2) with CS2 to the for-
mation of [Cp2(CO)3Mo2(µ-η3-Ph2PC(H)SP2S)] (3), in
which unexpected activation of the bridging diphospho-
rus moiety present in 2 has occurred.3 This reaction is
particularly interesting, as the coordinated P2 unit in
dimetallic complexes is generally very unreactive, previ-
ously documented reactions simply involving the dona-
tion of one or both of the uncoordinated phosphorus lone
pairs of the P2 unit to Lewis acids.4
Resu lts a n d Discu ssion
Rea ction of th e An ion [Cp 2(CO)3Mo2(µ-η2-P 2)-
(P P h 2)]- (2) w ith Electr op h iles. Deprotonation of
[Cp2(CO)3Mo2(µ-η2-P2)(PPh2H)] with DBU (DBU ) 1,8-
diazabicyclo[5.4.0]undec-7-ene) proceeds smoothly under
mild conditions to yield the anion [Cp2(CO)3Mo2(µ-η2-
P2)(PPh2)]- (2). Stirring a solution of 2 in dichloro-
methane with an excess of the cumulenes 3-ClC6H4NCO
and PhNCS (1.5-2 equiv) for 2 h at room temperature
followed by reprotonation with HBF4 gives, in addition
to unreacted starting material, the simple addition
products [Cp2(CO)3Mo2(µ-η2-P2)PPh2C(dX)NHR] (R )
3-ClPh, X ) O, 4a ; R ) Ph, X ) S, 4b) in high yield
(80-90%) (Scheme 1). Reaction of 2 with the aliphatic
In this paper we report the results of attempts to
activate a P2 bridging ligand via the reaction of the
t
isothiocyanate BuNCS, however, yielded no new prod-
* To whom correspondence should be addressed. E-mail: mjm14@
cus.cam.ac.uk.
ucts. A similar difference in the reactivities of aryl and
alkyl isothiocyanates has been previously reported by
Lin et al.,5 who reported that the reaction of [W(CO)5-
PPh2]- with RNCS only proceeded when R ) aryl. This
(1) (a) Malisch, W.; Rehmann, F. J .; J ehle, H.; Reising, J . J .
Organomet. Chem. 1998, 570, 107. (b) Malisch, W.; Rehmann, F. J .;
J ehle, H.; Reising Gunzelmann, N. Eur. J . Inorg. Chem. 1998, 1589.
(2) See for example: (a) Weller, F.; Pertz. W. J . Chem. Soc., Chem.
Commun. 1995, 1049. (b) Yih, K. H.; Cheng, M. C.; Wang, Y.; Lin, Y.
C. J . Chem. Soc., Dalton Trans. 1995, 1305. (c) Gal, A. W.; Gosselink,
J . W.; Vollenbroek, F. A. J . Organomet. Chem. 1977, 142, 357. (d)
Pietrusiewcz, K. M.; Zablocka, M. Chem. Rev. 1994, 94, 1375. (e)
Kagan, H. B.; Sasaki, M. In The Chemistry of Organophosphorus
Compounds; Patai, S., Rappoport, Z., Eds.; Wiley: New York, 1990;
Vol. 1.
(4) (a) Scherer, O. J .; Sitzman, H.; Wolmerha¨user, G. Angew. Chem.,
Int. Ed. Engl. 1984, 23, 968. (b) Lang, H.; Znolsai, L.; Hunter, G.
Angew. Chem., Int. Ed. Engl. 1983, 22, 976. (c) Visi-Orosz, A.; Payli,
G.; Marko, L.; Boese, R.; Schmid, G. J . Organomet. Chem. 1985, 288,
179. (d) Goh, L. Y.; Wong, R. C. S.; Mak, T. W. C. J . Organomet. Chem.
1989, 373, 71.
(3) Davies, J . E.; Mays, M. J .; Raithby, P. R.; Shields, G. P.;
Tompkin, P. K. J . Chem. Soc., Chem. Commun. 1996, 2051.
(5) Yih, K. H.; Cheng, M. C.; Wang, Y.; Lin, Y. C. Organometallics
1998, 17, 513.
10.1021/om990729k CCC: $19.00 © 2000 American Chemical Society
Publication on Web 02/17/2000

A Complex Containing a CSP2S Five-Membered Ring
Organometallics, Vol. 19, No. 6, 2000 985
Sch em e 1
difference may be due to the electron-withdrawing aryl
group on the nitrogen atom increasing the partial
positive charge on the carbon atom of the NCS group,
hence making it more susceptible to nucleophilic attack.
In contrast to the outcome of the reactions with
isocyanate and isothiocyanate, reaction of 2 with CS2
does not lead to the formation of an analogue of the
pendant thiolatophosphine [LnMPPh2C(S)SH], reported
by Lin et al. as a product of the reaction of [W(CO)5-
PPh2]- and CS2.2b Instead, the complex [Cp2(CO)3Mo2(µ-
η3-Ph2PC(H)SP2S)] (3) is obtained. The structure of 3
has already been reported by us in a preliminary
communication.3
It is unclear why the reactions of 2 with isocyanate
and isothiocyanate do not lead to the formation of
products similar to 3. A possible explanation is based
upon the relative stabilities of the anionic adducts
formed in the two cases. Reaction of 2 with either an
isocyanate or isothiocyanate presumably leads initially
to a coordinated phosphine of the type [Ph2PC(X)NPh]-
(X ) O, S), where the negative charge is formally on
the amide nitrogen atom. In this coordinated phosphine
the negative charge can be delocalized over both the
nitrogen-bound phenyl group and the C(X) group. In
contrast, in the case of reaction with CS2 a less stable
anionic adduct is formed in which the negative charge
is localized on the cumulene moiety, which is then a
good nucleophile and attacks the µ-η2-P2 unit to give
the CSP2S ring.
An additional factor favoring ring formation in the
reaction of 2 with CS2 as compared to RNCS or RNCO
may be that the CSP2S ring is more stable than the
CXP2N ring, which would be formed if the RNCX
adducts were to cyclize. Thus, the C-S-P bond angle
of 94.7° in complex 3 suggests that a great deal of strain
is present in the ring. This ring strain would be
enhanced in the hypothetical CXP2N ring due to the
smaller size of the N heteroatom. Hence, this ring does
not form, and on reprotonation of the RNCX adducts,
complexes containing a pendant phosphine of the type
reported by Ambrosius et al. are obtained,6 in which the
Mo2P2 core present in 1 and 2 remains unaltered.
Clearly, the first step in all reactions of 2 with the
unsaturated species studied here is nucleophilic attack
of the phosphido anion on the organic electrophile, the
resulting pendant phosphine then bearing a negative
charge which, in favorable cases, can attack the P2 unit.
To determine whether attack on the P2 unit by a
pendant phosphine would be facilitated if the negative
(6) Ambrosius, H. P. M.; Van der Linden, A. H. I. M.; Steggerda, J .
J . J . Organomet. Chem. 1980, 204, 211.

986 Organometallics, Vol. 19, No. 6, 2000
Davies et al.
F igu r e 1. Molecular structures of (left) [Cp2(CO)3Mo2(µ-η2-P2)(PPh2C2H4COOMe)] (5a ) and (right) [Cp2(CO)3Mo2(µ-η2-
P2)(PPh2C2H4CN)] (5b). Thermal ellipsoids are shown at the 30% probability level.
Ta ble 1. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for [Cp 2(CO)3Mo2(µ-η2-P 2)(P P h 2C2H4COOMe)]
(5a ) a n d [Cp 2(CO)3Mo2(µ-η2-P 2)(P P h 2C2H4CN)] (5b)
charge on the pendant ligand lay further away from the
phosphine phosphorus atom than in the anions gener-
ated by reaction with RNCO and RNCS, the reactions
of complex 2 with Michael acceptors such as MVK (MVK
) methyl vinyl ketone) were investigated. In the pre-
sumed ionic intermediate formed on reaction of 2 with
Michael acceptors (Scheme 1), the charge on the result-
ant pendant phosphine moiety lies either on the carbon
atom â to the metal or on the heteroatom of the R group
and is hence more distant from the phosphine phospho-
rus atom than in the pendant phosphines derived from
reaction of 2 with RNCX. Reaction of a solution of 2 in
dichloromethane with the classic Michael acceptors
H2CdC(H)R (R ) COOMe, COMe, CN) proceeds
smoothly at room temperature, but the resulting pen-
dant phosphine ligand shows no tendency to attack the
η2-P2 unit, even in refluxing THF, and, after reproto-
nation with HBF4, the complexes [Cp2(CO)3Mo2(µ-η2-
P2)(PPh2C2H4R)] (R ) COOMe, 5a ; R ) CN, 5b; R )
COMe, 5c) were obtained in near-quantitative yield
(Scheme 1).
5a
5b
Mo(1)-Mo(2)
Mo(1)-P(1)
Mo(1)-P(2)
Mo(1)-P(3)
Mo(2)-P(1)
Mo(2)-P(2)
P(1)-P(2)
3.0240(9) Mo(1)-Mo(2)
3.0334(7)
2.464(1)
2.529(1)
2.462(1)
2.567(1)
2.451(1)
2.085(1)
2.527(2)
2.463(2)
2.465(2)
2.455(2)
2.575(2)
2.077(2)
Mo(1)-P(1)
Mo(1)-P(2)
Mo(1)-P(3)
Mo(2)-P(1)
Mo(2)-P(2)
P(1)-P(2)
P(1)-Mo(1)-P(2)
P(2)-Mo(1)-P(3)
P(3)-Mo(1)-P(1)
48.17(6)
86.08(6)
83.20(6)
P(1)-Mo(1)-P(2)
P(2)-Mo(1)-P(3)
P(3)-Mo(1)-P(1)
49.33(3)
85.33(4)
87.11(4)
P(2)-Mo(1)-Mo(2) 54.83(4)
P(1)-Mo(1)-Mo(2) 51.56(4)
P(2)-Mo(1)-Mo(2) 51.30(3)
P(1)-Mo(1)-Mo(2) 54.50(3)
P(1)-Mo(2)-P(2)
48.70(6)
P(1)-Mo(2)-P(2)
49.33(3)
P(1)-Mo(2)-Mo(1) 53.73(4)
P(2)-P(1)-Mo(2) 68.66(7)
Mo(2)-P(1)-Mo(1) 74.71(5)
P(1)-P(2)-Mo(2) 62.64(6)
P(3)-Mo(1)-Mo(2) 132.40(4) P(3)-Mo(1)-Mo(2) 133.92(3)
P(2)-Mo(2)-Mo(1) 51.44(4) P(2)-Mo(2)-Mo(1) 53.66(3)
P(2)-P(1)-Mo(1) 63.80(6) P(2)-P(1)-Mo(1) 66.97(4)
P(1)-Mo(2)-Mo(1) 51.38(3)
P(2)-P(1)-Mo(2) 62.56(4)
Mo(2)-P(1)-Mo(1) 74.12(3)
P(1)-P(2)-Mo(2) 68.42(4)
Ch a r a cter iza tion of 4 a n d 5. The complexes 4 and
5 have been characterized spectroscopically (see Ex-
perimental Section), and the molecular structures of
5a ,b have, in addition, been determined by single-
crystal X-ray diffraction studies (Figure 1). Table 1 gives
selected bond lengths and angles for complexes 5a ,b.
The P-P bond lengths in the P2 units in 5a (2.077(2)
Å) and 5b (2.085(1) Å) are typical of those in other such
complexes, the bond length in the unsubstituted com-
plex [Cp2(CO)4Mo2(µ-η2-P2)] being 2.079(2) Å7 and that
in the parent complex 1 being 2.085(3) Å. The Mo-Mo
bond lengths of 3.0240(9) and 3.0334(7) Å for 5a ,b,
respectively, are both considerably shorter than that in
the parent complex 2. However, both values fall within
the range of Mo-Mo single-bond lengths reported in
related complexes, which vary from 2.954(1) Å in
[Cp2(CO)2Mo2{µ-η3-CHdCHC(O)Ph}(µ-PPh2)] 8 to 3.349-
(2) Å in 3.3 One long and one short Mo-P bond to each
Mo atom are observed within the Mo2P2 core of both 5a
and 5b. Similarly distinct pairs of Mo-P bond distances
are found in the Mo2P2 core of the unsubstituted
complex [Cp2(CO)4Mo2(µ-η2-P2)], reported by Scherer et
al.7
1
The H NMR spectra of 4a ,b show broad peaks at 9.3
and 8.8 ppm, respectively, which are assigned to the
N-H proton. This is in good agreement with data
recorded by Kramolowsky et al. for the related complex
[(CO)4Mn(PPh2C(S)NHPh)].9
Complexes 5a -c all show rather complicated 1H NMR
spectra, due to the inequivalence of the two protons on
each of the R- and â-carbon atoms of the PPh2CRH2CâH2R
ligand. This is presumably due to the phosphine ligand
being bound to an asymmetric molybdenum center,
causing the protons to become diastereomeric.
Rea ction of 4 a n d 5 w ith CS2. Complexes 4 and 5
both contain acidic protons and were deprotonated with
DBU in order to investigate possible nucleophilic reac-
tion of the resulting anions with CS2. Addition of a slight
excess of DBU (1.15 equiv) to a stirred solution of 4 in
dichloromethane followed by addition of excess CS2
(7) Scherer, O. J .; Sitzman, H.; Wolmerha¨user, G. J . Organomet.
Chem. 1984, 268, C9.
(8) Doel, G. R.; Feasey, N. D.; Knox, S. A. R.; Orpen, A. G.; Webster,
J . J . Chem. Soc., Chem. Commun. 1986, 542.
(9) J ust, B.; Klein, W.; Kepf, J .; Steinhauser, K. G.; Kramolowsky,
R. J . Organomet. Chem. 1982, 229, 49.

A Complex Containing a CSP2S Five-Membered Ring
Organometallics, Vol. 19, No. 6, 2000 987
Sch em e 2
caused an immediate color change from orange to dark
brown. Filtration of the solution through silica yielded
the green-brown complex 3 as the sole product in good
yield (80-90%). In contrast, similar treatment of com-
plexes 5a -c led only to decomposition. A possible
reaction pathway for the formation of 3 from 4a ,b is
shown in Scheme 2. It is suggested that deprotonation
yields the intermediate anion A, which is in equilibrium
with 2 and the free isocyanate; reaction of 2 with CS2
then yields B, the precursor anion of 3. It is presumably
the driving force of the reaction of 2 with CS2 which
pushes the equilibrium between intermediate A and 2
toward 2, thus giving 3 as the sole product (Scheme 2).
The reprotonation of the precursor anion B necessary
for the formation of 3 presumably takes place on the
silica during workup.
proton together with free lone pairs on each sulfur atom
and on one of the phosphorus atoms of the diphosphene
P2 unit. It was therefore of interest to investigate the
susceptibility of 3 toward electrophilic attack.
It seemed possible that deprotonation of the CSP2S
ring at the carbon atom would have a 2-fold effect: it
would increase the nucleophilic character of the lone
pairs on phosphorus and sulfur and would also allow
electrophilic attack at the carbanion. To explore this
possibility, 3 was deprotonated with tBuLi and the
generated anion reacted with methyl iodide. Reaction
of 3 with tBuLi at -78 °C gave an orange solution;
addition of a slight excess of MeI (1.1 equiv) to this
solution and continued stirring at -78 °C for 1 h led to
the formation of [Cp2(CO)3Mo2(µ-η2-P2)(Ph2PC(S)SMe)]
(6) in near-quantitative yield.
Rea ction of [Cp 2(CO)3Mo2(µ-η3-P h 2P C(H)SP 2S)]
(3) w ith Or ga n ic Electr op h iles. The cyclic ligand
µ-η3-PPh2C(H)SP2S possesses several possible sites for
further reaction. In particular, it contains an acidic
The infrared spectrum of 6 shows three absorptions
in the terminal carbonyl region. The pattern of these
absorptions is very similar to those of complexes 4 and
5 and is in marked contrast to that for complex 3. The

988 Organometallics, Vol. 19, No. 6, 2000
Davies et al.
Sch em e 3
31P NMR spectrum of 6 shows a double doublet at δ
100.4 (2J P-P ) 18 Hz; 2J P-P ) 5 Hz), which is assigned
as the phosphine phosphorus atom coupled to the cis
and trans phosphorus atoms of the diphosphene P2 unit.
A doublet of doublets at δ -7.23 (1J P-P ) 484 Hz; 2J P-P
atoms coordinate to a metal carbonyl fragment,10 and
this is proposed to be the first step in the formation of
7 (Scheme 4). Once the iron fragment has coordinated
to the CSP2S ring by a phosphorus lone pair, it is
proposed that further interaction with the sulfur lone
pairs of the CSP2S ring occurs, leading to subsequent
ring cleavage.
To test the first part of the above hypothesis, it was
decided to react 3 with a mononuclear carbonyl complex
having a labile ligand to demonstrate that the initial
step is coordination to a phosphorus, rather than to a
sulfur atom. Reaction of 3 with W(CO)5(THF) did indeed
yield [Cp2(CO)3Mo2(µ-η3-Ph2PC(H)SPP{W(CO)5}S)] (8)
as the only isolable product in good yield (60-70%),
supporting the proposal that the first step in the
formation of 7 involves coordination of iron by phospho-
rus rather than sulfur. The molecular structure of 8 is
shown in Figure 2.
A solution of 3 in dichloromethane was stirred with
DBU and an excess of PhPCl2 at room temperature for
48 h, giving [Cp2(CO)3Mo2(µ-η2-P2)(Ph2P{η3-CS2Mo(O)-
Cp}] (9) as moderately air-stable brown crystals in low
yield (10%). As in the reaction of 3 with Fe2(CO)9, the
Mo2P2 tetrahedrane core has been re-formed, the mo-
lecular structure of 9 being shown in Figure 3. Complex
9 exhibits the added unusual feature of a 16-electron
molybdenum atom coordinated in an allylic fashion by
the dithiolato group. Although there are several ex-
amples of RCS2 acting as a three-electron donor11 to a
) 18 Hz) and a doublet of doublets at δ -17 (1J P-P
)
2
484 Hz, J P-P ) 5 Hz) are assigned to the transoid and
cisoid phosphorus atoms of the P2 unit, respectively.
To investigate whether the ring scission which occurs
during the formation of 6 occurs on deprotonation of 3
t
with BuLi or is promoted by subsequent addition of
MeI, HBF4 was added immediately after the deproto-
nation of 3. This led to re-formation of 3 in near-
quantitative yield, suggesting that it is the addition of
MeI which causes scission.
In situ 31P NMR spectroscopic studies have shown
that the characteristic resonances of the ring-bound
phosphorus atoms are present before reprotonation of
the reaction mixture of 2 + CS2 and are also the sole
t
signals present after the addition of BuLi to complex
3. This leads us to propose that deprotonated 3 can exist
in two resonance forms, either with the negative charge
residing on the ring carbon (C) or on one of the ring
sulfur atoms (D) (Scheme 3). This latter form may be
regarded as a sulfur ylide. Subsequent reaction can then
be rationalized in terms of HSAB theory. Clearly,
resonance form C represents the harder of the two and
would therefore be expected to react with hard electro-
philes such as H+ to yield 3, whereas resonance form D
would react with softer electrophiles such as MeI to
yield 6 (Scheme 3).
Rea ction of 3 w ith Meta l Ca r bon yl Rea gen ts.
Reaction of complex 3 with Fe2(CO)9 at room tempera-
ture for 24 h results in the formation of [Cp2(CO)3Mo2-
(µ-η2-P2)(PPh2C(H)S2Fe2(CO)5] (7) in low yield (15-
20%). The mechanism of formation of 7 has not been
fully elucidated. There is a wealth of documented
reactions in which lone pairs on naked phosphorus
(10) (a) Chatt, J .; Hitchcock, P. B.; Pidcock, A. P.; Warrens, C. P.;
Dixon, K. R. J . Chem. Soc., Dalton Trans. 1984, 2237. (b) Marinetti,
A.; Charnier, C.; Matley, F.; Fischer, J . Organometallics 1985, 4, 2134.
(c) Ceconi, T.; Ghilardi, A.; Midollini, S.; Orlandino, A. Inorg. Chem.
1986, 25, 1766. (d) Scherer, O. J .; Braun, J .; Walther, P.; Wolmer-
ha¨user, G. Chem. Ber. 1992, 125, 2661.
(11) (a) Schenk, W. A.; Rub, D.; Burschka, C. J . Organomet. Chem.
1987, 328, 287. (b) Schenk, W. A.; Rub, D.; Burschka, C. J . Organomet.
Chem. 1987, 328, 305. (c) Ulrich, N.; Herdtweck, E.; Kreissl, F. R. J .
Organomet. Chem. 1990, 397, C9. (d) Tatsumsago, M.; Matsubayashi,
G.; Tanaka, T. J . Chem. Soc., Dalton Trans. 1982, 121.

A Complex Containing a CSP2S Five-Membered Ring
Organometallics, Vol. 19, No. 6, 2000 989
Sch em e 4
dition, complexes 7-9 have been the subject of single-
crystal X-ray diffraction studies; Tables2 and 3 show
selected bond lengths and angles for 7-9.
The Mo-Mo and P-P bond distances of, respectively,
3.079(1) and 2.080(3) Å in complex 7 are both typical of
corresponding bond distances in other complexes con-
taining a Mo2P2 core.3,7,8 However, unlike the other
complexes containing a Mo2P2 unit which have been
previously described, the pattern of two long Mo-P and
two short Mo-P bond lengths is not observed. Rather,
there is one short bond length (Mo(2)-P(2) ) 2.415(2)
Å) and one long bond length (Mo(2)-P(1) ) 2.608(2) Å),
with the bonds to Mo(1) both being intermediate in
length. The Fe-Fe bond length of 2.490(2) Å is typical
of an Fe-Fe single bond, being very similar to the 2.485-
(1) Å observed for this bond in [Fe2(CO)6(µ-SCH2S)].13
The structural features of the Mo2P2 core of 9 are
typical of those of related complexes described previ-
ously, showing a pair of long Mo-P bonds (Mo(2)-P(2)
) 2.547(5) Å, Mo(1)-P(1) ) 2.578(5) Å) and a pair of
short Mo-P bonds (Mo(2)-P(1) ) 2.464(6) Å, Mo(1)-
P(2) ) 2.479(5) Å). The Mo-Mo bond length of 3.045(2)
Å and the P(1)-P(2) bond length of 2.087(7) Å are again
typical of such complexes. The S-C bond lengths of the
thiolato group are equivalent within experimental error
(S(2)-C(26) ) 1.70(2) Å and S(1)-C(26) ) 1.74(2) Å),
while the C(26)-Mo(3) bond distance of 2.20(2) Å is
similar to that reported by Zubieta et al.14 and Dubois
et al.15 for related complexes, thus confirming that the
thiolato group in 9 acts as a η3-allylic donor.
F igu r e 2. Molecular structure of [Cp2(CO)3Mo2(µ-η3-Ph2-
PC(H)SPP{W(CO)5}S)] (8). Hydrogen atoms removed for
clarity. Thermal ellipsoids are shown at the 30% probability
level.
metal, it is rare to find this ligand bonding in an allylic
η3 manner; normally the carbon atom is not involved
in bonding to the metal. The presence of adventitious
oxygen is assumed to lead to the formation of the oxo
group. The allylic CS2 bound molybdenum atom in 9 is
coordinated by several π donor ligands and is formally
in a +5 oxidation state, which helps to explain why it
departs from an 18-electron configuration.
The formation of 9 may be rationalized if it is assumed
that the strongly oxidizing PhPCl2 causes some metal-
metal bond cleavage in 3 to give a mononuclear molyb-
denum complex. This could then react with a further
molecule of 3 to yield 9. This proposal is given credence
by the isolation from the reaction mixture of small
amounts of Cp(CO)3MoCl, which was identified by
comparison of its IR spectrum with literature values.12
Ch a r a cter iza tion of Com p lexes 6-9. Complexes
6-9 have been characterized spectroscopically. In ad-
Coordination of a W(CO)5 unit to one of the diphos-
phene phosphorus atoms of 3 leads to a slight lengthen-
ing of the P-P bond from 2.111(3) Å in 3 to 2.124(3) Å
in 8, although both still fall between the values found
for free diphosphenes16 and for P-P single bonds. The
(13) Shaver, A.; Fitzpatrick, P. J .; Stelious, K.; Butler, I. S. J . Am.
Chem. Soc. 1979, 101, 1313.
(14) Hyde, J .; Venkatsubramaniam, K.; Zubieta, J . Inorg. Chem.
1978, 17, 414.
(15) Coons, D. E.; Laurie, J . C. V.; Haltimeyer, R. C.; Dubois, M. R.
J . Am. Chem. Soc. 1982, 109, 282.
(12) Piper, T. S.; Wilkinson, G. J . Inorg. Nucl. Chem. 1956, 3, 104.
(16) Schmidt, M. W.; Gordon, M. S. Inorg. Chem. 1986, 25, 248.

990 Organometallics, Vol. 19, No. 6, 2000
Davies et al.
F igu r e 3. Molecular structures of (left) [Mo2Cp2(CO)3Fe2(CO)5(µ3-η2-P2)(µ-η-PPh2C(H)S2)] (7) and (right) [Cp2(CO)3Mo2-
(µ-η2-P2)(Ph2P{η3-CS2Mo(O)Cp}] (9). Hydrogen atoms are omitted for clarity. Thermal ellipsoids are shown at the 30%
probability level.
Ta ble 2. Bon d Len gth s (Å) a n d An gles (d eg) for
[Mo2Cp 2(CO)3F e2(CO)5(µ3-η2-P 2)(µ-η-P P h 2C(H)S2)]
(7) a n d
Ta ble 3. Selected Bon d Len gth s (Å), a n d An gles
(d eg) for
[Cp 2(CO)3Mo2(µ-η3-P h 2P C(H)SP P {W(CO)5}S)] (8)
[Cp 2(CO)3Mo2(µ-η2-P 2)(P h 2P {η3-CS2Mo(O)Cp }] (9)
Mo(1)-Mo(2)
Mo(1)-P(2)
Mo(2)-P(1)
Mo(2)-P(2)
Mo(2)-P(3)
W(1)-P(1)
3.389(2)
2.317(3)
2.492(3)
2.443(3)
2.434(3)
2.541(3)
P(1)-P(2)
S(1)-C(9)
S(1)-P(1)
S(2)-C(9)
S(2)-P(2)
2.124(4)
1.82(1)
2.162(4)
1.823(1)
2.127(4)
7
9
Mo(1)-Mo(2)
Mo(1)-P(1)
Mo(1)-P(2)
Mo(1)-P(3)
Mo(2)-P(1)
Mo(2)-P(2)
Fe(1)-P(2)
Fe(1)-S(1)
Fe(1)-S(2)
Fe(1)-Fe(2)
S(1)-C(31)
S(2)-C(31)
P(3)-C(31)
P(1)-P(2)
3.079(1)
2.495(2)
2.475(2)
2.468(2)
2.608(2)
2.415(2)
2.209(2)
2.279(2)
2.275(2)
2.490(2)
1.837(6)
1.837(6)
1.863(7)
2.080(3)
Mo(1)-Mo(2)
Mo(1)-P(1)
Mo(1)-P(2)
Mo(2)-P(1)
Mo(2)-P(2)
Mo(2)-P(3)
Mo(3)-S(1)
Mo(3)-S(2)
Mo(3)-C(26)
Mo(3)-O(4)
P(1)-P(2)
3.045(2)
2.578(5)
2.479(5)
2.464(6)
2.547(5)
2.479(4)
2.353(5)
2.344(5)
2.20(1)
1.67(1)
2.087(7)
1.70(2)
1.74(2)
2.89(2)
P(2)-Mo(1)-Mo(2)
P(2)-Mo(2)-Mo(1)
P(2)-Mo(2)-P(1)
P(2)-P(1)-S(1)
P(2)-P(1)-Mo(2)
P(2)-P(1)-W(1)
P(1)-P(2)-S(2)
P(1)-Mo(2)-Mo(1)
P(1)-P(2)-Mo(1)
46.12(7)
P(1)-P(2)-Mo(2)
65.7(1)
43.13(7)
50.98(9)
98.08(1)
63.31(10)
131.9(1)
105.1(2)
80.82(7)
121.3(1)
S(1)-P(1)-Mo(2) 113.05
S(1)-P(1)-W(1)
S(1)-C(9)-S(2)
107.08
109.9(6)
S(2)-P(2)-Mo(1) 133.6(2)
S(2)-P(2)-Mo(2) 111.3(1)
Mo(2)-P(1)-W(1) 134.0(1)
C(9)-S(2)-P(2)
C(9)-S(1)-P(1)
95.0(4)
96.5(3)
S(1)-C(26)
S(2)-C(26)
P(3)-C(26)
in the 31P NMR spectrum, no 183W coupling could be
resolved.
P(1)-Mo(1)-Mo(2) 54.49(5)
P(1)-Mo(2)-Mo(1) 51.24(5)
P(1)-Mo(1)-Mo(2) 51.2(1)
P(1)-Mo(2)-Mo(1) 54.6(1)
P(1)-P(2)-Mo(1)
P(1)-P(2)-Mo(2)
P(1)-P(2)-Fe(1)
P(2)-Mo(1)-P(1)
P(2)-Fe(1)-S(2)
P(2)-Fe(1)-S(1)
P(2)-Fe(1)-Fe(2)
S(1)-Fe(1)-Fe(2)
S(1)-Fe(2)-Fe(1)
S(1)-C(31)-S(2)
S(1)-C(31)-P(3)
S(2)-Fe(1)-Fe(2)
S(2)-Fe(2)-Fe(1)
S(2)-Fe(1)-S(1)
S(2)-Fe(2)-S(1)
Fe(1)-P(2)-Mo(1)
65.77(8)
70.49(9)
129.7(1)
49.48(7)
99.59(8)
95.17(9)
P(1)-P(2)-Mo(1)
P(1)-P(2)-Mo(2)
P(1)-Mo(2)-P(2)
P(1)-Mo(2)-P(3)
68.1(2)
63.3(2)
49.2(2)
87.8(2)
Exp er im en ta l Section
Gen er a l P r oced u r e. Unless otherwise stated, all experi-
ments were carried out under an atmosphere of dry, oxygen-
free nitrogen, using conventional Schlenk line techniques, and
solvents were freshly distilled from the appropriate drying
agent. NMR spectra were recorded in CDCl3 using a Bruker
DRX 250 spectrometer, with TMS as an external standard for
1H and 13C spectra and 85% aqueous H3PO4 for 31P spectra.
Infrared spectra were, unless otherwise stated, recorded in
dichloromethane solution in 0.5 mm NaCl solution cells, using
a Perkin-Elmer 1710 Fourier transform spectrometer. FAB
mass spectra were obtained with a Kratos MS 890 instrument,
using 3-nitrobenzyl alcohol as a matrix.
P(2)-Mo(1)-Mo(2) 53.8(1)
P(2)-Mo(2)-Mo(1) 51.7(1)
146.68(7) P(2)-P(1)-Mo(1)
63.2(2)
67.5(2)
119.7(1)
57.08(7)
56.81(6)
94.1(3)
118.1(3)
57.11(6)
56.71(6)
72.37(3)
72.05(8)
P(2)-P(1)-Mo(2)
S(1)-C(26)-S(2)
S(1)-C(26)-Mo(3) 73.0(6)
S(1)-C26)-P(3)
S(2)-C(26)-Mo(3) 72.0(6)
118.0(1)
121.8(1)
S(2)-C(26)-P(3)
C(26)-Mo(3)-S(1) 43.8(5)
C(26)-Mo(3)-S(2) 45.0(5)
132.94(9) C(26)-S(2)-Mo(3) 63.1(6)
Preparative TLC was carried out on 1 mm silica plates
prepared at the University of Cambridge. Column chromatog-
raphy was performed on Kieselgel 60 (70-230 mesh ASTM).
Unless otherwise stated, all reagents were obtained from
commercial suppliers and used without further purification.
[Cp2(CO)4Mo2(µ-η2-P2)]7 was prepared by the literature method.
Cr ysta l Str u ctu r e Deter m in a tion s: Data were collected
by the ω/2θ scan method on a Rigaku AFC7R four-circle
diffractometer for the complexes 5a ,b and on a Rigaku AFC5R
four-circle diffractometer for complex 7. In each case, cell
parameters were obtained by least-squares refinement on
diffractometer angles from 25 centered reflections (15 < θ <
31P NMR spectrum of 8 shows that the diphosphene
phosphorus atoms are coupled. A J P-P coupling con-
1
stant of 394 Hz in 8, as compared to 446 Hz for the
corresponding coupling in 3, probably reflects a slight
decrease in the P-P bond order in 8. It is still, however,
indicative of a large degree of multiple bonding, as
suggested also by the X-ray analysis. The P-W bond
length of 2.541(3) Å is typical for such a bond.10 The
Mo-Mo separation in 8 remains the same as in 3 within
experimental error. Because of the breadth of the peaks

A Complex Containing a CSP2S Five-Membered Ring
Organometallics, Vol. 19, No. 6, 2000 991
Ta ble 4. Cr ysta llogr a p h ic Da ta for Com p lexes 5a ,b a n d 7-9a
5a
5b
7
8
9
formula
C
29H27Mo2O5P3
C28H24Mo2NO3P3
C31H21Fe2Mo2O8
P3S2‚CH2Cl2
1067.01
C31H21Mo2O8P3S2W
C30H25Mo3O4P3S2‚
3/2CH2Cl2
1030.24
Mr
740.3
707.27
1054.24
temp/K
180(2)
180(2)
293(2)
180(2)
180(2)
instrument used
cryst size (mm)
cryst syst
space group
a/Å, R/deg
b/Å, â/deg
c/Å, γ/deg
V/Å3
AFC7R
AFC7R
AFC5R
RAXIS
RAXIS
0.30 × 0.20 × 0.18
monoclinic
P21/c
11.713(3), 90
13.983(3), 100.27(2)
17.662(4), 90
2846.4(11)
4
0.30 × 0.25 × 0.30
monoclinic
P21/n
11.804(3), 90
13.162(3), 93.08(2)
17.795(4), 90
2760.7(11)
4
0.30 × 0.20 × 0.20
0.18 × 0.15 × 0.02
monoclinic
P21/n
10.393(5), 90
30.476(4), 102.13(4)
10.931(5), 90
3385(2)
0.2 × 0.06 × 0.05
monoclinic
C2
22.306(6), 90
9.444(5), 116.51(4)
19.455(5), 90
3667(2)
triclinic
P1h
13.068(4), 107.07(2)
14.483(3), 94.93(3)
10.847(4), 84.09(2)
1948.7(10)
2
Z
4
4
Dc/Mg m-3
abs coeff/mm-1
F(000)
1.728
1.088
1480
1.702
1.113
1408
1.818
1.773
1052
2.069
4.434
2024
1.866
1.510
2028
θ range/deg
2.67-27.5
0 e h e 15,
0 e k e 18,
-22 e l e 20
6808
3.55-27.51
0 e h e 15,
0 e k e 17,
-23 e l e 23
6618
1.57-22.5
0 e h e 14,
-15 e k e 15,
-11 e l e 11
5354
3.63-25.22
0 e h e 12,
0 e k e 36,
-13 e l e 12
10 325
1.84-25.17
0 e h e 26,
0 e k e 11,
-23 e l e 20
6400
index ranges
no. of rflns measd
no. of indep rflns
Rint
6507
0.0526
6318
0.0484
5084
0.0400
5786
0.0583
3443
0.0548
max, min transmissn
goodness of fit on F2
final R indices
(I > 2σ(I))
0.994, 0.924
1.018
1.000, 0.950
1.017
0.999, 0.909
1.027
0.9166, 0.5024
0.902
0.9283, 0.7251
0.991
R1
0.0542
0.1078
0.037
0.0825
0.0407
0.0779
0.05
0.0819
0.0619
0.1532
wR2
R indices (all data)
R1
0.1009
0.0449
0.1007
0.0933
0.0869
wR2
0.1281
0.0908
0.2905
0.0934
0.1660
largest peak,
0.855, -0.675
0.496, -0.872
0.744, -0.757
1.001, -1.386
2.008, -1.053
hole/e Å-3
a
For all complexes, graphite-monochromated Mo KR radiation, λ ) 0.710 73 Å, was used.
20°). Semiempirical absorption corrections based on ψ-scan
data were applied.17,18
Data for the complexes 8 and 9 were collected on a Rigaku
RAXIS IIc image plate. Data processing and reduction, includ-
ing refinement of the cell dimensions, was performed using
the “Process” software written by Higashi.19
For the determination of complexes 5a ,b, 8, and 9 the
crystal was cooled to 180(2) K using an Oxford Cryostream
cooling apparatus.
The structures were solved by direct methods (SIR 92)20 and
subsequent Fourier difference syntheses. For 5a ,b, 7, and 8
structures were refined anisotropically on all non-hydrogen
atoms by full-matrix least squares on F2 (SHELXL 93).21
Hydrogen atoms were placed in idealized positions and refined
using a riding model. In the final cycles of refinement a
weighting scheme was introduced which produced a flat
analysis of variance.
For 9, the crystal quality and parameter/data ratio were
poor: heavy atoms only were refined anisotropically. Common
isotropic temperature factors were used for the Cp rings. The
unit cell contains two CH2Cl2 molecules, one of which is
disordered around a diad axis.
Atomic coordinates, bond lengths and angles, and thermal
parameters have been deposited at the Cambridge Crystal-
lographic Data Centre (CCDC). Any request to the CCDC for
this material should quote the full literature citation. Table 4
gives crystallographic data for complexes 5a ,b and 7-9.
Rea ction of [Cp 2(CO)4Mo2(µ-η2-P 2)] w ith P P h 2H. To a
solution of [Cp2(CO)4Mo2(µ-η2-P2)] (400 mg, 0.806 mmol) in
toluene (80 mL) was added diphenylphosphine (160 mg, 0.85
mmol), and the resulting mixture was heated to reflux for 7
days, after which time spot TLC analysis did not reveal the
presence of any starting material. The solvent was removed
under reduced pressure; the residue was redissolved in the
minimum amount of CH2Cl2, absorbed onto silica, pumped dry,
and applied to the top of a chromatography column. Elution
with 2:1 CH2Cl2-hexane gave orange crystalline [Cp2(CO)3-
Mo2(µ-η2-P2)(PPh2H)] (1) in 94% yield. IR: ν(CO) 1957 cm-1
1
(s), 1894 cm-1 (vs). H NMR: δ 7.2-7.6 (m, 10H, Ph), 6.59 (d,
1J P-H ) 368 Hz, 1H, PPh2H), 5.07 (s, 5H, Cp), 4.77 (d, 3J P-H
)
2
2.4 Hz, 5H, Cp). 31P{1H} NMR: δ 40.05 (d, J P-P ) 45 Hz,
1
2
PPh2H), -31.05 (dd, J P-P ) 472 Hz, J P-P ) 45 Hz, µ-η2-P2),
-77.25 (d, 472 Hz, µ-η2-P2). Anal. Calcd for C25H21Mo2O3P3:
C, 45.87; H, 3.21; P, 14.22. Found: C, 45.53; H, 3.08; P, 14.10.
FAB-MS: m/z 654 (M+), 600 (M+ - 2CO).
Rea ction of [Cp 2(CO)3Mo2(µ-η2-P 2)(P P h 2H)] (1) w ith
DBU. To a solution of 1 (400 mg, 0.6 mmol) in CH2Cl2 (50
mL) was added DBU (0.1 g, 1.1 equiv), and the mixture was
stirred for 1 h, during which time the solution turned dark
orange due to the formation of [Cp2(CO)3Mo2(µ-η2-P2)(PPh2)]-
(2). The solution was used for further reactions without the
isolation of 2.
Rea ction of [Cp 2(CO)3Mo2(µ-η2-P 2)(P P h 2)]- (2) w ith
CS2. To a solution of 2 (250 mg, 0.38 mmol) in CH2Cl2 was
added CS2 (0.5 mL, large excess), and the solution was stirred
for 2 h, during which time the solution turned a deeper brown.
A slight deficiency of 85% HBF4‚OEt2 (62 mg, 0.85 equiv) was
added, the solution filtered through a silica pad, and the
solvent removed under reduced pressure to yield green-brown
[Cp2(CO)3Mo2(µ-η3-Ph2PC(H)SP2S)] (3) as the sole product (220
(17) TeXsan, version 1.7-1; Molecular Structure Corp., The Wood-
lands, TX, 1985, 1992, 1995.
(18) North, A. C. T.; Philips, D. C.; Matthews, F. S. Acta Crystallogr.
1968, A24, 351.
(19) Higashi, T. PROCESS: A Program for Indexing and Processing
R-Axis II Imaging Plate Data; Rigaku Corp., Tokyo, 1990.
(20) Altomare, A.; Cascarano, G.; Giacavazzo, C.; Guagliardi, A.;
Byrla, M. C.; Polidori, G.; Camalli, M. J . Appl. Crystallogr. 1994, 27,
435.
(21) Sheldrick, G. M. SHELXL 93; University of Go¨ttingen, Go¨ttin-
gen, Germany, 1993.

992 Organometallics, Vol. 19, No. 6, 2000
Davies et al.
mg, 80% yield). For smaller scale reactions it was not necessary
to add a proton source to the reaction mixture in order to
isolate the neutral product. Instead the mixture was filtered
through silica and repeatedly washed with CH2Cl2 to yield 3.
Slow diffusion of hexane into a CH2Cl2 solution of 3 yielded
green-brown crystals suitable for X-ray diffraction. IR: ν(CO)
1958 (vs), 1910 (m), 1851 cm-1 (m). 1H NMR: δ 7.6-7.0 (m,
Hz, Ph2PCH2CH2COOMe). Anal. Calcd for C29H27Mo2O5P3: C,
47.05; H, 3.68; P, 12.55. Found: C, 47.59; H, 3.73; P, 11.95.
FAB-MS: m/z M+ 739.
(b) Acr ylon itr ile. The same procedure was followed for the
reaction of 2 with acrylonitrile; a 10% excess of acrylonitrile
was added to a solution of 2, to yield after 3:2 CH2Cl2-hexane
elution on TLC plates 1 (12 mg, 8%) and orange crystalline
[Cp2(CO)3Mo2(µ-η2-P2)(PPh2C2H4CN)] (5b; 146 mg, 85%). Slow
evaporation of a hexane/CH2Cl2 solution yielded orange crys-
tals suitable for X-ray diffraction. IR: ν(CO) 1957 (s), 1902
(vs), 1868 (s, sh). 1H NMR: δ 7.75-7.21 (m, 10H, Ph), 5.12 (s,
2
10H, Ph), 5.52 (ddd, 1H, J P-H ) 24, 4, 4 Hz, S2CH), 5.24 (s,
1
5H, Cp), 5.16 (s, 5H, Cp). 31P{1H} NMR: δ 205.45 (d, J P-P
)
446 Hz, Mo-PdPS2CH), 145.65 (s, PPh2), -0.25(d, 1J P-P ) 446
Hz, Mo-PdPS2C). 13C NMR: δ 242.3 (s, CO), 134-127 (m,
Ph), 89.8 (s, Cp), 84.2 (s, Cp), 63.9 (d, 1J P-C ) 41 Hz, Ph2PC(H)-
S2). Anal. Calcd for C26H21Mo2O3P3S2‚1/2CH2Cl2: C, 41.18; H,
2.87; P, 12.02. Found: C, 40.43; H, 2.82; P, 11.37. FAB-MS:
m/z 730 (M+).
3
5H, Cp), 4.63 (d, J P-H ) 1.9 Hz, 5H, Cp), 2.93-2.64 (m, 2H,
PCH2), 2.38-2.03 (m, 2H, PCH2CH2). 31P{1H} NMR: δ 50.88
1
(s (b), Ph2PC2H4CN), -36,60 (d, J P-P ) 476.5 Hz, cis-µ-η2-
1
P2), -42.62 (d, J P-P ) 476.5 Hz, trans-µ-η2-P2). 13C NMR: δ
Rea ction of [Cp 2(CO)3Mo2(µ-η2-P 2)(P P h 2)]- (2) w ith
3-ClC6H4NCO. To a solution of 2 (250 mg, 38 mmol) was
added 3-ClC6H4NCO (11.67 mg, 2 equiv), and the solution was
stirred overnight. The solution was then filtered through a
silica pad and the solvent removed under reduced pressure,
after which the residue was redissolved in the minimum
amount of CH2Cl2 and applied to the base of TLC plates.
Elution with a 3:2 CH2Cl2-hexane mixture yielded the starting
material 1 (22 mg, 9%) and orange crystalline [Cp2(CO)3Mo2-
(µ-η2-P2)(P(Ph)2C(O)NH3-ClC6H4)] (4a ; 240 mg, 80%). IR: ν-
(CO) 1961 (vs), 1897 cm-1 (s). 1H NMR: δ 9.3 (s, 1H, NH),
243.84 (s, CO), 231.75 (s, CO), 223.24 (s, CO), 138.924-125.737
1
(m, Ph), 86.485 (s, Cp), 85.39 (s, Cp) 32.38 (d, J P-C ) 45.5,
2
Ph2PCH2R), 14.44 (d, J P-C ) 16 Hz, Ph2PCH2CH2CN). Anal.
Calcd for C28H24Mo2NO3P3: C, 47.55; H, 3.42; N, 1.98; P, 13.14.
Found: C, 47.44; H, 3.34; N, 1.94; P, 13.27. FAB-MS: m/z
709.7 (M+), 656.5 (M+ - 2CO).
(c) MVK. The same reaction was repeated using a 10%
excess of MVK as the Michael acceptor, to yield, after elution
with 3:2 CH2Cl2-hexane on TLC plates, trace 1 and orange
crystalline [Cp2(CO)3Mo2(µ-η2-P2)(PPh2C2H4C(dO)Me)] (5c;
116 mg, 68%). IR: ν(CO) 1958 (s), 1891 (vs), 1864 cm-1 (s, sh).
1H NMR: δ 7.82-7.18 (m, 10H, Ph), 5.08 (s, 5H, Cp), 4.57 (d,
3J P-H ) 1.7 Hz, 5H, Cp), 3.65-3.40 (m, 2H, PCH2), 2.92-2.48
(m, 2H, PCH2CH2), 2.0 (s, 3H, COCH3). 31P{1H} NMR: δ 50.12
3
7.88-7.09 (m, 14H, Ph), 5.11 (s, 5H, Cp), 4.69 (d, J P-H ) 1.9
Hz, 5H, Cp). 31P{1H} NMR: δ 66.98 (dd, 2J P-P ) 30.8 Hz, 2J P-P
) 7.6 Hz, PPh2C(O)NH3-ClPh), -30.27 (dd, 1J P-P ) 473.4 Hz,
1
2J P-P ) 30.8 Hz, trans-µ-η2-P2), -46.40 (dd, J P-P ) 473.4 Hz,
1
(s, Ph2PC2H4COMe), -34.39 (d, J P-P ) 479 Hz, trans-µ-η2-
2J P-P ) 7.6 Hz, cis-µ-η2-P2). 13C NMR: δ 229 (CO), 205 (CO),
189 (Ph2PC(O)NH), 136-122 (m, Ph), 88.3 (s, 5H, Cp), 87.1
(s, 5H, Cp). Anal. Calcd for C32ClH25Mo2NO4P3: C, 47.58; H,
3.12; P, 11.5; N, 1.73. Found: C, 46.8; H, 3.19; P, 11.57; N,
1.59. FAB-MS: m/z 807 (M+).
P2), -41.81 (d, 1J P-P ) 479 Hz, cis-µ-η2-P2). 13C NMR: δ 243.1
(s, CO), 223.14 (s, CO), 223.841 (s, CO), 206.56 (d, 3J P-C ) 10.7
Hz, Ph2C2H4C(O)Me), 140.3-128.15 (m, Ph), 86.53 (s, Cp),
1
85.27 (s, Cp), 30.03 (s, COCH3), 29.45 (d, J P-C ) 28 Hz,
2
Ph2PCH2), 29.08 (d, J P-C ) 18.5 Hz). Anal. Calcd for C29H27
-
Rea ction of [Cp 2(CO)3Mo2(µ-η2-P 2)(P P h 2)]- (2) w ith
P h NCS. The same procedure as in the previous paragraph
was applied using a 2-fold excess of PhNCS to yield, after
elution with 3:2 hexane-CH2Cl2, orange crystalline [Cp2(CO)3-
Mo2(µ-η2-P2)(PPh2C(S)NHPh)] (4b; 256 mg, 85% yield) as the
sole product. IR: ν(CO) 1961 (vs), 1897 (s), 1874.5 cm-1 (s, sh).
1H NMR: δ 8.80 (s, 1H, NH), 7.92-7.2 (m, 15H, Ph), 5.12 (s,
Mo2O4P3: C, 48.09; H, 3.76; P, 12.83. Found: C, 47.71; H, 3.63;
P, 12.53. FAB-MS: m/z 726.8 (M+).
Reaction of [Cp2(CO)3Mo2(µ-η3-P h 2P C(H)SP 2S)] (3) with
tBu Li a n d MeI. A solution of 3 (250 mg, 0.34 mmol) in THF
t
(50 mL) was cooled to -78 °C, and a 1.7 M solution of BuLi
(0.2 mL, 1.1 equiv) was added over 10 min, during which time
the color changed to deep orange. To the resulting mixture
MeI was added (53 mg, 1.1 equiv), and the solution was stirred
for 1/2 h at -78 °C, during which time the color changed from
orange to purple. The resulting solution was filtered through
a pad of silica and solvent removed in vacuo to yield purplee-
brown [Cp2(CO)3Mo2(µ-η2-P2)(Ph2PC(S)SMe)] (6) as the sole
product (182 mg, 72%). IR: ν(CO) 1957 (s), 1892 (vs), 1863
(m, sh) cm-1. 1H NMR: δ 7.85-7.38 (m, 10H, Ph), 5.07 (s, 5H,
3
5H, Cp), 4.68 (d, J P-H ) 1.7 Hz, 5H, Cp). 31P{1H} NMR: δ
2
88.94 (dd, J P-P ) 23.6, 7.4 Hz, PPh2PhC(S)NH), -19.69 (dd,
2
1J P-P ) 476 Hz, J P-P ) 23.6 Hz, trans-µ-η2-P2), -40.63 (dd,
2
1J P-P ) 467 Hz, J P-P ) 7.4 Hz, cis-µ-η2-P2). Anal. Calcd for
C
32H26Mo2NO3P3S: C, 48.69; H, 3.32; P, 11.77; N, 1.85.
Found: C, 47.96; H, 3.13; P, 11.12; N, 1.85. FAB-MS: m/z
792.9 (M+).
3
Cp), 4.6 (d, J P-H ) 1.8 Hz, 5H, Cp), 2.30 (s, 3H, SCH3). 31P-
Rea ction of [Cp 2(CO)3Mo2(µ-η2-P 2)(P P h 2)]- (2) w ith
Mich a el Accep tor s. Meth yl Acr yla te. To a solution of 2 (150
mg, 0.22 mmol) was added methyl acrylate (0.25 mL, 0.27
mmol), and the mixture was stirred for 2 h, during which time
the solution color changed from orange-brown to deep orange,
after which a slight deficiency of 85% HBF4‚OEt2 (37 mg, 0.85
equiv) was added. The solvent was removed in vacuo, redis-
solved in the minimum amount of CH2Cl2, and applied to the
base of TLC plates. Elution with 3:2 hexane-CH2Cl2 yielded,
in addition to a trace of starting material 1, orange crystalline
[Cp2(CO)3Mo2(µ-η2-P2)(PPh2C2H4COOMe)] (5a ), in 70% yield.
Slow evaporation of a CH2Cl2-hexane solution yielded orange
crystals of suitable quality for X-ray diffraction analysis. IR:
2
2
{1H} NMR: δ 100.43 (dd, J P-P ) 18.2 Hz, J P-P ) 5.2 Hz,
Ph2PCS2Me), -7.32 (dd, 1J P-P ) 484.6 Hz, 2J P-P ) 18.2, trans-
µ-η2-P2), -20.32 (dd, J P-P ) 484.6 Hz, J P-P ) 5.2, cis-µ-η2-
P2). Anal. Calcd for C27H23Mo2O3P3S2: C, 43.57, H, 3.11, P,
12.48. Found: C, 43.04, H, 3.46, P, 11.99. FAB-MS: m/z 743
(M+).
1
2
Reaction of [Cp2(CO)3Mo2(µ-η3-P h 2P C(H)SP 2S)] (3) with
tBu Li a n d HBF 4. A solution of 3 (250 mg, 0.34 mmol) in THF
t
(50 mL) was cooled to -78 °C, and a 1.7 M solution of BuLi
(0.2 mL, 1.1 equiv) was added over 10 min, during which time
the color changed to deep orange. To the resulting mixture
was added a slight deficiency of 85% HBF4‚OEt2 (55 mg, 0.85
1
1
ν(CÃ) 1956.8 (vs), 1891.6 (s), 1862.3 cm-1 (s, sh). H NMR: δ
equiv), and the solution was stirred for /2 h at -78 °C, during
3
which time the color changed from orange to green. The
resulting solution was filtered through a pad of silica and
solvent removed in vacuo to yield green-brown [Cp2(CO)3Mo2(µ-
η3-Ph2PC(H)SP2S)] (3) as the sole product (208 mg, 83%).
Reaction of [Cp2(CO)3Mo2(µ-η3-P h 2P C(H)SP 2S)] (3) with
F e2(CO)9. To a solution of 3 (208 mg, 0.285 mmol) in THF (50
mL) was added Fe2(CO)9 (excess), and the mixture was stirred
at room temperature for 16 h. The solvent was removed under
7.64-7.37 (m, 10H, Ph), 5.09 (s, 5H, Cp), 4.65 (d, J P-H ) 2
Hz, 5H, Cp), 3.59 (s, 3H, OCH3), 2.86-2.44 (m, 2H, Ph2CH2),
2.17-2.06 (m, 2H, PCH2CH2). 31P{1H} NMR: δ 49.87 (s, P,
MoPPh2), -32.05 (d, 1J P-P ) 477 Hz, µ-η2-P2), -40.72 (d, 1J P-P
) 477 Hz, µ-η2-P2), 13C NMR: δ 232.29 (CO), 223.81 (CO),
3
216.54 (CO), 172.74 (d, J P-C ) 1.3 Hz, C(dO)OMe), 135-
127.80 (m, Ph), 87.93 (s, Cp), 83.98 (s, Cp), 60.42 (s, OCH3),
1
2
31.02 (d, J P-C ) 30 Hz, Ph2PCH2CH2), 15.05 (d, J P-C ) 9

A Complex Containing a CSP2S Five-Membered Ring
Organometallics, Vol. 19, No. 6, 2000 993
reduced pressure and the residue redissolved in the minimum
quantity of CH2Cl2 and applied to the base of TLC plates.
Elution with 1:1 CH2Cl2-hexane gave brown crystalline [Mo2-
Cp2(CO)3Fe2(CO)5(µ3-η2-P2)(µ-η-PPh2C(H)S2)] (7; 41 mg, 15%).
IR: ν(CO) 2045 (vs), 1991 (vs), 1978 (s), 1962 (sh), 1937 (w),
THF (50 mL), cooled to -78 °C, was added a 1.7 M solution of
tBuLi (0.18 mL, 1.1 equiv) over 10 min, during which time the
color changed to deep orange. To the resulting mixture was
added PhPCl2 (100 mg, 2 equiv), and the resulting solution
was warmed to room temperature and stirred for 48 h. The
solvent was removed under reduced pressure and the residue
redissolved in the minimum quantity of CH2Cl2 and applied
to the base of TLC plates. Elution with 2:1 CH2Cl2-hexane
yielded, in addition to a trace of starting material and
decomposition products, [Cp2(CO)3Mo2(µ-η2-P2)(Ph2P{η3-CS2-
Mo(O)Cp}] (9) as moderately air-stable brown crystals in low
yield (22 mg, 10%). IR: ν(CO) 1959 (s), 1896 (vs), 1860 (s, sh)
1
1912 (m), 1894 (sh) cm-1. H NMR: δ 7.7-7.0 (m, 10H, Ph),
5.48 (s, 5H, Cp), ∼5.46 (obscured, S2CH), 4.61 (s, 5H, Cp). 31P-
{1H} NMR: 74.25 (s, Ph2P), 21.05 (br d, 1J P-P ) 480 Hz, trans-
1
µ-η2-P2), -107.15 (v br, d, J P-P ) 480 Hz). Anal. Calcd for
C
31Fe2H21Mo2O8P3S2‚CH2Cl2: C, 35.99; H, 2.16; P, 8.72.
Found: C, 34.99; H, 2.11; P, 8.35. FAB-MS: m/z 983 (M+), M+
- nCO (n ) 3-8).
Reaction of [Cp2(CO)3Mo2(µ-η3-P h 2P C(H)SP 2S)] (3) with
W(CO)5(THF ). To a freshly prepared solution of W(CO)5(THF)
(200 mg, 2 equiv) in THF (80 mL) was added 3 (200 mg, 0.27
mmol), and the resulting solution was stirred for 16 h. Solvent
was removed under reduced pressure and the residue redis-
solved in the minimum quantity of CH2Cl2, applied to the base
of TLC plates, and eluted with 3:2 CH2Cl2-hexane to yield
[Cp2(CO)3Mo2(µ-η3-Ph2PC(H)SPP{W(CO)5}S)] (8; 173 mg, 60%)
and unreacted starting material 3 (20 mg, 10%). Brown
crystals of 8 suitable for X-ray diffraction were grown from
slow evaporation of a CH2Cl2-hexane solution. IR: ν(CO) 2070
(m), 1973.2 (w, sh), 1955.1 (m), 1936.6 (vs), 1866 (m) cm-1. 1H
NMR: δ 7.46-7.1 (m, 10H, Ph), 5.44 (s, 5H, Cp), 5.33 (s, 5H,
Cp), 5.25 (t, 2J P-H ) 25.2 Hz, 2J P-H ) 25.2 Hz, 1H, S2CH). 31P-
cm-1. H NMR: δ 7.5-7.14 (m, 10H, Ph), 5.91 (s, 5H, Mo(O)-
1
Cp), 5.11 (s, 5H, Cp), 4.81 (d, 3J P-P ) 1.8 Hz, 5H, Cp). 31P{1H}
NMR: δ 95.69 (dd, 2J P-P ) 20.2 Hz, 2J P-P ) 6.7 Hz, Ph2PCS2),
1
2
-12.34 (dd, J P-P ) 483.9 Hz, J P-P ) 20.2 Hz, trans-µ-η2-P2),
-34.9 (dd, J P-P ) 483.9 Hz, J P-P ) 6.7, cis-µ-η2-P2). Anal.
Calcd for C31H20Mo3O4P2S2‚3/2CH2Cl2: C, 37.6; H, 2.69; P, 9.02.
Found: C, 38.01; H, 2.93; P, 9.01. FAB-MS: m/z 912.8 (M+).
1
2
Ackn owledgm en t. We thank the EPSRC for awards
to A.D.W. and P.K.T. and ICI for a CASE award to
A.D.W. We gratefully acknowledge Dr. S. Nicholson and
Dr. K. Smith of Albright and Wilson Ltd for the
generous donation of white phosphorus.
1
{1H} NMR: δ 156.32 (br d, J P-P ) 394 Hz, (CO)5W-PdP),
Su p p or tin g In for m a tion Ava ila ble: Tables of crystal-
lographic data and data collection details, atomic coordinates,
bond distances and angles, anisotropic thermal parameters,
and hydrogen atom coordinates. This material is available free
of charge via the Internet at http://pubs.acs.org.
1
146.28 (s, Ph2PC), -10.465 (br d, J P-P ) 394 Hz, (CO)5W-
PdP). Anal. Calcd for C31H21Mo2O8P3S2W: C, 35.32; H, 2.01;
P, 8.81. Found: C, 36.03; H, 2.39; P, 8.52. FAB-MS: m/z 1054.4
(M+), M+ - nCO (n ) 3-5).
Reaction of [Cp2(CO)3Mo2(µ-η3-P h 2P C(H)SP 2S)] (3) with
tBu Li a n d P h P Cl2. To a solution of 3 (200 mg, 0.27 mmol) in
OM990729K