Reactions of heterodinuclear Fe-Pt and Fe-Pd complexes with cyclic bis(amino)germylenes and -stannylenes: A bridging metal(II) amide unit between two different transition metal centers and donor stabilization of terminal germylene and stannylene ligands by Si(OMe)3

Article abstract of DOI:10.1021/om960167u

Reaction of the cyclic amides EN^tBuSiMe₂N^tBu (E = Ge, Sn) with the heterobimetallic complexes [(OC)₃Fe(μ-CO)(μ-Ph₂PXPPh₂)Pt(PR ₃)](Fe-Pt) (X = CH₂, NH; R = phenyl, p-tolyl) occurs by selective substitution of the bridging carbonyl ligand and yields the stannylene-and germylene-bridged complexes [(OC)₃Fe{μ-EN^tBuSiMe₂N ^tBu}(μ-Ph₂PXPPh₂)Pt(PR₃)](Fe-Pt) (2a, X = CH₂, E = Sn, R = Ph; 2b, X = NH, E = Sn, R = Ph; 2c, X = CH₂, E = Sn R = p-tol; 3a, X = CH₂, E = Ge, R = Ph; 3b, X = NH, E = Ge, R = Ph). When GeN^tBuSiMe₂N-^tBu was added in excess to the germylene complex 3a, the tetranuclear complex [(OC)₃Fe-{μ-GeN^tBuSiMe₂N^tBu }(μ-dppm)Pt {GeN^tBuSiMe₂N^tBu}](Fe-Pt) (4) was formed, which is in equilibrium with 3a. The heterobimetallic Si(OMe)₃-substituted complexes mer-[(OC)₃Fe-{μ-Si(OMe)₂(OMe)}(μ-dppm)M(Me)](Fe-M) (M = Pd, Pt) react with EN^tBuSiMe₂N^tBu (E = Ge, Sn) by opening of the four-membered Fe-Si-O-M ring to give the complexes mer-[(OC)₃Fe{μ-Si(OMe)₂(OMe)}{EN^tBuSiMe ₂N^tBu}{μ-dppm)M}(Me)](Fe-M) (5, M = Pt, E = Sn; 6, M = Pd, E = Sn; 7, M = Pd, E = Ge) which contain a five-membered Fe-Si-O-E-M ring. The expected insertion of the amides EN^tBuSiMe₂N^tBu into the M-Me bond was not observed. The dynamic behavior of these intramolecularly base-stabilized trimetallic germylene and stannylene complexes, which is due to a rapid exchange of the methoxy groups coordinated on E, was investigated by variable-temperature ¹H-NMR spectroscopy. All complexes were characterized by multinuclear NMR spectroscopy, and the solid-state structure of 7 was determined by X-ray diffraction.

Full text of DOI:10.1021/om960167u

3868
Organometallics 1996, 15, 3868-3875
Rea ction s of Heter od in u clea r F e-P t a n d F e-P d
Com p lexes w ith Cyclic Bis(a m in o)ger m ylen es a n d
-sta n n ylen es: A Br id gin g Meta l(II) Am id e Un it betw een
Tw o Differ en t Tr a n sition Meta l Cen ter s a n d Don or
Sta biliza tion of Ter m in a l Ger m ylen e a n d Sta n n ylen e
†
Liga n d s by Si(OMe)3
Michael Knorr,*,‡ Eva Hallauer,‡ Volker Huch,‡ Michael Veith,*,‡ and
Pierre Braunstein*,§
Institut fu¨r Anorganische Chemie, Universita¨t des Saarlandes, Postfach 151150,
D-66041 Saarbru¨cken, Germany, and Laboratoire de Chimie de Coordination, URA 0416
CNRS, Universite´ Louis Pasteur, 4 rue Blaise Pascal, F-67070 Strasbourg Cedex, France
Received March 5, 1996X
Reaction of the cyclic amides ENtBuSiMe2NtBu (E ) Ge, Sn) with the heterobimetallic
complexes [(OC)3Fe(µ-CO)(µ-Ph2PXPPh2)Pt(PR3)](Fe-Pt) (X ) CH2, NH; R ) phenyl, p-tolyl)
occurs by selective substitution of the bridging carbonyl ligand and yields the stannylene-
and germylene-bridged complexes [(OC)3Fe{µ-ENtBuSiMe2NtBu}(µ-Ph2PXPPh2)Pt(PR3)](Fe-
Pt) (2a , X ) CH2, E ) Sn, R ) Ph; 2b, X ) NH, E ) Sn, R ) Ph; 2c, X ) CH2, E ) Sn, R
) p-tol; 3a , X ) CH2, E ) Ge, R ) Ph; 3b, X ) NH, E ) Ge, R ) Ph). When GeNtBuSiMe2N-
tBu was added in excess to the germylene complex 3a , the tetranuclear complex [(OC)3Fe-
{µ-GeNtBuSiMe2NtBu}(µ-dppm)Pt {GeNtBuSiMe2NtBu}](Fe-Pt) (4) was formed, which is
in equilibrium with 3a . The heterobimetallic Si(OMe)3-substituted complexes mer-[(OC)3Fe-
{µ-Si(OMe)2(OMe)}(µ-dppm)M(Me)](Fe-M) (M ) Pd, Pt) react with ENtBuSiMe2NtBu (E )
Ge, Sn) by opening of the four-membered Fe-Si-O-M ring to give the complexes mer-
[(OC)3Fe{µ-Si(OMe)2(OMe)}{ENtBuSiMe2NtBu}{µ-dppm)M}(Me)](Fe-M) (5, M ) Pt, E )
Sn; 6, M ) Pd, E ) Sn; 7, M ) Pd, E ) Ge) which contain a five-membered Fe-Si-O-E-M
ring. The expected insertion of the amides ENtBuSiMe2NtBu into the M-Me bond was not
observed. The dynamic behavior of these intramolecularly base-stabilized trimetallic
germylene and stannylene complexes, which is due to a rapid exchange of the methoxy groups
coordinated on E, was investigated by variable-temperature 1H-NMR spectroscopy. All
complexes were characterized by multinuclear NMR spectroscopy, and the solid-state
structure of 7 was determined by X-ray diffraction.
In tr od u ction
mylenes and stannylenes have been shown to be very
versatile reagents toward transition metals2 and lead
to simple ligand substitutions,2f insertions into metal-
carbon bonds,2g,h or more complex reactions such as tin-
tin coupling in the tetrametallic chain complex [CpFe-
Heterodinuclear complexes containing a metal-metal
bond represent ideal molecules to study the influence
of different metal centers on their reactivity, including
chemo- and regioselectivity aspects. In addition to
metallosite-selective reactions, insertion into the metal-
metal bond may occur. It has been shown recently that
a Si(OR)3 group may display novel features in hetero-
metallic complexes which include hemilabile bridging
behavior,1a-e migration from one metal center to
another1a,f or to organic ligands,1a,h-i or transformation
into silylene species.1j On the other hand, cyclic ger-
(CO)2{SnNtBuSiMe2NtBu}]2.2g Assuming that poly-
(1) (a) Braunstein, P.; Knorr, M. In Metal Ligand Interactions;
Russo, N., Salahub, D. R., Eds.; Kluwer Academic Publishers: Dor-
drecht, The Netherlands, 1995; p 49. (b) Braunstein, P.; Knorr, M. In
Organosilicon Chemistry II; Auner, N., Weis, J ., Eds.; VCH: Weinheim,
Germany, 1996; p 553. (c) Braunstein, P.; Knorr, M.; Sta¨hrfeldt, T. J .
Chem. Soc., Chem. Commun. 1994, 1913. (d) Braunstein, P.; Faure,
T.; Knorr, M.; Sta¨hrfeldt, T.; DeCian, A.; Fischer, J . Gazz. Chim. Ital.
1995, 125, 35. (e) Braunstein, P.; Morise, X.; Blin, J . J . Chem. Soc.,
Chem. Commun. 1995, 1455. (f) Braunstein, P.; Knorr, M.; Hirle, B.;
Reinhard, G.; Schubert, U. Angew. Chem., Int. Ed. Engl. 1992, 31,
1583. (g) Braunstein, P.; Knorr, M. J . Organomet. Chem. 1995, 500,
21. (h) Knorr, M.; Braunstein, P.; DeCian, A.; Fischer, J . Organome-
tallics 1995, 14, 1302. (i) Knorr, M.; Braunstein, P.; Tiripicchio, A.;
Ugozzoli, F. Organometallics 1995, 14, 4910. (j) Bodensieck, U.;
Braunstein, P.; Deck, W.; Faure, T.; Knorr, M.; Stern, C. Angew. Chem.,
Int. Ed. Engl. 1994, 33, 2440.
† Dedicated to Prof. M. Herberhold on the occasion of his 60th
birthday with our sincere congratulations.
‡ Universita¨t des Saarlandes. E-mail addresses: m.knorr@
sbusol.rz.uni-sb.de and veith@sbusol.rz.uni-sb.de.
§ Universite´ Louis Pasteur. E-mail address: braunst@chimie.u-
strasbg.fr.
X Abstract published in Advance ACS Abstracts, August 1, 1996.
S0276-7333(96)00167-7 CCC: $12.00 © 1996 American Chemical Society

Reactions of Fe-Pt and Fe-Pd Complexes
Organometallics, Vol. 15, No. 18, 1996 3869
metallic systems associating such silicon and germanium/
tin centered ligands would exhibit interesting new
features, we envisaged to combine these two facets in a
collaborative approach.
{(MeO)3Si}Fe(µ-dppm)Rh(H)(Cl)](Fe-Rh) with carbon
monoxide.5a Similarly, elimination of HSi(OMe)3 was
observed upon reaction of [HFe{Si(OMe)3}(CO)3(η1-
dppm)] with fac-[Re(CO)3(THF)(µ-Br)]2 affording the
Here we report that metal(II) amides of the type
bromide-bridged complex [(OC)3Fe(µ-dppm)(µ-Br)Re-
(CO)3].5b In the present case, however, we found no
evidence by NMR or IR spectroscopy for the formation
of HSi(OMe)3 in the reaction mixture. We can also rule
out the formation of hexamethoxydisilane or tetrameth-
oxysilane, since the singlet resonance observed at δ 3.94
(in C6D6) does not correspond with their chemical shifts
(commercial samples). Therefore the mechanism of this
transformation remains still unclear.
ENtBuSiMe2NtBu (E ) Ge, Sn)2a,b can be used for the
systematic buildup of trimetallic compounds containing
both main group and transition metals with unprec-
edented dative interactions between Si(OMe)3 groups
and the metal amides.
Resu lts a n d Discu ssion
A. Com p lexes w ith a Br id gin g Sta n n ylen e or
Ger m ylen e Liga n d . Syn th esis. We began this study
with the bimetallic precursor complex [(OC)3{(MeO)3Si}-
Fe(µ-dppm)Pt(H)(PPh3)](Fe-Pt) (1), which contains a
terminal hydride ligand on platinum.3 We were inter-
ested to see whether treatment of 1 with a slight excess
A more rational access to 2 was provided by the
selective substitution of the bridging CO ligand of the
complexes [(OC)3Fe(µ-CO)(µ-dppm)Pt(PR3)](Fe-Pt) (R
) Ph, p-Tol)6 by SnNtBuSiMe2NtBu in toluene under
mild conditions (eq 2).
of SnNtBuSiMe2NtBu in toluene would substitute the
PPh3 ligand or insert into the Pt-H bond. Such
insertions of tin amides of the type [Sn{N(SiMe3)2}2] into
the M-H bonds of mononuclear complexes have previ-
ously been reported by Lappert and Rowe.4 However,
the outcome of this reaction was very surprising. IR
and 31P NMR monitoring of the course of the reaction
showed that all starting material had been consumed
after ca. 45 min, leading to the orange-red trimetallic
cluster [(OC)3Fe(µ-SnNtBuSiMe2NtBu)(µ-dppm)Pt(PPh3)]-
(Fe-Pt) (2a ) as the only observable phosphorus-contain-
ing species (eq 1). This compound has been fully
characterized by elemental analyses and multinuclear
NMR techniques (see below).
The orange red clusters 2a ,c have been isolated in
high yields and are air-stable for short periods of time.
In a similar manner, the yellow bis(diphenylphosphino)-
amine-bridged cluster 2b was obtained in 74% yield by
the reaction of [(OC)3Fe(µ-CO)(µ-dppa)Pt(PPh3)](Fe-Pt)7
with SnNtBuSiMe2NtBu. The replacement of the dppm
bridge by dppa in complex 2b lowers the stability both
in the solution and solid state, which may be due to a
slow reaction of the N-H group with the tin amide.2b
Note that, in contrast to the numerous examples of
dppm-bridged bi- and polymetallic complexes, only two
(3) (a) Braunstein, P.; Knorr, M.; Tiripicchio, A.; Tiripicchio-Camel-
lini, M. Angew. Chem., Int. Ed. Engl. 1989, 28, 1361. (b) Knorr, M.;
Faure, T.; Braunstein, P. J . Organomet. Chem. 1993, 447, C4.
(4) (a) Lappert, M. F.; Rowe, R. S. Coord. Chem. Rev. 1990, 100,
267. For other reviews dealing the chemistry of germylene and
stannylene complexes see: (b) Petz, W. Chem. Rev. 1986, 86, 1019. (c)
Holt, M. S.; Wilson, W. L.; Nelson, J . H. Chem. Rev. 1989, 89, 11. (d)
For a very recent example of an insertion of a germanium amide into
a Pt-H bond see: Litz, K. E.; Henderson, K.; Gourley, R. W.; Holl, M.
M. Organometallics 1995, 14, 5008.
(5) (a) Braunstein, P.; Knorr, M.; Villarroya, E.; DeCian, A.; Fischer,
J . Organometallics 1991, 10, 3714. (b) Knorr, M.; Braunstein, P.;
Tiripicchio, A.; Ugozzoli, F. J . Organomet. Chem., in press.
(6) Fontaine, X. L. R.; J acobsen, G. B.; Shaw, B. L.; Thornton-Pett,
M. J . Chem. Soc., Dalton Trans. 1988, 741.
Formal donor-induced reductive elimination of HSi-
(OMe)3 has occurred, a reaction previously observed
upon treatment of the related hydrido complex [(OC)3-
(2) (a) Veith, M. Angew. Chem. 1975, 87, 287. (b) Veith, M.; Grosser,
M. Z. Naturforsch. 1982, 37b, 1375. (c) Veith, M.; Lange, H.; Bra¨uer,
K.; Bachmann, R. J . Organomet. Chem. 1981, 216, 377. (d) Veith, M.;
Stahl, L.; Huch, V. Inorg. Chem. 1989, 28, 3278. (e) Veith, M. Angew.
Chem., Int. Ed. Engl. 1987, 26, 1. (f) Veith, M.; Stahl, L.; Huch, V. J .
Chem. Soc., Chem. Commun. 1990, 359. (g) Veith, M.; Stahl, L.; Huch,
V. Organometallics 1993, 12, 1914. (h) Veith, M.; Stahl, L. Angew.
Chem., Int. Ed. Engl. 1993, 32, 106. (i) Veith, M.; Mu¨ller, A.; Stahl,
L.; No¨tzel, M.; J arczyk, M.; Huch, V. Inorg. Chem. 1996, 35, 3848.
(7) Knorr, M. unpublished results, 1995.

3870 Organometallics, Vol. 15, No. 18, 1996
Knorr et al.
examples of dppa-bridged heterometallics have been
described in the literature, to the best of our knowledge.8
For comparison, we also examined the reactivity of
[(OC)3Fe(µ-CO)(µ-Ph2PXPPh2)Pt(PPh3)](Fe-Pt) toward
pounds 2 and 3. These ambivalent metal(II) amides
possess both a filled σ-donor orbital and a low-lying
empty p-orbital and can therefore act as σ-donor and/
or π-acceptor ligands.2d,e
the cyclic germanium(II) amide GeNtBuSiMe2NtBu.
Upon stoichiometric addition of this germylene re-
agent, substitution of the bridging CO ligand readily
occurred to afford the stable, yellow complexes [(OC)3Fe-
{µ-GeNtBuSiMe2NtBu}(µ-Ph2PXPPh2)Pt(PPh3)](Fe-
Pt) (3a , X ) CH2; 3b, X ) NH) in nearly quantitative
yields. Their spectroscopic data (see below) are very
It is known that the π-acceptor ability of σ-donor/
π-acceptor ligands like CO, CS, CNR, or SO2 generally
increases when these ligands are coordinated in a
bridging mode. We therefore conclude that it is the
electron-donating influence of the three phosphorus
ligands (combined with two transiton metals in low
oxidation states) which induces a bridging mode for the
the µ-[ENtBuSiMe2NtBu] ligands which can then better
evacuate electron density than in a terminal mode.
Sp ectr oscop ic Stu d ies. The structure of complexes
2 and 3 could be unambiguously deduced from the
combined NMR and IR data as exemplified below for
cluster 2a . The 31P{1H} NMR spectrum shows a doublet
of doublets at δ 83.6 for the iron-bound phosphorus
atom, which is strongly coupled (2+3J (P-P) ) 148 Hz)
with the platinum-bound dppm phosphorus, which is
found at δ 43.5. This signal is further split owing to
the presence of the PPh3 ligand which resonates at δ
41.9 as a doublet of doublets with a typical “cis-coupling”
of 13 Hz and a further weak 3+4J (P-P) coupling of 6
Hz with the dppm phosphorus on iron. All resonances
are flanked by 195Pt satellites with couplings of 80, 2841,
and 4491 Hz, respectively. Owing to the presence of
the bridging tin nucleus, all resonances show additional
sets of 119/117Sn satellites. These 2J (Sn-P) couplings are
also found in the 119Sn{1H} NMR spectrum, which
exhibits a ddd pattern centered at δ 615.1. The PPh3
ligand is only weakly coupled by ca. 45 Hz, whereas the
two dppm phosphorus nuclei, which are in a transoid
position with respect to tin, are coupled by ca. 130 and
1373 Hz. The 31P{1H} NMR spectrum of 2c is very
similar and is depicted in Figure 1. On the basis of the
very different 2J (P2-Sn) and 2J (P3-Sn) coupling con-
stants, one could anticipate that the tin amide ligand
bridges the Fe-Pt bond in an unsymmetrical manner,
with the larger value being associated with a shorter
Pt-(µ-Sn) distance. However, the almost symmetrically
bridging position of the carbene ligand in the related
µ-siloxycarbene complex [(OC)3Fe{µ-C(Et)OSi(OMe3)}-
similar to their tin congeners. Therefore, we assume 3
to be isostructural with 2. In the trimetallic cores of 2
and 3, the three metal centers are mutually connected
by metal-metal bonds, conferring to the Pt and Fe
centers their usual 16 and 18 e count, respectively.
No reaction took place when the lead(II) amide
PbNtBuSiMe2NtBu was mixed with [(OC)3Fe(µ-CO)(µ-
dppm)Pt(PPh3)](Fe-Pt). However, plumbylene-bridged
clusters have been prepared very recently by the reac-
tion of [Ru3(CO)12] with [Pb{CH(SiMe3)}2].9
Cluster compounds in which metal(II) amides or
related tin species bridge two identical transition metals
to form a triangular core were already known. Ex-
amples include [(M{µ-E(NR2)2}}CO)3] (M ) Pd, Pt; R )
SiMe3),10a,b [(PPh3)Pt{µ-Sn(acac)2}3Pt(PPh3)],10c [(Ru3-
(µ-SnR2)2(CO)10],10d and [(PPh3)Pd{µ-SnNtBuSiMe2N-
tBu}3Pd(PPh3)].2i Compounds 2 and 3 extend this class
of mixed main group-transition metal clusters and
represent the first examples where a germylene or
stannylene unit bridges different metals connected by
a metal-metal bond. A related Fe-Sn-Pt array was
recently established in the µ-SnCl2 complex [(OC)3-
{(MeO)3Si}Fe(µ-dppm)(µ-SnCl2)Pt(Cl)(PEt3)],11 although
in this case there was no metal-metal bond between
the Pt and Fe centers.
2
(µ-dppm)Pt(PPh3)](Fe-Pt) is associated with J (P-µ-C)
One may ask why the germylene or stannylene
ligands exclusively adopt a bridging position in com-
couplings of 14 and 84 Hz.1h By analogy, we therefore
assume a rather symmetric bridging position of the tin
center between the two transition metals.
(8) (a) Blagg, A.; Cooper, G. R.; Pringle, P. G.; Robson, R.; Shaw, B.
L. J . Chem. Soc., Chem. Commun. 1984, 933. (b) Uson, R.; Fornies, J .;
Navarro, R.; Cebollada, J . I. J . Organomet. Chem. 1986, 304, 381. (c)
Witt, M.; Roesky, H. W. Chem. Rev. 1994, 94, 1163. (d) Mague, T. J .
J . Cluster Sci. 1995, 6, 217.
(9) Burton, N. C.; Cardin, C. J .; Cardin, D. J .; Twamley, B.;
Zubavichus, J . Organometallics 1995, 14, 5708.
(10) (a) Hitchcock, P. B.; Lappert, M. F.; Misra, M. C. J . Chem. Soc.,
Chem. Commun. 1985, 863. (b) Campbell, G.; Hitchcock, P. B.; Lappert,
M. F.; Misra, M. C. J . Organomet. Chem. 1985, 289, C1. (c) Bushnell,
G. W.; Eadie, D. T.; Pidcock, A.; Sam, A. R.; Holmes-Smith, R. D.;
Stobart, S. R.; Brennan, E. T.; Cameron, T. S. J . Am. Chem. Soc. 1982,
104, 5837. (d) Cardin, C. J .; Cardin, D. J .; Lawless, G. A.; Power, J .
M.; Hursthouse, M. B. J . Organomet. Chem. 1987, 325, 203.
(11) Braunstein, P.; Knorr, M.; Strampfer, M.; Tiripicchio, A.;
Ugozzoli, F. Organometallics 1994, 13, 3038.
A ddd pattern is found in the 195Pt{1H} NMR spec-
1
trum of 2a . This signal at δ -3188 displays J (Pt-P)
couplings of 2840 Hz (dppm) and 4490 Hz (PPh3) and a
2+3J (Pt-P) coupling of 79 Hz with the iron-bound
1
phosphorus. In addition, a J (Pt-Sn) coupling of 9708
Hz is observed. In the 13C{1H} NMR spectra two
doublets are observed for the inequivalent iron carbo-
nyls in a 1:2 ratio at δ 220.1 (see Experimental Section)
1
and 210.8. Both in the 13C and H NMR spectrum the
SiMe2 groups appear as two distinct signals due to the
bridging bonding mode of the tin atom.

Reactions of Fe-Pt and Fe-Pd Complexes
Organometallics, Vol. 15, No. 18, 1996 3871
3b. Attempts to obtain a bis(stannylene) complex
remained unsuccessful. Even on addition of a further
2 equiv of [Sn(NtBu)2SiMe2] to a solution of 2a and
gentle heating, only 2a was recovered. Upon addition
of a second 1 equiv of germylene to a toluene solu-
tion of 3a , 31P NMR monitoring revealed partial sub-
stitution of the PPh3 ligand with formation of the
bis(germylene) complex [(OC)3Fe{µ-GeNtBuSiMe2N-
tBu}(µ-dppm)Pt{GeNtBuSiMe2NtBu}] (4) (eq 3).
F igu r e 1. 31P{1H} NMR spectrum of [(OC)3Fe(µ-dppm)-
{µ-SnNtBuSiMe2NtBu}Pt{P(p-tol)3}](Fe-Pt) (2c). The as-
terisks denote the 117/119Sn satellites.
In the 31P{1H} NMR spectrum of the dppa-bridged
derivative 2b the resonances of the dppa ligand are
significantly shifted to lower field. The doublet at δ
122.1 is assigned to the iron-bound phosphorus atom,
which is strongly coupled (2+3J (P-P) ) 173 Hz) with
the platinum-bound dppa phosphorus at δ 92.6. This
signal is further split owing to the presence of the PPh3
ligand. This latter gives rise to a doublet at δ 41.5 with
a cis-coupling of 28 Hz. Whereas the 1J (Pt-P1) coupling
for the platinum-bound PPh3 ligand is similar to that
The existence of an equilibrium between 3a and 4 is
indicated in 31P{1H} NMR by a broad resonance at δ
-4.5 due to PPh3 in rapid exchange with 3a . This
equilibrium can be shifted completely to the right side
1
in 2a (4506 vs 4491 Hz), the J (Pt-P2) coupling for the
platinum-bound dppa phosphorus is however markedly
increased (3235 vs 2841 Hz for 2a ). The chemical shift
of the 195Pt nucleus (δ -3260) is not much affected by
the nature of the bridging phosphine backbone and
appears as a doublet of doublets of doublets with
coupling constants of 68, 3235, and 4505 Hz. The NMR
data of the dppa-bridged germylene homologue 3b are
very similar (see Experimental Section).
using a 5-fold excess of GeNtBuSiMe2NtBu. However,
attempts to isolate pure 4 failed since 3a was recovered
when excess GeNtBuSiMe2NtBu was removed. We tried
also to trap the phosphine by CH3I; however, a complex
mixture of unknown compounds was obtained. The 31P-
{1H} NMR spectrum of 4 exhibits a AX pattern centered
at δ 78.3 and δ 46.5 for the iron-bound and platinum-
bound phosphorus atoms, respectively (2+3J (P-P) ) 150
Hz). The observation of both a 2+3J (Pt-P) of 86 Hz and
The IR spectra of 2 and 3 show three distinct ν(CO)
vibrations, as expected for a meridional arrangement
of these ligands. The position of these bands is not
much influenced by the nature of the bridging Sn or Ge
ligand. However, a significant shift to higher wave-
numbers is observed for the dppa-bridged derivatives
2b and 3b, which may be caused by a lower electron
donating ability of the dppa backbone. The solid-state
IR spectra of 2b and 3b contain a sharp absorption
1
a J (Pt-P) of 2871 Hz supports our assumption that a
Fe-Pt bond is preserved.
B. Com p lexes w ith a Cyclic Str u ctu r e. The
versatility of these cyclic metal(II) amide reagents2
led us to consider their reactivity toward heterobime-
tallic alkyl complexes of the type [(OC)3Fe(µ-Si{OMe)2-
assigned to the N-H vibration (3309 and 3318 cm-1
)
(OMe)}(µ-dppm)M(Me)](Fe-M) (M ) Pd, Pt), related to
1 but in which the Si(OMe)3 ligand is bridging between
the metals.1a,b The stability of the resulting four-
which is indicative for the absence of hydrogen bonds,
otherwise often encountered in dppa complexes.12
Rea ctivity Stu d ies. Reaction of 2a with 1 equiv of
2,6-dimethylphenyl isocyanide led to quantitative dis-
placement of the tin amide to afford the known isocya-
nide-bridged complex [(OC)3Fe{µ-CN-xylyl}(µ-dppm)-
membered cycle Fe-Si-OfM is associated with a
lability of the dative OfM interaction. This confers a
unique hemilabile character to the Si(OMe)3 ligand and
plays a central role for e.g. the migratory insertion of
small molecules like isocyanides, CO, and olefins1c,d into
the metal-alkyl bond or the catalytic dehydrogenative
coupling of stannanes.1e
Pt(PPh3)](Fe-Pt).3b Interestingly, GeNtBuSiMe2NtBu
substitutes the bridging benzyl isonitrile ligand of
[(OC)3Fe{µ-CN-benzyl}(µ-dppa)Pt(PPh3)](Fe-Pt)7 to give
(12) (a) Liehr, G.; Szucsanyi, G.; Ellermann, J . J . Organomet. Chem.
1984, 265, 95. (b) Steil, P.; Nagel, U.; Beck, W. J . Organomet. Chem.
1989, 366, 313.
Insertion of the reactive metal amides ENtBuSiMe2N-
tBu into the M-C σ-bond was therefore anticipated,

3872 Organometallics, Vol. 15, No. 18, 1996
Knorr et al.
Ta ble 1. Selected Bon d Dista n ces (Å) a n d An gles
(d eg) for Com p lex 7
Pd(1)-Ge(1)
Pd(1)-Fe(1)
Ge(1)-O(1)
Fe(1)-Si(1)
Fe(1)-P(2)
2.36(5)
2.74(6)
2.10(2)
2.26(12)
2.23(11)
Pd(1)-P(1)
Pd(1)-C(1)
Si(1)-O(1)
Si(1)-O(2)
Si(1)-O(3)
2.31(9)
2.10(3)
1.70(2)
1.64(3)
1.65(4)
Pd(1)-Fe(1)-Si(1)
Fe(1)-Si(1)-O(1)
Si(1)-O(1)-Ge(1)
96.8(3)
115.1(8)
P(2)-Fe(1)-Pd(1)
P(1)-Pd(1)-Fe(1)
95.3(3)
92.0(2)
124.2(11) P(1)-Pd(1)-Ge(1) 169.2(3)
Pd(1)-Ge(1)-O(1) 104.2(6)
C(1)-Pd(1)-Ge(1) 81.9(9)
P(2)-Fe(1)-Si(1)
167.2(5)
Si(OMe)2(OMe)}{SnNtBuSiMe2NtBu(µ-dppm)Pt}(Me)]-
(Fe-Pt) (5). The meridional arrangement of the carbo-
nyls is retained, but a shift of the three ν(CO) vibrations
(1947 m, 1884 s, 1848 s) of ca. 10 cm-1 to lower
wavenumbers results from insertion of the stannylene.
The electron-donating effect of the metal amides ap-
pears to be larger than their back-bonding abilities. The
31P{1H} NMR data are consistent with this structure
(see Experimental Section). In the 195Pt{1H} NMR
spectrum, the dd resonance at δ -2825 shows the
expected 1J (Pt-117/119Sn) couplings in the range of
16 634 and 17 430 Hz, respectively. Compared to the
low-field 119Sn chemical shifts of ca. 600 ppm for the
µ-stannylene complexes 2a ,c, the 119Sn chemical shifts
of 5 and 6 are dramatically high-field shifted at δ 128.7
for 5 and δ 81.2 for 6.
Proton NMR spectroscopy of 5-7 at variable temper-
atures revealed rapid exchange of the methoxy groups.
For 5, a sharp singlet for the Si(OMe)3 ligand is ob-
served at δ 3.70, which broadens on lowering the temp-
erature, whereas the other signals remained unaffected.
Coalescence was reached at 255 K. Below this temper-
ature, the methoxy resonance gives two distinct signals
which are found in a 1:2 ratio at 233 K at δ 3.87 and
3.57, indicating the presence of a rigid five-membered
F igu r e 2. Perspective view and numbering scheme for
mer-[(OC)3Fe{µ-Si(OMe)2(OMe)}{GeNt BuSiMe2Nt Bu}-
(µ-dppm)Pd(Me)](Fe-Pd) (7).
by analogy also with their insertion into the Fe-Me
bond of [CpFe(CO)2Me], which yielded [CpFe(CO)2-
{ENtBuSiMe2NtBu}Me].2g However, on the basis of the
spectroscopic data, insertion of ENtBuSiMe2NtBu (E )
Ge, Sn) into the M-methyl bond of [(OC)3Fe(µ-Si-
{OMe)2(OMe)}(µ-dppm)M(Me)](Fe-M) (M ) Pd or Pt)
was ruled out, even in the presence of excess reagent
and after long reaction times. Instead the trimetallic
stannylene or germylene adducts 5-7 were formed in
high yields: the reagent has inserted into the dative
OfM bond to form an unprecedented five-membered
ring structure (eq 4). Again, no reaction took place with
the plumbylene PbNtBuSiMe2NtBu reagent.
Fe-Si-OfSn-Pt cycle. Using the Eyring equation, we
estimate for 5 a ∆Gq of 51.3 kJ /mol and for the
palladium derivatives 6 and 7 a ∆Gq of 53.6 and 54.7
kJ /mol, respectively. This intramolecular base stabili-
zation may also be responsible for the fact that no in-
sertion reaction into the M-methyl bond was observed.
One may speculate about the validity of a bonding
description of complexes 5-7 with a silylene-like bond-
ing of the silyl moiety, base-stabilized by a bridging
methoxy group. Such a formalism has been used by
Ogino et al. to describe the molecular structure of the
fluxional complex [(η-C5Me5)Fe(CO)GeMe2OMeSiMe2],
for which rotation about the Fe-Ge bond has been
deduced from NMR experiments.13
An X-ray diffraction study was performed on a single
crystal of 7 (Figure 2). Unfortunately, extensive de-
composition occurred during the data collection, and due
to the insufficient data quality, we will not discuss the
structural features in detail. Selected bond lengths and
angles are listed in Table 1. The structure shown is
consistent with IR and multinuclear NMR data at
variable temperatures, as exemplified for [(OC)3Fe-{µ-
We confidently rule out this description for our com-
pounds which involves rotation around the M-E axis.
In the temperature range examined we always observed

Reactions of Fe-Pt and Fe-Pd Complexes
Organometallics, Vol. 15, No. 18, 1996 3873
R3-11 catalyst and P4O10 columns to remove residual oxygen
or water. Elemental C, H, and N analyses were performed
on a Leco CHN 900 elemental analyzer. Infrared spectra were
recorded in the 4000-400 cm-1 region on Perkin-Elmer 883
spectrometer. The 1H, 31P{1H}, 119Sn{1H}, 29Si-INEPT, and
13C{1H} NMR spectra were recorded at 200.13, 81.01, 74.60,
39.76, and 50.32 MHz, respectively, on a Bruker ACP 200
instrument. Phosphorus chemical shifts were referenced to
85% H3PO4 in water and 119Sn chemical shifts to SnMe4 with
downfield shifts reported as positive. 195Pt chemical shifts
were measured on a Bruker ACP 200 instrument (42.95 MHz)
and externally referenced to K2PtCl4 in water with downfield
chemical shifts reported as positive. Unless otherwise stated,
NMR spectra were recorded in pure CDCl3. The reactions
were generally monitored by IR in the ν(CO) region. The
presence of 0.5 molecules of toluene in 2a ,b has been deter-
mined from the 1H NMR spectrum.
two distinct resonances for the nonequivalent Si-CH3
groups, which should become identical if the above
mechanism were operative. Furthermore, the 29Si NMR
chemical shift for the Si(OMe)3 group of 7 (δ 29.4) is in
the usual range for M-Si(OMe)3 complexes (e.g. δ(29Si)
17.6 for [(OC)3Fe(µ-Si{OMe)2(OMe)}(µ-dppm)Pd(Me)]-
(Fe-Pd)), whereas that for [η-C5Me5)Fe(CO)GeMe2-
OMe-SiMe2] appears in the low-field region at δ 114.3.34
As noticed above for the ENtBuSiMe2NtBu-bridged
clusters 2 and 3, the germylene derivative 7 is more
stable than the stannylene analogues 5 and 6. Upon
standing in solution, the latter gradually loose the tin
amide ligand to regenerate [(OC)3Fe(µ-Si{OMe)2(OMe)}-
[(OC)3F e (µ-Sn Nt Bu SiMe 2Nt Bu ))(µ-d p p m )P t (P P h 3)]-
(µ-dppm)M(Me)](Fe-M), whereas the germylene com-
plex 7 remained unchanged after 2 days in CDCl3. This
may explain our failure to get correct elemental analyses
for 5 and 6.
(C) At t em p t ed P r ep a r a t ion of F e-R h St a n -
n ylen e a n d Ger m ylen e Com p lexes. We then tried
to extend the observations made in eq 4 to a related
Fe-Rh complex containing a four-membered ring
(Fe-P t) (2a ). Meth od A. SnNtBuSiMe2NtBu (0.21 mmol,
56 µL) was added slowly to a suspension of [(OC)3{(MeO)3Si}-
Fe(µ-dppm)Pt(H)(PPh3)] (1) (220 mg, 0.2 mmol) in C6D6 (2 mL)
at room temperature. The resulting deep red solution was
stirred for 45 min. 31P NMR-monitoring showed the presence
of 2a as the only P-containing species in solution. Layering
the solution with hexane afforded 2a in form of orange-yellow
microcrystals (0.161 g, 63%).
Fe-Si-OfRh.5a Surprisingly, no reaction took place
Meth od B. A solution of SnNtBuSiMe2NtBu (0.55 mmol,
160 µL) in toluene (5 mL) was added slowly to a stirred
suspension of [(OC)3Fe(µ-dppm)(µ-CO)Pt(PPh3)](Fe-Pt) (505
mg, 0.5 mmol) in toluene (10 mL) at room temperature. The
clear red mixture was stirred for 15 min and then evaporated
under reduced pressure to ca. 4 mL. Addition of hexane
yielded 2a as an orange-yellow powder (0.620 g, 92%). (Anal.
Found: C, 52.81; H, 4.46; N, 1.50. Calc for C56H61N2O3P3-
FePtSiSn‚0.5C7H8 (M ) 1300.76 + 46.07): C, 53.06; H, 4.86;
N, 2.08). IR (toluene): ν(CO) 1955 m, 1908 s, 1873 s cm-1. 1H
NMR: δ 0.34 (s, 3H, SiMe), 0.43 (s, 3H, SiMe), 0.99 (s, 18H,
tBu), 3.32 (t, 2H, PCH2P, 2J (P-H) ) 9.6, 3J (Pt-H) ) 38), 7.08-
7.38 (m, 35H, C6H5). 31P{1H} NMR: δ 41.9 (dd, P1(Pt), 2J (P1-
P2) ) 13, 3+4J (P1-P3) ) 6, 1J (P-Pt) ) 4491, 2J (P-Sn) ) 130),
when [(OC)3Fe(µ-Si{OMe)2(OMe)}(µ-dppm)Rh(PPh3)](Fe-
Rh) was reacted with an excess of ENtBuSiMe2NtBu.
Even after gentle heating, only the starting materials
were recovered. Although stable complexes with Rh-
Sn and Rh-Ge bonds have recently been reported from
the reactions of [RhCl(PPh3)3] with ENtBuSiMe2NtBu,2d,i
the strength of the dative MeOfRh interaction appears
to prevent adduct formation under ring opening, as
found for the related systems 5-7.
Con clu sion
2
1
43.5 (dd, P2(Pt), J (P2-P1) ) 13, 2+3J (P2-P3) ) 148, J (P-Pt)
) 2841, 2J (P-Sn) ) 1373), 83.6 (dd, P3(Fe), 2+3J (P3-P2) ) 148,
3+4J (P3-P1) ) 6, 2+3J (P-Pt) ) 80, 2J (P-Sn) ) 43). 13C{1H}
We have shown that heterotrimetallic clusters con-
taining both main group and transition metals are
obtained in high yields by reaction of cyclic bis(amino)-
germylenes and -stannylenes with heterobimetallic
complexes. The amides adopt exclusively a bridging
bonding mode in the clusters 2 and 3 and a terminal
base-stabilized bonding mode in complexes 5-7. These
heterotrimetallic systems are not reactive (under mild
conditions) toward displacement of other ligands, e.g.
CO or PPh3. Future work using more severe reaction
conditions or photochemical activation will be required
to see whether these compounds can be used for the
construction of higher nuclearity clusters. Another
aspect which deserves further investigation is the
possibility to chemically transform the coordinated
metal amides. The present findings demonstrate again
the diversity of reaction patterns that may be observed
when polymetallic systems are reacted with low-valent
main group compounds.
5
NMR (253 K): δ 7.0 (d, 1C, SiMe, J (P-C) ) 2.6), 8.8 (s, 1C,
SiMe), 34.8 (s, 6C, C-Me), 51.2 (s, 2C, N-C), 125.2-136.6 (m,
42C, C6H5), 210.8 (d, 2C, CO, 2J (P-C) ) 24), 220.1 (d, 1C, CO,
4
2J (P-C) ) 8). 29Si-INEPT NMR: δ 3.35 (d, SiMe2, J (P2-Si)
) 2). 119Sn{1H} NMR: δ 615.1 (ddd, 2J (Sn-P1) ) 132, 2J (Sn-
2
P2) ) 1373, J (Sn-P3) ) 50). 195Pt{1H} NMR: δ -3188 (ddd,
1J (Pt-P1) ) 4491, 1J (Pt-P2) ) 2841, 2+3J (Pt-P3) ) 79, 1J (Pt-
119Sn) ) 9708 Hz).
[(O C )3F e (µ-S n N t B u S iMe 2N t B u )(µ-d p p a )P t (P P h 3)]-
(Fe-P t) (2b). The yellow cluster 2b was prepared similarly
to 2a (method B), using SnNtBuSiMe2NtBu (0.55 mmol, 160
µL) and [(OC)3Fe(µ-CO)(µ-dppa)Pt(PPh3)](Fe-Pt) (0.5 mmol,
505 mg) (prepared from [Fe(CO)4(η1-dppa)] and [Pt(H2CdCH2)-
(PPh3)2]. Yield: 0.498 g, 74%. (Anal. Found: C, 51.93; H,
4.92; N, 2.98. Calc for C55H60N3O3P3FePtSiSn‚0.5C7H8 (M )
1301.75 + 46.07): C, 52.13; H, 4.92; N, 2.98). IR (toluene):
ν(CO) 1964 m, 1913 s, 1893 s. IR (KBr): ν(CO) 1956 m, 1912
sh, 1891 s, ν(NH) 3309 w cm-1 1H NMR: δ 0.33 (s, 3H, SiMe),
.
0.41 (s, 3H, SiMe), 0.92 (s, 18H, tBu), 4.70 (t br, 1H, NH, 3J (Pt-
H) ) 86.0), 7.08-7.44 (m, 35H, C6H5). 31P{1H} NMR: δ 41.5
Exp er im en ta l Section
2
1
(d, P1(Pt), J (P-P2) ) 28, J (P-Pt) ) 4506), 92.6 (dd, P2(Pt),
All reactions were performed in Schlenk-tube flasks under
purified nitrogen. Solvents were dried and distilled under
nitrogen before use, with tetrahydrofuran over sodium ben-
zophenone ketyl, toluene and hexane over sodium, and dichlo-
romethane from P4O10. Nitrogen was passed through BASF
(13) (a) Koe, J .; Tobita, H.; Ogino, H. Organometallics 1992, 11,
2479. (b) For a very recent example of a mononuclear tungsten silyl
germylene see: Figge, L. K.; Carroll, P. J .; Berry, D. H. Organometallics
1996, 15, 209.

3874 Organometallics, Vol. 15, No. 18, 1996
Knorr et al.
1
2J (P-P1) ) 28, 2+3J (P-P3) ) 173, J (P-Pt) ) 3235), 122.1 (d,
630 mg) in 10 mL of toluene was added dropwise a solution of
P3(Fe), 2+3J (P-P2) ) 173, 2+3J (P-Pt) ) 68, 2J (P-Sn) ) 40).
GeNtBuSiMe2NtBu (2.0 mmol, 540 µL) in 5 mL of toluene
within 30 min. The clear orange yellow solution was stirred
for 15 min and then examined by spectroscopic methods.
Attempts to isolate pure 4 always led to mixtures containing
both 4 and 3a . IR (toluene): ν(CO) 1961 m, 1910 s, 1878 m
195Pt {1H} NMR: δ -3260 (ddd, J (P1-Pt) ) 4506, J (P2-Pt)
1
1
) 3235, 2+3J (P3-Pt) ) 68 Hz).
[(OC)3F e(µ-Sn NtBu SiMe2NtBu )(µ-d p p m )P t{P (p-tol)3}]-
(Fe-P t) (2c). To a suspension of [(OC)3Fe(µ-CO)(µ-dppm)Pt-
{P(p-tol)3}] (0.5 mmol, 525 mg) in toluene (10 mL) was added
cm-1 31P{1H} NMR (C6D6/toluene): δ 46.5 (d, P1(Pt), 2+3J (P-
.
1 2
P) ) 150, J (P-Pt) ) 2871), 78.3 (d, P2(Fe), J (P-Pt) ) 86).
195Pt{1H} NMR (C6D6/toluene): δ -3301 (dd, 1J (P1-Pt) ) 2871,
2+3J (P2-Pt) ) 86 Hz).
dropwise a solution of SnNtBuSiMe2NtBu (0.55 mmol, 160 µL)
in toluene (5 mL) within 5 min. The clear red mixture was
stirred for 15 min, and then the solvent was reduced under
vacuum to 4 mL. Addition of hexane yielded 2c as a red
powder (0.632 g, 91%). (Anal. Found: C, 54.03; H, 5.84; N,
1.88. Calc for C59H67N2O3P3FePtSiSn‚0.5C7H8 (M ) 1342.84
+ 46.07): C, 54.05; H, 5.13; N, 2.02). IR (toluene): ν(CO):
1956 m, 1907 s, 1871 m. 1H NMR: δ 0.32 (s, 3H, SiMe), 0.43
[(O C )3 F e {µ-S i(O Me )2 (O Me )}(S n N t B u S iMe 2 N t B u }-
(Me)](Fe-P t) (5). To a suspension of [(OC)3Fe{µ-Si(OMe)2-
(OMe)}(µ-dppm)Pt(Me)](Fe-Pt) (0.5 mmol, 430 mg) in 10 mL
of Et2O was added dropwise a solution of SnNtBuSiMe2NtBu
(0.55 mmol, 150 µL) in 2 mL of toluene. The reaction mixture
was stirred at room temperature for 1 h. 31P-NMR monitoring
revealed that 5 was the sole P-containing species in solution.
Reduction of the volume to ca. 6 mL and addition of hexane
yielded 5 as a yellow powder, which was washed with hexane
and dried under vacuum. 31P-NMR analysis of the yellow
powder revealed that after removal of all volatiles ca. 15% of
the starting material has been re-formed by partial stannylene
t
(s, 3H, SiMe), 1.01 (s, 18H, Bu), 2.28 (s, 9H, tolyl-Me), 3.30
(t, 2H, PCH2P, 2J (P-H) ) 9.5, 3J (Pt-H) ) 38), 6.87-7.41 (m,
32H, C6H5). 31P{1H} NMR: δ 39.5 (dd, P1(Pt), 2J (P1-P2) )
13, 3+4J (P1-P3) ) 6, J (P-Pt) ) 4490, J (P-Sn) ) 130), 43.0
(dd, P2(Pt), 2+3J (P2-P3) ) 149, 2J (P2-P1) ) 13, 1J (P-Pt) )
2841, 2J (P-Sn) ) 1383), 83.2 (dd, P3(Fe), 3+4J (P3-P1) ) 6,
1
2
2+3J (P3-P2) ) 149, 2+3J (P-Pt) ) 79, J (P-Sn) ) 36). 119Sn-
2
{1H} NMR: δ 608.2 (ddd, 2J (P1-Sn) ) 132, 2J (P2-Sn) ) 1383,
2J (P3-Sn) ) 36). 195Pt{1H} NMR: δ -3182.1 (ddd, 1J (P1-Pt)
dissociation. IR (toluene): ν(CO) 1947 s, 1884 s, 1848 s cm-1
.
) 4490, J (P2-Pt) ) 2841, J (P-Pt) ) 79 Hz).
1
2
1H NMR: δ 0.19 (s, 3H, SiMe), 0.23 (s, 3H, SiMe), 0.40 (d, 3H,
PtMe, 3J (P-H) ) 8.5, 2J (Pt-H) ) 55), 1.11 (s, 18H, tBu), 3.45
[(OC)3F e (µ-Ge Nt Bu SiMe 2Nt Bu )(µ-d p p m )P t (P P h 3)]-
(Fe-P t) (3a ). It was prepared similarly to 2a (method B),
2
3
(t, 2H, PCH2P, J (P-H) ) 10.4, J (Pt-H) ) 43), 3.69 (s, 9H,
Si(OMe)3), 7.15-7.58 (m, 20H, C6H5), 31P{1H} NMR: δ 32.0
(d, P1(Pt-P), 2+3J (P1-P2) ) 102, 1J (P-Pt) ) 3513, 2J (P-
117Sn) ) 3498, 2J (P-119Sn) ) 3576), 71.3 (d, P2(Fe-P), 2+3J (P-
Pt) ) 50, 3+4J (P-Sn) ) 212). 29Si-INEPT NMR: δ 3.05 (d,
SiMe2, 4J (P1-Si) ) 2), 26.9 (dd, Si(OMe)3, 2J (Si-P2) ) 38,
4J (Si-P1) ) 4). 119Sn{1H} NMR: δ 128.6 (dd, 2J (P1-Sn) )
3571, 3+4J (P2-Sn) ) 219, 1J (Pt-Sn) ) 17376). 195Pt{1H}
NMR: δ -2825 (dd, 1J (P1-Pt) ) 3513, 2+3J (P2-Pt) ) 50,
using GeNtBuSiMe2NtBu (0.6 mmol, 100 µL) and [(OC)3Fe(µ-
CO)(µ-dppm)Pt(PPh3)](Fe-Pt) (0.5 mmol, 505 mg), and isolated
in the form of yellow microcrystals (0.546 g, 87%). (Anal.
Found: C, 54.00; H, 5.45; N, 2.16. Calc for C56H61N2O3P3-
FePtSiGe (M ) 1254.66): C, 53.61; H, 4.90; N, 2.23). IR
(toluene): ν(CO) 1960 m, 1910 s, 1872 s. IR (KBr): ν(CO) 1958
m, 1897 s, 1871 s cm-1 1H NMR: δ 0.42 (s, 3H, SiMe), 0.49
.
t
2
(s, 3H, SiMe), 0.98 (s, 18H, Bu), 3.21 (t, 2H, PCH2P, J (P-H)
1
1J (Pt-117Sn) ) 16634, J (Pt-119Sn) ) 17430 Hz).
) 9.1, J (Pt-H) ) 33.5), 7.05-7.28 (m, 35H, C6H5). 31P{1H}
3
NMR: δ 39.6 (dd, P1(Pt), 2J (P1-P2) ) 13, 3+4J (P1-P3) )
6, 1J (P-Pt) ) 4534), 42.4 (dd, P2(Pt), 2+3J (P2-P3) ) 149,
2J (P2-P1) ) 13, 1J (P-Pt) ) 2419), 81.6 (dd, P3(Fe), 2+3J -
(P3-P2) ) 149, 3+4J (P3-P1) ) 6, 2+3J (P-Pt) ) 91). 13C{1H}
NMR: δ 5.6 (d, 1C, SiMe), 8.2 (s, 1C, SiMe), 33.6 (s, 6C, C-Me),
51.8 (s, 2C, N-C), 127.8-134.6 (m, 42C, C6H5), 214.1 (d, 2C,
CO, 2J (PC) ) 27), 220.7 (d, 1C, CO, 2J (PC) ) 7). 195Pt{1H}
NMR; δ -3125 (ddd, 1J (P1-Pt) ) 4534, 1J (P2-Pt) ) 2419,
2+3J (P3-Pt) ) 91 Hz).
[(OC)3F e {µ-Si(OMe )2(OMe )}{Sn Nt Bu SiMe 2Nt Bu }(µ-
d p p m )P d (Me)](Fe-P d ) (6). To a suspension of [(OC)3Fe{µ-
Si(OMe)2(OMe)}(µ-dppm)Pd(Me)](Fe-Pd) (1.0 mmol, 768 mg)
in diethyl ether (15 mL) was added dropwise SnNtBuSiMe2Nt-
Bu (1.1 mmol, 300 µL). The reaction mixture was stirred at
room temperature for 1 h, and then the volume was reduced
to 6 mL. Addition of hexane yielded 6 as a red orange powder,
which was washed with hexane and dried under vacuum. IR
(KBr): ν(CO) 1949 s, 1885 s, 1858 s, ν(SiOCH) 2840 w. IR
[(O C )3F e (µ-G e N t B u S iMe 2N t B u )(µ-d p p a )P t (P P h 3)]-
(Fe-P t) (3b). This complex was prepared similarly to 2a
(Et2O): ν(CO) 1954 m, 1894 s, 1864 s cm-1
.
1H NMR: δ 0.25
3
(s, 3H, SiMe), 0.28 (s, 3H, SiMe), 0.33 (d, 3H, PdMe, J (P-H)
) 8.3), 1.22 (s, 18H, tBu), 3.53 (t, 2H, PCH2P, 2J (P-H) ) 10.4),
3.75 (s, 9H, Si(OMe)3), 7.19-7.53 (m, 20H, C6H5). 31P{1H}
(method B), using GeNtBuSiMe2NtBu (0.6 mmol, 100 µL) and
[(OC)3Fe(µ-CO)(µ-dppa)Pt(PPh3)](Fe-Pt) (0.5 mmol, 505 mg),
and isolated as a yellow microcrystalline powder (0.521 g,
83%). (Anal. Found: C, 52.55; H, 4.49; N, 2.95. Calc for
NMR: δ 32.25 (d, P1(Pd-P), 2+3J (P1-P2) ) 113, J (P-117Sn)
2
) 3417, 2J (P-119Sn) ) 3550), 70.9 (d, P2(Fe-P), 3+4J (P-Sn) )
195). 29Si-INEPT NMR: δ 2.68 (d, SiMe2, 4J (Si-P1) ) 1.9,
C
55H60N3O3P3FePtSiGe (M ) 1255.65): C, 52.61; H, 4.82; N,
2
4
2J (Si-Sn) ) 23.6), 26.8 (dd, SiOMe, J (P2-Si) ) 34.1, J (P2-
Si) ) 3.6). 119Sn{1H} NMR: δ 81.2 (dd, 2J (P1-Sn) ) 3554,
3+4J (P2-Sn) ) 197 Hz).
3.35). IR (toluene): ν(CO) 1968 m, 1915 s, 1894 s. IR (KBr):
ν(CO) 1966 m, 1912 sh, 1892 s, ν(NH) 3318 w cm-1
.
1H NMR:
t
δ 0.45 (d, 3H, SiMe), 0.50 (s, 3H, SiMe), 0.95 (s, 18H, Bu),
4.58 (t br, 1H, PNHP, 2J (H-P) ) 79), 7.04-7.43 (m, 35H,
C6H5). 31P{1H} NMR: δ 39.3 (d, P1(Pt), 2J (P1-P2) ) 29, 1J (P1-
[(OC)3F e {µ-Si(OMe )2(OMe )}{Ge Nt Bu SiMe 2Nt Bu }(µ-
d p p m )P d (Me)](F e-P d ) (7). It was prepared similarly to
Pt) ) 4562), 90.5 (dd, P2(Pt), 2+3J (P2-P3) ) 173, J (P2-P1) )
2
29, 1J (P-Pt) ) 2840), 118.3 (d, P3(Fe), 2+3J (P3-P2) ) 173,
2+3J (P-Pt) ) 82). 13C{1H} NMR: δ 5.7 (d, 1C, SiMe), 8.4 (s,
1C, SiMe), 33.8 (s, 6C, C-Me), 51.3 (s, 2C, N-C), 127.4-141.1
(m, 42C, C6H5), 212.9 (d, 2C, CO, 2J (P-C) ) 29), 219.9 (d, 1C,
CO, 2J (P-C) ) 7). 29Si-INEPT NMR: δ 1.95 (d, SiMe2, 4J (P2-
Si) ) 3,3J (Pt-Si) ) 27), 195Pt{1H} NMR: δ -3190 (ddd, 1J (P1-
6, using [(OC)3Fe{µ-Si(OMe)2(OMe)}(µ-dppm)Pd(Me)](Fe-Pd)
(1.0 mmol, 768 mg) and GeNtBuSiMe2NtBu (1.1 mmol, 300 µL).
The complex was isolated in form of nearly colorless thin plates
from a cold Et2O/hexane mixture (0.697 g, 67%). (Anal.
Found: C, 48.92; H, 5.91; N, 2.65. Calc for C42H58N2O6P2-
FePdSi2Ge (M ) 1039.86): C, 48.51; H, 5.62; N, 2.69). IR
(KBr): ν(CO) 1947 s, 1878 s, 1851 s, ν(SiOCH) 2831 w. IR
Pt) ) 4562, J (P2-Pt) ) 2840, 2+3J (P3-Pt) ) 82 Hz).
1
[(O C )3 F e (µ-G e N t B u S i M e 2 N t B u )(µ-d p p m )P t (G e N -
tBu SiMe2NtBu )](Fe-P t) (4). To a solution of 3a (0.5 mmol,
(toluene): ν(CO) 1947 m, 1881 s, 1850 s cm-1
.
1H NMR: δ
0.30 (s, 3H, SiMe), 0.35 (s, 3H, SiMe), 0.40 (d, 3H, PdMe, 3J (P-

Reactions of Fe-Pt and Fe-Pd Complexes
Organometallics, Vol. 15, No. 18, 1996 3875
t
2
H) ) 8.4), 1.24 (s, 18H, Bu), 3.46 (t, 2H, PCH2P, J (P-H) )
10.3), 3.73 (s, 9H, Si(OMe)3), 7.23-7.56 (m, 20H, C6H5). 31P-
{1H} NMR: δ 31.1 (d, P1(Pd-P), 2+3J (P1-P2) ) 118), 72.4 (d,
mode: total number of unique data, 8263; number of observed
unique data, 5298; final R1 (I > 2σ(I)) ) 0.1318; wR2 ) 0.3770.
P2(Fe-P)). 29Si-INEPT NMR: δ 4.07 (d, SiMe2, J (Si-P1) )
4
Ack n ow led gm en t. We are very grateful to the
Deutsche Forschungsgemeinschaft for financial support,
to the CNRS, the Ministe`re de l’Enseignement Su-
pe´rieur et de la Recherche, the Ministe`re des Affaires
Etrange`res (Paris), and the DAAD (PROCOPE project)
for support, and to DEGUSSA AG for a generous gift of
Pd and Pt salts.
3.6), 29.36 (dd, SiOMe, 4J (P1-Si) ) 4.4, 2J (P2-Si) ) 35). 13C-
{1H} NMR: δ 2.5 (d, 1C, SiMe, 5J (P-C) ) 1), 4.7 (s, 1C, SiMe),
6.1 (d, 1C, PdMe, 2J (P-C) ) 3), 33.8 (s, 6C, C-Me), 38.1 (t,
1C, PCH2P), 50.4 (s, 3C, SiOMe), 51.0 (s, 2C, N-C), 127.8 -
2
136.2 (m, 24C, C6H5), 211.1 (d, 2C, CO, J (P-C) ) 25), 214.9
(d, 1C, CO, J (P-C) ) 14 Hz).
2
Cr ysta llogr a p h ic Da ta for Com p lex 7: Crystal system,
triclinic; space group, P1h; a ) 10.704(10), b ) 20.53(2), c )
25.76(3) Å; R ) 68.88(4), â ) 79.33(4), γ ) 80.20(4)°; V ) 5155-
(9) Å3; Z ) 4; d(calc) ) 1.340 g/cm3. Data were collected at
293 K on a Siemens Stoe AED 2 diffractometer using graphite-
monochromated Mo KR radiation (0.710 73 Å). Intensities
were collected from 1.58-22.52° in Θ, using the ω-Θ scan
Su p p or tin g In for m a tion Ava ila ble: Tables of crystal-
lographic data, atom parameters, thermal parameters, and
bond distances and angles (10 pages). Ordering information
is given on any current masthead page.
OM960167U