Unprecedented zwitterionic iminium-chalcogenide bridging ligands in diiron complexes

Article abstract of DOI:10.1021/om060550r

The diiron vinyliminium complexes [Fe₂{μ-η¹: η³-C(R′)=CHC=N(Me)(R)}(μ-CO)(CO)(Cp)₂] [SO₃-CF₃] [R = Xyl, R′ = Me, 1a; R = Xyl, R′ = Tol, 1b; R = Xyl, R′ = CO₂Me, 1e; R = Xyl, R′ = CH ₂OH, 1d; R = Xyl, R′ = Buⁿ, 1e; R′ = Me, R′ = Me, 1f; R = Me, R′ = Toi, 1g; R = Me, R′ = CO ₂Me, 1h; R = Me, R′ = Buⁿ, 1i; R = Me, R′ = CH₂OH, 1l; R = p-C₆H₄-CN, R′ = Tol, 1m; R = p-C₆H₄-OMe, R′ = Me, 1n; Tol = 4-C ₆H₄-Me; Xyl = 2,6-Me₂C₆H ₃] react with elemental sulfur or selenium, in the presence of NaH, to give the zwitterionic vinyliminium compounds [Fe₂{μ- η¹:η³-C(R′)= C(E)C=N(Me)(R)}(μ-CO)(CO) (Cp)₂] [R = Xyl, R′ = Me, E = S, 2a; R = Xyl, R′ = Tol, E = S, 2b; R = Xyl, R′ = CO₂Me, E = S, 2c; R = Xyl, R′ = CH₂OH, E = S, 2d; R = Xyl, R′ = Buⁿ, E = S, 2e; R = Xyl, R′ = Me, E = Se, 3a; R = Xyl, R′ = Tol, E = Se, 3b; R = Me, R′ = Me, E = Se, 3c; R = Me, R′ = Tol, E = Se, 3d; R = Me, R′ = CO₂Me, E = Se, 3e; R = Me, R′ = Buⁿ, E = Se, 3f; R = Me, R′ = CH₂OH, E = Se, 3g]. Similarly, the reaction of la with Me₃NO/NaH results in the formation of [Fe₂{μ-C(Me) C(O)CN(Me)(Xyl)}(M-CO)(CO)(Cp)₂] (4), in which the bridging ligand is better described as a bis-alkylidene. The reactions of 1a,c with S ₈/NaH afford also the five-membered metallacycles [Fe-(Cp)(CO){Cα(NMe(Xyl))Cβ(H)Cλ(R′)S}] [R′ = Me, 6a; R′ = CO₂Me, 6b], as secondary products, in about 15% yield. Conversely, complexes [Fe₂{μ-η¹:η³- C(R′)=CHC=N(Me)(R)}(μ-CO)(CO)(Cp)₂][SO₃-CF ₃], 1f-h,m,n, react with S₈/NaH, giving selectively the five-membered metallacycles [Fe(Cp)(CO)-{C(R′)C(H)C{N(Me)(R)}S}] [R = Me, R′ = Me, 7a; R = Me, R′ = Tol, 7b; R = Me, R′ = CO ₂Me, 7c; R = p-C₆H₄-CN, R′ = Tol, 7d; R = p-C₆H₄-OMe, R′ = Me, 7e]. The molecular structures of 2b·CH₂Cl₂, 3a, 4, 6a, and 7b have been determined by X-ray diffraction studies.

Full text of DOI:10.1021/om060550r

4808
Organometallics 2006, 25, 4808-4816
Unprecedented Zwitterionic Iminium-Chalcogenide Bridging
Ligands in Diiron Complexes
Luigi Busetto, Fabio Marchetti, Stefano Zacchini, and Valerio Zanotti*
Dipartimento di Chimica Fisica e Inorganica, UniVersita` di Bologna, Viale Risorgimento 4, 40136
Bologna, Italy
ReceiVed June 23, 2006
The diiron vinyliminium complexes [Fe2{µ-η1:η3-C(R′)dCHCdN(Me)(R)}(µ-CO)(CO)(Cp)2][SO3-
CF3] [R ) Xyl, R′ ) Me, 1a; R ) Xyl, R′ ) Tol, 1b; R ) Xyl, R′ ) CO2Me, 1c; R ) Xyl, R′ )
CH2OH, 1d; R ) Xyl, R′ ) Bun, 1e; R ) Me, R′ ) Me, 1f; R ) Me, R′ ) Tol, 1g; R ) Me, R′ )
CO2Me, 1h; R ) Me, R′ ) Bun, 1i; R ) Me, R′ ) CH2OH, 1l; R ) p-C6H4-CN, R′ ) Tol, 1m; R )
p-C6H4-OMe, R′ ) Me, 1n; Tol ) 4-C6H4-Me; Xyl ) 2,6-Me2C6H3] react with elemental sulfur or
selenium, in the presence of NaH, to give the zwitterionic vinyliminium compounds [Fe2{µ-η1:η3-C(R′)d
C(E)CdN(Me)(R)}(µ-CO)(CO)(Cp)2] [R ) Xyl, R′ ) Me, E ) S, 2a; R ) Xyl, R′ ) Tol, E ) S, 2b;
R ) Xyl, R′ ) CO2Me, E ) S, 2c; R ) Xyl, R′ ) CH2OH, E ) S, 2d; R ) Xyl, R′ ) Bun, E ) S, 2e;
R ) Xyl, R′ ) Me, E ) Se, 3a; R ) Xyl, R′ ) Tol, E ) Se, 3b; R ) Me, R′ ) Me, E ) Se, 3c; R )
Me, R′ ) Tol, E ) Se, 3d; R ) Me, R′ ) CO2Me, E ) Se, 3e; R ) Me, R′ ) Bun, E ) Se, 3f; R )
Me, R′ ) CH2OH, E ) Se, 3g]. Similarly, the reaction of 1a with Me3NO/NaH results in the formation
of [Fe2{µ-C(Me)C(O)CN(Me)(Xyl)}(µ-CO)(CO)(Cp)2] (4), in which the bridging ligand is better described
as a bis-alkylidene. The reactions of 1a,c with S8/NaH afford also the five-membered metallacycles [Fe-
(Cp)(CO){CR(NMe(Xyl))Câ(H)Cγ(R′)S}] [R′ ) Me, 6a; R′ ) CO2Me, 6b], as secondary products, in
about 15% yield. Conversely, complexes [Fe2{µ-η1:η3-C(R′)dCHCdN(Me)(R)}(µ-CO)(CO)(Cp)2][SO3-
CF3], 1f-h,m,n, react with S8/NaH, giving selectively the five-membered metallacycles [Fe(Cp)(CO)-
{C(R′)C(H)C{N(Me)(R)}S}] [R ) Me, R′ ) Me, 7a; R ) Me, R′ ) Tol, 7b; R ) Me, R′ ) CO2Me,
7c; R ) p-C6H4-CN, R′ ) Tol, 7d; R ) p-C6H4-OMe, R′ ) Me, 7e]. The molecular structures of
2b‚CH2Cl2, 3a, 4, 6a, and 7b have been determined by X-ray diffraction studies.
Chart 1
Introduction
Dinuclear transition metal complexes, providing multisite
interactions between the metal aggregate and coordinated
molecules, offer unique possibilities of substrate activation,
which cannot be expected in mononuclear complexes.1 In
particular, complexes with two adjacent metal atoms are
particularly effective in the activation and transformation of C3-
bridged fragments, including µ-allyls2 and µ-allenyls.3 Our
interest in the area has been focused on the chemistry of bridging
vinyliminium complexes [Fe2{µ-η1:η3-C(R′)dC(R′′)CdN(Me)-
(R)}(µ-CO)(CO)(Cp)2][SO3CF3] (Chart 1)4 and of their diru-
thenium counterparts.5
It has been evidenced that the bridging vinyliminium ligand
is a versatile substrate, accessible to a variety of transformations,
obtained by reaction with nucleophiles, including hydride,6
acetylides,7 and organolithium reagents.8 Further possible
transformations of the bridging C3 unit have been found, owing
(1) (a) Braunstein, P.; Rose`, J. In Metal Cluster in Chemistry; Braunstein,
P., Oro, L. A., Raithby P. R., Eds.; Wiley-VCH: Weinheim, 1999; p 616.
(b) Catalysis by Di- and Polynuclear Metal Cluster Complexes; Adams, R.
A., Cotton, F. A., Eds.; Wiley-VCH: New York, 1998. (c) Adams, R. D.;
Captain, B. J. Organomet. Chem. 2004, 689, 4521. (d) Qin, J. C.; Gavrilova,
A.; Bosnich, B. Pure Appl. Chem. 2001, 73, 221. (e) Van Den Beuken, E.
K.; Feringa, B. L. Tetrahedron 1998, 54, 12985. (f) Severin, K. Chem.
Eur. J. 2002, 8, 1514. (g) Trepanier, S. J.; Dennett, J. N. L.; Sterenberg, B.
T.; McDonald, R.; Cowie, M. J. Am. Chem. Soc. 2004, 126, 8046.
(2) Selected examples include: (a) Dyke, A. F.; Knox, S. A. R.; Naish,
P. J.; Taylor, G. E. J. Chem. Soc., Chem. Commun. 1980, 803. (b) Sumner,
C. E., Jr.; Collier, J. A.; Pettit, R. Organometallics 1982, 1, 1350. (c)
Eisenstadt, A.; Efraty, A. Organometallics 1982, 1, 1100. (d) Adams, P.
Q.; Davies D. L.; Dyke, A. F.; Knox, S. A. R.; Mead, K. A.; Woodward,
P. J. Chem. Soc., Chem. Commun. 1983, 222. (e) Knox, S. A. R.;
Mcpherson, K. A.; Orpen, A. G. J. Organomet. Chem. 1990, 400, 255. (f)
Casey, C. P.; Niccolai, G. P. Organometallics 1994, 13, 2527. (g) Akita,
M.; Hua, R.; Nakanishi, S.; Tanaka, M.; Moro-oka, Y. Organometallics
1997, 16, 5572. (h) Kaneko, J.; Suzuki, T.; Isobe, K.; Maitlis P. M. J.
Organomet. Chem. 1998, 554, 155. (i) Rowsell, B. D.; McDonald, R.;
Ferguson, M. J.; Cowie, M. Organometallics 2003, 22, 2944.
(3) (a) Wojcicki, A. Inorg. Chem. Commun. 2002, 5, 82. (b) Doherty,
S.; Corrigan, J. F.; Carty A. J.; Sappa, E. AdV. Organomet Chem. 1995, 37,
39. (c) Doherty, S.; Hogarth, G.; Waugh, M.; Clegg, W.; Elsegood, M. R.
J. Organometallics 2000, 19, 5696. (d) Doherty, S.; Hogarth, G.; Waugh,
M.; Clegg, W.; Elsegood, M. R. J. Organometallics 2000, 19, 4557. (e)
Doherty, S.; Hogarth, G.; Waugh, M.; Scalan, T. H.; Clegg, W.; Elsegood,
M. R. J. Organometallics 1999, 18, 3178. (f) Doherty, S.; Elsegood, M. R.
J.; Clegg, W.; Rees, N. H.; Scalan, T. H.; Waugh, M. Organometallics
1997, 16, 3221.
(4) (a) Albano, V. G.; Busetto, L.; Marchetti, F.; Monari, M.; Zacchini,
S.; Zanotti, V. Organometallics 2003, 22, 1326. (b) Albano, V. G.; Busetto,
L.; Marchetti, F.; Monari, M.; Zacchini, S.; Zanotti, V. J. Organomet Chem.
2004, 689, 528.
(5) Busetto, L.; Marchetti, F.; Zacchini, S.; Zanotti, V. J. Organomet.
Chem. 2006, 691, 2424.
(6) (a) Albano, V. G.; Busetto, L.; Marchetti, F.; Monari, M.; Zacchini,
S.; Zanotti, V. Organometallics 2004, 23, 3348. (b) Albano, V. G.; Busetto,
L.; Marchetti, F.; Monari, M.; Zacchini, S.; Zanotti, V. J. Organomet. Chem.
2005, 690, 837.
(7) Busetto, L.; Marchetti, F.; Zacchini, S.; Zanotti, V. Eur. J. Inorg.
Chem. 2006, 285.
10.1021/om060550r CCC: $33.50 © 2006 American Chemical Society
Publication on Web 08/22/2006

Unprecedented Iminium-Chalcogenide Bridging Ligands
Organometallics, Vol. 25, No. 20, 2006 4809
Scheme 1
Figure 1. Molecular structure of [Fe2{µ-η1:η3-C(Tol)dC(S)Cd
N(Me)(Xyl)}(µ-CO)(CO)(Cp)2] (2b), with key atoms labeled (all
H atoms have been omitted). Displacement ellipsoids are at the
30% probability level. Only the main image of the disordered Tol
group is reported.
Scheme 2
to the acidic character of the Câ-H in the vinyliminium ligand.9
Proton removal generates reactive intermediates, which rear-
range, resulting in the formation of mono-, di-, or tetranuclear
complexes. The former have been identified as metalla-2-
aminocyclopenta-1,3-dien-5-one and σ-alkynyl µ-aminocarbyne
diiron complexes, respectively, whereas the tetranuclear com-
pounds are generated by dimerization of the parent complexes,
involving C-C bond formation between the Câ positions of two
µ-vinyliminium ligands.9
Figure 2. Molecular structure of [Fe2{µ-η1:η3-C(Me)dC(Se)Cd
N(Me)(Xyl)}(µ-CO)(CO)(Cp)2] (3a), with key atoms labeled (all
H atoms have been omitted). Displacement ellipsoids are at the
30% probability level.
Herein we report on the successful attempt to trap the reactive
deprotonated intermediates by reactions with elemental sulfur
or selenium, or with Me3NO, resulting in the functionalization
of the Câ position with a group 16 heteroatom.
Results and Discussion
The diiron vinyliminium complexes [Fe2{µ-η1:η3-C(R′)d
CHCdN(Me)(R)}(µ-CO)(CO)(Cp)2][SO3CF3] (1a-l) react with
elemental sulfur or selenium, in the presence of NaH in THF
solution, generating the zwitterionic vinyliminium complexes
2a-e and 3a-g, respectively (Scheme 1).
The analogous complex [Fe2{µ-C(Me)C(O)CN(Me)(Xyl)}-
(µ-CO)(CO)(Cp)2] (4) (Scheme 2), containing oxygen instead
of sulfur or selenium, has been obtained, albeit in modest yields
(30%), by reacting 1a with NaH in the presence of Me3NO.
The compounds 2, 3, and 4 have been purified by chroma-
tography and characterized by IR and NMR spectroscopy and
elemental analysis. Moreover, the molecular structures of 2b,
3a, and 4 have been determined by X-ray diffraction studies:
the ORTEP molecular diagrams are shown in Figures 1-3,
whereas relevant bond lengths and angles are reported in Table
Figure 3. Molecular structure of [Fe2{µ-η1:η2-C(Me)C(O)CN(Me)-
(Xyl)}(µ-CO)(CO)(Cp)2], (4), with key atoms labeled (all H atoms
have been omitted). Displacement ellipsoids are at the 30%
probability level.
1, where they are compared to those of the cationic vinyliminium
complex cis-[Fe2{µ-η1:η3-C(Me)dC(Me)CdN(Me)(Xyl)}(µ-
CO)(CO)(Cp)2]+ (5).4b The three complexes 2b, 3a, and 4
display a bridging [µ-C(R′)C(E)CN(Me)(Xyl)] ligand, which
can be better discussed by considering two alternative structures
(Chart 2). In the first (A), the ligand is described as a zwitterionic
vinyliminium, which is µ-η1:η3 coordinated. This type of
(8) Albano, V. G.; Busetto, L.; Marchetti, F.; Monari, M.; Zacchini, S.;
Zanotti, V. J. Organomet. Chem. 2005, 690, 4666.
(9) Busetto, L.; Marchetti, F.; Zacchini, S.; Zanotti, V. Organometallics
2005, 24, 2297.

4810 Organometallics, Vol. 25, No. 20, 2006
Busetto et al.
1945 and 1777 cm-1). Finally, ν(CâO) is found for 4 (in KBr)
at 1465 cm-1, in agreement with its partial double-bond
character.
Table 1. Selected Bond Lengths (Å) and Angles (deg) for 2b,
3a, and 4, Compared to cis-[Fe2{µ-η1:η3-C(Me)dC(Me)Cd
N(Me)(Xyl)}(µ-CO)(CO)(Cp)2]+ (5)
2b
3a
4
5a
The NMR spectra of 2 and 3 indicate the presence in solution
of single species, although several isomers might exist owing
to the mutual positions of the Cp ligands (cis-trans) and to
the orientation of the N substituents, when these are not
equivalent (E-Z isomers). NOE investigations indicate that all
the compounds are cis and that complexes 2 and 3a,b, in which
the N substituents are Me and Xyl, adopt a Z configuration (Xyl
pointing far from Câ), as found in the solid state for 2b, 3a,
and 4. This indicates that the formation of 2, 3, and 4 from 1 is
accompanied by inversion of the configuration at the nitrogen
center, since the parent complexes 1 exist in solution mainly in
the E form.4a It is worth noting that the Z configuration is
preferred when the Câ substituent is more sterically demanding
than H: indeed, Z is the dominant configuration in the
vinyliminium complexes [Fe2{µ-η1:η3-C(R′)dC(R′)CdN(Me)-
(Xyl)}(µ-CO)(CO)(Cp)2]+ (R′ ) alkyl or aryl).4b In a similar
manner, the presence of a heteroatom (O, S, Se) on the Câ
induces the iminium substituents to assume a Z configuration.
The CR resonance, in the 13C NMR spectra of the complexes
containing S or Se, is found at δ ca. 230 ppm, as expected for
a µ-vinyliminium complex. For the same species, the Cγ carbon
resonates in the range δ 179-207 ppm, in accordance with its
alkylidene character. The resonance of Câ is observed at δ ca.
110 ppm in the sulfides 2, whereas it is upfield shifted (i.e., δ
ca. 90 ppm) in the selenides 3. The 13C NMR spectrum of 4 is
significantly different from those of 2 and 3, in agreement with
the prevalence of the bis-alkylidene form (B, Chart 2). In
particular, CR is downfield shifted (δ 258.9 ppm), as expected
for a terminal aminocarbene; also Câ resonates at lower field
(δ 156.9 ppm), because of its carbonyl nature.
The formation of 2-4 presumably proceeds via deprotonation
of Câ-H of the vinyliminium ligand. Although deprotonated
intermediate species have been not identified, it appears
reasonable that proton removal would leave an electron-rich Câ
carbon, susceptible to oxidation by elemental sulfur or selenium
or by Me3NO. It has to be remarked that, in the absence of any
of these reagents, the treatment with NaH produces rearrange-
ments of the vinyliminium complexes, affording binuclear
alkynyl products or mononuclear and tetranuclear derivatives,
previously described.9 Since none of these compounds have been
detected among the reaction products, it is evident that sulfur,
selenium, or Me3NO efficiently traps the reactive intermediates
generated by Câ-H deprotonation.
Hydrogen replacement, in the µ-vinyliminium ligand, by a
group 16 element (O, S, Se), described above, deserves some
further comments. The bridging ligand evidences a dipolar
character, particularly in complexes containing S and Se. The
observed charge separation suggests a description of the ligand
as a betaine. Mesoionic betaines are usually stabilized by a large
delocalization of both positive and negative charge in the cyclic
aromatic structures in which they are embedded.11 Conversely,
in 2 and 3, stabilization to the dipolar organic frame is provided
by metal coordination, according to the bridging modes
described above (Chart 2). It is worth noting that dipolar
iminium thiolates of the type [(RI)(RII)NdCR(R)Câ(S)dCγ(RIII)-
Fe(1)-Fe(2)
Fe(1)-C(11)
Fe(1)-C(12)
Fe(2)-C(12)
Fe(1)-C(13)
Fe(2)-C(13)
Fe(2)-C(14)
Fe(2)-C(15)
C(11)-O(11)
C(12)-O(12)
C(13)-C(14)
C(14)-C(15)
C(15)-N(1)
C(14)-X
2.5489(9) 2.5409(12) 2.5403(8)
2.562(1)
1.750(9)
1.894(8)
1.944(8)
1.955(7)
2.035(7)
2.080(7)
1.839(7)
1.150(9)
1.181(9)
1.39(1)
1.744(5)
1.916(5)
1.918(4)
1.988(4)
2.040(4)
2.151(4)
1.860(4)
1.155(6)
1.182(6)
1.430(6)
1.440(6)
1.307(5)
1.736(4)
1.752(4)
1.911(4)
1.921(4)
1.966(4)
2.034(4)
2.158(3)
1.864(3)
1.150(4)
1.181(4)
1.435(5)
1.431(5)
1.307(4)
1.899(3)
1.747(3)
1.953(3)
1.882(3)
1.979(2)
2.017(2)
2.330(2)
1.874(2)
1.147(3)
1.172(3)
1.446(3)
1.487(3)
1.310(3)
1.254(3)
1.43(1)
1.314(8)
1.52(1)
Fe(1)-C(13)-C(14) 121.3(3)
C(13)-C(14)-C(15) 111.8(3)
C(14)-C(15)-Fe(2) 80.2(3)
C(14)-C(15)-N(1)
a See ref 4b.
120.3(3)
112.6(3)
80.7(2)
129.03(16) 121.8(5)
106.31(18) 115.5(6)
86.97(13)
77.9(4)
129.9(4)
132.4(3)
126.03(19) 131.3(7)
Chart 2
coordination has been discussed in previous publications4 and
shows analogies to the closely related dinuclear propargyl iron
derivatives described by Knox.10 The positive charge is delo-
calized over the whole vinyliminium, whereas the negative
charge is localized on the heteroatom E. Alternatively, the ligand
can be viewed as bridging bis-alkylidene µ-η1:η2 coordinated
(B); in this case, Câ is not bonded to the metal and CâdE has
a double-bonded character. The bonding parameters for both
2b and 3a are very similar to those of the vinyliminium 5, and
therefore, they can be mainly represented by the zwitterionic
form (A). In agreement with this, all three carbon atoms C(13),
C(14), and C(15) (Cγ, Câ, and CR, respectively) are bonded to
Fe(2) [Fe(2)-C(13) 2.040(4) and 2.034(4) Å; Fe(2)-C(14)
2.151(4) and 2.158(3) Å; Fe(2)-C(15) 1.860(4) and 1.864(3)
Å, for 2b and 3a, respectively]. Moreover, both C(13)-C(14)
[1.430(6) and 1.435(5) Å, for 2b and 3a, respectively] and
C(14)-C(15) [1.440(6) and 1.431(5) Å] interactions show some
double-bond character, whereas C(14)-S(1) [1.736(4) Å] and
C(14)-Se(1) [1.899(3) Å] are essentially single bonds. Con-
versely, the structure of 4 is better represented by the bis-
alkylidene form (B), even though some contribution of the
zwitterionic structure (A) has to be considered. In particular,
the Fe(2)-C(14) distance [2.330(2) Å] is considerably elongated
with respect to 2b and 3a, suggesting a very weak interaction
that better agrees with a µ-η1:η2 coordination. Also the C(13)-
C(14) [1.446(3) Å] and C(14)-C(15) [1.487(3) Å] interactions
are slightly longer than in 2b and 3a, indicating a reduced
double-bond character. Conversely, the C(14)-O(1) interaction
[1.254(3) Å] is an almost pure C(sp2)dO double bond, as found
in organic ketones.
(10) (a) Dyke, A. F.; Knox, S. A. R.; Naish, P. J.; Taylor, G. E. J. Chem.
Soc., Chem. Commun. 1980, 409. (b) Dyke, A. F.; Knox, S. A. R.; Naish,
P. J.; Taylor, G. E. J. Chem. Soc., Dalton Trans. 1982 1297.
(11) Sakai, N.; Funabashi, M.; Hamada, T.; Minakata, S.; Ilhyong Ryu,
I.; Komatsu, M. Tetrahedron 1999, 55, 13703, and references therein.
The IR spectra (in dichloromethane solution) of 2 and 3
exhibit two bands due to the terminal and bridging carbonyls
(e.g., for 2a at 1961 and 1790 cm-1, respectively). These ν-
(CO) occur at higher frequencies compared to those of 4 (at

Unprecedented Iminium-Chalcogenide Bridging Ligands
Organometallics, Vol. 25, No. 20, 2006 4811
Scheme 3
(RIV)] are rare,12 and to our knowledge, none have been found
coordinated to metallic centers. A comparison between the
ligand present in 2b and the organic zwitterion PhC[dN+
(CH2CH2)2O]C(S-)dC(Ph)(Ph2PdS) (C)12a shows some analo-
gies but also some interesting differences. In both cases, the
zwitterionic nature of the molecule is evidenced by the fact that
CRdN is essentially a double bond [1.307(5) Å in 2b, 1.310(2)
Å in C], whereas Câ-S is a single bond [1.736(4) Å in 2b,
1.715(2) Å in C], in agreement with charge separation.
Conversely, the CR-Câ [1.440(6) Å in 2b, 1.488(3) Å in C]
and Câ-Cγ [1.430(6) Å in 2b, 1.354(3) Å in C] interactions
indicate an alternating bonding situation in C [CR-Câ single,
CâdCγ double], whereas there is an almost perfect delocalization
in 2b, as a consequence of the coordination to the diiron frame.
Thus, the ligand possesses some allylic character, in agreement
with our previous findings for similar vinyliminium ligands.4
Interestingly, the reactions of 1a,c with S8/NaH do not afford
2a,c as unique reaction products. Chromatography allowed the
Figure 4. Molecular structure of [Fe(Cp)(CO){CR(NMe(Xyl))Câ-
(H)Cγ(Me)S}] (6a), with key atoms labeled (all H atoms, except
H(8), have been omitted). Displacement ellipsoids are at the 30%
probability level.
Table 2. Selected Bond Lengths (Å) and Angles (deg) for
[Fe(Cp)(CO){Cr(NMe(Xyl))Câ(H)Cγ(Me)S}] (6a)
Fe(1)-C(6)
C(6)-O(1)
Fe(1)-S(1)
S(1)-C(9)
N(1)-C(12)
1.736(11)
1.147(11)
2.253(3)
1.711(8)
1.446(10)
C(7)-C(8)
C(8)-C(9)
C(7)-Fe(1)
C(7)-N(1)
N(1)-C(11)
1.440(10)
1.326(11)
1.953(7)
1.328(9)
1.467(10)
isolation of the mononuclear complexes [Fe(Cp)(CO){CR(NMe-
(Xyl))Câ(H)Cγ(R′)S}] [R′ ) Me, 6a; R′ ) CO2Me, 6b], as
minor products (15-20% yield) (Scheme 3).
S(1)-Fe(1)-C(7)
Fe(1)-S(1)-C(9)
S(1)-C(9)-C(8)
C(7)-C(8)-C(9)
S(1)-C(9)-C(10)
C(8)-C(9)-C(10)
86.3(2)
98.7(3)
118.5(6)
120.4(8)
118.3(6)
123.2(7)
C(8)-C(7)-Fe(1)
C(7)-N(1)-C(11)
C(7)-N(1)-C(12)
C(11)-N(1)-C(12)
N(1)-C(7)-C(8)
Fe(1)-C(7)-N(1)
115.8(6)
124.9(7)
122.6(6)
112.5(6)
117.7(7)
126.5(6)
Complexes 6a,b have been characterized by spectroscopy (IR
and NMR) and elemental analysis. Moreover, the molecular
structure of 6a has been ascertained by X-ray diffraction: the
ORTEP molecular diagram is shown in Figure 4, whereas
relevant bond angles and lengths are listed in Table 2.
The molecule can be described as a five-membered 1-metalla-
5-thiacyclopenta-1,3-diene, containing a pseudo-tetrahedrally
coordinated Fe atom. The C(8)-C(9) (Câ-Cγ) interaction
[1.326(11) Å] is very short, suggesting an almost pure double-
bond character. Nonetheless, both C(7)-C(8) [1.440(10) Å] and
C(9)-S(1) [1.711(8) Å] show some shortening compared to
single bonds, indicating some π-delocalization in the ring, which
is, in fact, almost planar [mean deviation from the Fe(1)-S(1)-
C(9)-C(8)-C(7) least-squares plane 0.032 Å]. N(1) adopts a
nearly perfect sp2 hybridization [sum of angles 360.0(11)°], and
the N(1)-C(7) interaction [1.328(9) Å] shows some double-
bond character; relative to the latter, the N(Me)(Xyl) group
adopts the E configuration. Finally, the Fe(1)-C(7) interaction
[1.953(7) Å] is elongated with respect to a pure terminal amino-
carbene bond, showing some vinyl character.13
outlined that complex 6b exists in solution as a mixture of E
and Z isomers, with prevalence of the former. Most relevant
features of the 13C NMR spectra are given by the resonances
related to CR, Câ, and Cγ. The first falls at ca. 250 ppm, at a
value typical for an aminocarbene carbon; the second is found
at ca. 135 ppm, consistent with the olefinic nature of the Câ
carbon; finally, Cγ resonates at lower fields (e.g., for 6a at δ
198.0 ppm), because of the closeness to the sulfur atom.
The formation of 6a,b is peculiar to 1a and 1c, and in the
reactions of 1b,d,e with S8/NaH, the corresponding metallacycle
products have not been observed. Compounds 6a,b resemble
the analogous 1-metalla-2-aminocyclopenta-1,3-dien-5-one com-
plexes [Fe(Cp)(CO){CN(Me)(Xyl)CHC(R′)C(O)}] [R′ ) Me,
CO2Me], obtained by simple treatment of 1a with NaH, which
differ from 6, having a CO group in the place of S within the
metallacycle.9 In both cases, the metallacycles are originated
by the fragmentation of the dinuclear frame, promoted by
reaction with NaH. A further analogy consists in the fact that
the parent vinyliminium ligands remain intact along with their
conversion into the observed metallacycles. Since the Câ-H is
still present in the final products, it is not clear whether proton
removal takes place at some stage of the reaction or NaH acts
mainly as a reducing agent, favoring the fragmentation in the
dinuclear parent compound.
The IR spectra of 6a,b (in CH2Cl2 solution) show a band
due to the carbonyl ligand (e.g., for 6a at 1932 cm-1) and an
absorption attributed to the Câ-Cγ interaction, at ca. 1515 cm-1
.
In the 1H NMR spectra, the Câ-H proton is found at relatively
low fields (e.g., for 6a at δ 5.83 ppm). NOE studies have
(12) (a) Reisser, M.; Maier, A.; Maas, G. Eur. J. Org. Chem. 2003, 2071.
(b) Kantlehner, W.; Hauber, M.; Vettel, M. J. Prakt. Chem. 1996, 338,
403.
(13) (a) Busetto, L.; Marchetti, F.; Zacchini, S.; Zanotti, V.; Zoli, E. J.
Organomet. Chem. 2005, 690, 348. (b) Busetto, L.; Marchetti, F.; Zacchini,
S.; Zanotti, V.; Zoli, E. J. Organomet. Chem. 2005, 690, 1959.

4812 Organometallics, Vol. 25, No. 20, 2006
Busetto et al.
Table 3. Selected Bond Lengths (Å) and Angles (deg) for
Scheme 4
[Fe(Cp)(CO){C(Tol)C(H)C(NMe2)S}] (7b)
Fe(1)-C(6)
C(6)-O(1)
Fe(1)-S(1)
S(1)-C(7)
N(1)-C(17)
1.724(2)
1.155(3)
2.2489(9)
1.706(2)
1.459(4)
C(7)-C(8)
C(8)-C(9)
C(9)-Fe(1)
C(7)-N(1)
N(1)-C(18)
1.426(3)
1.361(3)
1.937(2)
1.338(3)
1.460(4)
S(1)-Fe(1)-C(9)
Fe(1)-S(1)-C(7)
S(1)-C(7)-C(8)
C(7)-C(8)-C(9)
S(1)-C(7)-N(1)
C(8)-C(9)-C(10)
84.68(7)
100.63(8)
115.23(17)
118.7(2)
121.73(18)
116.40(19)
C(8)-C(9)-Fe(1)
C(7)-N(1)-C(17)
C(7)-N(1)-C(18)
C(17)-N(1)-C(18)
N(1)-C(7)-C(8)
Fe(1)-C(9)-C(10)
120.73(16)
122.3(2)
121.1(2)
116.5(2)
123.0(2)
122.87(15)
Chart 3. Resonance Forms for 7b
Scheme 5
this plane [dihedral angles C(8)-C(7)-N(1)-C(17) -1.3(4)°
and C(8)-C(7)-N(1)-C(18) -179.0(3)°]. The observed co-
planarity as well as the perfect sp2 hybridization of N(1) [sum
of angles 359.9(3)°] indicates some π-interaction between the
five-membered ring and NMe2 [C(7)-N(1) 1.338(3) Å]. All
these data indicate that the five-membered ring is essentially
aromatic.
Figure 5. Molecular structure of [Fe(Cp)(CO){C(Tol)C(H)C-
(NMe2)S}] (7b), with key atoms labeled (all H atoms, except H(8),
have been omitted). Displacement ellipsoids are at the 30%
probability level. Only the main image of the disordered Cp ligand
is reported.
Completely different pathways are observed by reacting the
It is not obvious why, for 7a-c, sulfur addition occurs at the
CR instead of at the Câ carbon, as in the complexes of types 2
and 3. A possible explanation is related to the presence of less
sterically demanding iminium substituents, in place of Xyl. The
latter has been demonstrated to act as a “protecting group” and
inhibits addition at the iminium carbon (CR) for steric reasons.
To evidence possible electronic effects, in addition to steric
effects, the investigation has been extended to the complexes
1m and 1n (Scheme 5), displaying the para-methoxy and para-
cyano phenyl substituent, respectively. Since 1m and 1n are
novel compounds, details on their syntheses, from the corre-
sponding isocyanide diiron precursors, are given in the Experi-
mental Section.
complexes 1f-h with elemental sulfur, in the presence of
sodium hydride. In fact, the mononuclear species [Fe(Cp)(CO)C-
(R′)C(H)C{N(Me)(R)}S] (R ) Me, R′ ) Me, 7a; R ) Me, R′
) Tol, 7b; R ) Me, R′ ) CO2Me, 7c) are formed (Scheme 4).
Compounds 7a-c have been characterized on the basis of
spectroscopic data, and the molecular structure of 7b has been
determined by X-ray crystallography (Figure 5 and Table 3).
The iron atom is pseudo-tetrahedrally coordinated to a Cp, a
CO, and a chelating vinyl thiopropargylamide ligand, and the
resulting five-membered ring can be described as a 1-metalla-
5-thiacyclopenta-2,4-diene. In agreement with this, both C(7)-
S(1) [1.706(2) Å] and C(8)-C(9) [1.361(3) Å] interactions show
a considerable double-bond character. The Fe(1)-C(9) interac-
tion [1.937(2) Å] is shorter than a pure vinyl σ-Fe-C(sp2) bond
and suggests some π-back-donation from the metal. Taking this
into consideration, the molecule can be alternatively described
as a 1-metalla-5-thiacyclopenta-1,3-diene (Chart 3); in agree-
ment with this, also the C(7)-C(8) interaction [1.426(3) Å]
displays some double-bond character. The ring is perfectly
planar [mean deviation from the Fe(1)-S(1)-C(7)-C(8)-C(9)
least-squares plane 0.0084 Å] and also the NMe2 group lies in
Again, both 1m and 1n react with NaH/S8, generating the
corresponding metallacycles (Scheme 5). Therefore, steric
effects are dominant, and only the Xyl substituent prevents the
reaction from taking place at the iminium carbon. However, it
has to be remarked that the reactions of 1f-l with selenium
occur exclusively at the Câ carbon (Scheme 1, compounds 3c-
g), despite the presence of methyls as substituents at the iminium
nitrogen. This observation indicates that the nature of the
heteroatom also affects the reaction outcome.

Unprecedented Iminium-Chalcogenide Bridging Ligands
Organometallics, Vol. 25, No. 20, 2006 4813
and used as received. [Fe2(CO)4(Cp)2] was purchased from Strem
Finally, the reactions outlined in Schemes 3, 4, and 5 represent
interesting and versatile syntheses of five-membered thiamet-
allacycles containing iron; to the best of our knowledge, only a
few of these molecules have been structurally characterized.14
and used as received. 1a-l were prepared by published methods.4
Synthesis of [Fe2{µ-CN(Me)(R)}(µ-CO)(CO)2(Cp)2][SO3CF3]
(R ) 4-C6H4CN, R ) 4-C6H4OMe). The isocyanide CN(4-C6H4-
CN) (154 mg, 1.20 mmol) and [Fe2(CO)2(µ-CO)2(Cp)2] (650 mg,
1.84 mmol) were dissolved in MeCN (35 mL). The solution was
stirred at boiling temperature for 8 h. Then, the solvent was removed
and the residue was dissolved in CH2Cl2 (25 mL) and treated with
CF3SO3CH3 (1.30 mmol). The resulting solution was stirred at room
temperature for 4 h. Chromatography on an alumina column, with
MeOH as eluent, afforded [Fe2{µ-CN(Me)(4-C6H4CN)}(µ-CO)-
(CO)2(Cp)2][SO3CF3]. Yield: 371 mg, 50%. Anal. Calcd for
C23H17F3Fe2N2O6S: C, 44.69; H, 2.77; N, 4.53. Found: C, 44.71;
H, 2.82; N, 4.55. IR (CH2Cl2): ν(CtN) 2122 (m), ν(CO) 2023
Conclusions
The reactions of diiron vinyliminium complexes, containing
an acidic Câ-H hydrogen, with NaH in the presence of
elemental S or Se or with Me3NO, respectively, provide a
general entry to the hydrogen replacement with the correspond-
ing group 16 element, affording complexes of the type [Fe2-
{µ-C(R′)C(E)CN(Me)(R)}(µ-CO)(CO)(Cp)2]. The bridging ligand
in the latter can be described either as a zwitterionic µ-η1:η3
vinyliminium or as a µ-η1:η2 bis-alkylidene (Chart 3, structures
A and B, respectively). The zwitterionic form better describes
the vinyliminium ligand containing S or Se, whereas the bis-
alkylidene form prevails when the oxygen atom is present.
(vs), 1992 (s), 1840 (s), ν(µ-CN) 1552 (m) cm-1 1H NMR
.
(CDCl3): δ 7.97-7.71 (m, 4 H, C6H4); 5.49, 4.80 (s, 10 H, Cp);
4.59 (s, 3 H, NMe). 13C{1H} NMR (CDCl3): δ 326.8 (µ-C); 252.7
(µ-CO); 208.5, 207.2 (CO); 152.8, 134.6, 126.7 (C6H4); 120.9
(C6H4CN); 90.5, 90.1 (Cp); 57.2 (NMe).
On the other hand, the study has evidenced that the iminium
carbon (CR) and the Cγ of the vinyliminium ligand are also
susceptible to reacting with sulfur, leading to the fragmentation
of the dinuclear complexes and the formation of five-membered
metallacycles, which include the vinyliminium ligand and a S
atom.
Whereas Cγ-S bond formation appears rather limited and
unpredictable, the addition of sulfur to the iminium carbon (CR)
occurs selectively, when the CR position is not sterically
protected by the presence of the Xyl substituent.
Complex [Fe2{µ-CN(Me)(4-C6H4OMe)}(µ-CO)(CO)2(Cp)2][SO3-
CF3] was prepared by the same procedure described for [Fe2{µ-
CN(Me)(4-C6H4CN)}(µ-CO)(CO)2(Cp)2][SO3CF3], by using CN(4-
C6H4OMe) and [Fe2(CO)2(µ-CO)2(Cp)2]. Yield: 86%. Anal. Calcd
for C23H20F3Fe2NO7S: C, 44.33; H, 3.23; N, 2.25. Found: C, 44.25;
H, 3.18; N, 2.19. IR (CH2Cl2): ν(CO) 2022 (vs), 1991 (s), 1837
(s), ν(µ-CN) 1537 (m) cm-1. 1H NMR (CDCl3): δ 7.90-7.08 (m,
4 H, C6H4); 5.50, 4.83 (s, 10 H, Cp); 4.58 (s, 3 H, NMe); 3.90 (s,
3 H, OMe). 13C{1H} NMR (CDCl3): δ 324.3 (µ-C); 254.5 (µ-
CO); 208.6, 207.6 (CO); 159.6, 143.8, 126.4, 115.1 (C6H4); 90.3,
90.0 (Cp); 57.4 (NMe); 55.6 (OMe).
Finally, the results herein presented reinforce our findings
on the very rich chemistry of bridging diiron vinyliminium
complexes. In particular, the preparation of the new zwitterionic
iminium thiolate (selenolate) ligands promises further develop-
ments in the synthesis of new highly functionalized organic
frames, bridging Fe atoms.
Synthesis of [Fe2{µ-CN(Me)(R)}(µ-CO)(CO)(NCMe)(Cp)2]-
[SO3CF3] [R ) 4-C6H4CN, 4-C6H4OMe]. Complex [Fe2{µ-CN-
(Me)(4-C6H4CN)}(µ-CO)(CO)2(Cp)2][SO3CF3] (200 mg, 0.324
mmol) was dissolved in MeCN (15 mL) and treated with Me3NO
(32 mg, 0.427 mmol). The resulting solution was stirred for 20
min and filtered on a Celite pad. Solvent removal, under reduced
pressure, gave a brown residue of [Fe2{µ-CN(Me)(4-C6H4CN)}-
(µ-CO)(CO)(NCMe)(Cp)2][SO3CF3]. Yield: 153 mg, 75%. Anal.
Calcd for C24H20F3Fe2N3O5S: C, 45.67; H, 3.19; N, 6.66. Found:
C, 45.75; H, 3.12; N, 6.68. IR (CH2Cl2): ν(CtN) 2118 (m), ν-
Experimental Section
General Procedures. All reactions were routinely carried out
under a nitrogen atmosphere, using standard Schlenk techniques.
Solvents were distilled immediately before use under nitrogen from
appropriate drying agents. Chromatography separations were carried
out on columns of deactivated alumina (4% w/w water). Glassware
was oven-dried before use. Infrared spectra were recorded at 298
K on a Perkin-Elmer Spectrum 2000 FT-IR spectrophotometer, and
elemental analyses were performed on a ThermoQuest Flash 1112
Series EA instrument. ESI-MS spectra were recorded on Waters
Micromass ZQ 4000 with samples dissolved in CH3CN. All NMR
measurements were performed at 298 K on a Mercury Plus 400
instrument. NMR signals due to a second isomeric form (where it
has been possible to detect and/or resolve them) are italicized. The
1
(CO) 1984 (vs), 1820 (s) cm-1. H NMR (CDCl3): δ 7.98-7.28
(m, 4 H, C6H4); 5.11, 4.97, 4.43 (s, 10 H, Cp); 4.60 (s, 3 H, NMe);
1.98 (s, 3 H, NCMe). Isomer ratio (E/Z) 3:1. 13C{1H} NMR
(CDCl3): δ 338.4 (µ-C); 264.3 (µ-CO); 211.3 (CO); 145.4-127.2
(C6H4 and NCMe); 117.8 (C6H4CN); 89.0, 88.5, 87.4, 86.9 (Cp);
56.3, 53.7 (NMe); 4.92, 4.18 (NCMe).
Complex [Fe2{µ-CN(Me)(4-C6H4OMe)}(µ-CO)(CO)(NCMe)-
(Cp)2][SO3CF3] was prepared by the same procedure described for
[Fe2{µ-CN(Me)(4-C6H4CN)}(µ-CO)(CO)(NCMe)(Cp)2]
[SO3CF3], by reacting [Fe2{µ-CN(Me)(4-C6H4OMe)}(µ-CO)(CO)2-
(Cp)2][SO3CF3] with Me3NO in MeCN. Yield: 80%. Anal. Calcd
for C24H23F3Fe2N2O6S: C, 45.31; H, 3.64; N, 4.40. Found: C,
45.22; H, 3.61; N, 4.17. IR (CH2Cl2): ν(CO) 1985 (vs), 1817 (s),
1
chemical shifts for H and 13C were referenced to internal TMS.
1
The spectra were fully assigned via H,13C correlation measured
1
ν(µ-CN) 1527 (m) cm-1. H NMR (CDCl3): δ 7.65-7.06 (m, 4
using gs-HSQC and gs-HMBC experiments.15 NOE measurements
were recorded using the DPFGSE-NOE sequence.16 All the reagents
were commercial products (Aldrich) of the highest purity available
H, C6H4); 5.08, 4.94, 4.45, 4.29 (s, 10 H, Cp); 4.87, 4.57 (s, 3 H,
NMe); 3.90, 3.89 (s, 3 H, OMe); 2.01, 1.99 (s, 3 H, NCMe). Isomer
ratio (E/Z) 1:1. 13C{1H} NMR (CDCl3): δ 336.4, 336.3 (µ-C);
265.9, 265.8 (µ-CO); 211.7, 210.9 (CO); 159.3, 159.1, 144.1, 143.6,
126.4, 115.0, 114.9 (C6H4); 130.2, 129.7 (NCMe); 88.6, 88.3, 87.0,
86.7 (Cp); 56.5, 55.7 (NMe); 55.6, 55.5 (OMe); 3.91 (NCMe).
Synthesis of [Fe2{µ-η1:η3-Cγ(R′)dCâ(H)CRdN(Me)(R)}(µ-
CO)(CO)(Cp)2][SO3CF3] [R ) 4-C6H4-CN, R′ ) Tol, 1m; R )
4-C6H4-OMe, R′ ) Me, 1n; Tol ) 4-C6H4-Me]. Complex [Fe2-
{µ-CN(Me)(4-C6H4-CN)}(µ-CO)(CO)(NCMe)(Cp)2][SO3CF3] (150
mg, 0.238 mmol) was dissolved in CH2Cl2 (20 mL) and treated
with HCtCTol (0.40 mmol). The solution was stirred at reflux
temperature for 4 h. Chromatography on an alumina column, with
(14) (a) Choi, N.; Kabe, Y.; Ando, W. Organometallics 1992, 11, 1506.
(b) Kergoat, R.; Kubicki, M. M.; Gomes de Lima, L. C.; Scordia, H.;
Guerchais, J. E.; L’Haridon, P. J. Organomet. Chem. 1989, 367, 143. (c)
Guerchais, J. E.; Le Floch-Perennou, F.; Petillon, F. Y.; Keith, A. N.;
Munojlovic-Muir, L.; Muir, K. W.; Sharp, D. W. A. Chem. Commun. 1979,
410. (d) Ashby, M. T.; Enemark, J. H. Organometallics 1987, 6, 1318. (e)
Marsh, R. E. Acta Crystallogr., Sect. B 1999, 55, 93.
(15) Wilker, W.; Leibfritz, D.; Kerssebaum, R.; Beimel, W. Magn. Reson.
Chem. 1993, 31, 287.
(16) Stott, K.; Stonehouse, J.; Keeler, J.; Hwang, T. L.; Shaka, A. J. J.
Am. Chem. Soc. 1995, 117, 4199.

4814 Organometallics, Vol. 25, No. 20, 2006
Busetto et al.
1
MeOH as eluent, afforded 1m. Yield: 134 mg, 80%. Anal. Calcd
for C31H25F3Fe2N2O5S: C, 52.72; H, 3.57; N, 3.97. Found: C,
52.66; H, 3.66; N, 4.01. IR (CH2Cl2): ν(CtN) 2119 (s), ν(CO)
1599 (w) cm-1. IR (KBr pellets): ν(CS) 687 (w) cm-1. H NMR
(CDCl3): δ 7.39-7.22 (m, 3 H, Me2C6H3); 4.91, 4.54 (s, 10 H,
Cp); 4.19 (s, 3 H, CO2Me); 3.64 (s, 3 H, NMe); 2.60, 2.08 (s, 6 H,
Me2C6H3). 13C{1H} NMR (CDCl3): δ 261.7 (µ-CO); 236.5 (CR);
211.6 (CO); 180.3, 179.0 (CO2Me and Cγ); 142.4 (ipso-Me2C6H3);
135.3, 134.3, 129.2, 129.1, 128.6 (Me2C6H3); 115.4 (Câ); 90.6, 89.1
(Cp); 52.2 (CO2Me); 46.0 (NMe); 18.2, 17.8 (Me2C6H3).
1
1994 (vs), 1814 (s), ν(CRN) 1601 (s) cm-1. H NMR (CDCl3): δ
7.95-7.11 (m, 8 H, C6H4CN and C6H4Me); 5.32, 5.30, 5.09, 4.90
(s, 10 H, Cp); 4.50 (s, 1 H, CâH); 4.39, 3.69 (s, 3 H, NMe); 2.45,
2.42 (s, 3 H, C6H4Me). E/Z ratio 4:1. 13C{1H} NMR (CDCl3): δ
253.5 (µ-CO); 232.6 (CR); 209.4 (CO); 206.3 (Cγ); 153.1 (ipso-
C6H4Me); 148.0 (ipso-C6H4CN); 137.6-122.2 (C6H4CN and C6H4-
Me); 117.4 (C6H4CN); 91.9, 91.7, 88.0, 88.4 (Cp); 55.1 (Câ); 55.4,
45.9 (NMe); 21.1 (C6H4Me).
Compound 1n was prepared by reacting [Fe2{µ-CN(Me)(p-C6H4-
OMe)}(µ-CO)(CO)(NCMe)(Cp)2][SO3CF3] (150 mg, 0.236 mmol)
with a large excess of HCtCMe, at room temperature for 12 h.
2d (yield: 80%; color: green). Anal. Calcd for C25H25Fe2-
NO3S: C, 56.52; H, 4.74; N, 2.64. Found: C, 56.51; H, 4.83; N,
2.50. IR (CH2Cl2): ν(CO) 1967 (vs), 1789 (s), ν(CRN) 1599 (w)
cm-1. H NMR (CDCl3): δ 7.39-7.24 (m, 3 H, Me2C6H3); 6.85
1
3
2
(dd, JHH ) 4.76 Hz, 1 H, OH); 6.02, 5.95 (dd, JHH ) 12.99 Hz,
3JHH ) 4.76 Hz, 2 H, CH2OH); 4.99, 4.52 (s, 10 H, Cp); 3.57 (s,
3 H, NMe); 2.57, 2.10 (s, 6 H, Me2C6H3). 13C{1H} NMR (CDCl3):
δ 262.6 (µ-CO); 236.5 (CR); 212.1 (CO); 201.2 (Cγ); 141.2 (ipso-
Me2C6H3); 135.5-128.7 (Me2C6H3); 88.9, 88.8 (Cp); 73.0 (CH2);
45.7 (NMe); 18.1, 17.7 (Me2C6H3).
1n (yield: 79%). Anal. Calcd for C25H24F3Fe2NO6S: C, 47.27;
H, 3.81; N, 2.21. Found: C, 47.39; H, 3.97; N, 2.15. IR (CH2Cl2):
ν(CO) 1991 (vs), 1812 (s), ν(CRN) 1640 (w) cm-1 1H NMR
.
2e (yield: 77%; color: green). Anal. Calcd for C28H31Fe2-
NO2S: C, 60.34; H, 5.61; N, 2.51. Found: C, 60.26; H, 5.54; N,
2.48. IR (CH2Cl2): ν(CO) 1961 (vs), 1789 (s), ν(CRN) 1604 (w)
(CDCl3): δ 7.52-6.77 (m, 4 H, C6H4OMe); 5.31, 5.25, 5.11, 4.77
(s, 10 H, Cp); 4.97, 4.53 (s, 1 H, CâH); 4.24, 3.57 (s, 3 H, NMe);
3.91, 3.75 (s, 3 H, OMe); 3.89, 3.81 (s, 3 H, CγMe). E/Z ratio 2:1.
13C{1H} NMR (CDCl3): δ 255.9 (µ-CO); 230.0, 229.1 (CR); 209.9,
209.5 (CO); 208.4 (Cγ); 159.8, 159.5 (ipso-C6H4OMe); 153.1 (ipso-
C6H4Me); 139.1, 136.2, 126.0, 122.6, 114.5, 114.3 (C6H4OMe);
90.4, 90.3, 88.0, 87.8 (Cp); 55.4 (OMe); 54.0, 53.8 (Câ); 53.7, 46.5
(NMe); 42.4, 42.2 (CγMe).
1
cm-1. H NMR (CDCl3): δ 7.37-7.20 (m, 3 H, Me2C6H3); 4.97,
4.32 (s, 10 H, Cp); 3.77, 2.77 (m, 2 H, CγCH2); 1.85, 1.72 (m, 4
H, CγCH2CH2CH2); 3.57 (s, 3 H, NMe); 2.62, 2.09 (s, 6 H,
Me2C6H3); 1.18 (m, 3 H, CγCH2CH2CH2CH3). 13C{1H} NMR
(CDCl3): δ 264.5 (µ-CO); 233.7 (CR); 212.3 (CO); 206.7 (Cγ);
142.1 (ipso-Me2C6H3); 135.6, 134.7, 128.9, 128.5 (Me2C6H3); 109.9
(Câ); 89.8, 89.0 (Cp); 51.7, 33.6, 23.9 (CH2); 45.6 (NMe); 18.3,
17.9 (Me2C6H3); 14.4 (CγCH2CH2CH2CH3).
Synthesis of [Fe2{µ-η1:η3-C(R′)dC(E)CdN(Me)(R)}(µ-CO)-
(CO)(Cp)2] (R ) Xyl, R′ ) Me, E ) S, 2a; R ) Xyl, R′ ) Tol,
E ) S, 2b; R ) Xyl, R′ ) CO2Me, E ) S, 2c; R ) Xyl, R′ )
CH2OH, E ) S, 2d; R ) Xyl, R′ ) Bun, E ) S, 2e; R ) Xyl, R′
) Me, E ) Se, 3a; R ) Xyl, R′ ) Tol, E ) Se, 3b; R ) Me, R′
) Me, E ) Se, 3c; R ) Me, R′ ) Tol, E ) Se, 3d; R ) Me, R′
) CO2Me, E ) Se, 3e; R ) Me, R′ ) Bun, E ) Se, 3f; R ) Me,
R′ ) CH2OH, E ) Se, 3g). A mixture of 1a (202 mg, 0.319 mmol)
and S8 (300 mg, 1.17 mmol) in THF (20 mL) was treated with
NaH (38 mg, 1.60 mmol). The mixture was stirred for 30 min,
then it was filtered on an alumina pad. Solvent removal gave a
residue that was dissolved in CH2Cl2 and chromatographed on
alumina: the band corresponding to 2a was collected using THF
as eluent. The product was obtained as a green powder upon solvent
removal. Yield: 118 mg, 72%. Anal. Calcd for C25H25Fe2NO2S:
C, 58.28; H, 4.89; N, 2.72. Found: C, 58.24; H, 4.96; N, 2.71. IR
(CH2Cl2): ν(CO) 1961 (vs), 1790 (s), ν(CRN) 1602 (w) cm-1. IR
3a (yield: 85%, color: green). Anal. Calcd for C25H25Fe2NO2-
Se: C, 53.42; H, 4.48; N, 2.49. Found: C, 53.36; H, 4.47; N, 2.52.
IR (CH2Cl2): ν(CO) 1965 (vs), 1793 (s), ν(CRN) 1604 (w) cm-1
.
1H NMR (CDCl3): δ 7.36-7.21 (m, 3 H, Me2C6H3); 4.99, 4.30 (s,
10 H, Cp); 4.13 (s, 3 H, CγMe); 3.57 (s, 3 H, NMe); 2.67, 2.10 (s,
6 H, Me2C6H3). 13C{1H} NMR (CDCl3): δ 262.7 (µ-CO); 228.9
(CR); 211.8 (CO); 202.1 (Cγ); 141.7 (ipso-Me2C6H3); 135.9, 134.6,
128.9, 128.6 (Me2C6H3); 90.7 (Câ); 90.5, 89.4 (Cp); 46.6 (NMe);
41.5 (CγMe); 18.3, 18.1 (Me2C6H3).
3b (yield: 85%, color: red). Anal. Calcd for C31H29Fe2NO2Se:
C, 58.34; H, 4.58; N, 2.19. Found: C, 58.36; H, 4.47; N, 2.31. IR
1
(CH2Cl2): ν(CO) 1967 (vs), 1793 (s), ν(CRN) 1605 (w) cm-1. H
NMR (CDCl3): δ 7.54-7.21 (m, 7 H, Me2C6H3 and C6H4Me);
4.59, 4.54 (s, 10 H, Cp); 3.65 (s, 3 H, NMe); 2.69, 2.12 (s, 6 H,
Me2C6H3); 2.43 (s, 3 H, C6H4Me). 13C{1H} NMR (CDCl3): δ 262.6
(µ-CO); 229.5 (CR); 212.3 (CO); 199.2 (Cγ); 154.7 (ipso-C6H4Me);
141.7 (ipso-Me2C6H3); 135.9, 134.8, 134.4, 129.1, 129.0, 128.8,
128.7, 125.7 (Me2C6H3 and C6H4Me); 90.6, 90.2 (Cp); 89.6 (Câ);
46.9 (NMe); 21.3 (C6H4Me); 18.5, 18.1 (Me2C6H3).
1
(KBr pellets): ν(CS) 689 (w) cm-1. H NMR (CDCl3): δ 7.38-
7.21 (m, 3 H, Me2C6H3); 4.97, 4.29 (s, 10 H, Cp); 4.03 (s, 3 H,
CγMe); 3.59 (s, 3 H, NMe); 2.61, 2.11 (s, 6 H, Me2C6H3). 13C{1H}
NMR (CDCl3): δ 264.0 (µ-CO); 234.6 (CR); 212.0 (CO); 199.6
(Cγ); 142.2 (ipso-Me2C6H3); 135.5, 134.5, 128.9, 128.8, 128.4
(Me2C6H3); 113.1 (Câ); 89.7, 89.3 (Cp); 45.7 (NMe); 38.9 (CγMe);
18.4, 17.9 (Me2C6H3).
Compounds 2b-e and 3a-g were prepared by the same
procedure described for 2a, by reacting S (or Se) and NaH with
1b-l, respectively. Crystals of 2b and 3a suitable for X-ray analysis
were obtained by CH2Cl2 solutions layered with petroleum ether
(bp 40-60 °C), at -20 °C.
3c (yield: 82%, color: green). Anal. Calcd for C18H19Fe2NO2-
Se: C, 45.80; H, 4.06; N, 2.97. Found: C, 45.77; H, 4.12; N, 3.03.
IR (CH2Cl2): ν(CO) 1968 (vs), 1783 (s), ν(CRN) 1657 (m) cm-1
.
1H NMR (CDCl3): δ 4.99, 4.56 (s, 10 H, Cp); 4.02 (s, 3 H, Cγ-
Me); 3.76, 3.33 (s, 6 H, NMe). 13C{1H} NMR (CDCl3): δ 265.9
(µ-CO); 226.1 (CR); 211.0 (CO); 199.7 (Cγ); 91.2 (Câ); 90.4, 89.0
(Cp); 45.1, 44.6 (NMe); 41.1 (CγMe).
2b (yield 80%; color: green). Anal. Calcd for C31H29Fe2NO2S:
3d (yield: 88%, color: green). Anal. Calcd for C24H23Fe2NO2-
C. 62.97; H. 4.94, N 2.37. Found: C. 63.01; H. 4.90, N 2.29. IR
Se: C, 52.59; H, 4.23; N, 2.56. Found: C, 52.62; H, 4.18; N, 2.62.
1
(CH2Cl2): ν(CO) 1963 (vs), 1790 (s), ν(CN) 1599 (m) cm-1. H
IR (CH2Cl2): ν(CO) 1970 (vs), 1783 (s), ν(CRN) 1657 (m) cm-1
.
1H NMR (CDCl3): δ 7.52, 7.38 (d, 4 H, 3JHH ) 6.0 Hz, MeC6H4);
4.81, 4.60 (s, 10 H, Cp); 3.81, 3.38 (s, 6 H, NMe); 2.41 (s, 3 H,
MeC6H4). 13C{1H} NMR (CDCl3): δ 265.8 (µ-CO); 227.0 (CR);
211.3 (CO); 196.9 (Cγ); 154.5 (ipso-MeC6H4); 134.4, 129.2, 128.6,
128.5, 125.2 (MeC6H4); 90.8 (Câ); 90.2, 90.0 (Cp); 45.0, 44.8
(NMe); 21.2 (MeC6H4).
NMR (CDCl3): δ 7.59-7.24 (7 H, MeC6H4 and Me2C6H3); 4.59,
4.55 (s, 10 H, Cp); 3.69 (s, 3 H, NMe); 2.65, 2.16 (s, 3 H, Me2C6H3);
2.45 ppm (s, 3 H, MeC6H4). 13C{1H} NMR (CDCl3): δ 264.3 (µ-
CO); 235.3 (CR); 212.7 (CO); 196.1 (Cγ); 153.9 (ipso-MeC6H4);
142.2 (ipso-Me2C6H3); 135.6-126.2 (MeC6H4 and Me2C6H3); 112.8
(Câ); 90.5 89.3 (Cp); 45.6 (NMe); 21.3 (MeC6H4); 18.5 17.9 ppm
(Me2C6H3).
2c (yield: 75%; color: green). Anal. Calcd for C26H25Fe2-
NO4S: C, 55.84; H, 4.51; N, 2.50. Found: C, 55.91; H, 4.37; N,
2.52. IR (CH2Cl2): ν(CO) 1972 (vs), 1799 (s), 1701 (m), ν(CRN)
3e (yield: 82%, color: brown). Anal. Calcd for C19H19Fe2NO4-
Se: C, 44.23; H, 3.71; N, 2.71. Found: C, 44.30; H, 3.67; N, 2.65.
IR (CH2Cl2): ν(CO) 1978 (vs), 1793 (s), 1701 (m), ν(CRN) 1654
1
(m) cm-1. H NMR (CDCl3): δ 4.90, 4.78 (s, 10 H, Cp); 4.14 (s,

Unprecedented Iminium-Chalcogenide Bridging Ligands
Organometallics, Vol. 25, No. 20, 2006 4815
Table 4. Crystal Data and Experimental Details for 2b‚CH2Cl2, 3a, 4, 6a, and 7b
2b‚CH2Cl2
3a
4
6a
7b
formula
fw
C32H31Cl2Fe2NO2S
676.24
C25H25Fe2NO2Se
562.12
C25H25Fe2NO3
499.16
C19H21FeNOS
367.28
C18H19FeNOS
353.25
T, K
293(2)
100(2)
296(2)
295(2)
293(2)
λ, Å
0.71073
monoclinic
P21/n
8.4612(17)
16.310(3)
22.242(4)
90
98.27(3)
90
3037.6(11)
4
1.479
1.230
1392
0.71073
triclinic
P1h
0.71073
monoclinic
P21/c
10.498(2)
13.149(3)
16.805(3)
90
101.91(3)
90
2269.8(8)
4
0.71073
orthorhombic
Pbca
12.947(3)
16.041(4)
17.013(5)
90
0.71073
triclinic
P1h
cryst syst
space group
a, Å
b, Å
8.3952(17)
8.8375(18)
17.233(3)
76.57(3)
82.09(3)
61.98(3)
1097.2(4)
2
9.5043(19)
10.032(2)
10.085(2)
113.79(3)
102.08(3)
95.94(3)
841.2(3)
2
c, Å
R, deg
â, deg
90
90
γ, deg
cell volume, Å3
Z
3533.3(16)
8
1.381
0.975
1536
Dc, g cm-3
1.701
3.003
568
1.461
1.304
1032
1.395
1.021
368
µ, mm-1
F(000)
cryst size, mm
θ limits, deg
no. of reflns collected
no. of indep reflns
no. of data/restraints/
params
0.22 × 0.18 × 0.13
1.55-25.03
26 500
5358 [Rint ) 0.0831]
5358/271/458
0.26 × 0.22 × 0.15
1.22-30.51
13 026
6670 [Rint ) 0.0685]
6670/146/284
0.23 × 0.18 × 0.14
1.98-30.51
300 582
6919 [Rint ) 0.0669]
6919/0/284
0.18 × 0.14 × 0.11
2.35-25.00
23 768
3119 [Rint ) 0.1638]
3119/1/215
0.31 × 0.25 × 0.18
2.24-27.88
9469
4009 [Rint ) 0.0256]
4009/46/201
goodness on fit on F2
R1 (I > 2σ(I))
wR2 (all data)
largest diff peak and
hole, e Å-3
0.977
0.0498
0.1409
0.563/-0.476
0.987
0.0536
0.1448
1.671/-1.173
1.001
0.0435
0.1188
0.582/ -0.484
1.325
0.1156
0.2183
0.718/ -0.505
1.040
0.0425
0.1201
0.563/-0.506
3 H, CO2Me); 3.71, 3.37 (s, 6 H, NMe). 13C{1H} NMR (CDCl3):
δ 262.9 (µ-CO); 227.6 (CR); 210.3 (CO); 181.1 (Cγ); 178.4 (CO2-
Me); 92.8 (Câ); 91.6, 88.8 (Cp); 52.2 (CO2Me); 45.4, 44.8 (NMe).
3f (yield: 83%, color: brown). Anal. Calcd for C21H25Fe2NO2-
Se: C, 49.06; H, 4.90; N, 2.72. Found: C, 49.12; H, 4.85; N, 2.78.
secondary product in the reaction of 1a with S8/NaH described
above and isolated by chromatography as an orange band by using
CH2Cl2 as eluent. Yield: 18 mg, 15%. Crystals suitable for X-ray
analysis were obtained by a CDCl3 solution layered with n-pentane,
at -20 °C. Anal. Calcd for C19H21FeNOS: C, 62.13; H, 5.76; N,
3.81. Found: C, 62.22; H, 5.84; N, 3.72. IR (CH2Cl2): ν(CO) 1932
IR (CH2Cl2): ν(CO) 1965 (vs), 1782 (s), ν(CRN) 1654 (m) cm-1
.
1H NMR (CDCl3): δ 5.01, 4.61 (s, 10 H, Cp); 3.74, 2.79 (m, 2 H,
CγCH2); 3.68, 3.35 (s, 6 H, NMe); 1.80, 1.70 (m, 4 H, Cγ-
CH2CH2CH2); 1.21 (m, 3 H, CγCH2CH2CH2CH3). 13C{1H} NMR
(CDCl3): δ 264.9 (µ-CO); 226.8 (CR); 211.3 (CO); 199.1 (Cγ);
91.9 (Câ); 89.5, 89.1 (Cp); 51.5, 33.9, 24.6 (CH2); 45.4, 43.9 (NMe);
13.7 (CγCH2CH2CH2CH3).
1
(vs), ν(CâCγ) 1516 (w) cm-1. H NMR (CDCl3): δ 7.17-7.10 (3
H, Me2C6H3); 5.83 (s, 1 H, CâH); 4.69 (s, 5 H, Cp); 3.61 (s, 3 H,
NMe); 2.24 (s, 3 H, CγMe); 2.24, 2.03 (s, 6 H, Me2C6H3). 13C{1H}
NMR (CDCl3): δ 249.6 (CR); 217.3 (CO); 198.0 (Cγ); 145.3 (ipso-
Me2C6H3); 133.2, 132.9, 129.0, 128.6, 127.5 (Me2C6H3); 131.6 (Câ);
82.9 (Cp); 47.3 (NMe); 26.0 (CγMe); 19.6 (Me2C6H3).
3g (yield: 76%, color: green). Anal. Calcd for C18H19Fe2NO2-
Se: C, 45.80; H, 4.06; N, 2.97. Found: C, 44.69; H, 3.99; N, 2.90.
Compound 6b was obtained as secondary product in the reaction
of 1c with S8/NaH described above and isolated by chromatography
as a gray band by using diethyl ether as eluent. Yield: 17%. Anal.
Calcd for C20H21FeNO3S: C, 58.40; H, 5.15; N, 3.41. Found: C,
58.30; H, 5.02; N, 3.51. IR (CH2Cl2): ν(CO) 1946 (vs), 1712 (m),
IR (CH2Cl2): ν(CO) 1973 (vs), 1787 (s), ν(CRN) 1654 (m) cm-1
.
1H NMR (CDCl3): δ 6.13 (m, 1 H, OH); 5.92, 5.65 (m, 2 H, CH2-
OH); 4.93, 4.65 (s, 10 H, Cp); 3.66, 3.18 (s, 6 H, NMe). 13C{1H}
NMR (CDCl3) δ 263.1 (µ-CO); 225.4 (CR); 214.0 (CO); 200.2 (Cγ);
90.1 (Câ); 89.4, 88.5 (Cp); 69.4 (CH2); 45.1, 44.5 (NMe).
Synthesis of [Fe2{µ-η1:η3-Cγ(Me)Câ(O)CRN(Me)(Xyl)}(µ-CO-
)(CO)(Cp)2] (4). A THF solution (20 mL) of 1a (250 mg, 0.395
mmol) was treated with Me3NO (148 mg, 1.97 mmol) and NaH
(96 mg, 4.00 mmol). The mixture was stirred for 1 h, then it was
filtered on an alumina pad. Solvent removal and chromatography
on alumina gave a green band corresponding to 4, collected by
using a mixture of THF and MeOH as eluent (19:1, v:v). Yield:
58 mg, 29%. Crystals suitable for X-ray analysis were collected
by a diethyl ether solution layered with petroleum ether (bp 40-
60 °C), at -20 °C. Anal. Calcd for C25H25Fe2NO3: C, 60.15; H,
5.05; N, 2.81. Found: C, 60.18; H, 4.93; N, 2.87. IR (CH2Cl2):
ν(CO) 1945 (vs), 1777 (s), ν(CRN) 1550 (m) cm-1. IR (KBr
pellets): ν(CâO) 1465 (m) cm-1. 1H NMR (CDCl3): δ 7.33-7.10
(m, 3 H, Me2C6H3); 4.88, 4.22 (s, 10 H, Cp); 3.59 (s, 3 H, CγMe);
3.44 (s, 3 H, NMe); 2.34, 2.10 (s, 6 H, Me2C6H3). 13C{1H} NMR
(CDCl3): δ 275.7 (µ-CO); 258.9 (CR); 219.2 (CO); 184.5 (Cγ);
156.9 (Câ); 143.2 (ipso-Me2C6H3); 138.7, 136.0, 129.3, 128.7, 128.1
(Me2C6H3); 88.5, 86.6 (Cp); 46.3 (NMe); 35.0 (CγMe); 18.1, 17.5
(Me2C6H3).
1
ν(CâCγ) 1512 (w) cm-1. H NMR (CDCl3): δ 7.81, 6.79 (s, 1 H,
CâH); 7.18-7.10 (3 H, Me2C6H3); 4.77, 4.14 (s, 5 H, Cp); 3.85,
3.71 (s, 3 H, CO2Me); 3.69, 3.53 (s, 3 H, NMe); 2.37, 2.32, 2.24,
2.00 (s, 6 H, Me2C6H3). E/Z ratio 2:1. 13C{1H} NMR (CDCl3): δ
253.0, 248.3 (CR); 215.7 (CO); 179.1 (Cγ); 164.0 (CO2Me); 149.1,
141.5 (ipso-Me2C6H3); 136.8-127.8 (Me2C6H3); 135.6, 134.7 (Câ);
83.4, 82.9 (Cp); 52.6, 52.5 (CO2Me); 48.2, 43.8 (NMe); 18.4, 18.0,
17.7, 17.3 (Me2C6H3).
Synthesis of [Fe(Cp)(CO){C(R′)C(H)C{N(Me)(R)}S}] (R )
Me, R′ ) Me, 7a; R ) Me, R′ ) Tol, 7b; R ) Me, R′ ) CO2-
Me, 7c; R ) p-C6H4-CN, R′ ) Tol, 7d; R ) 4-C6H4OMe, R′ )
Me, 7e). Compound 1f (75 mg, 0.137 mmol) was dissolved in THF
(10 mL), and S8 (450 mg, 1.76 mmol) was added. The mixture
was treated with NaH (33 mg, 1.38 mmol) and stirred for 45 min.
Then, the mixture was filtered on alumina. Solvent removal and
chromatography on alumina, with CH2Cl2 as eluent, afforded 7a
as a red fraction. Yield: 37 mg, 84%. Anal. Calcd for C12H15-
FeNOS: C, 57.00; H, 5.45; N, 5.05. Found: C, 57.12; H, 5.39; N,
1
5.11. IR (CH2Cl2): ν(CO) 1924 (vs), ν(CdC) 1527 (s) cm-1. H
NMR (acetone-d6): δ 7.10 (s, 1 H, CâH); 4.58 (s, 5 H, Cp); 3.40,
3.32 (s, 6 H, NMe); 2.79 (s, 3 H, CγMe). 13C{1H} NMR (acetone-
d6): δ 247.2 (Cγ); 218.0 (CO); 200.3 (CR); 134.3 (Câ); 82.9 (Cp);
41.7, 41.6 (NMe); 38.4 (CγMe). ESI-MS (ES+): 277 m/z.
Synthesis of [Fe(Cp)(CO){CR{N(Me)(Xyl)}Câ(H)Cγ(R′)S}]
(R′ ) Me, 6a; R′ ) CO2Me, 6b). Compound 6a was obtained as

4816 Organometallics, Vol. 25, No. 20, 2006
Busetto et al.
Complexes 7b-e were obtained by the same procedure described
for 7a, by reacting S8/NaH with 1g, 1h, 1m, and 1n, respectively.
Crystals of 7b suitable for X-ray analysis were obtained by a diethyl
ether solution, layered with n-pentane, at -20 °C.
X-ray Crystallography. Crystal data and collection details for
2b‚CH2Cl2, 3a, 4, 6a, and 7b are reported in Table 4. The diffraction
experiments were carried out on a Bruker SMART 2000 diffrac-
tometer (for 2b‚CH2Cl2, 3a, 4, and 7b) and on a Bruker Apex II
diffractometer (for 6a), equipped with a CCD detector using Mo
KR radiation. Data were corrected for Lorentz polarization and
absorption effects (empirical absorption correction SADABS).17
Structures were solved by direct methods and refined by full-matrix
least-squares based on all data using F2.18 Non-H atoms were refined
anisotropically, unless otherwise stated. H atoms were placed in
calculated positions, except H(8) in 6a and 7b, which were located
in the Fourier map. H atoms were treated isotropically using the
1.2-fold Uiso value of the parent atom except methyl protons, which
were assigned the 1.5-fold Uiso value of the parent C atom. The
Tol group and the CH2Cl2 molecule in 2b‚CH2Cl2 and Cp ligand
in 7b are disordered. Disordered atomic positions were split and
refined using one occupancy parameter per disordered group.
7b (yield: 85%; color: orange). Anal. Calcd for C18H19FeNOS:
C, 61.20; H, 5.42; N, 3.96. Found: C, 61.25; H, 5.44; N, 4.02. IR
1
(CH2Cl2): ν(CO) 1925 (vs), ν(CdC) 1526 (m) cm-1. H NMR
(CDCl3): δ 7.25, 7.11 (d, 4 H, 3JHH ) 8.05 Hz, MeC6H4); 7.11 (s,
1 H, CâH); 4.41 (s, 5 H, Cp); 3.48, 3.31 (s, 6 H, NMe); 2.35 (s, 3
H, MeC6H4). 13C{1H} NMR (CDCl3): δ 244.3 (Cγ), 217.5 (CO),
199.7 (CR), 153.9 (ipso-MeC6H4); 136.0, 128.1, 124.8 (MeC6H4);
133.8 (Câ); 83.5 (Cp); 43.2, 42.6 (NMe); 21.1 (MeC6H4).
7c (yield: 88%; color: orange). Anal. Calcd for C13H15-
FeNO3S: C, 48.62; H, 4.71; N, 4.36. Found: C, 48.71; H, 4.69;
N, 4.25. IR (CH2Cl2): ν(CO) 1944 (vs), 1693 (m), ν(CdC) 1536
1
(s) cm-1. H NMR (acetone-d6): δ 7.22 (s, 1 H, CâH); 4.58 (s, 5
H, Cp); 3.73 (s, 3 H, CO2Me); 3.47, 3.40 (s, 6 H, NMe). 13C{1H}
NMR (acetone-d6): δ 221.7 (Cγ); 216.9 (CO); 201.2 (CR); 179.3
(CO2Me); 134.0 (Câ); 82.8 (Cp); 50.6 (CO2Me); 43.0, 42.5 (NMe).
7d (yield: 75%; color: orange). Anal. Calcd for C24H20FeN2-
OS: C, 65.46; H, 4.58; N, 6.36. Found: C, 65.57; H, 4.62; N,
6.28. IR (CH2Cl2): ν(CtN) 2217 (w), ν(CO) 1934 (vs), ν(CdC)
1604 (s) cm-1. 1H NMR (CDCl3): δ 7.66-7.03 (m, 8 H, CNC6H4
and MeC6H4); 6.88 (s, 1 H, CâH); 4.44 (s, 5 H, Cp); 3.74 (s, 3 H,
NMe); 2.29 (s, 3 H, MeC6H4). 13C{1H} NMR (CDCl3): δ 249.9
(Cγ), 216.5 (CO), 200.6 (CR), 153.4 (ipso-MeC6H4); 150.0 (ipso-
CNC6H4); 135.9 (Câ); 133.5, 128.1, 126.3, 124.7 (MeC6H4); 118.0
(C6H4CN); 83.8 (Cp); 43.3 (NMe); 21.0 (MeC6H4).
Acknowledgment. We thank the Ministero dell’Univer-
sita` e della Ricerca Scientifica e Tecnologica (MIUR) (project:
“New strategies for the control of reactions: interactions of
molecular fragments with metallic sites in unconventional
species”) and the University of Bologna for financial support.
Supporting Information Available: Crystallographic data for
compounds 2b‚CH2Cl2, 3a, 4, 6a, and 7b in CIF format. This
material is available free of charge via the Internet at
http://pubs.acs.org.
7e (yield: 76%; color: brown). Anal. Calcd for C18H19-
FeNO2S: C, 58.55; H, 5.19; N, 3.79. Found: C, 58.57; H, 5.22;
N, 3.66. IR (CH2Cl2): ν(CO) 1926 (vs), ν(CdC) 1607 (m) cm-1
.
OM060550R
1H NMR (CDCl3): δ 7.10, 6.90 (m, 4 H, C6H4); 6.69 (s, 1 H, CâH);
4.61 (s, 5 H, Cp); 3.82 (s, 3 H, OMe); 3.65 (s, 3 H, NMe); 2.79 (s,
3 H, CγMe). 13C{1H} NMR (CDCl3): δ 249.0 (Cγ); 217.1 (CO);
201.5 (CR); 158.5, 139.6 (ipso-C6H4OMe); 136.5 (Câ); 126.7, 114.5
(C6H4OMe); 82.8 (Cp); 55.4 (OMe); 43.5 (NMe); 38.9 (CγMe).
(17) Sheldrick, G. M. SADABS, Program for empirical absorption
correction; University of Go¨ttingen: Germany, 1996.
(18) Sheldrick, G. M. SHELX97, Program for crystal structure determi-
nation; University of Go¨ttingen: Germany, 1997.