Synthesis of Alkynechalcogenolato Complexes of Titanocene(IV) and Samarocene(III) and Formation of a Ti2Ni Trinuclear Cluster [Cp2Ti(μ-SC≡CPh)2]2Ni

Article abstract of DOI:10.1021/ic980901x

Reactions between (C₅H₄R')₂TiCl₂ and 2 equiv of LiEC≡CR generated a series of alkynethiolato and alkyneselenolato complexes of titanocene(IV), (C₅H₄R')₂Ti(EC≡CR)₂ in high yields (1, R = Ph. R' = H, E = S; 2, R = p-C₆H₄CH₃, R' = H, E = S; 3, R = ^tBu, R' = H, E = S; 4, R = Ph, R' = Me, E = S; 5, R = Ph, R' = H, E = Se). Complex 1 reacted with 1/2 equiv of Ni(cod)₂ to give a linear Ti₂Ni trimetallic complex, [Cp₂Ti(μ-SC≡CPh)₂]₂Ni (6), in which the Ni atom links two Cp₂Ti(SC≡CPh)₂ units through interactions with thiolate sulfur bridges. Treatment of Cp*₂Sm(μ-Cl)₂Li(OEt₂)₂ with 2 equiv of LiSC≡CPh and TMEDA resulted in [Li-(tmeda)₂][Cp*₂Sm(SC≡CPh)₂] (7). The structures of complexes 4, 5, 6, and 7 were determined by X-ray diffraction analysis.

Full text of DOI:10.1021/ic980901x

Inorg. Chem. 1998, 37, 6773-6779
6773
Synthesis of Alkynechalcogenolato Complexes of Titanocene(IV) and Samarocene(III) and
Formation of a Ti2Ni Trinuclear Cluster [Cp2Ti(µ-SCtCPh)2]2Ni
Hiroyasu Sugiyama, Yuji Hayashi, Hiroyuki Kawaguchi, and Kazuyuki Tatsumi*
Research Center for Materials Science, and Department of Chemistry, Graduate School of Science,
Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
ReceiVed July 28, 1998
Reactions between (C5H4R′)2TiCl2 and 2 equiv of LiECtCR generated a series of alkynethiolato and
alkyneselenolato complexes of titanocene(IV), (C5H4R′)2Ti(ECtCR)2 in high yields (1, R ) Ph, R′ ) H, E ) S;
t
2, R ) p-C6H4CH3, R′ ) H, E ) S; 3, R ) Bu, R′ ) H, E ) S; 4, R ) Ph, R′ ) Me, E ) S; 5, R ) Ph, R′ )
1
H, E ) Se). Complex 1 reacted with /2 equiv of Ni(cod)2 to give a linear Ti2Ni trimetallic complex, [Cp2Ti(µ-
SCtCPh)2]2Ni (6), in which the Ni atom links two Cp2Ti(SCtCPh)2 units through interactions with thiolate
sulfur bridges. Treatment of Cp*2Sm(µ-Cl)2Li(OEt2)2 with 2 equiv of LiSCtCPh and TMEDA resulted in [Li-
(tmeda)2][Cp*2Sm(SCtCPh)2] (7). The structures of complexes 4, 5, 6, and 7 were determined by X-ray diffraction
analysis.
Introduction
As an extension of our study on transition metal thiolates,6
we began to investigate the behavior of alkynethiolates and
Transition metal complexes of alkoxides, thiolates, seleno-
lates, and tellurolates constitute an important domain in
inorganic chemistry.1 Although it is well recognized that redox-
active chalcogenolate ligands play significant roles in modula-
tion of electronic properties of transition metals, they are often
regarded as reactively inert and have been used as innocent
spectator ligands. For instance, chalcogenolates carrying bulky
substituents have facilitated isolation of coordinatively unsatur-
ated transition metal complexes.2 Chelates containing both a
chalcogen (E)-donor and a P-donor (or an N-donor) have also
appeared, and the E-P (or N) hybrid ligands have contributed
to expansion of the scope of chalcogenolate chemistry.3,4 On
the other hand, the most notable reaction of thiolate ligands on
transition metals is perhaps C-S bond cleavage, which has
frequently been observed for alkanethiolate complexes.5
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10.1021/ic980901x CCC: $15.00 © 1998 American Chemical Society
Published on Web 12/01/1998

6774 Inorganic Chemistry, Vol. 37, No. 26, 1998
Sugiyama et al.
Deuterated solvents were dried over Na (C6D6) or CaH2 (CDCl3 and
CD3CN) and then vacuum-transferred prior to use. The 4-aryl-1,2,3-
thiadiazole,7c Cp2TiCl2,7g and Cp*2Sm(µ-Cl)2Li(OEt2)27h were prepared
based on the literature with a slight modification. The NMR spectra
were recorded on a Varian Unity Inova 500 spectrometer operating at
alkyneselenolates bound to transition metals. Having a carbon-
carbon triple bond in close proximity to a chalcogen atom,
alkynechalcogenolate ligands may exhibit structural diversity
and unusual reactivity upon coordination to transition metals.
As the first report of our study of alkynechalcogenolate
complexes, we describe here the synthesis and characterization
of a series of titanocene(IV) alkynethiolate and alkyneselenolate
complexes as well as a samarocene(III) alkynethiolate, which
are the first fully characterized transition metal alkynechalco-
genolate complexes. Also reported is the reaction of Cp2Ti-
(SCtCR)2 (Cp ) η5-C5H5) with Ni(cod)2 (cod ) 1,5-
cyclooctadiene) to give [Cp2Ti(SCtCR)2]2Ni.
500 MHz for H, at 126 MHz for 13C. H and 13C{1H} spectra were
referenced to TMS by using the residual protons or carbons of
deuterated solvents (1H: C6D6, δ 7.2 ppm; CD3CN, δ 1.97 ppm. 13C:
C6D6, δ 128.5 ppm). Some 13C{1H} NMR spectra were measured under
the presence of Cr(acac)3 as a relaxation reagent to detect the alkynyl
13C resonances. IR and UV-vis spectra were recorded on a Perkin-
Elmer 2000 FT-IR spectrometer and a JASCO V-500 spectrometer,
respectively. Elemental analyses were performed on a LECO CHNS-
932 microanalyzer.
1
1
While alkali metal salts of alkynechalcogenolate have been
known for some time,7 there are only a few examples of their
transition metal complexes. Alkynethiolate complexes, CpRu-
(SCtCR)L2 and L2Pt(SCtCR)2 were prepared from reactions
of LiSCtCR (R ) Ph, SiMe3, (C5H5)Fe(C5H4)) with CpRuClL2
n
Preparation of LiSCtCtBu. A hexane solution of BuLi (1.6 M,
6.2 mL, 9.92 mmol) was added to an Et2O (20 mL) solution of tBuCt
CH (1.25 mL, 10.2 mmol) at 0 °C, and the reaction mixture was stirred
for 1 h at room temperature, which was then added dropwise to a cold
Et2O (20 mL, -80 °C) suspension of S8 (320 mg, 1.25 mmol) by
syringe. The reaction mixture was warmed to room temperature and
was stirred for 4 h. The volatiles were removed under reduced pressure.
The white powder was dissolved into THF (20 mL) and was stored in
Schlenk flask as a ca. 0.5 M solution of LiSCtCtBu. 1H NMR (CD3-
CN, 500 MHz, 20 °C): δ 1.10 (s, 9H, C(CH3)3). IR (KBr, Nujol mull
(cm-1)): 2132 (s, ν(CtC)).
1
(L ) PPh3, PMe3) and L2PtCl2 (L ) PPh3, /2 dppe), respec-
tively, while the Fisher-type carbene complexes M(CO)5{dCPh-
(OEt)} (M ) Cr, W) were found to react with LiECtCPh and
gaseous HCl to give M(CO)5{EdCHC(Ph)dC(OEt)Ph} (E )
S, Se).8,9 Interestingly the treatment of [(µ-S2)Fe2(CO)6] with
LiCtCR and subsequent addition of alkyl halide or acyl halide
gave rise to alkynethiolate complexes, [(µ-SCtCR)(µ-SR′)Fe2-
(CO)6] (R ) Ph, n-C4H9, n-C5H11, SiMe3; R′ ) Me, Et, PhCH2,
CH2C(O)CH3, CH3C(O), (CH3)3CC(O)).10 However, crystal
structures of these alkynechalcogenolate complexes have not
been determined. The cadmium complex, [Cd(SeCtCPh)2-
(tmeda)]2, is the sole example of structurally characterized
alkynechalcogenolate complex, which was synthesized by the
reaction between Cd(CtCPh)2 and metallic Se.11
Preparation of LiSCtCR (R ) Ph, p-C6H4CH3). A THF solution
of LiN(SiMe3)2 (1.0 M, 2.1 mL, 2.1 mmol) was added to a cold THF
(10 mL) solution of 4-phenyl-1,2,3-thiadiazole (357 mg, 2.2 mmol) at
0 °C and were stirred for 1.5 h. The volatiles were removed under
reduced pressure. The residue was washed with hexane (10 mL) and
was dried in vacuo to give LiSCtCPh as a white powder. The
analogous treatment of 4-p-tolyl-1,2,3-thiadiazole with 1 equiv of LiN-
(SiMe3)2, gave LiSCtC(p-C6H4CH3) as a white powder.
Synthesis of (C5H4R′)2Ti(SCtCR)2 (1, R ) Ph, R′ ) H; 2, R )
t
p-C6H4CH3, R′ ) H; 3, R ) Bu, R′ ) H; 4, R ) Ph, R′ ) Me). A
Experimental Section
series of alkynethiolate complexes of titanocene were synthesized in a
similar manner, and only the preparation of 1 is described here. A THF
(40 mL) solution of LiSCtCPh (2.1 mmol, prepared as described
above) was added to a THF (20 mL) solution of Cp2TiCl2 (249 mg,
1.0 mmol) at 0 °C. The dark green reaction mixture was stirred for 4
h at room temperature before the solvent was removed in vacuo. The
residue was extracted with toluene (70 mL) and centrifuged to remove
LiCl, and the toluene was evaporated to leave a dark green solid. This
crude product was recrystallized from THF/hexane to give 1 as dark
green crystals in 93% yield.
General. The standard Schlenk techniques were used for all
manipulations. The solvents (THF, Et2O, hexane, and toluene) were
distilled from sodium/benzophenone ketyl under an Ar atmosphere.
(6) (a) Tatsumi, K.; Takeda, Y.; Sekiguchi, M.; Kohsaka, M.; Nakamura,
A. Angew. Chem. 1985, 97, 355; Angew. Chem., Int. Ed. Engl. 1985,
24, 332. (b) Tatsumi, K.; Sekiguchi, Y.; Nakamura, A.; Cramer, R.
E.; Rupp, J. J. Angew. Chem. 1986, 98, 95; Angew. Chem., Int. Ed.
Engl. 1986, 25, 86. (c) Tatsumi, K.; Sekiguchi, Y.; Sebata, M.;
Nakamura, A.; Cramer, R. E.; Chung, T.; Angew. Chem. 1989, 101,
83; Angew. Chem., Int. Ed. Engl. 1989, 28, 98. (d) Tatsumi, K.;
Matsubara, I.; Sekiguchi, Y.; Mealli, C. Inorg. Chem. 1989, 28, 773.
(e) Tatsumi, K.; Matsubara, I.; Inoue, Y.; Nakamura, A.; Miki, K.;
Kasai, N. J. Am. Chem. Soc. 1989, 111, 7766. (f) Tatsumi, K.;
Matsubara, I.; Inoue, Y.; Nakamura, A.; Cramer, R. E.; Taogoshi, G.
J. Golen, J. A.; Gilje, J. W. Inorg. Chem. 1990, 29, 4928. (g) Tatsumi,
K.; Inoue, Y.; Nakamura, A. J. Organomet. Chem. 1993, 444, C25.
(h) Tatsumi, K.; Kawaguchi, H.; Matsubara, I.; Nakamura, A.; Miki,
K.; Kasai, N. Inorg. Chem. 1993, 32, 2604. (i) Kawaguchi, H.;
Tatsumi, K.; Cramer, R. E. Inorg. Chem. 1996, 35, 4391.
1
1, dark green crystals, yield 93%. H NMR (C6D6, 500 MHz, 20
°C): δ 5.89 (s, 10H, C5H5), 6.98-7.04 (m, 6H, o,p-C6H5), 7.53 (m,
4H, m-C6H5). 13C{1H} NMR (C6D6, 126 MHz, 20 °C, with Cr(acac)3):
δ 94.2 (SC2Ph), 108.3 (SC2Ph), 115.5 (C5H5), 126.9 (C6H5), 127.7
(C6H5), 129.0 (C6H5), 131.8 (C6H5). IR (Nujol mull, KBr (cm-1)): 2144
(m, ν(CtC)). UV-vis (THF, λmax (nm), ꢀmax (M-1 cm-1)): 595 (3.9
× 103), 450 (2.6 × 103), 398 (2.7 × 103), 289 (2.1 × 104). Anal. Calcd
for C26H20S2Ti: C, 70.26; H, 4.54; S, 14.43. Found: C, 70.22; H, 4.62;
S, 13.94.
(7) (a) Brandsma, L. PreparatiVe Acetylene Chemistry, 2nd ed.; Studies
in Organic Chemistry 34; Elsevier: Amsterdam, 1988; pp 129-141.
(b) Schmidt, M.; Portschka, V. Naturwissenschaften 1963, 50, 302.
(c) Raap, R.; Micetich, R. G. Can. J. Chem. 1967, 46, 1057. (d) Raap,
R. Can. J. Chem. 1968, 46, 2251. (e) Lalezari, I.; Shafiee, A.; Yalpani,
M. Tetrahedron Lett. 1969, 5105. (f) Shafiee, A.; Fanaii, G. Synthesis
1984, 512. (g) King, R. G. Organometallic Syntheses; Academic
Press: San Diego, 1965; p 75. (h) Jenske, G.; Lauke, H.; Mauermann,
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1985, 107, 8091-8103.
1
2, dark green crystals, yield 83%. H NMR (C6D6, 500 MHz, 20
°C): δ 2.06 (s, 6H, C6H4CH3), 5.91 (s, 10H, C5H5), 6.87 (d, 4H, o-C6H4-
CH3, Jom ) 7.7 Hz), 7.50 (d, 4H, m-C6H4CH3). 13C{1H} NMR (C6D6,
126 MHz, 20 °C, with Cr(acac)3): δ 21.8 (C6H4CH3), 93.5 (SC2C6H4-
CH3), 108.8 (SC2C6H4CH3), 115.5 (C5H5), 124.0 (C6H4CH3), 129.8
(C6H4CH3), 131.8 (C6H4CH3), 137.5 (C6H4CH3). IR (Nujol mull, KBr
(cm-1)): 2143 (m, ν(CtC)). UV-vis (THF, λmax (nm), ꢀmax (M-1
cm-1)): 599 (8.2 × 103), 457 (5.6 × 103), 391 (5.8 × 103), 287 (4.5
× 104). Anal. Calcd for C28H24S2Ti: C, 71.17; H, 5.12; S, 13.57.
Found: C, 70.81; H, 5.42; S, 13.47.
3, red-purple plates, yield 97%. 1H NMR (C6D6, 500 MHz, 20 °C):
δ 1.37(s, 18H, C(CH3)3), 5.88 (s, 10H, C5H5). 13C{1H} NMR (C6D6,
126 MHz, 20 °C): δ 30.5 (C(CH3)3), 32.4 (C(CH3)3), 82.0 (SCtC),
115.2 (C5H5), 117.7 (SCtC). IR (Nujol mull, KBr (cm-1)): 2145 (w,
(8) (a) Weigand, W. Z. Naturforsch. B: Chem. Sci. 1991, 46, 1333. (b)
Weigand, W.; Robl, C. Chem. Ber. 1993, 126, 1807.
(9) (a) Raubenheimer, H. G.; Kruger, G. J.; Marais, C. F. J. Chem. Soc.,
Chem. Commun. 1984, 634. (b) Raubenheimer, H. G.; Kruger, G. J.;
Marais, C. F.; Hattingh, J. T. Z.; Linford, L.; Rooyen, P. H. v. J.
Organomet. Chem. 1988, 355, 337. (c) Raubenheimer, H. G.; Kruger,
G. J.; Marais, C. F.; Otte, R.; Hattingh, J. T. Z. Organometallics 1988,
7, 1853. (d) Raubenheimer, H. G.; Kruger, G. J.; Linford, L.; Marais,
C. F.; Otte, R.; Hattingh, J. T. Z.; Lombard, A. J. Chem. Soc., Dalton
Trans. 1989, 1565.
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K. L.; Wright, D. S. J. Chem. Soc., Dalton Trans. 1996, 2183.

Synthesis of Alkynechalcogenolato Complexes
Inorganic Chemistry, Vol. 37, No. 26, 1998 6775
ν(CtC)). UV-vis (THF, λmax (nm), ꢀmax (M-1 cm-1)): 574 (6.1 ×
103), 415 (4.1 × 103), 292 (1.8 × 104). Anal. Calcd for C22H28S2Ti:
C, 65.33; H, 6.98; S, 15.86;. Found: C, 63.53; H, 6.96; S, 15.42.
62.22; H, 7.83; N, 6.05; S, 6.92. Found: C, 62.02; H, 8.19; N, 5.89; S,
6.91. Crystals suitable for X-ray analysis were grown from toluene at
0 °C.
1
X-ray Crystallographic Study. X-ray-quality crystals of 4, 5, 6,
and 7 were obtained as described above. The crystals were manipulated
and mounted in capillaries in Schlenk tubes. Diffraction data were
collected at room temperature on a Rigaku AFC 7R diffractometer
equipped with graphite-monochromatized Mo KR radiation (λ )
0.710 69 Å). The crystal system and cell parameters were initially
determined from 20 machine-centered reflections (6° < 2θ < 13°)
elected by an automated peak search routine. Refined cell dimensions
and their standard deviations were obtained by least-squares refinements
of 25 higher-angle reflections (20° < 2θ < 25°). Three standard
reflections were recorded every 150 reflections, which showed no
significant decay over the duration of the data collections. The
diffraction data were corrected for Lorentz and polarization effects,
and absorption corrections based on y-scans were applied. The data
were processed using the TEXSAN package. The metal atom positions
of 4, 5, and 6 along with some heavy atom positions were located
unambiguously by direct methods with a SHELLX-86 program, while
the structure of 7 was solved by the Patterson method with a DIRDIF92
PATTY program. In each case, the remaining non-hydrogen atoms were
found in subsequent difference Fourier maps, and the structures were
refined by full-matrix least-squares based on the reflections with I >
3σ(I). All metal and chalcogene atoms were refined using anisotropic
thermal parameters. The number of anisotoropically refined carbon
atoms was set so as to maintain a reasonable data/variable ratio for
each structure. Thus, phenyl carbons of 4 and 7, TMEDA carbons of
7, and solvent molecules of 6‚2toluene were refined isotropically. All
hydrogen atoms were put at idealized positions. Crystallographic data
and final R indices are summarized in Table 1, and complete
crystallographic details are given in the Supporting Information.
4, dark green crystals, yield 75%. H NMR (C6D6, 500 MHz, 20
°C): δ 1.91 (s, 6H, C5H4CH3), 5.82 (t, 4H, C5H4CH3, J ) 2.58 Hz),
6.00 (t, 4H, C5H4CH3), 6.97-7.03 (m, 6H, o,p-C6H5), 7.53 (m, 4H,
m-C6H5). 13C{1H} NMR (C6D6, 126 MHz, 20 °C, Cr(acac)3): δ 16.3
(C5H4CH3), 94.4 (SC2Ph), 107.0 (SC2Ph), 116.2 (C5H4CH3), 116.5
(C5H4CH3), 117.3 (C5H4CH3), 127.0 (C6H5), 127.6 (C6H5), 129.0 (C6H5),
131.9 (C6H5). IR (Nujol mull, KBr (cm-1)): 2141 (m, ν(CtC)). UV-
vis (THF, λmax (nm), ꢀmax (M-1 cm-1)): 589 (4.4 × 103), 450 (3.2 ×
103), 401 (3.6 × 103), 288 (2.7 × 104). Anal. Calcd for C28H24S2Ti:
C, 71.17; H, 5.12; S, 13.57. Found: C, 70.87; H, 5.04; S, 13.46. Crystals
suitable for X-ray analysis of 4 were grown from toluene/hexane at
ambient temperature.
n
Preparation of LiSeCtCPh. A hexane solution of BuLi (1.6 M,
4 mL, 6.4 mmol) was added to a THF (10 mL) solution of PhCtCH
(0.75 mL, 6.8 mmol) at 0 °C and was stirred for 1 h at room
temperature. This resultant THF solution of LiCtCPh was added
dropwise to a THF (30 mL) suspension of gray Se (514 mg, 6.5 mmol)
at -80 °C, and the resultant mixture was stirred for 4 h at room
temperature. The solvents were evaporated to dryness, and the residue
was washed with hexane (10 mL) to give a white powder. The crude
product was recrystallized from toluene to give PhCtCSeLi(thf)x in
95% yield as white micro crystals, where x was estimated to be 1.5
1
according to the H NMR spectrum in CD3CN.
Synthesis of Cp2Ti(SeCtCPh)2 (5). This compound was synthe-
sized in a manner analogous to that described for the corresponding
thiolate species, using 249 mg (1.0 mmol) of Cp2TiCl2 and 2.05 mmol
of LiSeCtCPh. The reaction mixture was stirred for 3 h, and a standard
1
work up gave 5 as dark green microcrystals in 85% yield. H NMR
(C6D6, 500 MHz, 20 °C): δ 5.87 (s, 10H, C5H5), 6.98-7.01 (m, 6H,
o,p-C6H5), 7.56 (m, 4H, m-C6H5). 13C{1H} NMR (C6D6, 126 MHz, 20
°C, with Cr(acac)3): δ 82.9 (SC2Ph), 113.5 (SC2Ph), 114.0 (C5H5),
126.4 (C6H5), 128.0 (C6H5), 129.0 (C6H5), 132.2 (C6H5). IR (KBr pellet
(cm-1)): 2133 (m, ν(CtC)). UV-vis (THF, λmax (nm), ꢀmax (M-1
cm-1)): 631 (8.2 × 103), 453 (5.4 × 103), 299 (4.8 × 104). Anal. Calcd
for C26H20Se2Ti: C, 58.02; H, 3.75. Found: C, 57.97; H, 3.72. Crystals
suitable for X-ray analysis of 5 were grown from toluene/hexane at
ambient temperature.
Results and Discussion
There are two different synthetic routes to lithium alkyne-
thiolates. One is the reaction of a preformed lithium alkynide
with elemental sulfur in an appropriate polar solvent (eq 1).
The other makes use of an N2 elimination reaction of 1,2,3-
thiadiazoles with LiN(SiMe3)2 in THF (eq 2).7 For the synthesis
of lithium alkyneselenolates, eq 1 can be modified by replacing
S8 with gray selenium (eq 3).
Synthesis of [Cp2Ti(µ-SCtCPh)2]2Ni (6). A toluene (30 mL)
solution of Ni(cod)2 (65 mg, 0.24 mmol) was added to a toluene (30
mL) solution of 1 (210 mg, 0.47 mmol). The dark green solution
immediately became purple. After it had been stirred for 2 days at room
temperature, the reaction mixture was centrifuged to remove insoluble
material. Concentration and cooling of the solution afforded [Cp2Ti-
(µ-SCtCPh)2]2Ni (6) in 33% yield as black purple microcrystals.1H
NMR (C6D6, 500 MHz, 20 °C): δ 5.75 (s, 20H, C5H5), 6.96-7.01 (m,
12H, o,p-C6H5), 7.64 (m, 8H, m-C6H5). IR (KBr pellet (cm-1)): 2150
(m, n(CtC)). UV-vis (toluene, λmax (nm), ꢀmax (M-1 cm-1)): 730 (3.0
× 103), 530 (9.4 × 103), 391 (1.6 × 104), 348 (2.0 × 104). Anal. Calcd
for C59H49S4Ti2Ni (as 6‚toluene): C, 68.09; H, 4.75; S, 12.32. Found:
C, 68.17; H, 4.57; S, 12.61. Crystals suitable for X-ray analysis of 6
were grown from a toluene/hexane solution at room temperature.
Weigand and Raubenheimer prepared LiECtCR (E ) S, Se;
R ) Ph, SiMe3, etc.) using the method analogous to eq 1 for
the reactions with CpRuClL2 (L ) PPh3, PMe3), L2PtCl2 (L )
PPh3, 1/2dppe), and carbene complexes of chromium and
tungsten.8,9 However the lithium alkynechalcogenolates obtained
from one-pot reactions of equimolar amounts of alkyne, nBuLi,
Synthesis of [Li(tmeda)2][Cp*2Sm(SCtCPh)2] (7). To a THF (20
mL) solution of Cp*2Sm(µ-Cl)2Li(OEt2)2 (406 mg, 0.63 mmol), a THF
(20 mL) solution of LiSCtCPh (1.36 mmol) was added. The yellow
orange reaction mixture was stirred for 4 h at room temperature and
the solvent was removed in vacuo. The residue was extracted with Et2O
(40 mL). After removal of LiCl by centrifugation, TMEDA (1 mL)
was added to the supernatant liquid to form the microcrystals. The
volatiles were removed under reduced pressure. The resulted residue
was recrystallized from toluene (5 mL) to give the pure materials of 7
as orange crystals in 42% yield. 1H NMR (C6D6, 500 MHz, 20 °C): δ
1.67 (s, 30H, C5(CH3)5, ν1/2 ) 13.4 Hz), 2.01 (s, 8H, (CH3)2NCH2, ν1/2
) 5.0 Hz), 2.04 (s, 24H, (CH3)2NCH2, ν1/2 ) 9.4 Hz), 6.56 (brs, 4H,
C6H5, ν1/2 ) 64.2 Hz), 6.76 (brs, 6H, C6H5, ν1/2 ) 25.5 Hz). IR (KBr,
Nujol mull (cm-1)): 2133 (s, ν(CtC)). UV-vis (THF, λmax (nm), ꢀmax
(M-1 cm-1)): 357 (2.5 × 104). Anal. Calcd for C48H72N4S2LiSm: C,
1
and /8S8 or Se was used for the subsequent reactions without
isolation of LiECtCR. Therefore, we reexamined preparation
of lithium alkynechalcogenolates, to find that LiSCtCtBu and
LiSeCtCPh were readily obtained as white solids from the
reactions of the corresponding lithium alkynides with S8 and
gray selenium, respectively. However, in the case of the
treatment of LiCtCPh with S8, the product was strongly reddish
orange colored. Although recrystallization from toluene/hexane

6776 Inorganic Chemistry, Vol. 37, No. 26, 1998
Sugiyama et al.
Table 1. Crystal Data for 4, 5, 6‚2toluene, and 7
4
5
6‚2toluene
7
empirical formula
fw
space group
a, Å
b, Å
C28H24S2Ti
472.52
P21/c (#14)
12.474(2)
12.153(3)
16.072(3)
C26H20Se2Ti
538.26
P1h (#2)
10.489(6)
12.595(7)
9.901(8)
106.53(5)
112.26(5)
99.67(5)
1103(1)
2
1.620
36.98
50.0
0.51-1.00
4117
2151
262
C66H56S4Ti2Ni
1131.91
P21/c (#14)
13.203(2)
16.596(9)
25.794(4)
C48H72N4S2LiSm
926.58
P21 (#4)
18.077(4)
13.904(4)
20.516(5)
c, Å
R, deg
â, deg
γ, deg
V, Å3
Z
102.67(1)
93.19(1)
96.98(2)
2377.1(8)
4
1.320
5.49
5643(3)
4
1.332
7.95
5118(2)
4
1.202
12.64
55.0
0.70-1.00
12249
6798
759
0.042
0.042
1.80
d
calcd, g/cm3
µ, cm-1
2θmax, deg
50.0
45.0
transm factors
no. of indep rflns
no. obsd rflns
no. of refined params
Ra
0.90-1.00
4402
1893
220
0.053
0.054
1.91
0.87-1.00
7708
4478
588
0.043
0.047
2.20
0.042
0.042
1.54
b
RW
GOFc
max. and min. residual
0.30
-0.24
0.57
-0.36
0.41
-0.25
0.74
-0.40
peak in final diff. map, e-/Å3
2
a R ) ∑||Fo| - |Fc||/∑|Fo|. b RW ) [∑w(|Fo| - |Fc|)2/∑w|Fo| ]1/2
.
c GOF ) [∑w(|Fo| - |Fc|)2/(M - N)]1/2, where M ) number of reflections and
N ) number of parameters.
resulted in gradual decoloration, we could not isolate LiSCt
CPh of satisfactory quality. On the other hand, the method based
on eq 2 produced LiSCtCPh successfully as white powders
after standard workup. We also prepared LiSCtC(p-C6H4CH3)
by a similar procedure. Thus we were able to isolate a series of
lithium salts of alkynechalcogenolates in a preparative scale by
choosing proper synthetic routes, and they were used for the
subsequent syntheses of transition metal complexes reported in
this paper.
band arising from the CtC stretching vibration, which appears
at 2144, 2143, 2145 and 2141 cm-1, respectively. These bands
are similar to those of the known η1-(S) alkynethiolate com-
plexes, CpRu(SCtCR)L2 and L2Pt(SCtCR)2 (R ) Ph, SiMe3,
(C5H5)Fe(C5H4); L ) PPh3, PMe3, 1/2dppe) (2127-2142 cm-1).8
We have carried out the reactions of (C5H5)2TiCl2 and (C5H4-
Me)2TiCl2 with 2 equiv of LiSCtCPh, LiSCtC(p-C6H4CH3),
and LiSCtCtBu in THF. In either case, the reaction proceeded
smoothly with the color change from red to dark green for 1, 2
and 4, or to red purple for 3, and the standard work up afforded
bis-alkynethiolate complexes as dark green crystals for 1, 2,
and 4, and as red purple plates for 3.
The alkyneselenolate complex 5 also exhibits a sharp CtC
stretching band at 2133 cm-1 in the IR spectrum, which is
comparable to that observed for [Cd(SeCtCPh)2(tmeda)]2 (2130
1
cm-1).11 In the H NMR spectra of 1-5, the relative intensity
of the proton signals of cyclopentadienyl and alkynethiolate or
alkyneselenolate is consistent with their formulation. In the 13C-
{1H} NMR spectra of 1-4, two alkynyl carbon resonances
appeared at δ 94.2 and 108.3 for 1, δ 93.5 and 108.8 for 2, δ
82.0 and 117.7 for 3, and δ 94.4 and 107.0 for 4. They are
shifted to lower fields compared with the corresponding 13C
resonaces of RCtCH (R ) Ph, δ 77.1 and 83.6; R ) p-C6H4-
CH3, δ 76.4 and 83.8; R ) tBu, δ 66.4 and 93.1). The 13C{1H}
NMR spectrum of 5 exhibits the alkynyl carbon resonances at
δ 82.9 and 113.5, and the difference of the chemical shifts
between the two alkynyl carbons is larger than those of the
alkynethiolate complexes 1-4.
The crystal structures of 4 and 5 were determined by X-ray
analysis, and their molecular views are shown in Figures 1 and
2, respectively. The selected structural parameters of 4 and 5
are summarized in Table 2. The two structures are very much
alike, and alkynyl groups of both thiolato and selenolato ligands
are syn oriented in the crystals. The two phenyl rings in each
structure are situated perpendicular to each other with the
dihedral angles 118.8° for 4 and 104.4° for 5. The intramolecular
p-p stacking of these phenyl groups did not occur. The Ti-S
bond distances of 2.448(2) and 2.427(2) Å) for 4 are close to
those of Cp2Ti(SPh)2 (2.4395(8) and 2.424(8) Å), while the
S-Ti-S angle of 95.79(8) ° is slightly smaller than that of Cp2-
It has been known that treatment of LiSCtCR with electro-
philes E+ tends to produce an appreciable amounts of high-
boiling residues, which may in part result from further reactions
of preformed thioketenes, RC(E)dCdS.7a Although the acidic
Ti(IV) center could act as an electrophile, the reactions of
LiSCtCR with (C5H4R′)2TiCl2 at room temperature generated
a series of bis-alkynethiolate complexes in high yields, and the
side reactions due to the formation of thioketenes were not
observed.
The analogous reaction between Cp2TiCl2 and 2 equiv of
LiSeCtCPh also went smoothly, generating the bis-alkyne-
selenolato complex Cp2Ti(SeCtCPh)2 (5) in 84% yield. The
IR spectra of 1, 2, 3, and 4 are featured by a common sharp

Synthesis of Alkynechalcogenolato Complexes
Inorganic Chemistry, Vol. 37, No. 26, 1998 6777
tances (2.588(2) and 2.563(2) Å) of 5 resemble those of (MeCp2-
Ti)2Se4 (2.563(1) and 2.542(1) Å).13 The geometric parameters
of the SCtCPh and SeCtCPh groups are normal. The CtC
distances for 4 and 5 fall in the normal range of carbon-carbon
triple bonds and the both S-C-C and Se-C-C bonds are
practically linear. Therefore, the contribution from the thio- or
selenoketenyl resonance structures is negligible. The averaged
Ti-S bond length is 0.14 Å shorter than the Ti-Se bond, which
reflects the difference in ionic radii of S2- (1.84 Å) and Se2-
(1.98 Å).14 The Ti-S-C angles of 109.0(2) and 112.5(2)° are
understandably greater than the Ti-Se-C angles of 107.2(2)
and 107.8(3)°.
Bis-alkynide complexes of late transition metals occasionally
undergo C-C bond-forming reactions.15 On the other hand, the
titanocene alkynides, Cp′2Ti(CtCR)2 were reported to react with
copper(I) salts to give Cp′2Ti(CtCR)2CuX (Cp′ ) cyclopen-
tadienyl derivatives; R ) Ph, SiMe3 etc., X ) halogens, SPh,
etc.).16 To examine reactivity of the Ti-bound alkynethiolates,
1
we carried out the reaction of 1 with /2 equiv of Ni(cod)2 in
toluene. The cod ligands were liberated during this reaction,
and a Ti2Ni cluster [Cp2Ti(µ-SCtCPh)2]2Ni (6) was isolated
as dark purple crystals in 33% yield.
Figure 1. Structure of MeCp2Ti(SCtCPh)2 (4).
1
The H NMR spectrum of 6 shows resonances attributable
to cyclopentadienyl and phenylethynethiolato fragments in
accord with the formulation. The ν(CtC) band appears at 2150
cm-1 in the IR spectrum, which is slightly higher than those of
1-4. The observed frequency is rather close to that found for
[(µ2-SCtCR)(µ2-SR′)Fe2(CO)6] (R ) Ph, n-C4H9, n-C5H11,
SiMe3; R′ ) Me, Et, PhCH2, CH2C(O)CH3, CH3C(O), (CH3)3-
CC(O)) (2164-2201 cm-1),10 in which the sulfur atom of
alkynethiolate bridges two iron centers. In light of the high Ct
C stretching frequency, alkynethiolates of 6 are anticipated to
bridge the metal atoms at sulfur. This geometrical feature was
confirmed by X-ray analysis, and the X-ray-derived molecular
structure is shown in Figure 3. Table 3 lists the selected bond
distances and angles.
Figure 2. Structure of Cp2Ti(SeCtCPh)2 (5).
Table 2. Selected Structural Parameters of Complexes 4 and 5
4
5
As shown in Figure 3, the cluster complex 6 consists of a
linear Ti-Ni-Ti spine, and four alkynethiolate ligands bridge
the metal atoms. Alternatively, the cluster can be viewed as a
Bond Distances (Å)
Ti-S1
2.448(2)
Ti-Se1
Ti-Se2
Se1-C1
Se2-C9
C1-C2
C9-C10
2.588(2)
2.563(2)
1.838(8)
1.857(9)
1.195(10)
1.17(1)
Ti-S2
2.427(2)
1.684(8)
1.687(7)
1.188(8)
1.178(8)
(13) Giolando, P. M.; Papavassiliou, M.; Pickardt, J.; Rauchfuss, T. B.;
Steudel, R. Inorg. Chem. 1988, 27, 2596.
(14) Shannon, R. D. Acta Crystallogr. 1976, A32, 751.
(15) (a) Hill, A. F.; Harris, M. C. J.; Melling, R. P. Polyhedron 1992, 11,
781. (b) Hills, A.; Hughes, D. L.; Jimenez-Tenorio, M.; Leigh, G. J.;
McGeary, C. A.; Rowly, A. T.; Bravo, M.; McKenna, C. E.; McKenna,
M.-C. J. Chem. Soc., Chem. Commun. 1991, 522.
(16) (a) Yasufuku, K.; Yamazaki, H. Bull. Chem. Soc. Jpn. 1972, 45, 2664.
(b) Lang, H.; Blau, S.; Nuber, B.; Zsolnai, L. Organometallics 1995,
14, 3216. (c) Lang, H.; Herres, M.; Zsolnai, M. Bull. Chem. Soc. Jpn.
1993, 66, 429. (d) Lang, H.; Imhof, W. Chem. Ber. 1992, 125, 1307.
(e) Lang, H.; Herres, M.; Imhof, W. J. Organomet. Chem. 1994, 465,
283. (f) Janssen, M. D.; Herres, M.; Zsolnai, M.; Spek, A. L.; Grove,
D. M.; Lang, H.; Koten, G. v. Inorg. Chem. 1996, 35, 2476. (g)
Janssen, M. D.; Ko¨hlaer, K.; Herres, M.; Dedieu, A.; Smeets, W. J.
J.; Spek, A. L.; Grove, D. M.; Lang, H.; Koten, G. v. J. Am. Chem.
Soc. 1996, 118, 4817. (h) Lang, H.; Weber, C. Organometallics 1995,
14, 4415. (i) Lang, H.; Frosh, W.; Wu, I. Y.; Blau, S.; Nuber, B. Inorg.
Chem. 1996, 35, 6266. (j) Lang, H.; Herres, M.; Zsolnai, L.; Imhof,
W. J. Organomet. Chem. 1991, 409, C7. (k) Herres, M.; Lang, H. J.
Organomet. Chem. 1994, 480, 235. (l) Berenguer, J. R.; Fornie´s, J.;
Lalinde, E.; Mart´ınez, F. Organometallics 1996, 15, 4537.
S1-C1
S2-C9
C1-C2
C9-C10
Bond Angles (deg)
S1-Ti-S2
Ti-S1-C1
Ti-S2-C9
S1-C1-C2
S2-C9-C10
95.79(8)
109.0(2)
112.5(2)
179.4(7)
174.8(7)
Se1-Ti-Se2
Ti-Se1-C1
Ti-Se2-C9
Se1-C1-C2
96.71(5)
107.2(2)
107.8(3)
176.7(8)
178.0(8)
Se2-C9-C10
Dihedral Angles (deg)
118.8
Ph(ring)-Ph(ring)
104.4
Ti(SPh)2 (99.3(1)°). It appears that alkynethiolate is sterically
less demanding than benzenethiolate.12 The Ti-Se bond dis-
(12) Muller, E. G.; Watkins, S. F.; Dahl, L. F. J. Organomet. Chem. 1976,
111, 73.

6778 Inorganic Chemistry, Vol. 37, No. 26, 1998
Sugiyama et al.
Figure 4. Structure of the anion part of[Li(tmeda)2][Cp*2Sm-
(SCtCPh)2] (7) (molecule 1).
Table 4. Selected Structural Parameters of 7
Figure 3. Structure of [Cp2Ti(µ-SCtCPh)2]2Ni (6).
molecule 1
molecule 2
Table 3. Selected Structural Parametrs of 6
Bond Distances (Å)
2.784(4) Sm2-S3
Sm1-S1
2.774 (4)
2.813(4)
1.63(1)
1.61(1)
1.18(1)
1.21(1)
Bond Distances (Å)
Sm1-S2
S1-C21
S2-C29
C21-C22
C29-C30
2.803(3)
1.61(1)
1.53(1)
1.20(1)
1.24(1)
Sm2-S4
S3-C57
S4-C65
C57-C58
C65-C66
Ni-Ti1
Ti1-S1
Ti1-S2
Ni-S1
Ni-S2
S1-C1
S2-C9
C1-C2
C9-C10
2.782(1)
2.510(2)
2.507(2)
2.225(2)
2.227 (2)
1.688(7)
1.691(7)
1.186(8)
1.193(8)
Ni-Ti2
Ti2-S3
Ti2-S4
Ni-S3
2.795(1)
2.521(2)
2.508(2)
2.209(2)
2.210(2)
1.683(6)
1.689(6)
1.183(7)
1.190(7)
Ni-S4
S3-C27
S4-C35
C27-C28
C35-C36
Bond Angles (deg)
114.25(7)
87.3(4)
97.7(4)
174.7(10)
179.3(10)
S1-Sm1-S2
Sm1-S1-C21
Sm1-S2-C29
S1-C21-C22
S2-C29-C30
S3-Sm2-S4
Sm2-S3-C57
Sm2-S4-C65
S3-C57-C58
S4-C65-C66
108.01(7)
94.0(4)
97.6(4)
175.9(10)
177(1)
Bond Angles (deg)
Ti1-Ni-Ti2
S1-Ti1-S2
S1-Ni-S2
Ti1-S1-Ni
Ti1-S2-Ni
Ti1-S1-C1
Ti1-S2-C9
Ni-S1-C1
Ni-S2-C9
S1-C1-C2
S2-C9-C10
179.71(5)
98.86(6)
117.75(6)
71.69(5)
71.69(5)
116.7(2)
116.8(2)
105.7(2)
104.6(2)
174.3(6)
173.5(6)
S3-Ti2-S4
S3-Ni-S4
97.64(6)
117.90(6)
72.11(5)
72.35(5).
117.6(2)
116.3(2)
108.5(2)
107.8(2)
175.2(6)
174.8(6)
from this Et2O solution was unsuccessful. However, addition
of TMEDA to the supernatant liquid produced a yellow
microcrystalline solid. Recrystallization of the solid from toluene
gave [Li(tmeda)2][Cp*2Sm(SCtCPh)2] (7) as orange crystals
in 42% yield. The 1H NMR signals of Cp* and phenyl protons
appeared as broad peaks due to paramagnetism associated with
f5 Sm(III). The ν(CtC) band, observed at 2133 cm-1 in the IR
spectrum, is shifted to lower compared with those of 1-4.
Ti2-S3-Ni
Ti2-S4-Ni
Ti2-S3-C27
Ti2-S4-C35
Ni-S3-C27
Ni-S4-C35
S3-C27-C28
S4-C35-C36
single Ni atom being sandwiched by the two titanocene bis-
alkynethiolate complexes 1. The core structure of 6 resembles
that of [Cp2Ti(µ-SMe)2]2Ni.17 In each titanocene fragment, two
alkynyl groups assume an anti conformation presumably to
avoid steric repulsion. Combining two such fragments, four
alkynyl groups around the Ti-Ni-Ti bond are staggered. In
the formation of 6, the Ni(0) oxidation state appears to be
retained, and the coordination geometry at Ni is approximately
tetrahedral. This zerovalent Ni center favors interactions with
the thiolate sulfurs, and coordination of the alkyne portion to
Ni does not take place. The relatively short Ni-Ti distances
(av 2.79 Å), coupled with the acute Ni-S-Ti angles (av 72.0°),
suggest a dative bond between d10 Ni and d0 Ti.18
We extended our study of alkynechalcogenolate complexes
of titanocene(IV) to lanthanides. The reaction of Cp*2Sm(µ-
Cl)2Li(OEt2)2 with 2 equiv of LiSCtCPh in THF at room-
temperature resulted in the formation of a yellow orange
solution. After removal of THF, the residue was extracted with
Et2O. Attempts to crystallize a Sm(III)-alkynethiolate complex
According to the X-ray analysis, the crystal of 7 consists of
discrete [Li(tmeda)2]+ cations and [Cp*2Sm(SCtCPh)2]- an-
ions, and no interactions between Li and SCtCPh can be seen.
Being crystallized in noncentrosymmetric P21 space group, an
asymmetric unit contains two crystallographically independent
cations and two anions. Although the geometric parameters are
somewhat different between the two complex anions, their main
structural features are practically the same. Therefore, Figure 4
shows the structure for only one of them, while the metric
parameters of the two complex anions are compared in Table
4.
The two alkynyl groups in the structure of 7 exhibit an anti
orientation, which contrasts to a syn orientation of 4 and 5. We
do not find particular electronic reasons for the different
orientations, and the choice of the two orientations is probably
determined by a crystal packing effect. The mean Sm-S
(17) Wark, T. A.; Stephan, D. W. Organometallics 1989, 8, 2836
(18) Braterman, P. S.; Wilson, V. A.; Joshi, K. K. J. Organomet. Chem.
1971, 31, 123.

Synthesis of Alkynechalcogenolato Complexes
Inorganic Chemistry, Vol. 37, No. 26, 1998 6779
distance of 2.79 Å is close to the longest end of the known
Sm(III)-S single bonds (2.65-2.83 Å).19 Interestingly, the Sm-
S-C angles vary substantially (87.3(4)°, 97.7(4)° for molecule
1 and 94.0(4), 97.6(4)° for molecule 2), and they are all smaller
than the Ti-S-C angles of 4 (109.0(2) and 112.5(2)°). The
long Sm-S distances indicate an ionic character of the bond,
which may lead to the flexible Ti-S-C angles.
Acknowledgment. Support from the JSPS Research Fel-
lowships for Young Scientists is gratefully acknowledged (H.S.).
(19) (a) Tatsumi, K.; Amemiya, T.; Kawaguchi, H.; Tani, K. J. Chem. Soc.,
Chem. Commun. 1993, 773. (b) Mashima, K.; Nakayama, Y.;
Fukumoto, H.; Kanehisa, N.; Kai, Y.; Nakamura, A. J. Chem. Soc.,
Chem. Commun. 1994, 1847. (c) Mashima, K.; Shibahara, T.;
Nakayama, Y.; Nakamura, A. J. Organomet. Chem. 1995, 501, 263.
(d) Cetinkaya, B.; Hitchcock, P. B.; Lappert, M. F.; Smith, R. G. J.
Chem. Soc., Chem. Commun. 1992, 932.
Supporting Information Available: X-ray crystallographic files,
in CIF format, for the structure determinations of 4, 5, 6, and 7 are
available on the Internet only. Access information is given on any
current masthead page.
IC980901X