Lithium, titanium and vanadium dithiocarboxylates

Article abstract of DOI:10.1039/b210691d

Reaction of the in situ generated lithium aryls 2,6-Mes₂C₆H₃Li and 2,6-Trip₂C₆H₃Li (Mes = 2,4,6-trimethylphenyl, Trip = 2,4,6-triisopropylphenyl) with CS₂ afforded the lithium di

Full text of DOI:10.1039/b210691d

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Lithium, titanium and vanadium dithiocarboxylates†
Christina Ives, Elaine L. Fillis and John R. Hagadorn*
Department of Chemistry and Biochemistry, University of Colorado Boulder, CO 80309-0215,
USA
Received 30th October 2002, Accepted 6th January 2003
First published as an Advance Article on the web 17th January 2003
Reaction of the in situ generated lithium aryls 2,6-Mes2C6H3Li and 2,6-Trip2C6H3Li (Mes = 2,4,6-trimethylphenyl,
Trip = 2,4,6-triisopropylphenyl) with CS2 afforded the lithium dithiocarboxylates [2,6-Mes2C6H3CS2]Li and [2,6-
Trip2C6H3CS2]Li in good yields. These sterically-hindered S-donor ligands proved useful for the salt-metathesis
preparation of the paramagnetic Ti() and V() derivatives [2,6-Mes2C6H3CS2]TiCl2(thf )2 and [2,6-Trip2C6H3-
CS2]2VCl(L)2 (L = thf, py). Similarly, reaction of [2,6-Trip2C6H3CS2]Li with TiCl4(thf )2 in the presence of py afforded
the diamagnetic Ti() [2,6-Trip2C6H3CS2]2TiCl2(py). Single-crystal X-ray diffraction studies are reported for [2,6-
Mes2C6H3]Li(OEt2)2, [2,6-Mes2C6H3CS2]TiCl2(thf )2, [2,6-Trip2C6H3CS2]2TiCl2(py), and [2,6-Trip2C6H3CS2]2VCl(py)2.
Introduction
Coordination complexes supported by sulfur-donor ligands
have attracted significant interest due to their interesting elec-
tronic and structural properties.1 These complexes have also
frequently been studied in the context of biomimetic chemistry,
as metalloproteins featuring metal centers supported by natur-
ally-occurring S-donors perform diverse roles in biology (e.g.
catalysis, electron transfer, metal sequestration).2 We have
begun exploring extremely sterically-hindered S-donor ligands
in the hope that they will allow us to access reactive low-
coordination number transition-metal derivatives. In this initial
report, we describe two new dithiocarboxylate ligands, based on
a versatile terphenyl backbone,3 and their use in the synthesis of
mononuclear titanium and vanadium derivatives.
Results and discussion
Lithium salts of the bulky dithiocarboxylate anions [2,6-
Mes2C6H3CS2]Ϫ and [2,6-Trip2C6H3CS2]Ϫ (Mes = 2,4,6-Me3C6-
Fig. 1 Molecular structure of [2,6-Mes2C6H3]Li(OEt2)2 drawn with
50% thermal ellipsoids. All hydrogens and the minor components of the
H2, Trip = 2,4,6-iPr3C6H2) were prepared by the reaction of CS2
disordered Et2O molecules are omitted.
with the corresponding aryllithium4 species (Scheme 1). The
2.467(6) and 2.480(6) Å, respectively (Table 1). The C–S bonds
also reflect this binding mode, with essentially identical dis-
tances of 1.68 Å. Snaith and coworkers have reported the only
other structurally characterized lithium dithiocarboxylates.5
For comparison, the structure of [(2-MeC4H2N2)CH2CS2]-
Li(tmeda) (tmeda = N,N,NЈ,NЈ-tetramethylethylenediamine)
features an asymmetrically chelating dithiocarboxylate anion
with much longer Li–S distances of 2.554(4) and 2.688(5) Å.
Also of interest, a series of heavy alkali metal (K–Cs) dithio-
carboxylates has been reported to adopt bimetallic structures
featuring µ-dithiocarboxylate anions.6 Structures of related
Li dithiocarbamate7 and trithiocarbonate8 have also been
reported.
The Li dithiocarboxylates have proven to be useful reagents
Scheme 1 Ar = 2,6-Mes2C6H3, 2,6-Trip2C6H3; L = py, thf. Reagents
for the preparation of a range of transition-metal derivatives.
Reaction of [2,6-Mes2C6H3CS2]Li(Et2O)2 with 1 equiv TiCl3-
(thf )3 immediately forms a teal solution. The mononuclear
Ti() species [2,6-Mes2C6H3CS2]TiCl2(thf )2 was isolated in
36% yield from Et2O solution. Solution magnetic susceptibility
measurements gave a µeff = 1.6(1) µB, which is consistent with a
d1 metal center. The solid-state structure is shown in Fig. 2. The
pseudo-octahedral Ti is ligated to a symmetrically chelating
dithiocarboxylate, with the pair of chloride ligands being trans
to the S-donors. The remaining two coordination sites are
occupied by a pair of thf molecules. The small S–Ti–S bite
angle of 68.26(3)Њ results in the relatively large Cl–Ti–Cl angle
of 111.23(4)Њ. The Ti–S distances of 2.554(1) and 2.552(1) are
and conditions: (i) CS2, Et2O–hexanes, Ϫ70 ЊC; (ii) TiCl3(thf )3, toluene,
rt; (iii) TiCl4(thf )2, toluene, py, rt; (iv) VCl3(thf )3, toluene, L, rt.
yellow to orange products were isolated in moderate (ca. 55%)
yields as simple Lewis base adducts, and their compositions
were determined by a combination of NMR spectroscopy and
combustion analysis. A single-crystal X-ray diffraction study of
[2,6-Mes2C6H3CS2]Li(OEt2)2 was also performed. As shown in
Fig. 1, the dithiocarboxylate anion binds to a single Li-center as
a symmetric chelate, with Li1–S1 and Li1–S2 distances of
† Electronic supplementary information (ESI) available: additional crys-
tallographic details. See http://www.rsc.org/suppdata/dt/b2/b210691d/
T h i s j o u r n a l i s © T h e R o y a l S o c i e t y o f C h e m i s t r y 2 0 0 3
D a l t o n T r a n s . , 2 0 0 3 , 5 2 7 – 5 3 1
527

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Table 1 Selected bond lengths (Å) and angles (Њ) for structurally
characterized compounds
[2,6-Mes2C6H3]Li(OEt2)2
Li1–S1
Li1–S2
Li1–O1
Li1–O2
S1–C1
S2–C1
2.467(6)
2.480(6)
1.919(9)
1.905(9)
1.684(3)
1.676(3)
S1–Li1–S2
S1–Li1–O1
S1–Li1–O2
S2–Li1–O1
S2–Li1–O2
O1–Li1–O2
73.77(15)
119.8(3)
112.2(3)
114.5(3)
120.1(4)
111.9(3)
[2,6-Mes2C6H3]TiCl2(thf )2
Ti1–S1
Ti1–S2
Ti1–Cl1
Ti1–Cl2
Ti1–O1
T1–O2
S1–C1
S2–C1
S1–Ti1–S2
S1–Ti1–Cl1
S1–Ti1–Cl2
S1–Ti1–O1
2.552(1)
S1–Ti1–O2
S2–Ti1–Cl1
S2–Ti1–Cl2
S2–Ti1–O1
S2–Ti1–O2
Cl1–Ti1–Cl2
Cl1–Ti1–O1
Cl1–Ti1–O2
Cl2–Ti1–O1
Cl2–Ti1–O2
O1–Ti1–O2
91.65(6)
157.87(3)
90.91(3)
91.88(6)
92.23(6)
111.23(4)
88.64(6)
87.89(6)
88.63(7)
87.89(6)
174.66(7)
2.554(1)
2.325(1)
2.331(1)
2.085(2)
2.089(2)
1.679(3)
1.691(1)
68.26(3)
89.61(4)
159.14(3)
93.05(6)
Fig. 2 Molecular structure of [2,6-Mes2C6H3]TiCl2(thf )2 drawn with
50% thermal ellipsoids. All hydrogens are omitted.
[2,6-Trip2C6H3]2TiCl2(py)
Ti1–S1
Ti1–S2
Ti1–S3
Ti1–S4
Ti1–Cl1
Ti1–Cl2
Ti1–N1
S1–Ti1–S2
S1–Ti1–S3
S1–Ti1–S4
S1–Ti1–Cl1
S1–Ti1–Cl2
S1–Ti1–N1
S2–Ti1–S3
2.5624(8)
S2–Ti1–S4
S2–Ti1–Cl1
S2–Ti1–Cl2
S2–Ti1–N1
S3–Ti1–S4
S3–Ti1–Cl1
S3–Ti1–Cl2
S3–Ti1–N1
S4–Ti1–Cl1
S4–Ti1–Cl2
S4–Ti1–N1
Cl1–Ti1–Cl2
Cl1–Ti1–N1
Cl2–Ti1–N1
139.85(3)
93.17(3)
88.03(3)
143.77(6)
67.68(2)
87.79(3)
93.77(3)
143.44(6)
92.05(3)
87.83(3)
76.07(6)
178.27(3)
88.93(7)
89.36(7)
2.5302(8)
2.5190(8)
2.5484(8)
2.3045(8)
2.2867(9)
2.277(2)
67.30(2)
139.36(3)
152.78(3)
87.05(3)
92.26(3)
76.71(6)
72.79(2)
[2,6-Trip2C6H3]2VCl(py)2
V1–S1
V1–S2
V1–S3
V1–S4
V1–Cl1
V1–N1
V1–N2
S1–V1–S2
S1–V1–S3
S1–V1–S4
S1–V1–Cl1
S1–V1–N1
S1–V1–N2
S2–V1–S3
2.5425(9)
S2–V1–S4
S2–V1–Cl1
S2–V1–N1
S2–V1–N2
S3–V1–S4
S3–V1–Cl1
S3–V1–N1
S3–V1–N2
S4–V1–Cl1
S4–V1–N1
S4–V1–N2
Cl1–V1–N1
Cl1–V1–N2
N1–V1–N2
156.22(3)
79.21(3)
90.95(6)
86.76(6)
67.10(3)
141.24(3)
101.37(6)
82.49(7)
77.64(3)
83.65(6)
97.17(7)
89.83(6)
86.58(7)
176.05(9)
2.5498(8)
2.5489(9)
2.5380(9)
2.4056(8)
2.154(2)
2.167(2)
67.07(3)
Fig. 3 Molecular structure of [2,6-Trip2C6H3]2TiCl2(py) drawn with
50% thermal ellipsoids. All hydrogens and the minor components of the
disordered iPr-groups are omitted.
73.65(3)
134.37(3)
145.06(3)
82.12(7)
99.92(7)
136.64(3)
dithiocarboxylates in [2,6-Trip2C6H3CS2]2TiCl2(py) is asym-
metric. The Ti bonds to S(1) and S(4) (ave 2.555 Å) are about
0.03 Å longer than those to S(2) and S(3). This is explained as a
small trans influence arising from the weaker donor properties
of py relative to the S-donors.
identical, and are comparable to the average Ti–S distances
reported for the Ti() species Ti(S2CNEt2)4 (2.564 Å),9
CpTi(S2CMe)3 (2.603 Å),10 and CpTi(S2CNMe2)3 (2.611 Å).11
Although [2,6-Mes2C6H3CS2]TiCl2(thf )2 would be expected to
have relatively long Ti–S bonds as a result of its larger ionic
radius, its lower coordination number relative to the afore-
mentioned Ti() complexes offsets this effect.
Reaction of two equiv [2,6-Trip2C6H3CS2]Li(thf )3 with VCl3-
(thf )3 in toluene solution formed a dark burgundy solution.
Following work up in hexanes–HMDSO (hexamethyl-
disiloxane), [2,6-Trip2C6H3CS2]2VCl(thf )2 was isolated in 28%
yield as small burgundy crystals. The low isolated yield for this
reaction appears to be due to the extreme solubility of the
product in hydrocarbon solvents. A slightly higher yield was
achieved for the less soluble py adduct [2,6-Trip2C6H3CS2]2-
VCl(py)2. Combustion analysis data were consistent with the
formulations, and IR spectroscopy revealed the presence of py
(νpy = 1604, 1580, 1566 cmϪ1) in [2,6-Trip2C6H3CS2]2VCl(py)2.
Both complexes are paramagnetic with ambient temper-
ature solution magnetic moments (2.8–2.9 µB) consistent with
d2 electronic configurations. The solid-state structure determin-
ation of [2,6-Trip2C6H3CS2]2VCl(py)2 confirmed the assignment
of the product. As shown in Fig. 4, the V center approximates
a pentagonal bipyramidal geometry, with the two py ligands
occupying the axial positions. The V–S bond lengths are all
The Ti() [2,6-Trip2C6H3CS2]2TiCl2(py) was prepared by the
reaction of 2 equiv [2,6-Trip2C6H3CS2]Li(thf )3 with TiCl4(thf )2
in the presence of excess py. The diamagnetic product was
1
isolated in good yield as red crystals from Et2O solution. H
NMR spectroscopic data indicated a symmetric or fluxional
environment, and integration data and combustion analysis
revealed a 2 : 1 ratio of dithiocarboxylate to py. The solid-state
structure features a 7-coordinate Ti center in an approximate
pentagonal bipyramidal environment (Fig. 3). The equatorial
ligands include a pair of chelating dithiocarboxylates and the
py. The trans chlorides occupy the axial positions. In contrast to
the aforementioned Li and Ti() complexes, the binding of the
D a l t o n T r a n s . , 2 0 0 3 , 5 2 7 – 5 3 1
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dark solution was allowed to warm to ambient temperature
over several hours. After stirring overnight, the resulting red
solution was concentrated slightly and cooled to Ϫ40 ЊC. The
product was isolated as orange crystals, which were washed
with hexanes (2 × 60 mL) and dried under reduced pressure
(9.0 g, 52%). 1H NMR (2% CD3CN in CDCl3): δ 7.14 (t, J = 7.6
Hz, 1H, p-C6H3), 6.83 (d, J = 7.6 Hz, 2H, m-C6H3), 6.72 (s, 4H,
m-Mes), 3.38 (q, J = 7.0 Hz, 9H, Et2O), 2.18 (s, 6H, p-Mes), 2.12
(s, 12H, o-Mes), 1.10 (t, J = 7.0 Hz, 12H, Et2O). 13C{1H} NMR
(2% CD3CN in CDCl3): δ 152.6, 138.8, 137.4, 135.3, 135.1,
128.6, 127.1, 125.8, 116.4, 65.7, 21.5, 21.0, 15.0. IR: 1461 (vs),
1446 (s), 1376 (s), 1216 (m), 1018 (s), 908 (m), 854 (m), 751 (m),
741 (m), 722 (w) cmϪ1. Anal. Calcd (found) for C33H45O2S2Li:
C, 72.75 (72.52); H, 8.33 (8.34%).
[2,6-Trip2C6H3CS2]Li(py)3. Hexanes (75 mL) and Et2O
(25mL) were added to 2,6-Trip2C6H3I (5.94 g, 9.75 mmol)
to give a clear colorless solution. The solution was cooled to
Ϫ70 ЊC and BuLi (5.70 mL, 9.75 mmol) was added dropwise to
form a cloudy white solution. The mixture was warmed to room
temperature and stirred for 0.5 h. After cooling to Ϫ70 ЊC, CS2
(0.600 mL, 9.75 mmol) was added dropwise to give a cloudy
pink solution. The reaction was warmed slowly to room tem-
perature resulting in a brown solution. The volatile materials
were removed under reduced pressure to afford a mustard
yellow solid which was extracted into Et2O (150 mL) and fil-
tered. Pyridine (2 mL) was added, and the solution was concen-
trated to saturation. Cooling to Ϫ40 C yielded the product as a
Fig. 4 Molecular structure of [2,6-Trip2C6H3]2VCl(py)2 drawn with
50% thermal ellipsoids. All hydrogens and the minor component of a
disordered iPr-group are omitted.
very similar with an average value of 2.545 Å. To our
knowledge, there are no other structurally characterized V()
dithiocarboxylates or dithiocarbamates. The only other such V
dithiocarboxylates are the pseudo-dodechaderal V(SCPh)4 and
V(SCH2Ph)4 which feature average V–S distances of 2.49 and
2.50 Å, respectively.12
In summary, we have reported a pair of new sterically-
hindered dithiocarboxylate ligands. These have proven to be
useful for the preparation of a range of early transition metal
derivatives by salt-metathesis methodology. As a result of the
bulky 2,6-diaryl-substituted ligands, these Ti and V complexes
feature only one or two dithiocarboxylates per metal. This is a
feature not commonly observed in early-metal dithiocarboxyl-
ate or dithiocarbamate coordination chemistry.
1
yellow solid (5.0 g, 64%). H NMR (CDCl3): δ 8.48 (m, 6H,
α-py), 7.72 (m, 3H, γ-py), 7.28 (m, 6H, β-py), 7.2–7.1 (m, 3H,
m,p-C6H3), 7.00 (s, 4H, m-Trip), 3.09 (sept, J = 6.7 Hz, 4H,
m-CHMe2), 2.96 (sept, J = 6.7 Hz, 2H, p-CHMe2), 1.30 (d,
J = 7.0 Hz, 12H, p-CHMe2), 1.20 (d, J = 6.8 Hz, 12H,
o-CH(Me)Me), 1.06 (d, J = 6.8 Hz, 12H, o-CH(Me)Me).
13C{1H} NMR (CDCl3): δ 152.9, 150.0, 148.0, 146.9, 137.2,
137.1, 134.0, 130.1, 124.4, 123.7, 119.9, 34.4, 31.1, 26.4, 24.5,
23.2. IR: 3040 (w), 2954 (s), 2924 (s), 1594 (m), 1485 (w), 1461
(s), 1440 (s), 1377 (m), 1360 (w), 1067 (w), 1035 (w), 1021 (m),
1004 (w), 759 (w), 750 (w), 721 (w), 701 (m), 624 (w) cmϪ1.
Anal. Calcd (found) for C52H64N3S2Li: C, 77.86 (77.16); H, 8.04
(7.95); N, 5.24 (5.20%).
Experimental
General considerations
[2,6-Trip2C6H3CS2]Li(thf )3. This compound was prepared
analogously to [2,6-Trip2C6H3CS2]Li(py)3 except that thf was
used in place of pyridine (65% yield). 1H NMR (CDCl3): δ 7.10
(t, J = 6.7 Hz, 1H, p-C6H3), 7.04 (d, J = 6.6 Hz, 2H,m-C6H3),
6.89 (s, 4H, m-Trip), 3.50 (m, 12H, thf), 2.96 (br m, 4H,
m-CHMe2), 2.81 (br m, 2H, p-CHMe2), 1.68 (m, 12H, thf), 1.19
(m, 24H), 1.00 (d, J = 6.8 Hz, 12H). 13C{1H} NMR (CDCl3):
δ 147.7, 146.8, 136.5, 133.5, 129.9, 123.5, 120.8, 119.8, 68.2,
34.1, 30.9, 26.2, 25.5, 24.2, 23.0. IR: 3038 (w), 2952 (s), 2925 (s),
2917 (s), 2871 (s), 2854 (s), 2727 (w), 2671 (w), 1461 (s), 1377 (s),
1316 (w), 1302 (w), 1261 (w), 1169 (w), 1070 (w), 1045 (m), 1019
(m), 940 (w), 913 (w), 892 (w), 871 (w), 803 (w), 759 (w), 722 (w)
cmϪ1.
Standard techniques for air-sensitive chemical manipulations
were used unless stated otherwise.13 2,6-Mes2C6H3I (Mes =
2,4,6-Me3C6H2),14 2,6-Trip2C6H3I (Trip = 2,4,6-iPr3C6H2),15
TiCl3(thf )3, TiCl4(thf )4, and VCl3(thf )3 were prepared following
literature procedures.16 Hexanes, Et2O, toluene, tetrahydrofuran
(thf ), and CH2Cl2 were passed through columns of activated
alumina and sparged with N2 prior to use. Hexamethyl-
disiloxane (HMDSO) and pyridine (py) were distilled from Na
under N2. BuLi was purchased from commercial sources and
used as received. CDCl3 was vacuum transferred from CaH2.
1
Chemical shifts (δ) for H-NMR spectra are given relative to
residual protium in the deuterated solvent at δ 7.24 for CDCl3.
13C{1H}-NMR spectra are given relative to 13CDCl3 at δ 77.00.
Infrared spectra were taken as mineral oil mulls between KBr
plates unless stated otherwise. Elemental analyses were deter-
mined by Desert Analytics. Solution magnetic moments were
[2,6-Trip2C6H3CS2]2VCl(thf )2. Toluene (20 mL) was added to
[2,6-Trip2C6H3CS2]Li(thf )3 (2.00 g, 2.56 mmol) and VCl3(thf )3
(0.433 g, 1.28 mmol) to form a dark burgundy solution. After
stirring overnight, the volatile materials were removed under
reduced pressure to give a dark residue which was extracted
into hexanes (50 mL). The burgundy solution was filtered and
concentrated to 20 mL. The addition of an equal volume of
HMDSO resulted in the formation of fine burgundy crystals of
product (0.49 g, 28%). 1H NMR (CDCl3): δ (ω1/2, Hz) 18.6 (45),
17.0 (50), 6.72 (400), 4.73 (125), 2.94 (100), 2.84 (115), 2.18
(105), 1.59 (650), 1.18 (280), 1.05 (300), 0.92 (50), 0.74 (300).
IR: 2952 (s), 2928 (s), 2922 (s), 2854 (s), 1462 (s), 1378 (s),
1365 (m), 1315 (w), 1305 (w), 1225 (w), 996 (w), 932 (w), 873
(w), 806 (w), 764 (w), 722 (w) cmϪ1. Anal. Calcd (found) for
1
determined at ambient temperature by H NMR spectroscopy
using Evans’ method.17
Syntheses
[2,6-Mes2C6H3CS2]Li(Et2O)2. Hexanes (150 mL) and Et2O
(75 mL) were added to 2,6-Mes2C6H3I (15.6 g, 35.3 mmol) to
form a colorless suspension. At Ϫ20 ЊC, a hexanes solution of
BuLi (20.4 mL, 35.3 mmol) was added dropwise over 30 min
and the suspension was stirred for an additional 30 min. At
Ϫ70 ЊC, CS2 (2.34 mL, 38.8 mmol) was added dropwise, and the
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Table 2 Crystallographic data and collection parameters
Compound
[2,6-Mes2C6H3CS2]-
Li(Et2O)2
C33H45LiO2S2
544.75
Monoclinic
P21/n (no. 14)
Ϫ89
11.5924(13)
11.5958(12)
24.140(3)
3239.8(6)
90
93.241(2)
90
[2,6-Mes2C6H3CS2]-
TiCl2(thf )2
C37H51Cl2O3S2Ti
726.70
Monoclinic
P21/c (no. 14)
Ϫ140
14.553(6)
15.809(6)
16.514(5)
3711(2)
[2,6-Trip2C6H3CS2]2TiCl2(py)ؒ
Et2O
C83H113Cl2NOS4Ti
1387.78
[2,6-Trip2C6H3CS2]2VCl(py)2ؒ
2py
Formula
M
Crystal system
Space group
T /ЊC
a/Å
b/Å
c/Å
V/Å3
α/Њ
C94H118ClN4S4V
1518.55
Monoclinic
P21/c (no. 14)
Ϫ138
22.648(2)
13.572(1)
29.404(3)
8718(2)
90
Triclinic
¯
P1 (no. 2)
Ϫ138
12.7871(7)
16.9214(9)
20.390(1)
3988.6(4)
80.002(1)
78.030(1)
68.350(1)
2
90
102.35(4)
90
β/Њ
γ/Њ
105.288(2)
90
4
Z
4
4
µ (mmϪ1
)
0.190
0.521
0.322
0.286
Reflections collected
Unique reflections
Data/restraints/
parameters
26733
6640
6640/2/334
36233
9861
9861/0/406
56179
24742
18248/4/780
85590
28159
17808/0/850
R1, wR2 (for I>2σI)
R1, wR2 (all data)
GOF
0.0684, 0.1793
0.1013, 0.2027
1.043
0.0562, 0.1376
0.0900, 0.1561
1.028
0.0619, 0.1628
0.0827, 0.1722
1.054
0.0554, 0.1300
0.1042, 0.1456
0.979
Largest peak, hole/e ÅϪ3
0.712, Ϫ0.478
0.448, Ϫ0.742
0.823, Ϫ0.490
0.539, Ϫ0.541
C82H114S4VClO2: C, 73.15 (72.00); H, 8.53 (8.25%). µeff(CDCl3)
= 2.9(1) µB.
and filtered. Concentration and cooling to Ϫ40 ЊC afforded the
product as green-blue crystals (1.07 g, 36%). IR: 2952 (s), 2855
(s), 1461 (m), 1377 (s), 1015 (s), 1002 (s), 926 (w), 856 (m), 730
(m) cmϪ1. Anal. Calcd (found) for C37H51Cl2O2S2Ti: C, 62.53
(62.49); H, 7.23 (7.00%). µeff(C6D6) = 1.6(1) µB.
[2,6-Trip2C6H3CS2]2VCl(py)2. Toluene (20 mL) was added to
[2,6-Trip2C6H3CS2]Li(py)3 (0.383 g, 0.477 mmol) and VCl3(thf )3
(0.0807 g, 0.239 mmol) to give a dark red solution. The solution
was stirred overnight at room temperature. The volatile
materials were removed under reduced pressure to give a dark
residue which was extracted into hexanes (50 mL) and filtered.
The red-green filtrate was concentrated and cooled to Ϫ40 ЊC.
The product was isolated as dark purple crystals (0.12 g, 35%).
1H NMR (CDCl3): δ (ω1/2, Hz) 16.6 (60), 15.5 (400), 13.6 (150),
8.60 (40), 8.00 (70), 7.65 (40), 6.92 (300), 2.06 (140), 1.35 (85),
0.63 (100). IR: 3077 (m), 3051 (m), 3041 (m), 2953 (s), 2924 (s),
2859 (s), 1604 (m, py), 1580 (w, py), 1566 (w, py), 1485 (w), 1461
(s), 1445 (s), 1379 (s), 1360 (m), 1316 (w), 1237 (w), 1217 (w),
1102 (w), 1068 (w), 1044 (w), 1030 (w), 1019 (m), 1009 (m), 939
(m), 877 (m), 804 (w), 778 (w), 755 (m), 743 (w), 722 (w), 701
(m), 694 (m), 690 (m), 690 (m), 651 (w) cmϪ1. Anal. Calcd
(found) for C84H108S4VClN2: C, 74.16 (73.68); H, 8.00 (7.62); N,
2.06 (2.17%). µeff(CDCl3) = 2.8(1) µB.
X-Ray crystallography
Table 2 lists a summary of crystal data and collection param-
eters for all crystallographically characterized compounds.
Single-crystal structure determinations were performed within
the Department of Chemistry and Biochemistry at the
University of Colorado.
General procedure. Crystals were examined under a light
hydrocarbon oil (Paratone-N) and mounted with silicone
vacuum grease onto a thin glass fiber affixed to a tapered
copper mounting-pin. This assembly was transferred to the
goniometer of a Siemens SMART CCD diffractometer
equipped with a locally modified LT-2A low-temperature
apparatus. Cell parameters were determined using reflections
harvested from 3 orthogonal sets of 20 0.3Њ Ω scans. A mini-
mum of a hemisphere of data was collected using 0.3Њ Ω scans
in two correlated exposures. All data were corrected for Lorentz
and polarization effects, and a semi-empirical absorption cor-
rection was applied using SADABS.18 Structure solutions and
refinements were performed (SHELXTL-Plus V5.0) on F 2.18
CCDC reference numbers 196425–196428.
[2,6-Trip2C6H3CS2]2TiCl2(py). Toluene (75 mL) was added to
[2,6-Trip2C6H3CS2]Li(thf )3 (1.73 g, 2.21 mmol) and TiCl4(thf )2
(0.370 g, 1.11 mmol) to form a red solution. After a few
minutes, pyridine (0.40 mL, 4.9 mmol) was added. After stirring
overnight, the volatiles were removed under reduced pressure to
afford a red solid. The solid was extracted with Et2O (80 mL)
and filtered through Celite. Concentration to 10 mL and cool-
ing to Ϫ40 ЊC afforded the product as red crystals (1.11 g,
76.1%). 1H NMR (CDCl3): δ 8.80 (d, J = 5.2 Hz, 2H, α-Py), 7.78
(t, 7.5 Hz, 1H, γ-Py), 7.34–7.27 (m, 4H, β-Py ϩ p-C6H3), 7.19
(d, J = 7.5 Hz, 4H, m-C6H3), 6.80 (s, 8H, m-Trip), 2.78 (sept,
J = 6.8 Hz, 4H, p-CHMe2-Trip), 2.54 (sept, J = 6.8 Hz, 8H,
o-CHMe2-Trip), 1.19 (d, J = 6.7 Hz, 24H), 1.06 (d, J = 6.7 Hz,
24H), 0.96 (d, J = 6.7 Hz, 24H). 13C{1H} NMR (CDCl3):
δ 152.3, 148.0, 146.5, 146.3, 139.0, 136.4, 133.8, 129.9, 127.8,
124.7, 120.1, 34.3, 31.0, 26.1, 24.2, 22.1. Anal. Calcd (found) for
[2,6-Trip2C6H3CS2]2TiCl2(py)ؒ0.5Et2O: C81H108Cl2NO0.5S4Ti: C,
71.40 (72.02); H, 7.75 (8.06); N, 0.99 (1.04%).
See http://www.rsc.org/suppdata/dt/b2/b210691d/ for crystal-
lographic data in CIF or other electronic format.
Acknowledgements
We thank Dr Bruce C. Noll for for the structural determin-
ations of [2,6-Mes2C6H3CS2]Li(Et2O)2 and [2,6-Mes2C6H3CS2]2-
TiCl2(thf )2 and the University of Colorado for funding.
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