Synthesis of titanium trichloride complexes of 1,2,3-trisubstituted cyclopentadienyls and their use in styrene polymerization

Article abstract of DOI:10.1016/S0022-328X(01)00749-5

The synthesis, characterization and styrene polymerization properties of titanium trichloride compounds (5, 1,3-dimethyl-2-n-butylcyclopentadienyl; 6, 1,3-dimethyl-2-t-butylcyclopentadienyl; 13, 1,3-diphenyl-2-n-butylcyclopentadienyl; 14, 1,3-dimethyl-2-phenylcyclopentadienyl; 15, 1,2,3-triphenylcyclopentadienyl) containing 1,2,3-trisubstituted cyclopentadienyl ligands are reported. Reactions of lithiated cyclopentadienide with Me₃SiCl followed by addition of TiCl₄ gave new titanium trichloride compounds 5 and 6, respectively, in reasonable yields, and reactions of cyclopentadiene with Ti(NMe₂)₄ followed by Me₃SiCl or Me₂SiCl₂ gave new titanium trichloride compounds 13-15, respectively, in reasonable yields. Compound 14 has been characterized by single crystal X-ray diffraction studies: monoclinic space group P2₁/c; a=15.893(2), b=7.199(1), c=12.812(2) ?, β=108.394(7)°, Z=4 and V=1390.9(3) ?³. The catalytic behavior of the new titanium compounds in styrene polymerization has been studied in the presence of excess methylaluminoxane.

Full text of DOI:10.1016/S0022-328X(01)00749-5

Journal of Organometallic Chemistry 627 (2001) 233–238
www.elsevier.nl/locate/jorganchem
Synthesis of titanium trichloride complexes of 1,2,3-trisubstituted
cyclopentadienyls and their use in styrene polymerization
Bun Yeoul Lee a,*1, Jin Wook Han b, Hwimin Seo b, In Su Lee b,
Young Keun Chung b,*2
a Department of Molecular Science and Technology, Ajou Uni6ersity, Suwon 442-749 South Korea
b School of Chemistry and Center for Molecular Catalysis, College of Natural Sciences, Seoul National Uni6ersity, Seoul 151-747, South Korea
Received 15 June 2000; received in revised form 26 February 2001; accepted 27 February 2001
Abstract
The synthesis, characterization and styrene polymerization properties of titanium trichloride compounds (5, 1,3-dimethyl-2-n-
butylcyclopentadienyl; 6, 1,3-dimethyl-2-t-butylcyclopentadienyl; 13, 1,3-diphenyl-2-n-butylcyclopentadienyl; 14, 1,3-dimethyl-2-
phenylcyclopentadienyl; 15, 1,2,3-triphenylcyclopentadienyl) containing 1,2,3-trisubstituted cyclopentadienyl ligands are reported.
Reactions of lithiated cyclopentadienide with Me3SiCl followed by addition of TiCl4 gave new titanium trichloride compounds 5
and 6, respectively, in reasonable yields, and reactions of cyclopentadiene with Ti(NMe2)4 followed by Me3SiCl or Me2SiCl2 gave
new titanium trichloride compounds 13–15, respectively, in reasonable yields. Compound 14 has been characterized by single
,
crystal X-ray diffraction studies: monoclinic space group P21/c; a=15.893(2), b=7.199(1), c=12.812(2) A, i=108.394(7)°,
3
,
Z=4 and V=1390.9(3) A . The catalytic behavior of the new titanium compounds in styrene polymerization has been studied
in the presence of excess methylaluminoxane. © 2001 Elsevier Science B.V. All rights reserved.
Keywords: Cyclopentadienyl; Titanium; Styrene; Polymerization; Syndiotactic
range by modification of the substituents on the cy-
clopentadienyl ring [19]. Thus, many research groups
are involved in the design of ligands to tailor the
catalytic activity and product properties. However, a
limited range of cyclopentadienyl titanium complexes
containing such ligands have been prepared and studied
due to the absence of a generalized synthetic method
for substituted cyclopentadiene. Recently, Takahashi et
al. [20] reported the synthesis of 1,2,3-trisubstituted
cyclopentadienes through the reaction of zirconacy-
clopentene with acid chloride in the presence of a
catalytic amount of copper chloride. Several years ago,
we reported [21] the general method for preparation of
1,2,3-trisubstituted cyclopentadienyls and their use in
the preparation of manganese tricarbonyl and zirco-
nium dichloride derivatives. The method can be easily
extended to synthesize 1,2,3-trisubstituted cyclopentadi-
enyl titanium trichlorides. Herein we report the synthe-
sis and characterization of 1,2,3-trisubstituted
cyclopentadienyl titanium trichloride and their behavior
in styrene polymerization.
1. Introduction
Since Ishihara et al. reported the first preparation of
syndiotactic polystyrene (s-PS) using the CpTiCl3/MAO
catalyst system [1,2], a wide variety of new catalytic
systems based on titanium or zirconium compounds
have been synthesized and studied as s-PS catalyst
[3–13]. Among those complexes, Cp*TiX3, (in-
denyl)TiCl3, and (substituted indenyl)TiCl3 derivatives
are the most active catalysts. Studies on the mechanism
involved in the polymerization of styrene have also
been reported [14–18].
The chemical and physical properties of cyclopenta-
dienyl titanium complexes can be varied over a wide
1 *Corresponding author. Tel.: +82-2-8806662; fax: +82-2-
8891598; e-mail: ykchung@plaza.snu.ac.kr
2 *Corresponding author. Tel.: +82-031-2191844; e-mail:
bunyeoul@madang.ajou.ac.kr
0022-328X/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(01)00749-5

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B.Y. Lee et al. / Journal of Organometallic Chemistry 627 (2001) 233–238
2. Experimental
2.1. General
(br s, 6 H), 1.30 (s, 9 H), −0.05 (s, 9 H) ppm.
13C-NMR (CDCl3) of 4: l 144.16, 142.65, 136.80,
128.10, 54.13, 34.84, 31.55, 18.96, 18.56, −1.88 ppm.
Red crystalline solids 6 were obtained from 4 in 80%
1
Reactions were carried out under argon or nitrogen
atmosphere using standard Schlenk techniques or in a
glove box. Methylaluminoxane (MAO) was purchased
from Akzo (6.4 wt.% of Al, MMAO type 4). Chloro-
trimethylsilane, dichlorodimethylsilane, and styrene
were purified by distillation over CaH2. Hexane and
toluene were purified over Na/K alloy under argon.
1H-NMR and 13C-NMR spectra were recorded on a
Bruker DPX-300 spectrometer. Elemental analyses were
done at the National Centre for Inter-University Re-
search Facilities, Seoul National University. Tm was
measured on a Thermal Analysis 3100. Gel permeation
chromatograms (GPC) were obtained at 140°C in
trichlorobenzene using Waters model 150-C+ GPC
and the data were analyzed using a polystyrene analyz-
ing curve. All trisubstituted cyclopentadienes 1, 2, and
7–9 were synthesized by the previously published pro-
cedures [21].
yield. H-NMR (CDCl3) of 6: l 6.55 (s, 2 H), 2.66 (s, 6
H), 1.46 (s, 9 H) ppm. 13C-NMR (CDCl3) of 6: l
149.05, 139.28, 126.63, 37.04, 30.90, 20.90 ppm. HRMS
m/e, M+, obsd. 301.9881, calc. 301.9875.
2.4. Synthesis of 13
To a solution of 7 (0.372 g, 1.36 mmol) in 10 ml of
toluene was added Ti(NMe2)4 (0.32 ml, 1.36 mmol). As
the reaction went on, the evolution of NHMe2 was
observed. The solution was stirred at 70°C for 4 h at
which time evolution of the gas ceased. All volatiles
were removed at reduced pressure to give a red oily
compound 10. As ClSiMe3 (5 ml) was added to 10 at
r.t., the solution changed to deep red. The resulting
solution was heated to 50°C for 18 h. After the solution
was cooled to r.t., the solution was evaporated to
dryness. Hexane (20 ml) was added to the residue and
the solution was filtered. The clear solution was kept in
a refrigerator (at −30°C). Reddish crystalline solids
were deposited. The isolated yield of 13 was 40% (0.23
2.2. Synthesis of 5
To a solution of 1 (0.78 g, 5.19 mmol) in 10 ml of
THF was added n-BuLi (5.19 mmol) at −78°C. The
solution was slowly warmed to room temperature (r.t.).
After the solution was stirred for 4 h at r.t., ClSiMe3
(0.70 ml) was added. After the solution was stirred
overnight, the solvent was removed at reduced pressure.
To the residue was added 30 ml of hexane. Filtration
and evaporation gave an oily compound 3.1H-NMR
(CDCl3): l 5.86 (br s, 1 H), 2.91 (br s, 1 H), 2.28–2.25
(m, 2 H), 1.96 (s, 6 H), 1.4–1.3 (m, 4 H), 0.92 (t, 6.7
Hz, 3 H), −0.05 (s, 9 H) ppm. 13C-NMR (CDCl3): l
141.49, 139.77, 137.49, 124.79, 51.35, 32.37, 25.50,
22.86, 14.87, 14.04, −2.00 ppm. Anal. Found: C,
75.10; H, 11.31. Calc. for C14H26Si: C, 75.59; H,
11.78%. To 3 (0.926 g, 4.17 mmol) was added 20 ml of
CH2Cl2. The solution was cooled to −78°C. TiCl4 was
added to the cold solution and the resulting solution
was warmed to r.t. After the solution was stirred for 4
h at r.t., all volatiles were removed at reduced pressure
1
g). H-NMR (CDCl3): l 7.7–7.3 (m, 10 H), 7.29 (s, 2
H), 3.31 (t, 7.5 Hz, 2 H), 1.1–0.9 (m, 4 H), 0.57 (t, 7.1
Hz, 3 H) ppm. 13C-NMR (CDCl3): l 141.68, 138.09,
133.79, 129.31, 129.04, 128.75, 122.95, 30.72, 27.77,
22.17, 13.34 ppm. Anal. Found: C, 59.16; H, 4.20. Calc.
for C21H21Cl3Ti: C, 58.98; H, 4.95%. HRMS m/e, M+
obsd. 426.0204, calc. 426.0188.
2.5. Synthesis of 14
To a solution of 8 (0.276 g, 1.62 mmol) in 5 ml of
toluene was added Ti(NMe2)4 (0.38 ml, 1.62 mmol).
The solution was heated at 50°C for 18 h. Removal of
1
all the volatiles gave 11. H-NMR (CDCl3): l 7.4–7.2
(m, 5 H), 5.84 (s, 2 H), 3.01 (s, 18 H), 2.15 (s, 6 H)
ppm. 13C-NMR (CDCl3): l 136.31, 130.60, 127.93,
125.73, 124.55, 121.99, 108.76, 48.78, 14.51 ppm. As
Cl2SiMe2 (10 ml) was added to 11 at r.t., the solution
changed to deep red. The resulting solution was heated
to 70°C for 3 h. All the volatiles were evaporated and
the residue was extracted with 40 ml of hot hexane. The
hexane solution was filtered and cooled to r.t. to precip-
itate the product. Red crystalline solids 14 were isolated
(0.388 g, 74%). Single crystals of 14 suitable for X-ray
study were grown in hexane at r.t. 1H-NMR (CDCl3): l
7.5–7.3 (m, 5 H), 6.57 (s, 2 H), 2.46 (s, 6 H) ppm.
13C-NMR (CDCl3): l 138.02, 136.88, 132.42, 130.25,
128.37, 128.31, 121.98, 16.46 ppm. Anal. Found: C,
48.27; H, 4.05. Calc. for C13H13Cl3Ti: C, 48.27; H,
3.81%.
1
to give yellowish red solids 5 (1.06 g, 77%). H-NMR
(CDCl3): l 6.71 (s, 2 H), 2.77 (t, 7.6 Hz, 2 H), 2.40 (s,
6 H), 1.5–1.3 (m, 4 H), 0.93 (t, 6.9 Hz, 3 H) ppm.
13C-NMR (CDCl3): l 141.19, 139.07, 123.74, 31.64,
28.17, 22.78, 16.20, 15.26, 13.84 ppm. HRMS m/e, M+,
obsd. 301.9884, calc. 301.9875.
2.3. Synthesis of 6
The same procedure as for the synthesis of 5 was
applied. The yield of 4 from 2 was 75%. 1H-NMR
(CDCl3) of 4: l 5.86 (br s, 1 H), 2.89 (br s, 1 H), 2.13

B.Y. Lee et al. / Journal of Organometallic Chemistry 627 (2001) 233–238
235
2.6. Synthesis of 15
cooled to r.t., solids were suspended. The solids were
filtered, washed with methanol, and dried at 100°C. The
polymer was extracted with refluxing 2-butanone for 12
h in order to determine the s-PS portion of the polymer
obtained.
The same procedure as for the synthesis of 14 was
1
applied. H-NMR (CDCl3) of 12: l 7.4–7.3 (m, 5 H),
7.1–7.0 (m, 9 H), 6.41 (s, 2 H), 3.03 (s, 18 H) ppm.
13C-NMR (CDCl3) of 12: l 137.21, 137.07, 132.51,
129.14, 128.32, 128.14, 128.00, 127.68, 126.98, 126.36,
124.74, 49.73 ppm. The yield of 15 from 12 was 50%.
Compound 15 was purified by recrystallization in tolu-
2.8. X-ray crystal structure determination of 14
All X-ray data were collected using a Siemens P4
diffractometer equipped with a Mo X-ray tube and a
graphite crystal monochromator. The orientation ma-
trix and unit cell parameters were determined by least-
squares analyses of the setting angles of 33 reflections in
the range 10.0°B2qB25.0°. Three check reflections
were measured every 100 reflections throughout data
collection and showed no significant variation in inten-
sity. Intensity data were corrected for Lorentz and
polarization effects. Decay corrections were also made.
The intensity data were corrected empirically with „-
scan data. All calculations were carried out with use of
the SHELX-97 programs. The unit cell parameters and
systematic absences, h0l (l=2n+1) and 0k0 (k=2n+
1), indicated unambiguously the P21/c space group.
The structure was solved by the direct method and
refined by full-matrix least-squares calculations, initially
with isotropic and finally anisotropic temperature fac-
tors for all non-hydrogen atoms. All hydrogen atoms
were located in the difference Fourier map and refined
isotropically. Crystal data, details of the data collection,
and refinement parameters are listed in Table 1.
1
ene at −30°C. H-NMR (CDCl3): l 7.4–7.2 (m, 6 H),
7.0–6.8 (m, 9 H), 6.75 (s, 2 H) ppm. 13C-NMR
(CDCl3): l 141.01, 135.86, 133.31, 132.72, 131.85,
129.81, 129.41, 128.58, 128.32, 122.42 ppm. Anal.
Found: C, 61.58; H, 3.83. Calc. for C23H17Cl3Ti: C,
61.72; H, 3.83%.
2.7. Polymerization
To a Schlenk flask was added successively toluene (40
ml), styrene (5.0 ml), and MAO (5.0 ml, 10 mmol of
Al). The solution was immersed into a preheated oil
bath (at 50, 75, and 100°C). After the solution was
stirred for 10 min, a catalyst (2.5 mmol in toluene
solution) was added with vigorous stirring. After 10
min, 50% HCl in methanol solution (20 ml) was care-
fully added via a syringe. As the reaction mixture was
Table 1
X-ray data collection and structure refinement for 14
Formula
C13H13Cl3Ti
Formula weight
Temperature (K)
Crystal system
Space group
323.48
294(2)
Monoclinic
P21/c
3. Results and discussion
Unit cell dimensions
3.1. Synthesis
,
a (A)
15.893(2)
7.199(1)
12.812(2)
108.394(7)
1390.9(3)
4
1.545
1.165
656
0.2993
0.3951
3.5–50
ꢀ
,
b (A)
,
c (A)
Compound 5 was prepared by treatment of pure
anhydrous TiCl4 with 3 in methylene dichloride, a well
known and routine technique (Eq. (1)) [3,5–11,19d,22].
i (°)
3
,
V (A )
Z
dcalc (g cm−3
)
v (mm−1
F(000)
Tmin
)
(1)
Tmax
2q range (°)
Scan type
Scan speed
Reflections measured
Unique reflections
Variable
2572
2449
Compound 3 was obtained by reaction of 1 with
n-BuLi and chlorotrimethylsilane. The overall yield
from 1 to 5 was 77%. In the same way, 6 was synthe-
sized with overall yield of 75%. Treatment of cyclopen-
tadienes bearing phenyl group(s) with TiCl4 yielded
untraceable black precipitates that might be due to the
reduction of TiCl4 to TiCl3. The phenyl group may help
the electron transfer from the cyclopentadiene to tita-
nium tetrachloride. Thus, the synthetic method de-
Reflections with I\2|(I)
2086
207
0.361
−0.301
1.027
Parameters refined
−3
,
Maximum, in Dz (e A
)
−3
,
Miniimum, in Dz (e A
)
GOF on F2
R
wR2
0.0345
0.0897
a
a wR2=ꢀ[w(Fo2−Fc2)2]/ꢀ[w(Fo2)2]1/2
.

236
B.Y. Lee et al. / Journal of Organometallic Chemistry 627 (2001) 233–238
Fig. 1. Molecular structure of compound 14, with the atom-labeling scheme.
bond distances and angles for the coordination geome-
try of the titanium atom are given in Table 2.
The coordination polyhedron about the Ti atom is a
distorted tetrahedron formed by three Cl atoms and
one Cp ring. The Ti–Cp-ring centroid bond distance is
scribed above seems to be confined to the synthesis of
titanium chloride complexes of alkyl substituted
cyclopentadienyls.
Titanium chloride compounds 13–15 having
a
phenyl group(s) were synthesized by the method shown
in Eq. (2).
(2)
,
2.029 A. The phenyl ring (C8–C13) is tilted with re-
Treatment of cyclopentadienes 7–9 with Ti(NMe2)4
resulted in the formation of amido complexes 10–12
[23]. Complexes 10–12 could be transformed to the
corresponding trichloride complexes via reaction with
appropriate chlorinating reagents. However, there was
no general method to chlorinate all the amido com-
plexes. Treatment of 10 with chlorotrimethylsilane at
ambient temperature in toluene gave a product having
two chloride groups. When chlorination of 10 was
carried out in neat chlorotrimethylsilane at 50°C, the
desired trichloride complex 13 was obtained. Com-
pounds 14 and 15 were obtained when dichloro-
dimethylsilane was used as a chlorinating reagent.
spect to the cyclopentadienyl ring with a dihedral angle
of 44.49(8)°. The Ti–Cp-ring carbon distances indicate
that the Ti–Cp-ring interaction is asymmetric. The
,
distances are in the range 2.310–2.403 A. For other
(h5-RC5H4)TiCl3, the Ti–Cp-ring carbon distance is
longest for the carbon atom bonded to the substituent
group [8,24]. In 14, C1 and C5 form longer distances
with the Ti atom than the other Cp-ring carbon atoms.
The reason why C5 forms a longer distance with the Ti
atom is due to the tilt of the phenyl group toward C5.
The Ti–Cl bond distances are in the typical range at
,
Ti–C=2.230 A (average).
3.2. X-ray analysis
3.3. Polymerization
Single crystals of 14 suitable for X-ray crystal struc-
ture determination were grown in hexane at room
temperature. Fig. 1 gives an ORTEP view of the struc-
ture of 14 together with the atom labeling. Selected
Compounds 5, 6, and 13–15 were tested for the
polymerization of styrene with MAO as a cocatalyst.
For comparison, Cp*TiCl3 was also used as a polymer-
ization catalyst under identical conditions. The results

B.Y. Lee et al. / Journal of Organometallic Chemistry 627 (2001) 233–238
237
are shown in Table 3. The trisubstituted cyclopentadi-
enyl titanium compounds showed higher activities than
Cp*TiCl3. The highest activity was obtained with 14 at
75°C. At 50°C, molecular weights (Mw) of the polymers
obtained with 5, 6 and Cp*TiCl3 were 54 000–68 000 at
50°C but those for 13, 14 and 15 bearing phenyl
substituents were 79 000, 40 000 and 25 000, respec-
tively. The phenyl substituents on the cyclopentadienyl
ligand in 13 increased the activity as seen in indenyl
titanium trichloride complexes [8,11]. Titanium com-
pounds having a phenyl group(s) on the cyclopentadi-
enyl ring also showed higher activities than those
having only alkyl groups on the cyclopentadienyl ring.
Rausch et al. [11] explained the enhanced activities of
phenyl-substituted indenyl complexes as the increased
resonance stabilization. However, complexes 13, 14 and
15 showed quite different activities. The decreased ac-
tivity for 15 was presumably due to the steric problem
as in (indenyl)TiCl3 derivatives [11]. Complex 15 was
completely inactive at 100°C.
As the reaction temperature increased, the syndiotac-
tic yields, measured by extraction with refluxing 2-bu-
tanone, decreased for all compounds. Up to 75°C, the
syndiotactic yields remained above 90% except for 15
which showed low syndiotactic yield (76%) at 75°C. At
100°C, the syndiotactic yields for 6, 14 and Cp*TiCl3
dropped to 73–77%, but those for 5 and 13 were still
88–90%.
Molecular weights decreased as the reaction tempera-
ture increased. Narrow molecular weight distributions
(Mw/Mn, 1.7–2.2) imply that the polymers were pre-
pared by single-site catalysts. The values and trends of
Table 2
,
Selected bond distances (A) and bond angles (°) in 14
Ti–Cl3
Ti–C3
Ti–C1
C1–C5
C2–C6
C5–C7
2.2237(8)
2.310(3)
2.401(2)
1.429(3)
1.500(4)
1.493(4)
Ti–Cl1
Ti–C4
Ti–C5
C1–C8
C3–C4
Ti–Cp(1) a
2.2258(8)
2.316(3)
2.403(3)
1.480(4)
1.393(4)
2.029
Ti–Cl2
Ti–C2
C1–C2
C2–C3
C4–C5
2.2415(8)
2.364(2)
1.428(4)
1.409(4)
1.415(4)
Cl3–Ti–Cl1
Cl1–Ti–Cl2
C2–C1–C8
C3–C2–C1
C1–C2–C6
C3–C4–C5
C4–C5–C7
C9–C8–C1
101.40(3)
101.75(3)
126.5(2)
107.4(2)
128.1(3)
109.2(2)
125.4(3)
121.2(2)
Cl3–Ti–Cl2
C2–C1–C5
C5–C1–C8
C3–C2–C6
C4–C3–C2
C4–C5–C1
C1–C5–C7
103.45(3)
107.9(2)
125.5(2)
124.5(3)
108.7(3)
106.7(2)
127.7(3)
a Cp(1) refers to the computed centroid of the ring carbons C1–C5.
Table 3
Polymerization of styrene
Catalyst
Tp (°C)
Yield (g)
Activity a
Tm (°C)
Mw
Mw/Mn
SY (%) b
5
5
5
6
6
6
13
13
13
14
14
14
15
15
15
50
75
100
50
75
100
50
75
100
50
75
100
50
0.33
1.17
1.22
0.59
0.87
0.94
0.89
1.22
1.22
1.25
1.63
1.50
0.75
0.72
0
0.79
2.8
2.9
1.4
2.1
2.3
2.1
2.9
2.9
3.0
3.9
3.6
1.8
1.7
0
272
264
253
272
265
249
271
269
255
269
262
242
267
255
60,000
31,000
11,000
54,000
21,000
7,500
79,000
37,000
14,000
40,000
20,000
8,200
1.9
2.2
1.8
2.0
2.0
1.7
1.9
2.1
1.9
2.4
2.0
1.7
2.2
1.7
93
89
88
99
96
73
95
90
90
96
92
75
94
76
25,000
10,000
75
100
50
75
100
Cp*TiCl3
Cp*TiCl3
Cp*TiCl3
0.038
0.28
0.44
0.091
0.67
1.1
272
272
269
68,000
43,000
18,000
2.0
2.2
2.0
91
77
a 106g/(mol(Ti)×h).
b SY (% of syndiotacticity)=(g of 2-butanone-insoluble PS)/(g of PS)×100.

238
B.Y. Lee et al. / Journal of Organometallic Chemistry 627 (2001) 233–238
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Crystallographic data for structural analysis have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC No. 158012 for compound 14.
Copies of this information may be obtained free of
charge from The Director, CCDC, 12 Union Road,
Cambridge, CB2 1EZ, UK (Fax: +44-1223-336033;
e-mail: deposit@ccdc.cam.ac.uk or www: http://
www.ccdc.cam.ac.uk).
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This work was supported by the Korea Science and
Engineering Foundation (KOSEF) (1999-1-122-001-5)
and the KOSEF through the Center for Molecular
Catalysis. J.W.H. and H.S. thank the Ministry of Edu-
cation for the Brain Korea 21 Fellowship.
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