W.-H. Leung et al.
(%) for C34H70Co2O27P6S2Ti2·CH2Cl2: C 28.0H, 4.83; found: C 27.8, H
4.75.
Ti2O2(m-SO4) core acts as a tridentate, dianionic ligand that
binds to Ru in a fac-O,O,O(SO4) fashion. Whether such a
binding mode may play a role in bifunctional M/sulfated zir-
conia catalysts is not clear. In addition, we found that the
triflato complexes 4 and 14 are Lewis acidic and capable of
catalyzing organic reactions such as the Diels–Alder reac-
tion. Thus, it may be possible to model zirconia-based acid-
catalyzed reactions using oxygen-rich LOEt–Ti and LOEt–Zr
complexes. Currently, efforts are being made to investigate
the interactions between transition metal alkyls and hy-
drides and LOEt–Ti and LOEt–Zr sulfato compounds, which
may provide insight into mechanisms of organometallic re-
actions occurring on sulfated zironia surfaces.
[LOEtTi(OTf)3] (4): To a solution of 2 (40 mg, 0.03 mmol) in CH2Cl2
(10 mL) at ꢀ408C was added triflic acid (0.05 mL) under nitrogen. The
reaction mixture was slowly warmed to room temperature at which it
was stirred for 2 h. To the resulting orange solution was added Et2O/
hexane (1:1) until an orange precipitate was formed. The solid was col-
lected and recrystallized from CH2Cl2–Et2O–hexane under nitrogen to
give orange crystals that were suitable for X-ray diffraction. Yield: 31 mg
(48%). 1H NMR (300 MHz, CDCl3, 258C, TMS): d=1.39 (t, J(H,H)=
7 Hz, 18H; CH3), 4.33–4.43 (m, 12H; CH2), 5.34 ppm (s, 5H; Cp); 19F
{1H} NMR (282.5 MHz, CDCl3, 258C, CF3C6H5): d=ꢀ77.7 ppm (s);31P
{1H} NMR (121.5 MHz, CDCl3, 258C, H3PO4): d=134.0 ppm (s); elemen-
tal analysis calcd (%) for C20H35CoF9O18P3S3Ti: C 23.3, H 3.39; found: C
23.4, H 3.49.
[(LOEt)3Ti3(m-O)3(m3-SO4){Ag(OTf)}][OTf] (5): To a solution of 2 (76 mg,
0.06 mmol) in CH2Cl2 (10 mL) was added AgOTf (60 mg, 0.23 mmol),
and the mixture was stirred at room temperature for 2 h. The volatiles
were removed in vacuo and the residue was extracted into toluene. Re-
crystallization from THF–hexane afforded pale yellow crystals that were
suitable for X-ray diffraction. Yield: 27 mg (30%). 1H NMR (300 MHz,
CDCl3, 258C, TMS): d=1.31 (t, J(H,H)=7 Hz, 54H; CH3), 3.90–4.04 (m,
6H; CH2), 4.05–4.20 (m; 24H, CH2), 4.21–4.38 (m, 6H; CH2), 5.10 ppm
(s, 15H; Cp); 19F {1H} NMR (282.5 MHz, CDCl3, 258C, CF3C6H5): d=
ꢀ78.2 ppm (s); 31P {1H} NMR (121.5 MHz, CDCl3, 258C, H3PO4): d=
120.9 (d, J(P,P)=1.2 Hz), 129.2 ppm (t, J(P,P)=1.2 Hz); MS (FAB): m/z:
2044 [MꢀAgOTf]+, 1894 [MꢀAgOTfꢀOTf]+; IR (KBr): n˜ =1263 cmꢀ1
(S=O); elemental analysis calcd (%) for C53H105AgCo3F6O40P9S3Ti3: C
27.6, H 4.60; found: C 27.8, H 4.75.
Experimental Section
General procedures: Unless otherwise stated, all reactions were carried
out in air. NMR spectra were recorded on a Bruker ALX 300 spectrome-
1
ter operating at 300, 75, 282.5, and 121.5 MHz for H, 13C, 19F, and 31P, re-
spectively. Chemical shifts (d, ppm) were reported with reference to
SiMe4 (1H and 13C), CF3C6H5 (19F), and 85% H3PO4 (31P). Infrared spec-
tra (KBr) were recorded on a Perkin-Elmer 16 PC FT-IR spectrophotom-
eter and mass spectra on a Finnigan TSQ 7000 (FAB) and Applied Bio-
system QSTAR (ESI) spectrometer. Elemental analyses were performed
[(LOEtTi)4(m-O)6]·1.5HNO3
(6·1.5HNO3):
Ba(NO3)2
(11.4 mg,
by Medac Ltd, Surrey, UK.
[38]
0.044 mmol) in water (4 mL) was added dropwise to an aqueous solution
(30 mL) of 2 (30 mg, 0.022 mmol), and the mixture was stirred in air at
room temperature for 30 min. The solution was filtered, extracted into
CH2Cl2, and evaporated to dryness. Recrystallization from CH2Cl2–hex-
anes gave yellow crystals. Yield: 13 mg (25%). 1H NMR (300 MHz,
CDCl3, 258C, TMS): d 1.28 (t, J(H,H)=9 Hz), 72H; CH3), 3.93–4.23 (m,
48H; OCH2), 5.08 ppm (s, 20H; Cp); 31P {1H} NMR (121.5 MHz, CDCl3,
The ligand NaLOEt
,
[{Rh(cod)Cl}2],[39] [Ru(tBu2bpy)(PPh3)2Cl2],[30] and
[LOEtZrF3][21] were prepared according to literature methods. Titanyl sul-
fate (~15 wt% in dilute sulfuric acid) and zirconyl nitrate (~35 wt% in
dilute nitric acid) were obtained from Aldrich and used as received. A
stocksolution of titanyl sulfate in sulfuric acid ([Ti] ~0.13m) was freshly
prepared by diluting commercial titanyl sulfate (Aldrich; 1 mL) with dis-
tilled water (9 mL) and used for the following preparations.
258C, TMS):
C68H140Co4O42P12Ti4·1.5HNO3·2H2O: C 31.0, H 5.88, N 0.80; found: C
30.78, H 5.58, N 0.77; MS (ESI): m/z: 1214.966 [M + 1]2+
[(LOEtTi)2(O)2(SO4){Rh(cod)}2][OTf]2 (7): mixture of 2 (30 mg,
d 122.5 ppm (s); elemental analysis calcd (%) for
[(LOEtTi)2(m-O)2(m-SO4)] (2): To the stocksolution of titanyl sulfate
(1.0 mL, 0.095 mmol) were added water (7 mL) and NaLOEt (48 mg,
0.086 mmol) in water (3 mL). The mixture was stirred at room tempera-
ture for 10 min and Na2SO4 (60 mg, 0.423 mmol) in water (1 mL) was
added. The resulting solution was stirred for 2 h, extracted with CH2Cl2
(210 mL), and dried with anhydrous Na2SO4. The solvent was removed
in vacuo and the residue was recrystallized from acetone–hexane to
afford yellow crystals that were suitable for X-ray analysis. Yield: 56 mg
(50%). 1H NMR (300 MHz, [D6]acetone, 258C, TMS): d=1.43 (t,
J(H,H)=7 Hz, 36H; CH3), 4.28 (m, 24H; OCH2), 5.30 ppm (s, 10H;
Cp); 31P {1H} NMR (121.5 MHz, [D6]acetone, 258C, H3PO4): d=
119.3 ppm (m); 31P {1H} NMR (121.5 MHz, CDCl3, 258C, H3PO4): d=
119.0 ppm (m); 31P {1H} NMR (121.5 MHz, D2O, pD ~0.5, 258C, H3PO4):
d=123.2 (d, J(P,P)=1.3 Hz), 131.1 ppm (t, J(P,P)=1.2 Hz); IR (KBr):
n˜ =1259 cmꢀ1 (S=O); MS (FAB): m/z: 1294 [M]+; elemental analysis
calcd (%) for C34H70Co2O24P6STi2: C 31.5, H 5.45; found: C 31.5, H 5.41.
.
A
0.022 mmol), [{Rh(cod)Cl}2] (9.8 mg, 0.010 mmol), and AgOTf (10.2 mg,
0.020 mmol) in CH2Cl2 (5 mL) was stirred for at room temperature under
nitrogen for 4 h and filtered. The orange filtrate was layered with hexane
overnight to give orange needles. Yield: 15 mg (75%). 1H NMR
(300 MHz, CDCl3, 258C, TMS): d=1.22 (m, 8H; cod), 1.35 (m, 36H;
CH3), 1.64 (d, J(H,H)=7.8 Hz, 4H; cod), 2.36 (m, 4H; cod), 4.01 (m,
8H; cod), 4.19 (m, 24H; CH2), 5.24 ppm (s, 10H; Cp); 19F {1H} NMR
(282.5 MHz, CDCl3, 258C, CF3C6H5): d=ꢀ78.5 ppm (s); 31P {1H} NMR
(121.5 MHz, CDCl3, 258C, H3PO4): d=122.0 pm (m); IR (KBr): n˜ =1275,
1265 cmꢀ1 (S=O); elemental analysis calcd (%) for C52H94Co2-
F6O30P6Rh2S3Ti2: C 31.0, H 4.70; found: C 30.9, H 5.21.
[(LOEtTi)2(O)2(SO4){Re(CO)3][OTf] (8): To solution of [Re(CO)5Cl]
(59 mg, 0.16 mmol) in CH2Cl2 (5 mL) was added AgOTf (46.6 mg,
0.18 mmol) under nitrogen, and the mixture was stirred for 2 h and fil-
tered. To the filtrate was added 2 (109 mg, 0.08 mmol) and resulting so-
lution was stirred at room temperature under nitrogen for three days.
The volatiles were pumped off and the residue was extracted into Et2O.
Recrystallization from Et2O–hexane afforded yellowish orange needles.
Yield: 89.0 mg (63%). 1H NMR (300 MHz, CDCl3, 258C, TMS): d=1.34
(t, 18H; CH3), 4.27 (m, 12H; CH2), 5.25 ppm (s, 5H; Cp); 19F {1H} NMR
(282.5 MHz, CDCl3, 258C, CF3C6H5): d=ꢀ79.4 ppm (s); 31P {1H} NMR
(121.5 MHz, CDCl3, 258C, H3PO4): d=119.4 (br. s), 125.6 (br. s),
128.2 ppm (d); IR (KBr): n˜ =2025 cmꢀ1 (C=O), 1278, 1294 cmꢀ1 (S=O);
MS (FAB): m/z: 1566 [MꢀOTf + 1]+.
[(LOEt)2Ti2(m-SO4)2(m-O)] (3): To the titanyl sulfate stocksolution
(0.64 mL, 0.06 mmol) were added 10% H2SO4 (10 mL) and NaLOEt
(30 mg, 0.054 mmol) in water (3 mL). The mixture was stirred for 5 min
and concentrated H2SO4 (0.48 g) was added. The resulting solution was
stirred for 2 h, extracted with CH2Cl2 (210 mL), and dried over anhy-
drous Na2SO4. The solvent was removed in vacuo. Recrystallization from
THF–hexane afforded yellow crystals, which were suitable for X-ray
analysis. Yield: 36 mg (48%). 1H NMR (300 MHz, [D6]acetone, 258C,
TMS): d=1.50 (t, J(H,H)=7 Hz, 36H; CH3), 4.28–4.44 (m, 24H; OCH2),
5.38 ppm (s, 10H; Cp); 31P {1H} NMR (121.5 MHz, [D6]acetone, 258C,
H3PO4): d=120.6 (t, J(P,P)=1.3 Hz), 125.9 ppm (d, J(P,P)=1.3 Hz); 31P
{1H} NMR (121.5 MHz, CDCl3, 258C, H3PO4): d=119.4 (t, J(P,P)=
1.1 Hz), 125.8 ppm (d, J(P,P)=1.1 Hz); 31P {1H} NMR (121.5 MHz, D2O,
pD ~0.5, 258C, H3PO4): d=124.5 (t, J(P,P)=1 Hz), 131.5 ppm (d,
J(P,P)=1 Hz); IR (KBr): n˜ =1281 cmꢀ1 (S=O); elemental analysis calcd
[{(LOEt)2Ti2(m-O)}(m3-SO4)(m-O)2{Ru(tBu2bpy)(PPh3)}][OTf]2 (9): A mix-
ture of [Ru(tBu2bpy)(PPh3)2Cl2] (29.3 mg, 0.04 mmol) and AgOTf
(40.0 mg, 0.16 mmol) in CH2Cl2 (20 mL) was stirred at room temperature
108
ꢀ 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2005, 11, 101 – 111