Notes and references
(3 ml) was added catalyst (1 mol%) under N
2
atmosphere. The resulting
◦
mixture was kept at 60 C for the times reported in Table 1. Progress of
the reaction was monitored by TLC. After completion, the catalyst was
separated by filtration and washed with acetonitrile, dichloromethane
and dried under vacuum for further use. The filtrate was concentrated
under reduced pressure and the residue dissolved in dichloromethane
(10 ml). The organic layer was washed with water (2 ¥ 15 ml), dried over
‡
The melting points were determined in open-capillaries on a Buchi
1 13
apparatus and are uncorrected. The H and C NMR spectra were
recorded on a Bruker Avance 300 Spectrometer in CDCl with CHCl
7.27 ppm for H, 77 ppm for C) as a standard and the chemical
shifts are expressed in d parts per million relative to tetramethylsilane
TMS) as the internal standard. The IR spectra were recorded on
3
3
1
13
(
(
anhydrous MgSO and concentrated to yield the corresponding sulfone.
4
a Perkin-Elmer FT-IR X 1760 instrument. Elemental analyses were
done by using ASTM D-3828 (Kjeldhal method). Analyses of metal
content (for leaching experiments) were carried out by using inductively
coupled plasma atomic emission spectrometer (ICP-AES, PS-3000UV)
by Leeman Labs.
1 (a) A. D. Pomoga ˘i lo, Catalysis by Polymer-immobilized Metal
Complexes, CRC Press, New York, 1998; (b) N. E. Leadbeater and
M. Marco, Chem. Rev., 2002, 102, 3217–3274; (c) K. Burgess, Solid
Phase Organic Synthesis, John-Wiley, New York, 2000.
2 (a) K. Yao, M. Taniguchi, M. Nakata, M. Takahashi and A.
Yamagishi, Langmuir, 1998, 14, 2410; (b) A. R. Silva, M. M. A.
Freitas, C. Freire, B. de Castro and J. L. Figueiredo, Langmuir, 2002,
18, 8017; (c) P. Van Der Voort, M. Mathieu, E. F. Vansant, S. N. R.
Rao and M. G. White, J. Porous Mater., 1998, 5, 305; (d) M. Bartok,
G. Szollosi, A. Mastalir and I. Dekany, J. Mol. Catal. A: Chem.,
1999, 139, 227.
3 (a) T. Ray, S. F. Mapolie and J. Darkwa, J. Mol. Catal. A: Chem.,
2007, 267, 143; (b) T. Luts, W. Suprun, D. Hofmann, O. Klepel and
H. Papp, J. Mol. Catal. A: Chem., 2007, 261, 16; (c) M. R. Maurya,
U. Kumar and P. Manikandan, Dalton Trans., 2006, 3561–3575;
(d) A. Corma, C. Gonz a´ lez-Arellano, M. Iglesias, M. T. Navarro
and F. S a´ nchez, Chem. Commun., 2008, 6218; (e) C. Gonz a´ lez-
Arellano, A. Corma, M. Iglesias and F. S a´ nchez, Chem. Commun.,
2005, 1990; (f) A. Corma, E. Guti e´ rrez-Puebla, M. Iglesias, A.
Monge, S. P e´ rez-Ferreras and F. S a´ nchez, Adv. Synth. Catal., 2006,
348, 1899; (g) C. Gonz a´ lez-Arellano, A. Corma, M. Iglesias and F.
S a´ nchez, Adv. Synth. Catal., 2004, 346, 1758; (h) V. Ayala, A. Corma,
M. Iglesias and F. S a´ nchez, J. Mol. Catal. A: Chem., 2004, 221,
201.
Preparation of propargylated oxo–vanadium(IV) tridentate Schiff base 2:
Oxo–vanadium(IV) tridentate Schiff base 1 (2.3 g, 5.0 mmol) was added
2 3
in the stirred mixture of Na CO (40 mmol, 4.02 g) in DMF (30 mL).
Propargyl bromide (80 wt% in toluene, 12 mL, 10 mmol) was added
◦
dropwise slowly and the resulting mixture was heated at 80 C for 8 h.
The solvent was removed under reduced pressure and the residue was
dissolved in dichloromethane (30 ml). The organic layer was washed with
brine solution (20 mL ¥ 3) and water. The organic layer was dried over
anhydrous MgSO and concentrated under reduced pressure. The dark
4
-1
brown solid thus obtained was dried under vacuum for 5 h. IR (cm ):
283, 2953, 1659, 1590, 1544, 1232, 984. ESMS (M + CH COO ): 488.
3
-
3
Preparation of organo-functionalized mesoporous silica supports 3 and 5:
Mesoporous silica materials with a large pore size of 10 nm were synthe-
sized to accommodate the bulky Schiff base complexes using a triblock-
copolymer template EO20PO70EO20 (MW ca. 5800), tetraethylorthosili-
n
cate as silica source, and a hydrothermal synthesis method. Mesoporous
SBA-15 material functionalized with 3-azidopropylsilyl groups, 3,
was prepared by adding (3-azidopropyl)trimethoxysilane (4 mol%)
-1
during the synthesis of mesoporous silica materials (0.62 mmol g ).
Mesoporous silica functionalized with 3-chloropropylsilyl groups, 5, was
prepared by adding (3-chloropropyl)trimethoxysilane (4 mol%) during
the synthesis of mesoporous silica materials. The percentage of chloro-
functionalization in the prepared material 5 was determined by elemental
4 (a) C. W. Tornøe and M. Meldal, in American Peptide Symposium,
ed. M. Lebl and R. A. Houghten, American Peptide Society and
Kluwer Academic Publishers, San Diego, CA, 2001, p. 263; (b) V. V.
Rostovtsev, L. C. Green, V. V. Fokin and K. B. Sharpless, Angew.
Chem., Int. Ed., 2002, 41, 2596; (c) C. W. Tornøe, C. Christensen and
M. Meldal, J. Org. Chem., 2002, 67, 3057; (d) Q. Wang, T. R. Chan,
R. Hilgraf, V. V. Fokin, K. B. Sharpless and M. G. Finn, J. Am.
Chem. Soc., 2003, 125, 3192; (e) H. C. Kalb and K. B. Sharpless,
Drug Discovery Today, 2003, 8, 1128.
-1
analysis which was found to be 0.52 mmol g . During the synthesis of
mesoporous SBA-15 materials templates have been removed by soxhlet
extraction in ethanol for 24 h.
Immobilization of propargylated oxo–vanadium(IV) Schiff base 2 to
mesoporous silica 3 via click chemistry: To the solution of propargylated
oxo–vanadium(IV) Schiff base (0.53 g, 1.25 mmol) in dry DMF (25 ml)
-1
was added azido-functionalized mesoporous silica (0.62 mmol g , 2.0 g,
5 R. Huisgen, Pure Appl. Chem., 1989, 61, 613.
1
.24 mmol), CuI (5 mol%), Et
3
N (1.0 ml). The resulting suspension
6 (a) J. Nakazawa, T. Daniel and P. Stack, J. Am. Chem. Soc., 2008,
130, 14360; (b) A. Schlossbauer, D. Schaffert, J. Kecht, E. Wagner
and T. Bein, J. Am. Chem. Soc., 2008, 130, 12558.
◦
was vigorously stirred at 50 C for 24 h under nitrogen. The progress
was checked by IR as it showed the reduction of N band (2106 cm ).
3
After completion, the silica-supported catalyst 4 was filtered off and
washed thoroughly with acetonitrile, dried and then removed by soxhlet
extraction in acetonitrile for 8 h and dried under vacuum for 5 h,
-1
7 (a) A. R. McDonald, H. P. Dijkstra, B. M. J. M. Suijkerbuijk, G. P. M.
van Klink and G. van Koten, Organometallics, 2009, 28, 4689; (b) A.
Sch a¨ tz, M. Hager and O. Reiser, Adv. Funct. Mater., 2009, 19, 2109;
(c) A. R. McDonald, N. Franssen, G. P. M. van Klink and G. van
Koten, J. Organomet. Chem., 2009, 694, 2153; (d) J. Y. Ying, J. Lim,
S. S. Lee and S. N. B. Riduan, Int. Appl. No. PCT/SG2008/000088
(WO 2008/115 154); (e) G. Lv, W. Mai, R. Jin and L. Gao, Synlett,
2008, 1418; (f) A. Bastero, D. Font and M. A. Peric a` s, J. Org. Chem.,
2007, 72, 2460; (g) X.-Y. Wang, A. Kimyonok and M. Weck, Chem.
Commun., 2006, 3933; (h) S. Jain and O. Reiser, ChemSusChem, 2008,
1, 534; (i) M. Tilliet, S. Lundgren, C. Moberg and V. Levacher, Adv.
Synth. Catal., 2007, 349, 2079; (j) S. Jain, J. K. Joseph, F. E. Kuhn
and O. Reiser, Adv. Synth. Catal., 2009, 351, 230; (k) S. Jain and B.
Sain, Adv. Synth. Catal., 2008, 350, 1479.
-1
yield 2.20 g (84%). IR (cm ): 2994, 1661, 1441, 1391, 1083, 961,
02. TG weight loss to final oxide: found 1.7% (calculated 2.1%).
Nitrogen percentage (N %) determined by elemental analysis: found
.8% (calculated 3.5%).
Immobilization of oxo–vanadium(IV) Schiff base 1 to mesoporous silica
via direct method: To the stirred suspension of mesoporous silica 5
8
2
2
5
-1
(
0.52 mmol g , 2.0 g, 1.04 mmol) and NaH (0.12 g, 5 mmol) in dry
DMF (15 ml) was added dropwise a solution of oxo–vanadium Schiff
base 1 (1.21 g, 2.48 mmol) in dry DMF (10 ml) over the period of 15 min.
The resulting mixture was refluxed for 30 h under nitrogen atmosphere.
The resulting silica supported catalyst was separated via filtration and
washed thoroughly with acetonitrile, methanol, dried and then subjected
to soxhlet extraction in acetonitrile for 8 h and dried under vacuum for
8 R. Ando, T. Yagyu and M. Maeda, Inorg. Chim. Acta, 2004, 357,
2237.
5
7
h, yield 1.5 g (57%). IR (cm): 2962, 1657, 1498, 1439, 1419, 1088, 961,
98.
9 Starting from the 0.62 mmol N per g silica support, theoretical
3
-1
loading of vanadium Schiff base onto support is 0.42 mmol g .
10 Starting from 0.42 mmol g- loading of complex to the support,
calculated percentage of vanadium ions is 2.1%.
1
General experimental procedure for oxidation of sulfides: To the stirred
mixture of sulfide (1 mmol) and aq. 70% TBHP (2.5 mmol) in acetonitrile
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