ACTIVATION OF SUPPORTED OLEFIN METATHESIS CATALYSTS BY ORGANIC REDUCTANTS

Abstract

An organic reductant, in particular an organo silicon reductant suitable for activating supported catalysts of the type MO.sub.nE.sub.m, wherein E is S and/or Se, in particular MO.sub.n, wherein M is W, Mo or Re, is described as well as its use in metathesis reactions. The reduced catalysts are able to metathesize olefins at low temperatures and are therefore also suitable for metathesis of functionalized olefins.

Claims

1. A method for producing an activated supported catalyst, said method comprising contacting a supported catalyst of the type MO.sub.nE.sub.m with E being S and/or Se, in particular MO.sub.D, with at least one organic reductant, said reductant comprising at least one double bond or at least one silyl group of the type SiX.sub.2Y in such proximity to one or more further double bond(s) that upon oxidation an aromatic structure is formed , wherein in the silyl group of the type SiX.sub.2Y each X is independently selected from H, R′, halogen, OR, NR.sub.2, wherein each R′ is independently selected from unsubstituted or substituted, linear or branched or cyclic C1 to C18 alkyl, unsubstituted or substituted linear or branched or cyclic C1 to C18 alkenyl, unsubstituted or substituted linear or branched or cyclic C1 to C18 alkynyl, or an unsubstituted or substituted aromatic group each R is independently selected from H, R′, silyl of type —SiX.sub.2Y the Y of each silyl group can be the same or different and is selected from the group as defined for X or two Y together are —O— or a single bond in an oxygen-free and dry environment.

2. The method of claim 1, wherein the reductant is a reductant of formula (I) ##STR00009## wherein E.sup.1 is selected from C—R.sup.5, N, P, As, or B n is 0 or 1 R.sup.1 to R.sup.4 and R.sup.5 are the same or different and are selected from the group comprising —H, —R′, silyl of type —SiX.sub.2Y, —OR, —NR.sub.2, halogens, —NO.sub.2, phosphates, carbonates and sulfates, wherein in all the groups each R′ is independently selected from the group comprising unsubstituted or substituted, linear or branched or cyclic C1 to C18 alkyl, unsubstituted or substituted linear or branched or cyclic C1 to C18 alkenyl, unsubstituted or substituted linear or branched or cyclic C1 to C18 alkynyl or an unsubstituted or substituted aromatic group, in particular optionally aryl substituted C1 to C6 alkyl, such as methyl or butyl or benzyl or methylbenzyl, optionally alkyl like methyl substituted cyclohexyl, optionally alkyl like methyl substituted phenyl, e.g. tolyl, each R is independently selected from the group comprising H, R′, silyl of type SiX.sub.2Y, or R.sup.1 and R.sup.2 together form a —(E.sup.2).sub.l— chain that together with the C.sup.1 and C.sup.2 to which they are bound form a 4- to 12-membered ring, wherein l is 2 to 10 and/or R.sup.3 and R.sup.4 together form a —(E.sup.2).sub.m— chain that together with the C.sup.2 and E.sup.1 to which they are bound form a 4- to 12-membered ring, wherein m is 1 to 9 and wherein each E.sup.2 is independently selected from the group comprising E.sup.1R.sup.6, or O, or two adjacent E.sup.2 are —CR.sup.7═CR.sup.8—, preferably in vinylic or allylic position with regard to one or more SiX.sub.2Y group(s), wherein E.sup.1 is as defined above R.sup.6, R.sup.7 and R.sup.8 are as defined for R.sup.5 or SiX.sub.2Y each X is independently selected from the group comprising H, R′, halogen, OR, NR.sub.2, wherein R′ and R are as defined above each Y is as defined above for X or two Y together are —O— or a single bond, wherein said —X.sub.2Si——SiX.sub.2— groups can be on adjacent E.sup.1 and E.sup.2 and/or on two adjacent E.sup.2 and/or on adjacent E.sup.1 and C1 and/or on adjacent E.sup.2 and C.sup.2, and/or on C.sup.1 and C.sup.2, and/or on E.sup.1 and E.sup.2 spaced further apart and/or on E.sup.1 and C.sup.2 and/or on E.sup.2 and C.sup.1 spaced further apart and/or on E.sup.2 and C.sup.2 spaced further apart and /or on two E2 spaced further apart.

3. The method of claim 2, wherein at least one of the variables in formula (I) and much preferred all variables are selected from the following groups: E.sup.1 is selected from C—R.sup.5 and N n is 1 R.sup.1 to R.sup.4 and R.sup.5 are the same or different and are selected from the group comprising —H, —R′, silyl of type —SiX.sub.3, wherein in all the groups each R′ is independently selected from the group comprising unsubstituted or substituted, linear or branched or cyclic C1 to C6 alkyl, unsubstituted or substituted linear or branched or cyclic C1 to C6 alkenyl, unsubstituted or substituted linear or branched or cyclic C1 to C6 alkynyl or an unsubstituted or substituted up to 6 membered aromatic group, each R is independently selected from the group comprising H, R′, silyl of type —SiX.sub.3, or R.sup.1 and R.sup.2 together form a —(E.sup.2).sub.l— chain that together with the C.sup.1 and C.sup.2 to which they are bound form a 6-membered ring, wherein l is 4 and/or R.sup.3 and R.sup.4 together form a —(E.sup.2).sub.m— chain that together with the C.sup.2 and E.sup.1 to which they are bound form a 5 to 8-membered ring, wherein m is 2 to 5 and wherein each E.sup.2 is independently selected from the group comprising E.sup.1R.sup.6, or two adjacent E.sup.2 are —R.sup.7═CR.sup.8—, preferably in vinylic or allylic position with regard to one or more SiX.sub.3 group(s), wherein E.sup.1 is as defined above R.sup.6, R.sup.7 and R.sup.8 are as defined for R.sup.5 or SiX.sub.3 each X is independently selected from the group comprising H and R′, wherein R′ is as defined above.

4. The method of any one of claims 1 to 3, wherein at least one reductant is selected from compounds of one of formulas (II) to (VII) ##STR00010##

5. The use of any one of claims 1 to 4, wherein at least one reductant is a compound of formula (H), preferably at least one of ##STR00011##

6. The method of any one of claims 1 to 5, wherein the reduction reaction is performed without a solvent or with a solvent, said solvent being an aprotic solvent and/or at a temperature in the range of −20° C. to 500° C., preferably 40° C. to 250° C., more preferred at about 70° C.

7. The method of any one of claims Ito 6, wherein the supported catalyst is of type MO.sub.nE.sub.m, in particular of the type MO.sub.n, wherein M is selected from the group consisting of W, Mo, Re and combinations thereof, and wherein the support is a metal oxide, in particular a metal oxide selected from silica, alumina, ceria, titania, zirconia, niobia, thoria or mixed oxides such as Al.sub.2O.sub.3—SiO.sub.2, in particular silica.

8. Use of an organic reductant as defined in any one of claims 1 to 5 for activating a supported catalyst of the type MO.sub.nE.sub.m, in particular of the type MO.sub.n, wherein M is selected from the group consisting of W, Mo, Re or combinations, such as a supported WO.sub.3 or MoO.sub.3 or Re.sub.2O.sub.7.

9. The use of claim 8, wherein the support is selected from the group consisting of silica, alumina, ceria, titania, niobia, zirconia, thoria or mixed oxides such as Al.sub.2O.sub.3—SiO.sub.2, in particular silica.

10. A supported catalyst obtainable by the method of any one of claims 1 to 7.

11. A supported catalyst which is an at least partially reduced MO.sub.n catalyst with the formula (VIII), ##STR00012## wherein Q is the valence of the metal which may be a mixed valence due to differently reduced metal centers l is 1 to 4, n is 0 to 2, l+m+2n=Q and each X is independently selected from H, R′, halogen, OR, NR.sub.2, wherein each R′ is independently selected from unsubstituted or substituted, linear or branched or cyclic C1 to C18 alkyl, unsubstituted or substituted linear or branched or cyclic C1 to C18 alkenyl, unsubstituted or substituted linear or branched or cyclic C1 to C18 alkynyl, or an unsubstituted or substituted aromatic group, in particular optionally aryl substituted C1 to C6 alkyl such as methyl or butyl or benzyl or methylbenzyl, optionally alkyl like methyl substituted cyclohexyl, optionally alkyl like methyl substituted phenyl, such as tolyl, and each R is independently selected from the group consisting of H, R′ and silyl of the type —SiX.sub.2Y, wherein R′ is as defined above and each Y can be the same or different and is selected from the group as defined for X or two Y together are —O— or a single bond.

12. Use of a supported catalyst obtained by the method of anyone of claims 1 to 7 or a catalyst of any one of claim 10 or 11 in alkene metathesis, in particular in the metathesis of functionalized alkenes.

13. A method for alkene metathesis comprising contacting a supported MO.sub.nE.sub.m catalyst, in particular a supported MO.sub.n catalyst, with a reductant as defined in any one of claims 1 to 5 and contacting said reduced catalyst with an alkene to be metathesized under metathesis conditions.

14. The method of claim 13 wherein the reduction reaction is performed in situ by simultaneously combining supported MO.sub.nE.sub.m catalyst, in particular supported MO.sub.n catalyst, reductant and alkene to be metathesized under metathesis conditions.

15. The method of claim 13 or 14, wherein the metathesis conditions are a temperature in the range of −20° C. to 500° C., preferably 40° C. to 250° C., more preferred at about 70° C., and the ratio of alkene substrate to M is 0.90001 to 1 mole of metal per mole of substrate.

16. The method of any one of claims 13 to 15, wherein the catalyst is regenerated in situ by reacting with reductant either separately or in situ according to claim 14. cm 17. A method for producing an activated supported catalyst, said method comprising contacting a supported catalyst of the type MO.sub.nE.sub.m, in particular of the type MO.sub.n with at least one organic reductant, said reductant being a compound of formula (I) ##STR00013## wherein R1 to R4, E1, n, X and Y are as defined in any one of claims 2 to 5, preferably the conditions are as defined in claim 6 and the supported catalyst preferably is as defined in claim 7.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0114] The invention will be better understood and objects other than those set forth above will become apparent from the following detailed description thereof. Such description makes reference to the annexed drawings.

[0115] FIG. 1. Thermal ellipsoid plot at the 50% probability of [WO.sub.2(OSi(OtBu).sub.3).sub.2(DME)]. Hydrogen atoms have been omitted and only one of the three independent molecules in the asymmetric unit has been represented for clarity.

[0116] FIG. 2. FTIR transmission spectra of [(≡SiO)WO.sub.2(OSi(OtBu).sub.3)]

[0117] FIG. 3. EXAFS spectrum of WO.sub.2(OSi(OtBu).sub.3).sub.2(DME).

[0118] FIG. 4. .sup.1H NMR spectrum (400 MHz, spinning rate 10 kHz, 4 mm rotor) of [(≡SiO)WO.sub.2(OSi(OtBu).sub.3)] (*: spinning side bands).

[0119] FIG. 5. .sup.13C CP-MAS NMR spectrum (400 MHz, spinning rate 10 kHz, 4 mm rotor) of [(≡SiO)WO.sub.2(OSi(OtBu).sub.3)] (d1=2s, contact time=2 ms).

[0120] FIG. 6. EXAFS spectrum of WO.sub.2(OSi(OtBu).sub.3).sub.2(DME) grafted onto [SiO.sub.2-700], i.e. [(≡SiO)WO.sub.2(OSi(OtBu).sub.3)].

[0121] FIG. 7. FTIR transmission spectra of [(≡SiO).sub.2WO.sub.2] (black line, (a)) compared with the parent [(≡SiO)WO.sub.2(OSi(OtBu).sub.3)] complex (grey line, (b)).

[0122] FIG. 8. EXAFS spectrum of WO.sub.2(OSi(OtBu).sub.3).sub.2(DME) grafted and thermally decomposed onto [SiO.sub.2-700], i.e. [(≡SiO).sub.2WO.sub.2].

[0123] FIG. 9. FTIR of the materials [(≡SiO).sub.2WO.sub.2](Red1).sub.0.5, (a), [(≡SiO).sub.2WO.sub.2](Red2).sub.0.5, (b), [(≡SiO).sub.2WO.sub.2](Red3).sub.0.5, (c) and [(≡SiO).sub.2WO.sub.2](Red4).sub.0.5, (d).

[0124] FIG. 10. FTIR of the materials [(≡SiO).sub.2WO.sub.2](Red4).sub.0.5, (d), [(≡SiO).sub.2WO.sub.2](Red4).sub.1, (c), [(≡SiO).sub.2WO.sub.2](Red4).sub.2, (b), and [(≡SiO).sub.2WO.sub.2](Red4).sub.3, (a).

[0125] FIG. 11. FTIR of the materials WO.sub.2Cl.sub.2(DME)/SiO.sub.2, (a), [(≡SiO).sub.2WO.sub.2].sub.Cl, (b) and [(≡SiO).sub.2WO.sub.2].sub.Cl(Red4).sub.2, (c).

[0126] FIG. 12. EXAFS spectrum of WO.sub.2Cl.sub.2(DME)/SiO.sub.2 thermally decomposed under vacuum, i.e. [(≡SiO).sub.2WO.sub.2].sub.Cl.

[0127] FIG. 13: FTIR of the materials [(≡SiO)MoO.sub.2{OSi(O.sup.tBu).sub.3}] (a) and [(≡SiO)MoO.sub.2] (b).

[0128] FIG. 14. EXAFS spectrum of MoO.sub.2[OSi(O.sup.tBu).sub.3].sub.2 (a), [(≡SiO)MoO.sub.2{OSi(O.sup.tBu).sub.3}] (b) and [(≡SiO)MoO.sub.2] (c).

[0129] FIG. 15. Conversion vs time, cis-4-nonene homometathesis, 0.1 mol % W, 70° C. for [(≡SiO)2WO.sub.2](Red4).sub.2 (diamonds), [(≡SiO).sub.2WO.sub.2](Red4); (empty circles), [(≡SiO)2WO.sub.2](Red4).sub.0.5 (crosses), [(≡SiO).sub.2WO.sub.2](Red1).sub.1 (empty squares) and [(≡Si(.sub.2WO.sub.2]+0.2 mol % Red4 (triangles).

[0130] FIG. 16. Conversion vs time, cis-4-nonene homometathesis, 0.1 mol % W, 70° C. for [(≡SiO).sub.2WO.sub.2] in presence of two equivalents of the following reagents: Red4 (diamonds), allyltrimethyilane (squares), cyclohexadiene (triangles), vinyltriethoxysilane (crosses) and 1,4-bistrimethylsilylbenzene (stars).

[0131] FIG. 17. Conversion, diethyl diallylmalonate ring closing metathesis, 0.1 mol % W, 70° C. for [(≡SiO).sub.2WO.sub.2]: 90h after initial addition of 2 equiv. of Red4 (a) and 90h after second addition of 2 equiv. of Red4 (b).

[0132] FIG. 18. Conversion vs time, cis-4-nonene homometathesis, 0.1 mol % W, 70° C. for [(≡SiO).sub.2WO.sub.2].sub.Cl in presence of two equivalents of Red4 (diamonds) and [(≡SiO).sub.2WO.sub.2].sub.Cl(Red4).sub.2 (squares).

[0133] FIG. 19. Conversion vs time, cis-4-nonene homometathesis, 0.1 mol % W, 30° C. for [(≡SiO)MoO.sub.2] in presence of two equivalents of Red4 (squares).

[0134] FIG. 20. Conversion vs time, cis-4-nonene homometathesis, 0.1 mol % W, 70° C. for Re.sub.2O.sub.7/SiO.sub.2 in absence (diamonds) and in presence of two equivalents of Red1 (squares).

MODES FOR CARRYING OUT THE INVENTION

Preliminary Remarks on Nomenclature

[0135] MO.sub.n/support designates any of the supported tungsten oxide, molybdenum oxide or rhenium oxide catalysts on any metal oxide support as defined above.

[0136] The designation catalyst/support indicates that the structure of the supported catalyst is not fully determined or that differently bound catalytical sites can be present.

[0137] (≡SiO) means an isolated siloxy group of the silica surface or three bonds ≡ of surface silica to the bulk, respectively.

[0138] [(≡SiO).sub.mMO.sub.n] means a determined structure with m siloxy groups bound to one metal center M.

Experimental Part

A) General Procedures

[0139] All experiments were carried out under dry and oxygen free argon atmosphere using either standard Schlenk or glove-box techniques. Pentane, toluene and diethyl ether were purified using double MBraun SPS alumina column, and were degassed using three freeze-pump-thaw cycles before being used. Dimethoxyethane (DME) and tetrahydrofuran (THF) were distilled from Na/Benzophenone. Silica (Aerosil Degussa, 200 m.sup.2g.sup.−1) was compacted with distilled water, calcined at 500° C. under air for 4 h and treated under vacuum (10.sup.−5 mbar) at 500° C. for 6 h and then at 700° C. for 10 h (support referred to as SiO.sub.2-(700)) and contained 0.26 mmol of OH per g as measured by titration with PhCH.sub.2MgCl. All infrared (IR) spectra were recorded using a Bruker spectrometer placed in the glovebox, equipped with OPUS software. A typical experiment consisted in the measurement of transmission in 32 scans in the region from 4000 to 400 cm.sup.−1. The .sup.1H and .sup.13C-NMR spectra were obtained on Bruker DRX 200, DRX 250 or DRX 500 spectrometers. The solution spectra were recorded in C.sub.6D.sub.6 at room temperature. The .sup.1H and .sup.13C chemical shifts are referenced relative to the residual solvent peak. Compounds WO.sub.2Cl.sub.2(DME),[1] WOCl.sub.4,[2] [MoO.sub.2(OSi(OtBu).sub.3).sub.2],[6] 1-methyl-3,6-bis(trimethylsilyl)-1,4-cyclohexadiene (Red1),[3] 1,4-bis(trimethylsilyl)-1,4-diaza-2,5-cyclohexadiene (Red2), 2,5-dimethyl-1,4-bis(trimethylsilyl)-1,4-diaza-2,5-cyclohexadiene (Red3), 2,3,5,6-tetramethyl-1,4-bis(trimethylsilyl)-1,4-diaza-2,5-cyclohexadiene (Red4),[4] were synthesized according to literature procedures. LiOSi(OtBu).sub.3 was obtained by deprotonation of HOSi(OtBu).sub.3 with n-BuLi according the published procedure.[6] Ammonium metatungstate and ammonium heptamolybdate hydrates were purchased from Fiuka and used without purification. WO.sub.3/SiO.sub.2 and MoO.sub.3/SiO.sub.2 were synthesized by incipient wetness impregnation followed by calcination at 450° C.[5] It was determined by elemental analysis to contain 7.12% W in mass for WO.sub.3/SiO.sub.2 and 7% Mo in mass for MoO.sub.3/SiO.sub.2. Re.sub.2O.sub.7/SiO.sub.2 was prepared according to a method described in [7]. Unless otherwise stated, reductions and catalytic tests were carried out at 70° C.

B) Syntheses and Characterisation of the Materials

B) I) Synthesis of the Molecular Precursors Involving Alkoholate Comprising Precursors:

[0140] Synthesis of [WO.sub.2(OSi(OtBu).sub.3).sub.2(DME)]

[0141] [WO.sub.2(OSi(OtBu).sub.3).sub.2(DME)] was synthesized using a modification of the procedure described by Tilley.[6]

[0142] A solution of LiOSi(OtBu).sub.3 (2.87 g, 10.6 mmol, 2 eq.) in cold toluene (15 mL, −40° C.) was added dropwise to a suspension of WO.sub.2Cl.sub.2(DME) (2 g, 5.3 mmol, 1. eq.) in toluene (20 mL, −78° C.) containing 200 μL of DME under vigorous stirring. After 1 hour stirring at −78° C. and 2 hours at room temperature, the solution was filtered through a short Celite® pad to afford a colorless solution. Crystallization of the product from this solution at −40° C. afforded 3.2 g (3.8 mmol, 72%) of the title product as large colorless needle shaped crystals suitable for XRD (collected in two crops).

[0143] .sup.1H-NMR (300 MHz, C6D6) δ1.38 (s, 54, (OtBu).sub.3), 3.15 (s, 6, DME), 3.33 (s, 4, DME).

[0144] IR (KBr, cm.sup.−1): 703(m), 830(m), 858(m), 902(m), 948(m), 962(m), 1028(m), 1066(s), 1191(m), 1243(m), 1366(m), 1390(m), 1473(w), 2975(m).

[0145] The XRD structure is shown in FIG. 1, Selected bonds for [WO.sub.2(OSi(OtBu).sub.3).sub.2(DME)] are listed in Table 1 (distances are given in Å) and crystallographic data for [WO.sub.2(OSi(OtBu).sub.3).sub.2(DME)] are presented in Table 2.

TABLE-US-00001 TABLE 1 (distances in Å): Structural parameters [WO.sub.2(OSi(OtBu).sub.3).sub.2(DME)] W1 - O1 1.719 (5) W1 - O2 1.716 (5) W1 - O3 1.924 (4) W1 - O4 1.928 (4) W1 - O5 2.332 (4) W1 - O6 2.344 (4)

TABLE-US-00002 TABLE 2 Formula C.sub.119H.sub.264O.sub.48Si.sub.8W.sub.4 Crystal size (mm) 0.7 × 0.2 × 0.2 cryst syst Tetragonal space group I41 volume (Å.sup.3) 16779.5 (4) a (Å) 23.6586 (3) b (Å) 23.6586 (3) c (Å) 29.9778 (5) α (deg) 90 β (deg) 90 γ (deg) 90 Z 4 formula weight (g/mol) 3423.44 density (g cm.sup.−3) 1.355 F(000) 7075.3 temp (K) 150.0 (3) total no. reflections 30830 unique reflections [R(int)] 23689 [0.1046] Final R indices [I > 2σ(I)] R.sub.1 = 0.0641, wR.sub.2 = 0.1208 Largest diff. peak and hole (e.A.sup.−3) 2.62/−3.91 GOF 1.050

[0146] An EXAFS (extended X-ray absorption fine structure) spectrum of WO.sub.2(OSi(OtBu).sub.3).sub.2(DME) is shown in FIG. 3 and the relevant data are listed below in Table 3.

TABLE-US-00003 TABLE 3 Scatterer N S02 r model delr R ss{circumflex over ( )}2 enot Oa 2 1 1.717 0.030 1.74 0.00493 4.52 Ob 2 1 1.926 −0.016 1.91 0.00081 4.52 Oc 2 1 2.338 0.038 2.38 0.0224 4.52 O 2x scatter 2 1 3.092 −0.025 3.07 0.00978 4.52 O 2x scatter 8 1 3.204 −0.025 3.18 0.00978 4.52 C 2 1 3.209 0.156 3.36 0.00978 4.52 C 2 1 3.270 0.156 3.42 0.00978 4.52 Si 1 1 3.348 0.156 3.50 0.00978 4.52 Si 1 1 3.378 0.156 3.53 0.00978 4.52
Synthesis of [(≡SiO)WO.sub.2(OSi(O.sup.tBu).sub.3)]

[0147] A solution of 1 g of WO.sub.2[OSi(OtBu).sub.3].sub.2(DME) (1.25 mmol, 1.05 equiv.) in benzene (6 mL) was added to a suspension of SiO.sub.2-(700) (4.61 g, 1.19 mmol, 1 equiv.) in benzene (3 mL) at room temperature. The suspension was slowly stirred at room temperature for 12 h. The white solid was collected by filtration, and was washed by five suspension/filtration cycles in benzene (5×2 mL). The resulting solid was dried thoroughly under high vacuum (10.sup.−5 mbar) at room temperature for 3h to afford 4.55 g of the title compound. All the filtrate solutions were collected and analyzed by .sup.1H NMR spectroscopy in C.sub.6D.sub.6 using ferrocene as internal standard, indicating that 0.7 mmol of (.sup.tBuO).sub.3SiOH and 0.47 mmol of DME were released upon grafting (0.60 equiv. (.sup.tBuO).sub.3SiOH and 0.40 equiv.DME). Additional 0.65 mmol of DME were quantified in the volatiles collected upon high vacuum drying, indicating that >95% of DME was not retained on the silica surface.

[0148] Elemental Analysis: W 3.36%, C 2.77%, H 0.74% corresponding to 12.6 C/W (12 expected), 40.2 H/W (39 expected).

[0149] IR (KBr, cm.sup.−1): 1369 (s), 1393 (m), 1474 (w), 2937 (m, sh), 2979 (s).

[0150] The FTIR transmission spectra of [(≡SiO)WO.sub.2(OSi(OtBu).sub.3)] is shown in FIG. 2.

[0151] The .sup.1H NMR spectrum (400 MHz, spinning rate 10 kHz, 4 mm rotor) of [(≡SiO)WO.sub.2(OSi(OtBu).sub.3)] (*: spinning side bands) is shown in FIG. 4.

[0152] The .sup.13C CP-MAS NMR spectrum (400 MHz, spinning rate 10 kHz, 4 mm rotor) of [(≡SiO)WO.sub.2(OSi(OtBu).sub.3)] (d1=2s, contact time=2 ms) is shown in FIG. 5.

[0153] An EXAFS (extended X-ray absorption fine structure) spectrum of WO.sub.2(OSi(OtBu).sub.3).sub.2(DME) grafted onto [SiO.sub.2-700], [(≡SiO)WO.sub.2(OSi(OtBu).sub.3)], is shown in FIG. 6 and the relevant data are listed below in Table 4.

TABLE-US-00004 TABLE 4 Scatterer N S02 r model delr R ss{circumflex over ( )}2 enot Oa 2 1 1.717 0.0407 1.76 0.00604 6.87 Ob 2 1 1.926 −0.00354 1.92 0.00118 6.87 O 2x scatter 2 1 3.092 −0.103 2.99 0.0162 6.87 O 2x scatter 8 1 3.204 −0.103 3.10 0.0162 6.87
Thermal Decomposition of [(SiO)WO.sub.2(OSi(OtBu).sub.3)]: Preparation of [(≡SiO).sub.2WO.sub.2]

[0154] [(≡SiO)WO.sub.2(OSi(OtBu).sub.3)] (3.0 g) was loaded into a reactor and placed under high vacuum (10.sup.−5 mbar) and heated to 200° C. (1° C./min) and kept at 200° C. for 3 h, then heated to 400° C. (1° C./min) and kept at 400° C. for 6 h. The reactor was cooled to ambient temperature under vacuum, and [(≡SiO).sub.2WO.sub.2] was stored in an Ar filled glovebox. The volatiles liberated during this process were quantified by .sup.1H NMR in C6D6 with ferrocene as an internal standard as 2.5 equiv of isobutylene, 0.6 equiv. of water and 0.8 equiv of tBuOH per surface W complex.

[0155] Elemental analysis: W 3.56%.

[0156] IR (KBr, cm.sup.−1): 3746 (s).

[0157] FTIR transmission spectra of [(≡SiO).sub.2WO.sub.2] (grey line, (b)) compared with the parent [(≡SiO)WO.sub.2(OSi(OtBu).sub.3)] complex (black line, (a)) is shown in FIG. 7.

[0158] An EXAFS (extended X-ray absorption fine structure) spectrum of WO.sub.2(OSi(OtBu).sub.3).sub.2(DME) grafted and thermally decomposed onto [SiO.sub.2-700], [(□SiO).sub.2WO.sub.2], is shown in FIG. 8 and the relevant data are listed below in Table 5.

TABLE-US-00005 TABLE 5 Scatterer N S02 r model delr R ss{circumflex over ( )}2 enot O 2 1 1.717 0.0083 1.73 0.00334 6.50 O 2 1 1.926 −0.022 1.90 0.00122 6.50

[0159] For the reduction of the materials, organosilicon reductants of the following formula (II) were primarily used:

##STR00006##

[0160] wherein E.sup.1 is CH or N, R.sup.1, R.sup.2, R.sup.7 and R.sup.8 are H or CH.sub.3 and R.sup.6 is SiX3 and X is methyl.

[0161] In particular the following reductants were used in the Examples:

##STR00007##

[0162] The general reaction scheme using such compounds of formula (II) is as follows:

##STR00008##

Representative Procedure: Reduction of [(≡SiO).sub.2WO.sub.2] with 1 Equiv. of 2,6 trimethylsilyl tetramethyl diazacyclohexadiene (Red4).

[0163] A solution of 5.4 mg of Red4 (19 μmol, 1 equiv.) in benzene (0.5 mL) was added to a suspension of [(≡SiO).sub.2WO.sub.2] (100 mg, 19 μmol) in benzene (0.5 mL) at room temperature. The suspension was slowly stirred at 70° C. for 12h, resulting in color change of the material from colorless to dark violet. The solid was collected by filtration, and was washed by four suspension/filtration cycles in benzene (4×1 mL). The resulting dark violet solid was dried thoroughly under high vacuum (10.sup.−5 mbar) at room temperature for 3h to afford 90 mg of the title compound. All the filtrate solutions were collected and analyzed by .sup.1H NMR spectroscopy in C.sub.6D.sub.6 using ferrocene as internal standard, indicating full consumption of Red4 and that 0.011 mmol of 1,2,4,5-tetramethylpyrazine and 0.006 mmol of hexamethyldisiloxane (HMDSO) were released upon reacting (0.55 equiv. 1,2,4,5-tetramethylpyrazine).

Reduction of [(≡SiO).sub.2WO.sub.2] with 1 Equiv. of Reductant Red1-Red4:

[0164] The reductions were carried out following the procedure above. 100 mg of [(≡SiO).sub.2WO.sub.2] were reduced with 1 equiv. of the four reductants represented above. Analyses of the filtrate by NMR are summarized in Table 6:

TABLE-US-00006 TABLE 6 Colour Consumption Aromatized of the Reductant of Red. Bp (Ar) HMDSO material Material name Red1  10% 10% 1% Blue [(≡SiO).sub.2WO.sub.2](Red1).sub.1 Red2 100%  1% 2% Dark [(≡SiO).sub.2WO.sub.2](Red2).sub.1 violet Red3 100% 33% 4% Dark [(≡SiO).sub.2WO.sub.2](Red3).sub.1 violet Red4 100% 55% 3% Dark [(≡SiO).sub.2WO.sub.2](Red4).sub.1 violet FTIR of the materials [(≡SiO).sub.2WO.sub.2](Red1).sub.1, (a), [(≡SiO).sub.2WO.sub.2](Red2).sub.1, (b), [(≡SiO).sub.2WO.sub.2](Red3).sub.1, (c), and [(≡SiO).sub.2WO.sub.2](Red4).sub.1, (d) are shown in FIG. 9.
Reduction of [(≡SiO).sub.2WO.sub.2] with Different Equiv. of Reductant Red4:

[0165] The reductions were carried out following the procedure above. 100 mg of [(≡SiO).sub.2WO.sub.2] were reduced with various amounts of reductant Red4. Analyses of the filtrate by NMR are summarized in Table 7:

TABLE-US-00007 TABLE 7 Equiv. of Consump- Aroma- Red4 per tion tized W center of Red4 Bp (Ar) HMDSO Material name 0.5 100% 29% 3% [(≡SiO).sub.2WO.sub.2](Red4).sub.0.5 0.8 100% 40% 3% [(≡SiO).sub.2WO.sub.2](Red4).sub.0.8 0.9 100% 46% 3% [(≡SiO).sub.2WO.sub.2](Red4).sub.0.9 1 100% 55% 3% [(≡SiO).sub.2WO.sub.2](Red4).sub.1 2  68% 50% 6% [(≡SiO).sub.2WO.sub.2](Red4).sub.2 3  62% 29% 4% [(≡SiO).sub.2WO.sub.2](Red4).sub.3 4  60% 26% 3% [(≡SiO).sub.2WO.sub.2](Red4).sub.4 FTIR of the materials [(≡SiO).sub.2WO.sub.2](Red4).sub.0.5, (d), [(≡SiO).sub.2WO.sub.2](Red4).sub.1, (c), [(≡SiO).sub.2WO.sub.2](Red4).sub.2, (b), and [(≡SiO).sub.2WO.sub.2](Red4).sub.3, (a) are shown in FIG. 10.
B) II) Synthesis of the Molecular Precursors without Involving Alkoholate Comprising Precursors:
Synthesis of WO.sub.2Cl.sub.2(DME)/SiO.sub.2

[0166] A solution of 117.6 mg of WO.sub.2Cl.sub.2(DME) (0.312 mmol, 1.2 equiv.) in benzene (4 mL) was added to a suspension of SiO.sub.2-(700) (1 g, 0.26 mmol, 1 equiv.) in benzene (3 mL) at room temperature. The suspension was slowly stirred at room temperature for 12 h. The light green solid was collected by filtration, and was washed by five suspension/filtration cycles in benzene (5×3 mL). The resulting solid was dried thoroughly under high vacuum (10.sup.−5 mbar) at room temperature for 3h to afford 1.05 g of the title compound. All the filtrate solutions were collected and analyzed by .sup.1H NMR spectroscopy in C.sub.6D.sub.6 using ferrocene as internal standard, indicating that 0.072 mmol of WO.sub.2Cl.sub.2(DME) and 0.096 mmol of DME were released upon grafting.

[0167] Elemental Analysis: W 4.35%, C 0.75%, H 0.4% corresponding to 3 C/W (4 expected for the DME adduct), 12 H/W (10 expected for the DME complex).

[0168] The FTIR transmission spectra of WO.sub.2Cl.sub.2(DME)/SiO.sub.2 is shown in FIG. 11(a).

Thermal Decomposition of WO.sub.2Cl.sub.2(DME)/SiO.sub.2:

[0169] Preparation of [(SiO).sub.2WO.sub.2].sub.Cl (in this and following formulas the index .sub.Cl designates that the catalyst has been obtained using a chloride comprising precursor)

[0170] WO.sub.2Cl.sub.2(DME)/SiO.sub.2 (1.0 g) was loaded into a reactor and placed under high vacuum (10.sup.−5 mbar) and heated to 200° C. (1° C./min) and kept at 200° C. for 3 h, then heated to 400° C. (1° C./min) and kept at 400° C. for 12 h The reactor was cooled to ambient temperature under vacuum, and [(≡SiO).sub.2WO.sub.2].sub.Cl was stored in an Ar filled glovebox.

[0171] Elemental analysis: W 4.56%.

[0172] The FTIR transmission spectra of [(≡SiO).sub.2WO.sub.2].sub.Cl is shown in FIG. 11(b).

[0173] An EXAFS (extended X-ray absorption fine structure) spectrum of WO.sub.2Cl.sub.2(DME) grafted and thermally decomposed onto [SiO.sub.2-700], [(≡SiO).sub.2WO.sub.2].sub.Cl, is shown in FIG. 12 and the relevant data are listed below in Table 8.

TABLE-US-00008 TABLE 8 Scatterer N S02 r model delr R ss{circumflex over ( )}2 enot O 2 0.852 1.6879 0.002826 1.716 0.00311 4.524 O 2 0.852 1.900 −0.00480 1.895 0.00131 4.524
Reduction of [(≡SiO).sub.2WO.sub.2].sub.Cl with 1 Equiv. of Reductant Red4:

[0174] The reductions were carried out following the procedure described for [(≡SiO).sub.2WO.sub.2](Red4).sub.2. 100 mg of [(≡SiO).sub.2WO.sub.2].sub.Cl were reduced with 2 equiv. of the reductant Red4. Analysis of the filtrate by NMR is given in table 9: The FTIR transmission spectra of [(≡SiO).sub.2WO.sub.2].sub.Cl(Red4).sub.2 is shown in FIG. 11(c).

TABLE-US-00009 TABLE 9 Colour Consumption Aromatized of the Reductant of Red. Bp (Ar) HMDSO material Material name Red4 64% 48% 7% Dark [(≡SiO).sub.2WO.sub.2].sub.Cl(Red4).sub.2 violet

Preparation of [(≡SiO)MoO.SUB.2.]:

[0175] Grafting of MoO.sub.2[OSi(O.sup.tBu).sub.3].sub.2 on SiO.sub.2-700 with DME

[0176] A solution of MoO.sub.2[OSi(O.sup.tBu).sub.3].sub.2 (301 mg, 0.46 mmol) and DME (0.3 mL) in benzene (10 mL) was added slowly to a suspension of SiO.sub.2-700 (1.71 g, 0.44 mmol SiOH) in benzene (5 mL). The mixture was stirred for 1 day at room temperature and then turned light yellow. The solution was decanted and the solid was washed with benzene four times. All the filtrate solutions were collected and analyzed by .sup.1H NMR spectroscopy in C6D6 using ferrocene as internal standard, indicating that 0.28 mmol of MoO.sub.2[OSi(O.sup.tBu).sub.3].sub.2 and 0.14 mmol of HOSi(OtBu).sub.3 were present in the filtrate after grafting. Drying the solid obtained under high vacuum for 5 h afforded [(≡SiO)MoO.sub.2{OSi(O.sup.tBu).sub.3}] as a white solid (1.83 g).

[0177] Elemental Analysis: Mo 1.03%, C 1.25%, H 0.29% corresponding to 10 C/W (12 expected), 27 H/W (27 expected).

Thermal Decomposition of [(≡SiO)MoO.sub.2{OSi(O.sup.5Bu).sub.3}]

[0178] [(≡SiO)MoO.sub.2{OSi(O.sup.5Bu).sub.3}] (1.0 g) was loaded into a reactor and placed under high vacuum (10.sup.−5 mbar) and heated to 200° C. (1° C./min) and kept at 200° C. for 3 h, then heated to 400° C. (1° C./min) and kept at 400° C. for 12 h. The color of the solid changed to light gray. The solid was thermally treated in dry air (0.3 atm) at 300° C. for 3 h to afford [(≡SiO)MoO.sub.2] as a white solid. The reactor was cooled to ambient temperature under vacuum, and [(≡SiO)MoO.sub.2] was stored in an Ar filled glovebox.

[0179] Elemental Analysis: Mo 1.22%

[0180] The FTIR transmission spectra of [(≡SiO)MoO.sub.2{OSi(O.sup.tBu).sub.3}] and [(≡SiO)MoO.sub.2] are shown in FIGS. 13(a) and 13(b), respectively.

[0181] EXAFS (extended X-ray absorption fine structure) spectra of MoO.sub.2[OSi(O.sup.tBu).sub.3].sub.2, [(≡SiO)MoO.sub.2{OSi(O.sup.tBu).sub.3}] and [(≡SiO)MoO.sub.2] are shown in FIG. 14 and the relevant data are listed below in Table 10.

TABLE-US-00010 TABLE 10 Scatterer N S02 r model delr R ss{circumflex over ( )}2 enot MoO.sub.2[OSi(O.sup.tBu).sub.3].sub.2 O1.1 2 1.145 1.6904 0.0066 1.697 0.00087 6.439 O2.1 2 1.145 1.8159 0.04519 1.86109 0.00087 6.439 Si1.1 2 1.145 3.4483 0.16669 3.61499 0.01244 6.439 O2.1 Si1.1 4 1.145 3.4659 −0.01243 3.45347 0.02524 6.439 O2.1 Si1.1 O2.1 2 1.145 3.4836 −0.01243 3.47117 0.02524 6.439 [(≡SiO)MoO.sub.2{OSi(O.sup.tBu).sub.3}] O 2 1.145 1.6904 0.04948 1.739 0.00232 4.616 O 2 1.145 1.8159 0.14283 1.958 0.00232 4.616 [(≡SiO).sub.2MoO.sub.2] O 2 1.145 1.6904 0.01842 1.708 0.00074 −1.995 O 2 1.145 1.8159 0.1007 1.917 0.00074 −1.995
Reduction of [(≡SiO).sub.2MoO.sub.2] with 2 equiv. of Reductant Red4:

[0182] The reductions were carried out following the procedure described for [(≡SiO).sub.2WO.sub.2](Red4).sub.2. 265 mg of [(≡SiO).sub.2MoO.sub.2] were reduced with 2 equiv. of the reductant Red4. Analysis of the filtrate by NMR is given in Table 11.

TABLE-US-00011 TABLE 11 Colour Consumption Aromatized of the Reductant of Red. Bp (Ar) HMDSO material Material name Red4 99% 70% 6.5% Dark [(≡SiO).sub.2MoO.sub.2](Red4).sub.2 violet
Preparation of Re.sub.2O.sub.7/SiO.sub.2

[0183] As already indicated in the general procedures, the rhenium/silica was prepared according to the literature procedure described in [7]

C) Catalytic Activity

EXAMPLE 1

[0184] At t=0 a solution of cis-non-4-ene in toluene was introduced in a glass vial containing [(m5i0).sub.2WO.sub.2](Red4).sub.2 produced as described above with a molar ratio of alkene:metal centers of 1000:1. The reaction mixture was stirred at 70° C.; 5 μL aliquots of the solution were sampled and the reaction products over time were analysed. Full conversion was observed in less than 12h, with >99% selectivity.

EXAMPLE 2

[0185] At t=0 a 0.97 M solution of cis-non-4-ene in toluene (339 μL) containing heptane as internal standard (0.11 M) and 2 equivalents of Red4 (with respect to W centers, 0.658 μmol, 0.185 mg) was added to 1.7 mg (0.329 μmol) of the catalyst [(≡SiO).sub.2WO.sub.2] introduced in a conical base vial containing a wing shaped magnetic stirring bar. The reaction mixture was stirred at 600 rpm and kept at 70° C. using an aluminum heating block. 5 μL aliquots of the solution were sampled, diluted with pure toluene (100 μL) and quenched by the addition of 1 μL of wet ethyl acetate. The resulting solution was analyzed by GC/FID (Agilent Technologies 7890 A) equipped with an HP-5 (Agilent Technologies) column.

[0186] Full conversion was observed in less than 3h, with >99% selectivity.

EXAMPLE 3

[0187] In a manner similar to the one described in Example 1, cis-4-nonene (1000 equivalents) was metathesized using [(≡SiO).sub.2WO.sub.2](Red1).sub.0.5 instead of [(≡SiO).sub.2WO.sub.2](Red4).sub.2.

[0188] Full conversion was observed in less than 12h, with >99% selectivity.

EXAMPLE 4

[0189] In a manner similar to the one described in Example 2 and using 100 equivalents (with respect to the tungsten centres) of ethyl oleate in toluene and 2 equivalents of Red4 with 1 equivalent of [(≡SiO).sub.2WO.sub.2], ethyl oleate (100 equivalents) was metathesized to full conversion in less than 24h, with >99% selectivity.

EXAMPLE 5

Examples 2 and 4 were repeated except that no organosilicon reductant was added to the reaction mixture. No reaction products could be observed after 24h.

[0190] The above data clearly demonstrate the significant advantage obtained with the catalysts treated with the organosilicon reductants; an unactivated tungsten oxide catalyst did not show any activity in the conditions tested above, while catalysts treated with organosilion reductants demonstrated high activity in alkene metathesis. Highest activity was obtained when the organosilicon reagent was added together with the olefin substrate although independant reduction also resulted in increased activity.

EXAMPLE 6

Investigation of Different Precursors

a) Molecular Precursors

[0191] In a manner similar to the one described in Example 2, cis-4-nonene (1000 equivalents) was metathesized using toluene solutions of one equivalent of molecular precursors (given below) treated with two equivalents of Red4 at 70° C. Conversions are reported in Table 12. For all the precursors listed in Table 8, no activity was observed in absence of reductant.

TABLE-US-00012 TABLE 12 TOF.sub.3 min TOF.sub.max Conversion Catalyst (min.sup.−1) (min.sup.−1).sup.a at 24 h WCl.sub.6 <0.1 <0.1  2.6% .sup.b WOCl.sub.4 <0.1 <0.1  .sup. >1% .sup.b WO.sub.2Cl.sub.2(DME) <0.1 <0.1 1.5%  WO(OSi(OtBu).sub.3).sub.4 <0.1 <0.1 >1% WO.sub.2(OSi(OtBu).sub.3).sub.2(DME) <0.1 <0.1 >1% .sup.aMaximum TOF (turn over frequency) determined during the test. Values in bracket are the time for which maximum TOF was observed. .sup.b Full isomerisation of the substrate to thermodynamic Z/E ratio was observed with this substrate.

b) Heterogeneous Catalysts

[0192] In a manner similar to the one described in example 2, cis-4-nonene (1000 equivalents with respect to metal centers) was metathesized using heterogeneous catalysts (given below) treated with two equivalents of Red4 (per metal centers). Conversions are reported in Table 13. For all the precursors listed in Table 13, negligible activity was observed in the absence of reductant.

TABLE-US-00013 TABLE 13 TOF.sub.3 min TOF.sub.max Time to Catalyst (0.1 mol % W) (min.sup.−1) (min.sup.−1).sup.a conversion [(≡SiO).sub.2WO.sub.2] 3 8 (10 min) 3 h WO.sub.3/SiO.sub.2 1  2 (320 min) 24 h MoO.sub.3/SiO.sub.2 0.5 0.6 (60 min).sup.  24 h [(≡SiO)WO.sub.2(OSi(OtBu).sub.3)] 0.3 0.3 (3 min)   10% conversion after 24 h .sup.aMaximum TOF (turn over frequency) determined during the test. Values in bracket are the time for which maximum TOF was observed.

EXAMPLE 7

Metathesis of cis-non-4-ene by Pre-Reduced Materials [(≡SiO).SUB.2.WO.SUB.2.](Redn).SUB.x

[0193] At t=0 a 0.97 M solution of cis-non-4-ene in toluene (379 μL for [(≡SiO).sub.2WO.sub.2](Red 1).sub.1, 539 μL for [(≡SiO).sub.2WO.sub.2](Red 4).sub.0.5, 339 μL for [(≡SiO).sub.2WO.sub.2](Red 4).sub.1, 399 μL for [(≡SiO).sub.2WO.sub.2](Red 4).sub.2) containing heptane as internal standard (0.11 M) was added to the catalyst ((1.9 mg of [(≡SiO).sub.2WO.sub.2](Red 1).sub.1, 2.7 mg of [(≡SiO).sub.2WO.sub.2](Red 4).sub.0.5, 1.7 mg of [(≡SiO).sub.2WO.sub.2](Red 4).sub.1 or 2.0 mg of [(≡SiO).sub.2WO.sub.2](Red 4).sub.2) introduced in a conical base vial containing a wing shaped magnetic stirring bar. The reaction mixture was stirred at 600 rpm and kept at 70° C. using an aluminum heating block. 5 μL aliquots of the solution were sampled, diluted with pure toluene (100 μL) and quenched by the addition of 1μL of wet ethyl acetate. The resulting solution was analyzed by GC/FID (Agilent Technologies 7890 A) equipped with an HP-5 (Agilent Technologies) column. The results are listed in Table 14.

TABLE-US-00014 TABLE 14 TOF.sub.3 min TOF.sub.max Time to final Catalyst (0.1 mol % W) (min.sup.−1) (min.sup.−1).sup.a conversion [(≡SiO).sub.2WO.sub.2](Red1).sub.1 17 17 (3 min)  12 h [(≡SiO).sub.2WO.sub.2](Red4).sub.0.5 5 8 (10 min) 3 h [(≡SiO).sub.2WO.sub.2](Red4).sub.1 2 3 (10 min) 6 h [(≡SiO).sub.2WO.sub.2](Red4).sub.2 <1  2 (540 min) 12 h .sup.aMaximum TOF determined during the test. Values in bracket give the time at which maximum TOF was observed.

[0194] A visual presentation of conversion vs time of cis-4-nonene homometathesis using 0.1 mol % W, 70° C. is given in FIG. 15 for [(≡SiO).sub.2WO.sub.2] (Red4).sub.2 (diamonds), [(≡SiO).sub.2WO.sub.2] (Red4).sub.1 (empty circles), [(≡SiO).sub.2WO.sub.2] (Red4).sub.0.5 (crosses), [(≡SiO).sub.2WO.sub.2](Red1).sub.1 (empty squares) and [(≡SiO).sub.2WO.sub.2]+0.2 mol % Red4 (triangles)

EXAMPLE 8

Metathesis of Functionalized Olefins by [(≡SiO).SUB.2.WO.SUB.2.] in Presence of 2 Equiv. of Red4 at 70° C.

[0195] Following the procedure described in Examples 2 and 4, metathesis of further olefin substrates has been investigated. The results are listed in Table 15.

TABLE-US-00015 TABLE 15 TOF.sub.max Time to final Substrate Mol % (min.sup.−1) conversion Cis-4-nonene 0.1  8 (10 min) 3 h Ethyl Oleate 1 4 (3 min) <24 h Cyclooctene 1 10 (5 min)  20 min Diethyl Diallylmalonate 1 <0.1 15% at 24 h Phenylpropyne 1 <0.1  7% at 24 h

EXAMPLE 9

Metathesis of cis-non-4-ene by [(≡SiO).SUB.2.WO.SUB.2.] 0.1 mol % in Presence of 2 Equiv. of Other Reagents (toluene, 70° C.).

[0196] Metathesis of cis-non-4-ene with organic reductants different from organosilicon reductants of Formula (II) has been performed as described in Example 2, using [(≡SiO).sub.2WO.sub.2], 0.1 mol % in the presence of 2 equiv. of reductant. The results are shown in Table 16.

TABLE-US-00016 TABLE 16 TOF.sub.max Time to final reagent (min.sup.−1) conversion Red4     8 (10 min) 3 h allylTMS  .sup.  4 (3 min) 24 h cyclohexadiene 0.8 (18 h) 24 h 1,4-bis(TMS)benzene 0.6 (18 h) 22 h

[0197] A visual presentation of conversion vs time of cis-4-nonene homometathesis, 0.1 mol % W, 70° C. for [(≡SiO).sub.2WO.sub.2] in presence of two equivalents of the following reagents: Red4 (diamonds), allyltrimethyilane (squares), cyclohexadiene (triangles), and 1,4-bistrimethylsilylbenzene (stars) in FIG. 16.

EXAMPLE 10

Recycling of Spent [(≡SiO).SUB.2.WO.SUB.2.] Catalyst with 2 Equiv. of Red4 at 70° C.

[0198] Metathesis of diethyl diallylmalonate was carried out following the procedure described in Example 8 (with 1. mol % catalyst [((≡SiO).sub.2WO.sub.2], 2 equiv. of Red4, 70° C., in toluene). After 90 h, 18% conversion was observed but no activity could be further detected. To this deactivated catalyst were added two equivalents of Red4, reinitiating catalytic activity, to reach 45% conversion 90h after the addition. The results are presented in FIG. 17: conversion 90h after initial Red4 addition (a) and 90h after second addition of 2 equiv. of Red4 (b).

EXAMPLE 11

[0199] At t=0 a 0.81 M solution of cis-non-4-ene in toluene (457 μL) containing heptane as internal standard (0.10 M) and 2 equivalents of Red4 (with respect to W centers, 0.744 μmol, 0.210 mg) was added to 1.5 mg (0.372 μmol) of the catalyst [((≡SiO).sub.2WO.sub.2].sub.Cl introduced in a conical base vial containing a wing shaped magnetic stirring bar. The reaction mixture was stirred at 600 rpm and kept at 70° C. using an aluminum heating block. 5 μL. aliquots of the solution were sampled, diluted with pure toluene (100 μL) and quenched by the addition of 1μL of wet ethyl acetate. The resulting solution was analyzed by GC/FID (Agilent Technologies 7890 A) equipped with an HP-5 (Agilent Technologies) column.

[0200] Conversion to the thermodynamic equilibrium was observed in less than 3h, with >99% selectivity. A plot of conversion vs. time is given in FIG. 18.

EXAMPLE 12

[0201] At t=0 a 0181 M solution of cis-non-4-ene in toluene (488 μL) containing heptane as internal standard (0.10 M) was added to 1.6 mg (0.396 μmol) of the catalyst [((≡SiO).sub.2WO.sub.2].sub.Cl(Red4).sub.2 introduced in a conical base vial containing a wing shaped magnetic stirring bar. The reaction mixture was stirred at 600 rpm and kept at 70° C. using an aluminum heating block. 5 μL aliquots of the solution were sampled, diluted with pure toluene (100 μL) and quenched by the addition of 1 μL of wet ethyl acetate. The resulting solution was analyzed by GC/FID (Agilent Technologies 7890 A) equipped with an HP-5 (Agilent Technologies) column.

[0202] Full conversion was observed in less than 24h, with >99% selectivity. A plot of conversion vs. time is given in FIG. 18.

EXAMPLE 13

Ethyl oleate Self-Metathesis with [((≡SiO).SUB.2.WO.SUB.2.].SUB.Cl

[0203] In a manner similar to the one described in Example 2 and using 100 equivalents (with respect to the tungsten centres) of ethyl oleate in toluene and 2 equivalents of Red4 with 1 equivalent of [((≡SiO).sub.2WO.sub.2Cl], ethyl oleate (100 equivalents) was converted to the thermodynamic equilibrium in less than 24h, with >99% selectivity.

EXAMPLE 14

Butene/ethylene Cross-Metathesis with [(≡SiO).SUB.2.WO.SUB.2.](Red4).SUB.2

[0204] A pellet of the solid [(SiO).sub.2WO.sub.2](Red4).sub.2 (5.4 μmol) was loaded in a flow reactor in the glove box, the isolated reaction chamber was then connected to the gas line. Tubes were flushed with the gas mixture (butene:ethylene:nitrogen 1:1:12 mol ratio) for 2 h. Before opening to the reaction chamber, the flow rate was set to 60 μmol/min for both ethylene and butene (11 mol alkene.mol.sub.w.sup.−1.min.sup.−1), the temperature was set to 100° C. The opening of the valve corresponds to the beginning of the catalysis and the reaction was monitored by GC using an auto-sampler. 13% conversion was observed after 3h reaction time with 99% selectivity for propene formation.

EXAMPLE 15

Ethyl oleate ethenolysis

[0205] A 1 mL of ethyl oleate containing octadecane as internal standard was added to 72 mg (14 μmol) of the catalyst [((≡SiO)2WO.sub.2] in a 10 mL vial and pressurized with 10 Bar ethylene. The reaction mixture was stirred at 600 rpm and kept at 80° C. during the reaction. At t=0, 2 a solution of 2 equivalents of Red4 in 1 mL toluene was added to the reaction mixture. After 24h reaction, the catalyst was quenched by addition of 100 μL of wet ethyl acetate. The resulting solution was analyzed by GC/FID (Agilent Technologies 7890 A) equipped with an HP-88 (Agilent Technologies) column. The catalyst reached 20% conversion with 92% selectivity for the ethenolysis products.

EXAMPLE 16

[0206] At t=0 a 0.95 M solution of cis-non-4-ene in toluene (400 μL) containing heptane as internal standard (0.10 M) and 2 equivalents of Red4 (with respect to Mo centers, 0.762 μmol, 0.220 mg) was added to 3 mg (0.380 μmol) of the catalyst [((≡SiO).sub.2MoO.sub.2] introduced in a conical base vial containing a wing shaped magnetic stirring bar. The reaction mixture was stirred at 600 rpm and kept at 30° C. using an aluminum heating block. 5 μL aliquots of the solution were sampled, diluted with pure toluene (100 μL) and quenched by the addition of 1 μL of wet ethyl acetate. The resulting solution was analyzed by GC/FID (Agilent Technologies 7890 A) equipped with an HP-5 (Agilent Technologies) column.

[0207] Full conversion was observed in less than 24h, with >99% selectivity. A plot of conversion vs. time is given in FIG. 19. When a similar test is carried out in the absence of reductant, no catalytic activity is observed.

EXAMPLE 17

[0208] In Absence of Reductant:

[0209] At t=0 a 0.95 M solution of cis-non-4-ene in toluene (401 μL) containing heptane as internal standard (0.10 M) was added to 1.4 mg (0.39 μmol) of the catalyst Re.sub.2O.sub.7/SiO.sub.2 introduced in a conical base vial containing a wing shaped magnetic stirring bar. The reaction mixture was stirred at 600 rpm and kept at 70° C. using an aluminum heating block. 5 μL aliquots of the solution were sampled, diluted with pure toluene (100 μL) and quenched by the addition of 1 μL of wet ethyl acetate. The resulting solution was analyzed by GC/FID (Agilent Technologies 7890 A) equipped with an HP-5 (Agilent Technologies) column. 12% conversion was observed in 24h, with >90% selectivity. A plot of conversion vs. time is given in FIG. 20.

[0210] In Presence of Two Equivalents of Red1:

[0211] At t=0 a 0.95 M solution of cis-non-4-ene in toluene (573 4) containing heptane as internal standard (0.10 M) and 2 equivalents of Red1 (with respect to Re centers, 1.1 μmol, 0.26 mg) was added to 2.0 mg (0.55 μmol) of the catalyst Re.sub.2O.sub.7/SiO.sub.2 introduced in a conical base vial containing a wing shaped magnetic stirring bar. The reaction mixture was stirred at 600 rpm and kept at 70° C. using an aluminum heating block. 5 μL aliquots of the solution were sampled, diluted with pure toluene (100 μL) and quenched by the addition of 1 μL of wet ethyl acetate. The resulting solution was analyzed by GC/FID (Agilent Technologies 7890 A) equipped with an HP-5 (Agilent Technologies) column. 41% conversion was observed in 24h, with >90% selectivity. A plot of conversion vs. time is given in FIG. 20.

EXAMPLE 18

[0212] Neat 9-methyl decenoate (310 μL., 1.48 mmol) was added to 5.3 mg (2.8 μmol) of the catalyst MoO.sub.3/SiO.sub.2 introduced in a vial containing a magnetic stirring bar. At t=0, 2 equivalents of Red4 (with respect to Mo centers, 5.6 μmol, 1.6 mg, as 0.1 M solution in toluene) was added to the reaction mixture. The reaction mixture was stirred at 100 rpm and kept at 150° C. using an aluminum heating block.

[0213] 57% conversion was observed in less than 24h, with >99% selectivity. When a similar test is carried out in the absence of reductant, no catalytic activity is observed.

EXAMPLE 19

[0214] Neat 9-methyl dodecenoate (E/Z=85/15) (355 μL, 1.45 mmol) was added to 5.3 mg (2.8 μmol) of the catalyst MoO.sub.3/SiO.sub.2 introduced in a vial containing a magnetic stirring bar. At t=0, 2 equivalents of Red4 (with respect to Mo centers, 5.6 μmol, 1.6 mg, as 0.1 M solution in toluene) was added to the reaction mixture. The reaction mixture was stirred at 100 rpm and kept at 150° C. using an aluminum heating block.

[0215] 22% conversion was observed in less than 24h, with 94% selectivity. When a similar test is carried out in the absence of reductant, no catalytic activity is observed.

REFERENCES

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