PDO or BMTZ ligand for supported coordinated PT hydrosilylation catalysts

Abstract

The invention describes single-site metal catalysts such as Pt single-site centers on powdered oxide supports with a 1,10-phenanthroline-5,6-dione (PDO) or bis-pyrimidyltetrazine (BMTZ) ligand on powdered MgO, Al.sub.2O.sub.3, or CeO.sub.2.

Claims

1. A single site catalyst system comprising: (a) a single site catalyst precursor compound and (b) a support, wherein the single site catalyst precursor comprises one or more of the formulae: ##STR00011## ##STR00012## wherein each X, independently, is a halide; and wherein n is 1-5 when present.

2. The single site catalyst system of claim 1, wherein the support is selected from the group consisting of powdered MgO, Al.sub.2O.sub.3, and CeO.sub.2.

3. The single site catalyst system of claim 2, wherein the support is MgO.

4. The single site catalyst system of claim 2, wherein the support is Al.sub.2O.sub.3.

5. The single site catalyst system of claim 2, wherein the support is CeO.sub.2.

6. A process comprising: (a) contacting a single site catalyst precursor comprising one or more of the formulae: ##STR00013## ##STR00014## wherein each X, independently, is a halide; and wherein n is 1-5 when present; (b) contacting the supported catalyst system, a vinyl terminated alkene and a hydrosilylation agent under hydrosilylation conditions; and (c) hydrosilylating the vinyl terminated alkene to form a hydrosilylated alkyl product.

7. The process of claim 6, wherein the support is selected from the group consisting of powdered MgO, Al.sub.2O.sub.3, and CeO.sub.2.

8. The process of claim 7, wherein the support is MgO.

9. The process of claim 7, wherein the support is Al.sub.2O.sub.3.

10. The process of claim 6, wherein the vinyl terminated alkene is 1-octene.

11. The process of claim 6, wherein the hydrosilylation agent comprises dimethoxymethylsilane.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 depicts structures of ligands: (a) 3,6-(2-pyridyl)-1,2,4,5-tetrazine (DPTZ), (b) 1,10-phenanthroline-5,6-dione (PDO), and (c) bis-pyrimidyltetrazine (BMTZ).

(2) FIG. 2 depicts fittings of Pt 4f XP spectra of Pt-PDO/CeO.sub.2: fresh catalyst (top), after 1 cycle of the reaction (mid), and after 3 cycles of the reaction (bottom). All spectra are normalized based on Ce 3d peak area so that the peak area reflects Pt concentration (Pt:Ce ratio) on the catalyst.

(3) FIG. 3 depicts fittings of Pt 4f XP spectra of fresh Pt-BMTZ/CeO.sub.2.

(4) FIG. 4 is an XP spectra of Pt-PDO/CeO.sub.2, Cl 2p region. Fresh catalyst (top), after 1 cycle of the reaction (mid), and after 3 cycles of the reaction (bottom). All spectra are normalized based on Pt 4f peak area so that peak size reflects the relative concentration of Cl with Pt (Cl:Pt ratio) on the catalyst.

(5) FIG. 5 is N 1s region. Fresh catalyst (top), after 1 cycle of the reaction (mid), and after 3 cycles of the reaction (bottom). All spectra are normalized based on Pt 4f peak area so that peak size reflects the relative concentration of N with Pt (N:Pt ratio) on the catalyst.

(6) FIG. 6 is an XP spectra of fresh Pt-BMTZ/CeO.sub.2, N is region.

(7) FIG. 7 is an XP spectra of fresh Pt-BMTZ/CeO.sub.2, Cl 2p region.

(8) FIG. 8 is a GC-MS spectrum from a post-reaction solution between 1 and 2, showing the formation of the desired product 3 and by-products. Numbers in the figure refer to compound numbers in Scheme 1. The concentration of main Si-containing by-products 4 and 5 is extremely low compared with the desired product 3, and no Markovnikov addition product was observed, showing high selectivity of the catalyst.

(9) FIG. 9 shows reusability test results of Pt-PDO/CeO.sub.2 for four hydrosilylation reaction cycles. Reaction conditions: T=70° C., t=30 min, 30 mg catalyst, 6 mmol 1, 5 mmol 2, and 3 mL toluene.

DETAILED DESCRIPTION

(10) In the specification and in the claims, the terms “including” and “comprising” are open-ended terms and should be interpreted to mean “including, but not limited to . . . .” These terms encompass the more restrictive terms “consisting essentially of” and “consisting of.”

(11) It must be noted that as used herein and in the appended claims, the singular forms “a”, “an”, and “the” include plural reference unless the context clearly dictates otherwise. As well, the terms “a” (or “an”), “one or more” and “at least one” can be used interchangeably herein. It is also to be noted that the terms “comprising”, “including”, “characterized by” and “having” can be used interchangeably.

(12) The term halide is known in the art and is intended to encompass chloride (Cl.sup.−), iodide (I.sup.−), fluoride (F.sup.−) and bromide (BP).

(13) In chemical formulae presented herein, it should be understood that the use of solid line or a dashed line between a heteroatom, e.g., N or O, and a platinum center indicates that there is a physical association between the heteroatom and the metal, typically considered a coordinative or dative bond. It does not necessarily imply that a covalent bond is present.

(14) Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art to which this invention belongs. All publications and patents specifically mentioned herein are incorporated by reference in their entirety for all purposes including describing and disclosing the chemicals, instruments, statistical analyses and methodologies which are reported in the publications which might be used in connection with the invention. All references cited in this specification are to be taken as indicative of the level of skill in the art. Nothing herein is to be construed as an admission that the invention is not entitled to antedate such disclosure by virtue of prior invention.

(15) Two new supported Pt hydrosilylation catalysts with a bidentate N-based ligands 1,10-Phenanthroline-5,6-Dione (PDO) and bis-pyrimidyltetrazine (BMTZ) are disclosed. The Pt-PDO/CeO.sub.2 and Pt-BMTZ/CeO.sub.2 catalysts are created through a metal-ligand self-assembly strategy, and principally contain highly dispersed Pt.sup.2+ sites. Both catalysts are active for alkene hydrosilylation under mild conditions with high selectivity, while Pt-PDO/CeO.sub.2 shows improved selectivity with an epoxy-containing substrate compared to Karstedt catalyst. The Pt-PDO/CeO.sub.2 catalyst also exhibits excellent reusability: the activity is steady through four reaction cycles and Pt leaching is significantly mitigated compared to Pt-DPTZ/CeO.sub.2. After reactions, Pt maintains similar coordination level with PDO, and is thus highly dispersed without noticeable aggregation. Cl partially leaves Pt, likely responsible for catalyst activation. A Pt.sup.(2+δ)+ species converted from Pt.sup.2+ is proposed to be the active species.

(16) The supported DPTZ ligand acts as a catalyst for hydrosilylation reactions. A catalyst is essential for this reaction. Current industrial production of silane materials relies on the Karstedt catalyst and the present invention shows some improvement over that catalyst with the new material described herein. Silane and silicon compounds are employed to enhance adhesion, increase mechanical properties of composites, improve dispersion of pigments and minerals, provide crosslinking, immobilize catalysts, and bind biomaterials.

(17) Catalysts are characterized by activity and selectivity. Activity refers to how much of the starting material in converted into a product material. Selectivity refers to the idea that a reaction might produce multiple products, but that it is usually desirable to obtain only one of those. The new catalyst material described herein outperforms the Karstedt catalyst in both activity and selectivity, thus there would be an improvement to the chemical production of silanes using this new material.

(18) It should be understood that the catalyst compounds are reaction products of a platinum precursor and an organic ligand, such as 1,10-Phenanthroline-5,6-Dione (PDO) or bis-pyrimidyltetrazine (BMTZ). Therefore, the resulting catalyst precursor can be a mixture of one or more active species. For example, the reaction between a platinum precursor and PDO can provide at least the following catalyst precursors and should not be limiting to one or more of the formulae:

(19) ##STR00001## ##STR00002## wherein each X, independently, is a halide; and wherein n is 1-5 when present, e.g., 1, 2, 3, 4 or 5.

(20) Oxide-supported Pt-DPTZ single-site catalysts (SSCs) are known..sup.52-53 These heterogeneous SSCs exhibit improvements over the commercial hydrosilylation catalyst (Karstedt catalyst) in selectivity, stability, and substrate scope. Nevertheless, their applications are challenged by low reusability due to active site leaching. Pt-DPTZ coordination through the bidentate N binding pockets (FIG. 1) is stable, but the binding between Pt-DPTZ complexes and supports is not..sup.53 Consequently, DPTZ has been replaced with other bidentate N-based ligands: 1,10-phenanthroline-5,6-dione (PDO, FIG. 1), and bis-pyrimidyltetrazine (BMTZ, FIG. 1). Both ligands have more functional groups offering stronger interaction with oxides than DPTZ. Not to be limited by theory, it is hypothesized that the replacement enhances interactions between Pt-ligand complexes and supports, so that active sites can be more effectively recycled.

(21) The Pt-PDO/CeO.sub.2 catalyst was synthesized using the one-step impregnation method reported previously,.sup.52 as described above. In short, H.sub.2PtCl.sub.6.6H.sub.2O solution was added dropwise to pre-mixed PDO solution (water as solvent) and CeO.sub.2, followed by stirring, water evaporation, and rinsing (see the experimental section for details). CeO.sub.2 was selected as the support because in previous studies, it created catalysts with higher activity and reusability than other oxides..sup.52-53 1 wt % Pt was added, and the actual Pt loading was determined by inductively coupled plasma mass spectrometry (ICP-MS) to be 0.47% (Table 1). On fresh Pt-PDO/CeO.sub.2, the Pt 4f.sub.7/2 X-ray photoelectron spectroscopy (XPS) peak is consistent with a single narrow Pt.sup.2+ component (binding energy=72.8 eV, full width at half maximum (FWHM)≈2.1 eV, FIG. 2 top). Therefore, Pt exists principally as dispersed Pt.sup.2+ cations, while metallic Pt nanoparticles are not present. This is expected because both bidentate N pockets and di-ketone pockets on PDO are suitable for Pt coordination, and the ligand has oxidizing potentials, stabilizing dispersed Pt.sup.2+. Previous evidence supported that a similar method creates predominantly Pt-DPTZ single-sites on CeO.sub.2..sup.52-53 On fresh Pt-PDO/CeO.sub.2, N (from PDO) and Cl (from H.sub.2PtCl.sub.6.6H.sub.2O) are clearly identified by XPS. N:Pt and Cl:Pt ratios are calculated based on XPS peak areas, and presented in Table 2. The sum of the two ratios on fresh Pt-PDO/CeO.sub.2 is 3.4, indicating Pt are highly coordinated with N, Cl. Considering Pt also coordinates with 0 from PDO and CeO.sub.2, Pt aggregates are not likely formed.

(22) The Pt-BMTZ/CeO.sub.2 catalyst was synthesized with a similar procedure with Pt-PDO/CeO.sub.2 (acetone as solvent). The final Pt wt % of the catalyst is 0.33% (Table 1). The Pt 4f.sub.712 XPS peak also shows a single Pt.sup.2+ component (binding energy=72.8 eV, FWHM≈2.6 eV, FIG. 3, suggesting most Pt are dispersed Pt.sup.2+ cations instead of metallic particles. Again, this is due to the favored coordination between bidentate N pockets and Pt, as well as the oxidizing potential of BMTZ. N (from the BMTZ) and Cl (from H.sub.2PtCl.sub.6.6H.sub.2O) are also clearly identified by XPS (FIG. 9), with the sum of N:Pt and Cl:Pt ratios being 6.6 (Table 2). In summary, XPS indicates that on both Pt-PDO/CeO.sub.2 and Pt-BMTZ/CeO.sub.2, Pt bind with the ligand, Cl, and O from CeO.sub.2, forming highly dispersed Pt.sup.2+ sites.

(23) TABLE-US-00001 TABLE 1 Pt:Ce ratios from XPS and Pt wt % from ICP, before and after reaction cycles. Pt-PDO/CeO.sub.2 After 1 After 3 reaction reaction Pt-BMTZ/CeO.sub.2 Fresh cycle cycles Fresh XPS Pt:Ce 0.101 0.098 0.070 0.048 XPS Pt 100 97 69 — recovery (%) ICP Pt wt % 0.47 — 0.29 0.33  ICP Pt 100 — 62 — recovery (%)

(24) TABLE-US-00002 TABLE 2 Summary of XPS results, before and after hydrosilylation reaction. Binding energy, full width of half maximum (FWHM), and atomic ratios. Pt-PDO/CeO.sub.2 After 1 After 3 reaction reaction Pt-BMTZ/CeO.sub.2 Fresh cycle cycles Fresh Pt 4f.sub.7/2 binding 72.8 72.7 72.9 72.8 energy (eV) Pt 4f FWHM 2.1 2.8 3.3 2.6 (eV) N:Pt 2.1 2.0 2.2 5.3 Cl:Pt 1.3 0.9 1.0 1.3

(25) Pt-PDO/CeO.sub.2 and Pt-BMTZ/CeO.sub.2 were tested as catalysts for a model hydrosilylation reaction between 1-octene (1) and dimethoxymethylsilane (2) shown in Scheme 1. Two reaction conditions were used: 70° C. for 30 min, and 60° C. for 20 min. The former was used to evaluate active site recyclability. The latter was for turnover number (TON) calculations and activity comparison as it keeps the conversion of 2 far below 100%. Both catalysts exhibited catalytic activity under both conditions, yielding anti-Markovnikov addition product 3 (see FIG. 8 for a representative GC-MS spectrum of the post-reactions solution). FIG. 8 also shows that alkene isomerization (forming 2-octene and 3-octene) and hydrogenation (forming octane) occurred. Therefore, all reactions were performed with 1.2 eq. 1. The most concentrated by-products from 2 were silane oligomers 4 and 5, the concentration of which was very low compared with 3 (FIG. 8). In addition, no Markovnikov addition product was observed, suggesting the catalysts are highly selective in this reaction. For the hydrosilylation of epoxy-containing alkene (Scheme 2), Pt-PDO/CeO.sub.2 showed improved selectivity (66%) over Karstedt catalyst (˜50%) at 100% silane conversion (80° C., 100 min),.sup.42, 53 which was similar with Pt-DPTZ/CeO.sub.2 (71%)..sup.53

(26) ##STR00003##

(27) ##STR00004##

(28) The reusability of Pt-PDO/CeO.sub.2 was examined by recycling it for 4 cycles of the reaction shown in Scheme 1, and results are shown in FIG. 9. After each reaction cycle, the catalyst was separated and put into a fresh batch of reaction solution for the next cycle. The conversion of 2 in all cycles was below 100%, and the selectivity remained similar with the first cycle. Pt-PDO/CeO.sub.2 showed excellent reusability, as its activity did not drop through 4 cycles (˜60% yield). In comparison, it has been shown that product yield decreases quickly on Pt-DPTZ/CeO.sub.2 once the conversion of 2 drops below 100%, due to active site leaching..sup.53 FIG. 9 strongly indicates that almost all active sites on Pt-PDO/CeO.sub.2 can be recycled effectively, which is an improvement over Pt-DPTZ/CeO.sub.2. Pt recovery percentage after the first reaction cycle was also much higher on Pt-PDO/CeO.sub.2 (97% XPS-based in Table 1) than Pt-DPTZ/CeO.sub.2 (62% XPS-based from previous studies). Activity of fresh Pt-PDO/CeO.sub.2 and Pt-BMTZ/CeO.sub.2 at 70° C., TON at 60° C. in the first 20 min, are presented and compared with Pt-DPTZ/CeO.sub.2 in Table 3. It was recognized that neither Pt-PDO/CeO.sub.2 nor Pt-BMTZ/CeO.sub.2 was not as active as Pt-DPTZ/CeO.sub.2, but for the case of Pt-PDO/CeO.sub.2, the TON difference is within 3-fold. In practice, one can compensate for lower activity by using more catalysts, but active site leaching is more challenging, especially for expensive noble metals. Therefore, from a practical perspective, significantly enhanced reusability is more desirable.

(29) TABLE-US-00003 TABLE 3 Activity of Pt-PDO/CeO.sub.2 and Pt-BMTZ/CeO.sub.2 compared with Pt-DPTZ/CeO.sub.2 Yield.sup.[a] Metal-Ligand (%) TON per Pt.sup.[b] Catalyst 70° C., 30 min 60° C., 20 min Pt-DPTZ .sup. 90.sup.[c] 6200 Pt-PDO 66 2700 Pt-BMTZ 24 1600 .sup.[a]Reaction condition: T = 70° C., t = 30 min, 30 mg catalyst, 6 mmol 1, 5 mmol 2, and 3 mL toluene. .sup.[b]Reaction condition: T = 60° C., t = 20 min, 15 mg catalyst, 3 mmol 1, 2.5 mmol 2, and 1.5 mL toluene. .sup.[c]Complete conversion of 2 was achieved in this reaction.

(30) The highly reusable Pt-PDO/CeO.sub.2 was characterized by XPS after the reaction in Scheme 1 to investigate its active sites. It was found that most, but not all, Pt was recyclable, with 97% Pt recovered after 1 cycle and 60-70% Pt recovered after 3 cycles (Table 1). ICP on post-reaction solution from the first reaction cycle showed Pt equivalent with <2% total Pt leaching, consistent with XPS results in Table 1. After the first reaction cycle, Table 2 shows that Pt 4f XPS peak widens (FWHM increased from 2.1 to 2.8) without significant shift in binding energy, indicating broader oxidation state distribution centered around +2 (FIG. 2, mid). Fitting (FIG. 2, Table 4) suggests two components were formed: Pt.sup.(2−δ)+ (˜72.2 eV) and Pt.sup.(2+δ)+ (˜73.7 eV). This implies that at least two different Pt species exist on fresh Pt-PDO/CeO.sub.2. Although both appear to be Pt.sup.2+, they evolve differently during catalysis, and hence the oxidation states vary after the reaction. After 3 cycles, the binding energy was still around 72.8 eV, and the peak further widens to FWHM=3.3 (Table 2). FIG. 2 (bottom) and Table 4 exhibit that the Pt.sup.(2+δ)+ component did not change much compared with after 1 reaction cycle, while the Pt.sup.(2−δ)+ component decreased obviously, indicating the Pt leaching (˜30% of total Pt) was mainly from the Pt.sup.(2−δ)+ species. However, the partial loss of P.sup.t(2−δ)+ had negligible impacts on the activity (FIG. 9), strongly implying that the Pt(.sup.2+δ)+ were the dominating active sites. It was demonstrated that although Pt leaching still occurred on Pt-PDO/CeO.sub.2, the actual active sites can be successfully recycled. It was noted that no metallic Pt was detected (FIG. 2), implying Pt remains highly dispersed. XPS also revealed that the N:Pt ratio remains constant through 3 cycles (Table 2, FIG. 9), and thus the Pt-PDO coordination is highly stable. In contrast, the Cl:Pt ratio drops (Table 2, FIG. 8), which is associated with the catalyst activation from previous studies on Pt-DPTZ/CeO.sub.2..sup.53

(31) TABLE-US-00004 TABLE 4 Changes in relative Pt concentrations of various oxidation states before and after hydrosilylation reactions on Pt-PDO/CeO.sub.2. Relative concentration.sup.[a] Catalyst status Pt.sup.(2−δ)+ Pt.sup.2+ Pt.sup.(2+δ)+ Total Pt Fresh 0 1 0 1 post-1rxn 0.54 0 0.43 0.97 post-3rxn 0.31 0 0.38 0.69 .sup.[a]Relative concentration of a Pt component on a sample was calculated based on the peak area from fittings (normalized to Ce 3d area of the same sample). For each catalyst, the total Pt 4f peak area of its fresh form was defined as 1.

(32) The following paragraphs enumerated consecutively from (1) through (55) provide for various aspects of the present invention. In one embodiment, in a first paragraph (1), the present invention provides a single site catalyst system comprising: (a) a single site catalyst precursor compound and (b) a support, wherein the single site catalyst precursor comprises one or more of the formulae:

(33) ##STR00005## ##STR00006## wherein each X, independently, is a halide; and wherein n is 1-5 when present, e.g., 1, 2, 3, 4, or 5.

(34) 2. The single site catalyst system of claim 1, wherein the support is selected from the group consisting of powdered MgO, Al.sub.2O.sub.3, and CeO.sub.2.

(35) 3. The single site catalyst system of claim 2, wherein the support is MgO.

(36) 4. The single site catalyst system of claim 2, wherein the support is Al.sub.2O.sub.3.

(37) 5. A process comprising: (a) contacting a single site catalyst precursor comprising one or more of the formulae:

(38) ##STR00007## ##STR00008## wherein each X, independently, is a halide; and wherein n is 1-5 when present, e.g., 1, 2, 3, 4 or 5; (b) contacting the supported catalyst system, a vinyl terminated alkene and a hydrosilylation agent under hydrosilylation conditions; and (c) hydrosilylating the vinyl terminated alkene to form a hydrosilylated alkyl product.

(39) 6. The process of claim 5, wherein the support is selected from the group consisting of powdered MgO, Al.sub.2O.sub.3, and CeO.sub.2.

(40) 7. The process of claim 6, wherein the support is MgO.

(41) 8. The process of claim 6, wherein the support is Al.sub.2O.sub.3.

(42) 9. The process of any of claims 5 through 8, wherein the vinyl terminated alkene is 1-octene

(43) 10. The process of any of claims 5 through 9, wherein the hydrosilylation agent comprises dimethoxymethylsilane.

(44) 11. A process comprising: (a) treating 1,10-phenanthroline-5,6-dione (PDO) with a support in a solvent to form a first mixture; (b) stirring the first mixture at room temperature for a period of time to form a second mixture; (c) treating the second mixture with H.sub.2PtCl.sub.6.6H.sub.2O to form a third mixture; and (d) drying the third mixture to remove the solvent to provide dried catalyst.

(45) 12. The process of claim 11, further comprising the step: (e) washing the dried catalyst with water; (f) washing the water washed catalyst of step (e) with dichloromethane (DCM) until all free 1,10-phenanthroline-5,6-dione (PDO) is removed to provide a supported catalyst.

(46) 13. The process of claim 11 or 12, wherein the support is selected from the group consisting of powdered MgO, Al.sub.2O.sub.3, and CeO.sub.2.

(47) 14. The process of claim 13, wherein the support is MgO.

(48) 15. The process of claim 13, wherein the support is Al.sub.2O.sub.3.

(49) 16. A process comprising: (a) contacting the supported catalyst system of any of claims 11 through 15, a vinyl terminated alkene and a hydrosilylation agent under hydrosilylation conditions; and (b) hydrosilylating the vinyl terminated alkene to form a hydrosilylated alkyl product.

(50) 17. The process of claim 16, wherein the vinyl terminated alkene is 1-octene

(51) 18. The process of either claim 16 or claim 17, wherein the hydrosilylation agent comprises dimethoxymethylsilane.

(52) 19. The single site catalyst system of claim 2, wherein the support is CeO.sub.2.

(53) 20. The process of claim 6, wherein the support is CeO.sub.2.

(54) 21. The process of claim 13, wherein the support is CeO.sub.2.

(55) 22. A single site catalyst system comprising: (a) a single site catalyst precursor compound and (b) a support, wherein the single site catalyst precursor comprises the formula:

(56) ##STR00009## wherein each X, independently, is a halide; and wherein n is 1 to 5, e.g., 1, 2, 3, 4, or 5.

(57) 23. The single site catalyst system of claim 22, wherein the support is selected from the group consisting of powdered MgO, Al.sub.2O.sub.3, and CeO.sub.2.

(58) 24. The single site catalyst system of claim 23, wherein the support is MgO.

(59) 25. The single site catalyst system of claim 23, wherein the support is Al.sub.2O.sub.3.

(60) 26. A process comprising: (a) contacting a single site catalyst precursor comprising the formula:

(61) ##STR00010## wherein each X, independently, is a halide; and wherein n is 1 to 5, e.g., 1, 2, 3, 4, or 5; (b) contacting the supported catalyst system, a vinyl terminated alkene and a hydrosilylation agent under hydrosilylation conditions; and (c) hydrosilylating the vinyl terminated alkene to form a hydrosilylated alkyl product.

(62) 27. The process of claim 26, wherein the support is selected from the group consisting of powdered MgO, Al.sub.2O.sub.3, and CeO.sub.2.

(63) 28. The process of claim 27, wherein the support is MgO.

(64) 29. The process of claim 27, wherein the support is Al.sub.2O.sub.3.

(65) 30. The process of any of claims 26 through 29, wherein the vinyl terminated alkene is 1-octene

(66) 31. The process of any of claims 26 through 30, wherein the hydrosilylation agent comprises dimethoxymethylsilane.

(67) 32. A process comprising: (a) treating bis-pyrimidyltetrazine (BMTZ) with a support in a solvent to form a first mixture; (b) stirring the first mixture at room temperature for a period of time to form a second mixture; (c) treating the second mixture with H.sub.2PtCl.sub.6.6H.sub.2O to form a third mixture; and (d) drying the third mixture to remove the solvent to provide dried catalyst.

(68) 33. The process of claim 32, further comprising the step: (e) washing the dried catalyst with water; (f) washing the water washed catalyst of step (e) with dichloromethane (DCM) until all free bis-pyrimidyltetrazine (BMTZ) is removed to provide a supported catalyst.

(69) 34. The process of claim 32 or 33, wherein the support is selected from the group consisting of powdered MgO, Al.sub.2O.sub.3, and CeO.sub.2.

(70) 35. The process of claim 34, wherein the support is MgO.

(71) 36. The process of claim 34, wherein the support is Al.sub.2O.sub.3.

(72) 37. A process comprising: (a) contacting the supported catalyst system of any of claims 32 through 36, a vinyl terminated alkene and a hydrosilylation agent under hydrosilylation conditions; and (b) hydrosilylating the vinyl terminated alkene to form a hydrosilylated alkyl product.

(73) 38. The process of claim 37, wherein the vinyl terminated alkene is 1-octene

(74) 39. The process of either claim 37 or claim 38, wherein the hydrosilylation agent comprises dimethoxymethylsilane.

(75) 40. The single site catalyst system of claim 23, wherein the support is CeO.sub.2.

(76) 41. The process of claim 27, wherein the support is CeO.sub.2.

(77) 42. The process of claim 35, wherein the support is CeO.sub.2.

(78) 43. A supported catalyst system comprising the reaction product of a platinum salt, an organic ligand comprising 1,10-phenanthroline-5,6-dione (PDO), wherein the platinum salt and organic ligand form a ligand/platinum catalyst precursor, and a support to provide the supported catalyst.

(79) 44. The supported catalyst system of claim 43, wherein the support is selected from the group consisting of powdered MgO, Al.sub.2O.sub.3, and CeO.sub.2.

(80) 45. The supported catalyst system of claim 44, wherein the support is MgO.

(81) 46. The supported catalyst system of claim 44, wherein the support is Al.sub.2O.sub.3.

(82) 47. The supported catalyst system of claim 44, wherein the support is CeO.sub.2.

(83) 48. A supported catalyst system comprising the reaction product of a platinum salt, an organic ligand comprising bis-pyrimidyltetrazine (BMTZ), wherein the platinum salt and organic ligand form a ligand/platinum catalyst precursor, and a support to provide the supported catalyst.

(84) 49. The supported catalyst system of claim 48, wherein the support is selected from the group consisting of powdered MgO, Al.sub.2O.sub.3, and CeO.sub.2.

(85) 50. The supported catalyst system of claim 49, wherein the support is MgO.

(86) 51. The supported catalyst system of claim 49, wherein the support is Al.sub.2O.sub.3.

(87) 52. The supported catalyst system of claim 49, wherein the support is CeO.sub.2.

(88) 53. A process comprising: (a) contacting a single site catalyst precursor comprising the supported catalyst system of any of claim 43 through 52 with a vinyl terminated alkene and a hydrosilylation agent under hydrosilylation conditions; and (b) hydrosilylating the vinyl terminated alkene to form a hydrosilylated alkyl product.

(89) 54. The process of claim 53, wherein the vinyl terminated alkene is 1-octene

(90) 55. The process of either claim 53 or claim 54, wherein the hydrosilylation agent comprises dimethoxymethylsilane.

EXAMPLES

(91) The invention will be further described with reference to the following non-limiting Examples. It will be apparent to those skilled in the art that many changes can be made in the embodiments described without departing from the scope of the present invention. Thus the scope of the present invention should not be limited to the embodiments described in this application, but only by embodiments described by the language of the claims and the equivalents of those embodiments. Unless otherwise indicated, all percentages are by weight.

(92) Synthesis of Pt-PDO/CeO.sub.2. 0.0096 g (0.046 mol) PDO (Sigma Aldrich, 98%) were dissolved in 25 mL H.sub.2O by stirring for 20 min at room temperature. 0.3 g CeO.sub.2 (BET surface area: 4.8 m.sup.2/g) were added to the yellow PDO solution and the mixture was then stirred for 2 h at room temperature. 0.0080 g H.sub.2PtCl.sub.6 6H.sub.2O (Alfa Aesar, 99.95% metal basis, 0.015 mol, 1 wt % by Pt with respect to total catalyst mass; 3 eq. PDO with Pt) were dissolved in 5 mL H.sub.2O. The Pt salt solution was then added to the CeO.sub.2/PDO/H.sub.2O mixture dropwise under stirring within 30 min. The mixture was covered and stirred for 24 h, then dried at room temperature under dry air flow overnight. The dried catalyst was washed with water, then dichloromethane (DCM) until all visible free PDO were removed. Pt-PDO/CeO.sub.2 catalyst is a light-yellow powder.

(93) Synthesis of Pt-BMTZ/CeO.sub.2. The synthesis of Pt-BMTZ/CeO.sub.2 followed a similar procedure with Pt-PDO/CeO.sub.2, with the following changes: PDO was replaced by BMTZ (synthesized by the group of Dr. Kenneth Caulton at Indiana University following a method reported in the literature).sup.68 of the same molar quantity (0.046 mol), and H.sub.2O was replaced by Acetone (Macron, 99%) of the same volume.

(94) General procedures for alkene hydrosilylation reactions. For 70° C., 30 min reactions: 30 mg supported Pt catalysts were weighed and kept in an empty reaction tube with cap. 5 mmol dimethoxymethylsilane (Alfa Aesar, >97%) and 6 mmol 1-octene (Alfa Aesar, >97%) were weighed into another reaction tube, and 3 mL toluene (Macron, ACS grade) was added to the same tube. For 60° C., 20 min reactions, the amount of all chemicals was reduced to half. Both tubes were pre-heated in a water bath at the reaction temperature for 10 min, before reactants and solvent were added into the tube with Pt catalysts. The tube was capped during the reaction to avoid evaporation of silane with low boiling point. After the reaction, the tube was cooled down quickly with cold water flow, the solid catalysts were centrifuged out for reuse or post-reaction characterizations, and the liquid mixture was diluted to 25 mL for GC-MS measurements with an Agilent 6890N Gas Chromatograph and 5973 Inert Mass Selective Detector. Product yield was calculated from its response intensity at m/z=203.2 with respect to the response of internal standard decane (Sigma Aldrich, >99%, ˜0.15 g added to all standard and post-reaction solutions) at m/z=142.2 using calibration curves pre-made with standard solutions. The product used to make standard solutions was purchased from Sigma Aldrich (≥95.0%). The calibration curve exhibits almost perfect linear relationship between normalized

(95) GC-MS response and concentration over the concentration range relevant to the experiments reported here. For all samples, the GC-MS response was measured from decane was within 20% of standard solutions used in the calibration curves. Epoxy-containing alkene substrate hydrosilylation reactions occurred under 80° C., 100 min conditions with 50 mg supported Pt catalyst weighed and kept in an empty reaction tube. 2.5 mmol trimethoxysilane (Sigma Aldrich, 95%) and 3 mmol 4-vinyl-1-cyclohexene 1,2-epoxide isomers (Sigma Aldrich, 98%) were weighed into another reaction tube, and 1.5 mL toluene (Macron, ACS grade) was added to the same tube.

(96) Catalyst characterization. X-ray photoelectron spectroscopy (XPS) measurements were performed with a PHI Versaprobe II XP spectrometer using a monochromated Al X-ray source. A small amount of each powder sample was fixed onto a platen with double-sided tape. XPS were collected at Pt 4f, N 1s, C 1s, Cl 2p, Ce 3d, and O is regions. A neutralizer was used to alleviate surface charging. The binding energy was corrected with adventitious C is peak (284.8 eV). Inductively coupled plasma mass spectrometry (ICP-MS) measurements were performed with an Agilent 7700 quadrupole ICP-MS instrument. Solid catalysts were treated with aqua regia to dissolve all Pt before measurement. For post-reaction solution samples, the solvent was evaporated first and then the residue was treated with aqua regia.

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(98) Although the present invention has been described with reference to preferred embodiments, persons skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. All references cited throughout the specification, including those in the background, are incorporated herein in their entirety. Those skilled in the art will recognize, or be able to ascertain, using no more than routine experimentation, many equivalents to specific embodiments of the invention described specifically herein. Such equivalents are intended to be encompassed in the scope of the following claims.