PRECIOUS METAL COMPLEXES WITH DIHYDROAZULENYL LIGANDS AND USE THEREOF

Abstract

The invention relates to a method for producing complexes of precious metals, in particular platinum, which have at least one organo-dihydroazulenyl ligand. The invention also relates to complexes of precious metals, in particular platinum, which have at least one organo-dihydroazulenyl ligand and to the use of the aforementioned metal complexes as precatalysts or catalysts in a chemical reaction or as precursor compounds for producing a layer which contains a precious metal, in particular platinum, or a metal layer consisting of a precious metal, in particular platinum, in particular on at least one surface of a substrate. The invention additionally relates to a substrate, in particular a substrate which can be obtained according to such a method. The invention also relates to a crosslinkable silicon composition comprising at least one compound with aliphatic carbon-carbon multi-bonds, at least one compound with Si-bonded hydrogen atoms, and at least one platinum (IV) complex of the aforementioned type. The invention also relates to novel alkali metal organo-dihydroazulenyls which can be used to produce metal complexes, in particular of the aforementioned type.

Claims

1. Compound according to general formula ##STR00036## wherein M.sup.+ is an alkali metal cation, R is selected from the group consisting of primary, secondary, tertiary alkyl, alkenyl and alkynyl radicals having 1 to 10 carbon atoms, cyclic alkyl radicals having 3 to 10 carbon atoms, a benzyl radical, mononuclear aryl radicals, polynuclear aryl radicals, mononuclear heteroaryl radicals and polynuclear heteroaryl radicals, Y is a neutral ligand that is bound or coordinated to M.sup.+ via at least one donor atom, wherein H.sub.2O is excluded, and n=0, 1, 2, 3 or 4, wherein the compounds lithium-7-iso-propyl-1,4,8-trimethyl-dihydroazulenide and lithium-7-iso-propyl-1,4-dimethyl-8-phenyl-dihydroazulenide and their THE adducts and DME adducts are excluded.

2. Compound according to claim 1, wherein i. there is an isomerically pure compound according to general formula I or general formula II or ii. there is an isomer mixture containing a first regioisomer according to formula I and a second regioisomer according to formula II.

3. Compound according to claim 2, wherein an isomer ratio of first regioisomer: second regioisomer is ?80:20 and <90:10.

4. Compound according to claim 1, wherein the alkali metal cation M.sup.+ is selected from the group consisting of Li.sup.+, Na.sup.+ and K.sup.+.

5. Compound according to claim 1, wherein the neutral ligand Y A) is a polar aprotic solvent or B) is a crown ether selected from the group consisting of macrocyclic polyethers and aza-, phospha- and thia-derivatives thereof, wherein an internal diameter of the crown ether and an ion radius of the alkali metal cation M.sup.+ correspond to each other.

6. Use of a compound according to general formula I and/or according to general formula II according to claim 1 for producing a platinum(IV) complex according to general formula ##STR00037## wherein R is selected from the group consisting of primary, secondary, tertiary alkyl, alkenyl and alkynyl radicals having 1 to 10 carbon atoms, cyclic alkyl radicals having 3 to 10 carbon atoms, a benzyl radical, mononuclear aryl radicals, polynuclear aryl radicals, mononuclear heteroaryl radicals and polynuclear heteroaryl radicals.

7. Method for producing a platinum(IV) complex according to general formula ##STR00038## wherein R is selected from the group consisting of primary, secondary, tertiary alkyl, alkenyl and alkynyl radicals having 1 to 10 carbon atoms, cyclic alkyl radicals having 3 to 10 carbon atoms, a benzyl radical, mononuclear aryl radicals, polynuclear aryl radicals, mononuclear heteroaryl radicals and polynuclear heteroaryl radicals, using a compound according to the general formula I and/or general formula II according to claim 1, comprising the steps of: A. providing the compound according to general formula I and/or general formula II and a platinum precursor, B. synthesizing the platinum(IV) complex according to general formula III and/or general formula IV using the compound according to general formula I and/or general formula II as a reactant in a solvent S.sub.P, C. optionally isolating the platinum(IV) complex synthesized in step B according to general formula III and/or general formula IV.

8. Method according to claim 7, wherein the solvent S.sub.P comprises at least one solvent selected from the group consisting of polar aprotic solvents, aliphatic hydrocarbons, aromatic hydrocarbons, organosilicon compounds, and mixtures thereof.

9. Method according to claim 7, wherein the synthesis in step B comprises at least one salt metathesis reaction.

10. Method according to claim 7, wherein the platinum precursor to be provided in step A. is selected from the group consisting of trimethylplatinum(IV) iodide, trimethylplatinum(IV) bromide and trimethylplatinum(IV) chloride, and mixtures thereof, wherein provision takes place i. as a solution comprising the platinum precursor and a solvent SA or ii. as a solid.

11. Platinum(IV) complex according to general formula ##STR00039## or solution or suspension comprising a platinum(IV) complex according to general formula ##STR00040## and a solvent that is in particular miscible with or identical to the solvent S.sub.P, wherein R is selected from the group consisting of primary, secondary, tertiary alkyl, alkenyl and alkynyl radicals having 1 to 10 carbon atoms, cyclic alkyl radicals having 3 to 10 carbon atoms, a benzyl radical, mononuclear aryl radicals, polynuclear aryl radicals, mononuclear heteroaryl radicals and polynuclear heteroaryl radicals, obtained or obtainable according to a method according to claim 7.

12. Platinum(JV) complex according to general formula ##STR00041## or solution or suspension comprising a platinum(IV) complex according to general formula ##STR00042## and a solvent, wherein R is selected from the group consisting of primary, secondary, tertiary alkyl, alkenyl and alkynyl radicals having 1 to 10 carbon atoms, cyclic alkyl radicals having 3 to 10 carbon atoms, a benzyl radical, mononuclear aryl radicals, polynuclear aryl radicals, mononuclear heteroaryl radicals and polynuclear heteroaryl radicals.

13. Platinum(IV) complex or solution or suspension according to claim 11, wherein there is a diastereomer mixture comprising a first diastereomer according to formula III.D1 and a second diastereomer according to formula III.D2, ##STR00043## and/or a third diastereomer according to formula IV.D3 and a fourth diastereomer according to formula IV.D4, ##STR00044## wherein each diastereomer is present as an enantiomer mixture.

14. The platinum(IV) complex or solution or suspension according to claim 11, wherein at least one diastereomer is present as a racemate.

15. Platinum(IV) complex or solution or suspension according to claim 13, wherein there is a mixture of two diastereomers and wherein a diastereomeric ratio of first diastereomer: second diastereomer or third diastereomer: fourth diastereomer is ?60:40 and <90:10.

16. Platinum(IV) complex or solution or suspension according to claim 13, wherein there is a diastereomer mixture consisting of the first diastereomer according to formula III.D1 and the second diastereomer according to formula III.D2, ##STR00045## wherein each diastereomer is present as an enantiomer mixture.

17. Platinum(IV) complex according to formula ##STR00046## or solution or suspension comprising a platinum(IV) complex according to formula V and/or formula VI and a solvent SD that comprises or is a nonpolar aprotic or a polar aprotic solvent.

18. Use of at least one platinum(IV) complex according to claim 11, as i. a precatalyst or a solution or suspension containing a precatalyst in a chemical reaction and/or ii. a catalyst or a solution or suspension containing a catalyst in a chemical reaction and/or iii. a precursor compound or a solution or suspension containing a precursor compound for producing at least one layer consisting of platinum or at least one layer containing platinum on at least one surface of a substrate.

19. Method for carrying out a chemical reaction using at least one platinum(IV) complex according to claim 11, comprising the steps of: A) providing the at least one platinum(IV) complex according to general formula III and/or IV and/or according to formula V and/or VI or the at least one solution or suspension, comprising a platinum(IV) complex according to general formula III and/or IV and a solvent that is in particular miscible with or identical to the solvent S.sub.P, and/or comprising a platinum(IV) complex according to formula V and/or VI and a solvent SD that comprises or is a nonpolar aprotic or a polar aprotic solvent, and B) carrying out the chemical reaction using the at least one platinum(IV) complex as a precatalyst and/or as a catalyst.

20. Method for producing i. at least one layer consisting of platinum or ii. at least one layer containing platinum on at least one surface of a substrate using at least one platinum(IV) complex according to claim 11, comprising the steps of: A) providing the at least one platinum(IV) complex according to general formula III and/or IV or the at least one solution or suspension, comprising a platinum(IV) complex according to general formula III and/or IV and a solvent that is in particular miscible with or identical to the solvent S.sub.P and B) depositing i. the at least one layer consisting of platinum or ii. the at least one layer containing platinum on the at least one surface of the substrate using the at least one platinum(IV) complex according to general formula III and/or IV as precursor compound.

21. Substrate comprising i. at least one layer consisting of platinum or ii. at least one layer containing platinum on at least one surface, wherein the at least one layer consisting of platinum or the at least one layer containing platinum is producible or produced using at least one platinum(IV) complex according to claim 11.

22. Crosslinkable silicone composition comprising i. at least one compound selected from the group consisting of type (a) compounds, type (b) compounds and type (c) compounds, wherein type (a) compounds are organic compounds and organosilicon compounds, each comprising at least two radicals having aliphatic carbon-carbon multi-bonds, type (b) compounds are organosilicon compounds, each comprising at least two Si-bonded hydrogen atoms, and type (c) compounds are organosilicon compounds, each comprising SiC-bonded radicals having aliphatic carbon-carbon multi-bonds and Si-bonded hydrogen atoms, wherein the silicone composition contains at least one compound having aliphatic carbon-carbon multi-bonds and at least one compound having Si-bonded hydrogen atoms, and ii. at least one platinum(IV) complex according to claim 11.

23. Compound according to claim 1, wherein R=Me.

Description

[0371] Other characteristics, details, and advantages of the invention follow from the exact wording of the claims, as well as from the following description of the embodiment examples based upon the illustrations. In the figures:

[0372] FIG. 1 shows a diagram relating to the conversion of the hydrosilylation reaction of 1-octene with pentamethyldisiloxane using 5 ppm of [PtMe.sub.3(GuaMe)] (triangles) or 5 ppm of [PtMe.sub.3(CpMe)] (squares) as a precatalyst,

[0373] FIG. 2 shows UV/VIS spectrum of [PtMe.sub.3(GuaMe)], taken up in cyclohexane (10.sup.?5 mol/L).

[0374] During the hydrosilylation reaction of 1-octene with pentamethyldisiloxane using 5 ppm of [PtMe.sub.3(GuaMe)] as a precatalyst (see example 4, NMR experiments with 5 ppm of Pt), .sup.1H-NMR spectra (C.sub.6D.sub.6, 298 K, 300 MHz) were recorded at predefined time intervals. A first .sup.1H-NMR spectrum was recorded at time 0 h, i.e., before starting the hydrosilylation reaction. After about 0.25 h, 0.5 h, 1 h, 2 h, 4 h, 8 h and 24 h, further .sup.1H-NMR spectra were recorded.

[0375] The reaction equation for the hydrosilylation of 1-octene is as follows:

##STR00033##

[0376] The conversion was in each case based on the CH.sub.2 group of the product (highlighted in gray in the product molecule) with a shift of 0.60 ppm. All .sup.1H-NMR spectra were taken into account in the calculation of the conversions. Table 1 shows the calculated conversions of the hydrosilylation reaction of 1-octene with pentamethyldisiloxane using 5 ppm of [PtMe.sub.3(GuaMe)] as a precatalyst (see column 2). Under identical conditions, the hydrosilylation reaction of 1-octene with pentamethyldisiloxane was carried out using 5 ppm of [PtMe.sub.3(CpMe)]. The calculated conversions are also indicated in Table 1 (see column 3).

TABLE-US-00001 TABLE 1 Conversion in % Time in h [PtMe.sub.3(GuaMe)] [PtMe.sub.3(CpMe)] 0 0 0 0.25 96.7 30.1 0.5 98.2 37.7 1 100 42.7 2 100 60.2 4 100 85.4 8 100 98.3 24 100 99.7

[0377] The graphical evaluation of the results listed in Table 1 is shown in FIG. 1. The time in hours (h) is plotted on the abscissa and the conversion in percent (%) is plotted on the ordinate. The triangular data points indicate the conversions calculated as a precatalyst when using [PtMe.sub.3(GuaMe)]. The square data points indicate the calculated conversions that were achieved with [PtMe.sub.3(CpMe)] as a precatalyst.

[0378] It can be seen that the hydrosilylation reaction using 5 ppm of [PtMe.sub.3(GuaMe)] is already almost complete after approximately 1 h. Consequently, a very satisfactory reaction rate is achieved that, under identical conditions, is in particular higher than that of the Pt(IV) complex [PtMe.sub.3(CpMe)] known as a hydrosilylation catalyst. In other words: The precatalyst [PtMe.sub.3(GuaMe)] has a higher activity than [PtMe.sub.3(CpMe)].

[0379] Advantageously, the Pt(IV) compound [PtMe.sub.3(GuaMe)] is present as a liquid and exhibits absorption in the visible range. The UV/VIS spectrum of [PtMe.sub.3(GuaMe)] is shown in FIG. 2. The wavelength in nm is plotted on the abscissa and the absorption is plotted in arbitrary units (a. u.) on the ordinate. A shoulder is observed at >340 nm. This is caused by the two olefinic double bonds of the seven-membered ring, which are conjugated with the aromatic system of the five-membered ring. Contamination by neutral guaiazulene, optionally formed by abstraction of an H atom in the 8 position of the dihydroguaiazulenide ligand, is not detectable in the visible range (blue-green) of the spectrum shown in FIG. 2.

[0380] The fact that the complex [PtMe.sub.3(GuaMe)] exhibits absorption in the visible range is a further advantage of this Pt(IV) compound used here as a precatalyst. This is because, in the case of light-induced platinum-catalyzed hydrosilylation reactions, the use of UV/VIS light is regularly provided, as a result of which special safety measures are usually required in order to reduce the risk of skin cancer. Such safety measures are not absolutely necessary when [PtMe.sub.3(GuaMe)] is used.

[0381] According to conventional wisdom, photolysis of a known precatalyst comprising a cyclopentadienyl anion, for example [PtMe.sub.3(Cp)] and [PtMe.sub.3(CpMe)], in the presence of a silane, for example pentamethyldisiloxane, results in the formation of a platinum colloid as an active hydrosilylation catalyst. (L. D. Boardman, Organometallics 1992, 11, 4194-4201) For the hydrosilylation reaction of 1-octene with pentamethyldisiloxane (equimolar mixture), Boardman specifies a precatalyst concentration of 10 ppm of platinum as [PtMe.sub.3(Cp)].

[0382] When using the precatalyst [PtMe.sub.3(GuaMe)] shown for the first time in the context of the present invention, a complete conversion of the substrates 1-octene and pentamethyldisiloxane is already observed, namely already after about 1 h, at 50% of the catalyst concentration selected in the literature, i.e., at a precatalyst concentration of 5 ppm of platinum as [PtMe.sub.3(GuaMe)].

[0383] A further advantage of the compound [PtMe.sub.3(GuaMe)] used in the present case as a precatalyst over Pt(IV) compounds containing cyclopentadienyl anions is that the guaiazulene required for the production thereof is synthesized using renewable raw materials instead of crude oil. As a result, the preparation of the Pt(IV) complex [PtMe.sub.3(GuaMe)] can be realized in a comparatively sustainable, simple and cost-effective manner.

[0384] Consequently, the semi-sandwich complex [PtMe.sub.3(GuaMe)] used in the context of the present invention for the hydrosilylation reaction of 1-octene with pentamethyldisiloxane is a relatively sustainable and cost-effective alternative to known hydrosilylation precatalysts such as [PtMe.sub.3(Cp)] and [PtMe.sub.3(CpMe)].

Protocols for the Synthesis of Li(GuaMe) and [PtMe.SUB.3.(GuaMe)]

[0385] (GuaMe).sup.?=C.sub.15H.sub.19.sup.? [0386] =7-iso-propyl-1,4-dimethyl-8-methyl-dihydroazulenyl-anion (Gua-8-Me).sup.1? or [0387] 7-iso-propyl-1,4-dimethyl-6-methyl-dihydroazulenyl-anion (Gua-6-Me).sup.1?

Materials and Methods

[0388] All reactions were carried out under standard inert gas conditions. The solvents and reagents used were purified and dried according to standard procedures.

[0389] All nuclear magnetic resonance spectroscopic measurements were carried out on a Bruker AV II 300, Bruker AV II HD 300, DRX 400 or AV III 500 device. .sup.13C-NMR spectra were measured in a standard .sup.1H broadband decoupled manner at 300 K. .sup.1H and .sup.13C-NMR spectra were calibrated to the corresponding residual proton signal of the solvent as an internal standard: .sup.1H: DMSO[d.sub.6]: 2.50 ppm, C.sub.6D.sub.6: 7.16 ppm (s); .sup.13C: DMSO[d.sub.6]: 39.52 ppm; C.sub.6D.sub.6: 128.0 ppm (t). The chemical shifts are indicated in ppm and refer to the ? scale. All signals are provided with the following abbreviations according to their splitting pattern: s (singlet), d (doublet), dd (double doublet), q (quartet) or sept (septet).

[0390] High-resolution LIFDI mass spectra were obtained using an AccuTOF-GCv-TOF mass spectrometer (JEOL).

[0391] UV/VIS spectra were recorded with an Avantes AvaSpec-2048 spectrophotometer in 10 mm cuvettes in cyclohexane at 10 ?M concentrations at a scan rate of 600 nm/min at room temperature.

[0392] Thermogravimetric studies were performed with a DSC-TGA 3 (Mettler Toledo) in a glove box. The samples were heated in aluminum crucibles at a heating rate of 10 K/min to the final temperature. The decomposition temperatures were determined using the data from the DSC TGA. The evaluation of the spectra obtained was carried out with STARe software made by Mettler Toledo.

Example 1: Preparation of Li(GuaMe)

[0393] The Li(GuaMe) reactant was determined on the basis of the synthesis described by Edelmann and his collaborators for lithium-7-iso-propyl-1,4,8-trimethyl-dihydroguaiazulenide (J. Richter, P. Liebing, F. T. Edelmann, Inorg. Chim. Acta 2018, 475, 18-27):

##STR00034##

[0394] Guaiazulene (4.00 g, 20.2 mmol) in 40 mL diethyl ether was admixed with MeLi (1.59 M in diethyl ether, 12.68 mL) at 0? C. The mixture was warmed to room temperature and stirred for a further 12 h. During this time, the blue color disappeared and a brown suspension formed. The precipitated product was isolated by filtration, washed with diethyl ether (3?20 mL) and dried in vacuo to give Li(GuaMe) as an off-white, highly air- and moisture-sensitive solid (3.35 g, 15.2 mmol, 75%).

[0395] .sup.1H-NMR (300.1 MHz, DMSO-d.sub.6): ??=5.42 (d, .sup.3J.sub.HH=3.5 Hz, 1H), 5.37 (d, .sup.3J.sub.HH=3.5 Hz, 1H), 5.33 (d, .sup.3J.sub.HH=7.0 Hz, 1H), 4.84 (d, .sup.3J.sub.HH=6.8 Hz, 1H), 3.41 (q, .sup.3J.sub.HH=7.2 Hz, 1H), 2.34 (sept, .sup.3J.sub.HH=6.7 Hz, 1H), 2.02 (s, 3H), 1.99 (s, 3H), 1.04 (d, .sup.3J.sub.HH=6.7 Hz, 3H), 1.00 (d, .sup.3J.sub.HH=6.7 Hz, 3H), 0.70 (d, .sup.3J.sub.HH=6.9 Hz, 3H) ppm; .sup.13C-NMR (300.1 MHz, DMSO-d.sub.6): ?=140.1 (s, 1C), 135.4 (s, 1C), 121.3 (s, 1C), 120.3 (s, 1C), 117.7 (s, 1C), 108.7 (s, 1C), 106.4 (s, 1C), 106.2 (s, 1C), 100.6 (s, 1C), 37.0 (s, 1C), 33.5 (s, 1C), 24.2 (s, 1C), 23.2 (s, 1C), 22.7 (s, 1C), 20.0 (s, 1C), 13.9 (s, 1C).

Note:

[0396] The Li(GuaMe) compound was obtained as a mixture of the two regioisomers lithium-7-iso-propyl-1,4,8-trimethyl-dihydroguaiazulenide (Li(Gua-8-Me)) and lithium-7-iso-propyl-1,4,6-trimethyl-dihydroguaiazulenide (Li(Gua-6-Me)). According to .sup.1H-NMR spectroscopic analysis, the isolated isomer mixture consisted of 12 mol % to 15 mol % of Li(Gua-6-Me) and 85 mol % to 88 mol % of Li(Gua-8-Me).

Example 2: Preparation of [PtMe.SUB.3.(GuaMe)]

[0397] ##STR00035##

[0398] Li(GuaMe) (243 mg, 1.10 mmol) and [PtMe.sub.3l].sub.4 (405 mg, 0.28 mmol) were suspended in diethyl ether (20 mL), and the suspension was stirred at 40? C. for 30 min, then at room temperature for 4 h. A yellow solution was obtained. The solvent was removed in vacuo. The oily residue was taken up in pentane (40 mL), and inorganic salts and any unreacted reactants were separated off by filtration. The solvent of the filtrate was removed in vacuo, and [PtMe.sub.3(GuaMe)] was obtained as a yellow green oil in a good yield (386 mg, 0.85 mmol, 77%). The .sup.1H-NMR spectrum shows a d.r. of 68% (main diastereomer, fraction 2): 32% (secondary diastereomer, fraction 1). The compound can be condensed, for example, onto a sublimation finger (acetone/dry ice, ?78? C.). The product can be further purified by means of column chromatography (silica or Al.sub.2O.sub.3 (neutral), hexane).

[0399] Fraction 1 ([PtMe.sub.3(Gua-8-endo-Me)], secondary diastereomer): .sup.1H-NMR (300.1 MHz, DMSO-d.sub.6): ?=6.03 (dd, .sup.3J.sub.HH=2.8 Hz, 1H), 5.48 (d, .sup.3J.sub.HH=7.1 Hz, 1H), 5.43 (d, .sup.3J.sub.HH=2.7 Hz, 1H), 5.38 (d, .sup.3J.sub.HH=2.6 Hz, 1H), 3.17 (q, .sup.3J.sub.HH=6.8 Hz, 1H), 2.28 (sept, .sup.3J.sub.HH=5.4 Hz, 1H), 1.93 (s, 3H), 1.92 (s, 3H), 1.03 (d, .sup.3J.sub.HH=2.5 Hz, 3H), 1.01 (d, .sup.3J.sub.HH=2.3 Hz, 3H), 0.58 (s, .sup.2J.sub.PtH=40.6 Hz, 9H) ppm; .sup.13C-NMR (300.1 MHz, DMSO-d.sub.6): ?=149.0 (s, 1C), 126.9 (s, 1C), 123.5 (s, 1C), 118.1 (s, 1C), 116.6 (s, 1C), 110.1 (s, 1C), 109.3 (s, 1C), 92.4 (s, 1C), 86.1 (s, 1C), 36.8 (s, 1C), 31.5 (s, 1C), 22.7 (s, 1C), 21.9 (s, 1C), 21.6 (s, 1C), 19.4 (s, 1C), 9.5 (s, 1C), ?13.4 (s, .sup.1J.sub.PtC=359 Hz, 3C).

[0400] Fraction 2 ([PtMe.sub.3(Gua-8-exo-Me)], main diastereomer): .sup.1H-NMR (300.1 MHz, DMSO-d.sub.6): ?=6.06 (dd, .sup.3J.sub.HH=2.6 Hz, 1H), 5.51 (d, .sup.3J.sub.HH=6.7 Hz, 1H), 5.48 (d, .sup.3J.sub.HH=2.6 Hz, 1H), 5.28 (d, .sup.3J.sub.HH=2.6 Hz, 1H), 3.36 (q, .sup.3J.sub.HH=7.0 Hz, 1H), 2.39 (sept, .sup.3J.sub.HH=6.5 Hz, 1H), 1.98 (s, 3H), 1.92 (s, 3H), 1.02 (d, .sup.3J.sub.HH=2.6 Hz, 3H), 0.99 (d, .sup.3J.sub.HH=1.9 Hz, 3H), 0.80 (s, .sup.2J.sub.PtH=40.3 Hz, 9H) ppm; .sup.13C-NMR (300.1 MHz, DMSO-d.sub.6): ?=150.8 (s, 1C), 128.9 (s, 1C), 124.9 (s, 1C), 120.0 (s, 1C), 117.9 (s, 1C), 109.9 (s, 1C), 108.7 (s, 1C), 91.3 (s, 1C), 83.2 (s, 1C), 36.4 (s, 1C), 30.9 (s, 1C), 21.7 (s, 1C), 21.6 (s, 1C), 21.5 (s, 1C), 20.2 (s, 1C), 10.1 (s, 1C), ?15.28 (s, .sup.1J.sub.PtC=359 Hz, 3C).

[0401] TGA (T.sub.S=25 K, T.sub.E=600 K, 10 K/min): Stages: 1, 3% degradation: 180.0? C., total mass degradation: 50.7%.

Note:

[0402] The diastereomers that can be prepared starting from lithium-7-iso-propyl-1,4,6-trimethyl-dihydroguaiazulenide Li(Gua-6-Me) can neither be detected nor isolated by means of .sup.1H-NMR spectroscopy. Only thin-layer chromatography provides indications of the four possible diastereomers [PtMe.sub.3(Gua-6-endo-Me)], [PtMe.sub.3(Gua-6-exo-Me)], [PtMe.sub.3(Gua-8-endo-Me)] and [PtMe.sub.3(Gua-8-exo-Me)].

Example 3: Preparation of a) [PtMe.SUB.3.(Gua-8-Me)-CH.SUB.2.-(Gua-6-Me)PtMe.SUB.3.] and b) [PtMe.SUB.3.(Gua-8-Me)-CH.SUB.2.-(Gua-8-Me)PtMe.SUB.3.]

[0403] Li(GuaMe) (243 mg, 1.10 mmol) and [PtMe.sub.3l].sub.4 (405 mg, 0.28 mmol) were suspended in diethyl ether (20 mL), and the suspension was stirred at 40? C. for 30 min, then at room temperature for 4 h. A yellow solution was obtained. The solvent was removed in vacuo. The oily residue was taken up in pentane (40 mL), and inorganic salts and any unreacted reactants were separated off by filtration. The solvent of the filtrate was removed in vacuo, and [PtMe.sub.3(GuaMe)] was obtained as a yellow green oil in a good yield (386 mg, 0.85 mmol, 77%).

[0404] The .sup.1H-NMR spectrum of the yellow green oil in DMSO-d.sub.6 (for the evaluation see Example 2) shows a d.r. of 68% ([PtMe.sub.3(Gua-8-exo-Me)]): 32% (PtMe.sub.3(Gua-8-endo-Me)]). The two diastereomers [PtMe.sub.3(Gua-6-endo-Me)] and [PtMe.sub.3(Gua-6-exo-Me)] cannot be detected by means of .sup.1H-NMR spectroscopy.

a) [PtMe.sub.3(Gua-8-Me)-CH.sub.2-(Gua-6-Me)PtMe.sub.3]

[0405] The sample examined by means of .sup.1H-NMR spectroscopy was stored for three days under daylight irradiation at room temperature.

[0406] As a result, crystals of the dimeric compound [PtMe.sub.3(Gua-8-Me)-CH.sub.2-(Gua-6-Me)PtMe.sub.3] suitable for X-ray structure analysis were obtained. In addition, a toluene solution of a crystal was analyzed by means of mass spectrometry. A high resolution of a LIFDI (FD+) spectrum shows the associated peak at m/z=890.36474 (m/z calculated for [C.sub.37H.sub.56Pt.sub.2].sup.+: 890.36775), namely in accordance with the calculated isotope pattern.

b) [PtMe.sub.3(Gua-8-Me)-CH.sub.2-(Gua-8-Me)PtMe.sub.3]

[0407] The yellow green oil was subjected to sublimation (acetone/dry ice, ?78? C.) and column chromatography (silica or Al.sub.2O.sub.3 (neutral), hexane). A sample of the isolated diastereomer mixture consisting of [PtMe.sub.3(Gua-8-exo-Me)] and [PtMe.sub.3(Gua-8-endo-Me)] was dissolved in DMSO. The solution was stored at room temperature for three days under daylight irradiation.

[0408] An LIFDI (FD+) spectrum (in toluene) of a sample of the DMSO solution shows a peak at m/z=890.35 (m/z calculated for [C.sub.37H.sub.56Pt.sub.2]+: 890.36775) and serves as evidence for the formation of [PtMe.sub.3(Gua-8-Me)-CH.sub.2-(Gua-8-Me)PtMe.sub.3].

Example 4: Photohydrosilylation of 1-Octene with Pentamethyldisiloxane Using [PtMe.SUB.3.(GuaMe)] as a Precatalyst

NMR Experiments with 5 ppm of Pt:

Stock Solution (1.78 M):

[0409] 500 mg of 1-octene (4.45 mmol), 661 mg of pentamethyldisiloxane (4.45 mmol), 2.5 mL of C.sub.6D.sub.6

[0410] Pt complex solution (0.0889 mM=0.0005 mol % compared to stock solution): 0.403 mg of [PtMe.sub.3(GuaMe)] (see Example 2), 5 mL of C.sub.6D.sub.6

[0411] 0.25 mL of stock solution and 0.25 mL of Pt complex solution were filled into an NMR tube. The tube was shaken and then irradiated with UV light (Osram Ultra Vitalux, 300 W, 220 V, plant lamp) for 5 min. .sup.1H-NMR spectra were recorded at time 0 h and after about 0.25 h, 0.50 h, 1 h, 2 h, 4 h, 8 h and 24 h.

[0412] The invention is not limited to one of the embodiments described above but may be modified in many ways.

[0413] It can be seen that the invention relates to a method for producing complexes of precious metals, in particular platinum, which have at least one organo-dihydroazulenyl ligand. The invention also relates to complexes of precious metals, in particular platinum, which have at least one organo-dihydroazulenyl ligand and to the use of the aforementioned metal complexes as precatalysts and/or catalysts in a chemical reaction or as precursor compounds for producing a layer which contains a precious metal, in particular platinum, or a metal layer consisting of a precious metal, in particular platinum, in particular on at least one surface of a substrate. The invention additionally relates to a substrate, in particular a substrate which can be obtained according to such a method. The invention also relates to a crosslinkable silicon composition comprising at least one compound with aliphatic carbon-carbon multi-bonds, at least one compound with Si-bonded hydrogen atoms, and at least one platinum (IV) complex of the aforementioned type. The invention also relates to novel alkali metal organo-dihydroazulenyls which can be used to produce metal complexes of the aforementioned type.

[0414] With the method described herein, complexes of precious metals, in particular platinum, can be produced in a high purity and good yield in a simple, reproducible and comparatively cost-effective manner. The method can also be carried out on an industrial scale with a comparable yield and purity of the target compounds. The metal complexes obtainable by means of the method described above represent a relatively cost-effective and particularly sustainable alternative to metal complexes comprising cyclopentadienyl ligands. This applies in particular to use as precatalysts and/or catalysts in chemical reactions for the production of crosslinkable silicone compositions, by means of which the production of silicone elastomers can be realized in a particularly simple, reliable and cost-effective manner. The platinum(IV) complexes, in particular [PtMe.sub.3(GuaMe)], can advantageously be used, for example, as precatalysts and/or catalysts in light-induced platinum-catalyzed hydrosilylation reactions, the hydrogenation of unsaturated compounds, and polymerization reactions in which the activation is effected by ultraviolet or visible radiation. In addition, the platinum(IV) complexes, in particular [PtMe.sub.3(GuaMe)], are particularly suitable as precursor compounds for producing high-quality substrates having at least one platinum-containing layer or at least one platinum layer on at least one surface. Furthermore, the present invention extends the spectrum of alkali metal organo-dihydroguaiazulenides that can be used for the production of metal complexes, in particular of the aforementioned type.

[0415] All features and advantages resulting from the claims, the description and the figures, including constructive details, spatial arrangements and method steps, can be essential to the invention, both in themselves and in the most diverse combinations.