WO2010101530A1

WO2010101530A1 - Silsesquioxane derivatives having sulfur containing substituents

Info

Publication number: WO2010101530A1
Application number: PCT/SG2010/000074
Authority: WO
Inventors: Jianwei Xu; Xiaobai Wang; Jun Zhang; Chaobin He
Original assignee: Agency for Science Technology and Research Singapore
Current assignee: Agency for Science Technology and Research Singapore
Priority date: 2009-03-04
Filing date: 2010-03-04
Publication date: 2010-09-10
Anticipated expiration: 2011-09-04

Abstract

The invention relates to a silsesquioxane compound of formula (I) having sulfur containing substituents, where A, R₁, R₂, R₃, R₄, R₅, X, p, q, r and s are as disclosed herein. Also, described are methods for their preparation and use as a lubricant.

Description

SILSESQUIOXANE DERIVATIVES HAVING SULFUR CONTAINING

SUBSTITUENTS

CROSS-REFERENCE TO RELATED APPLICATION

This application claims benefit of, and priority from, U.S. provisional application No. 61/202,492, filed on March 4, 2009, the contents of which are hereby incorporated herein by reference.

FIELD

The invention relates to silsesquioxane derivatives having sulfur containing substituents, their preparation methods and use as a lubricant.

BACKGROUND

Silsesquioxane is a compound having the empirical formula RSiOi.₅, where R is H or an organic substituent, such as alkyl, aryl, etc. Polyhedral oligomeric silsesquioxane (POS) molecules comprise silicon and oxygen atoms which are linked into well-defined regular structures, such as a cubic cage where the silicon atoms are at the corners. Among the POS structures, octameric silsesquioxane [(RSiOi.5)8] has generally received more attention and derivatives of it have been obtained. This is likely because of the well-defined cage structure, which has a nano-sized rigid inorganic core, and can be attached to eight functional groups to produce organic-inorganic hybrid structures. The POS structure has been employed as a pendant group for integration into a polymer backbone, to enhance the physical and mechanical properties of the polymer. The functionalization of POS corner substituents allows for development of a variety of materials that can be useful in different applications. For example, POS-containing materials produced may exhibit heat resistance, electrical insulation, flame resistance, and so on. They have been utilized for semiconductors, insulator materials, liquid crystalline materials, etc. WO 2008/017593 Al discloses polyhedral oligomeric silsesquioxane based fluorescent colorants.

Lubricants have been proposed in the art for use at temperatures of up to 200⁰C or higher. High temperature lubricants can have applications in different industries, such as automotive and aerospace. These lubricants are primarily synthetic esters derived from various polyhydroxyl compounds and carboxylic acids. US 7,217,683 discloses polyhedral oligomeric silsesquioxane and polyhedral oligomeric silicates as lubricants.

SUMMARY

The invention relates to a silsesquioxane derivative having sulfur containing substituents, their preparation methods and use as a lubricant.

According to one aspect of the present invention, there is provided a compound of formula (I) :

where

A is a silsesquioxane;

Ri is -(C(R^a)₂)χ- or -O-Si (R^a) ₂ (C (R^a) ₂) _x-, where each x is independently an integer of 1 to 6 and each R^a is independently a H or Ci-Cβ alkyl (and in an exemplary embodiment, -CH₂-CH₂- or -0-Si(Me)₂CH₂CH₂-), wherein when Ri is -O-Si (R^a)₂ (C(R^a)₂)_x-, the 0 atom of Ri bonds to Si on A;

X is S, SO, or SO₂;

each R₂, R₃, R₄ and R₅, when present, is independently a linear or branched alkyl group of formula C_nH_2n+I, where n is from 1 to 30, or a group of formula Ar(CH₂)_m-, where Ar is a Cβ-io aryl or a 5 to 10 membered heterocyclic group containing one or more heteroatoms, where each independently is N, 0 or S, and m is from 1 to 30, and

each p, q, r and s is independently from 0 to the total number of Si atoms in A, and the sum of p, q, r and s is from 4 to the total number of Si atoms in A.

Another aspect of the present invention are processes for preparing compounds of formula (I) as disclosed herein.

According to still a further aspect of the present invention, there is provided a lubricant comprising a compound of formula (I), as defined above.

According to yet another aspect of the present invention, there is provided the compound octa (vinyldimethylsilyl) -POS

Octa(vinyldimethylsilyl)-POS BRIEF DESCRIPTION OF FIGURES

FIGURE 1 discloses the differential scanning calorimetry (DSC) curve of a POS oil - (U-C₆Hi₃SCH₂CH₂Si(Me)₂OSiOi-S)₈.

FIGURE 2 discloses the differential scanning calorimetry (DSC) curve of a POS oil - (n-C₈Hi₇SCH₂CH₂Si (Me) ₂0Si0i.₅) β-

FIGURE 3 discloses the viscosity behavior of a POS oil - (n- C₆Hi₃SCH₂CH₂Si(Me)₂OSiOLs)₈ at (I) 25 ⁰C, (11)50 ⁰C, and (III) 100 °C.

FIGURE 4 discloses the viscosity behavior of a POS oil - (11-C₈Hi₇SCH₂CH₂Si (Me)₂OSiOi_-5) ₈ at (I) 25 ⁰C, (11)50 ⁰C, and (III) 100 ⁰C.

FIGURE 5 discloses the thermal aging effect on the thermal stability of POS oil measured by thermal gravimetric analysis (TGA) .

DETAILED DESCRIPTION

As described above, the present invention provides a compound of formula (I)

where

A, X, Ri, R₂, R₃, R₄, p, q, r and s are as defined above, In one embodiment, the substituent A in the compound of formula (I) is a polyhedral oligomeric silsesquioxane (POS) . For example, the POS may be

(SiO_{1 5})₆ (SiO_{1 5})₈ (SiO₁ S)₁₀ (SiO_{1 5}J₁₂

In an exemplary embodiment, the POS may be (SiOi.5)9-

In another embodiment, Ri in the compound of formula (I) is -CH₂-CH₂- or -OSi(Me)₂CH₂CH₂-, which bonds to a Si atom in the silsesquioxane. When Ri is -OSi(Me)₂CH₂CH₂-, the 0 atom bonds to the Si atom of the silsesquioxane. It will be understood that Ri binds to the silicon atom of A.

In still another embodiment, each R₂, R₃, R4 and R₅, when present, is independently a linear or branched alkyl group of formula C₂H_2n+I, where n is from 1 to 30, or a group of formula Ar (CH₂) _m-, where Ar is a C₆-io aryl group or a 5 to 10 membered heterocyclic group containing one or more heteroatoms, where each independently is N, 0 or S, and m is from 1 to 30. It will be understood that the 5 to 10 membered heterocyclic group may be a non-aromatic heterocyclic group or an aromatic heterocyclic group.

In yet another embodiment, the sum of p, q, r and s is 6, 8, 10 or 12.

For purposes of illustration, the Ci-₆ alkyl group, which is representative of the linear or branched alkyl group of formula C₂H_2n+I, may be, for example, methyl, ethyl, n-propyl, i-propyl, sec-propyl, n-butyl, i-butyl, sec-butyl, t-butyl, n-pentyl, i-pentyl, sec-pentyl, t-pentyl, n-hexyl, i-hexyl, 1, 2-dimethylpropyl, 2-ethylpropyl, l-methyl-2- ethylpropyl, l-ethyl-2-methylpropyl, 1, 1, 2-trimethylpropyl, 1, 1-dimethylbutyl, 2, 2-dimethylbutyl, 2-ethylbutyl, 1,3- dimethylbutyl, 2-methylpentyl or 3-methylpentyl .

For purposes of illustration, the Cβ-io aryl group, may be, for example, phenyl, indenyl, naphthyl, or azulenyl.

For purposes of illustration, the 5- to 10-membered non-aromatic heterocyclic group, may be, for example, pyrrolidinyl, pyrrolinyl, piperidinyl, piperazinyl, imidazolinyl, pyrazolidinyl, imidazolydinyl, morpholinyl, tetrahydropyranyl, oxathiolanyl, phthalimide or succinimide.

For purposes of illustration, the 5- to 10-membered aromatic heterocyclic, may be, for example, pyrrolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, imidazolyl, thiazolyl or oxazolyl.

For purposes of illustration, the group of formula Ar(CH₂)_m-, where Ar is a Cβ-io aryl or a 5 to 10 membered heterocyclic group , may comprise, for example, an alkyl as disclosed herein and having a C₆-1₀ aryl or a 5 to 10 membered heterocyclic group as disclosed herein.

In another aspect of the invention, disclosed is a process for the preparation of a compound of formula (I), by reacting a compound of formula (I¹) or (I^{1 1} ') with R' -SH, in the presence of a radical initiator,

A- ( CH=CH₂ ) p_+q+r+s ( I ¹ ) or A- ( OSi ( Me ) ₂CH=CH₂ ) _P+q+r+s ( I ¹ " )

wherein A is as defined above, and R¹ is R₂, R₃, R4 or R₅, as defined above, or R' -SH comprises a mixture of compounds having different R' groups. In still another aspect of the invention, disclosed is a process for the preparation of a compound of formula (I) , by reacting a compound of formula (I¹ ') or (I^{1 1} ' ' ) with R' ¹, in the presence of a radical initiator,

A- (CH₂CH₂-SH) _p+q+r+s (I") or

A- ( OSi (Me ) ₂CH₂CH₂SH ) _p+q+r+s ( I ¹ " ' )

wherein A is a defined above, R' ' is a precursor of R₂, R₃, R4 or R₅, as defined above, and has a terminal unsaturated bond.

For the purpose of illustration, Ri¹ is a vinyl group. For example, the compound of formula (I¹) or (I¹'') is

Octa(vinyl)-POS Octa(vinyldimethylsilyl)-POS

For purpose of illustration, R¹ ' is, for example a terminal alkene, such as 1-octene.

In the process for preparation of a compound of formula (I), A may be POS. In the family of POS structures, such as (RSiOi.5) e, (RSiO_1-5)S, (RSiOi_-5) ₁₀, and (RSiOi.5) 12) , the octameric POS structure ( (RSiOi. s) β) is generally understood to have good stability, facile synthesis and may be easily modified. The POS structures may be formed from hydrolysis or condensation reactions of simple RSiCl₃ or RSi(OR)₃ silanes where R is an aliphatic or an aromatic group. For instance, octameric silsesquioxane may be prepared in this way. The POS compounds may be synthesized by chemical modification of several functionalized POS precursors that possess reactive functional groups, such as a C=C double bond, as shown below. These functional groups allow for further chemical modification to prepare POS compounds having different properties.

Octa(vinyl)-POS Octa(vinyldimethylsilyl)-POS

In yet another aspect of the present invention, there is provided a lubricant (a "POS lubricant") comprising the compound of formula (I), as defined above. POS lubricants of the invention may be prepared by reacting octa (vinyl) -POS or octa (vinyldimethylsilyl) -POS with various thiol compounds in the presence of free radical initiators such as 2, 2-azobisisobutyronitrile (AIBN), benzoyl peroxide (BPO), etc. The thiol compounds may be linear or branched (e.g.,

R' -SH). The free radical addition reaction usually completes within 3-5 hours as monitored by ¹H nuclear magnetic resonance (NMR) spectroscopy. Representative chemical structures of POS lubricants are shown below.

(RSiO_{1 5})₆ (RSiO_{1 5})₈ (RSiO_{1 5}J₁₀ (RSiO_{1 5})₁₂

Example of Homoleptic POSS Derivatives [RSiO_{1 5}]_{6 8 10 or 12} R = CH₂CH₂SR¹J OSi(Me)₂CH₂CH₂SR¹

When preparing a POS lubricant, the desired amount of POS and thiol compound is placed into a reaction vessel. The thiol compound is added in the reaction mixture in an excess of 0 mol %-100 mol % relative to the amount of POS. After the addition reaction is complete, the excess thiol compound can be recovered by vacuum distillation when the product is a liquid or by washing with a suitable organic solvent including acetonitrile, acetone, methanol, etc. when the product is a solid. The reaction time is generally dependent upon the type and length of the alkyl group of the thiol compound. In general, the larger the size of the alkyl group of the thiol compound, the longer the reaction time. For example, the reaction time is generally less than 5 hours when the number of carbon atoms of the thiol compound is not more than 12. Radical initiators can be chosen from azos and peroxides, such as AIBN and BPO, with AIBN being an exemplary initiator. The reaction may be carried out in an organic solvent including benzene, toluene, xylene, etc, but usually in the absence of any organic solvents, particularly when the product is a liquid and the number of carbon atoms in the thiol compound is not more than 12. POS lubricants with different corner substituents can be synthesized by reacting a mixture of thiol compounds with octa (vinyl) -POS or octa (vinyldimethylsilyl) -POS . For example, a mixture of compounds of the average general formula (1-1-C₆Hi₃SCH₂CH₂Si (Me) ₂0Si0i.₅) ₄ (n-C₈Hi₇SCH₂CH₂Si (Me) ₂0Si0i.₅) ₄ can be prepared by heating n-C₆Hi₃SH, n-C₈Hi₇SH and octa (vinyldimethylsilyl) -POS in a molar ratio of 6:6:1, respectively, in the presence of AIBN at 8O⁰C. In another embodiment, a mixture of the compounds of average general formula (R-C₆Hi₃SCH₂CH₂SiOi_-5) 4 (n-C₈Hi₇SCH₂CH₂Si0i.₅) ₄ can be prepared by heating n-C₆Hi₃SH, n-C₈Hi₇SH and octa (vinyl) -POS in a molar ratio of 6:6:1, respectively, in the presence of AIBN at 8O⁰C. Other combinations of POS lubricant can be obtained following a similar synthetic method to those described above. The reaction conversion estimated based on the POS reactant is almost quantitative. Observed, isolated synthetic yields have been more than 99%. Moreover, the product is chemically pure enough for further characterization after removal of the excess thiol reactant.

Similar to traditional lubricants, the viscosity of POS derivatives has been observed to behave like a Newtonian liquid. The dynamic viscosity of POS lubricants derived from octa (vinyldimethylsilyl) -POS is around 0.15-0.17 Pas at 25°C. The dynamic viscosity drops to around 0.053-0.066 Pas at 50°C and further goes down to around 0.017-0.019 Pas at 100⁰C (Table 1) . In contrast, a lubricant derived from oct (vinyl) -POS shows a relatively higher dynamic viscosity, likely due to the more rigid structure. The surface tension for POS oil has been observed to be relative to the length of corner chains, ranging from 27.7-31.3 mNirf¹ (Table 2) . In principle, the introduction of flexible chains to POS structures leads to a reduction of the melting point. POS derivatives (n-C₆Hi₃SCH₂CH₂Si (Me) 2OSiOi_-5) ₈ and ^-C₈Hi₇SCH₂CH₂Si (Me) ₂0Si0i_-5) ₈ have been observed to have freezing and melting points of less than - 8O⁰C (Figures 1 and 2) . TABLE 1

Tabulated viscosity data for selected POS lubricants

Viscosity Viscosity Viscosity

Composition (Pas) at (Pas) at (Pas) at

25°C 50⁰C 100⁰C fH^~θ_eftχ_TS€-H-2€H₂-S-i-f€H_τ)-2θ-Siθiτ5H- -0-0-54— -θ÷θi-7 (Ji-C₈H₁₇SCH₂CH₂Si (CH₃) ₂OSiO₁.₅) „ 0.15 0.053 0.017 (n-C₁₀H₂₁SCH₂CH₂Si (CH₃) ₂OSiO₁.₅) ₈ 0.17 0.066 0.017 (11-C₁₂H₂₅SCH₂CH₂Si (CH₃) ₂OSiO₁₁₆) ₈ 0.17 0.066 0.019 (H-C₆H₁₃SCH₂CH₂SiO_1-5)_S 0.25 0.087 0.021

TABLE 2

Tabulated physical properties for selected POS lubricants

Surface Freezing Melting

Density

Composition tension point point (gem^"3)

(mNrrf¹) ("C) (°C)

(n-C₅H₁₃SCH₂CH₂Si (CH₃) ₂OSiO_1-5) _E 1.06 27 .7 < -80 < -80 U-C₈H₁₇SCH₂CH₂Si (CH₃) ₂OSiO₁.₅) _ε 1.04 29 .8 < -80 < -80 (n-C₁₀H₂₁SCH₂CH₂Si (CH₃) ₂OSiO_1-5) 1.02 31 .3 -40 -26 ~ -9 (n-C₁₂H₂₅SCH₂CH₂Si (CH₃) ₂OSiO_1-5) 1.00 31 .3 -7 2 ~ 10

TGA experiments were conducted to observe the relative thermal stability of POS lubricants. The decomposition temperature is defined as the temperature at which 5% weight loss occurs. For POS products derived form octa ( vinyldimethylsilyl ) -POS, their decomposition temperatures were measured at between 340-402 ⁰C in air and nitrogen (Table 3) . For POS product derived form octa (vinyl) -POS, the decomposition temperature was observed to be between 337-400 ⁰C in air and nitrogen (Table 4) . Both of these two series of POS derivatives display high decomposition temperatures. The thermal aging tests were conducted by using a similar amount of the compounds (15-18 mg) , which is placed on a sample holder and is heated at 220⁰C for about 500 min. All POS lubricants were observed to have thermal stability with a range of weight loss of 2.25%-7.25%.

TABLE 3

Tabulated TGA Data for POS lubricant

Residue Residue

N₂ Air

Composition (%) at (%) at (⁰C) (⁰C) 900⁰C 900⁰C

(n-C₆H₁₃SCH₂CH₂Si (CH₃) ₂0Si0i.₅) _ε 378 35.0 360 30.0 (n-C₈Hi7SCH₂CH₂Si (CH₃) ₂0Si0i.₅) _E 368 31.0 338 26.5 (n-Ci₀H₂iSCH₂CH₂Si (CH₃) ₂0Si0i.₅) 400 26.9 357 24.1 (n-Ci₂H₂₅SCH₂CH₂Si (CH₃) ₂0Si0i.₅) 400 24.4 353 21.3 (n-C₁₄H₂₉SCH₂CH₂Si (CH₃) ₂0Si0i.₅) 385 18.3 357 17.0 (n-Ci₅H₃₃SCH₂CH₂Si (CH₃) ₂0Si0i.₅) 363 19.6 337 17.8 (n-Ci₈H₃₅SCH₂CH₂Si (CH₃) ₂0Si0i.₅) 360 16.1 362 17.2

TABLE 4

Tabulated TGA Data for POS lubricant

Residue Residue

Air

Composition Nitrogen (⁰C) (%) at (%) at 900°C (⁰C) 900°C

(-1-C₆HI₃SCH₂CH₂SIOLS) ₈ 387 37.3 372 41.0

Cn-C₈Hi₇SCH₂CH₂SiOi_-5) s 382 33.8 358 37.4

(H-Ci₀H₂₁SCH₂CH₂SiO_Ls)₈ 402 31.7 384 35.2

U-C₁₂H₂₅SCH₂CH₂SiOi_-5) ₈ 373 31.5 360 32.0

Cn-C₁₄H₂₉SCH₂CH₂SiO_L5) ₈ 385 26.0 341 28.0

Jn-C₁₆H₃₃SCH₂CH₂SiOi.₅) ₈ 354 24.2 342 27.0

(-1-Ci₈H₃₅SCH₂CH₂SiOLs)₈ 373 23.5 340 26.5

It is desired that a high temperature lubricant composition possess a low evaporation loss and not form deposits or varnish when exposed to high temperature environments for a given time period. In order to measure the evaporation loss of the lubricant at a specific temperature, a lubricant sample is maintained in an oven at the specific temperature for an extended period of time and the weight loss is then determined. Evaporation loss, deposit formation tendency, and residual oil fluidity are evaluated using the following procedure: one gram of lubricant is placed in a glass vial. The test condition at a specific temperature is held for a few hours or few days. Evaporation loss, deposit formation tendency, and flow properties of the lubricant after this procedure are measured by weight and by visual observation, respectively. The evaporation loss was calculated according to the following formula:

weight loss after heating

Evaporation loss (%) = x 100% initial weight of lubricant before heating

The POS lubricants provided by the present invention have been observed to have slow evaporation loss values under the measured temperature. For instance, the evaporation loss for POS derivative ^-C₆Hi₃SCH₂CH₂Si (Me) ₂Si0i.₅) 8 at 218 ⁰C for 24 h was 2.5% and no deposit was observed. Even after heating for 96 h, it was still a liquid and only 11% had evaporated (Table 5) . The POS lubricant (n-Ci₂H₂₅SCH₂CH₂OSi (Me) ₂0Si0i.₅) ₈ demonstrated the lowest evaporation loss (7.7%) and it remained fluid after heating for 115h at 218 ⁰C. Isothermal experiments at higher temperature of 288 ⁰C were carried out and the lowest evaporation loss (0.7%) was observed for lubricant (n-Ci₂H₂₅SCH₂CH₂Si (Me) ₂0Si0i.₅) ₈ (Table 5) . The lubricant (n-Ci₂H₂₅SCH₂CH₂Si (Me) ₂0Si0i.₅) ₈ exhibited the highest temperature performance among the four lubricants listed in Table 6. TABLE 5

Tabulated weight loss after thermal aging at 218 ° ¹C

Composition\weight loss 9h 24h 48h 72h 96h 115h 163h

(n-C₆H₁₃SCH₂CH₂Si (CH₃) ₂0Si0i.₅) _B 1.1 2.5 5.9 11.0 15.8

Tn^PITSϋHJCHIST ⁽-CHJ)T0STCOT7 2T5^" ^'5V6^' T2T2^" (11-C₁₀H_2ISCH₂CH₂Si (CH₃) ₂0Si0i.₅) ₈ 1.9 4.6 10.8 (n-C₁₂H₂₅SCH₂CH₂Si (CH₃) ₂0Si0i.₅) 8 1.2 3.4 7.7

TABLE 6

Tabulated thermal aging data at 288 ⁰C for 5.5 hours

Composition weight Deposit, Fluidity, loss visual visual

(n-C₆H₁₃SCH₂CH₂Si (CH₃) ₂0Si0i.₅) ₈ 7.7% Not

Fluid observed

(n-C₈H₁₇SCH₂CH₂Si (CH₃) ₂0Si0i.₅) ₈ 5.6% Not Fluid observed

(n-Ci₀H₂₁SCH₂CH₂Si (CH₃) ₂0Si0i.₅) ₈ 4.2% Not Fluid observed

(n-Ci₂H₂₅SCH₂CH₂Si (CH₃) ₂OSiO_1-5) ₈ 0.7% Not Fluid observed

EXAMPLES

The following examples are intended as exemplary only and not in any way intended to limit the scope of the present invention.

EXAMPLE 1

Preparation of (U-C₆Hi₃SCH₂CH₂Si(Me)₂OSiOi S)₈

A potion of octa (vinyldimethylsilyl) silsesquioxane (20.016 g, 163.0 mmol) was placed into a two-necked round- bottom flask equipped with a magnetic stirrer. 1-Hexylthiol (23.128 g, 195.6 mmol) was added to POS and the mixture was stirred and purged with pure nitrogen gas for half an hour. A catalytic amount of 2, 2-azobis (isobutylcyanate) (AIBN) (322 mg) was added and the mixture was allowed to continue to purge nitrogen for another 15 minutes. Then the mixture was heated up to 80°C and maintained at this temperature for 5 hours. After that, the reaction mixture was subject to NMR analysis. The characteristic signals of vinyl units in POS starting materials at 5.73-6.18 ppm disappeared, indicating the completeness of the reaction. The crude product was then vacuum-distilled to recover unreacted 1-hexylthiol and then to afford a light yellow oily liquid (35.21 g; yield, 99.3 %) . The product was pure enough for further chemical analysis . 1HNMR δ 2.62 ~ 2.56 (m, 16H), 2.51 (t, 16H), 1.59 ~ 1.54 (m, 16H), 1.43 ~ 1.23 (m, 48H), 1.00 ~ 0.96 (m, 16H), 0.91 (t, 24H), 0.19 (s, 48H) . ¹³C NMR δ 32.34, 31.85, 29.91, 29.05, 26.89, 22.93, 18.85, 14.39, 0.17. ²⁹Si NMR: δ 11.74, -108.92. MALDI-TOF MS CaIc. C₈₀H^SiI₆O₂₀S₈: 2172.22. Observed: [M+Ag]⁺, 2279.90.

EXAMPLE 2

Preparation of (n-C₈Hi₇SCH2CH2Si (Me) 2OSiOi.₅) ₈

Following the procedures outlined in Example 1, octa (vinyldimethylsilyl) silsesquioxane (20.017 g) was reacted with 1-octylthiol (28.614 g) to afford the product as a light yellow oily liquid (39.12 g; yield, 99.7%) . 1HNMR δ 2.60 ~ 2.56 (m, 16H) , 2.51 (t, 16H) , 1.59 ~ 1.55 (m, 16H) , 1.42 ~ 1.20 (m, 80H) , 1.00 ~ 0.97 (m, 16H) , 0.90 (t, 24H) , 0.19 (s, 48H) . δ ¹³C NMR δ 32.36, 32.21, 29.95, 29.60, 29.40, 26.90, 23.01, 18.86, 14.43, 0.17. ²⁹Si NMR δ 11.73, - 108.92. MALDI-TOF MS CaIc. C₉₆H_2I6Si_I6O₂₀S₈: 2396.65. Observed: [M+Ag]⁺, 2504.02

EXAMPLE 3

Preparation of (H-Ci₀H₂ISCH₂CH₂Si (Me) ₂OSiOi.₅) ₈

Following the procedures outlined in Example 1, octa (vinyldimethylsilyl) silsesquioxane (18.025 g) was reacted with 1-decylthiol (25.628 g) to afford the product as a light yellow oily liquid (38.33 g; yield, 99.5%) . 1HNMR: δ 2.60 ~ 2.54 (m, 16H) , 2.51 (t, 16H) , 1.61 ~ 1.53 (m, 16H) , 1.42 ~ 1.21 (m, 112H) , 1.00 ~ 0.97 (m, 16H) , 0.88 (t, 24H) , 0.19 (s, 48H) . ¹³C NMR δ 32.44 , 32.33, 30.02, 29.74, 29.48, 26.98, 23.09, 18.92, 14.49, 0.23. ^^aSi NMR δ 11.76, - 108.91. MALDI-TOF MS CaIc. Cn₂H₂₄SSiI₆O₂₀S₈: 2621.08. Observed: [M+Ag]⁺, 2729.32

EXAMPLE 4 Preparation of (n-Ci2H₂5SCH₂CH2Si (Me) 2OSiOi.₅) β

Following the procedures outlined in Example 1, octa (vinyldimethylsilyl) silsesquioxane (15.016 g) was reacted with 1-dodecylthiol (29.70 g) to afford the product as a light yellow oily liquid (34.57 g; yield, 99.2%). 1HNMR δ 2.60 ~ 2.54 (m, 16H) , 2.51 (t, 16H) , 1.60 ~ 1.53 (m, 16H) , 1.40 ~ 1.20 (m, 144H) , 1.00 ~ 0.97 (m, 16H) , 0.88 (t, 24H) , 0.19 (s, 48H) . ¹³C NMR δ 32.40, 32.32, 30.04, 30.01, 29.74, 29.46, 26.94, 23.07, 18.88, 14.47, 0.20. 2⁹Si NMR δ 11.76, -108.90. MALDI-TOF MS CaIc. Ci₂₈H₂₈₀SiI₆O₂₀S₈: 2845.52. Observed: [M+Ag]⁺, 2953.88.

EXAMPLE 5

Preparation of (n-Ci4H₂9SCH₂CH2Si (Me) ₂OSiOi.₅) β

A potion of octa (vinyldimethylsilyl) silsesquioxane (0.5 g, 0.79 mmol) and 1-tetradecylthoil (2.184 g, 9.48 mmol) were placed into a two-necked round-bottom flask with 50 ml of toluene. The flask was equipped with a magnetic stirrer and purged with pure nitrogen gas for half an hour. A catalytic amount of AIBN (15.55 mg) was then added and the mixture was allowed to continue to purge nitrogen for another

15 minutes. Then the mixture was heated up to 8O⁰C and this temperature was maintained overnight (18 hours) . After that, the reaction mixture was subject to NMR analysis. The characteristic signals of vinyl units in POS starting materials at 5.73-6.18 ppm disappeared, indicating the completeness of the reaction. The solvent acetone was added to the reaction mixture, and the resulting white solid was filtered and collected as a white solid after washing with acetone. The product was pure enough for further chemical analysis. ¹HNMR δ 2.60 ~ 2.56 (m, 16H), 2.51 (t, 16H), 1.60 ~ 1.55 (m, 16H), 1.42 ~ 1.20 (m, 176H), 1.00 ~ 0.96 (m, 16H), 0.90 (t, 24H), 0.19 (s, 48H) . ¹³C NMR δ 32.44, 32.31, 30.08, 29.74, 29.47, 26.97, 23.06, 18.90, 14.45, 0.21. 2⁹Si NMR δ 11.76, -108.88. MALDI-TOF MS CaIc. Ci₄₄H₃I₂SiI₆O₂₀S₈: 3069.95. Observed: [M+Ag]⁺, 3178.90

EXAMPLE 6

Preparation of (n-Ci₆H₃3SCH₂CH₂Si (Me) ₂OSiOi.₅) β and (H-Ci₈H₃₇SCH₂CH₂Si (Me) ₂OSiOi.₅) β

Following the procedures outlined in Example 5, (n-Ci₆H₃₃SCH₂CH₂Si (Me) ₂0Si0i.₅) ₈ and (n-Ci8H₃₇SCH₂CH₂Si (Me) ₂OSiOi.₅) ₈ were prepared. (H-Ci₆H₃₃SCH₂CH₂Si(Me)₂OSiOLs)₈: ¹HNMR δ 2.60 ~ 2.56 (m, 16H) , 2.51 (t, 16H) , 1.59 ~ 1.53 (m, 16H) , 1.42 ~ 1.20 (m, 208H) , 1.00 ~ 0.96 (m, 16H) , 0.88 (t, 24H) , 0.19 (s, 48H) . ¹³C NMR δ 32.42, 32.32, 30.08, 29.74, 29.46, 26.96, 23.06, 18.90, 14.45, 0.20. ²⁹Si NMR δ 11.78, -108.86. MALDI-TOF MS CaIc. Ci₆₀H₃₄₄SiI₆O₂₀S₈: 3294.38. Observed: [M+Ag]⁺, 3403.51. (n-Ci₈H₃₇SCH₂CH₂Si (Me)₂OSiOi_-5) ₈ : ¹HNMR δ 2.60 ~ 2.56 (m, 16H) , 2.51 (t, 16H) , 1.59 ~ 1.53 (m, 16H) , 1.42 ~ 1.20 (m, 240H) , 1.00 ~ 0.96 (m, 16H) , 0.88 (t, 24H) , 0.19 (s, 48H) . ¹³C NMR δ 32.40, 32.32, 30.10, 29.74, 29.46, 26.93, 23.06, 18.88, 14.45, 0.19. ²⁹Si NMR δ 11.77, -108.88. MALDI-TOF MS CaIc. Ci₇₆H₃₇₆Si_I6O₂₀S₈: 3518.81. Observed: [M+Ag]⁺, 3627.87. EXAMPLE 7

Preparation of (H-C₆Hi₃SCH₂CH₂SiOLs)₈

A potion of octa (vinyl) silsesquioxane (20.05 g, 31.67 mmol) was placed into a two-necked round-bottom flask equipped with a magnetic stirrer. 1-Hexylthiol (37.44 g, 316.7 mmol) was added to POS and the mixture was stirred and purged with pure nitrogen for half an hour. A catalytic amount of AIBN (520 mg) was added and the mixture was allowed to continue to purge nitrogen for another 15 minutes. Then the mixture was heated up to 80⁰C and maintained at this temperature for 5 hours. After that, the reaction mixture was subject to NMR analysis. The characteristic signals of vinyl units in POS starting materials at 5.73-6.18 ppm disappeared, indicating the completeness of the reaction. The crude product was then vacuum-distilled to remove the unreacted 1-hexylthiol and the residue was a light yellow oily liquid (49.50 g, yield, 99%) . The product was pure enough for further chemical analysis. ¹HNMR δ 2.62-2.57 (m, 16H), 2.52 (t, 16H), 1.62- 1.53 (m, 16H), 1.42-1.24 (m, 48H), 1.04-0.99 (m, 16H), 0.90 (t, 24H). ¹³C NMR δ 32.35, 31.85, 29.89, 29.06, 26.37, 22.96, 14.39, 13.47 ²⁹Si NMR δ -68.58. MALDI-TOF MS CaIc. C₆₄Hi₃₆Si₈Oi₂S₈: 1578.98. Observed: [M+Ag]⁺, 1687.11.

EXAMPLE 8 Preparation of In-CeHi₇SCH₂CH₂SiOi.₅) β

A potion of octa (vinyl) silsesquioxane (0.5 g, 0.79 mmol) was placed into a two-necked round-bottom flask equipped with a magnetic stirrer. 1-Octylthiol (1.155 g, 7.9 mmol) was added to POS and the mixture was stirred and purged with pure nitrogen gas for half an hour. A catalytic amount of AIBN

(13 mg) was added and the mixture was allowed to continue to purge nitrogen for another 15 minutes. Then the mixture was heated up to 8O⁰C and maintained at this temperature for 5 hours. After that, the reaction mixture was subject to NMR analysis. The characteristic signals of vinyl units in POS starting materials at 5.73-6.18 ppm disappeared, indicating the completeness of the reaction. The crude product was then vacuum-distilled to remove the unreacted 1-octylthiol and the residue was collected after washing with a bit of acetone. The product was pure enough for further chemical analysis. ¹HNMR δ 2.62-2.57 (m, 16H) , 2.51 (t, 16H) , 1.62- 1.53 (m, 16H) , 1.42-1.22 (m, 80H) , 1.03-0.99 (m, 16H) , 0.88 (t, 24H) . ¹³C NMR 532.30, 32.19, 29.91, 29.59, 29.37, 26.31, 23.00, 14.41, 13.41. ²⁹Si NMR δ -68.67. MALDI-TOF MS CaIc. C₆₄Hi₃₆Si₈Oi₂S₈: 1803.41. Observed: [M+Ag]⁺, 1911.18.

EXAMPLE 9

Following the procedures outlined in Example 5, (n-CioH2iSCH₂CH₂SiOi.5)8, (H-Ci₂H₂₅SCH₂CH₂SiOL₅) β, (-1-Ci₄H₂₉SCH₂CH₂SiOi.₅) ₈, (11-Ci₆H₃₃SCH₂CH₂SiOi_-5) ₈, (11-Ci₈H₃₇SCH₂CH₂SiOi.₅) ₈ are prepared.

(11-CiOH₂ISCH₂CH₂SiOL₅) β : ¹HNMR δ 2.64-2.57 (m, 16H) , 2.51 (t, 16H) , 1.62-1.53 (m, 16H) , 1.42-1.22 (m, 112H) , 1.03-0.99 (m, 16H) , 0.88 (t, 24H) . ¹³C NMR δ 32.34, 32.28, 29.97, 29.70, 29.42, 23.04, 14.45, 13.44. ²⁹Si NMR δ -68.65. MALDI-TOF MS CaIc. C₈₀Hi₆₈Si₈Oi₂S₈: 2027.85. Observed: [M+Ag]⁺, 2135.42.

(n-Ci2H₂₅SCH₂CH₂Si0i.₅)₈: ¹HNMR δ 2.64-2.54 (m, 16H) , 2.51 (t, 16H) , 1.64-1.53 (m, 16H) , 1.41-1.22 (m, 144H) , 1.03-0.99 (m, 16H) , 0.88 (t, 24H) .¹³C NMR δ 32.36, 32.31, 30.03, 29.73, 29.45, 26.37, 23.06, 14.46, 13.45. ²⁹Si NMR δ -68.63. MALDI- TOF MS CaIc. C₉₆H₂₀₀Si₈Oi₂S₈: 2252.28. Observed: [M+Ag]⁺, 2360.84.

(11-Ci₄H₂₉SCH₂CH₂SiO_L5) ₈ : ¹HNMR δ 2.62-2.57 (m, 16H) , 2.51 (t, 16H) , 1.62-1.53 (m, 16H) , 1.42-1.21 (m, 176H) , 1.03-0.99 (m, 16H) , 0.88 (t, 24H) . ¹³C NMR δ 32.34, 32.31, 30.07, 30.05, 29.96, 29.73, 29.43, 26.34, 23.05, 14.45, 13.43. ²⁹Si NMR δ - 68.58. MALDI-TOF MS CaIc. Cn₂H₂₃₂Si₈Oi₂S₈: 2476.71. Observed: [M+Ag]⁺, 3033.87.

(U-Ci₆H₃₃SCH₂CH₂SiOLs)₈: ¹HNMR δ 2.61-2.57 (m, 16H) , 2.51 (t, 16H) , 1.62-1.52 (m, 16H) , 1.42-1.20 (m, 208H) , 1.04-0.99 (m, 16H) , 0.88 (t, 24H) ¹³C NMR δ 32.40, 32.31, 30.09, 29.74, 29.47, 26.39, 23.06, 14.45, 13.47. ²⁹Si NMR δ -68.58. MALDI- TOF MS CaIc. 0144H₂₉₆Si₈Oi₂S₈: 2701.14. Observed: [M+Ag]⁺, 2809.72.

(U-Ci₈H₃₇SCH₂CH₂SiOLs)₈: ¹HNMR δ 2.61-2.57 (m, 16H) , 2.51 (t, 16H) , 1.62-1.52 (m, 16H) , 1.42-1.20 (m, 240H) , 1.01 (t, 16H) , 0.88 (t, 24H) . δ ¹³C NMR δ 32.42, 32.31, 30.10, 29.74, 29.47, 26.42, 23.05, 14.44, 13.49. ²⁹Si NMR δ -68.59. MALDI- TOF MS CaIc. Ci₆₀H₃₂₈Si₈Oi₂S₈: 2925.57. Observed: [M+Ag]⁺, 3033.55.

EXAMPLE 10 Following the procedures outlined in Example 1,

(n-C6Hi₃SCH₂CH₂SiOi.₅) ₄ (11-CsHi₇SCH₂CH₂SiO_Ls) ₄ was prepared. 1HNMR δ 2.59 (t, 16H) , 1.61-1.53 (m, 16H) , 1.45-1.20 (m, 64H) , 1.01 (t, 16H) , 0.88 (m, 24H) .

Claims

CLAIMS :

1. A compound of formula (I) :

where

A is a silsesquioxane,

Ri is -(C(R^a)₂)χ- or -O-Si (R^a) ₂ (C (R^a) ₂) x~, where each x is independently an integer of 1 to 6 and each R^a is independently a H or Ci-Cβ alkyl, wherein when Ri is -O-Si (R^a)₂ (C(R^a)₂)χ-, the 0 atom of Ri bonds to Si on A,

X is S, SO, or SO₂,

each R₂, R3, R4 and R₅, when present, is independently a linear or branched alkyl group of formula C_nH_2nH-I, where n is from 1 to 30, or a group of formula Ar (CH₂) _m-, where Ar is a Cβ-io aryl or a 5 to 10 membered heterocyclic group containing one or more heteroatoms, where each independently is N, 0 or S, and m is from 1 to 30; and

2. The compound of formula (I) according to claim 1, wherein A is a polyhedral oligomeric silsesquioxane

(POS) .

3. The compound of formula (I) according to claim 1 or 2, wherein the sum of p, q, r and s is 6, 8, 10 or 12.

4. The compound of formula (I) according to any one of claims 1 to 3, wherein A is

(SiO₁₅)₆ (SiO_1s)₈ (SiO₁₅J₁₀ (SiO_1S)₁₂

5. The compound of formula (I) according to any one of claims 1 to 4 , wherein Ri is -CH₂-CH₂- and bonds to a Si atom of A.

6. The compound of formula (I) according to any one of claims 1 to 4, wherein Ri is -OSi(Me)₂CH₂CH₂- and the 0 atom of -OSi(Me)₂CH₂CH₂- bonds to a Si atom of A.

7. The compound of formula (I) according to any one of claims 1 to 6, wherein each R₂, R₃, R4 and R₅, when present, is independently a linear or branched alkyl group of formula C₂H_2n+I, where n is from 1 to 30.

8. The compound of formula (I) according to any one of claims 1 to 6, wherein each R₂, R₃, R4 and R₅, when present, is independently a group of formula Ar (CH₂) _m-, where Ar is a Cε-io aryl group or a 5 to 10 membered heterocyclic group and m is from 1 to 30.

9. The compound of formula (I) according to any one of claims 1 to 8, wherein A is (SiOi.5) 8-

10. A process for the preparation of a compound of formula

(I), as defined in claim 1, 2, 3, 4, 5, 6, 7, 8 or 9, comprising: - reacting a compound of formula (I¹) or (I¹'') with R' -SH, in the presence of a radical initiator,

A- ( CH=CH₂ )p_+q+r+s (I ¹ ) or

A- (OSi (Me) 2CH=CH₂) _P+q+r+s (I ^{1 1} ' )

wherein A is as defined in claim 1, 2, 3, 4, 5, 6, 7, 8 or 9, and R' is R₂, R₃, R₄ or R₅, or a mixture thereof.

11. A process for the preparation of a compound of formula

(I), as defined in claim 1, 2, 3, 4, 5, 6, 7, 8 or 9, comprising:

- reacting a compound of formula (I¹') or (I¹' ¹') with R' ' , in the presence of a radical initiator,

A- (CH₂CH₂-SH) _p+q+r+s (I¹ ' ) or A- (OSi (Me) 2CH₂CH₂SH) _p+q+r+s (I¹ ' ' ' )

wherein R' ' is a precursor of R₂, R₃, R₄ or R₅ and has a terminal unsaturated bond.

12. The process according to claim 10 or 11, wherein the free radical initiator is 2, 2-azobis (isobutylcyanate) (AIBN) .

13. The process according to claim 10 or 11, wherein the free radical initiator is benzoperoxide (BPO) .

14. A lubricant comprising a compound as defined in claim 1, 2, 3, 4, 5, 6, 7, 8 or 9.

15. The compound octa ( vinyldimethylsilyl) -POS

Octa(vinyldimethylsilyl)-POS