The invention relates to a method of preparation of polydicyclopentadiene and use of ruthenium complexes acting as (pre)catalysts in ring-opening metathesis polymerization (ROMP) of dicyclopentadiene (DCPD).

Olefin metathesis is an important tool applied in organic synthesis (Handbook of Metathesis, Volume I-III, Editor: Grubbs, R. H.; Wiley- VCH, 2003). In the state of the art there are known many ruthenium complexes which actively catalyze olefin metathesis (see reviews by Vougioukalakis, G. C; Grubbs, R. H. Chem. Rev. 2010, 110, 1746. It was shown that III- generation complexes (such as Gru-III, Ind-III) are highly useful (pre)catalysts of ROMP reactions.

Gru III Ind lll

Third generation catalysts initiate metathesis reactions very quickly, while in some applications of metathesis, such as, e.g., mold ROMP, it is preferred to use a (pre)catalyst which does not initiate the reaction immediately after it has been added to the substrate but only after an appropriate initiation by means of chemical agents, temperature or light. Complexes characterized by a delayed initiation are often referred to as "latent catalysts"; see reviews by Monsaert, S.; Vila, A. L.; Drozdzak, R.; Van Der Voort, P.; Verpoort, F., Chem. Soc. Rev., 2009, 38, 3360. Examples of "latent catalysts" are complexes, A-F, and also P-l and P-2 which were recently obtained (oral presentation of the results, ISOM XIX Renes, 10-15.07.2011).

Mold ROMP allows to obtain finished products. Polydicyclopentadiene is characterized among others by low moisture absorption and resistance to tensions and high temperatures. Therefore, components of vehicles or specialized containers for the chemical industry are more often produced through (mold) ROMP of dicyclopentadiene. It was shown that P-l complex catalyzes the ROMP reaction of cyclooctadiene carried out in dichloromethane, at room temperature. This reaction, however, proceeds with a very low conversion of the substrate. In the presence of a chemical activator, the reaction, however, proceeds much faster and with a higher conversion of the substrate. It should be noted, however, that such reactions were performed using 1 mol % of (pre)catalyst. It was shown also (using an example of hydrogen chloride) that acids activate P-1 and P-2 catalysts by cleavage of a covalent bond between the ruthenium atom and a nitrogen atom. As a result, an acid moiety of an acid (in the example shown - chloride anion) used for activation becomes an anionic ligand, and a new (pre)catalyst resulting from activation is described by formula la.

P-1 or P-2

It was noted in the course of own studies that ruthenium complexes represented by formula 1:

having in its structure a covalent metal-nitrogen bond and a phosphorus ligand do not initiate (or initiate very slowly) the ROMP reaction of dicyclopentadiene (DCPD) (carried out without a solvent) at a temperature of 33°C. It was, however, found surprisingly that at a temperature of 35°C and higher, very small amounts (0.01 mol % and less) of complexes of formula 1, exhibit, following the chemical activation, a high catalytic activity and polymerize DCPD very effectively. In addition, it was surprisingly found that complexes of formula 1 in which one of neutral ligands L 1 , L 2 is a N-heterocyclic carbene ligand, do not require the chemical activation and used in the amount equal to or less than 0.01 mol % effectively catalyze polymerization of DCPD, at a temperature of 35°C and higher.

The type of an anionic ligand may be important for the effectiveness of a (pre)catalyst in ring-opening metathesis polymerization. It is suspected that high effectiveness of catalysts of formula D is due in a large part to a lesser degree of a bimolecular decomposition of an active complex, which in turn results from the presence of a phenoxylate ligand. Catalysts containing phenoxylate or carboxylate anionic ligands are obtained in the reaction of classic complexes (with chloride anionic ligands) with the appropriate phenoxylate or carboxylate salts. This creates additional synthetic problems, extends the time and increases the cost of obtaining a (pre)catalyst. The cost of a catalyst is however a key element determining the possibility of its application in the synthesis of polydicyclopentadiene on an industrial scale, due to its relatively low price. The ease of synthesis, a low price and the possibility to introduce a modified anionic ligand into the structure of complexes of formula 1 by adding the corresponding acid to its mixture with a monomer (e.g. , dicyclopentadiene) may determine its industrial utility.

For example, use of p-toluenesulfonic acid (TsOH) to activate complex 1 allows to obtain a different complex of formula lb, containing a tosylate anion as an anionic ligand.

Therefore, the object of the present invention is a method of preparation of polydicyclopentadiene in ring-opening metathesis polymerization in which dicyclopentadiene is polymerized in the presence of a ruthenium (pre)catalyst of general formula 1

wherein

X is an anionic ligand;

L 1 and V 2 are neutral ligands;

R ¹ is H, -C _1-20 alkyl, -C ₂ - ₂ 0 alkenyl, -C ₂ - ₂ o alkynyl or -C ₅ _ ₁₀ aryl;

R ² , R ³ , R ⁴ and R ⁵ are, independently, H, halogen, CrC ₁₆ alkyl, CrC ₁₆ alkoxy _, Cr C ₁₆ perhalogenoalkyl, C ₃ -C ₇ cycloalkyl, C ₂ -Ci ₆ alkenyl, C ₅ -C ₁₄ aryl, C ₅ -C ₁₄ perhalogenoaryl, C3-12 heterocyclic, -OR ⁶ , -N0 ₂ , -COOH, -COOR ⁶ , -CONR ⁶ R ⁷ , -S0 ₂ NR ⁶ R ⁷ , -S0 ₂ R ⁶ , -CHO, -COR ⁶ , wherein R ⁶ and R ⁷ are, independently, Ci-C ₆ alkyl, CrC ₆ perhalogenoalkyl, C ₅ -C ₁₄ aryl, C ₅ -C ₁₄ perhalogenoaryl; R 2 , R 3 , R 4 and R ⁵ may be optionally linked together to form a substituted or unsubstituted, fused -C ₄ _8 carbocyclic ring _, or a substituted or unsubstituted, fused aromatic ring; Y is H, C C^ alkyl, C -C perhalogenoalkyl, C ₃ -C ₇ cycloalkyl, C ₂ -Ci ₆ alkenyl, C ₃ -C ₁₆ cycloalkenyl, CrC ₁₆ alkoxy, C ₅ -C ₁₄ aryl, C ₅ -C ₁₄ perhalogenoaryl, C3- ₁₂ heterocyclic, -COOH, -COOR ⁸ , -CONR ⁸ R ⁹ , -S0 ₂ NR ⁸ R ⁹ , -S0 ₂ R ⁸ , -CHO,

8 8 9

COR , wherein R and R are, independently, C -C alkyl, C -C perhalogenoalkyl, Cs-Cio aryl, Cs-Cio perhalogenoaryl.

In the preferred embodiment, in formula 1, substituents R ¹ , R ² , R ³ , R ⁴ and R ⁵ and Y have the meaning given above, and X is halogen, -OR ¹⁰ , -0(C=0)R ¹⁰ , -0(S0 ₂ )R ¹⁰ , wherein R ⁴ is C ₁ -C ₁₂ alkyl, C ₃ -C ₁₂ cycloalkyl, C ₅ -C ₁₄ aryl, which is optionally substituted with one or more groups selected from C -C alkyl, C -C perhalogenoalkyl, C -C alkoxy or with halogen; L ¹ is described by formula P(R') ₃ , wherein R' is C _1-12 alkyl, C _1-12 alkoxy, C ₃ _ ₁₂ cycloalkyl, C _5-12 aryl, C _5-12 aryloxy, C _5-12 heterocyclic;

L is a N-heterocyclic carbene ligand (NHC). Examples of NHC include but are not limited to compounds represented by formulas 2a-2b:

2a 2b wherein

11 12

R , are, independently, H, C C ₁₂ alkyl, C ₃ -C ₁₂ cycloalkyl, C ₅ -C ₁₄ aryl, optionally substituted with one or more groups selected from CrC ₁₂ alkyl, CrC ₁₂ perhalogenoalkyl, CrC ₁₂ alkoxy or with halogen;

R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ are, independently, H, CrC ₁₂ alkyl, C ₃ -C ₁₂ cycloalkyl, C ₂ -C ₁₂ alkenyl, C ₅ _ ₁₄ aryl, optionally substituted with one or more groups selected from

13

Q-C ₁₂ alkyl, CrC ₁₂ perhalogenoalkyl, CrC ₁₂ alkoxy or with halogen, and R , R ¹⁴ , R ¹⁵ , R ¹⁶ may be optionally linked together to form a substituted or unsubstituted, fused -C ₄ _g carbocyclic ring _> or a substituted or unsubstituted, fused aromatic ring.

Preferably, in formula 1, substituents R ¹ , R ² , R ³ , R ⁴ and R ⁵ and Y have the meaning given above, and

X is halogen, -OR ¹⁰ , -0(C=0)R ¹⁰ , -0(S0 ₂ )R ¹⁰ group, wherein R ⁴ is C ₁ -C ₁₂ alkyl, C ₃ -C ₁₂ cycloalkyl, C ₅ -C ₁₄ aryl, which is optionally substituted with one or more groups selected from C -C alkyl, C -C perhalogenoalkyl, C -C alkoxy or with halogen; I and V 2

L are described independently by formula P(R') ₃ , wherein R' is C _1-12 alkyl, C _3-12 cycloalkyl, C _5-14 aryl, C _5-12 heterocyclic, C _1-12 alkoxy, C _5-12 aryloxy.

Preferably, in formula 1,

X is CI;

R ¹ is H;

R ² , R ³ , R ⁴ and R ⁵ are, independently, H or C _1-3 alkyl;

Y is H, C ₁ -C ₁₂ alkyl, -COOH, -COOR ⁸ , -CONR ⁸ R ⁹ , -S0 ₂ NR ⁸ R ⁹ , -S0 ₂ R ⁸ , -CHO, -

8 8 9

COR , wherein R and R are, independently, C -C alkyl, Cs-Cio aryl;

L ¹ is tricyclohexylphosphine or triphenylphosphine;

L ² is a ligand of formula 2a or 2b:

_R 14 _R 15 _R 13 _R 14

R ³ R ⁶

RI I^C' 12 _R i ^{N N «} Ri2

2a 2b wherein

I I 12

R , are, independently, H, C C ₁₂ alkyl, C ₃ -C ₁₂ cycloalkyl, C ₂ -C ₁₂ alkenyl, C5-C ₁₄ aryl, optionally substituted with one or more groups selected from CrC ₆ alkyl, CrC ₆ perhalogenoalkyl, CrC ₆ alkoxy or with halogen;

R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ are, independently, H, CrC ₁₂ alkyl, C ₃ -C ₁₂ cycloalkyl, C ₂ -C ₁₂ alkenyl, C ₅ -C ₁₄ aryl, optionally substituted with one or more groups selected from CrC ₆ alkyl, CrC ₆ perhalogenoalkyl, CrC ₆ alkoxy or with halogen, and R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ may be optionally linked together to form a substituted or unsubstituted, fused -C ₄ _8 carbocyclic ring _> or a substituted or unsubstituted, fused aromatic ring.

In a preferred method, the reaction is carried out without a solvent.

Preferably, a (pre)catalyst of general formula 1 is added to dicyclopentadiene as a solution in the least amount of an organic solvent. Preferably, the organic solvent is dichloromethane or toluene.

In the preferred embodiment, polymerization is initiated by heating a mixture of dicyclopentadiene and a (pre)catalyst of general formula 1 up to a temperature of 35°C or higher.

Preferably, polymerization is carried out in the presence of a chemical activator, more preferably, the chemical activator being a Br0nsted or Lewis acid or a halogen derivative of alkane or silane, most preferably, the chemical activator being hydrogen chloride, chlorotrimethylsilane or p-toluenesulfonic acid.

In a preferred method, polymerization is carried out at a temperature within the range of 35 to 120°C.

Preferably, polymerization is carried out within the period of time ranging from 1 minute to 24 hours.

In the preferred embodiment, polymerization is carried out in the presence of an addition of an agent promoting the formation of crosslinks.

Examples of suitable agents promoting the formation of crosslinks include but are not limited to tert-butyl peroxide, di-tert-butyl peroxide and also mixtures thereof.

Preferably, the starting material contains at least 94% of DCPD.

In the preferred embodiment, polymerization is carried out using the amount of a (pre)catalyst equal to or less than 0.01 mol %.

The object of the present invention is also use of a ruthenium complex of the general formula 1

in which all substituents have the meaning as given above, to produce polydicyclopentadiene in ring-opening metathesis polymerization.

The terms relating to the groups which are not defined below shall have the broadest ordinary meaning known in the art.

The term "optionally substituted group," as used herein, means that any one or more hydrogen atoms of the group is replaced with the indicated groups, with the proviso that the substitution results in a stable compound.

The term "halogen," as used herein, means an element selected from F, CI, Br, I.

The term "carbene," as used herein, means a particle containing a neutral carbon atom of valency number being two and two unpaired valence electrons. The term "carbene" covers also carbene analogs in which a carbon atom is replaced with another chemical element; examples of such elements include but are not limited to boron, silicon, nitrogen, phosphorus, sulfur.

The term "alkyl group," as used herein, refers to a saturated linear or branched hydrocarbon substituent of the indicated number of carbon atoms. Examples of alkyl groups include but are not limited to methyl, ethyl, propyl, iso- propyl, butyl, sec-butyl, tert-butyl, pentyl.

The term "alkoxy group," as used herein, refers to an alkyl substituent as defined above connected by means of an oxygen atom. The term "perhalogenoalkyl group," as used herein, means an alkyl group as defined above where all hydrogen atoms are replaced with halogen atoms, wherein halogen atoms may be the same or different.

The term "cycloalkyl group," as used herein, refers to a saturated mono- or polycyclic hydrocarbon substituent of the indicated number of carbon atoms. The non-limiting examples of a cycloalkyl substituent are -cyclopropyl, -cyclobutyl, -cyclopentyl, -cyclohexyl.

The term "alkenyl group," as used herein, refers to a non-cyclic, linear or branched hydrocarbon chain of the indicated number of carbon atoms and containing at least one double carbon-carbon bond. The non-limiting examples of alkenyl groups are vinyl, allyl, 1-butenyl, 2-butenyl.

The term "cycloalkenyl group," as used herein, refers to an aliphatic mono- or polycyclic hydrocarbon substituent of the indicated number of carbon atoms and containing at least one double carbon-carbon bond. The non-limiting examples of a cycloalkenyl substituent are -cyclopentenyl, -cyclopentadienyl, -cyclohexenyl, -cyclohexadienyl, -cycloheptenyl, -cycloheptadienyl, -cycloheptatrienyl.

The term "aryl group," as used herein, refers to an aromatic mono- or polycyclic hydrocarbon substituent of the indicated number of carbon atoms. The non-limiting examples of an aryl group are phenyl, mesityl, anthracene.

The term "heterocyclic group", as used herein, refers to an aromatic and non- aromatic cyclic substituent of the indicated number of carbon atoms, wherein one or more carbon atoms are replaced with a heteroatom such as nitrogen, phosphorus, sulfur, oxygen with the proviso that the ring of said group does not contain two adjacent oxygen or sulfur atoms. Non-aromatic heterocyclic groups may include from 4 to 10 atoms in a ring, while aromatic heterocyclic groups must have at least 5 atoms in a ring. The heterocyclic groups include also benzo- fused ring systems. The non-limiting examples of non-aromatic heterocyclic groups are pyrrolidinyl, tetrahydrofuranyl, dihydrofuranyl, tetrahydrothienyl, tetrahydropyranyl, dihydropyranyl, tetrahydrothiopyranyl, piperidino, morpholino, thiomorpholino 2-pyrrolinyl, indolinyl. The non-limiting examples of aromatic heterocyclic groups are pyridinyl, imidazolyl, pyrimidinyl, pyrazolyl, triazolyl, pyrazinyl, furyl, thienyl. The foregoing groups may be C-attached or N- attached. For example, a substituent derived from attaching pyrrol may be pyrrol- 1-yl (N-attached) or pyrrol-3-yl (C-attached).

The term "neutral ligand," as used herein, refers to an uncharged substituent, capable of coordinating with a ruthenium atom. The non-limiting examples of neutral ligands include but are not limited to N-heterocyclic carbene ligands, amines, imines, phosphines and oxides thereof, alkyl and aryl phosphites and phosphates, ethers, alkyl and aryl sulfides, coordinated hydrocarbons, alkyl and

1 2

aryl halides. Neutral ligands L and L may be connected to a benzylidene ligand (also with a nitrogen atom forming a covalent bond with a ruthenium atom) and

1 2 they may also be combined together forming a bidentate ligand (L -L ), in addition, neutral ligands can be combined with an anionic ligand X, forming in result multidentate ligands.

The term "anionic ligand," as used herein, refers to a substituent capable of coordinating with a metallic center, having a charge capable of partial or complete compensation of a metallic center charge. The non-limiting examples of anionic ligands include but are not limited to fluoride, chloride, bromide, iodide, anions of carboxylic acids, anions of alcohols and phenols, anions of thiols and thiophenols, anions of (organo)sulfuric acids and of (organo)phosphoric acids and esters

1 2

thereof. An anionic ligand (X) and neutral ligands (L , L ) may be combined together, forming in result multidentate ligands. The non-limiting examples of multidentate ligands are a bidentate ligand (X ¹ -!. ¹ ), a tridentate ligand (X ¹ -!. ¹ - If). The non-limiting examples of neutral ligands are an acetylacetone anion and a salicylaldehyde anion.

Example I:

Preparation of polydicyclopentadiene: Dicyclopentadiene (1 g, 7.56 mmol) was introduced into a polymerization vial on air and after melting it was placed in an

011 bath of a temperature of 35°C. Then, catalyst P-2 (0.005 mol %) was added as a solution in dichloromethane and the vial was left in the bath of the same temperature for two hours. Then, toluene was added to the vial and it was brought to the boiling temperature to wash out the unreacted dicyclopentadiene. The insoluble polymer was washed with toluene and dried under reduced pressure for

12 h. Conversion of dicyclopentadiene was 83%.

Example II:

Preparation of polydicyclopentadiene: Dicyclopentadiene (1 g, 7.56 mmol) was introduced into a polymerization vial on air and after melting it was placed in an oil bath of a temperature of 35°C. Then, catalyst P-2 (0.01 mol %) was added as a solution in dichloromethane and the vial was transferred to an oil bath of a temperature of 60°C and left therein for 15 minutes. Then, toluene was added to the vial and it was brought to the boiling temperature to wash out the unreacted dicyclopentadiene. The insoluble polymer was washed with toluene and dried under reduced pressure for 12 h. Conversion of dicyclopentadiene was >99%.

Example III:

Preparation of polydicyclopentadiene: Dicyclopentadiene (1 g, 7.56 mmol) was introduced into a polymerization vial on air and after melting it was placed in an oil bath of a temperature of 35°C. Then, catalyst P-2 (0.005 mol %) was added as a solution in dichloromethane and hydrogen chloride (0.005 mol %, 4M solution in 1,4-dioxane). The vial was transferred to an oil bath of a temperature of 60°C and left therein for 25 minutes. Then, toluene was added to the vial and it was brought to the boiling temperature to wash out the unreacted dicyclopentadiene. The insoluble polymer was washed with toluene and dried under reduced pressure for 12 h. Conversion of dicyclopentadiene was >99 .

Example IV:

Preparation of polydicyclopentadiene: Dicyclopentadiene (1 g, 7.56 mmol) was introduced into a polymerization vial on air and after melting it was placed in an oil bath of a temperature of 35°C. Then, catalyst P-2 (0.005 mol %) was added as a solution in dichloromethane and chlorotrimethylsilane (TMSC1) (0.005 mol %) dissolved in a small amount of dichloromethane. The vial was transferred to an oil bath of a temperature of 60°C and left therein for 60 minutes. Then, toluene was added to the vial and it was brought to the boiling temperature to wash out the unreacted dicyclopentadiene. The insoluble polymer was washed with toluene and dried under reduced pressure for 12 h. Conversion of dicyclopentadiene was >99 .

Example V:

Preparation of polydicyclopentadiene: Dicyclopentadiene (1 g, 7.56 mmol) was introduced into a polymerization vial on air and after melting it was placed in an oil bath of a temperature of 35°C. Then, catalyst P-2 (0.005 mol %) was added as a solution in dichloromethane and p-toluenesulfonic acid (p-TsOH) (0.005 mol %) dissolved in a small amount of methanol. The vial was transferred to an oil bath of a temperature of 60°C and left therein for 30 minutes. Then, toluene was added to the vial and it was brought to the boiling temperature to wash out the unreacted dicyclopentadiene. The insoluble polymer was washed with toluene and dried under reduced pressure for 12 h. Conversion of dicyclopentadiene was >99 .

Example VI:

Preparation of polydicyclopentadiene: Dicyclopentadiene (1 g, 7.56 mmol) was introduced into a polymerization vial on air and after melting it was placed in an oil bath of a temperature of 35°C. Then, catalyst P-l (0.01 mol %) as was added a solution in dichloromethane and chlorotrimethylsilane (TMSC1) (0.01 mol %) dissolved in a small amount of dichloromethane. The vial was transferred to an oil bath of a temperature of 60°C and left therein for 120 minutes. Then, toluene was added to the vial and it was brought to the boiling temperature to wash out the unreacted dicyclopentadiene. The insoluble polymer was washed with toluene and dried under reduced pressure for 12 h. Conversion of dicyclopentadiene was >99 .

Example VII:

Preparation of polydicyclopentadiene: Dicyclopentadiene (1 g, 7.56 mmol) was introduced into a polymerization vial on air and after melting it was placed in an oil bath of a temperature of 35°C. Then, catalyst P-l (0.01 mol %) was added as a solution in dichloromethane and hydrogen chloride (0.01 mol , 4M solution in 1,4-dioxane). The vial was transferred to an oil bath of a temperature of 60°C and left therein for 120 minutes. Then, toluene was added to the vial and it was brought to the boiling temperature to wash out the unreacted dicyclopentadiene. The insoluble polymer was washed with toluene and dried under reduced pressure for 12 h. Conversion of dicyclopentadiene was 90%.

As shown in examples I- VII, complexes of formula 1 according to the invention efficiently promote ring-opening metathesis polymerization (ROMP) of dicyclopentadiene. Chemical activation of complexes of formula 1 using acids allows to easily introduce various anionic ligands to the structure of an activated complex. Some complexes of general formula 1 (such as, e.g., P-2) can also be thermally activated. The possibility of dual activation and "in situ" introduction of anionic ligands makes it possible to control precisely the start of the polymerization process as well as to control the time in which polymerization is ended. In addition, the high stability of complexes of formula 1 allows to carry out polymerization in the presence of oxygen, so there is no need to remove oxygen from the commercially available dicyclopentadiene, and it is not necessary to use an inert gas atmosphere during the process, either.