Ruthenium-based complexes, their preparation and use as catalysts

1. A ruthenium-based complex according to general formula (I)

wherein:

X 1 represents an anionic ligand;

Y is O or S;

R 1 is substituted or unsubstituted C 6 -C 14 -aryl, an N-heterocyclic carbene ligand or P(R′) 3 with R′ being identical or different and representing either substituted or unsubstituted, straight chain or branched C 1 -C 14 alkyl, substituted or unsubstituted C 6 -C 24 aryl, or substituted or unsubstituted C 3 -C 20 cycloalkyl;

R represents substituted or unsubstituted, straight chain or branched C 1 -C 14 -alkyl;

L 2 represents a ligand having the general structure (Ia*) or (Ib*)

or a ligand having the general structure (Ic*) or (Id*)

in which formulae (Ia*), (Ib*), (Ic*) and (Id*)

n is identical or different and represents an integer in the range of from 1 to 20,

D is identical or different and represents hydroxy, alkoxy, aryloxy, thiol, thiolate, thioether, selenol, selenoether, amine, phosphine, phosphate, phosphite, arsine, sulfoxide, sulfone, alkyl, phosphinimine, aminophosphine, carbene, selenoxide, imidazoline, imidazolidine, phosphine oxide, phosphine sulfide, phosphine selenide, ketone, ester, pyridyl, substituted pyridyl or any moiety able of acting as a two electron donor;

R 3 is identical or different and represents H, alkyl or aryl;

E is identical or different and represents a divalent moiety capable of acting as a two electron donor selected from the group consisting of —O—, —S—, —Se—, —N(R)—, —P(R)—, —As(R)—, —S(═O)—, —PR(═S)—, —PR(═O)—, —C(═O)—, —C(═S)—, 2,6-pyridylene, substituted 2,6-pyridylene, and any other divalent moiety capable of acting as a two electron donor; and

R 2 are identical or different in a respective moiety (Ia*), (Ib*), (Ic*) or (Id*) and represent H, alkyl, aryl, halide, or in the alternative two R 2 together with the two adjacent carbon atoms to which they are bound in a moiety (Ia*), (Ib*), (Ic*) or (Id*) form a fused-on five- or six-membered saturated or unsaturated ring; and

L 1 is an N-heterocyclic carbene ligand which is different from general structures (Ia*), (Ib*), (Ic*), and (Id*).

2. The ruthenium-based complex according to claim 1 , wherein X 1 is halide, pseudohalide, alkoxide, amide, triflate, phosphate, borate, carboxylate, acetate, halogenated acetate, halogenated alkylsulfonate, tosylate, any weakly coordinating anionic ligands, straight-chain or branched C 1 -C 30 -alkyl or C 6 -C 24 -aryl.

3. The ruthenium-based complex according to claim 1 , wherein L 1 represents an imidazoline or imidazolidine ligand having a structure corresponding to the general formulae (IIa), or (IIb),

wherein under the proviso that L 1 is different from the general formulae (Ia*), (Ib*), (Ic*) and (Id*),

R 4 , R 5 , R 6 , R 7 are identical or different and are each hydrogen, straight-chain or branched C 1 -C 30 -alkyl, C 3 -C 20 -cycloalkyl, C 2 -C 20 -alkenyl, C 2 -C 20 -alkynyl, C 6 -C 24 -aryl, C 1 -C 20 -carboxylate, C 1 -C 20 -alkoxy, C 2 -C 20 -alkenyloxy, C 2 -C 20 -alkynyloxy, C 6 -C 20 -aryloxy, C 2 -C 20 -alkoxycarbonyl, C 1 -C 20 -alkylthio, C 6 -C 20 -arylthio, C 1 -C 20 -alkylsulphonyl, C 1 -C 20 -alkylsulphonate, C 1 -C 20 -arylsulphonate or C 1 -C 20 -alkylsulphinyl

or in the alternative

R 6 and R 7 have the above mentioned meanings and at the same time R 4 and R 5 jointly form a C 6 -C 10 cyclic structure together with the two adjacent carbon atoms in the imidazoline or imidazolidine ring,

the meanings of the substituents R 4 , R 5 , R 6 , R 7 are either unsubstituted or substituted by one or more substituents.

4. The ruthenium-based complex according to claim 3 , wherein the imidazoline or imidazolidine ligand has the following structures (III-a) to (III-o), where Ph is in each case a phenyl substituent, Bu is any type of butyl substituent, Mes is in each case a 2,4,6-trimethylphenyl substituent and (iPr) 2 Ph is in all cases 2,6-diisopropylphenyl

5. The ruthenium-based complex according to claim 1 , wherein R 1 represents unsubstituted C 6 -C 14 -aryl or C 6 -C 14 -aryl being substituted with 1, 2, 3, 4, 5 or more substituents selected from the group consisting of F, Cl, Br, I, NO 2 , and CH 3 .

6. The ruthenium-based complex according to claim 1 , wherein R represents straight chain or branched, substituted or unsubstituted C 1 -C 8 -alkyl.

7. The ruthenium-based complex according to claim 1 , wherein:

X 1 represents halide, phosphate, borate, carboxylate, acetate, trifluoroacetate, trifluoromethylsulfonate or tosylate;

Y is O or S;

R 1 represents unsubstituted C 6 -C 14 -aryl or C 6 -C 14 -aryl being substituted with 1, 2, 3, 4, 5 or more substituents selected from the group consisting of F, Cl, Br, I, NO 2 , and CH 3 ;

R represents unsubstituted, straight chain or branched C 1 -C 5 -alkyl or a straight chain or branched C 1 -C 5 -alkyl which is substituted by C 6 -C 14 -aryl;

L 1 represents an imidazoline or imidazolidine ligand having a structure corresponding to the general formulae (IIa), or (IIb),

wherein under the proviso that L 1 is different from the general formulae (Ia*), (Ib*), (Ic*) and (Id*) as defined for L 2 ,

R 4 , R 5 , R 6 , R 7 are identical or different and are each hydrogen, straight-chain or branched C 1 -C 30 -alkyl, C 3 -C 20 -cycloalkyl, C 2 -C 20 -alkenyl, C 2 -C 20 -alkynyl, C 6 -C 24 -aryl, C 1 -C 20 -carboxylate, C 1 -C 20 -alkoxy, C 2 -C 20 -alkenyloxy, C 2 -C 20 -alkynyloxy, C 6 -C 20 -aryloxy, C 2 -C 20 -alkoxycarbonyl, C 1 -C 20 -alkylthio, C 6 -C 20 -arylthio, C 1 -C 20 -alkylsulphonyl, C 1 -C 20 -alkylsulphonate, C 6 -C 20 -arylsulphonate or C 1 -C 20 -alkylsulphinyl

or in the alternative

R 6 , R 7 have the above mentioned meanings and at the same time R 4 and R 5 jointly form a C 6 -C 10 cyclic structure together with the two adjacent carbon atoms in the imidazoline or imidazolidine ring; and

L 2 represents either a ligand of the structure (Ia*) or (Ib*) in which

n is identical or different and represents an integer of 1 to 5, and

D is identical or different and represents C 1 -C 10 -alkoxy or C 6 -C 14 -aryloxy,

or

a ligand of the structure (Ic*) or (Id*) in which

n is identical or different and represents an integer of 1 to 5; and

E is identical or different and represents oxygen or sulfur; and

R 3 is identical or different and represents C 1 -C 10 alkyl or C 6 -C 14 aryl, wherein all aforementioned can be unsubstituted or substituted by one or more substituents,

with

R 2 being identical or different in a respective moiety (Ia*), (Ib*), (Ic*) or (Id*) and representing H, C 1 -C 10 -alkyl, C 6 -C 14 -aryl, halide, or in the alternative two R 2 together with the two adjacent carbon atoms to which they are bound in a moiety (Ia*), (Ib*), (Ic*) or (Id*) form a fused-on five- or six-membered saturated or unsaturated ring.

8. The ruthenium-based complex according to claim 1 , wherein the complex has the structure of formulae (I-1) to (I-10)

9. A catalyst system comprising at least one ruthenium-based complex of the general formula (I) according to claim 1 and at least one Lewis acid.

10. A process for preparing the ruthenium-based complexes of general formula (I) according to claim 1 , the process comprising:

reacting a compound of general formula (IV)

in which

L 2 means a ligand having the general structure (Ia*) or (Ib*)

or a ligand having the general structure (Ic*) or (Id*)

in which formulae (Ia*), (Ib*), (Ic*) and (Id*)

n is identical or different and represents an integer in the range of from 1 to 20;

D is identical or different and represents hydroxy, alkoxy, aryloxy, thiol, thiolate, thioether, selenol, selenoether, amine, phosphine, phosphate, phosphite, arsine, sulfoxide, sulfone, alkyl, phosphinimine, aminophosphine, carbene, selenoxide, imidazoline, imidazolidine, phosphine oxide, phosphine sulfide, phosphine selenide, ketone, ester, pyridyl, substituted pyridyl or any moiety able of acting as a two electron donor;

R 3 is identical or different and represents H, alkyl or aryl;

E is identical or different and represents a divalent moiety able of acting as a two electron donor selected from the group consisting of —O—, —S—, —Se—, —N(R)—, —P(R)—, —As(R)—, —S(═O)—, —PR(═S)—, —PR(═O)—, —C(═O)—, —C(═S)—, 2,6-pyridylene, substituted 2,6-pyridylene and any other divalent moiety able of acting as a two electron donor; and

R 2 are identical or different in a respective moiety (Ia*), (Ib*), (Ic*) or (Id*) and represent H, alkyl, aryl, halide, or in the alternative two R 2 together with the two adjacent carbon atoms to which they are bound in a moiety (Ia*), (Ib*), (Ic*) or (Id*) form a fused-on five- or six-membered saturated or unsaturated ring;

L 1 is a N-heterocyclic carbene ligand which is different from general structures (Ia*), (Ib*), (Ic*), and (Id*); and

L 3 represents P(R′) 3 with R′ being identical or different and representing either substituted or unsubstituted, straight chain or branched C 1 -C 14 alkyl, substituted or unsubstituted C 6 -C 24 aryl, or substituted or unsubstituted C 3 -C 20 cycloalkyl,

with a compound of general formula (V)

in which Y and R 1 have the same meanings as defined with regard to formula (I), It produce a compound of general formula (VI)

in which L 1 , L 2 , R 1 , Y and R have the same meanings as defined with regard to formula (I), and

converting the compound of the general formula (VI) with

(CH 3 ) 3 SiX 2

in which X 2 has the same meaning as defined with regard to formula (I) to produce the ruthenium-based complexes of general formula (I).

11. A method of catalysing metathesis reactions, the method comprising contacting C═C double bond containing substrates with at least one ruthenium-based complex according to claim 1 for ring-closing metatheses (RCM), cross metatheses (CM) or ring-opening methatheses (ROMP).

12. The method according to claim 11 , wherein:

the substrates are nitrile rubbers being copolymers or terpolymers comprising repeating units of at least one conjugated diene, at least one α,β-unsaturated nitrile monomer, and none, one or more further copolymerizable monomers; and

the method further comprises using the ruthenium-based complex together with at least one Lewis acid, of the general formula (Z)

B(R 8 ) 3   (Z)

wherein

R 8 are identical or different and are halogen, unsubstituted or substituted C 6 -C 14 -aryl, or unsubstituted or substituted C 6 -C 14 -heteroaryl radicals, wherein at least one of the 6 to 14 C-atoms is replaced by one heteroatom.

13. A process for producing compounds, the process comprising subjecting at least one substrate containing at least one C═C double bond to a metathesis reaction in the presence of the Ruthenium complex according to claim 1 .

14. The process for producing compounds according to claim 13 , wherein the compounds are nitrile rubbers with a weight average molecular weight M w ′, and the substrate is a starting nitrile rubber having a weight average molecular weight M w , and the process comprises subjecting the starting nitrile rubber having a weight average molecular weight M w to a cross-metathesis reaction in the presence of the Ruthenium-based complex to metathesize the nitrile rubber and produce the nitrile rubbers with the weight average molecular weight M w ′, wherein the weight average molecular weight M w of the starting nitrile rubber M w is higher than the weight average molecular weight M w ′ of the nitrile rubber prepared.

15. The process according to claim 14 , further comprising mixing the ruthenium complex of general formula (I) and the substrate(s) in a molar ratio of 1:226 to 1:2.5.

16. The process according to claim 14 wherein the amount of ruthenium complex of general formula (I) is 0.005 to 0.25 phr, wherein phr means parts by weight per 100 parts by weight of the nitrile rubber to be degraded.

17. The catalyst system according to claim 9 , wherein the at least one Lewis acid comprises at least one compound of the general formula (Z)

B(R 8 ) 3   (Z)

wherein

R 8 are identical or different and are halogen, unsubstituted or substituted C 6 -C 14 -aryl, or unsubstituted or substituted C 6 -C 14 -heteroaryl radicals, wherein at least one of the 6 to 14 C-atoms is replaced by one heteroatom.

18. The catalyst system according to claim 9 , wherein the at least one Lewis acid is at least one of BCl 3 , BF 3 , Bl 3 , and B(C 6 F 5 ) 3 .