Ruthenium complexes and their use in olefin metathesis reactions

A ruthenium complex of formula 1

• wherein:
• X1, X2 are each independently an anionic ligand selected from such as halogen atom, —OR, —SR, —C(C═O)R, where R is C1-C12 alkyl, C3-C12 cycloalkyl, C2-C12 alkenyl, C5-C20 aryl, which are optionally substituted with at least one C1-C12 alkyl, optionally C1-C12 perhalogenalkyl, optionally C1-C12 alkoxy, optionally a halogen atom;
• R1 is a hydrogen atom or C5-C24 aryl, C1-C25 alkyl, C5-C25 heteroaryl, C7-C24 aralkyl, which are optionally substituted by at least one C1-C12 alkyl, optionally C1-C12 perhalogenalkyl, optionally C1-C12 alkoxy, optionally a halogen atom, wherein the alkyl groups may be interconnected to form a ring;
• R2 is C5-C24 aryl, C5-C25 heteroaryl, C7-C24 aralkyl, which are optionally substituted by at least one C1-C12 alkyl, optionally C1-C12 perhalogenalkyl, optionally C1-C12 alkoxy, optionally a halogen atom, wherein the alkyl groups may be interconnected to form a ring;
• R3 is C1-C12 alkyl, C3-C12 cycloalkyl, C5-C20 aryl, or C5-C20 heteroaryl, which is optionally substituted by at least one C1-C12 alkyl, C1-C12 perhalogenalkyl, C2-C12 alkoxy or a halogen atom;
• R4, R5, R6, R7, R8, R9 are each independently a hydrogen atom, C1-C12 alkyl, C3-C12 cycloalkyl, C5-C20 aryl, or C5-C20 heteroaryl, which is optionally substituted by at least one C1-C12 alkyl, C1-C12 perhalogenalkyl, C1-C12 alkoxy or a halogen atom, and the R4 and R5 and/or R8 and R9 groups may optionally be interconnected to form a cyclic system C4-C10;
• and
• a, b, c, d—are each independently a hydrogen atom, a halogen atom, C1-C25 alkyl, C1-C25 perfluoroalkyl, C3-C7 cycloalkyl, C1-C25 alkoxy, C5-C24 aryl, C7-C24 aralkyl, C5-C25 heteroaryl, 3-12-membered heterocycle, wherein the alkyl groups may be interconnected to form a ring;
• also, each of them can be independently an ether (—OR′), thioether (—SR′), nitro (—NO2), cyano (—CN), amide (—CONR′R″), carboxy and ester (—COOR′), sulfa (—SO2R′), sulfonamide (SO2NR′R″), formyl and ketone (—COR′) group, in which groups R′ and R″ are each C1-C25 alkyl, C1-C25 perfluoroalkyl, C5-C24 aryl, C5-C25 heteroaryl, C5-C24 perfluoroaryl.