Air-stable ni(0)-olefin complexes and their use as catalysts or precatalysts

Process for preparing an air-stable Ni(R)3—complex wherein Ni represents Ni(0) and R are the same or different and represents a trans-stilbene of the Formula (I):

• wherein in Formula (I), R3 and R8 are the same or different and are selected from C1 to C8 perfluoro alkyl and the others of R1 to R10 are hydrogen, and R11 to R12 may be the same or different and are selected from H, C1 to C6 alkyl, O—C1 to C6 alkyl, C3 to C6 cycloalkyl, or —O—C3 to C6 cycloalkyl;
• or,
• wherein in Formula (I), R3 and R8 are each C1 to C8 perfluoro alkyl and the others of R1 to R10 and R11 to R12 are hydrogen;
• or,
• wherein in Formula (I), R3 and R8 are each —CF3, and the others of R1 to R10 and R11 to R12 are hydrogen,
• said process comprising reacting a Nickel (II) compound, selected from NiF2, NiCl2, NiBr2, NiI2, Ni(OTf)2, Ni(BF4)2, Ni(OTs)2, Ni(glyme)Cl2, Ni(glyme)Br2, Ni(diglyme)Cl2, Ni(diglyme)Br2, Ni(NO3)2, Ni(OR13)2 (where R13 represents-C(O)—C1-C6-alkyl which is optionally substituted with one of more halogen), Ni(acetyl acetonate)2, Ni(Ac)2, or mixtures thereof, with at least three equivalents of the trans-stilbene of Formula (I) in the presence of at least two equivalents of an aluminum alkyl of the Formula Al(R14)3, wherein R14 may be the same or different and is selected from C1 to C6 alkyl or C3 to C6 cycloalkyl.