| abstract |
Vanadium phosphinic complex having general formula (I) or (II): n V(X) 3 [P(R 1 ) n (R 2 ) 3-n ] 2 (I)n n V(X) 3 [(R 3 ) 2 P(R 4 )P(R 3 ) 2 ] (II)n wherein: X represents an anion selected from halogens such as, for example, chlorine, bromine, iodine, preferably chlorine; or is selected from the following groups: thiocyanate, isocyanate, sulfate, acid sulfate, phosphate, acid phosphate, carboxylate, dicarboxylate; R 1 , identical or different among them, represent a hydrogen atom, or an allyl group (CH 2 ═CH—CH 2 —); or are selected from alkyl groups C 1 -C 20 , preferably C 1 -C 15 , linear or branched, optionally halogenated, optionally substituted cycloalkyl groups; n is an integer ranging from 0 to 3; R 2 , identical or different among them, are selected from optionally substituted aryl groups; R 3 , identical or different among them, represent a hydrogen atom, or an allyl group (CH 2 ═CH—CH 2 —); or are selected from alkyl groups C 1 -C 20 , preferably C 1 -C 15 , linear or branched, optionally halogenated, optionally substituted cycloalkyl groups, optionally substituted aryl groups; R 4 represents a group —NR 5 wherein R 5 represents a hydrogen atom, or is selected from C 1 -C 20 alkyl groups, preferably C 1 -C 15 , linear or branched; or R 4 represents an alkylene group —(CH 2 ) p- wherein p represents an integer ranging from 1 to 5; provided that in the general formula (I), in case n is equal to 1 and R 1 is methyl, R 2 is different from phenyl. nn Said phosphinic vanadium complex having general formula (I) or (II) can be advantageously used in a catalytic system for the (co)polymerization of conjugated dienes. |