Synthesis and catalytic properties of oxalic amidinato complexes

摘要

The oxalic amidine compounds C_6H_5N=C(NH~tBu)-C(NH~tBu)=NC_6H_5 1 and C_6H_5N=C{N(~tBu)(SiMe_3)}-C{N(~tBu)(SiMe_3)}=NC_6H_5 2 are described. The compuond [(C_6H_5N)C(NH~tBu)-C(NH~tBu)(NHC_6H_5)][Br] 3~* has been isolated from the raction between 1 and [NiBr_2(DME)]. Treatment of 1 with M(NMe_2)_4 (M = Zr or Ti), [Ta(NEt_2)_2Cl_3(py)] or [Zr{N(SiMe_3)_2}_3Cl] gives the bimetallic complexes [M(NMe_2)_3(C_6H_5N)C(N~tBu)-]_2 (M = Zr (4) or M = Ti (5)) and the mono-amidinato complexes [Ta(NEt_2)Cl_3{(C_6H_5N)C(NH~tBu)C(NH~tBu)(NC_6H_5)}] 6~* and [Zr{N(SiMe_3)_2}_2Cl{(C_6H_5N)C(NH~tBu)C(NH~tBu)(NC_6H_5)}] 7~* respectively: * indicates the crystal the crystal structure has been determined. The activity toward ethylene polymrisation has been investigated for compounds 4,5 and 7