Syntheses and Structural Studies of the Coupling Products of the Zr(6,6-dimethylcyclohexadienyl)2 Fragment with the Diimines (CH2)n[N=CH(C6H5)]2 (n = 3,4)

The reactions of the α,ω-diimines (CH2) n [N=CH(C6H5)]2 with Zr(6,6-dmch)2(PMe3)2 (dmch = dimethylcyclohexadienyl) lead to couplings of both imine carbon atoms, each to one of a single dmch ligand’s termini, which thereby also leads to the formation of two Zr–N bonds, and release of the phosphine ligands. The resulting complexes possess 18 electron configurations by virtue of a remaining η5-6,6-dmch ligand, η3-allyl coordination by the coupled 6,6-dmch ligand, and π-amide coordination by each nitrogen donor center. The η5-6,6-dmch ligand displays the distortions expected for a high valent metal pentadienyl complex. The n = 3 complex crystallized in the monoclinic space group P21/c with a = 8.5687(2) A, b = 27.8768(6) A, c = 11.7747(3) A, β = 103.6081(8)°, V = 2,733.64(11) A3, Dcalc = 1.351 g/cm3 at 150(1) K. For the n = 4 complex, the triclinic space group P $$ \overline{1} $$ is adopted, with a = 11.1279(3) A, b = 11.3846(3) A, c = 14.9154(3) A, α = 81.6030(13)°, β = 69.8503(13)°, γ = 84.6588(12)°, V = 1,753.05(7) A3, Dcalc = 1.283 g cm−3 at 150(1) K. The reactions of the Zr(6,6-dimethylcyclohexadienyl)2 fragment with α,ω-diimines (CH2) n [N=CH(C6H5)]2 led to couplings between the imine carbon atoms and the dienyl termini, thereby resulting in 12- and 13-membered ring constructions.