Tridentate-linked amido-cyclopentadienyl ligands C(5)Me(4)SiMe(2)NCH(2)R with a neutral donor site R (R = CH(2)OMe CH(2)NMe(2), CH=CH2) have been. synthesized and coordinated at tetravalent titanium and zirconium centers. The molecular structure of Zr(eta(5):eta(1): eta(1)-C(5)Me(4)SiMe(2)NCH(2)CH(2)NMe(2))Cl-2 (4b) was determined by a single-crystal X-ray structural analysis, revealing an unusual trigonal-bipyramidal zirconium center with the CH(2)CH(2)NMe(2) moiety interacting with the zirconium center.
M−Cl/Si−Cl Preferential Reactivity in Chlorosilyl-Substituted Cyclopentadienyl Early Transition Metal Complexes in Reactions with Amines: Key to Understanding the Nature of the Final Product
作者:Cristina Paniagua、Marta E. G. Mosquera、Heiko Jacobsen、Gerardo Jiménez、Tomás Cuenca
DOI:10.1021/om9008026
日期:2009.12.28
The reaction of [Ti(eta(5)-C5Me4SiMe2Cl)Cl-3] (1) with 1 equiv of different ethylenediamines, NHR-(CH2)(2)NR'R '', regiospecifically affords cyclopentadienyl-silyl-amido derivatives with constrained geometry, [Tieta(5)-C5Me4SiMe2-kappa-N(CH2)(2)NR'R ''}Cl-2] (R' = R '' = H, 2a; R' = H, R '' = Me, 2b; R' = R" = Me, 2c) or unstrained structure, [Tieta(5)-C5Me4SiMe2NMe(CH)(2)-kappa-NMe)Cl-2] (3). Treatment of 1 with 1.5 equiv of ethylenediamine gives a mixture of 2a and the transient complex [Tieta(5)-C5Me4SiMe2NH(CH2)(2)NH2}Cl-3] (4), which is transformed into 2a upon addition of a base. The reaction of 1 with N,N,N'-trimethylethylenediamine permits the synthesis and isolation of the complex [Tieta(5)-C5Me4SiMe2NMe(CH2)(2)NMe2]Cl-3](5). Compound 1 reacts with 0.5 equiv of NH2(CH2)(2)NH2 to yield a mixture of 2a along with the tethered dinuclear cyclopentadienyl-silyl-amido compound [Tieta(5)-C5Me4SiMe2-kappa-N(CH2)-} Cl-2](2) (6).