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Expanding Heteroscorpionates. Facile Synthesis of New Hybrid Scorpionate/Cyclopentadienyl Ligands and Their Lithium and Group 4 Metal Compounds: A Combined Experimental and Density Functional Theory Study

2007; American Chemical Society; Volume: 26; Issue: 17 Linguagem: Inglês

10.1021/om7003942

1520-6041

Antonío Otero, Juan Fernández‐Baeza, Antonío Antiñolo, Juan Tejeda, Agustín Lara‐Sánchez, Luis F. Sánchez‐Barba, Margarita Sánchez‐Molina, Ana M. Rodrı́guez, Carles Bó, Manuel Urbano‐Cuadrado,

Ferrocene Chemistry and Applications

The preparation of new hybrid scorpionate/cyclopentadienyl ligands in the form of the lithium derivatives [Li(bpzcp)(THF)] (1) [bpzcp = 2,2-bis(3,5-dimethylpyrazol-1-yl)-1,1-diphenylethylcyclopentadienyl] and [Li(bpztcp)(THF)] (2) [bpztcp = 2,2-bis(3,5-dimethylpyrazol-1-yl)-1-tert-butylethylcyclopentadienyl] or as a mixture of the two scorpionate/cyclopentadiene regioisomers (bpzpcpH) 1-[2,2-bis(3,5-dimethylpyrazol-1-yl)-1-phenylethyl]-1,3-cyclopentadiene (3a) and 2-[2,2-bis(3,5-dimethylpyrazol-1-yl)-1-phenylethyl]-1,3-cyclopentadiene (3b) has been carried out by reaction of bis(3,5-dimethylpyrazol-1-yl)methane (bdmpzm) with BunLi and 6,6-diphenylfulvene, 6-tert-butylfulvene, or 6-phenylfulvene, respectively. However, when this insertion reaction was carried out with 6,6-dimethylfulvene, the compound [Li(isoprcp)(bdmpzm)(THF)] (4) [isoprcp = isopropenylcyclopentadienyl] was obtained. Compounds 1 and 2 reacted with [TiCl4(THF)2] or [MCl4] (M = Zr, Hf) to give the complexes [MCl3(bpzcp)] (M = Ti, 5; Zr, 6; Hf, 7) and [MCl3(bpztcp)] (M = Ti, 8; Zr, 9; Hf, 10). Similar reactions do not take place with the mixture of the two isomers 3a and 3b. However, when a THF solution of 3a−3b and [MCl4] (M = Zr, Hf) was heated under reflux, the complexes [MCl3(bpzpcp)] (M = Zr, 11; Hf, 12) [bpzpcp = 2,2-bis(3,5-dimethylpyrazol-1-yl)-1-phenylethylcyclopentadienyl] were obtained. In addition, alkyl complexes [ZrClMe2(bpztcp)] (13) and [ZrMe3(bpztcp)] (14) were also prepared. The structures of these complexes have been determined by spectroscopic and DFT methods, and in addition, the X-ray crystal structures of 1, 2, 3b, and 6 were also established.