Zirconium complexes with cyclopentadienyl Ligands involving fused a thiophene fragmentстатья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.
Аннотация:The following cyclopentadienes (Cp'H) with fused thiophene and benzothiophene fragments were synthesized: 4,5-dimethyl-6H-cyclopenta[b]thiophene(2),5,6-dimethyl-4H-cyclopenta[b]t hiophene (4), 1,3,5-trimethyl-4H-cyclopenta[c]thiophene (6), 2-methyl-1(and 3)H-cyclopenta[b][1]thiophenes(9),2,3-dimethyl-1H-cyclopenta[b][l]benzot hiophene(11),1,2-dimethyl-3H-cyclopenta[b] [1]benzothiophene (14). After a deprotonation of 2, 4, 11, and 14 with n-BuLi, followed by treatment of the resulting lithium salts with (eta(5)-C5Me5)ZrCl3, complexes (eta(5)-Cp')(eta(5)-C5Me5)ZrCl2 were obtained. The ligand 6 gave a mixture of undesirable products instead of the respective metallocene. Two of them were isolated and turned out to be the polynuclear hydride complex {(Cp*Zr)(mu-H)(mu-Cl)(2)(Cp*ZrCl)}(2)(mu-Cl)(6)Li-2 and a binuclear complex containing an unusual bridged bis[1,5-dimethyl-3-methylene-1,3-dihydro-eta(5)-cyclopenta[c]thien-1-yl] ligand. Starting from the cyclopentadienes 2, 4, 11, and 14, several bis(cyclopentadienyl)dimethylsilanes were obtained and further used for the synthesis of the respective ansa-zirconocenes, which were isolated and unambiguously characterized either as pure diastereomeres or as rac/meso mixtures. Unbridged complex Cp'2ZrCl2 was prepared in a similar manner from the ligand 9.