| 摘要註: |
將N,N,N三牙配位基1,8-bis(alkylimino)-3,6-di-tert-butyl-9H-carbazole (3a, 3b, 3c)的氮三牙配位基,與二甲基鋅錯化形成 [1,8-bis(phenylimino)-3,6-di-tert-butyl-carbazolide]-ZnCH3 (4a)、[1,8-bis(n-hexylimino)-3,6-di-tert-butyl-carbazolide]-ZnCH3 (4b)、 [1,8-bis(cyclo-hexylimino)-3,6-di-tert-butyl-carbazolide]-ZnCH3 (4c)。化合物4b可與另一當量的配位基分子形成雙配位基化合物 4d,也可以加入二甲基鋅將4d反應回4b,但是4a與4c卻不會有類似的反應發生。由X-ray單晶繞射的結果中得知,4b的中心鋅金屬是一個扭曲的四面體結構,而4d的中心鋅金屬則是一個八面體結構,其造成的原因可能是因為正己基具有彈性。初步測試的結果,所有的鋅錯化物對於ɛ-己內酯都具有聚合的活性。將1,8-di-acetyl-3,6-di-tert-butyl-carbazole (2) 還原會生成1, 8-di-ol的立體異構物5,並藉由X-ray單晶繞射分別證實外消旋混和物及內消旋產物可以分離。純的光學異構物也可以藉由對掌性管住層析分離,這些[O-,N-,O-]螯合型配位基是具有與異丙醇鈦進行錯化反應的潛力。 Complexation of dimethyl zinc and the N,N,N tridentate ligands, 1,8-bis(alkylimino)-3,6-di-tert-butyl-9H-carbazole (3a, 3b, 3c), gives [1,8-bis(phenylimino)-3,6-di-tert-butylcarbazolide]-Zn(CH3) (4a), [1,8-bis(n-hexylimino)-3,6-di-tert-butylcarbazolide]-Zn(CH3) (4b) and [1,8-bis(cyclo-hexylimino)-3,6-di-tert-butylcarbazolide]-Zn(CH3) (4c). Compound 4b reacts with another equivalent ligand to yield bis-ligated compound, 4d, which may be back to 4b by the reaction with dimethyl zinc. However, no similar reaction was observed in the cases of 4a and 4c By X-ray diffraction crystallography, the zinc center has distorted tetrahedral geometry in 4b, and has octahedral geometry in 4d. This might result from readily flexibility of the n-hexyl group. The preliminary study shows that all the zinc complexes are active toward the polymerization of ɛ-caprolactone.Reduction of 1,8-di-acetyl-3,6-di-tert-butyl-carbazole (2) gives the 1, 8-di-ol stereo isomers, 5. The racemic mixtures and meso-form can be separated and confirmed by X-ray diffraction crystallography, respectively. The pure optical isomers can be isolated by chiral column chromatography. These [O-,N-,O-]-pincer type ligands are potentially able to complex with titanium isopropoxide. |