Dinuclear Nickel and Palladium Complexes with Bridging 2,5-Diamino-1,4-benzoquinonediimines: Synthesis, Structures, and Catalytic Oligomerization of Ethylene
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- 作者：Jean-philippe Taquet ; Olivier Siri ; Pierre Braunstein ; and Richard Welter
- 刊名：Inorganic Chemistry
- 出版年：2006
- 出版时间：June 12, 2006
- 年：2006
- 卷：45
- 期：12
- 页码：4668 - 4676
- 全文大小：222K
- 年卷期：v.45,no.12(June 12, 2006)
- ISSN：1520-510X
文摘
Dinuclear, divalent acetylacetonato (acac) complexes of the type [M(acac){
ntities/mgr.gif">-C6H2(ntities/bondDot.gif">NR)4}M(acac)] (M = Ni, Pd)have been prepared by the reaction of the corresponding bis(acac) metal precursor with 2,5-diamino-1,4-benzoquinonediimines C6H2(NHR)2(=NR)2 (4a, R = CH2-t-Bu; 4b, R = CH2Ph; 4c, R = Ph), which are metalatedand become bridging ligands, also like in the complex [(C8H11)Pt{ntities/mgr.gif">-C6H2(ntities/bondDot.gif">NCH2-t-Bu)4}Pt(C8H11)] (6) obtainedby the reaction of 4a with [PtCl2(COD)]. The complexes were fully characterized, including by X-ray diffraction for[Ni(acac){ntities/mgr.gif">-C6H2(ntities/bondDot.gif">NCH2Ph)4}Ni(acac)] (9b) and [Pd(acac){ntities/mgr.gif">-C6H2(ntities/bondDot.gif">NCH2-t-Bu)4}Pd(acac)] (10a). The coordination geometry around the metal ions is square-planar, and a complete electronic delocalization of the quinonoid 
system occurs between the metal centers over the two Nntities/bondDot.gif">Cntities/bondDot.gif">Cntities/bondDot.gif">Cntities/bondDot.gif">N halves of the ligand. The nature of theN substituent explains the differences between the supramolecular stacking arrangements found for [Ni(acac){ntities/mgr.gif">-C6H2(ntities/bondDot.gif">NR)4}Ni(acac)] (9a; R = CH2-t-Bu; 9b, R = CH2Ph). The Ni complexes were evaluated as catalyst precursorsfor ethylene oligomerization in the presence of AlEtCl2 or MAO as the cocatalyst, in particular in order to studypossible cooperative effects resulting from electronic communication between the metal centers and to examinethe influence of the N substituent on the activity and selectivity. These catalysts afforded mostly ethylene dimersand trimers.
ntities/mgr.gif">-C6H2(ntities/bondDot.gif">NR)4}M(acac)] (M = Ni, Pd)have been prepared by the reaction of the corresponding bis(acac) metal precursor with 2,5-diamino-1,4-benzoquinonediimines C6H2(NHR)2(=NR)2 (4a, R = CH2-t-Bu; 4b, R = CH2Ph; 4c, R = Ph), which are metalatedand become bridging ligands, also like in the complex [(C8H11)Pt{ntities/mgr.gif">-C6H2(ntities/bondDot.gif">NCH2-t-Bu)4}Pt(C8H11)] (6) obtainedby the reaction of 4a with [PtCl2(COD)]. The complexes were fully characterized, including by X-ray diffraction for[Ni(acac){ntities/mgr.gif">-C6H2(ntities/bondDot.gif">NCH2Ph)4}Ni(acac)] (9b) and [Pd(acac){ntities/mgr.gif">-C6H2(ntities/bondDot.gif">NCH2-t-Bu)4}Pd(acac)] (10a). The coordination geometry around the metal ions is square-planar, and a complete electronic delocalization of the quinonoid system occurs between the metal centers over the two Nntities/bondDot.gif">Cntities/bondDot.gif">Cntities/bondDot.gif">Cntities/bondDot.gif">N halves of the ligand. The nature of theN substituent explains the differences between the supramolecular stacking arrangements found for [Ni(acac){ntities/mgr.gif">-C6H2(ntities/bondDot.gif">NR)4}Ni(acac)] (9a; R = CH2-t-Bu; 9b, R = CH2Ph). The Ni complexes were evaluated as catalyst precursorsfor ethylene oligomerization in the presence of AlEtCl2 or MAO as the cocatalyst, in particular in order to studypossible cooperative effects resulting from electronic communication between the metal centers and to examinethe influence of the N substituent on the activity and selectivity. These catalysts afforded mostly ethylene dimersand trimers.