Lewis acids <i>in situ</i> modulate pyridazine-imine Ni catalysed ethylene (co)polymerisation
作者:Guohong Wang、Min Li、Wenmin Pang、Min Chen、Chen Tan
DOI:10.1039/c9nj01243e
日期:——
copolymerisation of ethylene with methyl 10-undecenoate, both catalytic activity and the polar monomer incorporation ratio (up to 2.0%) increased upon using B(III) Lewisacidic additives. It was indicated that the Lewis acid–base interaction between B(III) Lewisacids and the pyridazine moiety reduced the electron density from the Ni center and in situ modulated the pyridazine-imine Ni catalyzed ethylene (co)polymerisation
路易斯酸原位调节在烯烃聚合中起重要作用。在这项工作中,哒嗪-亚胺Ni络合物Ni1和Ni2已在乙烯(共)聚合反应中合成,表征和研究。在乙烯的均聚中,B(III)Lewis酸性添加剂导致催化活性增加(最高为19.2×10 5 g mol Ni -1 h -1)。此外,B(IIILewis酸性添加剂可以调节聚乙烯产品的微观结构,从而增加支化密度和长链分支。在乙烯与10-十一碳烯酸甲酯的共聚中,使用B(III)Lewis酸性添加剂可提高催化活性和极性单体的掺入率(最高2.0%)。研究表明,B(III)路易斯酸与哒嗪部分之间的路易斯酸-碱相互作用降低了Ni中心的电子密度,并原位调节了哒嗪-亚胺Ni催化的乙烯(共)聚合。
Redox rich dicobalt macrocycles as templates for multi-electron transformations
作者:Nathaniel K. Szymczak、Louise A. Berben、Jonas C. Peters
DOI:10.1039/b913946j
日期:——
Pyridazine-templated dicobalt macrocycles reversibly support five oxidation states with unusually positive CoII/CoI redox couples, and are also active proton reduction electrocatalysts.
A Compound of formula (I)
or tautomers, or stereoisomers, or solvates, or pharmaceutically acceptable salts thereof, wherein M
1
, M
1
, L
1
, L
2
, W
1
, W
2
, X
1
, X
2
, Y
1
, Y
2
, A, R
5
, and R
5a
are as defined herein for the treatment of conditions mediated by the blockade of an epithelial sodium channel, particularly an inflammatory or allergic condition.
Synthetic Approaches to Polypyridyl Bridging Ligands with Proximal Multidentate Binding Sites
作者:Ruifa Zong、Dong Wang、Richard Hammitt、Randolph P. Thummel
DOI:10.1021/jo051937r
日期:2006.1.1
A series of 12 bridging ligands was prepared. These ligands include a central linker appended to two 1,8-naphthyrid-2-yl or two 1,10-phenanthrolin-2-yl units. The linkers include pyridazin-3.6-diyl, 1,8-naphthyrid-2,7-diyl, 2,2'-bipyrid-6,6'-diyl, 1, 10-phenanthrolin-2,9-diyl, 1,2-di(2'-pyrid-6'-yl)ethyne, and 3,6-di(2'-pyrid-6'-yl)pyridazine. The ligands were synthesized from the diacetyl derivative of the central linker by a Friedlander condensation with either 2-aminonicotinaldehyde or 8-amino-7-quinolinecarbaldehyde. The precursor diacetyl derivatives were, in turn, prepared by pathways involving Stille and Sonogashira couplings. Examination of the electronic absorption spectra of the bridging ligands shows the strongest correlation to be between pairs of ligands having the same central linker. Complexation studies will follow.