1945-78-4Relevant articles and documents
Structure-property-relationship studies with ethylene polymerization catalysts of Ti, Zr and V containing heterocyclic ligands
Elagab, Hamdi Ali,Alt, Helmut G.
, p. 26 - 35 (2015)
21 complexes of bis(benzimidazolyl, benzothiazolyl and benzoxazolyl)methane compounds with Zr(IV), Ti(IV), V(III) metal centers were synthesized, characterized, activated with methylalumoxane (MAO) and then tested for catalytic ethylene polymerization. The activities of the various catalysts were found to be functions of the hetero atoms in the ligand frameworks. The methylene moiety as bridging unit of the two heterocyclic ring systems gave higher catalyst activities than the corresponding 1,2-ethylidene derivatives indicating a strong influence of the bridging unit of the ligand on the catalyst activity. The activity of the catalyst system 10/MAO was investigated with different cocatalyst concentrations. The highest activity was obtained with 23/MAO (573 kg PE/mol cat h). The produced polyethylenes showed high molecular weights (up to 1.77·106 g/mol) and broad molecular weight distributions (up to PD = 64.5). This could result from different interactions of the MAO counterion with the heteroatoms of the catalyst ligand generating different active sites. These catalysts open an easy access to single-reactor multimodal polyethylene technology.
Head-to-head bisbenzazole derivatives as antiproliferative agents: design, synthesis, in vitro activity, and SAR analysis
Ersan, Ronak Haj,Alagoz, Mehmet Abdullah,Ertan-Bolelli, Tugba,Duran, Nizami,Burmaoglu, Serdar,Algul, Oztekin
, p. 2247 - 2259 (2020/06/27)
Abstract: In the present work, a series of bisbenzazole derivatives were designed and synthesized as antiproliferative agents. The antiproliferative activity of these compounds was investigated using MTT assay. Bisbenzazole derivatives showed significant antiproliferative activity against all the four tested cancer cell lines. Among the various bisbenzazole derivatives, bisbenzoxazole derivatives exhibited the most promising anticancer activity followed by bisbenzimidazole and bisbenzothiazole derivatives. All the derivatives were found to be less toxic as compared to methotrexate (positive control) in normal human cells, indicating selective and efficient antiproliferative activity of these bisbenzazole derivatives. The structure–activity relationships of heteroaromatic systems and linkers present in bisbenzazole derivatives were analyzed in detail. In silico ADMET prediction revealed that bisbenzazole is a drug-like small molecule with a favorable safety profile. Compound 31 is a potential antiproliferative hit compound that exhibits unique cytotoxic activity distinct from methotrexate. Graphic abstract: Twenty-one bisbenzoxazole derivatives have been designed synthesized and evaluated to be an antiproliferative activity against four human tumor cell lines.[Figure not available: see fulltext.]
Zr(IV) complexes of some heterocyclic ligands: Synthesis, characterization, and ethylene polymerization activity
Elagab, Hamdi Ali
, p. 742 - 761 (2016/11/09)
Thirty-one complexes of bis-(benzimidazole, benzothiazole, and benzoxazole) compounds with Zr(IV) metal centers were synthesized, characterized, activated with methylaluminoxane (MAO), and then tested for catalytic ethylene polymerization. The activities of the various catalysts were found to be functions of the heteroatoms in the ligand frameworks and the structure around the active metal center. The highest activity was obtained with 38/MAO (424 kg E/mol cat. h). The produced polyethylenes showed high molecular weights (41/MAO, 1.9 × 106 g/mol) and broad molecular weight distributions (38/MAO, Mw = 9.64 × 105 g/mol, PD = 23). This could result from different interactions of the MAO counter ion with the heteroatoms of the catalyst ligand generating different active sites.
