24010-73-9Relevant academic research and scientific papers
Synthesis and characterization of titanium complexes bearing sulfoxide groups and their catalytic behaviors in ethylene homo- and copolymerization
Wang, Zheng,Peng, Ai-Qing,Sun, Xiu-Li,Tang, Yong
, p. 1144 - 1149 (2014)
Titanium complexes derived from 2,4-di-tert-butyl-6-((2-(arylsulfinyl) phenylimino)methyl)phenol are designed and synthesized. X-ray diffraction studies reveal that the complexes adopt distorted octahedral geometry with O(phenol), N(imine), and O(sulfoxide) coordinated with titanium. Combined with modified methylaluminoxane(MMAO), the complexes exhibit moderate to high activity to afford polyethylene even at 120 °C under 1 atm ethylene pressure. The complexes also show excellent capability in copolymerization of ethylene with either 1-hexene or norbornene. Results indicate that the introduction of sulfoxide groups could open the space around central metal and favors the insertion of bulky comonomers.
Role of steric hindrance in the Newman-Kwart rearrangement and in the synthesis and photophysical properties of arylsulfanyl tetrapyrazinoporphyrazines
Novakova, Veronika,Miletin, Miroslav,Filandrova, Tereza,Lenco, Juraj,Ruiszicka, Ales,Zimcik, Petr
, p. 2082 - 2093 (2014/04/03)
Conditions for the Newman-Kwart rearrangement of phenols into thiophenols were investigated in relation to the bulkiness of substituents at the 2 and 6 positions of the starting phenol derivative with an emphasis on eliminating side reactions. Thiophenols with different 2,6-disubstitution patterns (including hydrogen, methyl, isopropyl or tert-butyl groups) were used for the synthesis of 5,6-bis(arylsulfanyl)pyrazine-2,3-dicarbonitriles that underwent cyclotetramerization leading to the corresponding zinc tetrapyrazinoporphyrazines (TPyzPz), aza-analogues of phthalocyanines. Several methods for the cyclotetramerization were attempted to eliminate problematic side reactions. Magnesium butoxide was found as the most suitable cyclotetramerization agent and afforded TPyzPzs in reasonable yields of approximately 30% under mild conditions. The varying arrangements of the peripheral substitutions resulting from the different bulkiness of the substituents were demonstrated by the X-ray structures of the pyrazine-2,3-dicarbonitriles. The prepared zinc arylsulfanyl TPyzPzs showed an absorption maximum at a Q-band over 650 nm, fluorescence quantum yields between 0.078 and 0.20, and singlet oxygen quantum yields ranging 0.58-0.69. TPyzPzs with isopropyl groups were found to be the best derivatives in this series as they combined facile cyclotetramerization, no aggregation, and good photophysical properties, which makes them potentially suitable for photodynamic therapy.
A high temperature investigation using microwave synthesis for electronically and sterically disfavoured substrates of the Newman-Kwart rearrangement
Moseley, Jonathan D.,Lenden, Philip
, p. 4120 - 4125 (2008/01/03)
Electronically deactivated and/or sterically hindered substrates undergo the Newman-Kwart rearrangement (NKR) at around 300 °C, beyond the range of most convenient and safe, small-scale laboratory equipment. We report here the convenient conversions of several difficult substrates using modern microwave technology, which has proven ideal for investigating this high temperature reaction in all but the?most refractory of cases. In addition, several previously reported difficult examples were re-investigated, and found not to require high temperatures under these conditions, for various reasons which are elaborated upon.
Rhenium Nitrosyl Complexes with Simple and with Sterically Demanding Aromatic Thiolate Ligands: X-Ray Crystal Structures of *CH2Cl2 and i2-2,6)4(NO)>
Blower, Philip J.,Dilworth, Jonathan R.,Hutchinson, John P.,Zubieta, Jon A.
, p. 1533 - 1542 (2007/10/02)
Reaction of with a range of thiophenols under basic conditions gives one of two classes of products depending on the steric requirements of the thiols.A representative member of each class has been characterised by an X-ray crystal
