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Novel low dielectric constant (low-k) polycarbosilanes with tunable performance are reported in the present work. These well-defined linear-cyclopolycarbosilanes were prepared via the copolymerization of 1,5-hexadiene (1,5-HD) with 3,3-dimethyl-3-sila-1,5-hexadiene (DMSHD) using dimethyl(pyridylamido) hafnium/[Ph3C][B(C6F5)4]/AliBu3 catalytic system. They exhibited excellent dielectric properties...
Activated by [Ph3C][B(C6F5)4], dimethylpyridylamidohafnium complex exhibited high performance in the copolymerization of propylene with 3,3-dimethyl-3-sila-1,5-hexadiene (DMSHD), producing high molecular weight random copolymers without pendent vinyl groups and cross-linking. The effects of the comonomer incorporation on chain microstructure, crystallinity, thermal properties and final mechanical...
A highly refractive and transparent poly(arylene sulfide sulfone) (PASS) containing pyrimidine (or pyridazine) unit has been developed. The polymer was prepared by a polycondensation reaction of 4,4′-dimercaptodiphenyl sulfone (DMDPS) and 4,6-dichloropyrimidine (DCPM) (or 3,6-dichloropyridazine (DCPD)). They showed good thermal stabilities such as a relatively high glass transition temperature of...
The series of ligands 2-(1-(arylimino)methyl)-8-(1H-benzimidazol-2-yl)quinolines was synthesized and used to prepare new iron(II) and cobalt(II) dichloride complexes. X-ray diffraction studies revealed that the coordination geometry around the metal center can best be described as distorted square-based pyramidal. Upon activation with methylaluminoxane (MAO), both families (Fe and Co) of complexes...
In the presence of [Ph 3 C][B(C 6 F 5 ) 4 ] and Triisobutylaluminium, dimethyl pyridylamidohafnium complex exhibited remarkable catalytic activity in the copolymerization of propylene with 1,5-hexadiene, affording high molecular weight copolymers with unimodal molecular weight distributions. More noticeably, the resultant copolymers contain absolutely cyclo-group in...
Several non-metallocene-type titanium(IV) complexes containing phenoxy-phosphine or thiophenoxy-phosphine ligands of type, (2-R 1 -4-R 2 -6-PPh 2 -C 6 H 2 X) 2 TiCl 2 (2a: X = O, R 1 = R 2 = t-Bu; 2b: X = O, R 1 = R 2 = cumyl; 2c: X = S, R 1 = SiMe 3 , R 2 = H) have been synthesized...
Novel terpolymers containing ethylene, 1-hexene and dicyclopentadiene (DCPD) were synthesized using bis(β-enaminoketonato)titanium catalysts [PhNC(R 2 )CHC(R 1 )O] 2 TiCl 2 (1a: R 1 = Ph, R 2 = CF 3 ; 1b: R 1 = CF 3 , R 2 = CH 3 ). In the presence of modified methylaluminoxane, these catalysts afforded terpolymers...
A facile self-condensing vinyl polymerization (SCVP) system, the combination of glycidyl methacrylate, Cp 2 TiCl 2 and Zn, has been firstly used to prepare novel hyperbranched polymers, consisting of vinyl polymers as the backbone, and cyclic ester polymers (poly(ɛ-caprolactone) or poly(l-lactide)) as the side chains. The polymerizations are initiated by the epoxide radical ring-opening...
A series of novel half-metallocene-type titanium complexes CpTiCl 2 [PhNC(R 2 )CHC(R 1 )O] (2a, R 1 = Cy, R 2 = CF 3 ; 2b, R 1 = t Bu, R 2 = CF 3 ; 2c, R 1 = Ph, R 2 = CF 3 ; 2d, R 1 = Ph, R 2 = CH 3 ) have been synthesized by treating CpTiCl 3 with the corresponding...
Hyperbranched polymers were produced using glycidyl methacrylate (GMA)/Cp2TiCl2/Zn as self-condensing vinyl polymerization (SCVP) system. The polymerization is firstly initiated by the epoxide radical ring opening catalyzed by Cp2Ti(III)Cl generated in situ via the reaction of Cp2TiCl2 with Zn. By optimizing the molar ratio of the SCVP inimer (GMA) to the mediator (Cp2Ti(III)Cl), the active propagation...
The copolymerizations of ethylene with polar hydroxyl monomers such as 10-undecen-1-ol, 5-hexen-1-ol and 3-buten-1-ol were investigated by the vanadium(III) catalysts bearing bidentate [N,O] ligands (1, [PhNC(CH 3 )CHC(Ph)O]VCl 2 (THF) 2 ; 2, [PhNCHC 6 H 4 O]VCl 2 (THF) 2 ; 3, [PhNCHC(Ph)CHO]VCl 2 (THF) 2 ). The polar monomers...
The 3D structure of the AmiF formamidase of Helicobacter pylori (denoted as AmiF(fhp)) is built by homology modeling. The docking studies show that AmiF(fhp) has restricted substrate specificity, as it only hydrolyzes formamide. In order to reveal the reaction mechanism and the catalytic role for Cys166, Lys133 and Asp168 in AmiF(fhp), three quantum mechanics' models are constructed based on the 3D...
Dissipative particle dynamics (DPD) simulations are carried out to study the translocation of a single polymer chain through a pore under fluid field. The influences of the field strength E, the chain length N, the solvent quality α sp , and the pore size h on the translocation time are evaluated. The translocation time τ, which is defined as the time that the chain moves through the pore...
With the aid of the automated molecular docking, the inhibition effect of 20(S)-Protopanaxadiol (PPD) and Ginsenoside Rh2 for CYP2C9 and CYP3A4, respectively, were studied by InsightII/Affinity program and the docking complexes were analyzed by InsightII/Ludi program. The results indicate that PPD is a competitive inhibitor for CYP2C9 but a poor inhibitor for CYP3A4, Rh2 is a noncompetitive inhibitor...
In order to understand the mechanisms of substrate specificity and the interaction between bergaptol and bergaptol O-methyltransferase (BMT), a 3D model of BMT is generated based on the crystal structure of caffeic acid 3-O-methyltransferase (COMT EC 2.1.1.68, PDB code 1KYZ) by using the InsightII/Homology module. With the aid of the molecular mechanics and molecular dynamics methods, the final refined...
Full atomistic molecular dynamics simulations have been used to study the diffusion of alkane molecule in single wall carbon nanotube (SWCNT), with different alkane chain lengths and nanotube diameters. In this paper, we calculated the self-diffusion coefficient, mean-square gyration and bond-orientation order parameter of alkane molecule and the average intermolecular interaction energy per segment...
Reflective and/or conductive surface silvered polyimide films have been prepared by using random and block copolyimide derived from pyromellitic dianhydride (PMDA), 4,4′-oxydiphthalic anhydride (ODPA) and 4,4′-oxydianiline (4,4′-ODA) as matrix and (trifluoroacetylacetonato) silver(I) (AgTFA) freshly synthesized from silver acetate and trifluoroacetylacetone as silver precursor. Influence of copolyimide...
The influence of the solvent evaporation rate on the crystallization of the poly(vinylcyclohexane)-b-poly(ethylene)-b-poly(vinylcyclohexane) (PVCH–PE–PVCH) triblock copolymer with the high T g of PVCH segment in chloroform was investigated. The competition between the crystallization of PE block and the vitrification of PVCH in the triblock copolymer was controlled through changing the solvent...
Jasmonic acid (JA) is a plant volatile that acts as an important cellular regulator mediating diverse developmental processes and defense responses. Not only the attacked plant but also neighboring plants are affected, becoming more attractive to herbivore predators and less susceptible to invaders. The three-dimensional (3D) model of methyl jasmonate esterase (MJE), which is only responsible for...
The three-dimensional (3D) model of the 3-hydroxykynurenine transaminase (3-HKT) is constructed based on the crystal structure of the alanine-glyoxylate aminotransferase (EC 2.6.1.44, PDB code 1VJO) by using InsightII/Homology module. With the aid of the molecular mechanics and molecular dynamics methods, the last refined model is obtained and further assessed by Profile-3D and ProStat, which confirm...
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