Li Jia

Li Jia
University of Akron · Department of Polymer Science

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23
Publications
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Introduction
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Publications

Publications (23)
Patent
Full-text available
N-type conjugated compounds are disclosed which include at least one conjugated electron-acceptor unit The conjugated electron-acceptor unit includes a diborylene unit. The compounds find application in an electron acceptor layer of an electronic device.
Article
A new type of polymer highly resistant to nonspecific protein adsorption is reported. Poly(N-methyl-β-alanine) (PMeA) and poly(N-ethyl-β-alanine) (PEtA) synthesized via cobalt-catalyzed carbonylative polymerization of N-methylaziridine and N-ethylaziridine were end-functionalized with thiol groups and grafted onto Au surfaces. Protein adsorption wa...
Article
The titled diblock copolymers are synthesized via cobalt-catalyzed living carbonylative polymerization of N-alkylaziridines under moderate pressures followed by a deprotection step. The poly(beta-alanine) block is solubilized by the poly(beta-alanoid) block in chloroform and remains fully hydrogen-bonded in the form of a sheet-like assembly.
Article
We provide a full account on our study of the cobalt-catalyzed carbonylative polymerization of N-alkylazetidines involving three representative monomers. The individual N-alkylazetidine monomers display different characteristics in the polymerization, allowing the incorporation of amine and ester units into the amide-based polymers. We will first p...
Article
Lebende Polymerisation: Poly(amid-co-ester) mit entweder ansteigender oder segmentärer Esterverteilung entstehen bei der Cobalt-katalysierten Polymerisation von Azetidin in THF in Abwesenheit bzw. Gegenwart von LiI. Die periodische Zugabe von Azetidin führt zu Copolymeren aus alternierenden Amid- und Estersegmenten (siehe Bild). Die Polymere unterl...
Article
A series of CH3COCo(CO)3L complexes (1, L=PCy3; 2, L=PMe2Ph; 3, L=PPh3; 4, L=P(para-F-Ph)3; 5, L=P(meta-F-Ph)3; and 6, L=P(ortho-tolyl)3) were studied as precatalyst for the title polymerization. The Co–P bond length primarily responds to the cone angle of the phosphine ligand (6>1>2≈3≈4≈5), while the back-donation to the axial acetyl ligand and th...
Article
The combination of CH3C(O)Co(CO)3P(o-tolyl)3/m-methoxypyridine serves as a versatile catalyst for both the carbonylative polymerizations of epoxides and N-alkylaziridines under closely resembling mechanistic hypotheses. Diblock poly(beta-alanoid-b-beta-hydroxypropionate)s can be synthesized even when the aziridine and epoxide comonomers are added a...
Article
The stereospecificity of the title reaction is studied using the (4R,5S)-4-methyl-2,5-diphenyl-2-oxazoline and (4R,5R)-4-methyl-2,5-diphenyl-2-oxazoline as the substrates. While the catalyst system containing BnCo(CO)4 and BnCOCo(CO)4 (1) was used initially, a convenient catalyst formulation generated from the commercially available Co2(CO)8 and AI...
Article
[reaction: see text] Initial studies of a rare exocyclic C-O bond carbonylation are reported. Under the catalysis of Co(2)(CO)(8) in the absence of HI as the copromoter, cycloimino esters are carbonylated to afford N-acyllactams in high yields under relatively mild conditions (100-160 degrees C and 200-1000 psi). The reaction is interesting because...
Article
Catalytic ring-expanding carbonylation of 2-aryl-2-oxazolines is reported as a novel method for the synthesis of 4,5-dihydro-1,3-oxazin-6-ones. Various observations suggest the involvement of cobalt radicals as the catalytically active species. [reaction: see text]
Article
Catalysts CH3COCo(CO)3PPh3 (1) and HCo(CO)3PPh3 (2) catalyze the copolymerization of aziridine and carbon monoxide. Catalyst 2 can be conveniently generated insitu via reaction of Na+Co(CO)4, N,N-dimethylanilinium chloride, and PPh3. The copolymerization alternates at high catalyst loadings to produce poly(β-alanine). The end groups of the poly(β-a...
Article
The title copolymerization catalyzed by BnCOCo(CO)4 affords poly-beta-alanoids in excellent yields and selectivity. The poly-beta-alanoids have narrow molecular weight distributions, controllable molecular weights, and definite end groups.
Article
Aminolysis of Zr(CH2C6H5)4 with CH[(CH3)2SiNHAr]3 (Ar = para-tolyl and para-fluorophenyl) affords CH[(CH3)2SiNAr]3ZrCH2C6H51a and 1b (a: Ar = para-tolyl; b: Ar = para-fluorophenyl). Solution and solid state X-ray structural data suggest an η2-bonding mode for the benzyl group in 1a and 1b. Treating 1a and 1b with N,N-dimethylanilinium chloride or t...
Article
Alternating copolymerization of carbon monoxide with aziridine was realized, which serves as a prototype of a novel route for synthesis of poly-β-peptides.
Article
Synthesis, structural characterization, and preliminary reactivity studies of the title compounds are reported. The ethylene polymerization and diene cyclization activities that these complexes have shown are unprecedented for neutral molecules of the type X3MR (X = amide, alkoxide, or siloxide; M = group 4 metal; R = alkyl or hydride).
Article
The synthesis and properties of two soluble, weakly coordinating derivatives of the tetrakis(perfluoroaryl)borate anion B(4-C6F4TBS)4- and B(4-C6F4TIPS)4- (TBS = tert-butyldimethylsilyl and TIPS = triisopropylsilyl) are reported. Reaction of the trityl salts of the above anions with a variety of zirconium and thorium L2MMe2 complexes in benzene or...
Article
A series of zirconium and lanthanide metallocene catalysts are active in the regioselective ring-opening polymerization of strained exo-methylenecycloalkanes to yield exo-methylene-functionalized polyethylenes. MCB (methylenecyclobutane) affords the polymer [CH2CH2CH2C(CH2)]n under the catalytic action of (1,2-Me2Cp)2ZrMe+MeB(C6F5)3-, and MCP (meth...
Article
We wish to communicate here the delineation of a sequential metallocenium-catalyzed ring-opening - `zipping-up` Ziegler polymerization of methylenecyclopropane which yields, in high chemo- and stereoselectivity, a saturated polyspirane having structure B, poly(1,4:2,2-butanetetrayl), as well as some of the interesting structural and thermal propert...
Article
A polymer having a repeating unit of ##STR1## and a method for preparing it through Zr-catalyzed polymerization of methylenecyclopropane is disclosed.
Article
The functionalized (fluoroaryl)borate salts Ph{sub 3}C{sup +}B(C{sub 6}F{sub 4}TBS){sub 4}{sup -} and Ph{sub 3}C{sup +}B(C{sub 6}F{sub 4}TBS){sub 4}{sup -} and (TBS - {sup t}BuMe{sub 2}Si; TIPS = {sup i}Pr{sub 3}Si) are prepared in three steps from 1,4-HC{sub 6}F{sub 4}Br. Reaction with zirconocene dimethyls yields crystalline, thermally stable, so...
Article
Reaction of (t)BuCH2CH(BCl2)2 with LiC6F5 yields the binuclear organo-Lewis acid (t)BuCH2CH-[B(C6F5)2]2, which can be converted with KEt3BH, followed by metathesis, into the salt [HN(n)Bu3]+{(t)BuCH2-CH[B(C6F5)2]2H}-. Reaction of this salt with Cp'2Th-(CH3)2 (Cp' = eta5-Me5C5) yields the cationic metallocene complex Cp'2ThCH3+{(t)BuCH2CH[B(C6F5)2]2...

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Project (1)
Project
A tailor-made rubber material that could survive on Mars Lightweight materials that exhibit a high strength-to-weight ratio and are aging resistant could withstand the harsh conditions on Mars. Funded by the Marie Skłodowska-Curie Actions programme, the RED 4 MARS project plans to design a rubber material with improved properties that can endure the high dose of cosmic radiation and the low temperatures on the Martian surface. This tailor-made rubber will have a low glass transition temperature, contain functional and self-healing groups and reinforcing fillers that should confer the material with excellent mechanical properties and aging resistance.