Synthesis of a norbornene monomer having cyclic carbonate moiety based on CO2 fixation and its transition metal‐catalyzed polymerizations

A norbornene monomer bearing cyclic carbonate moiety ( NB‐CC ) was successfully synthesized from the corresponding precursor having epoxy moiety by its reaction with carbon dioxide under atmospheric pressure, which was efficiently catalyzed by lithium bromide. NB‐CC underwent the ring‐opening metathesis polymerization (ROMP) catalyzed by a ruthenium carbene complex to give the corresponding poly(norbornene), of which side chain inherited the cyclic carbonate moiety from the monomer without any deterioration. The same ROMP system was applicable to the copolymerization of NB‐CC and 5‐butyl‐2‐norbornene ( BNB ), which afforded the corresponding copolymer with a composition ratio same as a feed ratio. In addition, by using a catalytic system consisted of palladium (II) acetate/tricyclohexylphosphine/triphenylcarbenium tetrakis(pentafluorophenyl)borate, the copolymerization of NB‐CC and BNC proceeded successfully in a vinyl addition polymerization mode to give the corresponding poly(norbornene) having CC moiety in the side chain. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3896–3902, 2010     

Novel palladium acetate based protocols for transformations of unsaturated hydrocarbons

Catalyst systems based on palaadium carboxylates and boron trifluoride etherate were examined in the dimerization of styrene, telomerization of butadiene with diethylamine and homopolymerization of norbornene. The systems are shown to have higher efficiency than their palladium β-diketonate prototypes at analogous conditions.     

Vinyl polymerization of norbornene catalyzed by 2‐Py‐amidine Ni(II) complex/methylaluminoxane systems

Two 2‐Py‐amidine ligands (2‐Py―NH―C(Ph)═N―Ar, Ar = 2,6‐Me₂C₆H₃ and 2,6‐ⁱPr₂C₆H₃) and the corresponding Ni(II) complexes ( 1 and 2 ) were synthesized and characterized using elemental analysis and FT‐IR, UV–visible, ¹H NMR and ¹³C NMR spectroscopies. X‐ray crystal structures indicate that the chelate ring conformation of the less bulky complex 1 is relatively planar compared with that of the bulky complex 2 . Paramagnetic ¹H NMR and ¹³C NMR studies show that, in solution, the time‐average structures of complexes 1 and 2 have mirror symmetry. Both complexes 1 and 2 were used as catalyst precursors for norbornene polymerization with methylaluminoxane as a co‐catalyst. The effects of Al/Ni ratio, temperature and structure of precursors on the catalytic performance were investigated. Copyright © 2014 John Wiley & Sons, Ltd.     

巯基硅溶胶对改性亚麻籽油紫外光固化反应活性的影响

用溶胶-凝胶法制备了新型的多功能巯基硅氧烷溶胶;用亚麻籽油和环戊二烯合成了可光聚合的改性亚麻籽油低聚物(NLO),并用红外光谱(FT-IR)表征了其结构。用光-差示扫描热分析(Photo-DSC)和在线红外(RT-IR)对NLO、巯基硅氧烷的紫外光固化体系的光聚合反应活性及可光聚合官能团的转化率进行了动力学研究。结果表明:巯基硅氧烷能大大提高NLO的自由基聚合速率,环烯键对硫醇十分敏感,巯基硅氧烷溶胶兼具光引发剂和交联剂的作用。     

Structural elucidation of dioxa‐cage compounds from tetrahydroisobenzofuran‐1(3H)‐one: analysis of NMR data and GIAO chemical shifts calculations

The polycyclic compounds, especially the dioxa‐cages, have attracted considerable attention in recent years. In our work, a series of 9β‐substituted 3‐oxo‐4,11‐dioxatetracyclo[5.2.1.1^5,8.0^2,6]undecane compounds were unexpectedly isolated during bromination, chlorination and epoxidation reactions of the 3‐hydroxy‐3a,4,7,7a‐tetrahydro‐4,7‐methanoisobenzofuran‐1(3H)‐one. After careful analysis of the NMR data, the chemical shifts of the isolated and the expected products were predicted by theoretical calculations using density functional theory and gauge including atomic orbitals. The best correlation between calculated and experimental data was evaluated by comparing mean absolute errors and applying DP4 probability methodology. Results from both approaches indicated a correct structural elucidation. Copyright © 2016 John Wiley & Sons, Ltd.     

Composition distribution of ethylene or propylene–norbornene copolymers obtained with zirconocene catalysts

Copolymerization of ethylene or propylene and norbornene (NB) was carried out with stereospecific zirconocene catalysts rac‐ethylenebis(indenyl)zirconium dichloride, rac‐dimethylsilylenebis(indenyl)zirconium dichloride ( 2 ), rac‐dimethylsilylenebis(2‐methylindenyl)zirconium dichloride, and diphenylmethylene(cyclopentadienyl)(9‐fluorenyl)zirconium dichloride combined with cocatalysts at 40 °C. Temperature‐rising elution fractionation of the copolymers was carried out with cross‐fractionation chromatography with o‐dichlorobenzene as a solvent, and a broad distribution of the copolymer composition was detected. The fraction eluted at lower temperature contained higher NB. The effect of the polymerization time was examined in the ethylene–NB copolymerization with catalyst 2 , and the higher‐temperature elution fraction increased with increasing polymerization time. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 441–448, 2003     

Water‐soluble polymers from acid‐functionalized norbornenes

Unprotected exo,exo‐5‐norbornene‐2,3‐dicarboxylic acid and exo,exo‐7‐oxa‐5‐norbornene‐2,3‐dicarboxylic acid were polymerized via ring‐opening metathesis polymerization. This reaction yielded polymers with molecular weights (M_n from GPC) ranging from 31 to 242 kg/mol and polydispersity indices between 1.05 and 1.12, using Grubbs' third generation catalyst. The water solubility as a function of pH value of the polymers was investigated by dynamic light scattering (DLS). DLS and acid‐base titration revealed that the oxanorbornene polymer was water soluble over a wider pH range than its norbornene analog. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1266–1273, 2009     

Vinylic and ring‐opening metathesis polymerization of norbornene with bis(β‐ketoamine) cobalt complexes

Cobalt complexes 1 – 4 bearing N,O‐chelate ligands based on condensation products of 1‐phenyl‐3‐methyl‐4‐benzoyl‐5‐pyrazolone with aniline, o‐methylaniline, α‐naphthylamine, and p‐nitroaniline, respectively, were synthesized, and the structures of 1 and 4 were characterized by single‐crystal X‐ray diffraction analyses. The bis(β‐ketoamine) cobalt complexes could act as moderately active catalyst precursors for norbornene polymerization with the activation of methylaluminoxane. This catalytic reaction proceeded mainly through a vinyl‐type polymerization mechanism. ¹H NMR and IR showed that in all cases, a small amount of double bonds raised from ring‐opening metathesis polymerization (ROMP) was present in the polymerization products. The variation of the polymerization conditions affected the ROMP unit ratio in the polynorbornenes. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5535–5544, 2005