scholarly journals Suzuki–Miyaura Catalyst-Transfer Polycondensation of Triolborate-Type Carbazole Monomers

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4168
Author(s):  
Saburo Kobayashi ◽  
Mayoh Ashiya ◽  
Takuya Yamamoto ◽  
Kenji Tajima ◽  
Yasunori Yamamoto ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Diblock Copolymers ◽  
Side Reaction ◽  
Product Formation ◽  
Chain Growth ◽  
Block Copolymerization ◽  
Synthetic Strategy ◽  
Polymerization System ◽  
A Chain ◽  
First Time

Herein, we report the Suzuki–Miyaura catalyst-transfer polycondensation (SCTP) of triolborate-type carbazole monomers, i.e., potassium 3-(6-bromo-9-(2-octyldodecyl)-9H-carbazole-2-yl)triolborate (M1) and potassium 2-(7-bromo-9-(2-octyldodecyl)-9H-carbazole-2-yl) triolborate (M2), as an efficient and versatile approach for precisely synthesizing poly[9-(2-octyldodecyl)-3,6-carbazole] (3,6-PCz) and poly[9-(2-octyldodecyl)-2,7-carbazole] (2,7-PCz), respectively. The SCTP of triolborate-type carbazole monomers was performed in a mixture of THF/H2O using an initiating system consisted of 4-iodobenzyl alcohol, Pd2(dba)3•CHCl3, and t-Bu3P. In the SCTP of M1, cyclic by-product formation was confirmed, as reported for the corresponding pinacolboronate-type monomer. By optimizing the reaction temperature and reaction time, we successfully synthesized linear end-functionalized 3,6-PCz for the first time. The SCTP of M2 proceeded with almost no side reaction, yielding 2,7-PCz with a functional initiator residue at the α-chain end. Kinetic and block copolymerization experiments demonstrated that the SCTP of M2 proceeded in a chain-growth and controlled/living polymerization manner. This is a novel study on the synthesis of 2,7-PCz via SCTP. By taking advantage of the well-controlled nature of this polymerization system, we demonstrated the synthesis of high-molecular-weight 2,7-PCzs (Mn = 5–38 kg mol−1) with a relatively narrow ÐM (1.35–1.48). Furthermore, we successfully synthesized fluorene/carbazole copolymers as well as 2,7-PCz-containing diblock copolymers, demonstrating the versatility of the present polymerization system as a novel synthetic strategy for well-defined polycarbazole-based materials.

Catalyst-Transfer Condensation Polymerization for the Synthesis of Well-Defined Polythiophene with Hydrophilic Side Chain and of Diblock Copolythiophene with Hydrophilic and Hydrophobic Side Chains

2007 ◽  
Vol 19 (5-6) ◽  
pp. 684-699 ◽  
Author(s):  
Tsutomu Yokozawa ◽  
Isao Adachi ◽  
Ryo Miyakoshi ◽  
Akihiro Yokoyama
Keyword(s):  
Block Copolymer ◽  
Feed Ratio ◽  
Ni Catalyst ◽  
Chain Growth ◽  
Condensation Polymerization ◽  
Block Copolymerization ◽  
Ni Catalysts ◽  
Linear Relationships ◽  
A Chain ◽  
Polymerization Method

Chain-growth condensation polymerization of 2-bromo-5-chloromagnesio-3-[2-(2-metho-xyethoxy)ethoxy]methylthiophene (2) with Ni catalysts was studied, and the block copolymer of poly2 and poly(3-hexylthiophene) was synthesized by this polymerization method. The polymerization of 2 depended on the ligands of the Ni catalyst, and poly2 with the lowest polydispersity was obtained when 1,2-bis(diphenylphosphino)ethane (dppe) was used as the ligand. The linear relationships between the conversion of 2 and Mn of the polymer and between the feed ratio of 2 to the Ni catalyst and Mn of the polymer indicate that this polymerization proceeds in a chain-growth polymerization manner via a catalyst-transfer condensation polymerization mechanism. The block copolymerization of 2 and 2-bromo-5-chloromagnesio-3-hexylthiophene (1) was then carried out in four ways by changing the order of polymerization of the two monomers and the catalysts. It turned out that the block copolymer was obtained without the formation of the homopolymers by the polymerization of 1 with Ni(dppe)Cl2 or Ni(dppp)Cl2 (dppp = 1,2-bis(diphenylphosphino)propane), followed by the postpolymerization of 2. Of the two catalysts, Ni(dppe)Cl2 resulted in narrower polydispersity of the block copolymer.

First GPC results of terpyridine based chain extended supramolecular polymers: comparison with viscosity and analytical ultracentrifugation

e-Polymers ◽  
2006 ◽  
Vol 6 (1) ◽  
Author(s):  
Michael A. R. Meier ◽  
Harald Hofmeier ◽  
Caroline H. Abeln ◽  
Christos Tziatzios ◽  
Mircea Rasa ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Analytical Ultracentrifugation ◽  
Average Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Supramolecular Polymers ◽  
Supramolecular Polymer ◽  
Poly Ethylene ◽  
A Chain ◽  
First Time ◽  
Good Agreement

AbstractThe molecular weight of an extended metallo-supramolecular polymer, based on a α,ω-bis-terpyridine-poly(ethylene glycol) polymer linked via ruthenium(II) ions, was determined by gel permeation chromatography, viscosimetry as well as analytical ultracentrifugation. An optimized GPC method was applied for the first time to this kind of chain extended supramolecular polymers and the obtained results showed a good agreement with viscosimetry and analytical ultracentrifugation. A chain extended polymer with an average molecular weight of around 140 000 was found. These results clearly demonstrate that well-soluble high-molecular-weight metal-containing coordination polymers that are based on well-defined telechelics can be synthesized and fully characterized.

scholarly journals Transition-metal-free controlled polymerization for poly(p-aryleneethynylene)s

2015 ◽  
Vol 6 (1) ◽  
pp. 492-496 ◽  
Author(s):  
Takanobu Sanji ◽  
Asahi Motoshige ◽  
Hideaki Komiyama ◽  
Junko Kakinuma ◽  
Rie Ushikubo ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Transition Metal ◽  
High Molecular Weight ◽  
Catalytic Amount ◽  
Chain Growth ◽  
Controlled Polymerization ◽  
High Molecular Weight Polymer ◽  
Molecular Weight Polymer ◽  
Metal Free ◽  
A Chain

A catalytic amount of fluoride anions promoted the polymerization of 1-pentafluorophenyl-4-[(trimethylsilyl)ethynyl]benzene, providing a high-molecular-weight polymer in a chain-growth-like manner.

One-pot synthesis of grafted brush copolymers via a chain-growth radical/oxidative dual polymerization system

RSC Advances ◽  
2015 ◽  
Vol 5 (114) ◽  
pp. 93717-93723 ◽  
Author(s):  
Patakamuri Govindaiah ◽  
Yong Seok Kim ◽  
Jae Keun Hong ◽  
Jung Hyun Kim ◽  
In Woo Cheong
Keyword(s):  
Chain Growth ◽  
One Pot ◽  
One Pot Synthesis ◽  
System P ◽  
Polymerization System ◽  
One Step ◽  
A Chain ◽  
Metal Catalyzed

Grafted brush copolymers via one-step metal-catalyzed chain-growth radical/oxidative dual polymerization.

scholarly journals Specific Seminal Plasma Fractions Are Responsible for the Modulation of Sperm–PMN Binding in the Donkey

Animals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1388
Author(s):  
Jordi Miró ◽  
Jaime Catalán ◽  
Henar Marín ◽  
Iván Yánez-Ortiz ◽  
Marc Yeste
Keyword(s):  
Molecular Weight ◽  
Sperm Motility ◽  
Seminal Plasma ◽  
Potential Effect ◽  
Polymorphonuclear Neutrophils ◽  
Low Fertility ◽  
Plasma Fractions ◽  
Complex Fluid ◽  
First Time

While artificial insemination (AI) with frozen-thawed sperm results in low fertility rates in donkeys, the addition of seminal plasma, removed during cryopreservation, partially counteracts that reduction. Related to this, an apparent inflammatory reaction in jennies is induced following AI with frozen-thawed sperm, as a high amount of polymorphonuclear neutrophils (PMN) are observed within the donkey uterus six hours after AI. While PMN appear to select the sperm that ultimately reach the oviduct, two mechanisms, phagocytosis and NETosis, have been purported to be involved in that clearance. Remarkably, sperm interacts with PMN, but the presence of seminal plasma reduces that binding. As seminal plasma is a complex fluid made up of different molecules, including proteins, this study aimed to evaluate how different seminal plasma fractions, separated by molecular weight (<3, 3–10, 10–30, 30–50, 50–100, and >100 kDa), affect sperm–PMN binding. Sperm motility, viability, and sperm–PMN binding were evaluated after 0 h, 1 h, 2 h, 3 h, and 4 h of co-incubation at 38 °C. Two seminal plasma fractions, including 30–50 kDa or 50–100 kDa proteins, showed the highest sperm motility and viability. As viability of sperm not bound to PMN after 3 h of incubation was the highest in the presence of 30–50 and 50–100 kDa proteins, we suggest that both fractions are involved in the control of the jenny’s post-breeding inflammatory response. In conclusion, this study has shown for the first time that specific fractions rather than the entire seminal plasma modulate sperm–PMN binding within the donkey uterus. As several proteins suggested to be involved in the control of post-AI endometritis have a molecular weight between 30 and 100 kDa, further studies aimed at determining the identity of these molecules and evaluating their potential effect in vivo are much warranted.

scholarly journals Characterization of a Novel Fructosyltransferase from Lactobacillus reuteri That Synthesizes High-Molecular-Weight Inulin and Inulin Oligosaccharides

2002 ◽  
Vol 68 (9) ◽  
pp. 4390-4398 ◽  
Author(s):  
S. A. F. T. van Hijum ◽  
G. H. van Geel-Schutten ◽  
H. Rahaoui ◽  
M. J. E. C. van der Maarel ◽  
L. Dijkhuizen
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Lactobacillus Reuteri ◽  
Bacterial Strains ◽  
Potential Health ◽  
Isolation And Characterization ◽  
A Cell ◽  
Encoding Gene ◽  
First Time

ABSTRACT Fructosyltransferase (FTF) enzymes produce fructose polymers (fructans) from sucrose. Here, we report the isolation and characterization of an FTF-encoding gene from Lactobacillus reuteri strain 121. A C-terminally truncated version of the ftf gene was successfully expressed in Escherichia coli. When incubated with sucrose, the purified recombinant FTF enzyme produced large amounts of fructo-oligosaccharides (FOS) with β-(2→1)-linked fructosyl units, plus a high-molecular-weight fructan polymer (>107) with β-(2→1) linkages (an inulin). FOS, but not inulin, was found in supernatants of L. reuteri strain 121 cultures grown on medium containing sucrose. Bacterial inulin production has been reported for only Streptococcus mutans strains. FOS production has been reported for a few bacterial strains. This paper reports the first-time isolation and molecular characterization of (i) a Lactobacillus ftf gene, (ii) an inulosucrase associated with a generally regarded as safe bacterium, (iii) an FTF enzyme synthesizing both a high molecular weight inulin and FOS, and (iv) an FTF protein containing a cell wall-anchoring LPXTG motif. The biological relevance and potential health benefits of an inulosucrase associated with an L. reuteri strain remain to be established.

Monte Carlo simulation of folding transitions of simple model proteins using a chain growth algorithm

1992 ◽  
Vol 97 (11) ◽  
pp. 8644-8652 ◽  
Author(s):  
Eamonn M. O’Toole ◽  
Athanassios Z. Panagiotopoulos
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Simple Model ◽  
Chain Growth ◽  
A Chain
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