Synthesis and thermal decarbonylation of W(CO)5 complexes supported by nitrile, pyridine or phosphine ligands to poly-spirophosphazene random copolymers carrying O–C6H5–CO2Pr groups

Polyhedron ◽  
2006 ◽  
Vol 25 (1) ◽  
pp. 105-112 ◽  
Author(s):  
Gabino A. Carriedo ◽  
F.J. Garcia Alonso ◽  
Carlos Diaz Valenzuela ◽  
Maria Luisa Valenzuela
Keyword(s):  
Phosphine Ligands ◽  
Random Copolymers ◽  
Thermal Decarbonylation

Electron microscopy of crystalline structure in thermotropic random copolymers

1991 ◽  
Vol 49 ◽  
pp. 1054-1055
Author(s):  
Afzana Anwer ◽  
S. Eilidh Bedford ◽  
Richard J. Spontak ◽  
Alan H. Windle
Keyword(s):  
Electron Microscopy ◽  
Crystalline Structure ◽  
Liquid Crystalline ◽  
Elevated Temperatures ◽  
Random Copolymers ◽  
Molecular Characteristics ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Identical Monomer ◽  
Periodic Layer

Random copolyesters composed of wholly aromatic monomers such as p-oxybenzoate (B) and 2,6-oxynaphthoate (N) are known to exhibit liquid crystalline characteristics at elevated temperatures and over a broad composition range. Previous studies employing techniques such as X-ray diffractometry (XRD) and differential scanning calorimetry (DSC) have conclusively proven that these thermotropic copolymers can possess a significant crystalline fraction, depending on molecular characteristics and processing history, despite the fact that the copolymer chains possess random intramolecular sequencing. Consequently, the nature of the crystalline structure that develops when these materials are processed in their mesophases and subsequently annealed has recently received considerable attention. A model that has been consistent with all experimental observations involves the Non-Periodic Layer (NPL) crystallite, which occurs when identical monomer sequences enter into register between adjacent chains. The objective of this work is to employ electron microscopy to identify and characterize these crystallites.

Fluctuation Theory of Random Copolymers

1995 ◽  
Vol 5 (3) ◽  
pp. 365-377 ◽  
Author(s):  
Andrey V. Dobrynin ◽  
Igor Ya. Erukhimovich
Keyword(s):  
Fluctuation Theory ◽  
Random Copolymers

Fluctuation Theory of Charged AB-Random Copolymers

1995 ◽  
Vol 5 (8) ◽  
pp. 1241-1253 ◽  
Author(s):  
Andrey V. Dobrynin
Keyword(s):  
Fluctuation Theory ◽  
Random Copolymers

scholarly journals Crystallization of Random Metallocene-Catalyzed Propylene-Based Copolymers with Ethylene and 1-Hexene on Rapid Cooling

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2091
Author(s):  
Daniela Mileva ◽  
Jingbo Wang ◽  
René Androsch ◽  
Katalee Jariyavidyanont ◽  
Markus Gahleitner ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
Metallocene Catalyst ◽  
Nucleating Agent ◽  
Random Copolymers ◽  
Rapid Cooling ◽  
Significant Difference ◽  
Chip Calorimetry ◽  
High Cooling Rates ◽  
Fast Scanning Chip Calorimetry

Propylene-based random copolymers with either ethylene or 1-hexene as comonomer, produced using a metallocene catalyst, were studied regarding their crystallization behaviors, with a focus on rapid cooling. To get an impression of processing effects, fast scanning chip calorimetry (FSC) was used in addition to the characterization of the mechanical performance. When comparing the comonomer type and the relation to commercial grades based on Ziegler–Natta-type catalysts, both an interaction with the catalyst-related regio-defects and a significant difference between ethylene and 1-hexene was observed. A soluble-type nucleating agent was found to modify the behavior, but to an increasingly lesser degree at high cooling rates.

Ruthenium(II) Complexes with N-Heterocyclic Carbene-Phosphine Ligands for the N-Alkylation of Amines with Alcohols

2021 ◽  
Author(s):  
Ming Huang ◽  
Yinwu Li ◽  
Xiao-Bing Lan ◽  
Jiahao Liu ◽  
Cunyuan Zhao ◽  
...  
Keyword(s):  
Metal Hydride ◽  
Phosphine Ligands ◽  
Hydride Complexes ◽  
Borrowing Hydrogen ◽  
Hydrogen Autotransfer

Metal hydride complexes are key intermediates for N-alkylation of amines with alcohols by borrowing hydrogen/hydrogen autotransfer (BH/HA) strategy. Reactivity tuning of metal hydride complexes could adjust the dehydrogenation of alcohols...

scholarly journals Efficient photorelease of carbon monoxide from a luminescent tricarbonyl rhenium(i) complex incorporating pyridyl-1,2,4-triazole and phosphine ligands

2021 ◽  
Author(s):  
Ángel D. Hernández Mejías ◽  
Alexandre Poirot ◽  
Meriem Rmili ◽  
Nadine Leygue ◽  
Mariusz Wolff ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Colour Change ◽  
Phosphine Ligands

In this new Re(i) PhotoCORM, the efficient photoproduction of carbon monoxide is visualized through a strong colour change of the emitted phosphorescence.

Rhodium-Catalyzed, Phosphorus(III)-Directed Hydroarylation of Internal Alkynes: Facile and Efficient Access to New Phosphine Ligands

Synlett ◽  
2020 ◽  
Author(s):  
Minyan Wang ◽  
Zhuangzhi Shi ◽  
Huanhuan Luo ◽  
Dawei Wang
Keyword(s):  
High Selectivity ◽  
Enantiomeric Excess ◽  
Phosphine Ligands ◽  
Rapid Construction ◽  
Efficient Access ◽  
Internal Alkynes ◽  
Great Progress ◽  
Chiral Phosphine Ligands ◽  
Optimized Conditions ◽  
Made In

AbstractOrganophosphines are an important class of ligands widely used in organic chemistry. Although great progress has recently been made in the rapid construction of new phosphines through Rh- or Ru-catalyzed C–H bond functionalizations, synthetic access to more diverse phosphines remains a challenge. We describe an efficient process for the rhodium-catalyzed phosphorus(III)-directed hydroarylation of internal alkynes to generate various alkenylated and 2′,6′-dialkenylated biarylphosphines with high selectivity. A range of diverse alkynes and phosphines were effectively prepared with broad functional-group compatibility under the optimized conditions. In addition, the developed protocol can be extended to modify chiral phosphine ligands, providing enantioenriched alkenylated phosphines without erosion of the enantiomeric excess.

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