499-51-4Relevant articles and documents
Thermal-healable and shape memory metallosupramolecular poly(n-butyl acrylate-co-methyl methacrylate) materials
Wang, Zhenhua,Fan, Wenru,Tong, Rui,Lu, Xili,Xia, Hesheng
, p. 25486 - 25493 (2014)
A big challenge in developing stimuli-responsive materials is to integrate multiple functionalities such as shape memory property, healable ability, recyclability into a single-component material. With this purpose, we designed a novel poly(n-butyl acrylate-co-methyl methacrylate) bearing a side group 2,6-bis(1′-methylbenzimidazolyl)pyridine ligand, which is dynamically crosslinked by the metal salt zinc trifluoromethanesulfonate to obtain the metallosupramolecular polymer. The shape recovery and healing is achieved upon application of a thermal or light stimulus due to the specific metal-ligand interactions which not only serve as an "inert" crosslink network at low temperature to produce the shape recovery, but also dissociate at high temperature for healing. The healing rate is quick and the healing efficiently is close to ～90%. the Partner Organisations 2014.
Bottom-Up Approach for the Rational Loading of Linear Oligomers and Polymers with Lanthanides
Besnard, Céline,Guénée, Laure,Mirzakhani, Mohsen,Naseri, Soroush,Nozary, Homayoun,Piguet, Claude
supporting information, p. 15529 - 15542 (2021/10/20)
The adducts between luminescent lanthanide tris(β-diketonate)s and diimine or triimine ligands have been explored exhaustively for their exceptional photophysical properties. Their formation, stability, and structures in solution, together with the design of extended metallopolymers exploiting these building blocks, remain, however, elusive. The systematic peripheral substitution of tridentate 2,6-bis(benzimidazol-2-yl)pyridine binding units (Lk = L1-L5), taken as building blocks for linear oligomers and polymers, allows a fine-tuning of their affinity toward neutral [Ln(hfa)3] (hfa = hexafluoroacetylacetonate) lanthanide containers in the [LkLn(hfa)3] adducts. Two trends emerge with (i) an unusual pronounced thermodynamic selectivity for midrange lanthanides (Ln = Eu) and (ii) an intriguing influence of remote peripheral substitutions of the benzimidazole rings on the affinity of the tridentate unit for [Ln(hfa)3]. These trends are amplified upon the connection of several tridentate binding units via their benzimidazole rings to give linear segmental dimers (L6) and trimers (L7), which are considered as models for programming linear Wolf-Type II metallopollymers. Modulation of the affinity between the terminal and central binding units in the linear multitridentate ligands deciphers the global decrease of metal-ligand binding strengths with an increase in the length of the receptors (monomer → dimer → trimer → polymer). Application of the site binding model shed light onto the origin of the variation of the thermodynamic affinities: a prerequisite for the programmed loading of a polymer backbone with luminescent lanthanide β-diketonates. Analysis of the crystal structures for these adducts reveals delicate correlations between the chemical bond lengths measured in the solid state (or bond valence parameters) and the metal-ligand affinities operating in solution.
Preparing method of 4-hydroxypyridine-2,6-dicarboxylic acid
-
Paragraph 0028-0062, (2019/10/01)
The invention relates to a preparing method of 4-hydroxypyridine-2,6-dicarboxylic acid, and belongs to the technical field of organic synthesis. According to the preparing method of the 4-hydroxypyridine-2,6-dicarboxylic acid, acetone and dimethyl oxalate are taken as raw materials, concentrated hydrochloric acid is taken as a cyclizing agent, and then an intermediate 4-pyrone-2,6-dicarboxylic acid is synthesized and reacts with ammonium hydroxide to prepare the 4-hydroxypyridine-2,6-dicarboxylic acid. In the condensation process, the temperature of a mixed liquor of acetone, dimethyl oxalateand ethyl alcohol is gradually increased until the mixed liquor is heated to 60-80 DEG C. The viscosity of a reaction mixture can be lowered, so that uniform mixing of the mixture is achieved, and theyield of the product is increased. The concentrated hydrochloric acid is added in the mixture system, after heating is conducted for a reaction, the system is cooled to 5 DEG C, and then stirring andfiltering are conducted under an ice-water bath condition. An intermediate product is prevented from being decomposed, and condensation reverse reactions are prevented. The preparing method is simplein process, the yield is 90.1 or above, the reaction time is short, the cost is low, and the economic benefit and the social benefit are obvious.
