258331-09-8Relevant academic research and scientific papers
Unexpected Elasticity in Assemblies of Glassy Supra-Nanoparticle Clusters
Yin, Jia-Fu,Zheng, Zhao,Yang, Junsheng,Liu, Yuchu,Cai, Linkun,Guo, Qing-Yun,Li, Mu,Li, Xinpei,Sun, Tao Lin,Liu, Geng Xin,Huang, Caili,Cheng, Stephen Z. D.,Russell, Thomas P.,Yin, Panchao
, p. 4894 - 4900 (2021)
Granular materials, composed of densely packed particles, are known to possess unique mechanical properties that are highly dependent on the surface structure of the particles. A microscopic understanding of the structure-property relationship in these systems remains unclear. Here, supra-nanoparticle clusters (SNPCs) with precise structures are developed as model systems to elucidate the unexpected elastic behaviors. SNPCs are prepared by coordination-driven assembly of polyhedral oligomeric silsesquioxane (POSS) with metal-organic polyhedron (MOP). Due to the disparity in sizes, the POSS-MOP assemblies, like their classic nanoparticles counterparts, ordering is suppressed, and the POSS-MOP mixtures will vitrify or jam as a function of decreasing temperature. An unexpected elasticity is observed for the SNPC assemblies with a high modulus that is maintained at temperatures far beyond the glass transition temperature. From studies on the dynamics of the hierarchical structures of SNPCs and molecular dynamic simulation, the elasticity has its origins in the interpenetration of POSS-ended arms. The physical molecular interpenetration and inter-locking phenomenon favors the convenient solution or pressing processing of the novel cluster-based elastomers.
Regulating competing supramolecular interactions using ligand concentration
Teunissen, Abraham J. P.,Paffen, Tim F. E.,Ercolani, Gianfranco,De Greef, Tom F. A.,Meijer
supporting information, p. 6852 - 6860 (2016/06/14)
The complexity of biomolecular systems inevitably leads to a degree of competition between the noncovalent interactions involved. However, the outcome of biological processes is generally very well-defined often due to the competition of these interaction
Synthesis of fullerene-stoppered rotaxanes bearing ferrocene groups on the macrocycle
Mateo-Alonso, Aurelio,Prato, Maurizio
experimental part, p. 1324 - 1332 (2010/04/29)
The synthesis, characterisation and behaviour of a series of rotaxanes containing a fulleropyrrolidine stopper and two ferrocene moieties on the macrocycle is reported. Remarkably, the presence of large and bulky ferrocene groups does not interfere either in the synthesis or in the translocation of the macrocycle induced by π-π interactions between the macrocycle and the fullerene. The synthetic routes developed can also be applied to the preparation of rotaxane scaffolds that can be complexed to [Ru(CO)TPP] by axial coordination. Overall, the synthetic routes presented herein provide an efficient way to prepare a variety of rotaxanes and molecular shuttles with potential applications in different fields.
Mechanism of Site-Directed Protein Cross-Linking. Protein-Directed Selectivity in Reactions of Hemoglobin with Aryl Trimesates
Kluger, Ronald,de Stefano, Vittorio
, p. 214 - 219 (2007/10/03)
Site-directed cross-linking of hemoglobin has become an efficient way to produce a structurally defined altered protein with desirable functional properties. The reagent trimesoyl tris(3,5-dibromosalicylate) (1) introduces a bis amide cross-link derived from the ∈-amino groups of the side chains of the two β-Lys-82 residues in human hemoglobin. The basis of its specificity was investigated using a set of analogues of 1 (2-12). There are marked differences in the reaction patterns of these compounds with amino groups in hemoglobin compared to reactions with n-propylamine. The compounds that effectively modify the protein contain a carboxyl group ortho to the phenolic oxygen of the ester, while materials with meta or para carboxyl groups give little or no reaction. In contrast, the reactions with n-propylamine are slowest with the ortho carboxyl materials. Addition of the unreactive compound 5 to a solution containing hemoglobin reduces the ability of 1 to modify the protein, showing that the unreactive compound binds but does not react. On the basis of these observations and the known reaction patterns of salicylates, it is clear that the environment in the protein controls the reaction, regardless of the inherent reactivity of the reagent. We propose that the carboxyl group positions the reagent critically within the protein. Only the ortho arrangement permits transfer of the acyl function to the nucleophile.
