24574-05-8Relevant academic research and scientific papers
Synthesis and photophysics of new pyridyl end-capped 3D-dithia[3.3]paracyclophane-based Janus tectons: Surface-confined self-assembly of their model pedestal on HOPG
Attias, A.-J.,Auffray, M.,Charra, F.,Kreher, D.,Mathevet, F.,Sosa Vargas, L.
, p. 7665 - 7674 (2020/06/10)
Surface-confined supramolecular self-assembly is currently a promising strategy to create well-organised 2D-networks on conducting surfaces. However, using such substrates tends to quench any electronic properties of the adsorbed molecules. In this context, new pyridyl end-capped 3D-dithia[3.3]paracyclophane-based molecules were designed, along with their model compound (pedestal), with the objective of self-assembling these tectons on any substrate. The synthesis of these new molecules was not straightforward and is consequently described in detail. Once the materials were successfully isolated, their optoelectronic properties were investigated to study potential non-covalent interactions: through pH-dependent absorption and emission measurements, and infra-red spectrometry. We evidenced that both ionic bonding and coordination bonding are compatible with the molecules design. Finally, preliminary scanning tunneling microscopy (STM) studies were performed to study the supramolecular self-assembly properties of the model lower-deck (pedestal) on highly oriented pyrolytic graphite (HOPG): we observed a quasi-square lattice of self-assembled 2D-networks that appear to form independently of the underlying HOPG lattice.
Stereoretentive Ring-Opening Metathesis Polymerization to Access All- cis Poly(p-phenylenevinylene)s with Living Characteristics
Hsu, Ting-Wei,Kim, Cheoljae,Michaudel, Quentin
supporting information, p. 11983 - 11987 (2020/08/06)
Poly(p-phenylenevinylene)s (PPVs), a staple of the conductive polymer family, consist of alternating alkene and phenyl groups in conjugation. The physical properties of this organic material are intimately linked to the cis/trans configuration of the alkene groups. While many synthetic methods afford PPVs with all-trans stereochemistry, very few deliver the all-cis congeners. We report herein a synthesis of all-cis PPVs with living characteristics via stereoretentive ring-opening metathesis polymerization (ROMP). Exquisite catalyst control allows for the preparation of homopolymers or diblock copolymers with perfect stereoselectivity, narrow dispersities, and predictable average molar masses. All-cis PPVs can then serve as light-responsive polymers through clean photoisomerization of the stilbenoid units.
Co-crystal formation between 2-amino-4,6-dimethylpyrimidine and new p-xylylene-bis(thioacetic) acid
Ostasz,Lyszczek,Mazur,Tarasiuk
, p. 10262 - 10272 (2015/02/19)
Novel p-xylylene-bis(thioacetic) acid (p-XBTA) and its co-crystals with 2-amino-4,6-dimethylpyrimidine (DMP) have been synthesized and characterized by single-crystal X-ray diffraction, infrared spectroscopy and thermal analysis methods (TG/DSC). Depending on the crystallization conditions, three different multicomponent crystal forms have been isolated with various chemical compositions and stoichiometries of the co-formers. The ATR-FTIR spectra of the co-crystals display the stretching vibration bands for the co-formers with associated shifts confirming the formation of new phases. DSC and TG were used to reveal the relative stabilities of new solids compared to those of the co-formers.
Synthesis of three tethered trisaccharides to probe entropy contributions in carbohydrate-protein interactions
Zhang, Ping,Bundle, David R.
, p. 189 - 208 (2007/10/03)
Crystal structure data show that the branched trisaccharide 1 constitutes the complete antigenic determinant of the Salmonella serogroup B antigen that is recognized by monoclonal antibody SE155.4. In an effort to characterize the entropic costs associated with immobilization of glycosidic torsional angles in the bound state, three distinct intramolecularly tethered analogues of this trisaccharide 2-4 have been synthesized. Two trisaccharides are tethered by a methylene acetal via the O-2 position of the 3,6-dideoxy-hexose, abequose to either O-2 of galactose (2) or O-4 of mannose (3). The third tether, α,α'-di-thio-p-xylene, spans the C-6 atoms of the mannose and galactose residues to create trisaccharide 4. The acetal tethers of 2 and 3 span hydroxyl centers that are known to be involved in intramolecular sugar-sugar hydrogens bonds, but both trisaccharides are biologically inactive due to distorted conformations that cannot be accommodated in the antibody binding site. Trisaccharide 4 is active since both hydroxymethyl groups of galactose and mannose are solvent exposed in the bound state and the constrained conformation of 4 is virtually superimposable on the bound conformation of 1. Despite the retained complimentary and significant reduction of torsional flexibility, trisaccharide 4 exhibits a ΔG° = -7.6 kcal mol-1 compared to ΔG° = -7.1 kcal mol-1 for 1. The modest free energy gain for the tethered trisaccharide 4 arises from a small entropy gain (TΔΔS = 0.3 kcal mol-1) and an even smaller enthalpic change (ΔΔH = -0.2 kcal mol-1).
Synthesis of a Novel Series of Arylmethylisothiouronium Derivatives
Tal, Daniel M.,Karlish, Steven J. D.
, p. 3823 - 3830 (2007/10/02)
The bromination by N-bromosucciniminde of various mesitylene derivatives, to produce arylmethyl bromides was compared in different reaction conditions.These compounds are intermediates in the synthesis of arylmethylisothiouronium bromide salts, achieved b
Thiodialkylenyl-5-bistetrazoles and Thiouronium Salts as Potential Slow Acting Anticancer Agents
Kumar, Anil,Tilak, B. D.
, p. 599 - 601 (2007/10/02)
A series of Thiodialkylenyl-5-bistetrazoles and Thiouronium salts have been synthesised.The above compounds in comparison with thiodiglycollic and thiodipropionic acids and thiophene-2,5-bisdimethylenylthiouronium dichloride are expected to have prolonged anticancer effect in vivo.
