An FT-IRRAS study of nitrophenyl mono- and multilayers electro-deposited on gold by reduction of the diazonium salt

Formation of an organometallic junction by direct bonding of 4-nitrobenzene monolayer on gold surface by diazonium chemistry has been demonstrated by Fourier transform reflection-absorption spectroscopy with s- and p-polarized radiation.     

Facile synthesis of two oxocan derivatives using some chemical strategies

There are several studies for the synthesis of oxacycle derivatives using some reagents which require special conditions have been reported. The aim of this study was to synthesize two oxocan derivatives from either imidazole or 2-methylimidazole. The chemical structure was evaluated through both ¹H NMR and ¹³C NMR spectroscopic analysis. The results showed a moderate yielding from oxocan derivatives. It should be mentioned that reagents used in this investigation are not expensive and do not require special conditions for handling.     

Salt‐Induced Adaptation of a Dynamic Combinatorial Library of Pseudopeptidic Macrocycles: Unraveling the Electrostatic Effects in Mixed Aqueous Media

Dynamic combinatorial libraries are powerful systems for studying adaptive behaviors and relationships, as models of more complex molecular networks. With this aim, we set up a chemically diverse dynamic library of pseudopeptidic macrocycles containing amino‐acid side chains with differently charged residues (negative, positive, and neutral). The responsive ability of this complex library upon the increase of the ionic strength has been thoroughly studied. The families of the macrocyclic members concentrating charges of the same sign showed a large increase in its proportion as the ionic strength increases, whereas those with residues of opposite charges showed the reverse behavior. This observation suggested an electrostatic shielding effect of the salt within the library of macrocycles. The top‐down deconvolution of the library allowed us to obtain the fundamental thermodynamic information connecting the library members (exchange equilibrium constants), as well as to parameterize the adaptation to the external stimulus. We also visualized the physicochemical driving forces for the process by structural analysis using NMR spectroscopy and molecular modeling. This knowledge permitted the full understanding of the whole dynamic library and also the de novo design of dynamic chemical systems with tailored co‐adaptive relationships, containing competing or cooperating species. This study highlights the utility of dynamic combinatorial libraries in the emerging field of systems chemistry.     

Stimuli‐responsive antifouling polyisobutylene‐based biomaterials via modular surface functionalization

This article demonstrates a new, modular approach to surface functionalization that harnesses chain entanglement. A layer of functionalized polyisobutylene, (PIB)‐ω, where ω = ‐OH, ‐thymine (T), ‐hexaethylene glycol (HEG), poly(ethylene glycol) (‐PEG‐OH), methoxy‐functionalized poly(ethylene glycol) (‐PEG‐OCH₃), and ‐tetraethylene glycol‐α‐lipoate (TEG‐αL) was adhered to PIB‐based thermoplastic elastomer (TPE) surfaces. X‐ray photoelectron spectroscopy (XPS) at angles ranging from 20° to 75° showed decreasing polar group concentration with increasing penetration depth, confirming segregation of polar groups toward the surface. Water contact angle (WCA) of the PIB‐based TPE dropped from 95° to 79°?83° upon coating, and soaking in water for 24 h further decreased the WCA. Dynamic WCA measurements showed 40–30° receding angles, showing that stimulus from an aqueous environment elicits enrichment of polar groups on the surface. Fibrinogen (Fg) adsorption on the various surfaces was quantified using surface plasmon resonance (SPR). Static and dynamic WCA did not vary significantly among TPE + PIB‐ω surfaces, but there were dramatic differences in Fg adsorption: 256 ng/cm² was measured on the native TPE, which dropped to 40 and 22 ng/cm² on PIB‐PEG‐OCH₃ and PIB‐PEG‐OH‐coated surfaces. PIB‐TEG‐αL‐coated surfaces presented the lowest Fg adsorption with 14 ng/cm². © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 1742–1749     

Polyaniline nanostructure electrode: morphological control by a hybrid template

Journal of Solid State Electrochemistry - We report here a novel approach to the template-assisted electrochemical synthesis of vertically aligned polyaniline (PANI) nanostructure surface arrays....