6. Rehybridization of the Acceptor (RICT) 3908 7. Planarization of the Molecule (PICT) 3909 III. Fluorescence Spectroscopy 3909 A. Solvent Effects and the Model Compounds 3909 1. Solvent Effects on the Spectra 3909 2. Steric Effects and Model Compounds 3911 3. Bandwidths 3913 4. Isoemissive Points 3914 B. Dipole Moments 3915 C. Radiative Rates and Transition Moments 3916 1. Quantum Yields and Radiationless Deactivation Processes 3916

Structural Changes Accompanying Intramolecular Electron Transfer: Focus on Twisted Intramolecular Charge-Transfer States and Structures

A review was presented to demonstrate a historical description of the synthesis of light-emitting conjugated polymers for applications in electroluminescent devices. Electroluminescence (EL) was first reported in poly(para-phenylene vinylene) (PPV) in 1990 and researchers continued to make significant efforts to develop conjugated materials as the active units in light-emitting devices (LED) to be used in display applications. Conjugated oligomers were used as luminescent materials and as models for conjugated polymers in the review. Oligomers were used to demonstrate a structure and property relationship to determine a key polymer property or to demonstrate a technique that was to be applied to polymers. The review focused on demonstrating the way polymer structures were made and the way their properties were controlled by intelligent and rational and synthetic design.

Synthesis of Light-Emitting Conjugated Polymers for Applications in Electroluminescent Devices

Cyclodextrins as pharmaceutical solubilizers.

In this review, we describe the recent advances in supramolecular helical assemblies formed from chiral and achiral small molecules, oligomers (foldamers), and helical and nonhelical polymers from the viewpoints of their formations with unique chiral phenomena, such as amplification of chirality during the dynamic helically assembled processes, properties, and specific functionalities, some of which have not been observed in or achieved by biological systems. In addition, a brief historical overview of the helical assemblies of small molecules and remarkable progress in the synthesis of single-stranded and multistranded helical foldamers and polymers, their properties, structures, and functions, mainly since 2009, will also be described.

Supramolecular Helical Systems: Helical Assemblies of Small Molecules, Foldamers, and Polymers with Chiral Amplification and Their Functions

This review focuses on classifying different types of long wavelength absorbing BODIPY dyes based on the wide range of structural modification methods that have been adopted, and on tabulating their spectral and photophysical properties. The structure–property relationships are analyzed in depth with reference to molecular modeling calculations, so that the effectiveness of the different structural modification strategies for shifting the main BODIPY spectral bands to longer wavelengths can be readily compared, along with their effects on the fluorescence quantum yield (ΦF) values. This should facilitate the future rational design of red/NIR region BODIPY dyes for a wide range of different applications.

Structural modification strategies for the rational design of red/NIR region BODIPYs

PNIPAM hydrogels functionalized with gold nanoparticles were prepared by making use of catechol redox chemistry. For this purpose catechol groups were introduced in the PNIPAM network during the cross-linking polymerization process (PNIPAM–catecholx hydrogel). These groups act as reducing agents of HAuCl4, which enables the functionalization of the PNIPAM with gold nanoparticles (PNIPAM–catecholx@Au hydrogel). The rheological study shows that catechol groups reinforce the hydrogel structure. A stronger effect was observed after the functionalization of the hydrogel with gold nanoparticles. This influence could be easily observed since the variation of G′ with the MBA mole fraction was fitted to a power-law expression G′ ∼ xMBAa, with a = 1.6 for PNIPAMx hydrogels, a = 2.3 for PNIMPAM–catecholx hydrogels and a = 3.2 for PNIMPAM–catecholx@Au hydrogels. The capability of the PNIPAM–catecholx@Au hydrogel to act as a tunable catalyst was demonstrated with a model reduction reaction. The half-lifetime at 25 °C ...

Poly(N-isopropylacrylamide)/Gold Hybrid Hydrogels Prepared by Catechol Redox Chemistry. Characterization and Smart Tunable Catalytic Activity

Steady-state fluorescence and molecular mechanics have been used to study the inclusion complexes of dimethyl 2,6-naphthalenedicarboxylate (DMN) with α- and β-cyclodextrins (CDs). Emission spectra of DMN show two bands whose ratio is very sensitive to the medium polarity. From the change of this ratio with CD concentration and temperature, the stoichiometry, the formation constants, and the changes of enthalpy and entropy upon inclusion of complexes formed were obtained. Stoichiometry depends on the host CD used. The estimated formation constants at 25 °C were (8.2 ± 0.6) × 105 M-2 for DMN:αCD2 and 1311 ± 57 M-1 for DMN:βCD. A dependence of the thermodynamic parameters ΔH° and ΔS° on the temperature was also found. Both complexes showed a negative ΔCp°. In addition, DMN seems to be a good probe for estimating microenvironmental polarity. Molecular mechanics calculations were also employed to study the formation of 1:1 and 1:2 complexes of DMN with both α- and βCDs. The study was mainly performed in the pr...

Inclusion Complexes of Dimethyl 2,6-Naphthalenedicarboxylate with α- and β-Cyclodextrins in Aqueous Medium: Thermodynamics and Molecular Mechanics Studies

Molecular Mechanics Study of the Inclusion Complexes of 2-Methyl Naphthoate with α- and β-Cyclodextrins

The synthesis of dipyridopyrazole and pyridopyrazolopyrazine derivatives—both of which incorporate a 3-aryl moiety—can be achieved in moderate yields by intramolecular radical arylation of pyridinium N-aminides using tris(trimethylsilyl)silane and azobisisobutyronitrile. Improved results were obtained on using Pd direct arylation in conjunction with microwave irradiation. A preliminary study into the fluorescent properties of the target compounds is also reported.

A new class of pyrazolopyridine nucleus with fluorescent properties, obtained through either a radical or a Pd arylation pathway from N-azinylpyridinium N-aminides.

Inclusion Complexes of Chain Molecules with Cycloamyloses III. Molecular Dynamics Simulations of Polyrotaxanes Formed by Poly(propylene glycol) and β-Cyclodextrins

/pdf/inclusion-complexes-of-chain-molecules-with-cycloamyloses-lvuvwvra9m.pdf

Francisco Mendicuti

Papers

Poly(N-isopropylacrylamide)/Gold Hybrid Hydrogels Prepared by Catechol Redox Chemistry. Characterization and Smart Tunable Catalytic Activity

Inclusion Complexes of Dimethyl 2,6-Naphthalenedicarboxylate with α- and β-Cyclodextrins in Aqueous Medium: Thermodynamics and Molecular Mechanics Studies

Molecular Mechanics Study of the Inclusion Complexes of 2-Methyl Naphthoate with α- and β-Cyclodextrins

A new class of pyrazolopyridine nucleus with fluorescent properties, obtained through either a radical or a Pd arylation pathway from N-azinylpyridinium N-aminides.

Inclusion Complexes of Chain Molecules with Cycloamyloses III. Molecular Dynamics Simulations of Polyrotaxanes Formed by Poly(propylene glycol) and β-Cyclodextrins