Search results for "Fulvene"
showing 10 items of 14 documents
Structural, electronic and energetic effects in heterocyclic fluorene derivatives fused with a fulvene unit
2019
Abstract A set of 36 heterocyclic (B, N and O) fluorene (C) derivatives fused in nine ways with fulvene ring have been analyzed by means of different local aromaticity criteria. Molecular geometry of analyzed compounds were optimized at B3LYP/6-311++G(2d,2p) level of theory. The evaluation of the local aromaticity has been carried out through the use of the geometry-based harmonic oscillator model of aromaticity (HOMA) and the magnetism-based zz‐component of the nucleus independent chemical shifts calculated 1 A above the ring center (NICS1zz) indices as well as one aromaticity index derived from the Quantum Theory Atoms in Molecules (QTAIM), i.e. the para-delocalization index (PDI). Additi…
π-Stacked polymers in drug delivery applications
2016
Abstract Polybenzofulvenes are π-stacked polymers, which can be synthesized by spontaneous polymerization of the corresponding monomers without the use of catalysts or initiators. Therefore, they can be obtained completely free from byproducts, impurities, or harmful substances. The absence of any relevant toxic effects and cell viability impairments allows PEGylated polybenzofulvene brushes to be potentially functional in a wide range of biological, biomedical, and biotechnological applications. Moreover, the properties of these polymers, in terms of interaction with pharmacological active agents and the ability to self-assemble into nanoaggregates or a quite compact physical gel useful as…
Scope and Limitations of Baird's Theory on Triplet State Aromaticity: Application to the Tuning of Singlet–Triplet Energy Gaps in Fulvenes
2007
Utilizing Baird's theory on triplet state aromaticity, we show that the singlet-triplet energy gaps (DeltaE(ST)) of pentafulvenes are easily varied through substitution by as much as 36 kcal mol(-1). This exploits the fact that fulvenes act as aromatic chameleons in which the dipoles reverse on going from the singlet ground state (S(0)) to the lowest pipi* triplet state (T1); thus, their electron distributions are adapted so as to achieve some aromaticity in both states. The results are based on quantum chemical calculations with the OLYP density functional theory method and the CASPT2 ab initio method, as well as spectroscopic determination of DeltaE(ST) by triplet sensitization. The findi…
PEG-benzofulvene copolymer hydrogels for antibody delivery.
2010
A new amphiphilic copolymer have been synthesized starting from the hydrosoluble polyaspartylhydrazide (PAHy) polymer, by grafting both hydrophilic PEG(2000) chains and hydrophobic palmitic acid (C(16)) moieties on polymer backbone, and the structure of obtained PAHy-PEG(2000)-C(16) copolymer have been characterized by 2D (1)H/(13)C NMR experiments. PAHy-PEG(2000)-C(16) copolymer showed the ability of self-assembling in aqueous media giving a core-shell structure and resulted potentially useful for encapsulating and dissolving hydrophobic drug. The formation of micellar core-shell structure has been investigated by 2D (1)H NMR NOESY experiments. The presence of cross-peaks for protons of C(…
Design and development of hyaluronan-functionalized polybenzofulvene nanoparticles as CD44 receptor mediated drug delivery system
2017
A tri-component polymer brush (TCPB), composed of a polybenzofulvene copolymer bearing low molecular weight hyaluronic acid (HA) on the surface of its cylindrical brush-like backbone and oligo-PEG fractions, was employed in the preparation of 350Â nm nanostructured drug delivery systems capable of delivering the anticancer drug doxorubicin. The obtained drug delivery systems were characterized on the basis of drug loading and release, dimensions and zeta potential, morphology and in vitro cell activity, and uptake on three different human cell lines, namely the bronchial epithelial 16HBE, the breast adenocarcinoma MCF-7, and the colon cancer HCT116 cells. Finally, the ability of doxorubicin…
Polybenzofulvene derivatives bearing dynamic binding sites as potential anticancer drug delivery systems.
2020
In order to obtain new advanced functional materials capable of recognizing drug molecules, the polybenzofulvene backbone of molecular brush poly-6-MOEG-9-TM-BF3k has been functionalized with a “synthetic dynamic receptor” composed of two 1-adamantylurea moieties linked together by means of a dipropyleneamino bridge as in Meijer's bis(adamantylurea) pincer (BAUP). This functional material, bearing synthetic receptors potentially capable of recognizing/loading and then delivering drug molecules, was used to prepare colloidal drug delivery systems (by means of soft interaction with BAUP) for delivering the model anti-cancer drug doxorubicin (DOXO). The resulting nanostructured drug delivery s…
Evaluation of thermoresponsive properties and biocompatibility of polybenzofulvene aggregates for leuprolide delivery
2012
Abstract In this study, a polybenzofulvene derivative named poly-6-MOEG-9-BF3k, was evaluated as polymeric material for the production of injectable thermoresponsive nano-aggregates able to load low molecular weight peptidic drug, like the anticancer leuprolide. Thermoresponsive behavior of poly-6-MOEG-9-BF3k was studied in aqueous media by evaluating scattering intensity variations by means of DLS in function of temperature. Zeta potential measurements and SEM observations were also carried out. Moreover, critical aggregation temperature of the poly-6-MOEG-9-BF3k polymer was evaluated by pyrene fluorescence analysis. Then, the ability of prepared thermoresponsive aggregates to protect this…
Densely PEGylated polybenzofulvene brushes for potential applications in drug encapsulation
2018
The technique of grafting side chains onto a linear polymeric backbone is commonly used to confer to the new polymeric material with desired properties, such as tunable solubility, ionic charge, biocompatibility, or specific interactions with biological systems. In this paper, two new polybenzofulvene backbones were assembled by spontaneous polymerization of the appropriate benzofulvene monomers (4,6-PO-BF3k and 4&rsquo
Novel benzofulvenes-based polymers: Characterization and employment in flexible electrochromic devices
2014
Benzofulvenes-based monomers have been synthesized for the first time and have been polymerized by means of electrochemical methods onto different electrodic materials. Morphological investigation has been performed by using SEM; electrical and optical properties have been studied by means of both cyclic voltammetry, optical absorption and spectroelectrochemical techniques. Finally, solid state electrochromic devices have been fabricated. They have displayed high optical contrast.
Thermal Rearrangements of Perchlorohexatrienes-Structures and Experimental and Theoretical Evaluation of Pathways to Isomerization and Cyclization
2009
We have prepared trans- (1) and cis-octachloro-1,3,5-hexatriene (2) by known routes and studied their thermal behavior experimentally and theoretically by ab initio calculations. The three double bonds in 1 and 2 are completely decoupled due to steric hindrance by the eight Cls, as indicated by calculations as well as the single-crystal X-ray structure of 1. The cis isomer 2 can be isomerized to the trans isomer 1 by heating it to 220–250 °C either neat or dissolved in high-boiling solvents, leading to a roughly 2:1 mixture of trans and cis isomers. Calculations at several different levels of theory predict 1 and 2 to be isoenergetic within 2 kJ mol–1. Unimolecular cis/trans isomerization i…