Conjugated Nanohoops with Dibenzo[a,e]pentalenes as Non-alternant and Antiaromatic π-Systems

Conjugated nanohoops are excellent candidates to study structure-property relationships, as optoelectronic materials and as hosts for supramolecular chemistry. While carbon nanohoops containing aromatics are well studied, antiaromatic units had not been incorporated until recently by our group using dibenzo[a,e]pentalene (DBP). The non-alternant electronic character of the DBP units significantly influences the optoelectronic properties of such nanohoops. We herein summarize our synthetic strategies to DBP-containing nanohoops, their structural and electronic properties, chirality and host-guest chemistry. We demonstrate how incorporating antiaromatic units leads to unique properties and opens new synthetic avenues, making such nanohoops attractive as potential electronic materials.

Ru@hyperbranched Polymer for Hydrogenation of Levulinic Acid to Gamma-Valerolactone: The Role of the Catalyst Support

Hydrogenation of levulinic acid (LA) obtained from cellulose biomass is a promising path for production of γ-valerolactone (GVL)—a component of biofuel. In this work, we developed Ru nanoparticle containing nanocomposites based on hyperbranched pyridylphenylene polymer, serving as multiligand and stabilizing matrix. The functionalization of the nanocomposite with sulfuric acid significantly enhances the activity of the catalyst in the selective hydrogenation of LA to GVL and allows the reaction to proceed under mild reaction conditions (100 °C, 2 MPa of H2) in water and low catalyst loading (0.016 mol.%) with a quantitative yield of GVL and selectivity up to 100%. The catalysts were successfully reused four times without a significant loss of activity. A comprehensive physicochemical characterization of the catalysts allowed us to assess structure-property relationships and to uncover an important role of the polymeric support in the efficient GVL synthesis.

Progress on Exploring the Luminescent Properties of Organic Molecular Aggregates by Multiscale Modeling

Luminescent molecular aggregates have attracted worldwide attention because of their potential applications in many fields. The luminescent properties of organic aggregates are complicated and highly morphology-dependent, unraveling the intrinsic mechanism behind is urgent. This review summarizes recent works on investigating the structure–property relationships of organic molecular aggregates at different environments, including crystal, cocrystal, amorphous aggregate, and doped systems by multiscale modeling protocol. We aim to explore the influence of intermolecular non-covalent interactions on molecular packing and their photophysical properties and then pave the effective way to design, synthesize, and develop advanced organic luminescent materials.

Fully Fused Boron-Doped Polycyclic Aromatic Hydrocarbons: Their Synthesis, Structure–Property Relationships, and Self-Assembly Behavior in Aqueous Media

Planarized triarylboranes are attracting increasing attention not only as models of boron-doped graphenes, but also as promising materials for organic optoelectronics. In particular, polycyclic aromatic hydrocarbon (PAH) skeletons with embedded...

Miniaturized peptidomimetics and nano-vesiculation in endothelin types through probable nano-disk formation and structure property relationships of endothelins’ fragments

Endothelins (ETs), which are multi-functional-peptides with potential for antagonist-based-therapy in various physiological-malfunctionings, including cardiovascular, nephrological, oncologic, and diabetic conditions, may produce newer chemical entities and drug leads. The present study deals with molecular-modeling of the ETs’ sub-types, ET-I, II, and III to find the structure property-relationship (SPR) of the ETs, and individual fragments derived from the ET sub-type ET-I. The ETs peptidic tails’ amino acid (AA) sequence’s structural differences and similarities, various dissected fragments of the ET-I, and SPR comparison with the sarafotoxin-6b (SRT-6b), a structurally-related snake-venom, showed points of dissimilarities for their structural specifications, geometric disposition, and physico-chemical properties. The generation of miniaturized (shortened sequence) peptides towards offering peptidomimetic compounds of near- and far-values compared SPR with estimations for log P, hydration energy, and other molecular and quantitative structure activity relationship (QSAR) were based on random and ordered-fragments derived from the original ET-I AA’s sequence, and sequential distance changes in the original ET-I sequence’s chain of 1–21 AA. The feasibility of alternate and bond length parameters-based possible cysteine–cysteine cyclizations, sequence homology, AA’s positional demarcation, and presence/absence of cysteines, homology-based basic non-cysteine and cysteines-AA based cyclization, total structure and fragments end-to-end cyclizations, and geometrical analogy-based miniaturized sequence of the shorter AAs from the original ET-I sequence, together with mutated replacements with naturally constituent AAs of the ETs, and SRT-6 sequences were utilized. The major findings of the fragmented sequences, and sequences at par with the original ETs to provide structures similar to the size, volume and with molecular and electronic properties of electrostatic potential and total charge density distribution, crucial factors in receptor bindings were investigated. The SPRs, molecular properties, and QSAR values were estimated to compare and validate the findings with the known homologous compounds, ET-I, and its known and potent antagonists. The study resulted in leads of smaller and larger sizes of peptide-based compounds which may have prospects as potent antagonist and in future needs their bioactivity evaluations after the synthesis. Moreover, approach to plausible vesiculation of the ETs, and the involved processes and structural requirements, together with the molecular interactions in settling a nano-vesicle of the peptidic structure with a possible mechanism is also suggested.