Twofold 6π-Electrocyclization as a Route Toward Multi-Heteroatom-Doped Nanographenes Built on a 1,4-Dihydropyrrolo[3,2-b]pyrrole Core.

Here we present a highly versatile synthetic strategy based on twofold 6π-electrocyclization accompanied with HBr elimination as a novel approach towards centrosymmetric multi-heteroatom-doped nanographenes build around an electron-rich 1,4-dihydropyrrolo[3,2-b]pyrrole core. A straightforward synthesis from readily available substrates offers a unique possibility of fusing the 1,4-dihydropyrrolo[3,2-b]pyrrole subunit not only with carbocyclic building blocks, such as electron-deficient phenanthrenes, chrysenes, or [4]helicenes, but also with heterocyclic systems, such as benzo[b]furan and 5-thiatruxene. The clear advantage of this strategy is that there is no requirement to assemble complex scaffolds possessing bromoaryl units since bromine atom is introduced by bromination of 1,4-dihydropyrrolo[3,2-b]pyrrole core which, because of its exceptionally electron-rich character, is straightforward reaction.

3D self-assembled polar . non-polar NiO nanoparticles nanoengineered from turbostratic Ni(OH)(NO) and ordered β-Ni(OH) intermediates.

A surfactant-free ammonia and carbamide precursor-modulated engineering of self-assembled flower-like 3D NiO nanostructures based on ordered β-Ni(OH) and turbostratic Ni(OH)(NO) nanoplate-structured intermediates is reported. By employing complementary structural and spectroscopic techniques, fundamental insights into structural and chemical transformations from intermediates to NiO nanoparticles (NPs) are provided. FTIR, Raman and DSC analyses show that the transformation of intermediates to NiO NPs involves subsequent loss of NO and OH species through a double-step phase transformation at 306 and 326 °C corresponding to the loss of free interlayer ions and HO species, respectively, followed by the loss of chemically bonded OH and NO ions.

Molecular Hydrogen Acts as a Hydrogen Bond Proton Acceptor: From Protonated Betaine Tagging to the Weakest Hydrogen Bond.

In an attempt to gain further insights into the intermolecular interactions implied by Rizzo's group's cautionary tale related to molecular tagging in infrared multiple photon dissociation (IRMPD) spectroscopy with molecular messengers [Masson, A. . 2015, 143, 104313], in the present study, we provide an in-depth analysis of the noncovalent interaction between the molecular hydrogen and protonated betaine molecule in the gas phase.

Defects Formation and Amorphization of Zn-MOF-74 Crystals by Post-Synthetic Interactions with Bidentate Adsorbates.

The controlled introduction of defects into MOFs is a powerful strategy to induce new physiochemical properties and improve their performance for target applications. Herein, we present a new strategy for defect formation and amorphization of the canonical MOF-74 frameworks based on fine-tuning of adsorbate-framework interactions in the metal congener, hence introducing structural defects. Specifically, we demonstrate that controlled interactions between the MOF and bidentate ligands adsorbed in the pores initiates defect formation and eventual amorphization of the crystal.

1,4-Dideoxy-1,4-imino-d-arabinitol (DAB) Analogues Possessing a Hydrazide Imide Moiety as Potent and Selective α-Mannosidase Inhibitors.

The synthesis of two polyhydroxylated pyrrolidines as 1,4-dideoxy-1,4-imino-d-arabinitol (DAB) analogues bearing a hydrazide moiety is described. The DAB analogues act as selective and potent inhibitors of α-mannosidase in the submicromolar concentration ranges ( values ranging from 0.23 to 1.