Search results for "405"

Self-assembly of M4L4tetrahedral cages incorporating pendant PS and PSe functionalised ligands

2019

Herein, the synthesis of metal–organic tetrahedral cages featuring flexible thio- and selenophosphate-based ligands is described. The cages were prepared by sub-component self-assembly of AP(OC6H4NH2-4)3 (A = S, Se) or SP(SC6H4NH2-4)3, 2-pyridinecarboxaldehyde, and either Fe[BF4]2 or Co[BF4]2. Preliminary host–guest studies into the ability of the pendant PS and PSe groups to interact with suitable substrates will be discussed.

Structure effects induced by high mechanical compaction of STAM-17-OEt MOF powders

2021

Financial support by PJ-RIC-FFABR_2017 and the EPSRC grant EPSRC industrial CASE award (grant EP/N50936X/1) are acknowledged. The research programme Nanoporous materials (P1-0021) financially supported by Slovenian Research Agency (ARRS) is acknowledged as well. Metal-organic frameworks (MOFs) are promising materials for many potential applications, spacing from gas storage to catalysis. However, the powder form of which they are generally made is not suitable, mainly because of the low packing density. Powder compaction is therefore necessary, but also challenging because of their typical mechanical fragility. Indeed, generally, they undergo irreversibly damages upon densification processe…

Enhanced NiO Dispersion on a High Surface Area Pillared Heterostructure Covered by Niobium Leads to Optimal Behaviour in the Oxidative Dehydrogenatio…

2020

[EN] A Nb-containing siliceous porous clay heterostructure (PCH) with Nb contents from 0 to 30 wt %) was prepared from a bentonite and used as support in the preparation of supported NiO catalysts with NiO loading from 15 to 80 wt %. Supports and NiO-containing catalysts were characterised by several physicochemical techniques and tested in the oxidative dehydrogenation (ODH) of ethane. The characterisation studies on Nb-containing supports showed the presence of well-anchored Nb(5+)species without the formation of Nb(2)O(5)crystals. High dispersion of nickel oxide with low crystallinity was observed for the Nb-containing PCH supports. In addition, when NiO is supported on these Nb-containi…

Synthesis of 2-Aminothiazole Derivatives in Easy Two-Step, One-Pot Reaction

2018

Reactivity of [1,2,3]Triazolo[1,5-a]pyridines as 1,3-dipoles

2016

Abstract We have studied the reactions between [1,2,3]Triazolo[1,5- a ]pyridines 1a,b,c and electron-deficient ethylenes in different conditions. Compounds 1a and 1b react with ethyl propiolate, and dimethyl acetylene dicarboxylate giving a new class of biaryl compounds pyridyl pyrazoles, and with ethyl acrylate giving pyridyl cyclopropanes. Compound 1c did not give any product in the studied conditions. A proposal of mechanism of these reactions is done in which the triazolopyridines act as 1,3-dipoles giving 1,3-dipolar cycloadditions.

Unsymmetrically Substituted Bis(phosphino)Ferrocenes Triggering Through-Space 31(P, P′)-Nuclear Spin Couplings and Encapsulating Coinage Metal Cations

2021

International audience; We describe unsymmetrically substituted di-tert-butylated 1,1'-bis(phosphino)ferrocenes, with phosphino substituents R = [5-methyl]-2-furyl = Fu, and R' = phenyl (4a), i-propyl (4b). A modular synthetic approach was applied from the di-tert-butylated ferrocene platform (1), which lead to the formation of new diphosphines by using 1,1'bis(diiodo)-3,3'-bis(tert-butyl)ferrocene (2) as synthetic precursor. In contrast to the cousin non-alkylated unsymmetrically substituted diphosphino-ferrocenes which were reported up to now, these diphosphines showed strong (31 P, P')nonbonded (" ug-p e") nuclear spin-spin coupling. The strength of such internuclear spin-spin coupling c…

X-ray, conformation and electronic structures of 1-nitropyrrolidine

2016

Abstract The chemistry of pyrrolidine compounds has drawn much attention because of their biological activities. The crystal and molecular structure of 1-nitropyrrolidine (C4H8NNO2) at 150K, along with calculated structures (DFT and MP2), are reported herein. In the solid-state, the asymmetric part of the unit cell is composed of one quartermolecule at the position of two perpendicular mirror planes and the five-membered ring is disordered over a mirror plane, revealing the twisted conformation. Both geometries suggest slight sp3 hybridization of the amine nitrogen atom. The non-planar geometry suggests the lack of conjugation of the amine nitrogen lone pair with the nitro group, however th…

Facile synthesis of annulated heterocyclic benzo[kl]acridine derivatives via one-pot N–H/C–H coupling

2016

An efficient N–H/C–H one-pot coupling method for the preparation of benzo[kl]acridines has been developed based on palladium-catalyzed domino synthesis. Using commercially available starting materials such as dihalonaphthalenes and diphenylamines, and combining amination with catalysts for C–H activation, up to 95% overall yield can be achieved.

Diels–Alder reaction on perylenediimides: synthesis and theoretical study of core-expanded diimides

2019

A one-step reaction for the fusion of aromatic rings to one or both bay areas of perylenediimides using benzynes is presented. Yields as high as 70% for naphthoperylenendiimide 2 and 80% for dibenzocoronenediimide 3 are obtained. The reaction is also carried out using substituted benzynes, heteroaromatic benzynes and substituted perylenediimides. A combined experimental/theoretical approach, based on measuring redox and absorption/emission properties and performing density functional theory calculations, indicates that increasing the π-skeleton of PDIs transversally leads to significant and unexpected changes in the electronic, redox and optical properties. The observed trends are rationali…

Understanding the Participation of Fluorinated Azomethine Ylides in Carbenoid-Type [3 + 2] Cycloaddition Reactions with Ynal Systems: A Molecular Ele…

2021

The carbenoid-type (cb-type) 32CA reaction of 1,1-difluoroated azomethine ylide (DFAY) with phenylpropynal has been studied using the molecular electron density theory (MEDT). Electron localization function (ELF) characterizes DFAY as a carbenoid species participating in cb-type 32CA reactions. The supernucleophilic character of DFAY and the strong electrophilic character of the ynal cause this polar 32CA reaction to have an unappreciable barrier; the reaction, which is highly exothermic, presents total chemo- and regioselectivity. ELF topological analysis of the bonding changes along the reaction establishes its non-concerted two-stage one-step mechanism, in which the nucleophilic attack o…