Search results for "bonding"

Slow magnetic relaxation in a hydrogen-bonded 2D array of mononuclear dysprosium(III) oxamates.

2013

The reaction of N-(2,6-dimethylphenyl)oxamic acid with dysprosium(III) ions in a controlled basic media afforded the first example of a mononuclear lanthanide oxamate complex exhibiting a field-induced slow magnetic relaxation behavior typical of single-ion magnets (SIMs). The hydrogen-bond-mediated self-assembly of this new bifunctional dysprosium(III) SIM in the solid state provides a unique example of 2D hydrogen-bonded polymer with a herringbone net topology.

Structural Rearrangements in Triple-Decker-Like Complexes with Mixed Group 15/16 Ligands: Synthesis and Characterization of the Redox Couple [Cp2*Fe2…

2001

The reaction of As4Se4 with stoichiometric amounts of [Cp*Fe2(CO)4] (Cp* = C5Me5) in boiling toluene forms [Cp2*Fe2As2Se2] (1) in good yield. X-ray crystallography shows 1 to have a triple-decker structure which comprises a tetraatomic mu,eta4:4-As2Se2 ligand. Density functional theory (DFT) and extended Huckel molecular orbital (EHMO) calculations confirm that the As2Se2 ligand behaves as a four-electron pi donor. Oxidation of 1 with equimolar amounts of [(C5H5)2Fe]PF6, Br2 and I2, respectively, gave compounds 2-4. According to X-ray crystallographic investigations that were carried out on 2 and 4, the oxidation state has a considerable influence on the structure of the Fe2As2Se2 core: sig…

2-Acylamino- and 2,4-bis(acylamino)pyrimidines as supramolecular synthons analysed by multiple non-covalent interactions. DFT, X-ray diffraction, and…

2012

Intermolecular interactions of ten 2-acylamino and 2,4-bis(acylamino)pyrimidines (7 of which are previously unknown) have been investigated by X-ray structural, quantum chemical (DFT), and NMR spectral methods. Especially the concentration dependencies of the (1)H NMR chemical shifts and titrations with other molecules capable of multiple hydrogen bonding provided useful information regarding their association via triple or quadruple hydrogen bonding, which is controlled by the conformational preferences of 2-acylamino- and 2,4-bis(acylamino)pyrimidines. On comparison of the properties of 2-acylamino- and 2,4-bis(acylamino)pyrimidines with the corresponding pyridines, an additional nitrogen…

Structure and dynamics of dibutylphosphate/n-propylamine ionic liquid: A multi-scale theoretical study

2021

Abstract Owing to the amphiphilic nature of their constituent molecules, binary mixtures of pure liquid surfactants are usually characterized by enhanced nano-segregation and thus can exhibit interesting transport properties and complex macroscopic behavior. In this ambit it was recently shown by Turco Liveri et al. (2018) that mixtures of short aliphatic chains compounds at room temperature, such as dibutyl phosphate (DBP) and n-propylamine (PA) liquids, display ionic liquid–like behavior ascribed to phosphate-to-amine proton transfer. To gain a detailed molecular picture of the system structure and dynamics and to understand the molecular mechanisms at the basis of the observed behavior, …

Solution-processed bi-layer polythiophene–fullerene organic solar cells

2013

An ionic polymer based on a polythiophene backbone with appended imidazolium moieties was successfully implemented as a donor material in fully solution-processed efficient bi-layer solar cells prepared by the low impact meniscus coating technique. High fill factors and device reproducibility were obtained, even for ultrathin polymer layers, indicating excellent film formation properties and good compatibility with solution processing techniques. The possibility of smooth counter ion exchange, allowing solubility modification and efficiency tuning, enables exploration of new functionalities and other device architectures.

Graphene related magnetic materials: micromechanical exfoliation of 2D layered magnets based on bimetallic anilate complexes with inserted [FeIII(aca…

2015

The syntheses, structures and magnetic properties of the coordination compounds of formula [FeIII(acac2-trien)][MnIICrIII(Cl2 An)3]·(CH3CN)2 (1), [FeIII(acac2-trien)][MnIICrIII(Br2An)3]·(CH3CN)2 (2) and [GaIII(acac2-trien)][MnIICrIII(Br2An)3]·(CH3CN)2 (3) are reported. They exhibit a 2D anionic network formed by Mn(II) and Cr(III) ions linked through anilate ligands, while the [FeIII(acac2-trien)]+ or [GaIII(acac2-trien)]+ charge-compensating cations are placed inside the hexagonal channels of the 2D network, instead of being inserted in the interlamellar spacing. Thus, these crystals are formed by hybrid layers assembled through van der Waals interactions. The magnetic properties indicate …

Red-light-emitting electrochemical cell using a polypyridyl iridium(III) polymer.

2009

A deep-red phosphorescent ionic iridium(III) complex is prepared and incorporated into a polymer. Both the complex (1) and the polymer (2) were used as the single active material in solid-state light-emitting electrochemical cells (LECs). The devices built up using 1 and 2 emit in the deep-red region of the visible spectrum with CIE coordinates x = 0.710; y = 0.283 and x = 0.691; y = 0.289, respectively, making them one of the deepest-red emitting LECs reported. It is the first example of a polymeric LEC incorporating an ionic iridium complex, which exhibits increased stabilities compared with the device based on the small molecular weight complex.

Molecular Mobility in Oriented and Unoriented Membranes Based on Poly[2-(Aziridin-1-yl)ethanol]

2021

Unoriented and oriented membranes based on dendronized polymers and copolymers obtained by chemical modification of poly[2-(aziridin-1-yl) ethanol] (PAZE) with the dendron 3,4,5-tris[4-(n-dodecan-1-yloxy)benzyloxy]benzoate were considered. DSC, XRD, CP-MAS NMR and DETA, contribute to characterize the tendency to crystallize, the molecular mobility of the benzyloxy substituent, the dendritic liquid crystalline group and the clearing transition. The orientation of the mesogenic chain somewhat hindered this molecular motion, especially in the full substituted PAZE. The fragility, free volume and thermal expansion coefficients of these membranes near the glass transition are related to the orie…

1995

Redoxactive liquid crystalline (LC) side group polymers were prepared by copolymerization of liquid crystalline acrylates and ferrocene-containing acrylates. The corresponding liquid crystalline ionomers were synthesized by a reversible redox reaction. The incorporation of tetra-alkylated ferrocene derivatives leads to LC polymers with reduced redox potential. These polymers can be oxidized under mild conditions to the corresponding ionomers, which are much more stable in solution than LC ionomers containing monoalkylated ferrocenium ions. Dynamic mechanical measurements and small angle X-ray scattering (SAXS) perfomed on LC ionomers prove the existence of ionic superstructures (clusters) w…

Iron(II) Metallomesogens Exhibiting Coupled Spin State and Liquid Crystal Phase Transitions near Room Temperature

2008

Reaction of the ligand 2,2,2-tris(2-aza-3-((5-akloxy)(6-methyl)(2-pyridyl))prop-2-enyl)ethane (C n -tameMe) with Fe(X) 2 . sH 2 O salts afforded a series of spin crossover metallomesogens with general formula [Fe(C n -tame)](X) 2 . sH 2 O (s ≥ 0), with n = 6, 10, 12, 14, 16, 17, 18, or 20 and X =ClO 4 - or BF 4 -. Single crystal X-ray measurements have been performed on the [Fe(C 6 -tameMe)](ClO 4 ) 2 (C 6 -1) derivative at 100 K. The complex C 6 -1 crystallizes in the triclinic system and adopts the Pbca space group. The iron(II) ion is in a distorted octahedral environment shaped by three imine and three pyridine nitrogen atoms of the C n -tameMe ligand. The average Fe-N im and Fe-N py bo…