Search results for "Planarity testing"
showing 10 items of 28 documents
Exploiting multivalent nanoparticles for the supramolecular functionalization of graphene with a nonplanar recognition motif.
2013
The supramolecular modification of planar graphene with the geometri- cally mismatched, curved 9,10-di(1,3-dithiole-2-ylidene)-9,10-dihydroanthracene (exTTF) molecule is demonstrated. The exTTF-graphene interaction is governed by p-p and CH-p interactions, with a negligible contribution from charge transfer. We amplified these weak forces through multivalent gold nanoparticles. Our re- sults show that planarity is not a prerequisite for recognition motifs for graphene.
Solvent impact on the planarity and aromaticity of free and monohydrated zinc phthalocyanine: a theoretical study
2017
A theoretical investigation on the planarity of molecular structure of zinc phthalocyanine (ZnPc) and its aromaticity has been performed using B3LYP and M06-2X density functionals combined with selected Pople-type basis sets. The effect of the applied calculation method on the optimized structure of ZnPc and ZnPc∙∙∙H2O, both in the gas phase and in the polar solvent, was analyzed. To quantify the aromaticity of the ZnPc and ZnPc∙∙∙H2O complexes, both the geometric and magnetic criteria, i.e., Harmonic Oscillator Model of Aromaticity (HOMA) index and the nucleus-independent chemical shift (NICS) values at the centers or 1 A above the centers of structural subunits, were calculated. The energ…
First Annelated Azaphosphole-Ferrocenes: Synthetic Pathways and Structures
2012
The first annelated bis- and mono-3H-1,3-azaphosphole ferrocene sandwich compounds have been synthesized from aminoferrocenes, and their X-ray structures are compared to those of their selenide-protected P═Se analogues, showing net discrepancies both in metallocene backbone conformation and in fused-ring planarity.
cis-Bis(2-sulfidopyridine N-oxide)platinum(II).
2007
In the crystal structure of the title complex, [Pt(C5H4NOS)2], the Pt atom is coordinated by two O atoms and two S atoms in a cis configuration, forming a distorted square-planar coordination geometry. The molecule exhibits pseudo-C2v symmetry and is essentially planar, with a maximum deviation from planarity of 0.0124 (2) Å. The dihedral angle between the two pyridine rings is 5.85 (2)°.
3,5-diphenyl-1,2,4-triazin-6(1H)-one: synthesis, and X-ray and DFT-calculated structures.
2012
The title compound, C15H11N3O, (I), was obtained by the air oxidation of 3,5-diphenyl-4,5-dihydro-1,2,4-triazin-6(1H)-one. In the crystal structure, (I) forms centrosymmetric hydrogen-bonded dimers through pairs of N—H...N hydrogen bonds. The molecular structure of (I) deviates somewhat from planarity in the crystalline state, whereas a density functional theory (DFT) study predicts a completely planar conformation (Cspoint-group symmetry) for the isolated molecule. The solid-state conformation of (I) is stabilized by intramolecular hydrogen bonds,viz.one C—H...O interaction, which forms a six-membered ring, and three C—H...N interactions that each form five-membered rings. To estimate the …
Tuning the electronic properties and the planarity degree in the π-extended TTF series: the prominent role of heteroatoms
2018
The main asset of small molecules for application in organic electronics lies in the tunability of their electronic properties owing to the precise control of their molecular design. Semiconducting properties in organic compounds are for instance closely linked to the molecular planarity degree, including when considering various redox states. Among those species, the π-extended TTF (exTTF: 9,10-bis(1,3-dithiol-2-ylidene)-9,10-dihydroanthracene) presents fascinating redox and structural properties, which have been extensively studied in various fields of organic electronics. Here we show that S-exTTF, a sulfur enriched π-isoelectronic dithieno analogue of pristine exTTF, synthesized through…
Concentration depending fluorescence of 8-(di-(2-picolyl)) aminoBODIPY in solution
2014
[EN] An 8-dipicolylBODIPY derivative has been prepared and its photophysical properties evaluated under different conditions. Two different structures, hemicyanine and cyanine, are observed (depending on the solvent or the solution concentration). The hemicyanine form is not emissive whereas the cyanine form is fluorescent. This behavior is related with the planarity degree of the BODIPY core. The X-ray structure of the compound is reported and it shows that in solid state the hemicyanine form is present. The hemicyanine form seems to be stabilized by aggregation and is the main compound in concentrated solutions whereas the cyanine form is present in diluted solutions that are photochemica…
Computational modeling of single-versus double-anchoring modes in di-branched organic sensitizers on TiO2 surfaces: structural and electronic propert…
2014
We present a first-principles DFT investigation of the adsorption geometry on the anatase (101) surface of a prototypical di-branched organic dye based on the extended tetrathiafulvalene moiety, incorporating two anchoring cyanoacrylic acid units. Reduced model systems with one and two anchoring groups have been initially studied to investigate the vibrational frequencies related to TiO2 dye adsorption. Our calculations confirm that the reduced systems can be used as reliable models to study the anchoring modes and that the conclusions extracted from the reduced systems can be extrapolated to the entire molecule. A series of molecular structures have been investigated to simulate the anchor…
Symmetry-induced long-lived excited state inAu6−
2007
We present time-resolved photoelectron spectra in combination with quantum chemical calculations based on time-dependent density functional theory for the study of the long-lived excited state of ${\mathrm{Au}}_{6}^{\ensuremath{-}}$. The experimental spectra indicate an excited state lifetime of at least $90\phantom{\rule{0.3em}{0ex}}\mathrm{ns}$. It is shown that the orbital symmetry of the photoexcited state as well as the planarity of ${\mathrm{Au}}_{6}^{\ensuremath{-}}$ are responsible for the unusual long lifetime. A possible decay mechanism is the fluorescence of a photon which is estimated to take place on a time scale of $730\phantom{\rule{0.3em}{0ex}}\mathrm{ns}$.
Density-functional based tight-binding study of small gold clusters
2006
In this paper, we report the ability of self-consistent-charge density-functional based tight-binding method to describe small gold clusters. We concentrate our investigations mainly on anions, and find that the method describes their geometric and electronic structures fairly well, in comparison with density-functional calculations. In particular, the method correctly reproduces the planarity of ground-state structures up to cluster sizes in agreement with experiment and density-functional theory.