L' esplorazione floristica nel Sulcis (Sardegna sud-occidentale)

Here is show the account of floristic exploration in the Sulcis area. This study is based on existing bibliography and has been done through herbarium researches in the main national and international centres. The investigations allowed to take a census of all the works carried out in the Sulcis area, to verify the authors and the explored environment as well as the exsiccata stored in the various herbarium. From the analysis emerges that the coastal and the lagoon areas have been deeply studied since the second half of the XVIth century, the hill and the foot of the mountain areas since after the second world war, while the mountain areas and the rivers are nowadays still less known and sometimes totally unexplored. Is finally put in evidence which areas have a greater need to be researched both from floristic and vegetational point of view

Rigid-Core Oligothiophene-S,S-dioxides with High Photoluminescence Efficiencies Both in Solution and in the Solid State

The photoluminescence (PL) frequencies and quantum efficiencies of dithieno[3,2-b;2',3'-d]thiophene-4,4-dioxide (1), its 3,5-dimethyl derivative (2), and the corresponding 4-oxide (3) are reported and discussed in relation to their single-crystal X-ray structures. The peculiar packing modalities of dioxides 1 and 2, based on dimeric units originated by short S···O contacts between molecules related by an inversion center, cause an unusually high bathocromic shift of PL frequencies from solution to solid state. This effect is accompanied by a marked decrease in solid-state PL efficiencies (12% and 16%) compared to those in solution (75% and 77%). In monoxide 3 the loss of local symmetry inherent to the change SO2 → SO deeply modifies the self-assembly and PL properties, and the PL efficiency in the solid state is close to that in solution. Ab initio calculations on the ground and excited states of compound 1 were performed and compared to those of a conformationally mobile counterpart. Oligomers containing..

White emission from organic light emitting diodes based on energy down-convertion mechanisms

Balanced white electroluminescence (EL) emission from binary organic blends was achieved via intermolecular down-convertion processes: the exciplex and the Foerster transfer mechanisms. This was obtained by combining a low electronic affinity (EA) molecule, a diamine derivative (TPD), with two high electronic affinity substituted oligothiophenes having high and low ionization potential (IP), respectively. Both the energy down-convertion mechanisms were exploited in two single active-layer organic light emitting devices, showing stable white emission, independent of the applied voltage

Molecular Packing and Photoluminescence Efficiency in Odd-Membered Oligothiophene S,S-Dioxides

The single-crystal X-ray structures of three odd-membered thiophene oligomers bearing one central thienyl-S,S-dioxide moietytrimer, pentamer, and heptamerare reported. Absolute photoluminescence quantum yields in microcrystalline powders are given for all compounds. The solid-state photoluminescence efficiencies of the trimer (45%) and the pentamer (12%) were up to 1 order of magnitude higher than those generally measured in conventional oligothiophenes, while that of the heptamer amounted to only 2%. These results are accounted for in terms of molecular packing characteristics, which, owing to the competing effects of dipolar intermolecular interactions between the sulfonyl groups and intra- and intermolecular C−H···O hydrogen bondings and S···S interactions, change dramatically on changing the oligomer size. While the trimer is highly distorted and crystallizes in a chiral orthorhombic space group with the molecular long axes markedly tilted with respect to one another, the heptamer displays a coplanar ..

Train-the-trainer booklet bioeconomy and the UrBioFuture experience

Objective of this training is to bring your attention, as educators, to the importance of the bioindustry and the opportunities that it creates for the young people. In this booklet we will share with you tailored made educational and multimedia materials so you can use it in your classes and become the Ambassadors of UrBioFuture Experience

Thiophene-based oligomers with high photo- and electroluminescence efficiencies across the entire visible range

We present a new class of thiophene-based molecular materials with high solid-state photoluminescence efficiencies across the entire visible range. We show that full color tunability may be achieved, including white and purple, by binary blends of these materials, according to CIE standards. With some of these materials efficient electroluminescent devices were fabricated and characterized

Tuning Solid-State Photoluminescence Frequencies and Efficiencies of Oligomers Containing One Central Thiophene-S,S-dioxide Unit

We have synthesized thienylene- and phenylene-based oligomers displaying solid-state photoluminescence efficiencies up to 70% and photoluminescence frequencies which cover the entire visible range. All compounds contain one central nonaromatic thienyl-1,1-dioxide moiety in the main chain. The tuning of the light-emission frequency was achieved by progressively varying the degree of π−π electron delocalization between the nonaromatic moiety and the α-linked aromatic rings. All compounds displayed greater electron affinities than thienylene or phenylene oligomers of comparable lengths, as deduced from the reduction potentials measured by cyclic voltammetry

New light-emitting functionalized oligothiophenes

We present a new class of highly photo and electroluminescent oligomers based on the presence of one inner thienyl-S,S-dioxide unit as the luminophore. The light emission frequency of the new compounds, which are characterized by greater electron affinities than the corresponding oligomers bearing an unmodified thienyl ring, was tuned over the entire visible range by changing the nature of the alkyl or aryl groups attached in the α- and/or in the β-positions of the thienyl-S,S-dioxide moiety. A few aspects of the solid state supramolecular organization of the new compounds are reported

Chemically and thermally stable photo- and electroluminescent thiophene-based materials

We present a new class of thiophene-based oligomers and polymers with widely tunable photo and electroluminescence properties and which offer great potential for many different areas of application. We were able to synthesize materials displaying high solid-state fluorescence efficiency across the entire visible range. Electroactive polymers emitting light in the near IR were obtained by chemical and/or electrochemical polymerization of oligomers of different length. The polymers also displayed electrochromism, i.e. color change when electric current flowed through the material. All compounds were characterized by great thermo and photooxidative stability. With some of these materials efficient electroluminescent devices were fabricated and characterized