non covalent interactions in anisole co2 n n 1 2 complexes

Non-covalent interactions are a ubiquitous binding motif and a challenge for theory and experiments

High resolution optothermal spectroscopy of pyridine in the S-1 state

The optothermal technique has been utilized to obtain the first high resolution spectrum of pyridine in the region of the S1←S0 electronic transition. Rotational profiles for several vibronic bands (000,6a10,16b206a10,6a20,1210) were measured and found to be severely homogeneously broadened with linewidths of the order of 3–5 GHz, in agreement with previous lifetime measurements. Rotational constants of pyridine in the excited S1 vibronic levels were extracted by a band contour analysis. The values obtained are in good agreement with results from ab initio calculations, also presented here

Nanostructured Photoelectrochemical Biosensing Platform for Cancer Biomarker Detection

The innovative photoelectrochemical properties of multifunctional nanomaterials are here investigated for the development of biosensing platforms for rapid and sensitive detection of a class of cancer biomarker candidates, known as microRNAs. Many different transducers have been proposed, so far, for microRNA detection. Recently, with the emergence of novel photoelectrochemically active species and new detection schemes, photoelectrochemistry has received increasing attention. Gold nanostructures have been, here, used to modify TiO2 electrodes. The surface of the nanostructured platform has been modified by nucleic acid capture probes (CPs). Biotinylated target miRNAs have been recognized by the specific CPs. The biosensing platform has been incubated with streptavidin alkaline phosphatase and exposed to a proper substrate. The product of the enzymatic reaction has been photoelectrochemically monitored. A compact and hand-held analytical device has been developed in order to have a final prototype in line with the concept of point of care testing. (C) 2017 The Authors. Published by Elsevier Ltd

Vibrational spectrum of 4-¯uoraniline

Abstract The Raman spectrum of 4-¯uoraniline (4FA) has been recorded, the quadratic force ®eld has been calculated at RHF/6-31 1 G p level of theory and then scaled to reproduce the experimental frequencies, by using Pulay's scaled quantum mechanical force ®eld (SQMFF) methodology. Likewise, DFT force ®eld has been calculated at the B3LYP/6-31 1 G p level. On the basis of all these results, a general assignment of the vibrational spectra of 4FA has been proposed and compared with that of aniline in order to determine the substitution effect of the¯uorine atom.

A Photochromic Azobenzene Peptidomimetic of a β-Turn Model Peptide Structure as a Conformational Switch

The insertion of azobenzene moiety in complex molecular protein or peptide systems can lead to molecular switches to be used to determine kinetics of folding/unfolding properties of secondary structures, such as α-helix, β-turn, or β-hairpin. In fact, in azobenzene, absorption of light induces a reversible trans ↔ cis isomerization, which in turns generates a strain or a structure relaxation in the chain that causes peptide folding/unfolding. In particular azobenzene may permit reversible conformational control of hairpin formation. In the present work a synthetic photochromic azobenzene amino acid derivative was incorporated as a turn element to modify the synthetic peptide [Pro7,Asn8,Thr10]CSF114 previously designed to fold as a type I β-turn structure in biomimetic HFA/water solution. In particular, the P-N-H fragment at positions 7–9, involved in a β-hairpin, was replaced by an azobenzene amino acid derivative (synthesized ad hoc) to investigate if the electronic properties of the novel peptidomimetic analog could induce variations in the isomerization process. The absorption spectra of the azopeptidomimetic analog of the type I β-turn structure and of the azobenzene amino acid as control were measured as a function of the irradiation time exciting into the respective first ππ* and nπ* transition bands. Isomerization of the azopeptidomimetic results strongly favored by exciting into the ππ* transition. Moreover, conformational changes induced by the cis↔ trans azopeptidomimetic switch were investigated by NMR in different solvents

Ascorbic acid-sensitized Au nanorods-functionalized nanostructured TiO2 transparent electrodes for photoelectrochemical genosensing

Au nanorods (NRs) modified nanostructured TiO2/ITO electrodes have been fabricated and characterized in order to develop a biosensing platform for the photoelectrochemical determination of microRNAs. The proposed method is based on the use of thiolated DNA capture-probes (CPs) immobilized onto Au NR surface. The Au NRs are chemically bound at the surface of TiO2/ITO electrodes by means of the mercaptosuccinic acid linker. Subsequently, the DNA CPs are bound to the Au NR surface through the thiolate group, and reacted with the target RNA sequence. Finally, the obtained biosensing platform is incubated with alkaline phosphatase and l-ascorbic acid 2-phosphate (AAP) enzymatic substrate, for the in situ generation of ascorbic acid (AA). Such AA molecule, coordinating to surface Ti atoms, generates a charge transfer complex, that results in a shift of the UV absorption threshold toward the visible spectral region of the nanostructured TiO2 forming the electrode and, hence, in the occurrence of an absorption band centered at 450\u202fnm. The photoelectrochemical monitoring of the formation of the AA-TiO2 complex, under the visible light of a commercial LED light source, allows the selective and quantitative detection of the target microRNA strands

Studio della dinamica di rilassamento vibrazionale ed elettronico in sistemi molecolari

Dottorato di ricerca in scienze chimiche. 9. ciclo. Relatore E. CastellucciConsiglio Nazionale delle Ricerche - Biblioteca Centrale - P.le Aldo Moro, 7, Rome; Biblioteca Nazionale Centrale - P.za Cavalleggeri, 1, Florence / CNR - Consiglio Nazionale delle RichercheSIGLEITItal