Spectroscopy and electrochemical properties of a homologous series of acetylacetonato and hexafluoroacetylacetonato cyclopalladated and cycloplatinated complexes

A photophysical, electrochemical and computational study has been performed on a homologous series of cyclometallated Pd(ii) () and Pt(ii) () complexes of general formula [(C,N)M(O,O)]; (H(C,N) = azobenzene, 2-phenylpyridine, benzo[h]quinoline; M = Pd, Pt; H(O,O) = acetylacetone, hexafluoroacetylacetone). Experimental and computational data have shown the strong influence exerted by electronegativity of the ancillary ligand on the frontier orbitals of the complexes, such an effect being enhanced for the Pt(ii) species.     

Adsorption of 2-methylbenzoic acid onto MCM-41 mesoporous material: kinetics and equilibrium studies

Ordered mesoporous molecular sieves are widely studied as alternative materials in areas where sorptive and catalytic applications are required. MCM-41 type mesoporous material was tested as sorbent of 2-methylbenzoic acid (MBA), an aromatic carboxylic acid selected as model molecule for adsorption studies on mesoporous silicas. Adsorption kinetic studies of MBA on MCM-41 type materials were carried out using ethanol solutions at different MBA concentrations. Experimental results followed Langmuir isotherm model showing large adsorption capacity (3.5?g/g). Two kinetic models, the pseudo first- and second-order, were selected to describe the adsorption process and to determine the best model fitting with the experimental data. Kinetic parameters for each kinetic equation were calculated and discussed. It was shown that the MBA adsorption process onto MCM-41 material could be described by the pseudo-second-order equation and that the MCM-41 performs as a suitable adsorbent material.     

SEM-EDS investigation on PM10 data collected in Central Italy: Principal Component Analysis and Hierarchical Cluster Analysis

Background

Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) were applied on PM10 particle data in order to: identify particle clusters that can be differentiated on the bases of their chemical composition and morphology, investigate the relationship among the chemical and morphological parameters and evaluate differences among the sampling sites. PM10 was collected in 3 different sites in central Italy characterized by different conditions: yard, urban and rural sites. The concentration of 20 chemical parameters (C, O, Na, Mg, Al, Si, P, Cd, Cl, K, Ca, Sn, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn) were determined by Scanning Electron Microscopy – Energy Dispersive X-ray Spectroscopy (SEM-EDS) and the particle images were processed by an image analysis software in order to measure: Area, Aspect Ratio, Roundness, Fractal Dimension, Box Width, Box Height and Perimeter.

Result

Results revealed the presence of different clusters of particles, differentiated on the bases of chemical composition and morphological parameters (aluminosilicates, calcium particles, biological particles, soot, cenosphere, sodium chloride, sulphates, metallic particles, iron spherical particles). Aluminosilicates and Calcium particles of rural and urban sites showed a similar nature due to a mainly natural origin, while those of the yard site showed a more heterogeneous composition mainly related to human activity. Biological particles and soot can be differentiated on the bases of the higher loads of Fractal Dimension, which characterizes soot, and content of Na, Mg, Ca, Cl and K which characterize the biological ones. The soot of the urban site showed higher loadings of Roundness and Fractal Dimension than the soot belonging to the yard and rural sites, this was due to the different life time of the particles. The metal particles, characterized mainly by the higher loading of iron, were present in two morphological forms: spherical and angular particles. The first were generated by a fusion process at high temperature, while the second one had crustal origin (those characterized by typical terrigenous elements) and also human origin.

Conclusion

In this work a protocol for the morphological-chemical characterization of single particles has been developed. SEM analysis allows to classify particles in 10 different families and PCA and HCA have provided information about the sources of PM and similarities and differences among the sites.

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Maximum-likelihood estimation of Mueller matrices

We show that the method of maximum-likelihood estimation, recently introduced in the context of quantum process tomography, can be applied to the determination of Mueller matrices characterizing the polarization properties of classical optical systems. Contrary to linear reconstruction algorithms, the proposed method yields physically acceptable Mueller matrices even in the presence of uncontrolled experimental errors. We illustrate our method with the case of an unphysical measured Mueller matrix taken from the literature.     

Efficient synthesis of 9H-pyrrolo[1,2-a]indol-9-one derivatives based on active manganese dioxide promoted intramolecular cyclization

A series of 9H-pyrrolo[1,2-a]indol-9-ones have been prepared via in-situ sequential oxidation of [2-(1H-pyrrol-1-yl)phenyl]methanols promoted by active manganese dioxide. The procedure led to title compounds in good yields under mild conditions, without the need to isolate the intermediate aldehydes.     

UV/Vis to NIR Photoconduction in Cyclopalladated Complexes

Funky discotics : Photoconductivity is measured in newly synthesized cyclopalladated metallomesogens exhibiting hexagonal columnar mesophases at room temperature. The tuning of the HOMO/LUMO energy levels by modification of the chain/core linkage (ester 1 vs ether 2 ) makes compound 2 photoconductive across the whole UV/Vis/NIR range.