Full Information Estimations of a System of Simultaneous Equations with Error Component Structure

In this paper we develop full information methods for estimating the parameters of a system of simultaneous equations with error component structure and establish relationships between the various structural estimator

Full Information Estimations of a System of Simultaneous Equations with Error Component Structure

In this paper we develop full information methods for estimating the parameters of a system of simultaneous equations with error component structure and establish relationships between the various structural estimators.

Optical, photoconducting, thermal and anisotropic mechanical behaviours of Benzimidazolium salicylate single crystals

Protonated organic single crystals of Benzimidazolium salicylate (BSL) were successfully grown by the slow evaporation solution technique at room temperature. The crystal structure and lattice parameters of the as-grown single crystal have been identified and calculated by the powder X-ray diffraction (PXRD) method. Microanalysis has confirmed the elemental compositions and the Fourier transform infrared (FTIR) spectroscopy technique has revealed vibrations of the functional groups in these crystals. The optical band gap was calculated indicating that the as-grown crystal exhibits 75% of optical transparency in the 350–800 nm range. Fluorescence study has suggested the blue emission nature of the crystal. The thermal stability of the as-grown crystal has been elaborated from the thermogrativity differential thermo-analysis (TG-DTA) technique. Vickers hardness measurement has revealed the mechanically soft nature of the crystal, which is driven by the reverse indentation size effect (RISE) and shows an anisotropic behaviour. A linear increase of the photocurrent on illumination suggests the positive photoconductivity of the crystal. The third-order non-linear optical property characteristics, such as the absorption coefficient (β), the refractive index (n2) and the susceptibility (χ(3)) have been examined using the Z-scan technique

Fluorescence Properties Reinforced by Proton Transfer in the Salt 2,6-Diaminopyridinium Dihydrogen Phosphate

Luminescent materials have many interesting applications, but it remains difficult to control the luminescence of organic materials and in particular to retain the same luminescence in solution and in the solid state, a property of interest for various imaging applications. In the present work, the fluorescent properties of the salt of 2,6-diaminopyridinium with dihydrogen phosphate have been explored. As a result of proton transfer from phosphoric acid to the pyridine nitrogen and the stabilizing effect of the two primary amines at the positions ortho to the pyridine nitrogen, the band gap between the HOMO and the LUMO is considerably diminished in comparison with that in 2,6-diaminopyridine. This is confirmed by a red shift in its absorption spectrum. Because protonation is retained in aqueous solution, the dissolved 2,6-diaminopyridinium dihydrogen phosphate salt retains a similar fluorescent spectrum as in the solid state. The crystals have been studied by single-crystal X-ray diffraction; FTIR, Raman, UV–vis–NIR, and luminescence spectroscopy; HOMO–LUMO calculations using DFT; and thermal analysis. The compound provides an example of a supramolecular motif that controls the crystal structure and the luminescence properties. In addition, the crystal exhibits negligible thermal expansion over a temperature interval of 150 °C. In short, 2,6-diaminopyridinium dihydrogen phosphate is an interesting compound for the design of luminescent devices