Capture of Fullerenes in Cages and Rings by Forming Metal-π Bond Arene Interactions

Nowadays, the task of the selectively capture of fullerene molecules from soot is the subject of several studies. The low solubility of fullerenes represents a drawback when the goal is to purify them and to carry out chemical procedures where they participate. There are different molecules that can act as a kind of cocoon, giving shelter to the fullerene cages in such a way that they can be included in a solution or can be extracted from a mix. In this work, a theoretical study of some known and new proposed organic molecules of this kind is presented. In all cases, the interaction occurs with the help of a metallic atom or ion which plays the role of a bridge, providing a place for a metallocene like interaction to occur. The thermodynamic arguments favoring the formation of this adduct species are addressed as well as the nature of the bond by means QTAIM parameters and frontier molecular orbitals analysis.

Electronic and magnetic properties of phosphorene tuned by Cl and metallic atom co-doping

We studied the electronic and magnetic properties of Cl and transition metal co-doped phosphorene. Different species and doping sites gave various characteristics. Biaxial strain was used to adjust the impurity states for V–Cl and Co–Cl co-doping.

Tunable electronic structures of germanium monochalcogenide nanosheets via light non-metallic atom functionalization: a first-principles study

The binary analogues of phosphorene, GeS and GeSe nanosheets, exhibit versatile electronic and magnetic properties through light atom functionalization.

DFT study of Rh-decorated pristine, B-doped and vacancy defected graphene for hydrogen adsorption

Rh adatom stability on graphene, with and without defects has been investigated by density functional theory (DFT). The feasibility to achieve uniform dispersion for the metallic atom and the hydrogen storage capacity for each system were evaluated.

Thermal expansion in isomorphic Me5Si3(Me=transition metal) compounds

Transition metal silicides have been investigated due to the applications in several fields, such as: structural materials, electronic devices, nuclear industry. The physical properties including mechanic, electric, magnetic, thermal, optical, etc. of these compounds are strongly dependent of the metallic atoms and their atomic bonds. The family of silicon-based compounds of Me5Si3stoichiometry, known as Nowotny phases, where Me is a IV, V or IV transition metal element crystallize in three different structures: 1) Ti5Si3, Zr5Si3and Hf5Si3compounds crystallize in a hexagonal structure obeying P6/mcm symmetry and (Me: 4d and 6g, Si: 6g) Wyckoff positions; 2) Compounds such as V5Si3, Cr5Si3, Mo5Si3, W5Si3, βNb5Si3and βTa5Si3crystallize in so-called T1structure with I4/mcm space group and (Me: 4b and 16k, Si: 4a and 8h) Wyckoff positions and 3) Compounds such as αNb5Si3and αTa5Si3crystallize also in a tetragonal structure, called T2, in same I4/mcm space group but different Wyckoff positions (Me: 4c and 16l, Si: 4a and 8h). The measurement of the thermal expansion coefficients of these compounds by high temperature X-ray diffraction shown that they are strongly dependent of the metallic atoms. Since these compounds crystallize in hexagonal or tetragonal symmetry, the thermal expansion is anistropic. The anisotropy of the thermal expansion in these materials have been controlled by the following ways: 1) by partial substitution of the metallic atom by another metallic atom to promote the formation of solid solutions, or 2) by formation of ternary compounds, by partial substitution of silicon by boron in the structures, for example. Since these compounds present high melting temperatures, they are prepared in polycristalline form by arc-melting process followed by heat-treatment at temperatures above 1400 K. The thermal expansion coefficients of Me5Si3compounds have been analyzed taking into account the crystal structure of these compounds.