Rahane A.B.,RYK Science College |
Rahane A.B.,University of Pune |
Deshpande M.D.,RYK Science College
Journal of Physical Chemistry C | Year: 2012
The structural and electronic properties of the (Ga 2O 3) n clusters (n = 1-10) have been studied within the framework of density functional theory. The (Ga 2O 3) n clusters show the preference for 4-membered (Ga 2O 2) and 6-membered (Ga 3O 3) rings. For n = 4, the lowest energy configuration appears to be derived from the bulk corundum (α-Ga 2O 3) configuration. For larger clusters (n = 5-10), the structures evolve around the corundum fragment and are more symmetric with layered configuration. There are 3-, 4-, and 5-fold coordinated Ga atoms and 2-, 3-, and 4-fold coordinated oxygen atoms. The (Ga 2O 3) n structures have similarity to that of the α-Ga 2O 3 phase, and the average coordination of Ga and oxygen atoms in clusters are lower than the values in the α-Ga 2O 3. The ionization-induced distortions in the lowest-energy configuration of the respective neutral clusters are small. The isomers with cage configurations lie higher in energy compared with the layered lowest energy structures we have obtained. A sequential addition of a Ga 2O 3 unit to the (Ga 2O 3) n cluster initially increases the binding energy, though values of the HOMO-LUMO gap, ionization potential, and electron affinity do not show any systematic variation in these clusters. The bonding characteristics for these clusters is studied using Bader charge analysis and by the electron localization function. With the increase in cluster size, the charge transfer from Ga atoms to oxygen increases toward the value in bulk. The stability of the cluster is dominated by ionic Ga-O interactions with some covalent character between Ga-sp and O-p orbitals. © 2011 American Chemical Society.
Patil S.S.,RYK Science College |
Patil S.V.,RYK Science College |
Bobade V.D.,RYK Science College
Synlett | Year: 2011
Fe(acac)TBAOH-catalyzed three-component coupling-cycloisomerization reaction of aldehydes, terminal alkynes, and amines provides a diverse range of heterocyclic compounds such as aminoindolizines and quinoline derivatives. © Georg Thieme Verlag Stuttgart - New York.