Zinc oxid nano tubes have attracted much attention in recent years. Hardly, direct uses of zinc oxid nano tubes which modified by SiO 2 as a catalyst with recyclability has been applied for several organic reactions. The average particle size of ZnO catalysts is 57 nm, it has been characterized by XRD. Nano tubes surfaces have high density defects. The condensation of isatoic anhydride and an aromatic aldehyde exposed to ammonium acetate in the presence of few amounts of zinc oxide nano tubes modified by SiO 2 as a catalyst can be a simple, suitable and efficient method for the quinazolin derivatives synthesis, the positive aspect is recyclable ability of the catalyst. It is clear that some characterization of catalyst such as combination of the small particle size and high-density surface defects of zinc oxid nano tubes which modified by SiO 2 is the basic reason for unique catalytic activity of the catalyst. The practical and simple method led to unbeatable yields of the 2,3-Di hydro quinazolin-4(1H)-one derivatives at short times under mild conditions.
D-H 2 Pen-binding behavior to [VO(acac) 2 ] at pH = 7.00, 7.50 and 10.0 has been studied in thermodynamic viewpoint using UV/VIS spectroscopy. The optical absorption spectra of [VO(acac) 2 ] were analyzed in order to obtain binding constants and stoichiometries using SQUAD software. The estimation of binding constant at various temperatures enabled us to calculate all of the thermodynamic parameters of binding using the van't Hoff equation. Studies of described reactions at pH = 7.00, 7.50 and 10.0 show exothermic, endothermic and exothermic modality, respectively. D-penicillamine is a potentially tridentate ligand, but the pK a for the −COOH, NH 3 and S−H groups are 1.99-2.00, 8.0 and 10.6, respectively, as a result S−H can not release proton at pH = 7.00 and pH = 7.50, so the coordination of S is not possible except at strong alkali mediums. At pH = 7.00, D-H 2 Pen converts [VO(acac) 2 ] to a vanadyl Schiff base complex (coordination mode is N 2 O 2 ). At pH = 7.50, D-H 2 Pen is converted to HPen − and the exchange of acac − with HPen − produces VO(HPen) 2 . It is clear that the coordination is formed via amine nitrogen and carboxylate oxygen. At pH = 10.0, the main product is a vanadyl complex with the (S 2 O 2 ) coordination mode. Studies in different ionic strengths of KCl confirm these products according to the number of ions in each medium. The formation constants of the products of VO(acac) 2 with D-penicillamine at pH = 7.00 and 7.50 are independent of ionic strength, but a Debye-Huckel-type equation was established for the dependence of the formation constant on ionic strength at pH = 10.0.
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