The aim of this review is to emphasize solvent free or green synthesis, a most efficient utilization of starting materials to give maximum yield, and an alternative route to producing novel promising materials. In this regard the phase diagram study has shown applications in the determination of the precise composition of binary compounds of a specific nature and in the identification of the parameters that affect the crystal growth. To provide an overview worthy of phase diagram, physicochemical, thermal and structure investigations; studies of eleven systems, namely, urea–m-nitrobenzoic acid, urea–p-nitrophenol, urea–resorcinol, benzoin–o-phenylenediamine, pyrene–m-dinitrobenzene, vanillin–p-anisidine, resorcinol–p-dimethylaminobenzaldehyde, benzophenone–diphenylamine, anthracene–picric acid, 8-hydroxyquinoline–salicylic acid and 8-hydroxyqunoline–1,2,3-trihydroxybenzene forming organic complexes, have been reported. In addition, the original data of a newly synthesized complex of m-hydroxybenzaldehyde (HB) and p-chloroaniline (CA) is being reported for the first time. The phase diagram of HB–CA system also shows the formation of a complex in 1:1 M ratio, and two eutectics on either side of the complex. The complex's formation was studied using FTIR, NMR, DSC and powder X-ray diffraction techniques. The thermodynamic parameters such as heat of mixing, entropy of fusion, roughness parameter, interfacial energy and excess thermodynamic functions were calculated using the heat of fusion values. The single crystal growth and the atomic packing studies of some of the complexes have confirmed the formation of complexes. The optical transmittance efficiency and transparency of novel HB–CA complex crystal were found to be 70% and 399 nm, respectively. 相似文献
The synthesis and physical properties of meta- and para-bis(metallocene) benzene complexes with M = Fe, Co, Ni are reported. The electrochemical properties suggest greater electronic interaction between metal centers in the para-M complexes. In addition, the magnetic properties suggest different degrees of spin exchange for the meta and para complexes, with the latter exhibiting more pronounced antiferromagnetic coupling. These molecular complexes are considered prototypes for extended metallocene polymers. 相似文献
In the present report, CuO, Cu2O and Cu have been successfully synthesized through a facile, one‐step hydrothermal method at a relative low temperature by controlling only the concentration of citric acid. Compared with other synthetic methods, the present method is mild, high‐efficient and nontoxic. The crystal structure and morphology of the as prepared samples were characterized by X‐ray diffraction and scanning electron microscopy, respectively. The mechanism for the crystal phase and morphological changes with different citric acid concentrations were discussed. The possible reaction process of the synthesis was also studied on the basis of the experimental results. We hope that this facile, one‐step hydrothermal method could be used in controlling synthesis of other metals and metal oxides under appropriate experimental conditions. 相似文献
The precipitation of barium, zinc, lead, copper and silver chromates was studied in the presence of the chelating organic anions gluconate, tartrate, citrate, aspartate, glutamate and E.D.T. Aate. Generally, these chelators complex the metal cation and reduce the free metal cation and mean metal chromate concentrations in solution. The rates of nucleation with microcrystallite formation were then markedly reduced and the induction periods increased from below 1 sec to well above 100,000 sec with increasing chelator/cation concentration ratio; the experimental results were expressed by the relations; The coefficients F at any metal chromate concentration were related in turn to the stability constants of the metal-chelator complexes. 相似文献
The corrosion properties of several borosilicate nuclear waste glasses exposed to aqueous environments have been investigated using a combination of Rutherford backscattering (RBS) depth profiling and solution analysis. Using the technique of RBS, the concentration of individual elements in the glass can be quantitatively profiled within a 1–2 μm surface layer. All of the glass surfaces were corroded in distilled water at 90°C for times ranging from 0–28 days. The evolution and composition of the altered layer that formed on the glass surface was of particular interest, since this layer can be crucial in determining whether or not the remainder of the glass undergoes further rapid corrosion. Within the altered surface layer produced by the corrosion process, there was an enhancement in the concentrations of U, Ti, Sr, Nd, Gd, and Ca and a depletion of Na, Si, Cs, (and probably B) relative to the concentrations present in the bulk glass. The U concentration, for example, was often 3–4 times greater in the altered surface layer than in the bulk. The layer apparently forms due to a local reaction that results in the formation of insoluble complexes on the glass surface. A simple model of the corrosion process has been used to identify the most likely insoluble metal complex for each metal present in excess in the alteration layer. The mechanical and chemical stability of this layer are also discussed. 相似文献
Abstract Four macrocyclic liquid crystalline ligands derived from 1,8 dihydroxy ethyl 1,3,6,8,10,13 hexa aza cyclotetradecane(DHAT) and trans-4-n-alkoxy cinnamoyl chloride have been synthesised and their metal complexes using Cu(II),Ni(II),Pb(II), V(V) and U(VI) metal ions have been isolated. The ligands and their metal complexes were characterised by elemental analysis, FTIR,NMR,X-Ray and DSC studies. Polarising microscope was used to identify mesomorphic textures of the ligands and the complexes. The transition temperature and mesophase textures of the ligands and complexes have been compared. The effect of presence of different metal ions on mesomorphic properties has been discussed. 相似文献
