Preparation And Characterization Of Sehiff Base Macrocycles

The research on macrocyclic ligands and their complexes have just been carried out for over thirty years, but it develops quickly for the reason that the structures of macrocycles are similar with those of some important bioenzymes in body, which are hopeful to acquire great breakthrough in biomimetic chemistry, environmental protection, new materials and exploitation of new medicines. Now the study of macrocycles has become an independent part which is as important as noncycles and is an indispensable branch in coordination chemistry of modern times. Especially Schiffbase macrocycles, they have a better research prospect in study and practice for their complexes are in possession of catalytic activity on imitating enzymes and are characterized by superior thermodynamics stability as well as dynamics inertia. Among them tetraazote Schiffbase macrocyclic complexes have brought a wealth of interest to researchers. The reasons for it lie in two aspects: firstly, the structures of tetraazote Schiffbase macrocyclic ligands are alike with that of natural porphyrin rings and have strong binding ability with small molecules such as O2, CO, CO2, so they can carry out biology imitation as model complexes thus have significant meaning on researching metal-protein and enzymes. Secondly, this kinds of complexes have potencial apply value as catalysts, extractants and conductors.The development of macrocyclic coordination chemistry has close relationship with the progress of synthesis methods. Now the way to prepare macrocyclic complexes includes non-template, high diluted methods and template methods. In this paper, we synthesize several macrocycles based on the ways mentioned above. The details are as follows:In the first part the development of Schiffbase macrocycles was reviewed. Someavailable synthesis methods were introduced and the meaning to resreach the macrocycles are emphasized. Meanwhile, we give some questions during synthesis.In the second part, macrocyclic precursors were synthesized. Because of high price of base material we synthesized it by ourselves with two metheds: syntheisze in liquid-phase and solid-phase at low-temperature, respectively. Therein the method of solid-phase at low-temperature is a new one: 2,6-diformyl-4-methylphenol was prepared via solvent-free oxidation reation at r.t from nanometer r-MnO2 and 2,6-glycol-4-methylphenol. Compared with liquidoid method, the reaction time of this method was cut to 5~6h, yield was improved by 6%, and had simpler operation, without pollution.The third part is synthesis of macrocycles. Firstly, we obtained tetraazote Schiffbase macrocyclic ligand BDBPH by high diluted method and it's structure was identified by IR,'H NMR and Elemental analysis; Secondly, a new Schiffbase macrocyclic ligand TDDPD was gained by non-template method., it's struture had been identified by X-ray diffraction study; At last, homodinuclear Cu(II) complexes with ligand TDDPD was synthesized by the method of solid-phase at low-temperature, and provide a new clew to the synthesis of these kinds of complexes.In the last part, 2,6-bis(benzimidazolyl)-4-methylphenol was synthesized from 2,6-diformyl-4-methylphenol and o-phenylendiamine by [1+2] condensation reaction at room temperature. It's structure was identified by IR,1H NMR, MS and Elemental analysis. This method is relative simple and purification is convenient.