Synthesis And Study On The Spectrum Properties Of Novel Compounds Containing Bromo-arylbenzothiazole Moiety

As one of the traditional analysis methods, chemiluminescence is applied widely at all times, and seeking a chemiluminesct reagent which is stable, high efficient and with excellent chemiluminescent properties has become one of the most prevalent research hotspots. Based on the further research about the relationship between structure and properties of organic compounds, a series of chemiluminesct reagents containing bromo-arylbenzothiazole moiety was synthesized. Pthalylimide as the raw material orderly reacted was subjected to nitration, reduction, mercaptization, and hydrazination reactions, respectively, for the synthesis 7-amino-6-sulfanylphthalazine-1,4(2H,3H)-dione(AMHP), the total yield of the AMHP synthesis increased from 20% to 28.2% by using the improving experimental method. And then, the chemiluminesct reagents containing bromo-arylbenzothiazole moiety such as 2-(4'- bromizationphenyl)phthalazino[6,7-d]thiazole-5,8(6H,7H)-dione, 2-(4'-hydroxyl-3',5'-dibro- mphenylphenyl)-phthalazino[6,7-d]thiazole-5,8(6H,7H)-dione, 2-(2'-hydroxyl- 3',5'-dibromph- enylphenyl)phthalazino[6,7-d]thiazole-5,8(6H,7H)-dione, 2-(4'-methoxyl-3',5'-dibrompheny- lphenyl)phthalazino[6,7-d]thiazole-5,8-(6H,7H)-dione, 2-(3',4', 5'-Tribromophenyl)phthalaz- ino[6,7-d]thiazole-5,8(6H,7H)-dione were synthesized by the condensation reactions between AMHP and bromo benzaldehydes, the yields were 40%-50%. Their structures were characterized by UV, IR and 1H-NMR.1×10-2mol/L K3Fe(CN)6 base solution as carrier liquid, the novel compound's chemiluminescent property was investigated by the chemilumoreader equipped under injected 1×10-7mol/L chemiluminesct reagent solution. The results exhibited that the reaction between each novel compound and K3Fe(CN)6 in base solution exploded strong chemiluminescence, and the compounds'chemiluminescent intensities were obviously better than that of conventional illuminant luminal, among these compounds, 2-(4'-hydroxyl-3',5'- dibro-mphenylphenyl)-phthalazino[6,7-d]thiazole-5,8(6H,7H)-dione was the best and its chemiluminescent intensity was 230 times more obvious than that of luminal, indicating the reagent can be widely applied in analytical chemistry. Compounds with more or stronger electron donor groups (eg. methoxy, hydroxyl, etc) had high chemiluminescent intensity. Different chemiluminescent intensities were due to different substitution positions, even if the substituents wew same. The fluorescence spectrum and chemiluminescence spectrum of each novel chemiluminescent compound were determined by fluorophotometer. The maximum emission wavelength shifted towards the longer wavelength because of the substituent's electron supplying capacity. The electron was easily excited to transit because the charge density of the conjugated system was increased by the electronic effect of the electron donor group. The import of bromine atom altered the charge density of benzothiazole, and the energy difference between excited state and ground state was debased, the excitation efficiency and the luminous efficiency were increased.The charge distribution and the optimized configuration of each novel chemiluminesct reagent were calculated by HyperChem Release 7.0 and Gaussian03W B03. The ground state energy of each compound was between -3412.096 cal/mol and -3879.8284 cal/mol, which indicated that the compounds had upstanding stability. The electronic effects of different substituents in different positions influenced the charge distribution of each atom, altering the fluorescence properties and the chemiluminescent characteristics of every reagent. The nitrogen in the hydrazine group had very high charge density, which activated this group in chemiluminesct reaction and induced the N-N bond was prone to rupture. The optimized configuration of each reagent was plane state. The configuration of hydrazide was plane because of the electronic delocalization of the n-πconjugation between the electron pair of nitrogen and carbonyl; the configuration of thiazole is plane because of the conjugation between the electron pair of sulphur and theπbond of benzene. Based on the datas of chemistry calculation, the mechanism of the chemiluminescence reaction of the novel compounds containing 2-bromo-arylbenzothiazole moiety was conjectured.