Synthesis Of Novel Triazene Reagents And Study On Their Color Reactions With Cd(Ⅱ),Hg(Ⅱ),Ni(Ⅱ),Co(Ⅱ)

Cadmium and Mercury are important heavy metal pollutants,whereas Cobalt and Nickel are essential trace elements for human body. Therefore ,studies on novel reagents and color reactions as well as thereby establishing new methods for the determination of these metal ions listed are very important in the fields of life science and enviromental monitor.Triazene reagents have been widely employed in spectrophotometric determination of some metals,such as Cadmium,Mercury and Nickel. In order to further probe their spectroscopic qualities and find more sensitive reation systems,five novel reagents were designed and synthesized in this paper ,i.e. ,1-(5,7-dibromo-8-quinolyl)-3-azo -benzene-triazene (abbreviated as DBQABT),1-azobenzene-3-(5,7-dibromo-8-quinolyl)-triazene(ABDBQT),1 -azobenzene-3-(6-methoxy-2-benzothiazolyl)-triazene (ABMBTT),1-(2-benzothiazolyl)-3-(5,7-dibromo-8-quinolyl)-triazene (BTDBQT) and 1-(6-methoxy-2-benzothiazolyl)-3-(5,7-dibromo-8-quinolyl)-triazene (MBTDBQT). These new reagents were mainly prepared from 8-aminoquinoline ,4-aminoazobenzene 6-methoxy-2-amino-benzothiazole through diazotizations and couple reactions under lower temperature. And they were all recrystallized from etnanol or the blending solvent of ethanol and distilled water,which compositions and structures were all charaterized by element analysis,IR and a special reagent by 1H-NMR.In this paper,these new reagentsolor reactions with Cd( II),Hg( II),Ni( II) and Co(II) have been studied in detail.The experimental results follow below:(1) In the presence of Triton X-100 DBQABT reacts with Cd(II) or Hg(II)to form a red complex with a molar ratio of 2 :1 in a borax buffer solution. The molar absorptivity of Cd-R and Hg-R is 2.01 105L.mol-1.cm-1 at 525 nm and 1.70 105L.mol-1.cm-1 at 520 nm,respectively. Beer's law are obeyed in the range of 0-20ug/25mL for them. (2) In a borax buffer solution ABDBQT reacts with Cd(II) and Hg(II) to form a red complex witha molar ratio of 2 :1 in the presence of Triton X-100 and OP,respectively. The molar absorptivity of Cd-R and Hg-R is 1.76 105L.mol-1.cm-1 at 524 nm and 1.53 105L.mor1.cm-1 at 517 nm,respectively. Beer's law is obeyed in the range of 0-10ug/25mL and 0-20ug/25mL for Cd-R and Hg-R,respectively. (3) In th presence of Triton X-100,ABMBTT reacts with Cd(II),Hg(II)and Ni(II) to form orange-red complexes The molar absorptivity of Cd-R ,Hg-R and Ni-R is 1.77 105L.mol-1.cm-1 at 518 nm ,1.40 105L.mol-1.cm-1 at 520nm and 1.84 x 105L.mol-1.cm-1 at 542nm. Beer's law are obeyed in the range of 0-10ug/25mL,0-20ug/25mL and 0-6ug/25mL for them. (4) BTDBQT reacts with Co(II) to form a stable blue-violet complex (1:1) in the presence of CTMAB and at pH 10.2. The apparent molar absorptivity is 1.05 x 105L.mol-1.cm-1 at 646 nm. Beer's law is obeyed in the range of 0 - 6ug/25mL.(5) In a weakly alkline medium MBTDBQT reacts with Co(II) and Ni(II) to form a blue-violet complex,respectively.The molar absorptivity of Co-R and Ni-R is 1.10 X105L.mol-1.cm-1 at 646 nm and 1.33x105L.mol-1.cm-1 at 623nm,respectively. Beer's law is obeyed in the range of 0 - 12ug/25mL and 0 - 5ug/25mL for them,respectively.A conclusion can be gotten from these data that these novel reagents exhibit highly sensitive color reactions with these metals listed with better selectivity. Among them,BQABT is one of the most sensitive reagents for the determination of Cd( II ) and Hg( II ). And ABMBTT is one of the most sensitive reagents for Ni(II). On the basis of these works,some methods determinating trace elements can be established with widespread application prospects in the fields of evironmental protection.meterial and life science.In our laboratory,5-(4-fomylphenylazo)-8-aminoquinoline (FPAQ) as an intermediate was discovered to show highly sensitive color reaction with Ni(II) or Co (II),which is also a highly sensitive reagent for the determination of Ni(II) or Co(II). One kind of new method can be thereby developed to determine trace amounts of Ni(II) or Co(II).