Abstract: A polynuclear complex was synthesized by the reaction of CoCl2 with 2,2’-bipyridine-1,1’-dioxide in DMF solution. Elemental analysis, IR, UV and molar conductivity measurements indicated the composition of the complex corresponding to the formula [Co3(bipyO2)4Cl4]Cl2.Study of the properties showed that the complex has good sensitivity and selectivity for ammonia. The output voltage of sensor produced by the complex responses non-linearly to the change of ammonia concentration in the range of 3.0×10－5～1.2×10－4 mol•L－1,but linear response was found in the range of 1.4×10－4～1.3×10－3 mol•L－1.The sensor manufactured by the complex could be used to detect and control the concentration of NH3 in production.

Key words: Synthesis, Sensor, Cobalt chloride, Polynuclear complex, 2,2’-bipyridine-1,1’-dioxide