Sensing of Sulfur Dioxide by Base Metal Thiolates:Structures and Properties of Molecular NiN_2S_2/S0_2 Adducts

摘要

The cis-dithiolate N_2S_2Ni complex bismercaptoethanediazacycloheptanenickel(ll),(bme-dach)Ni or Ni-1',takes up two equivalents of sulfur dioxide in which thiolate-sulfur to S02-sulfur interactions are well-defined by X-ray crystallography.Ni-1'(center dot)2S0_2,C_9H_18N_2Ni0_4S_4,yields monoclinic crystals belonging to the P2(1)/c space group:a=10.308(4)A,b=13.334(5)A,c=10.842(4)A,a=90deg,beta=91.963(6)deg,y=90deg,and Z=4.Further characterization by v(SO)IR spectroscopy,thermal gravimetric analysis,electronic spectroscopy,and visual color changes upon reversible S0_2 adduct formation establish Ni-1' and the analogous bismercaptoethanediazacyclooctane derivative,(bme-daco)Ni,Ni-1,to be viable candidates for technical development as chemical sensors of this noxious gas.Visual S0_2 detection limits of Ni-1 and Ni-1' are established at 25 and 100 ppm,respectively.Both the Ni-1'(center dot)2S0_2 adduct and the Ni-1' reactant are air stable.In addition,the stability of Ni-1'(center dot)S0_2 to vacuum and removal of S0_2 by heating make Ni-1' a possible storage/controlled release complex for S0_2 gas.