金属配合物表面诱导解离和有序银单原子层形成

A New Method of Ordered Silver Adlayer Formation by Surface-Induced Dissociation of Metal Coordination Complex

报道了乙腈介质中金属有机配合物[(dptap Ag)2](NO3)2(其中dptap为2 (2 吡啶亚氨基) 2H 1,2,4 噻二唑并[2,3 a]吡啶,2 (2 pyridylimino) 2H 1,2,4 thia diazolo[2,3 a]pyridine)在Au(111)表面诱导离解并形成有序银原子层的研究.STM结果显示,经在上述配合物的乙腈溶液中浸泡后,Au(111)表面形成(4×4)的吸附结构,此结构与Ag在Au(111)上较高欠电位下沉积所得到的结果类似.XPS结果证实所形成的吸附层中仅含有银原子.进一步用电动势法测定了[(dptap Ag)2](NO3)2的解离常数,并推测有序银原子层系与金表面相互作用从而诱导配合物的离解及Ag+的还原而形成.量子化学的计算结果与上述实验事实相符.这一表面诱导解离有望拓展至其他合适的有机金属配合物体系,从而发展为一种溶液法制备有序金属吸附层的通用方法.

A new method of ordered Ag adlayer formation by surface-limited adsorption and dissociation of a silver coordinated complex precursor [(dptap-Ag)_2](NO_3)_2 on Au(111) is reported, where dptap denotes dipyridyltetraazathiapentalen. STM results show an (4×4) adlayer structure on Au(111) surface, which resembles that of the Ag UPD adlayer at high underpotential shifts. XPS study confirms that the adlayer contains only silver atoms, whereas the electromotive force measurement indicates large stability constant of [(dptap-Ag)_2](NO_3)_2. Together with the computational calculation, it is concluded that the silver complex dissociation occurs dominantly upon adsorption onto surface process, leading to the formation of the ordered Ag adlayer. It is expected this surface-limited adsorption and dissociation may also work with other systems and develop into a general approach for preparation of metal adlayers.