Coordination behavior of theophylline with Au(III) and electrochemical reduction of the complex. (1st May 2019)

• Record Type: Journal Article
• Authors: Jin, Lei; Liu, Cheng; Yang, Fang-Zu; Wu, De-Yin; Tian, Zhong-Qun
• Is Part Of: Electrochimica acta. Volume 304(2019)
• Page Start: 168
• Page End: 174
• Publication Date: 2019-05-01
• Subjects: Theophylline (THP) -- Coordination behavior -- DFT -- Electrode behavior -- Cyanide-free gold electrodeposition; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2019.02.118
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: Coordination behavior between theophylline (THP) molecule and Au(III) ion as well as electrochemical reduction of THP-Au(III) complexing ion were studied in detail. UV–vis absorption spectroscopy clarifies that Au(III) is coordinated with THP in a 1:2 M ratio. Raman spectroscopy indicates that it is N in THP chemically bonding to Au(III), and density functional theory (DFT) together with time-dependent density functional theory (TD-DFT) further reveal that the specific N atom is N9 in the imidazole ring (N7H form). Based on the invented formula of cyanide-free gold electroplating with THP as a complexant, the electrode behavior of THP-Au(III) ion on the gold electrode was studied. The results show that the stability constant K f of THP-Au(III) ion is 2.7 × 10 35, and the reduction of THP-Au(III) ion is in irreversible with diffusion control. Highlights: Theophylline (THP) is a novel complexant for cyanide-free gold electroplating. The coordination behavior between THP and Au(III) was determined. The stability constant of THP-Au(III) ion was obtained by voltammetric curve. The reduction of THP-Au(III) ion is in irreversible with diffusion control.