• Adongo, J.O.; Neubert, T.J.; Sun, G.; Janietz, S.; Lauermann, I.; Rademann, K.; Rappich, J.: Fabrication and Characterization of Surfaces Modified with Carboxymethylthio Ligands for Chelate-Assisted Trapping of Copper. ACS Applied Materials & Interfaces 9 (2017), p. 24273-24281

10.1021/acsami.7b05131

Abstract:
The metal ion chelating property was conferred onto silicon (Si) and gold (Au) surfaces by direct electrografting of the 4-[(carboxymethyl)thio]benzenediazonium cation (4-CMTBD). Infrared spectroscopic ellipsometry showed the presence of characteristic phenyl and carbonyl vibrational bands on the functionalized surfaces as a proof of existence of surface-bound organic units of 4-[(carboxymethyl)thio]benzene, (4-CMTB). The loss of diazonium group upon electrografting of 4-CMTBD was investigated using IR spectroscopy. A Faradaic efficiency of about 18.8−20.0% was realized in mass deposition experiments for grafting 4-CMTB on the Au surface using an electrochemical quartz crystal microbalance technique. Raman spectroscopy performed on the Si−(4-CMTB) surface after treatment with copper (Cu) ion solution provided evidence of metal ion chelation based on an observed v(Cu−O) peak at about 487 cm−1 and a v(Cu−S) signal at about 267 cm−1. The binding of Cu ions by the chelating ligands also caused a red shift of about 10 cm−1 in the Raman spectrum of the Si−(4-MTB)−Cu surface within the spectral region, characteristic of the v(C−O) signal. X-ray photoelectron spectroscopy investigations showed indications of the Cu(II) ion species chelated by the surface-bound carboxymethylthio ligands. The functionalized surface, Si−(4-CMTB), constitutes an alternative metal ion chelating surface that may potentially be developed for applications in trace-level trapping of Cu ions.