Selective mercury ion recognition using a methyl red (MR) based silatrane sensor†
A new methyl red (MR) based silatrane was synthesized in high yield by the transesterification reaction of methyl red-amidopropyltrimethoxysilane 1 (MR-APTMS) and trisisopropanolamine. Single crystal X-ray diffraction analysis was used to deduce the structure of silatrane 2 which was also supported by NMR (1H, 13C) spectroscopy, mass spectrometry, FTIR, UV-Vis and DFT studies. Silatrane 2 when surveyed for cation recognition ability with a library of metal ions in CH3CN/H2O (9 : 1, v/v) was found to act as an excellent UV-Vis probe for the selective recognition of Hg2+in vitro. Also, quantum mechanical calculations of the interaction complex [MR-APS-Hg]2+3 using DFT at the B3LYP level in conjunction with the LanL2DZ basis set determined the geometric and the stability parameters of the surveyed interaction.