All chemicals were obtained from Sigma-Aldrich (Merck) and used as such. Silica gel 60 (0.04-0.063 mm particle size; 230-400 mesh, Sigma) was used for column chromatography. UV-vis spectra were recorded on an HP 8454 spectrophotometer at room temperature. High-resolution electrospray ionization (ESI) mass spectra were recorded on an Orbitrap Exploris 120 (Figures and). H NMR spectra were recorded on a Bruker Avance III HD 400 MHz spectrometer.