4 nitrobenzenesulfonylchloride

Na₂CO₃ and HCl were obtained from Fluka, while 4-nitrobenzenesulfonylchloride and L- tryptophan were obtained from Sigma-Aldrich. Infrared spectra were recorded on a Bruker FT-IR spectrophotometer. The NMR data were recorded in methanol-d4 on a Bruker DPX-300 spectrometer with ¹H at 400 MHz and ¹³C at 400 MHz. Chemical shifts, δ, are given in ppm and referenced to tetramethylsilane (TMS). The mass spectrum was collected on a Bruker MicrOTOF spectrometer in the positive ion mode using pneumatically assisted electrospray ionization: capillary voltage, 2900 V; sample cone voltage, 15 V; extraction voltage, 1 V; source temperature, 80 °C; desolvation temperature, 160 °C; cone gas flow, 100 Lh⁻¹; desolvation gas flow, 100 L h⁻¹; collision voltage, 2 V; and MCP voltage, 2400 V.

All chemicals were purchased off the analytical grade. 4-bromomethylbenzenesulfonyl chloride, 1,3-diaminopropane, 4-nitrobenzene-sulfonyl chloride, and Et₃N from Sigma-Aldrich (USA). All solvents from Tedia (USA). Tris, FeCl₃, AlCl₃, and K₂CO₃ from Merck (Germany). Uranyl nitrate from BDH (England) and the uranium nitrate standard solution (1000 μg/mL U in 2%–5% aqueous HNO₃) from AccuStandard, (USA).
¹H-NMR and ¹³C-NMR were done on a 400 MHz Bruker instrument using DMSO as a solvent. The infrared spectra were recorded on a Tensor II FT-IR spectrometer with an ATR attachment from Bruker. UV-Vis spectra were recorded using a SPECORD 200 PLUS spectrophotometer, Analytik-Jena (Germany). Elemental analysis was performed using a FLASH 2000 CHNS/O Analyzer, Thermo-Scientific (USA). Thermal gravimetric analysis (TGA) was observed at a rate of 10 °C/min up to 900 °C under N₂ in alumina crucibles using a Netzsch TG 209F1 instrument. The sample mass range was 4.74–13.55 mg.