The structure of 1,1,3-trimethyl-Δ²- pyrazolinium perchlorate: An X-ray crystallographic and GIAO/DFT multinuclear NMR study

The crystal and molecular structure of 1,1,3-trimethyl-Δ²-pyrazolinium perchlorate has been determined and compared with those of other pyrazolinium salts (both 1,1 and 1,2-substituted). Reported ¹³C and ¹⁵N chemical shifts for a series of related pyrazolines have been compared with GIAO/DFT calculations, with excellent agreement. The combination of the biological properties of pyrazolines with those of the perchlorate anion in the same molecule will be discussed.