7. A water soluble pillar[5]arene macrocycle WP5 and its binding with an aminoglycoside antibiotic, amikacin, in water, was reported. The proposed structure of the host guest complex is shown below. HO HOI COM CO2 NH3 HOT HO HO HO *H3N. o, o NHE+ CO2 - CO2 _02C o coz CO2 , CO2 CO2 *H3N O COM CO2 coz WP5 CO2- e. Addition of acid (e.g. HCl) to the complex solution resulted in the formation of a white precipitate. 'H NMR analysis of the filtrate showed that resonance of amikacin shifts back to the original position. Explain. 2,6" e) H NH | d) ) c) b) a) 5 3 2 1 0 ppm H NMR spectrum (500 MHz, D20, 298K) of: (a) [WP5] = 4.0 mM; (b) [WP5] = 4.0 mM and [1] = 2.0 mM; (c) [WP5] = [1] = 4.0 mM; (d) [WP5] = 4.0 mM and [1] = 8.0 mm; (e) [1] = 4.0 mM solutions. Asterisks indicate residual solvent peaks (HDO and CH3OH)