“…The FTIR spectrum of compound 2 (azine intermediate) displayed characteristic vibrational frequencies at 3492 (phenolic À OH), 2972 (ArÀ H), 2929 (CÀ H), 1628 (aldimine, C=N), and 1595 (CÀ C) cm À 1 due to intramolecular hydrogen bonding between phenolic À OH and aldimine function (Figure S7). However, after reaction with boron new vibrational frequencies appeared at 3413, 2852-2969, 1473, 1599, 1622, 1167, 826 and 1078 cm À 1 probably due to À OH (phenolic), C=C, CÀ H (Ar, alkyl), -CH=N (aldimine), BÀ O, BÀ F and BÀ N stretching vibrations, [82] respectively (Figure S8). Upon interaction with Cu 2 + frequencies due to OH/NH vibration bands at 3413 and between ~1250 to 1400 cm À 1 disappeared completely.…”