Table 3.

¹HNMR spectroscopic data of the ligands (δ/ppm).

	2 CH3 groups of azoform (d, 3H)	2 CH3 groups of hydrazoform (d, 3H)	2 CH groups of azoform (d, 2H)	NH groups of hydrazoform (D2O exchangeable, s, 1H)	Aromatic + methylenic protons (m)
L1	1.588	2.50	3.41	broad	7.12–7.50
L2	1.61	2.50	3.36	broad	6.85–7.75
L3	1.60	2.495	3.39	broad	6.70–7.60
L4	2.00	2.44	3.52	broad	6.71–7.54
L5	2.24	2.49	3.85	broad	6.56–7.63
L6	1.37	2.50	4.00	4.80, 7.77	6.91–7.25
L7	1.436	2.50	3.34	4.83, 7.98	6.83–7.68
L8	1.45	2.50	3.34	4.79, 8.21	7.06–7.77
L9	—	—	3.45	—	6.42–7.97
L10	—	—	3.40	—	6.62–7.95
L11	—	—	3.50	—	6.50–7.12
L12	—	—	3.38	—	7.39–8.23