Table 2.

Comparison of observed and calculated ¹H and¹³C chemical shifts (δ in ppm) for assignments of Salen compounds in gas phase using B3LYP/6-311G (d, p) level theory (Assignments refer to Scheme 1).

H2L1	B3LYP/6-311G (d, p) level	Experimental
s, 3H	1.15	1.31–1.34
H	5.02	4.04
m, 3H	6.56–7.92	6.77–7.03
m, 1H	8.50	8.53
m, 1H	13.41	13.90
s,2H	3.98	3.99
s,6H	0.68	0.98
RMSD	0.9031	-
13C NMR
CH3	24.80	15.2
O-CH2	74.65	64.2–67.0
Arom-C	109.82–152.78	116.3–147.6
C–OH	152.78	152.2
CH=N	160.47	167.3
C–(CH3)2	41.98	24.0
(CH3)2-C–(CH3)2	54.49	36.1
RMSD	3.2913
H2L2
s, 3H	3.48	3.75
m, 1H	6.81	7.06–7.17
m, 3H	8.30	8.48
m, H	12.94	13.91
s, 2H	3.47	3.94
s, 6H	2.65	2.48
RMSD	0.9110	-
13C NMR
O-CH3	54.82	54.94–56.46
Arom-C	113.50–151.43	117.23–150.18
C–OH	151.37	153.71
CH=N	159.58	165.77
C–(CH3)2	24.66	31.40
RMSD	3.3192	-