Table 1.

Characteristic FT-IR vibrations of the axial ligand of compounds 2–7.

Compound	FT-IR Vibrations	Reference
2	ν(NO2) = 1474 cm−1 ν(N=O) = 1279 cm−1 ν(N–O) = 979 cm−1	[26]
3	ν(SCN) = 2036 cm−1	[24,27]
4	ν(COO) = 1525 cm−1	[28]
5	ν(C–H) = 3132, 3096, 3014, cm−1 ν(C–H) = 2926, 2852, 2786 cm−1	[4]
6	ν(C–H) = 3111, 3046, 3012 cm−1 ν(C–H) = 2949, 2918, 2865, 2838 cm−1	[4]
7	ν(Fe-O-Fe) = 749 cm−1	[23,24]