Table 2.

Infrared spectral data of the ligands and their organotin(IV) complexes.

	ν/cm−1
compound	ν(C=O)	ν(O–H)	ν(C=N)	ν(M–N)	ν(M–O)	ν(–N–SO2)
L1	1768 and 1725	3384	1618	—	—	—
1	1676	—	—	512	384	—
2	1650 and 1725	—	1617	516	417	—
L2	—	3423	1652	—	—	941
3	—	—	—	480 and 461	403	891
4	—	3423	1658	415	—	941