| Compounds | λmax nm (cm−1) | ||||
| π-π*, C=S | n-π*, C=S | d-d transition | |||
| (I) | 256, (39060) | 314, (31850) | ------ | ------ | ------ |
| (Ia) | 260, (38460) | 313, (31950) | 494, (20240) | 559, (17889) | 578, (17300) |
| (Ib) | 268, (37300) | 310, (32260) | 486, (20600) | 540, (18520) | ------ |
| (Ic) | 265, (37740) | 317, (31550) | ------ | ------ | ------ |
| (Id) | 266, (37600) | 324, (30860) | ------ | ------ | ------ |
| (II) | 287, (34840) | 344, (29070) | ------ | ------ | ----- |
| (IIa) | 288, (34720) | 342, (29240) | 462, (21650) | 485, (20620) | 522, (19160) |
| (IIb) | 308, (32470) | 358, (27930) | 466, (21460) | 493, (20280) | 524, (19080) |
| (IIc) | 284, (35210) | 344, (29070) | ------ | ------ | ----- |
| (IId) | 288, (34720) | 330, (30300) | ------ | ------ | ----- |
| (III) | 264, (37880) | 328, (30490) | ------ | ------ | ----- |
| (IIIa) | 296, (33780) | 356, (28090) | 540, (18520) | 600, (16670) | 622, (16080) |
| (IIIb) | 256, (39060) | 320, (31250) | 543, (18420) | 610, (16390) | ----- |
| (IIIc) | 280, (35710) | 332, (30120) | ----- | ----- | ----- |
| (IIId) | 260, (38460) | 304, (32890) | ----- | ----- | ----- |