Table 1. Photophysical properties of 8–10 in various solvents with decreasing polarity from aqueous (HEPES buffer) to toluene.
| λabs/nm | λem/nm | /cm−1 | |||||||
| Solvent | 8 | 9 | 10 | 8 | 9 | 10 | 8 | 9 | 10 |
| HEPES | 415 | 417 | 414 | 558 | 545 | 555 | 6175 | 5632 | 6137 |
| MeOH | 415 | 7 | 415 | 542 | 538 | 542 | 5646 | 5393 | 5646 |
| EtOH | 413 | 415 | 412 | 540 | 536 | 539 | 5695 | 5440 | 5719 |
| n-PrOH | 413 | 413 | 412 | 537 | 534 | 536 | 5591 | 5486 | 5615 |
| n-BuOH | 413 | 411 | 411 | 536 | 534 | 534 | 5556 | 5604 | 5604 |
| DMSO | 415 | 416 | 413 | 540 | 536 | 540 | 5578 | 5382 | 5695 |
| MeCN | 411 | 412 | 409 | 539 | 537 | 538 | 5778 | 5650 | 5863 |
| DMF | 410 | 412 | 409 | 538 | 535 | 537 | 5803 | 5580 | 5828 |
| Acetone | 406 | 409 | 405 | 531 | 530 | 530 | 5798 | 5582 | 5823 |
| EtOAc | 401 | 404 | 398 | 518 | 520 | 515 | 5633 | 5522 | 5708 |
| THF | 403 | 406 | 401 | 517 | 518 | 514 | 5472 | 5326 | 5482 |
| DCM | 418 | 421 | 415 | 523 | 524 | 521 | 4803 | 4669 | 4903 |
| CHCl3 | 418 | 418 | 415 | 513 | 516 | 512 | 4430 | 4544 | 4565 |
| Toluene | 404 | 406 | 402 | 500 | 507 | 499 | 4752 | 4907 | 4836 |
λabs: wavelength of maximum UV-Vis absorbance; λem: wavelength of maximum emission intensity; : Stokes shift.