Table 3.
Geometric and electronic parameters of sulfonamides, mono- and diiodosulfonamides RSO2X, X = NH2–nIn (MP2/DGDZVP//B3LYP/D GDZVP). HOMO (highest occupied molecular orbital), LUMO (lowest unoccupied molecular orbital), CM5 (charge model 5), NBO (natural bond order), LP (lone pair).
| Parameter | R = CH3 | R = CF3 | R = p-Tol | R = p-NO2C6H4 | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| X= NH2 | NHI | NI2 | NH2 | NHI | NI2 | NH2 | NHI | NI2 | NH2 | NHI | NI2 | |
| S–N, Å | 1.678 | 1.707 | 1.745 | 1.646 | 1.659 | 1.679 | 1.683 | 1.717 | 1.761 | 1.673 | 1.702 | 1.740 |
| N–I, Å | – | 2.115 | 2.136 | – | 2.103 | 2.121 | – | 2.116 | 2.139 | – | 2.111 | 2.134 |
| ∠SNI(H)I(H) | 126.5 | 126.6 | 137.0 | 135.1 | 141.0 | 155.3 | 124.9 | 123.7 | 135.5 | 127.7 | 127.4 | 138.6 |
| ΣN | 335.5 | 337.3 | 344.9 | 343.3 | 348.6 | 355.2 | 333.8 | 334.6 | 343.7 | 336.6 | 338.1 | 346.0 |
| HOMO, eV | −12.720 | −10.480 | −10.242 | −13.453 | −10.685 | −10.382 | −9.734 | −9.835 | −9.881 | −10.375 | −10.349 | −10.289 |
| LUMO, eV | 5.141 | 0.644 | −0.475 | 4.946 | 0.317 | −0.735 | 2.161 | 0.694 | −0.435 | 0.197 | 0.116 | −0.545 |
| LUMO–HOMO gap, eV | 17.861 | 11.124 | 9.767 | 18.398 | 11.001 | 9.647 | 11.895 | 10.529 | 9.449 | 10.571 | 10.466 | 9.744 |
| CM5 charge on N | −0.600 | −0.503 | −0.412 | −0.574 | −0.501 | −0.428 | −0.601 | −0.502 | −0.407 | −0.593 | −0.501 | −0.412 |
| CM5 charge on I | – | 0.223 | 0.223 | – | 0.279 | 0.272 | – | 0.208 | 0.212 | – | 0.230 | 0.232 |
| Electrophilicity (I) | – | 1.866 | 1.600 | – | 2.168 | 1.820 | – | 1.819 | 1.538 | – | 1.986 | 1.568 |
| NBO (LPN occupancy) | 1.900 | 1.909 | 1.918 | 1.866 | 1.867 | 1.867 | 1.897 | 1.908 | 1.918 | 1.888 | 1.898 | 1.907 |