Table 1.
Photophysical properties of newly synthesized MARS model compounds.
| MARS | Nitrile | Core | Number of ring expansions | Measured Raman shift (cm−1)a | Predicted Raman shift (cm−1) | λabs (nm)b | RIEc |
|---|---|---|---|---|---|---|---|
| 1 | C≡N | O | 0 | 2241 | 2241 | 670 | 75 |
| 2 | 1 | 2240 | 2240 | 675 | 86 | ||
| 3 | 2 | 2239 | 2239 | 680 | 93 | ||
| 4 | 3 | 2238 | 2238 | 690 | 108 | ||
| 5 | 4 | 2237 | 2237 | 700 | 120 | ||
| 6a | C≡N | O | 3 | 2238 | 2238 | 690 | 111 |
| 6b | C≡15N | 3 | 2210 | 2210 | |||
| 6c | 13C≡N | 3 | 2184 | 2184 | |||
| 6d | 13C≡15N | 3 | 2155 | 2156 | |||
| 7a | C≡N | C | 3 | 2228 | 2230 | 760 | 435 |
| 7b | C≡15N | 3 | 2200 | 2202 | |||
| 7c | 13C≡N | 3 | 2176 | 2176 | |||
| 7d | 13C≡15N | 3 | 2147 | 2148 | |||
| 8a | C≡N | Si | 3 | 2222 | 2222 | 790 | 940 |
| 8b | C≡15N | 3 | 2195 | 2194 | |||
| 8c | 13C≡N | 3 | 2171 | 2168 | |||
| 8d | 13C≡15N | 3 | 2141 | 2140 |
a, bMeasured in DMSO solution. See supplementary information for spectroscopic data measured in PBS buffer.
cRIE: relative intensity v.s. EdU (5-ethynyl-2’-deoxyuridine) with the same SRS acquisition parameters.