An array of pyridine-ester enolate based organoboron complexes has been designed and synthesized via a one-pot cascade of Pd-catalyzed α-arylation and BF2 complexation. The rapid structure-activity relationship (SAR) studies indicated that unsymmetrical N,O-chelated BF2 complexes were highly fluorescent in solid state, and exhibited large Stokes shifts, excellent photostability, along with insensitivity to pH. The α-aryl group could not only modulate the electronic effect but also inhibit the intermolecular π-π stacking to promote the aggregation-induced emission (AIE) effect. DFT calculations and experiments identified that the intramolecular charge transfer properties of these N,O-chelates could be switched by the modification of substituents, resulting tunable fluorescence wavelengths. Furthermore, post-complexation modification was accomplished, including Suzuki-Miyaura cross-coupling, Buchwald-Hartwig amination, oxidative cleavage, along with a unique triple substitution reaction involving propargyl Grignard reagents. The exemplificative application of dimethylamine substituted boron complex as a reversible acidic vapor sensor was also demonstrated.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |