A convergent approach to highly functionalized 3-hydroxyisoquinolines is reported. The key steps are an Ugi multicomponent reaction and a subsequent intramolecular reductive Heck reaction; these can also be performed as a one-pot procedure. The structures display very interesting properties as blue-fluorescence emitters. Photophysical studies on the absorption and static fluorescence indicate that the substitution pattern on the pyridyl part influences the optical properties only to a minor extent, unless the amide substituent becomes sterically demanding and leads to significant nonradiative deactivation. The donor substitution on the benzo core considerably enhances the fluorescence quantum yields and trimethoxy substitution causes a pronounced redshift of the emission bands. Protonation of the isoquinolyl nitrogen atom causes efficient static quenching of the fluorescence.

One-pot insertion-coupling-addition synthesis gives piperazinyl indolones showing aggregation induced emission and crystallization-induced emission enhancement.

1-, 3-, and 5-Biarylsubstituted pyrazoles can be efficiently prepared by a microwave-assisted consecutive four-component synthesis based upon a sequential Pd-catalyzed coupling-condensation-coupling (C 3 ), a one-pot sequence which concatenates Sonogashira alkynylation and Suzuki arylation intercepted by pyrazole forming cyclocondensation of the ynone intermediate. This diversity-oriented approach enables tailoring, fine-tuning and optimization of absorption and emission properties towards high fluorescence quantum yields in solution up to F f ¼ 0.97. The increased luminescence intensity stemming from biaryl substitution can be rationalized by ground and excited state computations on the DFT level of theory, which nicely reproduce the experimental data of absorption and emission. † Electronic supplementary information (ESI) available: Synthesis of reference compound 9, 1 H and 13 C NMR spectra, UV/Vis and uorescence spectra of compounds 5, 6, 7, 8, and 9; computed xyz-coordinates of the S 0 state of the pyrazoles 5c, 6d, and 8b, computed UV/Vis spectra of TD-DFT calculated structures of 5c, 6d, and 8b, computed xyz-coordinates of the S 1 state of pyrazole 6d. CCDC 1049137. For ESI and crystallographic data in CIF or other electronic format see Scheme 4 Consecutive C 3 -four-component synthesis of 3-biarylsubstituted pyrazoles 6. 33840 | RSC Adv., 2015, 5, 33838-33854This journal is Scheme 5 Consecutive C 3 -pseudo-five-component synthesis of 3,5bis(biphenyl) 1-methyl pyrazole (7).Scheme 6 Consecutive C 3 -four-component synthesis of 1-biarylsubstituted pyrazoles 8. This journal isView Article Online a PdCl 2 (PPh 3 ) 2 (14.0 mg, 0.02 mmol), CuI (7.62 mg, 0.04 mmol), Et 3 N (106 mg, 1.05 mmol), Cs 2 CO 3 (978 mg, 3.00 mmol), PPh 3 (52.3 mg, 0.2 mmol). b PdCl 2 (PPh 3 ) 2 (29.0 mg, 0.04 mmol), CuI (16.7 mg, 0.09 mmol), Et 3 N (223 mg, 2.20 mmol), Cs 2 CO 3 (2.05 g, 6.30 mmol), PPh 3 (110 mg, 0.42 mmol). This journal is