Microwave-Assisted Synthesis of Pd Nanoparticles and Catalysis Application for Suzuki Coupling Reactions

Table 1: The effect of base and solvent on the Suzuki coupling reaction^a.

Entry	Base	Solvent	Yield ^b/%	Yield ^c/%	Yield ^d/%	Yield ^e/%
1	K₂CO₃	EtOH/ H₂O	98.4	97.1	96.7	96.9
2	K₃PO₄·3H₂O	EtOH/ H₂O	96.6	95.8	95.2	95.6
3	NaOH	EtOH/ H₂O	95.3	94.3	92.6	93.5
4	NaOAc	EtOH/ H₂O	95.1	93.7	91.8	94.0
5	NEt₃	EtOH/ H₂O	93.8	93.2	90.4	91.9
6	K₂CO₃	MeOH/ H₂O	96.9	95.9	95.2	95.7
7	K₂CO₃	Toluene/ H₂O	49.1	47.6	45.5	46.4
8	K₂CO₃	CH₂Cl₂/ H₂O	58.4	55.7	53.8	54.9
9	K₂CO₃	CH₃CN/ H₂O	50.5	49.5	46.6	47.1
10	K₂CO₃	THF/H₂O	72.7	71.3	70.8	72.2
11	K₂CO₃	DMF/H₂O	81.3	79.7	78.1	80.4

^a Reaction conditions: 4-bromotoluene (1.0 mmol), phenylboronic acid (1.5 mmol), PdNPs (0.1 mmol‰), base (2.0 mmol), solvent/H₂O (6mL/6mL) for 15 min. ^b PdNPs-EG ^c PdNPs-KBr-EG ^d PdNPs-CA ^e PdNPs-KBr-CA.