Table 3. Knoevenagel Reaction between Malononitrile and Benzaldehyde Catalyzed by 1–4 in Ethanol.

entry	catalyst (mol %)	optimized catalyst quantity	time (m)	yield (%)
1	[Zn(pdca)·(H2O)2]	5 mol %	5	47
			10	67
			15	82
			20	92
			25	97
2	[Cd(pdca)·(H2O)2]	5 mol %	5	59
			10	83
			15	92
			20	95
			25	98
3	[Co(pdca)·(H2O)2]	5 mol %	5	53
			10	69
			15	83
			20	93
			25	96
4	[(CH3)2NH2][CuK(pdca)(PA)(NO3)2]	5 mol %	5	51
			10	74
			15	85
			20	92
			25	95