Pressure-Dependent Pseudo-Polymorphism of Polymeric{[Cu2(TBA)]·2H2O}nand Dinuclear [Cu2(TBA)(H2O)2]·2H2O Complexes Based on in Situ Tetramerizationof DMBA.

Twonew pressure-dependent pseudo-polymorphism complexes, a 2D polymeric{[Cu2(TBA)]·2H2O}n(1) and a dinuclear [Cu2(TBA)(H2O)2]·2H2O (2), weresuccessfully obtained and demonstrated to possess weak antiferromagneticproperties. The synthesis has been achieved through a novel one-potreaction where four DMBA (DMBA = 1,3-dimethyl-barbitiric acid) moleculestetramerized in situ with EtOH to give (TBA)4-(H4TBA = 1,1',2,2'-tetra-barbiturate-ethene) ligand. This unprecedented tetramerization involves one-pot formation of onenew CC bond and four new C-C bonds. It was shown thatthe formation of 1strictly relied on the use of Cu(II)ion and EtOH and that reactions of oxidation, Knoevenagel condensation, and Michael addition probably induce the tetramerization. [ABSTRACT FROM AUTHOR]