Hydroxy-carboxylates of manganese, zinc and cadmium

A structurally unique manganese coordination polymer of 2-hydroxy-4-(1,3-dioxoisoindolin-2-yl)butanoic acid (H2L) namely [{Mn(HL)2(H2O)}·8H2O]n·[Mn(HL)2(H2O)2] (1) is characterized. The coordination polymer is a self-assembly of [Mn(HL)2(H2O)] formed by bridging carbonyl groups of hydroxy-carboxylates. The manganese ions form five membered hydroxy-carboxylate chelates. The unique feature of this coordination polymer is that, it has features of host–guest systems, in which a polymeric host manganese coordination polymer holds neutral [Mn(HL)2(H2O)2] molecules. A linear coordination polymer of zinc, namely [Zn(HL)2(pyr)]·pyr (2) is structurally characterized (pyr = pyridine). The polymer is formed by the self-assembling of monomeric [Zn(HL)2(pyr)] through coordination of carbonyl group of hydroxy-carboxylate. Each zinc ion has five membered hydroxy-carboxylate chelate. Tris-pyridine bis-(4-(1,3-dioxo-1H, 3H-benzo[de]isoquinolin-2-yl)-3-hydroxy-benzoate)cadmium(II)·2pyr·3H2O complex (3) which has two pyridine and three water of crystallization molecules is also characterized. Due to orientation of hydroxy group in 3, it has only chelating carboxylates binding to cadmium.