A chiral mixed carboxylate, [Nd4(H2O)2(OOC(CH2)3COO)4(C2O4)2], exhibiting NLO properties

Reaction of a mixture of neodymium carbonate, HCl, oxamic acid and glutaric acid under hydrothermal conditions gives rise to a new mixed carboxylate of neodymium, [Nd4(H2O)2(OOC(CH2)3COO)4(C2O4)2], I. The structure, determined using single crystal X-ray diffraction, comprises a helical column formed by the grafting of the oxalate unit on to helical NdO9 chains, cross-linked by the glutarate anions. It is noteworthy that the pitch of the helix is equivalent to the length of the oxalate unit. Furthermore, I shows about 1.1 times the SHG activity of urea.