Hydrothermal synthesis and structure of a zinc arsenate–oxalate, [NH3(CH2)3NH2(CH2)3NH3][Zn3(AsO4)(HAsO4)2(C2O4)], and a zinc arsenate, [{NH3(CH3)2NH2(CH3)3NH3}2][Zn6(AsO4)4(HAsO4)3]·H2O, with three-dimensional structures

Two new open-framework solids, a zinc arsenate–oxalate, [NH3(CH2)3NH2(CH2)3NH3][Zn3(AsO4)(HAsO4)2(C2O4)], I, and a zinc arsenate, [{NH3(CH2)3NH2(CH2)3NH3}2][Zn6(AsO4)4(HAsO4)3]·H2O, II, have been synthesized in the presence of dipropylenetriamine (DPTA) under mild hydrothermal reaction conditions. Both I and II possess a three-dimensional architecture with channels. The structure of the zinc arsenate–oxalate, I, consists of anionic zinc arsenate–oxalate layers cross-linked by arsenate units giving rise to 10-membered channels. The zinc arsenate structure, II, on the other hand, is made from the linkages involving zinc arsenate layers and arsenate pillars. The structures of both I and II possess large number of hydrogen bond interactions involving the framework oxygen atoms and the hydrogen atoms of the amine molecule. The synthesis conditions employed and the close structural similarity between the two structures indicates that I could be the precursor for II.