Two new zincophosphates, (H3NCH2CH2NH3)2[Zn(μ-PO4)2] and (NH4)[(H3N)Zn{(μ-PO4)Zn}3]: Crystal structures and relationships to similar open framework zinco- and aluminophospates

Two new zincophosphates, bis(ethylenediammonim) catena-bis(μ-phosphato)zincate, (H3NCH2CH2NH3)2[Zn(μ-PO4)2] (1), and ammonium ammine-tris(μ-phosphato)tetrazincate, (NH4)[(H3N)Zn{(μ-PO4)Zn}3] (2), were synthesized under hydrothermal conditions and their crystal structures were determined by single-crystal X-ray diffraction analysis. The crystal structure of 1 consists of infinite macroanionic ZnP2O84− chains, running along the [0 0 1] direction, and diprotonated ethylenediammonium cations, H2en2+. The crystal structure of 2 is built up from ZnO4, Zn(NH3)O3 and PO4 vertex-sharing tetrahedra connected to form an open 3D framework. The ammonium groups, NH4+, are located in the channels formed by 8M-rings extending along [1 0 0]. In order to study vibrational behavior of H2en2+ and NH4+ cations, NH3 molecules in 1 and 2, single-crystal Raman spectra were obtained. Structural, chemical and topological similarities to the other open framework zinco- and aluminophosphates incorporating different guest species are discussed.

Graphical AbstractStructure of 1 (left): polyhedral (a) and ORTEP-like (b) representation of the ZnP2O84− chain with two H2en2+ cations. Structure of 2 (right): polyhedral structure of the layers I and II seen along [1 0 0] (c-axis is vertical).Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Synthesis under hydrothermal conditions and the crystal structures of two new zincophosphates. ► Compound 1 is a new inorganic–organic hybrid compound. ► Structure of 1 consists of infinite macroanionic ZnP2O84− chains and H2en2+ (en=ethylenediamine) cations. ► Structure of 2 is a novel 3D open framework structure with 8M channels. ► Structure of 2 is the first 3D zincophosphate which incorporates both, the coordinated NH3 molecule and NH4+ cations.