Structural chemistry of metal inorganic 3D MT frameworks. Templated nanoclusters–precursors Ga2(PO4)2F2 and Ga2(PO4)2(HF)F2 and self-assembly of crystalline gallophosphate structures (NH4)2[Ga2(PO4)2F2](KTP-Type) and (NH4)2[Ga2(PO4)2(HF)F2] (p-KTP-Type)

Abstract

The article discusses the structural chemistry of metal inorganic microporous 3D MT-frameworks of M-octahedra and T-tetrahedra. Geometric and topological simulation has been applied to topologically different suprapolyhedral M2T2 clusters of two octahedra and two tetrahedral, with the hierarchical structure presented in the form of two-colorable graphs. The obtained data have been used during the search for clusters-precursors of metal inorganic microporous 3D MT-frameworks in the arranged database of crystalline MT-structures (13455 compounds, ToposPro program package). For gallophosphates of close chemical composition (NH4)2[Ga2(PO4)2F2] (KTP-type), (NH4)2[Ga2(PO4)2(HF)F2] (p-KTP-type), the complete 3D reconstruction of the cluster self-assembly of crystalline structures has been performed: nanocluster–precursor S 3 0 –primary chain S 3 1 –microlayer S 3 2 –microframework S 3 3 . The simulation involves the methods of combinatorial topology analysis based on plotting a basic 3D net of zeolite in the form of a graph, the nodes of which correspond to the position of the gravity centers of clusters–precursors Ga2(PO4)2F2 for KTP and Ga2(PO4)2(HF)F2 for p-KTP. Both for KTP and for p-KTP the same type of crystal forming 2D nets 333344 + 3344 (1: 1) have been set. Various variants of the complementary bonding of the 2D nets led to the formation of basic 3D nets with CN = 10 (KTP) and 8 (p-KTP). For the first time the functional role of NH4 clusters–templates, which form hydrogen bonds with the O and F atoms and which fix the relative position of the two Ga2(PO4)2F2 and Ga2(PO4)2(HF)F2 clusters, has been considered.