Computer modeling of self-assembly of the crystal structure of zeolite Na384[Al384Si384O1536] (H2O)422 (LTN, cF4080) from suprapolyhedral cluster precursors AB 2 (A-K 48, B-K 24)

Combinatorial and topological analyses and a simulation of the self-assembly of zeolite crystal structure Na384Al384Si384O1536 center dot 422H(2)O (LTN, sp. gr. ) have been performed using computer methods (TOPOS program package). A cubic cell with the parameters a = 36.95 and V = 50 449 (3) contains 768 framework-forming AlO4- and SiO4 tetrahedra (T tetrahedra). The method of complete expansion of a 3D factor graph in nonintersecting cluster substructures in the tetrahedral T framework was used to reveal nanocluster precursors: A composed of 48 T tetrahedra (A-K-48) and B composed of 24 T tetrahedra (B-K-24). The nanocluster precursors A and B correspond to the polyhedral T clusters (tiles) 48T-grc and 24T-toc; they are involved in the matrix self-assembly of the crystal structure within the supracluster AB (2). The centers of clusters A and B occupy the positions of Mg and Cu atoms in the Laves net AB (2) = MgCu2; i.e., the zeolite structure is a suprapolyhedral analog of an intermetallic compound. The self-assembly code of a 3D structure from complementary bound nanocluster precursors is completely reconstuctured in the following form: supracluster -> primary chain -> microlayer -> microframework -> ...framework. The localization of the Na+ template cations in the 6T- and 8T rings of nanocluster precursors A and B and Na+ spacer cations in the 28T-ltn tile with the formation of tetrahedral configuration and in the center of 6-ring, which arises as a result of bonding two B nanoclusters, is established.