Crystal supramolecularity of organic–inorganic hybrids of polyhalides: structures of 2,5-dibromopyrazinium triiodide and 2-bromopyridinium dibromoiodide

Abstract

Crystal structure determinations of the compounds (C 4 H 4 Br 2 N 2 ) þ [I 3 ] 7 , 1, and (C 5 H 5 BrN) þ [IBr 2 ] 7 , 2, have been carried out. In 1, the anion is surrounded symmetrically by four cations. This arrangement results from both (p)NÀ ÀH Á Á Á IÀ ÀIÀ ÀI and IÀ ÀIÀ ÀI Á Á Á BrÀ ÀC(p) intermolecular interactions, tying the cations and anion into sheets of pseudo four fold arrays of cations and anions. The crystal lattice of 2 consists of stacks of cations and anions that are connected via CÀ ÀBr Á Á Á BrÀ ÀIÀ ÀBr, NÀ ÀH Á Á Á BrÀ ÀIÀ ÀBr, and BrÀ ÀIÀ ÀBr Á Á Á IBr 2 inter-stacks intermolecular interactions leading to a supramolecular assembled lattice. The IBr 2 7 anions are also assembled in a nearly T-shaped dimeric motif where one bromide end is interacting with the central iodide atom in another IBr 2 7 unit (IÀ ÀBr Á Á Á I angle of 1548). The extensive anion Á Á Á cation intermolecular interactions in both compounds lead to a crystal supramolecularity.

Molecular self-assembly of 1D linear and 2D T-shape polyiodide arrangements in two organic ammonium triiodide salts: supramolecular structures and density functional theory-based optical properties

“…However, there are also some reports on triiodide salts obtained by treatment of N-or S-donor ligands with metal halides such as LiI, CuI, AgCl, CdI 2 , SnI 2 , PbCl 2 , Hg 2 Cl 2 , SbI 3 , BiI 3 and SnI 4 . 24,[26][27][28][29][30][31] For example, the reaction of BiI 3 with pyrazinethiocarboxamide and diiodine is reported to afford the salt [4A] 4 [I 3 ] 4 •(MeCN) 3 (A: pyrazinethiocarboxamide). 31 Also for compound [Co(C 12 H 8 -N 2 ) 3 ]•(I 3 ) 2 , synthesized solvothermally from Co(NO 3 ) 2 , 1,10phenanthroline, and SnI 2 , the SnI 2 reagent served only as a source of I atoms.…”