Bromination of the 3-Chloroanilinium Cation: Structure of a Novel Two-Dimensional Copper(I) Bromide Lattice Prepared via In-Situ Redox Processes

The prolonged reactions of 3-chloroaniline with CuBr2 in HBr solution yielded three crystalline compounds
involving brominated anilinium cations. The first, (C6H3BrClNH3)Br, is the bromide ion salt of the 6-bromo-3-chloroanilinium cation. The compound is monoclinic, space group P21/c, with a = 10.520(4), b = 8.4238(13), c
= 10.502(4) Å and β = 108.55(1)° with Z = 4. The compound with stoichiometry (C6H3BrClNH3)2CuBr3, contains
the 4-bromo-3-chloroanilinium cation. It is triclinic, space group P-1, with a = 8.217(2), b = 14.496(4), c =
16.993(4) Å, α = 77.46(2), β = 86.00(3), γ = 89.22(2)° with Z = 4. Finally, the third compound contains the
dibrominated cation, 4,6-dibromo-3-chloroanilinium, with stoichiometry (C6H3Br2ClNH3)CuBr2. It is orthorhombic,
space group Pnma, with a = 7.2177(2), b = 29.7188(3), and c = 10.9309(2) Å with Z = 8. The latter two salts
contain Cu(I) species, obtained by the reduction of the original Cu(II) ions during the bromination process. The
first of these two Cu(I) salts contain Cu2Br64- dimers in which two CuBr4 tetrahedra share edges. The last compound
contains a unique two-dimensional lattice composed of corner shared Cu2Br6 species.