Abstract:
The novel crystal structures of seven compounds which combine 2-phenylethylammonium cations and
perhalometallate anions, all with the general formula (C8H9NH3
+)2 MX4
2 , were determined to
establish the effect of metal atom and halogen ligand substitution on the structures and hydrogen
bonding interactions. Five of the structures, bis(2-phenylethylammonium) tetrachlorozincate,
(C8H9NH3
+)2 ZnCl4
2 , bis(2-phenylethylammonium) tetraiodozincate, (C8H9NH3
+)2 ZnI4
2 , bis(2-
phenylethylammonium) tetrabromodichloroiodozincate, (C8H9NH3
+)2 ZnCl2BrI2 , bis(2-
phenylethylammonium) tetrabromocadmate, (C8H9NH3
+)2 CdBr4
2 , and bis(2-
phenylethylammonium) tetrabromomercurate, (C8H9NH3
+)2 HgBr4
2 , were found to be isostructural,
while two of the compounds containing iodo ligands, bis(2-phenylethylammonium) tetraiodocadmate,
(C8H9NH3
+)2 CdI4
2 , and bis(2-phenylethylammonium) tetraiodomercurate, (C8H9NH3
+)2 HgI4
2 ,
crystallize in a different, but related disordered structure. Strong N+–H/X –M hydrogen bonding
interactions, as well as weaker C–H/p aromatic interactions occur in all seven structures, and two
robust tetrameric hydrogen bonded zero-dimensional motifs are present in all seven structures. C–H/
Cl–M hydrogen bonding interactions are present in the structure of bis(2-phenylethylammonium)
tetrachlorozincate, and result in the distortion of the geometry of the 2-phenylethylammonium cation.
Comparison of the identified zero-dimensional hydrogen bonding motifs with those occurring in
related structures reported in the literature shows that the motifs are robust and can tolerate changes in
cation, metal and ligand to a large extent.