Copper(II) halide coordination complexes and salts of 3-halo-2-methylpyridines: Synthesis, structure and magnetism

Copper(II) complexes of 2-amino-5-chloro-3-fluoropyridine: syntheses and magnetic properties of (3,5-FCAP)2CuX2 and (3,5-FCAPH)2CuX4

“…In the syn conformation, the amino substituents effectively block one face of the Cu(II) ion, preventing adjacent molecules from approaching each other on that side, thus limiting the bi-halide bridging to formation of a dimeric structure rather than a chain. This has been observed previously in related structures [4,11,41]. In 1, the fluorine substituents do not participate in halogen or hydrogen bonding, so the halogen and hydrogen bonds made by the fluorine substituents in 2 may influence the change from anti to syn.…”

“…The copper ion again lies on a crystallographic inversion center, as for 1. The bond lengths for Cu-Cl1 (2.2621(5) Å) and Cu1-Cl2 (2.2775(6) Å) are comparable to other tetrachlorocuprate salts [4,34,35]. The geometry about the copper ion is nearly square planar with a 89.42(2)°Cl1-Cu-Cl2 bond angle with trans angles of 180°as required by the symmetry.…”

“…This was not the case for 3,5-FCAP, as changing the halide produced changes in both the structures and magnetic properties of the materials. Although copper chloride and bromide compounds are frequently isostructural, the differences observed here are not unique [4,20,41]. What is unique is the specific effects of fluorine in terms of nonbonding contacts and its effect on crystal structures.…”

“…Compound 4 exhibits three short contacts between halides ions of tetrabromocuprate ions (see table 4, figure 11). These contacts form a pleated sheet of CuBr 4 2− groups parallel to the ab-face. The structure is stabilized by multiple hydrogen bonds from 3,5-FCAPH ions (see table 3).…”

“…Synthesis and studies of the structures and corresponding magnetic exchange properties of copper(II) halide coordination complexes and salts have been of interest to our research group for quite some time [1][2][3][4]. These systems merit study due to the low-dimensional anti-ferromagnetic exchange observed and the opportunity to compare and contrast packing motifs to gain insight into magneto-structural correlations.…”