Differential study on the transition from a new polyhalogen-substituted unsymmetric salamo-based ligand to its Cu(II) and Co(II) complexes

Two structurally different Cu(II) and Co(II) complexes, [Cu(L)] (1) and [Co-2(L)(2)]center dot 2CH(3)OH (2), constructed from a new polyhalogen-substituted unsymmetric salamo-based ligand (H 2 L, 4-chloro-4'-bromo-6bromo-6'-tert-butyl-2,2'-lethylenedioxybis(nitrilomethylidyne)]diphenol) were synthesized by wet-chemical methods. Complexes 1 and 2 were characterized through elemental analyses, IR and UV-vis spectroscopies and single crystal X-ray crystallography. In addition, the differences of the structures, electronic absorption characteristics and fluorescence property transitions from the ligand to complexes 1 and 2 were studied. The largest difference is that the ligand H2L can react with M(OAc)(2) (M -Cu(II) and Co(II)) to give two complexes with distinct structures and behaviors. There are two chemically identical but crystallographically independent structural units (molecules A and B) in 1. Moreover, each Cu(II) ion (Cut or Cut) is four-coordinate and possesses a square planar geometry, but both Co(II) ions of 2 are bridged by phenoxide ions and possess five-coordinate trigonal bipyramidal configurations. At the same time, Hirshfeld surface analyses showed there are short-range interaction features from the ligand to complexes 1 and 2, the O center dot center dot H/H center dot center dot center dot O interactions of the ligand are significantly stronger than those of 1 and 2. [GRAPHICS] .

Automated summary

Two structurally different Cu(II) and Co(II) complexes were synthesized using a new polyhalogen-substituted unsymmetric salamo-based ligand. The complexes were characterized and their structural, absorption, and fluorescence properties were studied.