Coordination behaviour of 2,2′-bipyridine towards the dichloroacetates of zinc and cadmium

Abstract

The coordiantion compounds [Zn(C 10 H 8 N 2 ) (Cl 2 HCCOO)(H 2 O) 3 ] -Á[Zn(C 10 H 8 N 2 )(Cl 2 HCCOO) 3 ] ? and [Cd(C 10 H 8 N 2 ) 2 (Cl 2 CHCOO) 2 ] were synthesised and characterised by elemental and thermal analysis, IR and UV-VIS spectroscopy, and X-ray crystallography. The complexes are air stable and well-soluble in water. The zinc atoms are five and six coordinated and the cadmium atom is six coordinated. The coordination polyhedra of central atoms can be described as trapezoidal pyramid and octahedron in zinc compound and as rectangular bipyramid strongly distorted towards skew trapezoidal bipyramid in cadmium compound. In both compounds all dichloroacetate groups are monodentate. The bond valences considerations show that all 2,2 0 -bipyridine molecules are bonded almost 2 times stronger than carboxylate groups. In the structure of zinc compound exist O-HÁÁÁO hydrogen bonds and in both structures can be found weak C-HÁÁÁO hydrogen bonds. Additionally, both compounds are pile-stacked by pÁÁÁp interactions. The IR spectra show typical vibrations for chelating 2,2 0 -bipyridine molecules and terminal monodentate carboxylate groups. The thermal decomposition studies show zinc compound decomposes in 4 steps and cadmium compound decomposes in 5 steps with formation of oxides as a final products. The ligands decompose gradually, first dichloroacetates and next 2,2 0 -bipyridine.

New fluorescent compounds based on zinc thiocyanate: influence of structure on spectral properties

“…The value of R Zn-S redetermined for coordination compounds, as was described previously (Trzesowska et al, 2004(Trzesowska et al, , 2005(Trzesowska et al, , 2006, was 2.092 Å . The values R Zn-O = 1.6950 Å and R Zn-N = 1.7588 Å were taken from literature data (Kruszynski, 2010). The computed bond valences showed that in (I) the strongest coordination bond is the Zn1-N6 bond ( ZnN = 0.609 v.u.…”

Alkali metal halogenides coordination compounds with hexamethylenetetramine

“…In lithium compounds the hmta molecules are located in the outer coordination sphere and in sodium, potassium and rubidium compounds in the inner coordination sphere. The thermal decomposition of studied compounds proceeds via halogenides or metal oxides with evolving halogens [62][63][64] (Fig. 9).…”

Water-stable and hydrophobicity tunable organolead halide materials with Pb–N coordination for electrochemical CO2 reduction

“…The coordination interaction between organic ligands and metal ions with much higher bond energy (Scheme 1) is generally used in metal-organic frameworks, however, it has rarely been explored in hybrid perovskites. [25][26][27] The heterocyclic aromatic ligands of bipyridine (Bpy, such as 4,4Bpy and 2,2Bpy) are hydrophobic and electron-conjugated heterocyclic aromatic ligands, featuring two N atoms with a lone pair of electrons, and have been extensively utilized in the areas of coordination chemistry and serve as an ideal platform to design intrinsic water-stable organo-lead halide crystalline materials by constructing Pb-N coordination structures. 28 Also, owing to the presence of an empty p orbital in Bpy, the corresponding Pb-N coordination structures may possess chargetransfer features in the visible spectrum, which endow the targets with good photoelectronic properties.…”