Synthesis and spectroscopy of diethyl (pyridinylmethyl)phosphates and their palladium (II) complexes: X-ray crystal structures of Pd(II) complexes

The synthesis of diethyl (pyridin-2-, -3-, -4-ylmethyl)phosphate (2-pmOpe, 3-pmOpe, 4-pmOpe) ligands and their palladium (II) complexes of general formula trans-[PdCl₂L₂] (L = 2-pmOpe, 3-pmOpe,4-pmOpe) has been described. Pyridine phosphate derivatives were synthesized via the condensation of phosphorochloridic acid diethyl ester with an appropriate pyridinylmethanol in the presence of triethylamine. The compounds have been identified and characterized by IR, far-IR, ¹H NMR, ³¹P NMR, ³¹P CP-MAS NMR and elemental analyses. The crystal and molecular structures of palladium (II) complexes, i.e., [PdCl₂(2-pmOpe)₂] and [PdCl₂(4-pmOpe)₂] determined by the X-ray diffraction method, are presented. In both structures, Pd(II) ions are four-coordinated by two chlorine atoms and two pyridine nitrogen atoms. The geometry of complexes is square-planar and adopt a trans configuration, which is consistent with preparation method.     

Heavy metals in the brain of long-tailed duck (Clangula hyemalis) wintering in the Pomeranian Bay,Poland

Males (n=34) and females (n=23) of long-tailed duck (Clangula hyemalis) collected on the southern coast of the Baltic Sea in winter were studied to determine brain tissue concentration of iron (Fe), zinc (Zn), copper (Cu), manganese (Mn), and cadmium (Cd). There were no significant differences in the concentration of metals between males and females, except for Cd, the concentration of which in male brains was twice that of the females. In the brains of 20 birds (41% male and 26% female), the lead (Pb) concentration exceeded 1 μg/g wet wt. In all the duck brains examined, Spearman correlation coefficients were significant and positive for Zn−Mn, Cu−Mn, Cu−Fe, and Pb−Fe; a negative correlation was found for Pb−Zn. Additionally, female brains showed a positive correlation between Pb and Fe. The results obtained were compared with literature data for diving and nondiving anseriforms and birds of other taxa. It seems that concentration of heavy metals in the brain tissue of birds reflect natural adaptations (e.g., for diving) as well as effects of environmental pollution.