RESUMO
Anhydrous EuII -acetylenedicarboxylate (EuADC; ADC2- = - O2 C-C≡C-CO2 - ) was synthesized by reaction of EuBr2 with K2 ADC or H2 ADC in degassed water under oxygen-free conditions. EuADC crystallizes in the SrADC type structure (I41 /amd, Z=4) forming a 3D coordination polymer with a diamond-like arrangement of Eu2+ nodes (msw topology including the connecting ADC2- linkers). Deep orange coloured EuADC is stable in air and starts decomposing upon heating in an argon atmosphere only at 440 °C. Measurements of the magnetic susceptibilities (µeff =7.76â µB ) and 151 Eu Mössbauer spectra (δ=-13.25â mm s-1 at 78â K) confirm the existence of Eu2+ cations. Diffuse reflectance spectra indicate a direct optical band gap of Eg =2.64â eV (470â nm), which is in accordance with the orange colour of the material. Surprisingly, EuADC does not show any photoluminescence under irradiation with UV light of different wavelengths. Similar to SrADC, EuADC exhibits a negative thermal volume expansion below room temperature with a volume expansion coefficient αV =-9.4(12)×10-6 â K-1 .
RESUMO
The chemical composition of a black powder confiscated by German customs was elucidated. Black powders are occasionally used as a 'transporter' for cocaine and are obviously especially designed to cloak the presence of the drug. The material consisting of cocaine, copper, iron, thiocyanate, and graphite was approached by analytical tools and chemical modelling. Graphite is added to the material probably with the intention of masking the typical infrared (IR) fingerprints of cocaine and can be clearly detected by powder X-ray diffraction (XRD) and Raman spectroscopy. Cu(2+) and NCS(-) ions, when carefully reacted with cocaine hydrochloride, form the novel compound (CocH)2 [Cu(NCS)4 ] (CocH(+) = protonated cocaine), which has been characterised by single crystal XRD, IR, NMR, UV/Vis absorption and EPR spectroscopy. Based on some further experiments the assumed composition of the original black powder is discussed.