Synthesis and magnetostructural properties of two crystalline phases of [CuBr2(sp)] (sp=(−)-sparteine)

Mass spectrometry of metal complexes of bis-quinolizidine alkaloids: electron ionization and fast atom bombardment mass spectral study of copper(II) (-)-sparteine and (-)-alpha- isosparteine complexes

The electron ionization (EI) and fast atom bombardment (FAB) mass spectral fragmentations of ten copper(II) dichloride (dibromide, diformate, diacetate and dithiocyanate) complexes of (-)-sparteine and (-)-alpha-isosparteine were investigated. Fragmentation pathways, elucidation of which was assisted by accurate mass measurements and metastable transitions (EI-MS), as well as FAB/collision-induced dissociation (CID) mass spectral measurements are discussed. The data obtained create the basis for the differentiation of the ligand (sparteine or alpha-isosparteine) in the investigated complexes. The comparison of the results with those obtained previously for corresponding zinc(II) complexes forms the basis for the differentiation of metals in these compounds. The results show that both EI-MS and FAB-MS are very useful tools for the differentiation of ligands, as well as metals in the series of Zn(II) and Cu(II) dichloride (dibromide, diacetate, diformate, dithioacetate) complexes of (-)-sparteine and (-)-alpha-isosparteine.

Magnetic Properties and Crystal Structure of a One-Dimensional Phase of Tetrakis(μ2-benzoato-O,O‘)-bis(dimethyl sulfoxide)dicopper(II)

A new crystalline polymorphic phase of tetrakis(mu2-benzoato-O,O')-bis(dimethyl sulfoxide)dicopper(II) was obtained by direct synthesis, in space group P2(1)/n. The copper coordination is in a slightly distorted square pyramidal geometry with an intramolecular Cu...Cu distance of 2.6494(8) angstroms. The Cu-O distances of the two copper in a dimer are different, giving different chemical environments for each Cu ion. The crystal structure is built up of well-separated stacking columns oriented along the b-axis, with units uniformly spaced, producing a one-dimensional (1-D) zigzag chain through Cu(II)-S...S-Cu(II) interdimer interactions [S...S separation: 3.975(2) angstroms]. Magnetization measurements in the range 2-300 K indicate two magnetic orderings, at low temperature (T < 10 K) a weak ferromagnetic ordering is observed, and above this temperature an antiferromagnetic behavior takes place. ESR spectra at 300 and 77 K of a polycrystalline sample show the characteristic signal of zero-field with D = 0.354 cm(-1), consistent with a ferromagnetic Cu...Cu exchange interaction at low temperature.