Magnetic properties of copper(II) propionate α-picoline

The existence of HC₄N₃ in the gas phase either as cyanoform, HC(CN)₃ (I), or as di-cyanoketenimine, (NC)₂CCNH (II), has recently been discussed and treated by an ab initio calculation [1]. It appeared that I is ca. 10 kcal mol^?1 more stable than II. The present communication reports experimental proof of the occurrence of I as a by-product in two different chemical procedures to be described. In both cases the small yields (< 1°/_oo) of an unstable compound available over a limited period (ca. 2 h) made the use of microwave equipment appropriate since it is well adapted to the study of small quantities (< 1 mg) and in particular to highly polar species such as I and II.     

2-Amino-5-picoline N-oxide complexes formed from various copper(II) salts

Copper(II) complexes with 2-amino-5-picoline N-oxide (2am5PicO = L), CuL₄X₂(X = ClO₄, BF₄, and NO₃), CuL₂X₂ (X = Cl, Br) and CuLX₂ (X = Cl) have been isolated and characterized using spectral methods (i.e. IR, UV-vis and ESR). Coordination occurs via the N-oxide oxygen exclusively with the amine functional group showing only slight tendency to involve itself in hydrogen bonding to the anions. The halide complexes involve the halide ions in the coordination spheres while the polyatomic anions are not bound directly to copper. The latter compounds have monomeric, 4-coordinate CuO₄ chromophores while the former solids are apparently polymeric. Evidence for N-oxide bridging ligands in the CuL₂X₂ solids and halogen bridging in the CuLX₂ solid is presented.     

New chelated complexes of bis-β-carboalkoxyethyltin(IV) dichloride with S-benzyldithiocarbazate Schiff bases

The Schiff bases [H₂SBSaD], [H₂SBVD] and [H₂SBND], derived by the condensation of S-benzyldithiocarbazate and salicylaldehyde, 2-hydroxy-3-methoxybenzaldehyde and 2-hydroxy-1-naphthaldehyde respectively, react with diestertin dichlorides, R₂SnCl₂ [R=? CH₂CH₂CO₂CH₃, ? CH₂CH₂CO₂C₂H₅ or ? CH₂CH₂CO₂C₄H₉] in 1:1 molar proportion to yield chlorine-substituted complexes of the type R₂Sn(Schiff base), the base being tridentate. The complexes are characterized on the basis of their elemental analyses, IR and ¹H NMR spectral studies. The ¹³C and ¹¹⁹Sn NMR and the tin-carbon coupling constant data reveal the structures of the complexes to be octahedral with trans ester grouping, and bidentate ester linkages. The pentacoordinated complex (CH₃)₂Sn(SBSaD) was prepared by the reaction of dimethyltin oxide with H₂SBSaD in equimolar proportions.