No abstract

The complex [Cu4(tu)7](SO4)2·H2O was isolated by addition of thiourea to a copper(II) sulfate electrolyte solution consisting of 2 M H2SO4 and 0.7 M CuSO4. The crystal structure of this complex was solved by X-ray methods and highlighted a [Cu4(tu)7]4+ adamantane cluster. A copper(I)−thiourea cluster of this stoichiometry has not been previously reported. The X-ray structure is refined to residual R = 0.0447 for 4093 observed reflections. Crystals are orthorhombic, of space group Pbca, with Z = 8 in a cell of dimensions a = 10.414(3), b = 17.909(3), and c = 35.818(3) Å. The copper atoms lie in a tetrahedral arrangement in which one of the copper atoms is four-coordinate, while the other three display trigonal planar coordination with Cu···Cu distances of 2.899(2)−2.967(2)Å. The copper−thiourea clusters are interlinked by sulfate ions, which strongly interact with the thiourea ligands through hydrogen bonds. The infrared and Raman spectra of the title compound and of the related copper(I) thiourea complexes [Cu2(tu)5](SO4)·3H2O, [Cu2(tu)6](SO4)·H2O, [Cu4(tu)6](NO3)4·4H2O, and [Cu4(tu)9](NO3)4·4H2O were recorded and assigned, and the dependence of ν(CuS) on the coordination environment of the copper was established.

Substitutions on 5,15-diphenylporphyrin led to the isolation of mono- and di-bromo and mono- and di-nitro derivatives, which were converted into their respective nickel(II) complexes. Reaction of the bromoporphyrins with iodine/silver nitrite resulted in nitrodebromination as well as conventional nitration. The nickel(II) complex of 5-nitro-10,20-diphenylporphyrin was reduced to the 5-amino derivative. The nickel(II) complexes of the bromoporphyrins were converted into the respective mono- and bis-(trimethylsilylethynyl) species. The crystal structures of 5-nitro-10,20-diphenylporphyrin, 5-bromo- 10,20-diphenylporphyrinatonickel(II), and 10,20-diphenyl-5-(trimethylsilylethynyl)porphyrinatonickel(II) were determined.

A new, convenient method for the preparation of functionalised precursors to stable tetraalkylisoindoline nitroxides (aminoxyls) is presented. Simple treatment of 2-benzyl-1,1,3,3-tetramethylisoindoline 2 with Br 2 in CCl 4 gives rapid oxidative debenzylation, generating benzaldehyde and an unusual bromamine, 2-bromo-1,1,3,3-tetramethylisoindoline 4, in high yield. Treatment of the bromamine 4 with FeSO 4 / H 2 SO 4 results in bromination of the aromatic ring in varying yield, while rapid treatment with peroxide / tungstate causes debromination, generating 1,1,3,3-tetramethylisoindoline 3. Bromination of the isoindoline aromatic ring is more readily afforded by treatment of 2-benzyl-1,1,3,3-tetramethylisoindoline 2 with Br 2 and AlCl 3 in CCl 4 , producing 2,5-dibromo-1,1,3,3-tetramethylisoindoline 7 and/or 2,5,6-tribromo-1,1,3,3-tetramethylisoindoline 6 in varying yields depending upon the exact reaction conditions. Rapid treatment with peroxide / tungstate generates the corresponding bromine substituted isoindolines, 5-bromo-1,1,3,3-tetramethylisoindoline 5 and 5,6-dibromo-1,1,3,3-tetramethylisoindoline 8. Prolonged peroxide / tungstate treatment oxidises the substituted bromamines to the corresponding nitroxides, 5-bromo-1,1,3,3-tetramethylisoindolin-2-yloxyl 9 and 5,6-dibromo-1,1,3,3-tetramethylisoindolin-2-yloxyl 10. SQUID magnetic susceptibility measurements of crystalline 10 reveal strong antiferromagnetic interradical spin coupling. The crystal structures of 10, 2-bromo-1,1,3,3-tetramethylisoindoline 4 and the hydrobromide dihydrate salt of 1,1,3,3-tetramethylisoindoline 3 (3a) have also been determined, with 10 displaying an interesting molecular packing arrangement.2