Conversion of some substituted phenols to the corresponding masked thiophenols, synthesis of a dinickel(II) dithiolate macrocyclic complex and isolation of some metal- and ligand-based oxidation products

A modified preparation of the masked thiolate head unit S-(2,6-diformyl-4-methylphenyl) dimethylthiocarbamate 6 is detailed and two new masked thiolate head units, S-(2,6-diformyl-4-tert-butylphenyl) dimethylthiocarbamate 7 and S-(2-formylphenyl) dimethylthiocarbamate 8, are prepared by this method. The synthesis, crystal structure, NMR spectra and electrochemical properties of the first macrocyclic complex to be derived from 7, [Ni(2)L1](ClO4)(2), are discussed. Oxidation of [Ni(2)L2](CF3SO3)(2) (L2(2-) is derived from 6 and 1,3-diaminopropane) with cerium(IV) ammonium nitrate led to the precipitation of the black complex [Ni(2)L2][Ce(NO3)(6)], which is believed to contain a single nickel(III) centre. This complex decomposes in DMF over time (approximate to 24 hours) to form the red dinickel(II) complex [Ni(2)L2](NO3)(2). 2DMF which has been structurally characterised. Oxidation of [Ni(2)L3](CF3SO3)(2) (L3(2-) is derived from 6 and 1,4-diaminobutane) with I-2 results in ligand oxidation forming the metal free macrocycle (L3')(2+) which contains two five membered isothiazole rings. This is confirmed by the X-ray crystal structure determinations of (L3')(I-3)(2) and (L3')(I)(2)(I-2)(5).