The chemistry of sulphur–nitrogen ligands. Part I. Complex-formation and dealkylation reactions of 1,9-bis(tritylthio)- and 1,9-bis(benzyl-thio)-3,7-diazanonane in the presence of metal(II) salts, and the synthesis of dibromo{3,13-dithia-6,10-diazabicyclo[13.4.0]nonadeca-1(15),16,18-triene}nickel(II)

Abstract

The quadridentate N2S2 donor ligands 1,9-bis(tritylthio)-3,7-diazanonane (L1) and 1,9-bis(benzylthio)-3,7-diazanonane (L2) have been prepared as their dihydrobromide salts and allowed to react with metal(II) acetates (M = NiII, CoII, and HgII) in methanol solution. Both ligands react with HgII with concomitant dealkylation at the sulphur donor atoms to give a trinuclear complex [Hg(HgL)2]Br2·3H2O (L = 3,7-diazanonane-1,9-dithiolato). Treatment of this complex (dissolved in aqueous HCl) with H2S gives the dihydrochloride of 3,7-diazanonane-1,9-dithiol. Dealkylation does not occur in the presence of CoII, the isolated complexes in this case being blue tatrahedral [CoL1]Br2 and purple octahedral [CoBr2(L2)]. Nickel(II) gives the blue octahedral [NiBr2(L2)], but catalyses rapid detritvlation of L1 to give the black. 1diamagnetic, trinuclear complex [Ni(NiL)2]Br2. Reaction of [Ni(NiL)2]Br2, with α,α′-dibromo-o-xylene in methanol solution gives blue dibromo{3,13-dithia-6,10-diazabicyclo[ 13.4.0]nonadeca-1(15),16,18-triene}nickel(II).