The preparation and structure of [trans-dichloro-{trans-6,13-dimethyl-6,13-bis-(N,N-dimethylformamidinyl)-1,4,8,11-tetraazacyclotetradecane}nickel(II)] diperchlorate dihydrate

Reaction of (trans-6,13-diamino-6,13-dimethyl-1,4,8,11-tetraazacyclotetradecane)nickel(II) perchlorate with oxalyl chloride in dimethylformamide forms trans-dichloro-(trans-6,13-dimethyl-6,13-bis(N,N-dimethylformamidinyl)-1,4,8,11-tetraazacyclotetradecane)nickel(II) diperchlorate dihydrate. This has a centrosymmetrical cation with nickel(II) in octahedral coordination by the four secondary amine nitrogen atoms of the macrocycle, and with chloride ions coordinated axially. The 6,13-diamino substituents have been converted to N,N-dimethylformamidinyl (single bondCsingle bondN+H=CHsingle bondN(Me)2) substituents, which are equatorially oriented. The Nsingle bondC and Csingle bondN distances of the formamidinyl group are approximately equal, with bond angles about the C and two N atoms all near 120°, with the group single bondC(Me)single bondNHsingle bondCHsingle bondN(Me)2 approximately coplanar, indicating approximately equal contributions from the canonical forms single bondCHsingle bondNHsingle bondCH=N+(Me)2 and single bondCsingle bondN+H=CHsingle bondN(Me)2.