(3,5,7,7,12,14,14-Heptamethyl-1,4,8,11-tetraazacyclotetradec-4-11-diene)nickel(II) revisited and some (2,5,5,7,12,12,14-heptamethyl-1,4,8,11-tetraazacyclotetradecane)nickel(II) compounds

• Synthesis of 3,5,7,7,12,14,14-heptamethyl-1,4,8,11-tetraazacyclotetradec-4-11-diene)nickel(II).
• Synthesis of 2,5,5,7,12,12,14-heptamethyl-1,4,8,11-tetraazacyclotetradecane)nickel(II).
• 3,5,7,7,12,14,14-Heptamethyl- and 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradec-4-11-diene compounds of Ni(II) and of Co(III) co-crystallise.
• 3,5,7,7,12,14,14-Heptamethyl- and 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane compounds of Ni(II) co-crystallise.

The reported preparation of (3,5,7,7,12,14,14-heptamethyl-1,4,8,11-tetraazacyclotetradec-4-11-diene)nickel(II) perchlorate, [Ni(Me7[14]diene)](ClO4)2, by reaction with acetone of equimolar mixtures of [Ni(en)3](ClO4)2 and [Ni(rac-pn)3](ClO4)2 has been investigated. A crystal isolated from this reaction has half the cation sites occupied by [Ni(Me7[14]diene)]2+ cations and half by [Ni(Me6[14]diene)]2+ cations. A tetracyanonickelate salt prepared from this has 72% of the cation sites occupied by the heptamethyl cation. Reduction of the mixed-macrocycle nickel(II) cations, [Ni(Me6/7[14]diene)]2+, with NaBH4 in water forms (cyclic tetraamine)nickel(II) cations. The meso-2RS,7RS,14SR-[Ni(Me7[14]ane)]2+ and 7RS,14SR-[Ni(Me6[14]ane)]2+ cations and the rac-2RS,7RS,14RS-[Ni(Me7[14]ane)]2+ and 7R,14R-[Ni(Me6[14]ane)]2+ cations generally co-crystallise as meso or rac salts, some with stoichiometric formulae. The structures of [Ni(meso-Me6/714]ane)][ZnCl4], [Ni(rac-Me6/7[14]ane)](ClO4)2 and [Ni(meso-Me6[14]ane)] [Ni(rac-Me6/7[14]ane)(acac)](ClO4)3 compounds were determined. Structures of [Ni(meso-Me6[14]ane)][ZnCl4] and [Ni(rac-Me6[14]ane)(acac)]ClO4 were determined for comparison. An equimolar mixture of [H(en)](ClO4)2 and [H(pn)](ClO4)2 reacted with acetone to form a tetraaza macrocycle salt, from which a cobalt(III) compound [Co(Me6/7[14]diene)(acac)](ClO4)2 with ca. 23% of the cation sites occupied by the heptamethyl cation was prepared and structurally characterised.

Reaction with acetone of equimolar mixtures of [Ni(en)3](ClO4)2 and [Ni(rac-pn)3](ClO4)2 or of [H(en)]ClO4 and [H(rac-pn)]ClO4 form compounds of 3,5,7,7,12,14,14-heptamethyl-1,4,8,11-tetraazacyclotetradec-4-11-diene) and the 5,7,7,12,14,14-hexaamethyl homologue. Reduction of the imine groups for the mixture of the nickel(II) diene compounds form the 2RS,7RS,14SR and 2RS,7RS,14RS cyclic tetraamine cations, together with their hexamethyl homologues. The hepta- and hexamethyl cations tend to co-crystallise.Figure optionsDownload as PowerPoint slide