Compounds of amine-imine macrocycles: Syntheses and structures of compounds of aza-macrocycles with amine-β-imine ring segments

Abstract

Facile reactions with acetone of Ni(II) and Cu(II) compounds of aliphatic diamines NH2–(CH2)n-NH2, n = 2–4, form compounds of diamine-di-imine tetraaza macrocycles with 14–18 ring members with –NHCCCN- ring segments. Compounds with the imine nitrogen atoms coordinated trans are formed by both metal-ions, compounds with adjacent imine nitrogen atoms, which coordinate cis, are formed by Ni(II) for 14-membered rings and by Cu(II) for 14–18-membered rings. Reactions with acetone of Ni(II) and Cu(II) compounds of propane-1,2-diamine form only trans-di-imine macrocycle compounds. Reactions of Ni(II) and Cu(II) compounds of ethane-1,2-diamine with butanone form both trans- and cis- imine macrocycle compounds.Mono-protonated salts of ethane- and propane-1,2-diamine react with acetone or αβ-ene ketones to form di-protonated salts of 1,4,8,11-tetraaza-cyclotetradeca-4,11-diene, with a variety of C-substituents, from which compounds of transition metal ions can readily be prepared. Reactions of butane-1,4-diamine and hexane-1,6-diamine salts with acetone form analogous 18- and 22-membered trans-diamine-diimine macrocycle salts. Reactions of cyclohexane-1,2-, and propane-1,3-diamine salts with methyl vinyl ketone form tricyclic-14 and 16-membered diamine-diimine macrocyclic salts, respectively.Reactions of diamines NH2–(CH2)n-NH2, n = 2–6 with acetone (and for n = 2 with butanone) form cis- and trans- diamine-diimine macrocycles, without metal-ion or proton mediation. The uncoordinated 14-membered trans-diene macrocycles are relatively stable. Ethane- and propane-1,2-diamines react with αβ-ene ketones to form 1,4-diazapines, which form 1,4,8,11-tetraazacyclotetradeca-4,11-diene compounds with Ni(II) and with acid.The reaction of [H2(ethane-1,2-diamine)](ClO4)2 with acetone forms a bis(β-amino ketone) salt, 4,4,9,9-tetramethyl-5,8-diazonium-dodeca-2,11-dione perchlorate, which reacts with Ni(II) and Cu(II) compounds of diamines to form compounds with 14–18 ring members, with cis coordinated imine functions.The Ni(II) and Cu(II) diamine-di-imine macrocyclic cations are hydrolysed slowly in acid, but the metal-ions are released rapidly by reaction with cyanide. The imine functions of the Ni(II) macrocyclic cations are reduced by catalytic hydrogenation and by NaBH4, to form cyclic tetraamine cations. The Ni(II) diamine-di-imine macrocyclic cations, and analogous Fe(II) cations, are oxidatively dehydrogenated to form amine-tri-imine and tetra-imine macrocycle cations. The imine functions of the Ni(II) cations undergo nucleophilic substitution with nitromethane in base to add nitromethyl substituents, which can coordinate as nitronato-methyl pendant chelates. The nitromethyl groups can be reduced to form amino-methyl substituents which can coordinate as amine pendant chelates.The structures of these macrocycles and their compounds which are included in the Cambridge Crystallographic Data Centre data base are listed.