A two-step route to a range of fully N-alkylated azamacrocycles has been developed; the crystal structure of tran~-[Ni(Ll)(NCS)~] (L1 = 1,4,8,1 l-tetrapropyl-l,4,8,1 I -tetraazacyclotetradecane) shows the nickel(ii) to be sixcoordinate, but with the uncommon (R,S,R,S)-or trans-(1)-set of N-configurations.Although a few tetra-N-alkyl derivatives of 1,4,8,11-tetraazacyclotetradecane (cyclam) such as L2-L4 have been known for some time,1-4 a convenient synthetic route to a wider range of simple N-alkylated azamacrocycles (e.g. cyclam with R = ethyl, propyl, butyl . . .) has not been reported. Such ligands
279ChemInform Abstract The two pentaaza macrocyclic ligands (VI) containing an exocyclic pyrrolidinylalkyl group are prepared as shown in the scheme. The pyrrolidinylethyl derivative (VIa) reacts with (M(DMSO)6)(ClO4)2 (M: Ni, Cu) in ethanol to yield the isomorphous octahedral complexes (VII) with five-coordinated macrocycle and one coordinated perchlorate. This structure is confirmed by X-ray structural analysis of theNi complex (space group P21/c, Z=4). Both the complexes (VII) can be protonated to give the four-coordinated complexes (VIIIa) in which the pendant arm is protonated and non-coordinating. The analogous square-planar complexes (VIIIb) are formed directly by treatment of (M(DMSO6)(ClO4)2 with the pyrrolidinylpropyl macrocycle (VIb) (only for (VIIIb) (M: Ni) yield given in g; space group P21/n Z =4).
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