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We have synthesized structurally reinforced chiral pentaaza-fifteen-membered polyamines 1 and 2 with a dibridge for the purposes of studying the size-match selectivity of the macrocyclic cavity. Particularly, an attempt has been made to synthesize copper(II) complexes of 1 and 2 to characterize the size-match selectivity of the polyamines in term of microscopic details of the metal-ion binding site. For this purpose the use of ESR spectroscopy has been invoked before X-ray structural analyses of the complexes are carried out. Powder-pattern ESR spectra of the copper(II) complex of 1 in crystalline solid have revealed a temperature dependence of the copper hyperfine structure. This finding suggests that a vibronic effect features in the hyperfine spectra, showing that the pentaaza-macrocycle under study accommodates copper(II) ion and the macrocycle is flexible to exert “genuine” size-match selectivity.

Two structurally reinforced chiral 15-membered azamacrocycles (2S, 14S)-2,14-diisobutyl-10-methyl-1,4,7,10,13 -pentaazabicyclo[11.2.2]heptadecane and (2S,14S)-2,14-diisobutyl-7,10-dimethyl-1,4,7,10,13-pentaazabicyclo[11.2.2] heptadecane as a new type of ligand were conveniently synthesized by LiA1H4 reduction from their corresponding macrocyclic pseudopeptides cyclo[(2S,3′S)-2-(3′-isobutyl-2′-oxopiperazine-1′-yl)-4-methyl-pentanoyl-glycyl-glycyl-sarcosyl] and cyclo[(2S, 3′S)-2-(3′-isobutyl-2′-oxopiperazine -1′-yl)-4-methyl-pentanoyl-glycyl-sarcosyl-sarcosyl], respectively. Their copper(II) complexes were also prepared and characterized.