Synthesis and structural analysis of two cyclam derivatives

Abstract

Two macrocycle derivatives (1 and 2) from the modification of 1,4,8,11-tetraazacyclotetradecane (cyclam) have been synthesized and structurally characterized. The synthesis was straightforward and led to the production of the final products at high yields and purity. Central rings of both compounds at solid state display a chair conformation with the substituents dangling around the cyclam ring. The binding cavity radii from the crystal structures are 1.349 Å in the unsubstituted precursor cyclam, 1.926 Å in 1, and 2.140 Å in 2. A computational study provided similar bond matrices but slightly larger cavity sizes, likely as a result of the spacious environment and elasticity of the molecules at gas phase. This research provided an intensive look into the modification of polyamine, which further implicates how the molecule could be manipulated to adjust its properties and functions.