Design and synthesis of two macrocyclic dinuclear coordination polymers with binding of nitric oxide

•Two new coordination polymers of Robson-type macrocycles, {[CuL1]n (1) and {[CuL2]n (2) were synthesized.•The polymers show one-dimensional infinite chain.•The NO absorption experiments showed the binding NO to these two macrocyclic metal Cu(II) complexes is non-reversible, and the complexes can serve as potential NO scavenger.

Two new coordination polymers of Robson-type macrocycles, {[CuL1]n (1) and {[CuL2]n (2), were obtained by the condensation between bapa and N,N′-bis(3-formyl-5-R-salicylimine)-1,2-propylenediimine in the presence of Cu(II). These polymers have the common feature that the 3-methylaminopyridine group in one ligand coordinates to the metal ion in the neighboring coordination unit, leading to the formation of one-dimensional infinite chain. The formation of NO complexes has been confirmed by UV/Vis spectrophotometry. The binding constants were calculated to be 8.18 × 102 M− 1, 1.2 × 103 M− 1 for 1 and 2, respectively. The control experiments revealed there was non-reversible binding of NO, which can be ascribed to specially coordination environment of the central Cu(II) ions. Moreover, the interactions of the complexes with calf thymus DNA (CT-DNA) have been measured by agarose gel electrophoresis, and the results showed that they can not cleavage the CT-DNA. These two complexes can be served as potential NO scavengers.Graphical abstractTwo new coordination polymers of Robson-type macrocycles, {[CuL1]n (1) and {[CuL2]n (2), were obtained by the condensation between bapa and N,N′-bis(3-formyl-5-R-salicylimine)-1,2-propylenediimine in the presence of Cu(II). The NO absorption experiments revealed a moderate binding to NO and control experiments showed the non-reversibility of the binding NO to these two macrocyclic metal Cu(II) complexes.

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