Novel Linear Trinuclear Cu^II Compound with Trapped Chiral Hemiaminal Ligand: Magnetostructural Study

Abstract

A new trinuclear CuII compound {[Cu3(HL′)2(H2O)2](ClO4)4}·(H2O)4 (1) was obtained and presented a trapped chiral hemiaminal (HL2′ = [(5-amino-4H-1,2,4-triazol-3-yl)amino](1H-imidazol-4-yl)methanol)). Compound 1 shows an almost flat cationic structure [Cu3(HL′)2(H2O)2]4+ with a Cu3 linear core reached by the double Cu-OR/NN-Cu triazole/alkoxo bridge of the hemiaminal molecule. The CuII spin carriers are antiferromagnetically coupled, presenting a spin doublet ground state (S = 1/2) with a magnetic coupling constant of −179 cm−1. Moreover, DTF calculations show that the planarity of the compound permits a sigma-type overlapping between the unpaired electrons of the spin carriers and the p-type orbitals of the coordinated N and O atoms producing an electronic delocalization through the bridging ligand responsible for the strong antiferromagnetic interactions observed experimentally.

Keywords

• coordination compound
• molecular magnetism
• copper
• hemiaminal