Homochiral 1D Helical Chain Based on an Achiral Cu(II) Complex

Self-assembly of an achiral [Cu­(L)] complex produced a homochiral helical chain [Cu­(L)]3·2H2O (1) (L = 2-dimethylaminoethyl­(oxamato)). Interestingly, complex 1 obtained in our laboratory exhibits only a left-handed helical chain without any chiral source. Single-crystal X-ray analysis revealed the absolute structure and homochirality of its helical chain structure in the space group of P32. Solid-state circular dichroism (CD) spectra confirmed the high enantio excess of the crystals obtained in different synthesis batches. Magnetic susceptibility measurements reveal a relatively strong intrachain antiferromagnetic interaction between Cu­(II) centers via an oxamato bridge (J = −74.4 cm–1).