Solvent-controlled generation of two pairs of mononuclear single-strand helical copper(II) complexes of 2,6-pyridinediylbis(2-pyridinyl)methanone: metal-promoted hydrolysis and solvolysis with asymmetric induction

Two pairs of stable mononuclear single-strand helical complexes were obtained through controlled self-assembly using 2,6-pyridinediylbis(2-pyridinyl)methanone (L) and copper(II) salts. CuL(NO3)2 (1) and [CuL′(H2O)](NO3)2 (2) represent a pair in which L takes the diketo form in 1 but hydrolyzed in 2, while CuLCl2 (3) and [CuL″Cl]Cl (4) constitute another pair in which L remains intact in 3 but solvolyzed in 4. A mechanism of the metal-promoted hydrolysis and solvolysis of ligand L with asymmetric induction is proposed through studies on the crystal structures of these complexes.