D/L-mandelic acid-based three new Pb(II) coordination polymers: Influence of temperature and 5,5′-dimethyl-2,2′-dipyridyl ancillary ligand on constructuring enantiomeric coordination polymers.

• The influence of temperature on constructuring enantiomeric coordination polymers. • The influence of ancillary ligand on constructuring enantiomeric coordination polymers. • The luminescent properties of enantiomeric coordination polymers in the solid state. Three new Pb(II) coordination polymers, namely [Pb 2 (mand) 2 ] n (1), {[Pb(L -Hmand)(NO 3)(5,5′-DM-2,2′-bipy)]·2H 2 O} n (2- L ), {[Pb(D -Hmand)(NO 3)(5,5′-DM-2,2′-bipy)]·2H 2 O} n (2- D ) (H 2 mand = D / L -mandelic acid, 5,5′-DM-2,2′-bipy = 5,5′-dimethyl-2,2′-bipyridyl), have been prepared. Their structures have been determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, powder X-ray diffraction and thermogravimetric analyses. Complex 1 crystallizes in the triclinic system with space group P -1, and displays a 2D layer structure. Complexes 2- L and 2- D are pairs of enantiomers. They crystallize in the same chiral space group P 2 1 2 1 2 1 and feature a 1D chain structure. The influence of the temperature and steric-hinerance of 5,5′-dimethyl-2,2′-dipyridyl molecules on constructing enantiomeric Pb(II) coordination polymers based on chiral mandelic acid ligands have been demonstrated. In addition, the circular dichroism (CD) spectroscopy of 2- L and 2- D exhibit obvious positive or negative Cotton effects indicating their homochirality. The luminescent properties of 1 , 2- L and 2- D in the solid state have also been investigated. [ABSTRACT FROM AUTHOR]